WorldWideScience

Sample records for reservoir heterogeneity aquifer

  1. Numerical investigation of temperature distribution in a confined heterogeneous geothermal reservoir due to injection-production

    NARCIS (Netherlands)

    Ganguly, Sayantan; Tan, Lippong; Date, Abhijit; Mohan Kumar, M.S.

    The present study deals with the modeling of transient temperature distribution in a heterogeneous geothermal reservoir in response to the injection-production process. The heterogeneous geothermal aquifer considered here is a confined aquifer with homogeneous layers of finite length and overlain

  2. Characterization of oil and gas reservoir heterogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Tyler, N.; Barton, M.D.; Bebout, D.G.; Fisher, R.S.; Grigsby, J.D.; Guevara, E.; Holtz, M.; Kerans, C.; Nance, H.S.; Levey, R.A.

    1992-10-01

    Research described In this report addresses the internal architecture of two specific reservoir types: restricted-platform carbonates and fluvial-deltaic sandstones. Together, these two reservoir types contain more than two-thirds of the unrecovered mobile oil remaining ill Texas. The approach followed in this study was to develop a strong understanding of the styles of heterogeneity of these reservoir types based on a detailed outcrop description and a translation of these findings into optimized recovery strategies in select subsurface analogs. Research targeted Grayburg Formation restricted-platform carbonate outcrops along the Algerita Escarpment and In Stone Canyon In southeastern New Mexico and Ferron deltaic sandstones in central Utah as analogs for the North Foster (Grayburg) and Lake Creek (Wilcox) units, respectively. In both settings, sequence-stratigraphic style profoundly influenced between-well architectural fabric and permeability structure. It is concluded that reservoirs of different depositional origins can therefore be categorized Into a heterogeneity matrix'' based on varying intensity of vertical and lateral heterogeneity. The utility of the matrix is that it allows prediction of the nature and location of remaining mobile oil. Highly stratified reservoirs such as the Grayburg, for example, will contain a large proportion of vertically bypassed oil; thus, an appropriate recovery strategy will be waterflood optimization and profile modification. Laterally heterogeneous reservoirs such as deltaic distributary systems would benefit from targeted infill drilling (possibly with horizontal wells) and improved areal sweep efficiency. Potential for advanced recovery of remaining mobile oil through heterogeneity-based advanced secondary recovery strategies In Texas is projected to be an Incremental 16 Bbbl. In the Lower 48 States this target may be as much as 45 Bbbl at low to moderate oil prices over the near- to mid-term.

  3. Influence of aquifer heterogeneity on the design and modelling of Aquifer Thermal Energy Storage (ATES) systems

    OpenAIRE

    Bridger, David W.

    2006-01-01

    A modelling study was carried out to evaluate the influence of aquifer heterogeneity, as represented by geologic layering, on heat transport and storage in aquifer thermal energy storage (ATES) systems. An existing ATES system installed within a heterogeneous aquifer system in Agassiz, British Columbia, Canada was used as a case study. Two 3D heat transport models of the study site were developed and calibrated using the heat transport code FEFLOW, including: a "simple" model domain with unif...

  4. The impact of aquifer heterogeneity on the performance of aquifer thermal energy storage

    NARCIS (Netherlands)

    Sommer, W.T.; Valstar, J.R.; Gaans, van P.; Grotenhuis, J.T.C.; Rijnaarts, H.

    2013-01-01

    Heterogeneity in hydraulic properties of the subsurface is not accounted for in current design calculations of aquifer thermal energy storage (ATES). However, the subsurface is heterogeneous and thus affects the heat distribution around ATES wells. In this paper, the influence of heterogeneity on

  5. Geothermal reservoir simulation of hot sedimentary aquifer system using FEFLOW®

    Science.gov (United States)

    Nur Hidayat, Hardi; Gala Permana, Maximillian

    2017-12-01

    The study presents the simulation of hot sedimentary aquifer for geothermal utilization. Hot sedimentary aquifer (HSA) is a conduction-dominated hydrothermal play type utilizing deep aquifer, which is heated by near normal heat flow. One of the examples of HSA is Bavarian Molasse Basin in South Germany. This system typically uses doublet wells: an injection and production well. The simulation was run for 3650 days of simulation time. The technical feasibility and performance are analysed in regards to the extracted energy from this concept. Several parameters are compared to determine the model performance. Parameters such as reservoir characteristics, temperature information and well information are defined. Several assumptions are also defined to simplify the simulation process. The main results of the simulation are heat period budget or total extracted heat energy, and heat rate budget or heat production rate. Qualitative approaches for sensitivity analysis are conducted by using five parameters in which assigned lower and higher value scenarios.

  6. Geostatistical Interpolation of Particle-Size Curves in Heterogeneous Aquifers

    Science.gov (United States)

    Guadagnini, A.; Menafoglio, A.; Secchi, P.

    2013-12-01

    We address the problem of predicting the spatial field of particle-size curves (PSCs) from measurements associated with soil samples collected at a discrete set of locations within an aquifer system. Proper estimates of the full PSC are relevant to applications related to groundwater hydrology, soil science and geochemistry and aimed at modeling physical and chemical processes occurring in heterogeneous earth systems. Hence, we focus on providing kriging estimates of the entire PSC at unsampled locations. To this end, we treat particle-size curves as cumulative distribution functions, model their densities as functional compositional data and analyze them by embedding these into the Hilbert space of compositional functions endowed with the Aitchison geometry. On this basis, we develop a new geostatistical methodology for the analysis of spatially dependent functional compositional data. Our functional compositional kriging (FCK) approach allows providing predictions at unsampled location of the entire particle-size curve, together with a quantification of the associated uncertainty, by fully exploiting both the functional form of the data and their compositional nature. This is a key advantage of our approach with respect to traditional methodologies, which treat only a set of selected features (e.g., quantiles) of PSCs. Embedding the full PSC into a geostatistical analysis enables one to provide a complete characterization of the spatial distribution of lithotypes in a reservoir, eventually leading to improved predictions of soil hydraulic attributes through pedotransfer functions as well as of soil geochemical parameters which are relevant in sorption/desorption and cation exchange processes. We test our new method on PSCs sampled along a borehole located within an alluvial aquifer near the city of Tuebingen, Germany. The quality of FCK predictions is assessed through leave-one-out cross-validation. A comparison between hydraulic conductivity estimates obtained

  7. Effect of reservoir heterogeneity on air injection performance in a light oil reservoir

    Directory of Open Access Journals (Sweden)

    Hu Jia

    2018-03-01

    Full Text Available Air injection is a good option to development light oil reservoir. As well-known that, reservoir heterogeneity has great effect for various EOR processes. This also applies to air injection. However, oil recovery mechanisms and physical processes for air injection in heterogeneous reservoir with dip angle are still not well understood. The reported setting of reservoir heterogeneous for physical model or simulation model of air injection only simply uses different-layer permeability of porous media. In practice, reservoir heterogeneity follows the principle of geostatistics. How much of contrast in permeability actually challenges the air injection in light oil reservoir? This should be investigated by using layered porous medial settings of the classical Dykstra-Parsons style. Unfortunately, there has been no work addressing this issue for air injection in light oil reservoir. In this paper, Reservoir heterogeneity is quantified based on the use of different reservoir permeability distribution according to classical Dykstra-Parsons coefficients method. The aim of this work is to investigate the effect of reservoir heterogeneity on physical process and production performance of air injection in light oil reservoir through numerical reservoir simulation approach. The basic model is calibrated based on previous study. Total eleven pseudo compounders are included in this model and ten complexity of reactions are proposed to achieve the reaction scheme. Results show that oil recovery factor is decreased with the increasing of reservoir heterogeneity both for air and N2 injection from updip location, which is against the working behavior of air injection from updip location. Reservoir heterogeneity sometimes can act as positive effect to improve sweep efficiency as well as enhance production performance for air injection. High O2 content air injection can benefit oil recovery factor, also lead to early O2 breakthrough in heterogeneous reservoir. Well

  8. Numerical simulation of hydraulic fracture propagation in heterogeneous unconventional reservoir

    Science.gov (United States)

    Liu, Chunting; Li, Mingzhong; Hao, Lihua; Hu, Hang

    2017-10-01

    The distribution of the unconventional reservoir fracture network is influenced by many factors. For the natural fracture undeveloped reservoir, the reservoir heterogeneity, construction factors (fracturing fluid flow rate, fluid viscosity, perforation clusters spacing), horizontal stress difference and stress different coefficient are the main factors that affect the fracture propagation. In the study, first, calculate the reservoir physics mechanics parameters that affect the fracture propagation on the base of the logging date from one actual horizontal well. Set the formation parameters according to the calculation that used to simulate the reservoir heterogeneity. Then, using damage mechanics method, the 2D fracture propagation model with seepage-stress-damage coupling of multi-fracture tight sand reservoir was established. Study the influences of different fracturing ways (open whole fracturing and oriented perforation fracturing) and the position of the perforation clusters to the fracture propagation for heterogeneity reservoir. Analyze the effects of flow rate, fracturing fluid viscosity, perforation clusters spacing, horizontal stress difference and stress different coefficient to fracture morphology for the heterogeneity reservoir and contrast with the homogeneous reservoir. The simulation results show that: the fracture morphology is more complexity formed by oriented perforation crack than open whole crack; For natural fracture undeveloped reservoir, as the flow rate or the fracturing fluid viscosity increases within a certain range, the fracture network tends to be more complexity and the effect is more obvious to heterogeneous reservoir than homogeneous reservoir; As the perforation clusters spacing decreases, the interaction of each fracture will increase, it tends to form more complexity fracture network but with short major fracture; If the horizontal stress difference and stress different coefficient is large (The stress different coefficient >0

  9. Conceptual hydrochemical model of late Pleistocene aquifers at the Samario-Sitio Grande petroleum reservoir, Gulf of Mexico, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Birkle, Peter [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Av. Reforma 113, Col. Palmira, Cuernavaca, Mor., 62490 (Mexico)]. E-mail: birkle@iie.org.mx; Angulo, Maricela [PEMEX - Exploracion y Produccion, Diseno de Explotacion Cactus-Nispero Sitio Grande, Zona Industrial S/N, Reforma, Chiapas (Mexico)

    2005-06-15

    Carbon-14 concentrations between 0.83 and 11.79 pmC of formation water from the Activo Samaria-Sitio Grande petroleum reservoir in SE-Mexico, extracted from 3500 to 4500 m.b.s.l., indicate a common infiltration event of surface water during the late Pleistocene period. Mixing of two components - meteoric water and seawater, previously evaporated at the surface - explain the widespread mineralization (TDI = 15-257 g/L) of Na-Cl and Na-Ca-Cl type reservoir water. Statistical discrimination by clustering and a heterogeneous chemical-isotopic fluid composition indicate the existence of 4 different water types as part of local aquifer systems, which are separated by normal and thrust faults. Tectonic horst and graben structures show an ambiguous, individual hydraulic behaviour - as permeable conduits and/or as impermeable barriers, causing the local limitation of aquifer extent. The recent increase of water production in petroleum wells is not related to the injection of surface water, but the long-term extraction of oil reserves is modifying the original position and flow direction of the reservoir aquifers. The rise of the initial groundwater level reflects the final stage of an exhausted petroleum reservoir with coning effects of underlying aquifer systems. The flexible change towards superior production intervals could represent a feasible technique to avoid the abrupt closure of invaded production wells.

  10. Conceptual hydrochemical model of late Pleistocene aquifers at the Samario-Sitio Grande petroleum reservoir, Gulf of Mexico, Mexico

    International Nuclear Information System (INIS)

    Birkle, Peter; Angulo, Maricela

    2005-01-01

    Carbon-14 concentrations between 0.83 and 11.79 pmC of formation water from the Activo Samaria-Sitio Grande petroleum reservoir in SE-Mexico, extracted from 3500 to 4500 m.b.s.l., indicate a common infiltration event of surface water during the late Pleistocene period. Mixing of two components - meteoric water and seawater, previously evaporated at the surface - explain the widespread mineralization (TDI = 15-257 g/L) of Na-Cl and Na-Ca-Cl type reservoir water. Statistical discrimination by clustering and a heterogeneous chemical-isotopic fluid composition indicate the existence of 4 different water types as part of local aquifer systems, which are separated by normal and thrust faults. Tectonic horst and graben structures show an ambiguous, individual hydraulic behaviour - as permeable conduits and/or as impermeable barriers, causing the local limitation of aquifer extent. The recent increase of water production in petroleum wells is not related to the injection of surface water, but the long-term extraction of oil reserves is modifying the original position and flow direction of the reservoir aquifers. The rise of the initial groundwater level reflects the final stage of an exhausted petroleum reservoir with coning effects of underlying aquifer systems. The flexible change towards superior production intervals could represent a feasible technique to avoid the abrupt closure of invaded production wells

  11. Multiscale Fractal Characterization of Hierarchical Heterogeneity in Sandstone Reservoirs

    Science.gov (United States)

    Liu, Yanfeng; Liu, Yuetian; Sun, Lu; Liu, Jian

    2016-07-01

    Heterogeneities affecting reservoirs often develop at different scales. Previous studies have described these heterogeneities using different parameters depending on their size, and there is no one comprehensive method of reservoir evaluation that considers every scale. This paper introduces a multiscale fractal approach to quantify consistently the hierarchical heterogeneities of sandstone reservoirs. Materials taken from typical depositional pattern and aerial photography are used to represent three main types of sandstone reservoir: turbidite, braided, and meandering river system. Subsequent multiscale fractal dimension analysis using the Bouligand-Minkowski method characterizes well the hierarchical heterogeneity of the sandstone reservoirs. The multiscale fractal dimension provides a curve function that describes the heterogeneity at different scales. The heterogeneity of a reservoir’s internal structure decreases as the observational scale increases. The shape of a deposit’s facies is vital for quantitative determination of the sedimentation type, and thus enhanced oil recovery. Characterization of hierarchical heterogeneity by multiscale fractal dimension can assist reservoir evaluation, geological modeling, and even the design of well patterns.

  12. Delineating alluvial aquifer heterogeneity using resistivity and GPR data.

    Science.gov (United States)

    Bowling, Jerry C; Rodriguez, Antonio B; Harry, Dennis L; Zheng, Chunmiao

    2005-01-01

    Conceptual geological models based on geophysical data can elucidate aquifer architecture and heterogeneity at meter and smaller scales, which can lead to better predictions of preferential flow pathways. The macrodispersion experiment (MADE) site, with >2000 measurements of hydraulic conductivity obtained and three tracer tests conducted, serves as an ideal natural laboratory for examining relationships between subsurface flow characteristics and geophysical attributes in fluvial aquifers. The spatial variation of hydraulic conductivity measurements indicates a large degree of site heterogeneity. To evaluate the usefulness of geophysical methods for better delineating fluvial aquifer heterogeneities and distribution of preferential flow paths, a surface grid of two-dimensional ground penetrating radar (GPR) and direct current (DC) resistivity data were collected. A geological model was developed from these data that delineate four stratigraphic units with distinct electrical and radar properties including (from top to bottom) (1) a meandering fluvial system (MFS); (2) a braided fluvial system (BFS); (3) fine-grained sands; and (4) a clay-rich interval. A paleochannel, inferred by other authors to affect flow, was mapped in the MFS with both DC resistivity and GPR data. The channel is 2 to 4 m deep and, based on resistivity values, is predominantly filled with clay and silt. Comparing previously collected hydraulic conductivity measurements and tracer-plume migration patterns to the geological model indicates that flow primarily occurs in the BFS and that the channel mapped in the MFS has no influence on plume migration patterns.

  13. Stochastic Management of Non-Point Source Contamination: Joint Impact of Aquifer Heterogeneity and Well Characteristics

    Science.gov (United States)

    Henri, C. V.; Harter, T.

    2017-12-01

    Agricultural activities are recognized as the preeminent origin of non-point source (NPS) contamination of water bodies through the leakage of nitrate, salt and agrochemicals. A large fraction of world agricultural activities and therefore NPS contamination occurs over unconsolidated alluvial deposit basins offering soil composition and topography favorable to productive farming. These basins represent also important groundwater reservoirs. The over-exploitation of aquifers coupled with groundwater pollution by agriculture-related NPS contaminant has led to a rapid deterioration of the quality of these groundwater basins. The management of groundwater contamination from NPS is challenged by the inherent complexity of aquifers systems. Contaminant transport dynamics are highly uncertain due to the heterogeneity of hydraulic parameters controlling groundwater flow. Well characteristics are also key uncertain elements affecting pollutant transport and NPS management but quantifying uncertainty in NPS management under these conditions is not well documented. Our work focuses on better understanding the joint impact of aquifer heterogeneity and pumping well characteristics (extraction rate and depth) on (1) the transport of contaminants from NPS and (2) the spatio-temporal extension of the capture zone. To do so, we generate a series of geostatistically equivalent 3D heterogeneous aquifers and simulate the flow and non-reactive solute transport from NPS to extraction wells within a stochastic framework. The propagation of the uncertainty on the hydraulic conductivity field is systematically analyzed. A sensitivity analysis of the impact of extraction well characteristics (pumping rate and screen depth) is also conducted. Results highlight the significant role that heterogeneity and well characteristics plays on management metrics. We finally show that, in case of NPS contamination, the joint impact of regional longitudinal and transverse vertical hydraulic gradients and

  14. Modeling saltwater intrusion in highly heterogeneous coastal aquifers

    Science.gov (United States)

    Safi, Amir; El-Fadel, Mutasem; Doummar, Joanna; Abou Najm, Majdi; Alameddine, Ibrahim

    2016-04-01

    In this study, a 3D variable-density flow and solute transport model SEAWAT was used to examine the impact of macroscopic variation in a soil matrix on widening or narrowing the thickness of the saltwater-freshwater mixing zone. Located along the Eastern Mediterranean (Beirut), the pilot aquifer consists of karstified limestone of Cretaceous age overlain by Upper Tertiary and Quaternary unconsolidated deposits. The model used the advanced pilot-points parameterization coupled with PEST to characterize spatial heterogeneity. Historically simulated water levels were relied upon to reduce potential numerical instabilities induced by insensitive parameters in transient calibration. The latter demonstrated a high degree of heterogeneity in the middle parts of the aquifer and along western coastlines with specification of a high hydraulic conductivity and low storativity in fault networks. The response of the aquifer to seasonal stresses such as climate cycles, pumping rates and recharge rates was manifested as high fluctuations in potentiometric surface due to potential fast flow pathways along faults. The final distribution of saltwater intrusion supports two mechanisms 1) lateral encroachment of recent seawater into the western zone of the aquifer which is of most concern due to high horizontal hydraulic conductivity in the wave direction and 2) upconing in the northwest and southwest of the aquifer due to large vertical hydraulic conductivities that tend to exacerbate the vertical movement of salinity. Acknowledgments This study is part of a program on climate change and seawater intrusion along the Eastern Mediterranean funded by the International Development Research Center (IDRC) of Canada at the American University of Beirut (AUB). Special thanks are extended to Dr. Charlotte Macalister at IDRC for her support and feedback in implementing this program.

  15. SEISMIC DETERMINATION OF RESERVOIR HETEROGENEITY; APPLICATION TO THE CHARACTERIZATION OF HEAVY OIL RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Matthias G. Imhof; James W. Castle

    2003-11-01

    The objective of the project is to examine how seismic and geologic data can be used to improve characterization of small-scale heterogeneity and their parameterization in reservoir models. The study is performed at West Coalinga Field in California. We continued our investigation on the nature of seismic reactions from heterogeneous reservoirs. We began testing our algorithm to infer parameters of object-based reservoir models from seismic data. We began integration of seismic and geologic data to determine the deterministic limits of conventional seismic data interpretation. Lastly, we began integration of seismic and geologic heterogeneity using stochastic models conditioned both on wireline and seismic data.

  16. Characterization of oil and gas reservoir heterogeneity

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    The objective of the cooperative research program is to characterize Alaskan reservoirs in terms of their reserves, physical and chemical properties, geologic configuration and structure, and the development potential. The tasks completed during this period include: (1) geologic reservoir description of Endicott Field; (2) petrographic characterization of core samples taken from selected stratigraphic horizons of the West Sak and Ugnu (Brookian) wells; (3) development of a polydispersed thermodynamic model for predicting asphaltene equilibria and asphaltene precipitation from crude oil-solvent mixtures, and (4) preliminary geologic description of the Milne Point Unit.

  17. The usefulness of multi-well aquifer tests in heterogeneous aquifers

    International Nuclear Information System (INIS)

    Young, S.C.; Benton, D.J.; Herweijer, J.C.; Sims, P.

    1990-01-01

    Three large-scale (100 m) and seven small-scale (3-7 m) multi-well aquifer tests were conducted in a heterogeneous aquifer to determine the transmissivity distribution across a one-hectare test site. Two of the large-scale tests had constant but different rates of discharge; the remaining large-scale test had a discharge that was pulsed at regulated intervals. The small-scale tests were conducted at two well clusters 20 m apart. The program WELTEST was written to analyze the data. By using the methods of non-linear least squares regression analysis and Broyden's method to solve for non-linear extrema, WELTEST automatically determines the best values of transmissivity and the storage coefficient. The test results show that order of magnitude differences in the calculated transmissivities at a well location can be realized by varying the discharge rate at the pumping well, the duration of the aquifer test, and/or the location of the pumping well. The calculated storage coefficients for the tests cover a five-order magnitude range. The data show a definite trend for the storage coefficient to increase with the distance between the pumping and the observation wells. This trend is shown to be related to the orientation of high hydraulic conductivity zones between the pumping and the observation wells. A comparison among single-well aquifer tests, geological investigations and multi-well aquifer tests indicate that the multi-well tests are poorly suited for characterizing a transmissivity field. (Author) (11 refs., 14 figs.)

  18. Characterization of oil and gas reservoir heterogeneity. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Tyler, N.; Barton, M.D.; Bebout, D.G.; Fisher, R.S.; Grigsby, J.D.; Guevara, E.; Holtz, M.; Kerans, C.; Nance, H.S.; Levey, R.A.

    1992-10-01

    Research described In this report addresses the internal architecture of two specific reservoir types: restricted-platform carbonates and fluvial-deltaic sandstones. Together, these two reservoir types contain more than two-thirds of the unrecovered mobile oil remaining ill Texas. The approach followed in this study was to develop a strong understanding of the styles of heterogeneity of these reservoir types based on a detailed outcrop description and a translation of these findings into optimized recovery strategies in select subsurface analogs. Research targeted Grayburg Formation restricted-platform carbonate outcrops along the Algerita Escarpment and In Stone Canyon In southeastern New Mexico and Ferron deltaic sandstones in central Utah as analogs for the North Foster (Grayburg) and Lake Creek (Wilcox) units, respectively. In both settings, sequence-stratigraphic style profoundly influenced between-well architectural fabric and permeability structure. It is concluded that reservoirs of different depositional origins can therefore be categorized Into a ``heterogeneity matrix`` based on varying intensity of vertical and lateral heterogeneity. The utility of the matrix is that it allows prediction of the nature and location of remaining mobile oil. Highly stratified reservoirs such as the Grayburg, for example, will contain a large proportion of vertically bypassed oil; thus, an appropriate recovery strategy will be waterflood optimization and profile modification. Laterally heterogeneous reservoirs such as deltaic distributary systems would benefit from targeted infill drilling (possibly with horizontal wells) and improved areal sweep efficiency. Potential for advanced recovery of remaining mobile oil through heterogeneity-based advanced secondary recovery strategies In Texas is projected to be an Incremental 16 Bbbl. In the Lower 48 States this target may be as much as 45 Bbbl at low to moderate oil prices over the near- to mid-term.

  19. TDT monitors gas saturation in heterogeneous reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, G.M.; Al-Awad, M.N.J. [King Saud Univ., Riyadh (Saudi Arabia)

    1998-05-25

    Thermal decay time (TDT) logs were used for determining the gas/oil contact in wells in the Zeit Bay field in Egypt. Gas/oil contact in the field was revised using the results from the model that was developed. The analysis followed the Polyachenko model of functional relationship between count rates and gas saturation. Several crossplots were made for the same range of porosity and connate water saturation. These crossplots included: formation capture cross section; total selected near detector counts; total selected far detector counts; capture cross section of the borehole; and inelastic far detector counts. Each crossplot gave a definite diagnostic shape around the depth of the gas/oil contact. By using these crossplots, it is possible to calculate gas saturation from a stand-alone run. The model was validated by RFT (reservoir formation tester) and open hole log data from infill wells. Also, the analysis was successfully applied in wells without an ambiguous gas/oil contact.

  20. Upscaling of permeability heterogeneities in reservoir rocks; an integrated approach

    NARCIS (Netherlands)

    Mikes, D.

    2002-01-01

    This thesis presents a hierarchical and geologically constrained deterministic approach to incorporate small-scale heterogeneities into reservoir flow simulators. We use a hierarchical structure to encompass all scales from laminae to an entire depositional system. For the geological models under

  1. The influence of reservoir heterogeneities on geothermal doublet performance

    NARCIS (Netherlands)

    Doddema, Leon

    2012-01-01

    SUMMARY The current main problem with deep geothermal energy in the Netherlands is the uncertainty in terms of attainable flow rate and life time. The goal of this research is therefore modeling a geothermal doublet in a heterogeneous reservoir, using a

  2. Saltwater Intrusion Simulation in Heterogeneous Aquifer Using Lattice Boltzmann Method

    Science.gov (United States)

    Servan-Camas, B.; Tsai, F. T.

    2006-12-01

    This study develops a saltwater intrusion simulation model using a lattice Boltzmann method (LBM) in a two- dimensional coastal confined aquifer. The saltwater intrusion phenomenon is described by density-varied groundwater flow and mass transport equations, where a freshwater-saltwater mixing zone is considered. Although primarily developed using the mesoscopic approach to solve macroscopic fluid dynamic problems (e.g. Navier-Stoke equation), LBM is able to be adopted to solve physical-based diffusion-type governing equations as for the groundwater flow and mass transport equations. The challenge of using LBM in saltwater intrusion modeling is to recover hydraulic conductivity heterogeneity. In this study, the Darcy equation and the advection-dispersion equation (ADE) are recovered in the lattice Boltzmann modeling. Specifically, the hydraulic conductivity heterogeneity is represented by the speed of sound in LBM. Under the consideration on the steady-state groundwater flow due to low storativity, in each time step the flow problem is modified to be a Poisson equation and solved by LBM. Nevertheless, the groundwater flow is still a time-marching problem with spatial-temporal variation in salinity concentration as well as density. The Henry problem is used to compare the LBM results against the Henry analytic solution and SUTRA result. Also, we show that LBM is capable of handling the Dirichlet, Neumann, and Cauchy concentration boundary conditions at the sea side. Finally, we compare the saltwater intrusion results using LBM in the Henry problem when heterogeneous hydraulic conductivity is considered.

  3. Field study of macrodispersion in a heterogeneous aquifer. I

    International Nuclear Information System (INIS)

    Boggs, J.M.; Young, S.C.; Waldrop, W.R.; Gelhar, L.W.; Adams, E.E.; Rehfeldt, K.R.

    1990-01-01

    A large-scale natural gradient tracer experiment has been conducted at a field site located at Columbus Air Force Base in northeastern Mississippi. The alluvial aquifer at the test site is composed of lenticular deposits of sand, gravel, silt and clay, and is quite heterogeneous with respect to its hydraulic properties. Ten cubic meters of a solution containing bromide and three organic tracers (pentafluorobenzoic acid, o-trifluoromethylbenzoic acid, and 2,6-difluorobenzoic acid) were injected into the aquifer at a uniform rate over a period of two days. The tracer plume was subsequently monitored in three dimensions over a 20-month period using a network of 258 multilevel sampling wells. The tracer concentration distribution of the plume at the conclusion of the experiment was highly asymmetric in the longitudinal direction. The peak tracer concentration was located only 7 m from the injection point, while the advancing side of the plume extended downgradient a distance of more than 260 m. The extreme skewness of the plume was caused by large scale spatial variations in the mean groundwater velocity along the plume travel path produced by the approximate two order-of-magnitude increase in the mean hydraulic conductivity between the near-field and far-field regions of the experimental site. The tracer mass balance during the experiment showed a declining trend between sampling events with approximately 50 percent of the injected tracer mass unaccounted for at the end of the experiment. Laboratory column experiments indicated that approximately 20 percent of the tracer mass was adsorbed to the aquifer matrix. The remaining 30 percent of the missing tracer mass was attributed to incomplete sampling coverage of the plume, particularly on the advancing side, and to a sampling bias produced by the multilevel samplers. (Author) (17 refs., 3 tabs., 11 figs.)

  4. Characterizing Heterogeneity in Infiltration Rates During Managed Aquifer Recharge.

    Science.gov (United States)

    Mawer, Chloe; Parsekian, Andrew; Pidlisecky, Adam; Knight, Rosemary

    2016-11-01

    Infiltration rate is the key parameter that describes how water moves from the surface into a groundwater aquifer during managed aquifer recharge (MAR). Characterization of infiltration rate heterogeneity in space and time is valuable information for MAR system operation. In this study, we utilized fiber optic distributed temperature sensing (FO-DTS) observations and the phase shift of the diurnal temperature signal between two vertically co-located fiber optic cables to characterize infiltration rate spatially and temporally in a MAR basin. The FO-DTS measurements revealed spatial heterogeneity of infiltration rate: approximately 78% of the recharge water infiltrated through 50% of the pond bottom on average. We also introduced a metric for quantifying how the infiltration rate in a recharge pond changes over time, which enables FO-DTS to be used as a method for monitoring MAR and informing maintenance decisions. By monitoring this metric, we found high-spatial variability in how rapidly infiltration rate changed during the test period. We attributed this variability to biological pore clogging and found a relationship between high initial infiltration rate and the most rapid pore clogging. We found a strong relationship (R 2  = 0.8) between observed maximum infiltration rates and electrical resistivity measurements from electrical resistivity tomography data taken in the same basin when dry. This result shows that the combined acquisition of DTS and ERT data can improve the design and operation of a MAR pond significantly by providing the critical information needed about spatial variability in parameters controlling infiltration rates. © 2016, National Ground Water Association.

  5. Using solute and heat tracers for aquifer characterization in a strongly heterogeneous alluvial aquifer

    Science.gov (United States)

    Sarris, Theo S.; Close, Murray; Abraham, Phillip

    2018-03-01

    A test using Rhodamine WT and heat as tracers, conducted over a 78 day period in a strongly heterogeneous alluvial aquifer, was used to evaluate the utility of the combined observation dataset for aquifer characterization. A highly parameterized model was inverted, with concentration and temperature time-series as calibration targets. Groundwater heads recorded during the experiment were boundary dependent and were ignored during the inversion process. The inverted model produced a high resolution depiction of the hydraulic conductivity and porosity fields. Statistical properties of these fields are in very good agreement with estimates from previous studies at the site. Spatially distributed sensitivity analysis suggests that both solute and heat transport were most sensitive to the hydraulic conductivity and porosity fields and less sensitive to dispersivity and thermal distribution factor, with sensitivity to porosity greatly reducing outside the monitored area. The issues of model over-parameterization and non-uniqueness are addressed through identifiability analysis. Longitudinal dispersivity and thermal distribution factor are highly identifiable, however spatially distributed parameters are only identifiable near the injection point. Temperature related density effects became observable for both heat and solute, as the temperature anomaly increased above 12 degrees centigrade, and affected down gradient propagation. Finally we demonstrate that high frequency and spatially dense temperature data cannot inform a dual porosity model in the absence of frequent solute concentration measurements.

  6. Field study of macrodispersion in a heterogeneous aquifer. 2

    International Nuclear Information System (INIS)

    Boggs, J.M.; Rehfeldt, K.R.

    1990-01-01

    Observations of the spatial variability of the hydraulic conductivity field at the site of a large-scale natural gradient tracer experiment located at Columbus Air Force Base in Mississippi are presented. Direct measurements of hydraulic conductivity of the heterogeneous alluvial aquifer at the site were made using a variety of methods including aquifer tests, borehole flowmeter logging, double-packer tests, slug tests, and a newly developed laboratory permeameter to test undisturbed soil cores. The borehole flowmeter method was shown to be the most effective method for measuring conductivity variability. Estimates of the log hydraulic conductivity variance (σ 2 lnL ) and the horizontal and vertical correlation sales, (λ h and λ v ) of 4.5, 12 m, and 1.5 m, respectively, were calculated assuming second order stationarity of the conductivity field. Large-scale spatial variations in the mean groundwater velocity indicated by the natural gradient tracer experiment, which were shown to be a direct result of contrasts in the mean hydraulic conductivity along the plume pathway, strongly suggested the presence of a conductivity trend. The measured hydraulic conductivity data were subsequently detrended using least-squares regression to remove three-dimensional polynomials. The third-order polynomial was judged the best representation of the conductivity drift based on its overall compatibility with the groundwater flow field inferred from the tracer plume observations. Significantly lower estimates for σ 2 lnK , λ h , and λ v of 2.8, 5.3 m, and 0.7 m, respectively, were obtained from the third-order log conductivity residuals. The experience with the borehole flowmeter technique shows the feasibility of observing the statistical parameters of the hydraulic conductivity variability required for stochastic models of macrodispersion. (Author) (20 refs., 3 figs., 10 tabs.)

  7. Stochastic analysis of the hydraulic conductivity estimated for a heterogeneous aquifer via numerical modelling

    Directory of Open Access Journals (Sweden)

    C. Lu

    2015-05-01

    Full Text Available The paper aims to evaluate the impacts of the average hydraulic conductivity of the heterogeneous aquifer on the estimated hydraulic conductivity using the observations from pumping tests. The results of aquifer tests conducted at a karst aquifer are first introduced. A MODFLOW groundwater flow model was developed to perform numerical pumping tests, and the heterogeneous hydraulic conductivity (K field was generated using the Monte Carlo method. The K was estimated by the Theis solution for an unconfined aquifer. The effective hydraulic conductivity (Ke was calculated to represent the hydraulic conductivity of a heterogeneous aquifer. The results of numerical simulations demonstrate that Ke increase with the mean of hydraulic conductivity (EK, and decrease with the coefficient of variation of the hydraulic conductivity (Cv. The impact of spatial variability of K on the estimated Ke at two observation wells with smaller EK is less significant compared to the cases with larger EK.

  8. Modelling and monitoring of Aquifer Thermal Energy Storage : impacts of soil heterogeneity, thermal interference and bioremediation

    NARCIS (Netherlands)

    Sommer, W.T.

    2015-01-01

    Modelling and monitoring of Aquifer Thermal Energy Storage

    Impacts of heterogeneity, thermal interference and bioremediation

    Wijbrand Sommer
    PhD thesis, Wageningen University, Wageningen, NL (2015)
    ISBN 978-94-6257-294-2

    Abstract

    Aquifer

  9. Modelling and monitoring of Aquifer Thermal Energy Storage : impacts of soil heterogeneity, thermal interference and bioremediation

    NARCIS (Netherlands)

    Sommer, W.T.

    2015-01-01

    Modelling and monitoring of Aquifer Thermal Energy Storage Impacts of heterogeneity, thermal interference and bioremediation Wijbrand Sommer
    PhD thesis, Wageningen University, Wageningen, NL (2015)
    ISBN 978-94-6257-294-2 Abstract Aquifer thermal energy storage (ATES) is

  10. Prediction of Gas Injection Performance for Heterogeneous Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Blunt, Martin J.; Orr, Jr., Franklin M.

    1999-12-20

    This report describes research carried out in the Department of Petroleum Engineering at Stanford University from September 1998 - September 1998 under the third year of a three-year Department of Energy (DOE) grant on the ''Prediction of Gas Injection Performance for Heterogeneous Reservoirs''. The research effort is an integrated study of the factors affecting gas injection, from the pore scale to the field scale, and involves theoretical analysis, laboratory experiments and numerical simulation. The research is divided into four main areas: (1) Pore scale modeling of three-phase flow in porous media; (2) Laboratory experiments and analysis of factors influencing gas injection performance at the core scale with an emphasis on the fundamentals of three-phase flow; (3) Benchmark simulations of gas injection at the field scale; and (4) Development of streamline-based reservoir simulator.

  11. SEISMIC DETERMINATION OF RESERVOIR HETEROGENEITY: APPLICATION TO THE CHARACTERIZATION OF HEAVY OIL RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Matthias G. Imhof; James W. Castle

    2005-02-01

    The objective of the project was to examine how seismic and geologic data can be used to improve characterization of small-scale heterogeneity and their parameterization in reservoir models. The study focused on West Coalinga Field in California. The project initially attempted to build reservoir models based on different geologic and geophysical data independently using different tools, then to compare the results, and ultimately to integrate them all. We learned, however, that this strategy was impractical. The different data and tools need to be integrated from the beginning because they are all interrelated. This report describes a new approach to geostatistical modeling and presents an integration of geology and geophysics to explain the formation of the complex Coalinga reservoir.

  12. PREDICTION OF GAS INJECTION PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Martin J. Blunt; Franklin M. Orr Jr

    2000-06-01

    This final report describes research carried out in the Department of Petroleum Engineering at Stanford University from September 1996--May 2000 under a three-year grant from the Department of Energy on the ''Prediction of Gas Injection Performance for Heterogeneous Reservoirs''. The advances from the research include: new tools for streamline-based simulation including the effects of gravity, changing well conditions, and compositional displacements; analytical solutions to 1D compositional displacements which can speed-up gas injection simulation still further; and modeling and experiments that delineate the physics that is unique to three-phase flow.

  13. IMPROVING CO2 EFFICIENCY FOR RECOVERING OIL IN HETEROGENEOUS RESERVOIRS

    International Nuclear Information System (INIS)

    Reid B. Grigg; Robert K. Svec; Zheng-Wen Zeng; Liu Yi; Baojun Bai

    2004-01-01

    A three-year contract for the project, DOE Contract No. DE-FG26-01BC15364, ''Improving CO 2 Efficiency for Recovering Oil in Heterogeneous Reservoirs'', was started on September 28, 2001. This project examines three major areas in which CO 2 flooding can be improved: fluid and matrix interactions, conformance control/sweep efficiency, and reservoir simulation for improved oil recovery. The project has received a one-year, no-cost extension to September 27, 2005. During this extra time additional deliverables will be (1) the version of MASTER that has been debugged and a foam option added for CO 2 mobility control and (2) adsorption/desorption data on pure component minerals common in reservoir rock that will be used to improve predictions of chemical loss to adsorption in reservoirs. This report discusses the activity during the six-month period covering October 1, 2003 through March 31, 2004 that comprises the first and second fiscal quarters of the project's third year. During this period of the project several areas have advanced: reservoir fluid/rock interactions and their relationships to changing injectivity, and surfactant adsorption on quarried core and pure component granules, foam stability, and high flow rate effects. Presentations and papers included: a papers covered in a previous report was presented at the fall SPE ATCE in Denver in October 2003, a presentation at the Southwest ACS meeting in Oklahoma City, presentation on CO 2 flood basic behavior at the Midland Annual CO 2 Conference December 2003; two papers prepared for the biannual SPE/DOE Symposium on IOR, Tulsa, April 2004; one paper accepted for the fall 2004 SPE ATCE in Houston; and a paper submitted to an international journal Journal of Colloid and Interface Science which is being revised after peer review

  14. STRUCTURAL HETEROGENEITIES AND PALEO FLUID FLOW IN AN ANALOG SANDSTONE RESERVOIR 2001-2004

    International Nuclear Information System (INIS)

    Pollard, David; Aydin, Atilla

    2005-01-01

    Fractures and faults are brittle structural heterogeneities that can act both as conduits and barriers with respect to fluid flow in rock. This range in the hydraulic effects of fractures and faults greatly complicates the challenges faced by geoscientists working on important problems: from groundwater aquifer and hydrocarbon reservoir management, to subsurface contaminant fate and transport, to underground nuclear waste isolation, to the subsurface sequestration of CO2 produced during fossil-fuel combustion. The research performed under DOE grant DE-FG03-94ER14462 aimed to address these challenges by laying a solid foundation, based on detailed geological mapping, laboratory experiments, and physical process modeling, on which to build our interpretive and predictive capabilities regarding the structure, patterns, and fluid flow properties of fractures and faults in sandstone reservoirs. The material in this final technical report focuses on the period of the investigation from July 1, 2001 to October 31, 2004. The Aztec Sandstone at the Valley of Fire, Nevada, provides an unusually rich natural laboratory in which exposures of joints, shear deformation bands, compaction bands and faults at scales ranging from centimeters to kilometers can be studied in an analog for sandstone aquifers and reservoirs. The suite of structures there has been documented and studied in detail using a combination of low-altitude aerial photography, outcrop-scale mapping and advanced computational analysis. In addition, chemical alteration patterns indicative of multiple paleo fluid flow events have been mapped at outcrop, local and regional scales. The Valley of Fire region has experienced multiple episodes of fluid flow and this is readily evident in the vibrant patterns of chemical alteration from which the Valley of Fire derives its name. We have successfully integrated detailed field and petrographic observation and analysis, process-based mechanical modeling, and numerical

  15. STRUCTURAL HETEROGENEITIES AND PALEO FLUID FLOW IN AN ANALOG SANDSTONE RESERVOIR 2001-2004

    Energy Technology Data Exchange (ETDEWEB)

    Pollard, David; Aydin, Atilla

    2005-02-22

    Fractures and faults are brittle structural heterogeneities that can act both as conduits and barriers with respect to fluid flow in rock. This range in the hydraulic effects of fractures and faults greatly complicates the challenges faced by geoscientists working on important problems: from groundwater aquifer and hydrocarbon reservoir management, to subsurface contaminant fate and transport, to underground nuclear waste isolation, to the subsurface sequestration of CO2 produced during fossil-fuel combustion. The research performed under DOE grant DE-FG03-94ER14462 aimed to address these challenges by laying a solid foundation, based on detailed geological mapping, laboratory experiments, and physical process modeling, on which to build our interpretive and predictive capabilities regarding the structure, patterns, and fluid flow properties of fractures and faults in sandstone reservoirs. The material in this final technical report focuses on the period of the investigation from July 1, 2001 to October 31, 2004. The Aztec Sandstone at the Valley of Fire, Nevada, provides an unusually rich natural laboratory in which exposures of joints, shear deformation bands, compaction bands and faults at scales ranging from centimeters to kilometers can be studied in an analog for sandstone aquifers and reservoirs. The suite of structures there has been documented and studied in detail using a combination of low-altitude aerial photography, outcrop-scale mapping and advanced computational analysis. In addition, chemical alteration patterns indicative of multiple paleo fluid flow events have been mapped at outcrop, local and regional scales. The Valley of Fire region has experienced multiple episodes of fluid flow and this is readily evident in the vibrant patterns of chemical alteration from which the Valley of Fire derives its name. We have successfully integrated detailed field and petrographic observation and analysis, process-based mechanical modeling, and numerical

  16. IMPROVING CO2 EFFICIENCY FOR RECOVERING OIL IN HETEROGENEOUS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Reid B. Grigg

    2003-10-31

    The second annual report of ''Improving CO{sub 2} Efficiency for Recovery Oil in Heterogeneous Reservoirs'' presents results of laboratory studies with related analytical models for improved oil recovery. All studies have been undertaken with the intention to optimize utilization and extend the practice of CO{sub 2} flooding to a wider range of reservoirs. Many items presented in this report are applicable to other interest areas: e.g. gas injection and production, greenhouse gas sequestration, chemical flooding, reservoir damage, etc. Major areas of studies include reduction of CO{sub 2} mobility to improve conformance, determining and understanding injectivity changes in particular injectivity loses, and modeling process mechanisms determined in the first two areas. Interfacial tension (IFT) between a high-pressure, high-temperature CO{sub 2} and brine/surfactant and foam stability are used to assess and screen surfactant systems. In this work the effects of salinity, pressure, temperature, surfactant concentration, and the presence of oil on IFT and CO{sub 2} foam stability were determined on the surfactant (CD1045{trademark}). Temperature, pressure, and surfactant concentration effected both IFT and foam stability while oil destabilized the foam, but did not destroy it. Calcium lignosulfonate (CLS) can be used as a sacrificial and an enhancing agent. This work indicates that on Berea sandstone CLS concentration, brine salinity, and temperature are dominant affects on both adsorption and desorption and that adsorption is not totally reversible. Additionally, CLS adsorption was tested on five minerals common to oil reservoirs; it was found that CLS concentration, salinity, temperature, and mineral type had significant effects on adsorption. The adsorption density from most to least was: bentonite > kaolinite > dolomite > calcite > silica. This work demonstrates the extent of dissolution and precipitation from co-injection of CO{sub 2} and

  17. Estimating transmissivity from single-well pumping tests in heterogeneous aquifers

    Science.gov (United States)

    Pechstein, Armin; Attinger, Sabine; Krieg, Ronald; Copty, Nadim K.

    2016-01-01

    Although aquifers are naturally heterogeneous, the interpretation of pumping tests is commonly performed under the assumption of aquifer homogeneity. This yields interpreted hydraulic parameters averaged over a domain of uncertain extent which disguises their relation to the underlying heterogeneity. In this study, we numerically investigate the sensitivity of the transient drawdown at the pumping well, to nonuniform distributions of transmissivity in confined aquifers. Frechet kernels and their time derivative are used to estimate two spatially averaged transmissivities, denoted the equivalent and interpreted transmissivity, Teq and Tin, respectively, for the case of single-well pumping tests. Interrelating Teq and Tin is achieved by modeling Tin in terms of a distance dependent, radially heterogeneous field. In weakly heterogeneous aquifers, Teq approximates TPW, the local transmissivity at the pumped well. With increasing degree of heterogeneity, Teq deviates from TPW as pumping propagates. Tin starts at TPW, approaching the spatial geometric mean of transmissivity during late pumping times. Limits of the proposed spatial weighting functions are investigated by treating the interpreted storativity, Sest, as an indicator for flow connectivity. It is shown numerically that the spatial weights for Teq and Tin agree well to the underlying heterogeneity if . Finally, implications for applying the concepts of Teq and Tin to heterogeneous domains, and, for real world applications are discussed. It is found that time-dependent spatial averages of Tin agree well with estimates of the interpreted transmissivity from the Continuous-Derivation method.

  18. Prediction of Gas Injection Performance for Heterogeneous Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Blunt, Michael J.; Orr, Franklin M.

    1999-05-26

    This report describes research carried out in the Department of Petroleum Engineering at Stanford University from September 1996 - September 1997 under the first year of a three-year Department of Energy grant on the Prediction of Gas Injection Performance for Heterogeneous Reservoirs. The research effort is an integrated study of the factors affecting gas injection, from the pore scale to the field scale, and involves theoretical analysis, laboratory experiments and numerical simulation. The original proposal described research in four main areas; (1) Pore scale modeling of three phase flow in porous media; (2) Laboratory experiments and analysis of factors influencing gas injection performance at the core scale with an emphasis on the fundamentals of three phase flow; (3) Benchmark simulations of gas injection at the field scale; and (4) Development of streamline-based reservoir simulator. Each stage of the research is planned to provide input and insight into the next stage, such that at the end we should have an integrated understanding of the key factors affecting field scale displacements.

  19. Prediction of Gas Injection Performance for Heterogeneous Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Blunt, Martin J.; Orr, Franklin M.

    1999-05-17

    This report describes research carried out in the Department of Petroleum Engineering at Stanford University from September 1997 - September 1998 under the second year of a three-year grant from the Department of Energy on the "Prediction of Gas Injection Performance for Heterogeneous Reservoirs." The research effort is an integrated study of the factors affecting gas injection, from the pore scale to the field scale, and involves theoretical analysis, laboratory experiments, and numerical simulation. The original proposal described research in four areas: (1) Pore scale modeling of three phase flow in porous media; (2) Laboratory experiments and analysis of factors influencing gas injection performance at the core scale with an emphasis on the fundamentals of three phase flow; (3) Benchmark simulations of gas injection at the field scale; and (4) Development of streamline-based reservoir simulator. Each state of the research is planned to provide input and insight into the next stage, such that at the end we should have an integrated understanding of the key factors affecting field scale displacements.

  20. Multiple recharge processes to heterogeneous Mediterranean coastal aquifers and implications on recharge rates evolution in time

    Science.gov (United States)

    Santoni, S.; Huneau, F.; Garel, E.; Celle-Jeanton, H.

    2018-04-01

    Climate change is nowadays widely considered to have major effects on groundwater resources. Climatic projections suggest a global increase in evaporation and higher frequency of strong rainfall events especially in Mediterranean context. Since evaporation is synonym of low recharge conditions whereas strong rainfall events are more favourable to recharge in heterogeneous subsurface contexts, a lack of knowledge remains then on the real ongoing and future drinking groundwater supply availability at aquifers scale. Due to low recharge potential and high inter-annual climate variability, this issue is strategic for the Mediterranean hydrosystems. This is especially the case for coastal aquifers because they are exposed to seawater intrusion, sea-level rise and overpumping risks. In this context, recharge processes and rates were investigated in a Mediterranean coastal aquifer with subsurface heterogeneity located in Southern Corsica (France). Aquifer recharge rates from combining ten physical and chemical methods were computed. In addition, hydrochemical and isotopic investigations were carried out through a monthly two years monitoring combining major ions and stable isotopes of water in rain, runoff and groundwater. Diffuse, focused, lateral mountain system and irrigation recharge processes were identified and characterized. A predominant focused recharge conditioned by subsurface heterogeneity is evidenced in agreement with variable but highly favourable recharge rates. The fast water transfer from the surface to the aquifer implied by this recharge process suggests less evaporation, which means higher groundwater renewal and availability in such Mediterranean coastal aquifers.

  1. A newly developed borehole flowmeter technology for heterogeneous aquifers

    International Nuclear Information System (INIS)

    Young, S.C.

    1990-01-01

    Extensive borehole flowmeter tests were performed at 37 fully-screened wells on a one-hectare test site to characterize the three-dimensional hydraulic conductivity field of an alluvial aquifer with a σ lnK of 4.7. During the site investigations, several major advancements with respect to borehole flowmeter technology were developed. The milestones included: (1) the development of a field-durable electromagnetic borehole flowmeter with a lower detection limit of 0.1 l/min; (2) the realization of the importance of the pumping rate with respect to the calculated value for the depth-averaged hydraulic conductivity; and (3) an evaluation of alternative methods for calculating the depth-averaged hydraulic conductivity. The predicted three-dimensional hydraulic conductivity field was compared to the results of 10 small-scale (3 to 7 m) tracer tests, information about the depositional history of the aquifer, and the results of three large-scale aquifer tests. The hydraulic conductivity data predict the major features of the tracer breakthrough curves, maps the outline of a former river meander in an aerial photograph, and leads to a geometric mean consistent with the average hydraulic conductivity of the aquifer. (Author) (14 refs., 15 figs., 2 tabs.)

  2. Experimental and numerical study for seawater intrusion remediation in heterogeneous coastal aquifer.

    Science.gov (United States)

    Ahmed, Abdelkader T

    2017-08-01

    The contamination of fresh groundwater by saltwater intrusion (SWI) becomes a worldwide alarming problem, which threatens all countries depending on groundwater abstraction from coastal areas. Various control and treatment strategies have been suggested to prevent SWI. The construction of subsurface physical barriers is one of the most practical implementation methods to prevent SWI. In this work, the use of subsurface dam as a remediation and protection tool was investigated in a heterogeneous aquifer via lab scale experiments and numerical simulation. The experiments depended on a novel automated imaged analysis method for SWI measurements. Glass beads of different grain sizes were used in sandbox experiments. The simulation works adopted the SEAWAT code for validation of the experimental results and making numerical sensitivity analyses for affecting parameters. Results proved the significant impact of using sub water dams with heterogonous aquifers. The remediation impacts of the dam was captured clearly in preventing and backwashing of the existed SWI. The results revealed also that the heterogeneous aquifers with high permeability in the bottom boundary behave closer to the homogenous aquifers in SWI than those having low hydraulic conductivity in the bottom. Sensitivity analyses results showed that the closer dam to seawater boundary led to the quicker and more effective backwashing process. Results exhibited also that the dam height with 50% of the aquifer dam has the ability to hold the seawater so long as the hydraulic gradient is high and dams with 67% of aquifer height prevent the saltwater intrusion completely. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Estimating the Spatial Extent of Unsaturated Zones in Heterogeneous River-Aquifer Systems

    Science.gov (United States)

    Schilling, Oliver S.; Irvine, Dylan J.; Hendricks Franssen, Harrie-Jan; Brunner, Philip

    2017-12-01

    The presence of unsaturated zones at the river-aquifer interface has large implications on numerous hydraulic and chemical processes. However, the hydrological and geological controls that influence the development of unsaturated zones have so far only been analyzed with simplified conceptualizations of flow processes, or homogeneous conceptualizations of the hydraulic conductivity in either the aquifer or the riverbed. We systematically investigated the influence of heterogeneous structures in both the riverbed and the aquifer on the development of unsaturated zones. A stochastic 1-D criterion that takes both riverbed and aquifer heterogeneity into account was developed using a Monte Carlo sampling technique. The approach allows the reliable estimation of the upper bound of the spatial extent of unsaturated areas underneath a riverbed. Through systematic numerical modeling experiments, we furthermore show that horizontal capillary forces can reduce the spatial extent of unsaturated zones under clogged areas. This analysis shows how the spatial structure of clogging layers and aquifers influence the propensity for unsaturated zones to develop: In riverbeds where clogged areas are made up of many small, spatially disconnected patches with a diameter in the order of 1 m, unsaturated areas are less likely to develop compared to riverbeds where large clogged areas exist adjacent to unclogged areas. A combination of the stochastic 1-D criterion with an analysis of the spatial structure of the clogging layers and the potential for resaturation can help develop an appropriate conceptual model and inform the choice of a suitable numerical simulator for river-aquifer systems.

  4. Aquifer heterogeneity characterization with oscillatory pumping: Sensitivity analysis and imaging potential

    Science.gov (United States)

    Cardiff, M.; Bakhos, T.; Kitanidis, P. K.; Barrash, W.

    2013-09-01

    Periodic pumping tests, in which a fluid is extracted during half a period, then reinjected, have been used historically to estimate effective aquifer properties. In this work, we suggest a modified approach to periodic pumping test analysis in which one uses several periodic pumping signals of different frequencies as stimulation, and responses are analyzed through inverse modeling using a "steady-periodic" model formulation. We refer to this strategy as multifrequency oscillatory hydraulic imaging. Oscillating pumping tests have several advantages that have been noted, including no net water extraction during testing and robust signal measurement through signal processing. Through numerical experiments, we demonstrate additional distinct advantages that multifrequency stimulations have, including: (1) drastically reduced computational cost through use of a steady-periodic numerical model and (2) full utilization of the aquifer heterogeneity information provided by responses at different frequencies. We first perform fully transient numerical modeling for heterogeneous aquifers and show that equivalent results are obtained using a faster steady-periodic heterogeneous numerical model of the wave phasor. The sensitivities of observed signal response to aquifer heterogeneities are derived using an adjoint state-based approach, which shows that different frequency stimulations provide complementary information. Finally, we present an example 2-D application in which sinusoidal signals at multiple frequencies are used as a data source and are inverted to obtain estimates of aquifer heterogeneity. These analyses show the different heterogeneity information that can be obtained from different stimulation frequencies, and that data from several sinusoidal pumping tests can be rapidly inverted using the steady-periodic framework.

  5. Inverse Modeling of Geological Heterogeneity for Goal-Oriented Aquifer Characterization

    OpenAIRE

    Savoy, Heather Marie

    2017-01-01

    Characterizing the spatial heterogeneity of aquifer properties, particularly hydraulic conductivity, is paramount in groundwater modeling when the transport and fate of contaminants need to be predicted. The field of geostatistics has focused on describing this heterogeneity with spatial random functions. The field of stochastic hydrogeology uses these functions to incorporate uncertainty about the subsurface in groundwater modeling predictions. Bayesian inference can update prior knowledge a...

  6. Experimental Study of Movement and Distribution of Dense Organic Contaminants in Heterogeneous Aquifers

    DEFF Research Database (Denmark)

    Illangasekare, Tissa H.; Ramsey Jr., James L.; Jensen, Karsten Høgh

    1995-01-01

    An experimental study of the migration of denser-than-water nonaqueous phase organic contaminants through heterogeneous porous media was carried out. The purpose of the study was to observe the flow and record the migration of the contaminant to gain a fundamental insight into the way aquifer...

  7. Influence of physical and chemical aquifer heterogeneity on nitrate reduction processes by numerical simulations

    Science.gov (United States)

    Kalbacher, T.; Jang, E.; He, W.; Savoy, H.; Schueth, C.; Kolditz, O.

    2015-12-01

    Nitrate reduction reactions, as one of the most important redox reactions in a subsurface system, are strongly influenced by various heterogeneity factors which influence transport of chemical species and spatial distribution of redox substances and consequently have an effect on overall nitrate reduction capacity. In this presented work, the influence of two heterogeneity factors, spatially heterogeneity of hydrological parameters versus spatial heterogeneity of geochemical reactive substances distribution, are discussed with a focus on nitrate transport and redox transformation processes. For this purpose, a coupling interface OGS#IPhreeqc is employed. This code combines Finite-Element groundwater flow and multi-species transport code of OpenGeoSys (OGS) with the IPhreeqc module of open source geochemical solver PHREEQC. The resulting coupled model is applied for simulation of nitrate reduction processes with a series of hypothetical aquifer systems, built using exponentially-correlated log-normal distributed hydraulic conductivity and reactive substances. The spatially heterogeneous aquifer system is realized by a RandomFields package using a statistical program R. Results show that the heterogeneous hydraulics conductivity field has larger impact on nitrate reduction capacity than heterogeneous reactive substances distribution. Moreover, nitrate reduction capacity can be increased by enhanced mixing in heterogeneous hydraulic conductivity field however its overall reduction capacity has gradually decreased as a degree of heterogeneity has increased since accessibility of the chemical species by the reactive substances may be limited. These results support that appropriate characterization of the variance of hydraulic conductivity within the aquifer is important to predict contaminant fate and transport and quantify the impact of uncertainty on numerical groundwater simulation.

  8. Geochemical Impacts of Leaking CO2 from Subsurface Storage Reservoirs to Unconfined and Confined Aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Qafoku, Nikolla; Brown, Christopher F.; Wang, Guohui; Sullivan, E. C.; Lawter, Amanda R.; Harvey, Omar R.; Bowden, Mark

    2013-04-15

    Experimental research work has been conducted and is undergoing at Pacific Northwest National Laboratory (PNNL) to address a variety of scientific issues related with the potential leaks of the carbon dioxide (CO2) gas from deep storage reservoirs. The main objectives of this work are as follows: • Develop a systematic understanding of how CO2 leakage is likely to influence pertinent geochemical processes (e.g., dissolution/precipitation, sorption/desorption and redox reactions) in the aquifer sediments. • Identify prevailing environmental conditions that would dictate one geochemical outcome over another. • Gather useful information to support site selection, risk assessment, policy-making, and public education efforts associated with geological carbon sequestration. In this report, we present results from experiments conducted at PNNL to address research issues related to the main objectives of this effort. A series of batch and column experiments and solid phase characterization studies (quantitative x-ray diffraction and wet chemical extractions with a concentrated acid) were conducted with representative rocks and sediments from an unconfined, oxidizing carbonate aquifer, i.e., Edwards aquifer in Texas, and a confined aquifer, i.e., the High Plains aquifer in Kansas. These materials were exposed to a CO2 gas stream simulating CO2 gas leaking scenarios, and changes in aqueous phase pH and chemical composition were measured in liquid and effluent samples collected at pre-determined experimental times. Additional research to be conducted during the current fiscal year will further validate these results and will address other important remaining issues. Results from these experimental efforts will provide valuable insights for the development of site-specific, generation III reduced order models. In addition, results will initially serve as input parameters during model calibration runs and, ultimately, will be used to test model predictive capability and

  9. IMPROVING CO2 EFFICIENCY FOR RECOVERING OIL IN HETEROGENEOUS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Reid B. Grigg; Robert K. Svec; Zhengwen Zeng; Baojun Bai; Yi Liu

    2004-09-27

    The third annual report of ''Improving CO{sub 2} Efficiency for Recovery Oil in Heterogeneous Reservoirs'' presents results of laboratory studies with related analytical models for improved oil recovery. All studies were designed to optimize utilization and extend the practice of CO{sub 2} flooding to a wider range of reservoirs. Chapter 1 describes the behavior at low concentrations of the surfactant Chaser International CD1045{trademark} (CD) versus different salinity, pressure and temperature. Results of studies on the effects of pH and polymer (hydrolyzed polyacrylamide?HPAM) and CO{sub 2} foam stability after adsorption in the core are also reported. Calcium lignosulfonate (CLS) transport mechanisms through sandstone, description of the adsorption of CD and CD/CLS onto three porous media (sandstone, limestone and dolomite) and five minerals, and the effect of adsorption on foam stability are also reported. In Chapter 2, the adsorption kinetics of CLS in porous Berea sandstone and non-porous minerals are compared by monitoring adsorption density change with time. Results show that adsorption requires a much longer time for the porous versus non-porous medium. CLS adsorption onto sandstone can be divided into three regions: adsorption controlled by dispersion, adsorption controlled by diffusion and adsorption equilibrium. NaI tracer used to characterize the sandstone had similar trends to earlier results for the CLS desorption process, suggesting a dual porosity model to simulate flow through Berea sandstone. The kinetics and equilibrium test for CD adsorption onto five non-porous minerals and three porous media are reported in Chapter 3. CD adsorption and desorption onto non-porous minerals can be established in less than one hour with adsorption densities ranging from 0.4 to 1.2 mg of CD per g of mineral in decreasing order of montmorillonite, dolomite, kaolinite, silica and calcite. The surfactant adsorption onto three porous media takes

  10. Three-dimensional imaging of aquifer and aquitard heterogeneity via transient hydraulic tomography at a highly heterogeneous field site

    Science.gov (United States)

    Zhao, Zhanfeng; Illman, Walter A.

    2018-04-01

    Previous studies have shown that geostatistics-based transient hydraulic tomography (THT) is robust for subsurface heterogeneity characterization through the joint inverse modeling of multiple pumping tests. However, the hydraulic conductivity (K) and specific storage (Ss) estimates can be smooth or even erroneous for areas where pumping/observation densities are low. This renders the imaging of interlayer and intralayer heterogeneity of highly contrasting materials including their unit boundaries difficult. In this study, we further test the performance of THT by utilizing existing and newly collected pumping test data of longer durations that showed drawdown responses in both aquifer and aquitard units at a field site underlain by a highly heterogeneous glaciofluvial deposit. The robust performance of the THT is highlighted through the comparison of different degrees of model parameterization including: (1) the effective parameter approach; (2) the geological zonation approach relying on borehole logs; and (3) the geostatistical inversion approach considering different prior information (with/without geological data). Results reveal that the simultaneous analysis of eight pumping tests with the geostatistical inverse model yields the best results in terms of model calibration and validation. We also find that the joint interpretation of long-term drawdown data from aquifer and aquitard units is necessary in mapping their full heterogeneous patterns including intralayer variabilities. Moreover, as geological data are included as prior information in the geostatistics-based THT analysis, the estimated K values increasingly reflect the vertical distribution patterns of permeameter-estimated K in both aquifer and aquitard units. Finally, the comparison of various THT approaches reveals that differences in the estimated K and Ss tomograms result in significantly different transient drawdown predictions at observation ports.

  11. On-farm irrigation reservoirs for surface water storage in eastern Arkansas: Trends in construction in response to aquifer depletion

    Science.gov (United States)

    Yaeger, M. A.; Reba, M. L.; Massey, J. H.; Adviento-Borbe, A.

    2017-12-01

    On-farm surface water storage reservoirs have been constructed to address declines in the Mississippi River Valley Alluvial aquifer, the primary source of irrigation for most of the row crops grown in eastern Arkansas. These reservoirs and their associated infrastructure represent significant investments in financial and natural resources, and may cause producers to incur costs associated with foregone crop production and long-term maintenance. Thus, an analysis of reservoir construction trends in the Grand Prairie Critical Groundwater Area (GPCGA) and Cache River Critical Groundwater Area (CRCGA) was conducted to assist future water management decisions. Between 1996 and 2015, on average, 16 and 4 reservoirs were constructed per year, corresponding to cumulative new reservoir surface areas of 161 and 60 ha yr-1, for the GPCGA and the CRCGA, respectively. In terms of reservoir locations relative to aquifer status, after 1996, 84.5% of 309 total reservoirs constructed in the GPCGA and 91.0% of 78 in the CRCGA were located in areas with remaining saturated aquifer thicknesses of 50% or less. The majority of new reservoirs (74% in the GPCGA and 63% in the CRCGA) were constructed on previously productive cropland. The next most common land use, representing 11% and 15% of new reservoirs constructed in the GPCGA and CRCGA, respectively, was the combination of a field edge and a ditch, stream, or other low-lying area. Less than 10% of post-1996 reservoirs were constructed on predominately low-lying land, and the use of such lands decreased in both critical groundwater areas during the past 20 years. These disparities in reservoir construction rates, locations, and prior land uses is likely due to groundwater declines being first observed in the GPCGA as well as the existence of two large-scale river diversion projects under construction in the GPCGA that feature on-farm storage as a means to offset groundwater use.

  12. Some new hydraulic and tracer measurement techniques for heterogeneous aquifer formations

    International Nuclear Information System (INIS)

    Ptak, T.; Teutsch, G.

    1990-01-01

    Groundwater contamination assessment and remediation activities demand reliable techniques for the determination of the governing aquifer parameters and their spatial distribution. In order to define guidelines and recommendations, some existing underground investigation techniques were tested and new methods have been developed as a part of the research program at the Horkheimer Insel experimental field site. In this paper, some new developed field and laboratory techniques are introduced and the results compared for two example monitoring wells located in the northern part of the field site. It is shown that highly conductive and highly heterogeneous aquifers demand high resolution investigation techniques. For transport predictions, new methods are needed that are able to detect preferential flow paths. Results from multilevel tracer tests show that simple analytical interpretations are not valid for this type of aquifer. (Author) (8 refs., 12 figs., tab.)

  13. IMPROVING CO2 EFFICIENCY FOR RECOVERING OIL IN HETEROGENEOUS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Reid B. Grigg; Robert K. Svec

    2002-12-20

    This document is the First Annual Report for the U.S. Department of Energy under contract No., a three-year contract entitled: ''Improving CO{sub 2} Efficiency for Recovering Oil in Heterogeneous Reservoirs.'' The research improved our knowledge and understanding of CO{sub 2} flooding and includes work in the areas of injectivity and mobility control. The bulk of this work has been performed by the New Mexico Petroleum Recovery Research Center, a research division of New Mexico Institute of Mining and Technology. This report covers the reporting period of September 28, 2001 and September 27, 2002. Injectivity continues to be a concern to the industry. During this period we have contacted most of the CO{sub 2} operators in the Permian Basin and talked again about their problems in this area. This report has a summary of what we found. It is a given that carbonate mineral dissolution and deposition occur in a formation in geologic time and are expected to some degree in carbon dioxide (CO{sub 2}) floods. Water-alternating-gas (WAG) core flood experiments conducted on limestone and dolomite core plugs confirm that these processes can occur over relatively short time periods (hours to days) and in close proximity to each other. Results from laboratory CO{sub 2}-brine flow experiments performed in rock core were used to calibrate a reactive transport simulator. The calibrated model is being used to estimate in situ effects of a range of possible sequestration options in depleted oil/gas reservoirs. The code applied in this study is a combination of the well known TOUGH2 simulator, for coupled groundwater/brine and heat flow, with the chemistry code TRANS for chemically reactive transport. Variability in response among rock types suggests that CO{sub 2} injection will induce ranges of transient and spatially dependent changes in intrinsic rock permeability and porosity. Determining the effect of matrix changes on CO{sub 2} mobility is crucial in

  14. Influence of confining layers' heterogeneity on the barometric response functions in semi-confined aquifers

    Science.gov (United States)

    Redaelli, Marco; Perulero Serrano, Raul

    2017-04-01

    It has been shown that Barometric Response Functions (BRFs) can provide a useful tool for detecting the occurrence of highly conducive bodies which span across aquifer confining layers and can potentially give rise to pathways for pollutant migration (Hussein et al 2013, Odling et al 2015). Analytical models employed to estimate BRFs from geological system properties assume homogeneity within the aquifer and its confining layer. These assumptions are rarely satisfied in practice. Our study focusses on the impact on predicted BRFs of heterogeneous distribution of high conductivity geomaterials within the confining layer. The work is grounded on a suite of three-dimensional, transient numerical computations of groundwater flow in a confining layer-aquifer system for i) a perfectly homogeneous two-layer setting where a single highly conducive block is fully penetrating the confining layer and ii) a heterogeneous two-layer system where hydraulic conductivity in the confining layer is modelled as a stochastic process. Our numerical results are interpreted through a comparison against those associated with an analytical model which assumes system homogeneity. Monitoring points located in the middle of the modelled aquifer domain, mimicking screened boreholes in field conditions, are used to extract water level records. The output is used to obtain the corresponding BRFs (in terms of gain and phase components) and compared vis-a-vis the selected analytical solution. The results show a wide variety of BRF responses, especially in the gain component, which vary from almost confined to unconfined scenarios. Our simulations show that the BRFs are a viable tool to improve understanding of the degree of spatial continuity within low permeability heterogeneous geological materials such as glacial till which is frequently found overlying water bearing units across the UK and other localities worldwide. As such, it has the potential to improve groundwater vulnerability assessment

  15. Numerical simulation of groundwater movement and managed aquifer recharge from Sand Hollow Reservoir, Hurricane Bench area, Washington County, Utah

    Science.gov (United States)

    Marston, Thomas M.; Heilweil, Victor M.

    2012-01-01

    The Hurricane Bench area of Washington County, Utah, is a 70 square-mile area extending south from the Virgin River and encompassing Sand Hollow basin. Sand Hollow Reservoir, located on Hurricane Bench, was completed in March 2002 and is operated primarily as a managed aquifer recharge project by the Washington County Water Conservancy District. The reservoir is situated on a thick sequence of the Navajo Sandstone and Kayenta Formation. Total recharge to the underlying Navajo aquifer from the reservoir was about 86,000 acre-feet from 2002 to 2009. Natural recharge as infiltration of precipitation was approximately 2,100 acre-feet per year for the same period. Discharge occurs as seepage to the Virgin River, municipal and irrigation well withdrawals, and seepage to drains at the base of reservoir dams. Within the Hurricane Bench area, unconfined groundwater-flow conditions generally exist throughout the Navajo Sandstone. Navajo Sandstone hydraulic-conductivity values from regional aquifer testing range from 0.8 to 32 feet per day. The large variability in hydraulic conductivity is attributed to bedrock fractures that trend north-northeast across the study area.A numerical groundwater-flow model was developed to simulate groundwater movement in the Hurricane Bench area and to simulate the movement of managed aquifer recharge from Sand Hollow Reservoir through the groundwater system. The model was calibrated to combined steady- and transient-state conditions. The steady-state portion of the simulation was developed and calibrated by using hydrologic data that represented average conditions for 1975. The transient-state portion of the simulation was developed and calibrated by using hydrologic data collected from 1976 to 2009. Areally, the model grid was 98 rows by 76 columns with a variable cell size ranging from about 1.5 to 25 acres. Smaller cells were used to represent the reservoir to accurately simulate the reservoir bathymetry and nearby monitoring wells; larger

  16. Impact of Temporally Variable and Uniform Pumping Regimes on Contaminant Transport in Heterogeneous Aquifers

    Science.gov (United States)

    Libera, A.; de Barros, F.; Guadagnini, A.

