pressure distribution in a layered reservoir with gas-cap and bottom

African Journals Online (AJOL)

2012-07-02

Jul 2, 2012 ... Finally, only fluid ratios is recommended as adequate to reveal which ... pressure derivatives, interlayer cross flow, heterogeneity, reservoir characterization, pressure ... sure derivatives to thoroughly understand movement.

Insights on fluid-rock interaction evolution during deformation from fracture network geochemistry at reservoir-scale

Science.gov (United States)

Beaudoin, Nicolas; Koehn, Daniel; Lacombe, Olivier; Bellahsen, Nicolas; Emmanuel, Laurent

2015-04-01

Fluid migration and fluid-rock interactions during deformation is a challenging problematic to picture. Numerous interplays, as between porosity-permeability creation and clogging, or evolution of the mechanical properties of rock, are key features when it comes to monitor reservoir evolution, or to better understand seismic cycle n the shallow crust. These phenomenoms are especially important in foreland basins, where various fluids can invade strata and efficiently react with limestones, altering their physical properties. Stable isotopes (O, C, Sr) measurements and fluid inclusion microthermometry of faults cement and veins cement lead to efficient reconstruction of the origin, temperature and migration pathways for fluids (i.e. fluid system) that precipitated during joints opening or faults activation. Such a toolbox can be used on a diffuse fracture network that testifies the local and/or regional deformation history experienced by the rock at reservoir-scale. This contribution underlines the advantages and limits of geochemical studies of diffuse fracture network at reservoir-scale by presenting results of fluid system reconstruction during deformation in folded structures from various thrust-belts, tectonic context and deformation history. We compare reconstructions of fluid-rock interaction evolution during post-deposition, post-burial growth of basement-involved folds in the Sevier-Laramide American Rocky Mountains foreland, a reconstruction of fluid-rock interaction evolution during syn-depostion shallow detachment folding in the Southern Pyrenean foreland, and a preliminary reconstruction of fluid-rock interactions in a post-deposition, post-burial development of a detachment fold in the Appenines. Beyond regional specification for the nature of fluids, a common behavior appears during deformation as in every fold, curvature-related joints (related either to folding or to foreland flexure) connected vertically the pre-existing stratified fluid system

Fluid typing and tortuosity analysis with NMR-DE techniques in volcaniclastic reservoirs, Patagonia/Argentina

Energy Technology Data Exchange (ETDEWEB)

Bustos, Ulises Daniel [Schlumberger Argentina S.A., Buenos Aires (Argentina); Breda, Eduardo Walter [Repsol YPF Comodoro Rivadavia, Chubut (Argentina)

2004-07-01

Alternative hydrocarbon-detection techniques are used to differentiate water from hydrocarbon where resistivity-based methods are difficult to apply, such as freshwater reservoirs and complex lithologies. One of these areas is represented by the complex volcaniclastic freshwater reservoirs in the Golfo San Jorge basin, Patagonia Argentina, where water and oil have often identical response on conventional logs. Some advances in hydrocarbon identification based on nuclear magnetic resonance (NMR) techniques were achieved in long T1 environments (very light oils, gas) in the Golfo San Jorge basin by previous NMR fluid typing methods. However, since medium to heavy oils are commonly present in these intervals, hydrocarbon detection by such techniques cannot be properly achieved. In addition, restricted diffusion phenomena recognized in these intervals, constitute further complications in fluid typing since its presence have similar response than native oil. To address this problem, a fluid characterization method using NMR Diffusion-Editing techniques and processing/interpretation with D-T2 maps in a suite of NMR measurements was applied. The technique allowed the detection and evaluation of restricted diffusion in these reservoirs, enabling better hydrocarbon characterization in a broad viscosity range (from light to heavy). The method also improved the petrophysical evaluation because restricted diffusion is related to tortuosity in the reservoir. Since the application of this innovative reservoir evaluation method, fluid prognosis vs well completion results was increased from around 68% to around 88% in Golfo San Jorge basin. Moreover, in some of these areas rates above 95% were recently achieved in 2004. (author)

The movements of pikeperch in a shallow reservoir

DEFF Research Database (Denmark)

Jepsen, Niels; Koed, Anders; Økland, F.

1999-01-01

The movements of 12 female (62-74 cm) and eight male pikeperch (55-64 cm) radiotagged in early March 1997 in the shallow and turbid Bygholm Reservoir, peaked during the summer, but all fish were also active during the winter. Females moved more than males and their activity was correlated with wa...... in areas with many submerged trees and shrubs. Males tended to use the same spawning site the next year. Diel activity pattern varied seasonally but activity was highest from 1800 to 2400 hours. (C) 1999 The Fisheries Society of the British Isles....

The model coupling fluid flow in reservoir with flow in horizontal wellbore

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiangping; Jiang, Zhixiang [RIPED-TEXACO Horizontal Well Technology Laboratory (United States)

1998-12-31

Three-dimensional pressure distributions of oil flow in a reservoir with horizontal well were derived, and a new formula to calculate pressure drop along the horizontal wellbore was developed based on the principle of conservation of matter and momentum. The formula considers the effect of influx into the horizontal wellbore from the reservoir on pressure drop in the wellbore. A mathematical model to couple fluid flow in the reservoir with flow in the horizontal wellbore is presented. Model results and experimental data showed good correspondence. Results showed the influence of pressure drop on well performance. 13 refs., 2 tabs., 7 figs.

Water coning in porous media reservoirs for compressed air energy storage

Energy Technology Data Exchange (ETDEWEB)

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

1981-06-01

The general purpose of this work is to define the hydrodynamic and thermodynamic response of a CAES porous media reservoir subjected to simulated air mass cycling. This research will assist in providing design guidelines for the efficient and stable operation of the air storage reservoir. This report presents the analysis and results for the two-phase (air-water), two-dimensional, numerical modeling of CAES porous media reservoirs. The effects of capillary pressure and relative permeability were included. The fluids were considered to be immisicible; there was no phase change; and the system was isothermal. The specific purpose of this analysis was to evaluate the reservoir parameters that were believed to be important to water coning. This phenomenon may occur in reservoirs in which water underlies the air storage zone. It involves the possible intrusion of water into the wellbore or near-wellbore region. The water movement is in response to pressure gradients created during a reservoir discharge cycle. Potential adverse effects due to this water movement are associated with the pressure response of the reservoir and the geochemical stability of the near-wellbore region. The results obtained for the simulated operation of a CAES reservoir suggest that water coning should not be a severe problem, due to the slow response of the water to the pressure gradients and the relatively short duration in which those gradients exist. However, water coning will depend on site-specific conditions, particularly the fluid distributions following bubble development, and, therefore, a water coning analysis should be included as part of site evaluation.

Method for monitoring fluid movement behind casing in oil and gas wells

International Nuclear Information System (INIS)

Fertl, W.H.

1981-01-01

A new method was developed for locating fluid movement between the casing and the earth formations in a cased earth borehole. It comprises traversing a cased earth borehole with a gamma ray detector, thereby creating a base log; injecting a fluid containing a salt of potassium, thorium or uranium into the formation; and creating a second log indicative of the movement of the injected fluid. (D.N.)

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

Improved reservoir characterization from waterflood tracer movement, Northwest Fault Block, Prudhoe Bay, Alaska

International Nuclear Information System (INIS)

Nitzberg, K.E.; Broman, W.H.

1992-01-01

This paper reports that simulation models of the Prudhoe Bay Northwest Fault Block (NWFB) waterflood project, with core-plug-derived permeabilities, predicted that injected water would slump because of gravity segregation. Detailed analysis of surveillance logs and production data for one pattern identified tritium tracer breakthrough in surrounding producers without significant slumping. To duplicate the nearly horizontal movement of injected water, a k V /k H ratio that is an order of magnitude lower than previously modeled is required. This improved reservoir characterization led to revision of the reservoir management strategy for the NWFB

Effects of mechanical layering on hydrofracture emplacement and fluid transport in reservoirs

Directory of Open Access Journals (Sweden)

Sonja Leonie Philipp

2013-12-01

Full Text Available Fractures generated by internal fluid pressure, for example, dykes, mineral veins, many joints and man-made hydraulic fractures, are referred to as hydrofractures. Together with shear fractures, they contribute significantly to the permeability of fluid reservoirs such as those of petroleum, geothermal water, and groundwater. Analytical and numerical models show that – in homogeneous host rocks – any significant overpressure in hydrofractures theoretically generates very high crack tip tensile stresses. Consequently, overpressured hydrofractures should propagate and help to form interconnected fracture systems that would then contribute to the permeability of fluid reservoirs. Field observations, however, show that in heterogeneous and anisotropic, e.g., layered, rocks many hydrofractures become arrested or offset at layer contacts and do not form vertically interconnected networks. The most important factors that contribute to hydrofracture arrest are discontinuities (including contacts, stiffness changes between layers, and stress barriers, where the local stress field is unfavourable to hydrofracture propagation. A necessary condition for a hydrofracture to propagate to the surface is that the stress field along its potential path is everywhere favourable to extension-fracture formation so that the probability of hydrofracture arrest is minimised. Mechanical layering and the resulting heterogeneous stress field largely control whether evolving hydrofractures become confined to single layers (strata¬bound frac¬tures or not (non-stratabound fractures and, there¬fore, if a vertically intercon¬nec¬ted fracture system forms. Non-stratabound hydrofractures may propagate through many layers and generate interconnected fracture systems. Such systems commonly reach the percolation threshold and largely control the overall permeability of the fluid reservoirs within which they develop.

Movements of adult Atlantic salmon through a reservoir above a hydroelectric dam: Loch Faskally

International Nuclear Information System (INIS)

Gowans, A.R.D.; Priede, I.G.

1999-01-01

Movements of adult Atlantic salmon were determined as they migrated through Loch Faskally, a 4-km long hydroelectric reservoir in North-east Scotland. The horizontal and vertical movements of four salmon were monitored for periods of 4-7 days using depth-sensing acoustic transmitters in June-July 1995. Each fish began sustained directed upstream movements within 5.5 h after release at swimming speeds of 0.15-0.40 bl s -1 . Three fish reached the head of the loch after 7.25-17 h, but then returned downstream. The four fish remained in the upper half of the loch for 15-51 days, making localized movements. Mean depths of fish were 3.7-4.0 m (max 20.7 m). Two fish were recorded at significantly shallower depths at night during the day. Departure from the loch coincided with periods of high water flow into the reservoir. In May-July 1996, 17 radio-tagged salmon entered Loch Faskally and reached the head of the loch in 3 h-5.8 days (mean 39 h). The durations of stay in the loch varied from 3 h 50 min to 67.4 days (mean 10.9 days). Only two radio-tagged salmon left the loch under conditions of high water flow into the loch. (author)

Fluid Assisted Compaction and Deformation of Reservoir Lithologies; FINAL

International Nuclear Information System (INIS)

Kronenberg, A.K.; Chester, F.M.; Chester, J.S.; Hajash, A.; He, W.; Karner, S.; Lenz, S.

2002-01-01

The compaction and diagenesis of sandstones that form reservoirs to hydrocarbons depend on mechanical compaction processes, fluid flow at local and regional scales, and chemical processes of dissolution, precipitation and diffusional solution transport. The compaction and distortional deformation of quartz aggregates exposed to reactive aqueous fluids have been investigated experimentally at varying critical and subcritical stress states and time scales. Pore fluid compositions and reaction rates during deformation have been measured and compared with creep rates. Relative contributions of mechanical and chemical processes to deformation and pore structure evolution have been evaluated using acoustic emission (AE) measurements and scanning electron microscope (SEM) observations. At the subcritical conditions investigated, creep rates and acoustic emission rates fit transient logarithmic creep laws. Based on AE and SEM observations, we conclude that intragranular cracking and grain rearrangement are the dominant strain mechanisms. Specimens show little evidence of stress-enhanced solution transfer. At long times under wet conditions, the dominant strain mechanism gradually shifts from critical cracking at grain contacts with high stress concentrations to fluid-assisted sub-critical cracking

Acoustic dew point and bubble point detector for gas condensates and reservoir fluids

Energy Technology Data Exchange (ETDEWEB)

Sivaraman, A.; Hu, Y.; Thomas, F. B.; Bennion, D. B.; Jamaluddin, A. K. M. [Hycal Energy Research Labs. Ltd., Calgary, AB (Canada)

1997-08-01

Detailed knowledge of bubblepoint and dewpoint pressures at reservoir temperature are crucial for natural gas processing, transportation, metering and utilization. This paper introduces a new acoustic dewpoint and bubblepoint detector that can be applied to a broad range of phase transitions, including very lean gas systems and opaque heavy oils. The system uses two acoustic transducers, one to stimulate and the other to detect normal mode vibrations of reservoir fluids in a small cylindrical resonator. The acoustic spectra are recorded at close intervals throughout the phase envelope, along with temperature, pressure and volume measurements, and the data is processed to obtain the specific condition of phase transition. Results of two systems, a binary mixture and live reservoir fluid, are presented. The detector system is claimed to be capable of operation in an isothermal mode with variable volume, and in a constant volume mode with variable temperatures. Interpretation of results is free of operator subjectivity; they show excellent agreement with results obtained by visual methods and equations of state calculations. 4 refs., 2 tabs., 4 figs.

Development of a Cerebrospinal Fluid Lateral Reservoir Model in Rhesus Monkeys (Macaca mulatta)

OpenAIRE

Lester McCully, Cynthia M; Bacher, John; MacAllister, Rhonda P; Steffen-Smith, Emilie A; Saleem, Kadharbatcha; Thomas, Marvin L; Cruz, Rafael; Warren, Katherine E

2015-01-01

Rapid, serial, and humane collection of cerebrospinal fluid (CSF) in nonhuman primates (NHP) is an essential element of numerous research studies and is currently accomplished via two different models. The CSF reservoir model (FR) combines a catheter in the 4th ventricle with a flexible silastic reservoir to permit circulating CSF flow. The CSF lateral port model (LP) consists of a lateral ventricular catheter and an IV port that provides static access to CSF and volume restrictions on sample...

Interaction between Proppant Packing, Reservoir Depletion, and Fluid Flow in Pore Space

Science.gov (United States)

Fan, M.; McClure, J. E.; Han, Y.; Chen, C.

2016-12-01

In the oil and gas industry, the performance of proppant pack in hydraulically created fractures has a significant influence on fracture conductivity. A better understanding of proppant transport and deposition pattern in a hydraulic fracture is vital for effective and economical production within oil and gas reservoirs. In this research, a numerical modeling approach, combining Particle Flow Code (PFC) and GPU-enhanced lattice Boltzmann simulator (GELBS), is adopted to advance the understanding of the interaction between proppant particle packing, depletion of reservoir formation, and transport of reservoir flow through the pore space. In this numerical work flow, PFC is used to simulate effective stress increase and proppant particle movement and rearrangement under increasing mechanical loading. The pore structure of the proppant pack evolves subsequently and the geometrical data are output for lattice Boltzmann (LB) simulation of proppant pack permeability. Three different proppant packs with fixed particle concentration and 12/18, 16/30, and 20/40 mesh sizes are generated. These proppant packs are compressed with specified loading stress and their subsequent geometries are used for fluid flow simulations. The simulation results are in good agreement with experimental observations, e.g., the conductivity of proppant packs decreases with increasing effective stress. Three proppant packs with the same average diameter were generated using different coefficients of variation (COVs) for the proppant diameter (namely cov5%, cov20%, and cov30%). By using the coupled PFC-LBM work flow, the proppant pack permeability as functions of effective stress and porosity is investigated. The results show that the proppant pack with a higher proppant diameter COV has lower permeability and porosity under the same effective stress, because smaller particles fill in the pore space between bigger particles. The relationship between porosity and permeability is also consistent with

On Fluid and Thermal Dynamics in a Heterogeneous CO2 Plume Geothermal Reservoir

Directory of Open Access Journals (Sweden)

Tianfu Xu

2017-01-01

Full Text Available CO2 is now considered as a novel heat transmission fluid to extract geothermal energy. It can achieve both the energy exploitation and CO2 geological sequestration. The migration pathway and the process of fluid flow within the reservoirs affect significantly a CO2 plume geothermal (CPG system. In this study, we built three-dimensional wellbore-reservoir coupled models using geological and geothermal conditions of Qingshankou Formation in Songliao Basin, China. The performance of the CPG system is evaluated in terms of the temperature, CO2 plume distribution, flow rate of production fluid, heat extraction rate, and storage of CO2. For obtaining a deeper understanding of CO2-geothermal system under realistic conditions, heterogeneity of reservoir’s hydrological properties (in terms of permeability and porosity is taken into account. Due to the fortissimo mobility of CO2, as long as a highly permeable zone exists between the two wells, it is more likely to flow through the highly permeable zone to reach the production well, even though the flow path is longer. The preferential flow shortens circulation time and reduces heat-exchange area, probably leading to early thermal breakthrough, which makes the production fluid temperature decrease rapidly. The analyses of flow dynamics of CO2-water fluid and heat may be useful for future design of a CO2-based geothermal development system.

Can introduction of hydraulic fracturing fluids induce biogenic methanogenesis in the shale reservoirs?

Science.gov (United States)

Sharma, S.; Wilson, T.; Wrighton, K. C.; Borton, M.; O'Banion, B.

2017-12-01

The hydraulic fracturing fluids (HFF) injected into the shale formation are composed primarily of water, proppant and some chemical additives ( 0.5- 2% by volume). The additives contain a lot of organic and inorganic compounds like ammonium sulfate, guar gum, boric acid, hydrochloric acid, citric acid, potassium carbonate, glutaraldehyde, ethylene glycols which serve as friction reducers, gelling agents, crosslinkers, biocides, corrosion/scale inhibitors, etc. The water and additives introduced into the formation ensue a variety of microbiogechmical reactions in the reservoir. For this study produced, water and gas samples were collected from several old and new Marcellus wells in SE Pennsylvania and NE West Virginia to better understand these microbe-water-rock interactions. The carbon isotopic composition of dissolved inorganic carbon (δ13CDIC) in the produced fluids and CO2 in produced gas (δ13CCO2) are highly enriched with values > +10‰ and +14 ‰ V-PDB respectively. The injected hydraulic fracturing fluid had low δ13CDIC values of detectable carbon in them. The drilling mud and carbonate veins had δ13C values of -1.8 and < 2.0 ‰ V-PDB respectively. Therefore, the high δ13CDIC signatures in produced water are possibly due to the microbial utilization of lighter carbon (12C) by microbes or methanogenic bacteria in the reservoir. It is possible that introduction of C containing nutrients like guar, methanol, methylamines, etc. stimulates certain methanogen species in the reservoir to produce biogenic methane. Genomic analysis reveals that methanogen species like Methanohalophilus or Methanolobus could be the possible sources of biogenic methane in these shale reservoirs. The evidence of microbial methanogenesis raises the possibility of enhanced gas recovery from these shales using biological amendments.

The application of SEM in analyzing the damage to the petroleum reservoirs caused by drilling fluids

International Nuclear Information System (INIS)

Abdul Razak Ismail

1996-01-01

An experimental study has been conducted to analyze the damage to the potential oil and gas reservoirs due to the invasion of drilling fluid during drilling operation. Two types of rock samples representing low and high permeability were used to stimulate the petroleum reservoirs. Sea water based drilling fluids were used in this study. Detail observations to the rock samples were analyzed using scanning electron microscope (SEM). The results of both permeability restoration and SEM observation showed that severe permeability impairments were obtained for high permeability rock. These results indicate that the relative size of the barite particles and the pore size distribution and characteristics of the formation play an important role in determining the damage caused by the drilling fluids

Liquid petroleum gas fracturing fluids for unconventional gas reservoirs

Energy Technology Data Exchange (ETDEWEB)

Taylor, R.S.; Funkhouser, G.P.; Watkins, H.; Attaway, D. [Halliburton Energy Services, Calgary, AB (Canada); Lestz, R.S.; Wilson, L. [Chevron Canada Resources, Calgary, AB (Canada)

2006-07-01

This paper presented details of a gelled liquid petroleum gas (LPG) based fracturing fluid designed to address phase trapping concerns by replacing water with a mixture of LPG and a volatile hydrocarbon fluid. The system eliminates the need for water, which is a growing concern in terms of its availability. In the application process, up to 100 per cent gelled LPG is used for the pad and flush. Sand slurry stages are comprised of a mixture of up to 90 per cent LPG, with the balance of the volume being a volatile hydrocarbon base fluid. The fluid system is not adversely affected by shear, which ensures that acceptable fluid rheology is delivered. Viscosity can be adjusted during the treatment because the surfactant gellant and crosslinker are run in a 1:1 ratio and have good tolerance to concentration variations. The application ratio also allows for fast and accurate visual checks on amounts pumped during the treatment. A portion of the LPG in the fluid can be reproduced as a gas, while the remaining LPG is dissolved in the hydrocarbon fluid and is produced back as a miscible mixture through the use of a methane drive mechanism. Clean-up is facilitated by eliminating water and having LPG as up to 80-90 per cent of the total fluid system, even when wells have low permeability and reservoir pressure. However, LPG and optimized base oils are more expensive than other fluids. It was concluded that the higher costs of the system can be recovered through eliminating the need for swabbing, coiled tubing and nitrogen. Higher final stabilized productions rates may also offset initial costs. 7 refs., 2 tabs., 2 figs.

Bones and oil reservoirs : bioengineers use oilpatch technology to study fluid flow in bones

Energy Technology Data Exchange (ETDEWEB)

Marsters, S.

2003-06-01

The fact that porosity and the presence of channels are qualities that are common to oil reservoirs and bones, led to the use of reservoir modelling technology in investigating bone disorders and to the discovery of dramatic changes in the structure and blood supply of osteoarthritic bones that lie under degenerating cartilage. CMG (Computer Modelling Group) Ltd., developers of reservoir simulation software claim that their software packages can help with the modelling of cellular responses to strains and deformations that occur as fluid flows through bone after a traumatic event such as a tear in the anterior cruciate ligament, a common sports-related injury. Researchers at the University of Calgary expect that by looking at the changes in blood and fluid flow within the bone, they can attain a better understanding of the chain of events that leads to osteoarthritis. Better understanding of the progression of the disease could eventually lead to more precise administration of drugs to deal with osteoarthritic pain, and even to the prevention of painful arthritic joints.

Computational Fluid Dynamics and Room Air Movement

DEFF Research Database (Denmark)

Nielsen, Peter Vilhelm

2004-01-01

on the mass fraction transport equation. The importance of ?false? or numerical diffusion is also addressed in connection with the simple description of a supply opening. The different aspects of boundary conditions in the indoor environment as e.g. the simulation of Air Terminal Devices and the simulation......Nielsen, P.V. Computational Fluid Dynamics and Room Air Movement. Indoor Air, International Journal of Indoor Environment and Health, Vol. 14, Supplement 7, pp. 134-143, 2004. ABSTRACT Computational Fluid Dynamics (CFD) and new developments of CFD in the indoor environment as well as quality...... considerations are important elements in the study of energy consumption, thermal comfort and indoor air quality in buildings. The paper discusses the quality level of Computational Fluid Dynamics and the involved schemes (first, second and third order schemes) by the use of the Smith and Hutton problem...

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.

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

1997-12-31

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.

Modeling Study of High Pressure and High Temperature Reservoir Fluids

DEFF Research Database (Denmark)

Varzandeh, Farhad

properties like saturation pressures, densities at reservoir temperature and Stock TankviOil (STO) densities, while keeping the n-alkane limit of the correlations unchanged. Apart from applying this general approach to PC-SAFT, we have also shown that the approach can be applied to classical cubic models...... approach to characterizing reservoir fluids for any EoS. The approach consists in developing correlations of model parameters first with a database for well-defined components and then adjusting the correlations with a large PVT database. The adjustment is made to minimize the deviation in key PVT...... method to SRK and PR improved the saturation pressure calculation in comparisonto the original characterization method for SRK and PR. Using volume translationtogether with the new characterization approach for SRK and PR gives comparable results for density and STO density to that of original...

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

Modelling and simulation of compressible fluid flow in oil reservoir: a case study of the Jubilee Field, Tano Basin (Ghana)

International Nuclear Information System (INIS)

Gawusu, S.

2015-07-01

Oil extraction represents an important investment and the control of a rational exploitation of a field means mastering various scientific techniques including the understanding of the dynamics of fluids in place. This thesis presents a theoretical investigation of the dynamic behaviour of an oil reservoir during its exploitation. The study investigated the dynamics of fluid flow patterns in a homogeneous oil reservoir using the Radial Diffusivity Equation (RDE) as well as two phase oil-water flow equations. The RDE model was solved analytically and numerically for pressure using the Constant Terminal Rate Solution (CTRS) and the fully implicit Finite Difference Method (FDM) respectively. The mathematical derivations of the models and their solution procedures were presented to allow for easy utilization of the techniques for reservoir and engineering applications. The study predicted that the initial oil reservoir pressure will be able to do the extraction for a very long time before any other recovery method will be used to aid in the extraction process depending on the rate of production. Reservoir simulation describing a one dimensional radial flow of a compressible fluid in porous media may be adequately performed using ordinary laptop computers as revealed by the study. For the simulation of MATLAB, the case of the Jubilee Fields, Tano Basin was studied, an algorithm was developed for the simulation of pressure in the reservoir. It ensues from the analysis of the plots of pressure vrs time and space that the Pressure Transient Analysis (PTA) was duly followed. The approximate solutions of the analytical and numerical solutions to the Radial Diffusivity Equation (RDE) were in excellent agreement, thus the reservoir simulation model developed can be used to describe typical pressure-time relationships that are used in conventional Pressure Transient Analysis (PTA). The study was extended to two phase oil-water flow in reservoirs. The flow of fluids in multi

Development of gas and gas condensate reservoirs

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-12-01

In the study of gas reservoir development, the first year topics are restricted on reservoir characterization. There are two types of reservoir characterization. One is the reservoir formation characterization and the other is the reservoir fluid characterization. For the reservoir formation characterization, calculation of conditional simulation was compared with that of unconditional simulation. The results of conditional simulation has higher confidence level than the unconditional simulation because conditional simulation considers the sample location as well as distance correlation. In the reservoir fluid characterization, phase behavior calculations revealed that the component grouping is more important than the increase of number of components. From the liquid volume fraction with pressure drop, the phase behavior of reservoir fluid can be estimated. The calculation results of fluid recombination, constant composition expansion, and constant volume depletion are matched very well with the experimental data. In swelling test of the reservoir fluid with lean gas, the accuracy of dew point pressure forecast depends on the component characterization. (author). 28 figs., 10 tabs.

Understanding CO2 Plume Behavior and Basin-Scale Pressure Changes during Sequestration Projects through the use of Reservoir Fluid Modeling

Science.gov (United States)

Leetaru, H.E.; Frailey, S.M.; Damico, J.; Mehnert, E.; Birkholzer, J.; Zhou, Q.; Jordan, P.D.

2009-01-01

Large scale geologic sequestration tests are in the planning stages around the world. The liability and safety issues of the migration of CO2 away from the primary injection site and/or reservoir are of significant concerns for these sequestration tests. Reservoir models for simulating single or multi-phase fluid flow are used to understand the migration of CO2 in the subsurface. These models can also help evaluate concerns related to brine migration and basin-scale pressure increases that occur due to the injection of additional fluid volumes into the subsurface. The current paper presents different modeling examples addressing these issues, ranging from simple geometric models to more complex reservoir fluid models with single-site and basin-scale applications. Simple geometric models assuming a homogeneous geologic reservoir and piston-like displacement have been used for understanding pressure changes and fluid migration around each CO2 storage site. These geometric models are useful only as broad approximations because they do not account for the variation in porosity, permeability, asymmetry of the reservoir, and dip of the beds. In addition, these simple models are not capable of predicting the interference between different injection sites within the same reservoir. A more realistic model of CO2 plume behavior can be produced using reservoir fluid models. Reservoir simulation of natural gas storage reservoirs in the Illinois Basin Cambrian-age Mt. Simon Sandstone suggest that reservoir heterogeneity will be an important factor for evaluating storage capacity. The Mt. Simon Sandstone is a thick sandstone that underlies many significant coal fired power plants (emitting at least 1 million tonnes per year) in the midwestern United States including the states of Illinois, Indiana, Kentucky, Michigan, and Ohio. The initial commercial sequestration sites are expected to inject 1 to 2 million tonnes of CO2 per year. Depending on the geologic structure and

Characterization of microbial community and the alkylscccinate synthase genes in petroleum reservoir fluids of China

Energy Technology Data Exchange (ETDEWEB)

Zhou, Lei; Mu, Bo-Zhong [University of Science and Technology (China)], email: bzmu@ecust.edu.cn; Gu, Ji-Dong [The University of Hong Kong (China)], email: jdgu@hkucc.hku.hk

2011-07-01

Petroleum reservoirs represent a special ecosystem consisting of specific temperature, pressure, salt concentration, oil, gas, water, microorganisms and, enzymes among others. This paper presents the characterization of microbial community and the alkyl succinate synthase genes in petroleum reservoir fluids in China. A few samples were analyzed and the physical and chemical characteristics are given in a tabular form. A flow chart shows the methods and procedures for microbial activities. Six petroleum reservoirs were studied using an archaeal 16S rRNA gene-based approach to establish the presence of archaea and the results are given. The correlation of archaeal and bacterial communities with reservoir conditions and diversity of the arachaeal community in water-flooding petroleum reservoirs at different temperatures is also shown. From the study, it can be summarized that, among methane producers, CO2-reducing methanogens are mostly found in oil reservoir ecosystems and as more assA sequences are revealed, more comprehensive molecular probes can be designed to track the activity of anaerobic alkane-degrading organisms in the environment.

An Analytical Model for Assessing Stability of Pre-Existing Faults in Caprock Caused by Fluid Injection and Extraction in a Reservoir

Science.gov (United States)

Wang, Lei; Bai, Bing; Li, Xiaochun; Liu, Mingze; Wu, Haiqing; Hu, Shaobin

2016-07-01

Induced seismicity and fault reactivation associated with fluid injection and depletion were reported in hydrocarbon, geothermal, and waste fluid injection fields worldwide. Here, we establish an analytical model to assess fault reactivation surrounding a reservoir during fluid injection and extraction that considers the stress concentrations at the fault tips and the effects of fault length. In this model, induced stress analysis in a full-space under the plane strain condition is implemented based on Eshelby's theory of inclusions in terms of a homogeneous, isotropic, and poroelastic medium. The stress intensity factor concept in linear elastic fracture mechanics is adopted as an instability criterion for pre-existing faults in surrounding rocks. To characterize the fault reactivation caused by fluid injection and extraction, we define a new index, the "fault reactivation factor" η, which can be interpreted as an index of fault stability in response to fluid pressure changes per unit within a reservoir resulting from injection or extraction. The critical fluid pressure change within a reservoir is also determined by the superposition principle using the in situ stress surrounding a fault. Our parameter sensitivity analyses show that the fault reactivation tendency is strongly sensitive to fault location, fault length, fault dip angle, and Poisson's ratio of the surrounding rock. Our case study demonstrates that the proposed model focuses on the mechanical behavior of the whole fault, unlike the conventional methodologies. The proposed method can be applied to engineering cases related to injection and depletion within a reservoir owing to its efficient computational codes implementation.

Mathematical simulation of oil reservoir properties

International Nuclear Information System (INIS)

Ramirez, A.; Romero, A.; Chavez, F.; Carrillo, F.; Lopez, S.

2008-01-01

The study and computational representation of porous media properties are very important for many industries where problems of fluid flow, percolation phenomena and liquid movement and stagnation are involved, for example, in building constructions, ore processing, chemical industries, mining, corrosion sciences, etc. Nevertheless, these kinds of processes present a noneasy behavior to be predicted and mathematical models must include statistical analysis, fractal and/or stochastic procedures to do it. This work shows the characterization of sandstone berea core samples which can be found as a porous media (PM) in natural oil reservoirs, rock formations, etc. and the development of a mathematical algorithm for simulating the anisotropic characteristics of a PM based on a stochastic distribution of some of their most important properties like porosity, permeability, pressure and saturation. Finally a stochastic process is used again to simulated the topography of an oil reservoir

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.

About the movement of an ideal fluid contained in an elastic container

International Nuclear Information System (INIS)

Fraguela Collar, A.

1990-11-01

In this paper one considers the linearized problem about the determination of the movement of an ideal heavy fluid contained in an unbounded container with elastic walls. As initial data one knows the movement of the bottom and of the free surface of the fluid and also the strength of certain perturbation enough to take the bottom out of its rest state. One important point to be considered regards the influence of the bottom's geometry on the propagation of superficial waves. This problem has been already studied in other works without considering the elastic properties of the bottom and considering a cylindrical container with bounded section. (author). 8 refs

Mercury-free PVT apparatus for thermophysical property analyses of hydrocarbon reservoir fluids. Final report, August 16, 1990--July 31, 1992

Energy Technology Data Exchange (ETDEWEB)

Lansangan, R.M.; Lievois, J.S.

1992-08-31

Typical reservoir fluid analyses of complex, multicomponent hydrocarbon mixtures include the volumetric properties, isothermal compressibility, thermal expansivity, equilibrium ratios, saturation pressure, viscosities, etc. These parameters are collectively referred to as PVT properties, an acronym for the primary state variables; pressure, volume, and temperature. The reservoir engineer incorporates this information together with the porous media description in performing material balance calculations. These calculations lead to the determination (estimation) of the initial hydrocarbon in-place, the future reservoir performance, the optimal production scheme, and the ultimate hydrocarbon recovery. About four years ago, Ruska Instrument Corporation embarked on a project to develop an apparatus designed to measure PVT properties that operates free of mercury. The result of this endeavor is the 2370 Hg-Free PVT system which has been in the market for the last three years. The 2370 has evolved from the prototype unit to its present configuration which is described briefly in this report. The 2370 system, although developed as a system-engineered apparatus based on existing technology, has not been exempt from this burden-of-proof Namely, the performance of the apparatus under routine test conditions with real reservoir fluids. This report summarizes the results of the performance and applications testing of the 2370 Hg-Free PVT system. Density measurements were conducted on a pure fluid. The results were compared against literature values and the prediction of an equation of state. Routine reservoir fluid analyses were conducted with a black oil and a retrograde condensate gas mixtures. Limited comparison of the results were performed based on the same tests performed on a conventional mercury-based PVT apparatus. The results of these tests are included in this report.

Damage evaluation on oil-based drill-in fluids for ultra-deep fractured tight sandstone gas reservoirs

Directory of Open Access Journals (Sweden)

Jinzhi Zhu

2017-07-01

Full Text Available In order to explore the damage mechanisms and improve the method to evaluate and optimize the performance of formation damage control of oil-based drill-in fluids, this paper took an ultra-deep fractured tight gas reservoir in piedmont configuration, located in the Cretaceous Bashijiqike Fm of the Tarim Basin, as an example. First, evaluation experiments were conducted on the filtrate invasion, the dynamic damage of oil-based drill-in fluids and the loading capacity of filter cakes. Meanwhile, the evaluating methods were optimized for the formation damage control effect of oil-based drill-in fluids in laboratory: pre-processing drill-in fluids before grading analysis; using the dynamic damage method to simulate the damage process for evaluating the percentage of regained permeability; and evaluating the loading capacity of filter cakes. The experimental results show that (1 oil phase trapping damage and solid phase invasion are the main formation damage types; (2 the damage degree of filtrate is the strongest on the matrix; and (3 the dynamic damage degree of oil-based drill-in fluids reaches medium strong to strong on fractures and filter cakes show a good sealing capacity for the fractures less than 100 μm. In conclusion, the filter cakes' loading capacity should be first guaranteed, and both percentage of regained permeability and liquid trapping damage degree should be both considered in the oil-based drill-in fluids prepared for those ultra-deep fractured tight sandstone gas reservoirs.

Fracture-related fluid flow in sandstone reservoirs - Insights from outcrop analogues of South-eastern Utah

NARCIS (Netherlands)

Ogata, K.; Senger, K.; Braathen, A.; Tveranger, J.; Petrie, E.; Evans, J.P.

2012-01-01

Fault- And fold-related fractures influence the fluid circulation in the subsurface, thus being of high importance for CO2 storage site assessment, especially in terms of reservoir connectivity and leakage. In this context, discrete regions of concentrated sub-parallel fracturing known as fracture

Tracing fluid flow in geothermal reservoirs

Energy Technology Data Exchange (ETDEWEB)

Rose, P.E.; Adams, M.C. [Univ. of Utah, Salt Lake City, UT (United States)

1997-12-31

A family of fluorescent compounds, the polycyclic aromatic sulfonates, were evaluated for application in intermediate- and high-temperature geothermal reservoirs. Whereas the naphthalene sulfonates were found to be very thermally stable and reasonably detectable, the amino-substituted naphthalene sulfonates were found to be somewhat less thermally stable, but much more detectable. A tracer test was conducted at the Dixie Valley, Nevada, geothermal reservoir using one of the substituted naphthalene sulfonates, amino G, and fluorescein. Four of 9 production wells showed tracer breakthrough during the first 200 days of the test. Reconstructed tracer return curves are presented that correct for the thermal decay of tracer assuming an average reservoir temperature of 227{degrees}C. In order to examine the feasibility of using numerical simulation to model tracer flow, we developed simple, two-dimensional models of the geothermal reservoir using the numerical simulation programs TETRAD and TOUGH2. By fitting model outputs to measured return curves, we show that numerical reservoir simulations can be calibrated with the tracer data. Both models predict the same order of elution, approximate tracer concentrations, and return curve shapes. Using these results, we propose a method for using numerical models to design a tracer test.

Bull trout (Salvelinus confluentus) movement in relation to water temperature, season, and habitat features in Arrowrock Reservoir, Idaho, 2012

Science.gov (United States)

Maret, Terry R.; Schultz, Justin E.

2013-01-01

Acoustic telemetry was used to determine spring to summer (April–August) movement and habitat use of bull trout (Salvelinus confluentus) in Arrowrock Reservoir (hereafter “Arrowrock”), a highly regulated reservoir in the Boise River Basin of southwestern Idaho. Water management practices annually use about 86 percent of the reservoir water volume to satisfy downstream water demands. These practices might be limiting bull trout habitat and movement patterns. Bull trout are among the more thermally sensitive coldwater species in North America, and the species is listed as threatened throughout the contiguous United States under the Endangered Species Act. Biweekly water-temperature and dissolved-oxygen profiles were collected by the Bureau of Reclamation at three locations in Arrowrock to characterize habitat conditions for bull trout. Continuous streamflow and water temperature also were measured immediately upstream of the reservoir on the Middle and South Fork Boise Rivers, which influence habitat conditions in the riverine zones of the reservoir. In spring 2012, 18 bull trout ranging in total length from 306 to 630 millimeters were fitted with acoustic transmitters equipped with temperature and depth sensors. Mobile boat tracking and fixed receivers were used to detect released fish. Fish were tagged from March 28 to April 20 and were tracked through most of August. Most bull trout movements were detected in the Middle Fork Boise River arm of the reservoir. Fifteen individual fish were detected at least once after release. Water surface temperature at each fish detection location ranged from 6.0 to 16.2 degrees Celsius (°C) (mean=10.1°C), whereas bull trout body temperatures were colder, ranging from 4.4 to 11.6°C (mean=7.3°C). Bull trout were detected over deep-water habitat, ranging from 8.0 to 42.6 meters (m) (mean=18.1 m). Actual fish depths were shallower than total water depth, ranging from 0.0 to 24.5 m (mean=6.7 m). The last bull trout was

Dielectrophoresis-magnetophoresis force driven magnetic nanoparticle movement in transformer oil based magnetic fluids.

Science.gov (United States)

Lee, Jong-Chul; Lee, Sangyoup

2013-09-01

Magnetic fluid is a stable colloidal mixture contained magnetic nanoparticles coated with a surfactant. Recently, it was found that the fluid has properties to increase heat transfer and dielectric characteristics due to the added magnetic nanoparticles in transformer oils. The magnetic nanoparticles in the fluid experience an electrical force directed toward the place of maximum electric field strength when the electric field is applied. And when the external magnetic field is applied, the magnetic nanoparticles form long chains oriented along the direction of the field. The behaviors of magnetic nanoparticles in both the fields must play an important role in changing the heat transfer and dielectric characteristics of the fluids. In this study, we visualized the movement of magnetic nanoparticles influenced by both the fields applied in-situ. It was found that the magnetic nanoparticles travel in the region near the electrode by the electric field and form long chains along the field direction by the magnetic field. It can be inferred that the movement of magnetic nanoparticles appears by both the fields, and the breakdown voltage of transformer oil based magnetic fluids might be influenced according to the dispersion of magnetic nanoparticles.

Fluid contact monitoring in some western Canadian reefs

International Nuclear Information System (INIS)

Pickel, J.S.; Heslop, A.

1978-01-01

Thirty years have passed since oil was first discovered in reefal reservoirs in the Western Canadian Sedimentary Basin. The early giants such as Redwater, Leduc, and the large Swan Hill pools have been followed in subsequent years by the development of reef pools of declining size, culminating with the discovery of the Keg River reefs of the Rainbow Zama area some 10 years ago. Unfortunately the majority of reef pools are reaching a mature stage in their productive cycle. With this maturity comes an increasing need for the log analyst to diversify his role from merely recognizing hydrocarbons during the discovery process, to the analysis of remaining hydrocarbon distribution within the depleting reservoir. The monitoring of fluid movement has become an integral part of reservoir description. Geologist, log analyst, reservoir and production engineer must work as a coordinated team to explain the often anomalous fluid distributions that occur in the well bore. Oil recovery from the Devonian Leduc age reef at Golden Spike, Alberta has been, until recently, by displacement with a miscible solvent bank. The monitoring of gas--fluid interfaces has been accomplished by the use of pulsed neutron logs in cased holes and the combination of SNP-Density and SNP-Acoustic data in open hole situations. At Judy Creek premature advances of formation water and inefficient reservoir depletion resulted from a highly stratified reefal reservoir. Pulsed neutron logs, used after the recognition of the production problems, have helped define oil-water distributions in the reservoir and led to an improvement in recovery efficiency. Rainbow Devonian Keg River reefs are subjected to gas, miscible and water injection recovery schemes. A pool that has been converted from a primary gas expansion drive to water drive by injection has used the pulsed neutron log to monitor the effectiveness of this change

2D X-ray scanner and its uses in laboratory reservoir characterization measurements

Energy Technology Data Exchange (ETDEWEB)

Maloney, D.; Doggett, K.

1997-08-01

X-ray techniques are used in petroleum laboratories for a variety of reservoir characterization measurements. This paper describes the configuration of a 2D X-ray scanner and many of the ways in which it simplifies and improves accuracy`s of laboratory measurements. Linear X-ray scanners are most often used to provide descriptions of fluid saturations within core plugs during flow tests. We configured our linear scanner for both horizontal and vertical movement. Samples can be scanned horizontally, vertically, or according to horizontal and vertical grids. X-ray measurements are fast, allowing measurements of two- and three-phase fluid saturations during both steady- and unsteady-state flow processes. Rock samples can be scanned while they are subjected to stress, pore pressure, and temperature conditions simulating those of a petroleum reservoir. Many types of measurements are possible by selecting appropriate X-ray power settings, dopes, filters, and collimator configurations. The scanner has been used for a variety of applications besides fluid saturation measurements. It is useful for measuring porosity distributions in rocks, concentrations of X-ray dopes within flow streams during tracer tests, gap widths in fracture flow cells, fluid interface levels in PVT cells and fluid separators, and other features and phenomena.

Peristaltic Transport of a Rheological Fluid: Model for Movement of Food Bolus Through Esophagus

OpenAIRE

Misra, J. C.; Maiti, S.

2011-01-01

Fluid mechanical peristaltic transport through esophagus has been of concern in the paper. A mathematical model has been developed with an aim to study the peristaltic transport of a rheological fluid for arbitrary wave shapes and tube lengths. The Ostwald-de Waele power law of viscous fluid is considered here to depict the non-Newtonian behaviour of the fluid. The model is formulated and analyzed with the specific aim of exploring some important information concerning the movement of food bo...

Movement of fossil pore fluids in granite basement, Illinois

International Nuclear Information System (INIS)

Couture, R.A.; Seitz, M.G.

1986-01-01

The compositions of pore fluids in granite cores from the Precambrian basement in northern Illinois were determined. The estimated chloride concentration in the aqueous phase increases from near zero at the upper contact with sandstone to 2.7 M at 624 m below the contact. Traces of aliphatic oil are present in the overlying sandstone and the upper 516 m of granite, and oil occupies most of the pore space in one sample of unaltered granite 176 m below the contact. The oil has a Δ 13 C of -25%, about the same as average petroleum. The high concentrations of salt more than 500 m below the contact imply that little or no fresh water has reached these levels of the granite by flow. Lower concentrations near the contact are consistent with replacement of brine in the sandstone by fresh water at least 11 m.y. ago and subsequent upward diffusion of salt from the granite. Geologic data suggest that the time of replacement was about 130 Ma. The purpose of the investigation is to study the record of movement of intergranular fluids within a granite pluton. The composition and movement of ground waters can determine the extent that hazardous or radioactive wastes disposed in igneous rock will remain isolated

Computerized X-ray Microtomography Observations and Fluid Flow Measurements of the Effect of Effective Stress on Fractured Reservoir Seal Shale

Science.gov (United States)

Welch, N.; Crawshaw, J.; Boek, E.

2014-12-01

The successful storage of carbon dioxide in geologic formations requires an in-depth understanding of all reservoir characteristics and morphologies. An intact and substantial seal formation above a storage reservoir is required for a significant portion of the initial sealing mechanisms believed to occur during carbon dioxide storage operations. Shales are a common seal formation rock types found above numerous hydrocarbon reservoirs, as well as potential saline aquifer storage locations. Shales commonly have very low permeability, however they also have the tendency to be quite fissile, and the formation of fractures within these seals can have a significant detrimental effect on the sealing potential of a reservoir and amount to large areas of high permeability and low capillary pressures compared to the surrounding intact rock. Fractured shales also have an increased current interest due to the increasing development of shale gas reservoirs using hydraulic fracturing techniques. This work shows the observed changes that occur within fractured pieces of reservoir seal shale samples, along with quarry analogues, using an in-situ micro-CT fluid flow imaging apparatus with a Hassler type core holder. Changes within the preferential flow path under different stress regimes as well as physical changes to the fracture geometry are reported. Lattice Boltzmann flow simulations were then performed on the extracted flow paths and compared to experiment permeability measurements. The preferential flow path of carbon dioxide through the fracture network is also observed and compared to the results two-phase Lattice Boltzmann fluid flow simulations.

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

Apparatus and Methods for Fluid Storage and Delivery

Science.gov (United States)

Parazynski, Scott E. (Inventor); Bue, Grant C. (Inventor); Schaefbauer, Mark E. (Inventor); Urban, Kase C. (Inventor)

2014-01-01

An apparatus and method for storing and delivering fluid to a person comprises, in at least one specific embodiment, a fluid reservoir having an internal volume therein with an opening disposed through a first wall or a second wall of the fluid reservoir and located toward a first end of the fluid reservoir. A first portion of a tube can be exterior to the fluid reservoir and a second portion of the tube can be disposed through the opening and within the internal volume. At least one insulation layer can be disposed about the exterior of the first wall of the fluid reservoir. The second wall of the fluid reservoir can be configured for transferring heat from or to the internal volume or from the person. At least one baffle is disposed within the internal volume and connected to the first wall and the second wall of the fluid reservoir.

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

Final Report: Development of a Chemical Model to Predict the Interactions between Supercritical CO2, Fluid and Rock in EGS Reservoirs

Energy Technology Data Exchange (ETDEWEB)

McPherson, Brian J. [University of Utah; Pan, Feng [University of Utah

2014-09-24

This report summarizes development of a coupled-process reservoir model for simulating enhanced geothermal systems (EGS) that utilize supercritical carbon dioxide as a working fluid. Specifically, the project team developed an advanced chemical kinetic model for evaluating important processes in EGS reservoirs, such as mineral precipitation and dissolution at elevated temperature and pressure, and for evaluating potential impacts on EGS surface facilities by related chemical processes. We assembled a new database for better-calibrated simulation of water/brine/ rock/CO2 interactions in EGS reservoirs. This database utilizes existing kinetic and other chemical data, and we updated those data to reflect corrections for elevated temperature and pressure conditions of EGS reservoirs.