    2015-12-01

    We study and compare the effect of temporally variable and uniform pumping regimes on key features of contaminant transport in a randomly heterogeneous aquifer. Pumping wells are used for groundwater supply in the context of urban, agricultural, and industrial activities. Groundwater management agencies typically schedule groundwater extraction through a predefined sequence of pumping periods to balance benefits to anthropogenic activities and environmental needs. The impact of the spatial variability of aquifer hydraulic properties, such as hydraulic conductivity, on contaminant transport and associated solute residence times are widely studied. Only a limited number of studies address the way a given pumping schedule affects contaminant plume behavior in heterogeneous aquifers. In this context, the feedback between a transient pumping regime and contaminant breakthrough curves is largely unexplored. Our goal is to investigate the way diverse groundwater extraction strategies affect the history of solute concentration recovered at the well while accounting for the natural variability of the geological system, in the presence of incomplete information on hydraulic conductivity distribution. Considering the joint effects of spatially heterogeneous hydraulic conductivity and temporally varying well pumping rates, this work offers a realistic evaluation of groundwater contamination risk. The latter is here considered in the context of human health and is quantified in terms of the probability that harm will result from exposure to a contaminant found in groundwater. Two scenarios are considered: a pumping well that extracts a given amount of water operating (a) at a constant pumping rate and (b) under transient conditions. The analysis is performed within a numerical Monte Carlo framework. We probe the impact of diverse geostatistical structures to describe aquifer heterogeneity on solute breakthrough curves and the statistics of target environmental performance

  17. Heat and mass transport during a groundwater replenishment trial in a highly heterogeneous aquifer

    Science.gov (United States)

    Seibert, Simone; Prommer, Henning; Siade, Adam; Harris, Brett; Trefry, Mike; Martin, Michael

    2014-12-01

    Changes in subsurface temperature distribution resulting from the injection of fluids into aquifers may impact physiochemical and microbial processes as well as basin resource management strategies. We have completed a 2 year field trial in a hydrogeologically and geochemically heterogeneous aquifer below Perth, Western Australia in which highly treated wastewater was injected for large-scale groundwater replenishment. During the trial, chloride and temperature data were collected from conventional monitoring wells and by time-lapse temperature logging. We used a joint inversion of these solute tracer and temperature data to parameterize a numerical flow and multispecies transport model and to analyze the solute and heat propagation characteristics that prevailed during the trial. The simulation results illustrate that while solute transport is largely confined to the most permeable lithological units, heat transport was also affected by heat exchange with lithological units that have a much lower hydraulic conductivity. Heat transfer by heat conduction was found to significantly influence the complex temporal and spatial temperature distribution, especially with growing radial distance and in aquifer sequences with a heterogeneous hydraulic conductivity distribution. We attempted to estimate spatially varying thermal transport parameters during the data inversion to illustrate the anticipated correlations of these parameters with lithological heterogeneities, but estimates could not be uniquely determined on the basis of the collected data.

  18. A Review of the Multilevel Slug Test for Characterizing Aquifer Heterogeneity

    Directory of Open Access Journals (Sweden)

    Chia-Shyun Chen

    2012-01-01

    Full Text Available All aquifers are heterogeneous to a certain degree. The spatial distribution of hydraulic conductivity K(x, y, z, or aquifer heterogeneity, significantly influences the groundwater flow movement and associated solute transport. Of particular importance in designing an in-situ remediation plan is a knowledge of low-K layers because they are less accessible to remedial agents and form a bottleneck in remediation. The characterization of aquifer heterogeneity is essential to the solution of many practical and scientific groundwater problems. This article reviews the field technique using the multilevel slug test (MLST, which determines a series of K estimates at depths of interest in a well by making use of a double-packer system. The K(z obtained manifests the vertical variation of hydraulic conductivity in the vicinity of the test well, and the combination of K(z from different wells gives rise to a three-dimensional description of K(x, y, z. The MLST response is rather sensitive to hydraulic conductivity variation; e.g., it is oscillatory for highly permeable conditions (K > 5 × 10-4 m s-1 and a nonoscillatory for K < 5 × 10-4 m s-1. In this article we discuss the instrumentation of the double-packer system, the implementation of the depth-specific slug test, the data analysis methods for a spectrum of response characteristics usually observed in the field, and field applications of the MLST.

  19. Characterizing flow pathways in a sandstone aquifer: Tectonic vs sedimentary heterogeneities

    Science.gov (United States)

    Medici, G.; West, L. J.; Mountney, N. P.

    2016-11-01

    Sandstone aquifers are commonly assumed to represent porous media characterized by a permeable matrix. However, such aquifers may be heavy fractured when rock properties and timing of deformation favour brittle failure and crack opening. In many aquifer types, fractures associated with faults, bedding planes and stratabound joints represent preferential pathways for fluids and contaminants. In this paper, well test and outcrop-scale studies reveal how strongly lithified siliciclastic rocks may be entirely dominated by fracture flow at shallow depths (≤ 180 m), similar to limestone and crystalline aquifers. However, sedimentary heterogeneities can primarily control fluid flow where fracture apertures are reduced by overburden pressures or mineral infills at greater depths. The Triassic St Bees Sandstone Formation (UK) of the East Irish Sea Basin represents an optimum example for study of the influence of both sedimentary and tectonic aquifer heterogeneities in a strongly lithified sandstone aquifer-type. This fluvial sedimentary succession accumulated in rapidly subsiding basins, which typically favours preservation of complete depositional cycles including fine grained layers (mudstone and silty sandstone) interbedded in sandstone fluvial channels. Additionally, vertical joints in the St Bees Sandstone Formation form a pervasive stratabound system whereby joints terminate at bedding discontinuities. Additionally, normal faults are present through the succession showing particular development of open-fractures. Here, the shallow aquifer (depth ≤ 180 m) was characterized using hydro-geophysics. Fluid temperature, conductivity and flow-velocity logs record inflows and outflows from normal faults, as well as from pervasive bed-parallel fractures. Quantitative flow logging analyses in boreholes that cut fault planes indicate that zones of fault-related open fractures characterize 50% of water flow. The remaining flow component is dominated by bed-parallel fractures

  20. Mixing effects on apparent reaction rates and isotope fractionation during denitrification in a heterogeneous aquifer

    Science.gov (United States)

    Green, C.T.; Böhlke, J.K.; Bekins, B.A.; Phillips, S.P.

    2010-01-01

    Gradients in contaminant concentrations and isotopic compositions commonly are used to derive reaction parameters for natural attenuation in aquifers. Differences between field-scale (apparent) estimated reaction rates and isotopic fractionations and local-scale (intrinsic) effects are poorly understood for complex natural systems. For a heterogeneous alluvial fan aquifer, numerical models and field observations were used to study the effects of physical heterogeneity on reaction parameter estimates. Field measurements included major ions, age tracers, stable isotopes, and dissolved gases. Parameters were estimated for the O2 reduction rate, denitrification rate, O 2 threshold for denitrification, and stable N isotope fractionation during denitrification. For multiple geostatistical realizations of the aquifer, inverse modeling was used to establish reactive transport simulations that were consistent with field observations and served as a basis for numerical experiments to compare sample-based estimates of "apparent" parameters with "true" (intrinsic) values. For this aquifer, non-Gaussian dispersion reduced the magnitudes of apparent reaction rates and isotope fractionations to a greater extent than Gaussian mixing alone. Apparent and true rate constants and fractionation parameters can differ by an order of magnitude or more, especially for samples subject to slow transport, long travel times, or rapid reactions. The effect of mixing on apparent N isotope fractionation potentially explains differences between previous laboratory and field estimates. Similarly, predicted effects on apparent O2 threshold values for denitrification are consistent with previous reports of higher values in aquifers than in the laboratory. These results show that hydrogeological complexity substantially influences the interpretation and prediction of reactive transport. ?? 2010 by the American Geophysical Union.

  1. Mixing effects on apparent reaction rates and isotope fractionation during denitrification in a heterogeneous aquifer

    Science.gov (United States)

    Green, Christopher T.; Böhlke, John Karl; Bekins, Barbara A.; Phillips, Steven P.

    2010-01-01

    Gradients in contaminant concentrations and isotopic compositions commonly are used to derive reaction parameters for natural attenuation in aquifers. Differences between field‐scale (apparent) estimated reaction rates and isotopic fractionations and local‐scale (intrinsic) effects are poorly understood for complex natural systems. For a heterogeneous alluvial fan aquifer, numerical models and field observations were used to study the effects of physical heterogeneity on reaction parameter estimates. Field measurements included major ions, age tracers, stable isotopes, and dissolved gases. Parameters were estimated for the O2 reduction rate, denitrification rate, O2 threshold for denitrification, and stable N isotope fractionation during denitrification. For multiple geostatistical realizations of the aquifer, inverse modeling was used to establish reactive transport simulations that were consistent with field observations and served as a basis for numerical experiments to compare sample‐based estimates of “apparent” parameters with “true“ (intrinsic) values. For this aquifer, non‐Gaussian dispersion reduced the magnitudes of apparent reaction rates and isotope fractionations to a greater extent than Gaussian mixing alone. Apparent and true rate constants and fractionation parameters can differ by an order of magnitude or more, especially for samples subject to slow transport, long travel times, or rapid reactions. The effect of mixing on apparent N isotope fractionation potentially explains differences between previous laboratory and field estimates. Similarly, predicted effects on apparent O2threshold values for denitrification are consistent with previous reports of higher values in aquifers than in the laboratory. These results show that hydrogeological complexity substantially influences the interpretation and prediction of reactive transport.

  2. Geologic CO2 Sequestration: Predicting and Confirming Performance in Oil Reservoirs and Saline Aquifers

    Science.gov (United States)

    Johnson, J. W.; Nitao, J. J.; Newmark, R. L.; Kirkendall, B. A.; Nimz, G. J.; Knauss, K. G.; Ziagos, J. P.

    2002-05-01

    Reducing anthropogenic CO2 emissions ranks high among the grand scientific challenges of this century. In the near-term, significant reductions can only be achieved through innovative sequestration strategies that prevent atmospheric release of large-scale CO2 waste streams. Among such strategies, injection into confined geologic formations represents arguably the most promising alternative; and among potential geologic storage sites, oil reservoirs and saline aquifers represent the most attractive targets. Oil reservoirs offer a unique "win-win" approach because CO2 flooding is an effective technique of enhanced oil recovery (EOR), while saline aquifers offer immense storage capacity and widespread distribution. Although CO2-flood EOR has been widely used in the Permian Basin and elsewhere since the 1980s, the oil industry has just recently become concerned with the significant fraction of injected CO2 that eludes recycling and is therefore sequestered. This "lost" CO2 now has potential economic value in the growing emissions credit market; hence, the industry's emerging interest in recasting CO2 floods as co-optimized EOR/sequestration projects. The world's first saline aquifer storage project was also catalyzed in part by economics: Norway's newly imposed atmospheric emissions tax, which spurred development of Statoil's unique North Sea Sleipner facility in 1996. Successful implementation of geologic sequestration projects hinges on development of advanced predictive models and a diverse set of remote sensing, in situ sampling, and experimental techniques. The models are needed to design and forecast long-term sequestration performance; the monitoring techniques are required to confirm and refine model predictions and to ensure compliance with environmental regulations. We have developed a unique reactive transport modeling capability for predicting sequestration performance in saline aquifers, and used it to simulate CO2 injection at Sleipner; we are now

  3. Nominal Range Sensitivity Analysis of peak radionuclide concentrations in randomly heterogeneous aquifers

    International Nuclear Information System (INIS)

    Cadini, F.; De Sanctis, J.; Cherubini, A.; Zio, E.; Riva, M.; Guadagnini, A.

    2012-01-01

    Highlights: ► Uncertainty quantification problem associated with the radionuclide migration. ► Groundwater transport processes simulated within a randomly heterogeneous aquifer. ► Development of an automatic sensitivity analysis for flow and transport parameters. ► Proposal of a Nominal Range Sensitivity Analysis approach. ► Analysis applied to the performance assessment of a nuclear waste repository. - Abstract: We consider the problem of quantification of uncertainty associated with radionuclide transport processes within a randomly heterogeneous aquifer system in the context of performance assessment of a near-surface radioactive waste repository. Radionuclide migration is simulated at the repository scale through a Monte Carlo scheme. The saturated groundwater flow and transport equations are then solved at the aquifer scale for the assessment of the expected radionuclide peak concentration at a location of interest. A procedure is presented to perform the sensitivity analysis of this target environmental variable to key parameters that characterize flow and transport processes in the subsurface. The proposed procedure is exemplified through an application to a realistic case study.

  4. A stochastic model of reactive solute transport with time-varying velocity in a heterogeneous aquifer

    Science.gov (United States)

    Kabala, Z. J.; Sposito, Garrison

    1991-03-01

    The cumulant expansion method, used previously by Sposito and Barry (1987) to derive an ensemble average transport equation for a tracer moving in a heterogeneous aquifer, is generalized to the case of a reactive solute that can adsorb linearly and undergo first-order decay. In the process we also generalize the Van Kampen (1987) result for the cumulant expansion of a multiplicative stochastic differential equation containing a time-dependent sure matrix. The resulting partial differential equation exhibits terms with field-scale coefficients that are analogous to those in the corresponding nonstochastic local-scale transport equation. There are also new terms in the third- and fourth-order spatial derivatives of the ensemble average concentration. It is demonstrated that the effective solute velocity for the aqueous concentration, not that for the total concentration (aqueous plus sorbed), is relevant for a field-scale description of solute transport. The field-scale effective solute velocity, dispersion coefficient, retardation factor, and first-order decay parameters, unlike their local-scale counterparts, are time-dependent because of autocorrelations and cross correlations among the random local solute velocity, retardation factor, and first-order decay constant. It is shown also that negative cross correlations between the random tracer solute velocity and the inverse of the local retardation factor may produce both enhanced dispersion and a temporal growth in the field-scale retardation factor. These effects are possible in any heterogeneous aquifer for which a stochastic description of aquifer spatial variability is appropriate.

  5. Analysis of structural heterogeneities on drilled cores: a reservoir modeling oriented methodology; Analyse des heterogeneites structurales sur carottes: une methodologie axee vers la modelisation des reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Cortes, P.; Petit, J.P. [Montpellier-2 Univ., Lab. de Geophysique, Tectonique et Sedimentologie, UMR CNRS 5573, 34 (France); Guy, L. [ELF Aquitaine Production, 64 - Pau (France); Thiry-Bastien, Ph. [Lyon-1 Univ., 69 (France)

    1999-07-01

    The characterization of structural heterogeneities of reservoirs is of prime importance for hydrocarbons recovery. A methodology is presented which allows to compare the dynamic behaviour of fractured reservoirs and the observation of microstructures on drilled cores or surface reservoir analogues. (J.S.)

  6. The influence of riverbed heterogeneity patterns on river-aquifer exchange fluxes under different connection regimes

    Science.gov (United States)

    Tang, Q.; Kurtz, W.; Schilling, O. S.; Brunner, P.; Vereecken, H.; Hendricks Franssen, H.-J.

    2017-11-01

    Riverbed hydraulic conductivity (K) is a critical parameter for the prediction of exchange fluxes between a river and an aquifer. In this study, the role of heterogeneity patterns was explored using the fully integrated hydrological model HydroGeoSphere simulating complex, variably saturated subsurface flow. A synthetic 3-D river-aquifer reference model was constructed with a heterogeneous riverbed using non-multi-Gaussian patterns in the form of meandering channels. Data assimilation was used to test the ability of different riverbed K patterns to reproduce hydraulic heads, riverbed K and river-aquifer exchange fluxes. Both fully saturated as well as variably saturated conditions underneath the riverbed were tested. The data assimilation experiments with the ensemble Kalman filter (EnKF) were carried out for four types of geostatistical models of riverbed K fields: (i) spatially homogeneous, (ii) heterogeneous with multi-Gaussian distribution, (iii) heterogeneous with non-multi-Gaussian distribution (channelized structures) and (iv) heterogeneous with non-multi-Gaussian distribution (elliptic structures). For all data assimilation experiments, state variables and riverbed K were updated by assimilating hydraulic heads. For saturated conditions, heterogeneous geostatistical models allowed a better characterization of net exchange fluxes than a homogeneous approximation. Among the three heterogeneous models, the performance of non-multi-Gaussian models was superior to the performance of the multi-Gaussian model, but the two tested non-multi-Gaussian models showed only small differences in performance from one another. For the variably saturated conditions both the multi-Gaussian model and the homogeneous model performed clearly worse than the two non-multi-Gaussian models. The two non-multi-Gaussian models did not show much difference in performance. This clearly shows that characterizing heterogeneity of riverbed K is important. Moreover, particularly under

  7. Using borehole flow logging to optimize hydraulic-test procedures in heterogeneous fractured aquifers

    Science.gov (United States)

    Paillet, F.L.

    1995-01-01

    Hydraulic properties of heterogeneous fractured aquifers are difficult to characterize, and such characterization usually requires equipment-intensive and time-consuming applications of hydraulic testing in situ. Conventional coring and geophysical logging techniques provide useful and reliable information on the distribution of bedding planes, fractures and solution openings along boreholes, but it is often unclear how these locally permeable features are organized into larger-scale zones of hydraulic conductivity. New boreholes flow-logging equipment provides techniques designed to identify hydraulically active fractures intersecting boreholes, and to indicate how these fractures might be connected to larger-scale flow paths in the surrounding aquifer. Potential complications in interpreting flowmeter logs include: 1) Ambient hydraulic conditions that mask the detection of hydraulically active fractures; 2) Inability to maintain quasi-steady drawdowns during aquifer tests, which causes temporal variations in flow intensity to be confused with inflows during pumping; and 3) Effects of uncontrolled background variations in hydraulic head, which also complicate the interpretation of inflows during aquifer tests. Application of these techniques is illustrated by the analysis of cross-borehole flowmeter data from an array of four bedrock boreholes in granitic schist at the Mirror Lake, New Hampshire, research site. Only two days of field operations were required to unambiguously identify the few fractures or fracture zones that contribute most inflow to boreholes in the CO borehole array during pumping. Such information was critical in the interpretation of water-quality data. This information also permitted the setting of the available string of two packers in each borehole so as to return the aquifer as close to pre-drilling conditions as possible with the available equipment.

  8. Improved Efficiency of Miscible CO2 Floods and Enhanced Prospects for CO2 Flooding Heterogeneous Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Grigg, Reid B.; Schechter, David S.

    1999-10-15

    The goal of this project is to improve the efficiency of miscible CO2 floods and enhance the prospects for flooding heterogeneous reservoirs. This report provides results of the second year of the three-year project that will be exploring three principles: (1) Fluid and matrix interactions (understanding the problems). (2) Conformance control/sweep efficiency (solving the problems. 3) Reservoir simulation for improved oil recovery (predicting results).

  9. Variations in hydraulic conductivity with scale of measurement during aquifer tests in heterogeneous, porous carbonate rocks

    Science.gov (United States)

    Schulze-Makuch, Dirk; Cherkauer, Douglas S.

    Previous studies have shown that hydraulic conductivity of an aquifer seems to increase as the portion of the aquifer tested increases. To date, such studies have all relied on different methods to determine hydraulic conductivity at each scale of interest, which raises the possibility that the observed increase in hydraulic conductivity is due to the measurement method, not to the scale. This study analyzes hydraulic conductivity with respect to scale during individual aquifer tests in porous, heterogeneous carbonate rocks in southeastern Wisconsin, USA. Results from this study indicate that hydraulic conductivity generally increases during an individual test as the volume of aquifer impacted increases, and the rate of this increase is the same as the rate of increase determined by using different measurement methods. Thus, scale dependence of hydraulic conductivity during single tests does not depend on the method of measurement. This conclusion is supported by 22 of 26 aquifer tests conducted in porous-flow-dominated carbonate units within the aquifer. Instead, scale dependency is probably caused by heterogeneities within the aquifer, a conclusion supported by digital simulation. All of the observed types of hydraulic-conductivity variations with scale during individual aquifer tests can be explained by a conceptual model of a simple heterogeneous aquifer composed of high-conductivity zones within a low-conductivity matrix. Résumé Certaines études ont montré que la conductivité hydraulique d'un aquifère semble augmenter en même temps que la partie testée de l'aquifère s'étend. Jusqu'à présent, ces études ont toutes reposé sur des méthodes de détermination de la conductivité hydraulique différentes pour chaque niveau d'échelle, ce qui a conduit à penser que l'augmentation observée de la conductivité hydraulique pouvait être due aux méthodes de mesure et non à l'effet d'échelle. Cette étude analyse la conductivité hydraulique par

  10. Prediction of Gas Injection Performance for Heterogeneous Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Franklin M. Orr, Jr; Martin J. Blunt

    1998-03-31

    This project performs research in four main areas: laboratory experiments to measure three-phase relative permeability; network modeling to predict three-phase relative perme- ability; benchmark simulations of gas injection and waterfl ooding at the field scale; and the development of fast streamline techniques to study field-scale oil. The aim of the work is to achieve a comprehensive description of gas injection processes from the pore to the core to the reservoir scale. In this report we provide a detailed description of our measurements of three-phase relative permeability.

  11. Assessment of managed aquifer recharge at Sand Hollow Reservoir, Washington County, Utah, updated to conditions through 2007

    Science.gov (United States)

    Heilweil, Victor M.; Ortiz, Gema; Susong, David D.

    2009-01-01

    Sand Hollow Reservoir in Washington County, Utah, was completed in March 2002 and is operated primarily as an aquifer storage and recovery project by the Washington County Water Conservancy District (WCWCD). Since its inception in 2002 through 2007, surface-water diversions of about 126,000 acre-feet to Sand Hollow Reservoir have resulted in a generally rising reservoir stage and surface area. Large volumes of runoff during spring 2005-06 allowed the WCWCD to fill the reservoir to a total storage capacity of more than 50,000 acre-feet, with a corresponding surface area of about 1,300 acres and reservoir stage of about 3,060 feet during 2006. During 2007, reservoir stage generally decreased to about 3,040 feet with a surface-water storage volume of about 30,000 acre-feet. Water temperature in the reservoir shows large seasonal variation and has ranged from about 3 to 30 deg C from 2003 through 2007. Except for anomalously high recharge rates during the first year when the vadose zone beneath the reservoir was becoming saturated, estimated ground-water recharge rates have ranged from 0.01 to 0.09 feet per day. Estimated recharge volumes have ranged from about 200 to 3,500 acre-feet per month from March 2002 through December 2007. Total ground-water recharge during the same period is estimated to have been about 69,000 acre-feet. Estimated evaporation rates have varied from 0.04 to 0.97 feet per month, resulting in evaporation losses of 20 to 1,200 acre-feet per month. Total evaporation from March 2002 through December 2007 is estimated to have been about 25,000 acre-feet. Results of water-quality sampling at monitoring wells indicate that by 2007, managed aquifer recharge had arrived at sites 37 and 36, located 60 and 160 feet from the reservoir, respectively. However, different peak arrival dates for specific conductance, chloride, chloride/bromide ratios, dissolved oxygen, and total dissolved-gas pressures at each monitoring well indicate the complicated nature of

  12. Reservoir characterisation of aquifers for direct heat production: Methodology and screening of the potental reservoirs for the Netherlands

    NARCIS (Netherlands)

    Pluymaekers, M.P.D.; Kramers, L.; Wees, J.-D., van; Kronimus, A.; Nelskamp, S.; Boxem, T.; Bonté, D.

    2012-01-01

    Geothermal low enthalpy heat in non-magmatic areas can be produced by pumping hot water from aquifers at large depth (>1 km). Key parameters for aquifer performance are temperature, depth, thickness and permeability. Geothermal exploration in the Netherlands can benefit considerably from the

  13. Identifying functional zones of denitrification in heterogeneous aquifer systems by numerical simulations - a case study

    Science.gov (United States)

    Jang, E.; Kalbacher, T.; He, W.; Shao, H.; Schueth, C.; Kolditz, O.

    2014-12-01

    Nitrate contamination in shallow groundwater is still one of the common problems in many countries. Because of its high solubility and anionic nature, nitrate can easily leach through soil and persist in groundwater for decades. High nitrate concentration has been suggested as a major cause of accelerated eutrophication, methemoglobinemia and gastric cancer. There are several factors influencing the fate of nitrate in groundwater system, which is e.g. distribution of N- sources to soil and groundwater, distribution and amount of reactive substances maintaining denitrification, rate of nitrate degradation and its kinetics, and geological characteristics of the aquifer. Nitrate transport and redox transformation processes are closely linked to complex and spatially distributed physical and chemical interaction, therefore it is difficult to predict and quantify in the field and laboratory experiment. Models can play a key role in elucidation of nitrate reduction pathway in groundwater system and in the design and evaluation of field tests to investigate in situ remediation technologies as well. The goal of the current study is to predict groundwater vulnerability to nitrate, to identify functional zones of denitrification in heterogeneous aquifer systems and to describe the uncertainty of the predictions due to scale effects. For this aim, we developed a kinetic model using multi-component mass transport code OpenGeoSys coupling with IPhreeqc module of the geochemical solver PHREEQC. The developed model included sequential aerobic and nitrate-based respiration, multi-Monod kinetics, multi-species biogeochemical reactions, and geological characteristics of the groundwater aquifer. Moreover water-rock interaction such as secondary mineral precipitation was also included in this model. In this presentation, we focused on the general modelling approach and present the simulation results of nitrate transport simulation in a hypothetical aquifer systems based on data from

  14. Coupling ground and airborne geophysical data with upscaling techniques for regional groundwater modeling of heterogeneous aquifers: Case study of a sedimentary aquifer intruded by volcanic dykes in Northern Ireland

    OpenAIRE

    Dickson, Neil Edwin Matthew; Comte, Jean-Christophe; McKinley, Jennifer; Ofterdinger, Ulrich

    2014-01-01

    In highly heterogeneous aquifer systems, conceptualization of regional groundwater flow models frequently results in the generalization or negligence of aquifer heterogeneities, both of which may result in erroneous model outputs. The calculation of equivalence related to hydrogeological parameters and applied to upscaling provides a means of accounting for measurement scale information but at regional scale. In this study, the Permo-Triassic Lagan Valley strategic aquifer in Northern Ireland...

  15. Aquifers

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This map layer contains the shallowest principal aquifers of the conterminous United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands, portrayed as polygons....

  16. Evaluating Traditional Hydrogeologic Characterization Approaches in a Highly Heterogeneous Glaciofluvial Aquifer

    Science.gov (United States)

    Alexander, M.; Berg, S. J.; Illman, W.

    2009-05-01

    Hydraulic conductivity (K) and specific storage (Ss) estimates are two of the most essential parameters when designing transient groundwater flow models which are commonly used in contaminant transport and water resource investigations. The purpose of this study was to evaluate the effectiveness of traditional hydrogeologic characterization approaches in a highly heterogeneous glaciofluvial aquifer at the North Campus Research Site (NCRS) situated on the University of Waterloo campus. The site is instrumented with four Continuous Multichannel Tubing (CMT) wells containing a total of 28 monitoring points and a multi-screen well used for pumping at different elevations. Continuous soil cores to a depth of approximately 18 m were collected during the installation of the CMTs and the multi-screen well. The cores were subsequently characterized using the Unified Soil Classification System and grain size analysis. Samples were obtained from the core at approximately 10 cm increments and a falling head permeameter was used to make 471 K estimates. The estimates from the falling head permeameter showed K to vary from 10-4 - 10-10 m/s illustrating the highly heterogeneous nature of the aquifer at the NCRS. A geostatistical analysis performed on the core K dataset yielded a strongly heterogeneous K field for the site. K and Ss estimates were also obtained via slug tests in the CMT ports through type curve analysis. Cross-hole pumping tests were conducted using the center multi-screened well and the 4 CMTs installed in a 5-spot pattern. Pumping was conducted in 7 zones using a straddle packer system and the corresponding drawdown responses were recorded in 28 zones in the CMTs and 3 zones in the center well using pressure transducers. The various K and Ss estimates were then evaluated by simulating the transient drawdown data using a 3D forward numerical model constructed using Hydrogeosphere (Therrien et al., 2005). Simulation was conducted using 3 separate K and Ss fields

  17. LNAPL source zone delineation using soil gases in a heterogeneous silty-sand aquifer

    Science.gov (United States)

    Cohen, Grégory J. V.; Jousse, Florie; Luze, Nicolas; Höhener, Patrick; Atteia, Olivier

    2016-09-01

    Source delineation of hydrocarbon contaminated sites is of high importance for remediation work. However, traditional methods like soil core extraction and analysis or recent Membrane Interface Probe methods are time consuming and costly. Therefore, the development of an in situ method based on soil gas analysis can be interesting. This includes the direct measurement of volatile organic compounds (VOCs) in soil gas taken from gas probes using a PID (Photo Ionization Detector) and the analysis of other soil gases related to VOC degradation distribution (CH4, O2, CO2) or related to presence of Light Non-Aqueous Phase Liquid (LNAPL) as 222Rn. However, in widespread heterogeneous formations, delineation by gas measurements becomes more challenging. The objective of this study is twofold: (i) to analyse the potential of several in situ gas measurement techniques in comparison to soil coring for LNAPL source delineation at a heterogeneous contaminated site where the techniques might be limited by a low diffusion potential linked to the presence of fine sands and silts, and (ii) to analyse the effect of vertical sediment heterogeneities on the performance of these gas measurement methods. Thus, five types of gases were analysed: VOCs, their three related degradation products O2, CO2 and CH4 and 222Rn. Gas measurements were compared to independent LNAPL analysis by coring. This work was conducted at an old industrial site frequently contaminated by a Diesel-Fuel mixture located in a heterogeneous fine-grained aquifer. Results show that in such heterogeneous media migration of reactive gases like VOCs occurs only across small distances and the VOC concentrations sampled with gas probes are mainly related to local conditions rather than the presence of LNAPL below the gas probe. 222Rn is not well correlated with LNAPL because of sediment heterogeneity. Oxygen, CO2, and especially CH4, have larger lengths of diffusion and give the clearest picture for LNAPL presence at this

  18. Dispersion measurement as a method of quantifying geologic characterization and defining reservoir heterogeneity. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Menzie, D.E.

    1995-05-01

    The main objective of this research project is to investigate dispersion as a method of quantifying geological characterization and defining reservoir heterogeneity in order to enhance crude oil recovery. The dispersion of flow of a reservoir rock (dispersion coefficient and dispersivity) was identified as one of the physical properties of a reservoir rock by measuring the mixing of two miscible fluids, one displacing the other in a porous medium. A rock was 100% saturated with a resident fluid and displaced by a miscible fluid of equal viscosity and equal density. Some specific experiments were performed with unequal densities. Produced fluid was analyzed by refractometer, nuclear reaction, electrical conductivity and X-ray scan. Several physical and flow characteristics were measured on the sand rock sample in order to establish correlations with the measured dispersion property. Absolute permeability, effective porosity, relative permeability, capillary pressure, the heterogeneity factor and electrical conductivity were used to better understand the flow system. Linear, transverse, 2-D and 3-D dispersions were measured and used to characterize the rock heterogeneity of the flow system. A new system of measuring dispersion was developed using a gas displacing gas system in a porous medium. An attempt was also made to determine the dispersion property of an actual reservoir from present day well log data on a producing well. 275 refs., 102 figs., 17 tabs.

  19. Reservoir heterogeneity in Carboniferous sandstone of the Black Warrior basin. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kugler, R.L.; Pashin, J.C.; Carroll, R.E.; Irvin, G.D.; Moore, H.E.

    1994-04-01

    Although oil production in the Black Warrior basin of Alabama is declining, additional oil may be produced through improved recovery strategies, such as waterflooding, chemical injection, strategic well placement, and infill drilling. High-quality characterization of reservoirs in the Black Warrior basin is necessary to utilize advanced technology to recover additional oil and to avoid premature abandonment of fields. This report documents controls on the distribution and producibility of oil from heterogeneous Carboniferous reservoirs in the Black Warrior basin of Alabama. The first part of the report summarizes the structural and depositional evolution of the Black Warrior basin and establishes the geochemical characteristics of hydrocarbon source rocks and oil in the basin. This second part characterizes facies heterogeneity and petrologic and petrophysical properties of Carter and Millerella sandstone reservoirs. This is followed by a summary of oil production in the Black Warrior basin and an evaluation of seven improved-recovery projects in Alabama. In the final part, controls on the producibility of oil from sandstone reservoirs are discussed in terms of a scale-dependent heterogeneity classification.

  20. Reservoir heterogeneity in carboniferous sandstone of the Black Warrior basin. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kugler, R.L.; Pashin, J.C.; Carroll, R.E.; Irvin, G.D.; Moore, H.E.

    1994-06-01

    Although oil production in the Black Warrior basin of Alabama is declining, additional oil may be produced through improved recovery strategies, such as waterflooding, chemical injection, strategic well placement, and infill drilling. High-quality characterization of reservoirs in the Black Warrior basin is necessary to utilize advanced technology to recover additional oil and to avoid premature abandonment of fields. This report documents controls on the distribution and producibility of oil from heterogeneous Carboniferous reservoirs in the Black Warrior basin of Alabama. The first part of the report summarizes the structural and depositional evolution of the Black Warrior basin and establishes the geochemical characteristics of hydrocarbon source rocks and oil in the basin. This second part characterizes facies heterogeneity and petrologic and petrophysical properties of Carter and Millerella sandstone reservoirs. This is followed by a summary of oil production in the Black Warrior basin and an evaluation of seven improved-recovery projects in Alabama. In the final part, controls on the producibility of oil from sandstone reservoirs are discussed in terms of a scale-dependent heterogeneity classification.

  1. Effects of reservoir heterogeneity on scaling of effective mass transfer coefficient for solute transport

    Science.gov (United States)

    Leung, Juliana Y.; Srinivasan, Sanjay

    2016-09-01

    Modeling transport process at large scale requires proper scale-up of subsurface heterogeneity and an understanding of its interaction with the underlying transport mechanisms. A technique based on volume averaging is applied to quantitatively assess the scaling characteristics of effective mass transfer coefficient in heterogeneous reservoir models. The effective mass transfer coefficient represents the combined contribution from diffusion and dispersion to the transport of non-reactive solute particles within a fluid phase. Although treatment of transport problems with the volume averaging technique has been published in the past, application to geological systems exhibiting realistic spatial variability remains a challenge. Previously, the authors developed a new procedure where results from a fine-scale numerical flow simulation reflecting the full physics of the transport process albeit over a sub-volume of the reservoir are integrated with the volume averaging technique to provide effective description of transport properties. The procedure is extended such that spatial averaging is performed at the local-heterogeneity scale. In this paper, the transport of a passive (non-reactive) solute is simulated on multiple reservoir models exhibiting different patterns of heterogeneities, and the scaling behavior of effective mass transfer coefficient (Keff) is examined and compared. One such set of models exhibit power-law (fractal) characteristics, and the variability of dispersion and Keff with scale is in good agreement with analytical expressions described in the literature. This work offers an insight into the impacts of heterogeneity on the scaling of effective transport parameters. A key finding is that spatial heterogeneity models with similar univariate and bivariate statistics may exhibit different scaling characteristics because of the influence of higher order statistics. More mixing is observed in the channelized models with higher-order continuity. It

  2. Scale-up of miscible flood processes for heterogeneous reservoirs. Second annual report

    Energy Technology Data Exchange (ETDEWEB)

    Orr, F.M. Jr.

    1995-03-01

    Progress is reported for a comprehensive investigation of the scaling behavior of gas injection processes in heterogeneous reservoirs. The interplay of phase behavior, viscous fingering, gravity segregation, capillary imbibition and drainage, and reservoir heterogeneity is examined in a series of simulations and experiments. Use of streamtube to model multiphase flow is demonstrated to be a fast and accurate approach for displacements that are dominated by reservoir heterogeneity. The streamtube technique is particularly powerful for multiphase compositional displacements because it represents the effects of phase behavior with a one-dimensional flow and represents the effects of heterogeneity through the locations of streamtubes. A new approach for fast calculations of critical tie-lines directly from criticality conditions is reported. A global triangular structure solution for four-component flow systems, whose tie-lies meet at the edge of a quaternary phase diagram or lie in planes is presented. Also demonstrated is the extension of this solution to multicomponent systems under the same assumptions. The interplay of gravity, capillary and viscous forces on final residual oil saturation is examined experimentally and theoretically. The analysis of vertical equilibrium conditions for three-phase gravity drainage shows that almost all oil can be recovered from the top part of a reservoir. The prediction of spreading and stability of thin film is performed to investigate three-phase gravity drainage mechanisms. Finally, experimental results from gravity drainage of crude oil in the presence of CO{sub 2} suggest that gravity drainage could be an efficient oil recovery process for vertically fractured reservoirs.

  3. Modeling the Risk of Commercial Failure for Hydraulic Fracturing Projects Due to Reservoir Heterogeneity

    Directory of Open Access Journals (Sweden)

    Hadi Parvizi

    2018-01-01

    Full Text Available Hydraulic fracturing technologies play a major role in the global energy supply and affect oil pricing. The current oil price fluctuations within 40 to 55 USD per barrel have caused diminished economical margins for hydraulic fracturing projects. Hence, successful decision making the for execution of hydraulic fracturing projects requires a higher level of integration of technical, commercial, and uncertainty analyses. However, the complexity of hydraulic fracturing modeling, and the sensitivity and the effects of uncertainty of reservoir heterogeneity on well performance renders the integration of such studies rather impractical. The impact of reservoir heterogeneity on hydraulic fracturing performance has been quantified by the introduction of Heterogeneity Impact Factor (HIF and formulas have been developed to forecast well performance using HIF. These advances provide a platform for introducing a practical approach for introducing the Risk of Commercial Failure (RCF due to reservoir heterogeneity in hydraulic fracturing projects. This paper defines such a parameter and the methodology to calculate it in a time-efficient manner. The proposed approach has been exercised on a real project in which a RCF of 20% is computed. The analysis also covers the sensitivity on Capital Expenditure (CAPEX, Operational Expenditure (OPEX, gas price, HIF and discount rate.

  4. Determination of heterogeneity by high-resolution seismic reservoir characterization in the heavy oil Temblor reservoir of Coalinga Field, California

    Science.gov (United States)

    Mahapatra, Sailendra Nath

    The research focuses on analysis and subsurface imaging of siliciclastics rocks on steam-affected 3D poststack seismic data, merged from different vintages, from the Temblor Formation in the Coalinga heavy oil reservoir in the San Joaquin basin, California. The objective was identification, delineation, and demarcation of reservoir heterogeneities by seismostratigraphic and seismogeomorphic analysis. The proximity of the San Andreas Transforms greatly controlled basin evolution and caused substantial reservoir heterogeneity by changing the depositional environment from shallow marine to near-shore fluvial. Moreover, two unconformities dissect the reservoir interval. The seismic dataset exhibits erratic, distorted reflection strengths and amplitudes caused by steam-injection-aided production. A petrophysical analysis based on Gassmann fluid substitution suggests a 27% P-wave velocity decrease in steam-saturated intervals. Seismic to well log ties were problematic and vexing due to the resulting statics, wavelet changes, and line mismatches. Mapping and flattening on a deeper horizon, however, allowed mapping of the internal unconformities and well ties which were crucial for seismostratigraphic sequence identification. Visualization of seismic attributes brought out stratification patterns and two distinct, laterally and vertically extensive, porous, and interconnected facies tracts interpreted as incised valley fills and tidal-to-subtidal deposits as evidenced by bright, steam related amplitudes. Seismic attribute analysis, Geobody Visualization and Interpretation, and structure and isochron maps brought out two prominent channel-systems, recut and restacked in the central part of the area. These deposits were identified on seismic data and correlated to high-gamma coarsening-upward sands on logs and cores. The deeper one, shifting towards SSE with depth, lies between the Base Temblor and Buttonbed unconformities both in the southwestern and northwestern parts of

  5. Use of time series and harmonic constituents of tidal propagation to enhance estimation of coastal aquifer heterogeneity

    Science.gov (United States)

    Hughes, Joseph D.; White, Jeremy T.; Langevin, Christian D.

    2010-01-01

    A synthetic two‐dimensional model of a horizontally and vertically heterogeneous confined coastal aquifer system, based on the Upper Floridan aquifer in south Florida, USA, subjected to constant recharge and a complex tidal signal was used to generate 15‐minute water‐level data at select locations over a 7‐day simulation period.   “Observed” water‐level data were generated by adding noise, representative of typical barometric pressure variations and measurement errors, to 15‐minute data from the synthetic model. Permeability was calibrated using a non‐linear gradient‐based parameter inversion approach with preferred‐value Tikhonov regularization and 1) “observed” water‐level data, 2) harmonic constituent data, or 3) a combination of “observed” water‐level and harmonic constituent data.    In all cases, high‐frequency data used in the parameter inversion process were able to characterize broad‐scale heterogeneities; the ability to discern fine‐scale heterogeneity was greater when harmonic constituent data were used.  These results suggest that the combined use of highly parameterized‐inversion techniques and high frequency time and/or processed‐harmonic constituent water‐level data could be a useful approach to better characterize aquifer heterogeneities in coastal aquifers influenced by ocean tides.

  6. Spatial heterogeneity and seasonal succession of phytoplankton along the longitudinal gradient in a eutrophic reservoir

    Czech Academy of Sciences Publication Activity Database

    Rychtecký, Pavel; Znachor, Petr

    2011-01-01

    Roč. 663, č. 1 (2011), s. 175-186 ISSN 0018-8158 R&D Projects: GA ČR(CZ) GP206/07/P407; GA ČR(CZ) GA206/08/0015 Institutional research plan: CEZ:AV0Z60170517 Keywords : phytoplankton * reservoir * spatial heterogeneity * seasonal succession * functional classification * f lood event Subject RIV: DA - Hydrology ; Limnology Impact factor: 1.784, year: 2011

  7. Intermediate-Scale Experimental Study to Improve Fundamental Understanding of Attenuation Capacity for Leaking CO2 in Heterogeneous Shallow Aquifers

    Science.gov (United States)

    Plampin, Michael R.; Porter, Mark L.; Pawar, Rajesh J.; Illangasekare, Tissa H.

    2017-12-01

    To assess the risks of Geologic Carbon Sequestration (GCS), it is crucial to understand the fundamental physicochemical processes that may occur if and when stored CO2 leaks upward from a deep storage reservoir into the shallow subsurface. Intermediate-scale experiments allow for improved understanding of the multiphase evolution processes that control CO2 migration behavior in the subsurface, because the boundary conditions, initial conditions, and porous media parameters can be better controlled and monitored in the laboratory than in field settings. For this study, a large experimental test bed was designed to mimic a cross section of a shallow aquifer with layered geologic heterogeneity. As water with aqueous CO2 was injected into the system to mimic a CO2-charged water leakage scenario, the spatiotemporal evolution of the multiphase CO2 plume was monitored. Similar experiments were performed with two different sand combinations to assess the relative effects of different types of geologic facies transitions on the CO2 evolution processes. Significant CO2 attenuation was observed in both scenarios, but by fundamentally different mechanisms. When the porous media layers had very different permeabilities, attenuation was caused by local accumulation (structural trapping) and slow redissolution of gas phase CO2. When the permeability difference between the layers was relatively small, on the other hand, gas phase continually evolved over widespread areas near the leading edge of the aqueous plume, which also attenuated CO2 migration. This improved process understanding will aid in the development of models that could be used for effective risk assessment and monitoring programs for GCS projects.

  8. Phenanthrene sorption with heterogeneous organic matter in a landfill aquifer material

    Science.gov (United States)

    Karapanagioti, H.K.; Sabatini, D.A.; Kleineidam, S.; Grathwohl, P.; Ligouis, B.

    1999-01-01

    Phenanthrene was used as a model chemical to study the sorption properties of Canadian River Alluvium aquifer material. Both equilibrium and kinetic sorption processes were evaluated through batch studies. The bulk sample was divided into subsamples with varying properties such as particle size, organic content, equilibration time, etc. in order to determine the effect of these properties on resulting sorption parameters. The data have been interpreted and the effect of experimental variables was quantified using the Freundlich isotherm model and a numerical solution of Fick's 2nd law in porous media. Microscopic organic matter characterization proved to be a valuable tool for explaining the results. Different organic matter properties and sorption mechanisms were observed for each soil subsample. Samples containing coal particles presented high Koc values. Samples with organic matter dominated by organic coatings on quartz grains presented low Koc values and contained a high percentage of fast sorption sites. The numerical solution of Fick's 2ndlaw requires the addition of two terms (fast and slow) in order to fit the kinetics of these heterogeneous samples properly. These results thus demonstrate the need for soil organic matter characterization in order to predict and explain the sorption properties of a soil sample containing heterogeneous organic matter and also the difficulty and complexity of modeling sorption in such samples.

  9. Habitat heterogeneity on feeding habit of two sympatric and congeneric characidae fishes in two tropical reservoirs

    Directory of Open Access Journals (Sweden)

    Vanessa G. Lopes

    2016-01-01

    Full Text Available Abstract Food flexibility and omnivory are important features pronounced in Neotropical freshwater fish species, particularly for Astyanax species. Traditionally most fish diet resources are known to be originated in the aquatic environment, however recent studies have pointed to the importance of allochthonous sources. Besides, the colonization of macrophytes, common at several tropical reservoirs, may enhance insectivory in fish diet expanding or concentrating the area of available resources for feeding. Here we employed stomach contents analysis of two sympatric Astyanax species to access the importance of habitat differentiations as spatial complexity in two tropical reservoirs with different environmental features. The NMDS analysis indicated separation in the diet of these species between reservoirs (Stress= 8.28%. Additionally, analysis of variance revealed a significative difference in the volume of food itens ingested between the reservoirs (Anova one-way F(1, 132=4.4446; p= 0.037. This points out the importance of environmental conditions on the composition of the diet of fishes. This study highlighted the insectivorous feeding habit of Astyanax species and revealed different feeding strategies between sympatric fishes despite high niche overlap in both environments. Habitat heterogeneity increasing food resources availability plays an important role in the diet strategy of these Astyanax species and on their constant maintenance in the two different reservoirs.

  10. Integrated reservoir characterization: Improvement in heterogeneities stochastic modelling by integration of additional external constraints

    Energy Technology Data Exchange (ETDEWEB)

    Doligez, B.; Eschard, R. [Institut Francais du Petrole, Rueil Malmaison (France); Geffroy, F. [Centre de Geostatistique, Fontainebleau (France)] [and others

    1997-08-01

    The classical approach to construct reservoir models is to start with a fine scale geological model which is informed with petrophysical properties. Then scaling-up techniques allow to obtain a reservoir model which is compatible with the fluid flow simulators. Geostatistical modelling techniques are widely used to build the geological models before scaling-up. These methods provide equiprobable images of the area under investigation, which honor the well data, and which variability is the same than the variability computed from the data. At an appraisal phase, when few data are available, or when the wells are insufficient to describe all the heterogeneities and the behavior of the field, additional constraints are needed to obtain a more realistic geological model. For example, seismic data or stratigraphic models can provide average reservoir information with an excellent areal coverage, but with a poor vertical resolution. New advances in modelisation techniques allow now to integrate this type of additional external information in order to constrain the simulations. In particular, 2D or 3D seismic derived information grids, or sand-shale ratios maps coming from stratigraphic models can be used as external drifts to compute the geological image of the reservoir at the fine scale. Examples are presented to illustrate the use of these new tools, their impact on the final reservoir model, and their sensitivity to some key parameters.

  11. Model-based analysis of δ34S signatures to trace sedimentary pyrite oxidation during managed aquifer recharge in a heterogeneous aquifer

    Science.gov (United States)

    Seibert, Simone; Descourvieres, Carlos; Skrzypek, Grzegorz; Deng, Hailin; Prommer, Henning

    2017-05-01

    The oxidation of pyrite is often one of the main drivers affecting groundwater quality during managed aquifer recharge in deep aquifers. Data and techniques that allow detailed identification and quantification of pyrite oxidation are therefore crucial for assessing and predicting the adverse water quality changes that may be associated with this process. In this study, we explore the benefits of combining stable sulphur isotope analysis with reactive transport modelling to improve the identification and characterisation of pyrite oxidation during an aquifer storage and recovery experiment in a chemically and physically heterogeneous aquifer. We characterise the stable sulphur isotope signal (δ34S) in both the ambient groundwater and the injectant as well as its spatial distribution within the sedimentary sulphur species. The identified stable sulphur isotope signal for pyrite was found to vary between -32 and +34‰, while the signal of the injectant ranged between +9.06 and +14.45‰ during the injection phase of the experiment. Both isotope and hydrochemical data together suggest a substantial contribution of pyrite oxidation to the observed, temporally variable δ34S signals. The variability of the δ34S signal in pyrite and the injectant were both found to complicate the analysis of the stable isotope data. However, the incorporation of the data into a numerical modelling approach allowed to successfully employ the δ34S signatures as a valuable additional constraint for identifying and quantifying the contribution of pyrite oxidation to the redox transformations that occur in response to the injection of oxygenated water.

  12. Quantifying Fracture Heterogeneity in Different Domains of Folded Carbonate Rocks to Improve Fractured Reservoir Analog Fluid Flow Models

    NARCIS (Netherlands)

    Bisdom, K.; Bertotti, G.; Gauthier, B.D.M.; Hardebol, N.J.

    2013-01-01

    Fluid flow in carbonate reservoirs is largely controlled by multiscale fracture networks. Significant variations of fracture network porosity and permeability are caused by the 3D heterogeneity of the fracture network characteristics, such as intensity, orientation and size. Characterizing fracture

  13. Well-Production Data and Gas-Reservoir Heterogeneity -- Reserve Growth Applications

    Science.gov (United States)

    Dyman, Thaddeus S.; Schmoker, James W.

    2003-01-01

    Oil and gas well production parameters, including peakmonthly production (PMP), peak-consecutive-twelve month production (PYP), and cumulative production (CP), are tested as tools to quantify and understand the heterogeneity of reservoirs in fields where current monthly production is 10 percent or less of PMP. Variation coefficients, defined as VC= (F5-F95)/F50, where F5, F95, and F50 are the 5th, 95th, and 50th (median) fractiles of a probability distribution, are calculated for peak and cumulative production and examined with respect to internal consistency, type of production parameter, conventional versus unconventional accumulations, and reservoir depth. Well-production data for this study were compiled for 69 oil and gas fields in the Lower Pennsylvanian Morrow Formation of the Anadarko Basin, Oklahoma. Of these, 47 fields represent production from marine clastic facies. The Morrow data were supplemented by data from the Upper Cambrian and Lower Ordovician Arbuckle Group, Middle Ordovician Simpson Group, Middle Pennsylvanian Atoka Formation, and Silurian and Lower Devonian Hunton Group of the Anadarko Basin, one large gas field in Upper Cretaceous reservoirs of north-central Montana (Bowdoin field), and three areas of the Upper Devonian and Lower Mississippian Bakken Formation continuous-type (unconventional) oil accumulation in the Williston Basin, North Dakota and Montana. Production parameters (PMP, PYP, and CP) measure the net result of complex geologic, engineering, and economic processes. Our fundamental hypothesis is that well-production data provide information about subsurface heterogeneity in older fields that would be impossible to obtain using geologic techniques with smaller measurement scales such as petrographic, core, and well-log analysis. Results such as these indicate that quantitative measures of production rates and production volumes of wells, expressed as dimensionless variation coefficients, are potentially valuable tools for

  14. Conditioning geostatistical simulations of a heterogeneous paleo-fluvial bedrock aquifer using lithologs and pumping tests

    Science.gov (United States)

    Niazi, A.; Bentley, L. R.; Hayashi, M.

    2016-12-01

    Geostatistical simulations are used to construct heterogeneous aquifer models. Optimally, such simulations should be conditioned with both lithologic and hydraulic data. We introduce an approach to condition lithologic geostatistical simulations of a paleo-fluvial bedrock aquifer consisting of relatively high permeable sandstone channels embedded in relatively low permeable mudstone using hydraulic data. The hydraulic data consist of two-hour single well pumping tests extracted from the public water well database for a 250-km2 watershed in Alberta, Canada. First, lithologic models of the entire watershed are simulated and conditioned with hard lithological data using transition probability - Markov chain geostatistics (TPROGS). Then, a segment of the simulation around a pumping well is used to populate a flow model (FEFLOW) with either sand or mudstone. The values of the hydraulic conductivity and specific storage of sand and mudstone are then adjusted to minimize the difference between simulated and actual pumping test data using the parameter estimation program PEST. If the simulated pumping test data do not adequately match the measured data, the lithologic model is updated by locally deforming the lithology distribution using the probability perturbation method and the model parameters are again updated with PEST. This procedure is repeated until the simulated and measured data agree within a pre-determined tolerance. The procedure is repeated for each well that has pumping test data. The method creates a local groundwater model that honors both the lithologic model and pumping test data and provides estimates of hydraulic conductivity and specific storage. Eventually, the simulations will be integrated into a watershed-scale groundwater model.

  15. Evaluation of Microstructural Parameters of Reservoir Rocks of the Guarani Aquifer by Analysis of Images Obtained by X- Ray Microtomography

    International Nuclear Information System (INIS)

    Fernandes, J S; Lima, F A; Vieira, S F; Reis, P J; Appoloni, C R

    2015-01-01

    Microstructural parameters evaluation of porous materials, such as, rocks reservoir (water, petroleum, gas...), it is of great importance for several knowledge areas. In this context, the X-ray microtomography (μ-CT) has been showing a technical one quite useful for the analysis of such rocks (sandstone, limestone and carbonate), object of great interest of the petroleum and water industries, because it facilitates the characterization of important parameters, among them, porosity, permeability, grains or pore size distribution. The X-ray microtomography is a non-destructive method, that besides already facilitating the reuse of the samples analyzed, it also supplies images 2-D and 3-D of the sample. In this work samples of reservoir rock of the Guarani aquifer will be analyzed, given by the company of perforation of wells artesian Blue Water, in the municipal district of Videira, Santa Catarina, Brazil. The acquisition of the microtomographys data of the reservoir rocks was accomplished in a Skyscan 1172 μ-CT scanner, installed in Applied Nuclear Physics Laboratory (LFNA) in the State University of Londrina (UEL), Paraná, Brazil. In this context, this work presents the microstructural characterization of reservoir rock sample of the Guarani aquifer, analyzed for two space resolutions, 2.8 μm and 4.8 μm, where determined average porosity was 28.5% and 21.9%, respectively. Besides, we also determined the pore size distribution for both resolutions. Two 3-D images were generated of this sample, one for each space resolution, in which it is possible to visualize the internal structure of the same ones. (paper)

  16. Evaluation of Microstructural Parameters of Reservoir Rocks of the Guarani Aquifer by Analysis of Images Obtained by X- Ray Microtomography

    Science.gov (United States)

    Fernandes, J. S.; Lima, F. A.; Vieira, S. F.; Reis, P. J.; Appoloni, C. R.

    2015-07-01

    Microstructural parameters evaluation of porous materials, such as, rocks reservoir (water, petroleum, gas...), it is of great importance for several knowledge areas. In this context, the X-ray microtomography (μ-CT) has been showing a technical one quite useful for the analysis of such rocks (sandstone, limestone and carbonate), object of great interest of the petroleum and water industries, because it facilitates the characterization of important parameters, among them, porosity, permeability, grains or pore size distribution. The X-ray microtomography is a non-destructive method, that besides already facilitating the reuse of the samples analyzed, it also supplies images 2-D and 3-D of the sample. In this work samples of reservoir rock of the Guarani aquifer will be analyzed, given by the company of perforation of wells artesian Blue Water, in the municipal district of Videira, Santa Catarina, Brazil. The acquisition of the microtomographys data of the reservoir rocks was accomplished in a Skyscan 1172 μ-CT scanner, installed in Applied Nuclear Physics Laboratory (LFNA) in the State University of Londrina (UEL), Paraná, Brazil. In this context, this work presents the microstructural characterization of reservoir rock sample of the Guarani aquifer, analyzed for two space resolutions, 2.8 μm and 4.8 μm, where determined average porosity was 28.5% and 21.9%, respectively. Besides, we also determined the pore size distribution for both resolutions. Two 3-D images were generated of this sample, one for each space resolution, in which it is possible to visualize the internal structure of the same ones.

  17. Analytical Model of Waterflood Sweep Efficiency in Vertical Heterogeneous Reservoirs under Constant Pressure

    Directory of Open Access Journals (Sweden)

    Lisha Zhao

    2016-01-01

    Full Text Available An analytical model has been developed for quantitative evaluation of vertical sweep efficiency based on heterogeneous multilayer reservoirs. By applying the Buckley-Leverett displacement mechanism, a theoretical relationship is deduced to describe dynamic changes of the front of water injection, water saturation of producing well, and swept volume during waterflooding under the condition of constant pressure, which substitutes for the condition of constant rate in the traditional way. Then, this method of calculating sweep efficiency is applied from single layer to multilayers, which can be used to accurately calculate the sweep efficiency of heterogeneous reservoirs and evaluate the degree of waterflooding in multilayer reservoirs. In the case study, the water frontal position, water cut, volumetric sweep efficiency, and oil recovery are compared between commingled injection and zonal injection by applying the derived equations. The results are verified by numerical simulators, respectively. It is shown that zonal injection works better than commingled injection in respect of sweep efficiency and oil recovery and has a longer period of water free production.

  18. Method of improving heterogeneous oil reservoir polymer flooding effect by positively-charged gel profile control

    Science.gov (United States)

    Zhao, Ling; Xia, Huifen

    2018-01-01

    The project of polymer flooding has achieved great success in Daqing oilfield, and the main oil reservoir recovery can be improved by more than 15%. But, for some strong oil reservoir heterogeneity carrying out polymer flooding, polymer solution will be inefficient and invalid loop problem in the high permeability layer, then cause the larger polymer volume, and a significant reduction in the polymer flooding efficiency. Aiming at this problem, it is studied the method that improves heterogeneous oil reservoir polymer flooding effect by positively-charged gel profile control. The research results show that the polymer physical and chemical reaction of positively-charged gel with the residual polymer in high permeability layer can generate three-dimensional network of polymer, plugging high permeable layer, and increase injection pressure gradient, then improve the effect of polymer flooding development. Under the condition of the same dosage, positively-charged gel profile control can improve the polymer flooding recovery factor by 2.3∼3.8 percentage points. Under the condition of the same polymer flooding recovery factor increase value, after positively-charged gel profile control, it can reduce the polymer volume by 50 %. Applying mechanism of positively-charged gel profile control technology is feasible, cost savings, simple construction, and no environmental pollution, therefore has good application prospect.

  19. Impact of aquifer heterogeneity structure and local-scale dispersion on solute concentration uncertainty

    Science.gov (United States)

    Srzic, Veljko; Cvetkovic, Vladimir; Andricevic, Roko; Gotovac, Hrvoje

    2013-06-01

    In this paper, we study the influence of high log-conductivity variance (σY2) and local-scale dispersion on the first two concentration moments as well as on higher-order moments, skewness, and kurtosis, in a 2-D heterogeneous aquifer. Three different heterogeneity structures are considered, defined with one and the same global isotropic Gaussian variogram. The three structures differ in terms of spatial connectivity patterns at extreme log-conductivity values. Our numerical approach to simulate contaminant transport through heterogeneous porous media is based on the Lagrangian framework with a reverse tracking formulation. Advection and local-scale dispersion are two competing and controlling mechanisms, with a relative ratio defined by the Peclet number (Pe); hydraulic log-conductivity variance σY2 in the simulations is assumed to be one or eight. The term local-scale dispersion is used as a combined effect of molecular diffusion and mechanical dispersion. Uncertainty of the concentration field is quantified by the second-order moment, or the coefficient of variation (CVC) as a function of the sampling position along a centerline, Peclet number, and σY2, as well as by higher-order moments, i.e., skewness and kurtosis. The parameter σY2 shows a strong influence on the concentration statistics, while the three different structures have a minor impact in the case of low heterogeneity. The results also indicate that for σY2=8, the influence of local-scale dispersion is significant after five integral scales (IY) from the source for the connected (CN) field, while in case of a disconnected field, the local-scale dispersion effect is observed after 20IY from the source. In the case of unit σY2, local-scale dispersion acts very slowly affecting concentration uncertainty at distances higher than 20IY from the source. Our inspection of Monte Carlo concentration skewness and kurtosis with the ones obtained from the Beta distribution show the discrepancies for high

  20. Characterization of oil and gas reservoir heterogeneity; Final report, November 1, 1989--June 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, G.D.

    1993-09-01

    The Alaskan North Slope comprises one of the Nation`s and the world`s most prolific oil province. Original oil in place (OOIP) is estimated at nearly 70 BBL (Kamath and Sharma, 1986). Generalized reservoir descriptions have been completed by the University of Alaska`s Petroleum Development Laboratory over North Slope`s major fields. These fields include West Sak (20 BBL OOIP), Ugnu (15 BBL OOIP), Prudhoe Bay (23 BBL OOIP), Kuparuk (5.5 BBL OOIP), Milne Point (3 BBL OOIP), and Endicott (1 BBL OOIP). Reservoir description has included the acquisition of open hole log data from the Alaska Oil and Gas Conservation Commission (AOGCC), computerized well log analysis using state-of-the-art computers, and integration of geologic and logging data. The studies pertaining to fluid characterization described in this report include: experimental study of asphaltene precipitation for enriched gases, CO{sup 2} and West Sak crude system, modeling of asphaltene equilibria including homogeneous as well as polydispersed thermodynamic models, effect of asphaltene deposition on rock-fluid properties, fluid properties of some Alaskan north slope reservoirs. Finally, the last chapter summarizes the reservoir heterogeneity classification system for TORIS and TORIS database.

  1. Fine-Scale Spatial Heterogeneity in the Distribution of Waterborne Protozoa in a Drinking Water Reservoir.

    Science.gov (United States)

    Burnet, Jean-Baptiste; Ogorzaly, Leslie; Penny, Christian; Cauchie, Henry-Michel

    2015-09-23

    The occurrence of faecal pathogens in drinking water resources constitutes a threat to the supply of safe drinking water, even in industrialized nations. To efficiently assess and monitor the risk posed by these pathogens, sampling deserves careful design, based on preliminary knowledge on their distribution dynamics in water. For the protozoan pathogens Cryptosporidium and Giardia, only little is known about their spatial distribution within drinking water supplies, especially at fine scale. Two-dimensional distribution maps were generated by sampling cross-sections at meter resolution in two different zones of a drinking water reservoir. Samples were analysed for protozoan pathogens as well as for E. coli, turbidity and physico-chemical parameters. Parasites displayed heterogeneous distribution patterns, as reflected by significant (oo)cyst density gradients along reservoir depth. Spatial correlations between parasites and E. coli were observed near the reservoir inlet but were absent in the downstream lacustrine zone. Measurements of surface and subsurface flow velocities suggest a role of local hydrodynamics on these spatial patterns. This fine-scale spatial study emphasizes the importance of sampling design (site, depth and position on the reservoir) for the acquisition of representative parasite data and for optimization of microbial risk assessment and monitoring. Such spatial information should prove useful to the modelling of pathogen transport dynamics in drinking water supplies.

  2. Integrated reservoir characterization of a heterogeneous channel sandstone : the Duchess Lower Manville X pool

    Energy Technology Data Exchange (ETDEWEB)

    Potocki, D.; Raychaudhuri, I.; Thorburn, L. [PanCanadian Petroleum Ltd. (Canada); Galas, C.; King, H.

    1999-01-01

    The Basal Quartz formation of the Duchess Lower Mannville X pool located in southern Alberta was characterized to determine if the reservoir was a good candidate for waterflooding. Twenty performance predictions were run. The Basal Quartz reservoir sandstones have large unanticipated intrawell and interwell variations in log derived porosity and resistivity. An extensive gas cap was also found in most of the wells. Most wells were producing with a high GOR despite the thick oil zone. It was concluded that conversion of selected wells to injection and horizontal infill wells would increase the oil recovery, but due to geological heterogeneity, the gas cap and a high in situ oil viscosity, the pool could not be considered to be a good candidate for waterflooding. 3 refs., 12 figs.

  3. How does layered heterogeneity affect the ability of subsurface dams to clean up coastal aquifers contaminated with seawater intrusion?

    Science.gov (United States)

    Abdoulhalik, Antoifi; Ahmed, Ashraf A.

    2017-10-01

    The main purpose of this work was to examine how aquifer layering impacts the ability of subsurface dams to retain seawater intrusion (SWI) and to clean up contaminated coastal aquifers using both experimental and numerical techniques. Four different layering configurations were investigated, including a homogeneous case (case H), and three different layered cases where a low permeability layer was set at the top of the aquifer (case LH), at the middle part of the aquifer as interlayer (case HLH), and at the lower part of the aquifer (case HL). The subsurface dam was able to retain the saltwater wedge associated with a drop of the hydraulic gradient from 0.0158 down to 0.0095 in all the cases, thereby achieving up to 78% reduction in the saltwater toe length. In cases LH and HLH, the start of the saltwater spillage was delayed compared to the homogeneous case, and the time taken for the freshwater zone to be fully contaminated (post-spillage) was twice and three times longer, respectively. By contrast, the existence of a low K layer at the bottom of the aquifer (case HL) considerably weakened the ability of dams to retain the intrusion, allowing for quicker saltwater spillage past the wall. The natural cleanup of SWI-contaminated coastal aquifers was, for the first time, evidenced in heterogeneous settings. Depending on the stratification pattern, the presence of stratified layers however prolonged the cleanup time to various degrees, compared to the homogeneous scenario, particularly in case HL, where the cleanup time was nearly 50% longer.

  4. Impact of sub-horizontal discontinuities and vertical heterogeneities on recharge processes in a weathered crystalline aquifer in southern India

    Science.gov (United States)

    Nicolas, Madeleine; Selles, Adrien; Bour, Olivier; Maréchal, Jean-Christophe; Crenner, Marion; Wajiduddin, Mohammed; Ahmed, Shakeel

    2017-04-01

    In the face of increasing demands for irrigated agriculture, many states in India are facing water scarcity issues, leading to severe groundwater depletion. Because perennial water resources in southern India consist mainly of crystalline aquifers, understanding how recharge takes place and the role of preferential flow zones in such heterogeneous media is of prime importance for successful and sustainable aquifer management. Here we investigate how vertical heterogeneities and highly transmissive sub-horizontal discontinuities may control groundwater flows and recharge dynamics. Recharge processes in the vadose zone were examined by analysing the propagation of an infiltration front and mass transfers resulting from the implementation of a managed aquifer recharge (MAR) structure. Said structure was set up in the Experimental Hydrogeological Park in Telangana (Southern India), a well-equipped and continuously monitored site, which is periodically supplied with surface water deviated from the nearby Musi river, downstream of Hyderabad. An initial volume balance equation was applied to quantify the overall inputs from the MAR structure into the groundwater system, which was confirmed using a chloride mass balance approach. To understand how this incoming mass is then distributed within the aquifer, we monitored the evolution of water volumes in the tank, and the resulting lateral propagation front observed in the surrounding borehole network. Borehole logs of temperature and conductivity were regularly performed to identify preferential flow paths. As a result we observed that mass transfers take place in the way of preferential lateral flow through the most transmissive zones of the profile. These include the interface between the lower portion of the upper weathered horizon (the saprolite) and the upper part of the underlying fissured granite, as well as the first flowing fractures. This leads to a rapid lateral transfer of recharge, which allows quick

  5. Reservoir characterization and final pre-test analysis in support of the compressed-air-energy-storage Pittsfield aquifer field test in Pike County, Illinois

    Energy Technology Data Exchange (ETDEWEB)

    Wiles, L.E.; McCann, R.A.

    1983-06-01

    The work reported is part of a field experimental program to demonstrate and evaluate compressed air energy storage in a porous media aquifer reservoir near Pittsfield, Illinois. The reservoir is described. Numerical modeling of the reservoir was performed concurrently with site development. The numerical models were applied to predict the thermohydraulic performance of the porous media reservoir. This reservoir characterization and pre-test analysis made use of evaluation of bubble development, water coning, thermal development, and near-wellbore desaturation. The work was undertaken to define the time required to develop an air storage bubble of adequate size, to assess the specification of instrumentation and above-ground equipment, and to develop and evaluate operational strategies for air cycling. A parametric analysis was performed for the field test reservoir. (LEW)

  6. Predicting Formation Damage in Aquifer Thermal Energy Storage Systems Utilizing a Coupled Hydraulic-Thermal-Chemical Reservoir Model

    Science.gov (United States)

    Müller, Daniel; Regenspurg, Simona; Milsch, Harald; Blöcher, Guido; Kranz, Stefan; Saadat, Ali

    2014-05-01

    In aquifer thermal energy storage (ATES) systems, large amounts of energy can be stored by injecting hot water into deep or intermediate aquifers. In a seasonal production-injection cycle, water is circulated through a system comprising the porous aquifer, a production well, a heat exchanger and an injection well. This process involves large temperature and pressure differences, which shift chemical equilibria and introduce or amplify mechanical processes. Rock-fluid interaction such as dissolution and precipitation or migration and deposition of fine particles will affect the hydraulic properties of the porous medium and may lead to irreversible formation damage. In consequence, these processes determine the long-term performance of the ATES system and need to be predicted to ensure the reliability of the system. However, high temperature and pressure gradients and dynamic feedback cycles pose challenges on predicting the influence of the relevant processes. Within this study, a reservoir model comprising a coupled hydraulic-thermal-chemical simulation was developed based on an ATES demonstration project located in the city of Berlin, Germany. The structural model was created with Petrel, based on data available from seismic cross-sections and wellbores. The reservoir simulation was realized by combining the capabilities of multiple simulation tools. For the reactive transport model, COMSOL Multiphysics (hydraulic-thermal) and PHREEQC (chemical) were combined using the novel interface COMSOL_PHREEQC, developed by Wissmeier & Barry (2011). It provides a MATLAB-based coupling interface between both programs. Compared to using COMSOL's built-in reactive transport simulator, PHREEQC additionally calculates adsorption and reaction kinetics and allows the selection of different activity coefficient models in the database. The presented simulation tool will be able to predict the most important aspects of hydraulic, thermal and chemical transport processes relevant to

  7. Scale-up of miscible flood processes for heterogeneous reservoirs. 1993 annual report

    Energy Technology Data Exchange (ETDEWEB)

    Orr, F.M. Jr.

    1994-05-01

    Progress is reported for a comprehensive investigation of the scaling behavior of gas injection processes in heterogeneous reservoirs. The interplay of phase behavior, viscous fingering, gravity segregation, capillary imbibition and drainage, and reservoir heterogeneity is examined in a series of simulations and experiments. Compositional and first-contact miscable simulations of viscous fingering and gravity segregation are compared to show that the two techniques can give very different results. Also, analyzed are two-dimensional and three-dimensional flows in which gravity segregation and viscous fingering interact. The simulations show that 2D and 3D flows can differ significantly. A comparison of analytical solutions for three-component two-phase flow with experimental results for oil/water/alcohol systems is reported. While the experiments and theory show reasonable agreement, some differences remain to be explained. The scaling behavior of the interaction of gravity segregation and capillary forces is investigated through simulations and through scaling arguments based on analysis of the differential equations. The simulations show that standard approaches do not agree well with results of low IFT displacements. The scaling analyses, however, reveal flow regimes where capillary, gravity, or viscous forces dominate the flow.