Impact of Reservoir Fluid Saturation on Seismic Parameters: Endrod Gas Field, Hungary

Science.gov (United States)

El Sayed, Abdel Moktader A.; El Sayed, Nahla A.

2017-12-01

Outlining the reservoir fluid types and saturation is the main object of the present research work. 37 core samples were collected from three different gas bearing zones in the Endrod gas field in Hungary. These samples are belonging to the Miocene and the Upper - Lower Pliocene. These samples were prepared and laboratory measurements were conducted. Compression and shear wave velocity were measured using the Sonic Viewer-170-OYO. The sonic velocities were measured at the frequencies of 63 and 33 kHz for compressional and shear wave respectively. All samples were subjected to complete petrophysical investigations. Sonic velocities and mechanical parameters such as young’s modulus, rigidity, and bulk modulus were measured when samples were saturated by 100%-75%-0% brine water. Several plots have been performed to show the relationship between seismic parameters and saturation percentages. Robust relationships were obtained, showing the impact of fluid saturation on seismic parameters. Seismic velocity, Poisson’s ratio, bulk modulus and rigidity prove to be applicable during hydrocarbon exploration or production stages. Relationships among the measured seismic parameters in gas/water fully and partially saturated samples are useful to outline the fluid type and saturation percentage especially in gas/water transitional zones.

Phase Envelope Calculations for Reservoir Fluids in the Presence of Capillary Pressure

DEFF Research Database (Denmark)

Lemus, Diego; Yan, Wei; Michelsen, Michael L.

2015-01-01

the bubble and dew point curves but also other quality lines with vapor fractions between 0 and 1. The algorithm has been used to calculate the phase envelopes of binary, multicomponent and reservoir fluid systems for pore radius from 10 to 50 nm. The presence of capillary pressure changes the saturation...... pressures in the whole phase envelope except at the critical point. The bubble point curve shows a negative change while the dew point curve shows positive and negative changes in the upper dew point branch and the lower dew point branch, respectively. In particular, the cricondentherm is also shifted...

Method of extracting heat from dry geothermal reservoirs

Science.gov (United States)

Potter, R.M.; Robinson, E.S.; Smith, M.C.

1974-01-22

Hydraulic fracturing is used to interconnect two or more holes that penetrate a previously dry geothermal reservoir, and to produce within the reservoir a sufficiently large heat-transfer surface so that heat can be extracted from the reservoir at a usefully high rate by a fluid entering it through one hole and leaving it through another. Introduction of a fluid into the reservoir to remove heat from it and establishment of natural (unpumped) convective circulation through the reservoir to accomplish continuous heat removal are important and novel features of the method. (auth)

The Magnetic Nanoparticle Movement in Magnetic Fluid Characterized by the Laser Dynamic Speckle Interferometry

Directory of Open Access Journals (Sweden)

Xijun Wang

2014-01-01

Full Text Available A dual scanning laser speckle interferometry experiment was designed to observe the dynamic behavior of the magnetic fluid actuated by a magnetic field. In order to improve the spatial resolution of the dynamic speckle measurement, the phase delay scanning was used to compensate the additional phase variation which was caused by the transverse scanning. The correlation coefficients corresponding to the temporal dynamic speckle patterns within the same time interval scattering from the nanoparticles were calculated in the experiment on nanoscale magnetic clusters. In the experiment, the speckle of the magnetic nanoparticle fluid movement has been recorded by the lens unmounted CCD within the interferometry strips, although the speckle led to the distinguished annihilation of the light coherence. The results have showed that the nanoparticle fluid dynamic properties appeared synergistically in the fringe speckles. The analyses of the nanoparticle's relative speed and the speckle pattern moving amount in the fringes have proved the nanoparticle’s movement in a laminar flow in the experiment.

Mapping the Fluid Pathways and Permeability Barriers of a Large Gas Hydrate Reservoir

Science.gov (United States)

Campbell, A.; Zhang, Y. L.; Sun, L. F.; Saleh, R.; Pun, W.; Bellefleur, G.; Milkereit, B.

2012-12-01

An understanding of the relationship between the physical properties of gas hydrate saturated sedimentary basins aids in the detection, exploration and monitoring one of the world's upcoming energy resources. A large gas hydrate reservoir is located in the MacKenzie Delta of the Canadian Arctic and geophysical logs from the Mallik test site are available for the gas hydrate stability zone (GHSZ) between depths of approximately 850 m to 1100 m. The geophysical data sets from two neighboring boreholes at the Mallik test site are analyzed. Commonly used porosity logs, as well as nuclear magnetic resonance, compressional and Stoneley wave velocity dispersion logs are used to map zones of elevated and severely reduced porosity and permeability respectively. The lateral continuity of horizontal permeability barriers can be further understood with the aid of surface seismic modeling studies. In this integrated study, the behavior of compressional and Stoneley wave velocity dispersion and surface seismic modeling studies are used to identify the fluid pathways and permeability barriers of the gas hydrate reservoir. The results are compared with known nuclear magnetic resonance-derived permeability values. The aim of investigating this heterogeneous medium is to map the fluid pathways and the associated permeability barriers throughout the gas hydrate stability zone. This provides a framework for an understanding of the long-term dissociation of gas hydrates along vertical and horizontal pathways, and will improve the knowledge pertaining to the production of such a promising energy source.

The Ahuachapan geothermal field, El Salvador: Reservoir analysis

Energy Technology Data Exchange (ETDEWEB)

Aunzo, Z.; Bodvarsson, G.S.; Laky, C.; Lippmann, M.J.; Steingrimsson, B.; Truesdell, A.H.; Witherspoon, P.A. (Lawrence Berkeley Lab., CA (USA); Icelandic National Energy Authority, Reykjavik (Iceland); Geological Survey, Menlo Park, CA (USA); Lawrence Berkeley Lab., CA (USA))

1989-08-01

The Earth Sciences Division of Lawrence Berkeley Laboratory (LBL) is conducting a reservoir evaluation study of the Ahuachapan geothermal field in El Salvador. This work is being performed in cooperation with the Comision Ejecutiva Hidroelectrica del Rio Lempa (CEL) and the Los Alamos National Laboratory (LANL). This report describes the work done during the first year of the study (FY 1988--89), and includes the (1) development of geological and conceptual models of the field, (2) evaluation of the initial thermodynamic and chemical conditions and their changes during exploitation, (3) evaluation of interference test data and the observed reservoir pressure decline, and (4) the development of a natural state model for the field. The geological model of the field indicates that there are seven (7) major and five (5) minor faults that control the fluid movement in the Ahuachapan area. Some of the faults act as a barrier to flow as indicated by large temperature declines towards the north and west. Other faults act as preferential pathways to flow. The Ahuachapan Andesites provide good horizontal permeability to flow and provide most of the fluids to the wells. The underlying Older Agglomerates also contribute to well production, but considerably less than the Andesites. 84 refs.

Integrated 3D Reservoir/Fault Property Modelling Aided Well Planning and Improved Hydrocarbon Recovery in a Niger Delta Field

International Nuclear Information System (INIS)

Onyeagoro, U. O.; Ebong, U. E.; Nworie, E. A.

2002-01-01

The large and varied portfolio of assets managed by oil companies requires quick decision-making and the deployment of best in class technologies in asset management. Timely decision making and the application of the best technologies in reservoir management are however sometimes in conflict due to large time requirements of the latter.Optimizing the location of development wells is critical to account for variable fluid contact movements and pressure interference effects between wells, which can be significant because of the high permeability (Darcy range) of Niger Delta reservoirs. With relatively high drilling costs, the optimization of well locations necessitates a good realistic static and dynamic 3D reservoir description, especially in the recovery of remaining oil and oil rim type of reservoirs.A detailed 3D reservoir model with fault properties was constructed for a Niger delta producing field. This involved the integration of high quality 3D seismic, core, petrophysics, reservoir engineering, production and structural geology data to construct a realistic 3D reservoir/fault property model for the field. The key parameters considered during the construction of the internal architecture of the model were the vertical and horizontal reservoir heterogeneities-this controls the fluid flow within the reservoir. In the production realm, the fault thickness and fault permeabilities are factors that control the impedance of fluid flow across the fault-fault transmissibility. These key internal and external reservoir/structural variables were explicitly modeled in a 3D modeling software to produce different realizations and manage the uncertainties.The resulting 3D reservoir/fault property model was upscaled for simulation purpose such that grid blocks along the fault planes have realistic transmissibility multipliers of 0 to 1 attached to them. The model was also used in the well planner to optimize the positioning of a high angle deviated well that penetrated

The influence of open fracture anisotropy on CO2 movement within geological storage complexes

Science.gov (United States)

Bond, C. E.; Wightman, R.; Ringrose, P. S.

2012-12-01

Carbon mitigation through the geological storage of carbon dioxide is dependent on the ability of geological formations to store CO2 trapping it within a geological storage complex. Secure long-term containment needs to be demonstrated, due to both political and social drivers, meaning that this containment must be verifiable over periods of 100-105 years. The effectiveness of sub-surface geological storage systems is dependent on trapping CO2 within a volume of rock and is reliant on the integrity of the surrounding rocks, including their chemical and physical properties, to inhibit migration to the surface. Oil and gas reservoir production data, and field evidence show that fracture networks have the potential to act as focused pathways for fluid movement. Fracture networks can allow large volumes of fluid to migrate to the surface within the time scales of interest. In this paper we demonstrate the importance of predicting the effects of fracture networks in storage, using a case study from the In Salah CO2 storage site, and show how the fracture permeability is closely controlled by the stress regime that determines the open fracture network. Our workflow combines well data of imaged fractures, with a discrete fracture network (DFN) model of tectonically induced fractures, within the horizon of interest. The modelled and observed fractures have been compared and combined with present day stress data to predict the open fracture network and its implications for anisotropic movement of CO2 in the sub-surface. The created fracture network model has been used to calculate the 2D permeability tensor for the reservoir for two scenarios: 1) a model in which all fractures are permeable, based on the whole DFN model and 2) those fractures determined to be in dilatational failure under the present day stress regime, a sub-set of the DFN. The resulting permeability anisotropy tensors show distinct anisotropies for the predicted CO2 movement within the reservoir. These

Field demonstration of an active reservoir pressure management through fluid injection and displaced fluid extractions at the Rock Springs Uplift, a priority geologic CO₂ storage site for Wyoming

Energy Technology Data Exchange (ETDEWEB)

Jiao, Zunsheng [Univ. of Wyoming, Laramie, WY (United States)

2017-04-05

This report provides the results from the project entitled Field Demonstration of Reservoir Pressure Management through Fluid Injection and Displaced Fluid Extraction at the Rock Springs Uplift, a Priority Geologic CO2 Storage Site for Wyoming (DE-FE0026159 for both original performance period (September 1, 2015 to August 31, 2016) and no-cost extension (September 1, 2016 to January 6, 2017)).

Fluid jet electric discharge source

Science.gov (United States)

Bender, Howard A [Ripon, CA

2006-04-25

A fluid jet or filament source and a pair of coaxial high voltage electrodes, in combination, comprise an electrical discharge system to produce radiation and, in particular, EUV radiation. The fluid jet source is composed of at least two serially connected reservoirs, a first reservoir into which a fluid, that can be either a liquid or a gas, can be fed at some pressure higher than atmospheric and a second reservoir maintained at a lower pressure than the first. The fluid is allowed to expand through an aperture into a high vacuum region between a pair of coaxial electrodes. This second expansion produces a narrow well-directed fluid jet whose size is dependent on the size and configuration of the apertures and the pressure used in the reservoir. At some time during the flow of the fluid filament, a high voltage pulse is applied to the electrodes to excite the fluid to form a plasma which provides the desired radiation; the wavelength of the radiation being determined by the composition of the fluid.

Pore Characterization of Shale Rock and Shale Interaction with Fluids at Reservoir Pressure-Temperature Conditions Using Small-Angle Neutron Scattering

Science.gov (United States)

Ding, M.; Hjelm, R.; Watkins, E.; Xu, H.; Pawar, R.

2015-12-01

Oil/gas produced from unconventional reservoirs has become strategically important for the US domestic energy independence. In unconventional realm, hydrocarbons are generated and stored in nanopores media ranging from a few to hundreds of nanometers. Fundamental knowledge of coupled thermo-hydro-mechanical-chemical (THMC) processes that control fluid flow and propagation within nano-pore confinement is critical for maximizing unconventional oil/gas production. The size and confinement of the nanometer pores creates many complex rock-fluid interface interactions. It is imperative to promote innovative experimental studies to decipher physical and chemical processes at the nanopore scale that govern hydrocarbon generation and mass transport of hydrocarbon mixtures in tight shale and other low permeability formations at reservoir pressure-temperature conditions. We have carried out laboratory investigations exploring quantitative relationship between pore characteristics of the Wolfcamp shale from Western Texas and the shale interaction with fluids at reservoir P-T conditions using small-angle neutron scattering (SANS). We have performed SANS measurements of the shale rock in single fluid (e.g., H2O and D2O) and multifluid (CH4/(30% H2O+70% D2O)) systems at various pressures up to 20000 psi and temperature up to 150 oF. Figure 1 shows our SANS data at different pressures with H2O as the pressure medium. Our data analysis using IRENA software suggests that the principal changes of pore volume in the shale occurred on smaller than 50 nm pores and pressure at 5000 psi (Figure 2). Our results also suggest that with increasing P, more water flows into pores; with decreasing P, water is retained in the pores.

Development of a cerebrospinal fluid lateral reservoir model in rhesus monkeys (Macaca mulatta).

Science.gov (United States)

Lester McCully, Cynthia M; Bacher, John; MacAllister, Rhonda P; Steffen-Smith, Emilie A; Saleem, Kadharbatcha; Thomas, Marvin L; Cruz, Rafael; Warren, Katherine E

2015-02-01

Rapid, serial, and humane collection of cerebrospinal fluid (CSF) in nonhuman primates (NHP) is an essential element of numerous research studies and is currently accomplished via two different models. The CSF reservoir model (FR) combines a catheter in the 4th ventricle with a flexible silastic reservoir to permit circulating CSF flow. The CSF lateral port model (LP) consists of a lateral ventricular catheter and an IV port that provides static access to CSF and volume restrictions on sample collection. The FR model is associated with an intensive, prolonged recovery and frequent postsurgical hydrocephalus and nonpatency, whereas the LP model is associated with an easier recovery. To maximize the advantages of both systems, we developed the CSF lateral reservoir model (LR), which combines the beneficial features of the 2 previous models but avoids their limitations by using a reservoir for circulating CSF flow combined with catheter placement in the lateral ventricle. Nine adult male rhesus monkeys were utilized in this study. Pre-surgical MRI was performed to determine the coordinates of the lateral ventricle and location of choroid plexus (CP). The coordinates were determined to avoid the CP and major blood vessels. The predetermined coordinates were 100% accurate, according to MRI validation. The LR system functioned successfully in 67% of cases for 221 d, and 44% remain functional at 426 to 510 d postoperatively. Compared with established models, our LR model markedly reduced postoperative complications and recovery time. Development of the LR model was successful in rhesus macaques and is a useful alternative to the FR and LP methods of CSF collection from nonhuman primates.

Use of TOUGHREACT to Simulate Effects of Fluid Chemistry onInjectivity in Fractured Geothermal Reservoirs with High Ionic StrengthFluids

Energy Technology Data Exchange (ETDEWEB)

Xu, Tianfu; Zhang, Guoxiang; Pruess, Karsten

2005-02-09

Recent studies suggest that mineral dissolution/precipitation and clay swelling effects could have a major impact on the performance of hot dry rock (HDR) and hot fractured rock (HFR) reservoirs. A major concern is achieving and maintaining adequate injectivity, while avoiding the development of preferential short-circuiting flow paths. A Pitzer ionic interaction model has been introduced into the publicly available TOUGHREACT code for solving non-isothermal multi-phase reactive geochemical transport problems under conditions of high ionic strength, expected in typical HDR and HFR systems. To explore chemically-induced effects of fluid circulation in these systems, we examine ways in which the chemical composition of reinjected waters can be modified to improve reservoir performance. We performed a number of coupled thermo-hydrologic-chemical simulations in which the fractured medium was represented by a one-dimensional MINC model (multiple interacting continua). Results obtained with the Pitzer activity coefficient model were compared with those using an extended Debye-Hueckel equation. Our simulations show that non-ideal activity effects can be significant even at modest ionic strength, and can have major impacts on permeability evolution in injection-production systems. Alteration of injection water chemistry, for example by dilution with fresh water, can greatly alter precipitation and dissolution effects, and can offer a powerful tool for operating hot dry rock and hot fractured rock reservoirs in a sustainable manner.

Improving reservoir history matching of EM heated heavy oil reservoirs via cross-well seismic tomography

KAUST Repository

Katterbauer, Klemens; Hoteit, Ibrahim

2014-01-01

process. While becoming a promising technology for heavy oil recovery, its effect on overall reservoir production and fluid displacements are poorly understood. Reservoir history matching has become a vital tool for the oil & gas industry to increase

Geothermal energy production with supercritical fluids

Science.gov (United States)

Brown, Donald W.

2003-12-30

There has been invented a method for producing geothermal energy using supercritical fluids for creation of the underground reservoir, production of the geothermal energy, and for heat transport. Underground reservoirs are created by pumping a supercritical fluid such as carbon dioxide into a formation to fracture the rock. Once the reservoir is formed, the same supercritical fluid is allowed to heat up and expand, then is pumped out of the reservoir to transfer the heat to a surface power generating plant or other application.

Estimation of original reservoir fluid composition prior to aquifer boiling induced by well discharge. Kieki niso ryunyu ni okeru choryu sonai futto izen no chinetsu ryutai no kagaku soshiki no suiteiho

Energy Technology Data Exchange (ETDEWEB)

Seki, Y [Geological Survey of Japan, Tsukuba (Japan)

1991-07-29

A method for estimating chemical composition of original fluid before boiling from the composition of whole fluid flowing into a well is described for the case where an aquifer boiling has begun in a reservoir bed associated with discharge of geothermal fluid from the well (the enthalpy of fluid flowing into the well is larger than an enthalpy possessed by a hot fluid-phase saturated by steam at measured temperatures at flowing point). In this case, it is especially pointed out that the gas-liquid ratio at the well flow-in point becomes larger than the one at boiling. The boiling in the reservoir bed is modelled into two types. One is for larger coefficient of permeation in the reservoir bed where the discharge flow at the well is large, the temperature drop around the well is small, and the boiling is in single stage. The other is for smaller coefficient of permeation in the reservoir bed where the discharge flow and temperature drop are contrastive to the former case, and the boiling is in multi-stage. Calculation processes based on this boiling model are explained with calculation examples. 8 refs.,7 figs.

Understanding the True Stimulated Reservoir Volume in Shale Reservoirs

KAUST Repository

Hussain, Maaruf

2017-06-06

Successful exploitation of shale reservoirs largely depends on the effectiveness of hydraulic fracturing stimulation program. Favorable results have been attributed to intersection and reactivation of pre-existing fractures by hydraulically-induced fractures that connect the wellbore to a larger fracture surface area within the reservoir rock volume. Thus, accurate estimation of the stimulated reservoir volume (SRV) becomes critical for the reservoir performance simulation and production analysis. Micro-seismic events (MS) have been commonly used as a proxy to map out the SRV geometry, which could be erroneous because not all MS events are related to hydraulic fracture propagation. The case studies discussed here utilized a fully 3-D simulation approach to estimate the SRV. The simulation approach presented in this paper takes into account the real-time changes in the reservoir\\'s geomechanics as a function of fluid pressures. It is consisted of four separate coupled modules: geomechanics, hydrodynamics, a geomechanical joint model for interfacial resolution, and an adaptive re-meshing. Reservoir stress condition, rock mechanical properties, and injected fluid pressure dictate how fracture elements could open or slide. Critical stress intensity factor was used as a fracture criterion governing the generation of new fractures or propagation of existing fractures and their directions. Our simulations were run on a Cray XC-40 HPC system. The studies outcomes proved the approach of using MS data as a proxy for SRV to be significantly flawed. Many of the observed stimulated natural fractures are stress related and very few that are closer to the injection field are connected. The situation is worsened in a highly laminated shale reservoir as the hydraulic fracture propagation is significantly hampered. High contrast in the in-situ stresses related strike-slip developed thereby shortens the extent of SRV. However, far field nature fractures that were not connected to

Analysis of pressure falloff tests of non-Newtonian power-law fluids in naturally-fractured bounded reservoirs

Directory of Open Access Journals (Sweden)

Omotayo Omosebi

2015-12-01

This article presents an analytic technique for interpreting pressure falloff tests of non-Newtonian Power-law fluids in wells that are located near boundaries in dual-porosity reservoirs. First, dimensionless pressure solutions are obtained and Stehfest inversion algorithm is used to develop new type curves. Subsequently, long-time analytic solutions are presented and interpretation procedure is proposed using direct synthesis. Two examples, including real field data from a heavy oil reservoir in Colombian eastern plains basin, are used to validate and demonstrate application of this technique. Results agree with conventional type-curve matching procedure. The approach proposed in this study avoids the use of type curves, which is prone to human errors. It provides a better alternative for direct estimation of formation and flow properties from falloff data.

Movement of 125I albumin and 125I polyvinylpyrrolidone through bone tissue fluid

International Nuclear Information System (INIS)

Owen, M.; Howlett, C.R.; Triffitt, J.T.

1977-01-01

The passage of tissue fluid through cortical bone has been investigated using radioactively labelled macromolocules as markers. The results suggest that in the cortex of young rabbit femur the movement of tissue fluid is in the same net direction as blood, mainly from the endosteal to the periosteal surface. Some albumin is incorporated from extravascular tissue fluid into calcified matrix at sites of bone formation. Polyvinylpyrrolidone, average molecular weight 35,000, is able to pass through extravascular tissue fluid in bone but is not incorporated into calcified matrix. In rabbits made vitamin D deficient, much less albumin is retained in regions of bone formation than is the case with controls. Albumin adsorbs to the surface of calcium phosphate precipitates, and it is suggested that this mechanism may be mainly responsible for its incorporation into bone. (orig.) 891 AJ [de

Natural radium and radon tracers to quantify water exchange and movement in reservoirs

Science.gov (United States)

Smith, Christopher G.; Baskaran, Mark

2011-01-01

Radon and radium isotopes are routinely used to quantify exchange rates between different hydrologic reservoirs. Since their recognition as oceanic tracers in the 1960s, both radon and radium have been used to examine processes such as air-sea exchange, deep oceanic mixing, benthic inputs, and many others. Recently, the application of radon-222 and the radium-quartet (223,224,226,228Ra) as coastal tracers has seen a revelation with the growing interest in coastal groundwater dynamics. The enrichment of these isotopes in benthic fluids including groundwater makes both radium and radon ideal tracers of coastal benthic processes (e.g. submarine groundwater discharge). In this chapter we review traditional and recent advances in the application of radon and radium isotopes to understand mixing and exchange between various hydrologic reservoirs, specifically: (1) atmosphere and ocean, (2) deep and shallow oceanic water masses, (3) coastal groundwater/benthic pore waters and surface ocean, and (4) aquifer-lakes. While the isotopes themselves and their distribution in the environment provide qualitative information about the exchange processes, it is mixing/exchange and transport models for these isotopes that provide specific quantitative information about these processes. Brief introductions of these models and mixing parameters are provided for both historical and more recent studies.

Geochemistry of formation waters from the Wolfcamp and “Cline” shales: Insights into brine origin, reservoir connectivity, and fluid flow in the Permian Basin, USA

Science.gov (United States)

Engle, Mark A.; Reyes, Francisco R.; Varonka, Matthew S.; Orem, William H.; Lin, Ma; Ianno, Adam J.; Westphal, Tiffani M.; Xu, Pei; Carroll, Kenneth C.

2016-01-01

Despite being one of the most important oil producing provinces in the United States, information on basinal hydrogeology and fluid flow in the Permian Basin of Texas and New Mexico is lacking. The source and geochemistry of brines from the basin were investigated (Ordovician- to Guadalupian-age reservoirs) by combining previously published data from conventional reservoirs with geochemical results for 39 new produced water samples, with a focus on those from shales. Salinity of the Ca–Cl-type brines in the basin generally increases with depth reaching a maximum in Devonian (median = 154 g/L) reservoirs, followed by decreases in salinity in the Silurian (median = 77 g/L) and Ordovician (median = 70 g/L) reservoirs. Isotopic data for B, O, H, and Sr and ion chemistry indicate three major types of water. Lower salinity fluids (100 g/L), isotopically heavy (O and H) water in Leonardian [Permian] to Pennsylvanian reservoirs (2–3.2 km depth) is evaporated, Late Permian seawater. Water from the Permian Wolfcamp and Pennsylvanian “Cline” shales, which are isotopically similar but lower in salinity and enriched in alkalis, appear to have developed their composition due to post-illitization diffusion into the shales. Samples from the “Cline” shale are further enriched with NH4, Br, I and isotopically light B, sourced from the breakdown of marine kerogen in the unit. Lower salinity waters (3 km depth), which plot near the modern local meteoric water line, are distinct from the water in overlying reservoirs. We propose that these deep meteoric waters are part of a newly identified hydrogeologic unit: the Deep Basin Meteoric Aquifer System. Chemical, isotopic, and pressure data suggest that despite over-pressuring in the Wolfcamp shale, there is little potential for vertical fluid migration to the surface environment via natural conduits.

Estimation of Dry Fracture Weakness, Porosity, and Fluid Modulus Using Observable Seismic Reflection Data in a Gas-Bearing Reservoir

Science.gov (United States)

Chen, Huaizhen; Zhang, Guangzhi

2017-05-01

Fracture detection and fluid identification are important tasks for a fractured reservoir characterization. Our goal is to demonstrate a direct approach to utilize azimuthal seismic data to estimate fluid bulk modulus, porosity, and dry fracture weaknesses, which decreases the uncertainty of fluid identification. Combining Gassmann's (Vier. der Natur. Gesellschaft Zürich 96:1-23, 1951) equations and linear-slip model, we first establish new simplified expressions of stiffness parameters for a gas-bearing saturated fractured rock with low porosity and small fracture density, and then we derive a novel PP-wave reflection coefficient in terms of dry background rock properties (P-wave and S-wave moduli, and density), fracture (dry fracture weaknesses), porosity, and fluid (fluid bulk modulus). A Bayesian Markov chain Monte Carlo nonlinear inversion method is proposed to estimate fluid bulk modulus, porosity, and fracture weaknesses directly from azimuthal seismic data. The inversion method yields reasonable estimates in the case of synthetic data containing a moderate noise and stable results on real data.

Development of Reservoir Characterization Techniques and Production Models for Exploiting Naturally Fractured Reservoirs

Energy Technology Data Exchange (ETDEWEB)

Wiggins, Michael L.; Brown, Raymon L.; Civan, Frauk; Hughes, Richard G.

2001-08-15

Research continues on characterizing and modeling the behavior of naturally fractured reservoir systems. Work has progressed on developing techniques for estimating fracture properties from seismic and well log data, developing naturally fractured wellbore models, and developing a model to characterize the transfer of fluid from the matrix to the fracture system for use in the naturally fractured reservoir simulator.

Integration of rock typing methods for carbonate reservoir characterization

International Nuclear Information System (INIS)

Aliakbardoust, E; Rahimpour-Bonab, H

2013-01-01

Reservoir rock typing is the most important part of all reservoir modelling. For integrated reservoir rock typing, static and dynamic properties need to be combined, but sometimes these two are incompatible. The failure is due to the misunderstanding of the crucial parameters that control the dynamic behaviour of the reservoir rock and thus selecting inappropriate methods for defining static rock types. In this study, rock types were defined by combining the SCAL data with the rock properties, particularly rock fabric and pore types. First, air-displacing-water capillary pressure curues were classified because they are representative of fluid saturation and behaviour under capillary forces. Next the most important rock properties which control the fluid flow and saturation behaviour (rock fabric and pore types) were combined with defined classes. Corresponding petrophysical properties were also attributed to reservoir rock types and eventually, defined rock types were compared with relative permeability curves. This study focused on representing the importance of the pore system, specifically pore types in fluid saturation and entrapment in the reservoir rock. The most common tests in static rock typing, such as electrofacies analysis and porosity–permeability correlation, were carried out and the results indicate that these are not appropriate approaches for reservoir rock typing in carbonate reservoirs with a complicated pore system. (paper)

Seismic modeling of acid-gas injection in a deep saline reservoir

Energy Technology Data Exchange (ETDEWEB)

Ursenbach, C.P.; Lawton, D.C. [Calgary Univ., AB (Canada). Dept. of Geoscience, Consortium for Research in Elastic Wave Exploration Seismology

2008-07-01

Carbon dioxide (CO{sub 2}) and hydrogen sulfide (H{sub 2}S) are common byproducts of the energy industry. As such, remediation studies are underway to determine the feasibility of sequestering these byproducts in subsurface reservoirs, including deep saline reservoirs. Acid gas injection at smaller gas wells holds promise. However, in order for such injection programs to work, the progress of the injection plume must be tracked. A modeling study of fluid substitution was carried out to gain insight into the ability of seismic monitoring to distinguish pre- and post-injection states of the reservoir medium. The purpose of this study was to carry out fluid substitution calculations for the modeling of an injection process. A methodology that may be applied or adapted to a variety of acid-gas injection scenarios was also developed. The general approach involved determining acoustic properties at reservoir temperature and pressure of relevant fluids; obtaining elastic properties of the reservoir rock for some reference saturated state, and the elastic properties of the mineral comprising it; and, determining the change in reservoir elastic properties due to fluid substitution via Gassmann's equation. Water, brine and non-aqueous acid gas were the 3 fluids of interest in this case. The feasibility of monitoring was judged by the sensitivity of travel times and reflection coefficients to fluid substitution. 4 refs., 2 figs.

Oral fluoride reservoirs and the prevention of dental caries.

Science.gov (United States)

Vogel, Gerald Lee

2011-01-01

Current models for increasing the anti-caries effects of fluoride (F) agents emphasize the importance of maintaining a cariostatic concentration of F in oral fluids. The concentration of F in oral fluids is maintained by the release of this ion from bioavailable reservoirs on the teeth, oral mucosa and - most importantly, because of its association with the caries process - dental plaque. Oral F reservoirs appear to be of two types: (1) mineral reservoirs, in particular calcium fluoride or phosphate-contaminated 'calcium-fluoride-like' deposits; (2) biological reservoirs, in particular (with regard to dental plaque) F held to bacteria or bacterial fragments via calcium-fluoride bonds. The fact that all these reservoirs are mediated by calcium implies that their formation is limited by the low concentration of calcium in oral fluids. By using novel procedures which overcome this limitation, the formation of these F reservoirs after topical F application can be greatly increased. Although these increases are associated with substantive increases in salivary and plaque fluid F, and hence a potential increase in cariostatic effect, it is unclear if such changes are related to the increases in the amount of these reservoirs, or changes in the types of F deposits formed. New techniques have been developed for identifying and quantifying these deposits which should prove useful in developing agents that enhance formation of oral F reservoirs with optimum F release characteristics. Such research offers the prospect of decreasing the F content of topical agents while simultaneously increasing their cariostatic effect. Copyright © 2011 S. Karger AG, Basel.

Fluid flow behaviour of gas-condensate and near-miscible fluids at the pore scale

Energy Technology Data Exchange (ETDEWEB)

Dawe, Richard A. [Department of Chemical Engineering, University of West Indies, St. Augustine (Trinidad and Tobago); Grattoni, Carlos A. [Department of Earth Science and Engineering, Imperial College, London, SW7 2BP (United Kingdom)

2007-02-15

Retrograde condensate reservoir behaviour is complex with much of the detailed mechanisms of the multiphase fluid transport and mass transfer between the phases within the porous matrix still speculative. Visual modelling of selected processes occurring at the pore level under known and controlled boundary conditions can give an insight to fluid displacements at the core scale and help the interpretation of production behaviour at reservoir scale. Visualisation of the pore scale two-phase flow mechanisms has been studied experimentally at low interfacial tensions, < 0.5 mN/m, using a partially miscible fluid system in glass visual micro models. As the interfacial tension decreases the balance between fluid-fluid forces (interfacial, spreading and viscous) and fluid-solid interactions (wettability and viscous interactions) changes. Data measurements in the laboratory, particularly relative permeability, will therefore always be difficult especially for condensate fluids just below their dew point. What is certain is that gas production from a gas-condensate leads to condensate dropout when pressure falls below the dew point, either within the wellbore or, more importantly, in the reservoir. This paper illustrates some pore scale physics, particularly interfacial phenomena at low interfacial tension, which has relevance to appreciating the flow of condensate fluids close to their dew point either near the wellbore (which affects well productivity) or deep inside the reservoir (which affects condensate recovery). (author)

Time lapse seismic observations and effects of reservoir compressibility at Teal South oil field

Science.gov (United States)

Islam, Nayyer

corrected for, indicate water encroachment at the base of the producing reservoir. I also identify specific sites of leakage from various unproduced reservoirs, the result of regional pressure blowdown as explained in previous studies; those earlier studies, however, were unable to identify direct evidence of fluid movement. Of particular interest is the identification of one site where oil apparently leaked from one reservoir into a "new" reservoir that did not originally contain oil, but was ideally suited as a trap for fluids leaking from the neighboring spill-point. With continued pressure drop, oil in the new reservoir increased as more oil entered into the reservoir and expanded, liberating gas from solution. Because of the limited volume available for oil and gas in that temporary trap, oil and gas also escaped from it into the surrounding formation. I also note that some of the reservoirs demonstrate time-lapse changes only in the "gas cap" and not in the oil zone, even though gas must be coming out of solution everywhere in the reservoir. This is explained by interplay between pore-fluid modulus reduction by gas saturation decrease and dry-frame modulus increase by frame stiffening. In the second part of this work, I examine various rock-physics models in an attempt to quantitatively account for frame-stiffening that results from reduced pore-fluid pressure in the producing reservoir, searching for a model that would predict the unusual AVO features observed in the time-lapse prestack and stacked data at Teal South. While several rock-physics models are successful at predicting the time-lapse response for initial production, most fail to match the observations for continued production between Phase I and Phase II. Because the reservoir was initially overpressured and unconsolidated, reservoir compaction was likely significant, and is probably accomplished largely by uniaxial strain in the vertical direction; this implies that an anisotropic model may be required

Phase Behaviors of Reservoir Fluids with Capillary Eff ect Using Particle Swarm Optimization

KAUST Repository

Ma, Zhiwei

2013-05-06

The study of phase behavior is important for the oil and gas industry. Many approaches have been proposed and developed for phase behavior calculation. In this thesis, an alternative method is introduced to study the phase behavior by means of minimization of Helmholtz free energy. For a system at fixed volume, constant temperature and constant number of moles, the Helmholtz free energy reaches minimum at the equilibrium state. Based on this theory, a stochastic method called Particle Swarm Optimization (PSO) algorithm, is implemented to compute the phase diagrams for several pure component and mixture systems. After comparing with experimental and the classical PT-ash calculation, we found the phase diagrams obtained by minimization of the Helmholtz Free Energy approach match the experimental and theoretical diagrams very well. Capillary effect is also considered in this thesis because it has a significant influence on the phase behavior of reservoir fluids. In this part, we focus on computing the phase envelopes, which consists of bubble and dew point lines. Both fixed and calculated capillary pressure from the Young-Laplace equation cases are introduced to study their effects on phase envelopes. We found that the existence of capillary pressure will change the phase envelopes. Positive capillary pressure reduces the dew point and bubble point temperatures under the same pressure condition, while the negative capillary pressure increases the dew point and bubble point temperatures. In addition, the change of contact angle and pore radius will affect the phase envelope. The effect of the pore radius on the phase envelope is insignificant when the radius is very large. These results may become reference for future research and study. Keywords: Phase Behavior; Particle Swarm Optimization; Capillary Pressure; Reservoir Fluids; Phase Equilibrium; Phase Envelope.

Phase Behaviors of Reservoir Fluids with Capillary Eff ect Using Particle Swarm Optimization

KAUST Repository

Ma, Zhiwei

2013-01-01

The study of phase behavior is important for the oil and gas industry. Many approaches have been proposed and developed for phase behavior calculation. In this thesis, an alternative method is introduced to study the phase behavior by means of minimization of Helmholtz free energy. For a system at fixed volume, constant temperature and constant number of moles, the Helmholtz free energy reaches minimum at the equilibrium state. Based on this theory, a stochastic method called Particle Swarm Optimization (PSO) algorithm, is implemented to compute the phase diagrams for several pure component and mixture systems. After comparing with experimental and the classical PT-ash calculation, we found the phase diagrams obtained by minimization of the Helmholtz Free Energy approach match the experimental and theoretical diagrams very well. Capillary effect is also considered in this thesis because it has a significant influence on the phase behavior of reservoir fluids. In this part, we focus on computing the phase envelopes, which consists of bubble and dew point lines. Both fixed and calculated capillary pressure from the Young-Laplace equation cases are introduced to study their effects on phase envelopes. We found that the existence of capillary pressure will change the phase envelopes. Positive capillary pressure reduces the dew point and bubble point temperatures under the same pressure condition, while the negative capillary pressure increases the dew point and bubble point temperatures. In addition, the change of contact angle and pore radius will affect the phase envelope. The effect of the pore radius on the phase envelope is insignificant when the radius is very large. These results may become reference for future research and study. Keywords: Phase Behavior; Particle Swarm Optimization; Capillary Pressure; Reservoir Fluids; Phase Equilibrium; Phase Envelope.

WETTABILITY AND PREDICTION OF OIL RECOVERY FROM RESERVOIRS DEVELOPED WITH MODERN DRILLING AND COMPLETION FLUIDS

Energy Technology Data Exchange (ETDEWEB)

Jill S. Buckley; Norman R. Morrow

2006-01-01

The objectives of this project are: (1) to improve understanding of the wettability alteration of mixed-wet rocks that results from contact with the components of synthetic oil-based drilling and completion fluids formulated to meet the needs of arctic drilling; (2) to investigate cleaning methods to reverse the wettability alteration of mixed-wet cores caused by contact with these SBM components; and (3) to develop new approaches to restoration of wetting that will permit the use of cores drilled with SBM formulations for valid studies of reservoir properties.

Fracture Propagation, Fluid Flow, and Geomechanics of Water-Based Hydraulic Fracturing in Shale Gas Systems and Electromagnetic Geophysical Monitoring of Fluid Migration

Energy Technology Data Exchange (ETDEWEB)

Kim, Jihoon; Um, Evan; Moridis, George

2014-12-01

We investigate fracture propagation induced by hydraulic fracturing with water injection, using numerical simulation. For rigorous, full 3D modeling, we employ a numerical method that can model failure resulting from tensile and shear stresses, dynamic nonlinear permeability, leak-off in all directions, and thermo-poro-mechanical effects with the double porosity approach. Our numerical results indicate that fracture propagation is not the same as propagation of the water front, because fracturing is governed by geomechanics, whereas water saturation is determined by fluid flow. At early times, the water saturation front is almost identical to the fracture tip, suggesting that the fracture is mostly filled with injected water. However, at late times, advance of the water front is retarded compared to fracture propagation, yielding a significant gap between the water front and the fracture top, which is filled with reservoir gas. We also find considerable leak-off of water to the reservoir. The inconsistency between the fracture volume and the volume of injected water cannot properly calculate the fracture length, when it is estimated based on the simple assumption that the fracture is fully saturated with injected water. As an example of flow-geomechanical responses, we identify pressure fluctuation under constant water injection, because hydraulic fracturing is itself a set of many failure processes, in which pressure consistently drops when failure occurs, but fluctuation decreases as the fracture length grows. We also study application of electromagnetic (EM) geophysical methods, because these methods are highly sensitive to changes in porosity and pore-fluid properties due to water injection into gas reservoirs. Employing a 3D finite-element EM geophysical simulator, we evaluate the sensitivity of the crosswell EM method for monitoring fluid movements in shaly reservoirs. For this sensitivity evaluation, reservoir models are generated through the coupled flow

Similar expression of through-and-through fluid movement along orthograde apical plugs of MTA Bio and white Portland cement.

Science.gov (United States)

De-Deus, G; Audi, C; Murad, C; Fidel, S; Fidel, R

2008-12-01

To compare the sealing ability of four hydraulic cements when used as an apical plug in teeth with wide-open apices. A sample of 70 maxillary central incisors were divided into four groups (n = 15) and a further 10 teeth served as controls. An artificial open apex was created in the teeth using Gates Glidden drills numbers 6-1 in a crown-down manner until the size 1 bur passed through the foramen. A divergent open apex was prepared to a size of 1.24 mm at the foramen by retrograde apical transportation using a number 8 (0.60) Profile Series 29 0.4 taper instrument inserted to the length of the cutting blade. In G1, the open apices were repaired with WMTA Angelus whilst in G2, G3 and G4 MTA Bio, Pro-Root MTA and Portland cement was employed respectively. Each root was assembled in a hermetic cell to allow the evaluation of fluid filtration. Leakage was measured by the movement of an air bubble travelling within a pipette connected to the teeth. Measurements of the air bubble movement were made after 10 min at a constant pressure of 50 cm H(2)O. The Kruskal-Wallis H-test was applied to the fluid flow data to detect differences between the experimental groups (P 0.05). Fluid movement through teeth with open apices and filled with four hydraulic cements was similar. All cements allowed fluid movement.

The role of reservoir characterization in the reservoir management process (as reflected in the Department of Energy`s reservoir management demonstration program)

Energy Technology Data Exchange (ETDEWEB)

Fowler, M.L. [BDM-Petroleum Technologies, Bartlesville, OK (United States); Young, M.A.; Madden, M.P. [BDM-Oklahoma, Bartlesville, OK (United States)] [and others

1997-08-01

Optimum reservoir recovery and profitability result from guidance of reservoir practices provided by an effective reservoir management plan. Success in developing the best, most appropriate reservoir management plan requires knowledge and consideration of (1) the reservoir system including rocks, and rock-fluid interactions (i.e., a characterization of the reservoir) as well as wellbores and associated equipment and surface facilities; (2) the technologies available to describe, analyze, and exploit the reservoir; and (3) the business environment under which the plan will be developed and implemented. Reservoir characterization is the essential to gain needed knowledge of the reservoir for reservoir management plan building. Reservoir characterization efforts can be appropriately scaled by considering the reservoir management context under which the plan is being built. Reservoir management plans de-optimize with time as technology and the business environment change or as new reservoir information indicates the reservoir characterization models on which the current plan is based are inadequate. BDM-Oklahoma and the Department of Energy have implemented a program of reservoir management demonstrations to encourage operators with limited resources and experience to learn, implement, and disperse sound reservoir management techniques through cooperative research and development projects whose objectives are to develop reservoir management plans. In each of the three projects currently underway, careful attention to reservoir management context assures a reservoir characterization approach that is sufficient, but not in excess of what is necessary, to devise and implement an effective reservoir management plan.

Detecting fluid leakage of a reservoir dam based on streaming self-potential measurements

Science.gov (United States)

Song, Seo Young; Kim, Bitnarae; Nam, Myung Jin; Lim, Sung Keun

2015-04-01

Between many reservoir dams for agriculture in suburban area of South Korea, water leakage has been reported several times. The dam under consideration in this study, which is located in Gyeong-buk, in the south-east of the Korean Peninsula, was reported to have a large leakage at the right foot of downstream side of the reservoir dam. For the detection of the leakage, not only geological survey but also geophysical explorations have been made for precision safety diagnosis, since the leakage can lead to dam failure. Geophysical exploration includes both electrical-resistivity and self-potential surveys, while geological surveys water permeability test, standard penetration test, and sampling for undisturbed sample during the course of the drilling investigation. The geophysical explorations were made not only along the top of dam but also transverse the heel of dam. The leakage of water installations can change the known-heterogeneous structure of the dam body but also cause streaming spontaneous (self) potential (SP) anomaly, which can be detected by electrical resistivity and SP measurements, respectively. For the interpretation of streaming SP, we used trial-and-error method by comparing synthetic SP data with field SP data for model update. For the computation, we first invert the resistivity data to obtain the distorted resistivity structure of the dam levee then make three-dimensional electrical-resistivity modeling for the streaming potential distribution of the dam levee. Our simulation algorithm of streaming SP distribution based on the integrated finite difference scheme computes two-dimensional (2D) SP distribution based on the distribution of calculated flow velocities of fluid for a given permeability structure together with physical properties. This permeability is repeatedly updated based on error between synthetic and field SP data, until the synthetic data match the field data. Through this trial-and-error-based SP interpretation, we locate the

Chemical conditions of the Japanese neutral geothermal reservoirs

International Nuclear Information System (INIS)

Chiba, H.

1991-01-01

The aqueous speciation were calculated for fluids of seven Japanese geothermal systems. The aqueous composition as well as CO 2 partial pressure of fluid in neutral pH geothermal reservoir are controlled by silicate, calcite and anhydrite minerals. The chemical composition of neutral pH geothermal reservoir can be predictable if two parameters (e.g. temperature and one of the cation activities) are provided. (author)

Summary review of workshop on movement of fluids in largely impermeable rocks

International Nuclear Information System (INIS)

Witherspoon, P.A.

1977-01-01

As a starting point for the workshop, the following general question was posed, ''What data base, analytical methodology, and technology are necessary to adequately forecast the physical behavior of the subsurface disposal facility.'' The critical consideration was the movement of fluids through fractured rock masses. The first day of the workshop was devoted to general discussions of selected topics. On the second day, the participants were divided into six working groups: (1) definition and characterization of the fracture system; (2) in-situ measurement of fluid flow; (3) effects of perturbations on the flow system; (4) role of numerical modeling; (5) isotopic and geochemical methods; and (6) monitoring programs to verify flow system. The reports prepared by each working group were edited to some extent

DEVELOPMENT OF RESERVOIR CHARACTERIZATION TECHNIQUES AND PRODUCTION MODELS FOR EXPLOITING NATURALLY FRACTURED RESERVOIRS

Energy Technology Data Exchange (ETDEWEB)

Michael L. Wiggins; Raymon L. Brown; Faruk Civan; Richard G. Hughes

2002-12-31

For many years, geoscientists and engineers have undertaken research to characterize naturally fractured reservoirs. Geoscientists have focused on understanding the process of fracturing and the subsequent measurement and description of fracture characteristics. Engineers have concentrated on the fluid flow behavior in the fracture-porous media system and the development of models to predict the hydrocarbon production from these complex systems. This research attempts to integrate these two complementary views to develop a quantitative reservoir characterization methodology and flow performance model for naturally fractured reservoirs. The research has focused on estimating naturally fractured reservoir properties from seismic data, predicting fracture characteristics from well logs, and developing a naturally fractured reservoir simulator. It is important to develop techniques that can be applied to estimate the important parameters in predicting the performance of naturally fractured reservoirs. This project proposes a method to relate seismic properties to the elastic compliance and permeability of the reservoir based upon a sugar cube model. In addition, methods are presented to use conventional well logs to estimate localized fracture information for reservoir characterization purposes. The ability to estimate fracture information from conventional well logs is very important in older wells where data are often limited. Finally, a desktop naturally fractured reservoir simulator has been developed for the purpose of predicting the performance of these complex reservoirs. The simulator incorporates vertical and horizontal wellbore models, methods to handle matrix to fracture fluid transfer, and fracture permeability tensors. This research project has developed methods to characterize and study the performance of naturally fractured reservoirs that integrate geoscience and engineering data. This is an important step in developing exploitation strategies for

Ground movements associated with gas hydrate production

International Nuclear Information System (INIS)

Siriwardane, H.J.; Kutuk, B.