  8. Potential water supply of a small reservoir and alluvial aquifer system in southern Zimbabwe

    NARCIS (Netherlands)

    de Hamer, W.; Love, D.; Owen, R.; Booij, Martijn J.; Hoekstra, Arjen Ysbert

    2008-01-01

    Groundwater use by accessing alluvial aquifers of non-perennial rivers can be an important additional water resource in the semi-arid region of southern Zimbabwe. The research objective of the study was to calculate the potential water supply for the upper-Mnyabezi catchment under current conditions

  9. Measurement and modeling of CO2 diffusion coefficient in Saline Aquifer at reservoir conditions

    Science.gov (United States)

    Azin, Reza; Mahmoudy, Mohamad; Raad, Seyed; Osfouri, Shahriar

    2013-12-01

    Storage of CO2 in deep saline aquifers is a promising techniques to mitigate global warming and reduce greenhouse gases (GHG). Correct measurement of diffusivity is essential for predicting rate of transfer and cumulative amount of trapped gas. Little information is available on diffusion of GHG in saline aquifers. In this study, diffusivity of CO2 into a saline aquifer taken from oil field was measured and modeled. Equilibrium concentration of CO2 at gas-liquid interface was determined using Henry's law. Experimental measurements were reported at temperature and pressure ranges of 32-50°C and 5900-6900 kPa, respectively. Results show that diffusivity of CO2 varies between 3.52-5.98×10-9 m2/s for 5900 kPa and 5.33-6.16×10-9 m2/s for 6900 kPa initial pressure. Also, it was found that both pressure and temperature have a positive impact on the measures of diffusion coefficient. Liquid swelling due to gas dissolution and variations in gas compressibility factor as a result of pressure decay was found negligible. Measured diffusivities were used model the physical model and develop concentration profile of dissolved gas in the liquid phase. Results of this study provide unique measures of CO2 diffusion coefficient in saline aquifer at high pressure and temperature conditions, which can be applied in full-field studies of carbon capture and sequestration projects.

  10. Spatial connectivity in a highly heterogeneous aquifer: From cores to preferential flow paths

    Science.gov (United States)

    Bianchi, M.; Zheng, C.; Wilson, C.; Tick, G.R.; Liu, Gaisheng; Gorelick, S.M.

    2011-01-01

    This study investigates connectivity in a small portion of the extremely heterogeneous aquifer at the Macrodispersion Experiment (MADE) site in Columbus, Mississippi. A total of 19 fully penetrating soil cores were collected from a rectangular grid of 4 m by 4 m. Detailed grain size analysis was performed on 5 cm segments of each core, yielding 1740 hydraulic conductivity (K) estimates. Three different geostatistical simulation methods were used to generate 3-D conditional realizations of the K field for the sampled block. Particle tracking calculations showed that the fastest particles, as represented by the first 5% to arrive, converge along preferential flow paths and exit the model domain within preferred areas. These 5% fastest flow paths accounted for about 40% of the flow. The distribution of preferential flow paths and particle exit locations is clearly influenced by the occurrence of clusters formed by interconnected cells with K equal to or greater than the 0.9 decile of the data distribution (10% of the volume). The fraction of particle paths within the high-K clusters ranges from 43% to 69%. In variogram-based K fields, some of the fastest paths are through media with lower K values, suggesting that transport connectivity may not require fully connected zones of relatively homogenous K. The high degree of flow and transport connectivity was confirmed by the values of two groups of connectivity indicators. In particular, the ratio between effective and geometric mean K (on average, about 2) and the ratio between the average arrival time and the arrival time of the fastest particles (on average, about 9) are consistent with flow and advective transport behavior characterized by channeling along preferential flow paths. ?? 2011 by the American Geophysical Union.

  11. Approaches to identifying reservoir heterogeneity and reserve growth opportunities from subsurface data: The Oficina Formation, Budare field, Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, D.S.; Raeuchle, S.K.; Holtz, M.H. [Bureau of Economic Geology, Austin, TX (United States)] [and others

    1997-08-01

    We applied an integrated geologic, geophysical, and engineering approach devised to identify heterogeneities in the subsurface that might lead to reserve growth opportunities in our analysis of the Oficina Formation at Budare field, Venezuela. The approach involves 4 key steps: (1) Determine geologic reservoir architecture; (2) Investigate trends in reservoir fluid flow; (3) Integrate fluid flow trends with reservoir architecture; and (4) Estimate original oil-in-place, residual oil saturation, and remaining mobile oil, to identify opportunities for reserve growth. There are three main oil-producing reservoirs in the Oficina Formation that were deposited in a bed-load fluvial system, an incised valley-fill, and a barrier-strandplain system. Reservoir continuity is complex because, in addition to lateral facies variability, the major Oficina depositional systems were internally subdivided by high-frequency stratigraphic surfaces. These surfaces define times of intermittent lacustrine and marine flooding events that punctuated the fluvial and marginal marine sedimentation, respectively. Syn and post depositional faulting further disrupted reservoir continuity. Trends in fluid flow established from initial fluid levels, response to recompletion workovers, and pressure depletion data demonstrated barriers to lateral and vertical fluid flow caused by a combination of reservoir facies pinchout, flooding shale markers, and the faults. Considerable reserve growth potential exists at Budare field because the reservoir units are highly compartment by the depositional heterogeneity and structural complexity. Numerous reserve growth opportunities were identified in attics updip of existing production, in untapped or incompletely drained compartments, and in field extensions.

  12. A frequency domain analysis to characterize heterogeneity and recharge mechanisms in a fractured crystalline-rock aquifer

    Science.gov (United States)

    Jimenez-Martinez, J.; Longuevergne, L.; Le Borgne, T.; Davy, P.; Bour, O.; Goderniaux, P.; Russian, A.; Thomas, Z.

    2011-12-01

    We investigate aquifer behavior and recharge mechanisms in fracture media using a frequency domain approach. Main interest was the quantification of aquifer characteristic time response, storativity and estimation of heterogeneity and connectivity impact on well behavior on a wide range of temporal scales from 1 day to 8 years. Transfer Functions were calculated for a fractured crystalline-rock aquifer system located in Ploemeur (S of Brittany, France). Recharge, first calculated as effective rainfall, and groundwater level fluctuations (tide effects removed) were used as input and output functions, respectively. The Transfer Function quantifies the ratio of amplitudes of the input and output in the frequency domain. The obtained transfer functions are typically constant at low frequency and decay with frequency for mid and high frequencies. Classical behavior models for interpreting transfer functions are the linear and Dupuit models, plus combination with fast flow component. For linear and Dupuit models, the transfer function |H(ω)|2 scales respectively as |H(ω)|2 ~ ω-2, and |H(ω)|2 ~ ω-1 for high frequencies. The transfer functions obtained for the fractured rock aquifer of Ploemeur do not follow these scaling. Instead, they scale as |H(ω)|2 ~ ω-β, with β=0.7. This suggests that the heterogeneity at different scales in this fractured system involves a variety of transfer processes that cannot be represented by classical models. We discuss the relevance of alternative dual-permeability and multi-permeability models for modeling the rainfall-hydraulic head response in this fractured media. We analyze the variability of the response (characteristic time, amplitude and asymptotic log-log slope) for wells intersecting the main fracture zone, intersecting secondary fracture zones or located in weathered rock.

  13. Measuring and predicting reservoir heterogeneity in complex deposystems: The fluvial-deltaic Big Injun sandstone in West Virginia

    Energy Technology Data Exchange (ETDEWEB)

    Patchen, D.G.; Hohn, M.E.; Aminian, K.; Donaldson, A.; Shumaker, R.; Wilson, T.

    1993-04-01

    The purpose of this research is to develop techniques to measure and predict heterogeneities in oil reservoirs that are the products of complex deposystems. The unit chosen for study is the Lower Mississippian Big Injun sandstone, a prolific oil producer (nearly 60 fields) in West Virginia. This research effort has been designed and is being implemented as an integrated effort involving stratigraphy, structural geology, petrology, seismic study, petroleum engineering, modeling and geostatistics. Sandstone bodies are being mapped within their regional depositional systems, and then sandstone bodies are being classified in a scheme of relative heterogeneity to determine heterogeneity across depositional systems. Facies changes are being mapped within given reservoirs, and the environments of deposition responsible for each facies are being interpreted to predict the inherent relative heterogeneity of each facies. Structural variations will be correlated both with production, where the availability of production data will permit, and with variations in geologic and engineering parameters that affect production. A reliable seismic model of the Big Injun reservoirs in Granny Creek field is being developed to help interpret physical heterogeneity in that field. Pore types are being described and related to permeability, fluid flow and diagenesis, and petrographic data are being integrated with facies and depositional environments to develop a technique to use diagenesis as a predictive tool in future reservoir development. Another objective in the Big Injun study is to determine the effect of heterogeneity on fluid flow and efficient hydrocarbon recovery in order to improve reservoir management. Graphical methods will be applied to Big Injun production data and new geostatistical methods will be developed to detect regional trends in heterogeneity.

  14. Stochastic analysis of the efficiency of coupled hydraulic-physical barriers to contain solute plumes in highly heterogeneous aquifers

    Science.gov (United States)

    Pedretti, Daniele; Masetti, Marco; Beretta, Giovanni Pietro

    2017-10-01

    The expected long-term efficiency of vertical cutoff walls coupled to pump-and-treat technologies to contain solute plumes in highly heterogeneous aquifers was analyzed. A well-characterized case study in Italy, with a hydrogeological database of 471 results from hydraulic tests performed on the aquifer and the surrounding 2-km-long cement-bentonite (CB) walls, was used to build a conceptual model and assess a representative remediation site adopting coupled technologies. In the studied area, the aquifer hydraulic conductivity Ka [m/d] is log-normally distributed with mean E (Ya) = 0.32 , variance σYa2 = 6.36 (Ya = lnKa) and spatial correlation well described by an exponential isotropic variogram with integral scale less than 1/12 the domain size. The hardened CB wall's hydraulic conductivity, Kw [m/d], displayed strong scaling effects and a lognormal distribution with mean E (Yw) = - 3.43 and σYw2 = 0.53 (Yw =log10Kw). No spatial correlation of Kw was detected. Using this information, conservative transport was simulated across a CB wall in spatially correlated 1-D random Ya fields within a numerical Monte Carlo framework. Multiple scenarios representing different Kw values were tested. A continuous solute source with known concentration and deterministic drains' discharge rates were assumed. The efficiency of the confining system was measured by the probability of exceedance of concentration over a threshold (C∗) at a control section 10 years after the initial solute release. It was found that the stronger the aquifer heterogeneity, the higher the expected efficiency of the confinement system and the lower the likelihood of aquifer pollution. This behavior can be explained because, for the analyzed aquifer conditions, a lower Ka generates more pronounced drawdown in the water table in the proximity of the drain and consequently a higher advective flux towards the confined area, which counteracts diffusive fluxes across the walls. Thus, a higher σYa2 results

  15. Spatial and temporal heterogeneity in a subtropical reservoir and their effects over the benthic macroinvertebrate community

    Directory of Open Access Journals (Sweden)

    Frederico Guilherme de Souza Beghelli

    2014-09-01

    Full Text Available AIM: The objective of the present study was to demonstrate the influences of the environment spatial heterogeneity on benthic macroinvertebrates considering transverse and longitudinal gradients as also seasonality. METHODS: Four samplings were performed: two in the wet and two in the dry season in the riverine, transitional and lacustrine zones in the littoral and profundal regions of Itupararanga reservoir, SP, Brazil. Abiotic characterization of the water and of the sediment was performed. The biotic characterization was based on richness, dominance, diversity, and density of organisms, as well as on the relative abundance of predominant taxa. Two-way ANOSIM analyses were performed for both biotic and abiotic components, in order to test the significance of the differences in the longitudinal and transverse directions as well as of the differences between seasons. RESULTS: Compartmentalization was present in both directions, longitudinal and transverse. In a general way, the littoral region presented higher diversity values when compared with the profundal region, and the riverine zone presented high densities and high percentage of taxons, which usually indicate organic pollution. The differentiation between the transitional and lacustrine zones was determined mainly by taxonomic composition. Seasonality was also observed and the transportation of small particles, the entrance of nutrients, and the presence of macrophytes were considered as determinants for differentiation. CONCLUSIONS: Together, these results demonstrate the responses of benthic macroinvertebrate communities considering distinct sources of variation: longitudinal heterogeneity, determined by the increasing distance from the forming rivers that leads to a gradient of physical and chemical conditions; transverse heterogeneity, determined by the proximity with the land environment and depth differences. Seasonal heterogeneity was recorded during the period of this research and

  16. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Franklin M. Orr, Jr.

    2002-06-30

    This report outlines progress in the third quarter of the second year of the DOE project ''High Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs''. High order finite difference schemes for one-dimensional, two-phase, multicomponent displacements are investigated. Numerical tests are run using a three component fluid description for a case when the interaction between phase behavior and flow is strong. Some currently used total variation diminishing (TVD) methods produce unstable results. A third order essentially non-oscillatory (ENO) method captures the effects of phase behavior for this test case. Possible modifications to ensure stability are discussed along with plans to incorporate higher order schemes into the 3DSL streamline simulator.

  17. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Franklin M. Orr, Jr.

    2001-12-31

    This report outlines progress in the first quarter of the second year of the DOE project ''High Resolution Prediction of Gas Injection Process Performance for Heterogeneous Reservoirs''. The application of the analytical theory for gas injection processes, including the effects of volume change on mixing, has up to now been limited to fully self-sharpening systems, systems where all solution segments that connect the key tie lines present in the displacement are shock fronts. In the following report, we describe the extension of the analytical theory to include systems with rarefactions (continuous composition and saturation variations) between key tie lines. With the completion of this analysis, a completely general procedure has been developed for finding solutions for problems in which a multicomponent gas displaces a multicomponent oil.

  18. Support vector regression for porosity prediction in a heterogeneous reservoir: A comparative study

    Science.gov (United States)

    Al-Anazi, A. F.; Gates, I. D.

    2010-12-01

    In wells with limited log and core data, porosity, a fundamental and essential property to characterize reservoirs, is challenging to estimate by conventional statistical methods from offset well log and core data in heterogeneous formations. Beyond simple regression, neural networks have been used to develop more accurate porosity correlations. Unfortunately, neural network-based correlations have limited generalization ability and global correlations for a field are usually less accurate compared to local correlations for a sub-region of the reservoir. In this paper, support vector machines are explored as an intelligent technique to correlate porosity to well log data. Recently, support vector regression (SVR), based on the statistical learning theory, have been proposed as a new intelligence technique for both prediction and classification tasks. The underlying formulation of support vector machines embodies the structural risk minimization (SRM) principle which has been shown to be superior to the traditional empirical risk minimization (ERM) principle employed by conventional neural networks and classical statistical methods. This new formulation uses margin-based loss functions to control model complexity independently of the dimensionality of the input space, and kernel functions to project the estimation problem to a higher dimensional space, which enables the solution of more complex nonlinear problem optimization methods to exist for a globally optimal solution. SRM minimizes an upper bound on the expected risk using a margin-based loss function ( ɛ-insensitivity loss function for regression) in contrast to ERM which minimizes the error on the training data. Unlike classical learning methods, SRM, indexed by margin-based loss function, can also control model complexity independent of dimensionality. The SRM inductive principle is designed for statistical estimation with finite data where the ERM inductive principle provides the optimal solution (the

  19. Implications of heterogeneous fracture distribution on reservoir quality; an analogue from the Torridon Group sandstone, Moine Thrust Belt, NW Scotland

    Science.gov (United States)

    Watkins, Hannah; Healy, David; Bond, Clare E.; Butler, Robert W. H.

    2018-03-01

    Understanding fracture network variation is fundamental in characterising fractured reservoirs. Simple relationships between fractures, stress and strain are commonly assumed in fold-thrust structures, inferring relatively homogeneous fracture patterns. In reality fractures are more complex, commonly appearing as heterogeneous networks at outcrop. We use the Achnashellach Culmination (NW Scotland) as an outcrop analogue to a folded tight sandstone reservoir in a thrust belt. We present fracture data is collected from four fold-thrust structures to determine how fracture connectivity, orientation, permeability anisotropy and fill vary at different structural positions. We use a 3D model of the field area, constructed using field observations and bedding data, and geomechanically restored using Move software, to determine how factors such as fold curvature and strain influence fracture variation. Fracture patterns in the Torridon Group are consistent and predictable in high strain forelimbs, however in low strain backlimbs fracture patterns are inconsistent. Heterogeneities in fracture connectivity and orientation in low strain regions do not correspond to fluctuations in strain or fold curvature. We infer that where strain is low, other factors such as lithology have a greater control on fracture formation. Despite unpredictable fracture attributes in low strain regions, fractured reservoir quality would be highest here because fractures in high strain forelimbs are infilled with quartz. Heterogeneities in fracture attribute data on fold backlimbs mean that fractured reservoir quality and reservoir potential is difficult to predict.

  20. Determination of heterogeneities in the hydraulic properties of a phreatic aquifer from tidal level fluctuations: a case in Argentina

    Science.gov (United States)

    Carol, Eleonora S.; Kruse, Eduardo E.; Pousa, Jorge L.; Roig, Alejandro R.

    2009-11-01

    A well-known analytical solution of Jacob (1950) for groundwater flow due to tidal-wave propagation, together with field measurements along a complete tidal cycle and geological data, were used to evaluate the heterogeneities in the hydraulic properties of a phreatic aquifer located next to the River Ajo in the coastal plain environment of the southern sector of the Samborombon Bay wetland, Argentina. From the analysis of water-table fluctuations in a set of monitoring wells located along a riverbank-normal transect, it was possible to quantify the piecewise spatial variations of the hydraulic diffusivity of the phreatic aquifer. The results show the strong lateral variations of the sedimentary environment due to the influence of the different transport and deposition agents that characterize the coastal plain. The known thickness of the phreatic aquifer and the estimated range of the specific yield allowed the hydraulic conductivity to be identified as the most influential factor. [Jacob CE (1950) Flow of ground water. In: Rouse H (ed) Engineering Hydraulics. Wiley, New York

  1. Structural control on the deep hydrogeological and geothermal aquifers related to the fractured Campanian-Miocene reservoirs of north-eastern Tunisia foreland constrained by subsurface data

    Science.gov (United States)

    Khomsi, Sami; Echihi, Oussema; Slimani, Naji

    2012-03-01

    A set of different data including high resolution seismic sections, petroleum wire-logging well data, borehole piezometry, structural cross-sections and outcrop analysis allowed us to characterise the tectonic framework, and its relationships with the deep aquifers seated in Cretaceous-Miocene deep reservoirs. The structural framework, based on major structures, controls the occurrence of deep aquifers and sub-basin aquifer distributions. Five structural domains can be defined, having different morphostructural characteristics. The northernmost domain lying on the north-south axis and Zaghouan thrust system is a domain of recharge by underflow of the different subsurface reservoirs and aquifers from outcrops of highly fractured reservoirs. On the other hand, the morphostructural configuration controls the piezometry of underground flows in the Plio-Quaternary unconfined aquifer. In the subsurface the Late Cretaceous-Miocene reservoirs are widespread with high thicknesses in many places and high porosities and connectivities especially along major fault corridors and on the crestal parts of major anticlines. Among all reservoirs, the Oligo-Miocene, detritic series are widespread and present high cumulative thicknesses. Subsurface and fieldwork outline the occurrence of 10 fractured sandy reservoirs for these series with packages having high hydrodynamic and petrophysical characteristics. These series show low salinities (maximum 5 g/l) in the northern part of the study area and will constitute an important source of drinkable water for the next generations. A regional structural cross-section is presented, compiled from all the different data sets, allowing us to define the major characteristics of the hydrogeological-hydrogeothermal sub-basins. Eight hydrogeological provinces are defined from north-west to south-east. A major thermal anomaly is clearly identified in the south-eastern part of the study area in Sfax-Sidi Il Itayem. This anomaly is possibly related to

  2. Characterization of aquifer heterogeneity in a complex fluvial hydrogeologic system to evaluate migration in ground water

    International Nuclear Information System (INIS)

    Baker, F.G.; Pavlik, H.F.

    1990-01-01

    The hydrogeology and extent of ground water contamination were characterized at a site in northern California. Wood preserving compounds, primarily pentachlorophenol (PCP) and creosote, have been detected in the soil and ground water. A plume of dissolved PCP up to 1.5 miles long has been identified south of the plant. The aquifer consists of a complex multizonal system of permeable gravels and sands composed of units from four geologic formations deposited by the ancestral Feather River. Fluvial channel gravels form the principal aquifer zones and contain overbank clay and silt deposits which locally form clay lenses or more continuous aquitards. The geometric mean horizontal hydraulic conductivities for channel gravels range between 120 to 530 feet/day. Mean vertical aquitard hydraulic conductivity is 0.07 feet/day. Ground water flow is generally southward with a velocity ranging from 470 to 1000 feet/year. The spatial distribution of dissolved PCP in the aquifer documents the interactions between major permeable zones. Hydrostratigraphic evidence pointing to the separation of aquifer zones is supported by the major ion chemistry of ground water. The sodium and calcium-magnesium bicarbonate-rich water present in the upper aquifer zones is significantly different in chemical composition from the predominantly sodium chloride-rich water present in the deeper permeable zone. This indicates that hydrodynamic separation exists between the upper and lower zones of the aquifer, limiting the vertical movement of the PCP plume. A numerical ground water model, based on this conceptual hydrogeologic model, was developed to evaluate groundwater transport pathways and for use in the design of a ground water extraction and treatment system. (9 refs., 7 figs., tab.)

  3. Sensitivity Studies on Productivity Performance from 3D Heterogeneous Reservoir Model Based on the L-Pad Gas Hydrate Accumulation in Prudhoe Bay Unit, North Slope Alaska

    Science.gov (United States)

    Myshakin, E. M.; Ajayi, T.; Seol, Y.; Boswell, R.

    2016-12-01

    Three-dimensional reservoir model of the "L-Pad" hydrate deposit located in the Prudhoe Bay region of the Alaska's North Slope was created including four stratigraphic units; silty shale overburden, hydrate-bearing D sand, inter-reservoir silty shale, hydrate-bearing C sand, and silty shale underburden. The model incorporates the actual geological settings, accounts for the presence of faults, reservoir dip, the hydrate-water contact in the C sand. Geostatistical porosity distributions in D and C sands conditioned to log data from 78 wells drilled in the vicinity of the Prudhoe Bay "L-pad" were developed providing vertical and lateral 3D heterogeneity in porosity and porosity-dependent hydrate saturation and intrinsic permeability. Gas production potential was estimated using a conventional vertical wellbore completion and a deviated toe-down wellbore perforated through both sand units to induce hydrate depressurization at a constant bottom-hole pressure. The results have shown the greater performance of the deviated well design over the vertical one. The scenarios involving simultaneous and sequential hydrate dissociation in sand units were explored and the effect of the underlying aquifer in the C sand was estimated. Sensitivity analysis has demonstrated that hydraulic communication with over- and underlying shale units affects production in the beginning of depressurization due to competitive water influx into producing mobile flow and could suppress efficient hydrate decomposition resulting in production lag. Another important factor greatly influencing the productivity performance is the effective permeability of hydrate-bearing sediment controlled by the relative permeability function. The results call for the necessity of thorough fundamental studies to understand multi-phase flow in hydrate-bearing sediments with different hydrate precipitation habits.

  4. Scale-up of miscible flood processes for heterogeneous reservoirs. Quarterly report, April 1--June 30, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Orr, F.M. Jr.

    1995-06-01

    The current project is a systematic research effort aimed at quantifying relationships between process mechanisms that can lead to improved recovery from gas injection processes performed in heterogeneous Class 1 and Class 2 reservoirs. It will provide a rational basis for the design of displacement processes that take advantage of crossflow due to capillary, gravity and viscous forces to offset partially the adverse effects of heterogeneity. In effect, the high permeability zones are used to deliver fluid by crossflow to zones that would otherwise be flooded only very slowly. Thus, the research effort is divided into five areas: Development of miscibility in multicomponent systems; Design estimates for nearly miscible displacements; Design of miscible floods for fractured reservoirs; Compositional flow visualization experiments; Simulation of near-miscible flow in heterogeneous systems The status of the research effort in each area is reviewed briefly in the following section.

  5. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Franklin M. Orr, Jr.

    2004-05-01

    This final technical report describes and summarizes results of a research effort to investigate physical mechanisms that control the performance of gas injection processes in heterogeneous reservoirs and to represent those physical effects in an efficient way in simulations of gas injection processes. The research effort included four main lines of research: (1) Efficient compositional streamline methods for 3D flow; (2) Analytical methods for one-dimensional displacements; (3) Physics of multiphase flow; and (4) Limitations of streamline methods. In the first area, results are reported that show how the streamline simulation approach can be applied to simulation of gas injection processes that include significant effects of transfer of components between phases. In the second area, the one-dimensional theory of multicomponent gas injection processes is extended to include the effects of volume change as components change phase. In addition an automatic algorithm for solving such problems is described. In the third area, results on an extensive experimental investigation of three-phase flow are reported. The experimental results demonstrate the impact on displacement performance of the low interfacial tensions between the gas and oil phases that can arise in multicontact miscible or near-miscible displacement processes. In the fourth area, the limitations of the streamline approach were explored. Results of an experimental investigation of the scaling of the interplay of viscous, capillary, and gravity forces are described. In addition results of a computational investigation of the limitations of the streamline approach are reported. The results presented in this report establish that it is possible to use the compositional streamline approach in many reservoir settings to predict performance of gas injection processes. When that approach can be used, it requires substantially less (often orders of magnitude) computation time than conventional finite difference

  6. Lead Isotope Compositions of Acid Residues from Olivine-Phyric Shergottite Tissint: Implications for Heterogeneous Shergottite Source Reservoirs

    Science.gov (United States)

    Moriwaki, R.; Usui, T.; Yokoyama, T.; Simon, J. I.; Jones, J. H.

    2015-01-01

    Geochemical studies of shergottites suggest that their parental magmas reflect mixtures between at least two distinct geochemical source reservoirs, producing correlations between radiogenic isotope compositions and trace element abundances. These correlations have been interpreted as indicating the presence of a reduced, incompatible element- depleted reservoir and an oxidized, incompatible- element-enriched reservoir. The former is clearly a depleted mantle source, but there is ongoing debate regarding the origin of the enriched reservoir. Two contrasting models have been proposed regarding the location and mixing process of the two geochemical source reservoirs: (1) assimilation of oxidized crust by mantle derived, reduced magmas, or (2) mixing of two distinct mantle reservoirs during melting. The former requires the ancient Martian crust to be the enriched source (crustal assimilation), whereas the latter requires isolation of a long-lived enriched mantle domain that probably originated from residual melts formed during solidification of a magma ocean (heterogeneous mantle model). This study conducts Pb isotope and trace element concentration analyses of sequential acid-leaching fractions (leachates and the final residues) from the geochemically depleted olivine-phyric shergottite Tissint. The results suggest that the Tissint magma is not isotopically uniform and sampled at least two geochemical source reservoirs, implying that either crustal assimilation or magma mixing would have played a role in the Tissint petrogenesis.

  7. Flooding of the Saar-Lorraine Coal Mines: coupling of the regional model of the lower triassic sandstones aquifer with a 'box' model of the mining reservoir

    International Nuclear Information System (INIS)

    Babot, Y.; Duzan, A.; Eckart, M.; Kories, H.; Metz, M.; Rengers, R.

    2005-01-01

    Charbonnages de France (CdF) and Deutsche Steinkohle AG (DSK) has mandated the ANTEA/DMT working group to draw up a trans-border groundwater / mining reservoir coupling model for the Center-East sector. This coupling makes it possible to calculate pumping flows, according to pressure losses between mines, in order to prevent brackish water intrusion from mines to the Lower Triassic Sandstones aquifer. (authors)

  8. Heterogeneous carbonaceous matter in sedimentary rock lithocomponents causes significant trichloroethylene (TCE) sorption in a low organic carbon content aquifer/aquitard system

    Science.gov (United States)

    Choung, Sungwook; Zimmerman, Lisa R.; Allen-King, Richelle M.; Ligouis, Bertrand; Feenstra, Stanley

    2014-10-01

    This study evaluated the effects of heterogeneous thermally altered carbonaceous matter (CM) on trichloroethylene (TCE) sorption for a low fraction organic carbon content (foc) alluvial sedimentary aquifer and aquitard system (foc = 0.046-0.105%). The equilibrium TCE sorption isotherms were highly nonlinear with Freundlich exponents of 0.46-0.58. Kerogen + black carbon was the dominant CM fraction extracted from the sediments and accounted for > 60% and 99% of the total in the sands and silt, respectively. Organic petrological examination determined that the kerogen included abundant amorphous organic matter (bituminite), likely of marine origin. The dark calcareous siltstone exhibited the greatest TCE sorption among aquifer lithocomponents and accounted for most sorption in the aquifer. The results suggest that the source of the thermally altered CM, which causes nonlinear sorption, was derived from parent Paleozoic marine carbonate rocks that outcrop throughout much of New York State. A synthetic aquifer-aquitard unit system (10% aquitard) was used to illustrate the effect of the observed nonlinear sorption on mass storage potential at equilibrium. The calculation showed that > 80% of TCE mass contained in the aquifer was sorbed on the aquifer sediment at aqueous concentration < 1000 μg L- 1. These results show that sorption is likely a significant contributor to the persistence of a TCE groundwater plume in the aquifer studied. It is implied that sorption may similarly contribute to TCE persistence in other glacial alluvial aquifers with similar geologic characteristics, i.e., comprised of sedimentary rock lithocomponents that contain thermally altered CM.

  9. Predicting interwell heterogeneity in fluvial-deltaic reservoirs: Outcrop observations and applications of progressive facies variation through a depositional cycle

    Energy Technology Data Exchange (ETDEWEB)

    Knox, P.R.; Barton, M.D. [Univ. of Texas, Austin, TX (United States)

    1997-08-01

    Nearly 11 billion barrels of mobile oil remain in known domestic fluvial-deltaic reservoirs despite their mature status. A large percentage of this strategic resource is in danger of permanent loss through premature abandonment. Detailed reservoir characterization studies that integrate advanced technologies in geology, geophysics, and engineering are needed to identify remaining resources that can be targeted by near-term recovery methods, resulting in increased production and the postponement of abandonment. The first and most critical step of advanced characterization studies is the identification of reservoir architecture. However, existing subsurface information, primarily well logs, provides insufficient lateral resolution to identify low-permeability boundaries that exist between wells and compartmentalize the reservoir. Methods to predict lateral variability in fluvial-deltaic reservoirs have been developed on the basis of outcrop studies and incorporate identification of depositional setting and position within a depositional cycle. The position of a reservoir within the framework of a depositional cycle is critical. Outcrop studies of the Cretaceous Ferron Sandstone of Utah have demonstrated that the architecture and internal heterogeneity of sandstones deposited within a given depositional setting (for example, delta front) vary greatly depending upon whether they were deposited in the early, progradational part of a cycle or the late, retrogradational part of a cycle. The application of techniques similar to those used by this study in other fluvial-deltaic reservoirs will help to estimate the amount and style of remaining potential in mature reservoirs through a quicklook evaluation, allowing operators to focus characterization efforts on reservoirs that have the greatest potential to yield additional resources.

  10. MRF-based Stochastic Joint Inversion of Hydrological and Geophysical Datasets to Evaluate Aquifer Heterogeneities.

    Science.gov (United States)

    Oware, E. K.

    2016-12-01

    Hydrogeophysical assessment of aquifer parameters typically involve sparse noisy measurements coupled with incomplete understanding of the underlying physical process. Thus, recovering a single deterministic solution in light of the largely uncertain inputs is unrealistic. Stochastic imaging (SI) allows the retrieval of multiple equiprobable outcomes that facilitate probabilistic assessment of aquifer properties in a realistic fashion. Representation of prior models is a key aspect of the formulation of SI frameworks. However, higher-order (HO) statistics for representing complex priors in SI are usually borrowed from training images (TIs), which may bias outcomes if the prior hypotheses are inaccurate. A data-driven HO simulation alternative based on Markov random field (MRF) modeling is presented. Here, the modeling of spatial features is guided by potential (Gibbs) energy (PE) minimization. The estimation of the PE encompasses local neighborhood configuration (LNC) and prior statistical constraints. The lower the estimated PE the higher the likelihood of that particular local structure and vice versa. Hence, the LNC component of the PE estimation is designed to promote the recovery of some desired structures while penalizing the retrieval of patterns that are inconsistent with prior expectation. The statistical structure is adaptively inferred from the joint conditional datasets. The reconstruction proceeds in two-steps with the estimation of the lithological structure of the aquifer followed by the simulation of attributes within the identified lithologies. This two-step approach permits the delineation of physically realistic crisp lithological boundaries. The algorithm is demonstrated with a joint inversion of time-lapse concentration and electrical resistivity measurements, in a hypothetical trinary hydrofacies aquifer characterization problem.

  11. High-resolution characterization of chemical heterogeneity in an alluvial aquifer

    Science.gov (United States)

    Schulmeister, M.K.; Healey, J.M.; Butler, J.J.; McCall, G.W.; Birk, S.

    2002-01-01

    The high-resolution capabilities of direct push technology were exploited to develop new insights into the hydrochemistry at the margin of an alluvial aquifer. Hydrostratigraphic controls on groundwater flow and contaminant loading were revealed through the combined use of direct push electrical conductivity (EC) logging and geochemical profiling. Vertical and lateral variations in groundwater chemistry were consistent with sedimentary features indicated by EC logs, and were supported by a conceptual model of recharge along the flood plain margin.

  12. An approximate analytical methodology for the concentration CDF and corresponding adverse health effects in 3D heterogeneous aquifers

    Science.gov (United States)

    Zarlenga, Antonio; de Barros, Felipe; Fiori, Aldo

    2017-04-01

    Predicting solutes displacement in ecosystems is a complex task because of heterogeneity of hydrogeological properties and limited financial resources for characterization. As a consequence, solute transport model predictions are subject to uncertainty and probabilistic methods are invoked. Despite the significant theoretical advances in subsurface hydrology, there is a compelling need to transfer those specialized know-hows into an easy-to-use practical tool. The deterministic approach is able to capture some features of the transport behavior but its adoption in practical applications (e.g. remediation strategies or health risk assessment) is often inadequate because of its inability to accurately model the phenomena triggered by the spatial heterogeneity. The rigorous evaluation of the local contaminant concentration in natural aquifers requires an accurate estimate of the domain properties and huge computational times; those aspects limit the adoption of fully 3D numerical models. In this presentation, we illustrate a physically-based methodology to analytically estimate of the statistics of the solute concentration in natural aquifers and the related health risk. Our methodology aims to provide a simple tool for a quick assessment of the contamination level in aquifers, as function of a few relevant, physically based parameters such as the log conductivity variance, the mean flow velocity, the Péclet number. Solutions of the 3D analytical model adopt the results of previous works: transport model is based on the solutions proposed by Zarlenga and Fiori (2013, 2014) where semi-analytical relations for the statics of local contaminant concentration are carry out through a Lagrangian first-order model. As suggested in de Barros and Fiori (2014), the Beta distribution is assumed for the concentration cumulative density function (CDF). We illustrate the use of the closed-form equations for the probability of local contaminant concentration and health risk in a

  13. Conformance Control in Heterogeneous Oil Reservoirs with Polymer Gels and Nano-Spheres

    NARCIS (Netherlands)

    Lenchenkov, N.

    2017-01-01

    In many oil fields, water is injected into a reservoir to displace oil to the production wells. During the injection process, oil is pushed by water towards production wells which have a lower pressure than the rest of the reservoir. If the reservoir is homogeneous, then a good sweep efficiency of

  14. Element mobilization and immobilization from carbonate rocks between CO 2 storage reservoirs and the overlying aquifers during a potential CO 2 leakage

    Energy Technology Data Exchange (ETDEWEB)

    Lawter, Amanda R.; Qafoku, Nikolla P.; Asmussen, R. Matthew; Kukkadapu, Ravi K.; Qafoku, Odeta; Bacon, Diana H.; Brown, Christopher F.

    2018-04-01

    Despite the numerous studies on changes within the reservoir following CO2 injection and the effects of CO2 release into overlying aquifers, little or no literature is available on the effect of CO2 release on rock between the storage reservoirs and subsurface. To address this knowledge gap, relevant rock materials, temperatures and pressures were used to study mineralogical and elemental changes in this intermediate zone. After rocks reacted with CO2, liquid analysis showed an increase of major elements (e.g., Ca, and Mg) and variable concentrations of potential contaminants (e.g., Sr and Ba); lower concentrations were observed in N2 controls. In experiments with As/Cd and/or organic spikes, representing potential contaminants in the CO2 plume originating in the storage reservoir, most or all of these contaminants were removed from the aqueous phase. SEM and Mössbauer spectroscopy results showed the formation of new minerals and Fe oxides in some CO2-reacted samples, indicating potential for contaminant removal through mineral incorporation or adsorption onto Fe oxides. These experiments show the interactions between the CO2-laden plume and the rock between storage reservoirs and overlying aquifers have the potential to affect the level of risk to overlying groundwater, and should be considered during site selection and risk evaluation.

  15. An Integrated Rock Typing Approach for Unraveling the Reservoir Heterogeneity of Tight Sands in the Whicher Range Field of Perth Basin, Western Australia

    DEFF Research Database (Denmark)

    Ilkhchi, Rahim Kadkhodaie; Rezaee, Reza; Harami, Reza Moussavi

    2014-01-01

    between pore system properties and depositional and diagenetic characteristics in each sand type, reservoir rock types were extracted. The identified reservoir rock types are in fact a reflection of internal reservoir heterogeneity related to pore system properties. All reservoir rock types...... are characterized by a compacted fabric and cemented framework. But distribution and dominance of diagenetic products in each of them depend on primary depositional composition and texture. The results show that reservoir rock typing based on three aspects of reservoir sandstones (depositional properties......Tight gas sands in Whicher Range Field of Perth Basin show large heterogeneity in reservoir characteristics and production behavior related to depositional and diagenetic features. Diagenetic events (compaction and cementation) have severely affected the pore system. In order to investigate...

  16. Simulation of geothermal water extraction in heterogeneous reservoirs using dynamic unstructured mesh optimisation

    Science.gov (United States)

    Salinas, P.; Pavlidis, D.; Jacquemyn, C.; Lei, Q.; Xie, Z.; Pain, C.; Jackson, M.

    2017-12-01

    It is well known that the pressure gradient into a production well increases with decreasing distance to the well. To properly capture the local pressure drawdown into the well a high grid or mesh resolution is required; moreover, the location of the well must be captured accurately. In conventional simulation models, the user must interact with the model to modify grid resolution around wells of interest, and the well location is approximated on a grid defined early in the modelling process.We report a new approach for improved simulation of near wellbore flow in reservoir scale models through the use of dynamic mesh optimisation and the recently presented double control volume finite element method. Time is discretized using an adaptive, implicit approach. Heterogeneous geologic features are represented as volumes bounded by surfaces. Within these volumes, termed geologic domains, the material properties are constant. Up-, cross- or down-scaling of material properties during dynamic mesh optimization is not required, as the properties are uniform within each geologic domain. A given model typically contains numerous such geologic domains. Wells are implicitly coupled with the domain, and the fluid flows is modelled inside the wells. The method is novel for two reasons. First, a fully unstructured tetrahedral mesh is used to discretize space, and the spatial location of the well is specified via a line vector, ensuring its location even if the mesh is modified during the simulation. The well location is therefore accurately captured, the approach allows complex well trajectories and wells with many laterals to be modelled. Second, computational efficiency is increased by use of dynamic mesh optimization, in which an unstructured mesh adapts in space and time to key solution fields (preserving the geometry of the geologic domains), such as pressure, velocity or temperature, this also increases the quality of the solutions by placing higher resolution where required

  17. Experiments and Simulations of Fluid Flow in Heterogeneous Reservoir Models - Emphasis on Impacts from Crossbeds and Fractures

    Energy Technology Data Exchange (ETDEWEB)

    Boerresen, Knut Arne

    1996-12-31

    Hydrocarbon recovery from subsurface reservoirs has become increasingly dependent on advanced recovery techniques that require improved understanding of the physics of fluid flow within and across geological units including small-scale heterogeneities and fractures. In this thesis, impacts from heterogeneities on local fluid flow are studied experimentally by means of imaging techniques to visualize fluid flow in two dimensions during flooding of larger reservoir models. Part 1 reflects the multi-disciplinary collaboration, by briefly introducing the relevant geology, the literature on experiments on fluid flow in bedded structures, and outlining the applied numerical simulator and imaging techniques applied to visualize fluid flow. The second part contains a synopsis of displacement experiments in naturally laminated sandstones and in crossbed laboratory models, and of the impact from incipient shear fractures on oil recovery. The detailed results obtained from the experiments and simulations are described in six papers, all included. 215 refs., 108 figs., 16 tabs.

  18. Assessing submarine groundwater discharge (SGD) and nitrate fluxes in highly heterogeneous coastal karst aquifers: Challenges and solutions

    Science.gov (United States)

    Montiel, Daniel; Dimova, Natasha; Andreo, Bartolomé; Prieto, Jorge; García-Orellana, Jordi; Rodellas, Valentí

    2018-02-01

    Groundwater discharge in coastal karst aquifers worldwide represents a substantial part of the water budget and is a main pathway for nutrient transport to the sea. Groundwater discharge to the sea manifests under different forms, making its assessment very challenging particularly in highly heterogeneous coastal systems karst systems. In this study, we present a methodology approach to identify and quantify four forms of groundwater discharge in a mixed lithology system in southern Spain (Maro-Cerro Gordo) that includes an ecologically protected coastal area comprised of karstic marble. We found that groundwater discharge to the sea occurs via: (1) groundwater-fed creeks, (2) coastal springs, (3) diffuse groundwater seepage through seabed sediments, and (4) submarine springs. We used a multi-method approach combining tracer techniques (salinity, 224Ra, and 222Rn) and direct measurements (seepage meters and flowmeters) to evaluate the discharge. Groundwater discharge via submarine springs was the most difficult to assess due to their depth (up to 15 m) and extensive development of the springs conduits. We determined that the total groundwater discharge over the 16 km of shoreline of the study area was at least 11 ± 3 × 103 m3 d-1 for the four types of discharge assessed. Groundwater-derived nitrate (NO3-) fluxes to coastal waters over ∼3 km (or 20%) in a highly populated and farmed section of Maro-Cerro Gordo was 641 ± 166 mol d-1, or ∼75% of the total NO3- loading in the study area. We demonstrate in this study that a multi-method approach must be applied to assess all forms of SGD and derived nutrient fluxes to the sea in highly heterogeneous karst aquifer systems.

  19. Improved Characterization of Groundwater Flow in Heterogeneous Aquifers Using Granular Polyacrylamide (PAM) Gel as Temporary Grout

    Science.gov (United States)

    Klepikova, Maria V.; Roques, Clement; Loew, Simon; Selker, John

    2018-02-01

    The range of options for investigation of hydraulic behavior of aquifers from boreholes has been limited to rigid, cumbersome packers, and inflatable sleeves. Here we show how a new temporary borehole sealing technique using soft grains of polyacrylamide (PAM) gel as a sealing material can be used to investigate natural groundwater flow dynamics and discuss other possible applications of the technology. If no compressive stress is applied, the gel packing, with a permeability similar to open gravel, suppresses free convection, allowing for local temperature measurements and chemical sampling through free-flowing gel packing. Active heating laboratory and field experiments combined with temperature measurements along fiber optic cables were conducted in water-filled boreholes and boreholes filled with soft grains of polyacrylamide gel. The gel packing is shown to minimize the effect of free convection within the well column and enable detection of thin zones of relatively high or low velocity in a highly transmissive alluvial aquifer, thus providing a significant improvement compared to temperature measurements in open boreholes. Laboratory experiments demonstrate that under modest compressive stress to the gel media the permeability transitions from highly permeable to nearly impermeable grouting. Under this configuration the gel packing could potentially allow for monitoring local response pressure from the formation with all other locations in the borehole hydraulically isolated.

  20. Synergy of climate change and local pressures on saltwater intrusion in heterogeneous coastal aquifers

    Science.gov (United States)

    Abou Najm, M.; Safi, A.; El-Fadel, M.; Doummar, J.; Alameddine, I.

    2016-12-01

    The relative importance of climate change induced sea level rise on the salinization of a highly urbanized karstified coastal aquifers were compared with non-sustainable pumping. A 3D variable-density groundwater flow and solute transport model was used to predict the displacement of the saltwater-freshwater interface in a pilot aquifer located along the Eastern Mediterranean. The results showed that the influence of sea level rise was marginal when compared with the encroachment of salinity associated with anthropogenic abstraction. Model predictions of salinity mass and volumetric displacement of the interface corresponding to a long-term monthly transient model showed that the saltwater intrusion dynamic is highly sensitive to change in the abstraction rates which were estimated based on combinations of water consumption rates and population growth rates. Salinity encroachment, however, appeared to be more sensitive to water consumption rates in comparison to population growth rates, where a 50% increase in the rate of former led to four times more intrusion as compared to an equivalent increase in population growth rate over 20 years. Coupling both increase in population growth and increased consumption rates had a synergistic effect that aggravated the intrusion beyond the sum of the individual impacts. Adaptation strategies targeting a decrease in groundwater exploitation proved to be effective in retarding the intrusion.

  1. Anionic co-contaminants and the biogeochemical evolution of aquifer heterogeneity. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Fish, W.

    1997-07-01

    Adsorption heterogeneity of subsoils may depend on the sorbate and its concentration. Ligands in natural and contaminated subsoils may dissolve substantial metal oxides thereby altering the subsoil heterogeneity. We investigated these hypotheses on sands artificially and naturally coated with various amounts of metal oxides. The adsorbates Cu, oxalate, and mixtures of Cu and oxalate (Cu-Oxalate) were used as probes of the surface. For the concentration range studied, Binding Strength Analysis revealed that the naturally coated samples were heterogeneous at the microscale and the macroscale when oxalate was used as the probe of the surface. Cu revealed a smaller heterogeneity while Cu-Oxalate indicated an intermediate heterogeneity. Various elaborations of homogeneous-site Surface Complexation Models (SCM), calibrated to the surface protonation properties of goethite, modeled accurately the edges of oxalate, Cu, and mixtures of Cu and oxalate. The poorer fits for large concentrations was probably because of the site heterogeneity. The accuracy of SCMs was insensitive to the choice of surface protonation constants (pK{sub a}) and moderately sensitive to the choice of site density. The effective surface complexation constants (K{sup eff}) obtained from individual edges were somewhat different because of the concentration dependent heterogeneity. It was not always possible to use K{sup eff} values for one sorbate concentration to reproduce adsorption of other concentrations of the same sorbate. A modified version of the discrete pK{sub a} spectrum model closely reproduced the acid-base titration curve with two adsorption sites (four pK{sub a}`s). The adsorption of all concentrations of Cu, oxalate, and Cu-Oxalate was often reproduced with only one of those sites. The competition between the dissolved Al and the surface for the oxalate in solution was accurately reproduced with both sites. The dissolution of the oxide coating was often influenced by the pore velocity.

  2. Element mobilization and immobilization from carbonate rocks between CO2storage reservoirs and the overlying aquifers during a potential CO2leakage.

    Science.gov (United States)

    Lawter, Amanda R; Qafoku, Nikolla P; Asmussen, R Matthew; Kukkadapu, Ravi K; Qafoku, Odeta; Bacon, Diana H; Brown, Christopher F

    2018-04-01

    Despite the numerous studies on changes within the reservoir following CO 2 injection and the effects of CO 2 release into overlying aquifers, little or no literature is available on the effect of CO 2 release on rock between the storage reservoirs and subsurface. This is important, because the interactions that occur in this zone between the CO 2 storage reservoir and the subsurface may have a significant impact on risk analysis for CO 2 storage projects. To address this knowledge gap, relevant rock materials, temperatures and pressures were used to study mineralogical and elemental changes in this intermediate zone. After rocks reacted with CO 2 -acidified 0.01 M NaCl, liquid analysis showed an increase of major elements (e.g., Ca and Mg) and variable concentrations of potential contaminants (e.g., Sr and Ba); lower aqueous concentrations of these elements were observed in N 2 control experiments, likely due to differences in pH between the CO 2 and N 2 experiments. In experiments with As/Cd and/or organic spikes, representing potential contaminants in the CO 2 plume originating in the storage reservoir, most or all of these contaminants were removed from the aqueous phase. SEM and Mössbauer spectroscopy results showed the formation of new minerals and Fe oxides in some CO 2 -reacted samples, indicating potential for contaminant removal through mineral incorporation or adsorption onto Fe oxides. These experiments show the interactions between the CO 2 -laden plume and the rock between storage reservoirs and overlying aquifers have the potential to affect the level of risk to overlying groundwater, and should be considered during site selection and risk evaluation. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Spatio-temporal variation in groundwater head affected by stratigraphic heterogeneity of the alluvial aquifer in Northwest India

    Science.gov (United States)

    van Dijk, W. M.; Joshi, S. K.; Densmore, A. L.; Jackson, C. R.; Sutanudjaja, E.; Lafare, A. E. A.; Gupta, S.; Mackay, J. D.; Mason, P. J.; Sinha, R.

    2017-12-01

    Groundwater is a primary source of freshwater in the alluvial aquifer system of northwestern India. Unsustainable exploitation of the groundwater resources has led to a regional hotspot in groundwater depletion. Rapid groundwater-level decline shows spatial variation, as the effects of various stresses, including precipitation, potential evapotranspiration and abstraction, are likely to be influenced by the stratigraphic and geomorphic heterogeneity between sediment fan and interfan areas (see Geomorphological map in Figure A). We used a transfer function-noise (TFN) time series approach to quantify the effect of the various stress components in the period 1974-2010, based on predefined impulse response functions (IRFs) of von Asmuth et al. (2008). The objective of this study was 1) to acquire the impulse response function of various stresses, 2) assess the spatial estimation parameter (the zeroth moment, M0) of the spatial development of the groundwater head and 3) relate the spatial M0 to the observed stratigraphic and geomorphic heterogeneity. We collected information on the groundwater head pre- and post-monsoon, the district-wise monthly precipitation and potential evapotranspiration, and we modeled the monthly abstraction rate using land-use information. The TFN identified the IRF of precipitation as well as abstraction. The IRF, summarized in the parameter M0, identified a hotspot for the abstraction stress (see M0 spatial map for abstraction in Figure B) at the margins of the Sutlej and Yamuna fans. No hotspot is observed for the precipitation stress, but the M0 for precipitation increases with distance from the Himalayan front. At larger distances from the Himalayan front, observed groundwater head rises cannot be explained by the IRFs for the abstraction and precipitation stresses. This is likely because the current TFN models do not account for other stresses, such as recharge by canal leakage, which are locally important. We conclude that the spatial

  4. Quantification of oil recovery efficiency, CO 2 storage potential, and fluid-rock interactions by CWI in heterogeneous sandstone oil reservoirs

    DEFF Research Database (Denmark)

    Seyyedi, Mojtaba; Sohrabi, Mehran; Sisson, Adam

    2017-01-01

    Significant interest exists in improving recovery from oil reservoirs while addressing concerns about increasing CO2 concentrations in the atmosphere. The combination of Enhanced Oil Recovery (EOR) and safe geologic storage of CO2 in oil reservoirs is appealing and can be achieved by carbonated (...... for oil recovery and CO2 storage potential on heterogeneous cores. Since not all the oil reservoirs are homogenous, understanding the potential of CWI as an integrated EOR and CO2 storage scenario in heterogeneous oil reservoirs is essential.......Significant interest exists in improving recovery from oil reservoirs while addressing concerns about increasing CO2 concentrations in the atmosphere. The combination of Enhanced Oil Recovery (EOR) and safe geologic storage of CO2 in oil reservoirs is appealing and can be achieved by carbonated (CO...

  5. An Integrated Rock Typing Approach for Unraveling the Reservoir Heterogeneity of Tight Sands in the Whicher Range Field of Perth Basin, Western Australia

    DEFF Research Database (Denmark)

    Ilkhchi, Rahim Kadkhodaie; Rezaee, Reza; Harami, Reza Moussavi

    2014-01-01

    Tight gas sands in Whicher Range Field of Perth Basin show large heterogeneity in reservoir characteristics and production behavior related to depositional and diagenetic features. Diagenetic events (compaction and cementation) have severely affected the pore system. In order to investigate...... the petrophysical characteristics, reservoir sandstone facies were correlated with core porosity and permeability and their equivalent well log responses to describe hydraulic flow units and electrofacies, respectively. Thus, very tight, tight, and sub-tight sands were differentiated. To reveal the relationship......, diagenetic features and petrophysical characteristics) is a suitable technique for depiction of reservoir heterogeneity, recognition of reservoir units and identifying factors controlling reservoir quality of tight sandstones. This methodology can be used for the other tight reservoirs....

  6. Interdisciplinary study of reservoir compartments and heterogeneity. Final report, October 1, 1993--December 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Van Kirk, C.

    1998-01-01

    A case study approach using Terry Sandstone production from the Hambert-Aristocrat Field, Weld County, Colorado was used to document the process of integration. One specific project goal is to demonstrate how a multidisciplinary approach can be used to detect reservoir compartmentalization and improve reserve estimates. The final project goal is to derive a general strategy for integration for independent operators. Teamwork is the norm for the petroleum industry where teams of geologists, geophysicists, and petroleum engineers work together to improve profits through a better understanding of reservoir size, compartmentalization, and orientation as well as reservoir flow characteristics. In this manner, integration of data narrows the uncertainty in reserve estimates and enhances reservoir management decisions. The process of integration has proven to be iterative. Integration has helped identify reservoir compartmentalization and reduce the uncertainty in the reserve estimates. This research report documents specific examples of integration and the economic benefits of integration.

  7. The impact of local diffusion on longitudinal macrodispersivity and its major effect upon anomalous transport in highly heterogeneous aquifers

    Science.gov (United States)

    Janković, Igor; Fiori, Aldo; Dagan, Gedeon

    2009-05-01

    Flow and transport are solved for a heterogeneous medium modeled as an ensemble of spherical inclusions of uniform radius R and of conductivities K, drawn from a pdf f(K) ( Fig. 1). This can be regarded as a particular discretization scheme, allowing for accurate numerical and semi-analytical solutions, for any given univariate f(Y)(Y=lnK) and integral scale IY. The transport is quantified by the longitudinal equivalent macrodispersivity α, for uniform mean flow of velocity U and for a large (ergodic) plume of a conservative solute injected in a vertical plane ( x=0) and moving past a control plane at x≫IY. In the past we have solved transport for advection solely for highly heterogeneous media of σY2⩽8. We have found that α increases in a strong nonlinear fashion with σY2 and transport becomes anomalous for the subordinate model. This effect is explained by the large residence time of solute particles in inclusions of low K. In the present work we examine the impact of local diffusion as quantified by the Peclet number Pe=UIY/D0, where D0 is the coefficient of molecular diffusion. Transport with diffusion is solved by accurate numerical simulations for flow past spheres of low K and for high Pe=O(102-104). It was found that finite Pe reduces significantly α as compared to advection, for σY2≳3(Pe=1000) and for σY2≳1.4(Pe=100), justifying neglection of the effect of diffusion for weak to moderately heterogeneous aquifers (e.g. σY2⩽1). In contrast, diffusion impacts considerably α for large σY2 due to the removal of solute from low K inclusions. Furthermore, anomalous behavior is eliminated, though α may be still large for Pe≫1.

  8. Integrating non-colocated well and geophysical data to capture subsurface heterogeneity at an aquifer recharge and recovery site

    Science.gov (United States)

    Gottschalk, Ian P.; Hermans, Thomas; Knight, Rosemary; Caers, Jef; Cameron, David A.; Regnery, Julia; McCray, John E.

    2017-12-01

    Geophysical data have proven to be very useful for lithological characterization. However, quantitatively integrating the information gained from acquiring geophysical data generally requires colocated lithological and geophysical data for constructing a rock-physics relationship. In this contribution, the issue of integrating noncolocated geophysical and lithological data is addressed, and the results are applied to simulate groundwater flow in a heterogeneous aquifer in the Prairie Waters Project North Campus aquifer recharge site, Colorado. Two methods of constructing a rock-physics transform between electrical resistivity tomography (ERT) data and lithology measurements are assessed. In the first approach, a maximum likelihood estimation (MLE) is used to fit a bimodal lognormal distribution to horizontal crosssections of the ERT resistivity histogram. In the second approach, a spatial bootstrap is applied to approximate the rock-physics relationship. The rock-physics transforms provide soft data for multiple point statistics (MPS) simulations. Subsurface models are used to run groundwater flow and tracer test simulations. Each model's uncalibrated, predicted breakthrough time is evaluated based on its agreement with measured subsurface travel time values from infiltration basins to selected groundwater recovery wells. We find that incorporating geophysical information into uncalibrated flow models reduces the difference with observed values, as compared to flow models without geophysical information incorporated. The integration of geophysical data also narrows the variance of predicted tracer breakthrough times substantially. Accuracy is highest and variance is lowest in breakthrough predictions generated by the MLE-based rock-physics transform. Calibrating the ensemble of geophysically constrained models would help produce a suite of realistic flow models for predictive purposes at the site. We find that the success of breakthrough predictions is highly

  9. What is geological entropy and why measure it? A parsimonious approach for predicting transport behaviour in heterogeneous aquifers

    Science.gov (United States)

    Bianchi, Marco; Pedretti, Daniele

    2017-04-01

    We present an approach to predict non-Fickian transport behaviour in alluvial aquifers from knowledge of physical heterogeneity. This parsimonious approach is based on only two measurable parameters describing the global variability and the structure of the hydraulic conductivity (K) field: the variance of the ln(K) values (σY 2), and a newly developed index of geological entropy (HR), based on the concept of Shannon information entropy. Both σY 2 and HR can be obtained from data collected during conventional hydrogeological investigations and from the analysis of a representative model of the spatial distribution of K classes (e.g. hydrofacies) over the domain of interest. The new index HR integrates multiple characteristics of the K field, including the presence of well-connected features, into a unique metric that quantifies the degrees of spatial disorder in the K field structure. Stochastic simulations of tracer tests in synthetic K fields based on realistic distributions of hydrofacies in alluvial aquifers are conducted to identify empirical relations between HR, σY 2, and the first three central temporal moments of the resulting breakthrough curves (BTCs). Results indicate that the first and second moments tend to increase with spatial disorder (i.e, HR increasing). Conversely, high values of the third moment (i.e. skewness), which indicate significant post-peak tailing in the BTCs and non-Fickian transport behaviour, are observed in more orderly structures (i.e, HR decreasing), or for very high σY 2 values. We show that simple closed-form empirical expressions can be derived to describe the bivariate dependency between the skewness of the BTC and corresponding pairs of HR and σY 2. This dependency shows clear correlation for a broad range of structures and Kvariability levels. Therefore, it provides an effective and broadly applicable approach to explain and predict non-Fickian transport in real aquifers, such as those at the well-known MADE site and

  10. Reactive transport in the complex heterogeneous alluvial aquifer of Fortymile Wash, Nevada.

    Science.gov (United States)

    Soltanian, Mohamad Reza; Sun, Alexander; Dai, Zhenxue

    2017-07-01

    Yucca Mountain, Nevada, had been extensively investigated as a potential deep geologic repository for storing high-level nuclear wastes. Previous field investigations of stratified alluvial aquifer downstream of the site revealed that there is a hierarchy of sedimentary facies types. There is a corresponding log conductivity and reactive surface area subpopulations within each facies at each scale of sedimentary architecture. Here we use a Lagrangian-based transport model in order to analyze radionuclide dispersion in the saturated alluvium of Fortymile Wash, Nevada. First, we validate the Lagrangian model using high-resolution flow and reactive transport simulations. Then, we used the validated model to investigate how each scale of sedimentary architecture may affect long-term radionuclide transport at Yucca Mountain. Results show that the reactive solute dispersion developed by the Lagrangian model matches the ensemble average of numerical simulations well. The link between the alluvium spatial variability and reactive solute dispersion at different spatiotemporal scales is demonstrated using the Lagrangian model. The longitudinal dispersivity of the reactive plume can be on the order of hundreds to thousands of meters, and it may not reach its asymptotic value even after 10,000 years of travel time and 2-3 km of travel distance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. A field assessment of the value of steady shape hydraulic tomography for characterization of aquifer heterogeneities

    Science.gov (United States)

    Bohling, Geoffrey C.; Butler, James J.; Zhan, Xiaoyong; Knoll, Michael D.

    2007-01-01

    Hydraulic tomography is a promising approach for obtaining information on variations in hydraulic conductivity on the scale of relevance for contaminant transport investigations. This approach involves performing a series of pumping tests in a format similar to tomography. We present a field‐scale assessment of hydraulic tomography in a porous aquifer, with an emphasis on the steady shape analysis methodology. The hydraulic conductivity (K) estimates from steady shape and transient analyses of the tomographic data compare well with those from a tracer test and direct‐push permeameter tests, providing a field validation of the method. Zonations based on equal‐thickness layers and cross‐hole radar surveys are used to regularize the inverse problem. The results indicate that the radar surveys provide some useful information regarding the geometry of the K field. The steady shape analysis provides results similar to the transient analysis at a fraction of the computational burden. This study clearly demonstrates the advantages of hydraulic tomography over conventional pumping tests, which provide only large‐scale averages, and small‐scale hydraulic tests (e.g., slug tests), which cannot assess strata connectivity and may fail to sample the most important pathways or barriers to flow.

  12. Integration of Sedimentology,Petrophysics and Statistics for Characterizing the Reservoir Heterogeneity of the Late Ordovician Sarah Formation, Central Saudi Arabia

    Science.gov (United States)

    El-Deek, Islam; Abdullatif, Osman; Korvin, Gabor; Al-Ramadan, Khalid

    2014-05-01

    The first glaciogenic event in the Arabian Peninsula is represented by the Late Ordovician Sarah Formation. Sarah Formation is outcropping in areas of central and northern Arabia bordering the Arabian Shield, while it occupies several sub-basinal areas in the subsurface. The glacio-fluvial Sarah Formation is considered as an important tight gas reservoir target. This study uses the outcrop analog of the Sarah Formation to characterize the reservoir heterogeneity of the paleovalleys based on sedimentological, petrophysical, and statistical approaches. Facies types and architectural elements were identified within several paleovalleys of the Sarah Formation. The study indicated variability in texture, composition, sandstone type, facies, geometry and architecture at outcrop scale. Outcrop relationships also showed vertical and lateral facies change with other Paleozoic formations. The integration of field and laboratory data helped identifying the heterogeneity within Sarah paleovalleys. The reservoir quality trends in the Sarah Formation show variations that might be due to the controls of facies, depositional environments, and paleogeography. Three measures of heterogeneity were applied on the petrophysical data for various paleovalleys of the Sarah Formation. Those measures are: the coefficient of variation, Dykstra-Parsons, and Lorenz coefficients.The coefficient of variation values indicate extremely heterogeneous distribution. Dykstra-Parsons coefficient values suggest very to extremely heterogeneous reservoirs. Lorenz coefficients show good correlation with Dykstra-Parsons coefficient for Sarah paleovalleys. The studied heterogeneity measures indicate that Sarah paleovalleys represent very to extremely heterogeneous reservoirs.

  13. Colloid transport in a geochemically heterogeneous porous medium: aquifer tank experiment and modeling.

    Science.gov (United States)

    Loveland, Jonathan P; Bhattacharjee, Subir; Ryan, Joseph N; Elimelech, Menachem

    2003-09-01

    To examine colloid transport in geochemically heterogeneous porous media at a scale comparable to field experiments, we monitored the migration of silica-coated zirconia colloids in a two-dimensional layered porous media containing sand coated to three different extents by ferric oxyhydroxides. Transport of the colloids was measured over 1.65 m and 95 days. Colloid transport was modeled by an advection-dispersion-deposition equation incorporating geochemical heterogeneity and colloid deposition dynamics (blocking). Geochemical heterogeneity was represented as favorable (ferric oxyhydroxide-coated) and unfavorable (uncoated sand) deposition surface areas. Blocking was modeled as random sequential adsorption (RSA). Release of deposited colloids was negligible. The time to colloid breakthrough after the onset of blocking increased with increasing ferric oxyhydroxide-coated surface area. As the ferric oxyhydroxide surface area increased, the concentration of colloids in the breakthrough decreased. Model-fits to the experimental data were made by inverse solutions to determine the fraction of surface area favorable for deposition and the deposition rate coefficients for the favorable (ferric oxyhydroxide-coated) and unfavorable sites. The favorable deposition rate coefficient was also calculated by colloid filtration theory. The model described the time to colloid breakthrough and the blocking effect reasonably well and estimated the favorable surface area fraction very well for the two layers with more than 1% ferric oxyhydroxide coating. If mica edges in the uncoated sand were considered as favorable surface area in addition to the ferric oxyhydroxide coatings, the model predicted the favorable surface area fraction accurately for the layer with less than 1% ferric oxyhydroxide coating.

  14. Characterization of heterogeneous reservoirs: sentinels method and quantification of uncertainties; Caracterisation des reservoirs heterogenes: methode des sentinelles et quantification des incertitudes

    Energy Technology Data Exchange (ETDEWEB)

    Mezghani, M.

    1999-02-11

    The aim of this thesis is to propose a new inversion method to allow both an improved reservoir characterization and a management of uncertainties. In this approach, the identification of the permeability distribution is conducted using the sentinel method in order to match the pressure data. This approach, based on optimal control theory, can be seen as an alternative of least-squares method. Here, we prove the existence of exact sentinels under regularity hypothesis. From a numerical point of view, we consider regularized sentinels. We suggest a novel approach to update the penalization coefficient in order to improve numerical robustness. Moreover, the flexibility of the sentinel method enables to develop a way to treat noisy pressure data. To deal with geostatistical modelling of permeability distribution, we propose to link the pilot point method with sentinels to reach the identification of permeability. We particularly focus on the optimal location of pilot points. Finally, we present an original method, based on adjoint state computations, to quantify the dynamic data contribution to the characterisation of a calibrated geostatistical model. (author) 67 refs.

  15. Improved efficiency of miscible CO{sub 2} floods and enhanced prospects for CO{sub 2} flooding heterogeneous reservoirs. Annual report, April 14, 1994--April 13, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Grigg, R.; Heller, J.; Schechter, D.

    1995-09-01

    The overall goal of this project is to improve the efficiency of miscible CO{sub 2} floods and enhance the prospects for flooding heterogeneous reservoirs. This objective is being accomplished by extending experimental research in three task areas: (1) foams for selective mobility control in heterogeneous reservoirs, (2) reduction of the amount of CO{sub 2} required in CO{sub 2} floods, and (3) miscible CO{sub 2} flooding in fractured reservoirs. This report provides results of the first year of the three-year project for each of the three task areas.

  16. Abiotic Dissolution of a Tetrachloroethene (PCE) Pool in an Anaerobic Sand Tank Aquifer System with Heterogeneous Flow

    Science.gov (United States)

    Klemm, Sara; Seagren, Eric; Becker, Jennifer

    2017-04-01

    Intrinsic and engineered in situ bioremediation are made technologically challenging by the physically and chemically heterogeneous nature of the subsurface environment. Subsurface heterogeneities are important because they influence interfacial mass-transfer processes that impact the availability of substrates to the microorganisms. The laboratory experiments reported here examined the dissolution of a dense nonaqueous phase liquid (DNAPL) tetrachloroethene (PCE) pool, and transport of the dissolved PCE plume in a aquifer simulated system with heterogeneous flow. These abiotic experiments were performed in a saturated intermediate-scale flow cell (1.2 m), with flow parallel to the PCE pool. A steady-state mass balance approach was used to estimate the PCE dissolution rate at two different flow rates. As expected, increasing the flow rate decreased the effluent dissolved PCE concentration and increased the dissolution flux. However, the effluent PCE concentration was higher than expected based on modeling predictions assuming a uniform distribution of flow across the depth of the tank. Nonreactive tracer studies confirmed that there was a velocity profile with depth, with the slowest velocity at the top of the tank, and the highest velocity at the bottom of the tank, possible due to consolidation of the sand that occurred during a wetting/drainage cycle. Revised modeling using the vertical flow variation provided an improved prediction of the effluent PCE concentration. These results have important implications for predicting DNAPL pool dissolution in the field. Whereas experimental systems in the laboratory typically employ porous media with uniform flow distribution, flow heterogeneities are the rule rather than the exception in the field, and it is well known that velocity impacts pool dissolution. In the case of this experimental system, the pore water velocity near the pool was greater than the average pore water velocity across the system, resulting in a

  17. Innovative techniques for the description of reservoir heterogeneity using tracers. Second technical annual progress report, October 1991--September 1992

    Energy Technology Data Exchange (ETDEWEB)

    Pope, G.A.; Sepehrnoori, K.

    1992-12-31

    This second annual report on innovative uses of tracers for reservoir characterization contains four sections each describing a novel use of oilfield tracers. The first section describes and illustrates the use of a new single-well tracer test to estimate wettability. This test consists of the injection of brine containing tracers followed by oil containing tracers, a shut-in period to allow some of the tracers to react, and then production of the tracers. The inclusion of the oil injection slug with tracers is unique to this test, and this is what makes the test work. We adapted our chemical simulator, UTCHEM, to enable us to study this tracer method and made an extensive simulation study to evaluate the effects of wettability based upon characteristic curves for relative permeability and capillary pressure for differing wetting states typical of oil reservoirs. The second section of this report describes a new method for analyzing interwell tracer data based upon a type-curve approach. Theoretical frequency response functions were used to build type curves of ``transfer function`` and ``phase spectrum`` that have dimensionless heterogeneity index as a parameter to characterize a stochastic permeability field. We illustrate this method by analyzing field tracer data. The third section of this report describes a new theory for interpreting interwell tracer data in terms of channeling and dispersive behavior for reservoirs. Once again, a stochastic approach to reservoir description is taken. The fourth section of this report describes our simulation of perfluorocarbon gas tracers. This new tracer technology developed at Brookhaven National Laboratory is being tested at the Elk Hills Naval Petroleum Reserve No. 1 in California. We report preliminary simulations made of these tracers in one of the oil reservoirs under evaluation with these tracers in this field. Our compostional simulator (UTCOMP) was used for this simulation study.

  18. Improved efficiency of miscible CO2 floods and enhanced prospects for CO2 flooding heterogeneous reservoirs. Final report, April 17, 1991--May 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Grigg, R.B.; Schechter, D.S.

    1998-02-01

    From 1986 to 1996, oil recovery in the US by gas injection increased almost threefold, to 300,000 bbl/day. Carbon dioxide (CO{sub 2}) injection projects make up three-quarters of the 191,139 bbl/day production increase. This document reports experimental and modeling research in three areas that is increasing the number of reservoirs in which CO{sub 2} can profitably enhance oil recovery: (1) foams for selective mobility reduction (SMR) in heterogeneous reservoirs, (2) reduction of the amount of CO{sub 2} required in CO{sub 2} floods, and (3) low interfacial tension (97) processes and the possibility of CO{sub 2} flooding in naturally fractured reservoirs. CO{sub 2} injection under miscible conditions can effectively displace oil, but due to differences in density and viscosity the mobility of CO{sub 2} is higher than either oil or water. High CO{sub 2} mobility causes injection gas to finger through a reservoir, causing such problems as early gas breakthrough, high gas production rates, excessive injection gas recycling, and bypassing of much of the reservoir oil. These adverse effects are exacerbated by increased reservoir heterogeneity, reaching an extreme in naturally fractured reservoirs. Thus, many highly heterogeneous reservoirs have not been considered for CO{sub 2} injection or have had disappointing recoveries. One example is the heterogeneous Spraberry trend in west Texas, where only 10% of its ten billion barrels of original oil in place (OOIP) are recoverable by conventional methods. CO{sub 2} mobility can be reduced by injecting water (brine) alternated with CO{sub 2} (WAG) and then further reduced by adding foaming agents-surfactants. In Task 1, we studied a unique foam property, selective mobility reduction (SMR), that effectively reduces the effects of reservoir heterogeneity. Selective mobility reduction creates a more uniform displacement by decreasing CO{sub 2} mobility in higher permeability zones more than in lower permeability zones.