1992-03-01

This report deals with a study directed towards a modeling effort on production related ground movements and subsidence resulting from hydrate dissociation. The goal of this research study was to evaluate whether there could be subsidence related problems that could be an impediment to hydrate production. During the production of gas from a hydrate reservoir, it is expected that porous reservoir matrix becomes more compressible which may cause reservoir compression (compaction) under the influence of overburden weight. The overburden deformations can propagate its influence upwards causing subsidence near the surface where production equipment will be located. In the present study, the reservoir compaction is modeled by using the conventional ''stress equilibrium'' approach. In this approach, the overburden strata move under the influence of body force (i.e. self weight) in response to the ''cavity'' generated by reservoir depletion. The present study is expected to provide a ''lower bound'' solution to the subsidence caused by hydrate reservoir depletion. The reservoir compaction anticipated during hydrate production was modeled by using the finite element method, which is a powerful computer modeling technique. The ground movements at the reservoir roof (i.e. reservoir compression) cause additional stresses and disturbance in the overburden strata. In this study, the reservoir compaction was modeled by using the conventional ''stress equilibrium'' approach. In this approach, the overburden strata move under the influence of body force (i.e. self weight) in response to the ''cavity'' generated by reservoir depletion. The resulting stresses and ground movements were computed by using the finite element method. Based on the parameters used in this investigation, the maximum ground subsidence could vary anywhere from 0.50 to 6.50 inches depending on the overburden depth and the size of the depleted hydrate reservoir

Analysis of nitrogen injection as alternative fluid to steam in heavy oil reservoir; Analise da injecao de nitrogenio como fluido alternativo ao vapor em reservatorio de oleo pesado

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, Marcos Allyson Felipe; Galvao, Edney Rafael Viana Pinheiro; Barillas, Jennys Lourdes; Mata, Wilson da; Dutra Junior, Tarcilio Viana [Universidade Federal do Rio Grande do Norte (UFRN), RN (Brazil)

2012-07-01

Many of hydrocarbon reserves existing in the world are formed by heavy oils (deg API between 10 and 20). Moreover, several heavy oil fields are mature and, thus, offer great challenges for oil industry. Among the thermal methods used to recover these resources, steam flooding has been the main economically viable alternative. Latent heat carried by steam heats the reservoir, reducing oil viscosity and facilitating the production. This method has many variations and has been studied both theoretically and experimentally (in pilot projects and in full field applications). In order to increase oil recovery and reduce steam injection costs, the injection of alternative fluid has been used on three main ways: alternately, co-injected with steam and after steam injection interruption. The main objective of these injection systems is to reduce the amount of heat supplied to the reservoir, using cheaper fluids and maintaining the same oil production levels. In this paper, the use of N{sub 2} as an alternative fluid to the steam was investigated. The analyzed parameters were oil recoveries and net cumulative oil productions. The reservoir simulation model corresponds to an oil reservoir of 100 m x 100 m x 28 m size, on a Cartesian coordinates system (x, y and z directions). It is a semi synthetic model with some reservoir data similar to those found in Potiguar Basin, Brazil. All studied cases were done using the simulator STARS from CMG (Computer Modelling Group, version 2009.10). It was found that N{sub 2} injection after steam injection interruption achieved the highest net cumulative oil compared to others injection system. Moreover, it was observed that N2 as alternative fluid to steam did not present increase on oil recovery. (author)

Systems and methods for multi-fluid geothermal energy systems

Science.gov (United States)

Buscheck, Thomas A.

2017-09-19

A method for extracting geothermal energy from a geothermal reservoir formation. A production well is used to extract brine from the reservoir formation. At least one of nitrogen (N.sub.2) and carbon dioxide (CO.sub.2) may be used to form a supplemental working fluid which may be injected into a supplemental working fluid injection well. The supplemental working fluid may be used to augment a pressure of the reservoir formation, to thus drive a flow of the brine out from the reservoir formation.

The impact of hydraulic flow unit & reservoir quality index on pressure profile and productivity index in multi-segments reservoirs

Directory of Open Access Journals (Sweden)

Salam Al-Rbeawi

2017-12-01

Full Text Available The objective of this paper is studying the impact of the hydraulic flow unit and reservoir quality index (RQI on pressure profile and productivity index of horizontal wells acting in finite reservoirs. Several mathematical models have been developed to investigate this impact. These models have been built based on the pressure distribution in porous media, depleted by a horizontal well, consist of multi hydraulic flow units and different reservoir quality index. The porous media are assumed to be finite rectangular reservoirs having different configurations and the wellbores may have different lengths. Several analytical models describing flow regimes have been derived wherein hydraulic flow units and reservoir quality index have been included in addition to rock and fluid properties. The impact of these two parameters on reservoir performance has also been studied using steady state productivity index.It has been found that both pressure responses and flow regimes are highly affected by the existence of multiple hydraulic flow units in the porous media and the change in reservoir quality index for these units. Positive change in the RQI could lead to positive change in both pressure drop required for reservoir fluids to move towards the wellbore and hence the productivity index.

Development of simulation programs for three dimensional movement of fluid

Energy Technology Data Exchange (ETDEWEB)

Kim, Bok Youn; Kang, Chang Hee; Jo, Young Do; Lim, Sang Taek [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

1996-12-01

It is third project year on `Application of mobile diesel equipment in underground mines` for providing appropriate measures to improve underground working environment contaminated by the diesel exhaust pollutants. For simulating three dimensional movement of fluid in closed spaces like dead-end workings ; a software (3D-Flow) based on computerized fluid dynamics (CFD) has been developed. According to simulations using this software, following results are derived. 1) The heading faces where a diesel equipment is employed should be ventilated even though the extension is as short as 20 meters long. 2) Even there is no ventilation, the gas concentration of the heading face reaches no more than 15 % in ceiling and 5 % in the region where workers are in action approximately. 3) Gases are formed regular horizontal laminar flow when there is no ventilation. 4) In ventilated headings, it is same that the gas concentration of working region is about 30 % of the concentration of ceiling and gases are formed irregular turbulent flow. (author). 2 tabs., 15 figs.

Update on Production Chemistry of the Roosevelt Hot Springs Reservoir

Energy Technology Data Exchange (ETDEWEB)

Simmons, Stuart; Kirby, Stefan; Allis, Rick; Moore, Joe; Fischer, Tobias

2018-02-12

Analyses of production fluids from the Roosevelt Hot Springs reservoir were acquired from well sampling campaigns in 2015 and 2016. The resulting data have been recalculated to reservoir conditions by correcting for effects of steam loss, and the values are compared to legacy data from earlier reports to quantify changes with time in response to fluid production. The reservoir composition is similar to that at the start of reservoir exploitation, having near neutral pH, total dissolved solids of 7000-10,000 mg/kg, and ionic ratios of Cl/HCO3 ~50-100, Cl/SO4 ~50-100, and Na/K ~4-5. Cation, gas and silica geothermometers indicate a range of equilibration temperatures between 240 and 300 °C, but quartz-silica values are most closely consistent with measured reservoir temperatures and well enthalpies. The largest change in fluid composition is observed in well 54-3. The fluid has evolved from being fed by a single phase liquid to a twophase mixture of steam and liquid due to pressure draw down. The fluid also shows a 25% increase in reservoir chloride and a ~20° C decrement of cooling related to mixing with injected brine. The other production wells also show increase in chloride and decrease in temperature, but these changes diminish in magnitude with distance from injection well 14-2. Stable isotope compositions indicate that the reservoir water is largely meteoric in origin, having been modified by hydrothermal waterrock interaction. The water has also become progressively enriched in isotopic values in response to steam loss and mixing of injectate. N2-Ar-He and helium isotope ratios indicate a deep magmatic source region that probably supplies the heat for the hydrothermal system, consistent with recent Quaternary volcanism in the Mineral Mountains.

Hydrochemical and isotope study to trace the movement of pollutants from the Akuosu - Sukobri tributary into the Owabi reservoir

International Nuclear Information System (INIS)

Frimpong, E.O.

2011-01-01

Surface water and sediment samples of the Akuosu - Sukobri tributary were analyzed to asses the movement of heavy metal pollution into the Owabi reservoir. Whilst the Akuosu - Sukobri tributary is acidic, the Owabi reservoir is basic. The concentration of Na, K, Mg, Ca, Cl, SO 4 , As, Mn, Cr, Cu, Zn are all below world normal averages in the water but they exceed these world averages in the sediments. HEI, HPI and C d show that the part of the Akuosu - Sukobri tributary at Suame Magazine, Anomagye Township and Bohyen are polluted whilst pollution is minimal at the part of the tributary in the Owabi Forest Reserve as well as the Owabi reservoir. Sediment pollution assessment was carried out using enrichment factor (EF), geoaccumulation index (I geo ) and pollution load index (PLI). EF shows that the sediments are enriched in the heavy metals. The I geo values revealed that the sediments are significantly accumulated with Pb, Cu and Cr whilst the PLI suggest that the sediments are moderately polluted. An integrated approach of pollution indices, principal component analysis (PCA) and cluster analysis (CA) was employed to evaluate the intensity and sources of pollution in the tributary and the reservoir. This showed that the major ions mainly originated from domestic waste whilst the heavy metals come from the various anthropogenic activities along the tributary especially the Suame Magazine part of the Akuosu - Sukobri tributary. Isotope analysis of the water showed that the water is mainly of meteoric origin with very little enrichment probably due to evaporation and mixing along the way before the Akuoso-Sukobri tributary joins the Owabi reservoir. (au)

An Embedded 3D Fracture Modeling Approach for Simulating Fracture-Dominated Fluid Flow and Heat Transfer in Geothermal Reservoirs

Energy Technology Data Exchange (ETDEWEB)

Johnston, Henry [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wang, Cong [Colorado School of Mines; Winterfeld, Philip [Colorado School of Mines; Wu, Yu-Shu [Colorado School of Mines

2018-02-14

An efficient modeling approach is described for incorporating arbitrary 3D, discrete fractures, such as hydraulic fractures or faults, into modeling fracture-dominated fluid flow and heat transfer in fractured geothermal reservoirs. This technique allows 3D discrete fractures to be discretized independently from surrounding rock volume and inserted explicitly into a primary fracture/matrix grid, generated without including 3D discrete fractures in prior. An effective computational algorithm is developed to discretize these 3D discrete fractures and construct local connections between 3D fractures and fracture/matrix grid blocks of representing the surrounding rock volume. The constructed gridding information on 3D fractures is then added to the primary grid. This embedded fracture modeling approach can be directly implemented into a developed geothermal reservoir simulator via the integral finite difference (IFD) method or with TOUGH2 technology This embedded fracture modeling approach is very promising and computationally efficient to handle realistic 3D discrete fractures with complicated geometries, connections, and spatial distributions. Compared with other fracture modeling approaches, it avoids cumbersome 3D unstructured, local refining procedures, and increases computational efficiency by simplifying Jacobian matrix size and sparsity, while keeps sufficient accuracy. Several numeral simulations are present to demonstrate the utility and robustness of the proposed technique. Our numerical experiments show that this approach captures all the key patterns about fluid flow and heat transfer dominated by fractures in these cases. Thus, this approach is readily available to simulation of fractured geothermal reservoirs with both artificial and natural fractures.

Pressure and fluid saturation prediction in a multicomponent reservoir, using combined seismic and electromagnetic imaging

International Nuclear Information System (INIS)

Hoversten, G.M.; Gritto, Roland; Washbourne, John; Daley, Tom

2002-01-01

This paper presents a method for combining seismic and electromagnetic measurements to predict changes in water saturation, pressure, and CO 2 gas/oil ratio in a reservoir undergoing CO 2 flood. Crosswell seismic and electromagnetic data sets taken before and during CO 2 flooding of an oil reservoir are inverted to produce crosswell images of the change in compressional velocity, shear velocity, and electrical conductivity during a CO 2 injection pilot study. A rock properties model is developed using measured log porosity, fluid saturations, pressure, temperature, bulk density, sonic velocity, and electrical conductivity. The parameters of the rock properties model are found by an L1-norm simplex minimization of predicted and observed differences in compressional velocity and density. A separate minimization, using Archie's law, provides parameters for modeling the relations between water saturation, porosity, and the electrical conductivity. The rock-properties model is used to generate relationships between changes in geophysical parameters and changes in reservoir parameters. Electrical conductivity changes are directly mapped to changes in water saturation; estimated changes in water saturation are used along with the observed changes in shear wave velocity to predict changes in reservoir pressure. The estimation of the spatial extent and amount of CO 2 relies on first removing the effects of the water saturation and pressure changes from the observed compressional velocity changes, producing a residual compressional velocity change. This velocity change is then interpreted in terms of increases in the CO 2 /oil ratio. Resulting images of the CO 2 /oil ratio show CO 2 -rich zones that are well correlated to the location of injection perforations, with the size of these zones also correlating to the amount of injected CO 2 . The images produced by this process are better correlated to the location and amount of injected CO 2 than are any of the individual

Penerapan Dinamika Fluida dalam Perhitungan Kecepatan Aliran dan Perolehan Minyak di Reservoir

Directory of Open Access Journals (Sweden)

Dwi Listriana Kusumastuti

2014-12-01

Full Text Available Water, oil and gas inside the earth are stored in the pores of the reservoir rock. In the world of petroleum industry, calculation of volume of the oil that can be recovered from the reservoir is something important to do. This calculation involves the calculation of the velocity of fluid flow by utilizing the principles and formulas provided by the Fluid Dynamics. The formula is usually applied to the fluid flow passing through a well defined control volume, for example: cylinder, curved pipe, straight pipes with different diameters at the input and output, and so forth. However, because of reservoir rock, as the fluid flow medium, has a wide variety of possible forms of the control volumes, hence, calculation of the velocity of the fluid flow is becoming difficult as it would involve calculations of fluid flow velocity for each control volume. This difficulties is mainly caused by the fact that these control volumes, that existed in the rock, cannot be well defined. This paper will describe a method for calculating this fluid flow velocity of the control volume, which consists of a combination of laboratory measurements and the use of some theories in the Fluid Dynamics. This method has been proofed can be used for calculating fluid flow velocity as well as oil recovery in reservoir rocks, with fairly good accuration.

Lattice gas automaton scheme with stochastic particle movement for a rotated fluid flow

International Nuclear Information System (INIS)

Ishiguro, Misako

2002-01-01

Lattice gas automaton (LGA) models developed so far are just for Cartesian geometries, and no direct approach to rotated fluid flows is found. In this paper, LGA method is applied to model a two-dimensional rotated flow. Several problems specific to the rotated flow are to be solved: hexagonal lattice geometry to effectively identify the neighbors, boundary condition for irregular walls, multi-speed scheme to represent angular-oriented fluid velocity υ θ ≅γω, shape of macroscopic domain for statistics, formula to obtain macroscopic quantities such as density and mean fluid velocities, application method of Fermi-Dirac function to the initial particle arrangement. For this purpose, FHP-I type hexagonal lattice model is revised and a new LGA model with stochastic particle movement is proposed. The results of the trial calculation are shown. It is also investigated whether or not the underlying microscopic Boolean equations newly introduced leads to Navier-Stokes equation. (author)

Behaviour of gas production from type 3 hydrate reservoirs

Energy Technology Data Exchange (ETDEWEB)

Pooladi-Darvish, M. [Calgary Univ., AB (Canada). Dept. of Chemical and Petroleum Engineering]|[Fekete Associates Inc., Calgary, AB (Canada); Zatsepina, O. [Calgary Univ., AB (Canada). Dept. of Chemical and Petroleum Engineering; Hong, H. [Fekete Associates Inc., Calgary, AB (Canada)

2008-07-01

The possible role of gas hydrates as a potential energy resource was discussed with particular reference to methods for estimating the rate of gas production from hydrate reservoirs under different operating conditions. This paper presented several numerical simulations studies of gas production from type 3 hydrate reservoirs in 1-D and 2-D geometries. Type 3 reservoirs include gas production from hydrate-reservoirs that lie totally within the hydrate stability zone and are sandwiched by impermeable layers on top and bottom. The purpose of this study was to better understand hydrate decomposition by depressurization. The study questioned whether 1-D modeling of type 3 hydrate reservoirs is a reasonable approximation. It also determined whether gas rate increases or decreases with time. The important reservoir characteristics for determining the rate of gas production were identified. Last, the study determined how competition between fluid and heat flow affects hydrate decomposition. This paper also described the relation and interaction between the heat and fluid flow mechanisms in depressurization of type 3 hydrate reservoirs. All results of 1-D and 2-D numerical simulation and analyses were generated using the STARS simulator. It was shown that the rate of gas production depends on the initial pressure/temperature conditions and permeability of the hydrate bearing formation. A high peak rate may be achieved under favourable conditions, but this peak rate is obtained after an initial period where the rate of gas production increases with time. The heat transfer in the direction perpendicular to the direction of fluid flow is significant, requiring 2D modeling. The hydraulic diffusivity is low because of the low permeability of hydrate-bearing formations. This could result in competition between heat and fluid flow, thereby influencing the behaviour of decomposition. 6 refs., 3 tabs., 12 figs.

Numerical Modeling and Investigation of Fluid-Driven Fracture Propagation in Reservoirs Based on a Modified Fluid-Mechanically Coupled Model in Two-Dimensional Particle Flow Code

Directory of Open Access Journals (Sweden)

Jian Zhou

2016-09-01

Full Text Available Hydraulic fracturing is a useful tool for enhancing rock mass permeability for shale gas development, enhanced geothermal systems, and geological carbon sequestration by the high-pressure injection of a fracturing fluid into tight reservoir rocks. Although significant advances have been made in hydraulic fracturing theory, experiments, and numerical modeling, when it comes to the complexity of geological conditions knowledge is still limited. Mechanisms of fluid injection-induced fracture initiation and propagation should be better understood to take full advantage of hydraulic fracturing. This paper presents the development and application of discrete particle modeling based on two-dimensional particle flow code (PFC2D. Firstly, it is shown that the modeled value of the breakdown pressure for the hydraulic fracturing process is approximately equal to analytically calculated values under varied in situ stress conditions. Furthermore, a series of simulations for hydraulic fracturing in competent rock was performed to examine the influence of the in situ stress ratio, fluid injection rate, and fluid viscosity on the borehole pressure history, the geometry of hydraulic fractures, and the pore-pressure field, respectively. It was found that the hydraulic fractures in an isotropic medium always propagate parallel to the orientation of the maximum principal stress. When a high fluid injection rate is used, higher breakdown pressure is needed for fracture propagation and complex geometries of fractures can develop. When a low viscosity fluid is used, fluid can more easily penetrate from the borehole into the surrounding rock, which causes a reduction of the effective stress and leads to a lower breakdown pressure. Moreover, the geometry of the fractures is not particularly sensitive to the fluid viscosity in the approximate isotropic model.

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.

Major hydrogeochemical processes in the two reservoirs of the Yangbajing geothermal field, Tibet, China

Science.gov (United States)

Guo, Qinghai; Wang, Yanxin; Liu, Wei

2007-10-01

The Yangbajing geothermal field with the highest reservoir temperature in China is located about 90 km northwest to Lhasa City, capital of Tibet, where high temperature geothermal fluids occur both in shallow and deep reservoirs. The geophysical survey by the INDEPTH (International Deep Profiling of Tibet and the Himalayas) project group proved the existence of magmatic heat source at Yangbajing. In the study area, the hydrochemistry of cold surface waters and groundwaters and that of thermal groundwaters from both reservoirs are distinctively different. However, analysis of the relationship between enthalpy values and Cl concentrations of cold groundwaters and geothermal fluids indicates that the geothermal fluids from the shallow reservoir were formed as a result of mixing of cold groundwaters with geothermal fluids from the deep reservoir. In other words, the geothermal fluids from the deep reservoir flowed upwards into the shallow reservoir where it was diluted by the shallow cold groundwaters to form the shallow geothermal fluids with much lower temperature. A binary mixing model with two endmembers (the cold groundwaters and the deep geothermal fluids) was proposed and the mixing ratios for the geothermal fluid from each shallow well were estimated. Using the mixing ratios, the concentrations of some constituents in shallow geothermal fluids, such as As, B, SiO 2, SO 42- and F, were calculated and their differences with the actual concentrations were estimated. The results show that the differences between estimated and actual concentrations of As and B are small (the average absolute values being only 1.9% and 7.9%, respectively), whereas those of SiO 2, SO 42- and F are much bigger, indicating that other hydrogeochemical processes are responsible for the concentrations of these constituents. It is postulated that SiO 2 precipitation due to water temperature decrease, H 2S oxidation and ion exchange between OH - in geothermal waters and exchangeable F - in

A nonlinear model for fluid flow in a multiple-zone composite reservoir including the quadratic gradient term

International Nuclear Information System (INIS)

Wang, Xiao-Lu; Fan, Xiang-Yu; Nie, Ren-Shi; Huang, Quan-Hua; He, Yong-Ming

2013-01-01

Based on material balance and Darcy's law, the governing equation with the quadratic pressure gradient term was deduced. Then the nonlinear model for fluid flow in a multiple-zone composite reservoir including the quadratic gradient term was established and solved using a Laplace transform. A series of standard log–log type curves of 1-zone (homogeneous), 2-zone and 3-zone reservoirs were plotted and nonlinear flow characteristics were analysed. The type curves governed by the coefficient of the quadratic gradient term (β) gradually deviate from those of a linear model with time elapsing. Qualitative and quantitative analyses were implemented to compare the solutions of the linear and nonlinear models. The results showed that differences of pressure transients between the linear and nonlinear models increase with elapsed time and β. At the end, a successful application of the theoretical model data against the field data shows that the nonlinear model will be a good tool to evaluate formation parameters more accurately. (paper)

On the Versatility of Rheoreversible, Stimuli-responsive Hydraulic-Fracturing Fluids for Enhanced Geothermal Systems: Effect of Reservoir pH

Energy Technology Data Exchange (ETDEWEB)

Fernandez, Carlos A.; Shao, Hongbo; Bonneville, Alain; Varga, Tamas; Zhong, Lirong

2016-04-25

Abstract The primary challenge for the feasibility of enhanced geothermal systems (EGS) is to cost-effectively create high-permeability reservoirs inside deep crystalline bedrock. Although fracturing fluids are commonly used for oil/gas, standard fracturing methods are not developed or proven for EGS temperatures and pressures. Furthermore, the environmental impacts of currently used fracturing methods are only recently being determined. These authors recently reported an environmentally benign, CO2-activated, rheoreversible fracturing fluid that enhances permeability through fracturing due to in situ volume expansion and gel formation. The potential of this novel fracturing fluid is evaluated in this work towards its application at geothermal sites under different pH conditions. Laboratory-scale fracturing experiments using Coso Geothermal rock cores under different pH environments were performed followed by X-ray microtomography characterization. The results demonstrate that CO2-reactive aqueous solutions of environmentally amenable polyallylamine (PAA) consistently and reproducibly creates/propagates fracture networks through highly impermeable crystalline rock from Coso EGS sites at considerably lower effective stress as compared to conventional fracturing fluids. In addition, permeability was significantly enhanced in a wide range of formation-water pH values. This effective, and environmentally-friendly fracturing fluid technology represents a potential alternative to conventional fracturing fluids.

Multi Data Reservoir History Matching using the Ensemble Kalman Filter

KAUST Repository

Katterbauer, Klemens

2015-05-01

Reservoir history matching is becoming increasingly important with the growing demand for higher quality formation characterization and forecasting and the increased complexity and expenses for modern hydrocarbon exploration projects. History matching has long been dominated by adjusting reservoir parameters based solely on well data whose spatial sparse sampling has been a challenge for characterizing the flow properties in areas away from the wells. Geophysical data are widely collected nowadays for reservoir monitoring purposes, but has not yet been fully integrated into history matching and forecasting fluid flow. In this thesis, I present a pioneering approach towards incorporating different time-lapse geophysical data together for enhancing reservoir history matching and uncertainty quantification. The thesis provides several approaches to efficiently integrate multiple geophysical data, analyze the sensitivity of the history matches to observation noise, and examine the framework’s performance in several settings, such as the Norne field in Norway. The results demonstrate the significant improvements in reservoir forecasting and characterization and the synergy effects encountered between the different geophysical data. In particular, the joint use of electromagnetic and seismic data improves the accuracy of forecasting fluid properties, and the usage of electromagnetic data has led to considerably better estimates of hydrocarbon fluid components. For volatile oil and gas reservoirs the joint integration of gravimetric and InSAR data has shown to be beneficial in detecting the influx of water and thereby improving the recovery rate. Summarizing, this thesis makes an important contribution towards integrated reservoir management and multiphysics integration for reservoir history matching.

Physical Aspects in Upscaling of Fractured Reservoirs and Improved Oil Recovery Prediction

NARCIS (Netherlands)

Salimi, H.

2010-01-01

This thesis is concerned with upscaled models for waterflooded naturally fractured reservoirs (NFRs). Naturally fractured petroleum reservoirs provide over 20% of the world’s oil reserves and production. From the fluid-flow point of view, a fractured reservoir is defined as a reservoir in which a

Hydrogeologic controls on induced seismicity in crystalline basement rocks due to fluid injection into basal reservoirs.

Science.gov (United States)

Zhang, Yipeng; Person, Mark; Rupp, John; Ellett, Kevin; Celia, Michael A; Gable, Carl W; Bowen, Brenda; Evans, James; Bandilla, Karl; Mozley, Peter; Dewers, Thomas; Elliot, Thomas

2013-01-01

A series of Mb 3.8-5.5 induced seismic events in the midcontinent region, United States, resulted from injection of fluid either into a basal sedimentary reservoir with no underlying confining unit or directly into the underlying crystalline basement complex. The earthquakes probably occurred along faults that were likely critically stressed within the crystalline basement. These faults were located at a considerable distance (up to 10 km) from the injection wells and head increases at the hypocenters were likely relatively small (∼70-150 m). We present a suite of simulations that use a simple hydrogeologic-geomechanical model to assess what hydrogeologic conditions promote or deter induced seismic events within the crystalline basement across the midcontinent. The presence of a confining unit beneath the injection reservoir horizon had the single largest effect in preventing induced seismicity within the underlying crystalline basement. For a crystalline basement having a permeability of 2 × 10(-17)  m(2) and specific storage coefficient of 10(-7) /m, injection at a rate of 5455 m(3) /d into the basal aquifer with no underlying basal seal over 10 years resulted in probable brittle failure to depths of about 0.6 km below the injection reservoir. Including a permeable (kz  = 10(-13)  m(2) ) Precambrian normal fault, located 20 m from the injection well, increased the depth of the failure region below the reservoir to 3 km. For a large permeability contrast between a Precambrian thrust fault (10(-12)  m(2) ) and the surrounding crystalline basement (10(-18)  m(2) ), the failure region can extend laterally 10 km away from the injection well. © 2013, National Ground Water Association.

Peak Discharge, Flood Profile, Flood Inundation, and Debris Movement Accompanying the Failure of the Upper Reservoir at the Taum Sauk Pump Storage Facility near Lesterville, Missouri

Science.gov (United States)

Rydlund, Jr., Paul H.

2006-01-01

The Taum Sauk pump-storage hydroelectric power plant located in Reynolds County, Missouri, uses turbines that operate as pumps and hydraulic head generated by discharging water from an upper to a lower reservoir to produce electricity. A 55-acre upper reservoir with a 1.5- billion gallon capacity was built on top of Proffit Mountain, approximately 760 feet above the floodplain of the East Fork Black River. At approximately 5:16 am on December 14, 2005, a 680-foot wide section of the upper reservoir embankment failed suddenly, sending water rushing down the western side of Proffit Mountain and emptying into the floodplain of East Fork Black River. Flood waters from the upper reservoir flowed downstream through Johnson's Shut-Ins State Park and into the lower reservoir of the East Fork Black River. Floods such as this present unique challenges and opportunities to analyze and document peak-flow characteristics, flood profiles, inundation extents, and debris movement. On December 16, 2005, Light Detection and Ranging (LiDAR) data were collected and used to support hydraulic analyses, forensic failure analyses, damage extent, and mitigation of future disasters. To evaluate the impact of sedimentation in the lower reservoir, a bathymetric survey conducted on December 22 and 23, 2005, was compared to a previous bathymetric survey conducted in April, 2005. Survey results indicated the maximum reservoir capacity difference of 147 acre-feet existed at a pool elevation of 730 feet. Peak discharge estimates of 289,000 cubic feet per second along Proffit Mountain and 95,000 cubic feet per second along the East Fork Black River were determined through indirect measurement techniques. The magnitude of the embankment failure flood along the East Fork Black River was approximately 4 times greater than the 100-year flood frequency estimate of 21,900 cubic feet per second, and approximately 3 times greater than the 500-year flood frequency estimate of 30,500 cubic feet per second

Appraisal of transport and deformation in shale reservoirs using natural noble gas tracers

Energy Technology Data Exchange (ETDEWEB)

Heath, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kuhlman, Kristopher L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Robinson, David G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bauer, Stephen J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gardner, William Payton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Univ. of Montana, Missoula, MT (United States)

2015-09-01

This report presents efforts to develop the use of in situ naturally-occurring noble gas tracers to evaluate transport mechanisms and deformation in shale hydrocarbon reservoirs. Noble gases are promising as shale reservoir diagnostic tools due to their sensitivity of transport to: shale pore structure; phase partitioning between groundwater, liquid, and gaseous hydrocarbons; and deformation from hydraulic fracturing. Approximately 1.5-year time-series of wellhead fluid samples were collected from two hydraulically-fractured wells. The noble gas compositions and isotopes suggest a strong signature of atmospheric contribution to the noble gases that mix with deep, old reservoir fluids. Complex mixing and transport of fracturing fluid and reservoir fluids occurs during production. Real-time laboratory measurements were performed on triaxially-deforming shale samples to link deformation behavior, transport, and gas tracer signatures. Finally, we present improved methods for production forecasts that borrow statistical strength from production data of nearby wells to reduce uncertainty in the forecasts.

Thermodynamic state updated of the volcanic caldera and geothermal reservoir of Los Humeros, Puebla, Mexico

Energy Technology Data Exchange (ETDEWEB)

Martinez Reyes, Jose; Gonzalez Partida, Eduardo; Jorge, A [Centro de Geociencias, Universidad National Autonoma de Mexico Campo de Juriquilla, Qro., Mexico, apartado postal 76230 (Mexico); Perez, Renee J [Department of Chemical and Petroleum Engineering, University of Calgary, 500 University Drive, Calgary Alberta, T2N 1N4 (Canada); Tinoco, Michel

2008-10-01

Based on information of enthalpies of the fluids of wells from the geothermal reservoir of Los Humeros, Puebla, Mexico, we determined the thermodynamic conditions of the reservoir comparing the values of enthalpies of the fluids of discharge of the wells with the values published in the literature for different thermodynamic state of fluids.

Hydrocarbon accumulation in deep fluid modified carbonate rock in the Tarim Basin

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

The activities of deep fluid are regionalized in the Tarim Basin. By analyzing the REE in core samples and crude oil, carbon isotope of carbon dioxide and inclusion temperature measurement in the west of the Tazhong Uplift in the western Tarim Basin, all the evidence confirms the existence of deep fluid. The deep fluid below the basin floor moved up into the basin through discordogenic fauit and volcanicity to cause corrosion and metaaomatosis of carbonate rock by exchange of matter and energy. The pore structure and permeability of the carbonate reservoirs were improved, making the carbonate reservoirs an excellent type of deeply buried modification. The fluorite ore belts discovered along the large fault and the volcanic area in the west of the Tazhong Uplift are the outcome of deep fluid action. Such carbonate reservoirs are the main type of reservoirs in the Tazhong 45 oilfield. The carbonate reservoirs in well YM 7 are improved obviously by thermal fluid dolomitization. The origin and territory of deep fluid are associated with the discordogenic fault and volcanicity in the basin. The discordogenic fault and volcanic area may be the pointer of looking for the deep fluid modified reservoirs. The primary characteristics of hydrocarbon accumulation in deep fluid reconstructed carbonate rock are summarized as accumulation near the large fault and volcano passage, late-period hydrocarbon accumulation after volcanic activity, and subtle trap reservoirs controlled by lithology.

Gas geochemistry for the Los Azufres (Michoacán geothermal reservoir, México

Directory of Open Access Journals (Sweden)

N. Segovia

2005-06-01

Full Text Available Gas data of the Los Azufres geothermal field were analyzed using a method based on equilibrium of the Fischer- Tropsch (FT reaction: CH4 + 2H2O = 4H2 +CO2 and on the combined pyrite-hematite-magnetite (HSH2 reactions: 5/4 H2 +3/2 FeS2 +3/4 Fe2O3 + 7/4 H2O = 3 H2S +Fe3O4 in order to estimate reservoir temperature and excess steam. The solution of equilibrium equations produces a grid (FT-HSH2. This method is suitable for reservoirs with relatively high H2S but low H2 and NH3 concentrations in the fluid as is the case of the Los Azufres well discharges. Reservoir temperature and reservoir excess steam values were estimated for initial and present conditions in representative wells of the field to study the evolution of fluids, because of exploitation and waste fluids reinjection. This method was very useful in estimating reservoir temperatures in vapor wells, while in two-phase wells it was found that as the well produces a smaller fraction of water, the reservoir temperature estimation agrees qualitatively with results from cationic or silica geothermometers. For liquid-dominated wells the reservoir temperature estimations agree with temperatures obtained from the well simulator WELFLO. This indicates that FT-HSH2 results provide the temperature of the fluid entering the well where the last equilibrium occurs. Results show a decrease in reservoir temperatures in the southern zone of the field where intensive reinjection takes place. With exploitation, it was also noted that the deep liquid phase in the reservoir is changing to two-phase increasing the reservoir steam fraction and the non-condensable gases in well discharges.

Understanding and Mitigating Reservoir Compaction: an Experimental Study on Sand Aggregates

Science.gov (United States)

Schimmel, M.; Hangx, S.; Spiers, C. J.

2016-12-01

Fossil fuels continue to provide a source for energy, fuels for transport and chemicals for everyday items. However, adverse effects of decades of hydrocarbons production are increasingly impacting society and the environment. Production-driven reduction in reservoir pore pressure leads to a poro-elastic response of the reservoir, and in many occasions to time-dependent compaction (creep) of the reservoir. In turn, reservoir compaction may lead to surface subsidence and could potentially result in induced (micro)seismicity. To predict and mitigate the impact of fluid extraction, we need to understand production-driven reservoir compaction in highly porous siliciclastic rocks and explore potential mitigation strategies, for example, by using compaction-inhibiting injection fluids. As a first step, we investigate the effect of chemical environment on the compaction behaviour of sand aggregates, comparable to poorly consolidated, highly porous sandstones. The sand samples consist of loose aggregates of Beaujean quartz sand, sieved into a grainsize fraction of 180-212 µm. Uniaxial compaction experiments are performed at an axial stress of 35 MPa and temperature of 80°C, mimicking conditions of reservoirs buried at three kilometres depth. The chemical environment during creep is either vacuum-dry or CO2-dry, or fluid-saturated, with fluids consisting of distilled water, acid solution (CO2-saturated water), alkaline solution (pH 9), aluminium solution (pH 3) and solution with surfactants (i.e., AMP). Preliminary results show that compaction of quartz sand aggregates is promoted in a wet environment compared to a dry environment. It is inferred that deformation is controlled by subcritical crack growth when dry and stress corrosion cracking when wet, both resulting in grain failure and subsequent grain rearrangement. Fluids inhibiting these processes, have the potential to inhibit aggregate compaction.

Performance analysis for an irreversible variable temperature heat reservoir closed intercooled regenerated Brayton cycle

International Nuclear Information System (INIS)

Wang Wenhua; Chen Lingen; Sun Fengrui; Wu Chih

2003-01-01

In this paper, the theory of finite time thermodynamics is used in the performance analysis of an irreversible closed intercooled regenerated Brayton cycle coupled to variable temperature heat reservoirs. The analytical formulae for dimensionless power and efficiency, as functions of the total pressure ratio, the intercooling pressure ratio, the component (regenerator, intercooler, hot and cold side heat exchangers) effectivenesses, the compressor and turbine efficiencies and the thermal capacity rates of the working fluid and the heat reservoirs, the pressure recovery coefficients, the heat reservoir inlet temperature ratio, and the cooling fluid in the intercooler and the cold side heat reservoir inlet temperature ratio, are derived. The intercooling pressure ratio is optimized for optimal power and optimal efficiency, respectively. The effects of component (regenerator, intercooler and hot and cold side heat exchangers) effectivenesses, the compressor and turbine efficiencies, the pressure recovery coefficients, the heat reservoir inlet temperature ratio and the cooling fluid in the intercooler and the cold side heat reservoir inlet temperature ratio on optimal power and its corresponding intercooling pressure ratio, as well as optimal efficiency and its corresponding intercooling pressure ratio are analyzed by detailed numerical examples. When the heat transfers between the working fluid and the heat reservoirs are executed ideally, the pressure drop losses are small enough to be neglected and the thermal capacity rates of the heat reservoirs are infinite, the results of this paper replicate those obtained in recent literature

Application of MRIL-WD (Magnetic Resonance Imaging Logging While Drilling) for irreducible water saturation, total reservoir, free-fluid, bound-fluid porosity measurements and its value for the petrophysical analysis of RT/RM data from the Shah Deniz well

Science.gov (United States)

Amirov, Elnur

2016-04-01

Sperry-Sun (Sperry Drilling Services) is the leader in MWD/LWD reliability, has developed the industry's first LWD NMR/MRIL-WD (nuclear magnetic resonance) tool. The MRIL-WD (magnetic resonance imaging logging-while-drilling) service directly measures the T1 component of hydrogen in subsurface rock units while drilling to obtain total reservoir porosity and to dissect the observed total porosity into its respective components of free fluid and bound fluid porosity. These T1 data are used to secure accurate total, free-fluid, capillary-bound water, and clay-bound water porosity of the reservoir sections which can be drilled in the several Runs. Over the last decade, results from Magnetic Resonance Imaging logs (NMR) have added significant value to petrophysical analysis and understanding by providing total, free-fluid and bound-fluid porosities, combined with fluid typing capabilities. With MRIL-WD very valuable Real-Time or Recorded Memory data/information is now available during or shortly after the drilling operation (formation properties measurement can be taken right after a drill bit penetration), while trip in and trip out as well. A key point in utilizing MRIL in an LWD environment is motion-tolerant measurements. Recent MRIL-WD logging runs from the Shah Deniz wells located in the Khazarian-Caspian Sea of the Azerbaijan Republic helped to delineate and assess hydrocarbon bearing zones. Acquired results demonstrate how MRIL data can be acquired while-drilling and provide reliable/high quality measurements. Magnetic Resonance Imaging logs at some developments wells have become a cornerstone in formation evaluation and petrophysical understanding. By providing total, free-fluid, and bound-fluid porosities together with fluid typing, MRIL results have significantly added to the assessment of reservoirs. In order to reduce NPT (Non-Productive Time) and save the rig operations time, there is always the desire to obtain logging results as soon as possible

Thermodynamic evolution of the Los Azufres, Mexico, geothermal reservoir from 1982 to 2002

Energy Technology Data Exchange (ETDEWEB)

Arellano, Victor Manuel; Barragan, Rosa Maria [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Reforma 113, Col. Palmira, 62490 Cuernavaca, Morelos (Mexico); Torres, Marco Antonio [Comision Federal de Electricidad, Residencia Los Azufres, Campamento Agua Fria, Los Azufres, Michoacan (Mexico)

2005-10-01

An investigation has been made of the response of the Los Azufres geothermal reservoir to 20 years of development, beginning in 1982. The simulator WELFLO was used to characterize the thermodynamic conditions of the reservoir fluids. The first response to exploitation consisted of a decrease in pressure and an increase in enthalpy. Small decreases in reservoir pressure associated with large increases in fluid enthalpy characterize the long-term response in the northern production area. In the southern production area, long-term changes include decreases in pressure and mass flow rate, increases in steam production and, in wells affected by injection, increases in both pressure and total mass flow rate. These changes reflect the effects of boiling, cooling and fluid mixing, processes resulting from large-scale fluid production. (author)

Offshore Antarctic Peninsula Gas Hydrate Reservoir Characterization by Geophysical Data Analysis

Directory of Open Access Journals (Sweden)

Michela Giustiniani

2010-12-01

Full Text Available A gas hydrate reservoir, identified by the presence of the bottom simulating reflector, is located offshore of the Antarctic Peninsula. The analysis of geophysical dataset acquired during three geophysical cruises allowed us to characterize this reservoir. 2D velocity fields were obtained by using the output of the pre-stack depth migration iteratively. Gas hydrate amount was estimated by seismic velocity, using the modified Biot-Geerstma-Smit theory. The total volume of gas hydrate estimated, in an area of about 600 km2, is in a range of 16 × 109–20 × 109 m3. Assuming that 1 m3 of gas hydrate corresponds to 140 m3 of free gas in standard conditions, the reservoir could contain a total volume that ranges from 1.68 to 2.8 × 1012 m3 of free gas. The interpretation of the pre-stack depth migrated sections and the high resolution morpho-bathymetry image allowed us to define a structural model of the area. Two main fault systems, characterized by left transtensive and compressive movement, are recognized, which interact with a minor transtensive fault system. The regional geothermal gradient (about 37.5 °C/km, increasing close to a mud volcano likely due to fluid-upwelling, was estimated through the depth of the bottom simulating reflector by seismic data.

Method for inverting reflection trace data from 3-D and 4-D seismic surveys and identifying subsurface fluid and pathways in and among hydrocarbon reservoirs based on impedance models

Science.gov (United States)

He, W.; Anderson, R.N.

1998-08-25

A method is disclosed for inverting 3-D seismic reflection data obtained from seismic surveys to derive impedance models for a subsurface region, and for inversion of multiple 3-D seismic surveys (i.e., 4-D seismic surveys) of the same subsurface volume, separated in time to allow for dynamic fluid migration, such that small scale structure and regions of fluid and dynamic fluid flow within the subsurface volume being studied can be identified. The method allows for the mapping and quantification of available hydrocarbons within a reservoir and is thus useful for hydrocarbon prospecting and reservoir management. An iterative seismic inversion scheme constrained by actual well log data which uses a time/depth dependent seismic source function is employed to derive impedance models from 3-D and 4-D seismic datasets. The impedance values can be region grown to better isolate the low impedance hydrocarbon bearing regions. Impedance data derived from multiple 3-D seismic surveys of the same volume can be compared to identify regions of dynamic evolution and bypassed pay. Effective Oil Saturation or net oil thickness can also be derived from the impedance data and used for quantitative assessment of prospective drilling targets and reservoir management. 20 figs.

Modeling reservoir geomechanics using discrete element method : Application to reservoir monitoring

Energy Technology Data Exchange (ETDEWEB)

Alassi, Haitham Tayseer

2008-09-15

Understanding reservoir geomechanical behavior is becoming more and more important for the petroleum industry. Reservoir compaction, which may result in surface subsidence and fault reactivation, occurs during reservoir depletion. Stress changes and possible fracture development inside and outside a depleting reservoir can be monitored using time-lapse (so-called '4D') seismic and/or passive seismic, and this can give valuable information about the conditions of a given reservoir during production. In this study we will focus on using the (particle-based) Discrete Element Method (DEM) to model reservoir geomechanical behavior during depletion and fluid injection. We show in this study that DEM can be used in modeling reservoir geomechanical behavior by comparing results obtained from DEM to those obtained from analytical solutions. The match of the displacement field between DEM and the analytical solution is good, however there is mismatch of the stress field which is related to the way stress is measured in DEM. A good match is however obtained by measuring the stress field carefully. We also use DEM to model reservoir geomechanical behavior beyond the elasticity limit where fractures can develop and faults can reactivate. A general technique has been developed to relate DEM parameters to rock properties. This is necessary in order to use correct reservoir geomechanical properties during modeling. For any type of particle packing there is a limitation that the maximum ratio between P- and S-wave velocity Vp/Vs that can be modeled is 3 . The static behavior for a loose packing is different from the dynamic behavior. Empirical relations are needed for the static behavior based on numerical test observations. The dynamic behavior for both dense and loose packing can be given by analytical relations. Cosserat continuum theory is needed to derive relations for Vp and Vs. It is shown that by constraining the particle rotation, the S-wave velocity can be

Tracking the movement of Hawaiian volcanoes; Global Positioning System (GPS) measurement

Science.gov (United States)

Dvorak, J.J.

1992-01-01

Most, if not all, volcanic eruptions are preceded by surface movements near the volcano. These ground movements are the response of the shallow crust to the accumulation of the magma or the buildup of magma pressure within a subterranean reservoir beneath the volcano. As the magma reservoir expands, the summit and the flanks of the volcano rise and spread apart. Measurements made at many volcanoes show that slow ground movement may precede an eruption by as many as several years. Sudden increases in the rate of ground movement often precede an eruption by a few hours or days.

The Controls of Pore-Throat Structure on Fluid Performance in Tight Clastic Rock Reservoir: A Case from the Upper Triassic of Chang 7 Member, Ordos Basin, China

Directory of Open Access Journals (Sweden)

Yunlong Zhang

2018-01-01

Full Text Available The characteristics of porosity and permeability in tight clastic rock reservoir have significant difference from those in conventional reservoir. The increased exploitation of tight gas and oil requests further understanding of fluid performance in the nanoscale pore-throat network of the tight reservoir. Typical tight sandstone and siltstone samples from Ordos Basin were investigated, and rate-controlled mercury injection capillary pressure (RMICP and nuclear magnetic resonance (NMR were employed in this paper, combined with helium porosity and air permeability data, to analyze the impact of pore-throat structure on the storage and seepage capacity of these tight oil reservoirs, revealing the control factors of economic petroleum production. The researches indicate that, in the tight clastic rock reservoir, largest throat is the key control on the permeability and potentially dominates the movable water saturation in the reservoir. The storage capacity of the reservoir consists of effective throat and pore space. Although it has a relatively steady and significant proportion that resulted from the throats, its variation is still dominated by the effective pores. A combination parameter (ε that was established to be as an integrated characteristic of pore-throat structure shows effectively prediction of physical capability for hydrocarbon resource of the tight clastic rock reservoir.

Fracture Evolution Following a Hydraulic Stimulation within an EGS Reservoir

Energy Technology Data Exchange (ETDEWEB)

Mella, Michael [Univ. of Utah, Salt Lake City, UT (United States). Energy and Geoscience Inst.

2016-08-31

The objective of this project was to develop and demonstrate an approach for tracking the evolution of circulation immediately following a hydraulic stimulation in an EGS reservoir. Series of high-resolution tracer tests using conservative and thermally reactive tracers were designed at recently created EGS reservoirs in order to track changes in fluid flow parameters such as reservoir pore volume, flow capacity, and effective reservoir temperature over time. Data obtained from the project would be available for the calibration of reservoir models that could serve to predict EGS performance following a hydraulic stimulation.

Impacts of hydro-electric reservoir on populations of caribou and grizzly bear in southern British Columbia

International Nuclear Information System (INIS)

Simpson, K.

1987-02-01

The impacts of a hydroelectric reservoir on populations of caribou and grizzly bear were studied north of Revelstoke, British Columbia. Information collected for 3 years prior to flooding was compared with data collected in 1984-85. The reservoir did not obstruct movement of caribou and animals did not attempt crossing during periods when ice conditions were hazardous. Evidence suggested that predator avoidance was the most important determinant of habitats used in spring. The cleared reservoir was an important habitat for caribou in the spring because of the abundant food and security from predators it offered. A potential decline in caribou recruitment was noted in 1985 coincident with reservoir flooding. Mitigative recommendations include clearing logged areas adjacent to formerly used reservoir habitats and maintaining movement corridors of mature timber between seasonal habitats. Inconclusive evidence suggested that the reservoir was a barrier to grizzly movement. Spring movements of grizzly were mainly related to finding good feeding sites. Avalanche paths in side drainages were the principal habitats used. Cleared areas did provide an abundance of food comparable to naturally disturbed habitats. The main impact of flooding was to shift habitat use of bears from relatively secure areas in the reservoir to high-risk habitats on the highway and power line rights-of-way. Mitigative recommendations include reducing the attractiveness of those rights-of-way and maintaining spring ranges in tributary valleys by careful development planning. 14 refs., 7 figs., 17 tabs

Impacts of hydro-electric reservoir on populations of caribou and grizzly bear in southern British Columbia

Energy Technology Data Exchange (ETDEWEB)

Simpson, K.