  19. AN INTEGRATED APPROACH TO CHARACTERIZING BYPASSED OIL IN HETEROGENEOUS AND FRACTURED RESERVOIRS USING PARTITIONING TRACERS

    Energy Technology Data Exchange (ETDEWEB)

    Akhil Datta-Gupta

    2003-08-01

    We explore the use of efficient streamline-based simulation approaches for modeling partitioning interwell tracer tests in hydrocarbon reservoirs. Specifically, we utilize the unique features of streamline models to develop an efficient approach for interpretation and history matching of field tracer response. A critical aspect here is the underdetermined and highly ill-posed nature of the associated inverse problems. We have adopted an integrated approach whereby we combine data from multiple sources to minimize the uncertainty and non-uniqueness in the interpreted results. For partitioning interwell tracer tests, these are primarily the distribution of reservoir permeability and oil saturation distribution. A novel approach to multiscale data integration using Markov Random Fields (MRF) has been developed to integrate static data sources from the reservoir such as core, well log and 3-D seismic data. We have also explored the use of a finite difference reservoir simulator, UTCHEM, for field-scale design and optimization of partitioning interwell tracer tests. The finite-difference model allows us to include detailed physics associated with reactive tracer transport, particularly those related with transverse and cross-streamline mechanisms. We have investigated the potential use of downhole tracer samplers and also the use of natural tracers for the design of partitioning tracer tests. Finally, the behavior of partitioning tracer tests in fractured reservoirs is investigated using a dual-porosity finite-difference model.

  20. Large to intermediate-scale aquifer heterogeneity in fine-grain dominated alluvial fans (Cenozoic As Pontes Basin, northwestern Spain): insight based on three-dimensional geostatistical reconstruction

    Science.gov (United States)

    Falivene, O.; Cabrera, L.; Sáez, A.

    2007-08-01

    Facies reconstructions are used in hydrogeology to improve the interpretation of aquifer permeability distribution. In the absence of sufficient data to define the heterogeneity due to geological processes, uncertainties in the distribution of aquifer hydrofacies and characteristics may appear. Geometric and geostatistical methods are used to understand and model aquifer hydrofacies distribution, providing models to improve comprehension and development of aquifers. However, these models require some input statistical parameters that can be difficult to infer from the study site. A three-dimensional reconstruction of a kilometer scale fine-grain dominated Cenozoic alluvial fan derived from more than 200 continuously cored, closely spaced, and regularly distributed wells is presented. The facies distributions were reconstructed using a genetic stratigraphic subdivision and a deterministic geostatistical algorithm. The reconstruction is only slightly affected by variations in the geostatistical input parameters because of the high-density data set. Analysis of the reconstruction allowed identification in the proximal to medial alluvial fan zones of several laterally extensive sand bodies with relatively higher permeability; these sand bodies were quantified in terms of volume, mean thickness, maximum area, and maximum equivalent diameter. These quantifications provide trends and geological scenarios for input statistical parameters to model aquifer systems in similar alluvial fan depositional settings.

  1. Characterization of oil and gas reservoir heterogeneity. Annual report, November 1, 1990--October 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    The objective of the cooperative research program is to characterize Alaskan reservoirs in terms of their reserves, physical and chemical properties, geologic configuration and structure, and the development potential. The tasks completed during this period include: (1) geologic reservoir description of Endicott Field; (2) petrographic characterization of core samples taken from selected stratigraphic horizons of the West Sak and Ugnu (Brookian) wells; (3) development of a polydispersed thermodynamic model for predicting asphaltene equilibria and asphaltene precipitation from crude oil-solvent mixtures, and (4) preliminary geologic description of the Milne Point Unit.

  2. A conceptual sedimentological-geostatistical model of aquifer heterogeneity based on outcrop studies

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.M.

    1994-01-01

    Three outcrop studies were conducted in deposits of different depositional environments. At each site, permeability measurements were obtained with an air-minipermeameter developed as part of this study. In addition, the geological units were mapped with either surveying, photographs, or both. Geostatistical analysis of the permeability data was performed to estimate the characteristics of the probability distribution function and the spatial correlation structure. The information obtained from the geological mapping was then compared with the results of the geostatistical analysis for any relationships that may exist. The main field site was located in the Albuquerque Basin of central New Mexico at an outcrop of the Pliocene-Pleistocene Sierra Ladrones Formation. The second study was conducted on the walls of waste pits in alluvial fan deposits at the Nevada Test Site. The third study was conducted on an outcrop of an eolian deposit (miocene) south of Socorro, New Mexico. The results of the three studies were then used to construct a conceptual model relating depositional environment to geostatistical models of heterogeneity. The model presented is largely qualitative but provides a basis for further hypothesis formulation and testing.

  3. A conceptual sedimentological-geostatistical model of aquifer heterogeneity based on outcrop studies

    International Nuclear Information System (INIS)

    Davis, J.M.

    1994-01-01

    Three outcrop studies were conducted in deposits of different depositional environments. At each site, permeability measurements were obtained with an air-minipermeameter developed as part of this study. In addition, the geological units were mapped with either surveying, photographs, or both. Geostatistical analysis of the permeability data was performed to estimate the characteristics of the probability distribution function and the spatial correlation structure. The information obtained from the geological mapping was then compared with the results of the geostatistical analysis for any relationships that may exist. The main field site was located in the Albuquerque Basin of central New Mexico at an outcrop of the Pliocene-Pleistocene Sierra Ladrones Formation. The second study was conducted on the walls of waste pits in alluvial fan deposits at the Nevada Test Site. The third study was conducted on an outcrop of an eolian deposit (miocene) south of Socorro, New Mexico. The results of the three studies were then used to construct a conceptual model relating depositional environment to geostatistical models of heterogeneity. The model presented is largely qualitative but provides a basis for further hypothesis formulation and testing

  4. Methicillin-Resistant Coagulase-Negative Staphylococci on Pig Farms as a Reservoir of Heterogeneous Staphylococcal Cassette Chromosome mec Elements

    Science.gov (United States)

    Tulinski, Pawel; Fluit, Ad C.; Wagenaar, Jaap A.; Mevius, Dik; van de Vijver, Lucy

    2012-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) likely originated by acquisition of the staphylococcal cassette chromosome mec (SCCmec) from coagulase-negative staphylococci (CNS). However, it is unknown whether the same SCCmec types are present in MRSA and CNS that reside in the same niche. Here we describe a study to determine the presence of a potential mecA reservoir among CNS recovered from 10 pig farms. The 44 strains belonged to 10 different Staphylococcus species. All S. aureus strains belonged to sequence type 398 (ST398), with SCCmec types V and IVa. Type IVc, as well as types III and VI, novel subtypes of type IV, and not-typeable types, were found in CNS. S. aureus, S. epidermidis, and S. haemolyticus shared SCCmec type V. The presence of SCCmec type IVc in several staphylococcal species isolated from one pig farm is noteworthy, suggesting exchange of this SCCmec type in CNS, but the general distribution of this SCCmec type still has to be established. In conclusion, this study shows that SCCmec types among staphylococcal species on pig farms are heterogeneous. On two farms, more than one recovered staphylococcal species harbored the same SCCmec type. We conclude that staphylococci on pig farms act as a reservoir of heterogeneous SCCmec elements. These staphylococci may act as a source for transfer of SCCmec to S. aureus. PMID:22081567

  5. Longitudinal heterogeneity of phosphorus and phytoplankton concentrations in deep-valley reservoirs

    Czech Academy of Sciences Publication Activity Database

    Hejzlar, Josef; Vyhnálek, Vojtěch

    1998-01-01

    Roč. 83, Special Issue (1998), s. 139-146 ISSN 1434-2944. [International Conference on Reservoir Limnology and Water Quality /3./. České Budějovice, 11.08.1997-15.08.1997] R&D Projects: GA ČR GA103/96/1710; GA AV ČR IAA2060504 Subject RIV: DA - Hydrology ; Limnology Impact factor: 0.632, year: 1997

  6. Use of ``rock-typing`` to characterize carbonate reservoir heterogeneity. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ikwuakor, K.C.

    1994-03-01

    The objective of the project was to apply techniques of ``rock-typing`` and quantitative formation evaluation to borehole measurements in order to identify reservoir and non-reservoir rock-types and their properties within the ``C`` zone of the Ordovician Red River carbonates in the northeast Montana and northwest North Dakota areas of the Williston Basin. Rock-typing discriminates rock units according to their pore-size distribution. Formation evaluation estimates porosities and pore fluid saturation. Rock-types were discriminated using crossplots involving three rock-typing criteria: (1) linear relationship between bulk density and porosity, (2) linear relationship between acoustic interval transit-time and porosity, and (3) linear relationship between acoustic interval transit-time and bulk density. Each rock-type was quantitatively characterized by the slopes and intercepts established for different crossplots involving the above variables, as well as porosities and fluid saturations associated with the rock-types. All the existing production was confirmed through quantitative formation evaluation. Highly porous dolomites and anhydritic dolomites contribute most of the production, and constitute the best reservoir rock-types. The results of this study can be applied in field development and in-fill drilling. Potential targets would be areas of porosity pinchouts and those areas where highly porous zones are downdip from non-porous and tight dolomites. Such areas are abundant. In order to model reservoirs for enhanced oil recovery (EOR) operations, a more localized (e.g. field scale) study, expanded to involve other rock-typing criteria, is necessary.

  7. Reactive transport impacts on recovered freshwater quality during multiple partially penetrating wells (MPPW-)ASR in a brackish heterogeneous aquifer

    NARCIS (Netherlands)

    Zuurbier, Koen G.; Hartog, Niels; Stuyfzand, Pieter J.

    The use of multiple partially penetrating wells (MPPW) during aquifer storage and recovery (ASR) in brackish aquifers can significantly improve the recovery efficiency (RE) of unmixed injected water. The water quality changes by reactive transport processes in a field MPPW-ASR system and their

  8. The Role of Horizontal Wells when Developing Low-Permeable, Heterogeneous Reservoirs

    Directory of Open Access Journals (Sweden)

    M.P. Yurova

    2017-09-01

    Full Text Available The widespread use of horizontal drilling in recent years has shown that horizontal wells can be successfully used both at the initial and late stages of development. This is due to the fact that horizontal wells, in contrast to vertical wells, contact a larger area of ​​the productive formation, while the surface of drainage of the oil-saturated layer, productivity of the wells due to the formation of cracks, and also the influence on thin layers increases. One of the methods of impact on the reservoir is the steam-thermal method. The main advantage of the use of the heat wave method in horizontal wells is a significant increase in the well production rate, a decrease in the water cut of the reservoir, a decrease in the oil viscosity, an increase in the injectivity of the injection well, and an increase in the inflow in producing wells. As a result of the total effect, a significant increase in production is obtained throughout the entire deposit. Enhanced oil recovery from the injection of steam is achieved by reducing the viscosity of oil, covering the reservoir with steam, distilling oil and extracting with a solvent. All this increases the displacement coefficient. One of the most effective ways to increase oil recovery at a late stage of field operation is sidetracking in emergency, highly watered and low-productive wells. This leads to the development of residual reserves in weakly drained zones of reservoirs with a substantial increase in well productivity in low-permeable reservoirs. This approach assumes that the initial drilling of wells is a ‘pilot’ stage, which precedes the development of oil reserves in the late stages of deposit development. In the fields of Western Siberia, multiple hydraulic fracturing of the reservoir has been improved due to a special stinger in the liner hanger of multi-packer installation, which excludes the influence of high pressures on the production column under the multiple hydraulic fracturing

  9. The effects of thermomechanical heterogeneities in island arc crust on time-dependent preeruptive stresses and the failure of an andesitic reservoir

    Science.gov (United States)

    Gottsmann, J.; Odbert, H.

    2014-06-01

    Using ground deformation data from Soufrière Hills volcano (SHV), we present results from numerical modeling of the temperature- and time-dependent stress evolution in a mechanically heterogeneous crust prior to reservoir failure and renewed eruptive activity. The best fit models do not allow us to discriminate between a magmatic plumbing system consisting of either a single vertically elongated reservoir or a series of stacked reservoirs. A prolate reservoir geometry with volumes between 50 and 100 km3, reservoir pressure changes between 4 and 7 MPa, and reservoir volume changes between 0.03 and 0.04 km3 with magma compressibility between 4 × 10-11 and 1 × 10-9 Pa-1 provide plausible thermomechanical model parameters to explain the deformation time series; around an order of magnitude less overpressure than is generally inferred from homogeneous, elastic crustal models. Reservoir failure is predicted to occur at the crest of the reservoir except for reservoirs with highly compressible magma (≳4×10-9 Pa) for which subhorizontal sill formation is predicted upon reservoir failure. Introducing a deep-crustal hot zone modulates the partitioning of strains into the hotter underlying crust and results in a further reduction in overpressure estimates to values of around 1-2 MPa upon reservoir failure. Deduced volume fluxes are consistent with constraints from thermal modeling of active subvolcanic systems and imply dynamic failure of a compressible magma mush column feeding eruptions at SHV. Our interpretation of the results is that the combined thermomechanical effects of a deep-crustal hot zone and hot encasing rocks around a midcrustal andesitic reservoir fundamentally alter the time-dependent subsurface stress and strain partitioning upon reservoir priming. These effects substantially influence surface strains recorded by volcano geodetic monitoring.

  10. An Integrated Approach to Characterizing Bypassed Oil in Heterogeneous and Fractured Reservoirs Using Partitioning Tracers. Annual Report

    International Nuclear Information System (INIS)

    Akhil Datta-Gupta

    2006-01-01

    This report presents an efficient trajectory-based approach to integrate transient pressure data into high-resolution reservoir and aquifer models. The method involves alternating travel time and peak amplitude matching of pressure response using inverse modeling and is particularly well-suited for high resolution subsurface characterization using hydraulic tomography or pressure interference tests. Compared to travel time inversion only, our proposed approach results in a significantly improved match of the pressure response at the wells and also better estimates of subsurface properties. This is accomplished with very little increase in computational cost. Utilizing the concept of a ''diffusive'' time of flight derived from an asymptotic solution of the diffusivity equation, we develop analytical approaches to estimate the sensitivities for travel time and peak amplitude of pressure response to subsurface properties. The sensitivities are then used in an iterative least-squared minimization to match the pressure data. We illustrate our approach using synthetic and field examples. In the field application at a fractured limestone formation, the predominant fracture patterns emerging from the inversion are shown to be consistent with independent geophysical experiments and borehole data

  11. Experimental investigation of geochemical and mineralogical effects of CO2 sequestration on flow characteristics of reservoir rock in deep saline aquifers

    Science.gov (United States)

    Rathnaweera, T. D.; Ranjith, P. G.; Perera, M. S. A.

    2016-01-01

    Interactions between injected CO2, brine, and rock during CO2 sequestration in deep saline aquifers alter their natural hydro-mechanical properties, affecting the safety, and efficiency of the sequestration process. This study aims to identify such interaction-induced mineralogical changes in aquifers, and in particular their impact on the reservoir rock’s flow characteristics. Sandstone samples were first exposed for 1.5 years to a mixture of brine and super-critical CO2 (scCO2), then tested to determine their altered geochemical and mineralogical properties. Changes caused uniquely by CO2 were identified by comparison with samples exposed over a similar period to either plain brine or brine saturated with N2. The results show that long-term reaction with CO2 causes a significant pH drop in the saline pore fluid, clearly due to carbonic acid (as dissolved CO2) in the brine. Free H+ ions released into the pore fluid alter the mineralogical structure of the rock formation, through the dissolution of minerals such as calcite, siderite, barite, and quartz. Long-term CO2 injection also creates a significant CO2 drying-out effect and crystals of salt (NaCl) precipitate in the system, further changing the pore structure. Such mineralogical alterations significantly affect the saline aquifer’s permeability, with important practical consequences for the sequestration process. PMID:26785912

  12. Comparison of stochastic and regression based methods for quantification of predictive uncertainty of model-simulated wellhead protection zones in heterogeneous aquifers

    DEFF Research Database (Denmark)

    Christensen, Steen; Moore, C.; Doherty, J.

    2006-01-01

    accurate and required a few hundred model calls to be computed. (b) The linearized regression-based interval (Cooley, 2004) required just over a hundred model calls and also appeared to be nearly correct. (c) The calibration-constrained Monte-Carlo interval (Doherty, 2003) was found to be narrower than......For a synthetic case we computed three types of individual prediction intervals for the location of the aquifer entry point of a particle that moves through a heterogeneous aquifer and ends up in a pumping well. (a) The nonlinear regression-based interval (Cooley, 2004) was found to be nearly...... the regression-based intervals but required about half a million model calls. It is unclear whether or not this type of prediction interval is accurate....

  13. Integration of advanced geoscience and engineering techniques to quantify interwell heterogeneity in reservoir models. Final report, September 29, 1993--September 30, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, W.W.; Buckley, J.S.; Ouenes, A.

    1997-05-01

    The goal of this three-year project was to provide a quantitative definition of reservoir heterogeneity. This objective was accomplished through the integration of geologic, geophysical, and engineering databases into a multi-disciplinary understanding of reservoir architecture and associated fluid-rock and fluid-fluid interactions. This interdisciplinary effort integrated geological and geophysical data with engineering and petrophysical results through reservoir simulation to quantify reservoir architecture and the dynamics of fluid-rock and fluid-fluid interactions. An improved reservoir description allows greater accuracy and confidence during simulation and modeling as steps toward gaining greater recovery efficiency from existing reservoirs. A field laboratory, the Sulimar Queen Unit, was available for the field research. Several members of the PRRC staff participated in the development of improved reservoir description by integration of the field and laboratory data as well as in the development of quantitative reservoir models to aid performance predictions. Subcontractors from Stanford University and the University of Texas at Austin (UT) collaborated in the research and participated in the design and interpretation of field tests. The three-year project was initiated in September 1993 and led to the development and application of various reservoir description methodologies. A new approach for visualizing production data graphically was developed and implemented on the Internet. Using production data and old gamma rays logs, a black oil reservoir model that honors both primary and secondary performance was developed. The old gamma ray logs were used after applying a resealing technique, which was crucial for the success of the project. In addition to the gamma ray logs, the development of the reservoir model benefitted from an inverse Drill Stem Test (DST) technique which provided initial estimates of the reservoir permeability at different wells.

  14. Multinomial Logistic Regression & Bootstrapping for Bayesian Estimation of Vertical Facies Prediction in Heterogeneous Sandstone Reservoirs

    Science.gov (United States)

    Al-Mudhafar, W. J.

    2013-12-01

    Precisely prediction of rock facies leads to adequate reservoir characterization by improving the porosity-permeability relationships to estimate the properties in non-cored intervals. It also helps to accurately identify the spatial facies distribution to perform an accurate reservoir model for optimal future reservoir performance. In this paper, the facies estimation has been done through Multinomial logistic regression (MLR) with respect to the well logs and core data in a well in upper sandstone formation of South Rumaila oil field. The entire independent variables are gamma rays, formation density, water saturation, shale volume, log porosity, core porosity, and core permeability. Firstly, Robust Sequential Imputation Algorithm has been considered to impute the missing data. This algorithm starts from a complete subset of the dataset and estimates sequentially the missing values in an incomplete observation by minimizing the determinant of the covariance of the augmented data matrix. Then, the observation is added to the complete data matrix and the algorithm continues with the next observation with missing values. The MLR has been chosen to estimate the maximum likelihood and minimize the standard error for the nonlinear relationships between facies & core and log data. The MLR is used to predict the probabilities of the different possible facies given each independent variable by constructing a linear predictor function having a set of weights that are linearly combined with the independent variables by using a dot product. Beta distribution of facies has been considered as prior knowledge and the resulted predicted probability (posterior) has been estimated from MLR based on Baye's theorem that represents the relationship between predicted probability (posterior) with the conditional probability and the prior knowledge. To assess the statistical accuracy of the model, the bootstrap should be carried out to estimate extra-sample prediction error by randomly

  15. An Integrated Approach to Characterizing Bypassed Oil in Heterogeneous and Fractured Reservoirs Using Partitioning Tracers

    Energy Technology Data Exchange (ETDEWEB)

    Akhil Datta-Gupta

    2006-12-31

    We explore the use of efficient streamline-based simulation approaches for modeling partitioning interwell tracer tests in hydrocarbon reservoirs. Specifically, we utilize the unique features of streamline models to develop an efficient approach for interpretation and history matching of field tracer response. A critical aspect here is the underdetermined and highly ill-posed nature of the associated inverse problems. We have investigated the relative merits of the traditional history matching ('amplitude inversion') and a novel travel time inversion in terms of robustness of the method and convergence behavior of the solution. We show that the traditional amplitude inversion is orders of magnitude more non-linear and the solution here is likely to get trapped in local minimum, leading to inadequate history match. The proposed travel time inversion is shown to be extremely efficient and robust for practical field applications. The streamline approach is generalized to model water injection in naturally fractured reservoirs through the use of a dual media approach. The fractures and matrix are treated as separate continua that are connected through a transfer function, as in conventional finite difference simulators for modeling fractured systems. A detailed comparison with a commercial finite difference simulator shows very good agreement. Furthermore, an examination of the scaling behavior of the computation time indicates that the streamline approach is likely to result in significant savings for large-scale field applications. We also propose a novel approach to history matching finite-difference models that combines the advantage of the streamline models with the versatility of finite-difference simulation. In our approach, we utilize the streamline-derived sensitivities to facilitate history matching during finite-difference simulation. The use of finite-difference model allows us to account for detailed process physics and compressibility effects

  16. Response of Daphnia's antioxidant system to spatial heterogeneity in Cyanobacteria concentrations in a lowland reservoir.

    Directory of Open Access Journals (Sweden)

    Adrianna Wojtal-Frankiewicz

    Full Text Available Many species and clones of Daphnia inhabit ecosystems with permanent algal blooms, and they can develop tolerance to cyanobacterial toxins. In the current study, we examined the spatial differences in the response of Daphnia longispina to the toxic Microcystis aeruginosa in a lowland eutrophic dam reservoir between June (before blooms and September (during blooms. The reservoir showed a distinct spatial pattern in cyanobacteria abundance resulting from the wind direction: the station closest to the dam was characterised by persistently high Microcystis biomass, whereas the upstream stations had a significantly lower biomass of Microcystis. Microcystin concentrations were closely correlated with the cyanobacteria abundance (r = 0.93. The density of daphniids did not differ among the stations. The main objective of this study was to investigate how the distribution of toxic Microcystis blooms affects the antioxidant system of Daphnia. We examined catalase (CAT activity, the level of the low molecular weight antioxidant glutathione (GSH, glutathione S-transferase (GST activity and oxidative stress parameters, such as lipid peroxidation (LPO. We found that the higher the abundance (and toxicity of the cyanobacteria, the lower the values of the antioxidant parameters. The CAT activity and LPO level were always significantly lower at the station with the highest M. aeruginosa biomass, which indicated the low oxidative stress of D. longispina at the site with the potentially high toxic thread. However, the low concentration of GSH and the highest activity of GST indicated the occurrence of detoxification processes at this site. These results demonstrate that daphniids that have coexisted with a high biomass of toxic cyanobacteria have effective mechanisms that protect them against the toxic effects of microcystins. We also conclude that Daphnia's resistance capacity to Microcystis toxins may differ within an ecosystem, depending on the bloom

  17. Détermination du temps de résidence des eaux souterraines : application au transfert d'azote dans les aquifères fracturés hétérogènes

    OpenAIRE

    Ayraud , Virginie

    2005-01-01

    Heterogeneous fractured aquifers are extensively developed in crystalline rocks, such as schistor granite. In these aquifers, porosity ranges from the fractures to the microporosity containedin pores and fissures of the matrix. A better characterisation of such aquifers and especiallyadapted to search for new water reservoir in Brittany, was undertaken through: (1) temporalchronicles, isotopic analyses and laboratory experiments and (2) by the interpretation ofresidence times through CFC anal...

  18. HIGH RESOLUTION PREDICTION OF GAS INJECTION PROCESS PERFORMANCE FOR HETEROGENEOUS RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Franklin M. Orr, Jr.

    2003-06-30

    This report presents a detailed analysis of the development of miscibility during gas cycling in condensates and the formation of condensate banks at the leading edge of the displacement front. Dispersion-free, semi-analytical one-dimensional (1D) calculations are presented for enhanced condensate recovery by gas injection. The semi-analytical approach allows investigation of the possible formation of condensate banks (often at saturations that exceed the residual liquid saturation) and also allows fast screening of optimal injection gas compositions. We describe construction of the semi-analytical solutions, a process which differs in some ways from related displacements for oil systems. We use an analysis of key equilibrium tie lines that are part of the displacement composition path to demonstrate that the mechanism controlling the development of miscibility in gas condensates may vary from first-contact miscible drives to pure vaporizing and combined vaporizing/condensing drives. Depending on the compositions of the condensate and the injected gas, multicontact miscibility can develop at the dew point pressure, or below the dew point pressure of the reservoir fluid mixture. Finally, we discuss the possible impact on performance prediction of the formation of a mobile condensate bank at the displacement front in near-miscible gas cycling/injection schemes.

  19. The influence of facies heterogeneity on the doublet performance in low-enthalpy geothermal sedimentary reservoirs

    DEFF Research Database (Denmark)

    Crooijmans, R. A.; Willems, C. J L; Nick, Hamid

    2016-01-01

    A three-dimensional model is used to study the influence of facies heterogeneity on energy production under different operational conditions of low-enthalpy geothermal doublet systems. Process-based facies modelling is utilised for the Nieuwerkerk sedimentary formation in the West Netherlands Basin...... and the energy recovery rate for different discharge rates and the production temperature (Tmin) above which the doublet is working. With respect to the results, we propose a design model to estimate the life time and energy recovery rate of the geothermal doublet. The life time is estimated as a function of N...... errors in predicting the life time of low-enthalpy geothermal systems for N/G values below 70%....

  20. Apport de la géostatistique à la description des stockages de gaz en aquifère Contribution of Geostatistics to Describing Aquifer Gas-Storage Reservoirs

    Directory of Open Access Journals (Sweden)

    Delhomme J. P.

    2006-11-01

    Full Text Available L'étude du comportement d'un réservoir de gaz en nappe aquifère réclame une connaissance aussi précise que possible des caractéristiques géométriques et pétrophysiques des couches réservoirs. Les moyens d'investigation sont de deux natures : - forages permettant une connaissance locale des roches réservoirs ; - mesures sismiques conduisant à une estimation approximative des cotes de certains repères stratigraphiques, en des points situés le long de profils. Les données recueillies sont donc, par nature, fragmentaires et discrètes : là où elles sont absentes, il y a lieu d'estimer les grandeurs étudiées en tenant compte au mieux de notre connaissance de leur variabilité spatiale. Ce problème d'interpolation optimale a donné lieu, depuis une vingtaine d'années, à l'élaboration et la mise en pratique d'un outil théorique particulièrement bien adapté aux besoins exprimés par les techniciens des sciences de la terre : la théorie des variables régionalisées due à G. Matheron. Des programmes informatiques mettant en oeuvre cette théorie sont actuellement opérationnels. Des exemples d'application en sont donnés : - tracé automatique de cartes structurales à partir des données de forages et des mesures sismiques ; - estimation des incertitudes de prévision sur les profondeurs ; - tracé de plusieurs variantes de carte compatibles avec les données ; - établissement d'éléments statistiques relatifs à une grandeur caractéristique d'un stockage : volume stockable par exemple ; - génération automatique des données nécessaires à la mise en oeuvre d'un modèle maillé de réservoir. Predicting and monitoring the behavior of an aquifer gas-storage reservoir requires as precise a knowledge as possible of the geometric and petrophysical properties of the reservoir layer. Two ways of obtaining this information can be given: (a Boreholes which provide local knowledge of the reservoir, and (b Seismic measurements

  1. Probabilistic human health risk assessment of degradation-related chemical mixtures in heterogeneous aquifers: Risk statistics, hot spots, and preferential channels

    Science.gov (United States)

    Henri, Christopher V.; Fernàndez-Garcia, Daniel; de Barros, Felipe P. J.

    2015-06-01

    The increasing presence of toxic chemicals released in the subsurface has led to a rapid growth of social concerns and the need to develop and employ models that can predict the impact of groundwater contamination on human health risk under uncertainty. Monitored natural attenuation is a common remediation action in many contamination cases. However, natural attenuation can lead to the production of daughter species of distinct toxicity that may pose challenges in pollution management strategies. The actual threat that these contaminants pose to human health depends on the interplay between the complex structure of the geological media and the toxicity of each pollutant byproduct. This work addresses human health risk for chemical mixtures resulting from the sequential degradation of a contaminant (such as a chlorinated solvent) under uncertainty through high-resolution three-dimensional numerical simulations. We systematically investigate the interaction between aquifer heterogeneity, flow connectivity, contaminant injection model, and chemical toxicity in the probabilistic characterization of health risk. We illustrate how chemical-specific travel times control the regime of the expected risk and its corresponding uncertainties. Results indicate conditions where preferential flow paths can favor the reduction of the overall risk of the chemical mixture. The overall human risk response to aquifer connectivity is shown to be nontrivial for multispecies transport. This nontriviality is a result of the interaction between aquifer heterogeneity and chemical toxicity. To quantify the joint effect of connectivity and toxicity in health risk, we propose a toxicity-based Damköhler number. Furthermore, we provide a statistical characterization in terms of low-order moments and the probability density function of the individual and total risks.

  2. Experimental and modeling results on geochemical impacts of leaking CO2 from subsurface storage reservoirs to an unconfined oxidizing carbonate aquifer

    Science.gov (United States)

    Qafoku, N. P.; Bacon, D. H.; Shao, H.; Lawter, A.; Wang, G.; Brown, C. F.

    2013-12-01

    Deep subsurface storage and sequestration of CO2 has been identified as a potential mitigation technique for rising atmospheric CO2 concentrations. Sequestered CO2 represents a potential risk to overlying aquifers if the CO2 leaks from the deep storage reservoir. Experimental and modeling work is required to evaluate risks to groundwater quality and develop a systematic understanding on how CO2 leakage may cause important changes in aquifer chemistry and mineralogy by promoting dissolution/precipitation, adsorption/desorption, and redox reactions. Solid materials (rocks and slightly weathered rocks) from an unconfined aquifer, i.e., the Edwards Aquifer in Texas, were used in this investigation. The experimental part consisted of: 1) wet chemical acid extractions (8M HNO3 solution at 90 0C); 2) batch experiments conducted at low solid to solution ratios to study time-dependent releases of major, minor and trace elements during periodic or continuous exposure to CO2 gas; 3) hydraulically saturated column experiments conducted under continuous and stop-flow conditions using a CO2 gas saturated synthetic groundwater; 4) pre- and post-treatment solid phase characterization studies. Major variables tested included reaction time (0-336 hours), CO2 flow rate (50 to 350 ml/min), brine concentration (0.1 and 1 M NaCl), rock type and particle size fraction. We are currently investigating the solution composition effects (i.e., presence of contaminants in the initial solution) on the fate and behavior of potential contaminants (As, Pb and Cd) in these systems. Results from the solid phase characterization studies showed that the mineralogy of the Edwards aquifer materials was dominated by calcite. Quartz and montmorillonite were also present in some samples. Acid extractions confirmed that the solid phase had appreciable amounts of potential contaminants (As, Cd, Cr, Cu, Pb and Zn). However, the results from the batch and column experiments demonstrated that these contaminants

  3. Improved efficiency of miscible CO{sub 2} floods and enhanced prospects for CO{sub 2} flooding heterogeneous reservoirs. Annual report, April 18, 1995--April 17, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Grigg, R.B.; Schechter, D.S.

    1996-10-01

    The overall goal of this project is to improve the efficiency of miscible CO{sub 2} floods and enhance the prospects for flooding heterogeneous reservoirs. This objective is being accomplished by extending experimental and modeling research in three task areas: (1) foams for selective mobility control in heterogeneous reservoirs, (2) reduction of the amount of CO{sub 2} required in CO{sub 2} floods, and (3) low IFT processes and the possibility of CO{sub 2} flooding in fractured reservoirs. This report provides results of the second year of the three-year project for each of the three task areas. In the first task, we are investigating a desirable characteristic of CO{sub 2}-foam called Selective Mobility Reduction (SMR) that results in an improvement in displacement efficiency by reducing the effects of reservoir heterogeneity. Research on SMR of foam during the past year has focused on three subjects: (1) to verify SMR in different rock permeabilities that are in capillary contact; (2) to test additional surfactants for the SMR property; and (3) to develop a modeling approach to assess the oil recovery efficiency of SMR in CO{sub 2}-foam on a reservoir scale. The experimental results from the composite cores suggest that the rock heterogeneity has significant effect on two phase (CO{sub 2}/brine) flow behavior in porous media, and that foam can favorably control CO{sub 2} mobility. The numerical modeling results suggest that foam with SMR can substantially increase the sweep efficiency and therefore improve oil recovery.

  4. Flooding of the Saar-Lorraine Coal Mines: coupling of the regional model of the lower triassic sandstones aquifer with a 'box' model of the mining reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Babot, Y.; Duzan, A. [ANTEA, Parc Club des Tanneries, 67 - Tanneries (France); Eckart, M.; Kories, H. [Deutsche Montan Technologie GmbH, Essen (Germany); Metz, M. [Charbonnages de France GSA, 57 - Freyming-Merlebach (France); Rengers, R. [Deutsche Steinkohle AG, Herne (Germany)

    2005-07-01

    Charbonnages de France (CdF) and Deutsche Steinkohle AG (DSK) has mandated the ANTEA/DMT working group to draw up a trans-border groundwater / mining reservoir coupling model for the Center-East sector. This coupling makes it possible to calculate pumping flows, according to pressure losses between mines, in order to prevent brackish water intrusion from mines to the Lower Triassic Sandstones aquifer. (author000.

  5. First-order based cumulative distribution function for solute concentration in heterogeneous aquifers: Theoretical analysis and implications for human health risk assessment

    Science.gov (United States)

    de Barros, F. P. J.; Fiori, A.

    2014-05-01

    Quantifying the uncertainty of solute concentration in heterogeneous aquifers is an important step in both human health and ecological risk analysis. The need for a probabilistic representation of transport is justified by the incomplete characterization of the subsurface. We derive the one-point concentration cumulative distribution function (CDF) while taking into account the spatial statistical structure of the hydraulic conductivity, space dimensionality, the injection source size, the Péclet number, and the sampling volume at the monitoring location. The CDF is application oriented and derived at first order in the log-conductivity variance. We illustrate how several key parameters control the shape of the concentration CDF. The CDF shape is important since it reflects both uncertainty and the dilution state of the plume. The transition from a bimodal to a unimodal CDF is examined and results are further supported by analyzing the concentration coefficient of variation. Results indicate the significance of the statistical anisotropy ratio (i.e., the ratio between the hydraulic conductivity correlation scales) in determining the CDF shape. The importance of the sampling volume in the tails of the concentration CDF and a comparison between the proposed model with the β-CDF approach (i.e., beta distribution) are also shown. Finally, we illustrate how the framework could be used in applications by evaluating the human health risk CDF. Our results are formally valid for low to moderate heterogeneous aquifers and source sizes small as compared to the hydraulic conductivity correlation length. The proposed approach can serve as a benchmark tool for other methods.

  6. Three-dimensional Inversion of High Resolution Ground-penetrating Radar for the Stochastic Structure of Velocity Heterogeneity of a Fluvial Aquifer

    Science.gov (United States)

    Lindsay, K. M.; Irving, J.; Bradford, J. H.

    2014-12-01

    Knowledge of the spatial correlation structure of the hydraulic properties in the shallow subsurface is critical for the detailed characterization of near surface aquifers and realistic simulation of flow and transport processes. While the vertical correlation structure is often well constrained by borehole analysis, the lateral correlation structure is often poorly estimated, due to unreliable interpolation between sparsely spaced boreholes and methods that only capture bulk aquifer properties (e.g. pump tests, slug injections). Ground-penetrating radar (GPR) velocity measurements are highly sensitive to changes in water content. In the saturated zone, water content is equivalent to porosity, making ground-penetrating radar a promising tool for extraction of lateral correlation lengths of important hydrologic properties in the near surface. Previous work has shown that there is a simple relationship relating the 2D autocorrelation of a GPR reflection image and the underlying velocity field, allowing for a Monte Carlo inversion strategy to generate sets of parameters describing the autocorrelation of the velocity field, that are consistent with recorded GPR reflection data. We extend this method to the three-dimensional case and apply it to a realistic synthetic GPR dataset. Results obtained from applying this inversion strategy to the 3-D case are similar to the results from previous work done on the 2-D case, and indicate that the inverse solution is non-unique. Multiple combinations of vertical and lateral correlation parameters describing the velocity heterogeneity can generate GPR reflection images with the same 3-D autocorrelations. Despite the non-uniqueness, the aspect ratios of the extracted parameter pairs are the same, indicating that the aspect ratios of the velocity heterogeneity can be reliably extracted. We are currently applying this method to a densely sampled GPR dataset collected at the Boise Hydrogeophysical Research Site (BHRS). The BHRS is an

  7. Stochastic joint inversion of geoelectrical cross-well data for salt tracer test monitoring to image the hydraulic conductivity field of heterogenous aquifers

    Science.gov (United States)

    Revil, A.; Jardani, A.; Dupont, J.

    2012-12-01

    The assessment of hydraulic conductivity of heterogeneous aquifers is a difficult task using traditional hydrogeological methods (e.g., steady state or transient pumping tests) due to their low spatial resolution associated with a low density of available piezometers. Geophysical measurements performed at the ground surface and in boreholes provide additional information for increasing the resolution and accuracy of the inverted hydraulic conductivity. We use a stochastic joint inversion of Direct Current (DC) resistivity and Self-Potential (SP) data plus in situ measurement of the salinity in a downstream well during a synthetic salt tracer experiment to reconstruct the hydraulic conductivity field of an heterogeneous aquifer. The pilot point parameterization is used to avoid over-parameterization of the inverse problem. Bounds on the model parameters are used to promote a consistent Markov chain Monte Carlo sampling of the hydrogeological parameters of the model. To evaluate the effectiveness of the inversion process, we compare several scenarios where the geophysical data are coupled or not to the hydrogeological data to map the hydraulic conductivity. We first test the effectiveness of the inversion of each type of data alone, and then we combine the methods two by two. We finally combine all the information together to show the value of each type of geophysical data in the joint inversion process because of their different sensitivity map. The results of the inversion reveal that the self-potential data improve the estimate of hydraulic conductivity especially when the self-potential data are combined to the salt concentration measurement in the second well or to the time-lapse electrical resistivity data. Various tests are also performed to quantify the uncertainty in the inversion when for instance the semi-variogram is not known and its parameters should be inverted as well.

  8. Technical comment on: "On the stochastic theory of solute transport by unsteady and steady groundwater flow in heterogeneous aquifers", by M.L. Kavvas and A. Karakas (Journal of Hydrology Vol. 179 (1996) 321-351)

    Science.gov (United States)

    Kabalaa, Z. J.; Sposito, Garrison

    1998-06-01

    In this note, we demonstrate that statements made in a recent paper by Kavvas and Karakas (1996) (J. Hydrol., 179: 321-351), concerning the assumptions underlying the stochastic model of solute transport in spatially-heterogeneous aquifers developed by Kabala and Sposito (1991) (Water Resour. Res., 25: 341-350), are incorrect.

  9. Modeling CO2 Sequestration in Saline Aquifer and Depleted Oil Reservoir To Evaluate Regional CO2 Sequestration Potential of Ozark Plateau Aquifer System, South-Central Kansas

    Energy Technology Data Exchange (ETDEWEB)

    Watney, W. Lynn [University Of Kansas Center For Research, Inc. Lawrence, KS (United States)

    2014-09-30

    1. Drilled, cored, and logged three wells to the basement and collecting more than 2,700 ft of conventional core; obtained 20 mi2 of multicomponent 3D seismic imaging and merged and reprocessed more than 125 mi2 of existing 3D seismic data for use in modeling CO2- EOR oil recovery and CO2 storage in five oil fields in southern Kansas. 2. Determined the technical feasibility of injecting and sequestering CO2 in a set of four depleted oil reservoirs in the Cutter, Pleasant Prairie South, Eubank, and Shuck fields in southwest Kansas; of concurrently recovering oil from those fields; and of quantifying the volumes of CO2 sequestered and oil recovered during the process. 3. Formed a consortium of six oil operating companies, five of which own and operate the four fields. The consortium became part of the Southwest Kansas CO2-EOR Initiative for the purpose of sharing data, knowledge, and interest in understanding the potential for CO2-EOR in Kansas. 4. Built a regional well database covering 30,000 mi2 and containing stratigraphic tops from ~90,000 wells; correlated 30 major stratigraphic horizons; digitized key wells, including wireline logs and sample logs; and analyzed more than 3,000 drill stem tests to establish that fluid levels in deep aquifers below the Permian evaporites are not connected to the surface and therefore pressures are not hydrostatic. Connectivity with the surface aquifers is lacking because shale aquitards and impermeable evaporite layers consist of both halite and anhydrite. 5. Developed extensive web applications and an interactive mapping system that do the following: a. Facilitate access to a wide array of data obtained in the study, including core descriptions and analyses, sample logs, digital (LAS) well logs, seismic data, gravity and magnetics maps, structural and stratigraphic maps, inferred fault traces, earthquakes, Class I and II disposal wells, and

  10. Modeling CO2 Sequestration in Saline Aquifer and Depleted Oil Reservoir To Evaluate Regional CO2 Sequestration Potential of Ozark Plateau Aquifer System, South-Central Kansas

    Energy Technology Data Exchange (ETDEWEB)

    Watney, W. Lynn [University Of Kansas Center For Research, Inc. Lawrence, KS (United States); Rush, Jason [University Of Kansas Center For Research, Inc. Lawrence, KS (United States); Raney, Jennifer [University Of Kansas Center For Research, Inc. Lawrence, KS (United States)

    2014-09-30

    1. Drilled, cored, and logged three wells to the basement and collecting more than 2,700 ft of conventional core; obtained 20 mi2 of multicomponent 3D seismic imaging and merged and reprocessed more than 125 mi2 of existing 3D seismic data for use in modeling CO2- EOR oil recovery and CO2 storage in five oil fields in southern Kansas. 2. Determined the technical feasibility of injecting and sequestering CO2 in a set of four depleted oil reservoirs in the Cutter, Pleasant Prairie South, Eubank, and Shuck fields in southwest Kansas; of concurrently recovering oil from those fields; and of quantifying the volumes of CO2 sequestered and oil recovered during the process. 3. Formed a consortium of six oil operating companies, five of which own and operate the four fields. The consortium became part of the Southwest Kansas CO2-EOR Initiative for the purpose of sharing data, knowledge, and interest in understanding the potential for CO2-EOR in Kansas. 4. Built a regional well database covering 30,000 mi2 and containing stratigraphic tops from ~90,000 wells; correlated 30 major stratigraphic horizons; digitized key wells, including wireline logs and sample logs; and analyzed more than 3,000 drill stem tests to establish that fluid levels in deep aquifers below the Permian evaporites are not connected to the surface and therefore pressures are not hydrostatic. Connectivity with the surface aquifers is lacking because shale aquitards and impermeable evaporite layers consist of both halite and anhydrite. 5. Developed extensive web applications and an interactive mapping system that do the following: a. Facilitate access to a wide array of data obtained in the study, including core descriptions and analyses, sample logs, digital (LAS) well logs, seismic data, gravity and magnetics maps, structural and stratigraphic maps, inferred fault traces, earthquakes, Class I and II disposal wells, and

  11. Enhancement of wadi recharge using dams coupled with aquifer storage and recovery wells

    KAUST Repository

    Missimer, Thomas M. M.

    2014-06-25

    Wadi channel recharge to the underlying alluvial aquifer is naturally limited by the flashy nature of flood events, evapotranspiration losses of water from the vadose zone, and aquifer heterogeneity, particularly low vertical hydraulic conductivity. Anthropogenic lowering of the water table in many wadi aquifers has also reduced the potential recharge by increasing the thickness of the vadose zone, causing interflow water loss from surface emergence and evaporation. A method to enhance recharge is to slow the flow within wadi channels by placement of dam structures, thereby ponding water and increasing the vertical head gradient to create a more rapid rate of infiltration and percolation. Effectiveness of wadi dams to enhance aquifer recharge reduces over time due to mud deposition within the reservoir caused by storm events. Up to 80 % of the water in old wadi reservoirs is lost to free-surface evaporation before infiltration and recharge can occur. One method to maintain or increase the rate of recharge is to convey clean water by gravity flow from the reservoir down-gradient to artificially recharge the aquifer using existing wells. This type of system is a low-cost and low-energy recharge method which could greatly enhance groundwater storage in wadi aquifers. Modeling results show that existing wells could store up to 1,000 m3/day under gravity-feed conditions and up to 3,900 m3/day with the shut-in of the well to produce a pressurized system. © 2014 Springer-Verlag Berlin Heidelberg.

  12. Two-phase flow visualization under reservoir conditions for highly heterogeneous conglomerate rock: A core-scale study for geologic carbon storage.

    Science.gov (United States)

    Kim, Kue-Young; Oh, Junho; Han, Weon Shik; Park, Kwon Gyu; Shinn, Young Jae; Park, Eungyu

    2018-03-20

    Geologic storage of carbon dioxide (CO 2 ) is considered a viable strategy for significantly reducing anthropogenic CO 2 emissions into the atmosphere; however, understanding the flow mechanisms in various geological formations is essential for safe storage using this technique. This study presents, for the first time, a two-phase (CO 2 and brine) flow visualization under reservoir conditions (10 MPa, 50 °C) for a highly heterogeneous conglomerate core obtained from a real CO 2 storage site. Rock heterogeneity and the porosity variation characteristics were evaluated using X-ray computed tomography (CT). Multiphase flow tests with an in-situ imaging technology revealed three distinct CO 2 saturation distributions (from homogeneous to non-uniform) dependent on compositional complexity. Dense discontinuity networks within clasts provided well-connected pathways for CO 2 flow, potentially helping to reduce overpressure. Two flow tests, one under capillary-dominated conditions and the other in a transition regime between the capillary and viscous limits, indicated that greater injection rates (potential causes of reservoir overpressure) could be significantly reduced without substantially altering the total stored CO 2 mass. Finally, the capillary storage capacity of the reservoir was calculated. Capacity ranged between 0.5 and 4.5%, depending on the initial CO 2 saturation.

  13. Sedimentology and reservoir heterogeneity of a valley-fill deposit-A field guide to the Dakota Sandstone of the San Rafael Swell, Utah

    Science.gov (United States)

    Kirschbaum, Mark A.; Schenk, Christopher J.

    2010-01-01

    Valley-fill deposits form a significant class of hydrocarbon reservoirs in many basins of the world. Maximizing recovery of fluids from these reservoirs requires an understanding of the scales of fluid-flow heterogeneity present within the valley-fill system. The Upper Cretaceous Dakota Sandstone in the San Rafael Swell, Utah contains well exposed, relatively accessible outcrops that allow a unique view of the external geometry and internal complexity of a set of rocks interpreted to be deposits of an incised valley fill. These units can be traced on outcrop for tens of miles, and individual sandstone bodies are exposed in three dimensions because of modern erosion in side canyons in a semiarid setting and by exhumation of the overlying, easily erodible Mancos Shale. The Dakota consists of two major units: (1) a lower amalgamated sandstone facies dominated by large-scale cross stratification with several individual sandstone bodies ranging in thickness from 8 to 28 feet, ranging in width from 115 to 150 feet, and having lengths as much as 5,000 feet, and (2) an upper facies composed of numerous mud-encased lenticular sandstones, dominated by ripple-scale lamination, in bedsets ranging in thickness from 5 to 12 feet. The lower facies is interpreted to be fluvial, probably of mainly braided stream origin that exhibits multiple incisions amalgamated into a complex sandstone body. The upper facies has lower energy, probably anastomosed channels encased within alluvial and coastal-plain floodplain sediments. The Dakota valley-fill complex has multiple scales of heterogeneity that could affect fluid flow in similar oil and gas subsurface reservoirs. The largest scale heterogeneity is at the formation level, where the valley-fill complex is sealed within overlying and underlying units. Within the valley-fill complex, there are heterogeneities between individual sandstone bodies, and at the smallest scale, internal heterogeneities within the bodies themselves. These

  14. Considering heterogeneities by transmissibilities averaging on adapted meshes in reservoir simulation; Prise en compte des heterogeneites par prise de moyenne des transmissivites sur maillages adaptes en simulation de reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Urgelli, D.

    1998-10-16

    Reservoir heterogeneity can be described using geostatistical models. But these models generate the heterogeneity on millions of fine grid blocks, which leads to prohibitive computational costs for reservoir simulations. In order to reduce the number of grid blocks, averaging techniques are needed to up-scale the fine scale permeabilities to the larger scales appropriate for flow simulation and engineering calculations. Grid block permeability up-scaling for numerical reservoir simulations has been discussed for a long time in the literature. It is now recognized that a full permeability tensor is needed to get an accurate reservoir description. But, the equivalent permeability on coarse grid blocks cannot be used directly on the numerical scheme. Usually, the harmonic average of the coarse grid block permeability is used for the transmissibility calculation, but it might cause a loss of accuracy. The purpose of this thesis is to present a new procedure for computing the equivalent transmissibility in the discretized flow equations on Cartesian grids and Corner Point Geometry grids. An application of this technique to a finite volume type numerical scheme is detailed. The principle of this technique is to calculate a permeability term on a shifted block placed between the two adjacent blocks where the transmissibility must be determined. At the field scale, the flow region can be divided into two types : a linear flow pattern with a low pressure gradient far from the wells and a radial flow pattern with a high pressure gradient in the vicinity of the wells. The radial flow region is usually more important for the prediction of production forecast, because it is directly related to the well. This was demonstrated theoretically and numerically for 2-D problem. The transmissibility up-scaling in radial flow pattern consists to determine the transmissibilities in the vicinity of wells and the numerical Productivity Index simultaneously. This new method called `shifted

  15. IDENTIFIABILITY VERSUS HETEROGENEITY IN GROUNDWATER MODELING SYSTEMS

    Directory of Open Access Journals (Sweden)

    A M BENALI

    2003-06-01

    Full Text Available Review of history matching of reservoirs parameters in groundwater flow raises the problem of identifiability of aquifer systems. Lack of identifiability means that there exists parameters to which the heads are insensitive. From the guidelines of the study of the homogeneous case, we inspect the identifiability of the distributed transmissivity field of heterogeneous groundwater aquifers. These are derived from multiple realizations of a random function Y = log T  whose probability distribution function is normal. We follow the identifiability of the autocorrelated block transmissivities through the measure of the sensitivity of the local derivatives DTh = (∂hi  ∕ ∂Tj computed for each sample of a population N (0; σY, αY. Results obtained from an analysis of Monte Carlo type suggest that the more a system is heterogeneous, the less it is identifiable.

  16. Heterogeneity-enhanced gas phase formation in shallow aquifers during leakage of CO2-saturated water from geologic sequestration sites

    DEFF Research Database (Denmark)

    Plampin, Michael R.; Lassen, Rune Nørbæk; Sakaki, Toshihiro

    2014-01-01

    A primary concern for geologic carbon storage is the potential for leakage of stored carbon dioxide (CO2) into the shallow subsurface where it could degrade the quality of groundwater and surface water. In order to predict and mitigate the potentially negative impacts of CO2 leakage, it is import......A primary concern for geologic carbon storage is the potential for leakage of stored carbon dioxide (CO2) into the shallow subsurface where it could degrade the quality of groundwater and surface water. In order to predict and mitigate the potentially negative impacts of CO2 leakage...... concentration in the flowing water, the distance between the heterogeneity and the leakage location, and some fundamental properties of the porous media. Results also show that interfaces where a less permeable material overlies a more permeable material affect gas phase evolution more significantly than...

  17. Heterogeneity of Sedimentary Aquifers: effect on microbial dynamics at successive spatial scales as revealed by geophysical imaging: Final report to the Department of Energy on Award DE-FG02-9ER62478

    Energy Technology Data Exchange (ETDEWEB)

    Donald J. P. Swift

    2004-02-10

    This report describes the geological component of the interdisciplinary study of the experimental aquifer at Oyster, Virginia, by the NABIR program, Department of Energy (Natural and Accelerated Bioremediation Research), between 1997 and 2003, as conducted by the Sediment dynamics group of Old Dominion University. The Geological component of the Oyster study was designed to (1) predict patterns of physical heterogeneity in sedimentary aquifers that control groundwater flow by application of geological first principles, (2) determine the geophysical imaging signatures of these patterns, and (3) relate patterns of physical heterogeneity thus sampled to observed microbial populations. The geological study began in 1997 at the North Oyster site, but in 2002, moved to the South Oyster site.

  18. CHROTRAN 1.0. A mathematical and computational model for in situ heavy metal remediation in heterogeneous aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Scott K.; Pandey, Sachin; Karra, Satish; Vesselinov, Velimir V. [Los Alamos National Laboratory, Los Alamos, NM (United States). Computational Earth Science Group (EES-16)

    2017-07-01

    Groundwater contamination by heavy metals is a critical environmental problem for which in situ remediation is frequently the only viable treatment option. For such interventions, a multi-dimensional reactive transport model of relevant biogeochemical processes is invaluable. To this end, we developed a model, chrotran, for in situ treatment, which includes full dynamics for five species: a heavy metal to be remediated, an electron donor, biomass, a nontoxic conservative bio-inhibitor, and a biocide. Direct abiotic reduction by donor-metal interaction as well as donor-driven biomass growth and bio-reduction are modeled, along with crucial processes such as donor sorption, bio-fouling, and biomass death. Our software implementation handles heterogeneous flow fields, as well as arbitrarily many chemical species and amendment injection points, and features full coupling between flow and reactive transport. We describe installation and usage and present two example simulations demonstrating its unique capabilities. One simulation suggests an unorthodox approach to remediation of Cr(VI) contamination.

  19. CHROTRAN 1.0: A mathematical and computational model for in situ heavy metal remediation in heterogeneous aquifers

    Science.gov (United States)

    Hansen, Scott K.; Pandey, Sachin; Karra, Satish; Vesselinov, Velimir V.

    2017-12-01

    Groundwater contamination by heavy metals is a critical environmental problem for which in situ remediation is frequently the only viable treatment option. For such interventions, a multi-dimensional reactive transport model of relevant biogeochemical processes is invaluable. To this end, we developed a model, text smallcaps">chrotran, for in situ treatment, which includes full dynamics for five species: a heavy metal to be remediated, an electron donor, biomass, a nontoxic conservative bio-inhibitor, and a biocide. Direct abiotic reduction by donor-metal interaction as well as donor-driven biomass growth and bio-reduction are modeled, along with crucial processes such as donor sorption, bio-fouling, and biomass death. Our software implementation handles heterogeneous flow fields, as well as arbitrarily many chemical species and amendment injection points, and features full coupling between flow and reactive transport. We describe installation and usage and present two example simulations demonstrating its unique capabilities. One simulation suggests an unorthodox approach to remediation of Cr(VI) contamination.

  20. Measurements of capillary pressure and electric permittivity of gas-water systems in porous media at elevated pressures : Application to geological storage of CO2 in aquifers and wetting behavior in coal

    NARCIS (Netherlands)

    Plug, W.J.

    2007-01-01

    Sequestration of CO2 in aquifers and coal layers is a promising technique to reduce greenhouse gas emissions. Considering the reservoir properties, e.g. wettability, heterogeneity and the caprocks sealing capacity, the capillary pressure is an important measure to evaluate the efficiency, the

  1. Transport of reservoir fines

    DEFF Research Database (Denmark)

    Yuan, Hao; Shapiro, Alexander; Stenby, Erling Halfdan

    Modeling transport of reservoir fines is of great importance for evaluating the damage of production wells and infectivity decline. The conventional methodology accounts for neither the formation heterogeneity around the wells nor the reservoir fines’ heterogeneity. We have developed an integral...

  2. Improved efficiency of miscible CO{sub 2} floods and enhanced prospects for CO{sub 2} flooding heterogeneous reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Grigg, Reid B.; Schechter, David S.; Chang, Shih-Hsien (Eric); Tsau, Jyun-Syung; Svec, Robert K.

    2000-02-04

    This project examines three major areas in which CO{sub 2} flooding can be improved: fluid and matrix interactions, conformance control, sweep efficiency, and reservoir simulation for improved oil recovery. This report discusses the activity during the calendar quarter covering October 1, 1999 through December 31, 1999 that covers mostly the second fiscal quarter of the project's third year. Injectivity experiments were performed on two Indian limestone cores. In tests on the first core, a variety of brine, CO{sub 2} WAG, and oil contaminant injection schemes indicated infectivity reduction due to phase conditions and contamination. The results are only quantitative because of plugging and erosion in the core. To date, tests on the second core have investigated the effects of long-term brine stability on the reduction of fluid-rock interaction, in order to quantify fluid effects on infectivity. The authors continue to develop a new approach in reservoir simulation to improve the history matching process on clusters of PCs. The main objective was to improve simulation of complex improved oil recovery methods, such as CO{sub 2}-foam for mobility control and sweep enhancements. Adsorption experiments using circulation and flow-through methods were used to determine the loss of surfactants for economic evaluation. A sacrificial agent, lignosulfonate, was used to reduce the adsorption of the primary foaming agent in both Berea sandstone and Indian limestone. The lignosulfonate has also shown a chromatograph effect, advancing more rapidly through the reservoir, thus initially adsorbing onto the rock before the primary foaming agent arrives. Therefore, considering the simplicity of operation and economics of reducing the cost of expensive surfactant to improve oil recovery, coinjection of lignosulfonate with the primary foaming agent might be a practical approach to consider for field application.

  3. Aquifer parameter identification and interpretation with different ...

    African Journals Online (AJOL)

    because within the aquifer test area there may appear heterogeneities and anisotropics which hinder the application of a single model. ... Abstract for&: aquifer parameter, [ransmissivity, storage coefficient, aquifer tests, analytical methods. Movement and ... since Cooper and Jacob (1946) proposed their simple and widely.

  4. Alluvial Aquifer

    Data.gov (United States)

    Kansas Data Access and Support Center — This coverage shows the extents of the alluvial aquifers in Kansas. The alluvial aquifers consist of unconsolidated Quaternary alluvium and contiguous terrace...

  5. Impacts of fluvial sedimentary heterogeneities on CO2 storage performance

    Science.gov (United States)

    Issautier, B. H.; Viseur, S.; Audigane, P. D.

    2011-12-01

    The heterogeneity of fluvial systems is a key parameter in sedimentology due to the associated impacts on flow performance. In a broader context, fluvial reservoirs are now targets for CO2 storage projects in several sedimentary basins (Paris Basin, North German Basin), thus calling for detailed characterization of reservoir behaviour and capacity. Fluvial reservoirs are a complex layout of highly heterogeneous sedimentary bodies with varying connectivity, depending on the sedimentary history of the system. Reservoir characterization must determine (a) the nature and dimension of the sedimentary bodies, and (b) the connectivity drivers and their evolution throughout the stratigraphic succession. Based on reservoir characterization, geological modelling must account for this information and can be used as a predictive tool for capacity estimation. Flow simulation, however, describes the reservoir behaviour with respect to CO2 injection. The present work focuses on fluvial reservoir performance and was carried out as part of a PhD (2008-2011) dedicated to the impact of sedimentary heterogeneity on CO2 storage performance. The work comprises three steps: ? Reservoir characterization based on detailed fieldwork (sedimentology and sequence stratigraphy) carried out in Central Arabia on the Minjur Sandstone. Twelve depositional environments and their associated heterogeneity are identified, and their layout is presented in a high-resolution sequence stratigraphy analysis. This step is summed up in a 3D geological model. ? Conceptual modelling based on this field data, using gOcad software and an in-house python code. The purpose was to study, for a given architecture, the impact of sedimentary heterogeneity on storage capacity estimations using two models: one with heterogeneity within the sedimentary fill (model A); the other without heterogeneity within the sedimentary fill (model B). A workflow was designed to estimate and compare the storage capacities for a series

  6. Role of physical heterogeneity in the interpretation of small-scale laboratory and field observations of bacteria, microbial-sized microsphere, and bromide transport through aquifer sediments

    Science.gov (United States)

    Harvey, Ronald W.; Kinner, Nancy E.; MacDonald, Dan; Metge, David W.; Bunn, Amoret

    1993-01-01

    The effect of physical variability upon the relative transport behavior of microbial-sized microspheres, indigenous bacteria, and bromide was examined in field and flow-through column studies for a layered, but relatively well sorted, sandy glaciofluvial aquifer. These investigations involved repacked, sieved, and undisturbed aquifer sediments. In the field, peak abundance of labeled bacteria traveling laterally with groundwater flow 6 m downgradient from point of injection was coincident with the retarded peak of carboxylated microspheres (retardation factor, RF = 1.7) at the 8.8 m depth, but preceded the bromide peak and the retarded microsphere peak (RF = 1.5) at the 9.0 m depth. At the 9.5 m depth, the bacterial peak was coincident with both the bromide and the microsphere peaks. Although sorption appeared to be a predominant mechanism responsible for immobilization of microbial-sized microspheres in the aquifer, straining appeared to be primarily responsible for their removal in 0.6-m-long columns of repacked, unsieved aquifer sediments. The manner in which the columns were packed also affected optimal size for microsphere transport, which in one experiment was near the size of the small (∼2 μm) groundwater protozoa (flagellates). These data suggest that variability in aquifer sediment structure can be important in interpretation of both small-scale field and laboratory experiments examining microbial transport behavior.

  7. Inversion of multicomponent seismic data and rock-physics intepretation for evaluating lithology, fracture and fluid distribution in heterogeneous anisotropic reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Ilya Tsvankin; Kenneth L. Larner

    2004-11-17

    Within the framework of this collaborative project with the Lawrence Livermore National Laboratory (LLNL) and Stanford University, the Colorado School of Mines (CSM) group developed and implemented a new efficient approach to the inversion and processing of multicomponent, multiazimuth seismic data in anisotropic media. To avoid serious difficulties in the processing of mode-converted (PS) waves, we devised a methodology for transforming recorded PP- and PS-wavefields into the corresponding SS-wave reflection data that can be processed by velocity-analysis algorithms designed for pure (unconverted) modes. It should be emphasized that this procedure does not require knowledge of the velocity model and can be applied to data from arbitrarily anisotropic, heterogeneous media. The azimuthally varying reflection moveouts of the PP-waves and constructed SS-waves are then combined in anisotropic stacking-velocity tomography to estimate the velocity field in the depth domain. As illustrated by the case studies discussed in the report, migration of the multicomponent data with the obtained anisotropic velocity model yields a crisp image of the reservoir that is vastly superior to that produced by conventional methods. The scope of this research essentially amounts to building the foundation of 3D multicomponent, anisotropic seismology. We have also worked with the LLNL and Stanford groups on relating the anisotropic parameters obtained from seismic data to stress, lithology, and fluid distribution using a generalized theoretical treatment of fractured, poroelastic rocks.

  8. Hydrodynamic characterization of the Paleocene aquifer in the ...

    African Journals Online (AJOL)

    The intense exploitation of shallow aquifers in the coastal basin of Togo provokes a rapid depletion of these reservoirs. The confined paleocene aquifer represents potential reserves that are yet little exploited. This paper presents the hydrodynamic characterization of this aquifer. Piezometric data established from 80 wells ...

  9. A look deep inside the a hillslope reveals a structured heterogeneity of isotopic reservoirs and distinct water use strategies for adjacent trees

    Science.gov (United States)

    Oshun, J.; Rempe, D. M.; Link, P.; Simonin, K. A.; Dietrich, W.; Dawson, T. E.; Fung, I.

    2012-12-01

    Whereas recent studies have begun to note the importance of weathered rock as a source of moisture for vegetation and, through transpiration, as a moderator of local and regional climate, no study has looked deeply into a hillslope in three-dimensions to explore dynamics in the hydrologic cycle and tree water use. Here, we use natural abundance stable isotope techniques to reveal distinct isotopic reservoirs within the hillslope, as well as quantify the movement of water from weathered rock and soil into vegetation. Our study site, at the Angelo Coast Range Reserve in Northern California, is a 4000 m2 unchanneled catchment that drains into Elder Creek, in the South Fork of the Eel River basin. Although average annual rainfall is 1900mm, 90% falls between October and May, forcing vegetation to find deep sources of moisture to survive the dry summer. An old-growth mixed conifer forest with trees as tall as 65 m grows on a 38° slope, with soils 10-60 cm thick underlain by vertically dipping, weathered turbidite sequences of the Coastal Franciscan Belt. A perched seasonally drains to unweathered bedrock. The water table fluctuates between 3 and 5 m below the surface near Elder Creek, and between 18 and 24 m below the surface at the hillslope divide. The site contains over 850 sensors monitoring the climatic variables and the movement of water through the subsurface, vegetation and into the atmosphere. Daily rainwater sampling during storm events from 2007-2012 shows a Local Meteoric Water Line, setting the context for our comparison of isotopic reservoirs. From Summer 2011 to Fall 2012, bi-weekly to tri-weekly samples were collected of tree xylem of over 30 individuals of Pseudotsuga menziesii, quercus agrifolia, arbutus menziesii, Umbellularia californica, Notholithocarpus densiflorus, acer macrophyllum, as well as from soil and rock to a depth of 1-1.3 m, and from the water table at 12 wells across the hillslope. Analysis reveals a structured heterogeneity of

  10. Reservoir simulation with imposed flux continuity conditions on heterogeneous and anisotropic media for general geometries, and the inclusion of hysteresis in forward modeling

    Energy Technology Data Exchange (ETDEWEB)

    Eigestad, Geir Terje

    2003-04-01

    The thesis is divided into two main parts. Part I gives an overview and summary of the theory that lies behind the flow equations and the discretization principles used in the work. Part II is a collection of research papers that have been written by the candidate (in collaboration with others). The main objective of this thesis is the discretization of an elliptic PDE which describes the pressure in a porous medium. The porous medium will in general be described by permeability tensors which are heterogeneous and anisotropic. In addition, the geometry is often complex for practical applications. This requires discretization approaches that are suited for the problems in mind. The discretization approaches used here are based on imposed flux and potential continuity, and will be discussed in detail in Chapter 3 of Part I. These methods are called Multi Point Flux Approximation Methods, and the acronym MPFA will be used for them. Issues related to these methods will be the main issue of this thesis. The rest of this thesis is organised as follows: Part I: Chapter 1 gives a brief overview of the physics and mathematics behind reservoir simulation. The standard mass balance equations are presented, and we try to explain what reservoir simulation is. Some standard discretization s methods are briefly discussed in Chapter 2. The main focus in Part I is on the MPFA discretization approach for various geometries, and is given in Chapter 3. Some details may have been left out in the papers of Part II, and the section serves both as a summary of the discretization method(s), as well as a more detailed description than what is found in the papers. In Chapter 4, extensions to handle time dependent and nonlinear problems are discussed. Some of the numerical examples presented in Part II deal with two phase flow, and are based on the extension given in this chapter. Chapter 5 discusses numerical results that have been obtained for the MPFA methods for elliptic problems, and

  11. Dynamic pore network model of surface heterogeneity in brine-filled porous media for carbon sequestration.

    Science.gov (United States)

    Ellis, Jonathan S; Bazylak, Aimy

    2012-06-21

    Trapping of carbon in deep underground brine-filled reservoirs is a promising approach for the reduction of atmospheric greenhouse gas emissions. However, estimation of the amount of carbon dioxide (CO(2)) that can be captured in a given reservoir and the long-term storage stability remain a challenge. One difficulty lies in the estimation of local capillary pressure effects that arise from mineral surface heterogeneity inherent in underground geological formations. As a preliminary step to address this issue, we have performed dynamic pore network modelling (PNM) simulations of two-phase immiscible flow in two-dimensional structured porous media with contact angle heterogeneity under typical reservoir conditions. We begin by characterizing the network with a single, uniform contact angle. We then present saturation patterns for networks with homogeneous and heterogeneous contact angles distributions, based on two common reservoir minerals: quartz and mica, both of which have been well-characterized experimentally for their brine-CO(2) contact angles. At lower flow rates, we found moderately higher saturations for the heterogeneous networks than for the homogeneous ones. To characterize the fingering patterns, we have introduced R as the ratio of filled throats to the total network saturation. Based on this measure, the heterogeneous networks demonstrated thicker fingering patterns than the homogeneous networks. The computed saturation patterns demonstrate the importance of considering surface heterogeneity in pore-scale modelling of deep saline aquifers.

  12. Integrating borehole logs and aquifer tests in aquifer characterization

    Science.gov (United States)

    Paillet, Frederick L.; Reese, R.S.

    2000-01-01

    Integration of lithologic logs, geophysical logs, and hydraulic tests is critical in characterizing heterogeneous aquifers. Typically only a limited number of aquifer tests can be performed, and these need to be designed to provide hydraulic properties for the principle aquifers in the system. This study describes the integration of logs and aquifer tests in the development of a hydrostratigraphic model for the surficial aquifer system in and around Big Cypress National Preserve in eastern Collier County, Florida. Borehole flowmeter tests provide qualitative permeability profiles in most of 26 boreholes drilled in the Study area. Flow logs indicate the depth of transmissive units, which are correlated across the study area. Comparison to published studies in adjacent areas indicates that the main limestone aquifer of the 000000Tamiami Formation in the study area corresponds with the gray limestone aquifer in western Dade County and the water table and lower Tamiami Aquifer in western Collier County. Four strategically located, multiwell aquifer tests are used to quantify the qualitative permeability profiles provided by the flowmeter log analysis. The hydrostratigraphic model based on these results defines the main aquifer in the central part of the study area as unconfined to semiconfined with a transmissivity as high as 30,000 m2/day. The aquifer decreases in transmissivity to less than 10,000 m2/day in some parts of western Collier County, and becomes confined to the east and northeast of the study area, where transmissivity decreases to below 5000 m2/day.Integration of lithologic logs, geophysical logs, and hydraulic tests is critical in characterizing heterogeneous aquifers. Typically only a limited number of aquifer tests can be performed, and these need to be designed to provide hydraulic properties for the principle aquifers in the system. This study describes the integration of logs and aquifer tests in the development of a hydrostratigraphic model for the

  13. The fate of pesticides in soil and aquifers from a small-scale point of view: Does microbial and spatial heterogeneity have an impact?

    DEFF Research Database (Denmark)

    Aamand, J.; Badawi, N.; Rosenbom, Annette Elisabeth

    of mineralisation potentials was observed with fewer samples showing rapid mineralisation and more samples showing either slow 0-order mineralisation kinetics or no degradation. A heterogeneous distribution of herbicide mineralisation potentials was also observed in the groundwater sediment showing the most rapid...... mineralization close to the water table. The impacts of microbial heterogeneity on degradation and leaching of MCPA through the upper meter of subsurface sediment is evaluated with a numerical model. Results show that for reasonably uniform soils, heterogeneity in mineralisation has little effect on leached...

  14. Impact of climate change on freshwater resources in a heterogeneous coastal aquifer of Bremerhaven, Germany: A three-dimensional modeling study

    Science.gov (United States)

    Yang, Jie; Graf, Thomas; Ptak, Thomas

    2015-06-01

    Climate change is expected to induce sea level rise in the German Bight, which is part of the North Sea, Germany. Climate change may also modify river discharge of the river Weser flowing into the German Bight, which will alter both pressure and salinity distributions in the river Weser estuary. To study the long-term interaction between sea level rise, discharge variations, a storm surge and coastal aquifer flow dynamics, a 3D seawater intrusion model was designed using the fully coupled surface-subsurface numerical model HydroGeoSphere. The model simulates the coastal aquifer as an integral system considering complexities such as variable-density flow, variably saturated flow, irregular boundary conditions, irregular land surface and anthropogenic structures (e.g., dyke, drainage canals, water gates). The simulated steady-state groundwater flow of the year 2009 is calibrated using PEST. In addition, four climate change scenarios are simulated based on the calibrated model: (i) sea level rise of 1 m, (ii) the salinity of the seaside boundary increases by 4 PSU (Practical Salinity Units), (iii) the salinity of the seaside boundary decreases by 12 PSU, and (iv) a storm surge with partial dyke failure. Under scenarios (i) and (iv), the salinized area expands several kilometers further inland during several years. Natural remediation can take up to 20 years. However, sudden short-term salinity changes in the river Weser estuary do not influence the salinized area in the coastal aquifer. The obtained results are useful for coastal engineering practices and drinking water resource management.

  15. Prototyping and Testing a New Volumetric Curvature Tool for Modeling Reservoir Compartments and Leakage Pathways in the Arbuckle Saline Aquifer: Reducing Uncertainty in CO2 Storage and Permanence

    Energy Technology Data Exchange (ETDEWEB)

    Rush, Jason [Univ. of Kansas and Kansas Geological Survey, Lawrence, KS (United States); Holubnyak, Yevhen [Univ. of Kansas and Kansas Geological Survey, Lawrence, KS (United States); Watney, Willard [Univ. of Kansas and Kansas Geological Survey, Lawrence, KS (United States)

    2016-12-09

    This DOE-funded project evaluates the utility of seismic volumetric curvature (VC) for predicting stratal and structural architecture diagnostic of paleokarst reservoirs. Of special interest are applications geared toward carbon capture, utilization, and storage (CCUS). VC has been championed for identifying faults (offset <¼ λ) that cannot be imaged by conventional 3-D seismic attributes such as coherence. The objective of this research was to evaluate VC-techniques for reducing uncertainties in reservoir compartmentalization studies and seal risk assessments especially for saline aquifers. A 2000-ft horizontal lateral was purposefully drilled across VC-imaged lineaments—interpreted to record a fractured and a fault-bounded doline—to physically confirm their presence. The 15-mi² study area is located in southeastern Bemis-Shutts Field, which is situated along the crest of the Central Kansas Uplift (CKU) in Ellis County, Kansas. The uppermost Arbuckle (200+ ft) has extensive paleokarst including collapsed paleocaverns and dolines related to exceedingly prolonged pre-Simpson (Sauk–Tippecanoe) and/or pre-Pennsylvanian subaerial exposure. A lateral borehole was successfully drilled across the full extent (~1100 ft) of a VC-inferred paleokarst doline. Triple combo (GR-neutron/density-resistivity), full-wave sonic, and borehole micro-imager logs were successfully run to TD on drill-pipe. Results from the formation evaluation reveal breccias (e.g., crackle, mosaic, chaotic), fractures, faults, vugs (1-6"), and unaffected host strata consistent with the pre-spud interpretation. Well-rounded pebbles were also observed on the image log. VC-inferred lineaments coincide with 20–80-ft wide intervals of high GR values (100+ API), matrix-rich breccias, and faults. To further demonstrate their utility, VC attributes are integrated into a geocellular modeling workflow: 1) to constrain the structural model; 2) to generate facies probability grids, and; 3) to collocate

  16. Heterogeneous redox conditions, arsenic mobility, and groundwater flow in a fractured-rock aquifer near a waste repository site in New Hampshire, USA

    Science.gov (United States)

    Harte, Philip T.; Ayotte, Joseph D.; Hoffman, Andrew; Revesz, Kinga M.; Belaval, Marcel; Lamb, Steven; Böhlke, J.K.

    2012-01-01

    Anthropogenic sources of carbon from landfill or waste leachate can promote reductive dissolution of in situ arsenic (As) and enhance the mobility of As in groundwater. Groundwater from residential-supply wells in a fractured crystalline-rock aquifer adjacent to a Superfund site in Raymond, New Hampshire, USA, showed evidence of locally enhanced As mobilization in relatively reducing (mixed oxic-anoxic to anoxic) conditions as determined by redox classification and other lines of evidence. Redox classification was determined from geochemical indicators based on threshold concentrations of dissolved oxygen (DO), nitrate (NO3-), iron (Fe2+), manganese (Mn2+), and sulfate (SO42-). Redox conditions were evaluated also based on methane (CH4), excess nitrogen gas (N2) from denitrification, the oxidation state of dissolved As speciation (As(III) and As(V)), and several stable isotope ratios. Samples from the residential-supply wells primarily exhibit mixed redox conditions, as most have long open boreholes (typically 50–100 m) that receive water from multiple discrete fractures with contrasting groundwater chemistry and redox conditions. The methods employed in this study can be used at other sites to gauge redox conditions and the potential for As mobilization in complex fractured crystalline-rock aquifers where multiple lines of evidence are likely needed to understand As occurrence, mobility, and transport.

  17. Inversion of a dual-continuum approach to flow in a karstified limestone: Insight into aquifer heterogeneity revealed by well-test interferences

    Science.gov (United States)

    Trottier, Nicolas; Delay, Frederick; Bildstein, Olivier; Ackerer, Philippe

    2014-01-01

    Inverting flow in a dual continuum results in mildly heterogeneous parameters.Hydrodynamic parameters of a dual continuum lack of spatial correlation.Parameter statistical distributions are not widened by occurrence of karstic flow.Interference testing is weakly sensitive to matrix parameters of a dual continuum.

  18. Application of Integrated Reservoir Management and Reservoir Characterization to Optimize Infill Drilling

    Energy Technology Data Exchange (ETDEWEB)

    None

    1998-01-01

    Infill drilling if wells on a uniform spacing without regard to reservoir performance and characterization foes not optimize reservoir development because it fails to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, and carbonate reservoirs in particular. New and emerging technologies, such as geostatistical modeling, rigorous decline curve analysis, reservoir rock typing, and special core analysis can be used to develop a 3-D simulation model for prediction of infill locations.

  19. Solid-phase arsenic speciation in aquifer sediments: A micro-X-ray absorption spectroscopy approach for quantifying trace-level speciation

    Science.gov (United States)

    Nicholas, Sarah L.; Erickson, Melinda L.; Woodruff, Laurel G.; Knaeble, Alan R.; Marcus, Matthew A.; Lynch, Joshua K.; Toner, Brandy M.

    2017-08-01

    Arsenic (As) is a geogenic contaminant affecting groundwater in geologically diverse systems globally. Arsenic release from aquifer sediments to groundwater is favored when biogeochemical conditions, especially oxidation-reduction (redox) potential, in aquifers fluctuate. The specific objective of this research is to identify the solid-phase sources and geochemical mechanisms of release of As in aquifers of the Des Moines Lobe glacial advance. The overarching concept is that conditions present at the aquifer-aquitard interfaces promote a suite of geochemical reactions leading to mineral alteration and release of As to groundwater. A microprobe X-ray absorption spectroscopy (μXAS) approach is developed and applied to rotosonic drill core samples to identify the solid-phase speciation of As in aquifer, aquitard, and aquifer-aquitard interface sediments. This approach addresses the low solid-phase As concentrations, as well as the fine-scale physical and chemical heterogeneity of the sediments. The spectroscopy data are analyzed using novel cosine-distance and correlation-distance hierarchical clustering for Fe 1s and As 1s μXAS datasets. The solid-phase Fe and As speciation is then interpreted using sediment and well-water chemical data to propose solid-phase As reservoirs and release mechanisms. The results confirm that in two of the three locations studied, the glacial sediment forming the aquitard is the source of As to the aquifer sediments. The results are consistent with three different As release mechanisms: (1) desorption from Fe (oxyhydr)oxides, (2) reductive dissolution of Fe (oxyhydr)oxides, and (3) oxidative dissolution of Fe sulfides. The findings confirm that glacial sediments at the interface between aquifer and aquitard are geochemically active zones for As. The diversity of As release mechanisms is consistent with the geographic heterogeneity observed in the distribution of elevated-As wells.

  20. Guarani aquifer

    International Nuclear Information System (INIS)

    2007-01-01

    The environmental protection and sustain ability develop project of Guarani Aquifer System is a join work from Argentina, Brazil, Paraguay and Uruguay with a purpose to increase the knowledge resource and propose technical legal and organizational framework for sustainable management between countries.The Universities funds were created as regional universities support in promotion, training and academic research activities related to environmental al social aspects of the Guarani Aquifer System.The aim of the project is the management and protection of the underground waters resources taking advantage and assesment for nowadays and future generations

  1. Geothermal reservoir management

    Energy Technology Data Exchange (ETDEWEB)

    Scherer, C.R.; Golabi, K.

    1978-02-01

    The optimal management of a hot water geothermal reservoir was considered. The physical system investigated includes a three-dimensional aquifer from which hot water is pumped and circulated through a heat exchanger. Heat removed from the geothermal fluid is transferred to a building complex or other facility for space heating. After passing through the heat exchanger, the (now cooled) geothermal fluid is reinjected into the aquifer. This cools the reservoir at a rate predicted by an expression relating pumping rate, time, and production hole temperature. The economic model proposed in the study maximizes discounted value of energy transferred across the heat exchanger minus the discounted cost of wells, equipment, and pumping energy. The real value of energy is assumed to increase at r percent per year. A major decision variable is the production or pumping rate (which is constant over the project life). Other decision variables in this optimization are production timing, reinjection temperature, and the economic life of the reservoir at the selected pumping rate. Results show that waiting time to production and production life increases as r increases and decreases as the discount rate increases. Production rate decreases as r increases and increases as the discount rate increases. The optimal injection temperature is very close to the temperature of the steam produced on the other side of the heat exchanger, and is virtually independent of r and the discount rate. Sensitivity of the decision variables to geohydrological parameters was also investigated. Initial aquifer temperature and permeability have a major influence on these variables, although aquifer porosity is of less importance. A penalty was considered for production delay after the lease is granted.

  2. Full-waveform inversion of cross-hole GPR data collected in a strongly heterogeneous chalk reservoir analogue with sharp permittivity and conductivity contrasts

    DEFF Research Database (Denmark)

    Keskinen, Johanna; Zibar, Majken Caroline Looms; Moreau, Julien

    2014-01-01

    Chalk sediments form an important reservoir for groundwater onshore and for hydrocarbons in the Danish sector of the North Sea. Cross-hole Ground-penetrating radar (GPR) tomography is an efficient method to investigate subtle porosity variations in the chalk. Traditional ray-based inversion...

  3. Spatial distribution of the .i.Daphnia longispina./i. species complex and other planktonic crustaceans in the heterogeneous environment of canyon-shaped reservoirs

    Czech Academy of Sciences Publication Activity Database

    Seďa, Jaromír; Petrusek, A.; Macháček, Jiří; Šmilauer, P.

    2007-01-01

    Roč. 29, č. 7 (2007), s. 619-628 ISSN 0142-7873 R&D Projects: GA ČR(CZ) GA206/04/0190 Institutional research plan: CEZ:AV0Z60170517 Keywords : Daphnia longispina species complex * canyon-shaped reservoirs Subject RIV: DA - Hydrology ; Limnology Impact factor: 1.897, year: 2007

  4. Comment on "Advective transport in heterogeneous aquifers: Are proxy models predictive?" by A. Fiori, A. Zarlenga, H. Gotovac, I. Jankovic, E. Volpi, V. Cvetkovic, and G. Dagan

    Science.gov (United States)

    Neuman, Shlomo P.

    2016-07-01

    Fiori et al. (2015) examine the predictive capabilities of (among others) two "proxy" non-Fickian transport models, MRMT (Multi-Rate Mass Transfer) and CTRW (Continuous-Time Random Walk). In particular, they compare proxy model predictions of mean breakthrough curves (BTCs) at a sequence of control planes with near-ergodic BTCs generated through two- and three-dimensional simulations of nonreactive, mean-uniform advective transport in single realizations of stationary, randomly heterogeneous porous media. The authors find fitted proxy model parameters to be nonunique and devoid of clear physical meaning. This notwithstanding, they conclude optimistically that "i. Fitting the proxy models to match the BTC at [one control plane] automatically ensures prediction at downstream control planes [and thus] ii. … the measured BTC can be used directly for prediction, with no need to use models underlain by fitting." I show that (a) the authors' findings follow directly from (and thus confirm) theoretical considerations discussed earlier by Neuman and Tartakovsky (2009), which (b) additionally demonstrate that proxy models will lack similar predictive capabilities under more realistic, non-Markovian flow and transport conditions that prevail under flow through nonstationary (e.g., multiscale) media in the presence of boundaries and/or nonuniformly distributed sources, and/or when flow/transport are conditioned on measurements.

  5. An Integrated Approach Based on Numerical Modelling and Geophysical Survey to Map Groundwater Salinity in Fractured Coastal Aquifers

    Directory of Open Access Journals (Sweden)

    Costantino Masciopinto

    2017-11-01

    Full Text Available Aquifer over-exploitation may increase coastal seawater intrusion by reducing freshwater availability. Fractured subsurface formations commonly host important freshwater reservoirs along sea coasts. These water resources are particularly vulnerable to the contamination due to seawater infiltration occurring through rapid pathways via fractures. Modeling of density driven fluid flow in fractured aquifers is complex, as their hydrodynamics are controlled by interactions between preferential flow pathways, 3D interconnected fractures and rock-matrix porosity distribution. Moreover, physical heterogeneities produce highly localized water infiltrations that make the modeling of saltwater transport in such aquifers very challenging. The new approach described in this work provides a reliable hydrogeological model suitable to reproduce local advancements of the freshwater/saltwater wedge in coastal aquifers. The proposed model use flow simulation results to estimate water salinities in groundwater at a specific depth (1 m below water table by means of positions of the Ghyben-Herzberg saltwater/freshwater sharp interface along the coast. Measurements of salinity in 25 boreholes (i.e., salinity profiles have been used for the model calibration. The results provide the groundwater salinity map in freshwater/saltwater transition coastal zones of the Bari (Southern Italy fractured aquifer. Non-invasive geophysical measurements in groundwater, particularly into vertical 2D vertical cross-sections, were carried out by using the electrical resistivity tomography (ERT in order to validate the model results. The presented integrated approach is very easy to apply and gives very realistic salinity maps in heterogeneous aquifers, without simulating density driven water flow in fractures.

  6. Application of Integrated Reservoir Management and Reservoir Characterization to Optimize Infill Drilling

    Energy Technology Data Exchange (ETDEWEB)

    P. K. Pande

    1998-10-29

    Initial drilling of wells on a uniform spacing, without regard to reservoir performance and characterization, must become a process of the past. Such efforts do not optimize reservoir development as they fail to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, and carbonate reservoirs in particular. These reservoirs are typically characterized by: o Large, discontinuous pay intervals o Vertical and lateral changes in reservoir properties o Low reservoir energy o High residual oil saturation o Low recovery efficiency

  7. Simulation of CO2 Sequestration at Rock Spring Uplift, Wyoming: Heterogeneity and Uncertainties in Storage Capacity, Injectivity and Leakage

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Hailin [Los Alamos National Laboratory; Dai, Zhenxue [Los Alamos National Laboratory; Jiao, Zunsheng [Wyoming State Geological Survey; Stauffer, Philip H. [Los Alamos National Laboratory; Surdam, Ronald C. [Wyoming State Geological Survey

    2011-01-01

    Many geological, geochemical, geomechanical and hydrogeological factors control CO{sub 2} storage in subsurface. Among them heterogeneity in saline aquifer can seriously influence design of injection wells, CO{sub 2} injection rate, CO{sub 2} plume migration, storage capacity, and potential leakage and risk assessment. This study applies indicator geostatistics, transition probability and Markov chain model at the Rock Springs Uplift, Wyoming generating facies-based heterogeneous fields for porosity and permeability in target saline aquifer (Pennsylvanian Weber sandstone) and surrounding rocks (Phosphoria, Madison and cap-rock Chugwater). A multiphase flow simulator FEHM is then used to model injection of CO{sub 2} into the target saline aquifer involving field-scale heterogeneity. The results reveal that (1) CO{sub 2} injection rates in different injection wells significantly change with local permeability distributions; (2) brine production rates in different pumping wells are also significantly impacted by the spatial heterogeneity in permeability; (3) liquid pressure evolution during and after CO{sub 2} injection in saline aquifer varies greatly for different realizations of random permeability fields, and this has potential important effects on hydraulic fracturing of the reservoir rock, reactivation of pre-existing faults and the integrity of the cap-rock; (4) CO{sub 2} storage capacity estimate for Rock Springs Uplift is 6614 {+-} 256 Mt at 95% confidence interval, which is about 36% of previous estimate based on homogeneous and isotropic storage formation; (5) density profiles show that the density of injected CO{sub 2} below 3 km is close to that of the ambient brine with given geothermal gradient and brine concentration, which indicates CO{sub 2} plume can sink to the deep before reaching thermal equilibrium with brine. Finally, we present uncertainty analysis of CO{sub 2} leakage into overlying formations due to heterogeneity in both the target saline

  8. Seismic reflection and structuring characterization of deep aquifer system in the Dakhla syncline (Cap Bon, North-Eastern Tunisia)

    Science.gov (United States)

    Bellali, Abir; Jarraya Horriche, Faten; Gabtni, Hakim; Bédir, Mourad

    2018-04-01

    The Dakhla syncline is located in the North-Eastern Tunisia. It is bounded by Abd El Rahmene anticline to the North-West, El Haouaria Graben to the North-East, Grombalia Graben to the South-West and the Mediterranean Sea to the East. The main aquifer reservoirs of Dakhla syncline are constituted by stacks of fluvial to deltaic Neogene sequences and carbonates. The interpretation of eight seismic reflection profiles, calibrated by wire line logging data of three oil wells, hydraulic wells and geologic field sections highlighted the impact of tectonics on the structuring geometry of aquifers and their distribution in elevated structures and subsurface depressions. Lithostratigraphic correlations and seismic profiles analysis through the syncline show that the principal aquifers are thickest within the central and northern part of the study area and thinnest to the southern part of the syncline. Seismic sections shows that the fracture/fault pattern in this syncline is mainly concentrated along corridors with a major direction of NW-SE and secondary directions of N-S, E-W and NE-SW with different release. This is proved by the complexity structure of Eastern Tunisia, resulted from the interaction between the African and Eurasiatic plates. Isochron maps of aquifers systems exhibited the structuring of this syncline in sub-surface characterized by important lateral and vertical geometric and thickness variations. Seismic sections L1, L2, L3, L4, L5 and petroleum wells showed an heterogeneous multilayer aquifers of Miocene formed by the arrangement of ten sandstone bodies, separated by impermeable clay packages. Oligo-Miocene deposits correspond to the most great potential aquifers, with respectively an average transmissivity estimated: Somaa aquifer 6.5 10-4 m2/s, Sandstone level aquifer 2.6 10-3 m2/s, Beglia aquifer 1.1 10-3 m2/s, Ain Ghrab aquifer 1.3 10-4 m2/s and Oligocene aquifer 2 10-3 m2/s. The interpretation of spatial variations of seismic units and the

  9. APPLICATION OF INTEGRATED RESERVOIR MANAGEMENT AND RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Jack Bergeron; Tom Blasingame; Louis Doublet; Mohan Kelkar; George Freeman; Jeff Callard; David Moore; David Davies; Richard Vessell; Brian Pregger; Bill Dixon; Bryce Bezant

    2000-03-01

    Reservoir performance and characterization are vital parameters during the development phase of a project. Infill drilling of wells on a uniform spacing, without regard to characterization does not optimize development because it fails to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, especially carbonate reservoirs. These reservoirs are typically characterized by: (1) large, discontinuous pay intervals; (2) vertical and lateral changes in reservoir properties; (3) low reservoir energy; (4) high residual oil saturation; and (5) low recovery efficiency. The operational problems they encounter in these types of reservoirs include: (1) poor or inadequate completions and stimulations; (2) early water breakthrough; (3) poor reservoir sweep efficiency in contacting oil throughout the reservoir as well as in the nearby well regions; (4) channeling of injected fluids due to preferential fracturing caused by excessive injection rates; and (5) limited data availability and poor data quality. Infill drilling operations only need target areas of the reservoir which will be economically successful. If the most productive areas of a reservoir can be accurately identified by combining the results of geological, petrophysical, reservoir performance, and pressure transient analyses, then this ''integrated'' approach can be used to optimize reservoir performance during secondary and tertiary recovery operations without resorting to ''blanket'' infill drilling methods. New and emerging technologies such as geostatistical modeling, rock typing, and rigorous decline type curve analysis can be used to quantify reservoir quality and the degree of interwell communication. These results can then be used to develop a 3-D simulation model for prediction of infill locations. The application of reservoir surveillance techniques to identify additional reservoir ''pay'' zones

  10. Stochastic analysis of virus transport in aquifers

    Science.gov (United States)

    Campbell Rehmann, Linda L.; Welty, Claire; Harvey, Ronald W.

    1999-01-01

    A large-scale model of virus transport in aquifers is derived using spectral perturbation analysis. The effects of spatial variability in aquifer hydraulic conductivity and virus transport (attachment, detachment, and inactivation) parameters on large-scale virus transport are evaluated. A stochastic mean model of virus transport is developed by linking a simple system of local-scale free-virus transport and attached-virus conservation equations from the current literature with a random-field representation of aquifer and virus transport properties. The resultant mean equations for free and attached viruses are found to differ considerably from the local-scale equations on which they are based and include effects such as a free-virus effective velocity that is a function of aquifer heterogeneity as well as virus transport parameters. Stochastic mean free-virus breakthrough curves are compared with local model output in order to observe the effects of spatial variability on mean one-dimensional virus transport in three-dimensionally heterogeneous porous media. Significant findings from this theoretical analysis include the following: (1) Stochastic model breakthrough occurs earlier than local model breakthrough, and this effect is most pronounced for the least conductive aquifers studied. (2) A high degree of aquifer heterogeneity can lead to virus breakthrough actually preceding that of a conservative tracer. (3) As the mean hydraulic conductivity is increased, the mean model shows less sensitivity to the variance of the natural-logarithm hydraulic conductivity and mean virus diameter. (4) Incorporation of a heterogeneous colloid filtration term results in higher predicted concentrations than a simple first-order adsorption term for a given mean attachment rate. (5) Incorporation of aquifer heterogeneity leads to a greater range of virus diameters for which significant breakthrough occurs. (6) The mean model is more sensitive to the inactivation rate of viruses

  11. Simulation of the mulltizones clastic reservoir: A case study of Upper Qishn Clastic Member, Masila Basin-Yemen

    Science.gov (United States)

    Khamis, Mohamed; Marta, Ebrahim Bin; Al Natifi, Ali; Fattah, Khaled Abdel; Lashin, Aref

    2017-06-01

    The Upper Qishn Clastic Member is one of the main oil-bearing reservoirs that are located at Masila Basin-Yemen. It produces oil from many zones with different reservoir properties. The aim of this study is to simulate and model the Qishn sandstone reservoir to provide more understanding of its properties. The available, core plugs, petrophysical, PVT, pressure and production datasets, as well as the seismic structural and geologic information, are all integrated and used in the simulation process. Eclipse simulator was used as a powerful tool for reservoir modeling. A simplified approach based on a pseudo steady-state productivity index and a material balance relationship between the aquifer pressure and the cumulative influx, is applied. The petrophysical properties of the Qishn sandstone reservoir are mainly investigated based on the well logging and core plug analyses. Three reservoir zones of good hydrocarbon potentiality are indicated and named from above to below as S1A, S1C and S2. Among of these zones, the S1A zone attains the best petrophysical and reservoir quality properties. It has an average hydrocarbon saturation of more than 65%, high effective porosity up to 20% and good permeability record (66 mD). The reservoir structure is represented by faulted anticline at the middle of the study with a down going decrease in geometry from S1A zone to S2 zone. It is limited by NE-SW and E-W bounding faults, with a weak aquifer connection from the east. The analysis of pressure and PVT data has revealed that the reservoir fluid type is dead oil with very low gas liquid ratio (GLR). The simulation results indicate heterogeneous reservoir associated with weak aquifer, supported by high initial water saturation and high water cut. Initial oil in place is estimated to be around 628 MM BBL, however, the oil recovery during the period of production is very low (<10%) because of the high water cut due to the fractures associated with many faults. Hence, secondary and

  12. Optimal Complexity in Reservoir Modeling of an Eolian Sandstone for Carbon Sequestration Simulation

    Science.gov (United States)

    Li, S.; Zhang, Y.; Zhang, X.

    2011-12-01

    Geologic Carbon Sequestration (GCS) is a proposed means to reduce atmospheric concentrations of carbon dioxide (CO2). Given the type, abundance, and accessibility of geologic characterization data, different reservoir modeling techniques can be utilized to build a site model. However, petrophysical properties of a formation can be modeled with simplifying assumptions or with greater detail, the later requiring sophisticated modeling techniques supported by additional data. In GCS where cost of data collection needs to be minimized, will detailed (expensive) reservoir modeling efforts lead to much improved model predictive capability? Is there an optimal level of detail in the reservoir model sufficient for prediction purposes? In Wyoming, GCS into the Nugget Sandstone is proposed. This formation is a deep (>13,000 ft) saline aquifer deposited in eolian environments, exhibiting permeability heterogeneity at multiple scales. Based on a set of characterization data, this study utilizes multiple, increasingly complex reservoir modeling techniques to create a suite of reservoir models including a multiscale, non-stationary heterogeneous model conditioned to a soft depositional model (i.e., training image), a geostatistical (stationary) facies model without conditioning, a geostatistical (stationary) petrophysical model ignoring facies, and finally, a homogeneous model ignoring all aspects of sub-aquifer heterogeneity. All models are built at regional scale with a high-resolution grid (245,133,140 cells) from which a set of local simulation models (448,000 grid cells) are extracted. These are considered alternative conceptual models with which pilot-scale CO2 injection is simulated (50 year duration at 1/10 Mt per year). A computationally efficient sensitivity analysis (SA) is conducted for all models based on a Plackett-Burman Design of Experiment metric. The SA systematically varies key parameters of the models (e.g., variogram structure and principal axes of intrinsic

  13. Reservoir characterization of the Snorre Field

    OpenAIRE

    Gjestvang, Jørgen

    2016-01-01

    Master's thesis in Petroleum engineering The fluvial sandstone in the Snorre field consists of braided to meander streams deposited in arid and in humid climate that show a clear differences in the sedimentology and reservoir properties, especially the silt content in large part of the reservoir which decrease the reservoir properties and water saturation. The heterogeneity of these fluvial formations combined with the faulting history makes this reservoir highly complex with many local an...

  14. Reservoir resistivity characterization incorporating flow dynamics

    KAUST Repository

    Arango, Santiago

    2016-04-07

    Systems and methods for reservoir resistivity characterization are provided, in various aspects, an integrated framework for the estimation of Archie\\'s parameters for a strongly heterogeneous reservoir utilizing the dynamics of the reservoir are provided. The framework can encompass a Bayesian estimation/inversion method for estimating the reservoir parameters, integrating production and time lapse formation conductivity data to achieve a better understanding of the subsurface rock conductivity properties and hence improve water saturation imaging.

  15. Response to Comment by H. Lough, Department of Civil Engineering, University of Canterbury, Christchurch, New Zealand, on the Paper " Stream Depletion Predictions using Pumping Test Data from A Heterogeneous Stream-Aquifer System (A Case Study from the Gr

    Energy Technology Data Exchange (ETDEWEB)

    Kollet, S J; Zlotnik, V A

    2004-12-20

    We thank H. Lough for her interest in our data set and the attempt to re-analyze our results (Kollet and Zlotnik, 2003) using the recent model by Hunt (2003). We welcome others to share our unique data set of the pumping test from the Prairie Creek site, Nebraska, USA. Nevertheless we believe that this particular attempt failed, because H. Lough selected a wrong model of semi-confined aquifer conditions for the interpretation of the pumping test data, which was collected in an unconfined aquifer. H. Lough based her selection on the three distinct drawdown segments observed during the test. It is well known that geologically distinct aquifers can yield a three-segment drawdown response under pumping conditions (e.g., Streltsova, 1988). Examples include unconfined aquifers (e.g., Neuman, 1972; Moench, 1997), aquifers with double porosity or fractures (e.g., Barenblatt et al., 1960; Boulton and Streltsova-Adams, 1978), and (semi-) confined aquifers in contact with aquitards (e.g. Cooley and Case, 1973; Moench, 1985). At the Prairie Creek site the aquifer is unconfined. The interpretation of the pumping test data collected at the site using type curves that are valid for an aquifer-aquitard system is a mistake. In fact, this approach illustrates a typical problem associated with inverse modeling: drastically different models can closely reproduce a system response and yield some parameter estimates, although the models do not represent the real system adequately. Here, the improper model yields some parameter estimates for an aquitard, although the aquitard does not exist at the Prairie Creek test site. We must also unequivocally state that the model by Hunt (2003) is clearly formulated and correct for stream-aquifer-aquitard systems within the stated limitations (pumping wells screened only in the lowest stratigraphic layer, etc.). However, the Hunt (1999) or BZT (Butler et al., 2001) models should be used for interpreting pumping tests near streams in non

  16. Aquifer Storage Recovery (ASR) of chlorinated municipal drinking water in a confined aquifer

    Science.gov (United States)

    Izbicki, John A.; Petersen, Christen E.; Glotzbach, Kenneth J.; Metzger, Loren F.; Christensen, Allen H.; Smith, Gregory A.; O'Leary, David R.; Fram, Miranda S.; Joseph, Trevor; Shannon, Heather

    2010-01-01

    About 1.02 x 106 m3 of chlorinated municipal drinking water was injected into a confined aquifer, 94-137 m below Roseville, California, between December 2005 and April 2006. The water was stored in the aquifer for 438 days, and 2.64 x 106 m3 of water were extracted between July 2007 and February 2008. On the basis of Cl data, 35% of the injected water was recovered and 65% of the injected water and associated disinfection by-products (DBPs) remained in the aquifer at the end of extraction. About 46.3 kg of total trihalomethanes (TTHM) entered the aquifer with the injected water and 37.6 kg of TTHM were extracted. As much as 44 kg of TTHMs remained in the aquifer at the end of extraction because of incomplete recovery of injected water and formation of THMs within the aquifer by reactions with freechlorine in the injected water. Well-bore velocity log data collected from the Aquifer Storage Recovery (ASR) well show as much as 60% of the injected water entered the aquifer through a 9 m thick, high-permeability layer within the confined aquifer near the top of the screened interval. Model simulations of ground-water flow near the ASR well indicate that (1) aquifer heterogeneity allowed injected water to move rapidly through the aquifer to nearby monitoring wells, (2) aquifer heterogeneity caused injected water to move further than expected assuming uniform aquifer properties, and (3) physical clogging of high-permeability layers is the probable cause for the observed change in the distribution of borehole flow. Aquifer heterogeneity also enhanced mixing of native anoxic ground water with oxic injected water, promoting removal of THMs primarily through sorption. A 3 to 4-fold reduction in TTHM concentrations was observed in the furthest monitoring well 427 m downgradient from the ASR well, and similar magnitude reductions were observed in depth-dependent water samples collected from the upper part of the screened interval in the ASR well near the end of the extraction

  17. Reservoir management

    International Nuclear Information System (INIS)

    Satter, A.; Varnon, J.E.; Hoang, M.T.

    1992-01-01

    A reservoir's life begins with exploration leading to discovery followed by delineation of the reservoir, development of the field, production by primary, secondary and tertiary means, and finally to abandonment. Sound reservoir management is the key to maximizing economic operation of the reservoir throughout its entire life. Technological advances and rapidly increasing computer power are providing tools to better manage reservoirs and are increasing the gap between good and neutral reservoir management. The modern reservoir management process involves goal setting, planning, implementing, monitoring, evaluating, and revising plans. Setting a reservoir management strategy requires knowledge of the reservoir, availability of technology, and knowledge of the business, political, and environmental climate. Formulating a comprehensive management plan involves depletion and development strategies, data acquisition and analyses, geological and numerical model studies, production and reserves forecasts, facilities requirements, economic optimization, and management approval. This paper provides management, engineers geologists, geophysicists, and field operations staff with a better understanding of the practical approach to reservoir management using a multidisciplinary, integrated team approach

  18. High heterogeneity of malaria transmission and a large sub-patent and diverse reservoir of infection in Wusab As Safil district, Republic of Yemen.

    Science.gov (United States)

    Cook, Jackie; Grignard, Lynn; Al-Eryani, Samira; Al-Selwei, Mustafa; Mnzava, Abraham; Al-Yarie, Hafed; Rand, Alison; Kleinschmidt, Immo; Drakeley, Chris

    2016-04-08

    Yemen remains the country with the highest malaria transmission within the Arabian Peninsula and a source of imported cases to neighbouring countries. This study collected samples from individuals resident in a valley in Western Yemen as a baseline to examine infection prevalence for a future trial. As well as rapid diagnostic test (RDT) and microscopy, a filter paper blood spot was collected for molecular and serological analyses. Samples were collected from 2261 individuals from 12 clusters across a study area of approximately 100 km(2). Plasmodium falciparum infection prevalence was 12.4, 11.1 and 19.6% by RDT, microscopy and polymerase chain reaction (PCR), respectively. RDT and microscopy did not detect 45% of infections present, suggesting many infections were low-density. Infection prevalence and seroprevalence were highly heterogeneous between clusters, with evidence of higher exposure in clusters close to the wadi. The mean multiplicity of infection (MOI) was 2.3 and high heterozygosity and allelic richness were detected. This highly diverse parasite population suggests a high degree of transmissibility and coupled with the substantial proportion of low-density infections, may pose challenges for malaria control and elimination efforts.

  19. An Aquifer Thermal Energy Storage (ATES) System for Continuous and Sustainable Cold Supply in Oman

    Science.gov (United States)

    Winterleitner, G.; Schütz, F.; Huenges, E.

    2016-12-01

    The aim of the GeoSolCool research programme between the German Research Centre for Geoscience (GFZ) and The Research Council of Oman (TRC) is the development of an innovative and sustainable cooling system in combination with an aquifer thermal energy storage system in northern Oman. An integral part of this project is the design of a subsurface aquifer reservoir system for storage of thermal energy through hot water injection. An accurate characterisation of potential storage horizons is thus essential to ensure optimal efficiency of the cooling system. The study area, 40 km west of Muscat is characterised by a thick Cenozoic mixed carbonate-siliciclastic sedimentary succession, containing at least 3 aquifer horizons. We used a multidisciplinary approach for the initial ATES development phase, including geological fieldwork dovetailed with remote sensing analyses, thin-section analyses, geological modelling and reservoir fluid flow forecasting. First results indicate two potential storage horizons: (1) a Miocene-aged clastic-dominated alluvial fan system and (2) an Eocene carbonate sequence. The alluvial fan system is a more than 300 m thick, coarse clastic (mainly gravels and sandstones) succession of coalesced individual fans. Thin-section analyses showed that hydraulic parameters are favourable for the gravel and sandstone intervals but reservoir architecture is complex due to multiple generations of interconnecting fans with highly heterogeneous facies distributions. The Eocene carbonates were deposited in a carbonate ramp setting, strongly influenced by currents and storm events. Individual facies belts extend over kilometres and thus horizontal reservoir connectivity is expected to be good with minor facies variability. Thin-section analyses showed that especially the fossil-rich sections show good storage qualities. Fluid flow forecasting indicate that both potential horizons have good to very good storage characteristics. However, intense diagenetic

  20. Selection of production strategy in heterogeneous reservoirs under uncertainty with emphasis on analysis of wells; Selecao de estrategia de producao em campos com fortes heterogeneidades sob incertezas com enfase na analise de pocos

    Energy Technology Data Exchange (ETDEWEB)

    Botechia, Vinicius E.; Schiozer, Denis J. [Universidade Estadual de Campinas (DEP/FEM/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Engenharia de Petroleo

    2012-07-01

    The selection of a good production strategy for an oil field is a very important task, because it should enable the field to produce a quantity of hydrocarbons efficiently, in order to maximize the performance of the reservoir. This task, however, is extremely complex due to the large number of variables involved and possible alternatives. In scenarios under uncertainty, this complexity is even greater, since risks increase. The studies that focus on methodologies to select production strategies take into account, in most cases, only field indicators in the process. However, in heterogeneous fields and in scenarios under uncertainty, the behavior of the wells may have a very large range between the scenarios, due mainly to differences in simulation models in these cases. Thus, this paper proposes an approach to analyze the behavior of wells in the selection of production strategy in order to make the optimization process more efficient, increasing the average economic return on the considered scenarios or decreasing the risk involved in the process. The results showed that this type of analysis can provide new alternatives of strategies or can give greater robustness to the chosen strategy. (author)

  1. Megaporosity and permeability of Thalassinoides-dominated ichnofabrics in the Cretaceous karst-carbonate Edwards-Trinity aquifer system, Texas

    Science.gov (United States)

    Cunningham, Kevin J.; Sukop, Michael C.

    2012-01-01

    Current research has demonstrated that trace fossils and their related ichnofabrics can have a critical impact on the fluid-flow properties of hydrocarbon reservoirs and groundwater aquifers. Most petroleum-associated research has used ichnofabrics to support the definition of depositional environments and reservoir quality, and has concentrated on siliciclastic reservoir characterization and, to a lesser degree, carbonate reservoir characterization (for example, Gerard and Bromley, 2008; Knaust, 2009). The use of ichnology in aquifer characterization has almost entirely been overlooked by the hydrologic community because the dynamic reservoir-characterization approach has not caught on with hydrologists and so hydrology is lagging behind reservoir engineering in this area (de Marsily and others, 2005). The objective of this research is to show that (1) ichnofabric analysis can offer a productive methodology for purposes of carbonate aquifer characterization, and (2) a clear relation can exist between ichnofabrics and groundwater flow in carbonate aquifers.

  2. Geopressured-geothermal aquifers. Final contract report

    Energy Technology Data Exchange (ETDEWEB)

    1983-08-01

    Task 1 is to provide petrophysical and reservoir analysis of wells drilled into geopressured-geothermal aquifers containing dissolved methane. The list of Design Wells and Wells of Opportunity analyzed: Fairfax Foster Sutter No. 2 (WOO), Pleasant Bayou No. 2 (Design), Amoco Fee No. 1 (Design), G.M. Koelemay No. 1 (WOO), Gladys McCall No. 1 (Design), P.R. Girouard No. 1 (WOO), and Crown Zellerbach No. 2 (WOO). Petrophysical and reservoir analysis of the above wells were performed based on availability of data. The analysis performed on each well, the assumptions made during simulation, and conclusions reached.

  3. Modelos conceptuales de abundancia de fitoplancton asociados a la heterogeneidad espacial en el Embalse Rapel (Chile central Conceptual models of phytoplankton abundance associated to spatial heterogeneity at the Rapel reservoir (central Chile

    Directory of Open Access Journals (Sweden)

    GINGER MARTÍNEZ

    2003-06-01

    El Muro, la mayor variabilidad fue explicada por la concentración de compuestos nitrogenados, siendo el nitrato particularmente importante en el sector Alhué y el amonio en el sector El Muro. Estos resultados sugieren un control diferencial de la abundancia fitoplanctónica asociada a los diferentes sectores del embalse. Mientras que en el sector Las Balsas predominaría un control externo generado por la descarga de los tributarios, en la estación El Muro se postula un control interno y producido por la generación in situ de amonio. La significativa asociación a nitrato y nitrógeno orgánico detectada en la estación Alhué indicaría un control doble en la generación del patrón fitoplanctónicoHeterogeneous morphology generates abundance patterns and a differential response of the planktonic assemblages in regulated aquatic systems. This is the case at the Rapel reservoir (34º10' S, 71º29' W. A longitudinal morphoedaphic gradient and localized hydrodynamic conditions produce spatial complexity in this type-dendritic basin, that has been proposed as probable causal mechanism of the main diferences in phytoplankton abundance among areas inside of the reservoir. In this study, mechanisms and conceptual models of phytoplankton abundance are proposed, describing algae distribution patterns in three reservoir areas: Las Balsas, Alhué and El Muro. Also, the main predictive variables were identified which lead to propose a specific functioning model in each reservoir area. A data base published was used in order to obtain phytoplankton total abundance and physical and chemical variables from each station sampling that represent the reservoir areas, including the Confluencia area localized between Las Balsas and El Muro areas. Cluster and principal components analysis were applied in order to describe the spatial pattern and a multiple linear regression analysis was utilized to identify predictive variables in each sampling station. Results showed two significant

  4. Assessing aquifer storage and recovery feasibility in the Gulf Coastal Plains of Texas

    OpenAIRE

    W. Benjamin Smith; Gretchen R. Miller; Zhuping Sheng

    2017-01-01

    Study region: The Gulf Coast and Carrizo-Wilcox aquifer systems in the Gulf Coastal Plains of Texas. Study focus: Aquifer storage and recovery is a water storage alternative that is underutilized in Texas, a state with both long periods of drought and high intensity storms. Future water storage plans in Texas almost exclusively rely on surface reservoirs, subject to high evaporative losses. This study seeks to identify sites where aquifer storage and recovery (ASR) may be successful, especial...

  5. Geoscience/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian Basin, West Texas and New Mexico-stratigraphic hierarchy and cycle stacking facies distribution, and interwell-scale heterogeneity: Grayburg Formation, New Mexico. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Barnaby, R.J.; Ward, W.B.; Jennings, J.W. Jr.

    1997-06-01

    The Grayburg Formation (middle Guadalupian) is a major producing interval in the Permian Basin and has yielded more than 2.5 billion barrels of oil in West Texas. Grayburg reservoirs have produced, on average, less than 30 percent of their original oil in place and are undergoing secondary and tertiary recovery. Efficient design of such enhanced recovery programs dictates improved geological models to better understand and predict reservoir heterogeneity imposed by depositional and diagenetic controls. The Grayburg records mixed carbonate-siliciclastic sedimentation on shallow-water platforms that rimmed the Delaware and Midland Basins. Grayburg outcrops in the Guadalupe and Brokeoff Mountains region on the northwest margin of the Delaware Basin present an opportunity to construct a detailed, three-dimensional image of the stratigraphic and facies architecture. This model can be applied towards improved description and characterization of heterogeneity in analogous Grayburg reservoirs. Four orders of stratigraphic hierarchy are recognized in the Grayburg Formation. The Grayburg represents a long-term composite sequence composed of four high-frequency sequences (HFS 1-4). Each HFS contains several composite cycles comprising two or more cycles that define intermediate-scale transgressive-regressive successions. Cycles are the smallest scale upward-shoaling vertical facies successions that can be recognized and correlated across various facies tracts. Cycles thus form the basis for establishing the detailed chronostratigraphic correlations needed to delineate facies heterogeneity.

  6. Coupling fracture facies with in situ permeability measurements to generate stochastic simulations of tight carbonate aquifer properties: example from the Lower Cretaceous aquifer, Northern Provence, SE France

    Science.gov (United States)

    Bruna, Pierre-Olivier; Guglielmi, Yves; Viseur, Sophie; Lamarche, Juliette

    2015-04-01

    The relationships between fracture facies and permeability distribution have been explored using a well-constrained 3D implicit structural model of hemipelagic low porosity/low permeability carbonate from the Northern Provence region, SE France. Fracture and permeability facies were determined using an extensive dataset of 99 hydrogeological boreholes wells. Data processing was undertaken using a step-by-step approach, involving: i) identification of the fracture facies based on well logs detailing structure and stratigraphy ; ii) determination of permeability facies from the a priori correlation between the dimension of the hydraulic radius of influence (deduced from slug test analyses) and the type of reservoir heterogeneity (fissure, fracture, fault zone, etc.); iii) three dimensional plot of fracture and permeability facies in the geological model using a variographic analysis of data. Thirty-three sequential indicator simulations (SIS) were realised on both fracture and permeability facies. Finally, a connectivity algorithm was developed to compute the probability of connection between selected infiltration areas and the major aquifer springs via moderate-to high-permeability geological bodies. Key results are: i) fault zones have a greater role in controlling permeability facies distribution than on fracture facies repartition; ii) there is little correlation between permeability and fracture facies distributions ; iii) connectivity results highlight the compartmentalization of aquifers in the Cadarache area, the extensions of permeable geological bodies being limited by the N130 faults.

  7. Coupling fracture facies with in-situ permeability measurements to generate stochastic simulations of tight carbonate aquifer properties: Example from the Lower Cretaceous aquifer, Northern Provence, SE France

    Science.gov (United States)

    Bruna, Pierre-Olivier; Guglielmi, Yves; Viseur, Sophie; Lamarche, Juliette; Bildstein, Olivier

    2015-10-01

    The relationships between fracture facies and permeability distribution have been explored using a well-constrained 3D implicit structural model of hemipelagic low porosity/low permeability carbonate from the Northern Provence region, SE France. Fracture and permeability facies were determined using an extensive dataset of 99 hydrogeological wells. Data processing was undertaken using a step-by-step approach, involving: (i) identification of the fracture facies based on well logs detailing structure and stratigraphy; (ii) determination of permeability facies from the a priori correlation between the dimension of the hydraulic radius of influence (deduced from slug test analyses) and the type of reservoir heterogeneity (fissure, fracture, fault zone, etc.); (iii) three dimensional plot of fracture and permeability facies in the geological model using a variographic analysis of data. Thirty-three sequential indicator simulations (SIS) based on geostatistic analyses were realised on both fracture and permeability facies. Finally, a connectivity algorithm was developed to compute the probability of connection between selected infiltration areas and the major aquifer springs via moderate- to high-permeability geological bodies. Key results are: (i) fault zones have a greater role in controlling permeability facies distribution than on fracture facies repartition; (ii) there is little correlation between permeability and fracture facies distributions; (iii) connectivity results highlight the compartmentalisation of aquifers in the Cadarache area, the extensions of permeable geological bodies being limited by the N130 faults.

  8. High-resolution Fracture Characterization of a Siliciclastic Aquifer Targeted for CO2 Sequestration, Svalbard, Norway

    NARCIS (Netherlands)

    Ogata, Kei; Senger, Kim; Braathen, Alvar; Olaussen, Snorre; Tveranger, Jan

    2013-01-01

    SUMMARY The target siliciclastic aquifer investigated by the Longyearbyen CO2 Lab as a possible test-scale CO2 storage unit is a dual-permeability reservoir characterized by fractured, tight lithologies. By integrating borehole and outcrop data, the reservoir section has been subdivided in intervals

  9. Upscaling of CO2-Brine Flow with Capillary Heterogeneity Effects

    Science.gov (United States)

    Rabinovich, A.; Itthisawatpan, K.; Durlofsky, L. J.

    2014-12-01

    Large-scale simulation of CO2 storage operations can be expensive computationally, particularly when the effects of fine-scale capillary pressure heterogeneity are included. These effects, which are often ignored in traditional reservoir simulation, can significantly impact the movement of CO2 and should therefore be included in carbon storage simulations. The application of upscaling techniques that handle capillary heterogeneity could lead to reductions in computational cost, though general and robust procedures for this problem have yet to be presented. In this work, we develop and apply a new upscaling technique for two-phase flow in heterogeneous porous media with capillary heterogeneity effects. Fine-scale capillary pressure is modeled using the Leverett J-function and varies with permeability. We show that accurate upscaled models can be constructed by first upscaling capillary pressure under the assumption of capillary equilibrium, and then computing coarse-scale relative permeability functions using a global dynamic upscaling procedure. Some of the key numerical treatments associated with the overall procedure, such as near-well upscaling and the use of global coarse-scale iteration to improve model accuracy, will be described. The new upscaling approach is applied to synthetic heterogeneous two-dimensional aquifer models with flow driven by CO2 injection. Injection via both vertical and horizontal wells is considered. Fine-scale reference results are compared with coarse-scale results generated using both the new upscaling approach and alternative (simpler) methods. In general, of the techniques considered, our new approach is shown to provide the best overall accuracy. Different CO2 injection rates and well locations are considered, which allows us to explore the robustness of the upscaled model. Various strategies for enhancing model robustness will also be applied and assessed.

  10. Application of integrated reservoir management and reservoir characterization to optimize infill drilling, Class II

    Energy Technology Data Exchange (ETDEWEB)

    Bergeron, Jack; Blasingame, Tom; Doublet, Louis; Kelkar, Mohan; Freeman, George; Callard, Jeff; Moore, David; Davies, David; Vessell, Richard; Pregger, Brian; Dixon, Bill; Bezant, Bryce

    2000-03-16

    The major purpose of this project was to demonstrate the use of cost effective reservoir characterization and management tools that will be helpful to both independent and major operators for the optimal development of heterogeneous, low permeability carbonate reservoirs such as the North Robertson (Clearfork) Unit.

  11. Water Influx, and Its Effect on Oil Recovery: Part 1. Aquifer Flow, SUPRI TR-103

    Energy Technology Data Exchange (ETDEWEB)

    Brigham, William E.

    1999-08-09

    Natural water encroachment is commonly seen in many oil and gas reservoirs. In fact, overall, there is more water than oil produced from oil reservoirs worldwide. Thus it is clear that an understanding of reservoir/aquifer interaction can be an important aspect of reservoir management to optimize recovery of hydrocarbons. Although the mathematics of these processes are difficult, they are often amenable to analytical solution and diagnosis. Thus this will be the ultimate goal of a series of reports on this subject. This first report deals only with aquifer behavior, so it does not address these important reservoir/aquifer issues. However, it is an important prelude to them, for the insight gained gives important clues on how to address reservoir/aquifer problems. In general when looking at aquifer flow, there are two convenient inner boundary conditions that can be considered; constant pressure or constant flow rate. There are three outer boundary conditions that are convenient to consider; infinite, closed and constant pressure. And there are three geometries that can be solved reasonably easily; linear, radial and spherical. Thus there are a total of eighteen different solutions that can be analyzed.

  12. Energy Resources of Water-Bearing Geopressured Reservoirs-Tertiary Formations, Northwestern Gulf of Mexico (Summary Ressources énergétiques des réservoirs aquifères à pressions géostratégiques dans les formations tertiaires du golfe du Mexique (résumé

    Directory of Open Access Journals (Sweden)

    Bebout D. G.

    2006-11-01

    Full Text Available Estimates for the total gas resource in place in geopressured Tertiary sandstone reservoirs along the United States Gulf Coast range from 3,000 to 100,000 tcf 185 to 2,832 trillion cu m. This wide range in estimates was the incentive for initiative research effort in Texas and Louisiane to obtain more reliable data on all aspects of developing the available heat and hydraulic energy present in these aquifers in addition to the methane. All resource calculations are based on interpretations of total sandstone thickness, lateral extent of reservoirs, porosity and permeability, reservoir drive, salinity, temperature, pressure, and methane solubility. Diverse estimates arise from inadequate knowledge concerning these critical parameters. Regional and detailed local geologic studies have been conducted ta delineate prospective areas for testing the geopressured resource. A prospective area should have reservoir volume of 3 Cu mi (12 cu km, minimum permeability of 20 mD, and fluid temperatures of 300°F (150°C. A geothermal designed test well has been drilled in Brazoria County, Texas, in order to test the potential of producing up to 40,000 barrels of water per day from a geopressured reservoir. The reservoir consists of 250 to 300 ft (75 to 90 m of sandstone with core permeabilities between 40 and 60 mD and fluid temperatures from 300 to 350°F (159 to 177°C. The test period will continue for a 2-year period and, with other designed tests in Texas and Louisiana will provide invaluable data concerning high-volume production over long periods of time. Les estimations pour les ressources totales de gaz dans les réservoirs sableux tertiaires à pressions géostatiques le long de la Gulf Coast des Etats-Unis sont corises entre 3000 et 100 000 tcf, soit 85 à 2832. 10. 12 m3. Cette large incertitude a incité la mise en oeuvre d'un effort extensif de recherche au Texas et en Louisiane en vue d'obtenir des données plus sûres sur tous les aspects du d

  13. Geochemistry, biota and natural background levels in an arsenic naturally contaminated volcanic aquifer

    Science.gov (United States)

    Preziosi, Elisabetta; Amalfitano, Stefano; Di Lorenzo, Tiziana; Parrone, Daniele; Rossi, David; Ghergo, Stefano; Lungarini, Silvia; Zoppini, Anna Maria

    2015-04-01

    The tight links between chemical and ecological status are largely acknowledged as for surface water bodies, while aquifers are still considered as hidden groundwater reservoirs, rather than ecosystems to be preserved. Geochemical and biological interactions play a key role in all subterranean processes, including the dynamics of the fate of anthropogenic contaminants. Studies on groundwater dependent ecosystems (GDE) were mainly focused on karst aquifers so far, but an increased awareness on the importance of water-rock interactions and methodological improvements in microbial ecology are rapidly increasing the level of characterization of groundwater ecosystems in various hydrogeological contexts. Similarly, knowledge about groundwater biodiversity is still limited, especially if porous habitats are concerned. Yet, groundwater and GDEs are populated by a diverse and highly adapted biota, dominated by crustaceans, which provide important ecosystem services and act as biological indicators of chemical and quantitative impact on groundwater resources. In a previous research (Amalfitano et al. 2014), we reported that the microbial community heterogeneity may reflect the lithological and hydrogeological complexity within volcanic and alluvial facies transition in a groundwater body. The quantitative tracking of the microbial community structure allowed disentangling the natural biogeochemical processes evolving within the aquifer flow path. The analyses of groundwater crustaceans assemblages may contribute to shed more light upon the state and dynamics of such ecosystems. In the present research, a comprehensive study of a water table aquifer flowing through a quaternary volcanic district is being performed, including the geochemical (inorganic) composition, the microbial composition, and the analysis of crustacean assemblages . Groundwater samples are periodically collected from private wells and springs under a low anthropic impact. The key issues within the

  14. Biscayne aquifer, southeast Florida

    Science.gov (United States)

    Klein, Howard; Hull, John E.

    1978-01-01

    Peak daily pumpage from the highly permeable, unconfined Biscayne aquifer for public water-supply systems in southeast Florida in 1975 was about 500 million gallons. Another 165 million gallons was withdrawn daily for irrigation. Recharge to the aquifer is primarily by local rainfall. Discharge is by evapotranspiration, canal drainage, coastal seepage, and pumping. Pollutants can enter the aquifer by direct infiltration from land surface or controlled canals, septic-tank and other drainfields, drainage wells, and solid-waste dumps. Most of the pollutants are concentrated in the upper 20 to 30 feet of the aquifer; public supply wells generally range in depth from about 75 to 150 feet. Dilution, dispersion, and adsorption tend to reduce the concentrations. Seasonal heavy rainfall and canal discharge accelerate ground-water circulation, thereby tending to dilute and flush upper zones of the aquifer. The ultimate fate of pollutants in the aquifer is the ocean, although some may be adsorbed by the aquifer materials en route to the ocean, and some are diverted to pumping wells. (Woodard-USGS)

  15. EPA Sole Source Aquifers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Information on sole source aquifers (SSAs) is widely used in assessments under the National Environmental Policy Act and at the state and local level. A national...

  16. Application of integrated reservoir management and reservoir characterization to optimize infill drilling

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

    This project has used a multi-disciplinary approach employing geology, geophysics, and engineering to conduct advanced reservoir characterization and management activities to design and implement an optimized infill drilling program at the North Robertson (Clearfork) Unit in Gaines County, Texas. The activities during the first Budget Period consisted of developing an integrated reservoir description from geological, engineering, and geostatistical studies, and using this description for reservoir flow simulation. Specific reservoir management activities were identified and tested. The geologically targeted infill drilling program currently being implemented is a result of this work. A significant contribution of this project is to demonstrate the use of cost-effective reservoir characterization and management tools that will be helpful to both independent and major operators for the optimal development of heterogeneous, low permeability shallow-shelf carbonate (SSC) reservoirs. The techniques that are outlined for the formulation of an integrated reservoir description apply to all oil and gas reservoirs, but are specifically tailored for use in the heterogeneous, low permeability carbonate reservoirs of West Texas.

  17. Ogallala Aquifer Mapping Program

    International Nuclear Information System (INIS)

    1984-10-01

    A computerized data file has been established which can be used efficiently by the contour-plotting program SURFACE II to produce maps of the Ogallala aquifer in 17 counties of the Texas Panhandle. The data collected have been evaluated and compiled into three sets, from which SURFACE II can generate maps of well control, aquifer thickness, saturated thickness, water level, and the difference between virgin (pre-1942) and recent (1979 to 1981) water levels. 29 figures, 1 table

  18. Superposition method used for treating oilfield interference in Iranian water-drive reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Hamid, K. [National Iranian South Oil Company, (Iran, Islamic Republic of)

    2003-07-01

    Water-drive oil fields that share a common aquifer are in hydrodynamic communication. Production from such fields is accompanied by pressure loss that manifests itself as pressure interference because the decline in pressure is transmitted through the aquifer to other fields even several miles away from a producing pool. In order to address the challenge of discovering new Iranian oil reserves, attention has focused on the efficient development of existing reservoirs. The Asmari reservoir consists of a high permeability sand and carbonate section in an elongated anticlinal structure. A drop in reservoir pressure was observed in field 'A' in 1974. This drop in pressure was noted one year after field 'B' in the same reservoir reached peak oil production of 1.1 MMBPD. A practical analytical method was developed to help the reservoir engineer analyze oilfield interference problems. Reservoir performance indicates that the aquifer from field 'A' has strong communication with field 'B'. The most practical method for treating oilfield interference in water-drive Iranian reservoirs was the superposition technique. It was emphasized that the impact of nearby fields should be considered in all reservoir simulations to accurately identify regional aquifer effects on flow rates and oil-water contact movement. 13 refs., 2 tabs., 4 figs.

  19. Application of Cutting-Edge 3D Seismic Attribute Technology to the Assessment of Geological Reservoirs for CO2 Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Christopher Liner; Jianjun Zeng; Po Geng Heather King Jintan Li; Jennifer Califf; John Seales

    2010-03-31

    The goals of this project were to develop innovative 3D seismic attribute technologies and workflows to assess the structural integrity and heterogeneity of subsurface reservoirs with potential for CO{sub 2} sequestration. Our specific objectives were to apply advanced seismic attributes to aide in quantifying reservoir properies and lateral continuity of CO{sub 2} sequestration targets. Our study area is the Dickman field in Ness County, Kansas, a type locality for the geology that will be encountered for CO{sub 2} sequestration projects from northern Oklahoma across the U.S. midcontent to Indiana and beyond. Since its discovery in 1962, the Dickman Field has produced about 1.7 million barrels of oil from porous Mississippian carbonates with a small structural closure at about 4400 ft drilling depth. Project data includes 3.3 square miles of 3D seismic data, 142 wells, with log, some core, and oil/water production data available. Only two wells penetrate the deep saline aquifer. Geological and seismic data were integrated to create a geological property model and a flow simulation grid. We systematically tested over a dozen seismic attributes, finding that curvature, SPICE, and ANT were particularly useful for mapping discontinuities in the data that likely indicated fracture trends. Our simulation results in the deep saline aquifer indicate two effective ways of reducing free CO{sub 2}: (a) injecting CO{sub 2} with brine water, and (b) horizontal well injection. A tuned combination of these methods can reduce the amount of free CO{sub 2} in the aquifer from over 50% to less than 10%.

  20. Aquifer storage and recovery: recent hydrogeological advances and system performance.

    Science.gov (United States)

    Maliva, Robert G; Guo, Weixing; Missimer, Thomas M

    2006-12-01

    Aquifer storage and recovery (ASR) is part of the solution to the global problem of managing water resources to meet existing and future freshwater demands. However, the metaphoric "ASR bubble" has been burst with the realization that ASR systems are more physically and chemically complex than the general conceptualization. Aquifer heterogeneity and fluid-rock interactions can greatly affect ASR system performance. The results of modeling studies and field experiences indicate that more sophisticated data collection and solute-transport modeling are required to predict how stored water will migrate in heterogeneous aquifers and how fluid-rock interactions will affect the quality of stored water. It has been well-demonstrated, by historic experience, that ASR systems can provide very large volumes of storage at a lesser cost than other options. The challenges moving forward are to improve the success rate of ASR systems, optimize system performance, and set expectations appropriately.

  1. Numerical simulation of the environmental impact of hydraulic fracturing of tight/shale gas reservoirs on near-surface ground water: background, base cases, shallow reservoirs, short-term gas and water transport

    Science.gov (United States)

    Researchers examined gas and water transport between a deep tight shale gas reservoir and a shallow overlying aquifer in the two years following hydraulic fracturing, assuming a pre-existing connecting pathway.

  2. EFFECT OF TOPOGRAPHIC AND GEOLOGIC HETEROGENEITIES ...

    African Journals Online (AJOL)

    Geologic heterogeneities and topographic variations in relation to aquifer distribution ad occurrence in Akwa Ibom State have been assessed based on geologic and geophysical studies sixty-six sounding points together with electric log responses of representative wells together with surface geologic data have been ...

  3. Semi-analytical solutions of groundwater flow in multi-zone (patchy) wedge-shaped aquifers

    Science.gov (United States)

    Samani, Nozar; Sedghi, Mohammad M.

    2015-03-01

    Alluvial fans are potential sites of potable groundwater in many parts of the world. Characteristics of alluvial fans sediments are changed radially from high energy coarse-grained deposition near the apex to low energy fine-grained deposition downstream so that patchy wedge-shaped aquifers with radial heterogeneity are formed. The hydraulic parameters of the aquifers (e.g. hydraulic conductivity and specific storage) change in the same fashion. Analytical or semi-analytical solutions of the flow in wedge-shaped aquifers are available for homogeneous cases. In this paper we derive semi-analytical solutions of groundwater flow to a well in multi-zone wedge-shaped aquifers. Solutions are provided for three wedge boundary configurations namely: constant head-constant head wedge, constant head-barrier wedge and barrier-barrier wedge. Derivation involves the use of integral transforms methods. The effect of heterogeneity ratios of zones on the response of the aquifer is examined. The results are presented in form of drawdown and drawdown derivative type curves. Heterogeneity has a significant effect on over all response of the pumped aquifer. Solutions help understanding the behavior of heterogeneous multi-zone aquifers for sustainable development of the groundwater resources in alluvial fans.

  4. CO2 perturbation in aquifers : reaction kinetics and metals behavior

    OpenAIRE

    Rillard, Jean

    2013-01-01

    The aim of this thesis was to investigate hydrogeochemical perturbation induced by CO2 in natural aquifers. In a first step, we used chemical data from natural CO2-rich hydrothermal water. We studied variation of fluid chemical composition as a function of CO2 content in order to evaluate reactivity of minerals composing the initial reservoir. Fluid chemical analyses showed decrease in pH, and systematic enrichment in alkalinity and major cations correlated to increase in CO2 content. Chemica...

  5. Electromagnetic Heating Methods for Heavy Oil Reservoirs

    International Nuclear Information System (INIS)

    Sahni, A.; Kumar, M.; Knapp, R.B.

    2000-01-01

    The most widely used method of thermal oil recovery is by injecting steam into the reservoir. A well-designed steam injection project is very efficient in recovering oil, however its applicability is limited in many situations. Simulation studies and field experience has shown that for low injectivity reservoirs, small thickness of the oil-bearing zone, and reservoir heterogeneity limits the performance of steam injection. This paper discusses alternative methods of transferring heat to heavy oil reservoirs, based on electromagnetic energy. They present a detailed analysis of low frequency electric resistive (ohmic) heating and higher frequency electromagnetic heating (radio and microwave frequency). They show the applicability of electromagnetic heating in two example reservoirs. The first reservoir model has thin sand zones separated by impermeable shale layers, and very viscous oil. They model preheating the reservoir with low frequency current using two horizontal electrodes, before injecting steam. The second reservoir model has very low permeability and moderately viscous oil. In this case they use a high frequency microwave antenna located near the producing well as the heat source. Simulation results presented in this paper show that in some cases, electromagnetic heating may be a good alternative to steam injection or maybe used in combination with steam to improve heavy oil production. They identify the parameters which are critical in electromagnetic heating. They also discuss past field applications of electromagnetic heating including technical challenges and limitations

  6. A review on hydraulic fracturing of unconventional reservoir

    OpenAIRE

    Quanshu Li; Huilin Xing; Jianjun Liu; Xiangchon Liu

    2015-01-01

    Hydraulic fracturing is widely accepted and applied to improve the gas recovery in unconventional reservoirs. Unconventional reservoirs to be addressed here are with very low permeability, complicated geological settings and in-situ stress field etc. All of these make the hydraulic fracturing process a challenging task. In order to effectively and economically recover gas from such reservoirs, the initiation and propagation of hydraulic fracturing in the heterogeneous fractured/porous media u...

  7. Geochemical detection of carbon dioxide in dilute aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, S; Hao, Y; Aines, R

    2009-03-27

    Carbon storage in deep saline reservoirs has the potential to lower the amount of CO{sub 2} emitted to the atmosphere and to mitigate global warming. Leakage back to the atmosphere through abandoned wells and along faults would reduce the efficiency of carbon storage, possibly leading to health and ecological hazards at the ground surface, and possibly impacting water quality of near-surface dilute aquifers. We use static equilibrium and reactive transport simulations to test the hypothesis that perturbations in water chemistry associated with a CO{sub 2} gas leak into dilute groundwater are important measures for the potential release of CO{sub 2} to the atmosphere. Simulation parameters are constrained by groundwater chemistry, flow, and lithology from the High Plains aquifer. The High Plains aquifer is used to represent a typical sedimentary aquifer overlying a deep CO{sub 2} storage reservoir. Specifically, we address the relationships between CO{sub 2} flux, groundwater flow, detection time and distance. The CO{sub 2} flux ranges from 10{sup 3} to 2 x 10{sup 6} t/yr (0.63 to 1250 t/m{sup 2}/yr) to assess chemical perturbations resulting from relatively small leaks that may compromise long-term storage, water quality, and surface ecology, and larger leaks characteristic of short-term well failure.

  8. Inverse modelling of aquifer parameters in basaltic rock with the help of pumping test method using MODFLOW software

    Directory of Open Access Journals (Sweden)

    Kanak Moharir

    2017-11-01

    The present study of estimation of aquifer factors such as transmissivity (T and storativity (S are vital for the evaluation of groundwater resources. There are several methods to estimate the accurate aquifer parameters (i.e. hydrograph analysis, pumping test, etc.. In initial days, these parameters are projected either by means of in-situ test or execution test on aquifer well samples carried in the laboratory. The simultaneous information on the hydraulic behavior of the well (borehole that provides on this method, the reservoir and the reservoir boundaries, are important for efficient aquifer and well data management and analysis. The most common in-situ test is pumping test performed on wells, which involves the measurement of the fall and increase of groundwater level with respect to time. The alteration in groundwater level (drawdown/recovery is caused due to pumping of water from the well. Theis (1935 was first to propose method to evaluate aquifer parameters from the pumping test on a bore well in a confined aquifer. It is essential to know the transmissivity (T = Kb, where b is the aquifer thickness; pumping flow rate, Q = TW (dh/dl flow through an aquifer and storativity (confined aquifer: S = bSs, unconfined: S = Sy, for the characterization of the aquifer parameters in an unknown area so as to predict the rate of drawdown of the groundwater table/potentiometric surface throughout the pumping test of an aquifer. The determination of aquifer's parameters is an important basis for groundwater resources evaluation, numerical simulation, development and protection as well as scientific management. For determining aquifer's parameters, pumping test is a main method. A case study shows that these techniques have been fast speed and high correctness. The results of parameter's determination are optimized so that it has important applied value for scientific research and geology engineering preparation.

  9. Initial in Situ Measurements of Perennial Meltwater Storage in the Greenland Firn Aquifer

    Science.gov (United States)

    Koenig, Lora S.; Miege, Clement; Forster, Richard R.; Brucker, Ludovic

    2014-01-01

    A perennial storage of water in a firn aquifer was discovered in southeast Greenland in 2011. We present the first in situ measurements of the aquifer, including densities and temperatures. Water was present at depths between approx. 12 and 37m and amounted to 18.7 +/- 0.9 kg in the extracted core. The water filled the firn to capacity at approx. 35m. Measurements show the aquifer temperature remained at the melting point, representing a large heat reservoir within the firn. Using model results of liquid water extent and aquifer surface depth from radar measurements, we extend our in situ measurements to the Greenland ice sheet. The estimated water volume is 140 +/- 20 Gt, representing approx. 0.4mm of sea level rise (SLR). It is unknown if the aquifer temporary buffers SLR or contributes to SLR through drainage and/or ice dynamics.

  10. Production Optimization of Oil Reservoirs

    DEFF Research Database (Denmark)

    Völcker, Carsten

    With an increasing demand for oil and diculties in nding new major oil elds, research on methods to improve oil recovery from existing elds is more necessary now than ever. The subject of this thesis is to construct ecient numerical methods for simulation and optimization of oil recovery...... programming (SQP) with line-search and BFGS approximations of the Hessian, and the adjoint method for ecient computation of the gradients. We demonstrate that the application of NMPC for optimal control of smart-wells has the potential to increase the economic value of an oil reservoir....... with emphasis on optimal control of water ooding with the use of smartwell technology. We have implemented immiscible ow of water and oil in isothermal reservoirs with isotropic heterogenous permeability elds. We use the method of lines for solution of the partial differential equation (PDE) system that governs...

  11. Geological exploration for a high-temperature aquifer thermal energy storage (HT-ATES) system: a case study from Oman

    Science.gov (United States)

    Winterleitner, Gerd; Schütz, Felina; Huenges, Ernst

    2017-04-01

    A collaborative research programme between the German Research Centre for Geoscience, Potsdam (GFZ) and The Research Council of Oman (TRC) is underway, which aims to develop and implement an innovative concept of a sustainable thermally driven cooling system in combination with a HT-ATES in northern Oman. The system will use an absorption chiller for cold supply, which nominally requires water of around 100°C as energy source. Solar collectors will provide this thermal energy and energy surpluses during daytimes will be stored to ensure a continuous operation of the cooling system. An integral part of this project is, therefore, the development of an efficient HT-ATES (100°C), which is based on temporary storage and recovery of thermal energy through hot water injection in subsurface aquifer horizons. Thus, an accurate thermal and fluid flow characterisation of potential reservoir horizons is essential to ensure optimal efficiency of the cooling system. The study area is located in the Al Khwad area, approximately 40 km to the west of Muscat. The area is characterised by a thick Cenozoic mixed carbonate-siliciclastic sedimentary succession, containing at least 3 aquifer horizons. We use a multidisciplinary approach for the initial ATES exploration and development phase, including traditional geological fieldwork dovetailed with virtual outcrop geology, thin-section analyses, geological modelling and reservoir fluid flow forecasting analyses. Our first results indicate two potential storage horizons: (1) a Miocene-aged clastic-dominated alluvial fan system and (2) an Eocene carbonate-dominated sequence. The alluvial fan system is characterised by a more than 300 m thick, coarse-clastic succession of coalesced individual fans. Thermal and hydraulic parameters are favourable for gravel and sandstone intervals but reservoir architecture is complex due to multiple generations of interconnecting fans with highly heterogeneous facies distributions. The Eocene carbonates

  12. Relationship between tectonic structures and hydrogeochemical compartmentalization in aquifers: Example of the “Jeffara de Medenine” system, south–east Tunisia

    Directory of Open Access Journals (Sweden)

    Hayet Chihi

    2015-09-01

    The kriged maps of major-ion concentrations and of total dissolved solids in the aquifers were then analyzed and compared with the reservoir facies distribution for each compartment, the geometric characteristics of the aquifer, and the piezometric level trends. This allowed to characterize the hydraulic behavior of the Medenine fault and to understand the underlying physical and chemical processes having led to the spatial distribution of the geochemical properties, and thus, the hydrogeochemical functioning of the aquifers.

  13. Reservoir Characterization, Production Characteristics, and Research Needs for Fluvial/Alluvial Reservoirs in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Cole, E.L.; Fowler, M.L.; Jackson, S.R.; Madden, M.P.; Raw-Schatzinger, V.; Salamy, S.P.; Sarathi, P.; Young, M.A.