1987-02-01

The impacts of a hydroelectric reservoir on populations of caribou and grizzly bear were studied north of Revelstoke, British Columbia. Information collected for 3 years prior to flooding was compared with data collected in 1984-85. The reservoir did not obstruct movement of caribou and animals did not attempt crossing during periods when ice conditions were hazardous. Evidence suggested that predator avoidance was the most important determinant of habitats used in spring. The cleared reservoir was an important habitat for caribou in the spring because of the abundant food and security from predators it offered. A potential decline in caribou recruitment was noted in 1985 coincident with reservoir flooding. Mitigative recommendations include clearing logged areas adjacent to formerly used reservoir habitats and maintaining movement corridors of mature timber between seasonal habitats. Inconclusive evidence suggested that the reservoir was a barrier to grizzly movement. Spring movements of grizzly were mainly related to finding good feeding sites. Avalanche paths in side drainages were the principal habitats used. Cleared areas did provide an abundance of food comparable to naturally disturbed habitats. The main impact of flooding was to shift habitat use of bears from relatively secure areas in the reservoir to high-risk habitats on the highway and power line rights-of-way. Mitigative recommendations include reducing the attractiveness of those rights-of-way and maintaining spring ranges in tributary valleys by careful development planning. 14 refs., 7 figs., 17 tabs.

Pore Fluid Evolution Influenced by Volcanic Activities and Related Diagenetic Processes in a Rift Basin: Evidence from the Paleogene Medium-Deep Reservoirs of Huanghekou Sag, Bohai Bay Basin, China

Directory of Open Access Journals (Sweden)

Zhongheng Sun

2017-01-01

Full Text Available Volcanic activities exert a significant influence on pore fluid property and related diagenetic processes that substantially controlled reservoirs quality. Analysis of Paleogene medium-deep sandstones on the Huanghekou Sag provides insight into relating the diagenetic processes to pore fluid property evolution influenced by volcanic activities. Three distinct types of pore fluids were identified on the basis of an integrated and systematic analysis including core and thin section observation, XRD, SEM, CL, and trace element. Alkaline aqueous medium environment occurred in E2s1+2 where volcanic activities have insignificant influence on pore fluids, evidenced by typical alkaline diagenetic events such as K-feldspar albitization, quartz dissolution, feldspar dissolution, and carbonate cementation. During the deposition of E3d3, influx of terrestrial freshwater and alteration of ferromagnesian-rich pore water result in the formation of mixing aqueous medium environment through volcanic eruption dormancy causing zeolite dissolution, clay mineral transformation, and K-feldspar albitization. Ferromagnesian-rich aqueous medium environment developed resulting from the intensive hydrolysis of the unstable ferromagnesian minerals formed due to intense volcanic activities during E3d1+2 and corresponding predominant diagenetic processes were characterized by the precipitation and dissolution of low-silica zeolites. Therefore, the differential properties of pore fluids caused various diagenetic processes controlling reservoir quality.

Final Report to DOE EERE – Geothermal Technologies Program Project Title: Monitoring and modeling of fluid flow in a developing enhanced geothermal system (EGS) reservoir

Energy Technology Data Exchange (ETDEWEB)

Fehler, Michael [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

2017-04-19

The primary objective of this project was to improve our ability to predict performance of an Enhanced Geothermal System (EGS) reservoir over time by relating, in a quantitative manner, microseismic imaging with fluid and temperature changes within the reservoir. Historically, microseismic data have been used qualitatively to place bounds on the growth of EGS reservoirs created by large hydraulic fracturing experiments. Previous investigators used an experimentally based fracture opening relationship (fracture aperture as a function of pressure), the spatial extent of microseismic events, and some assumptions about fracture frequency to determine the size of an EGS reservoir created during large pumping tests. We addressed a number of issues (1) locating microearthquakes that occur during hydraulic fracturing, (2) obtaining more information about a reservoir than the microearthquake locations from the microearthquake data, for example, information about the seismic velocity structure of the reservoir or the scattering of seismic waves within the reservoir, (3) developing an improved methodology for estimating properties of fractures that intersect wellbores in a reservoir, and (4) developing a conceptual model for explaining the downward growth of observed seismicity that accompanies some hydraulic injections into geothermal reservoirs. We used two primary microseismic datasets for our work. The work was motivated by a dataset from the Salak Geothermal Field in Indonesia where seismicity accompanying a hydraulic injection was observed to migrate downward. We also used data from the Soultz EGS site in France. We also used Vertical Seismic Profiling data from a well in the United States. The work conducted is of benefit for characterizing reservoirs that are created by hydraulic fracturing for both EGS and for petroleum recovery.

The Coupling Effect of Rainfall and Reservoir Water Level Decline on the Baijiabao Landslide in the Three Gorges Reservoir Area, China

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Nenghao Zhao

2017-01-01

Full Text Available Rainfall and reservoir level fluctuation are two of the main factors contributing to reservoir landslides. However, in China’s Three Gorges Reservoir Area, when the reservoir water level fluctuates significantly, it comes at a time of abundant rainfall, which makes it difficult to distinguish which factor dominates the deformation of the landslide. This study focuses on how rainfall and reservoir water level decline affect the seepage and displacement field of Baijiabao landslide spatially and temporally during drawdown of reservoir water level in the Three Gorges Reservoir Area, thus exploring its movement mechanism. The monitoring data of the landslide in the past 10 years were analyzed, and the correlation between rainfall, reservoir water level decline, and landslide displacement was clarified. By the numerical simulation method, the deformation evolution mechanism of this landslide during drawdown of reservoir water level was revealed, respectively, under three conditions, namely, rainfall, reservoir water level decline, and coupling of the above two conditions. The results showed that the deformation of the Baijiabao landslide was the coupling effect of rainfall and reservoir water level decline, while the latter effect is more pronounced.

Estimation of Oil Production Rates in Reservoirs Exposed to Focused Vibrational Energy

KAUST Repository

Jeong, Chanseok

2014-01-01

Elastic wave-based enhanced oil recovery (EOR) is being investigated as a possible EOR method, since strong wave motions within an oil reservoir - induced by earthquakes or artificially generated vibrations - have been reported to improve the production rate of remaining oil from existing oil fields. To date, there are few theoretical studies on estimating how much bypassed oil within an oil reservoir could be mobilized by such vibrational stimulation. To fill this gap, this paper presents a numerical method to estimate the extent to which the bypassed oil is mobilized from low to high permeability reservoir areas, within a heterogeneous reservoir, via wave-induced cross-flow oscillation at the interface between the two reservoir permeability areas. This work uses the finite element method to numerically obtain the pore fluid wave motion within a one-dimensional fluid-saturated porous permeable elastic solid medium embedded in a non-permeable elastic semi-infinite solid. To estimate the net volume of mobilized oil from the low to the high permeability area, a fluid flow hysteresis hypothesis is adopted to describe the behavior at the interface between the two areas. Accordingly, the fluid that is moving from the low to the high permeability areas is assumed to transport a larger volume of oil than the fluid moving in the opposite direction. The numerical experiments were conducted by using a prototype heterogeneous oil reservoir model, subjected to ground surface dynamic loading operating at low frequencies (1 to 50 Hz). The numerical results show that a sizeable amount of oil could be mobilized via the elastic wave stimulation. It is observed that certain wave frequencies are more effective than others in mobilizing the remaining oil. We remark that these amplification frequencies depend on the formation’s elastic properties. This numerical work shows that the wave-based mobilization of the bypassed oil in a heterogeneous oil reservoir is feasible, especially

A Study of the Optimal Planning Model for Reservoir Sustainable Management- A Case Study of Shihmen Reservoir

Science.gov (United States)

Chen, Y. Y.; Ho, C. C.; Chang, L. C.

2017-12-01

The reservoir management in Taiwan faces lots of challenge. Massive sediment caused by landslide were flushed into reservoir, which will decrease capacity, rise the turbidity, and increase supply risk. Sediment usually accompanies nutrition that will cause eutrophication problem. Moreover, the unevenly distribution of rainfall cause water supply instability. Hence, how to ensure sustainable use of reservoirs has become an important task in reservoir management. The purpose of the study is developing an optimal planning model for reservoir sustainable management to find out an optimal operation rules of reservoir flood control and sediment sluicing. The model applies Genetic Algorithms to combine with the artificial neural network of hydraulic analysis and reservoir sediment movement. The main objective of operation rules in this study is to prevent reservoir outflow caused downstream overflow, minimum the gap between initial and last water level of reservoir, and maximum sluicing sediment efficiency. A case of Shihmen reservoir was used to explore the different between optimal operating rule and the current operation of the reservoir. The results indicate optimal operating rules tended to open desilting tunnel early and extend open duration during flood discharge period. The results also show the sluicing sediment efficiency of optimal operating rule is 36%, 44%, 54% during Typhoon Jangmi, Typhoon Fung-Wong, and Typhoon Sinlaku respectively. The results demonstrate the optimal operation rules do play a role in extending the service life of Shihmen reservoir and protecting the safety of downstream. The study introduces a low cost strategy, alteration of operation reservoir rules, into reservoir sustainable management instead of pump dredger in order to improve the problem of elimination of reservoir sediment and high cost.

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.

Heavy oil reservoir evaluation : performing an injection test using DST tools in the marine region of Mexico

Energy Technology Data Exchange (ETDEWEB)

Loaiza, J.; Ruiz, P. [Halliburton, Mexico City (Mexico); Barrera, D.; Gutierrez, F. [Pemex, Mexico City (Mexico)

2010-07-01

This paper described an injection test conducted to evaluate heavy oil reserves in an offshore area of Mexico. The drill-stem testing (DST) evaluation used a fluid injection technique in order to eliminate the need for artificial lift and coiled tubing. A pressure transient analysis method was used to determine the static pressure of the reservoir, effective hydrocarbon permeability, and formation damage. Boundary effects were also characterized. The total volume of the fluid injection was determined by analyzing various reservoir parameters. The timing of the shut-in procedure was determined by characterizing rock characteristics and fluids within the reservoir. The mobility and diffusivity relationships between the zones with the injection fluids and reservoir fluids were used to defined sweep fluids. A productivity analysis was used to predict various production scenarios. DST tools were then used to conduct a pressure-production assessment. Case histories were used to demonstrate the method. The studies showed that the method provides a cost-effective means of providing high quality data for productivity analyses. 4 refs., 2 tabs., 15 figs.

Effects of intermediary reservoir in a two-stage impedance pump

Directory of Open Access Journals (Sweden)

Lee V. C.-C.

2017-01-01

Full Text Available Impedance pump is a simple valve-less pumping mechanism, which transport fluid through the mismatch of impedance in the system. A typical open-loop impedance pump consists of an elastic tube, connected to rigid tubing, where the rigid section is connected to a reservoir. Mismatch in impedance occurs when an asymmetrical periodic excitation is exerted on the elastic tube. Studies showed that sequential excitations on the elastic tube infers higher volumetric efficiency than a single excitation. This work studies the effects of an intermediary reservoir between two excitation points on an elastic tube. This study aims to shed some light on the steady state response and fluid motion within the intermediary reservoir; in which increased volumetric efficiency is demonstrated.

Synergizing Crosswell Seismic and Electromagnetic Techniques for Enhancing Reservoir Characterization

KAUST Repository

Katterbauer, Klemens

2015-11-18

Increasing complexity of hydrocarbon projects and the request for higher recovery rates have driven the oil-and-gas industry to look for a more-detailed understanding of the subsurface formation to optimize recovery of oil and profitability. Despite the significant successes of geophysical techniques in determining changes within the reservoir, the benefits from individually mapping the information are limited. Although seismic techniques have been the main approach for imaging the subsurface, the weak density contrast between water and oil has made electromagnetic (EM) technology an attractive complement to improve fluid distinction, especially for high-saline water. This crosswell technology assumes greater importance for obtaining higher-resolution images of the interwell regions to more accurately characterize the reservoir and track fluid-front developments. In this study, an ensemble-Kalman-based history-matching framework is proposed for directly incorporating crosswell time-lapse seismic and EM data into the history-matching process. The direct incorporation of the time-lapse seismic and EM data into the history-matching process exploits the complementarity of these data to enhance subsurface characterization, to incorporate interwell information, and to avoid biases that may be incurred from separate inversions of the geophysical data for attributes. An extensive analysis with 2D and realistic 3D reservoirs illustrates the robustness and enhanced forecastability of critical reservoir variables. The 2D reservoir provides a better understanding of the connection between fluid discrimination and enhanced history matches, and the 3D reservoir demonstrates its applicability to a realistic reservoir. History-matching enhancements (in terms of reduction in the history-matching error) when incorporating both seismic and EM data averaged approximately 50% for the 2D case, and approximately 30% for the 3D case, and permeability estimates were approximately 25

Advancing Reactive Tracer Methods for Measurement of Thermal Evolution in Geothermal Reservoirs: Final Report

Energy Technology Data Exchange (ETDEWEB)

Mitchell A. Plummer; Carl D. Palmer; Earl D. Mattson; Laurence C. Hull; George D. Redden

2011-07-01

The injection of cold fluids into engineered geothermal system (EGS) and conventional geothermal reservoirs may be done to help extract heat from the subsurface or to maintain pressures within the reservoir (e.g., Rose et al., 2001). As these injected fluids move along fractures, they acquire heat from the rock matrix and remove it from the reservoir as they are extracted to the surface. A consequence of such injection is the migration of a cold-fluid front through the reservoir (Figure 1) that could eventually reach the production well and result in the lowering of the temperature of the produced fluids (thermal breakthrough). Efficient operation of an EGS as well as conventional geothermal systems involving cold-fluid injection requires accurate and timely information about thermal depletion of the reservoir in response to operation. In particular, accurate predictions of the time to thermal breakthrough and subsequent rate of thermal drawdown are necessary for reservoir management, design of fracture stimulation and well drilling programs, and forecasting of economic return. A potential method for estimating migration of a cold front between an injection well and a production well is through application of reactive tracer tests, using chemical whose rate of degradation is dependent on the reservoir temperature between the two wells (e.g., Robinson 1985). With repeated tests, the rate of migration of the thermal front can be determined, and the time to thermal breakthrough calculated. While the basic theory behind the concept of thermal tracers has been understood for some time, effective application of the method has yet to be demonstrated. This report describes results of a study that used several methods to investigate application of reactive tracers to monitoring the thermal evolution of a geothermal reservoir. These methods included (1) mathematical investigation of the sensitivity of known and hypothetical reactive tracers, (2) laboratory testing of novel

Design Techniques and Reservoir Simulation

Directory of Open Access Journals (Sweden)

Ahad Fereidooni

2012-11-01

Full Text Available Enhanced oil recovery using nitrogen injection is a commonly applied method for pressure maintenance in conventional reservoirs. Numerical simulations can be practiced for the prediction of a reservoir performance in the course of injection process; however, a detailed simulation might take up enormous computer processing time. In such cases, a simple statistical model may be a good approach to the preliminary prediction of the process without any application of numerical simulation. In the current work, seven rock/fluid reservoir properties are considered as screening parameters and those parameters having the most considerable effect on the process are determined using the combination of experimental design techniques and reservoir simulations. Therefore, the statistical significance of the main effects and interactions of screening parameters are analyzed utilizing statistical inference approaches. Finally, the influential parameters are employed to create a simple statistical model which allows the preliminary prediction of nitrogen injection in terms of a recovery factor without resorting to numerical simulations.

Improving reservoir history matching of EM heated heavy oil reservoirs via cross-well seismic tomography

KAUST Repository

Katterbauer, Klemens

2014-01-01

Enhanced recovery methods have become significant in the industry\\'s drive to increase recovery rates from oil and gas reservoirs. For heavy oil reservoirs, the immobility of the oil at reservoir temperatures, caused by its high viscosity, limits the recovery rates and strains the economic viability of these fields. While thermal recovery methods, such as steam injection or THAI, have extensively been applied in the field, their success has so far been limited due to prohibitive heat losses and the difficulty in controlling the combustion process. Electromagnetic (EM) heating via high-frequency EM radiation has attracted attention due to its wide applicability in different environments, its efficiency, and the improved controllability of the heating process. While becoming a promising technology for heavy oil recovery, its effect on overall reservoir production and fluid displacements are poorly understood. Reservoir history matching has become a vital tool for the oil & gas industry to increase recovery rates. Limited research has been undertaken so far to capture the nonlinear reservoir dynamics and significantly varying flow rates for thermally heated heavy oil reservoir that may notably change production rates and render conventional history matching frameworks more challenging. We present a new history matching framework for EM heated heavy oil reservoirs incorporating cross-well seismic imaging. Interfacing an EM heating solver to a reservoir simulator via Andrade’s equation, we couple the system to an ensemble Kalman filter based history matching framework incorporating a cross-well seismic survey module. With increasing power levels and heating applied to the heavy oil reservoirs, reservoir dynamics change considerably and may lead to widely differing production forecasts and increased uncertainty. We have shown that the incorporation of seismic observations into the EnKF framework can significantly enhance reservoir simulations, decrease forecasting

IMPROVING CO2 EFFICIENCY FOR RECOVERING OIL IN HETEROGENEOUS RESERVOIRS

International Nuclear Information System (INIS)

Grigg, Reid B.

2002-01-01

A three-year contract, 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. This report discusses the activity during the six-month period covering January 1, 2002 through June 30, 2002 that covers the second and third fiscal quarters of the project's first year. Paper SPE 75178, ''Cost Reduction and Injectivity Improvements for CO 2 Foams for Mobility Control,'' has been presented and included in the proceedings of the SPE/DOE Thirteenth Symposium on Improved Oil Recovery, Tulsa, OK, April 13-17, 2002. During these two quarters of the project we have been working in several areas: reservoir fluid/rock interactions and their relationships to changing injectivity, producer survey on injectivity, and surfactant adsorption on quarried and reservoir core

Major occurrences and reservoir concepts of marine clathrate hydrates: Implications of field evidence

Science.gov (United States)

Booth, J.S.; Winters, W.J.; Dillon, William P.; Clennell, M.B.; Rowe, M.M.

1998-01-01

This paper is part of the special publication Gas hydrates: relevance to world margin stability and climatic change (eds J.P. Henriet and J. Mienert). Questions concerning clathrate hydrate as an energy resource, as a factor in modifying global climate and as a triggering mechanism for mass movements invite consideration of what factors promote hydrate concentration, and what the quintessential hydrate-rich sediment may be. Gas hydrate field data, although limited, provide a starting point for identifying the environments and processes that lead to more massive concentrations. Gas hydrate zones are up to 30 m thick and the vertical range of occurrence at a site may exceed 200 m. Zones typically occur more than 100m above the phase boundary. Thicker zones are overwhelmingly associated with structural features and tectonism, and often contain sand. It is unclear whether an apparent association between zone thickness and porosity represents a cause-and-effect relationship. The primary control on the thickness of a potential gas hydrate reservoir is the geological setting. Deep water and low geothermal gradients foster thick gas hydrate stability zones (GHSZs). The presence of faults, fractures, etc. can favour migration of gas-rich fluids. Geological processes, such as eustacy or subsidence, may alter the thickness of the GHSZ or affect hydrate concentratiion. Tectonic forces may promote injection of gas into the GHSZ. More porous and permeable sediment, as host sediment properties, increase storage capacity and fluid conductivity, and thus also enhance reservoir potential.

Coupling of a reservoir model and of a poro-mechanical model. Application to the study of the compaction of petroleum reservoirs and of the associated subsidence; Couplage d'un modele de gisement et d'un modele mecanique. Application a l'etude de la compaction des reservoirs petroliers et de la subsidence associee

Energy Technology Data Exchange (ETDEWEB)

Bevillon, D.

2000-11-30

The aim of this study is to provide a better description of the rock contribution to fluid flows in petroleum reservoirs. The production of oil/gas in soft highly compacting reservoirs induces important reduction of the pore volume, which increases oil productivity. This compaction leads to undesirable effects such as surface subsidence or damage of well equipment. Analysis of compaction and subsidence can be performed using either engineering reservoir models or coupled poro-mechanical models. Poro-mechanical model offers a rigorous mechanical framework, but does not permit a complete description of the fluids. The reservoir model gives a good description of the fluid phases, but the description of the mechanic phenomenon is then simplified. To satisfy the set of equations (mechanical equilibrium and diffusivity equations), two simulators can be used together sequentially. Each of the two simulators solves its own system independently, and information passed both directions between simulators. This technique is usually referred to the partially coupled scheme. In this study, reservoir and hydro-mechanical simulations show that reservoir theory is not a rigorous framework to represent the evolution of the high porous rocks strains. Then, we introduce a partially coupled scheme that is shown to be consistent and unconditionally stable, which permits to describe correctly poro-mechanical theory in reservoir models. (author)

Multilevel techniques for Reservoir Simulation

DEFF Research Database (Denmark)

Christensen, Max la Cour

The subject of this thesis is the development, application and study of novel multilevel methods for the acceleration and improvement of reservoir simulation techniques. The motivation for addressing this topic is a need for more accurate predictions of porous media flow and the ability to carry...... Full Approximation Scheme) • Variational (Galerkin) upscaling • Linear solvers and preconditioners First, a nonlinear multigrid scheme in the form of the Full Approximation Scheme (FAS) is implemented and studied for a 3D three-phase compressible rock/fluids immiscible reservoir simulator...... is extended to include a hybrid strategy, where FAS is combined with Newton’s method to construct a multilevel nonlinear preconditioner. This method demonstrates high efficiency and robustness. Second, an improved IMPES formulated reservoir simulator is implemented using a novel variational upscaling approach...

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.

Uncertainty in forecasting breakthrough of fluid transported through fractures

International Nuclear Information System (INIS)

Horne, R.N.

1989-01-01

Tracer experiments in geothermal reservoirs emphasize the very great variability in rates of fluid movement through fractured rocks. This variability extends from the 10-meter to the kilometer-length scale. Thus tracer returns have been observed at some locations within hours at distances of up to 1 kilometer from the injection point, while other much nearer locations in the same formation do not observe the tracer until much later. In addition, transport rates have sometimes been extremely fast (up to 100 m/hr) even over such distances. This paper discusses the conclusions reached after compiling the results of a large number of tracer tests in several different fractured reservoirs. It is evident in some cases that large-scale geological features, such as faults, are responsible for the variations in tracer return time. In other cases, there is no clear physical description that explains the differences. These results suggest that there will be no a priori way of forecasting transport rates in fractured systems without performing a tracer test

Lattice Boltzmann Simulations of Fluid Flow in Continental Carbonate Reservoir Rocks and in Upscaled Rock Models Generated with Multiple-Point Geostatistics

Directory of Open Access Journals (Sweden)

J. Soete

2017-01-01

Full Text Available Microcomputed tomography (μCT and Lattice Boltzmann Method (LBM simulations were applied to continental carbonates to quantify fluid flow. Fluid flow characteristics in these complex carbonates with multiscale pore networks are unique and the applied method allows studying their heterogeneity and anisotropy. 3D pore network models were introduced to single-phase flow simulations in Palabos, a software tool for particle-based modelling of classic computational fluid dynamics. In addition, permeability simulations were also performed on rock models generated with multiple-point geostatistics (MPS. This allowed assessing the applicability of MPS in upscaling high-resolution porosity patterns into large rock models that exceed the volume limitations of the μCT. Porosity and tortuosity control fluid flow in these porous media. Micro- and mesopores influence flow properties at larger scales in continental carbonates. Upscaling with MPS is therefore necessary to overcome volume-resolution problems of CT scanning equipment. The presented LBM-MPS workflow is applicable to other lithologies, comprising different pore types, shapes, and pore networks altogether. The lack of straightforward porosity-permeability relationships in complex carbonates highlights the necessity for a 3D approach. 3D fluid flow studies provide the best understanding of flow through porous media, which is of crucial importance in reservoir modelling.

Fluid discrimination based on rock physics templates

International Nuclear Information System (INIS)

Liu, Qian; Yin, Xingyao; Li, Chao

2015-01-01

Reservoir fluid discrimination is an indispensable part of seismic exploration. Reliable fluid discrimination helps to decrease the risk of exploration and to increase the success ratio of drilling. There are many kinds of fluid indicators that are used in fluid discriminations, most of which are single indicators. But single indicators do not always work well under complicated reservoir conditions. Therefore, combined fluid indicators are needed to increase accuracies of discriminations. In this paper, we have proposed an alternative strategy for the combination of fluid indicators. An alternative fluid indicator, the rock physics template-based indicator (RPTI) has been derived to combine the advantages of two single indicators. The RPTI is more sensitive to the contents of fluid than traditional indicators. The combination is implemented based on the characteristic of the fluid trend in the rock physics template, which means few subjective factors are involved. We also propose an inversion method to assure the accuracy of the RPTI input data. The RPTI profile is an intuitionistic interpretation of fluid content. Real data tests demonstrate the applicability and validity. (paper)

Coupling a fluid flow simulation with a geomechanical model of a fractured reservoir

OpenAIRE

Segura Segarra, José María; Paz, C.M.; de Bayser, M.; Zhang, J.; Bryant, P.W.; Gonzalez, Nubia Aurora; Rodrigues, E.; Vargas, P.E.; Carol, Ignacio; Lakshmikantha, Ramasesha Mookanahallipatna; Das, K. C.; Sandha, S.S.; Cerqueira, R.; Mello,, U.

2013-01-01

Improving the reliability of integrated reservoir development planning and addressing subsidence, fault reactivation and other environmental impacts, requires increasingly sophisticated geomechanical models, especially in the case of fractured reservoirs where fracture deformation is strongly coupled with its permeability change. Reservoir simulation has historically treated any geomechanical effects by means of a rock compressibility term/table, which can be improved by simulating the actual...

Markov-modulated and feedback fluid queues

NARCIS (Netherlands)

Scheinhardt, Willem R.W.

1998-01-01

In the last twenty years the field of Markov-modulated fluid queues has received considerable attention. In these models a fluid reservoir receives and/or releases fluid at rates which depend on the actual state of a background Markov chain. In the first chapter of this thesis we give a short

Thermochemical sulphate reduction can improve carbonate petroleum reservoir quality

Science.gov (United States)

Jiang, Lei; Worden, Richard H.; Yang, Changbing

2018-02-01

Interest in the creation of secondary pore spaces in petroleum reservoirs has increased because of a need to understand deeper and more complex reservoirs. The creation of new secondary porosity that enhances overall reservoir quality in deeply buried carbonate reservoirs is controversial and some recent studies have concluded it is not an important phenomenon. Here we present petrography, geochemistry, fluid inclusion data, and fluid-rock interaction reaction modeling results from Triassic Feixianguan Formation, Sichuan Basin, China, core samples and explore the relative importance of secondary porosity due to thermochemical sulphate reduction (TSR) during deep burial diagenesis. We find that new secondary pores result from the dissolution of anhydrite and possibly from dissolution of the matrix dolomite. Assuming porosity before TSR was 16% and the percentage of anhydrite was 6%, modelling shows that, due to TSR, 1.6% additional porosity was created that led to permeability increasing from 110 mD (range 72-168 mD within a 95% confidence interval) to 264 mD (range 162-432 mD within a 95% confidence interval). Secondary porosity results from the density differences between reactant anhydrite and product calcite, the addition of new water during TSR, and the generation of acidity during the reaction of new H2S with the siderite component in pre-existing dolomite in the reservoir. Fluid pressure was high during TSR, and approached lithostatic pressure in some samples; this transient overpressure may have led to the maintenance of porosity due to the inhibition of compactional processes. An additional 1.6% porosity is significant for reserve calculations, especially considering that it occurs in conjunction with elevated permeability that results in faster flow rates to the production wells.

Automobile windshield washer fluid: A potential source of transmission for Legionella

International Nuclear Information System (INIS)

Schwake, David Otto; Alum, Absar; Abbaszadegan, Morteza

2015-01-01

Epidemiological evidence suggesting driving cars to be a risk factor for legionellosis has prompted public health studies to investigate vehicle windshield washer fluid as a novel transmission source of this disease. The goal of the current study was to investigate whether or not windshield washer fluid could serve as a potential source of transmission for Legionella. A wide variation in the survival of L. pneumophila was observed when incubated in different washer fluids at 25 and 37 °C, however, one brand tested supported Legionella survival similar to or greater than sterilized deionized water. In addition, 1 L of tap water contained in a washer fluid reservoir was able to support population growth and survival of Legionella for several months. In a field study examining the windshield washer fluid of 12 elementary school buses, Legionella were detected from 84% of samples at a high concentration of 8.1 × 10 4 CFU/mL. Culturable cells were also detected in aerosolized washer fluid during washer fluid spray. By demonstrating survival in certain windshield washer fluids, growth within washer fluid reservoirs, and the presence of viable cells in bus washer fluid spray, we have provided evidence suggesting the potential for a novel route of Legionella exposure. - Highlights: • L. pneumophila survival in one brand of washer fluid and sterilized deionized water were similar. • Legionella population was maintained in tap water for several months. • Culturable Legionella were detected in 10 of 12 school bus washer fluid reservoirs sampled. • Legionella concentrations up to 8.1 × 104 CFU/mL were detected in school bus washer fluid. • L. pneumophila was detected in washer fluid reservoirs and aerosolized washer fluid

Automobile windshield washer fluid: A potential source of transmission for Legionella

Energy Technology Data Exchange (ETDEWEB)

Schwake, David Otto [School of Life Sciences, Arizona State University, P.O. Box 875306, Tempe, AZ 85287 (United States); Alum, Absar [School of Sustainable Engineering and the Built Environment, Arizona State University, P.O. Box 875306, Tempe, AZ 85287 (United States); Abbaszadegan, Morteza, E-mail: abbaszadegan@asu.edu [School of Sustainable Engineering and the Built Environment, Arizona State University, P.O. Box 875306, Tempe, AZ 85287 (United States)

2015-09-01

Epidemiological evidence suggesting driving cars to be a risk factor for legionellosis has prompted public health studies to investigate vehicle windshield washer fluid as a novel transmission source of this disease. The goal of the current study was to investigate whether or not windshield washer fluid could serve as a potential source of transmission for Legionella. A wide variation in the survival of L. pneumophila was observed when incubated in different washer fluids at 25 and 37 °C, however, one brand tested supported Legionella survival similar to or greater than sterilized deionized water. In addition, 1 L of tap water contained in a washer fluid reservoir was able to support population growth and survival of Legionella for several months. In a field study examining the windshield washer fluid of 12 elementary school buses, Legionella were detected from 84% of samples at a high concentration of 8.1 × 10{sup 4} CFU/mL. Culturable cells were also detected in aerosolized washer fluid during washer fluid spray. By demonstrating survival in certain windshield washer fluids, growth within washer fluid reservoirs, and the presence of viable cells in bus washer fluid spray, we have provided evidence suggesting the potential for a novel route of Legionella exposure. - Highlights: • L. pneumophila survival in one brand of washer fluid and sterilized deionized water were similar. • Legionella population was maintained in tap water for several months. • Culturable Legionella were detected in 10 of 12 school bus washer fluid reservoirs sampled. • Legionella concentrations up to 8.1 × 104 CFU/mL were detected in school bus washer fluid. • L. pneumophila was detected in washer fluid reservoirs and aerosolized washer fluid.

SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

Energy Technology Data Exchange (ETDEWEB)

Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

2003-12-01

We have developed and tested technology for a new type of direct hydrocarbon detection. The method uses inelastic rock properties to greatly enhance the sensitivity of surface seismic methods to the presence of oil and gas saturation. These methods include use of energy absorption, dispersion, and attenuation (Q) along with traditional seismic attributes like velocity, impedance, and AVO. Our approach is to combine three elements: (1) a synthesis of the latest rock physics understanding of how rock inelasticity is related to rock type, pore fluid types, and pore microstructure, (2) synthetic seismic modeling that will help identify the relative contributions of scattering and intrinsic inelasticity to apparent Q attributes, and (3) robust algorithms that extract relative wave attenuation attributes from seismic data. This project provides: (1) Additional petrophysical insight from acquired data; (2) Increased understanding of rock and fluid properties; (3) New techniques to measure reservoir properties that are not currently available; and (4) Provide tools to more accurately describe the reservoir and predict oil location and volumes. These methodologies will improve the industry's ability to predict and quantify oil and gas saturation distribution, and to apply this information through geologic models to enhance reservoir simulation. We have applied for two separate patents relating to work that was completed as part of this project.

Interactions of fluid and gas movement and faulting in the Colorado Plateau, southeastern Utah

Science.gov (United States)

Shipton, Z. K.; Evans, J. P.; Kirschner, D.; Heath, J.; Williams, A.; Dockrill, B.

2002-12-01

The east-west and west-northwest striking Salt Wash and the Little Grand Wash normal faults in the Colorado Plateau of southeastern Utah emit large amounts of CO2 gas from abandon drill holes, springs and a hydrocarbon seep. The leakage of similar CO2 charged water has also occurred in the past as shown by large localized tufa deposits and horizontal veins along the fault traces. These deposits consist of thick tufa terraces and mound extending up to 50 meters from the fault damage zones. The faults cut a north plunging anticline of siltstones, shales, and sandstones, and the fault rocks are fine-grained with clay-rich gouge. The Little Grand Wash fault displaces these rocks approximately 290 m and the Salt Wash graben offsets rocks approximately 130 m; both faults extend at least to the top of the Pennsylvanian Paradox Formation, which contains thick salt horizons 1.5 - 2 km at depth. Well log, geologic surface and geochemical data indicate the CO2 reservoirs and sources have been cut by the faults at depth providing a conduit for the vertical migration of CO2 to the surface, but limited horizontal flow across the fault plane. Three- dimensional flow modals show how the faults damage zones permeability is adjacent to the faults and the leakage though the damage zones is localized near the regional anticlines fold axis. Analysis of the fluids emanating from the faults aims to locate the sources and determine the chemical evolutions of the fluids. δ2H and δ18O isotopic data show that the ground waters are meteoric and have not circulated deeply enough to experience an oxygen-isotope shift. δ13C data and PCO2 values indicate that the gas is external to the ground water systems (i.e., not from soil zone gas or dissolution of carbonate aquifer material alone). 3He/4He ratio 0.30 - 0.31 from springs and geysers indicate that the majority of the gas is crustally derived and contains a minimal component of mantle or magmatic gases. δ13C values of 4 to 5 per mil from

Physical Model-Based Investigation of Reservoir Sedimentation Processes

Directory of Open Access Journals (Sweden)

Cheng-Chia Huang

2018-03-01

Full Text Available Sedimentation is a serious problem in the operations of reservoirs. In Taiwan, the situation became worse after the Chi-Chi Earthquake recorded on 21 September 1999. The sediment trap efficiency in several regional reservoirs has been sharply increased, adversely affecting the operations on water supplies. According to the field record, the average annual sediment deposition observed in several regional reservoirs in Taiwan has been increased. For instance, the typhoon event recorded in 2008 at the Wushe Reservoir, Taiwan, produced a 3 m sediment deposit upstream of the dam. The remaining storage capacity in the Wushe Reservoir was reduced to 35.9% or a volume of 53.79 million m3 for flood water detention in 2010. It is urgent that research should be conducted to understand the sediment movement in the Wushe Reservoir. In this study, a scale physical model was built to reproduce the flood flow through the reservoir, investigate the long-term depositional pattern, and evaluate sediment trap efficiency. This allows us to estimate the residual life of the reservoir by proposing a modification of Brune’s method. It can be presented to predict the lifespan of Taiwan reservoirs due to higher applicability in both the physical model and the observed data.

FRACTURING FLUID CHARACTERIZATION FACILITY

Energy Technology Data Exchange (ETDEWEB)

Subhash Shah

2000-08-01

Hydraulic fracturing technology has been successfully applied for well stimulation of low and high permeability reservoirs for numerous years. Treatment optimization and improved economics have always been the key to the success and it is more so when the reservoirs under consideration are marginal. Fluids are widely used for the stimulation of wells. The Fracturing Fluid Characterization Facility (FFCF) has been established to provide the accurate prediction of the behavior of complex fracturing fluids under downhole conditions. The primary focus of the facility is to provide valuable insight into the various mechanisms that govern the flow of fracturing fluids and slurries through hydraulically created fractures. During the time between September 30, 1992, and March 31, 2000, the research efforts were devoted to the areas of fluid rheology, proppant transport, proppant flowback, dynamic fluid loss, perforation pressure losses, and frictional pressure losses. In this regard, a unique above-the-ground fracture simulator was designed and constructed at the FFCF, labeled ''The High Pressure Simulator'' (HPS). The FFCF is now available to industry for characterizing and understanding the behavior of complex fluid systems. To better reflect and encompass the broad spectrum of the petroleum industry, the FFCF now operates under a new name of ''The Well Construction Technology Center'' (WCTC). This report documents the summary of the activities performed during 1992-2000 at the FFCF.

The multiphase flow system used in exploiting depleted reservoirs: water-based Micro-bubble drilling fluid

International Nuclear Information System (INIS)

Zheng Lihui; He Xiaoqing; Wang Xiangchun; Fu Lixia

2009-01-01

Water-based micro-bubble drilling fluid, which is used to exploit depleted reservoirs, is a complicated multiphase flow system that is composed of gas, water, oil, polymer, surfactants and solids. The gas phase is separate from bulk water by two layers and three membranes. They are 'surface tension reducing membrane', 'high viscosity layer', 'high viscosity fixing membrane', 'compatibility enhancing membrane' and 'concentration transition layer of liner high polymer (LHP) and surfactants' from every gas phase centre to the bulk water. 'Surface tension reducing membrane', 'high viscosity layer' and 'high viscosity fixing membrane' bond closely to pack air forming 'air-bag', 'compatibility enhancing membrane' and 'concentration transition layer of LHP and surfactants' absorb outside 'air-bag' to form 'incompact zone'. From another point of view, 'air-bag' and 'incompact zone' compose micro-bubble. Dynamic changes of 'incompact zone' enable micro-bubble to exist lonely or aggregate together, and lead the whole fluid, which can wet both hydrophilic and hydrophobic surface, to possess very high viscosity at an extremely low shear rate but to possess good fluidity at a higher shear rate. When the water-based micro-bubble drilling fluid encounters leakage zones, it will automatically regulate the sizes and shapes of the bubbles according to the slot width of fracture, the height of cavern as well as the aperture of openings, or seal them by making use of high viscosity of the system at a very low shear rate. Measurements of the rheological parameters indicate that water-based micro-bubble drilling fluid has very high plastic viscosity, yield point, initial gel, final gel and high ratio of yield point and plastic viscosity. All of these properties make the multiphase flow system meet the requirements of petroleum drilling industry. Research on interface between gas and bulk water of this multiphase flow system can provide us with information of synthesizing effective

Noble gas and hydrocarbon tracers in multiphase unconventional hydrocarbon systems: Toward integrated advanced reservoir simulators

Science.gov (United States)

Darrah, T.; Moortgat, J.; Poreda, R. J.; Muehlenbachs, K.; Whyte, C. J.

2015-12-01

Although hydrocarbon production from unconventional energy resources has increased dramatically in the last decade, total unconventional oil and gas recovery from black shales is still less than 25% and 9% of the totals in place, respectively. Further, the majority of increased hydrocarbon production results from increasing the lengths of laterals, the number of hydraulic fracturing stages, and the volume of consumptive water usage. These strategies all reduce the economic efficiency of hydrocarbon extraction. The poor recovery statistics result from an insufficient understanding of some of the key physical processes in complex, organic-rich, low porosity formations (e.g., phase behavior, fluid-rock interactions, and flow mechanisms at nano-scale confinement and the role of natural fractures and faults as conduits for flow). Noble gases and other hydrocarbon tracers are capably of recording subsurface fluid-rock interactions on a variety of geological scales (micro-, meso-, to macro-scale) and provide analogs for the movement of hydrocarbons in the subsurface. As such geochemical data enrich the input for the numerical modeling of multi-phase (e.g., oil, gas, and brine) fluid flow in highly heterogeneous, low permeability formations Herein we will present a combination of noble gas (He, Ne, Ar, Kr, and Xe abundances and isotope ratios) and molecular and isotopic hydrocarbon data from a geographically and geologically diverse set of unconventional hydrocarbon reservoirs in North America. Specifically, we will include data from the Marcellus, Utica, Barnett, Eagle Ford, formations and the Illinois basin. Our presentation will include geochemical and geological interpretation and our perspective on the first steps toward building an advanced reservoir simulator for tracer transport in multicomponent multiphase compositional flow (presented separately, in Moortgat et al., 2015).

Discrimination of reservoir fluid contacts using compressional and ...

African Journals Online (AJOL)

Improved fluid detection and lithology discrimination using rock properties and attributes cross plots have been attempted using well log data in an Onshore Niger Delta field. Rock properties and attributes were extracted using empirical rock physics models on well logs and used to validate their potentials as pore fluid ...

Rock-fluid chemical interactions at reservoir conditions: The influence of brine chemistry and extent of reaction

Science.gov (United States)

Anabaraonye, B. U.; Crawshaw, J.; Trusler, J. P. M.

2016-12-01

Following carbon dioxide injection in deep saline aquifers, CO2 dissolves in the formation brines forming acidic solutions that can subsequently react with host reservoir minerals, altering both porosity and permeability. The direction and rates of these reactions are influenced by several factors including properties that are associated with the brine system. Consequently, understanding and quantifying the impacts of the chemical and physical properties of the reacting fluids on overall reaction kinetics is fundamental to predicting the fate of the injected CO2. In this work, we present a comprehensive experimental study of the kinetics of carbonate-mineral dissolution in different brine systems including sodium chloride, sodium sulphate and sodium bicarbonate of varying ionic strengths. The impacts of the brine chemistry on rock-fluid chemical reactions at different extent of reactions are also investigated. Using a rotating disk technique, we have investigated the chemical interactions between the CO2-saturated brines and carbonate minerals at conditions of pressure (up to 10 MPa) and temperature (up to 373 K) pertinent to carbon storage. The changes in surface textures due to dissolution reaction were studied by means of optical microscopy and vertical scanning interferometry. Experimental results are compared to previously derived models.

The influence of lumping on the behavior of reservoir with light oil and CO2

Energy Technology Data Exchange (ETDEWEB)

Scanavini, Helena Finardi Alvares [Universidade Estadual de Campinas (UNISIM/UNICAMP), SP (Brazil). Dept. de Engenharia de Petroleo. Pesquisa em Simulacao e Gerenciamento de Reservatorios; Schiozer, Denis Jose [Universidade Estadual de Campinas (DEP/FEM/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Engenharia de Petroleo

2012-07-01

Compositional simulation demands a large number of equations and functions to be solved, once fluid properties depend on reservoir pressure and temperature and also on fluid composition. As a consequence, the number of components used influences considerably in the simulation run time and accuracy: more components yield more equations to be solved with expected higher run time. Giant petroleum fields discovered recently in Brazil (pre-salt reservoirs) demand compositional simulation due to the fluid characteristics (light oil with the presence of CO2). However, the computational time can be a limitation because of the number of grid blocks that are necessary to represent the reservoir. So, reducing the number of components is an important step for the simulation models. Under this context, this paper presents a study on the influence of different lumping clusters, used to reduce the number of components in a volatile oil, on reservoir simulation. Phase diagram, saturation pressure and simulation results were used for comparison purposes. The best results were obtained for the cases with 14, 9 and 7 pseudo components, which represented correctly the original fluid, reducing till three times the simulation run time, for the same production volumes of oil and gas. (author)

Orthodontic Tooth Movement: A Historic Prospective.

Science.gov (United States)

Will, Leslie A

2016-01-01

The earliest report on orthodontic tooth movement in the English literature was published in 1911. Oppenheim carried out studies on baboons to determine what histologic changes occurred during tooth movement. Reitan and many others carried out research into the nature of tooth movement. The pressure-tension model of tooth movement developed from these studies, whereby the two sides of the tooth responded to forces as if in isolation. A second theory, proposed by Stuteville in 1938, was the hydraulic theory of tooth movement. In this theory, fluid from the vasculature, lymphatic system and intercellular spaces responds to the forces of tooth movement, damping the force and limiting movement. Bien and Baumrind expanded on this theory with their own studies in the 1960s. It is clear that both the pressure-tension and fluid flow concepts have merit, but considerable work needs to be done to ascertain the details so that tooth movement can be managed and controlled. © 2016 S. Karger AG, Basel.

Analysis of birth-death fluid queues

NARCIS (Netherlands)

van Doorn, Erik A.; Scheinhardt, Willem R.W.

1996-01-01

We present a survey of techniques for analysing the performance of a reservoir which receives and releases fluid at rates which are determined by the state of a background birth-death process. The reservoir is assumed to be infinitely large, but the state space of the modulating birth-death process

An adaptive nonlinear solution scheme for reservoir simulation

Energy Technology Data Exchange (ETDEWEB)

Lett, G.S. [Scientific Software - Intercomp, Inc., Denver, CO (United States)

1996-12-31

Numerical reservoir simulation involves solving large, nonlinear systems of PDE with strongly discontinuous coefficients. Because of the large demands on computer memory and CPU, most users must perform simulations on very coarse grids. The average properties of the fluids and rocks must be estimated on these grids. These coarse grid {open_quotes}effective{close_quotes} properties are costly to determine, and risky to use, since their optimal values depend on the fluid flow being simulated. Thus, they must be found by trial-and-error techniques, and the more coarse the grid, the poorer the results. This paper describes a numerical reservoir simulator which accepts fine scale properties and automatically generates multiple levels of coarse grid rock and fluid properties. The fine grid properties and the coarse grid simulation results are used to estimate discretization errors with multilevel error expansions. These expansions are local, and identify areas requiring local grid refinement. These refinements are added adoptively by the simulator, and the resulting composite grid equations are solved by a nonlinear Fast Adaptive Composite (FAC) Grid method, with a damped Newton algorithm being used on each local grid. The nonsymmetric linear system of equations resulting from Newton`s method are in turn solved by a preconditioned Conjugate Gradients-like algorithm. The scheme is demonstrated by performing fine and coarse grid simulations of several multiphase reservoirs from around the world.

Measuring fluid pressure

International Nuclear Information System (INIS)

Lee, A.S.

1978-01-01

A method and apparatus are described for measuring the pressure of a fluid having characteristics that make it unsuitable for connection directly to a pressure gauge. The method is particularly suitable for the periodic measurement of the pressure of a supply of liquid Na to Na-lubricated bearings of pumps for pumping Na from a reservoir to the bearing via a filter, the reservoir being contained in a closed vessel containing an inert blanket gas, such as Ar, above the Na. (UK)

Scale Model Simulation of Enhanced Geothermal Reservoir Creation

Science.gov (United States)

Gutierrez, M.; Frash, L.; Hampton, J.

2012-12-01

Geothermal energy technology has successfully provided a means of generating stable base load electricity for many years. However, implementation has been spatially limited to limited availability of high quality traditional hydro-thermal resources possessing the combination of a shallow high heat flow anomaly and an aquifer with sufficient permeability and continuous fluid recharge. Enhanced Geothermal Systems (EGS) has been proposed as a potential solution to enable additional energy production from the non-conventional hydro-thermal resources. Hydraulic fracturing is considered the primary means of creating functional EGS reservoirs at sites where the permeability of the rock is too limited to allow cost effective heat recovery. EGS reservoir creation requires improved fracturing methodology, rheologically controllable fracturing fluids, and temperature hardened proppants. Although large fracture volumes (several cubic km) have been created in the field, circulating fluid through these full volumes and maintaining fracture volumes have proven difficult. Stimulation technology and methodology as used in the oil and gas industry for sedimentary formations are well developed; however, they have not sufficiently been demonstrated for EGS reservoir creation. Insufficient data and measurements under geothermal conditions make it difficult to directly translate experience from the oil and gas industries to EGS applications. To demonstrate the feasibility of EGS reservoir creation and subsequent geothermal energy production, and to improve the understanding of hydraulic and propping in EGS reservoirs, a heated true-triaxial load cell with a high pressure fluid injection system was developed to simulate an EGS system from stimulation to production. This apparatus is capable of loading a 30x30x30 cubic cm rock sample with independent principal stresses up to 13 MPa while simultaneously providing heating up to 180 degree C. Multiple orientated boreholes of 5 to 10 mm

Analysis of birth-death fluid queues

OpenAIRE

van Doorn, Erik A.; Scheinhardt, Willem R.W.

1996-01-01

We present a survey of techniques for analysing the performance of a reservoir which receives and releases fluid at rates which are determined by the state of a background birth-death process. The reservoir is assumed to be infinitely large, but the state space of the modulating birth-death process may be finite or infinite.

Naturally fractured reservoirs-yet an unsolved mystery

International Nuclear Information System (INIS)

Zahoor, M.K.

2013-01-01

Some of the world's most profitable reservoirs are assumed to be naturally fractured reservoirs (NFR). Effective evaluation, prediction and planning of these reservoirs require an early recognition of the role of natural fractures and then a comprehensive study of factors which affect the flowing performance through these fractures is necessary. As NFRs are the combination of matrix and fractures mediums so their analysis varies from non-fractured reservoirs. Matrix acts as a storage medium while mostly fluid flow takes place from fracture network. Many authors adopted different approaches to understand the flow behavior in such reservoirs. In this paper a broad review about the previous work done in naturally fractured reservoirs area is outlined and a different idea is initiated for the NFR simulation studies. The role of capillary pressure in natural fractures is always been a key factor for accurate recovery estimations. Also recovery through these reservoirs is dependent upon grid block shape while doing NFR simulation. Some authors studied above mentioned factors in combination with other rock properties to understand the flow behavior in such reservoirs but less emphasis was given for checking the effects on recovery estimations by the variations of only fracture capillary pressures and grid block shapes. So there is need to analyze the behavior of NFR for the mentioned conditions. (author)

Quantifying the clay content with borehole depth and impact on reservoir flow

Science.gov (United States)

Sarath Kumar, Aaraellu D.; Chattopadhyay, Pallavi B.

2017-04-01

This study focuses on the application of reservoir well log data and 3D transient numerical model for proper optimization of flow dynamics and hydrocarbon potential. Fluid flow through porous media depends on clay content that controls porosity, permeability and pore pressure. The pressure dependence of permeability is more pronounced in tight formations. Therefore, preliminary clay concentration analysis and geo-mechanical characterizations have been done by using wells logs. The assumption of a constant permeability for a reservoir is inappropriate and therefore the study deals with impact of permeability variation for pressure-sensitive formation. The study started with obtaining field data from available well logs. Then, the mathematical models are developed to understand the efficient extraction of oil in terms of reservoir architecture, porosity and permeability. The fluid flow simulations have been done using COMSOL Multiphysics Software by choosing time dependent subsurface flow module that is governed by Darcy's law. This study suggests that the reservoir should not be treated as a single homogeneous structure with unique porosity and permeability. The reservoir parameters change with varying clay content and it should be considered for effective planning and extraction of oil. There is an optimum drawdown for maximum production with varying permeability in a reservoir.

Reservoir souring: it is all about risk mitigation

Energy Technology Data Exchange (ETDEWEB)

Kuijvenhoven, Cor [Shell (Canada)

2011-07-01

The presence of H2S in produced fluid can be due to various sources, among which are heat/rock interaction and leaks from other reservoirs. This paper discusses the reasons, risk assessment and tools for mitigating reservoir souring. Uncontrolled microorganism activity can cause a sweet reservoir (without H2S) to become sour (production of H2S). The development of bacteria is one of the main causes of reservoir souring in unconventional gas fields. It is difficult to predict souring in seawater due to produced water re-injection (PWRI). Risk assessment and modeling techniques for reservoir souring are discussed. Some of the factors controlling H2S production include injection location, presence of scavenging minerals and biogenic souring. Mitigation methods such as biocide treatment of injection water, sulphate removal from seawater, microbial monitoring techniques such as the molecular microbiology method (MMM), and enumeration by serial dilution are explained. In summary, it can be concluded that reservoir souring is a long-term problem and should be assessed at the beginning of operations.

Optimized CO{sub 2} miscible hydrocarbon fracturing fluids

Energy Technology Data Exchange (ETDEWEB)

Taylor, R.S.; Funkhouser, G.P.; Fyten, G.; Attaway, D.; Watkins, H. [Halliburton Energy Services, Calgary, AB (Canada); Lestz, R.S. [Chevron Canada Resources, Calgary, AB (Canada); Loree, D. [FracEx Inc. (Canada)

2006-07-01

Carbon dioxide (CO{sub 2}) miscible hydrocarbon fracturing fluids address issues of fluid retention in low-permeability gas reservoirs, including undersaturated and underpressured reservoirs. An optimized surfactant gel technology using carbon dioxide (CO{sub 2}) hydrocarbon fracturing fluids applicable to all gas-well stimulation applications was discussed in this paper. The crosslinked surfactant gel technology improved proppant transport, leakoff control, and generation of effective fracture half-length. Tests indicated that application of the surfactant cooled the fracture face, which had the effect of extending break times and increasing viscosity during pumping periods. Rapid recovery of the fracturing fluid eliminated the need for swabbing in some cases, and the fluid system was not adversely affected by shear. However, rheological test equipment capable of mixing liquid CO{sub 2} and viscosified hydrocarbons at downhole temperatures is required to determine rheology and required chemical concentrations. It was recommended that to achieve an effective methane-drive cleanup mechanism, treatments should be designed so that the gellant system can be effective with up to 50 per cent CO{sub 2} dissolved in oil. It was concluded that it should be possible to apply the technology to low permeability gas reservoirs. Viscosity curves and friction data were presented. Issues concerning the selection of tubulars and flowback procedures were also discussed. It was suggested that the cost of the hydrocarbon fracturing fluid can be recovered by the sale of recovered load fluid. 6 refs., 4 figs.

Fluids in crustal deformation: Fluid flow, fluid-rock interactions, rheology, melting and resources

Science.gov (United States)

Lacombe, Olivier; Rolland, Yann

2016-11-01

Fluids exert a first-order control on the structural, petrological and rheological evolution of the continental crust. Fluids interact with rocks from the earliest stages of sedimentation and diagenesis in basins until these rocks are deformed and/or buried and metamorphosed in orogens, then possibly exhumed. Fluid-rock interactions lead to the evolution of rock physical properties and rock strength. Fractures and faults are preferred pathways for fluids, and in turn physical and chemical interactions between fluid flow and tectonic structures, such as fault zones, strongly influence the mechanical behaviour of the crust at different space and time scales. Fluid (over)pressure is associated with a variety of geological phenomena, such as seismic cycle in various P-T conditions, hydrofracturing (including formation of sub-horizontal, bedding-parallel veins), fault (re)activation or gravitational sliding of rocks, among others. Fluid (over)pressure is a governing factor for the evolution of permeability and porosity of rocks and controls the generation, maturation and migration of economic fluids like hydrocarbons or ore forming hydrothermal fluids, and is therefore a key parameter in reservoir studies and basin modeling. Fluids may also help the crust partially melt, and in turn the resulting melt may dramatically change the rheology of the crust.

Carbon dioxide sequestration induced mineral precipitation healing of fractured reservoir seals

Science.gov (United States)

Welch, N.; Crawshaw, J.

2017-12-01

Initial experiments and the thermodynaic basis for carbon dioxide sequestration induced mineral precipitation healing of fractures through reservoir seals will be presented. The basis of this work is the potential exists for the dissolution of reservoir host rock formation carbonate minerals in the acidified injection front of CO2 during sequestration or EOR. This enriched brine and the bulk CO2 phase will then flow through the reservoir until contact with the reservoir seal. At this point any fractures present in the reservoir seal will be the preferential flow path for the bulk CO2 phase as well as the acidified brine front. These fractures would currently be filled with non-acidified brine saturated in seal formation brine. When the acidifeid brine from the host formation and the cap rock brine mix there is the potential for minerals to fall out of solution, and for these precipitated minerals to decrease or entirely cut off the fluid flow through the fractures present in a reservoir seal. Initial equilibrium simulations performed using the PHREEQC1 database drived from the PHREEQE2 database are used to show the favorable conditions under which this mineral precipitation can occurs. Bench scale fluid mixing experiments were then performed to determine the kinetics of the mineral precipitation process, and determine the progress of future experiemnts involving fluid flow within fractured anhydrite reservoir seal samples. 1Parkhurst, D.L., and Appelo, C.A.J., 2013, Description of input and examples for PHREEQC version 3—A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations: U.S. Geological Survey Techniques and Methods, book 6, chap. A43, 497 p., available only at https://pubs.usgs.gov/tm/06/a43/. 2Parkhurst, David L., Donald C. Thorstenson, and L. Niel Plummer. PHREEQE: a computer program for geochemical calculations. No. 80-96. US Geological Survey, Water Resources Division,, 1980.

Geological model of supercritical geothermal reservoir related to subduction system

Science.gov (United States)

Tsuchiya, Noriyoshi

2017-04-01

Following the Great East Japan Earthquake and the accident at the Fukushima Daiichi Nuclear power station on 3.11 (11th March) 2011, geothermal energy came to be considered one of the most promising sources of renewable energy for the future in Japan. The temperatures of geothermal fields operating in Japan range from 200 to 300 °C (average 250 °C), and the depths range from 1000 to 2000 m (average 1500 m). In conventional geothermal reservoirs, the mechanical behavior of the rocks is presumed to be brittle, and convection of the hydrothermal fluid through existing network is the main method of circulation in the reservoir. In order to minimize induced seismicity, a rock mass that is "beyond brittle" is one possible candidate, because the rock mechanics of "beyond brittle" material is one of plastic deformation rather than brittle failure. Supercritical geothermal resources could be evaluated in terms of present volcanic activities, thermal structure, dimension of hydrothermal circulation, properties of fracture system, depth of heat source, depth of brittle factures zone, dimension of geothermal reservoir. On the basis of the GIS, potential of supercritical geothermal resources could be characterized into the following four categories. 1. Promising: surface manifestation d shallow high temperature, 2 Probability: high geothermal gradient, 3 Possibility: Aseismic zone which indicates an existence of melt, 4 Potential : low velocity zone which indicates magma input. Base on geophysical data for geothermal reservoirs, we have propose adequate tectonic model of development of the supercritical geothermal reservoirs. To understand the geological model of a supercritical geothermal reservoir, granite-porphyry system, which had been formed in subduction zone, was investigated as a natural analog of the supercritical geothermal energy system. Quartz veins, hydrothermal breccia veins, and glassy veins are observed in a granitic body. The glassy veins formed at 500-550 �

pressure analysis and fluid contact prediction for alpha reservoir

African Journals Online (AJOL)

HOD

a pressure gradient profile such that the oil gradient line will intersect the hydrostatic line above the Water-Up-To. (WUT) line to define the OWC if present. The model was also calibrated with data from reservoirs with established contacts in the field. 3. RESULTS AND DISCUSSION. In the field, pressure typically increases ...

Tidal phenomena in reservoirs; Fenomeno de mare em reservatorios

Energy Technology Data Exchange (ETDEWEB)

Pinilla Cortes, John Freddy

1997-06-01

This work models the oceanic tidal effect on reservoirs by coupling geomechanic principles with equations for fluid in a deformable porous media. The coupling revealed the importance of establishing properly the system compressibility under the various possible configurations of the loading system. The basic models for infinite reservoir, constant outer-pressure reservoir and closed reservoir were considered. It was verified that it was possible to apply the superposition of effects on the solution for the basic models by carrying a simple transformation on the solution variable. The problem was treated by in the context of test analysis, concerning dimensionless form of variables and the inclusion of well effects. The solution for the infinite reservoir including tidal effects. The solution for the infinite reservoir including tidal effects was obtained in the Laplace space and was inverted numerically by using Crump's routine. The results were incorporated to conventional type curves, and were validated by comparison with real and simulated pressure test data. Finally, alternate practices were suggested to integrate the well test analysis in reservoirs affected by the tidal effect. (author)

Numerical modeling of shear stimulation in naturally fractured geothermal reservoirs

OpenAIRE

Ucar, Eren

2018-01-01

Shear-dilation-based hydraulic stimulations are conducted to create enhanced geothermal systems (EGS) from low permeable geothermal reservoirs, which are initially not amenable to energy production. Reservoir stimulations are done by injecting low-pressurized fluid into the naturally fractured formations. The injection aims to activate critically stressed fractures by decreasing frictional strength and ultimately cause a shear failure. The shear failure leads to a permanent ...

Petrofacies analysis - the petrophysical tool for geologic/engineering reservoir characterization

Energy Technology Data Exchange (ETDEWEB)

Watney, W.L.; Guy, W.J.; Gerlach, P.M. [Kansas Geological Survey, Lawrence, KS (United States)] [and others

1997-08-01

Petrofacies analysis is defined as the characterization and classification of pore types and fluid saturations as revealed by petrophysical measures of a reservoir. The word {open_quotes}petrofacies{close_quotes} makes an explicit link between petroleum engineers concerns with pore characteristics as arbiters of production performance, and the facies paradigm of geologists as a methodology for genetic understanding and prediction. In petrofacies analysis, the porosity and resistivity axes of the classical Pickett plot are used to map water saturation, bulk volume water, and estimated permeability, as well as capillary pressure information, where it is available. When data points are connected in order of depth within a reservoir, the characteristic patterns reflect reservoir rock character and its interplay with the hydrocarbon column. A third variable can be presented at each point on the crossplot by assigning a color scale that is based on other well logs, often gamma ray or photoelectric effect, or other derived variables. Contrasts between reservoir pore types and fluid saturations will be reflected in changing patterns on the crossplot and can help discriminate and characterize reservoir heterogeneity. Many hundreds of analyses of well logs facilitated by spreadsheet and object-oriented programming have provided the means to distinguish patterns typical of certain complex pore types for sandstones and carbonate reservoirs, occurrences of irreducible water saturation, and presence of transition zones. The result has been an improved means to evaluate potential production such as bypassed pay behind pipe and in old exploration holes, or to assess zonation and continuity of the reservoir. Petrofacies analysis is applied in this example to distinguishing flow units including discrimination of pore type as assessment of reservoir conformance and continuity. The analysis is facilitated through the use of color cross sections and cluster analysis.

Hydraulically amplified PZT mems actuator

Science.gov (United States)

Miles, Robin R.

2004-11-02

A hydraulically amplified microelectromechanical systems actuator. A piece of piezoelectric material or stacked piezo bimorph is bonded or deposited as a thin film. The piece is operatively connected to a primary membrane. A reservoir is operatively connected to the primary membrane. The reservoir contains a fluid. A membrane is operatively connected to the reservoir. In operation, energizing the piezoelectric material causing the piezoelectric material to bow. Bowing of the piezoelectric material causes movement of the primary membrane. Movement of the primary membrane results in a force in being transmitted to the liquid in the reservoir. The force in the liquid causes movement of the membrane. Movement of the membrane results in an operating actuator.

New geomechanical developments for reservoir management; Desenvolvimentos experimentais e computacionais para analises geomecanicas de reservatorio

Energy Technology Data Exchange (ETDEWEB)

Soares, Antonio C.; Menezes Filho, Armando Prestes; Silvestre, Jose R. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

2008-07-01

The common assumption that oil is produced under a constant rate only considering reservoir depletion has been questioned for some time. An usual hypothesis is that the physical properties of a reservoir are not constants during time, but they vary according to the properties of reservoir rock and the characteristics of the external loads. More precisely, as soon as a reservoir is explored, the volume of fluid diminishes, decreasing the static pressure and increasing the effective stress over the rock skeleton, which, depending on the nature of rock, can lead to a gradual deformation and alteration of reservoir's porosity and permeability, and oil productivity as well. This paper aims at showing numerical and experimental achievements, developed by the Well bore Engineering Technology Department of CENPES, devoted to the characterization of the influence of stress-strain states on the permeability and production of reservoir rocks. It is believed that these developments can possibly bring some light to the understanding of this complex phenomenon, besides allowing the establishment of more realistic relations involving stress-strain-permeability in coupled fluid dynamic problems. (author)

Ray-based stochastic inversion of pre-stack seismic data for improved reservoir characterisation

NARCIS (Netherlands)

van der Burg, D.W.

2007-01-01

To estimate rock and pore-fluid properties of oil and gas reservoirs in the subsurface, techniques can be used that invert seismic data. Hereby, the detailed information about the reservoir that is available at well locations, such as the thickness and porosity of individual layers, is extrapolated

Alteration of fault rocks by CO2-bearing fluids with implications for sequestration

Science.gov (United States)

Luetkemeyer, P. B.; Kirschner, D. L.; Solum, J. G.; Naruk, S.

2011-12-01

Carbonates and sulfates commonly occur as primary (diagenetic) pore cements and secondary fluid-mobilized veins within fault zones. Stable isotope analyses of calcite, formation fluid, and fault zone fluids can help elucidate the carbon sources and the extent of fluid-rock interaction within a particular reservoir. Introduction of CO2 bearing fluids into a reservoir/fault system can profoundly affect the overall fluid chemistry of the reservoir/fault system and may lead to the enhancement or degradation of porosity within the fault zone. The extent of precipitation and/or dissolution of minerals within a fault zone can ultimately influence the sealing properties of a fault. The Colorado Plateau contains a number of large carbon dioxide reservoirs some of which leak and some of which do not. Several normal faults within the Paradox Basin (SE Utah) dissect the Green River anticline giving rise to a series of footwall reservoirs with fault-dependent columns. Numerous CO2-charged springs and geysers are associated with these faults. This study seeks to identify regional sources and subsurface migration of CO2 to these reservoirs and the effect(s) faults have on trap performance. Data provided in this study include mineralogical, elemental, and stable isotope data for fault rocks, host rocks, and carbonate veins that come from two localities along one fault that locally sealed CO2. This fault is just tens of meters away from another normal fault that has leaked CO2-charged waters to the land surface for thousands of years. These analyses have been used to determine the source of carbon isotopes from sedimentary derived carbon and deeply sourced CO2. XRF and XRD data taken from several transects across the normal faults are consistent with mechanical mixing and fluid-assisted mass transfer processes within the fault zone. δ13C range from -6% to +10% (PDB); δ18O values range from +15% to +24% (VSMOW). Geochemical modeling software is used to model the alteration

Study on the enhancement of hydrocarbon recovery by characterization of the reservoir

Energy Technology Data Exchange (ETDEWEB)

Kwak, Young Hoon; Son, Jin Dam; Oh, Jae Ho [Korea Institute of Geology Mining and Materials, Taejon (Korea)] [and others

1998-12-01

Three year project is being carried out on the enhancement of hydrocarbon recovery by the reservoir characterization. This report describes the results of the second year's work. This project deals with characterization of fluids, bitumen ad rock matrix in the reservoir. New equipment and analytical solutions for naturally fractured reservoir were also included in this study. Main purpose of the reservoir geochemistry is to understand the origin of fluids (gas, petroleum and water) and distribution of the bitumens within the reservoir and to use them not only for exploration but development of the petroleum. For the theme of reservoir geochemistry, methods and principles of the reservoir gas and bitumen characterization, which is applicable to the petroleum development, are studied. and case study was carried out on the gas, water and bitumen samples in the reservoir taken form Haenam area and Ulleung Basin offshore Korea. Gases taken form the two different wells indicate the different origin. Formation water analyses show the absence of barrier within the tested interval. With the sidewall core samples from a well offshore Korea, the analysis using polarizing microscope, scanning electron microscope with EDX and cathodoluminoscope was performed for the study on sandstone diagenesis. The I/S changes were examined on the cuttings samples from a well, offshore Korea to estimate burial temperature. Oxygen stable isotope is used to study geothermal history in sedimentary basin. Study in the field is rare in Korea and basic data are urgently needed especially in continental basins to determine the value of formation water. In the test analyses, three samples from marine basins indicate final temperature from 55 deg.C to 83 deg.C and one marine sample indicate the initial temperature of 36 deg.C. One sample from continental basin represented the final temperature from 53 and 80 deg.C. These temperatures will be corrected because these values were based on assumed

CO2/ brine substitution experiments at simulated reservoir conditions

Science.gov (United States)

Kummerow, Juliane; Spangenberg, Erik

2015-04-01

Capillary properties of rocks affect the mobility of fluids in a reservoir. Therefore, the understanding of the capillary pressure behaviour is essential to assess the long-term behaviour of CO2 reservoirs. Beyond this, a calibration of the petrophysical properties on water saturation of reservoir rocks at simulated in situ conditions is crucial for a proper interpretation of field monitoring data. We present a set-up, which allows for the combined measurements of capillary pressure, electric resistivity, and elastic wave velocities under controlled reservoir conditions (pconf = 400 bar, ppore = 180 bar, T = 65 ° C) at different brine-CO2 saturations. The capillary properties of the samples are measured using the micropore membrane technique. The sample is jacketed with a Viton tube (thickness = 4 mm) and placed between two current electrode endcaps, which as well contain pore fluid ports and ultrasonic P and S wave transducers. Between the sample and the lower endcap the hydrophilic semi-permeable micro-pore membrane (pore size = 100 nm) is integrated. It is embedded into filter papers to establish a good capillary contact and to protect the highly sensitive membrane against mechanical damage under load. Two high-precision syringe pumps are used to displace a quantified volume of brine by CO2 and determine the corresponding sample saturation. The fluid displacement induces a pressure gradient along the sample, which corresponds to the capillary pressure at a particular sample saturation. It is measured with a differential pressure sensor in the range between 0 - 0.2 MPa. Drainage and imbibition cycles are performed to provide information on the efficiency of capillary trapping and to get a calibration of the petrophysical parameters of the sample.

Using reservoir engineering data to solve geological ambiguities : a case study of one of the Iranian carbonate reservoirs

Energy Technology Data Exchange (ETDEWEB)

Kord, S. [National Iranian South Oil Co. (Iran, Islamic Republic of)

2006-07-01

A fractured carbonate reservoir in southwest Iran was studied with reference to reserve estimation, risk analysis, material balance and recovery factor. The 40 km long and 4 km wide reservoir consists of 2 parts with crest depths of 3780 and 3749 mss respectively. The eastern part is smaller and more productive than the western part which has high water saturation and absolutely no production. Economic production from the reservoir began in 1977. By 2004, the cumulative production had reached 12.064 MMSTB. Of the 6 wells drilled, only 2 wells in the eastern part are productive. This study addressed the main uncertainty of whether the 2 parts of the reservoir are sealed or not. The reservoir is under-saturated but the current pressure is near saturation pressure. The reservoir is divided into the following 4 zones: zones 1 and 2 are productive and consist mainly of carbonate rocks; zone 3 has thin beds of sand and shale; and, zone 4 consists of layers of carbonate, shale, marn, and dolomite. Although there are no faults, mud loss suggests that the reservoir has hairline fractures. Oil in place and reserves were estimated for both parts based on calculated reservoir engineering parameters. Material balance calculations were then performed to analyze and simulate the reservoir. The communication between the 2 parts of the reservoir were examined according to core analysis, rock type, fluid characterization, pressure analysis, water-oil contacts, production history and petrophysical evaluations. The porosity was found to be the same in both parts, but the water saturation and net to gross ratios were different between the eastern and western parts. The petrophysical evaluation revealed that there is no communication between the two parts of the reservoir. 4 refs., 2 figs., 2 appendices.

Reservoir Changes Derived from Seismic Observations at The Geysers Geothermal Field, CA, USA

Science.gov (United States)

Gritto, R.; Jarpre, S.

2012-04-01

Induced seismicity associated with the exploitation of geothermal fields is used as a tool to characterize and delineate changes associated with injection and production of fluids from the reservoir. At the same time public concern of felt seismicity has led to objections against the operation of geothermal reservoirs in close proximity to population centers. Production at the EGS sites in Basel (Switzerland) was stopped after renewed seismicity caused concern and objection from the public in the city. Operations in other geothermal reservoirs had to be scaled back or interrupted due to an unexpected increase in seismicity (Soultz-sous-forêt, France, Berlín, El Salvador). As a consequence of these concerns and in order to optimize the use of induced seismicity for reservoir engineering purposes, it becomes imperative to understand the relationship between seismic events and stress changes in the reservoir. We will address seismicity trends at The Geysers Geothermal Reservoir, CA USA, to understand the role of historical seismicity associated with past injection of water and/or production of steam. Our analysis makes use of a comprehensive database of earthquakes and associated phase arrivals from 2004 to 2011. A high-precision sub-set of the earthquake data was selected to analyze temporal changes in seismic velocities and Vp/Vs-ratio throughout the whole reservoir. We find relatively low Vp/Vs values in 2004 suggestive of a vapor dominated reservoir. With passing time, however, the observed temporal increase in Vp/Vs, coupled with a decrease in P- and S-wave velocities suggests the presence of fluid-filled fractured rock. Considering the start of a continuous water injection project in 2004, it can be concluded that the fluid saturation of the reservoir has successfully recovered. Preliminary results of 3-D velocity inversions of seismic data appear to corroborate earlier findings that the lowest Vp/Vs estimates are observed in the center of the reservoir

Rate of Change in Lake Level and its Impact on Reservoir-triggered Seismicity

Science.gov (United States)

Simpson, D. W.

2017-12-01

With recent interest in increased seismicity related to fluid injection, it is useful to review cases of reservoir-triggered earthquakes to explore common characteristics and seek ways to mitigate the influence of anthropogenic impacts. Three reservoirs - Koyna, India; Nurek, Tajikistan; and Aswan, Egypt - are well-documented cases of triggered earthquakes with recorded time series of seismicity and water levels that extend for more than 30 years. The geological setting, regional tectonics and modes of reservoir utilization, along with the characteristics of the reservoir-seismicity interaction, are distinctly different in each of these three cases. Similarities and differences between these three cases point to regional and local geological and hydrological structures and the rate of changes in reservoir water level as important factors controlling the presence and timing of triggered seismicity. In a manner similar to the way in which the rate of fluid injection influences injection-related seismicity, the rate of change in reservoir water level is a significant factor in determining whether or not reservoir-triggered seismicity occurs. The high rate of annual water level rise may be important in sustaining the exceptionally long sequence of earthquakes at Koyna. In addition to the rate of filling being a determining factor in whether or not earthquakes are triggered, changes in the rate of filling may influence the time of occurrence of individual earthquakes.

Application of Reservoir Flow Simulation Integrated with Geomechanics in Unconventional Tight Play

Science.gov (United States)

Lin, Menglu; Chen, Shengnan; Mbia, Ernest; Chen, Zhangxing

2018-01-01

Multistage hydraulic fracturing techniques, combined with horizontal drilling, have enabled commercial production from the vast reserves of unconventional tight formations. During hydraulic fracturing, fracturing fluid and proppants are pumped into the reservoir matrix to create the hydraulic fractures. Understanding the propagation mechanism of hydraulic fractures is essential to estimate their properties, such as half-length. In addition, natural fractures are often present in tight formations, which might be activated during the fracturing process and contribute to the post-stimulation well production rates. In this study, reservoir simulation is integrated with rock geomechanics to predict the well post-stimulation productivities. Firstly, a reservoir geological model is built based on the field data collected from the Montney formation in the Western Canadian Sedimentary Basin. The hydraulic fracturing process is then simulated through an integrated approach of fracturing fluid injection, rock geomechanics, and tensile failure criteria. In such a process, the reservoir pore pressure increases with a continuous injection of the fracturing fluid and proppants, decreasing the effective stress exerted on the rock matrix accordingly as the overburden pressure remains constant. Once the effective stress drops to a threshold value, tensile failure of the reservoir rock occurs, creating hydraulic fractures in the formation. The early production history of the stimulated well is history-matched to validate the predicted fracture geometries (e.g., half-length) generated from the fracturing simulation process. The effects of the natural fracture properties and well bottom-hole pressures on well productivity are also studied. It has been found that nearly 40% of hydraulic fractures propagate in the beginning stage (the pad step) of the fracturing schedule. In addition, well post-stimulation productivity will increase significantly if the natural fractures are propped or

Advances in coalbed methane reservoirs using integrated reservoir characterization and hydraulic fracturing in Karaganda coal basin, Kazakhstan

Science.gov (United States)

Ivakhnenko, Aleksandr; Aimukhan, Adina; Kenshimova, Aida; Mullagaliyev, Fandus; Akbarov, Erlan; Mullagaliyeva, Lylia; Kabirova, Svetlana; Almukhametov, Azamat

2017-04-01

Coalbed methane from Karaganda coal basin is considered to be an unconventional source of energy for the Central and Eastern parts of Kazakhstan. These regions are situated far away from the main traditional sources of oil and gas related to Precaspian petroleum basin. Coalbed methane fields in Karaganda coal basin are characterized by geological and structural complexity. Majority of production zones were characterized by high methane content and extremely low coal permeability. The coal reservoirs also contained a considerable natural system of primary, secondary, and tertiary fractures that were usually capable to accommodate passing fluid during hydraulic fracturing process. However, after closing was often observed coal formation damage including the loss of fluids, migration of fines and higher pressures required to treat formation than were expected. Unusual or less expected reservoir characteristics and values of properties of the coal reservoir might be the cause of the unusual occurred patterns in obtained fracturing, such as lithological peculiarities, rock mechanical properties and previous natural fracture systems in the coals. Based on these properties we found that during the drilling and fracturing of the coal-induced fractures have great sensitivity to complex reservoir lithology and stress profiles, as well as changes of those stresses. In order to have a successful program of hydraulic fracturing and avoid unnecessary fracturing anomalies we applied integrated reservoir characterization to monitor key parameters. In addition to logging data, core sample analysis was applied for coalbed methane reservoirs to observe dependence tiny lithological variations through the magnetic susceptibility values and their relation to permeability together with expected principal stress. The values of magnetic susceptibility were measured by the core logging sensor, which is equipped with the probe that provides volume magnetic susceptibility parameters

Reflection Phenomena in Underground Pumped Storage Reservoirs

Directory of Open Access Journals (Sweden)

Elena Pummer

2018-04-01

Full Text Available Energy storage through hydropower leads to free surface water waves in the connected reservoirs. The reason for this is the movement of water between reservoirs at different elevations, which is necessary for electrical energy storage. Currently, the expansion of renewable energies requires the development of fast and flexible energy storage systems, of which classical pumped storage plants are the only technically proven and cost-effective technology and are the most used. Instead of classical pumped storage plants, where reservoirs are located on the surface, underground pumped storage plants with subsurface reservoirs could be an alternative. They are independent of topography and have a low surface area requirement. This can be a great advantage for energy storage expansion in case of environmental issues, residents’ concerns and an unusable terrain surface. However, the reservoirs of underground pumped storage plants differ in design from classical ones for stability and space reasons. The hydraulic design is essential to ensure their satisfactory hydraulic performance. The paper presents a hybrid model study, which is defined here as a combination of physical and numerical modelling to use the advantages and to compensate for the disadvantages of the respective methods. It shows the analysis of waves in ventilated underground reservoir systems with a great length to height ratio, considering new operational aspects from energy supply systems with a great percentage of renewable energies. The multifaceted and narrow design of the reservoirs leads to complex free surface flows; for example, undular and breaking bores arise. The results show excessive wave heights through wave reflections, caused by the impermeable reservoir boundaries. Hence, their knowledge is essential for a successful operational and constructive design of the reservoirs.

Gravity Effect on Two-Phase Immiscible Flows in Communicating Layered Reservoirs

DEFF Research Database (Denmark)

Zhang, Xuan; Shapiro, Alexander; Stenby, Erling Halfdan

2012-01-01

An upscaling method is developed for two-phase immiscible incompressible flows in layered reservoirs with good communication between the layers. It takes the effect of gravity into consideration. Waterflooding of petroleum reservoirs is used as a basic example for application of this method....... An asymptotic analysis is applied to a system of 2D flow equations for incompressible fluids at high-anisotropy ratios, but low to moderate gravity ratios, which corresponds to the most often found reservoir conditions. The 2D Buckley–Leverett problem is reduced to a system of 1D parabolic equations...

Molecular Simulation towards Efficient and Representative Subsurface Reservoirs Modeling

KAUST Repository

Kadoura, Ahmad Salim

2016-01-01

This dissertation focuses on the application of Monte Carlo (MC) molecular simulation and Molecular Dynamics (MD) in modeling thermodynamics and flow of subsurface reservoir fluids. At first, MC molecular simulation is proposed as a promising method

Cased-hole log analysis and reservoir performance monitoring

CERN Document Server

Bateman, Richard M

2015-01-01

This book addresses vital issues, such as the evaluation of shale gas reservoirs and their production. Topics include the cased-hole logging environment, reservoir fluid properties; flow regimes; temperature, noise, cement bond, and pulsed neutron logging; and casing inspection. Production logging charts and tables are included in the appendices. The work serves as a comprehensive reference for production engineers with upstream E&P companies, well logging service company employees, university students, and petroleum industry training professionals. This book also: ·       Provides methods of conveying production logging tools along horizontal well segments as well as measurements of formation electrical resistivity through casing ·       Covers new information on fluid flow characteristics in inclined pipe and provides new and improved nuclear tool measurements in cased wells ·       Includes updates on cased-hole wireline formation testing  

Reservoir Souring - Latest developments for application and mitigation

DEFF Research Database (Denmark)

Johnson, Richard J; Folwell, Benjamin D; Wirekoh, Alexander

2017-01-01

Sulphate-reducing prokaryotes (SRP) have been identified in oil field fluids since the 1920s. SRP reduce sulphate to sulphide, a toxic and corrosive species that impacts on operational safety, metallurgy and both capital and operational cost. Differences in water cut, temperature, pressure...... and fluid chemistry can impact on the observed H2S concentration, meaning that an increase in H2S concentration does not always correlate with activity of SRP. However it wasn't until the 1990s that SRP activity was accepted as the leading cause of reservoir souring (i.e. an increase in H2S concentrations...... to reservoir souring. This has led to some recent advances in microbial control and detection, however, despite this, many of the methods used routinely for microbial control and detection are over a century old. We therefore look towards emerging and novel mitigation technologies that may be used...

Acoustic and mechanical response of reservoir rocks under variable saturation and effective pressure.

Science.gov (United States)

Ravazzoli, C L; Santos, J E; Carcione, J M

2003-04-01

We investigate the acoustic and mechanical properties of a reservoir sandstone saturated by two immiscible hydrocarbon fluids, under different saturations and pressure conditions. The modeling of static and dynamic deformation processes in porous rocks saturated by immiscible fluids depends on many parameters such as, for instance, porosity, permeability, pore fluid, fluid saturation, fluid pressures, capillary pressure, and effective stress. We use a formulation based on an extension of Biot's theory, which allows us to compute the coefficients of the stress-strain relations and the equations of motion in terms of the properties of the single phases at the in situ conditions. The dry-rock moduli are obtained from laboratory measurements for variable confining pressures. We obtain the bulk compressibilities, the effective pressure, and the ultrasonic phase velocities and quality factors for different saturations and pore-fluid pressures ranging from normal to abnormally high values. The objective is to relate the seismic and ultrasonic velocity and attenuation to the microstructural properties and pressure conditions of the reservoir. The problem has an application in the field of seismic exploration for predicting pore-fluid pressures and saturation regimes.

Effect of rock rheology on fluid leak- off during hydraulic fracturing

Science.gov (United States)

Yarushina, V. M.; Bercovici, D.; Oristaglio, M. L.

2012-04-01

In this communication, we evaluate the effect of rock rheology on fluid leak­off during hydraulic fracturing of reservoirs. Fluid leak-off in hydraulic fracturing is often nonlinear. The simple linear model developed by Carter (1957) for flow of fracturing fluid into a reservoir has three different regions in the fractured zone: a filter cake on the fracture face, formed by solid additives from the fracturing fluid; a filtrate zone affected by invasion of the fracturing fluid; and a reservoir zone with the original formation fluid. The width of each zone, as well as its permeability and pressure drop, is assumed to remain constant. Physical intuition suggests some straightforward corrections to this classical theory to take into account the pressure dependence of permeability, the compressibility or non-Newtonian rheology of fracturing fluid, and the radial (versus linear) geometry of fluid leak­off from the borehole. All of these refinements, however, still assume that the reservoir rock adjacent to the fracture face is non­deformable. Although the effect of poroelastic stress changes on leak-off is usually thought to be negligible, at the very high fluid pressures used in hydraulic fracturing, where the stresses exceed the rock strength, elastic rheology may not be the best choice. For example, calculations show that perfectly elastic rock formations do not undergo the degree of compaction typically seen in sedimentary basins. Therefore, pseudo-elastic or elastoplastic models are used to fit observed porosity profiles with depth. Starting from balance equations for mass and momentum for fluid and rock, we derive a hydraulic flow equation coupled with a porosity equation describing rock compaction. The result resembles a pressure diffusion equation with the total compressibility being a sum of fluid, rock and pore-space compressibilities. With linear elastic rheology, the bulk formation compressibility is dominated by fluid compressibility. But the possibility

Multi-fluid renewable geo-energy systems and methods

Science.gov (United States)

Buscheck, Thomas A.

2017-08-22

A geo-energy production method for extracting thermal energy from a reservoir formation. A production well extracts brine from the reservoir formation. A plurality of working fluid injection ("WFI") wells may be arranged proximate to the production well to at least partially circumscribe the production well. A plurality of brine production ("BP") wells may be arranged in a vicinity of the WFI wells to at least partially circumscribe the WFI wells. A working fluid is injected into the WFI wells to help drive a flow of the brine up through the production and BP wells, together with at least a portion of the injected working fluid. Parasitic-load time-shifting and to storing of excess solar thermal energy may also be performed.

Shale characteristics impact on Nuclear Magnetic Resonance (NMR fluid typing methods and correlations

Directory of Open Access Journals (Sweden)

Mohamed Mehana

2016-06-01

Full Text Available The development of shale reservoirs has brought a paradigm shift in the worldwide energy equation. This entails developing robust techniques to properly evaluate and unlock the potential of those reservoirs. The application of Nuclear Magnetic Resonance techniques in fluid typing and properties estimation is well-developed in conventional reservoirs. However, Shale reservoirs characteristics like pore size, organic matter, clay content, wettability, adsorption, and mineralogy would limit the applicability of the used interpretation methods and correlation. Some of these limitations include the inapplicability of the controlling equations that were derived assuming fast relaxation regime, the overlap of different fluids peaks and the lack of robust correlation to estimate fluid properties in shale. This study presents a state-of-the-art review of the main contributions presented on fluid typing methods and correlations in both experimental and theoretical side. The study involves Dual Tw, Dual Te, and doping agent's application, T1-T2, D-T2 and T2sec vs. T1/T2 methods. In addition, fluid properties estimation such as density, viscosity and the gas-oil ratio is discussed. This study investigates the applicability of these methods along with a study of the current fluid properties correlations and their limitations. Moreover, it recommends the appropriate method and correlation which are capable of tackling shale heterogeneity.

Percolation experiments to determine fluid-matrix interaction (with particular regard to pretreatment of the drill core); Kerndurchstroemungsversuche zur Ermittlung von Fluid-Matrix-Wechselwirkungen (unter besonderer Beruecksichtigung der Kernvorbehandlung)

Energy Technology Data Exchange (ETDEWEB)

Martin, M; Seibt, A [TU Bergakademie Freiberg (Germany). Inst. fuer Bohrtechnik und Fluidbergbau; Hoth, P [GeoForschungsZentrum Potsdam (Germany)

1997-12-01

The injection of fluids into sandstone reservoirs leads to interactions between these waters, the reservoir rocks, and the formation fluids. Estimations about possible permeability reducing processes caused by these interactions are therefore of great importance for the exploitation of sandstone aquifers as geothermal reservoirs. Percolation experiments under in situ conditions with core samples from North German geothermal boreholes were done in order to investigate these fluid-rock interactions. (orig./AKF) [Deutsch] Die Injektion von Fluiden in Aquiferspeicher fuehrt zu Wechselwirkungen zwischen dem Speichergestein, den Formationsfluiden und den injizierten Loesungen. Fuer die Bewirtschaftung der Speicher sind insbesondere Kenntnisse ueber moegliche Permeabilitaetsreduzierungen durch diese Wechselwirkungen von Bedeutung. Mit Hilfe von Kern-Durchstroemungsexperimenten, durchgefuehrt unter lagerstaettenaehnlichen Bedingungen mit Original- bzw. modifizierten Fluiden, wurde daher das Durchstroemungsverhalten von unterschiedlich ausgebildeten Reservoirsandsteinen aus norddeutschen Geothermiebohrungen untersucht. (orig./AKF)

Modeling of Dynamic Fluid Forces in Fast Switching Valves

DEFF Research Database (Denmark)

Roemer, Daniel Beck; Johansen, Per; Pedersen, Henrik Clemmensen

2015-01-01

Switching valves experience opposing fluid forces due to movement of the moving member itself, as the surrounding fluid volume must move to accommodate the movement. This movement-induced fluid force may be divided into three main components; the added mass term, the viscous term and the socalled...... history term. For general valve geometries there are no simple solution to either of these terms. During development and design of such switching valves, it is therefore, common practice to use simple models to describe the opposing fluid forces, neglecting all but the viscous term which is determined...... based on shearing areas and venting channels. For fast acting valves the opposing fluid force may retard the valve performance significantly, if appropriate measures are not taken during the valve design. Unsteady Computational Fluid Dynamics (CFD) simulations are available to simulate the total fluid...

Hydrogeochemistry and reservoir model of Fuzhou geothermal field, China

Science.gov (United States)

Huang, H. F.; Goff, Fraser

1986-03-01

Fuzhou geothermal field is a low- to intermediate-temperature geothermal system consisting of meteoric water that circulates deeply along faults. The area of the field is about 9 km 2 but it is elongated in a NNW-trending direction. Fluids in the field are controlled by a series of four NNW extensional faults in Cretaceous granitic basement (Fuzhou fault zone). These faults feed warm waters into overlying permeable Quaternary sediments. The hydrothermal system consists of north and south parts whose chemical compositions are subtly different. In the northern part the system discharges sulfate/chloride waters with relatively low chloride concentrations, but in the south the system discharges chloride waters having relatively high chloride concentrations. Maximum wellhead temperatures are 97°C, which agrees with the chalcedony geothermometer in many cases. Based on the solubility of quartz, the deep-reservoir temperature cannot exceed 123 to 131°C. From heat and mass balance calculations, we conclude that the present total extracted capacity of fluid from the reservoir (20,000 tons/day) could be doubled without noticeable drawdown. We estimate the recoverable heat in the reservoir to be about 1.71 × 10 11 MJ.

Improved recovery from Gulf of Mexico reservoirs. Quarterly status report, January 1--March 31, 1996

Energy Technology Data Exchange (ETDEWEB)

Kimbrell, W.C.; Bassiouni, Z.A.; Bourgoyne, A.T.

1996-04-30

On February 18, 1992, Louisiana State University with two technical subcontractors, BDM, Inc. and ICF, Inc., began a research program to estimate the potential oil and gas reserve additions that could result from the application of advanced secondary and enhanced oil recovery technologies and the exploitation of undeveloped and attic oil zones in the Gulf of Mexico oil fields that are related to piercement salt domes. This project is a one year continuation of this research and will continue work in reservoir description, extraction processes, and technology transfer. Detailed data will be collected for two previously studies reservoirs: a South Marsh Island reservoir operated by Taylor Energy and one additional Gulf of Mexico reservoir operated by Mobil. Additional reservoirs identified during the project will also be studied if possible. Data collected will include reprocessed 2-D seismic data, newly acquired 3-D data, fluid data, fluid samples, pressure data, well test data, well logs, and core data/samples. The new data will be used to refine reservoir and geologic characterization of these reservoirs. Further laboratory investigation will provide additional simulation input data in the form of PVT properties, relative permeabilities, capillary pressure, and water compatibility. Geological investigations will be conducted to refine the models of mud-rich submarine fan architectures used by seismic analysts and reservoir engineers. Research on advanced reservoir simulation will also be conducted. This report describes a review of fine-grained submarine fans and turbidite systems.

Integrated Reflection Seismic Monitoring and Reservoir Modeling for Geologic CO2 Sequestration

Energy Technology Data Exchange (ETDEWEB)

John Rogers

2011-12-31

developed from this injection was observed migrating due to gravity to the apexes of the double anticline in the Crow Mountain reservoir of the Teapot dome. Four models were generated from the reservoir simulation task of the project which included three saturation models representing snapshots at different times during and after simulated CO{sub 2} injection and a fully saturated CO{sub 2} fluid substitution model. The saturation models were used along with a Gassmann fluid substitution model for CO{sub 2} to perform fluid volumetric substitution in the Crow Mountain formation. The fluid substitution resulted in a velocity and density model for the 3D volume at each saturation condition that was used to generate a synthetic seismic survey. FPTI's (Fusion Petroleum Technologies Inc.) proprietary SeisModelPRO{trademark} full acoustic wave equation software was used to simulate acquisition of a 3D seismic survey on the four models over a subset of the field area. The simulated acquisition area included the injection wells and the majority of the simulated plume area.

Seismic reservoir characterization: how can multicomponent data help?

International Nuclear Information System (INIS)

Li, Xiang-Yang; Zhang, Yong-Gang

2011-01-01

This paper discusses the concepts of multicomponent seismology and how it can be applied to characterize hydrocarbon reservoirs, illustrated using a 3D three-component real-data example from southwest China. Hydrocarbon reservoirs formed from subtle lithological changes, such as stratigraphic traps, may be delineated from changes in P- and S-wave velocities and impedances, whilst hydrocarbon reservoirs containing aligned fractures are anisotropic. Examination of the resultant split shear waves can give us a better definition of their internal structures. Furthermore, frequency-dependent variations in seismic attributes derived from multicomponent data can provide us with vital information about fluid type and distribution. Current practice and various examples have demonstrated the undoubted potential of multicomponent seismic in reservoir characterization. Despite all this, there are still substantial challenges ahead. In particular, the improvement and interpretation of converted-wave imaging are major hurdles that need to be overcome before multicomponent seismic becomes a mainstream technology

Seismic reservoir characterization: how can multicomponent data help?

Science.gov (United States)

Li, Xiang-Yang; Zhang, Yong-Gang

2011-06-01

This paper discusses the concepts of multicomponent seismology and how it can be applied to characterize hydrocarbon reservoirs, illustrated using a 3D three-component real-data example from southwest China. Hydrocarbon reservoirs formed from subtle lithological changes, such as stratigraphic traps, may be delineated from changes in P- and S-wave velocities and impedances, whilst hydrocarbon reservoirs containing aligned fractures are anisotropic. Examination of the resultant split shear waves can give us a better definition of their internal structures. Furthermore, frequency-dependent variations in seismic attributes derived from multicomponent data can provide us with vital information about fluid type and distribution. Current practice and various examples have demonstrated the undoubted potential of multicomponent seismic in reservoir characterization. Despite all this, there are still substantial challenges ahead. In particular, the improvement and interpretation of converted-wave imaging are major hurdles that need to be overcome before multicomponent seismic becomes a mainstream technology.

A Novel 3D Viscoelastic Acoustic Wave Equation Based Update Method for Reservoir History Matching

KAUST Repository

Katterbauer, Klemens

2014-01-01

of fluid fronts within the reservoir and determine the displacement caused by the injected fluids. This in turn has led to enhanced production strategies, cost reduction and increased profits. Conventional approaches to incorporate seismic data

Geothermal Field Investigations of Turkey

Science.gov (United States)

Sayın, N.; Özer, N.

2017-12-01

Geothermal energy is a type of energy that are found in the accessible depth of the crust, in the reservoirs by way of the permeable rocks, specially in heated fluid. Geothermal system is made of 3 main components; heat source, reservoir, and fluid bearing heat. Geothermal system mechanism is comprise of fluid transmission. Convection current (heat transmission) is caused by heating and causes the fluid in the system to expand. Heated fluid with low density show tendency to rise in system. Geothermal system occurs with variable geophysics and geochemical properties. Geophysical methods can determine structural properties of shallow and deep reservoirs with temperature, mineralization, gas amount, fluid movement, faulting, and sudden change in lithostratigraphic strata. This study revealed possible reservoir structures and showed examples of geophysics and gas measuring results in Turkey which is wealthy in regard to Geothermal sources.