    1999-04-28

    The Department of Energy's (DOE's) Oil Recovery Field Demonstration Program was initiated in 1992 to maximize the economically and environmentally sound recovery of oil from known domestic reservoirs and to preserve access to this resource. Cost-shared field demonstration projects are being initiated in geology defined reservoir classes which have been prioritized by their potential for incremental recovery and their risk of abandonment. This document defines the characteristics of the fifth geological reservoir class in the series, fluvial/alluvial reservoirs. The reservoirs of Class 5 include deposits of alluvial fans, braided streams, and meandering streams. Deposit morphologies vary as a complex function of climate and tectonics and are characterized by a high degree of heterogeneity to fluid flow as a result of extreme variations in water energy as the deposits formed.

  14. FEWA: a Finite Element model of Water flow through Aquifers

    International Nuclear Information System (INIS)

    Yeh, G.T.; Huff, D.D.

    1983-11-01

    This report documents the implementation and demonstration of a Finite Element model of Water flow through Aquifers (FEWA). The particular features of FEWA are its versatility and flexibility to deal with as many real-world problems as possible. Point as well as distributed sources/sinks are included to represent recharges/pumpings and rainfall infiltrations. All sources/sinks can be transient or steady state. Prescribed hydraulic head on the Dirichlet boundaries and fluxes on Neumann or Cauchy boundaries can be time-dependent or constant. Source/sink strength over each element and node, hydraulic head at each Dirichlet boundary node, and flux at each boundary segment can vary independently of each other. Either completely confined or completely unconfined aquifers, or partially confined and partially unconfined aquifers can be dealt with effectively. Discretization of a compound region with very irregular curved boundaries is made easy by including both quadrilateral and triangular elements in the formulation. Large-field problems can be solved efficiently by including a pointwise iterative solution strategy as an optional alternative to the direct elimination solution method for the matrix equation approximating the partial differential equation of groundwater flow. FEWA also includes transient flow through confining leaky aquifers lying above and/or below the aquifer of interest. The model is verified against three simple cases to which analytical solutions are available. It is then demonstrated by two examples of how the model can be applied to heterogeneous and anisotropic aquifers with transient boundary conditions, time-dependent sources/sinks, and confining aquitards for a confined aquifer of variable thickness and for a free surface problem in an unconfined aquifer, respectively. 20 references, 25 figures, 8 tables

  15. Modeling Carbon Dioxide Storage in the Basal Aquifer of Canada

    Science.gov (United States)

    Huang, X.; Bandilla, K.; Celia, M. A.; Bachu, S.; Rebscher, D.; Zhou, Q.; Birkholzer, J. T.

    2012-12-01

    Reducing anthropogenic carbon dioxide (CO2) emissions into the atmosphere is a key challenge for society. Geological CO2 storage in deep saline aquifers is one of the most promising solutions to decrease carbon emissions. One such deep saline aquifer targeted for industrial-scale CO2 injection is the Basal Aquifer of Prairie Region in Canada and Northern Plains in the US. The aquifer stretches across three provinces (Alberta, Saskatchewan and Manitoba) and three states (Montana, North and South Dakota), and covers approximately 1,320,000 km2 (Figure 1). A large number of stationary CO2 sources lie within the foot print of the aquifer, and several CO2 injection projects are in the planning stage. In order for CO2 sequestration to be successful, the injected CO2 needs to stay isolated from the atmosphere for many centuries. Mathematical models are useful tools to assess the fate of both the injected CO2 and the resident brine. These models vary in complexity from fully three-dimensional multi-phase numerical reservoir simulators to simple semi-analytical solutions. In this presentation we compare a cascade of models ranging from single-phase semi-analytic solutions to multi-phase numerical simulators to determine the ability of each of these approaches to predict the pressure response in the injection formation. The majority of the models in this study are based on vertically-integrated governing equations; such models are computationally efficient, allow for reduced data input, and are broadly consistent with the flow physics. The petro-physical parameters and geometries used in this study are based on the geology of the Canadian section of the Basal Aquifer. Approximately ten injection sites are included in the model, with locations and injection rates based on planned injection operations. The predicted areas of review of the injection operations are used as a comparison metric among the different simulation approaches. Areal extent of the Basal Aquifer (*Source

  16. Reservoir Identification: Parameter Characterization or Feature Classification

    Science.gov (United States)

    Cao, J.

    2017-12-01

    The ultimate goal of oil and gas exploration is to find the oil or gas reservoirs with industrial mining value. Therefore, the core task of modern oil and gas exploration is to identify oil or gas reservoirs on the seismic profiles. Traditionally, the reservoir is identify by seismic inversion of a series of physical parameters such as porosity, saturation, permeability, formation pressure, and so on. Due to the heterogeneity of the geological medium, the approximation of the inversion model and the incompleteness and noisy of the data, the inversion results are highly uncertain and must be calibrated or corrected with well data. In areas where there are few wells or no well, reservoir identification based on seismic inversion is high-risk. Reservoir identification is essentially a classification issue. In the identification process, the underground rocks are divided into reservoirs with industrial mining value and host rocks with non-industrial mining value. In addition to the traditional physical parameters classification, the classification may be achieved using one or a few comprehensive features. By introducing the concept of seismic-print, we have developed a new reservoir identification method based on seismic-print analysis. Furthermore, we explore the possibility to use deep leaning to discover the seismic-print characteristics of oil and gas reservoirs. Preliminary experiments have shown that the deep learning of seismic data could distinguish gas reservoirs from host rocks. The combination of both seismic-print analysis and seismic deep learning is expected to be a more robust reservoir identification method. The work was supported by NSFC under grant No. 41430323 and No. U1562219, and the National Key Research and Development Program under Grant No. 2016YFC0601

  17. Reservoir engineering studies of the Gladys McCall geopressured-geothermal resource. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lea, C.M.; Lee, K.; Miller, M.A.

    1993-09-01

    Transient pressure analysis techniques have been used to evaluate the performance of the Gladys McCall geopressured-geothermal reservoir. A fault-controlled aquifer influx model has also been developed to account for pressure support observed during both reservoir depletion and recovery phases. The Gladys McCall No. 1 well was drilled and completed in the lower Miocene geopressured sandstones under the US Department of energy geopressured-geothermal research program. The well was shut in october 1987 after producing over 27 MMstb of brine and 676 MMscf gas since October 1983. Eight pressure transient tests were conducted in the well. Analysis of transient pressure data provided a quantitative evaluation of reservoir characteristics, including: (a) formation transmissibility and skin, (b) the size and possible shape of the main producing reservoir, (c) characteristics of the pressure support mechanism. The pressure behavior of 1983 Reservoir Limits Test (RLT) suggested that the Gladys McCall reservoir might have a long narrow shape with the well located off-center. An elongated numerical model developed accordingly was able to reproduce the pressure characteristics show in the test. During both the reservoir production and shut-in periods, pressure buildup tests indicated some degree of external pressure support. Aquifer recharging was believed to be the main source. Based on reservoir material-balance calculations, an aquifer influx model was derived from a conceptual model of water leakage through a partially sealing fault into the reservoir under steady-state conditions. Moreover, a match of the pressure history required that the conductivity of the fault be a function of the pressure difference between the supporting aquifer and the reservoir.

  18. Reservoir engineering studies of the Gladys McCall geopressured-geothermal resource; Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chen-Min; Less, K.; Miller, M.A.

    1994-01-01

    Transient pressure analysis techniques have been used to evaluate the performance of the Gladys McCall geopressured-geothermal reservoir. A fault-controlled aquifer influx model has also been developed to account for pressure support observed during both reservoir depletion and recovery phases. The Gladys McCall No. 1 well was drilled and completed in the lower Miocene geopressured sandstones under the US Department of Energy geopressured-geothermal research program. The well was shut in October 1987 after producing over 27 MMstb of brine and 676 MMscf gas since October 1983. Eight pressure transient tests were conducted in the well. Analysis of transient pressure data provided a quantitative evaluation of reservoir characteristics, including: (a) formation transmissibility and skin, (b) the size and possible shape of the main producing reservoir, and (c) characteristics of the pressure support mechanism. The pressure behavior of 1983 Reservoir Limits Test (RLT) suggested that the Gladys McCall reservoir might have a long narrow shape with the well located off-center. An elongated numerical model developed accordingly was able to reproduce the pressure characteristics shown in the test. During both the reservoir production and shut-in periods, pressure buildup tests indicated some degree of external pressure support. Aquifer recharging was believed to be the main source. Based on reservoir material-balance calculations, an aquifer influx model was derived from a conceptual model of water leakage through a partially sealing fault into the reservoir under steady-state conditions. Moreover, a match of the pressure history required that the conductivity of the fault be a function of the pressure difference between the supporting aquifer and the reservoir.

  19. Hydrochemical processes in a shallow coal seam gas aquifer and its overlying stream–alluvial system: implications for recharge and inter-aquifer connectivity

    International Nuclear Information System (INIS)

    Duvert, Clément; Raiber, Matthias; Owen, Daniel D.R.; Cendón, Dioni I.; Batiot-Guilhe, Christelle; Cox, Malcolm E.

    2015-01-01

    Highlights: • Major ions and isotopes used to study inter-aquifer mixing in a shallow CSG setting. • Considerable heterogeneity in the water composition of the coal-bearing aquifer. • Rapid recharge of the coal-bearing aquifer through highly fractured igneous rocks. • Potential mixing between the coal-bearing aquifer and downstream alluvial aquifer. • Need to consider the seasonal influences on inter-aquifer mixing in CSG settings. - Abstract: In areas of potential coal seam gas (CSG) development, understanding interactions between coal-bearing strata and adjacent aquifers and streams is of highest importance, particularly where CSG formations occur at shallow depth. This study tests a combination of hydrochemical and isotopic tracers to investigate the transient nature of hydrochemical processes, inter-aquifer mixing and recharge in a catchment where the coal-bearing aquifer is in direct contact with the alluvial aquifer and surface drainage network. A strong connection was observed between the main stream and underlying alluvium, marked by a similar evolution from fresh Ca–Mg–HCO 3 waters in the headwaters towards brackish Ca–Na–Cl composition near the outlet of the catchment, driven by evaporation and transpiration. In the coal-bearing aquifer, by contrast, considerable site-to-site variations were observed, although waters generally had a Na–HCO 3 –Cl facies and high residual alkalinity values. Increased salinity was controlled by several coexisting processes, including transpiration by plants, mineral weathering and possibly degradation of coal organic matter. Longer residence times and relatively enriched carbon isotopic signatures of the downstream alluvial waters were suggestive of potential interactions with the shallow coal-bearing aquifer. The examination of temporal variations in deuterium excess enabled detection of rapid recharge of the coal-bearing aquifer through highly fractured igneous rocks, particularly at the catchment

  20. Integrated reservoir assessment and characterization: Final report, October 1, 1985--September 30, 1988

    Energy Technology Data Exchange (ETDEWEB)

    Honarpour, M.; Szpakiewicz, M.; Sharma, B.; Chang, Ming-Ming; Schatzinger, R.; Jackson, S.; Tomutsa, L.; Maerefat, N.

    1989-05-01

    This report covers the development of a generic approach to reservoir characterization, the preliminary studies leading to the selection of an appropriate depositional system for detailed study, the application of outcrop studies to quantified reservoir characterization, and the construction of a quantified geological/engineering model used to screen the effects and scales of various geological heterogeneities within a reservoir. These heterogeneities result in large production/residual oil saturation contrasts over small distances. 36 refs., 124 figs., 38 tabs.

  1. Reservoir fisheries of Asia

    International Nuclear Information System (INIS)

    Silva, S.S. De.

    1990-01-01

    At a workshop on reservoir fisheries research, papers were presented on the limnology of reservoirs, the changes that follow impoundment, fisheries management and modelling, and fish culture techniques. Separate abstracts have been prepared for three papers from this workshop

  2. MULTIDISCIPLINARY IMAGING OF ROCK PROPERTIES IN CARBONATE RESERVOIRS FOR FLOW-UNIT TARGETING

    Energy Technology Data Exchange (ETDEWEB)

    Stephen C. Ruppel

    2005-02-01

    Despite declining production rates, existing reservoirs in the US contain large quantities of remaining oil and gas that constitute a huge target for improved diagnosis and imaging of reservoir properties. The resource target is especially large in carbonate reservoirs, where conventional data and methodologies are normally insufficient to resolve critical scales of reservoir heterogeneity. The objectives of the research described in this report were to develop and test such methodologies for improved imaging, measurement, modeling, and prediction of reservoir properties in carbonate hydrocarbon reservoirs. The focus of the study is the Permian-age Fullerton Clear Fork reservoir of the Permian Basin of West Texas. This reservoir is an especially appropriate choice considering (a) the Permian Basin is the largest oil-bearing basin in the US, and (b) as a play, Clear Fork reservoirs have exhibited the lowest recovery efficiencies of all carbonate reservoirs in the Permian Basin.

  3. Geothermal reservoirs. Position of slotted section of the tube casing

    International Nuclear Information System (INIS)

    Carotenuto, A.; Vanoli, L.; Casarosa, C.

    1999-01-01

    In the present work the authors have verified the influence of the position of slotted section casing on heat rate drawn by plants for exploitation of geothermal reservoirs that use heat exchangers placed at the bottom of the well (DHE). This study have been done modelling numerically the aquifer, by means of finite element method, evaluating the heat rate drawn by the heat exchanger at different position of the slotted section of the tube casing. Numerical calculations have allowed to show the influence of the main characteristics of the aquifer and of the main characteristics of the aquifer and of the plant on design of the slotted section of the tube casing. In particular, the authors have studied the influence of i) equivalent conductivity and permeability of the aquifer, ii) mass flow rate and the inlet and outlet aquifer temperature difference in the well, iii) the ratio between the length of the slotted section and the thickness of the geothermal layer, varying the position of the slotted section of the tube casing in the aquifer [it

  4. Large reservoirs: Chapter 17

    Science.gov (United States)

    Miranda, Leandro E.; Bettoli, Phillip William

    2010-01-01

    Large impoundments, defined as those with surface area of 200 ha or greater, are relatively new aquatic ecosystems in the global landscape. They represent important economic and environmental resources that provide benefits such as flood control, hydropower generation, navigation, water supply, commercial and recreational fisheries, and various other recreational and esthetic values. Construction of large impoundments was initially driven by economic needs, and ecological consequences received little consideration. However, in recent decades environmental issues have come to the forefront. In the closing decades of the 20th century societal values began to shift, especially in the developed world. Society is no longer willing to accept environmental damage as an inevitable consequence of human development, and it is now recognized that continued environmental degradation is unsustainable. Consequently, construction of large reservoirs has virtually stopped in North America. Nevertheless, in other parts of the world construction of large reservoirs continues. The emergence of systematic reservoir management in the early 20th century was guided by concepts developed for natural lakes (Miranda 1996). However, we now recognize that reservoirs are different and that reservoirs are not independent aquatic systems inasmuch as they are connected to upstream rivers and streams, the downstream river, other reservoirs in the basin, and the watershed. Reservoir systems exhibit longitudinal patterns both within and among reservoirs. Reservoirs are typically arranged sequentially as elements of an interacting network, filter water collected throughout their watersheds, and form a mosaic of predictable patterns. Traditional approaches to fisheries management such as stocking, regulating harvest, and in-lake habitat management do not always produce desired effects in reservoirs. As a result, managers may expend resources with little benefit to either fish or fishing. Some locally

  5. Modeling of fault activation and seismicity by injection directly into a fault zone associated with hydraulic fracturing of shale-gas reservoirs

    Science.gov (United States)

    LBNL, in consultation with the EPA, expanded upon a previous study by injecting directly into a 3D representation of a hypothetical fault zone located in the geologic units between the shale-gas reservoir and the drinking water aquifer.

  6. Combining Deterministic structures and stochastic heterogeneity for transport modeling

    Science.gov (United States)

    Zech, Alraune; Attinger, Sabine; Dietrich, Peter; Teutsch, Georg

    2017-04-01

    Contaminant transport in highly heterogeneous aquifers is extremely challenging and subject of current scientific debate. Tracer plumes often show non-symmetric but highly skewed plume shapes. Predicting such transport behavior using the classical advection-dispersion-equation (ADE) in combination with a stochastic description of aquifer properties requires a dense measurement network. This is in contrast to the available information for most aquifers. A new conceptual aquifer structure model is presented which combines large-scale deterministic information and the stochastic approach for incorporating sub-scale heterogeneity. The conceptual model is designed to allow for a goal-oriented, site specific transport analysis making use of as few data as possible. Thereby the basic idea is to reproduce highly skewed tracer plumes in heterogeneous media by incorporating deterministic contrasts and effects of connectivity instead of using unimodal heterogeneous models with high variances. The conceptual model consists of deterministic blocks of mean hydraulic conductivity which might be measured by pumping tests indicating values differing in orders of magnitudes. A sub-scale heterogeneity is introduced within every block. This heterogeneity can be modeled as bimodal or log-normal distributed. The impact of input parameters, structure and conductivity contrasts is investigated in a systematic manor. Furthermore, some first successful implementation of the model was achieved for the well known MADE site.

  7. Heterogeneous reactors

    International Nuclear Information System (INIS)

    Moura Neto, C. de; Nair, R.P.K.

    1979-08-01

    The microscopic study of a cell is meant for the determination of the infinite multiplication factor of the cell, which is given by the four factor formula: K(infinite) = n(epsilon)pf. The analysis of an homogeneous reactor is similar to that of an heterogeneous reactor, but each factor of the four factor formula can not be calculated by the formulas developed in the case of an homogeneous reactor. A great number of methods was developed for the calculation of heterogeneous reactors and some of them are discussed. (Author) [pt

  8. Energy R and D. Geothermal energy and underground reservoirs; R et D energie. Geothermie et reservoirs souterrains

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    Geothermal energy appears as a viable economic alternative among the different renewable energy sources. The French bureau of geological and mining researches (BRGM) is involved in several research and development programs in the domain of geothermal energy and underground reservoirs. This document presents the content of 5 programs: the deep hot dry rock system of Soultz-sous-Forets (construction and testing of the scientific pilot, modeling of the reservoir structure), the development of low and high enthalpy geothermal energy in the French West Indies, the comparison of the geothermal development success of Bouillante (Guadeloupe, French West Indies) with the check of the geothermal development of Nyssiros (Greece) and Pantelleria (Italy), the development of the high enthalpy geothermal potentialities of Reunion Island, and the underground storage of CO{sub 2} emissions in geologic formations (deep aquifers, geothermal reservoirs, abandoned mines or oil reservoirs). (J.S.)

  9. Application of integrated reservoir management and reservoir characterization to optimize infill drilling. Annual report, June 13, 1994--June 12, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Pande, P.K.

    1996-11-01

    This project has used a multi-disciplinary approach employing geology, geophysics, and engineering to conduct advanced reservoir characterization and management activities to design and implement an optimized infill drilling program at the North Robertson (Clearfork) Unit in Gaines County, Texas. The activities during the first Budget Period have consisted of developing an integrated reservoir description from geological, engineering, and geostatistical studies, and using this description for reservoir flow simulation. Specific reservoir management activities are being identified and tested. The geologically targeted infill drilling program will be implemented using the results of this work. A significant contribution of this project is to demonstrate the use of cost-effective reservoir characterization and management tools that will be helpful to both independent and major operators for the optimal development of heterogeneous, low permeability shallow-shelf carbonate (SSC) reservoirs. The techniques that are outlined for the formulation of an integrated reservoir description apply to all oil and gas reservoirs, but are specifically tailored for use in the heterogeneous, low permeability carbonate reservoirs of West Texas.

  10. Thermophysical behavior of St. Peter sandstone: application to compressed air energy storage in an aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Erikson, R.L.

    1983-12-01

    The long-term stability of a sandstone reservoir is of primary importance to the success of compressed air energy storage (CAES) in aquifers. The purpose of this study was to: develop experimental techniques for the operation of the CAES Porous Media Flow Loop (PMFL), an apparatus designed to study the stability of porous media in subsurface geologic environments, conduct experiments in the PMFL designed to determine the effects of temperature, stress, and humidity on the stability of candidate CAES reservoir materials, provide support for the CAES field demonstration project in Pittsfield, Illinois, by characterizing the thermophysical stability of Pittsfield reservoir sandstone under simulated field conditions.

  11. Stream, Lake, and Reservoir Management.

    Science.gov (United States)

    Dai, Jingjing; Mei, Ying; Chang, Chein-Chi

    2017-10-01

    This review on stream, lake, and reservoir management covers selected 2016 publications on the focus of the following sections: Stream, lake, and reservoir management • Water quality of stream, lake, and reservoirReservoir operations • Models of stream, lake, and reservoir • Remediation and restoration of stream, lake, and reservoir • Biota of stream, lake, and reservoir • Climate effect of stream, lake, and reservoir.

  12. EPA Region 1 Sole Source Aquifers

    Data.gov (United States)

    U.S. Environmental Protection Agency — This coverage contains boundaries of EPA-approved sole source aquifers. Sole source aquifers are defined as an aquifer designated as the sole or principal source of...

  13. Status of Wheeler Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    1990-09-01

    This is one in a series of status reports prepared by the Tennessee Valley Authority (TVA) for those interested in the conditions of TVA reservoirs. This overview of Wheeler Reservoir summarizes reservoir purposes and operation, reservoir and watershed characteristics, reservoir uses and use impairments, and water quality and aquatic biological conditions. The information presented here is from the most recent reports, publications, and original data available. If no recent data were available, historical data were summarized. If data were completely lacking, environmental professionals with special knowledge of the resource were interviewed. 12 refs., 2 figs.

  14. Facies sedimentology, mineralogy and genetic stratigraphy of the lower-Lias silici-clastic reservoirs of Cere-La-Ronde; Sedimentologie de facies, mineralogie et stratigraphie genetique des reservoirs silicoclastiques du Lias inferieur de Cere-La-Ronde

    Energy Technology Data Exchange (ETDEWEB)

    Geiller, M.

    1997-11-21

    Some sandstone reservoirs in the South West of the Parisian Basin (Sologne) are used for gas storage in the underground aquifer by GDF. The study aims to reconstruct the geometry of these reservoirs and to establish the factors controlling their deposition in the Sologne basin during Rhaetian and Hettangian times. This study combines palynological, sedimentological, mineralogical and sequential analyses. It is applied to channel deposits as well as to flood-plain and over-bank deposits which are rarely considered. The formations are deposited in a continental transgressive context associated to a decreasing subsidence. The different depositional environments varied from the alluvial fan to the coastal plain with different intermediate alluvial plains. They get organized in three depositional profiles which are emphasized by hydrodynamic discontinuities due to irreversible modifications in depositional conditions. The clayey associations change with each depositional profile according to detrital source modifications. They characterize discontinuities due to geodynamic events affecting the Sologne basin (depositional profile changes, pedogenesis). In this continental context, the genetic sequences record a cycle of variation of the river longitudinal profile slope. They determine the sediments geometry which results from the relative sea-level variations. Local tectonics creates an heterogenous subsidence and consequently controls the distribution of the sediments. During tectonic instability periods, the subsiding areas migrate while they do not during tectonic stability periods. The latter end with irreversible change in depositional profile. (author) 135 refs.

  15. Hydrogeologic characterization of a fractured granitic rock aquifer, Raymond, California

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Andrew J.B. [Univ. of California, Berkeley, CA (United States)

    1993-10-01

    The hydrogeologic properties of a shallow, fractured granitic rock aquifer in the foothills of the Sierra Nevada, California were investigated via the analysis of borehole geophysical logs and pumping tests. The drawdowns produced during these tests are not indicative of any simple conceptual aquifer model, and borehole logs show that the granite is intensely fractured. These observations are suggestive of a complex fracture-flow geometry which is extremely difficult to decipher. However, through the measurement of orientations of individual subsurface fractures from acoustic televiewer logs, and correlation between particular fractures and electrical resistivity and thermal-pulse flowmeter logs, it was found that the aquifer is, in general, comprised of two subhorizontal and nearly parallel zones of unloading fractures. Downhole flowmeter measurements taken in several wells provide further evidence for the inferred dual-layer structure of the aquifer, as well as yield quantitative measures of the contribution of flow from each zone. Analysis of drawdowns in pumped wells reveals that there are zones of relatively high transmissivity immediately around them. It was found that these properties, as well as a nearby zone of lower transmissivity, can account for their observed drawdowns. A numerical model was constructed to test whether these major heterogeneities could also account for the drawdowns in observation wells. This stepwise analysis of both the geophysical and hydrological data resulted in the formulation of a conceptual model of the aquifer which is consistent with observations, and which can account for its behavior when subjected to pumping.

  16. Simulating oil recovery during CO{sub 2} sequestration into a mature oil reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Pamukcu, Y.Z. [Oklahoma Univ., Norman, OK (United States); Gumrah, F. [Middle East Technical Univ., Ankara (Turkey)

    2007-07-01

    The advantages of sequestering carbon dioxide (CO{sub 2}) into depleted oil reservoirs were discussed with particular reference to the Kartaltepe Field in southeast Turkey. Geologic sequestration is gaining interest as an option to dispose large amount of CO{sub 2} safely and economically for long-term periods. This emerging technology to reduce large amounts of CO{sub 2} released into the atmosphere involves the capture of CO{sub 2} from hydrocarbon emissions, transportation of compressed CO{sub 2} from the source to the field, and injection and storage of CO{sub 2} into the subsurface. While CO{sub 2} injection into oil reservoirs has been in practice for enhanced oil recovery (EOR) purposes for more than 35 years, this paper focused on how to maximize oil recovery with the minimum quantity of CO{sub 2} and sequestering the maximum amount of CO{sub 2}. The Kartaltepe Field which has been in production since 1982, consists of alternating layers of sands and shales deposited in deltaic and marine carbonates to form a faulted anticline structure extending over an area of 2.70 km by 0.75 km. The light crude is produced from a carbonate formation at an average depth of 1930 m to 1950 m. The primary drive mechanism is water drive. The reservoir is a heterogeneous reef composed of two distinct carbonate formations. The upper formation is limestone with an average porosity of 5 per cent and average permeability of 0.06 md. The lower formation is dolomite with an average porosity of 25 per cent, and average permeability of 60 md. The reservoir shape is anticline, and it is bounded by faults and underlain by an aquifer. Reservoir rock and fluid data were evaluated and merged into CMG/STARS simulator. History matching was done with production data to verify the results of the simulator with field data. Once a good match was obtained, different scenarios were simulated. The results showed that CO{sub 2} injection can increase oil recovery. However, it was determined that

  17. Advective transport in heterogeneous aquifers: Are proxy models predictive?

    Science.gov (United States)

    Fiori, A.; Zarlenga, A.; Gotovac, H.; Jankovic, I.; Volpi, E.; Cvetkovic, V.; Dagan, G.

    2015-12-01

    We examine the prediction capability of two approximate models (Multi-Rate Mass Transfer (MRMT) and Continuous Time Random Walk (CTRW)) of non-Fickian transport, by comparison with accurate 2-D and 3-D numerical simulations. Both nonlocal in time approaches circumvent the need to solve the flow and transport equations by using proxy models to advection, providing the breakthrough curves (BTC) at control planes at any x, depending on a vector of five unknown parameters. Although underlain by different mechanisms, the two models have an identical structure in the Laplace Transform domain and have the Markovian property of independent transitions. We show that also the numerical BTCs enjoy the Markovian property. Following the procedure recommended in the literature, along a practitioner perspective, we first calibrate the parameters values by a best fit with the numerical BTC at a control plane at x1, close to the injection plane, and subsequently use it for prediction at further control planes for a few values of σY2≤8. Due to a similar structure and Markovian property, the two methods perform equally well in matching the numerical BTC. The identified parameters are generally not unique, making their identification somewhat arbitrary. The inverse Gaussian model and the recently developed Multi-Indicator Model (MIM), which does not require any fitting as it relates the BTC to the permeability structure, are also discussed. The application of the proxy models for prediction requires carrying out transport field tests of large plumes for a long duration.

  18. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SANANDRES RESERVOIR

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2003-01-15

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO{sub 2}) stimulation treatments; (6) Hydraulic fracturing design and monitoring; (7) Mobility control agents.

  19. Groundwater Dynamics and Export from Active Layer Aquifers Overlying Permafrost

    Science.gov (United States)

    O'Connor, M.; Cardenas, M. B.; Neilson, B. T.; Nicholaides, K. D.; Kling, G. W.

    2017-12-01

    Vast reservoirs of organic matter become accessible each summer when Arctic soils thaw. Groundwater transports this organic matter into streams, where it can be respired into CO2. Many have speculated that groundwater volumes might increase as the climate warms; however, such speculation requires a robust characterization of the hydraulic properties and geometries of the temporary aquifer through which this groundwater flows. Here we present observations and model results describing how groundwater fluxes evolve seasonally and spatially in the temporary `aquifers' underlying the Alaskan North Slope. Saturated and unsaturated permeability and porosity exhibited extreme vertical variability but maintained lateral consistency at different depths. Aquifer saturated thicknesses were controlled by sub-meter topographic features rather than regional topographic gradients. Such variation creates a fluctuating ice table, developing groundwater flow paths that mimic surface topography and skew residence time distributions. We used observed hydraulic properties and aquifer geometries to calculate how groundwater export evolves during a wet year between early and late summer. Despite a deepening of the saturated zone, resulting in large decreases in permeability and groundwater velocity, groundwater fluxes were larger in August than June because the saturated zone expanded sufficiently. However, historical data suggests the opposite could be true under dry conditions where minor fluctuations in the water table elevation could switch the active layer from an effective to ineffective transmitter of groundwater. The significant effects exerted by microtopography and soil property variability on groundwater flow underscore the need for them to be accurately represented within any future groundwater flow predictions.

  20. Optimal Energy Extraction From a Hot Water Geothermal Reservoir

    Science.gov (United States)

    Golabi, Kamal; Scherer, Charles R.; Tsang, Chin Fu; Mozumder, Sashi

    1981-01-01

    An analytical decision model is presented for determining optimal energy extraction rates from hot water geothermal reservoirs when cooled brine is reinjected into the hot water aquifer. This applied economic management model computes the optimal fluid pumping rate and reinjection temperature and the project (reservoir) life consistent with maximum present worth of the net revenues from sales of energy for space heating. The real value of product energy is assumed to increase with time, as is the cost of energy used in pumping the aquifer. The economic model is implemented by using a hydrothermal model that relates hydraulic pumping rate to the quality (temperature) of remaining heat energy in the aquifer. The results of a numerical application to space heating show that profit-maximizing extraction rate increases with interest (discount) rate and decreases as the rate of rise of real energy value increases. The economic life of the reservoir generally varies inversely with extraction rate. Results were shown to be sensitive to permeability, initial equilibrium temperature, well cost, and well life.

  1. Efficiency of joint use of MRS and VES to characterize coastal aquifer in Myanmar

    Science.gov (United States)

    Vouillamoz, J. M.; Chatenoux, B.; Mathieu, F.; Baltassat, J. M.; Legchenko, A.

    2007-02-01

    The productivity and the water quality of coastal aquifers can be highly heterogeneous in a complex environment. The characterization of these aquifers can be improved by hydrogeological and complementary geophysical surveys. Such an integrated approach is developed in a non-consolidated coastal aquifer in Myanmar (previously named Burma). A preliminary hydrogeological survey is conducted to know better the targeted aquifers. Then, 25 sites are selected to characterize aquifers through borehole drillings and pumping tests implementation. In the same sites, magnetic resonance soundings (MRS) and vertical electrical soundings (VES) are carried out. Geophysical results are compared to hydrogeological data, and geophysical parameters are used to characterize aquifers using conversion equations. Finally, combining the analysis of technical and economical impacts of geophysics, a methodology is proposed to characterize non-consolidated coastal aquifers. Depth and thickness of saturated zone is determined by means of MRS in 68% of the sites (evaluated with 34 soundings). The average accuracy of confined storativity estimated with MRS is ± 6% (evaluated over 7 pumping tests) whereas the average accuracy of transmissivity estimation with MRS is ± 45% (evaluated using 15 pumping tests). To reduce uncertainty in VES interpretation, the aquifer geometry estimated with MRS is used as a fixed parameter in VES inversion. The accuracy of groundwater electrical conductivity evaluation from 15 VES is enough to estimate the risk of water salinity. In addition, the maximum depth of penetration of the MRS depends on the rocks' electrical resistivity and is between 20 and 80 m at the study area.

  2. The contribution of environmental isotopes to studies of large aquifers in Morocco

    International Nuclear Information System (INIS)

    Kabbaj, A.; Zeryouhi, I.; Carlier, Ph.

    1979-01-01

    The geochemistry of environmental isotopes has been used for the study of various aquifers in Morocco, some of which are large, such as the Charf el Akab in the Tangiers area, the Oum er Rbia basin and the Turonian aquifer of the Tadla, the free groundwater of the Quaternary lacustrine limestones of the Sais Plain and the Lias limestone aquifer. These isotope studies take hydrogeochemical data into account and have made it possible to determine the conditions of recharge of the aquifers, to distinguish waters of different origin from the Atlas Mountains or from the Phosphate Plateau in the Tadla Basin and the Sais plain, to estimate the recharge of one aquifer by another - for example groundwater of the Lias limestones passing via the folds of the Sais Plain into the lacustrine limestone aquifer - and to test the homogeneity or heterogeneity of these aquifers and their tightness (e.g. the Turonian aquifer of the Tadla and the special case of the Charf el Akab in relation to the marine environment). Altogether, these results made it possible to test the value of the techniques used and to specify the general conditions in which they can profitably be used. (author)

  3. Reservoir characterization and enhanced oil recovery research

    Energy Technology Data Exchange (ETDEWEB)

    Lake, L.W.; Pope, G.A.; Schechter, R.S.

    1992-03-01

    The research in this annual report falls into three tasks each dealing with a different aspect of enhanced oil recovery. The first task strives to develop procedures for accurately modeling reservoirs for use as input to numerical simulation flow models. This action describes how we have used a detail characterization of an outcrop to provide insights into what features are important to fluid flow modeling. The second task deals with scaling-up and modeling chemical and solvent EOR processes. In a sense this task is the natural extension of task 1 and, in fact, one of the subtasks uses many of the same statistical procedures for insight into the effects of viscous fingering and heterogeneity. The final task involves surfactants and their interactions with carbon dioxide and reservoir minerals. This research deals primarily with phenomena observed when aqueous surfactant solutions are injected into oil reservoirs.

  4. Design and reliability engineering of aquifer CO{sub 2} disposal in Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Hachiya, A.; Frimpong, S. [Alberta Univ., Edmonton, AB (Canada)

    2000-07-01

    Carbon dioxide (CO{sub 2}) storage or disposal options have been proposed as a means by which to deal with long-term CO{sub 2} emissions in Alberta. The option includes CO{sub 2} storage or disposal into geological sinks such as an aquifer, depleted oil reservoir, coal bed or the ocean. Currently, CO{sub 2} aquifer disposal is the most feasible option. Studies have shown that an appropriate Glauconitic aquifer exists in the Alberta Basin. A detailed review of the geology and stability of the land aquifers in the Alberta Basin has been carried out and the phase dynamics and the trapping mechanisms of CO{sub 2} in aquifers was examined along with the porosity, permeability and fracture pressure properties of the host aquifers. A model was developed which showed the technical feasibility of CO{sub 2} disposal systems. The model was validated using flue gas from the 546 MW Wabamun coal-fired power plant in Alberta. Analytical designs were created for the liquefaction-transportation-injection networks based on the reaction kinetics and phase dynamics of CO{sub 2} under various temperature and pressure conditions. Results shows that CO{sub 2} can be safely trapped in the aquifers by chemical and hydrodynamic trapping over a long geological period. 9 refs., 2 tabs., 4 figs.

  5. The effect of soil heterogeneity on ATES performance

    Science.gov (United States)

    Sommer, W.; Rijnaarts, H.; Grotenhuis, T.; van Gaans, P.

    2012-04-01

    Due to an increasing demand for sustainable energy, application of Aquifer Thermal Energy Storage (ATES) is growing rapidly. Large-scale application of ATES is limited by the space that is available in the subsurface. Especially in urban areas, suboptimal performance is expected due to thermal interference between individual wells of a single system, or interference with other ATES systems or groundwater abstractions. To avoid thermal interference there are guidelines on well spacing. However, these guidelines, and also design calculations, are based on the assumption of a homogeneous subsurface, while studies report a standard deviation in logpermeability of 1 to 2 for unconsolidated aquifers (Gelhar, 1993). Such heterogeneity may create preferential pathways, reducing ATES performance due to increased advective heat loss or interference between ATES wells. The role of hydraulic heterogeneity of the subsurface related to ATES performance has received little attention in literature. Previous research shows that even small amounts of heterogeneity can result in considerable uncertainty in the distribution of thermal energy in the subsurface and an increased radius of influence (Ferguson, 2007). This is supported by subsurface temperature measurements around ATES wells, which suggest heterogeneity gives rise to preferential pathways and short-circuiting between ATES wells (Bridger and Allen, 2010). Using 3-dimensional stochastic heat transport modeling, we quantified the influence of heterogeneity on the performance of a doublet well energy storage system. The following key parameters are varied to study their influence on thermal recovery and thermal balance: 1) regional flow velocity, 2) distance between wells and 3) characteristics of the heterogeneity. Results show that heterogeneity at the scale of a doublet ATES system introduces an uncertainty up to 18% in expected thermal recovery. The uncertainty increases with decreasing distance between ATES wells. The

  6. Reduced-Order Model for the Geochemical Impacts of Carbon Dioxide, Brine and Trace Metal Leakage into an Unconfined, Oxidizing Carbonate Aquifer, Version 2.1

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, Diana H.

    2013-03-31

    The National Risk Assessment Partnership (NRAP) consists of 5 U.S DOE national laboratories collaborating to develop a framework for predicting the risks associated with carbon sequestration. The approach taken by NRAP is to divide the system into components, including injection target reservoirs, wellbores, natural pathways including faults and fractures, groundwater and the atmosphere. Next, develop a detailed, physics and chemistry-based model of each component. Using the results of the detailed models, develop efficient, simplified models, termed reduced order models (ROM) for each component. Finally, integrate the component ROMs into a system model that calculates risk profiles for the site. This report details the development of the Groundwater Geochemistry ROM for the Edwards Aquifer at PNNL. The Groundwater Geochemistry ROM for the Edwards Aquifer uses a Wellbore Leakage ROM developed at LANL as input. The detailed model, using the STOMP simulator, covers a 5x8 km area of the Edwards Aquifer near San Antonio, Texas. The model includes heterogeneous hydraulic properties, and equilibrium, kinetic and sorption reactions between groundwater, leaked CO2 gas, brine, and the aquifer carbonate and clay minerals. Latin Hypercube sampling was used to generate 1024 samples of input parameters. For each of these input samples, the STOMP simulator was used to predict the flux of CO2 to the atmosphere, and the volume, length and width of the aquifer where pH was less than the MCL standard, and TDS, arsenic, cadmium and lead exceeded MCL standards. In order to decouple the Wellbore Leakage ROM from the Groundwater Geochemistry ROM, the response surface was transformed to replace Wellbore Leakage ROM input parameters with instantaneous and cumulative CO2 and brine leakage rates. The most sensitive parameters proved to be the CO2 and brine leakage rates from the well, with equilibrium coefficients for calcite and dolomite, as well as the number of illite and kaolinite

  7. 3D modeling of carbonates petro-acoustic heterogeneities

    Science.gov (United States)

    Baden, Dawin; Guglielmi, Yves; Saracco, Ginette; Marié, Lionel; Viseur, Sophie

    2015-04-01

    Characterizing carbonate reservoirs heterogeneity is a challenging issue for Oil & Gas Industry, CO2 sequestration and all kinds of fluid manipulations in natural reservoirs, due to the significant impact of heterogeneities on fluid flow and storage within the reservoir. Although large scale (> meter) heterogeneities such as layers petrophysical contrasts are well addressed by computing facies-based models, low scale (geo-modeler. This method successfully allowed detecting and imaging in three dimensions differential diagenesis effects characterized by the occurrence of decimeter-scale diagenetic horizons in samples assumed to be homogeneous and/or different diagenetic sequences between shells filling and the packing matrix. We then discuss how small interfaces such as cracks, stylolithes and laminations which are also imaged may have guided these differential effects, considering that understanding the processes may be taken as an analogue to actual fluid drainage complexity in deep carbonate reservoir.

  8. Dump-flooding to maximize recovery in a volumetric reservoir; A auto-injecao como solucao para maximizacao do fator de recuperacao em reservatorio volumetrico

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Rodrigo de Carvalho; Gasperi, Andre de; Lima, Saulo de Tarso Cerqueira; Camara, Paulo Sergio [PETROBRAS S.A. Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The dump-flooding consists of the communication of a more pressurized aquifer with a less pressurized oil reservoir. The basic condition for the application of this method is the presence of a geological favorable condition, in other words, a depleted oil reservoir near to an aquifer with appropriate characteristics of pressure, volume and transmissibility. The reservoir EN100 of the Albacora Field, Campos Basin, Brazil, started production in May 2004. In September 2005, this reservoir had a depletion of around 130 kg f/c m2, and its production had fallen from 1400 m3/d to about 800 m3/d. The reservoir EN200, which started production in May 2002, was presenting a stabilized depletion of only 30 kg f/c m2 due to its connection to a large aquifer. Considering this behavior it was proposed a dump-flooding project, drilling a new well to connect the aquifer of the EN200 reservoir to the EN100 reservoir. After the beginning of the dump-flooding, in June 2007, the oil rate of the EN100 reservoir rose quickly, reaching again values near to 1400 m3/d. The introduction of the dump-flooding project allowed the predicted ultimate recovery factor to increase from 9,6% to about 40%. (author)

  9. SILTATION IN RESERVOIRS

    African Journals Online (AJOL)

    Calls have been made to the government through various media to assist its populace in combating this nagging problem. It was concluded that sediment maximum accumulation is experienced in reservoir during the periods of maximum flow. Keywords: reservoir model, siltation, sediment, catchment, sediment transport. 1.

  10. Dynamic reservoir well interaction

    NARCIS (Netherlands)

    Sturm, W.L.; Belfroid, S.P.C.; Wolfswinkel, O. van; Peters, M.C.A.M.; Verhelst, F.J.P.C.M.

    2004-01-01

    In order to develop smart well control systems for unstable oil wells, realistic modeling of the dynamics of the well is essential. Most dynamic well models use a semi-steady state inflow model to describe the inflow of oil and gas from the reservoir. On the other hand, reservoir models use steady

  11. Reservoir Engineering Management Program

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J.H.; Schwarz, W.J.

    1977-12-14

    The Reservoir Engineering Management Program being conducted at Lawrence Berkeley Laboratory includes two major tasks: 1) the continuation of support to geothermal reservoir engineering related work, started under the NSF-RANN program and transferred to ERDA at the time of its formation; 2) the development and subsequent implementation of a broad plan for support of research in topics related to the exploitation of geothermal reservoirs. This plan is now known as the GREMP plan. Both the NSF-RANN legacies and GREMP are in direct support of the DOE/DGE mission in general and the goals of the Resource and Technology/Resource Exploitation and Assessment Branch in particular. These goals are to determine the magnitude and distribution of geothermal resources and reduce risk in their exploitation through improved understanding of generically different reservoir types. These goals are to be accomplished by: 1) the creation of a large data base about geothermal reservoirs, 2) improved tools and methods for gathering data on geothermal reservoirs, and 3) modeling of reservoirs and utilization options. The NSF legacies are more research and training oriented, and the GREMP is geared primarily to the practical development of the geothermal reservoirs. 2 tabs., 3 figs.

  12. Groundwater vulnerability mapping in Guadalajara aquifers system (Western Mexico)

    Science.gov (United States)

    Rizo-Decelis, L. David; Marín, Ana I.; Andreo, Bartolomé

    2016-04-01

    Groundwater vulnerability mapping is a practical tool to implement strategies for land-use planning and sustainable socioeconomic development coherent with groundwater protection. The objective of vulnerability mapping is to identify the most vulnerable zones of catchment areas and to provide criteria for protecting the groundwater used for drinking water supply. The delineation of protection zones in fractured aquifers is a challenging task due to the heterogeneity and anisotropy of hydraulic conductivities, which makes difficult prediction of groundwater flow organization and flow velocities. Different methods of intrinsic groundwater vulnerability mapping were applied in the Atemajac-Toluquilla groundwater body, an aquifers system that covers around 1300 km2. The aquifer supplies the 30% of urban water resources of the metropolitan area of Guadalajara (Mexico), where over 4.6 million people reside. Study area is located in a complex neotectonic active volcanic region in the Santiago River Basin (Western Mexico), which influences the aquifer system underneath the city. Previous works have defined the flow dynamics and identified the origin of recharge. In addition, the mixture of fresh groundwater with hydrothermal and polluted waters have been estimated. Two main aquifers compose the multilayer system. The upper aquifer is unconfined and consists of sediments and pyroclastic materials. Recharge of this aquifer comes from rainwater and ascending vertical fluids from the lower aquifer. The lower aquifer consists of fractured basalts of Pliocene age. Formerly, the main water source has been the upper unit, which is a porous and unconsolidated unit, which acts as a semi-isotropic aquifer. Intense groundwater usage has resulted in lowering the water table in the upper aquifer. Therefore, the current groundwater extraction is carried out from the deeper aquifer and underlying bedrock units, where fracture flow predominates. Pollution indicators have been reported in

  13. Are Geotehrmal Reservoirs Stressed Out?

    Science.gov (United States)

    Davatzes, N. C.; Laboso, R. C.; Layland-Bachmann, C. E.; Feigl, K. L.; Foxall, W.; Tabrez, A. R.; Mellors, R. J.; Templeton, D. C.; Akerley, J.

    2017-12-01

    Crustal permeability can be strongly influenced by developing connected networks of open fractures. However, the detailed evolution of a fracture network, its extent, and the persistence of fracture porosity are difficult to analyze. Even in fault-hosted geothermal systems, where heat is brought to the surface from depth along a fault, hydrothermal flow is heterogeneously distributed. This is presumably due to variations in fracture density, connectivity, and attitude, as well as variations in fracture permeability caused by sealing of fractures by precipitated cements or compaction. At the Brady Geothermal field in Nevada, we test the relationship between the modeled local stress state perturbed by dislocations representing fault slip or volume changes in the geothermal reservoir inferred from surface deformation measured by InSAR and the location of successful geothermal wells, hydrothermal activity, and seismicity. We postulate that permeability is favored in volumes that experience positive Coulomb stress changes and reduced compression, which together promote high densities of dilatant fractures. Conversely, permeability can be inhibited in locations where Coulomb stress is reduced, compression promotes compaction, or where the faults are poorly oriented in the stress field and consequently slip infrequently. Over geologic time scales spanning the development of the fault system, these local stress states are strongly influenced by the geometry of the fault network relative to the remote stress driving slip. At shorter time scales, changes in fluid pressure within the fracture network constituting the reservoir cause elastic dilations and contractions. We integrate: (1) direct observations of stress state and fractures in boreholes and the mapped geometry of the fault network; (2) evidence of permeability from surface hydrothermal features, production/injection wells and surface deformations related to pumping history; and (3) seismicity to test the

  14. Modelling studies for influence factors of gas bubble in compressed air energy storage in aquifers

    International Nuclear Information System (INIS)

    Guo, Chaobin; Zhang, Keni; Li, Cai; Wang, Xiaoyu

    2016-01-01

    CAES (Compressed air energy storage) is credited with its potential ability for large-scale energy storage. Generally, it is more convenient using deep aquifers than employing underground caverns for energy storage, because of extensive presence of aquifers. During the first stage in a typical process of CAESA (compressed air energy storage in aquifers), a large amount of compressed air is injected into the target aquifer to develop an initial space (a gas bubble) for energy storage. In this study, numerical simulations were conducted to investigate the influence of aquifer's permeability, geological structure and operation parameters on the formation of gas bubble and the sustainability for the later cycling operation. The SCT (system cycle times) was designed as a parameter to evaluate the reservoir performance and the effect of operation parameters. Simulation results for pressure and gas saturation results of basic model confirm the feasibility of compressed air energy storage in aquifers. The results of different permeability cases show that, for a certain scale of CAESA system, there is an optimum permeability range for a candidate aquifer. An aquifer within this permeability range will not only satisfy the injectivity requirement but also have the best energy efficiency. Structural impact analysis indicates that the anticline structure has the best performance to hold the bubble under the same daily cycling schedule with the same initial injected air mass. In addition, our results indicate that the SCT shows a logarithmic growth as the injected air mass increase. During the formation of gas bubble, compressed air should be injected into aquifers with moderate rate and the injection can be done in several stages with different injection rate to avoid onset pressure. - Highlights: • Impact of permeability, geological structure, operation parameters was investigated. • With certain air production rate, an optimum permeability exists for performance.

  15. Geochemical detection of carbon dioxide in dilute aquifers

    Directory of Open Access Journals (Sweden)

    Aines Roger

    2009-03-01

    Full Text Available Abstract Background Carbon storage in deep saline reservoirs has the potential to lower the amount of CO2 emitted to the atmosphere and to mitigate global warming. Leakage back to the atmosphere through abandoned wells and along faults would reduce the efficiency of carbon storage, possibly leading to health and ecological hazards at the ground surface, and possibly impacting water quality of near-surface dilute aquifers. We use static equilibrium and reactive transport simulations to test the hypothesis that perturbations in water chemistry associated with a CO2 gas leak into dilute groundwater are important measures for the potential release of CO2 to the atmosphere. Simulation parameters are constrained by groundwater chemistry, flow, and lithology from the High Plains aquifer. The High Plains aquifer is used to represent a typical sedimentary aquifer overlying a deep CO2 storage reservoir. Specifically, we address the relationships between CO2 flux, groundwater flow, detection time and distance. The CO2 flux ranges from 103 to 2 × 106 t/yr (0.63 to 1250 t/m2/yr to assess chemical perturbations resulting from relatively small leaks that may compromise long-term storage, water quality, and surface ecology, and larger leaks characteristic of short-term well failure. Results For the scenarios we studied, our simulations show pH and carbonate chemistry are good indicators for leakage of stored CO2 into an overlying aquifer because elevated CO2 yields a more acid pH than the ambient groundwater. CO2 leakage into a dilute groundwater creates a slightly acid plume that can be detected at some distance from the leak source due to groundwater flow and CO2 buoyancy. pH breakthrough curves demonstrate that CO2 leaks can be easily detected for CO2 flux ≥ 104 t/yr within a 15-month time period at a monitoring well screened within a permeable layer 500 m downstream from the vertical gas trace. At lower flux rates, the CO2 dissolves in the aqueous phase

  16. Geochemical detection of carbon dioxide in dilute aquifers.

    Science.gov (United States)

    Carroll, Susan; Hao, Yue; Aines, Roger

    2009-03-26

    Carbon storage in deep saline reservoirs has the potential to lower the amount of CO2 emitted to the atmosphere and to mitigate global warming. Leakage back to the atmosphere through abandoned wells and along faults would reduce the efficiency of carbon storage, possibly leading to health and ecological hazards at the ground surface, and possibly impacting water quality of near-surface dilute aquifers. We use static equilibrium and reactive transport simulations to test the hypothesis that perturbations in water chemistry associated with a CO2 gas leak into dilute groundwater are important measures for the potential release of CO2 to the atmosphere. Simulation parameters are constrained by groundwater chemistry, flow, and lithology from the High Plains aquifer. The High Plains aquifer is used to represent a typical sedimentary aquifer overlying a deep CO2 storage reservoir. Specifically, we address the relationships between CO2 flux, groundwater flow, detection time and distance. The CO2 flux ranges from 10(3) to 2 x 10(6) t/yr (0.63 to 1250 t/m2/yr) to assess chemical perturbations resulting from relatively small leaks that may compromise long-term storage, water quality, and surface ecology, and larger leaks characteristic of short-term well failure. For the scenarios we studied, our simulations show pH and carbonate chemistry are good indicators for leakage of stored CO2 into an overlying aquifer because elevated CO2 yields a more acid pH than the ambient groundwater. CO2 leakage into a dilute groundwater creates a slightly acid plume that can be detected at some distance from the leak source due to groundwater flow and CO2 buoyancy. pH breakthrough curves demonstrate that CO2 leaks can be easily detected for CO2 flux >or= 10(4) t/yr within a 15-month time period at a monitoring well screened within a permeable layer 500 m downstream from the vertical gas trace. At lower flux rates, the CO2 dissolves in the aqueous phase in the lower most permeable unit and does

  17. Relative influence of deposition and diagenesis on carbonate reservoir layering

    Energy Technology Data Exchange (ETDEWEB)

    Poli, Emmanuelle [Total E and P, Courbevoie (France); Javaux, Catherine [Total E and P, Pointe Noire (Congo)

    2008-07-01

    The architecture heterogeneities and petrophysical properties of carbonate reservoirs result from a combination of platform morphology, related depositional environments, relative sea level changes and diagenetic events. The reservoir layering built for static and dynamic modelling purposes should reflect the key heterogeneities (depositional or diagenetic) which govern the fluid flow patterns. The layering needs to be adapted to the goal of the modelling, ranging from full field computations of hydrocarbon volumes, to sector-based fine-scale simulations to test the recovery improvement. This paper illustrates various reservoir layering types, including schemes dominated by depositional architecture, and those more driven by the diagenetic overprint. The examples include carbonate platform reservoirs from different stratigraphic settings (Tertiary, Cretaceous, Jurassic and Permian) and different regions (Europe, Africa and Middle East areas). This review shows how significant stratigraphic surfaces (such as sequence boundaries or maximum flooding) with their associated facies shifts, can be often considered as key markers to constrain the reservoir layering. Conversely, how diagenesis (dolomitization and karst development), resulting in units with particular poroperm characteristics, may significantly overprint the primary reservoir architecture by generating flow units which cross-cut depositional sequences. To demonstrate how diagenetic processes can create reservoir bodies with geometries that cross-cut the depositional fabric, different types of dolomitization and karst development are illustrated. (author)

  18. Controls on Methane Occurrences in Aquifers Overlying the Eagle Ford Shale Play, South Texas.

    Science.gov (United States)

    Nicot, Jean-Philippe; Larson, Toti; Darvari, Roxana; Mickler, Patrick; Uhlman, Kristine; Costley, Ruth

    2017-07-01

    Assessing natural vs. anthropogenic sources of methane in drinking water aquifers is a critical issue in areas of shale oil and gas production. The objective of this study was to determine controls on methane occurrences in aquifers in the Eagle Ford Shale play footprint. A total of 110 water wells were tested for dissolved light alkanes, isotopes of methane, and major ions, mostly in the eastern section of the play. Multiple aquifers were sampled with approximately 47 samples from the Carrizo-Wilcox Aquifer (250-1200 m depth range) and Queen City-Sparta Aquifer (150-900 m depth range) and 63 samples from other shallow aquifers but mostly from the Catahoula Formation (depth methane, only deeper wells show significant dissolved methane (22 samples >1 mg/L, 10 samples >10 mg/L). No dissolved methane samples exhibit thermogenic characteristics that would link them unequivocally to oil and gas sourced from the Eagle Ford Shale. In particular, the well water samples contain very little or no ethane and propane (C1/C2+C3 molar ratio >453), unlike what would be expected in an oil province, but they also display relatively heavier δ 13 C methane (>-55‰) and δD methane (>-180‰). Samples from the deeper Carrizo and Queen City aquifers are consistent with microbial methane sourced from syndepositional organic matter mixed with thermogenic methane input, most likely originating from deeper oil reservoirs and migrating through fault zones. Active oxidation of methane pushes δ 13 C methane and δD methane toward heavier values, whereas the thermogenic gas component is enriched with methane owing to a long migration path resulting in a higher C1/C2+C3 ratio than in the local reservoirs. © 2017, National Ground Water Association.

  19. Imaging cross fault multiphase flow using time resolved high pressure-temperature synchrotron fluid tomography: implications for the geological storage of carbon dioxide within sandstone saline aquifers

    Science.gov (United States)

    Seers, Thomas; Andrew, Matthew; Bijeljic, Branko; Blunt, Martin; Dobson, Kate; Hodgetts, David; Lee, Peter; Menke, Hannah; Singh, Kamaljit; Parsons, Aaron

    2015-04-01

    Applied shear stresses within high porosity granular rocks result in characteristic deformation responses (rigid grain reorganisation, dilation, isovolumetric strain, grain fracturing and/or crushing) emanating from elevated stress concentrations at grain contacts. The strain localisation features produced by these processes are generically termed as microfaults (also shear bands), which occur as narrow tabular regions of disaggregated, rotated and/or crushed grains. Because the textural priors that favour microfault formation make their host rocks (esp. porous sandstones) conducive to the storage of geo-fluids, such structures are often abundant features within hydrocarbon reservoirs, aquifers and potential sites of CO2 storage (i.e. sandstone saline aquifers). The porosity collapse which accompanies microfault formation typically results in localised permeability reduction, often encompassing several orders of magnitude. Given that permeability is the key physical parameter that governs fluid circulation in the upper crust, this petrophysical degradation implicates microfaults as being flow impeding structures which may act as major baffles and/or barriers to fluid flow within the subsurface. Such features therefore have the potential to negatively impact upon hydrocarbon production or CO2 injection, making their petrophysical characterisation of considerable interest. Despite their significance, little is known about the pore-scale processes involved in fluid trapping and transfer within microfaults, particularly in the presence of multiphase flow analogous to oil accumulation, production and CO2 injection. With respect to the geological storage of CO2 within sandstone saline aquifers it has been proposed that even fault rocks with relatively low phyllosilicate content or minimal quartz cementation may act as major baffles or barriers to migrating CO2 plume. Alternatively, as ubiquitous intra-reservoir heterogeneities, micro-faults also have the potential to

  20. A reactive transport modeling approach to simulate biogeochemical processes in pore structures with pore-scale heterogeneities

    NARCIS (Netherlands)

    Gharasoo, M.G.; Centler, F.; Regnier, P.; Harms, H.; Thullner, M.

    2012-01-01

    Redox processes, including degradation of organic contaminants, are often controlled by microorganisms residing in natural porous media like soils or aquifers. These environments are characterized by heterogeneities at various scales which influence the transport of chemical species and the spatial

  1. Recovery of injected freshwater from a brackish aquifer with a multiwell system.

    Science.gov (United States)

    Miotliński, Konrad; Dillon, Peter J; Pavelic, Paul; Barry, Karen; Kremer, Sarah

    2014-01-01

    Herein we propose a multiple injection and recovery well system strategically operated for freshwater storage in a brackish aquifer. With the system we call aquifer storage transfer and recovery (ASTR) by using four injection and two production wells, we are capable of achieving both high recovery efficiency of injected freshwater and attenuation of contaminants through adequately long residence times and travel distances within the aquifer. The usual aquifer storage and recovery (ASR) scheme, in which a single well is used for injection and recovery, does not warrant consistent treatment of injected water due to the shorter minimum residence times and travel distances. We tested the design and operation of the system over 3 years in a layered heterogeneous limestone aquifer in Salisbury, South Australia. We demonstrate how a combination of detailed aquifer characterization and solute transport modeling can be used to maintain acceptable salinity of recovered water for its intended use along with natural treatment of recharge water. ASTR can be used to reduce treatment costs and take advantage of aquifers with impaired water quality that might locally not be otherwise beneficially used. © 2013, National Ground Water Association.

  2. Multi-scale nitrate transport in a sandstone aquifer system under intensive agriculture

    Science.gov (United States)

    Paradis, Daniel; Ballard, Jean-Marc; Lefebvre, René; Savard, Martine M.

    2018-03-01

    Nitrate transport in heterogeneous bedrock aquifers is influenced by mechanisms that operate at different spatial and temporal scales. To understand these mechanisms in a fractured sandstone aquifer with high porosity, a groundwater-flow and nitrate transport model—reproducing multiple hydraulic and chemical targets—was developed to explain the actual nitrate contamination observed in groundwater and surface water in a study area on Prince Edward Island, Canada. Simulations show that nitrate is leached to the aquifer year-round, with 61% coming from untransformed and transformed organic sources originating from fertilizers and manure. This nitrate reaches the more permeable shallow aquifer through fractures in weathered sandstone that represent only 1% of the total porosity (17%). Some of the nitrate reaches the underlying aquifer, which is less active in terms of groundwater flow, but most of it is drained to the main river. The river-water quality is controlled by the nitrate input from the shallow aquifer. Groundwater in the underlying aquifer, which has long residence times, is also largely influenced by the diffusion of nitrate in the porous sandstone matrix. Consequently, following a change of fertilizer application practices, water quality in domestic wells and the river would change rapidly due to the level of nitrate found in fractures, but a lag time of up to 20 years would be necessary to reach a steady level due to diffusion. This demonstrates the importance of understanding nitrate transport mechanisms when designing effective agricultural and water management plans to improve water quality.

  3. Contribution of environmental isotopes to the study of large aquifers in Morocco

    International Nuclear Information System (INIS)

    Kabbaj, A.; Zeryouhi, I.; Carlier, P.

    1978-01-01

    The geochemistry of environmental isotopes has been applied to several aquifers in Maroc, some of them quite large: Charf el Akab in the Tanger region, the Oum er Rbia basin and the Tadla aquifer, the free nappe of limnic limes tone in the Sais plane, and the lias limestone aquifer. The isotopic investigations on the basis of hydrogeochemical data have given more precise information on the supply conditions of these aquifers. The types of water of different origin from the Atlas or the phosphate plateau in the Sais plane and the Tadla basin have been distinguished, the supply from one aquifer to another Lias nappe which, via the flexures of the Sais plane, supplies the nappe of limic limestone has been assessed, the homogeneity or heterogeneity of these aquifers has been investigated as well as their impermeability, the Tadla aquifer and the special case of Charf el Akab compared with the marine region. The findings have proved the usefulness of these techniques and permitted a specification of the general conditions for their application. (orig.) [de

  4. Provision of Desalinated Irrigation Water by the Desalination of Groundwater within a Saline Aquifer

    Directory of Open Access Journals (Sweden)

    David D. J. Antia

    2016-12-01

    Full Text Available Irrigated land accounts for 70% of global water usage and 30% of global agricultural production. Forty percent of this water is derived from groundwater. Approximately 20%–30% of the groundwater sources are saline and 20%–50% of global irrigation water is salinized. Salinization reduces crop yields and the number of crop varieties which can be grown on an arable holding. Structured ZVI (zero valent iron, Fe0 pellets desalinate water by storing the removed ions as halite (NaCl within their porosity. This allows an “Aquifer Treatment Zone” to be created within an aquifer, (penetrated by a number of wells (containing ZVI pellets. This zone is used to supply partially desalinated water directly from a saline aquifer. A modeled reconfigured aquifer producing a continuous flow (e.g., 20 m3/day, 7300 m3/a of partially desalinated irrigation water is used to illustrate the impact of porosity, permeability, aquifer heterogeneity, abstraction rate, Aquifer Treatment Zone size, aquifer thickness, optional reinjection, leakage and flow by-pass on the product water salinity. This desalination approach has no operating costs (other than abstraction costs (and ZVI regeneration and may potentially be able to deliver a continuous flow of partially desalinated water (30%–80% NaCl reduction for $0.05–0.5/m3.

  5. The typology of Irish hard-rock aquifers based on an integrated hydrogeological and geophysical approach

    Science.gov (United States)

    Comte, Jean-Christophe; Cassidy, Rachel; Nitsche, Janka; Ofterdinger, Ulrich; Pilatova, Katarina; Flynn, Raymond

    2012-12-01

    Groundwater flow in hard-rock aquifers is strongly controlled by the characteristics and distribution of structural heterogeneity. A methodology for catchment-scale characterisation is presented, based on the integration of complementary, multi-scale hydrogeological, geophysical and geological approaches. This was applied to three contrasting catchments underlain by metamorphic rocks in the northern parts of Ireland (Republic of Ireland and Northern Ireland, UK). Cross-validated surface and borehole geophysical investigations confirm the discontinuous overburden, lithological compartmentalisation of the bedrock and important spatial variations of the weathered bedrock profiles at macro-scale. Fracture analysis suggests that the recent (Alpine) tectonic fabric exerts strong control on the internal aquifer structure at meso-scale, which is likely to impact on the anisotropy of aquifer properties. The combination of the interpretation of depth-specific hydraulic-test data with the structural information provided by geophysical tests allows characterisation of the hydrodynamic properties of the identified aquifer units. Regionally, the distribution of hydraulic conductivities can be described by inverse power laws specific to the aquifer litho-type. Observed groundwater flow directions reflect this multi-scale structure. The proposed integrated approach applies widely available investigative tools to identify key dominant structures controlling groundwater flow, characterising the aquifer type for each catchment and resolving the spatial distribution of relevant aquifer units and associated hydrodynamic parameters.

  6. Numerical simulation of the environmental impact of hydraulic fracturing of tight/shale gas reservoirs on near-surface groundwater: Background, base cases, shallow reservoirs, short-term gas, and water transport.

    Science.gov (United States)

    Reagan, Matthew T; Moridis, George J; Keen, Noel D; Johnson, Jeffrey N

    2015-04-01

    Hydrocarbon production from unconventional resources and the use of reservoir stimulation techniques, such as hydraulic fracturing, has grown explosively over the last decade. However, concerns have arisen that reservoir stimulation creates significant environmental threats through the creation of permeable pathways connecting the stimulated reservoir with shallower freshwater aquifers, thus resulting in the contamination of potable groundwater by escaping hydrocarbons or other reservoir fluids. This study investigates, by numerical simulation, gas and water transport between a shallow tight-gas reservoir and a shallower overlying freshwater aquifer following hydraulic fracturing operations, if such a connecting pathway has been created. We focus on two general failure scenarios: (1) communication between the reservoir and aquifer via a connecting fracture or fault and (2) communication via a deteriorated, preexisting nearby well. We conclude that the key factors driving short-term transport of gas include high permeability for the connecting pathway and the overall volume of the connecting feature. Production from the reservoir is likely to mitigate release through reduction of available free gas and lowering of reservoir pressure, and not producing may increase the potential for release. We also find that hydrostatic tight-gas reservoirs are unlikely to act as a continuing source of migrating gas, as gas contained within the newly formed hydraulic fracture is the primary source for potential contamination. Such incidents of gas escape are likely to be limited in duration and scope for hydrostatic reservoirs. Reliable field and laboratory data must be acquired to constrain the factors and determine the likelihood of these outcomes. Short-term leakage fractured reservoirs requires high-permeability pathways Production strategy affects the likelihood and magnitude of gas release Gas release is likely short-term, without additional driving forces.

  7. Sediment management for reservoir

    International Nuclear Information System (INIS)

    Rahman, A.

    2005-01-01

    All natural lakes and reservoirs whether on rivers, tributaries or off channel storages are doomed to be sited up. Pakistan has two major reservoirs of Tarbela and Managla and shallow lake created by Chashma Barrage. Tarbela and Mangla Lakes are losing their capacities ever since first impounding, Tarbela since 1974 and Mangla since 1967. Tarbela Reservoir receives average annual flow of about 62 MAF and sediment deposits of 0.11 MAF whereas Mangla gets about 23 MAF of average annual flows and is losing its storage at the rate of average 34,000 MAF annually. The loss of storage is a great concern and studies for Tarbela were carried out by TAMS and Wallingford to sustain its capacity whereas no study has been done for Mangla as yet except as part of study for Raised Mangla, which is only desk work. Delta of Tarbala reservoir has advanced to about 6.59 miles (Pivot Point) from power intakes. In case of liquefaction of delta by tremor as low as 0.12g peak ground acceleration the power tunnels I, 2 and 3 will be blocked. Minimum Pool of reservoir is being raised so as to check the advance of delta. Mangla delta will follow the trend of Tarbela. Tarbela has vast amount of data as reservoir is surveyed every year, whereas Mangla Reservoir survey was done at five-year interval, which has now been proposed .to be reduced to three-year interval. In addition suspended sediment sampling of inflow streams is being done by Surface Water Hydrology Project of WAPDA as also some bed load sampling. The problem of Chasma Reservoir has also been highlighted, as it is being indiscriminately being filled up and drawdown several times a year without regard to its reaction to this treatment. The Sediment Management of these reservoirs is essential and the paper discusses pros and cons of various alternatives. (author)

  8. Application of Integrated Reservoir Management and Reservoir Characterization to Optimize Infill Drillings. Annual technical progress report, June 13, 1996 to June 12, 1998

    Energy Technology Data Exchange (ETDEWEB)

    Nevans, Jerry W.; Blasingame, Tom; Doublet, Louis; Kelkar, Mohan; Freeman, George; Callard, Jeff; Moore, David; Davies, David; Vessell, Richard; Pregger, Brian; Dixon, Bill

    1999-04-27

    Infill drilling of wells on a uniform spacing, without regard to reservoir performance and characterization, does not optimize reservoir development because it fails to account for the complex nature of reservoir heterogeneities present in many low permeability reservoirs, and carbonate reservoirs in particular. New and emerging technologies, such as geostatistical modeling, rigorous decline curve analysis, reservoir rock typing, and special core analysis can be used to develop a 3-D simulation model for prediction of infill locations. Other technologies, such as inter-well injection tracers and magnetic flow conditioners, can also aid in the efficient evaluation and operation of both injection and producing wells. The purpose of this project was to demonstrate useful and cost effective methods of exploitation of the shallow shelf carbonate reservoirs of the Permian Basin located in West Texas.

  9. EPA Region 1 Sole Source Aquifers

    Science.gov (United States)

    This coverage contains boundaries of EPA-approved sole source aquifers. Sole source aquifers are defined as an aquifer designated as the sole or principal source of drinking water for a given aquifer service area; that is, an aquifer which is needed to supply 50% or more of the drinking water for the area and for which there are no reasonable alternative sources should the aquifer become contaminated.The aquifers were defined by a EPA hydrogeologist. Aquifer boundaries were then drafted by EPA onto 1:24000 USGS quadrangles. For the coastal sole source aquifers the shoreline as it appeared on the quadrangle was used as a boundary. Delineated boundaries were then digitized into ARC/INFO.

  10. The aquifer recharge: an overview of the legislative and planning aspect.

    Science.gov (United States)

    De Giglio, O; Caggiano, G; Apollonio, F; Marzella, A; Brigida, S; Ranieri, E; Lucentini, L; Uricchio, V F; Montagna, M T

    2018-01-01

    In most regions of the world, safeguarding groundwater resources is a serious issue, particularly in coastal areas where groundwater is the main water source for drinking, irrigation and industry. Water availability depends on climate, topography and geology. The aim of this paper is to evaluate aquifer recharge as a possible strategy to relieve water resource scarcity. Natural aquifer recharge is defined as the downward flow of water reaching the water table, increasing the groundwater reservoir. Hydro-meteorological factors (rainfall, evapotranspiration and runoff) may alter natural recharge processes. Artificial aquifer recharge is a process by which surface water is introduced with artificial systems underground to fill an aquifer. As a consequence of global warming that has increased the frequency and severity of natural disasters like the drought, the impacts of climate change and seasonality, the artificial recharge has been considered as a viable option. Different direct and indirect techniques can be used, and the choice depends on the hydrologic characteristics of a specific area. In Italy, Legislative Decree no. 152/06 plans artificial aquifer recharge as an additional measure in water management, and Decree no. 100/2016 establishes quantitative and qualitative conditions for recharge. Many projects examine aquifer recharge, such us WADIS-MAR in the southern Mediterranean region, WARBO in Italy and municipal wastewater treatment project in Apulia, a southern Italian region. However, aside from groundwater recharge, the community must foster a spirit of cooperation to manage groundwater as a sustainable resource.

  11. Construction of a carbonate reservoir model using pressure transient data : field case study

    Energy Technology Data Exchange (ETDEWEB)

    Taheri, S. [Petro-Iran, (Iran, Islamic Republic of); Ghanizadeh, M. [Tehran Energy, (Iran, Islamic Republic of); Haghighi, M. [Tehran Univ., (Iran, Islamic Republic of)

    2004-07-01

    Pressure transient data was integrated with other reservoir information to create a geological model of a carbonate reservoir in the Salaman offshore field in Iran. The model was created using seismic and well log data as well as the interpretation of 99 well tests performed in this field. Several features such as sealing faults, aquifer, fracturing and layering systems were observed. Two faults were identified in the northern part of the reservoir. The distance between the major fault and well number 27 was less than predicted from seismic data. An active aquifer and minor fault were also identified near well number 6. A fracture system was identified around well number 22. Most well tests showed communication between different layers of the reservoirs, suggesting interconnected layers in terms of geology. All calculated permeabilities from the well tests were found to be significantly higher than those from core analysis, suggesting that discrete fractures exist throughout the reservoir. The northern region of the reservoir has the highest permeability values and the lowest values are observed in the central part of the reservoir. 18 refs., 6 figs.

  12. Benzene dynamics and biodegradation in alluvial aquifers affected by river fluctuations.

    Science.gov (United States)

    Batlle-Aguilar, J; Morasch, B; Hunkeler, D; Brouyère, S

    2014-01-01

    The spatial distribution and temporal dynamics of a benzene plume in an alluvial aquifer strongly affected by river fluctuations was studied. Benzene concentrations, aquifer geochemistry datasets, past river morphology, and benzene degradation rates estimated in situ using stable carbon isotope enrichment were analyzed in concert with aquifer heterogeneity and river fluctuations. Geochemistry data demonstrated that benzene biodegradation was on-going under sulfate reducing conditions. Long-term monitoring of hydraulic heads and characterization of the alluvial aquifer formed the basis of a detailed modeled image of aquifer heterogeneity. Hydraulic conductivity was found to strongly correlate with benzene degradation, indicating that low hydraulic conductivity areas are capable of sustaining benzene anaerobic biodegradation provided the electron acceptor (SO4 (2-) ) does not become rate limiting. Modeling results demonstrated that the groundwater flux direction is reversed on annual basis when the river level rises up to 2 m, thereby forcing the infiltration of oxygenated surface water into the aquifer. The mobilization state of metal trace elements such as Zn, Cd, and As present in the aquifer predominantly depended on the strong potential gradient within the plume. However, infiltration of oxygenated water was found to trigger a change from strongly reducing to oxic conditions near the river, causing mobilization of previously immobile metal species and vice versa. MNA appears to be an appropriate remediation strategy in this type of dynamic environment provided that aquifer characterization and targeted monitoring of redox conditions are adequate and electron acceptors remain available until concentrations of toxic compounds reduce to acceptable levels. © 2013, National Ground Water Association.

  13. Reservoir Characterization of Upper Devonian Gordon Sandstone, Jacksonburg, Stringtown Oil Field, Northwestern West Virginia

    Energy Technology Data Exchange (ETDEWEB)

    Ameri, S.; Aminian, K.; Avary, K.L.; Bilgesu, H.I.; Hohn, M.E.; McDowell, R.R.; Patchen, D.L.

    2002-05-21

    The purpose of this work was to establish relationships among permeability, geophysical and other data by integrating geologic, geophysical and engineering data into an interdisciplinary quantification of reservoir heterogeneity as it relates to production.

  14. Hydrochemical and isotopic (δ18O, δ2H, 87Sr/86Sr, δ37Cl and δ81Br) evidence for the origin of saline formation water in a gas reservoir

    NARCIS (Netherlands)

    Bagheri, R.; Nadri, A.; Raeisi, E.; Eggenkamp, H.G.M.; Kazemi, G.A.; Montaseri, A.

    2014-01-01

    The Permo-Triassic Kangan gasfield in southern Iran is composed of an aquifer, the Kangan Aquifer (KA), and an overlying gas reservoir. It is located in the Kangan and Dalan Formations and consists predominantly of limestone and dolomite. The Kangan gasfield is exploited from 36 wells at depths from

  15. Relationship of regional water quality to aquifer thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Allen, R.D.

    1983-11-01

    Ground-water quality and associated geologic characteristics may affect the feasibility of aquifer thermal energy storage (ATES) system development in any hydrologic region. This study sought to determine the relationship between ground-water quality parameters and the regional potential for ATES system development. Information was collected from available literature to identify chemical and physical mechanisms that could adversely affect an ATES system. Appropriate beneficiation techniques to counter these potential geochemical and lithologic problems were also identified through the literature search. Regional hydrology summaries and other sources were used in reviewing aquifers of 19 drainage regions in the US to determine generic geochemical characteristics for analysis. Numerical modeling techniques were used to perform geochemical analyses of water quality from 67 selected aquifers. Candidate water resources regions were then identified for exploration and development of ATES. This study identified six principal mechanisms by which ATES reservoir permeability may be impaired: (1) particulate plugging, (2) chemical precipitation, (3) liquid-solid reactions, (4) formation disaggregation, (5) oxidation reactions, and (6) biological activity. Specific proven countermeasures to reduce or eliminate these effects were found. Of the hydrologic regions reviewed, 10 were identified as having the characteristics necessary for ATES development: (1) Mid-Atlantic, (2) South-Atlantic Gulf, (3) Ohio, (4) Upper Mississippi, (5) Lower Mississippi, (6) Souris-Red-Rainy, (7) Missouri Basin, (8) Arkansas-White-Red, (9) Texas-Gulf, and (10) California.

  16. Reservoir characterization of Pennsylvanian sandstone reservoirs. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, M.

    1995-02-01

    This final report summarizes the progress during the three years of a project on Reservoir Characterization of Pennsylvanian Sandstone Reservoirs. The report is divided into three sections: (i) reservoir description; (ii) scale-up procedures; (iii) outcrop investigation. The first section describes the methods by which a reservoir can be described in three dimensions. The next step in reservoir description is to scale up reservoir properties for flow simulation. The second section addresses the issue of scale-up of reservoir properties once the spatial descriptions of properties are created. The last section describes the investigation of an outcrop.

  17. Prediction of Gas Injection Performance for Heterogeneous Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Blunt, M.J.; Orr, F.M. Jr.

    2001-03-26

    This report was an integrated study of the physics and chemistry affecting gas injection, from the pore scale to the field scale, and involved theoretical analysis, laboratory experiments and numerical simulation. Specifically, advances were made on streamline-based simulation, analytical solutions to 1D compositional displacements, and modeling and experimental measures of three-phase flow.

  18. Discrete Feature Approach for Heterogeneous Reservoir Production Enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Dershowitz, William S.; Cladouhos, Trenton

    2001-09-06

    This progress report describes activities during the period January 1, 1999 to June 30, 1999. Work was carried out on 21 tasks. The major activity during the reporting period was the development and preliminary application of discrete fracture network (DFN) models for Stoney Point, South Oregon Basin, and North Oregon Basins project study sites. In addition, research was carried out on analysis algorithms for discrete future orientation.

  19. Improving CO2 Efficiency for Recovering Oil in Heterogeneous Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Grigg, Reid B.; Svec, Robert K.

    2003-03-10

    The work strived to improve industry understanding of CO2 flooding mechanisms with the ultimate goal of economically recovering more of the U.S. oil reserves. The principle interests are in the related fields of mobility control and injectivity.

  20. pressure distribution in a layered reservoir with gas-cap and bottom

    African Journals Online (AJOL)

    2012-07-02

    Jul 2, 2012 ... pressure derivatives, interlayer cross flow, heterogeneity, reservoir characterization, pressure distribution, dimensionless pressure. 1. Introduction. Oil production from a layered reservoir with a top gas cap and bottom water acting simultaneously poses serious challenges of rate and pressure monitoring.

  1. Water balance of global aquifers revealed by groundwater footprint.

    Science.gov (United States)

    Gleeson, Tom; Wada, Yoshihide; Bierkens, Marc F P; van Beek, Ludovicus P H

    2012-08-09

    Groundwater is a life-sustaining resource that supplies water to billions of people, plays a central part in irrigated agriculture and influences the health of many ecosystems. Most assessments of global water resources have focused on surface water, but unsustainable depletion of groundwater has recently been documented on both regional and global scales. It remains unclear how the rate of global groundwater depletion compares to the rate of natural renewal and the supply needed to support ecosystems. Here we define the groundwater footprint (the area required to sustain groundwater use and groundwater-dependent ecosystem services) and show that humans are overexploiting groundwater in many large aquifers that are critical to agriculture, especially in Asia and North America. We estimate that the size of the global groundwater footprint is currently about 3.5 times the actual area of aquifers and that about 1.7 billion people live in areas where groundwater resources and/or groundwater-dependent ecosystems are under threat. That said, 80 per cent of aquifers have a groundwater footprint that is less than their area, meaning that the net global value is driven by a few heavily overexploited aquifers. The groundwater footprint is the first tool suitable for consistently evaluating the use, renewal and ecosystem requirements of groundwater at an aquifer scale. It can be combined with the water footprint and virtual water calculations, and be used to assess the potential for increasing agricultural yields with renewable groundwaterref. The method could be modified to evaluate other resources with renewal rates that are slow and spatially heterogeneous, such as fisheries, forestry or soil.

  2. A METHODOLOGY TO INTEGRATE MAGNETIC RESONANCE AND ACOUSTIC MEASUREMENTS FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Jorge O. Parra; Chris L. Hackert; Lorna L. Wilson

    2002-09-20

    The work reported herein represents the third year of development efforts on a methodology to interpret magnetic resonance and acoustic measurements for reservoir characterization. In this last phase of the project we characterize a vuggy carbonate aquifer in the Hillsboro Basin, Palm Beach County, South Florida, using two data sets--the first generated by velocity tomography and the second generated by reflection tomography. First, we integrate optical macroscopic (OM), scanning electron microscope (SEM) and x-ray computed tomography (CT) images, as well as petrography, as a first step in characterizing the aquifer pore system. This pore scale integration provides information with which to evaluate nuclear magnetic resonance (NMR) well log signatures for NMR well log calibration, interpret ultrasonic data, and characterize flow units at the field scale between two wells in the aquifer. Saturated and desaturated NMR core measurements estimate the irreducible water in the rock and the variable T{sub 2} cut-offs for the NMR well log calibration. These measurements establish empirical equations to extract permeability from NMR well logs. Velocity and NMR-derived permeability and porosity relationships integrated with velocity tomography (based on crosswell seismic measurements recorded between two wells 100 m apart) capture two flow units that are supported with pore scale integration results. Next, we establish a more detailed picture of the complex aquifer pore structures and the critical role they play in water movement, which aids in our ability to characterize not only carbonate aquifers, but reservoirs in general. We analyze petrography and cores to reveal relationships between the rock physical properties that control the compressional and shear wave velocities of the formation. A digital thin section analysis provides the pore size distributions of the rock matrix, which allows us to relate pore structure to permeability and to characterize flow units at the

  3. Reservoir lithology determination from seismic inversion results using markov processes

    NARCIS (Netherlands)

    Feng, R.

    2017-01-01

    For reservoir characterization, the subsurface heterogeneity needs to be qualified in which the distribution of lithologies is an essential part since it determines the location and migration paths of hydrocarbons. Preliminary analysis of well-log data could help to identify various lithologies in a

  4. As contamination in Mercedes aquifer groundwater

    International Nuclear Information System (INIS)

    Goso, C; Manganelli, A; Fernandez, T; Garcia, M; Gimeno, D; Perez, C.

    2006-01-01

    This work is about the quality of the groundwater an the arsenic content in different aquifers in Uruguay. The first data obtained of arsenic concentrations are from subterranes water in the Mercedes aquifers

  5. The Citronelle aquifers in Mississippi

    Science.gov (United States)

    Boswell, E.H.

    1979-01-01

    The Citronelle aquifers consist of sand and gravel of Pliocene age that forms a discontinuous outcrop area of about 6,000 square miles in southern Mississippi. The beds dip to the south at an average rate of about 6 feet per mile. The unconfined aquifers are used mostly for domestic and farm use but also supply water to several municipalities and industries. The average saturated thickness of the aquifers is about 45 feet. This physically limits drawdown space and, although specific capacities are high, yields generally do not exceed a few hundred gallons per minute. Water levels have not declined significantly because withdrawals are small. Water quality is generally good although in some places there are objectionally high concentrations iron and in some the water is acidic.

  6. Ensemble-Based Data Assimilation in Reservoir Characterization: A Review

    Directory of Open Access Journals (Sweden)

    Seungpil Jung

    2018-02-01

    Full Text Available This paper presents a review of ensemble-based data assimilation for strongly nonlinear problems on the characterization of heterogeneous reservoirs with different production histories. It concentrates on ensemble Kalman filter (EnKF and ensemble smoother (ES as representative frameworks, discusses their pros and cons, and investigates recent progress to overcome their drawbacks. The typical weaknesses of ensemble-based methods are non-Gaussian parameters, improper prior ensembles and finite population size. Three categorized approaches, to mitigate these limitations, are reviewed with recent accomplishments; improvement of Kalman gains, add-on of transformation functions, and independent evaluation of observed data. The data assimilation in heterogeneous reservoirs, applying the improved ensemble methods, is discussed on predicting unknown dynamic data in reservoir characterization.

  7. Enhancing drought resilience with conjunctive use and managed aquifer recharge in California and Arizona

    Science.gov (United States)

    Scanlon, Bridget R.; Reedy, Robert C.; Faunt, Claudia; Pool, Donald R.; Uhlman, Kristine;

    2016-01-01

    Projected longer‐term droughts and intense floods underscore the need to store more water to manage climate extremes. Here we show how depleted aquifers have been used to store water by substituting surface water use for groundwater pumpage (conjunctive use, CU) or recharging groundwater with surface water (Managed Aquifer Recharge, MAR). Unique multi‐decadal monitoring from thousands of wells and regional modeling datasets for the California Central Valley and central Arizona were used to assess CU and MAR. In addition to natural reservoir capacity related to deep water tables, historical groundwater depletion further expanded aquifer storage by ~44 km3 in the Central Valley and by ~100 km3 in Arizona, similar to or exceeding current surface reservoir capacity by up to three times. Local river water and imported surface water, transported through 100s of km of canals, is substituted for groundwater (≤15 km3/yr, CU) or is used to recharge groundwater (MAR, ≤1.5 km3/yr) during wet years shifting to mostly groundwater pumpage during droughts. In the Central Valley, CU and MAR locally reversed historically declining water‐level trends, which contrasts with simulated net regional groundwater depletion. In Arizona, CU and MAR also reversed historically declining groundwater level trends in Active Management Areas. These rising trends contrast with current declining trends in irrigated areas that lack access to surface water to support CU or MAR. Use of depleted aquifers as reservoirs could expand with winter flood irrigation or capturing flood discharges to the Pacific (0 – 1.6 km3/yr, 2000–2014) with additional infrastructure in California. Because flexibility and expanded portfolio options translate to resilience, CU and MAR enhance drought resilience through multi‐year storage, complementing shorter term surface reservoir storage, and facilitating water markets.

  8. Enhancing drought resilience with conjunctive use and managed aquifer recharge in California and Arizona

    Science.gov (United States)

    Scanlon, Bridget R.; Reedy, Robert C.; Faunt, Claudia C.; Pool, Donald; Uhlman, Kristine

    2016-03-01

    Projected longer-term droughts and intense floods underscore the need to store more water to manage climate extremes. Here we show how depleted aquifers have been used to store water by substituting surface water use for groundwater pumpage (conjunctive use, CU) or recharging groundwater with surface water (managed aquifer recharge, MAR). Unique multi-decadal monitoring from thousands of wells and regional modeling datasets for the California Central Valley and central Arizona were used to assess CU and MAR. In addition to natural reservoir capacity related to deep water tables, historical groundwater depletion further expanded aquifer storage by ˜44 km3 in the Central Valley and by ˜100 km3 in Arizona, similar to or exceeding current surface reservoir capacity by up to three times. Local river water and imported surface water, transported through 100s of km of canals, is substituted for groundwater (≤15 km3 yr-1, CU) or is used to recharge groundwater (MAR, ≤1.5 km3 yr-1) during wet years shifting to mostly groundwater pumpage during droughts. In the Central Valley, CU and MAR locally reversed historically declining water-level trends, which contrasts with simulated net regional groundwater depletion. In Arizona, CU and MAR also reversed historically declining groundwater level trends in active management areas. These rising trends contrast with current declining trends in irrigated areas that lack access to surface water to support CU or MAR. Use of depleted aquifers as reservoirs could expand with winter flood irrigation or capturing flood discharges to the Pacific (0-1.6 km3 yr-1, 2000-2014) with additional infrastructure in California. Because flexibility and expanded portfolio options translate to resilience, CU and MAR enhance drought resilience through multi-year storage, complementing shorter term surface reservoir storage, and facilitating water markets.

  9. Lateral groundwater inflows into alluvial aquifers of main alpine valleys

    Science.gov (United States)

    Burger, Ulrich

    2015-04-01

    In alpine regions the topography is mainly characterised by deep incised valleys, mountain slopes and ridges. Usually the main valleys contain aquifers in alluvial soft rock. Lateral these aquifers are confined by mountainous hard rock slopes covered by heterogeneous sediments with different thickness. The slopes can be incised by lateral valleys. Numerical models for the main alluvial aquifers ask for lateral hydrogeological boundaries. Usually no flow boundaries or Constant head Boundaries are used, even if the lateral inflows to the main aquifers are rarely known. In this example a data set for a detailed investigated and monitored area is studied to give an answer on the location and the quantification of these lateral subsurface inflows. The study area is a typical main alpine valley with a thick alluvial aquifer (appr. 120m thick), lateral confined by granite, covered at the base of the steep slopes by quaternary sediments (Burger at al. 2012). The study consists of several steps 1.) Analytical calculation of the inflows on the base of investigated and monitored 2d profiles along fault zones (Perello et al 2013) which pinch out in the main valley 2.) Analytical models along typical W-dipping slopes with monitored slope springs 3.) Evaluating temperature and electrical conductivity profiles measured in approx. 30 groundwater wells in the alluvial aquifers and along the slopes to locate main lateral subsurface inflows 4.) Output of a regional model used for the hydrogeological back analyses of the excavation of a tunnel (Baietto et al. 2014) 5.) Output of a local numerical model calibrated with a monitoring dataset and results of a pumping test of big scale (450l/s for 10days) Results of these analyses are shown to locate and quantify the lateral groundwater inflows in the main alluvial aquifer. References Baietto A., Burger U., Perello P. (2014): Hydrogeological modelling applications in tunnel excavations: examples from tunnel excavations in granitic rocks

  10. Aquifers Characterization and Productivity in Ellala Catchment ...

    African Journals Online (AJOL)

    This paper assesses the aquifer characteristics and productivity nature of different rocks and sediments using geological and hydrogeological methods in Ellala ... Hydrodynamic analyses of the aquifers reveal that in the limestone aquifer hydraulic conductivity is ranging from 0.046 to 4.65 m/day with a mean value of 1.44 ...

  11. Numerical simulation of pore size dependent anhydrite precipitation in geothermal reservoirs

    Science.gov (United States)

    Mürmann, Mario; Kühn, Michael; Pape, Hansgeorg; Clauser, Christoph

    2013-04-01

    cementation in a 2D hypothetical core flooding experiment. With this new approach cementation patterns observed in the Allermöhe core samples can be explained now. The obtained results show that the variation of fluid supersaturation within a pore governs spatially heterogeneous anhydrite cementation. This variation and the fluid velocity determine the precipitation. Our numerical simulation results clearly emphasize the necessity to consider the spatial variation of supersaturation on the pore scale. References Baermann A., Kroeger J., Taugs R., Wuestenhagen K., Zarth M. (2000) Anhydrite cementation in Rhaetian Sandstone in Hamburg - Morphology and Structures, Zeitschrift für Angewandte Geologie, 46(3), 138-143 (in German). Clauser C. (2003) Numerical Simulation of Reactive Flow in Hot Aquifers. SHEMAT and processing SHEMAT, Springer Publishers, Heidelberg. Emmanuel S., Berkowitz B. (2007) Effects of pore size controlled solubility on reactive transport in heterogeneous rock, Geophysical Research Letters, 34, L06404. Putnis A., Mauthe G. (2001) The effect of pore size on cementation in porous rocks, Geofluids, 1, 37-41. Wagner R., Kühn M., Meyn V., Pape H., Vath U., Clauser C. (2005) Numerical simulation of pore space clogging in geothermal reservoirs by precipitation of anhydrite. International Journal of Rock Mechanics and Mining Sciences 42, 1070-1081, doi: 10.1016/ j.ijrmms.2005.05.008.

  12. Optimising reservoir operation

    DEFF Research Database (Denmark)

    Ngo, Long le

    Anvendelse af optimeringsteknik til drift af reservoirer er blevet et væsentligt element i vandressource-planlægning og -forvaltning. Traditionelt har reservoirer været styret af heuristiske procedurer for udtag af vand, suppleret i en vis udstrækning af subjektive beslutninger. Udnyttelse af...... reservoirer involverer en lang række interessenter med meget forskellige formål (f.eks. kunstig vanding, vandkraft, vandforsyning mv.), og optimeringsteknik kan langt bedre lede frem til afbalancerede løsninger af de ofte modstridende interesser. Afhandlingen foreslår en række tiltag, hvormed traditionelle...... driftsstrategier kan erstattes af optimale strategier baseret på den nyeste udvikling indenfor computer-baserede beregninger. Hovedbidraget i afhandlingen er udviklingen af et beregningssystem, hvori en simuleringsmodel er koblet til en model for optimering af nogle udvalgte beslutningsvariable, der i særlig grad...

  13. Evaluation of simplified stream-aquifer depletion models for water rights administration

    Science.gov (United States)

    Sophocleous, Marios; Koussis, Antonis; Martin, J.L.; Perkins, S.P.

    1995-01-01

    We assess the predictive accuracy of Glover's (1974) stream-aquifer analytical solutions, which are commonly used in administering water rights, and evaluate the impact of the assumed idealizations on administrative and management decisions. To achieve these objectives, we evaluate the predictive capabilities of the Glover stream-aquifer depletion model against the MODFLOW numerical standard, which, unlike the analytical model, can handle increasing hydrogeologic complexity. We rank-order and quantify the relative importance of the various assumptions on which the analytical model is based, the three most important being: (1) streambed clogging as quantified by streambed-aquifer hydraulic conductivity contrast; (2) degree of stream partial penetration; and (3) aquifer heterogeneity. These three factors relate directly to the multidimensional nature of the aquifer flow conditions. From these considerations, future efforts to reduce the uncertainty in stream depletion-related administrative decisions should primarily address these three factors in characterizing the stream-aquifer process. We also investigate the impact of progressively coarser model grid size on numerically estimating stream leakage and conclude that grid size effects are relatively minor. Therefore, when modeling is required, coarser model grids could be used thus minimizing the input data requirements.

  14. Finite analytic numerical method for three-dimensional fluid flow in heterogeneous porous media

    Science.gov (United States)

    Wang, Yan-Feng; Liu, Zhi-Feng; Wang, Xiao-Hong

    2014-12-01

    Understanding fluid flows in heterogeneous porous media is fundamental to applied geosciences. The wide connectivity variations in the natural aquifer or oil reservoirs make the equivalent permeability have strong spatial variations. When performing the simulations for subsurface flows, the permeabilities may have strong discontinuities across the interfaces between different grid cells. Utilizing the traditional numerical schemes to simulate flows in strong heterogeneous media, the refinement ratio for the grid cell needs to increase dramatically to get an accurate result. Recently, we proposed a finite analytic numerical scheme to solve the two-dimensional fluid flows in heterogeneous porous media. With only 2 × 2 or 3 × 3 subdivisions, this scheme can provide rather accurate solutions. In this paper, we develop the finite analytic numerical method for solving the three-dimensional fluid flows in heterogeneous porous media. For the rectangular grid system, it is generally proposed that the pressure gradient in a plane normal to the edge joining different permeability regions will tend to infinite as approaching the edge according to a typical power-law solution and the tangential derivate of the pressure along the edge must be of limited value due to the pressure continuity. Consequently, the three-dimensional flow will reduce to the two-dimensional one in the neighborhood around each edge. Such quasi-two-dimensional behavior is then applied to construct a finite analytic numerical scheme. Numerical examples show that the proposed scheme can provide rather accurate solutions with only 2 × 2 × 2 or 3 × 3 × 3 subdivisions and the convergent speed is independent of the permeability heterogeneity. Due to its high calculation efficiency, the proposed scheme is utilized to test the well known LLM (Landau, Lifshitz and Matheron) conjecture, which provides keq /kG = exp ⁡ (1/6σln⁡k2) for the isotropic log-normal porous medium. The numerical results do not

  15. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    International Nuclear Information System (INIS)

    Kumar, Raj; Keith Brown; Hickman, Scott T.; Justice, James J.

    2000-01-01

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO 2 ) stimulation treatments; (6) Hydraulic fracturing design and monitoring; and (7) Mobility control agents

  16. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    Energy Technology Data Exchange (ETDEWEB)

    T. Scott Hickman; James J. Justice

    2001-06-16

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs. Therefore, the majority of Budget Period 1 was devoted to reservoir characterization. Technologies being demonstrated include: (1) Advanced petrophysics; (2) Three-dimensional (3-D) seismic; (3) Crosswell bore tomography; (4) Advanced reservoir simulation; (5) Carbon dioxide (CO{sub 2}) stimulation treatments; (6) Hydraulic fracturing design and monitoring; and (7) Mobility control agents.

  17. Arsenic levels in groundwater aquifer

    African Journals Online (AJOL)

    Miodrag Jelic

    5Faculty of Ecology and Environmental Sciences, Union-Nikola Tesla University, Belgrade, Serbia. 6Department of Chemistry, Faculty of Science, University of Kragujevac, Kragujevac, Serbia. Accepted 31 December, 2012. As part of a survey on the groundwater aquifer at the Neoplanta source site, standard laboratory.

  18. Geothermal reservoir engineering

    CERN Document Server

    Grant, Malcolm Alister

    2011-01-01

    As nations alike struggle to diversify and secure their power portfolios, geothermal energy, the essentially limitless heat emanating from the earth itself, is being harnessed at an unprecedented rate.  For the last 25 years, engineers around the world tasked with taming this raw power have used Geothermal Reservoir Engineering as both a training manual and a professional reference.  This long-awaited second edition of Geothermal Reservoir Engineering is a practical guide to the issues and tasks geothermal engineers encounter in the course of their daily jobs. The bo

  19. Session: Reservoir Technology

    Energy Technology Data Exchange (ETDEWEB)

    Renner, Joel L.; Bodvarsson, Gudmundur S.; Wannamaker, Philip E.; Horne, Roland N.; Shook, G. Michael

    1992-01-01

    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five papers: ''Reservoir Technology'' by Joel L. Renner; ''LBL Research on the Geysers: Conceptual Models, Simulation and Monitoring Studies'' by Gudmundur S. Bodvarsson; ''Geothermal Geophysical Research in Electrical Methods at UURI'' by Philip E. Wannamaker; ''Optimizing Reinjection Strategy at Palinpinon, Philippines Based on Chloride Data'' by Roland N. Horne; ''TETRAD Reservoir Simulation'' by G. Michael Shook

  20. Putting integrated reservoir characterization into practice - in house training

    Energy Technology Data Exchange (ETDEWEB)

    Wright, F.M. Jr.; Best, D.A.; Clarke, R.T. [Mobile Exploration and Producing Technical Center, Dallas, TX (United States)

    1997-08-01

    The need for even more efficient reservoir characterization and management has forced a change in the way Mobil Oil provides technical support to its production operations. We`ve learned that to be successful, a good understanding of the reservoir is essential. This includes an understanding of the technical and business significance of reservoir heterogeneities at different stages of field development. A multi-disciplinary understanding of the business of integrated reservoir characterization is essential and to facilitate this understanding, Mobil has developed a highly successful {open_quotes}Reservoir Characterization Field Seminar{close_quotes}. Through specific team based case studies that incorporate outcrop examples and data the program provides participants the opportunity to explore historic and alternative approaches to reservoir description, characterization and management. We explore appropriate levels and timing of data gathering, technology applications, risk assessment and management practices at different stages of field development. The case studies presented throughout the course are a unique element of the program which combine real life and hypothetical problem sets that explore how different technical disciplines interact, the approaches to a problem solving they use, the assumptions and uncertainties contained in their contributions and the impact those conclusions may have on other disciplines involved in the overall reservoir management process. The team building aspect of the course was an added bonus.

  1. Formation evaluation and well-test analysis for complex interpretation of reservoir permeability distribution

    Science.gov (United States)

    Korovin, M. O.; Merkulov, V. P.

    2014-08-01

    Data on heterogeneity of porous space and reservoir filtration properties determines the choice of most effective development strategy. The comparative analysis of well-logging and well-test results was carried out to determine the value of filtration heterogeneity. The similarity of the results obtained using different methods makes it possible to predict orientation of enhanced permeability.

  2. Sequestration of carbon in saline aquifers - mathematical and numerical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nordbotten, Jan Martin

    2004-01-01

    The work in this thesis focuses equally on two main topics. The set of these subjects deals with development of criteria for monotonicity of control volume methods. These methods are important and frequently used for solving the pressure equation arising in porous media flow. First we consider homogeneous parallelogram grids, and subsequently general logical Cartesian grids in heterogeneous media. This subject is concluded by the development of a new class of Multi Point Flux Approximation methods, motivated by the monotonicity results obtained. The second topic of this thesis is the development of analytical and semi- analytical solutions to the problem of leakage through abandoned wells. More specially, we look at a set of aquifers, separated by impermeable layers (aquicludes), where injection of water or CO{sub 2} takes place in some or all the aquifers. The aquifers and aquicludes are frequently penetrated by abandoned wells from oil exploration, and our problem consists of finding solutions to flow and leakage through these wells. The goal is to obtain expressions for leakage rates that may be evaluated quickly enough such that Monte Carlo realizations over statistical distributions of properties for abandoned wells can be performed. (author)

  3. Aquifer thermal energy stores in Germany

    International Nuclear Information System (INIS)

    Kabus, F.; Seibt, P.; Poppei, J.

    2000-01-01

    This paper describes the state of essential demonstration projects of heat and cold storage in aquifers in Germany. Into the energy supply system of the buildings of the German Parliament in Berlin, there are integrated both a deep brine-bearing aquifer for the seasonal storage of waste heat from power and heat cogeneration and a shallow-freshwater bearing aquifer for cold storage. In Neubrandenburg, a geothermal heating plant which uses a 1.200 m deep aquifer is being retrofitted into an aquifer heat storage system which can be charged with the waste heat from a gas and steam cogeneration plant. The first centralised solar heating plant including an aquifer thermal energy store in Germany was constructed in Rostock. Solar collectors with a total area of 1000m 2 serve for the heating of a complex of buildings with 108 flats. A shallow freshwater-bearing aquifer is used for thermal energy storage. (Authors)

  4. Aquifer Characteristics Data Report for the Weldon Spring Site chemical plant/raffinate pits and vicinity properties for the Weldon Spring Site Remedial Action Project, Weldon Spring, Missouri

    International Nuclear Information System (INIS)

    1990-11-01

    This report describes the procedures and methods used, and presents the results of physical testing performed, to characterize the hydraulic properties of the shallow Mississippian-Devonian aquifer beneath the Weldon Spring chemical plant, raffinate pits, and vicinity properties. The aquifer of concern is composed of saturated rocks of the Burlington-Keokuk Limestone which constitutes the upper portion of the Mississippian-Devonian aquifer. This aquifer is a heterogeneous anisotropic medium which can be described in terms of diffuse Darcian flow overlain by high porosity discrete flow zones and conduits. Average hydraulic conductivity for all wells tested is 9.6E-02 meters/day (3.1E-01 feet/day). High hydraulic conductivity values are representative of discrete flow in the fractured and weathered zones in the upper Burlington-Keokuk Limestone. They indicate heterogeneities within the Mississippian-Devonian aquifer. Aquifer heterogeneity in the horizontal plane is believed to be randomly distributed and is a function of fracture spacing, solution voids, and preglacial weathering phenomena. Relatively high hydraulic conductivities in deeper portions of the aquifer are though to be due to the presence of widely spaced fractures. 44 refs., 27 figs., 9 tabs

  5. Characterization of dynamic change of Fan-delta reservoir properties in water-drive development

    Energy Technology Data Exchange (ETDEWEB)

    Wu Shenghe; Xiong Qihua; Liu Yuhong [Univ. of Petroleum Changping, Beijing (China)

    1997-08-01

    Fan-delta reservoir in Huzhuangji oil field of east China, is a typical highly heterogeneous reservoir. The oil field has been developed by water-drive for 10 years, but the oil recovery is less than 12%, and water cut is over 90%, resulting from high heterogeneity and serious dynamic change of reservoir properties. This paper aims at the study of dynamic change of reservoir properties in water-drive development. Through quantitative imaging analysis and mercury injection analysis of cores from inspection wells, the dynamic change of reservoir pore structure in water-drive development was studied. The results show that the {open_quotes}large pore channels{close_quotes} develop in distributary channel sandstone and become larger in water-drive development, resulting in more serious pore heterogeneity. Through reservoir sensitivity experiments, the rock-fluid reaction in water-drive development is studied. The results show the permeability of some distal bar sandstone and deserted channel sandstone becomes lower due to swelling of I/S clay minerals in pore throats. OD the other hand, the permeability of distributary channel and mouth bar sandstone become larger because the authigenic Koalinites in pore throats are flushed away with the increase of flow rate of injection water. Well-logging analysis of flooded reservoirs are used to study the dynamic change of reservoir properties in various flow units. The distribution of remaining oil is closely related to the types and distribution of flow units.

  6. Hydrogeologic and hydraulic characterization of aquifer and nonaquifer layers in a lateritic terrain (West Bengal, India)

    Science.gov (United States)

    Biswal, Sabinaya; Jha, Madan K.; Sharma, Shashi P.

    2018-02-01

    The hydrogeologic and hydraulic characteristics of a lateritic terrain in West Bengal, India, were investigated. Test drilling was conducted at ten sites and grain-size distribution curves (GSDCs) were prepared for 275 geologic samples. Performance evaluation of eight grain-size-analysis (GSA) methods was carried out to estimate the hydraulic conductivity (K) of subsurface formations. Finally, the GSA results were validated against pumping-test data. The GSDCs indicated that shallow aquifer layers are coarser than the deeper aquifer layers (uniformity coefficient 0.19-11.4). Stratigraphy analysis revealed that both shallow and deep aquifers of varying thickness exist at depths 9-40 and 40-79 m, respectively. The mean K estimates by the GSA methods are 3.62-292.86 m/day for shallow aquifer layers and 0.97-209.93 m/day for the deeper aquifer layers, suggesting significant aquifer heterogeneity. Pumping-test data indicated that the deeper aquifers are leaky confined with transmissivity 122.69-693.79 m2/day, storage coefficient 1.01 × 10-7-2.13 × 10-4 and leakance 2.01 × 10-7-34.56 × 10-2 day-1. Although the K values yielded by the GSA methods are generally larger than those obtained from the pumping tests, the Slichter, Harleman and US Bureau Reclamation (USBR) GSA methods yielded reasonable values at most of the sites (1-3 times higher than K estimates by the pumping-test method). In conclusion, more reliable aquifers exist at deeper depths that can be tapped for dependable water supply. GSA methods such as Slichter, Harleman and USBR can be used for the preliminary assessment of K in lateritic terrains in the absence of reliable field methods.

  7. Development and application of 3-D fractal reservoir model based on collage theorem

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I.K.; Kim, K.S.; Sung, W.M. [Hanyang Univ., Seoul (Korea, Republic of)

    1995-04-30

    Reservoir characterization is the essential process to accurately evaluate the reservoir and has been conducted by geostatistical method, SRA algorithm, and etc. The characterized distribution of heterogeneous property by these methods shows randomly distributed phenomena, and does not present anomalous shape of property variation at discontinued space as compared with the observed shape in nature. This study proposed a new algorithm of fractal concept based on collage theorem, which can virtually present not only geometric shape of irregular and anomalous pore structures or coastlines, but also property variation for discontinuously observed data. With a basis of fractal concept, three dimensional fractal reservoir model was developed to more accurately characterize the heterogeneous reservoir. We performed analysis of pre-predictable hypothetically observed permeability data by using the fractal reservoir model. From the results, we can recognize that permeability distributions in the areal view or the cross-sectional view were consistent with the observed data. (author). 8 refs., 1 tab., 6 figs.

  8. Application of the ensemble Kalman filter for characterization and history matching of unconventional oil reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Chitralekha, S.B.; Trivedi, J.J.; Shah, S.L. [Alberta Univ., Edmonton, AB (Canada)

    2010-07-01

    The ensemble Kalman filter (EnKF) was used to continuously update and history match the petroleum reservoir characteristics of 2 unconventional oil reservoir models, notably (1) a highly heterogenous black oil reservoir model, and (2) a heterogenous steam assisted gravity drainage (SAGD) reservoir model. The method was used to sequentially update the spatial properties of the reservoir models through the integration of dynamic production data. Monte Carlo simulations of the model ensembles were used. The method considered production uncertainty by using error covariance matrices for measurement and state vectors. Results of the study demonstrated the advantages of using a localized EnKF for effective history matching. Significant computational time was saved by running the ensemble simulations on independent processors in a parallel mode. 28 refs., 16 figs.

  9. Groundwater salinity and hydrochemical processes in the volcano-sedimentary aquifer of La Aldea, Gran Canaria, Canary Islands, Spain.

    Science.gov (United States)

    Cruz-Fuentes, Tatiana; Cabrera, María del Carmen; Heredia, Javier; Custodio, Emilio

    2014-06-15

    The origin of the groundwater salinity and hydrochemical conditions of a 44km(2) volcano-sedimentary aquifer in the semi-arid to arid La Aldea Valley (western Gran Canaria, Spain) has been studied, using major physical and chemical components. Current aquifer recharge is mainly the result of irrigation return flows and secondarily that of rainfall infiltration. Graphical, multivariate statistical and modeling tools have been applied in order to improve the hydrogeological conceptual model and identify the natural and anthropogenic factors controlling groundwater salinity. Groundwater ranges from Na-Cl-HCO3 type for moderate salinity water to Na-Mg-Cl-SO4 type for high salinity water. This is mainly the result of atmospheric airborne salt deposition; silicate weathering, and recharge incorporating irrigation return flows. High evapotranspiration produces significant evapo-concentration leading to relative high groundwater salinity in the area. Under average conditions, about 70% of the water used for intensive agricultural exploitation in the valley comes from three low salinity water runoff storage reservoirs upstream, out of the area, while the remaining 30% derives from groundwater. The main alluvial aquifer behaves as a short turnover time reservoir that adds to the surface waters to complement irrigation water supply in dry periods, when it reaches 70% of irrigation water requirements. The high seasonality and intra-annual variability of water demand for irrigation press on decision making on aquifer use by a large number of aquifer users acting on their own. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Permeability model of tight reservoir sandstones combining core-plug and miniperm analysis of drillcore; longyearbyen co2lab, Svalbard

    NARCIS (Netherlands)

    Magnabosco, Cara; Braathen, Alvar; Ogata, Kei

    2014-01-01

    Permeability measurements in Mesozoic, low-permeability sandstone units within the strata cored in seven drillholes near Longyearbyen, Svalbard, have been analysed to assess the presence of aquifers and their potentials as reservoirs for the storage of carbon dioxide. These targeted sandstones are

  11. unconventional natural gas reservoirs

    International Nuclear Information System (INIS)

    Correa G, Tomas F; Osorio, Nelson; Restrepo R, Dora P

    2009-01-01

    This work is an exploration about different unconventional gas reservoirs worldwide: coal bed methane, tight gas, shale gas and gas hydrate? describing aspects such as definition, reserves, production methods, environmental issues and economics. The overview also mentioned preliminary studies about these sources in Colombia.

  12. Parallel reservoir simulator computations

    International Nuclear Information System (INIS)

    Hemanth-Kumar, K.; Young, L.C.

    1995-01-01

    The adaptation of a reservoir simulator for parallel computations is described. The simulator was originally designed for vector processors. It performs approximately 99% of its calculations in vector/parallel mode and relative to scalar calculations it achieves speedups of 65 and 81 for black oil and EOS simulations, respectively on the CRAY C-90

  13. Application of advanced reservoir characterization, simulation and production optimization strategies to maximize recovery in slope and basin clastic reservoirs, West Texas (Delaware Basin). Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, S.P.; Asquith, G.B.; Barton, M.D.; Cole, A.G.; Gogas, J.; Malik, M.A.; Clift, S.J.; Guzman, J.I.

    1997-11-01

    The objective of this project is to demonstrate that detailed reservoir characterization of slope and basin clastic reservoirs in sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost-effective way to recover a higher percentage of the original oil in place through strategic placement of infill wells and geologically based field development. This project involves reservoir characterization of two Late Permian slope and basin clastic reservoirs in the Delaware Basin, West Texas, followed by a field demonstration in one of the fields. The fields being investigated are Geraldine Ford and Ford West fields in Reeves and Culberson Counties, Texas. Project objectives are divided into two major phases, reservoir characterization and implementation. The objectives of the reservoir characterization phase of the project were to provide a detailed understanding of the architecture and heterogeneity of the two fields, the Ford Geraldine unit and Ford West field. Reservoir characterization utilized 3-D seismic data, high-resolution sequence stratigraphy, subsurface field studies, outcrop characterization, and other techniques. Once reservoir characterized was completed, a pilot area of approximately 1 mi{sup 2} at the northern end of the Ford Geraldine unit was chosen for reservoir simulation. This report summarizes the results of the second year of reservoir characterization.

  14. Characterization of a managed aquifer recharge system using multiple tracers.

    Science.gov (United States)

    Moeck, Christian; Radny, Dirk; Popp, Andrea; Brennwald, Matthias; Stoll, Sebastian; Auckenthaler, Adrian; Berg, Michael; Schirmer, Mario

    2017-12-31

    Knowledge about the residence times of artificially infiltrated water into an aquifer and the resulting flow paths is essential to developing groundwater-management schemes. To obtain this knowledge, a variety of tracers can be used to study residence times and gain information about subsurface processes. Although a variety of tracers exists, their interpretation can differ considerably due to subsurface heterogeneity, underlying assumptions, and sampling and analysis limitations. The current study systematically assesses information gained from seven different tracers during a pumping experiment at a site where drinking water is extracted from an aquifer close to contaminated areas and where groundwater is artificially recharged by infiltrating surface water. We demonstrate that the groundwater residence times estimated using dye and heat tracers are comparable when the thermal retardation for the heat tracer is considered. Furthermore, major ions, acesulfame, and stable isotopes (δ 2 H and δ 18 O) show that mixing of infiltrated water and groundwater coming from the regional flow path occurred and a vertical stratification of the flow system exist. Based on the concentration patterns of dissolved gases (He, Ar, Kr, N 2 , and O 2 ) and chlorinated solvents (e.g., tetrachloroethene), three temporal phases are observed in the ratio between infiltrated water and regional groundwater during the pumping experiment. Variability in this ratio is significantly related to changes in the pumping and infiltration rates. During constant pumping rates, more infiltrated water was extracted, which led to a higher dilution of the regional groundwater. An infiltration interruption caused however, the ratio to change and more regional groundwater is extracted, which led to an increase in all concentrations. The obtained results are discussed for each tracer considered and its strengths and limitations are illustrated. Overall, it is demonstrated that aquifer heterogeneity and

  15. A Statistical Graphical Model of the California Reservoir System

    Science.gov (United States)

    Taeb, A.; Reager, J. T.; Turmon, M.; Chandrasekaran, V.

    2017-11-01

    The recent California drought has highlighted the potential vulnerability of the state's water management infrastructure to multiyear dry intervals. Due to the high complexity of the network, dynamic storage changes in California reservoirs on a state-wide scale have previously been difficult to model using either traditional statistical or physical approaches. Indeed, although there is a significant line of research on exploring models for single (or a small number of) reservoirs, these approaches are not amenable to a system-wide modeling of the California reservoir network due to the spatial and hydrological heterogeneities of the system. In this work, we develop a state-wide statistical graphical model to characterize the dependencies among a collection of 55 major California reservoirs across the state; this model is defined with respect to a graph in which the nodes index reservoirs and the edges specify the relationships or dependencies between reservoirs. We obtain and validate this model in a data-driven manner based on reservoir volumes over the period 2003-2016. A key feature of our framework is a quantification of the effects of external phenomena that influence the entire reservoir network. We further characterize the degree to which physical factors (e.g., state-wide Palmer Drought Severity Index (PDSI), average temperature, snow pack) and economic factors (e.g., consumer price index, number of agricultural workers) explain these external influences. As a consequence of this analysis, we obtain a system-wide health diagnosis of the reservoir network as a function of PDSI.

  16. Dealing with spatial heterogeneity

    Science.gov (United States)

    Marsily, Gh.; Delay, F.; Gonçalvès, J.; Renard, Ph.; Teles, V.; Violette, S.

    2005-03-01

    Heterogeneity can be dealt with by defining homogeneous equivalent properties, known as averaging, or by trying to describe the spatial variability of the rock properties from geologic observations and local measurements. The techniques available for these descriptions are mostly continuous Geostatistical models, or discontinuous facies models such as the Boolean, Indicator or Gaussian-Threshold models and the Markov chain model. These facies models are better suited to treating issues of rock strata connectivity, e.g. buried high permeability channels or low permeability barriers, which greatly affect flow and, above all, transport in aquifers. Genetic models provide new ways to incorporate more geology into the facies description, an approach that has been well developed in the oil industry, but not enough in hydrogeology. The conclusion is that future work should be focused on improving the facies models, comparing them, and designing new in situ testing procedures (including geophysics) that would help identify the facies geometry and properties. A world-wide catalog of aquifer facies geometry and properties, which could combine site genesis and description with methods used to assess the system, would be of great value for practical applications. On peut aborder le problème de l'hétérogénéité en s'efforçant de définir une perméabilité équivalente homogène, par prise de moyenne, ou au contraire en décrivant la variation dans l'espace des propriétés des roches à partir des observations géologiques et des mesures locales. Les techniques disponibles pour une telle description sont soit continues, comme l'approche Géostatistique, soit discontinues, comme les modèles de faciès, Booléens, ou bien par Indicatrices ou Gaussiennes Seuillées, ou enfin Markoviens. Ces modèles de faciès sont mieux capables de prendre en compte la connectivité des strates géologiques, telles que les chenaux enfouis à forte perméabilité, ou au contraire les faci

  17. Interconnectivity between the Superficial Aquifer and the Deep Confined Aquifers of the Gnangara Mound, Western Australia

    International Nuclear Information System (INIS)

    Salama, Ramsis B.

    2005-01-01

    Perth groundwater resources are obtained from three major aquifers that occur beneath the Perth metropolitan area: the Superficial aquifer, Leederville aquifer and Yarragadee aquifer. Each aquifer has a unique seasonal water level pattern controlled by soils, geomorphology and geology. Land use is mainly responsible for variations in recharge; however, the hydraulic properties control aquifer response and water level pattern to a greater degree. Groundwater in the three aquifers is generally of very good quality except in localised areas. Salinity increases with depth and in direction of groundwater flow in the three aquifers. The best water quality is in the Superficial aquifer in the Wanneroo well field area. The geochemistry and stable isotope signatures from the three major aquifers revealed distinct water types that suggest very little hydraulic connection or mixing of waters between these aquifers at the present abstraction and recharge regimes. The results also show that the Leederville and Yarragadee aquifers were recharged during earlier cooler times while the Superficial aquifer is being recharged at present

  18. Direct simulation of groundwater transit-time distributions using the reservoir theory

    Science.gov (United States)

    Etcheverry, David; Perrochet, Pierre

    Groundwater transit times are of interest for the management of water resources, assessment of pollution from non-point sources, and quantitative dating of groundwaters by the use of environmental isotopes. The age of water is the time water has spent in an aquifer since it has entered the system, whereas the transit time is the age of water as it exits the system. Water at the outlet of an aquifer is a mixture of water elements with different transit times, as a consequence of the different flow-line lengths. In this paper, transit-time distributions are calculated by coupling two existing methods, the reservoir theory and a recent age-simulation method. Based on the derivation of the cumulative age distribution over the whole domain, the approach accounts for the whole hydrogeological framework. The method is tested using an analytical example and its applicability illustrated for a regional layered aquifer. Results show the asymmetry and multimodality of the transit-time distribution even in advection-only conditions, due to the aquifer geometry and to the velocity-field heterogeneity. Résumé Les temps de transit des eaux souterraines sont intéressants à connaître pour gérer l'évaluation des ressources en eau dans le cas de pollution à partir de sources non ponctuelles, et aussi pour dater quantitativement les eaux souterraines au moyen des isotopes du milieu. L'âge de l'eau est le temps qu'elle a passé dans un aquifère depuis qu'elle est entrée dans le système, alors que le temps de transit est l'âge de l'eau au moment où elle quitte le système. L'eau à la sortie d'un aquifère est un mélange d'eaux possédant différents temps de transit, du fait des longueurs différentes des lignes de courant suivies. Dans ce papier, les distributions des temps de transit sont calculées en couplant deux méthodes, la théorie du réservoir et une méthode récente de simulation des âges. Basée sur la dérivation de la distribution cumulées des âges sur

  19. Numerical modeling of fracking fluid and methane migration through fault zones in shale gas reservoirs

    Science.gov (United States)

    Taherdangkoo, Reza; Tatomir, Alexandru; Sauter, Martin

    2017-04-01

    Hydraulic fracturing operation in shale gas reservoir has gained growing interest over the last few years. Groundwater contamination is one of the most important environmental concerns that have emerged surrounding shale gas development (Reagan et al., 2015). The potential impacts of hydraulic fracturing could be studied through the possible pathways for subsurface migration of contaminants towards overlying aquifers (Kissinger et al., 2013; Myers, 2012). The intent of this study is to investigate, by means of numerical simulation, two failure scenarios which are based on the presence of a fault zone that penetrates the full thickness of overburden and connect shale gas reservoir to aquifer. Scenario 1 addresses the potential transport of fracturing fluid from the shale into the subsurface. This scenario was modeled with COMSOL Multiphysics software. Scenario 2 deals with the leakage of methane from the reservoir into the overburden. The numerical modeling of this scenario was implemented in DuMux (free and open-source software), discrete fracture model (DFM) simulator (Tatomir, 2012). The modeling results are used to evaluate the influence of several important parameters (reservoir pressure, aquifer-reservoir separation thickness, fault zone inclination, porosity, permeability, etc.) that could affect the fluid transport through the fault zone. Furthermore, we determined the main transport mechanisms and circumstances in which would allow frack fluid or methane migrate through the fault zone into geological layers. The results show that presence of a conductive fault could reduce the contaminant travel time and a significant contaminant leakage, under certain hydraulic conditions, is most likely to occur. Bibliography Kissinger, A., Helmig, R., Ebigbo, A., Class, H., Lange, T., Sauter, M., Heitfeld, M., Klünker, J., Jahnke, W., 2013. Hydraulic fracturing in unconventional gas reservoirs: risks in the geological system, part 2. Environ Earth Sci 70, 3855

  20. Work reservoirs in thermodynamics

    Science.gov (United States)

    Anacleto, Joaquim

    2010-05-01

    We stress the usefulness of the work reservoir in the formalism of thermodynamics, in particular in the context of the first law. To elucidate its usefulness, the formalism is then applied to the Joule expansion and other peculiar and instructive experimental situations, clarifying the concepts of configuration and dissipative work. The ideas and discussions presented in this study are primarily intended for undergraduate students, but they might also be useful to graduate students, researchers and teachers.

  1. Out of sight, but in their minds: Brazil and its neighbours work together to protect one of the world’s largest groundwater reservoirs

    International Nuclear Information System (INIS)

    Jawerth, Nicole

    2015-01-01

    Shrouded in mystery, the future of the largest groundwater reservoir in Latin America once left scientists, academics and politicians in Brazil, Argentina, Paraguay and Uruguay concerned about the fate of their major freshwater resource. Uncovering clues using nuclear techniques, Brazil and its neighbours are now well-acquainted with the Guarani Aquifer and can confidently expect that, with their new protection and sustainable use framework, water from the aquifer will continue to flow for at least another 200 years. Using isotope hydrology, a nuclear technique, the four countries analysed and assessed the aquifer to evaluate the age, origin and evolution of the groundwater, as well as its quality and the risk of contamination.

  2. Variable-density numerical modeling of seawater intrusion in coastal aquifer with well-developed conduits

    Science.gov (United States)

    Xu, Z.; Hu, B. X.

    2015-12-01

    Karst aquifer is an important drinking water supply for nearly 25% of the world's population. Well-developed subground conduit systems usually can be found in a well-developed karst aquifer, as a dual permeability system. Hydraulic characteristics of non-laminar flow in conduits could be significantly different from darcian flow in porous medium; therefore, hybrid model and different governing equations are necessary in numerical modeling of karst hydrogeology. On the other hand, seawater intrusion has been observed and studied for several decades, also become a worldwidely problem due to groundwater over-pumping and rising sea level. The density difference between freshwater and seawater is recognized as the major factor governing the movements of two fluids in coastal aquifer. Several models have been developed to simulate groundwater flow in karst aquifer, but hardly describe seawater intrusion through the conduits without coupling variable density flow and solute transport. In this study, a numerical SEAWAT model has been developed to simulate variable density flow and transport in heterogeneous karst aquifer. High-density seawater is verified to intrude further inland through high permeability conduit network rather than porous medium. The numerical model also predicts the effect of different cases on seawater intrusion in coastal karst aquifer, such as rising sea level, tide stages and freshwater discharge effects. A series of local and global uncertainty analysis have been taken to evaluate the sensitivity of hydraulic conductivity, porosity, groundwater pumping, sea level, salinity and dispersivity. Heterogeneous conduit and porous medium hydraulic characteristics play an important role in groundwater flow and solute transport simulation. Meanwhile, another hybrid model VDFST-CFP model is currently under development to couple turbulent conduit flow and variable density groundwater flow in porous media, which provides a new method and better description in

  3. Water resources of Rockland County, New York, 2005-07, with emphasis on the Newark Basin Bedrock Aquifer

    Science.gov (United States)

    Heisig, Paul M.

    2011-01-01

    Concerns over the state of water resources in Rockland County, NY, prompted an assessment of current (2005-07) conditions. The investigation included a review of all water resources but centered on the Newark basin aquifer, a fractured-bedrock aquifer over which nearly 300,000 people reside. Most concern has been focused on this aquifer because of (1) high summer pumping rates, with occasional entrained-air problems and an unexplained water-level decline at a monitoring well, (2) annual withdrawals that have approached or even exceeded previous estimates of aquifer recharge, and (3) numerous contamination problems that have caused temporary or long-term shutdown of production wells. Public water supply in Rockland County uses three sources of water in roughly equal parts: (1) the Newark basin sedimentary bedrock aquifer, (2) alluvial aquifers along the Ramapo and Mahwah Rivers, and (3) surface waters from Lake DeForest Reservoir and a smaller, new reservoir supply in the Highlands part of the county. Water withdrawals from the alluvial aquifer in the Ramapo River valley and the Lake DeForest Reservoir are subject to water-supply application permits that stipulate minimum flows that must be maintained downstream into New Jersey. There is a need, therefore, at a minimum, to prevent any loss of the bedrock-aquifer resource--to maintain it in terms of both sustainable use and water-quality protection. The framework of the Newark basin bedrock aquifer included characterization of (1) the structure and fracture occurrence associated with the Newark basin strata, (2) the texture and thickness of overlying glacial and alluvial deposits, (3) the presence of the Palisades sill and associated basaltic units on or within the Newark basin strata, and (4) the streams that drain the aquifer system. The greatest concern regarding sustainability of groundwater resources is the aquifer response to the seasonal increase in pumping rates from May through October (an average increase

  4. Carbonate reservoir characterization with lithofacies clustering and porosity prediction

    International Nuclear Information System (INIS)

    Al Moqbel, Abdulrahman; Wang, Yanghua

    2011-01-01

    One of the objectives in reservoir characterization is to quantitatively or semi-quantitatively map the spatial distribution of its heterogeneity and related properties. With the availability of 3D seismic data, artificial neural networks are capable of discovering the nonlinear relationship between seismic attributes and reservoir parameters. For a target carbonate reservoir, we adopt a two-stage approach to conduct characterization. First, we use an unsupervised neural network, the self-organizing map method, to classify the reservoir lithofacies. Then we apply a supervised neural network, the back-propagation algorithm, to quantitatively predict the porosity of the carbonate reservoir. Based on porosity maps at different time levels, we interpret the target reservoir vertically related to three depositional phases corresponding to, respectively, a lowstand system tract before sea water immersion, a highstand system tract when water covers organic deposits and a transition zone for the sea level falling. The highstand system is the most prospective zone, given the organic content deposited during this stage. The transition zone is also another prospective feature in the carbonate depositional system due to local build-ups

  5. [Review on landscape heterogeneity].

    Science.gov (United States)

    Zhao, Yutao; Yu, Xinxiao; Guang, Wenbin

    2002-04-01

    On the base of precedent studies, the occurring mechanism, classification, measurement methods, and the important role of landscape heterogeneity in landscape ecology were reviewed. The inner and outer uncertain factors result in landscape heterogeneity. Landscape heterogeneity has close relations with landscape stability, landscape design, architecture, management and disturbance, scale and ecological diversity in ecology. Complexity of landscape heterogeneity research, non-system of measurement indices and methods, difficulties and limitations of landscape heterogeneity modelling were all discussed respectively. In addition, it is suggested that the theory and methods of ecological complexity should be used to improve landscape heterogeneity research.

  6. Advantageous Reservoir Characterization Technology in Extra Low Permeability Oil Reservoirs

    Directory of Open Access Journals (Sweden)

    Yutian Luo

    2017-01-01

    Full Text Available This paper took extra low permeability reservoirs in Dagang Liujianfang Oilfield as an example and analyzed different types of microscopic pore structures by SEM, casting thin sections fluorescence microscope, and so on. With adoption of rate-controlled mercury penetration, NMR, and some other advanced techniques, based on evaluation parameters, namely, throat radius, volume percentage of mobile fluid, start-up pressure gradient, and clay content, the classification and assessment method of extra low permeability reservoirs was improved and the parameter boundaries of the advantageous reservoirs were established. The physical properties of reservoirs with different depth are different. Clay mineral variation range is 7.0%, and throat radius variation range is 1.81 μm, and start pressure gradient range is 0.23 MPa/m, and movable fluid percentage change range is 17.4%. The class IV reservoirs account for 9.56%, class II reservoirs account for 12.16%, and class III reservoirs account for 78.29%. According to the comparison of different development methods, class II reservoir is most suitable for waterflooding development, and class IV reservoir is most suitable for gas injection development. Taking into account the gas injection in the upper section of the reservoir, the next section of water injection development will achieve the best results.

  7. Evaluation of the operation of Yermasoyia surface and groundwater reservoirs

    International Nuclear Information System (INIS)

    Iacovides, I.S.

    1988-07-01

    The environmental isotope technique has been used in conjunction with hydrochemical methods to study the conjunctive use of surface and groundwater in the Yermasoyia area of Cyprus. The isotopes used in this study are 18 O, 2 H and 3 H. The isotopically enriched water in the Yermasoyia dam is released periodically in order to study the movement of the released water. From the stable isotopes and tritium data, it became evident that two regions can be distinguished in the aquifer, the Upper part and the Delta area. The secondary aquifer on either side of the river valley does not appear to receive any water from the seepage of the dam. The overall tracer average velocity in the aquifer was computed to be 16±3m per day and this is equivalent to a permeability of 160m per day. Water bodies originating from low frequency spills have been identified at the coast on the basis of oxygen-18 and tritium. A successful simulation of the reservoir for 1985 increased the confidence in the water balance and was used to verify the quantities estimated for evaporation and seepage. Refs, figs and tabs

  8. Hydrogeological Conditions of a Crystalline Aquifer: Simulation of Optimal Abstraction Rates under Scenarios of Reduced Recharge

    Science.gov (United States)

    Fynn, Obed Fiifi; Chegbeleh, Larry Pax; Nude, Prosper M.; Asiedu, Daniel K.

    2013-01-01

    A steady state numerical groundwater flow model has been calibrated to characterize the spatial distribution of a key hydraulic parameter in a crystalline aquifer in southwestern Ghana. This was to provide an initial basis for characterizing the hydrogeology of the terrain with a view to assisting in the large scale development of groundwater resources for various uses. The results suggest that the structural entities that control groundwater occurrence in the area are quite heterogeneous in their nature and orientation, ascribing hydraulic conductivity values in the range of 4.5 m/d to over 70 m/d to the simulated aquifer. Aquifer heterogeneities, coupled possibly with topographical trends, have led to the development of five prominent groundwater flowpaths in the area. Estimated groundwater recharge at calibration ranges between 0.25% and 9.13% of the total annual rainfall and appears to hold significant promise for large-scale groundwater development to support irrigation schemes. However, the model suggests that with reduced recharge by up to 30% of the current rates, the system can only sustain increased groundwater abstraction by up to 150% of the current abstraction rates. Prudent management of the resource will require a much more detailed hydrogeological study that identifies all the aquifers in the basin for the assessment of sustainable basin yield. PMID:24453882

  9. Use of high performance computing to examine the effectiveness of aquifer remediation

    International Nuclear Information System (INIS)

    Tompson, A.F.B.; Ashby, S.F.; Falgout, R.D.; Smith, S.G.; Fogwell, T.W.; Loosmore, G.A.

    1994-06-01

    Large-scale simulation of fluid flow and chemical migration is being used to study the effectiveness of pump-and-treat restoration of a contaminated, saturated aquifer. A three-element approach focusing on geostatistical representations of heterogeneous aquifers, high-performance computing strategies for simulating flow, migration, and reaction processes in large three-dimensional systems, and highly-resolved simulations of flow and chemical migration in porous formations will be discussed. Results from a preliminary application of this approach to examine pumping behavior at a real, heterogeneous field site will be presented. Future activities will emphasize parallel computations in larger, dynamic, and nonlinear (two-phase) flow problems as well as improved interpretive methods for defining detailed material property distributions

  10. Contribution to the hydrogeological, geochemical and isotopic study of Ain El Beidha and Merguellil (Kairouan plain) aquifers: Implication for the dam-aquifer relationship

    International Nuclear Information System (INIS)

    Ben Ammar, Safouan

    2007-01-01

    karst before reaching the Kairouan plain aquifer (springs). Groundwater under flow is estimated at 9 M m3 year-1 and the karstic spring flow is evaluated at 10 M m3 year-1. The spring waters show an intermediate isotope composition between dam reservoir water and the upper catchment of Ain el Beidha basin. The contribution of dam water in mixed water (spring) varies between 21 to 66% depending on time. Values from 18O and 2H ratio are well correlated with the karstic spring flow and with the water level in the reservoir. The hydrogeological study helped to understand the hydrodynamic functioning of the Kairouan plain aquifer system and identified a decline of the water table levels (1.5 m year-1). This decrease is explained mainly by over exploitation (4.8 M m3 year-1). The hydrochemical investigation indicated that the rock-water interaction is the main process contributing to the groundwater salinization. All the samples collected in the Merguellil basin are of the main hydrochemical type: Cl-SO4-Na. Stable isotope values measured in the upstream part of plain, closer the dam, differ from other parts of the aquifer, therefore suggesting a significant input from evaporated dam waters mixed with Ain el Beidha groundwater (spring water coming from the karst). This contamination can be observed as far as 7 km downstream. However, isotopic imprint of the previous recharge process (infiltration of wadi floods) are still noticeable. The residence time of the groundwater was estimated by carbon-14 dating that shows variable values of transit velocity of the groundwater ranging from 3.36 to 0.44 m year-1 depending on the groundwater flow and on the lithological variability of the aquifer. (Author).

  11. Modeling the hydrological behavior of a karst spring using a nonlinear reservoir-pipe model

    Science.gov (United States)

    Chang, Yong; Wu, Jichun; Jiang, Guanghui

    2015-08-01

    Karst aquifers are commonly simulated based on conceptual models. However, most karst conceptual models hardly consider the function of turbulent conduits. The conduit network acts as the main draining passage of the karst aquifer and may also have a strong influence on the hydrological processes, especially during storm events. A conceptual model with a nonlinear reservoir and a turbulent pipe (representing the conduit system) in series is proposed according to the basic structure of a typical karst aquifer, to simulate the karst spring. The model indicates whether the spring discharge is influenced by the turbulent pipe; this not only depends on the parameters of the nonlinear reservoir and turbulent pipe, but also depends on the volume of spring discharge itself. Even though the spring discharge is strongly influenced by the turbulent pipe during the storm, this influence decreases with the rainfall intensity and volume of spring discharge. In addition, an `evapotranspiration store' is used to consider the moisture loss through evapotranspiration and to calculate the effective rainfall on the proposed model. Then, this simple conceptual model is used to simulate a karst spring (named S31) near Guilin city, China, with satisfactory results, especially with respect to discharge peaks and recession curves of the spring under storm conditions. The proposed model is also compared with the Vensim model of similar complexity, which has been applied to the same spring catchment. The comparison shows the superiority and better performance of the nonlinear reservoir-pipe model.

  12. Integration of dynamical data in a geostatistical model of reservoir; Integration des donnees dynamiques dans un modele geostatistique de reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Costa Reis, L.

    2001-01-01

    We have developed in this thesis a methodology of integrated characterization of heterogeneous reservoirs, from geologic modeling to history matching. This methodology is applied to the reservoir PBR, situated in Campos Basin, offshore Brazil, which has been producing since June 1979. This work is an extension of two other thesis concerning geologic and geostatistical modeling of the reservoir PBR from well data and seismic information. We extended the geostatistical litho-type model to the whole reservoir by using a particular approach of the non-stationary truncated Gaussian simulation method. This approach facilitated the application of the gradual deformation method to history matching. The main stages of the methodology for dynamic data integration in a geostatistical reservoir model are presented. We constructed a reservoir model and the initial difficulties in the history matching led us to modify some choices in the geological, geostatistical and flow models. These difficulties show the importance of dynamic data integration in reservoir modeling. The petrophysical property assignment within the litho-types was done by using well test data. We used an inversion procedure to evaluate the petrophysical parameters of the litho-types. The up-scaling is a necessary stage to reduce the flow simulation time. We compared several up-scaling methods and we show that the passage from the fine geostatistical model to the coarse flow model should be done very carefully. The choice of the fitting parameter depends on the objective of the study. In the case of the reservoir PBR, where water is injected in order to improve the oil recovery, the water rate of the producing wells is directly related to the reservoir heterogeneity. Thus, the water rate was chosen as the fitting parameter. We obtained significant improvements in the history matching of the reservoir PBR. First, by using a method we have proposed, called patchwork. This method allows us to built a coherent

  13. On aquifer thicknesses and geological complexity affecting fresh/salt groundwater distribution

    Science.gov (United States)

    Zamrsky, Daniel; Oude Essink, Gualbert; Bierkens, Marc

    2017-04-01

    Large coastal populations will face serious issues associated with global sea level rise in the near future. Among those are increased risk of coastal flooding and upconing of old saline groundwater caused by expected regional groundwater overexploitation initiated by growing urbanization. With predictions of rising sea level by 60-100cm by 2100 and a recent study suggesting even much larger changes than previously thought, it is essential to conduct a study to identify the most threatened coastal aquifers worldwide. Previous global studies dealing with salt water intrusion into coastal aquifers only considered homogenous geological conditions. However, literature and local data show a higher degree of heterogeneity. In our study, we consider possible geological scenarios and their impact on the fresh/salt groundwater distribution. The focus is on coastal aquifers that consist of unconsolidated sediments formed during the recent geological times and are underlain by a consolidated bedrock formation. Aquifer thickness and inland extent are the two most important parameters that determine the vulnerability of the coastal aquifer to salt water intrusion. To estimate these two parameters, a method using the latest global geological and elevation datasets is presented. By combining these inputs, we can estimate the slope of a bedrock formation that underlies a coastal aquifer consisting of unconsolidated sediments. Our estimated thicknesses are compared to a validation dataset of open source boreholes and literature information collected over numerous locations worldwide. While our results show that using our method to estimate coastal aquifer (made of unconsolidated sediments) thickness leads to satisfying results, it remains challenging to obtain information about the type of the sediments (gravel, sand, clay) themselves on such a scale. Therefore, we constructed a substantial set of 2D vertical variable-density groundwater flow models perpendicular to the shoreline

  14. Prediction, time variance, and classification of hydraulic response to recharge in two karst aquifers

    Science.gov (United States)

    Long, Andrew J.; Mahler, Barbara J.

    2013-01-01

    Many karst aquifers are rapidly filled and depleted and therefore are likely to be susceptible to changes in short-term climate variability. Here we explore methods that could be applied to model site-specific hydraulic responses, with the intent of simulating these responses to different climate scenarios from high-resolution climate models. We compare hydraulic responses (spring flow, groundwater level, stream base flow, and cave drip) at several sites in two karst aquifers: the Edwards aquifer (Texas, USA) and the Madison aquifer (South Dakota, USA). A lumped-parameter model simulates nonlinear soil moisture changes for estimation of recharge, and a time-variant convolution model simulates the aquifer response to this recharge. Model fit to data is 2.4% better for calibration periods than for validation periods according to the Nash–Sutcliffe coefficient of efficiency, which ranges from 0.53 to 0.94 for validation periods. We use metrics that describe the shapes of the impulse-response functions (IRFs) obtained from convolution modeling to make comparisons in the distribution of response times among sites and between aquifers. Time-variant IRFs were applied to 62% of the sites. Principal component analysis (PCA) of metrics describing the shapes of the IRFs indicates three principal components that together account for 84% of the variability in IRF shape: the first is related to IRF skewness and temporal spread and accounts for 51% of the variability; the second and third largely are related to time-variant properties and together account for 33% of the variability. Sites with IRFs that dominantly comprise exponential curves are separated geographically from those dominantly comprising lognormal curves in both aquifers as a result of spatial heterogeneity. The use of multiple IRF metrics in PCA is a novel method to characterize, compare, and classify the way in which different sites and aquifers respond to recharge. As convolution models are developed for

  15. Prediction, time variance, and classification of hydraulic response to recharge in two karst aquifers

    Directory of Open Access Journals (Sweden)

    A. J. Long

    2013-01-01

    Full Text Available Many karst aquifers are rapidly filled and depleted and therefore are likely to be susceptible to changes in short-term climate variability. Here we explore methods that could be applied to model site-specific hydraulic responses, with the intent of simulating these responses to different climate scenarios from high-resolution climate models. We compare hydraulic responses (spring flow, groundwater level, stream base flow, and cave drip at several sites in two karst aquifers: the Edwards aquifer (Texas, USA and the Madison aquifer (South Dakota, USA. A lumped-parameter model simulates nonlinear soil moisture changes for estimation of recharge, and a time-variant convolution model simulates the aquifer response to this recharge. Model fit to data is 2.4% better for calibration periods than for validation periods according to the Nash–Sutcliffe coefficient of efficiency, which ranges from 0.53 to 0.94 for validation periods. We use metrics that describe the shapes of the impulse-response functions (IRFs obtained from convolution modeling to make comparisons in the distribution of response times among sites and between aquifers. Time-variant IRFs were applied to 62% of the sites. Principal component analysis (PCA of metrics describing the shapes of the IRFs indicates three principal components that together account for 84% of the variability in IRF shape: the first is related to IRF skewness and temporal spread and accounts for 51% of the variability; the second and third largely are related to time-variant properties and together account for 33% of the variability. Sites with IRFs that dominantly comprise exponential curves are separated geographically from those dominantly comprising lognormal curves in both aquifers as a result of spatial heterogeneity. The use of multiple IRF metrics in PCA is a novel method to characterize, compare, and classify the way in which different sites and aquifers respond to recharge. As convolution models are

  16. Differences in microbial community composition between injection and production water samples of water flooding petroleum reservoirs

    Directory of Open Access Journals (Sweden)

    P. K. Gao

    2015-06-01

    Full Text Available Microbial communities in injected water are expected to have significant influence on those of reservoir strata in long-term water flooding petroleum reservoirs. To investigate the similarities and differences in microbial communities in injected water and reservoir strata, high-throughput sequencing of microbial partial 16S rRNA of the water samples collected from the wellhead and downhole of injection wells, and from production wells in a homogeneous sandstone reservoir and a heterogeneous conglomerate reservoir were performed. The results indicate that a small number of microbial populations are shared between the water samples from the injection and production wells in the sandstone reservoir, whereas a large number of microbial populations are shared in the conglomerate reservoir. The bacterial and archaeal communities in the reservoir strata have high concentrations, which are similar to those in the injected water. However, microbial population abundance exhibited large differences between the water samples from the injection and production wells. The number of shared populations reflects the influence of microbial communities in injected water on those in reservoir strata to some extent, and show strong association with the unique variation of reservoir environments.