INTEGRATED GEOLOGIC-ENGINEERING MODEL FOR REEF AND CARBONATE SHOAL RESERVOIRS ASSOCIATED WITH PALEOHIGHS: UPPER JURASSIC SMACKOVER FORMATION, NORTHEASTERN GULF OF MEXICO

Energy Technology Data Exchange (ETDEWEB)

Ernest A. Mancini

2001-09-14

The University of Alabama in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company are undertaking an integrated, interdisciplinary geoscientific and engineering research project. The project is designed to characterize and model reservoir architecture, pore systems and rock-fluid interactions at the pore to field scale in Upper Jurassic Smackover reef and carbonate shoal reservoirs associated with varying degrees of relief on pre-Mesozoic basement paleohighs in the northeastern Gulf of Mexico. The project effort includes the prediction of fluid flow in carbonate reservoirs through reservoir simulation modeling which utilizes geologic reservoir characterization and modeling and the prediction of carbonate reservoir architecture, heterogeneity and quality through seismic imaging. The primary objective of the project is to increase the profitability, producibility and efficiency of recovery of oil from existing and undiscovered Upper Jurassic fields characterized by reef and carbonate shoals associated with pre-Mesozoic basement paleohighs. The principal research effort for Year 1 of the project has been reservoir description and characterization. This effort has included four tasks: (1) geoscientific reservoir characterization, (2) the study of rock-fluid interactions, (3) petrophysical and engineering characterization and (4) data integration. This work was scheduled for completion in Year 1. Overall, the project work is on schedule. Geoscientific reservoir characterization is essentially completed. The architecture, porosity types and heterogeneity of the reef and shoal reservoirs at Appleton and Vocation Fields have been characterized using geological and geophysical data. The study of rock-fluid interactions has been initiated. Observations regarding the diagenetic processes influencing pore system development and heterogeneity in these reef and shoal reservoirs have been

analysis of pressure variation of fluid in bounded circular reservoirs

African Journals Online (AJOL)

user

analysis of the analysed finite element, imposing the boundary conditions and finally, getting the results that ... in reservoir engineering applications [2–7]. ... THEORY. The law of conservation of mass, Darcy's law and the equation of state has been combined to obtain the ..... fields in laser-two-layer solids weak interactions.

Hydraulic Properties of Closely Spaced Dipping Open Fractures Intersecting a Fluid-Filled Borehole Derived From Tube Wave Generation and Scattering

Science.gov (United States)

Minato, Shohei; Ghose, Ranajit; Tsuji, Takeshi; Ikeda, Michiharu; Onishi, Kozo

2017-10-01

Fluid-filled fractures and fissures often determine the pathways and volume of fluid movement. They are critically important in crustal seismology and in the exploration of geothermal and hydrocarbon reservoirs. We introduce a model for tube wave scattering and generation at dipping, parallel-wall fractures intersecting a fluid-filled borehole. A new equation reveals the interaction of tube wavefield with multiple, closely spaced fractures, showing that the fracture dip significantly affects the tube waves. Numerical modeling demonstrates the possibility of imaging these fractures using a focusing analysis. The focused traces correspond well with the known fracture density, aperture, and dip angles. Testing the method on a VSP data set obtained at a fault-damaged zone in the Median Tectonic Line, Japan, presents evidences of tube waves being generated and scattered at open fractures and thin cataclasite layers. This finding leads to a new possibility for imaging, characterizing, and monitoring in situ hydraulic properties of dipping fractures using the tube wavefield.

Integrating gravimetric and interferometric synthetic aperture radar data for enhancing reservoir history matching of carbonate gas and volatile oil reservoirs

KAUST Repository

Katterbauer, Klemens

2016-08-25

Reservoir history matching is assuming a critical role in understanding reservoir characteristics, tracking water fronts, and forecasting production. While production data have been incorporated for matching reservoir production levels and estimating critical reservoir parameters, the sparse spatial nature of this dataset limits the efficiency of the history matching process. Recently, gravimetry techniques have significantly advanced to the point of providing measurement accuracy in the microgal range and consequently can be used for the tracking of gas displacement caused by water influx. While gravity measurements provide information on subsurface density changes, i.e., the composition of the reservoir, these data do only yield marginal information about temporal displacements of oil and inflowing water. We propose to complement gravimetric data with interferometric synthetic aperture radar surface deformation data to exploit the strong pressure deformation relationship for enhancing fluid flow direction forecasts. We have developed an ensemble Kalman-filter-based history matching framework for gas, gas condensate, and volatile oil reservoirs, which synergizes time-lapse gravity and interferometric synthetic aperture radar data for improved reservoir management and reservoir forecasts. Based on a dual state-parameter estimation algorithm separating the estimation of static reservoir parameters from the dynamic reservoir parameters, our numerical experiments demonstrate that history matching gravity measurements allow monitoring the density changes caused by oil-gas phase transition and water influx to determine the saturation levels, whereas the interferometric synthetic aperture radar measurements help to improve the forecasts of hydrocarbon production and water displacement directions. The reservoir estimates resulting from the dual filtering scheme are on average 20%-40% better than those from the joint estimation scheme, but require about a 30% increase in

Detecting rapid mass movements using electrical self-potential measurements

Science.gov (United States)

Heinze, Thomas; Limbrock, Jonas; Pudasaini, Shiva P.; Kemna, Andreas

2017-04-01

Rapid mass movements are a latent danger for lives and infrastructure in almost any part of the world. Often such mass movements are caused by increasing pore pressure, for example, landslides after heavy rainfall or dam breaking after intrusion of water in the dam. Among several other geophysical methods used to observe water movement, the electrical self-potential method has been applied to a broad range of monitoring studies, especially focusing on volcanism and dam leakage but also during hydraulic fracturing and for earthquake prediction. Electrical self-potential signals may be caused by various mechanisms. Though, the most relevant source of the self-potential field in the given context is the streaming potential, caused by a flowing electrolyte through porous media with electrically charged internal surfaces. So far, existing models focus on monitoring water flow in non-deformable porous media. However, as the self-potential is sensitive to hydraulic parameters of the soil, any change in these parameters will cause an alteration of the electric signal. Mass movement will significantly influence the hydraulic parameters of the solid as well as the pressure field, assuming that fluid movement is faster than the pressure diffusion. We will present results of laboratory experiments under drained and undrained conditions with fluid triggered as well as manually triggered mass movements, monitored with self-potential measurements. For the undrained scenarios, we observe a clear correlation between the mass movements and signals in the electric potential, which clearly differ from the underlying potential variations due to increased saturation and fluid flow. In the drained experiments, we do not observe any measurable change in the electric potential. We therefore assume that change in fluid properties and release of the load causes disturbances in flow and streaming potential. We will discuss results of numerical simulations reproducing the observed effect. Our

Geological Model of Supercritical Geothermal Reservoir on the Top of the Magma Chamber

Science.gov (United States)

Tsuchiya, N.

2017-12-01

We are conducting supercritical geothermal project, and deep drilling project named as "JBBP: Japan Beyond Brittle Project" The temperatures of geothermal fields operating in Japan range from 200 to 300 °C (average 250 °C), and the depths range from 1000 to 2000 m (average 1500 m). In conventional geothermal reservoirs, the mechanical behavior of the rocks is presumed to be brittle, and convection of the hydrothermal fluid through existing network is the main method of circulation in the reservoir. In order to minimize induced seismicity, a rock mass that is "beyond brittle" is one possible candidate, because the rock mechanics of "beyond brittle" material is one of plastic deformation rather than brittle failure. To understand the geological model of a supercritical geothermal reservoir, granite-porphyry system, which had been formed in subduction zone, was investigated as a natural analog of the supercritical geothermal energy system. Quartz veins, hydrothermal breccia veins, and glassy veins are observed in a granitic body. The glassy veins formed at 500-550 °C under lithostatic pressures, and then pressures dropped drastically. The solubility of silica also dropped, resulting in formation of quartz veins under a hydrostatic pressure regime. Connections between the lithostatic and hydrostatic pressure regimes were key to the formation of the hydrothermal breccia veins, and the granite-porphyry system provides useful information for creation of fracture clouds in supercritical geothermal reservoirs. A granite-porphyry system, associated with hydrothermal activity and mineralization, provides a suitable natural analog for studying a deep-seated geothermal reservoir where stockwork fracture systems are created in the presence of supercritical geothermal fluids. I describe fracture networks and their formation mechanisms using petrology and fluid inclusion studies in order to understand this "beyond brittle" supercritical geothermal reservoir, and a geological

Reservoir Space Evolution of Volcanic Rocks in Deep Songliao Basin, China

Science.gov (United States)

Zheng, M.; Wu, X.; Zheng, M.; HU, J.; Wang, S.

2015-12-01

Recent years, large amount of natural gas has been discovered in volcanic rock of Lower Crataceous of Songliao basin. Volcanic reservoirs have become one of the important target reservoir types of eastern basin of China. In order to study the volcanic reservoirs, we need to know the main factors controlling the reservoir space. By careful obsercation on volcanic drilling core, casting thin sections and statistical analysis of petrophysical properties of volcanic reservoir in Songliao basin, it can be suggested that the igneous rock reservoir in Yingcheng formation of Lower Crataceous is composed of different rock types, such ad rohylite, rohylitic crystal tuff, autoclastic brecciation lava and so on. There are different reservoirs storage space in in various lithological igneous rocks, but they are mainly composed of primary stoma, secondary solution pores and fractures.The evolution of storage space can be divided into 3 stage: the pramary reservoir space,exogenic leaching process and burial diagenesis.During the evolution process, the reservoir space is effected by secondary minerals, tectonic movement and volcanic hydrothermal solution. The pore of volcanic reservoirs can be partially filled by secondary minerals, but also may be dissoluted by other chemical volcanic hydrothermal solution. Therefore, the favorable places for better-quality volcanic reservoirs are the near-crater facies of vocanic apparatus and dissolution zones on the high position of paleo-structures.

The Applicability of Different Fluid Media to Measure Effective Stress Coefficient for Rock Permeability

Directory of Open Access Journals (Sweden)

Ying Wang

2015-01-01

Full Text Available Effective stress coefficient for permeability (ESCK is the key parameter to evaluate the properties of reservoir stress sensitivity. So far, little studies have clarified which ESCK is correct for a certain reservoir while rock ESCK is measured differently by different fluid media. Thus, three different fluids were taken to measure a fine sandstone sample’s ESCK, respectively. As a result, the ESCK was measured to be the smallest by injecting nitrogen, the largest by injecting water, and between the two by brine. Besides, those microcharacteristics such as rock component, clay mineral content, and pore structure were further analyzed based on some microscopic experiments. Rock elastic modulus was reduced when water-sensitive clay minerals were encountered with aqua fluid media so as to enlarge the rock ESCK value. Moreover, some clay minerals reacting with water can spall and possibly block pore throats. Compared with water, brine can soften the water sensitivity; however, gas has no water sensitivity effects. Therefore, to choose which fluid medium to measure reservoir ESCK is mainly depending on its own exploitation conditions. For gas reservoirs using gas to measure ESCK is more reliable than water or brine, while using brine is more appropriate for oil reservoirs.

Effects of Formation Damage on Productivity of Underground Gas Storage Reservoirs

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C.I.C. Anyadiegwu

2013-12-01

Full Text Available Analysis of the effects of formation damage on the productivity of gas storage reservoirs was performed with depleted oil reservoir (OB-02, located onshore, Niger Delta, Nigeria. Information on the reservoir and the fluids from OB-02 were collected and used to evaluate the deliverabilities of the gas storage reservoir over a 10-year period of operation. The results obtained were used to plot graphs of deliverability against permeability and skin respectively. The graphs revealed that as the permeability decreased, the skin increased, and hence a decrease in deliverability of gas from the reservoir during gas withdrawal. Over the ten years of operating the reservoir for gas storage, the deliverability and permeability which were initially 2.7 MMscf/d and 50 mD, with a skin of 0.2, changed to new values of 0.88 MMscf/d and 24 mD with the skin as 4.1 at the tenth year.

Carbonate reservoirs modified by magmatic intrusions in the Bachu area, Tarim Basin, NW China

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Kang Xu

2015-09-01

Full Text Available Oil and gas exploration in carbonate rocks was extremely successful in recent years in the Ordovician in Tarim Basin, NW China. Here, we investigate the carbonate reservoirs in the Bachu area of the Tarim Basin through petrological and geochemical studies combined with oil and gas exploration data. Geochemical analysis included the major, trace, and rare earth elements; fluid inclusion thermometry; clay mineral characterization; and carbon and oxygen isotopes of the carbonate rocks. Homogenization temperatures of the fluid inclusions of Well He-3 in the Bachu area indicate three groups, 60–80 °C, 90–130 °C, and 140–170 °C, and suggest that the carbonate rocks experienced modification due to heating events. The porosity in the reservoir is defined by fractures and secondary pores, and there is a notable increase in the porosity of the carbonate reservoirs in proximity to magmatic intrusion, particularly approximately 8–10 m from the intrusive rocks. The development of secondary pores was controlled by lithofacies and corrosion by various fluids. We identify supercritical fluids with high density (138.12–143.97 mg/cm3 in the Bachu area. The negative correlations of δ13C (−2.76‰ to −0.97‰ and δ18O (−7.91‰ to −5.07‰ suggest that the carbonate rocks in the study area were modified by high-salinity hydrothermal fluid. The formation of clay minerals, such as illite and montmorillonite, caused a decrease in porosity. Our study demonstrates the effect of magmatic intrusions in modifying the reservoir characteristics of carbonate rocks and has important implications for oil and gas exploration.

Sampling from stochastic reservoir models constrained by production data

Energy Technology Data Exchange (ETDEWEB)

Hegstad, Bjoern Kaare

1997-12-31

When a petroleum reservoir is evaluated, it is important to forecast future production of oil and gas and to assess forecast uncertainty. This is done by defining a stochastic model for the reservoir characteristics, generating realizations from this model and applying a fluid flow simulator to the realizations. The reservoir characteristics define the geometry of the reservoir, initial saturation, petrophysical properties etc. This thesis discusses how to generate realizations constrained by production data, that is to say, the realizations should reproduce the observed production history of the petroleum reservoir within the uncertainty of these data. The topics discussed are: (1) Theoretical framework, (2) History matching, forecasting and forecasting uncertainty, (3) A three-dimensional test case, (4) Modelling transmissibility multipliers by Markov random fields, (5) Up scaling, (6) The link between model parameters, well observations and production history in a simple test case, (7) Sampling the posterior using optimization in a hierarchical model, (8) A comparison of Rejection Sampling and Metropolis-Hastings algorithm, (9) Stochastic simulation and conditioning by annealing in reservoir description, and (10) Uncertainty assessment in history matching and forecasting. 139 refs., 85 figs., 1 tab.

The impact of intermediate wet states on two-phase flow in porous media, studied by network modelling

Energy Technology Data Exchange (ETDEWEB)

Hoeiland, Linda Kaada

2006-04-15

Reservoir wettability is a measure of a rocks preference for the oil and/or the brine phase. Wettability has a dominant impact on fluid movements in porous media, hence oil displacement in reservoir rocks. Understanding the local wettability and the effect of wettability on the fluid movements are therefore of interest in relation to oil recovery processes. Contrary to the earlier believed homogenous wetted cases where the porous media was strongly oil-wet for carbonate reservoirs or strongly water-wet for clastic reservoirs, it is now believed that most reservoir rocks experience some kind of intermediate wet state. Since wettability affects oil recovery, different classes of intermediate wettability are expected to have different impacts on the fluid flow processes. The major subject treated in this thesis is how different intermediate wet states affect fluid flow parameters which are important for the oil recovery. This is done by use of a capillary dominated network model of two-phase flow, where the network is based on a model of reconstructed sandstone. The existence of different intermediate wet classes is argued in Paper I, while Paper II, III and IV analyse the effect different intermediate wet classes have on wettability indices, residual oil saturation, capillary pressure and relative permeability (author)

Hydrothermal dolomite reservoir facies in the Sinian Dengying Fm, central Sichuan Basin

Directory of Open Access Journals (Sweden)

Yuqiang Jiang

2017-07-01

Full Text Available The Upper Sinian Dengying Fm is the focus of natural gas exploration in the central part of the Sichuan Basin (central Sichuan Basin in recent years. Especially, epigenic karstification and its resulted reservoir-seepage spaces have always been the focal points in researches. Based on the petrographic characteristics of drilling cuttings and core samples, and through experimental analysis by using trace elements, isotopes, and cathodoluminescence, the Dengying Fm dolomite was demonstrated to have matrix recrystallized dolomite (MRD, filled saddle dolomite (FSD (the mean homogenization temperature of inclusion: 178.5 °C, high concentrations of Fe & Mn, slightly positive 87Sr/86Sr value and hydrothermal minerals combination (including sphalerite, galena, pyrite, and quartz, etc.. Thus, it was proposed that hydrothermal dolomite reservoir facies (HDRF exist in the Dengying Fm dolomite, in other words, the dolomite reservoir is composed of hydrothermal dissolved pores, intercrystalline pores of hydrothermal origin, hydrothermal caverns and expanded fractures, and was formed due to the reworking of hydrothermal fluid on tight matrix dolomite. Identification marks are presented in terms of petrography and geochemistry so that hydrothermal dolomite reservoir facies can be effectively recognized and identified. It is concluded that the development of hydrothermal dolomite reservoir facies in this area are preliminary controlled by deep and large basement faults and the strength of hydrothermal fluids.

Fluid Behavior and Fluid-Solid Interactions in Nanoporous Media

Science.gov (United States)

Xu, H.

2015-12-01

Although shale oil/gas production in the US has increased exponentially, the low energy recovery is a daunting problem needed to be solved for its sustainability and continued growth, especially in light of the recent oil/gas price decline. This is apparently related to the small porosity (a few to a few hundred nm) and low permeability (10-16-10-20 m2) of tight shale formations. The fundamental question lies in the anomalous behavior of fluids in nanopores due to confinement effects, which, however, remains poorly understood. In this study, we combined experimental characterization and observations, particularly using small-angle neutron scattering (SANS), with pore-scale modeling using lattice Boltzmann method (LBM), to examine the fluid behavior and fluid-solid interactions in nanopores at reservoir conditions. Experimentally, we characterized the compositions and microstructures of a shale sample from Wolfcamp, Texas, using a variety of analytical techniques. Our analyses reveal that the shale sample is made of organic-matter (OM)-lean and OM-rich layers that exhibit different chemical and mineral compositions, and microstructural characteristics. Using the hydrostatic pressure system and gas-mixing setup we developed, in-situ SANS measurements were conducted at pressures up to 20 kpsi on shale samples imbibed with water or water-methane solutions. The obtained results indicate that capillary effect plays a significant role in fluid-nanopore interactions and the associated changes in nanopore structures vary with pore size and pressure. Computationally, we performed LBM modeling to simulate the flow behavior of methane in kerogen nanoporous structure. The correction factor, which is the ratio of apparent permeability to intrinsic permeability, was calculated. Our results show that the correction factor is always greater than one (non-continuum/non-Darcy effects) and increases with decreasing nanopore size, intrinsic permeability and pressure. Hence, the

Application of fractal theory in refined reservoir description for EOR pilot area

Energy Technology Data Exchange (ETDEWEB)

Yue Li; Yonggang Duan; Yun Li; Yuan Lu

1997-08-01

A reliable reservoir description is essential to investigate scenarios for successful EOR pilot test. Reservoir characterization includes formation composition, permeability, porosity, reservoir fluids and other petrophysical parameters. In this study, various new tools have been applied to characterize Kilamayi conglomerate formation. This paper examines the merits of various statistical methods for recognizing rock property correlation in vertical columns and gives out methods to determine fractal dimension including R/S analysis and power spectral analysis. The paper also demonstrates that there is obvious fractal characteristics in conglomerate reservoirs of Kilamayi oil fields. Well log data in EOR pilot area are used to get distribution profile of parameters including permeability, porosity, water saturation and shale content.

Chemical and physical reservoir parameters at initial conditions in Berlin geothermal field, El Salvador: a first assessment

Energy Technology Data Exchange (ETDEWEB)

D`Amore, F. [CNR, Pisa (Italy). International Institute for Geothermal Research ; Mejia, J.T. [Comision Ejuctiva Hidroelectrica del Rio Lempa, El Salvador (El Salvador)

1999-02-01

A study has been made to obtain the main chemical and physical reservoir conditions of the Berlin field (El Salvador), before the commencement of large-scale exploitation of the geothermal resource. The upflow zone and the main flow path within the geothermal system have been determined from the area distribution of chemical parameters such as Cl concentrations, ratios such as Na/K, K/Mg, K/Ca, and temperatures computed from silica concentrations and cation ratios. Gas compositions have been used to calculate reservoir parameters such as temperature, steam fraction and P{sub CO{sub 2}}. The computer code WATCH (new edition 1994) has been used to evaluate the temperature of equilibrium between the aqueous species and selected alteration minerals in the reservoir. The fluid in Berlin flows to the exploited reservoir from the south, entering it in the vicinity of well TR-5. Along its flow-path (south-north direction), the fluid is cooled by boiling and conductive cooling. The chloride-enthalpy diagram indicates the existence of a parent water, with a chemical composition similar to well TR-5, that boils and the residual brine produces the fluid of well TR-3, which is very concentrated in salts. The fluid of TR-5 is probably produced from this parent water, generating the fluids of wells TR-2 and TR-9 by boiling, and the fluids of wells TR-1 and TR-4 by conductive cooling. The computed values for the deep steam fraction clearly indicate that this is a liquid-dominated system, with computed temperature values decreasing from 310{sup o}C (upflow zone) to about 230{sup o}C, from south to north. (author)

The role of brain barriers in fluid movement in the CNS: is there a 'glymphatic' system?

Science.gov (United States)

Abbott, N Joan; Pizzo, Michelle E; Preston, Jane E; Janigro, Damir; Thorne, Robert G

2018-03-01

Brain fluids are rigidly regulated to provide stable environments for neuronal function, e.g., low K + , Ca 2+ , and protein to optimise signalling and minimise neurotoxicity. At the same time, neuronal and astroglial waste must be promptly removed. The interstitial fluid (ISF) of the brain tissue and the cerebrospinal fluid (CSF) bathing the CNS are integral to this homeostasis and the idea of a glia-lymph or 'glymphatic' system for waste clearance from brain has developed over the last 5 years. This links bulk (convective) flow of CSF into brain along the outside of penetrating arteries, glia-mediated convective transport of fluid and solutes through the brain extracellular space (ECS) involving the aquaporin-4 (AQP4) water channel, and finally delivery of fluid to venules for clearance along peri-venous spaces. However, recent evidence favours important amendments to the 'glymphatic' hypothesis, particularly concerning the role of glia and transfer of solutes within the ECS. This review discusses studies which question the role of AQP4 in ISF flow and the lack of evidence for its ability to transport solutes; summarizes attributes of brain ECS that strongly favour the diffusion of small and large molecules without ISF flow; discusses work on hydraulic conductivity and the nature of the extracellular matrix which may impede fluid movement; and reconsiders the roles of the perivascular space (PVS) in CSF-ISF exchange and drainage. We also consider the extent to which CSF-ISF exchange is possible and desirable, the impact of neuropathology on fluid drainage, and why using CSF as a proxy measure of brain components or drug delivery is problematic. We propose that new work and key historical studies both support the concept of a perivascular fluid system, whereby CSF enters the brain via PVS convective flow or dispersion along larger caliber arteries/arterioles, diffusion predominantly regulates CSF/ISF exchange at the level of the neurovascular unit associated with

Determination of reservoir effective porosity using nuclear magnetic logging data

International Nuclear Information System (INIS)

Aksel'rod, S.M.; Danevich, V.I.; Sadykov, D.M.

1979-01-01

In connection with the development of nuclear magnetic logging (NML) the possibility has occurred to determine the effective porosity coefficient for rocks directly under the conditions of their occurrence. The initial amplitude of a signal of free precession of NML is proportional to the quantity of free fluid in the rock volume, which is determined by the index of free fluid (IFF). On the basis of the laboratory studies it is shown that the relation between IFF and free water content is always linear and doesn't depend on lithological characteristics of rocks, porous dimensions and distribution. Using this relation it's possible to estimate bound water content. While filling the reservoir with weakly mineralized water the IFF value coincides numerically with the effective porosity coefficient. Otherwise the content of hydrogen nuclei in a volume unit is much less; while calculating the effective porosity coefficient this fact is recorded by the index of the amplitude decrease which depends on temperature and increases with its growth (for oils). In strata containing intercalations of reservoirs and non-reservoirs the averaged according to stratum IFF value determines the mean-weighted values of effective porosity

On the feasibility of inducing oil mobilization in existing reservoirs via wellbore harmonic fluid action

KAUST Repository

Jeong, Chanseok; Huh, Chun; Kallivokas, Loukas F.

2011-01-01

Although vibration-based mobilization of oil remaining in mature reservoirs is a promising low-cost method of enhanced oil recovery (EOR), research on its applicability at the reservoir scale is still at an early stage. In this paper, we use

The time-lapse AVO difference inversion for changes in reservoir parameters

Science.gov (United States)

Longxiao, Zhi; Hanming, Gu; Yan, Li

2016-12-01

The result of conventional time-lapse seismic processing is the difference between the amplitude and the post-stack seismic data. Although stack processing can improve the signal-to-noise ratio (SNR) of seismic data, it also causes a considerable loss of important information about the amplitude changes and only gives the qualitative interpretation. To predict the changes in reservoir fluid more precisely and accurately, we also need the quantitative information of the reservoir. To achieve this aim, we develop the method of time-lapse AVO (amplitude versus offset) difference inversion. For the inversion of reservoir changes in elastic parameters, we apply the Gardner equation as the constraint and convert the three-parameter inversion of elastic parameter changes into a two-parameter inversion to make the inversion more stable. For the inversion of variations in the reservoir parameters, we infer the relation between the difference of the reflection coefficient and variations in the reservoir parameters, and then invert reservoir parameter changes directly. The results of the theoretical modeling computation and practical application show that our method can estimate the relative variations in reservoir density, P-wave and S-wave velocity, calculate reservoir changes in water saturation and effective pressure accurately, and then provide reference for the rational exploitation of the reservoir.

analysis of pressure variation of fluid in an infinite acting reservoir

African Journals Online (AJOL)

user

2017-01-01

Jan 1, 2017 ... radial diffusivity equation for a reservoir acting as if it was infinite in size and ... differential equation there is an infinite number of a possible solution ..... [3] Van Everdingen, A. F. and Hurst, W. The Application of the. Laplace ...

Petroleum geochemical responses to reservoir rock properties

Energy Technology Data Exchange (ETDEWEB)

Bennett, B.; Larter, S.R. [Calgary Univ., AB (Canada)

2008-07-01

Reservoir geochemistry is used to study petroleum basin development, petroleum mixing, and alterations. In this study, polar non-hydrocarbons were used as proxies for describing reservoir properties sensitive to fluid-rock interactions. A core flood experiment was conducted on a Carboniferous siltstone core obtained from a site in the United Kingdom. Core samples were then obtained from a typical upper shoreface in a North Sea oilfield. The samples were extracted with a dichloromethane and methanol mixture. Alkylcarbazoles and alkylfluorenones were then isolated from the samples. Compositional changes along the core were also investigated. Polar non hydrocarbons were studied using a wireline gamma ray log. The strongest deflections were observed in the basal coarsening upwards unit. The study demonstrated the correlations between molecular markers, and indicated that molecular parameters can be used to differentiate between clean sand units and adjacent coarsening upward muddy sand sequences. It was concluded that reservoir geochemical parameters can provide an independent response to properties defined by petrophysical methods. 6 refs., 2 figs.

Reservoir simulation with MUFITS code: Extension for double porosity reservoirs and flows in horizontal wells

Science.gov (United States)

Afanasyev, Andrey

2017-04-01

Numerical modelling of multiphase flows in porous medium is necessary in many applications concerning subsurface utilization. An incomplete list of those applications includes oil and gas fields exploration, underground carbon dioxide storage and geothermal energy production. The numerical simulations are conducted using complicated computer programs called reservoir simulators. A robust simulator should include a wide range of modelling options covering various exploration techniques, rock and fluid properties, and geological settings. In this work we present a recent development of new options in MUFITS code [1]. The first option concerns modelling of multiphase flows in double-porosity double-permeability reservoirs. We describe internal representation of reservoir models in MUFITS, which are constructed as a 3D graph of grid blocks, pipe segments, interfaces, etc. In case of double porosity reservoir, two linked nodes of the graph correspond to a grid cell. We simulate the 6th SPE comparative problem [2] and a five-spot geothermal production problem to validate the option. The second option concerns modelling of flows in porous medium coupled with flows in horizontal wells that are represented in the 3D graph as a sequence of pipe segments linked with pipe junctions. The well completions link the pipe segments with reservoir. The hydraulics in the wellbore, i.e. the frictional pressure drop, is calculated in accordance with Haaland's formula. We validate the option against the 7th SPE comparative problem [3]. We acknowledge financial support by the Russian Foundation for Basic Research (project No RFBR-15-31-20585). References [1] Afanasyev, A. MUFITS Reservoir Simulation Software (www.mufits.imec.msu.ru). [2] Firoozabadi A. et al. Sixth SPE Comparative Solution Project: Dual-Porosity Simulators // J. Petrol. Tech. 1990. V.42. N.6. P.710-715. [3] Nghiem L., et al. Seventh SPE Comparative Solution Project: Modelling of Horizontal Wells in Reservoir Simulation

An experimental study of tracers for labelling of injection gas in oil reservoirs

International Nuclear Information System (INIS)

Dugstad, Oe.

1992-01-01

This work demonstrates the feasibility of the PMCP and PMCH as tracers in field experiments. These compounds have properties which make them as well suited for well to well studies as the more common tracers CH 3 T and 85 Kr. In an injection project carried out at the Gullfaks field in the North Sea the two PFCs verified communication between wells. This implies communication between different geological layers in the reservoir and also communication across faults within the same layers. Laboratory studies carried out have focused on the retention of the tracers in dynamic flooding experiments under conditions comparable with those in the petroleum reservoirs. Simultaneous injection of a variety of tracers has shown individual variations in tracer retention which are caused by important reservoir parameters as fluid saturation and rock properties. By proper design of field injection programs the tracers response may therefore be used to estimate fluid saturation if actual rock properties are known. 45 refs., 20 figs., 13 tabs

Reservoir Models for Gas Hydrate Numerical Simulation

Science.gov (United States)

Boswell, R.

2016-12-01

/linear way. Significant progress has also occurred in recent years with regard to the geologic characterization of reservoir boundaries. Vertical boundaries with overlying clay-rich "seals" are now widely-appreciated to have non-zero permeability, and lateral boundaries are sources of potential lateral fluid flow.

Physical modelling and the poroelastic model with application to fluid detection in a VTI medium

International Nuclear Information System (INIS)

Li, Shengjie

2013-01-01

In this paper, both poroelasticity theory and pre-stack inversions have been combined to generate a flexible way to derive an effective fluid factor, which is then used to identify the presence of the hydrocarbon in weakly anisotropic VTI reservoirs. The effective fluid factor has been derived by using an approximate fluid substitution equation for anisotropic VTI media. The approximate equation provides a means of performing fluid substitution for elastic moduli along the vertical symmetry axis of a VTI medium with fewer elastic moduli. The effective fluid factor can be used to analyse the sensitivity of seismic attributes to fluid content. In order to examine the effectiveness of the effective fluid factor, an anisotropic physical model has been constructed. The rock properties of artificial sandstone used as a reservoir building material are properly selected by using an empirical model and Gassmann's equation. An effort is made to ensure the physical modelling data represent the 'true’ response of different fluid-filled sands. The fluid detection method is then applied to interpret the inverted seismic impedance obtained from physical modelling seismic data with some known gas-sands and wet-sands. The results shows that the interpretive resolution of seismic fluid detection has been dramatically improved by using the effective fluid factor. In addition, more information on lateral changes in fluid content can be distinguished. This study has demonstrated the potential of this method in detecting different fluid content in weakly anisotropic VTI reservoirs. (paper)

Hydrocarbon accumulation characteristics and enrichment laws of multi-layered reservoirs in the Sichuan Basin

Directory of Open Access Journals (Sweden)

Guang Yang

2017-03-01

Full Text Available The Sichuan Basin represents the earliest area where natural gas is explored, developed and comprehensively utilized in China. After over 50 years of oil and gas exploration, oil and gas reservoirs have been discovered in 24 gas-dominant layers in this basin. For the purpose of predicting natural gas exploration direction and target of each layer in the Sichuan Basin, the sedimentary characteristics of marine and continental strata in this basin were summarized and the forms of multi-cycled tectonic movement and their controlling effect on sedimentation, diagenesis and hydrocarbon accumulation were analyzed. Based on the analysis, the following characteristics were identified. First, the Sichuan Basin has experienced the transformation from marine sedimentation to continental sedimentation since the Sinian with the former being dominant. Second, multiple source–reservoir assemblages are formed based on multi-rhythmed deposition, and multi-layered reservoir hydrocarbon accumulation characteristics are vertically presented. And third, multi-cycled tectonic movement appears in many forms and has a significant controlling effect on sedimentation, diagenesis and hydrocarbon accumulation. Then, oil and gas reservoir characteristics and enrichment laws were investigated. It is indicated that the Sichuan Basin is characterized by coexistence of conventional and unconventional oil and gas reservoirs, multi-layered reservoir hydrocarbon supply, multiple reservoir types, multiple trap types, multi-staged hydrocarbon accumulation and multiple hydrocarbon accumulation models. Besides, its natural gas enrichment is affected by hydrocarbon source intensity, large paleo-uplift, favorable sedimentary facies belt, sedimentary–structural discontinuity plane and structural fracture development. Finally, the natural gas exploration and research targets of each layer in the Sichuan Basin were predicted according to the basic petroleum geologic conditions

Fluid Flow in Low Permeable, Porous Media Écoulements fluides dans un milieu poreux peu perméable

Directory of Open Access Journals (Sweden)

Dutta N. C.

2006-11-01

Full Text Available Migration of hydrocarbons deals with the subsequent movement of petroleum after expulsion from the source rock through water saturated reservoirs or through permeability created by fractures and faults. Although the underlying principles that control the fluid movement in porous media (reservoirs are well understood by reservoir engineers, less is known about the flow characteristics in low-permeable, porous media, such as clays and shales. For flow considerations, the primary parameters are porosity, permeability and the fluid potential gradients. For clays and shales, these parameters are poorly known; yet these control the time periods during which fluid flow occurs in sedimentary basins (100 years to 100 million years. In this paper, I examine the parametric dependence of the time constantsof fluid flow in low permeability sediments on its porosity and permeability. This is accomplished in two parts. In the first part, a technique is presented to investigate the effect of fluid flow in shales which causes undercompaction and buildup of fluid pressures in excess of normal hydrostatic pressure. The technique is pre-drill in nature; it uses seismic velocity analysis of common depth point gather of surface seismic data and is based on the concept developed by Hottmann and Johnson (1965 and Pennebaker (1968. In the second part of the paper, the flow characteristics are discussed in the basin scale. I develop a model that describes the fluid flow in a continuously accreting and subsiding clastics basins, such as the Gulf of Mexico. I examine the pressure characteristics of such a basin by digital simulations and study the effect of the permeability variation of shales on the geologic time dependence of the fluid flux in the sediments, the basin subsidence rate and the pressure buildup with depth. The model incorporates both mechanical compaction and burial diagenesis involving smectite to illite conversion of shales. The latter is based on a

Toxic anterior segment syndrome caused by autoclave reservoir wall biofilms and their residual toxins.

Science.gov (United States)

Sorenson, Andrew L; Sorenson, Robert L; Evans, David J

2016-11-01

To identify etiology of toxic anterior segment syndrome (TASS) after uneventful phacoemulsification. EyeMD Laser and Surgery Center, Oakland, California. Retrospective case series. Patient charts with TASS were reviewed. Reservoirs of 2 autoclaves associated with these cases were cultured for bacterial contamination. Cultures were performed on 23 other autoclave reservoirs at surgery centers in the local area. The main outcome measures were the incidence of TASS and prevalence of bacterial biofilm contamination of autoclave reservoirs. From 2010 to 2013, 11 935 consecutive cataract surgeries were performed at 1 center by multiple surgeons with no reported TASS. Between January 1, 2014, and January 15, 2015, 10 cases of TASS occurred out of 3003 cataract surgeries; these patients' charts were reviewed. Cultures of 2 Statim autoclave reservoir walls grew Bacillus species, Williamsia species, Mycobacterium mucogenicum, and Candida parapsilosis. Scanning electron microscopy of reservoir wall sections showed prominent biofilm. The 2 autoclaves were replaced in January 2015. Subsequently, 2875 cataract surgeries were performed with no reported TASS (P autoclaves were also contaminated with bacterial biofilms. Toxic anterior segment syndrome was strongly associated with bacterial biofilm contamination of autoclave reservoirs. An etiological mechanism might involve transport of heat-stable bacterial cell antigens in the steam with deposition on surgical instrumentation. Data suggest widespread prevalence of bacterial biofilms on fluid-reservoir walls, despite adherence to manufacturer guidelines for cleaning and maintenance. Prevention or elimination of autoclave fluid-reservoir biofilms might reduce the risk for postoperative TASS. None of the authors has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Magmatic-like fluid source of the Chingshui geothermal field, NE Taiwan evidenced by carbonate clumped-isotope paleothermometry

Science.gov (United States)

Lu, Yi-Chia; Song, Sheng-Rong; Wang, Pei-Ling; Wu, Chung-Che; Mii, Horng-Sheng; MacDonald, John; Shen, Chuan-Chou; John, Cédric M.

2017-11-01

The Chingshui geothermal field, a moderate-temperature and water-dominated hydrothermal system, was the site of the first geothermal power plant in Taiwan. Many geological, geophysical and geochemical studies using more than 21 drilled wells have been performed since the 1960s. However, there are still controversies regarding the heat and fluid sources due to the tectonically complicated geological setting. To clarify the heat and fluid sources, we analyzed clumped isotopes with carbon and oxygen isotopic compositions of calcite scaling in geothermal wells and veins on outcrops and calculated the δ18O values of the source fluids. Two populations of δ18O values were calculated: -5.8 ± 0.8‰ VSMOW from scaling in the well and -1.0 ± 1.6‰ to 10.0 ± 1.3‰ VSMOW from outcropping calcite veins, indicative of meteoric and magmatic fluid sources, respectively. Meanwhile, two hydrothermal reservoirs at different depths have been identified by magnetotelluric (MT) imaging with micro-seismicity underneath this area. As a result, we propose a two-reservoir model: the shallow reservoir provides fluids from meteoric water for the scaling sampled from wells, whereas the deep reservoir provides magmatic fluids from deep marble decarbonization recorded in outcropping calcite veins.

Reviving Abandoned Reservoirs with High-Pressure Air Injection: Application in a Fractured and Karsted Dolomite Reservoir

Energy Technology Data Exchange (ETDEWEB)

Robert Loucks; Stephen C. Ruppel; Dembla Dhiraj; Julia Gale; Jon Holder; Jeff Kane; Jon Olson; John A. Jackson; Katherine G. Jackson

2006-09-30

Engineering (both at The University of Texas at Austin) to define the controls on fluid flow in the reservoir as a basis for developing a reservoir model. The successful development of HPAI technology has tremendous potential for increasing the flow of oil from deep carbonate reservoirs in the Permian Basin, a target resource that can be conservatively estimated at more than 1.5 billion barrels. Successful implementation in the field chosen for demonstration, for example, could result in the recovery of more than 34 million barrels of oil that will not otherwise be produced. Geological and petrophysical analysis of available data at Barnhart field reveals the following important observations: (1) the Barnhart Ellenburger reservoir is similar to most other Ellenburger reservoirs in terms of depositional facies, diagenesis, and petrophysical attributes; (2) the reservoir is characterized by low to moderate matrix porosity much like most other Ellenburger reservoirs in the Permian Basin; (3) karst processes (cave formation, infill, and collapse) have substantially altered stratigraphic architecture and reservoir properties; (4) porosity and permeability increase with depth and may be associated with the degree of karst-related diagenesis; (5) tectonic fractures overprint the reservoir, improving overall connectivity; (6) oil-saturation profiles show that the oil-water contact (OWC) is as much as 125 ft lower than previous estimations; (7) production history and trends suggest that this reservoir is very similar to other solution-gas-drive reservoirs in the Permian Basin; and (8) reservoir simulation study showed that the Barnhart reservoir is a good candidate for HPAI and that application of horizontal-well technology can improve ultimate resource recovery from the reservoir.

Gas geochemistry of the magmatic-hydrothermal fluid reservoir in the Copahue-Caviahue Volcanic Complex (Argentina)

Science.gov (United States)

Agusto, M.; Tassi, F.; Caselli, A. T.; Vaselli, O.; Rouwet, D.; Capaccioni, B.; Caliro, S.; Chiodini, G.; Darrah, T.

2013-05-01

Copahue volcano is part of the Caviahue-Copahue Volcanic Complex (CCVC), which is located in the southwestern sector of the Caviahue volcano-tectonic depression (Argentina-Chile). This depression is a pull-apart basin accommodating stresses between the southern Liquiñe-Ofqui strike slip and the northern Copahue-Antiñir compressive fault systems, in a back-arc setting with respect to the Southern Andean Volcanic Zone. In this study, we present chemical (inorganic and organic) and isotope compositions (δ13C-CO2, δ15N, 3He/4He, 40Ar/36Ar, δ13C-CH4, δD-CH4, and δD-H2O and δ18O-H2O) of fumaroles and bubbling gases of thermal springs located at the foot of Copahue volcano sampled in 2006, 2007 and 2012. Helium isotope ratios, the highest observed for a Southern American volcano (R/Ra up to 7.94), indicate a non-classic arc-like setting, but rather an extensional regime subdued to asthenospheric thinning. δ13C-CO2 values (from - 8.8‰ to - 6.8‰ vs. V-PDB), δ15N values (+ 5.3‰ to + 5.5‰ vs. Air) and CO2/3He ratios (from 1.4 to 8.8 × 109) suggest that the magmatic source is significantly affected by contamination of subducted sediments. Gases discharged from the northern sector of the CCVC show contribution of 3He-poor fluids likely permeating through local fault systems. Despite the clear mantle isotope signature in the CCVC gases, the acidic gas species have suffered scrubbing processes by a hydrothermal system mainly recharged by meteoric water. Gas geothermometry in the H2O-CO2-CH4-CO-H2 system suggests that CO and H2 re-equilibrate in a separated vapor phase at 200°-220 °C. On the contrary, rock-fluid interactions controlling CO2, CH4 production from Sabatier reaction and C3H8 dehydrogenation seem to occur within the hydrothermal reservoir at temperatures ranging from 250° to 300 °C. Fumarole gases sampled in 2006-2007 show relatively low N2/He and N2/Ar ratios and high R/Ra values with respect to those measured in 2012. Such compositional and

Visualizing the Entropy Change of a Thermal Reservoir

Science.gov (United States)

Langbeheim, Elon; Safran, Samuel A.; Yerushalmi, Edit

2014-01-01

When a system exchanges energy with a constant-temperature environment, the entropy of the surroundings changes. A lattice model of a fluid thermal reservoir can provide a visualization of the microscopic changes that occur in the surroundings upon energy transfer from the system. This model can be used to clarify the consistency of phenomena such…

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)

Phenomenology of tremor-like signals observed over hydrocarbon reservoirs

NARCIS (Netherlands)

Dangel, S.; Schaepman, M.E.; Stoll, E.P.; Carniel, R.; Barzandji, O.; Rode, E.D.; Singer, J.M.

2003-01-01

We have observed narrow-band, low-frequency (1.5-4 Hz, amplitude 0.01-10 mum/s) tremor signals on the surface over hydrocarbon reservoirs (oil, gas and water multiphase fluid systems in porous media) at currently 15 sites worldwide. These 'hydrocarbon tremors' possess remarkably similar spectral and

Fracturing Fluid Leak-off for Deep Volcanic Rock in Zhungeer Basin: Mechanism and Control Method

Directory of Open Access Journals (Sweden)

Huang Bo

2017-01-01

Full Text Available The deep volcanic reservoir in Zhungeer Basin is buried in over 4000m depth, which is characterized by complex lithology (breccia, andesite, basalt, etc., high elastic modulus and massive natural fractures. During hydraulic fracturing, hydraulic fracture will propagate and natural fractures will be triggered by the increasing net pressure. However, the extension of fractures, especially natural fractures, would aggravate the leak-off effect of fracturing fluid, and consequently decrease the fracturing success rate. 4 out of 12 fracturing wells in the field have failed to add enough proppants due to fluid loss. In order to increase the success rate and efficiency of hydraulic fracturing for deep volcanic reservoir, based on theoretical and experimental method, the mechanism of fracturing fluid leak-off is deeply studied. We propose a dualistic proppant scheme and employ the fluid loss reducer to control the fluid leak-off in macro-fractures and micro-fractures respectively. The proposed technique remarkably improved the success rate in deep volcanic rock fracturing. It bears important theoretical value and practical significance to improve the hydraulic fracturing design for deep volcanic reservoir.

Production forecasting and economic evaluation of horizontal wells completed in natural fractured reservoirs

International Nuclear Information System (INIS)

Evans, R. D.

1996-01-01

A technique for optimizing recovery of hydrocarbons from naturally fractured reservoirs using horizontal well technology was proposed. The technique combines inflow performance analysis, production forecasting and economic considerations, and is based on material balance analysis and linear approximations of reservoir fluid properties as functions of reservoir pressure. An economic evaluation model accounting for the time value of cash flow, interest and inflation rates, is part of the package. Examples of using the technique have been demonstrated. The method is also applied to a gas well producing from a horizontal wellbore intersecting discrete natural fractures. 11 refs., 2 tabs,. 10 figs

Numerical simulation of vertical infiltration for leaching fluid in situ

International Nuclear Information System (INIS)

Li Jinxuan; Shi Weijun; Zhang Weimin

1998-01-01

Based on the analysis of movement law of leaching fluid in breaking and leaching experiment in situ, the movement of leaching fluid can be divided into two main stages in the leaching process in situ: Vertical Infiltration in unsaturation zone and horizontal runoff in saturation zone. The corresponding mathematics models are sep up, and the process of vertical infiltration of leaching fluid is numerically simulated

The Tianjin geothermal field (north-eastern China): Water chemistry and possible reservoir permeability reduction phenomena

Energy Technology Data Exchange (ETDEWEB)

Minissale, Angelo; Montegrossi, Giordano; Orlando, Andrea [Institute of Geosciences and Earth Resources, National Research Council of Italy (CNR), Via G. La Pira 4, 50121 Florence (Italy); Borrini, Daniele; Tassi, Franco [Department of Earth Sciences, University of Florence, Via G. La Pira 4, 50121 Florence (Italy); Vaselli, Orlando [Institute of Geosciences and Earth Resources, National Research Council of Italy (CNR), Via G. La Pira 4, 50121 Florence (Italy); Department of Earth Sciences, University of Florence, Via G. La Pira 4, 50121 Florence (Italy); Huertas, Antonio Delgado [Estacion Experimental de Zaidin (CSIC), Prof. Albareda 1, 18008 Granada (Spain); Yang, Jincheng; Cheng, Wanquing [Aode Renewable Energy Research Institute, 90 Weijin South Road, Nankai District, 300381 Tianjin (China); Tedesco, Dario [Department of Environmental Sciences, Second University of Naples, Via Vivaldi 43, Caserta 81100 (Italy); Institute of Environmental Geology and Geo Engineering (CNR), Piazzale A. Moro 5, Roma 00100 (Italy); Poreda, Robert [Department of Earth and Environmental Sciences, University of Rochester, 227 Hutchison Hall, Rochester, NY 14627 (United States)

2008-08-15

Injection of spent (cooled) thermal fluids began in the Tianjin geothermal district, north-eastern China, at the end of the 1990s. Well injectivities declined after 3-4 years because of self-sealing processes that reduced reservoir permeability. The study focuses on the factors that may have caused the observed decrease in permeability, using chemical and isotopic data on fluids (water and gas) and mineral phases collected from production and injection wells. The results of data processing and interpretation indicate that (1) it is very unlikely that calcite and silica precipitation is taking place in the reservoir; (2) the Fe- and Zn-rich mineral phases (e.g. sulfides, hydroxides and silicates) show positive saturation indexes; (3) SEM and XRD analyses of filtered material reveal that the latter mineral phases are common; (4) visual observation of casings and surface installations, and of corrosion products, suggests that a poor quality steel was used in their manufacture; (5) significant quantities of solids (e.g. quartz and feldspar crystals) are carried by the geothermal fluid; (6) seasonal changes in fluid composition lead to a reduction in casing corrosion during the summer. It was concluded that the decrease in injectivity in the Tianjin wells is caused only in part by the oxidation of casings, downhole pumps, and surface installations, triggered by free oxygen in the injected fluids; the utilization of better quality steels should drastically reduce this type of corrosion. Self-sealing of pores and fractures by reservoir formation solids and by the Fe-corrosion products suspended in the injected fluids seems to be a more important phenomenon, whose effect could be greatly reduced by installing filtering devices at all sites. (author)

Radar Mapping of Fractures and Fluids in Hydrocarbon Reservoirs

Science.gov (United States)

Stolarczyk, L. G.; Wattley, G. G.; Caffey, T. W.