  17. An evaluation of seepage gains and losses in Indian Creek Reservoir, Ada County, Idaho, April 2010–November 2011

    Science.gov (United States)

    Williams, Marshall L.; Etheridge, Alexandra B.

    2013-01-01

    The U.S. Geological Survey, in cooperation with the Idaho Department of Water Resources, conducted an investigation on Indian Creek Reservoir, a small impoundment in east Ada County, Idaho, to quantify groundwater seepage into and out of the reservoir. Data from the study will assist the Idaho Water Resources Department’s Comprehensive Aquifer Management Planning effort to estimate available water resources in Ada County. Three independent methods were utilized to estimate groundwater seepage: (1) the water-budget method; (2) the seepage-meter method; and (3) the segmented Darcy method. Reservoir seepage was quantified during the periods of April through August 2010 and February through November 2011. With the water-budget method, all measureable sources of inflow to and outflow from the reservoir were quantified, with the exception of groundwater; the water-budget equation was solved for groundwater inflow to or outflow from the reservoir. The seepage-meter method relies on the placement of seepage meters into the bottom sediments of the reservoir for the direct measurement of water flux across the sediment-water interface. The segmented-Darcy method utilizes a combination of water-level measurements in the reservoir and in adjacent near-shore wells to calculate water-table gradients between the wells and the reservoir within defined segments of the reservoir shoreline. The Darcy equation was used to calculate groundwater inflow to and outflow from the reservoir. Water-budget results provided continuous, daily estimates of seepage over the full period of data collection, while the seepage-meter and segmented Darcy methods provided instantaneous estimates of seepage. As a result of these and other difference in methodologies, comparisons of seepage estimates provided by the three methods are considered semi-quantitative. The results of the water-budget derived estimates of seepage indicate seepage to be seasonally variable in terms of the direction and magnitude

  18. Full Waveform Inversion for Reservoir Characterization - A Synthetic Study

    KAUST Repository

    Zabihi Naeini, E.

    2017-05-26

    Most current reservoir-characterization workflows are based on classic amplitude-variation-with-offset (AVO) inversion techniques. Although these methods have generally served us well over the years, here we examine full-waveform inversion (FWI) as an alternative tool for higher-resolution reservoir characterization. An important step in developing reservoir-oriented FWI is the implementation of facies-based rock physics constraints adapted from the classic methods. We show that such constraints can be incorporated into FWI by adding appropriately designed regularization terms to the objective function. The advantages of the proposed algorithm are demonstrated on both isotropic and VTI (transversely isotropic with a vertical symmetry axis) models with pronounced lateral and vertical heterogeneity. The inversion results are explained using the theoretical radiation patterns produced by perturbations in the medium parameters.

  19. A review on hydraulic fracturing of unconventional reservoir

    Directory of Open Access Journals (Sweden)

    Quanshu Li

    2015-03-01

    Full Text Available Hydraulic fracturing is widely accepted and applied to improve the gas recovery in unconventional reservoirs. Unconventional reservoirs to be addressed here are with very low permeability, complicated geological settings and in-situ stress field etc. All of these make the hydraulic fracturing process a challenging task. In order to effectively and economically recover gas from such reservoirs, the initiation and propagation of hydraulic fracturing in the heterogeneous fractured/porous media under such complicated conditions should be mastered. In this paper, some issues related to hydraulic fracturing have been reviewed, including the experimental study, field study and numerical simulation. Finally the existing problems that need to be solved on the subject of hydraulic fracturing have been proposed.

  20. ATES Contribution to the Housing Energy Balance: a Simple Assessment Methodology Contribution du stockage d’énergie thermique en aquifère au bilan énergétique lié à l’habitat : méthodologie d’évaluation rapide

    Directory of Open Access Journals (Sweden)

    Bourbiaux B.

    2011-02-01

    Full Text Available The reduction of Green-House Gas Emissions (GHGE goes through a sum of solutions that need to be tuned to the local context in terms of energy needs and resources, and also to the demand and offer variations with time. The housing heat consumption is particularly concerned as it is seasonal and rarely in phase with the deliverability of alternative or renewable energy sources. This paper studies heat storage in saline untapped aquifers as a solution to overcome the time lag between production and consumption. This process applies to heat networks that supply dense housing complexes. Firstly, a methodology is described to size an Aquifer Thermal Energy Storage (ATES project as a function of the heat production and consumption characteristics on the one hand, and of the recovery factor of the stored heat on the other hand. The major role played by this recovery factor leads to a review of thermal losses of various origins and to a sensitivity study of influent reservoir parameters such as the aquifer thickness, productivity and heterogeneity, for the purpose of aquifer selection and storage project management. La reduction des Gaz a Effet de Serre (GES passe par un ensemble de solutions qui doivent etre adaptees au contexte local des besoins et ressources en energie, ainsi qu’aux variations de l’offre et la demande au cours du temps. Ce constat concerne en particulier la consommation d’energie calorifique destinee a l’habitat. En effet, cette consommation de chaleur est saisonniere et rarement en phase avec la disponibilite des sources d’energie alternatives ou renouvelables. Cet article etudie le stockage de chaleur dans des aquiferes salins inexploites en tant que solution pour pallier ce dephasage entre production et consommation. Ce procede concerne les reseaux de chaleur desservant un habitat concentre. En premier lieu, une methodologie quantitative est decrite pour dimensionner le projet de stockage d’energie thermique en

  1. Predicting salt intrusion into freshwater aquifers resulting from CO2 injection – A study on the influence of conservative assumptions

    DEFF Research Database (Denmark)

    Walter, Lena; Binning, Philip John; Class, Holger

    2013-01-01

    Brine migration and saltwater intrusion into freshwater aquifers are among the hazards which may result from injecting CO2 into deep saline formations. Comprehensive risk assessment should include estimates of the salinization of freshwater aquifers, preferably based on numerical simulation results...... to an underestimation of hazards. This study compares two conceptual model approaches for the numerical simulation of brine-migration scenarios through a vertical fault and salt intrusion into a fresh water aquifer. The first approach calculates salt discharge into freshwater using an immiscible two-phase model......-phase model is applied in the CO2 storage reservoir and spatially coupled to a single-phase (water) two-component (water, salt) model, where salt mass fraction is a variable. A Dirichlet–Neumann technique is used for the coupling conditions at the interface of the two models. The results show...

  2. Production Characteristics with Different Superimposed Modes Using Variogram: A Case Study of a Super-Giant Carbonate Reservoir in the Middle East

    Directory of Open Access Journals (Sweden)

    Chenji Wei

    2017-02-01

    Full Text Available Heterogeneity of permeability is an important factor affecting the production of a carbonate reservoir. How to correctly characterize the heterogeneity of permeability has become a key issue for carbonate reservoir development. In this study, the reservoirs were categorized into four superimposed modes based on the actual logging data from a super-giant heterogeneous carbonate reservoir in the Middle East. A modified permeability formula in terms of the variogram method was presented to reflect the heterogeneity of the reservoirs. Furthermore, the models of oil production and water cut were established and the analytical solutions were obtained. The calculation results show that the present model can predict the productivity of wells with different heterogeneous layers more accurately and rapidly. The larger the varigoram value, the stronger the heterogeneity of the reservoirs, and the faster the decline of production owing to a quicker reduction of formation pressure. With the increase in variogram value, the relative permeability of the oil phase is smaller and the water phase larger, and the water cut becomes larger. This study has provided a quick and reasonable prediction model for heterogeneous reservoir.

  3. Investigating the effect of heterogeneity on infill wells

    Directory of Open Access Journals (Sweden)

    Mahmood Bagheri

    2015-12-01

    Full Text Available Abstract In recent years, improving oil recovery (IOR has become an important subject for the petroleum industry. One IOR method is infill drilling, which improves hydrocarbon recovery from virgin zones of the reservoir. Determining the appropriate location for the infill wells is very challenging and greatly depends on different factors such as the reservoir heterogeneity. This study aims to investigate the effect of reservoir heterogeneity on the location of infill well. In order to characterize the effect of heterogeneity on infill well locations, some geostatistical methods, e.g., sequential gaussian simulation, have been applied to generate various heterogeneity models. In particular, different correlation ranges (R were used to observe the effect of heterogeneity. Results revealed that an increase in correlation ranges will lead to (1 a higher field oil production total, and (2 a faster expansion of the drainage radius which consequently reduced the need for infill wells. The results of this study will help engineers to appropriately design infill drilling schemes.

  4. Ground-Penetrating Radar and Dielectric Characterization of Shallow Reservoir Analogs in Central Texas Carbonates

    Science.gov (United States)

    Mukherjee, Damayanti; Heggy, Essam; Khan, Shuhab D.; Sullivan, Charlotte E.

    2007-10-01

    Lake Georgetown Spillway near Georgetown (Williamson County) in Central Texas exposes Albian rudist communities and associated depositional facies of the Edwards Formation, Fredericksburg Group. Capped by younger dolostones of the same group, they form important analogs for highly productive fresh-water aquifers and hydrocarbon reservoirs in carbonate environments. A 2D ground-penetrating radar (GPR) survey was conducted using a 400 MHz antenna with the Subsurface Interface Radar (SIR-3000) System by GSSI and tied to GPS data. Data constituting a grid were processed and numerical simulation performed for 3D visualization using the software REFLEX. Dielectric measurements of field-collected rock samples were carried out initially under vacuum dried condition and then under controlled amounts of moisture content (considering 100% saturation of pores of each sample after 2 hours of water treatment). For each sample, penetration depths were calculated for antenna frequencies of 100 and 400 MHz assuming GPR signal penetration in a homogeneous layer. This was followed by porosity-permeability measurements along with petrographic and X-ray diffraction studies. Real (ɛ1) and imaginary parts (ɛ2) of the dielectric permittivity (ɛ), when plotted against moisture content, demonstrated a greater range of ɛ-values for more permeable samples. The depths of penetration varied inversely with the permeability of the samples. The processed 2D GPR data and 3D simulation revealed mound structures below the spillway floor, each with a diameter of ~15-20m and a thickness of ~5m. Petrographic studies showed the dominance of mouldic porosity in these carbonates while X-ray diffraction results confirmed calcite and dolomite as the dominant mineralogy, although present in varying proportions. Silica peaks were encountered that possibly represented chert replacements seen in the thin-sections. We thus conclude that different carbonate units can be differentiated in the field by the GPR

  5. Advances in photonic reservoir computing

    Science.gov (United States)

    Van der Sande, Guy; Brunner, Daniel; Soriano, Miguel C.

    2017-05-01

    We review a novel paradigm that has emerged in analogue neuromorphic optical computing. The goal is to implement a reservoir computer in optics, where information is encoded in the intensity and phase of the optical field. Reservoir computing is a bio-inspired approach especially suited for processing time-dependent information. The reservoir's complex and high-dimensional transient response to the input signal is capable of universal computation. The reservoir does not need to be trained, which makes it very well suited for optics. As such, much of the promise of photonic reservoirs lies in their minimal hardware requirements, a tremendous advantage over other hardware-intensive neural network models. We review the two main approaches to optical reservoir computing: networks implemented with multiple discrete optical nodes and the continuous system of a single nonlinear device coupled to delayed feedback.

  6. Scalable and Robust BDDC Preconditioners for Reservoir and Electromagnetics Modeling

    KAUST Repository

    Zampini, S.

    2015-09-13

    The purpose of the study is to show the effectiveness of recent algorithmic advances in Balancing Domain Decomposition by Constraints (BDDC) preconditioners for the solution of elliptic PDEs with highly heterogeneous coefficients, and discretized by means of the finite element method. Applications to large linear systems generated by div- and curl- conforming finite elements discretizations commonly arising in the contexts of modelling reservoirs and electromagnetics will be presented.

  7. Encapsulated microsensors for reservoir interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Eddie Elmer; Aines, Roger D.; Spadaccini, Christopher M.

    2016-03-08

    In one general embodiment, a system includes at least one microsensor configured to detect one or more conditions of a fluidic medium of a reservoir; and a receptacle, wherein the receptacle encapsulates the at least one microsensor. In another general embodiment, a method include injecting the encapsulated at least one microsensor as recited above into a fluidic medium of a reservoir; and detecting one or more conditions of the fluidic medium of the reservoir.

  8. Overview of the Ogallala Aquifer Program

    Science.gov (United States)

    Irrigation increased markedly on the Southern High Plains during the second half of the 20th century, drawing water primarily from the Ogallala Aquifer. During this time, irrigation sustained regional farm incomes and rural economies. Withdrawals from the aquifer, however, have exceeded recharge, re...

  9. Hydrogeochemical analysis for Tasuj plain aquifer, Iran

    Indian Academy of Sciences (India)

    Therefore, groundwater quality monitoring and protection are essential to sustain the Tasuj plain aquifer. For this purpose, a fundamental understanding of hydrogeochemi- cal processes and hydrogeological conditions for an aquifer system is important (Adams et al. 2001;. Keywords. Graphical method; hydrogeochemistry ...

  10. Geohydrology of the Cerro Prieto geothermal aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez R, J.; de la Pena L, A.

    1981-01-01

    The most recent information on the Cerro Prieto geothermal aquifer is summarized, with special emphasis on the initial production zone where the wells completed in the Alpha aquifer are located. These wells produce steam for power plant units 1 and 2. Brief comments also are made on the Beta aquifer, which underlies the Alpha aquifer in the Cerro Prieto I area and which extends to the east to what is known as the Cerro Prieto II and Cerro Prieto III areas. The location of the area studied is shown. The Alpha and Beta aquifers differ in their mineralogy and cementing mineral composition, temperatures, and piezometric levels. The difference in piezometric levels indicates that there is no local communication between the two aquifers. This situation has been verified by a well interference test, using well E-1 as a producer in the Beta aquifer and well M-46 as the observation well in the Alpha aquifer. No interference between them was observed. Information on the geology, geohydrology, and geochemistry of Cerro Prieto is presented.

  11. Geological and production characteristics of strandplain/barrier island reservoirs in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Cole, E.L.; Fowler, M.; Jackson, S.; Madden, M.P.; Reeves, T.K.; Salamy, S.P.; Young, M.A.

    1994-12-01

    The Department of Energy`s (DOE`s) primary mission in the oil research program is to maximize the economically and environmentally sound recovery of oil from domestic reservoirs and to preserve access to this resource. The Oil Recovery Field Demonstration Program supports DOE`s mission through cost-shared demonstrations of improved Oil Recovery (IOR) processes and reservoir characterization methods. In the past 3 years, the DOE has issued Program Opportunity Notices (PONs) seeking cost-shared proposals for the three highest priority, geologically defined reservoir classes. The classes have been prioritized based on resource size and risk of abandonment. This document defines the geologic, reservoir, and production characteristics of the fourth reservoir class, strandplain/barrier islands. Knowledge of the geological factors and processes that control formation and preservation of reservoir deposits, external and internal reservoir heterogeneities, reservoir characterization methodology, and IOR process application can be used to increase production of the remaining oil-in-place (IOR) in Class 4 reservoirs. Knowledge of heterogeneities that inhibit or block fluid flow is particularly critical. Using the TORIS database of 330 of the largest strandplain/barrier island reservoirs and its predictive and economic models, the recovery potential which could result from future application of IOR technologies to Class 4 reservoirs was estimated to be between 1.0 and 4.3 billion barrels, depending on oil price and the level of technology advancement. The analysis indicated that this potential could be realized through (1) infill drilling alone and in combination with polymer flooding and profile modification, (2) chemical flooding (sufactant), and (3) thermal processes. Most of this future potential is in Texas, Oklahoma, and the Rocky Mountain region. Approximately two-thirds of the potentially recoverable resource is at risk of abandonment by the year 2000.

  12. [Summer Greenhouse Gases Exchange Flux Across Water-air Interface in Three Water Reservoirs Located in Different Geologic Setting in Guangxi, China].

    Science.gov (United States)

    Li, Jian-hong; Pu, Jun-bing; Sun, Ping-an; Yuan, Dao-xian; Liu, Wen; Zhang, Tao; Mo, Xue

    2015-11-01

    efflux in karst groundwater-fed reservoir was much higher than that of reservoir in non-karst area due to groundwater of DIC-rich input from karst aquifer and thermal stratification.

  13. Economics of Managed Aquifer Recharge

    Directory of Open Access Journals (Sweden)

    Robert G. Maliva

    2014-05-01

    Full Text Available Managed aquifer recharge (MAR technologies can provide a variety of water resources management benefits by increasing the volume of stored water and improving water quality through natural aquifer treatment processes. Implementation of MAR is often hampered by the absence of a clear economic case for the investment to construct and operate the systems. Economic feasibility can be evaluated using cost benefit analysis (CBA, with the challenge of monetizing benefits. The value of water stored or treated by MAR systems can be evaluated by direct and indirect measures of willingness to pay including market price, alternative cost, value marginal product, damage cost avoided, and contingent value methods. CBAs need to incorporate potential risks and uncertainties, such as failure to meet performance objectives. MAR projects involving high value uses, such as potable supply, tend to be economically feasible provided that local hydrogeologic conditions are favorable. They need to have low construction and operational costs for lesser value uses, such as some irrigation. Such systems should therefore be financed by project beneficiaries, but dichotomies may exist between beneficiaries and payers. Hence, MAR projects in developing countries may be economically viable, but external support is often required because of limited local financial resources.

  14. Underground hydrogen storage. Final report. [Salt caverns, excavated caverns, aquifers and depleted fields

    Energy Technology Data Exchange (ETDEWEB)

    Foh, S.; Novil, M.; Rockar, E.; Randolph, P.

    1979-12-01

    The technical and economic feasibility of storing hydrogen in underground storage reservoirs is evaluated. The past and present technology of storing gases, primarily natural gas is reviewed. Four types of reservoirs are examined: salt caverns, excavated caverns, aquifers, and depleted fields. A technical investigation of hydrogen properties reveals that only hydrogen embrittlement places a limit on the underground storage by hydrogen. This constraint will limit reservoir pressures to 1200 psi or less. A model was developed to determine economic feasibility. After making reasonable assumptions that a utility might make in determining whether to proceed with a new storage operation, the model was tested and verified on natural gas storage. A parameteric analysis was made on some of the input parameters of the model to determine the sensitivity of the cost of service to them. Once the model was verified it was used to compute the cost of service of storing hydrogen in the four reservoir types. The costs of service for hydrogen storage ranged from 26 to 150% of the cost of the gas stored. The study concludes that it is now both safe and economic to store hydrogen in underground reservoirs.

  15. Regional Risk Assessment for climate change impacts on coastal aquifers.

    Science.gov (United States)

    Iyalomhe, F; Rizzi, J; Pasini, S; Torresan, S; Critto, A; Marcomini, A

    2015-12-15

    Coastal aquifers have been identified as particularly vulnerable to impacts on water quantity and quality due to the high density of socio-economic activities and human assets in coastal regions and to the projected rising sea levels, contributing to the process of saltwater intrusion. This paper proposes a Regional Risk Assessment (RRA) methodology integrated with a chain of numerical models to evaluate potential climate change-related impacts on coastal aquifers and linked natural and human systems (i.e., wells, river, agricultural areas, lakes, forests and semi-natural environments). The RRA methodology employs Multi Criteria Decision Analysis methods and Geographic Information Systems functionalities to integrate heterogeneous spatial data on hazard, susceptibility and risk for saltwater intrusion and groundwater level variation. The proposed approach was applied on the Esino River basin (Italy) using future climate hazard scenarios based on a chain of climate, hydrological, hydraulic and groundwater system models running at different spatial scales. Models were forced with the IPCC SRES A1B emission scenario for the period 2071-2100 over four seasons (i.e., winter, spring, summer and autumn). Results indicate that in future seasons, climate change will cause few impacts on the lower Esino River valley. Groundwater level decrease will have limited effects: agricultural areas, forests and semi-natural environments will be at risk only in a region close to the coastline which covers less than 5% of the total surface of the considered receptors; less than 3.5% of the wells will be exposed in the worst scenario. Saltwater intrusion impact in future scenarios will be restricted to a narrow region close to the coastline (only few hundred meters), and thus it is expected to have very limited effects on the Esino coastal aquifer with no consequences on the considered natural and human systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Reservoir Simulations of Low-Temperature Geothermal Reservoirs

    Science.gov (United States)

    Bedre, Madhur Ganesh

    The eastern United States generally has lower temperature gradients than the western United States. However, West Virginia, in particular, has higher temperature gradients compared to other eastern states. A recent study at Southern Methodist University by Blackwell et al. has shown the presence of a hot spot in the eastern part of West Virginia with temperatures reaching 150°C at a depth of between 4.5 and 5 km. This thesis work examines similar reservoirs at a depth of around 5 km resembling the geology of West Virginia, USA. The temperature gradients used are in accordance with the SMU study. In order to assess the effects of geothermal reservoir conditions on the lifetime of a low-temperature geothermal system, a sensitivity analysis study was performed on following seven natural and human-controlled parameters within a geothermal reservoir: reservoir temperature, injection fluid temperature, injection flow rate, porosity, rock thermal conductivity, water loss (%) and well spacing. This sensitivity analysis is completed by using ‘One factor at a time method (OFAT)’ and ‘Plackett-Burman design’ methods. The data used for this study was obtained by carrying out the reservoir simulations using TOUGH2 simulator. The second part of this work is to create a database of thermal potential and time-dependant reservoir conditions for low-temperature geothermal reservoirs by studying a number of possible scenarios. Variations in the parameters identified in sensitivity analysis study are used to expand the scope of database. Main results include the thermal potential of reservoir, pressure and temperature profile of the reservoir over its operational life (30 years for this study), the plant capacity and required pumping power. The results of this database will help the supply curves calculations for low-temperature geothermal reservoirs in the United States, which is the long term goal of the work being done by the geothermal research group under Dr. Anderson at

  17. Numerical studies of CO2 and brine leakage into a shallow aquifer through an open wellbore

    Science.gov (United States)

    Wang, Jingrui; Hu, Litang; Pan, Lehua; Zhang, Keni

    2018-03-01

    Industrial-scale geological storage of CO2 in saline aquifers may cause CO2 and brine leakage from abandoned wells into shallow fresh aquifers. This leakage problem involves the flow dynamics in both the wellbore and the storage reservoir. T2Well/ECO2N, a coupled wellbore-reservoir flow simulator, was used to analyze CO2 and brine leakage under different conditions with a hypothetical simulation model in water-CO2-brine systems. Parametric studies on CO2 and brine leakage, including the salinity, excess pore pressure (EPP) and initially dissolved CO2 mass fraction, are conducted to understand the mechanism of CO2 migration. The results show that brine leakage rates increase proportionally with EPP and inversely with the salinity when EPP varies from 0.5 to 1.5 MPa; however, there is no CO2 leakage into the shallow freshwater aquifer if EPP is less than 0.5 MPa. The dissolved CO2 mass fraction shows an important influence on the CO2 plume, as part of the dissolved CO2 becomes a free phase. Scenario simulation shows that the gas lifting effect will significantly increase the brine leakage rate into the shallow freshwater aquifer under the scenario of 3.89% dissolved CO2 mass fraction. The equivalent porous media (EPM) approach used to model the wellbore flow has been evaluated and results show that the EPM approach could either under- or over-estimate brine leakage rates under most scenarios. The discrepancies become more significant if a free CO2 phase evolves. Therefore, a model that can correctly describe the complex flow dynamics in the wellbore is necessary for investigating the leakage problems.

  18. HESS Opinions: Linking Darcy's equation to the linear reservoir

    Science.gov (United States)

    Savenije, Hubert H. G.

    2018-03-01

    In groundwater hydrology, two simple linear equations exist describing the relation between groundwater flow and the gradient driving it: Darcy's equation and the linear reservoir. Both equations are empirical and straightforward, but work at different scales: Darcy's equation at the laboratory scale and the linear reservoir at the watershed scale. Although at first sight they appear similar, it is not trivial to upscale Darcy's equation to the watershed scale without detailed knowledge of the structure or shape of the underlying aquifers. This paper shows that these two equations, combined by the water balance, are indeed identical provided there is equal resistance in space for water entering the subsurface network. This implies that groundwater systems make use of an efficient drainage network, a mostly invisible pattern that has evolved over geological timescales. This drainage network provides equally distributed resistance for water to access the system, connecting the active groundwater body to the stream, much like a leaf is organized to provide all stomata access to moisture at equal resistance. As a result, the timescale of the linear reservoir appears to be inversely proportional to Darcy's conductance, the proportionality being the product of the porosity and the resistance to entering the drainage network. The main question remaining is which physical law lies behind pattern formation in groundwater systems, evolving in a way that resistance to drainage is constant in space. But that is a fundamental question that is equally relevant for understanding the hydraulic properties of leaf veins in plants or of blood veins in animals.

  19. Lack of inhibiting effect of oil emplacement on quartz cementation: Evidence from Cambrian reservoir sandstones, Paleozoic Baltic Basin

    DEFF Research Database (Denmark)

    Molenaar, Nicolaas; Cyziene, Jolanta; Sliaupa, Saulius

    2008-01-01

    , including sandstone architecture, i.e., distribution of shales within the sandstone bodies, and sandstone thickness. Heterogeneity is inherent to sandstone architecture and to the fact that silica for quartz cementation is derived from heterogeneously distributed local pressure solution. Models predicting...... reservoir properties should encompass facies and architecture as important independent factors....

  20. Characterizing flow pathways in a sandstone aquifer at multiple depths

    Science.gov (United States)

    Medici, Giacomo; West, Jared; Mountney, Nigel

    2017-04-01

    Sandstone aquifers are commonly assumed to represent porous media characterized by a permeable matrix. However, such aquifers may be heavily fractured where rock properties and timing of deformation favour brittle failure and crack opening. In many aquifer types, fractures associated with faults, bedding planes and stratabound joints represent preferential pathways for fluids and contaminants. This presentation reports well-test results and outcrop-scale studies that reveal how strongly lithified siliciclastic rocks may be entirely dominated by fracture flow at shallow depths (≤ 150 m), similar to limestone and crystalline aquifers. The Triassic St Bees Sandstone Formation of the UK East Irish Sea Basin represents an optimum succession for study of the influence of both sedimentary and tectonic aquifer heterogeneities in a strongly lithified sandstone aquifer-type. This sedimentary succession of fluvial origin accumulated in rapidly subsiding basins, which typically favour preservation of complete depositional cycles, including fine-grained mudstone and silty sandstone layers of floodplain origin interbedded with sandstone-dominated fluvial channel deposits. Vertical joints in the St Bees Sandstone Formation form a pervasive stratabound system whereby joints terminate at bedding-parallel discontinuities. Additionally, normal faults are present through the succession and record development of open-fractures in their damage zones. Here, the shallow aquifer (depth ≤150 m BGL) was characterized in outcrop and well tests. Fluid temperature, conductivity and flow-velocity logs record inflows and outflows from normal faults, as well as from pervasive bed-parallel fractures. Quantitative flow logging analyses in boreholes that cut fault planes indicate that zones of fault-related open fractures typically represent ˜ 50% of well transmissivity. The remaining flow component is dominated by bed-parallel fractures. However, such sub-horizontal fractures become the

  1. Evaluation of potential gas clogging associated with managed aquifer recharge from a spreading basin, southwestern Utah, U.S.A.

    Science.gov (United States)

    Heilweil, Victor M.; Marston, Thomas

    2013-01-01

    Sand Hollow Reservoir in southwestern Utah, USA, is operated for both surface-water storage and managed aquifer recharge via infiltration from surface basin spreading to the underlying Navajo Sandstone. The total volume of estimated recharge from 2002 through 2011 was 131 Mm3., resulting in groundwater levels rising as much as 40 m. Hydraulic and hydrochemical data from the reservoir and various monitoring wells in Sand Hollow were used to evaluate the timing and location or reservoir recharge moving through the aquifer, along either potential clogging from trapped gases in pore throats, siltation, or algal mats. Several hyrdochemical tracers indicated this recharge had arrived at four monitoring wells located within about 300 m of the reservoir by 2012. At these wells, peak total dissolved-gas pressures exceeded two atmospheres (>1,500 mm mercury) and dissolved oxygen approached three times atmospherically equilibrated concentrations (>25 mg/L). these field parameters indicate that large amounts of gas trapped in pore spaces beneath the water table have dissolved. Lesser but notable increases in these dissolved-gas parameters (without increases in other indicators such as chloride-to-bromide ratios) at monitoring wells farther away (>300 m) indicate moderate amounts of in-situ sir entrapment and dissolution caused by the rise in regional groundwater levels. This is confirmed by hydrochemical difference between these sites and wells closer to the reservoir where recharge had already arrived. As the reservoir was being filled by 2002, managed aquifer recharge rates were initially very high (1.5 x 10-4 cm/s) with the vadose zone becoming saturated beneath and surrounding the reservoir. These rates declined to less than 3.5 x 10-6 cm/s during 2008. The 2002-08 decrease was likely associated with a declining regional hydraulic gradient and clogging. Increasing recharge rates during mid-2009 through 2010 may have been partly caused by dissolution of air bubbles

  2. Analytical solutions for recession analyses of sloping aquifers - applicability on relict rock glaciers in alpine catchments

    Science.gov (United States)

    Pauritsch, Marcus; Birk, Steffen; Hergarten, Stefan; Kellerer-Pirklbauer, Andreas; Winkler, Gerfried

    2014-05-01

    model was then compared to the analytical solution based on the one dimensional Boussinesq equation for unconfined flow in sloping aquifers. Field observations as well as results from the numerical model suggest that the rock glacier has a complex internal structure with zones of low hydraulic conductivity and a high conductive layer on top. The analytical solution attempts to represent this heterogeneous aquifer by an equivalent homogeneous medium. However, as the relative contribution of the different aquifer components varies throughout the recession, the parameter estimates are not easily interpreted in terms of actual aquifer properties. Employing analytical solutions for recession analysis in this type of setting therefore requires a sound understanding of the internal structure and its influence on the flow and storage processes within the rock glacier.

  3. Make use of dynamic data - a constraint based EnKF for SAGD reservoir characterization and production management

    Energy Technology Data Exchange (ETDEWEB)

    Gul, Ali; Nejadi, Siavash; Shah, Sirish L; Trivedi, Japan J [University of Alberta (Canada)

    2011-07-01

    Steam assisted gravity drainage (SAGD) is a thermal recovery process widely used in the Athabasca oil sands, the largest bitumen reservoir in the world. In order to optimize the process, an accurate characterization of the reservoir heterogeneity and identification of the potential steam barriers is necessary. The aim of this paper was to assess the potential of constraint based ensemble Kalman filter (EnKF) approach with localization to address these issues. Data records from observation, production and injection wells were used and the method was tested on a twin well SAGD process and a single well SAGD model with hybrid grids. Results showed a better characterization of the reservoir's heterogeneity and a reduction of uncertainty in the prediction of steam chamber growth. The technique developed herein provides accurate information about the steam chamber and the reservoir heterogeneity and can be used for planning and decision making of other field development strategies.

  4. A review of reservoir desiltation

    DEFF Research Database (Denmark)

    Brandt, Anders

    2000-01-01

    physical geography, hydrology, desilation efficiency, reservoir flushing, density-current venting, sediment slucing, erosion pattern, downstream effects, flow characteristics, sedimentation......physical geography, hydrology, desilation efficiency, reservoir flushing, density-current venting, sediment slucing, erosion pattern, downstream effects, flow characteristics, sedimentation...

  5. Reservoir sedimentation; a literature survey

    NARCIS (Netherlands)

    Sloff, C.J.

    1991-01-01

    A survey of literature is made on reservoir sedimentation, one of the most threatening processes for world-wide reservoir performance. The sedimentation processes, their impacts, and their controlling factors are assessed from a hydraulic engineering point of view with special emphasis on

  6. FRACTURED PETROLEUM RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Abbas Firoozabadi

    1999-06-11

    The four chapters that are described in this report cover a variety of subjects that not only give insight into the understanding of multiphase flow in fractured porous media, but they provide also major contribution towards the understanding of flow processes with in-situ phase formation. In the following, a summary of all the chapters will be provided. Chapter I addresses issues related to water injection in water-wet fractured porous media. There are two parts in this chapter. Part I covers extensive set of measurements for water injection in water-wet fractured porous media. Both single matrix block and multiple matrix blocks tests are covered. There are two major findings from these experiments: (1) co-current imbibition can be more efficient than counter-current imbibition due to lower residual oil saturation and higher oil mobility, and (2) tight fractured porous media can be more efficient than a permeable porous media when subjected to water injection. These findings are directly related to the type of tests one can perform in the laboratory and to decide on the fate of water injection in fractured reservoirs. Part II of Chapter I presents modeling of water injection in water-wet fractured media by modifying the Buckley-Leverett Theory. A major element of the new model is the multiplication of the transfer flux by the fractured saturation with a power of 1/2. This simple model can account for both co-current and counter-current imbibition and computationally it is very efficient. It can be orders of magnitude faster than a conventional dual-porosity model. Part II also presents the results of water injection tests in very tight rocks of some 0.01 md permeability. Oil recovery from water imbibition tests from such at tight rock can be as high as 25 percent. Chapter II discusses solution gas-drive for cold production from heavy-oil reservoirs. The impetus for this work is the study of new gas phase formation from in-situ process which can be significantly

  7. Reservoir engineering and hydrogeology

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Summaries are included which show advances in the following areas: fractured porous media, flow in single fractures or networks of fractures, hydrothermal flow, hydromechanical effects, hydrochemical processes, unsaturated-saturated systems, and multiphase multicomponent flows. The main thrust of these efforts is to understand the movement of mass and energy through rocks. This has involved treating fracture rock masses in which the flow phenomena within both the fractures and the matrix must be investigated. Studies also address the complex coupling between aspects of thermal, hydraulic, and mechanical processes associated with a nuclear waste repository in a fractured rock medium. In all these projects, both numerical modeling and simulation, as well as field studies, were employed. In the theoretical area, a basic understanding of multiphase flow, nonisothermal unsaturated behavior, and new numerical methods have been developed. The field work has involved reservoir testing, data analysis, and case histories at a number of geothermal projects

  8. Chalk as a reservoir

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke

    basin, so stylolite formation in the chalk is controlled by effective burial stress. The stylolites are zones of calcite dissolution and probably are the source of calcite for porefilling cementation which is typical in water zone chalk and also affect the reservoirs to different extent. The relatively...... 50% calcite, leaving the remaining internal surface to the fine grained silica and clay. The high specific surface of these components causes clay- and silica rich intervals to have high irreducible water saturation. Although chalks typically are found to be water wet, chalk with mixed wettability...... stabilizes chemically by recrystallization. This process requires energy and is promoted by temperature. This recrystallization in principle does not influence porosity, but only specific surface, which decreases during recrystallization, causing permeability to increase. The central North Sea is a warm...

  9. Pacifiers: a microbial reservoir.

    Science.gov (United States)

    Comina, Elodie; Marion, Karine; Renaud, François N R; Dore, Jeanne; Bergeron, Emmanuelle; Freney, Jean

    2006-12-01

    The permanent contact between the nipple part of pacifiers and the oral microflora offers ideal conditions for the development of biofilms. This study assessed the microbial contamination on the surface of 25 used pacifier nipples provided by day-care centers. Nine were made of silicone and 16 were made of latex. The biofilm was quantified using direct staining and microscopic observations followed by scraping and microorganism counting. The presence of a biofilm was confirmed on 80% of the pacifier nipples studied. This biofilm was mature for 36% of them. Latex pacifier nipples were more contaminated than silicone ones. The two main genera isolated were Staphylococcus and Candida. Our results confirm that nipples can be seen as potential reservoirs of infections. However, pacifiers do have some advantages; in particular, the potential protection they afford against sudden infant death syndrome. Strict rules of hygiene and an efficient antibiofilm cleaning protocol should be established to answer the worries of parents concerning the safety of pacifiers.

  10. Real-time reservoir geological model updating using the hybrid EnKF and geostatistical technique

    Energy Technology Data Exchange (ETDEWEB)

    Li, H.; Chen, S.; Yang, D. [Regina Univ., SK (Canada). Petroleum Technology Research Centre

    2008-07-01

    Reservoir simulation plays an important role in modern reservoir management. Multiple geological models are needed in order to analyze the uncertainty of a given reservoir development scenario. Ideally, dynamic data should be incorporated into a reservoir geological model. This can be done by using history matching and tuning the model to match the past performance of reservoir history. This study proposed an assisted history matching technique to accelerate and improve the matching process. The Ensemble Kalman Filter (EnKF) technique, which is an efficient assisted history matching method, was integrated with a conditional geostatistical simulation technique to dynamically update reservoir geological models. The updated models were constrained to dynamic data, such as reservoir pressure and fluid saturations, and approaches geologically realistic at each time step by using the EnKF technique. The new technique was successfully applied in a heterogeneous synthetic reservoir. The uncertainty of the reservoir characterization was significantly reduced. More accurate forecasts were obtained from the updated models. 3 refs., 2 figs.

  11. Microbial Life in an Underground Gas Storage Reservoir

    Science.gov (United States)

    Bombach, Petra; van Almsick, Tobias; Richnow, Hans H.; Zenner, Matthias; Krüger, Martin

    2015-04-01

    While underground gas storage is technically well established for decades, the presence and activity of microorganisms in underground gas reservoirs have still hardly been explored today. Microbial life in underground gas reservoirs is controlled by moderate to high temperatures, elevated pressures, the availability of essential inorganic nutrients, and the availability of appropriate chemical energy sources. Microbial activity may affect the geochemical conditions and the gas composition in an underground reservoir by selective removal of anorganic and organic components from the stored gas and the formation water as well as by generation of metabolic products. From an economic point of view, microbial activities can lead to a loss of stored gas accompanied by a pressure decline in the reservoir, damage of technical equipment by biocorrosion, clogging processes through precipitates and biomass accumulation, and reservoir souring due to a deterioration of the gas quality. We present here results from molecular and cultivation-based methods to characterize microbial communities inhabiting a porous rock gas storage reservoir located in Southern Germany. Four reservoir water samples were obtained from three different geological horizons characterized by an ambient reservoir temperature of about 45 °C and an ambient reservoir pressure of about 92 bar at the time of sampling. A complementary water sample was taken at a water production well completed in a respective horizon but located outside the gas storage reservoir. Microbial community analysis by Illumina Sequencing of bacterial and archaeal 16S rRNA genes indicated the presence of phylogenetically diverse microbial communities of high compositional heterogeneity. In three out of four samples originating from the reservoir, the majority of bacterial sequences affiliated with members of the genera Eubacterium, Acetobacterium and Sporobacterium within Clostridiales, known for their fermenting capabilities. In

  12. A step-wise semi-distributed simulation approach to characterize a karst aquifer and to support dam construction in a data-scarce environment

    Science.gov (United States)

    Adinehvand, R.; Raeisi, E.; Hartmann, A.

    2017-11-01

    Karst systems provide significant volumes of drinking water for large parts of the world population. Due to chemical weathering, karst systems are characterized by strong heterogeneity resulting in a complex flow and storage behaviour. Presently available karst modelling strategies account for the karstic heterogeneity but often a lack of data limits their applicability in data-scarce regions. In this study, a step-wise simulation approach with a semi-distributed karst model is proposed to characterize a karst aquifer at a data-scarce region in Southwest Iran and to evaluate the leakage potential related to a future dam construction project at a river that cuts through the aquifer. Observed groundwater level time series were applied to calibrate and validate the model. In order to avoid over-parameterization, the karst aquifer was split into three sections down the hydraulic gradient. At each section, groundwater level observations were used to iteratively calibrate the model from the first to the last section. A spatial split-sample test and sensitivity analysis served to evaluate the prediction performance and the identifiability of the model parameters. Finally, simple scenarios of the river infiltration into the aquifer were applied to evaluate the leakage potential of the aquifer for future dam constructions. The spatial split-sample test showed that the semi-distributed model provided reliable predictions but prediction performance and parameter identifiability decreased from the first towards the last aquifer section, most probably due to increased aquifer complexity and propagation of uncertainty from the up-gradient model section. Using sensitivity analysis, we also show that parameter sensitivities increase significantly if parameter estimation was applied simultaneously to all three aquifer subsections. Using the model to assess the leakage potential indicated that, without further technical measures, the all river flow would be able infiltrate into the

  13. Advances in photonic reservoir computing

    Directory of Open Access Journals (Sweden)

    Van der Sande Guy

    2017-05-01

    Full Text Available We review a novel paradigm that has emerged in analogue neuromorphic optical computing. The goal is to implement a reservoir computer in optics, where information is encoded in the intensity and phase of the optical field. Reservoir computing is a bio-inspired approach especially suited for processing time-dependent information. The reservoir’s complex and high-dimensional transient response to the input signal is capable of universal computation. The reservoir does not need to be trained, which makes it very well suited for optics. As such, much of the promise of photonic reservoirs lies in their minimal hardware requirements, a tremendous advantage over other hardware-intensive neural network models. We review the two main approaches to optical reservoir computing: networks implemented with multiple discrete optical nodes and the continuous system of a single nonlinear device coupled to delayed feedback.

  14. Prediction of the thermohydraulic performance of porous-media reservoirs for compressed-air energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Wiles, L.E.; McCann, R.A.

    1981-09-01

    The numerical modeling capability that has been developed at the Pacific Northwest Laboratory (PNL) for the prediction of the thermohydraulic performance of porous media reservoirs for compressed air energy storage (CAES) is described. The capability of the numerical models was demonstrated by application to a variety of parametric analyses and the support analyses for the CAES porous media field demonstration program. The demonstration site analyses include calculations for the displacement of aquifer water to develop the air storage zone, the potential for water coning, thermal development in the reservoir, and the dehydration of the near-wellbore region. Unique features of the demonstration site reservoir that affect the thermohydraulic performance are identified and contrasted against the predicted performance for conditions that would be considered more typical of a commercial CAES site.

  15. Basement and alluvial aquifers of Malawi: An overview of ...

    African Journals Online (AJOL)

    This paper highlights the quality of groundwater in basement and alluvial aquifers of Malawi through literature assessment. Groundwater in these aquifers serves about 60% of Malawian population. Alluvial aquifers yield high groundwater in excess of 10 L/s and more mineralized than basement aquifers. The values from ...

  16. Hydrology of the Claiborne aquifer and interconnection with the Upper Floridan aquifer in southwest Georgia

    Science.gov (United States)

    Gordon, Debbie W.; Gonthier, Gerard

    2017-04-24

    The U.S. Geological Survey conducted a study, in cooperation with the Georgia Environmental Protection Division, to define the hydrologic properties of the Claiborne aquifer and evaluate its connection with the Upper Floridan aquifer in southwest Georgia. The effort involved collecting and compiling hydrologic data from the aquifer in subarea 4 of southwestern Georgia. Data collected for this study include borehole geophysical logs in 7 wells, and two 72-hour aquifer tests to determine aquifer properties.The top of the Claiborne aquifer extends from an altitude of about 200 feet above the North American Vertical Datum of 1988 (NAVD 88) in Terrell County to 402 feet below NAVD 88 in Decatur County, Georgia. The base of the aquifer extends from an altitude of about 60 feet above NAVD 88 in eastern Sumter County to about 750 feet below NAVD 88 in Decatur County. Aquifer thickness ranges from about 70 feet in eastern Early County to 400 feet in Decatur County.The transmissivity of the Claiborne aquifer, determined from two 72-hour aquifer tests, was estimated to be 1,500 and 700 feet squared per day in Mitchell and Early Counties, respectively. The storage coefficient was estimated to be 0.0006 and 0.0004 for the same sites, respectively. Aquifer test data from Mitchell County indicate a small amount of leakage occurred during the test. Groundwater-flow models suggest that the source of the leakage was the underlying Clayton aquifer, which produced about 2.5 feet of drawdown in response to pumping in the Claiborne aquifer. The vertical hydraulic conductivity of the confining unit between the Claiborne and Clayton aquifers was simulated to be about 0.02 foot per day.Results from the 72-hour aquifer tests run for this study indicated no interconnection between the Claiborne and overlying Upper Floridan aquifers at the two test sites. Additional data are needed to monitor the effects that increased withdrawals from the Claiborne aquifer may have on future water resources.

  17. Seasonal Deep Aquifer Thermal Energy Storage in the Gassum Sandstone Formation

    DEFF Research Database (Denmark)

    Holmslykke, H.D.H.; Kjøller, C.; Fabricius, Ida Lykke

    Seasonal storage of excess heat in hot deep aquifers is considered to optimise the usage of commonly available energy sources. The potential chemical reactions caused by heating the Gassum Sandstone Formation to up to 150°C is investigated by core flooding experiments combined with petrographic...... analysis and geochemical modelling. Synthetic formation water is injected into two sets of Gassum Formation samples at 25°C, 50°C (reservoir temperature), 100°C and 150°C with a velocity of 0.05 PV/hr and 0.1 PV/hr, respectively. A significant increase in the aqueous concentration of silicium and iron...

  18. Gravity observations for hydrocarbon reservoir monitoring

    NARCIS (Netherlands)

    Glegola, M.A.

    2013-01-01

    In this thesis the added value of gravity observations for hydrocarbon reservoir monitoring and characterization is investigated. Reservoir processes and reservoir types most suitable for gravimetric monitoring are identified. Major noise sources affecting time-lapse gravimetry are analyzed. The

  19. Nitrate contamination of groundwater in the catchment of Goczałkowice reservoir

    Science.gov (United States)

    Czekaj, Joanna; Witkowski, Andrzej J.

    2014-05-01

    Goczałkowice dammed reservoir (area - 26 km2 , volume - 100 million m3 at a typical water level) is a very important source of drinking water for Upper Silesian agglomeration. At the catchment of the reservoir there are many potential sources of groundwater pollution (agriculture, bad practices in wastewater management, intensive fish farming). Thus local groundwater contamination, mainly by nitrogen compounds. The paper presents groundwater monitoring system and preliminary results of the research carried on at Goczałkowice reservoir and its catchment in 2010 - 2014 within the project "Integrated system supporting management and protection of dammed reservoir (ZiZoZap)'. The main objective for hydrogeologists in the project is to assess the role of groundwater in total water balance of the reservoir and the influence of groundwater on its water quality. During research temporal variability of groundwater - surface water exchange has been observed. Monitoring Network of groundwater quality consists of 22 observation wells (nested piezometers included) located around the reservoir - 13 piezometers is placed in two transects on northern and southern shore of reservoir. Sampling of groundwater from piezometers was conducted twice - in autumn 2011 and spring 2012. Maximum observed concentrations of nitrate, nitrite and ammonium were 255 mg/L, 0,16 mg/L and 3,48 mg/L, respectively. Surface water in reservoir (8 points) has also been sampled. Concentrations of nitrate in groundwater are higher than in surface water. Nitrate and ammonium concentrations exceeding standards for drinking water were reported in 18% and 50% of monitored piezometers, respectively. High concentration of nitrate (exceeding more than 5 times maximal admissible concentration) have been a significant groundwater contamination problem in the catchment of the reservoir. Periodically decrease of surface water quality is possible. Results of hydrogeological research indicate substantial spatial

  20. Snowmelt Induced Hydrologic Perturbations Drive Dynamic Microbiological and Geochemical Behaviors across a Shallow Riparian Aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Danczak, Robert E.; Yabusaki, Steven B.; Williams, Kenneth H.; Fang, Yilin; Hobson, Chad; Wilkins, Michael J.

    2016-05-11

    Shallow riparian aquifers represent hotspots of biogeochemical activity in the arid western US. While these environments provide extensive ecosystem services, little is known of how natural environmental perturbations influence subsurface microbial communities and associated biogeochemical processes. Over a six-month period we tracked the annual snowmelt-driven incursion of groundwater into the vadose zone of an aquifer adjacent to the Colorado River, leading to increased dissolved oxygen (DO) concentrations in the normally suboxic saturated zone. Strong biogeochemical heterogeneity was measured across the site, with abiotic reactions between DO and sulfide minerals driving rapid DO consumption and mobilization of redox active species in reduced aquifer regions. Conversely, extensive DO increases were detected in less reduced sediments. 16S rRNA gene surveys tracked microbial community composition within the aquifer, revealing strong correlations between increases in putative oxygen-utilizing chemolithoautotrophs and heterotrophs and rising DO concentrations. The gradual return to suboxic aquifer conditions favored increasing abundances of 16S rRNA sequences matching members of the Microgenomates (OP11) and Parcubacteria (OD1) that have been strongly implicated in fermentative processes. Microbial community stability measurements indicated that deeper aquifer locations were relatively less affected by geochemical perturbations, while communities in shallower locations exhibited the greatest change. Reactive transport modeling of the geochemical and microbiological results supported field observations, suggesting that a predictive framework can be applied to develop a greater understanding of such environments. Frontiers in Earth Science Journal Impact & Description - ResearchGate - Impact Rankings ( 2015 and 2016 ). Available from: https://www.researchgate.net/journal/2296-6463_Frontiers_in_Earth_Science [accessed Jul 25, 2016].

  1. Karst Aquifer Recharge: A Case History of over Simplification from the Uley South Basin, South Australia

    Directory of Open Access Journals (Sweden)

    Nara Somaratne

    2015-02-01

    Full Text Available The article “Karst aquifer recharge: Comments on ‘Characteristics of Point Recharge in Karst Aquifers’, by Adrian D. Werner, 2014, Water 6, doi:10.3390/w6123727” provides misrepresentation in some parts of Somaratne [1]. The description of Uley South Quaternary Limestone (QL as unconsolidated or poorly consolidated aeolianite sediments with the presence of well-mixed groundwater in Uley South [2] appears unsubstantiated. Examination of 98 lithological descriptions with corresponding drillers’ logs show only two wells containing bands of unconsolidated sediments. In Uley South basin, about 70% of salinity profiles obtained by electrical conductivity (EC logging from monitoring wells show stratification. The central and north central areas of the basin receive leakage from the Tertiary Sand (TS aquifer thereby influencing QL groundwater characteristics, such as chemistry, age and isotope composition. The presence of conduit pathways is evident in salinity profiles taken away from TS water affected areas. Pumping tests derived aquifer parameters show strong heterogeneity, a typical characteristic of karst aquifers. Uley South QL aquifer recharge is derived from three sources; diffuse recharge, point recharge from sinkholes and continuous leakage of TS water. This limits application of recharge estimation methods, such as the conventional chloride mass balance (CMB as the basic premise of the CMB is violated. The conventional CMB is not suitable for accounting chloride mass balance in groundwater systems displaying extreme range of chloride concentrations and complex mixing [3]. Over simplification of karst aquifer systems to suit application of the conventional CMB or 1-D unsaturated modelling as described in Werner [2], is not suitable use of these recharge estimation methods.

  2. A dynamic flow simulation code benchmark study addressing the highly heterogeneous properties of the Stuttgart formation at the Ketzin pilot site

    Science.gov (United States)

    Kempka, Thomas; Class, Holger; Görke, Uwe-Jens; Norden, Ben; Kolditz, Olaf; Kühn, Michael; Walter, Lena; Wang, Wenqing; Zehner, Björn

    2013-04-01

    CO2 injection at the Ketzin pilot site located in Eastern Germany (Brandenburg) about 25 km west of Berlin is undertaken since June 2008 with a scheduled total amount of about 70,000 t CO2 to be injected into the saline aquifer represented by the Stuttgart Formation at a depth of 630 m to 650 m until the end of August 2013. The Stuttgart Formation is of fluvial origin determined by high-permeablity sandstone channels embedded in a floodplain facies of low permeability indicating a highly heterogeneous distribution of reservoir properties as facies distribution, porosity and permeability relevant for dynamic flow simulations. Following the dynamic modelling activities discussed by Kempka et al. (2010), a revised geological model allowed us to history match CO2 arrival times in the observation wells and reservoir pressure with a good agreement (Martens et al., 2012). Consequently, the validated reservoir model of the Stuttgart Formation at the Ketzin pilot site enabled us to predict the development of reservoir pressure and the CO2 plume migration in the storage formation by dynamic flow simulations. A benchmark study of industrial (ECLIPSE 100 as well as ECLIPSE 300 CO2STORE and GASWAT) and scientific dynamic flow simulations codes (TOUGH2-MP/ECO2N, OpenGeoSys and DuMuX) was initiated to address and compare the simulator capabilities considering a highly complex reservoir model. Hence, our dynamic flow simulations take into account different properties of the geological model such as significant variation of porosity and permeability in the Stuttgart Formation as well as structural geological features implemented in the geological model such as seven major faults located at the top of the Ketzin anticline. Integration of the geological model into reservoir models suitable for the different dynamic flow simulators applied demonstrated that a direct conversion of reservoir model discretization between Finite Volume and Finite Element flow simulators is not feasible

  3. Analysis of aquifer tests conducted in boreholes USW WT-10, UE-25 WT No. 12, and USW SD-7, 1995-96, Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, G.M.

    1997-09-01

    Single-borehole aquifer tests were conducted in three boreholes in the Yucca Mountain area between March 1995 and January 1996 to obtain estimates of borehole specific capacity and aquifer transmissivity. Analysis of aquifer testing in borehole USW SD-7 also resulted in an estimate of reservoir volume. Aquifer-test data were analyzed with the Cooper and Jacob straight-line method, two modified Theis nonequilibrium equation solutions, and a modified reservoir-limit solution. The highest estimates of transmissivity were in borehole USW WT-10, completed in the Topopah Spring Tuff. Mean transmissivity, based on the results of three drawdown tests, was 1,600 meters squared per day. Mean specific capacity in borehole USW WT-10 after 5 hours of pumping was 1,100 meters squared per day, and was estimated to be 740 meters squared per day after 24 hours of pumping. Aquifer testing in borehole UE-25 WT No. 12 appeared to be significantly affected by well losses. A mean transmissivity of 7 meters squared per day was obtained on the basis of analysis of three drawdown tests in borehole UE-25 WT No. 12. Mean specific capacity in borehole UE-25 WT No. 12, after 24 hours of pumping, was 7 meters squared per day. Borehole UE-25 WT No. 12 seemed to be producing water from fractures that could provide only a limited amount of water to the borehole.

  4. Estimated withdrawals from principal aquifers in the United States, 2000

    Science.gov (United States)

    Maupin, Molly A.; Barber, Nancy L.

    2005-01-01

    Fresh ground-water withdrawals from 66 principal aquifers in the United States were estimated for irrigation, public-supply, and self-supplied industrial water uses for the year 2000. Total ground-water withdrawals were 76,500 million gallons per day, or 85,800 thousand acre-feet per year for these three uses. Irrigation used the largest amount of ground water, 56,900 million gallons per day, followed by public supply with 16,000 million gallons per day, and self-supplied industrial with 3,570 million gallons per day. These three water uses represented 92 percent of the fresh groundwater withdrawals for all uses in the United States, the remaining 8 percent included self-supplied domestic, aquaculture, livestock, mining, and thermoelectric power uses. Aquifer withdrawals were categorized by five lithologic groups: unconsolidated and semiconsolidated sand and gravel aquifers, carbonate-rock aquifers, igneous and metamorphic-rock aquifers, sandstone aquifers, and sandstone and carbonate-rock aquifers. Withdrawals from aquifers that were not included in one of the 66 principal aquifers were reported in an “Other” aquifers group. The largest withdrawals in the United States were from unconsolidated and semiconsolidated sand and gravel aquifers, which accounted for 80 percent of total withdrawals from all aquifers. Carbonate-rock aquifers provided 8 percent of the withdrawals, and igneous and metamorphic-rock aquifers, 6 percent. Withdrawals from sandstone aquifers, from sandstone and carbonate-rock aquifers, and from the “Other” aquifers category each constituted about 2 percent of the total withdrawals reported.Fifty-five percent of the total withdrawals for irrigation, public-supply, and self-supplied industrial water uses were provided by the High Plains aquifer, California Central Valley aquifer system, the Mississippi River Valley alluvial aquifer, and the Basin and Range basin-fill aquifers. These aquifers provided most of the withdrawals for irrigation

  5. Analysis of real-time reservoir monitoring : reservoirs, strategies, & modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Mani, Seethambal S.; van Bloemen Waanders, Bart Gustaaf; Cooper, Scott Patrick; Jakaboski, Blake Elaine; Normann, Randy Allen; Jennings, Jim (University of Texas at Austin, Austin, TX); Gilbert, Bob (University of Texas at Austin, Austin, TX); Lake, Larry W. (University of Texas at Austin, Austin, TX); Weiss, Chester Joseph; Lorenz, John Clay; Elbring, Gregory Jay; Wheeler, Mary Fanett (University of Texas at Austin, Austin, TX); Thomas, Sunil G. (University of Texas at Austin, Austin, TX); Rightley, Michael J.; Rodriguez, Adolfo (University of Texas at Austin, Austin, TX); Klie, Hector (University of Texas at Austin, Austin, TX); Banchs, Rafael (University of Texas at Austin, Austin, TX); Nunez, Emilio J. (University of Texas at Austin, Austin, TX); Jablonowski, Chris (University of Texas at Austin, Austin, TX)

    2006-11-01

    The project objective was to detail better ways to assess and exploit intelligent oil and gas field information through improved modeling, sensor technology, and process control to increase ultimate recovery of domestic hydrocarbons. To meet this objective we investigated the use of permanent downhole sensors systems (Smart Wells) whose data is fed real-time into computational reservoir models that are integrated with optimized production control systems. The project utilized a three-pronged approach (1) a value of information analysis to address the economic advantages, (2) reservoir simulation modeling and control optimization to prove the capability, and (3) evaluation of new generation sensor packaging to survive the borehole environment for long periods of time. The Value of Information (VOI) decision tree method was developed and used to assess the economic advantage of using the proposed technology; the VOI demonstrated the increased subsurface resolution through additional sensor data. Our findings show that the VOI studies are a practical means of ascertaining the value associated with a technology, in this case application of sensors to production. The procedure acknowledges the uncertainty in predictions but nevertheless assigns monetary value to the predictions. The best aspect of the procedure is that it builds consensus within interdisciplinary teams The reservoir simulation and modeling aspect of the project was developed to show the capability of exploiting sensor information both for reservoir characterization and to optimize control of the production system. Our findings indicate history matching is improved as more information is added to the objective function, clearly indicating that sensor information can help in reducing the uncertainty associated with reservoir characterization. Additional findings and approaches used are described in detail within the report. The next generation sensors aspect of the project evaluated sensors and packaging

  6. Well testing in gas hydrate reservoirs

    OpenAIRE

    Kome, Melvin Njumbe

    2015-01-01

    Reservoir testing and analysis are fundamental tools in understanding reservoir hydraulics and hence forecasting reservoir responses. The quality of the analysis is very dependent on the conceptual model used in investigating the responses under different flowing conditions. The use of reservoir testing in the characterization and derivation of reservoir parameters is widely established, especially in conventional oil and gas reservoirs. However, with depleting conventional reserves, the ...

  7. Insights from the salinity origins and interconnections of aquifers in a regional scale sedimentary aquifer system (Adour-Garonne district, SW France): Contributions of δ34S and δ18O from dissolved sulfates and the 87Sr/86Sr ratio

    International Nuclear Information System (INIS)

    Brenot, Agnès; Négrel, Philippe; Petelet-Giraud, Emmanuelle; Millot, Romain; Malcuit, Eline

    2015-01-01

    Highlights: • Regional sedimentary aquifer on the Aquitaine Basin (SW France). • Dealing with limited number of groundwater wells available. • Strong control of evaporite dissolution on groundwater dissolved elements. • Guidelines for decision-makers to manage water resources. - Abstract: The multi-layered Eocene aquifer is a regional scale sedimentary aquifer system occupying ∼120,000 km 2 within the Adour-Garonne district (France). Local authorities have recently identified the aquifer as being at risk from extensive irrigation abstractions, threatening the sustainability of this key resource. Because large water abstractions for human activities can significantly influence the natural functioning of such aquifer systems, e.g., with leakage between aquifer layers, which can lead to water quality degradation, the characterization of such large systems constitutes a key point to protect and prevent further deterioration of aquatic ecosystems. This study provides further insight on this large aquifer through a geochemical approach, which addresses the limited number of groundwater wells where sampling is possible. For that purpose, a geochemical analysis combining two isotope systems (δ 34 S SO4 , δ 18 O SO4 and 87 Sr/ 86 Sr) has been applied. The Eocene sedimentary aquifer system (detrital to carbonate deposits) is made up of four aquifer layers, Eocene Infra-Molassic sand, Early Eocene, Middle Eocene and Late Eocene, and has a mineralized area north of the Aquitaine Basin, where groundwater shows strong mineralization and anomalous levels of critical substances (SO 4 , F, etc.), increasing the difficulty of resource exploitation. The extreme heterogeneity of the geochemical composition of the groundwater between the aquifers and within a single aquifer is discussed in terms of the lithological control induced by the lateral variation of facies and interconnections between aquifer layers. Geochemical tools, especially the δ 34 S and δ 18 O from

  8. Fault damage zone volume and initial salinity distribution determine intensity of shallow aquifer salinisation in subsurface storage

    Science.gov (United States)

    Tillner, Elena; Langer, Maria; Kempka, Thomas; Kühn, Michael

    2016-03-01

    Injection of fluids into deep saline aquifers causes a pore pressure increase in the storage formation, and thus displacement of resident brine. Via hydraulically conductive faults, brine may migrate upwards into shallower aquifers and lead to unwanted salinisation of potable groundwater resources. In the present study, we investigated different scenarios for a potential storage site in the Northeast German Basin using a three-dimensional (3-D) regional-scale model that includes four major fault zones. The focus was on assessing the impact of fault length and the effect of a secondary reservoir above the storage formation, as well as model boundary conditions and initial salinity distribution on the potential salinisation of shallow groundwater resources. We employed numerical simulations of brine injection as a representative fluid. Our simulation results demonstrate that the lateral model boundary settings and the effective fault damage zone volume have the greatest influence on pressure build-up and development within the reservoir, and thus intensity and duration of fluid flow through the faults. Higher vertical pressure gradients for short fault segments or a small effective fault damage zone volume result in the highest salinisation potential due to a larger vertical fault height affected by fluid displacement. Consequently, it has a strong impact on the degree of shallow aquifer salinisation, whether a gradient in salinity exists or the saltwater-freshwater interface lies below the fluid displacement depth in the faults. A small effective fault damage zone volume or low fault permeability further extend the duration of fluid flow, which can persist for several tens to hundreds of years, if the reservoir is laterally confined. Laterally open reservoir boundaries, large effective fault damage zone volumes and intermediate reservoirs significantly reduce vertical brine migration and the potential of freshwater salinisation because the origin depth of displaced

  9. Radial Dupuit interface flow to assess the aquifer storage and recovery potential of saltwater aquifers

    OpenAIRE

    Bakker, M.

    2009-01-01

    A new accurate numerical solution is presented for aquifer storage and recovery (ASR) systems in coastal aquifers; flow is approximated as radial Dupuit interface flow. The radial velocities of points on the interface are a function of time, the vertical coordinate, and the dimensionless parameter D (the discharge of the well divided by the product of the hydraulic conductivity, the square of the aquifer thickness, and the dimensionless density difference). The recovery efficiency of an ASR s...

  10. The Importance of Bank Storage in Supplying Baseflow to Rivers Flowing Through Compartmentalized, Alluvial Aquifers

    Science.gov (United States)

    Rhodes, Kimberly A.; Proffitt, Tiffany; Rowley, Taylor; Knappett, Peter S. K.; Montiel, Daniel; Dimova, Natasha; Tebo, Daniel; Miller, Gretchen R.

    2017-12-01

    As water grows scarcer in semiarid and arid regions around the world, new tools are needed to quantify fluxes of water and chemicals between aquifers and rivers. In this study, we quantify the volumetric flux of subsurface water to a 24 km reach of the Brazos River, a lowland river that meanders through the Brazos River Alluvium Aquifer (BRAA), with 8 months of high-frequency differential gaging measurements using fixed gaging stations. Subsurface discharge sources were determined using natural tracers and End-Member Mixing Analysis (EMMA). During a 4 month river stage recession following a high stage event, subsurface discharge decreased from 50 m3/s to 0, releasing a total of 1.0 × 108 m3 of water. Subsurface discharge dried up even as the groundwater table at two locations in the BRAA located 300-500 m from the river remained ˜4 m higher than the river stage. Less than 4% of the water discharged from the subsurface during the prolonged recession period resembled the chemical fingerprint of the alluvial aquifer. Instead, the chemistry of this discharged water closely resembled high stage "event" river water. Together, these findings suggest that the river is well connected to rechargeable bank storage reservoirs but disconnected from the broader alluvial aquifer. The average width of discrete bank storage zones on each side of the river, identified with Electrical Resistivity Tomography (ERT), was approximately 1.5 km. In such highly compartmentalized aquifers, groundwater pumping is unlikely to impact the exchange between the river and the alluvium.

  11. Sediment Characteristics of Tennessee Streams and Reservoirs

    National Research Council Canada - National Science Library

    Trimble, Stanley W; Carey, William P

    1984-01-01

    Suspended-sediment and reservoir sedimentation data have been analyzed to determine sediment yields and transport characteristics of Tennessee streams Data from 31 reservoirs plus suspended-sediment...

  12. A quantitative geologic study of heterogeneity

    International Nuclear Information System (INIS)

    Davis, J.M.; Phillips, F.M.

    1990-01-01

    Spatial variation of hydraulic conductivity has been generally recognized as the dominant medium-dependent control on the transport and dispersion of contaminants in ground water. An empirical study focusing on the relationship between patters of sedimentology and patterns of permeability is being conducted at an outcrop of the Pliocene/Pleistocene Sierra Ladrones formation, central New Mexico. Methods of geostatistics and sedimentary basin analysis are employed to study the problem of aquifer heterogeneity. An air permeameter provides a means of obtaining extensive field measurements of air-flow rates through the sediments. These flow rates are subsequently used to characterize the permeability distribution of the outcrop. Both the geologic information and the air-flow rate data provide the basis for analysis of aquifer heterogeneity. Preliminary geologic mapping indicates that the sediments in the study area are the products of an arid fluvial/interfluvial depositional environment. Probability distribution analysis of the air-flow rate data suggests that the permeability of these sediments is log-normally distributed. The air permeability data are used to estimate variograms and correlation lengths in both the horizontal and vertical directions. At the scale of 10's of centimeters, the horizontal variograms exhibit exponential variogram behaviour . When two distinct lithologies are present, the correlation structure appears to be a nested exponential. Variogram analysis of estimated mean permeability at the scale of meters also shows evidence of a nested correlation structure in the horizontal direction and a periodic correlation structure in the vertical direction. Results of this study suggest that there is a direct connection between observable geologic structure and permeability statistics. (Author) (35 refs., 10 figs., 5 tabs.)

  13. Changes to the Bakomi Reservoir

    Directory of Open Access Journals (Sweden)

    Kubinský Daniel

    2014-08-01

    Full Text Available This article is focused on the analysis and evaluation of the changes of the bottom of the Bakomi reservoir, the total volume of the reservoir, ecosystems, as well as changes in the riparian zone of the Bakomi reservoir (situated in the central Slovakia. Changes of the water component of the reservoir were subject to the deposition by erosion-sedimentation processes, and were identifed on the basis of a comparison of the present relief of the bottom of reservoir obtained from feld measurements (in 2011 with the relief measurements of the bottom obtained from the 1971 historical maps, (i.e. over a period of 40 years. Changes of landscape structures of the riparian zone have been mapped for the time period of 1949–2013; these changes have been identifed with the analysis of ortophotomaps and the feld survey. There has been a signifcant rise of disturbed shores with low herb grassland. Over a period of 40 years, there has been a deposition of 667 m3 of sediments. The results showed that there were no signifcant changes in the local ecosystems of the Bakomi reservoir in comparison to the other reservoirs in the vicinity of Banská Štiavnica.

  14. TRITIUM RESERVOIR STRUCTURAL PERFORMANCE PREDICTION

    Energy Technology Data Exchange (ETDEWEB)

    Lam, P.S.; Morgan, M.J

    2005-11-10

    The burst test is used to assess the material performance of tritium reservoirs in the surveillance program in which reservoirs have been in service for extended periods of time. A materials system model and finite element procedure were developed under a Savannah River Site Plant-Directed Research and Development (PDRD) program to predict the structural response under a full range of loading and aged material conditions of the reservoir. The results show that the predicted burst pressure and volume ductility are in good agreement with the actual burst test results for the unexposed units. The material tensile properties used in the calculations were obtained from a curved tensile specimen harvested from a companion reservoir by Electric Discharge Machining (EDM). In the absence of exposed and aged material tensile data, literature data were used for demonstrating the methodology in terms of the helium-3 concentration in the metal and the depth of penetration in the reservoir sidewall. It can be shown that the volume ductility decreases significantly with the presence of tritium and its decay product, helium-3, in the metal, as was observed in the laboratory-controlled burst tests. The model and analytical procedure provides a predictive tool for reservoir structural integrity under aging conditions. It is recommended that benchmark tests and analysis for aged materials be performed. The methodology can be augmented to predict performance for reservoir with flaws.

  15. Digital data sets that describe aquifer characteristics of the Enid isolated terrace aquifer in northwestern Oklahoma

    Science.gov (United States)

    Becker, C.J.; Runkle, D.L.; Rea, Alan

    1997-01-01

    ARC/INFO export and nonproprietary format files The data sets in this report include digitized aquifer boundaries and maps of hydraulic conductivity, recharge, and ground-water level elevation contours for the Enid isolated terrace aquifer in northwestern Oklahoma. The Enid isolated terrace aquifer covers approximately 82 square miles and supplies water for irrigation, domestic, municipal, and industrial use for the City of Enid and western Garfield County. The Quaternary-age Enid isolated terrace aquifer is composed of terrace deposits that consist of discontinuous layers of clay, sandy clay, sand, and gravel. The aquifer is unconfined and is bounded by the underlying Permian-age Hennessey Group on the east and the Cedar Hills Sandstone Formation of the Permian-age El Reno Group on the west. The Cedar Hills Sandstone Formation fills a channel beneath the thickest section of the Enid isolated terrace aquifer in the midwestern part of the aquifer. All of the data sets were digitized and created from information and maps in a ground-water modeling thesis and report of the Enid isolated terrace aquifer. The maps digitized were published at a scale of 1:62,500. Ground-water flow models are numerical representations that simplify and aggregate natural systems. Models are not unique; different combinations of aquifer characteristics may produce similar results. Therefore, values of hydraulic conductivi