2001-05-01

A stepped-frequency radar has been developed for mapping of fractures and fluids within 20 meters of the wellbore. The operating range has been achieved by using a radiating magnetic dipole operating in the low- and medium-frequency bands. Jim Wait has shown that the electromagnetic (EM) wave impedance in an electrically conductive media is largely imaginary, enabling energy to be stored in the near field instead of dissipated, as in the case for an electric dipole. This fact, combined with the low attenuation rate of a low-frequency band EM wave, enables radiation to penetrate deeply into the geology surrounding the wellbore. The radiation pattern features a vertical electric field for optimum electric current induction into vertical fractures. Current is also induced in sedimentary rock creating secondary waves that propagate back to the wellbore. The radiation pattern is electrically driven in azimuth around the wellbore. The receiving antenna is located in the null field of the radiating antenna so that the primary wave is below the thermal noise of the receiver input. By stepping the frequency through the low- and medium-frequency bands, the depth of investigation is varied, and enables electrical conductivity profiling away from the wellbore. Interpretation software has been developed for reconstructive imaging in dipping sedimentary layers. Because electrical conductivity can be related to oil/water saturation, both fractures and fluids can be mapped. Modeling suggests that swarms of fractures can be imaged and fluid type determined. This information will be useful in smart fracking and sealing. Conductivity tomography images will indicate bed dip, oil/water saturation, and map fluids. This paper will provide an overview of the technology development program.

A fast complex domain-matching pursuit algorithm and its application to deep-water gas reservoir detection

Science.gov (United States)

Zeng, Jing; Huang, Handong; Li, Huijie; Miao, Yuxin; Wen, Junxiang; Zhou, Fei

2017-12-01

The main emphasis of exploration and development is shifting from simple structural reservoirs to complex reservoirs, which all have the characteristics of complex structure, thin reservoir thickness and large buried depth. Faced with these complex geological features, hydrocarbon detection technology is a direct indication of changes in hydrocarbon reservoirs and a good approach for delimiting the distribution of underground reservoirs. It is common to utilize the time-frequency (TF) features of seismic data in detecting hydrocarbon reservoirs. Therefore, we research the complex domain-matching pursuit (CDMP) method and propose some improvements. First is the introduction of a scale parameter, which corrects the defect that atomic waveforms only change with the frequency parameter. Its introduction not only decomposes seismic signal with high accuracy and high efficiency but also reduces iterations. We also integrate jumping search with ergodic search to improve computational efficiency while maintaining the reasonable accuracy. Then we combine the improved CDMP with the Wigner-Ville distribution to obtain a high-resolution TF spectrum. A one-dimensional modeling experiment has proved the validity of our method. Basing on the low-frequency domain reflection coefficient in fluid-saturated porous media, we finally get an approximation formula for the mobility attributes of reservoir fluid. This approximation formula is used as a hydrocarbon identification factor to predict deep-water gas-bearing sand of the M oil field in the South China Sea. The results are consistent with the actual well test results and our method can help inform the future exploration of deep-water gas reservoirs.

Monitoring reservoir response to earthquakes and fluid extraction, Salton Sea geothermal field, California

Science.gov (United States)

Taira, Taka’aki; Nayak, Avinash; Brenguier, Florent; Manga, Michael

2018-01-01

Continuous monitoring of in situ reservoir responses to stress transients provides insights into the evolution of geothermal reservoirs. By exploiting the stress dependence of seismic velocity changes, we investigate the temporal evolution of the reservoir stress state of the Salton Sea geothermal field (SSGF), California. We find that the SSGF experienced a number of sudden velocity reductions (~0.035 to 0.25%) that are most likely caused by openings of fractures due to dynamic stress transients (as small as 0.08 MPa and up to 0.45 MPa) from local and regional earthquakes. Depths of velocity changes are estimated to be about 0.5 to 1.5 km, similar to the depths of the injection and production wells. We derive an empirical in situ stress sensitivity of seismic velocity changes by relating velocity changes to dynamic stresses. We also observe systematic velocity reductions (0.04 to 0.05%) during earthquake swarms in mid-November 2009 and late-December 2010. On the basis of volumetric static and dynamic stress changes, the expected velocity reductions from the largest earthquakes with magnitude ranging from 3 to 4 in these swarms are less than 0.02%, which suggests that these earthquakes are likely not responsible for the velocity changes observed during the swarms. Instead, we argue that velocity reductions may have been induced by poroelastic opening of fractures due to aseismic deformation. We also observe a long-term velocity increase (~0.04%/year) that is most likely due to poroelastic contraction caused by the geothermal production. Our observations demonstrate that seismic interferometry provides insights into in situ reservoir response to stress changes. PMID:29326977

Monitoring reservoir response to earthquakes and fluid extraction, Salton Sea geothermal field, California.

Science.gov (United States)

Taira, Taka'aki; Nayak, Avinash; Brenguier, Florent; Manga, Michael

2018-01-01

Continuous monitoring of in situ reservoir responses to stress transients provides insights into the evolution of geothermal reservoirs. By exploiting the stress dependence of seismic velocity changes, we investigate the temporal evolution of the reservoir stress state of the Salton Sea geothermal field (SSGF), California. We find that the SSGF experienced a number of sudden velocity reductions (~0.035 to 0.25%) that are most likely caused by openings of fractures due to dynamic stress transients (as small as 0.08 MPa and up to 0.45 MPa) from local and regional earthquakes. Depths of velocity changes are estimated to be about 0.5 to 1.5 km, similar to the depths of the injection and production wells. We derive an empirical in situ stress sensitivity of seismic velocity changes by relating velocity changes to dynamic stresses. We also observe systematic velocity reductions (0.04 to 0.05%) during earthquake swarms in mid-November 2009 and late-December 2010. On the basis of volumetric static and dynamic stress changes, the expected velocity reductions from the largest earthquakes with magnitude ranging from 3 to 4 in these swarms are less than 0.02%, which suggests that these earthquakes are likely not responsible for the velocity changes observed during the swarms. Instead, we argue that velocity reductions may have been induced by poroelastic opening of fractures due to aseismic deformation. We also observe a long-term velocity increase (~0.04%/year) that is most likely due to poroelastic contraction caused by the geothermal production. Our observations demonstrate that seismic interferometry provides insights into in situ reservoir response to stress changes.

Some aspects of the role of intergranular fluids in the compositional ...

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

fluid, solubility in the fluid and mass balance between the various reservoirs. The model ... It is shown that a coupling of thermodynamics and kinetics controls the evolution of the system and the ...... systems. AGU Fall Meeting; EOS 78 F833.

Effects of hydraulic frac fluids and formation waters on groundwater microbial communities

Science.gov (United States)

Krueger, Martin; Jimenez, Nuria

2017-04-01

Shale gas is being considered as a complementary energy resource to other fossil fuels. Its exploitation requires using advanced drilling techniques and hydraulic stimulation (fracking). During fracking operations, large amounts of fluids (fresh water, proppants and chemicals) are injected at high pressures into the formations, to create fractures and fissures, and thus to release gas from the source rock into the wellbore. The injected fluid partly remains in the formation, while up to 40% flows back to the surface, together with reservoir waters, sometimes containing dissolved hydrocarbons, high salt concentrations, etc. The aim of our study was to investigate the potential impacts of frac or geogenic chemicals, frac fluid, formation water or flowback on groudnwater microbial communities. Laboratory experiments under in situ conditions (i.e. at in situ temperature, high pressure) were conducted using groundwater samples from three different locations. Series of microcosms containing R2 broth medium or groundwater spiked with either single frac chemicals (including biocides), frac fluids, artificial reservoir water, NaCl, or different mixtures of reservoir water and frac fluid (to simulate flowback) were incubated in the dark. Controls included non-amended and non-inoculated microcosms. Classical microbiological methods and molecular analyses were used to assess changes in the microbial abundance, community structure and function in response to the different treatments. Microbial communities were quite halotolerant and their growth benefited from low concentrations of reservoir waters or salt, but they were negatively affected by higher concentrations of formation waters, salt, biocides or frac fluids. Changes on the microbial community structure could be detected by T-RFLP. Single frac components like guar gum or choline chloride were used as substrates, while others like triethanolamine or light oil distillate hydrogenated prevented microbial growth in

Detecting subsurface fluid leaks in real-time using injection and production rates

Science.gov (United States)

Singh, Harpreet; Huerta, Nicolas J.

2017-12-01

CO2 injection into geologic formations for either enhanced oil recovery or carbon storage introduces a risk for undesired fluid leakage into overlying groundwater or to the surface. Despite decades of subsurface CO2 production and injection, the technologies and methods for detecting CO2 leaks are still costly and prone to large uncertainties. This is especially true for pressure-based monitoring methods, which require the use of simplified geological and reservoir flow models to simulate the pressure behavior as well as background noise affecting pressure measurements. In this study, we propose a method to detect the time and volume of fluid leakage based on real-time measurements of well injection and production rates. The approach utilizes analogies between fluid flow and capacitance-resistance modeling. Unlike other leak detection methods (e.g. pressure-based), the proposed method does not require geological and reservoir flow models to simulate the behavior that often carry significant sources of uncertainty; therefore, with our approach the leak can be detected with greater certainty. The method can be applied to detect when a leak begins by tracking a departure in fluid production rate from the expected pattern. The method has been tuned to detect the effect of boundary conditions and fluid compressibility on leakage. To highlight the utility of this approach we use our method to detect leaks for two scenarios. The first scenario simulates a fluid leak from the storage formation into an above-zone monitoring interval. The second scenario simulates intra-reservoir migration between two compartments. We illustrate this method to detect fluid leakage in three different reservoirs with varying levels of geological and structural complexity. The proposed leakage detection method has three novelties: i) requires only readily-available data (injection and production rates), ii) accounts for fluid compressibility and boundary effects, and iii) in addition to

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

Effect of chaotic movements of nanoparticles for nanofluid heat transfer augmentation by molecular dynamics simulation

International Nuclear Information System (INIS)

Cui, Wenzheng; Shen, Zhaojie; Yang, Jianguo; Wu, Shaohua

2015-01-01

Through Molecular Dynamics simulation, the chaotic movements of nanoparticles in base fluid are investigated. Based on the simulated results of translational and rotational velocities of nanoparticles, the effect of nanoparticle movements for heat transfer in nanofluids is discussed. Furthermore, the influence of nanoparticle movements for the base fluid is studied. The fluid near a nanoparticle is divided into three levels: (1) absorption layer, (2) rotating fluid, and (3) spherical existential space, or called rotating fluid element. And the microscopic structure of nanofluid which is composed of countless rotating fluid elements is proposed. - Highlights: • The orders of magnitude of translational and rotational motions for nanoparticles are given. • The microscopic structure around a nanoparticle is proposed. • Mechanisms of heat transfer enhancement in nanofluids are discussed

Mobility Effect on Poroelastic Seismic Signatures in Partially Saturated Rocks With Applications in Time-Lapse Monitoring of a Heavy Oil Reservoir

Science.gov (United States)

Zhao, Luanxiao; Yuan, Hemin; Yang, Jingkang; Han, De-hua; Geng, Jianhua; Zhou, Rui; Li, Hui; Yao, Qiuliang

2017-11-01

Conventional seismic analysis in partially saturated rocks normally lays emphasis on estimating pore fluid content and saturation, typically ignoring the effect of mobility, which decides the ability of fluids moving in the porous rocks. Deformation resulting from a seismic wave in heterogeneous partially saturated media can cause pore fluid pressure relaxation at mesoscopic scale, thereby making the fluid mobility inherently associated with poroelastic reflectivity. For two typical gas-brine reservoir models, with the given rock and fluid properties, the numerical analysis suggests that variations of patchy fluid saturation, fluid compressibility contrast, and acoustic stiffness of rock frame collectively affect the seismic reflection dependence on mobility. In particular, the realistic compressibility contrast of fluid patches in shallow and deep reservoir environments plays an important role in determining the reflection sensitivity to mobility. We also use a time-lapse seismic data set from a Steam-Assisted Gravity Drainage producing heavy oil reservoir to demonstrate that mobility change coupled with patchy saturation possibly leads to seismic spectral energy shifting from the baseline to monitor line. Our workflow starts from performing seismic spectral analysis on the targeted reflectivity interface. Then, on the basis of mesoscopic fluid pressure diffusion between patches of steam and heavy oil, poroelastic reflectivity modeling is conducted to understand the shift of the central frequency toward low frequencies after the steam injection. The presented results open the possibility of monitoring mobility change of a partially saturated geological formation from dissipation-related seismic attributes.

An overview of iterative coupling between geomechanical deformation and reservoir flow

International Nuclear Information System (INIS)

Tran, D.; Nghiem, L.; Buchanan, L.

2005-01-01

The coupling of a reservoir simulator to a geomechanics module has been widely applied in the petroleum industry. In a traditional reservoir simulator, subsidence can be estimated by a relatively simple formula. In a coupled simulator, flow is strongly affected by stresses and strains through porosity. Stress-dependence is ignored completely in conventional simulators, and solutions obtained from them cannot give accurate results if a stress sensitive reservoir is under consideration. In addition, thermal stresses cannot be accounted for. An iterative coupling method was presented. The basic equations for fluid flow in a porous medium consist of the equation of mass conservation, the equation of energy conservation, Darcy's law and equations of state depicting fluid characteristics. A continuum approach was used to develop the conservative equations. Material was assumed to be homogenous, isotropic and symmetric. Three test examples were used to illustrate the validity of geomechanics in reservoir simulation. The first example illustrated the difference in heave when a linear thermo-elastic constitutive model and a thermo-elastoplastic model were used. In the second example, a plastic cap model and a no-cap model were used to illustrate differences in porosity calculations. The 2 examples demonstrated that displacements and porosity calculations depend on the stress response and on the constitutive law of a material. In the third example a pseudo dilation-recompaction model showed a displacement calculation that was comparable with calculations obtained with 2-way coupling. The example illustrated the application of one-way coupling in scenarios where rigorous geomechanics calculations of subsidence are performed without the constraint of feeding back the information to a reservoir simulator. 22 refs., 13 figs

MeProRisk - a Joint Venture for Minimizing Risk in Geothermal Reservoir Development

Science.gov (United States)

Clauser, C.; Marquart, G.

2009-12-01

Exploration and development of geothermal reservoirs for the generation of electric energy involves high engineering and economic risks due to the need for 3-D geophysical surface surveys and deep boreholes. The MeProRisk project provides a strategy guideline for reducing these risks by combining cross-disciplinary information from different specialists: Scientists from three German universities and two private companies contribute with new methods in seismic modeling and interpretation, numerical reservoir simulation, estimation of petrophysical parameters, and 3-D visualization. The approach chosen in MeProRisk consists in considering prospecting and developing of geothermal reservoirs as an iterative process. A first conceptual model for fluid flow and heat transport simulation can be developed based on limited available initial information on geology and rock properties. In the next step, additional data is incorporated which is based on (a) new seismic interpretation methods designed for delineating fracture systems, (b) statistical studies on large numbers of rock samples for estimating reliable rock parameters, (c) in situ estimates of the hydraulic conductivity tensor. This results in a continuous refinement of the reservoir model where inverse modelling of fluid flow and heat transport allows infering the uncertainty and resolution of the model at each iteration step. This finally yields a calibrated reservoir model which may be used to direct further exploration by optimizing additional borehole locations, estimate the uncertainty of key operational and economic parameters, and optimize the long-term operation of a geothermal resrvoir.

Simulating cold production by a coupled reservoir-geomechanics model with sand erosion

Energy Technology Data Exchange (ETDEWEB)

Wang, Y.; Xue, S. [Petro-Geotech Inc., Calgary, AB (Canada)

2002-06-01

This paper presents a newly developed fully coupled reservoir-geomechanics model with sand erosion. Sand production occurs during aggressive production induced by the impact of viscous fluid flow and the in situ stress concentration near a wellbore, as well as by perforation tips in poorly consolidated formations. This compromises oil production, increases well completion costs, and reduces the life cycles of equipment down hole and on the surface. The proposed model can be used for sand production studies in conventional oil/gas reservoirs such as the North Sea as well as in heavy oil reservoirs such as in northwestern Canada. Instead of generating a high permeability network in reservoirs, the enhanced oil production is determined by the increase in the effective wellbore radius. This paper presents the general model. A detailed study on the capillary pressure and the impact of multiphase flow on sanding and erosion will be conducted at a later date. It appears that 2 phase flow can be important to elastoplasticity if no significant sand erosion has occurred. It was determined that high porosity is induced by erosion and capillary pressure. Two phase flow can be important when the built-up drag force carries sand-fluid slurry into the well. It is concluded that viscosity and flow velocity can help estimate the slurry transport, sand rate and enhanced oil production. 22 refs., 3 tabs., 11 figs.

Differential Muon Tomography to Continuously Monitor Changes in the Composition of Subsurface Fluids

Science.gov (United States)

Coleman, Max; Kudryavtsev, Vitaly A.; Spooner, Neil J.; Fung, Cora; Gluyas, John

2013-01-01

Muon tomography has been used to seek hidden chambers in Egyptian pyramids and image subsurface features in volcanoes. It seemed likely that it could be used to image injected, supercritical carbon dioxide as it is emplaced in porous geological structures being used for carbon sequestration, and also to check on subsequent leakage. It should work equally well in any other application where there are two fluids of different densities, such as water and oil, or carbon dioxide and heavy oil in oil reservoirs. Continuous monitoring of movement of oil and/or flood fluid during enhanced oil recovery activities for managing injection is important for economic reasons. Checking on leakage for geological carbon storage is essential both for safety and for economic purposes. Current technology (for example, repeat 3D seismic surveys) is expensive and episodic. Muons are generated by high- energy cosmic rays resulting from supernova explosions, and interact with gas molecules in the atmosphere. This innovation has produced a theoretical model of muon attenuation in the thickness of rock above and within a typical sandstone reservoir at a depth of between 1.00 and 1.25 km. Because this first simulation was focused on carbon sequestration, the innovators chose depths sufficient for the pressure there to ensure that the carbon dioxide would be supercritical. This innovation demonstrates for the first time the feasibility of using the natural cosmic-ray muon flux to generate continuous tomographic images of carbon dioxide in a storage site. The muon flux is attenuated to an extent dependent on, amongst other things, the density of the materials through which it passes. The density of supercritical carbon dioxide is only three quarters that of the brine in the reservoir that it displaces. The first realistic simulations indicate that changes as small as 0.4% in the storage site bulk density could be detected (equivalent to 7% of the porosity, in this specific case). The initial

Thermal Fluid Engineering

International Nuclear Information System (INIS)

Jang, Byeong Ju

1984-01-01

This book is made up of 5 chapters. They are fluid mechanics, fluid machines, Industrial thermodynamics, steam boiler and steam turbine. It introduces hydrostatics, basic theory of fluid movement and law of momentum. It also deals with centrifugal pump, axial flow pump, general hydraulic turbine, and all phenomena happening in the pump. It covers the law of thermodynamics, perfect gas, properties of steam, and flow of gas and steam and water tube boiler. Lastly it explains basic format, theory, loss and performance as well as principle part of steam turbine.

Petroacoustic Modelling of Heterolithic Sandstone Reservoirs: A Novel Approach to Gassmann Modelling Incorporating Sedimentological Constraints and NMR Porosity data

Science.gov (United States)

Matthews, S.; Lovell, M.; Davies, S. J.; Pritchard, T.; Sirju, C.; Abdelkarim, A.

2012-12-01

Heterolithic or 'shaly' sandstone reservoirs constitute a significant proportion of hydrocarbon resources. Petroacoustic models (a combination of petrophysics and rock physics) enhance the ability to extract reservoir properties from seismic data, providing a connection between seismic and fine-scale rock properties. By incorporating sedimentological observations these models can be better constrained and improved. Petroacoustic modelling is complicated by the unpredictable effects of clay minerals and clay-sized particles on geophysical properties. Such effects are responsible for erroneous results when models developed for "clean" reservoirs - such as Gassmann's equation (Gassmann, 1951) - are applied to heterolithic sandstone reservoirs. Gassmann's equation is arguably the most popular petroacoustic modelling technique in the hydrocarbon industry and is used to model elastic effects of changing reservoir fluid saturations. Successful implementation of Gassmann's equation requires well-constrained drained rock frame properties, which in heterolithic sandstones are heavily influenced by reservoir sedimentology, particularly clay distribution. The prevalent approach to categorising clay distribution is based on the Thomas - Stieber model (Thomas & Stieber, 1975), this approach is inconsistent with current understanding of 'shaly sand' sedimentology and omits properties such as sorting and grain size. The novel approach presented here demonstrates that characterising reservoir sedimentology constitutes an important modelling phase. As well as incorporating sedimentological constraints, this novel approach also aims to improve drained frame moduli estimates through more careful consideration of Gassmann's model assumptions and limitations. A key assumption of Gassmann's equation is a pore space in total communication with movable fluids. This assumption is often violated by conventional applications in heterolithic sandstone reservoirs where effective porosity, which

Total phosphorus recovery in flowback fluids after gelled hydrocarbon fracturing fluid treatments

Energy Technology Data Exchange (ETDEWEB)

Fyten, G.; Houle, P.; Taylor, R.S. [Halliburton Energy Services, Calgary, AB (Canada); Stemler, P.S. [Petro-Canada Oil and Gas Inc., Calgary, AB (Canada); Lemieux, A. [Omnicon Consultants Inc., Calgary, AB (Canada)

2006-07-01

Carbon dioxide miscible hydrocarbon fracturing fluids are used in unconventional gas reservoirs such as tight gas, shale gas, and coalbed methane. These fracturing fluids address phase trapping concerns by using oil-based fracturing fluid technology for use in reservoirs that are water sensitive. This paper addressed the problem of refinery tower fouling caused by volatile phosphorous components found in phosphate ester oil gellants. In order to address costly unplanned refinery shutdowns, a maximum 0.5 ppm volatile phosphorus in crude specification has been proposed. However, this specification is based on average concentrations of phosphorus added to the oil to gel it. The specification also falsely assumes that the oil is phosphorus free to begin with. The authors noted that refinery tower fouling is actually the result of total phosphorus throughput rather than peak concentrations at any one point. This paper focused on the total phosphorus recovery in addition to peak concentrations. It also examined what percentage of the total recovered phosphorus is in fact volatile, since this is the material that plugs the trays. The total per cent recovery of phosphorus originally added as phosphorus based gellant was examined along with the total percent recovery of volatile phosphorus as a function of total phosphorus. The phosphorus concentrations in both new and reused fracturing fluids before addition of gellants was also examined along with the potential explanations for phosphorus concentrations higher than those originally added. It was shown that the first 50 per cent of a hydraulic fracturing fluid flowback can result in recovery of greater than or less than the amount of phosphorus added to that portion of the fracturing fluid. The initial high concentrations of total and volatile phosphorus are greater than the phosphorus concentrations inherent in the system. Therefore, as flowback continues, there would be a rapid decline in the concentration of phosphorus

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.

Seismic spectral decomposition and analysis based on Wigner–Ville distribution for sandstone reservoir characterization in West Sichuan depression

International Nuclear Information System (INIS)

Wu, Xiaoyang; Liu, Tianyou

2010-01-01

Reflections from a hydrocarbon-saturated zone are generally expected to have a tendency to be low frequency. Previous work has shown the application of seismic spectral decomposition for low-frequency shadow detection. In this paper, we further analyse the characteristics of spectral amplitude in fractured sandstone reservoirs with different fluid saturations using the Wigner–Ville distribution (WVD)-based method. We give a description of the geometric structure of cross-terms due to the bilinear nature of WVD and eliminate cross-terms using smoothed pseudo-WVD (SPWVD) with time- and frequency-independent Gaussian kernels as smoothing windows. SPWVD is finally applied to seismic data from West Sichuan depression. We focus our study on the comparison of SPWVD spectral amplitudes resulting from different fluid contents. It shows that prolific gas reservoirs feature higher peak spectral amplitude at higher peak frequency, which attenuate faster than low-quality gas reservoirs and dry or wet reservoirs. This can be regarded as a spectral attenuation signature for future exploration in the study area

Unconventional Tight Reservoirs Characterization with Nuclear Magnetic Resonance

Science.gov (United States)

Santiago, C. J. S.; Solatpour, R.; Kantzas, A.

2017-12-01

The increase in tight reservoir exploitation projects causes producing many papers each year on new, modern, and modified methods and techniques on estimating characteristics of these reservoirs. The most ambiguous of all basic reservoir property estimations deals with permeability. One of the logging methods that is advertised to predict permeability but is always met by skepticism is Nuclear Magnetic Resonance (NMR). The ability of NMR to differentiate between bound and movable fluids and providing porosity increased the capability of NMR as a permeability prediction technique. This leads to a multitude of publications and the motivation of a review paper on this subject by Babadagli et al. (2002). The first part of this presentation is dedicated to an extensive review of the existing correlation models for NMR based estimates of tight reservoir permeability to update this topic. On the second part, the collected literature information is used to analyze new experimental data. The data are collected from tight reservoirs from Canada, the Middle East, and China. A case study is created to apply NMR measurement in the prediction of reservoir characterization parameters such as porosity, permeability, cut-offs, irreducible saturations etc. Moreover, permeability correlations are utilized to predict permeability. NMR experiments were conducted on water saturated cores. NMR T2 relaxation times were measured. NMR porosity, the geometric mean relaxation time (T2gm), Irreducible Bulk Volume (BVI), and Movable Bulk Volume (BVM) were calculated. The correlation coefficients were computed based on multiple regression analysis. Results are cross plots of NMR permeability versus the independently measured Klinkenberg corrected permeability. More complicated equations are discussed. Error analysis of models is presented and compared. This presentation is beneficial in understanding existing tight reservoir permeability models. The results can be used as a guide for choosing

Tectonic environment and cause of earthquakes in the Three Gorges reservoir area

Directory of Open Access Journals (Sweden)

Li Qiang

2011-02-01

Full Text Available Seismotectonics in the Three Gorges reservoir area is investigated by using the P-wave tomography with earthquakes that occurred before the impoundment of the reservoir. The result indicates that most of these events occurred in or around the velocity-gradient belts between high-velocity and low-velocity anomalies. These belts have similar characteristics to bured-fault zones. Stresses generated by movement of partially molten upper-mantle materials and thermal stress may have jointly contributed to the seismic activities along the faults and such buried faults, and possibly activated new earthquake ruptures.

Direct hydrocarbon exploration and gas reservoir development technology

Energy Technology Data Exchange (ETDEWEB)

Kwak, Young Hoon; Oh, Jae Ho; Jeong, Tae Jin [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of); and others

1995-12-01

In order to enhance the capability of petroleum exploration and development techniques, three year project (1994 - 1997) was initiated on the research of direct hydrocarbon exploration and gas reservoir development. This project consists of four sub-projects. (1) Oil(Gas) - source rock correlation technique: The overview of bio-marker parameters which are applicable to hydrocarbon exploration has been illustrated. Experimental analysis of saturated hydrocarbon and bio-markers of the Pohang E and F core samples has been carried out. (2) Study on surface geochemistry and microbiology for hydrocarbon exploration: the test results of the experimental device for extraction of dissolved gases from water show that the device can be utilized for the gas geochemistry of water. (3) Development of gas and gas condensate reservoirs: There are two types of reservoir characterization. For the reservoir formation characterization, calculation of conditional simulation was compared with that of unconditional simulation. In the reservoir fluid characterization, phase behavior calculations revealed that the component grouping is more important than the increase of number of components. (4) Numerical modeling of seismic wave propagation and full waveform inversion: Three individual sections are presented. The first one is devoted to the inversion theory in general sense. The second and the third sections deal with the frequency domain pseudo waveform inversion of seismic reflection data and refraction data respectively. (author). 180 refs., 91 figs., 60 tabs.

Fluid injection and induced seismicity

Science.gov (United States)

Kendall, Michael; Verdon, James

2016-04-01

The link between fluid injection, or extraction, and induced seismicity has been observed in reservoirs for many decades. In fact spatial mapping of low magnitude events is routinely used to estimate a stimulated reservoir volume. However, the link between subsurface fluid injection and larger felt seismicity is less clear and has attracted recent interest with a dramatic increase in earthquakes associated with the disposal of oilfield waste fluids. In a few cases, hydraulic fracturing has also been linked to induced seismicity. Much can be learned from past case-studies of induced seismicity so that we can better understand the risks posed. Here we examine 12 case examples and consider in particular controls on maximum event size, lateral event distributions, and event depths. Our results suggest that injection volume is a better control on maximum magnitude than past, natural seismicity in a region. This might, however, simply reflect the lack of baseline monitoring and/or long-term seismic records in certain regions. To address this in the UK, the British Geological Survey is leading the deployment of monitoring arrays in prospective shale gas areas in Lancashire and Yorkshire. In most cases, seismicity is generally located in close vicinity to the injection site. However, in some cases, the nearest events are up to 5km from the injection point. This gives an indication of the minimum radius of influence of such fluid injection projects. The most distant events are never more than 20km from the injection point, perhaps implying a maximum radius of influence. Some events are located in the target reservoir, but most occur below the injection depth. In fact, most events lie in the crystalline basement underlying the sedimentary rocks. This suggests that induced seismicity may not pose a leakage risk for fluid migration back to the surface, as it does not impact caprock integrity. A useful application for microseismic data is to try and forecast induced seismicity

The fluid mechanics of scleral buckling surgery for the repair of retinal detachment.

Science.gov (United States)

Foster, William Joseph; Dowla, Nadia; Joshi, Saurabh Y; Nikolaou, Michael

2010-01-01

Scleral buckling is a common surgical technique used to treat retinal detachments that involves suturing a radial or circumferential silicone element on the sclera. Although this procedure has been performed since the 1960s, and there is a reasonable experimental model of retinal detachment, there is still debate as to how this surgery facilitates the re-attachment of the retina. Finite element calculations using the COMSOL Multiphysics system are utilized to explain the influence of the scleral buckle on the flow of sub-retinal fluid in a physical model of retinal detachment. We found that, by coupling fluid mechanics with structural mechanics, laminar fluid flow and the Bernoulli effect are necessary for a physically consistent explanation of retinal reattachment. Improved fluid outflow and retinal reattachment are found with low fluid viscosity and rapid eye movements. A simulation of saccadic eye movements was more effective in removing sub-retinal fluid than slower, reading speed, eye movements in removing subretinal fluid. The results of our simulations allow us to explain the physical principles behind scleral buckling surgery and provide insight that can be utilized clinically. In particular, we find that rapid eye movements facilitate more rapid retinal reattachment. This is contradictory to the conventional wisdom of attempting to minimize eye movements.

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.

Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs

Energy Technology Data Exchange (ETDEWEB)

Michael Batzle

2006-04-30

During this last period of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we finalized integration of rock physics, well log analysis, seismic processing, and forward modeling techniques. Most of the last quarter was spent combining the results from the principal investigators and come to some final conclusions about the project. Also much of the effort was directed towards technology transfer through the Direct Hydrocarbon Indicators mini-symposium at UH and through publications. As a result we have: (1) Tested a new method to directly invert reservoir properties, water saturation, Sw, and porosity from seismic AVO attributes; (2) Constrained the seismic response based on fluid and rock property correlations; (3) Reprocessed seismic data from Ursa field; (4) Compared thin layer property distributions and averaging on AVO response; (5) Related pressures and sorting effects on porosity and their influence on DHI's; (6) Examined and compared gas saturation effects for deep and shallow reservoirs; (7) Performed forward modeling using geobodies from deepwater outcrops; (8) Documented velocities for deepwater sediments; (9) Continued incorporating outcrop descriptive models in seismic forward models; (10) Held an open DHI symposium to present the final results of the project; (11) Relations between Sw, porosity, and AVO attributes; (12) Models of Complex, Layered Reservoirs; and (14) Technology transfer Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and

Ultrasound directed self-assembly of three-dimensional user-specified patterns of particles in a fluid medium

Science.gov (United States)

Prisbrey, M.; Greenhall, J.; Guevara Vasquez, F.; Raeymaekers, B.

2017-01-01

We use ultrasound directed self-assembly to organize particles dispersed in a fluid medium into a three-dimensional (3D) user-specified pattern. The technique employs ultrasound transducers that line the boundary of a fluid reservoir to create a standing ultrasound wave field. The acoustic radiation force associated with the wave field drives particles dispersed in the fluid medium into organized patterns, assuming that the particles are much smaller than the wavelength and do not interact with each other. We have theoretically derived a direct solution method to calculate the ultrasound transducer operating parameters that are required to assemble a user-specified 3D pattern of particles in a fluid reservoir of arbitrary geometry. We formulate the direct solution method as a constrained optimization problem that reduces to eigendecomposition. We experimentally validate the solution method by assembling 3D patterns of carbon nanoparticles in a water reservoir and observe good quantitative agreement between theory and experiment. Additionally, we demonstrate the versatility of the solution method by simulating ultrasound directed self-assembly of complex 3D patterns of particles. The method works for any 3D simple, closed fluid reservoir geometry in combination with any arrangement of ultrasound transducers and enables employing ultrasound directed self-assembly in a myriad of engineering applications, including biomedical and materials fabrication processes.

Hydraulic Fracturing and Production Optimization in Eagle Ford Shale Using Coupled Geomechanics and Fluid Flow Model

Science.gov (United States)

Suppachoknirun, Theerapat; Tutuncu, Azra N.

2017-12-01

With increasing production from shale gas and tight oil reservoirs, horizontal drilling and multistage hydraulic fracturing processes have become a routine procedure in unconventional field development efforts. Natural fractures play a critical role in hydraulic fracture growth, subsequently affecting stimulated reservoir volume and the production efficiency. Moreover, the existing fractures can also contribute to the pressure-dependent fluid leak-off during the operations. Hence, a reliable identification of the discrete fracture network covering the zone of interest prior to the hydraulic fracturing design needs to be incorporated into the hydraulic fracturing and reservoir simulations for realistic representation of the in situ reservoir conditions. In this research study, an integrated 3-D fracture and fluid flow model have been developed using a new approach to simulate the fluid flow and deliver reliable production forecasting in naturally fractured and hydraulically stimulated tight reservoirs. The model was created with three key modules. A complex 3-D discrete fracture network model introduces realistic natural fracture geometry with the associated fractured reservoir characteristics. A hydraulic fracturing model is created utilizing the discrete fracture network for simulation of the hydraulic fracture and flow in the complex discrete fracture network. Finally, a reservoir model with the production grid system is used allowing the user to efficiently perform the fluid flow simulation in tight formations with complex fracture networks. The complex discrete natural fracture model, the integrated discrete fracture model for the hydraulic fracturing, the fluid flow model, and the input dataset have been validated against microseismic fracture mapping and commingled production data obtained from a well pad with three horizontal production wells located in the Eagle Ford oil window in south Texas. Two other fracturing geometries were also evaluated to optimize

Polymer Drilling Fluid with Micron-Grade Cenosphere for Deep Coal Seam

Directory of Open Access Journals (Sweden)

Peng Xu

2015-01-01

Full Text Available Traditional shallow coal seam uses clean water, solid-free system, and foam system as drilling fluid, while they are not suitable for deep coal seam drilling due to mismatching density, insufficient bearing capacity, and poor reservoir protection effect. According to the existing problems of drilling fluid, micron-grade cenosphere with high bearing capacity and ultralow true density is selected as density regulator; it, together with polymer “XC + CMC” and some other auxiliary agents, is jointly used to build micron-grade polymer drilling fluid with cenosphere which is suitable for deep coal seam. Basic performance test shows that the drilling fluid has good rheological property, low filtration loss, good density adjustability, shear thinning, and thixotropy; besides, drilling fluid flow is in line with the power law rheological model. Compared with traditional drilling fluid, dispersion stability basically does not change within 26 h; settlement stability evaluated with two methods only shows a small amount of change; permeability recovery rate evaluated with Qinshui Basin deep coal seam core exceeds 80%. Polymer drilling fluid with cenosphere provides a new thought to solve the problem of drilling fluid density and pressure for deep coal seam drilling and also effectively improves the performance of reservoir protection ability.

Electrokinetic effects and fluid permeability

International Nuclear Information System (INIS)

Berryman, J.G.

2003-01-01

Fluid permeability of porous media depends mainly on connectivity of the pore space and two physical parameters: porosity and a pertinent length-scale parameter. Electrical imaging methods typically establish connectivity and directly measure electrical conductivity, which can then often be related to porosity by Archie's law. When electrical phase measurements are made in addition to the amplitude measurements, information about the pertinent length scale can then be obtained. Since fluid permeability controls the ability to flush unwanted fluid contaminants from the subsurface, inexpensive maps of permeability could improve planning strategies for remediation efforts. Detailed knowledge of fluid permeability is also important for oil field exploitation, where knowledge of permeability distribution in three dimensions is a common requirement for petroleum reservoir simulation and analysis, as well as for estimates on the economics of recovery

Rock Physics of Reservoir Rocks with Varying Pore Water Saturation and Pore Water Salinity

DEFF Research Database (Denmark)

Katika, Konstantina

experiments, the rock is subjected to high external stresses that resemble the reservoir stresses; 2) the fluid distribution within the pore space changes during the flow through experiments and wettability alterations may occur; 3) different ions, present in the salt water injected in the core, interact......Advanced waterflooding (injection of water with selective ions in reservoirs) is a method of enhanced oil recovery (EOR) that has attracted the interest of oil and gas companies that exploit the Danish oil and gas reservoirs. This method has been applied successfully in oil reservoirs...... and in the Smart Water project performed in a laboratory scale in order to evaluate the EOR processes in selected core plugs. A major step towards this evaluation is to identify the composition of the injected water that leads to increased oil recovery in reservoirs and to define changes in the petrophysical...

Numerical simulation of single-phase and multiphase non-Darcy flowin porous and fractured reservoirs

Energy Technology Data Exchange (ETDEWEB)

Wu, Yu-Shu

2000-06-02

A numerical method as well as a theoretical study of non-Darcy fluid flow of through porous and fractured reservoirs is described. The non-Darcy flow is handled in a three-dimensional, multiphase flow reservoir simulator, while the model formulation incorporates the Forchheimer equation for describing single-phase or multiphase non-Darcy flow and displacement. The numerical scheme has been verified by comparing its results against those of analytical methods. Numerical solutions are used to obtain some insight into the physics of non-Darcy flow and displacement in reservoirs. In addition, several type curves are provided for well-test analyses of non-Darcy flow to demonstrate a methodology for modeling this type of flow in porous and fractured rocks, including flow in geothermal reservoirs.

A Methodology to Integrate Magnetic Resonance and Acoustic Measurements for Reservoir Characterization

Energy Technology Data Exchange (ETDEWEB)

Parra, Jorge O.; Hackert, Chris L.; Collier, Hughbert A.; Bennett, Michael

2002-01-29

The objective of this project was to develop an advanced imaging method, including pore scale imaging, to integrate NMR techniques and acoustic measurements to improve predictability of the pay zone in hydrocarbon reservoirs. This is accomplished by extracting the fluid property parameters using NMR laboratory measurements and the elastic parameters of the rock matrix from acoustic measurements to create poroelastic models of different parts of the reservoir. Laboratory measurement techniques and core imaging are being linked with a balanced petrographical analysis of the core and theoretical model.

Reservoir characterization using production data and time-lapse seismic data

Energy Technology Data Exchange (ETDEWEB)

Dadashpour, Mohsen

2009-12-15

The most commonly encountered, and probably the most challenging task in reservoir engineering, is to describe the reservoir accurately and efficiently. An accurate description of a reservoir is crucial to the management of production and efficiency of oil recovery. Reservoir modeling is an important step in a reservoir's future performance, which is in direct proportion to reservoir management, risk analysis and making key economic decisions. The purpose of reservoir modeling is to not only build a model that is consistent with currently available data, but to build one that gives a good prediction of its future behavior. Updating a reservoir model to behave as closely as possible to the real reservoir is called history matching, and the estimation of reservoir properties using this method is known as parameter estimation problem, which is an inversion process. Parameter estimation is a time consuming and non-unique problem with a large solution space. Saturation and pressure changes, and porosity and permeability distributions are the most common parameters to estimate in the oil industry. These parameters must be specified in every node within a petroleum reservoir simulator. These parameters will be adjusted until the model prediction data match the observation data to a sufficient degree. The solution space reduction in this project is done by adding time-lapse seismic data as a new set of dynamic data to the traditional production histories. Time-lapse (or 4D) seismic consists of two or more 3D seismic surveys shot at different calendar times. Time-lapse seismic surveys produce images at different times in a reservoir's history. The seismic response of a reservoir may change due to changes in pressure, fluid saturation and temperature. These changes in seismic images due to a variation in saturation and pressure can be used as additional observation data. Time-lapse seismic data are dynamical measurements which have a high resolution in the

Direct Use Reservoir Models - How We think They Work

Energy Technology Data Exchange (ETDEWEB)

Culver, G.

1990-01-01

The resource base for low-to-moderate temperature direct use geothermal applications is large and wide spread throughout the western United States. The models for direct use resources likely to be utilized in EPA Region IX depict fluids percolating to significant depths, being heated and convecting to the surface or near surface. The most commonly utilized resource is the fault controlled lateral leakage type. Geothermal fluids within the shallow reservoir vary in temperature and chemistry depending on the distance from the upflow zone. Regulations governing injected water chemistry compared to receiving water chemistry should take variations of chemistry into account.

Fiscal 1997 report of the verification research on geothermal prospecting technology. Theme 5-2. Development of a reservoir change prospecting method (reservoir change prediction technique (modeling support technique)); 1997 nendo chinetsu tansa gijutsu nado kensho chosa. 5-2. Choryuso hendo tansaho kaihatsu (choryuso hendo yosoku gijutsu (modeling shien gijutsu)) hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

To evaluate geothermal reservoirs in the initial stage of development, to keep stable output in service operation, and to develop a technology effective for extraction from peripheral reservoirs, study was made on a reservoir variation prediction technique, in particular, a modeling support technique. This paper describes the result in fiscal 1997. Underground temperature estimation technique using homogenization temperatures of fluid inclusions among core fault system measurement systems was applied to Wasabizawa field. The effect of stretching is important to estimate reservoir temperatures, and use of a minimum homogenization temperature of fluid inclusions in quartz was suitable. Even in the case of no quartz in hydrothermal veins, measured data of quartz (secondary fluid inclusion) in parent rocks adjacent to hydrothermal veins well agreed with measured temperature data. The developmental possibility of a new modeling support technique was confirmed enough through collection of documents and information. Based on the result, measurement equipment suitable for R and D was selected, and a measurement system was established through preliminary experiments. 39 refs., 35 figs., 6 tabs.

Time-lapse seismic waveform modelling and attribute analysis using hydromechanical models for a deep reservoir undergoing depletion

Science.gov (United States)

He, Y.-X.; Angus, D. A.; Blanchard, T. D.; Wang, G.-L.; Yuan, S.-Y.; Garcia, A.

2016-04-01

Extraction of fluids from subsurface reservoirs induces changes in pore pressure, leading not only to geomechanical changes, but also perturbations in seismic velocities and hence observable seismic attributes. Time-lapse seismic analysis can be used to estimate changes in subsurface hydromechanical properties and thus act as a monitoring tool for geological reservoirs. The ability to observe and quantify changes in fluid, stress and strain using seismic techniques has important implications for monitoring risk not only for petroleum applications but also for geological storage of CO2 and nuclear waste scenarios. In this paper, we integrate hydromechanical simulation results with rock physics models and full-waveform seismic modelling to assess time-lapse seismic attribute resolution for dynamic reservoir characterization and hydromechanical model calibration. The time-lapse seismic simulations use a dynamic elastic reservoir model based on a North Sea deep reservoir undergoing large pressure changes. The time-lapse seismic traveltime shifts and time strains calculated from the modelled and processed synthetic data sets (i.e. pre-stack and post-stack data) are in a reasonable agreement with the true earth models, indicating the feasibility of using 1-D strain rock physics transform and time-lapse seismic processing methodology. Estimated vertical traveltime shifts for the overburden and the majority of the reservoir are within ±1 ms of the true earth model values, indicating that the time-lapse technique is sufficiently accurate for predicting overburden velocity changes and hence geomechanical effects. Characterization of deeper structure below the overburden becomes less accurate, where more advanced time-lapse seismic processing and migration is needed to handle the complex geometry and strong lateral induced velocity changes. Nevertheless, both migrated full-offset pre-stack and near-offset post-stack data image the general features of both the overburden and

Compositional simulations of producing oil-gas ratio behaviour in low permeable gas condensate reservoir

OpenAIRE

Gundersen, Pål Lee

2013-01-01

Master's thesis in Petroleum engineering Gas condensate flow behaviour below the dew point in low permeable formations can make accurate fluid sampling a difficult challenge. The objective of this study was to investigate the producing oil-gas ratio behaviour in the infinite-acting period for a low permeable gas condensate reservoir. Compositional isothermal flow simulations were performed using a single-layer, radial and two-dimensional, gas condensate reservoir model with low permeabili...

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 neural 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

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

Effect of stratification on segregation in carbon dioxide miscible flooding in a water-flooded oil reservoir

International Nuclear Information System (INIS)

Bhatti, A.A.; Mahmood, S.M.; Amjad, B.

2013-01-01

Oil reservoirs are subjected to tertiary recovery by deploying any enhanced oil recovery (EOR) technique for the recovery of left over oil. Amongst many EOR methods one of the widely applied worldwide is CO/sub 2/ flooding through miscible, near miscible or immiscible displacement processes. CO/sub 2/ flooding process responds to a number of reservoir and fluid characteristics. These characteristics have strong effect on overall efficiency of the displacement process. Better understanding of the effect of different characteristics on displacement process is important to plan an efficient displacement process. In this work, the effect of stratification resulting in gravity segregation of the injected fluid is studied in an oil reservoir which is water-flooded during secondary phase of recovery. Sensitivity analysis is performed through successive simulation on Eclipse 300 (compositional) reservoir simulator. Process involves the continuous CO/sub 2/ injection in an oil reservoir with more than 1/3rd of original oil in place left after water flooding. Reservoir model with four different permeability layers is studied. Four patterns by changing the arrangement of the permeabilities of the layers are analysed. The effect of different arrangement or stratification on segregation of CO/sub 2/ and ultimately on the incremental oil recovery, is investigated. It has been observed that out of four arrangements, upward fining pattern relatively overcame the issue of the segregation of CO/sub 2/ and consequently 33% more oil with half injection volume is recovered when compared with the downward fining pattern. (author)

Stimuli Responsive/Rheoreversible Hydraulic Fracturing Fluids for Enhanced Geothermal Energy Production (Part I)

Science.gov (United States)

Fernandez, C. A.; Jung, H. B.; Shao, H.; Bonneville, A.; Heldebrant, D.; Hoyt, D.; Zhong, L.; Holladay, J.

2014-12-01

Cost-effective yet safe creation of high-permeability reservoirs inside deep crystalline bedrock is the primary challenge for the viability of enhanced geothermal systems and unconventional oil/gas recovery. Current reservoir stimulation processes utilize brute force (hydraulic pressures in the order of hundreds of bar) to create/propagate fractures in the bedrock. Such stimulation processes entail substantial economic costs ($3.3 million per reservoir as of 2011). Furthermore, the environmental impacts of reservoir stimulation are only recently being determined. Widespread concerns about the environmental contamination have resulted in a number of regulations for fracturing fluids advocating for greener fracturing processes. To reduce the costs and environmental impact of reservoir stimulation, we developed an environmentally friendly and recyclable hydraulic fracturing fluid that undergoes a controlled and large volume expansion with a simultaneous increase in viscosity triggered by CO2 at temperatures relevant for reservoir stimulation in Enhanced Geothermal System (EGS). The volume expansion, which will specifically occurs at EGS depths of interest, generates an exceptionally large mechanical stress in fracture networks of highly impermeable rock propagating fractures at effective stress an order of magnitude lower than current technology. This paper will concentrate on the presentation of this CO2-triggered expanding hydrogel formed from diluted aqueous solutions of polyallylamine (PAA). Aqueous PAA-CO2 mixtures also show significantly higher viscosities than conventional rheology modifiers at similar pressures and temperatures due to the cross-linking reaction of PAA with CO2, which was demonstrated by chemical speciation studies using in situ HP-HT 13C MAS-NMR. In addtion, PAA shows shear-thinning behavior, a critical advantage for the use of this fluid system in EGS reservoir stimulation. The high pressure/temperature experiments and their results as well

Monitoring artificially stimulated fluid movement in the Cretaceous Dakota aquifer, western Kansas

Science.gov (United States)

Macfarlane, Allen; Förster, Andrea; Merriam, Daniel; Schrötter, Jörg; Healey, John

2002-10-01

Aquifer properties can be evaluated by monitoring artificially stimulated fluid movements between wells, if the fluid is heated. Changes in the temperature profile recorded in observation wells indicate the flow path of the heated fluid, which in effect acts as a tracer. A fluid-flow experiment in the Cretaceous Dakota Formation at the Hodgeman County site, west-central Kansas, demonstrated the advantage of using the distributed optical-fiber temperature sensing method for monitoring transient temperature conditions in this hydrological application. The fluid flow in the aquifer was increased by producing water from a pumping well and injecting heated water in an injection well 13 m (43 ft) distant from the pumping well. The time-temperature series data obtained and compared with results from previous pumping tests point to interwell heterogeneity of the aquifer and to a zone in the sandstone aquifer of high hydraulic conductivity. However, the experiment would have allowed further clarification of aquifer heterogeneity and thermal properties if at least one observation well had been present between the injection and production wells. Résumé. Les caractéristiques d'un aquifère peuvent être évaluées en effectuant un suivi des mouvements du fluide stimulés artificiellement entre des puits, si le fluide est chauffé. Les variations de profils de température enregistrés dans les puits d'observation donnent des informations sur les directions d'écoulement du fluide chauffé, qui en fait se comporte comme un traceur. Réalisée dans la formation crétacée de Dakota, sur le site du Comté de Hodgeman (centre-ouest du Kansas), une expérience a démontré l'intérêt d'utiliser la méthode de détection distribuée de température par fibres optiques pour suivre les variations de température dans cette application hydrologique. L'écoulement du fluide dans l'aquifère a été favorisé en extrayant de l'eau par pompage et en injectant de l'eau chaude dans un

Assessment of myeloperoxidase activity at different force levels in gingival crevicular fluid during initial phase of orthodontic tooth movement

Directory of Open Access Journals (Sweden)

Honey Gurbaxani

2017-01-01

Full Text Available Background: Orthodontic movements promote remodeling of the alveolar bone, which is mediated by inflammatory reactions such as characterized by vascular changes and infiltration of leukocytes. Changes in the periodontium occur, depending on the magnitude, duration, and direction of applied force. These changes are often seen in the saliva and gingival fluids through the various substances secreted in them. Aim: The present study aimed to assess myeloperoxidase (MPO activity at different force levels in gingival crevicular fluid (GCF during the initial phase of orthodontic tooth movement by varying the effective force levels to 50, 75, 100, and 150 g. Materials and Methods: A total of thirty participants between the age groups of 18–25 years requiring upper first premolar extractions were included in the study. They were divided into three groups (I, II, and III of ten individuals each, again subdivided into two Subgroups A and B depending on the amount of force applied to the canine. Subgroup A of all the three groups used 150 g, whereas Subgroup B used 50, 75, and 100 g of force, respectively. GCF was collected at 2 h, 7 days, and 14 days of force application. Statistical Analysis: Paired t-test and ANOVA test were used to provide the descriptive statistics of mean optical density to detect the presence of MPO in GCF. Results and Conclusion: There was a highly significant increase in the MPO levels in the GCF at 14th day after force application which can be correlated to the onset of inflammatory reactions in the periodontium.

Flow of a stream through a reservoir

International Nuclear Information System (INIS)

Sauerwein, K.

1967-01-01

that of the bottom of the reservoir. However, the strong fluctuations between the day and night temperatures of the reservoir water produced marked rolling movements. Comparisons were made with simultaneously performed dye and salt experiments, but the four isotope experiments carried out at different seasons were found to be more suitable than the other procedures for investigating limnological processes and evaluating them quantitatively. (author)

Quantitative monitoring of gas flooding in oil-bearing reservoirs using a pulsed neutron tool

International Nuclear Information System (INIS)

Ruhovets, N.; Wyatt, D.F. Jr.

1991-01-01

This paper reports on quantitative monitoring of gas flooding in oil bearing reservoirs which is unique in that saturations of three fluids (gas, oil and water) in the effective pore space have to be determined, while in most other applications saturation behind casing is determined only for two fluids: hydrocarbons and water. A new method has been developed to monitor gas flooding of oil reservoirs. The method is based on computing two porosities: true effective (base) porosity determined before gas flooding, and apparent effective (monitor) porosity determined after gas flooding. The base porosity is determined from open and/or cased hole porosity logs run before the flooding. When open hole logs are available, the cased hole porosity logs are calibrated against open hole log. The monitor porosity is determined from one of the cased hole porosity logs, such as a neutron log or count rate ratio curve from a pulsed neutron log run after the gas flooding. The base and monitor porosities provide determination of the hydrogen index of the reservoir fluid after the flooding. This hydrogen index is then used to determine saturation of the flood agent after flooding. Water saturation after flooding can be determined from the equation which relates neutron total cross section (Σm) to volumetric constituent cross sections, using Σm values from a monitor run (after flooding)

Flow characteristic of Hijiori HDR reservoir from circulation test in 1991; Koon tantai Hijiori jikkenjo ni okeru senbu choryuso shiken (1991 nendo) kekka to ryudo kaiseki

Energy Technology Data Exchange (ETDEWEB)

Shiga, T; Hyodo, M; Shinohara, N; Takasugi, S [Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan)

1996-05-01

This paper reports one example of flow analyses on a circulation test carried out in fiscal 1991 at the Hijiori hot dry rock experimental field (Yamagata Prefecture). A fluid circulation model was proposed to simulate an HDR circulation system for a shallow reservoir (at a depth of about 1800 m) demonstrated in the circulation test by using an electric circuit network (which expresses continuity impedance in resistance and fluid storage in capacitance). Storage capacity of the reservoir was estimated by deriving time constant of the system from data of time-based change in reservoir pressure associated with transition phenomena during the circulation test. The storage capacity was estimated separately by dividing change of storage in the reservoir by change in the reservoir pressure. To derive the storage in the reservoir, a method to calculate non-recovered flows in the circulation test was utilized. The results of evaluating the reservoir capacity in the shallow reservoir using the above two independent methods were found substantially consistent. 3 refs., 6 figs., 1 tab.

Reservoir Characterization using geostatistical and numerical modeling in GIS with noble gas geochemistry

Science.gov (United States)

Vasquez, D. A.; Swift, J. N.; Tan, S.; Darrah, T. H.

2013-12-01

The integration of precise geochemical analyses with quantitative engineering modeling into an interactive GIS system allows for a sophisticated and efficient method of reservoir engineering and characterization. Geographic Information Systems (GIS) is utilized as an advanced technique for oil field reservoir analysis by combining field engineering and geological/geochemical spatial datasets with the available systematic modeling and mapping methods to integrate the information into a spatially correlated first-hand approach in defining surface and subsurface characteristics. Three key methods of analysis include: 1) Geostatistical modeling to create a static and volumetric 3-dimensional representation of the geological body, 2) Numerical modeling to develop a dynamic and interactive 2-dimensional model of fluid flow across the reservoir and 3) Noble gas geochemistry to further define the physical conditions, components and history of the geologic system. Results thus far include using engineering algorithms for interpolating electrical well log properties across the field (spontaneous potential, resistivity) yielding a highly accurate and high-resolution 3D model of rock properties. Results so far also include using numerical finite difference methods (crank-nicholson) to solve for equations describing the distribution of pressure across field yielding a 2D simulation model of fluid flow across reservoir. Ongoing noble gas geochemistry results will also include determination of the source, thermal maturity and the extent/style of fluid migration (connectivity, continuity and directionality). Future work will include developing an inverse engineering algorithm to model for permeability, porosity and water saturation.This combination of new and efficient technological and analytical capabilities is geared to provide a better understanding of the field geology and hydrocarbon dynamics system with applications to determine the presence of hydrocarbon pay zones (or

FORMATE-BASED FLUIDS: FORMULATION AND APPLICATION

Directory of Open Access Journals (Sweden)

Nediljka Gaurina-Međimurec

2008-12-01

Full Text Available Formate-based fluids has been successfully used in over hunders HPHT well operations since they introduced in field practice. They have many advantages when compared with conventional HPHT drilling and completion fluids such as: minimal formation damage, maintenance of additve properties at high temperatures, reduced hydraulic flow resistance, low potential for differential sticking, naturally lubricating, very low corrosion rates, biodegradable and pose little risk to the environment etc. Formate-based fluids can be applied during deep slim hole drilling, shale drilling, reservoir drilling, salt and gas hydrate formations drilling. The laboratory research was carried out to evaluate the rheological behavior of formate-based fluids as a function of temperature. Formate-based fluids were formulated using potassium formate brine, xanthan polymer, PAC, starch and calcium carbonate. Experimental results show that potassium formate improves the thermal stability of polymers.

EQUILGAS: Program to estimate temperatures and in situ two-phase conditions in geothermal reservoirs using three combined FT-HSH gas equilibria models

Science.gov (United States)

Barragán, Rosa María; Núñez, José; Arellano, Víctor Manuel; Nieva, David

2016-03-01

Exploration and exploitation of geothermal resources require the estimation of important physical characteristics of reservoirs including temperatures, pressures and in situ two-phase conditions, in order to evaluate possible uses and/or investigate changes due to exploitation. As at relatively high temperatures (>150 °C) reservoir fluids usually attain chemical equilibrium in contact with hot rocks, different models based on the chemistry of fluids have been developed that allow deep conditions to be estimated. Currently either in water-dominated or steam-dominated reservoirs the chemistry of steam has been useful for working out reservoir conditions. In this context, three methods based on the Fischer-Tropsch (FT) and combined H2S-H2 (HSH) mineral-gas reactions have been developed for estimating temperatures and the quality of the in situ two-phase mixture prevailing in the reservoir. For these methods the mineral buffers considered to be controlling H2S-H2 composition of fluids are as follows. The pyrite-magnetite buffer (FT-HSH1); the pyrite-hematite buffer (FT-HSH2) and the pyrite-pyrrhotite buffer (FT-HSH3). Currently from such models the estimations of both, temperature and steam fraction in the two-phase fluid are obtained graphically by using a blank diagram with a background theoretical solution as reference. Thus large errors are involved since the isotherms are highly nonlinear functions while reservoir steam fractions are taken from a logarithmic scale. In order to facilitate the use of the three FT-HSH methods and minimize visual interpolation errors, the EQUILGAS program that numerically solves the equations of the FT-HSH methods was developed. In this work the FT-HSH methods and the EQUILGAS program are described. Illustrative examples for Mexican fields are also given in order to help the users in deciding which method could be more suitable for every specific data set.

MULTI-ATTRIBUTE SEISMIC/ROCK PHYSICS APPROACH TO CHARACTERIZING FRACTURED RESERVOIRS

Energy Technology Data Exchange (ETDEWEB)

Gary Mavko

2000-10-01

This project consists of three key interrelated Phases, each focusing on the central issue of imaging and quantifying fractured reservoirs, through improved integration of the principles of rock physics, geology, and seismic wave propagation. This report summarizes the results of Phase I of the project. The key to successful development of low permeability reservoirs lies in reliably characterizing fractures. Fractures play a crucial role in controlling almost all of the fluid transport in tight reservoirs. Current seismic methods to characterize fractures depend on various anisotropic wave propagation signatures that can arise from aligned fractures. We are pursuing an integrated study that relates to high-resolution seismic images of natural fractures to the rock parameters that control the storage and mobility of fluids. Our goal is to go beyond the current state-of-the art to develop and demonstrate next generation methodologies for detecting and quantitatively characterizing fracture zones using seismic measurements. Our study incorporates 3 key elements: (1) Theoretical rock physics studies of the anisotropic viscoelastic signatures of fractured rocks, including up scaling analysis and rock-fluid interactions to define the factors relating fractures in the lab and in the field. (2) Modeling of optimal seismic attributes, including offset and azimuth dependence of travel time, amplitude, impedance and spectral signatures of anisotropic fractured rocks. We will quantify the information content of combinations of seismic attributes, and the impact of multi-attribute analyses in reducing uncertainty in fracture interpretations. (3) Integration and interpretation of seismic, well log, and laboratory data, incorporating field geologic fracture characterization and the theoretical results of items 1 and 2 above. The focal point for this project is the demonstration of these methodologies in the Marathon Oil Company Yates Field in West Texas.

Production performance laws of vertical wells by volume fracturing in CBM reservoirs

Directory of Open Access Journals (Sweden)

Liehui Zhang

2017-05-01

Full Text Available Volume fracturing technology has been widely applied in the development of coalbed methane (CBM reservoirs. As for the stimulated reservoir volume (SRV created by volume fracturing, the seepage laws of fluids are described more accurately and rationally in the rectangular composite model than in the traditional radial composite model. However, the rectangular composite model considering SRV cannot be solved using the analytical or semi-analytical function method, and its solution from the linear flow model has larger errors. In view of this, SRV areas of CBM reservoirs were described by means of dual-medium model in this paper. The complex CBM migration mechanisms were investigated comprehensively, including adsorption, desorption, diffusion and seepage. A well testing model for rectangular composite fracturing wells in CBM reservoirs based on unsteady-state diffusion was built and solved using the boundary element method combined with Laplace transformation, Stehfest numerical inversion and computer programming technology. Thus, production performance laws of CBM reservoirs were clarified. The flow regimes of typical well testing curves were divided and the effects on change laws of production performance from the boundary size of gas reservoirs, permeability of volume fractured areas, adsorption gas content, reservoir permeability and SRV size were analyzed. Eventually, CBM reservoirs after the volume fracturing stimulation were described more accurately and rationally. This study provides a theoretical basis for a better understanding of the CBM migration laws and an approach to evaluating and developing CBM reservoirs efficiently and rationally.

Closed-loop feedback control for microfluidic systems through automated capacitive fluid height sensing.

Science.gov (United States)

Soenksen, L R; Kassis, T; Noh, M; Griffith, L G; Trumper, D L

2018-03-13

Precise fluid height sensing in open-channel microfluidics has long been a desirable feature for a wide range of applications. However, performing accurate measurements of the fluid level in small-scale reservoirs (sensor contact needs to be avoided. In particular, gravity-driven systems used in several microfluidic applications to establish pressure gradients and impose flow remain open-loop and largely unmonitored due to these sensing limitations. Here we present an optimized self-shielded coplanar capacitive sensor design and automated control system to provide submillimeter fluid-height resolution (∼250 μm) and control of small-scale open reservoirs without the need for direct fluid contact. Results from testing and validation of our optimized sensor and system also suggest that accurate fluid height information can be used to robustly characterize, calibrate and dynamically control a range of microfluidic systems with complex pumping mechanisms, even in cell culture conditions. Capacitive sensing technology provides a scalable and cost-effective way to enable continuous monitoring and closed-loop feedback control of fluid volumes in small-scale gravity-dominated wells in a variety of microfluidic applications.

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).

Fracture Characterization in Enhanced Geothermal Systems by Wellbore and Reservoir Analysis

Energy Technology Data Exchange (ETDEWEB)

Horne, Roland N.; Li, Kewen; Alaskar, Mohammed; Ames, Morgan; Co, Carla; Juliusson, Egill; Magnusdottir, Lilja

2012-06-30

This report highlights the work that was done to characterize fractured geothermal reservoirs using production data. That includes methods that were developed to infer characteristic functions from production data and models that were designed to optimize reinjection scheduling into geothermal reservoirs, based on these characteristic functions. The characterization method provides a robust way of interpreting tracer and flow rate data from fractured reservoirs. The flow-rate data are used to infer the interwell connectivity, which describes how injected fluids are divided between producers in the reservoir. The tracer data are used to find the tracer kernel for each injector-producer connection. The tracer kernel describes the volume and dispersive properties of the interwell flow path. A combination of parametric and nonparametric regression methods were developed to estimate the tracer kernels for situations where data is collected at variable flow-rate or variable injected concentration conditions. The characteristic functions can be used to calibrate thermal transport models, which can in turn be used to predict the productivity of geothermal systems. This predictive model can be used to optimize injection scheduling in a geothermal reservoir, as is illustrated in this report.

A unique research partnership investigating the fundamental principles of subsurface carbon dioxide behaviour and carbonate reservoirs

Science.gov (United States)

Macdonald, I.; Blunt, M. J.; Maitland, G. C.

2017-12-01

Carbonate reservoirs hold the majority of CO2 sequestration potential, however, they are also more complicated than sandstone reservoirs in terms of heterogeneity and potential reactivity impact on operations. There are both significant carbonate reservoir CO2 sinks and CO2 point sources around Qatar making carbon capture and storage a potential decarbonisation pathway. The Qatar Carbonates and Carbon Storage Research Centre (QCCSRC) was formed in 2009 to address the gaps in our current knowledge of both local carbonate reservoir platforms and how CO2 would behave post sequestration. Our work spans 35 graduated PhD students, 10 still studying, 29 post-doctoral researchers, 18 faculty members all aided by 5 support staff and more than 100 MSc and summer students from 30 different countries, the centre has published over 150 papers in over 40 different journals. Our research is based within the Department of Chemical Engineering and the Department of Earth Science and Engineering. Our team annually attends over 20 conferences world-wide to disseminate our findings and activity engage in outreach events (UNFCCC, science festivals, social media, science bars, school visits, etc.). QCCSRC is a research framework agreement over 10 years and valued at $70 million between Qatar Petroleum, Shell, the Qatar Science and Technology Park and Imperial College London bringing together each organisation's unique capabilities. This novel quadruple helix management structure is responsible for the largest single industrially funded research programme conducted at Imperial College London. Our research has focused on data to create and/or improve predictive models for CO2 storage in carbonate reservoirs. Our three broad thematic areas include: Rocks : Rock-fluid interactions : Fluid-fluid interactions and are supported by 5 laboratories. Overall this unique programme is an example of how to approach grand challenges in the energy-carbon dilemma through long-term and multidisciplinary

Analysis of induced seismicity in geothermal reservoirs – An overview

Science.gov (United States)

Zang, Arno; Oye, Volker; Jousset, Philippe; Deichmann, Nicholas; Gritto, Roland; McGarr, Arthur F.; Majer, Ernest; Bruhn, David

2014-01-01

In this overview we report results of analysing induced seismicity in geothermal reservoirs in various tectonic settings within the framework of the European Geothermal Engineering Integrating Mitigation of Induced Seismicity in Reservoirs (GEISER) project. In the reconnaissance phase of a field, the subsurface fault mapping, in situ stress and the seismic network are of primary interest in order to help assess the geothermal resource. The hypocentres of the observed seismic events (seismic cloud) are dependent on the design of the installed network, the used velocity model and the applied location technique. During the stimulation phase, the attention is turned to reservoir hydraulics (e.g., fluid pressure, injection volume) and its relation to larger magnitude seismic events, their source characteristics and occurrence in space and time. A change in isotropic components of the full waveform moment tensor is observed for events close to the injection well (tensile character) as compared to events further away from the injection well (shear character). Tensile events coincide with high Gutenberg-Richter b-values and low Brune stress drop values. The stress regime in the reservoir controls the direction of the fracture growth at depth, as indicated by the extent of the seismic cloud detected. Stress magnitudes are important in multiple stimulation of wells, where little or no seismicity is observed until the previous maximum stress level is exceeded (Kaiser Effect). Prior to drilling, obtaining a 3D P-wave (Vp) and S-wave velocity (Vs) model down to reservoir depth is recommended. In the stimulation phase, we recommend to monitor and to locate seismicity with high precision (decametre) in real-time and to perform local 4D tomography for velocity ratio (Vp/Vs). During exploitation, one should use observed and model induced seismicity to forward estimate seismic hazard so that field operators are in a position to adjust well hydraulics (rate and volume of the

Coupled Hydro-Mechanical Simulations of CO2 Storage Supported by Pressure Management Demonstrate Synergy Benefits from Simultaneous Formation Fluid Extraction

Directory of Open Access Journals (Sweden)

Kempka Thomas

2015-04-01

Full Text Available We assessed the synergetic benefits of simultaneous formation fluid extraction during CO2 injection for reservoir pressure management by coupled hydro-mechanical simulations at the prospective Vedsted storage site located in northern Denmark. Effectiveness of reservoir pressure management was investigated by simulation of CO2 storage without any fluid extraction as well as with 66% and 100% equivalent volume formation fluid extraction from four wells positioned for geothermal heat recovery. Simulation results demonstrate that a total pressure reduction of up to about 1.1 MPa can be achieved at the injection well. Furthermore, the areal pressure perturbation in the storage reservoir can be significantly decreased compared to the simulation scenario without any formation fluid extraction. Following a stress regime analysis, two stress regimes were considered in the coupled hydro-mechanical simulations indicating that the maximum ground surface uplift is about 0.24 m in the absence of any reservoir pressure management. However, a ground uplift mitigation of up to 37.3% (from 0.24 m to 0.15 m can be achieved at the injection well by 100% equivalent volume formation fluid extraction. Well-based adaptation of fluid extraction rates can support achieving zero displacements at the proposed formation fluid extraction wells located close to urban infrastructure. Since shear and tensile failure do not occur under both stress regimes for all investigated scenarios, it is concluded that a safe operation of CO2 injection with simultaneous formation fluid extraction for geothermal heat recovery can be implemented at the Vedsted site.

Hydrochemical Characteristics and Evolution of Geothermal Fluids in the Chabu High-Temperature Geothermal System, Southern Tibet

Directory of Open Access Journals (Sweden)

X. Wang

2018-01-01

Full Text Available This study defines reasonable reservoir temperatures and cooling processes of subsurface geothermal fluids in the Chabu high-temperature geothermal system. This system lies in the south-central part of the Shenzha-Xietongmen hydrothermal active belt and develops an extensive sinter platform with various and intense hydrothermal manifestations. All the geothermal spring samples collected systematically from the sinter platform are divided into three groups by cluster analysis of major elements. Samples of group 1 and group 3 are distributed in the central part and northern periphery of the sinter platform, respectively, while samples of group 2 are scattered in the transitional zone between groups 1 and 3. The hydrochemical characteristics show that the geothermal waters of the research area have generally mixed with shallow cooler waters in reservoirs. The reasonable reservoir temperatures and the mixing processes of the subsurface geothermal fluids could be speculated by combining the hydrochemical characteristics of geothermal springs, calculated results of the chemical geothermometers, and silica-enthalpy mixing models. Contour maps are applied to measured emerging temperatures, mass flow rates, total dissolved solids of spring samples, and reasonable subsurface temperatures. They indicate that the major cooling processes of the subsurface geothermal fluids gradually transform from adiabatic boiling to conduction from the central part to the peripheral belt. The geothermal reservoir temperatures also show an increasing trend. The point with the highest reservoir temperature (256°C appears in the east-central part of the research area, which might be the main up-flow zone. The cooling processes of the subsurface geothermal fluids in the research area can be shown on an enthalpy-chloride plot. The deep parent fluid for the Chabu geothermal field has a Cl− concentration of 290 mg/L and an enthalpy of 1550 J/g (with a water temperature of

Mineralogical controls on porosity and water chemistry during O_2-SO_2-CO_2 reaction of CO_2 storage reservoir and cap-rock core

International Nuclear Information System (INIS)

Pearce, Julie K.; Golab, Alexandra; Dawson, Grant K.W.; Knuefing, Lydia; Goodwin, Carley; Golding, Suzanne D.

2016-01-01

Reservoir and cap-rock core samples with variable lithology's representative of siliciclastic reservoirs used for CO_2 storage have been characterized and reacted at reservoir conditions with an impure CO_2 stream and low salinity brine. Cores from a target CO_2 storage site in Queensland, Australia were tested. Mineralogical controls on the resulting changes to porosity and water chemistry have been identified. The tested siliciclastic reservoir core samples can be grouped generally into three responses to impure CO_2-brine reaction, dependent on mineralogy. The mineralogically clean quartzose reservoir cores had high porosities, with negligible change after reaction, in resolvable porosity or mineralogy, calculated using X-ray micro computed tomography and QEMSCAN. However, strong brine acidification and a high concentration of dissolved sulphate were generated in experiments owing to minimal mineral buffering. Also, the movement of kaolin has the potential to block pore throats and reduce permeability. The reaction of the impure CO_2-brine with calcite-cemented cap-rock core samples caused the largest porosity changes after reaction through calcite dissolution; to the extent that one sample developed a connection of open pores that extended into the core sub-plug. This has the potential to both favor injectivity but also affect CO_2 migration. The dissolution of calcite caused the buffering of acidity resulting in no significant observable silicate dissolution. Clay-rich cap-rock core samples with minor amounts of carbonate minerals had only small changes after reaction. Created porosity appeared mainly disconnected. Changes were instead associated with decreases in density from Fe-leaching of chlorite or dissolution of minor amounts of carbonates and plagioclase. The interbedded sandstone and shale core also developed increased porosity parallel to bedding through dissolution of carbonates and reactive silicates in the sandy layers. Tight interbedded cap

Characterization of Fractured Reservoirs Using a Combination of Downhole Pressure and Self-Potential Transient Data

OpenAIRE

Yuji Nishi; Tsuneo Ishido

2012-01-01

In order to appraise the utility of self-potential (SP) measurements to characterize fractured reservoirs, we carried out continuous SP monitoring using multi Ag-AgCl electrodes installed within two open holes at the Kamaishi Mine, Japan. The observed ratio of SP change to pressure change associated with fluid flow showed different behaviors between intact host rock and fractured rock regions. Characteristic behavior peculiar to fractured reservoirs, which is predicted from numerical simulati...

Waste-aware fluid volume assignment for flow-based microfluidic biochips

DEFF Research Database (Denmark)

Schneider, Alexander Rüdiger; Pop, Paul; Madsen, Jan

2017-01-01

complex Fluidic Units (FUs) such as switches, micropumps, mixers and separators can be constructed. When running a biochemical application on a FBMB, fluid volumes are dispensed from input reservoirs and used by the FUs. Given a biochemical application and a biochip, we are interested in determining...... the fluid volume assignment for each operation of the application, such that the FUs volume requirements are satisfied, while over- and underflow are avoided and the total volume of fluid used is minimized. We propose an algorithm for this fluid assignment problem. Compared to previous work, our method...

Movement of Sediment Associated With Lowered Reservoir Levels in the Rio La Venta Arm of the Presa Netzahualcoyotl, Chiapas, Mexico

Science.gov (United States)

Hilton, S.; de La Fuente, J.; Lisle, T. E.; Velasquez, J.; Allison, B.; Olson, B.; Quinones, R.

2003-12-01

A joint sedimentation study is currently underway at the Netzahualcoyotl reservoir in Chiapas, Mexico, involving the Comision Nacional de Areas Naturales Protegidas (CONANP) of the Secretaria de Medio Ambiente y Recursos Naturales and the USDA Forest Service. The reservoir is adjacent to the Reserva de la Biosfera, Selva El Ocote, administered by CONANP. Ongoing research is intended to provide watershed and reservoir managers with strategies to protect the resources of Rio La Venta canyon. The Rio La Venta arm of the reservoir is incised into karst terrain, with near-vertical limestone walls up to 300 meters high. The canyon is fed by two rivers, Rio La Selva and Rio Negro, and is surrounded by pristine tropical forest. The majority of the clastic sediment (predominantly sand and fine gravel) entering the reservoir originates in the headwaters of the two rivers which are underlain by weathered and dissected granitic terrain. Rapid sedimentation of the partially inundated canyon poses a threat to the aquatic ecosystem, as well as to recreational resources. Longitudinal and transverse profiles were surveyed in the inundated canyon in March of 2002 and repeated in April of 2003 when the reservoir level was 15 meters lower. The 2002 longitudinal profile shows an inflection from a slope of 0.0017 to one of 0.0075 at 7.2 km downstream of the mouth of Rio Negro. In 2003, the two slopes remained the same, but the bed lowered about 5 meters and the inflection point moved downstream about 2.3 km. We calculated that reservoir lowering in 2003 allowed the transport of 2.5 million cubic meters of sand further out into the reservoir. This volume is more than the average annual rate of filling up to the 2002 level since 1984 when sedimentation was not as advanced (De la Fuente et al., 2002), which was calculated disregarding loss of sediment to the main reservoir. Field observations at late dry season low flows in 2003 revealed active transport of sand and pebbles and formation

3-D RESERVOIR AND STOCHASTIC FRACTURE NETWORK MODELING FOR ENHANCED OIL RECOVERY, CIRCLE RIDGE PHOSPHORIA/TENSLEEP RESERVOIR, WIND RIVER RESERVATION, ARAPAHO AND SHOSHONE TRIBES, WYOMING

Energy Technology Data Exchange (ETDEWEB)

Paul La Pointe; Jan Hermanson; Robert Parney; Thorsten Eiben; Mike Dunleavy; Ken Steele; John Whitney; Darrell Eubanks; Roger Straub

2002-11-18

This report describes the results made in fulfillment of contract DE-FG26-00BC15190, ''3-D Reservoir and Stochastic Fracture Network Modeling for Enhanced Oil Recovery, Circle Ridge Phosphoria/Tensleep Reservoir, Wind River Reservation, Arapaho and Shoshone Tribes, Wyoming''. The goal of this project is to improve the recovery of oil from the Tensleep and Phosphoria Formations in Circle Ridge Oilfield, located on the Wind River Reservation in Wyoming, through an innovative integration of matrix characterization, structural reconstruction, and the characterization of the fracturing in the reservoir through the use of discrete fracture network models. Fields in which natural fractures dominate reservoir permeability, such as the Circle Ridge Field, often experience sub-optimal recovery when recovery processes are designed and implemented that do not take advantage of the fracture systems. For example, a conventional waterflood in a main structural block of the Field was implemented and later suspended due to unattractive results. It is estimated that somewhere less than 20% of the OOIP in the Circle Ridge Field have been recovered after more than 50 years' production. Marathon Oil Company identified the Circle Ridge Field as an attractive candidate for several advanced IOR processes that explicitly take advantage of the natural fracture system. These processes require knowledge of the distribution of matrix porosity, permeability and oil saturations; and understanding of where fracturing is likely to be well-developed or poorly developed; how the fracturing may compartmentalize the reservoir; and how smaller, relatively untested subthrust fault blocks may be connected to the main overthrust block. For this reason, the project focused on improving knowledge of the matrix properties, the fault block architecture and to develop a model that could be used to predict fracture intensity, orientation and fluid flow/connectivity properties. Knowledge

A novel viscoelastic surfactant suitable for use in high temperature carbonate reservoirs for diverted acidizing stimulation treatments

Energy Technology Data Exchange (ETDEWEB)

Holt, Stuart; Zhou, Jian; Gadberry, Fred [AkzoNobel Surface Chemistry, Forth Worth, TX (United States); Nasr-El-Din, Hisham; Wang, Guanqun [Texas A and M University, College Station, TX (United States). Dept. of Petroleum Engineering

2012-07-01

Due to the low permeability of many carbonate hydrocarbon-bearing reservoirs, it is difficult to achieve economic hydrocarbon recovery from a well without secondary stimulation. Bullheading of strong acids, such as HCl is practiced in low temperature reservoirs, but as the bottom hole temperature (BHT) rises, the acid becomes increasingly corrosive, causing facial dissolution and sub-optimal wormhole network development. In the last decade, viscoelastic surfactants (VES) have been added to HCl acid systems to improve the stimulation of HT carbonate reservoirs. The VES form 'living polymers' or worm-like micelles as electrolyte concentration rises in the acid due to reaction with the reservoir. This leads to viscosification of the stimulation fluid. The viscosification slows further acid reaction in the region already contacted by the acid, and forces the acid to take an alternate path into the rock, leading to diversion of the acids further down the well to the harder to access toe or lower permeability zones. Until recently, the maximum BHT that such VES-based diverting systems could be used was up to about 250 deg F/120 deg C. Above that temperature, all viscous properties of the fluid are lost, destroying the mechanism of acid diversion. A recently developed novel viscoelastic surfactant provides nearly 100 deg F/55 deg C extension in the BHT range in which diverted acid treatments can be used. These fluids are able to maintain both viscosity up to about 375 deg F/190 deg C, with the elastic modulus predominating up to 350 deg F/175 deg C. It is the elasticity which is particularly important in acid diversion. These fluids can have their viscosity readily broken by in-situ hydrocarbons, dilution with water or by using a mutual solvent. The broken fluids are readily removed from the near-well bore, leaving the newly created wormhole network to produce the target hydrocarbons. The new VES is significantly more environmentally benign compared with current

Arm (Advanced Reservoir Management Vs. Eor Gestion avancée de réservoir contre récupération assistée des hydrocarbures (RAH

Directory of Open Access Journals (Sweden)

Chierici G. L.

2006-11-01

Full Text Available Advanced Reservoir Management (ARM techniques aimed at a better reservoir coverage by injected fluid(s through the improvement of interwell connectivity and recourse to gravity drainage are shown to have a better chance than EOR techniques in improving oil recovery with satisfactory economic results. Les techniques de gestion avancée de réservoir (ARM, Advanced Reservoir Management visant une meilleure couverture du réservoir par les fluides injectés grâce à l'amélioration des interconnexions entre les puits et au recours au drainage par gravité semblent offrir plus de possibilités que les techniques de RAH, pour améliorer la récupération du pétrole dans de bonnes conditions économiques.

INTEGRATED GEOLOGIC-ENGINEERING MODEL FOR REEF AND CARBONATE SHOAL RESERVOIRS ASSOCIATED WITH PALEOHIGHS: UPPER JURASSIC SMACKOVER FORMATION, NORTHEASTERN GULF OF MEXICO

Energy Technology Data Exchange (ETDEWEB)

Ernest A. Mancini

2002-09-25

The University of Alabama in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company are undertaking an integrated, interdisciplinary geoscientific and engineering research project. The project is designed to characterize and model reservoir architecture, pore systems and rock-fluid interactions at the pore to field scale in Upper Jurassic Smackover reef and carbonate shoal reservoirs associated with varying degrees of relief on pre-Mesozoic basement paleohighs in the northeastern Gulf of Mexico. The project effort includes the prediction of fluid flow in carbonate reservoirs through reservoir simulation modeling which utilizes geologic reservoir characterization and modeling and the prediction of carbonate reservoir architecture, heterogeneity and quality through seismic imaging. The primary objective of the project is to increase the profitability, producibility and efficiency of recovery of oil from existing and undiscovered Upper Jurassic fields characterized by reef and carbonate shoals associated with pre-Mesozoic basement paleohighs. The principal research effort for Year 2 of the project has been reservoir characterization, 3-D modeling and technology transfer. This effort has included six tasks: (1) the study of rockfluid interactions, (2) petrophysical and engineering characterization, (3) data integration, (4) 3-D geologic modeling, (5) 3-D reservoir simulation and (6) technology transfer. This work was scheduled for completion in Year 2. Overall, the project work is on schedule. Geoscientific reservoir characterization is essentially completed. The architecture, porosity types and heterogeneity of the reef and shoal reservoirs at Appleton and Vocation Fields have been characterized using geological and geophysical data. The study of rock-fluid interactions is near completion. Observations regarding the diagenetic processes influencing pore system development and

Modeling Studies to Constrain Fluid and Gas Migration Associated with Hydraulic Fracturing Operations

Science.gov (United States)

Rajaram, H.; Birdsell, D.; Lackey, G.; Karra, S.; Viswanathan, H. S.; Dempsey, D.

2015-12-01

The dramatic increase in the extraction of unconventional oil and gas resources using horizontal wells and hydraulic fracturing (fracking) technologies has raised concerns about potential environmental impacts. Large volumes of hydraulic fracturing fluids are injected during fracking. Incidents of stray gas occurrence in shallow aquifers overlying shale gas reservoirs have been reported; whether these are in any way related to fracking continues to be debated. Computational models serve as useful tools for evaluating potential environmental impacts. We present modeling studies of hydraulic fracturing fluid and gas migration during the various stages of well operation, production, and subsequent plugging. The fluid migration models account for overpressure in the gas reservoir, density contrast between injected fluids and brine, imbibition into partially saturated shale, and well operations. Our results highlight the importance of representing the different stages of well operation consistently. Most importantly, well suction and imbibition both play a significant role in limiting upward migration of injected fluids, even in the presence of permeable connecting pathways. In an overall assessment, our fluid migration simulations suggest very low risk to groundwater aquifers when the vertical separation from a shale gas reservoir is of the order of 1000' or more. Multi-phase models of gas migration were developed to couple flow and transport in compromised wellbores and subsurface formations. These models are useful for evaluating both short-term and long-term scenarios of stray methane release. We present simulation results to evaluate mechanisms controlling stray gas migration, and explore relationships between bradenhead pressures and the likelihood of methane release and transport.

Origin of late pleistocene formation water in Mexican oil reservoirs

Energy Technology Data Exchange (ETDEWEB)

Birkle, P. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

2004-07-01

Brine water invasion into petroleum reservoirs, especially in sedimentary basins, are known from a variety of global oil field, such as the Western Canada sedimentary basin and, the central Mississippi Salt Dome basin (Kharaka et al., 1987). The majority of oil wells, especially in the more mature North American fields, produce more water than they do oil (Peachey et al., 1998). In the case of Mexican oil fields, increasing volumes of invading water into the petroleum wells were detected during the past few years. Major oil reserves in the SE-part of the Gulf of Mexico are economically affected due to decreases in production rate, pipeline corrosion and well closure. The origin of deep formation water in many sedimentary basins is still controversial: Former hypothesis mainly in the 60's, explained the formation of formation water by entrapment of seawater during sediment deposition. Subsequent water-rock interaction processes explain the chemical evolution of hydrostatic connate water. More recent hydrodynamic models, mainly based on isotopic data, suggest the partial migration of connate fluids, whereas the subsequent invasion of surface water causes mixing processes (Carpenter 1978). As part of the presented study, a total of 90 oil production wells were sampled from 1998 to 2004 to obtain chemical (Major and trace elements) and isotopic composition ({sup 2}H, {sup 13}C, {sup 14}C, {sup 18}O {sup 36}Cl, {sup 37}Cl, {sup 87}Sr, {sup 129}I, tritium) of deep formation water at the Mexican Gulf coast. Samples were extracted from carbonate-type reservoirs of the oil fields Luna, Samaria-Sitio Grande, Jujo-Tecominoac (on-shore), and Pol-Chuc (off-shore, including Abkatun, Batab, Caan, and Taratunich) at a depth between 2,900 m b.s.l. and 6,100 m b.s.l. During the field work, the influence of atmospheric contamination e.g. by CO{sub 2}-atmospheric input was avoided by using an interval sampler to get in-situ samples from the extraction zone of selected bore holes

Improved Efficiency of Miscible CO2 Floods and Enhanced Prospects for CO2 Flooding Heterogeneous Reservoirs; ANNUAL

International Nuclear Information System (INIS)

Grigg, Reid B.; Schechter, David S.

1999-01-01

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)

1D Thermal-Hydraulic-Chemical (THC) Reactive transport modeling for deep geothermal systems: A case study of Groß Schönebeck reservoir, Germany

Science.gov (United States)

Driba, D. L.; De Lucia, M.; Peiffer, S.

2014-12-01

Fluid-rock interactions in geothermal reservoirs are driven by the state of disequilibrium that persists among solid and solutes due to changing temperature and pressure. During operation of enhanced geothermal systems, injection of cooled water back into the reservoir disturbs the initial thermodynamic equilibrium between the reservoir and its geothermal fluid, which may induce modifications in permeability through changes in porosity and pore space geometry, consequently bringing about several impairments to the overall system.Modeling of fluid-rock interactions induced by injection of cold brine into Groß Schönebeck geothermal reservoir system situated in the Rotliegend sandstone at 4200m depth have been done by coupling geochemical modeling Code Phreeqc with OpenGeoSys. Through batch modeling the re-evaluation of the measured hydrochemical composition of the brine has been done using Quintessa databases, the results from the calculation indicate that a mineral phases comprising of K-feldspar, hematite, Barite, Calcite and Dolomite was found to match the hypothesis of equilibrium with the formation fluid, Reducing conditions are presumed in the model (pe = -3.5) in order to match the amount of observed dissolved Fe and thus considered as initial state for the reactive transport modeling. based on a measured composition of formation fluids and the predominant mineralogical assemblage of the host rock, a preliminary 1D Reactive transport modeling (RTM) was run with total time set to 30 years; results obtained for the initial simulation revealed that during this period, no significant change is evident for K-feldspar. Furthermore, the precipitation of calcite along the flow path in the brine results in a drop of pH from 6.2 to a value of 5.2 noticed over the simulated period. The circulation of cooled fluid in the reservoir is predicted to affect the temperature of the reservoir within the first 100 -150m from the injection well. Examination of porosity change in

Flask fluid flow simulation using CFD

International Nuclear Information System (INIS)

Swindlehurst, W.E.; Livesey, E.; Worthington, D.

1989-01-01

BNFL and its subsidiary Company, PNTL, design and operate waterfilled LWR fuel transport flasks for the international transport of irradiated fuel. Although some 150 flasks are currently in operation, new flask designs are being developed. As part of the supporting R and D program, Computational Fluid Dynamics (CFD) codes are being investigated as a means of predicting fluid movements and temperatures within the complex internal geometry of flasks. The ability to simulate fluid flow is particularly important when convection heat transfer is significant. Although obviously relevant to water filled flasks, the technique is applicable to dry flask thermal assessments (where experience shows that convection heat transfer is often underestimated). Computational Fluid Dynamics has emerged in recent years as an important technique in engineering design and safety assessments. Cheaper computing and the development of general CFD codes allows complex engineering structures to be analyzed. However, because of this complexity, it is essential that the application and associated modeling assumptions are critically reviewed. To assess the ability of a CFD code to model flask internals, the code PHOENICS has been used to model the fluid movements in a BNFL Excellox-type flask and the results compared with test data

Numerical Simulation of Natural Gas Flow in Anisotropic Shale Reservoirs

KAUST Repository

Negara, Ardiansyah

2015-11-09

Shale gas resources have received great attention in the last decade due to the decline of the conventional gas resources. Unlike conventional gas reservoirs, the gas flow in shale formations involves complex processes with many mechanisms such as Knudsen diffusion, slip flow (Klinkenberg effect), gas adsorption and desorption, strong rock-fluid interaction, etc. Shale formations are characterized by the tiny porosity and extremely low-permeability such that the Darcy equation may no longer be valid. Therefore, the Darcy equation needs to be revised through the permeability factor by introducing the apparent permeability. With respect to the rock formations, several studies have shown the existence of anisotropy in shale reservoirs, which is an essential feature that has been established as a consequence of the different geological processes over long period of time. Anisotropy of hydraulic properties of subsurface rock formations plays a significant role in dictating the direction of fluid flow. The direction of fluid flow is not only dependent on the direction of pressure gradient, but it also depends on the principal directions of anisotropy. Therefore, it is very important to take into consideration anisotropy when modeling gas flow in shale reservoirs. In this work, the gas flow mechanisms as mentioned earlier together with anisotropy are incorporated into the dual-porosity dual-permeability model through the full-tensor apparent permeability. We employ the multipoint flux approximation (MPFA) method to handle the full-tensor apparent permeability. We combine MPFA method with the experimenting pressure field approach, i.e., a newly developed technique that enables us to solve the global problem by breaking it into a multitude of local problems. This approach generates a set of predefined pressure fields in the solution domain in such a way that the undetermined coefficients are calculated from these pressure fields. In other words, the matrix of coefficients

Numerical Simulation of Natural Gas Flow in Anisotropic Shale Reservoirs

KAUST Repository

Negara, Ardiansyah; Salama, Amgad; Sun, Shuyu; Elgassier, Mokhtar; Wu, Yu-Shu

2015-01-01

Shale gas resources have received great attention in the last decade due to the decline of the conventional gas resources. Unlike conventional gas reservoirs, the gas flow in shale formations involves complex processes with many mechanisms such as Knudsen diffusion, slip flow (Klinkenberg effect), gas adsorption and desorption, strong rock-fluid interaction, etc. Shale formations are characterized by the tiny porosity and extremely low-permeability such that the Darcy equation may no longer be valid. Therefore, the Darcy equation needs to be revised through the permeability factor by introducing the apparent permeability. With respect to the rock formations, several studies have shown the existence of anisotropy in shale reservoirs, which is an essential feature that has been established as a consequence of the different geological processes over long period of time. Anisotropy of hydraulic properties of subsurface rock formations plays a significant role in dictating the direction of fluid flow. The direction of fluid flow is not only dependent on the direction of pressure gradient, but it also depends on the principal directions of anisotropy. Therefore, it is very important to take into consideration anisotropy when modeling gas flow in shale reservoirs. In this work, the gas flow mechanisms as mentioned earlier together with anisotropy are incorporated into the dual-porosity dual-permeability model through the full-tensor apparent permeability. We employ the multipoint flux approximation (MPFA) method to handle the full-tensor apparent permeability. We combine MPFA method with the experimenting pressure field approach, i.e., a newly developed technique that enables us to solve the global problem by breaking it into a multitude of local problems. This approach generates a set of predefined pressure fields in the solution domain in such a way that the undetermined coefficients are calculated from these pressure fields. In other words, the matrix of coefficients

Seismic evaluation of a cooling water reservoir facility including fluid-structure and soil-structure interaction effects

International Nuclear Information System (INIS)

Kabir, A.F.; Maryak, M.E.

1991-01-01

Seismic analyses and structural evaluations were performed for a cooling water reservoir of a nuclear reactor facility. The horizontal input seismic motion was the NRC Reg. guide 1.60 spectrum shape anchored at 0.20g zero period acceleration. Vertical input was taken as two-thirds of the horizontal input. Soil structure interaction and hydrodynamic effects were addressed in the seismic analyses. Uncertainties in the soil properties were accounted for by considering three soil profiles. Two 2-dimensional SSI models and a 3-dimensional static model. Representing different areas of the reservoir structures were developed and analyzed to obtain seismic forces and moments, and accelerations at various locations. The results included in this paper indicated that both hydrodynamic and soil-structure interaction effects are significant contributors to the seismic responses of the water-retaining walls of the reservoir

Micro- and macro-scale petrophysical characterization of potential reservoir units from the Northern Israel

Science.gov (United States)

Haruzi, Peleg; Halisch, Matthias; Katsman, Regina; Waldmann, Nicolas

2016-04-01

Lower Cretaceous sandstone serves as hydrocarbon reservoir in some places over the world, and potentially in Hatira formation in the Golan Heights, northern Israel. The purpose of the current research is to characterize the petrophysical properties of these sandstone units. The study is carried out by two alternative methods: using conventional macroscopic lab measurements, and using CT-scanning, image processing and subsequent fluid mechanics simulations at a microscale, followed by upscaling to the conventional macroscopic rock parameters (porosity and permeability). Comparison between the upscaled and measured in the lab properties will be conducted. The best way to upscale the microscopic rock characteristics will be analyzed based the models suggested in the literature. Proper characterization of the potential reservoir will provide necessary analytical parameters for the future experimenting and modeling of the macroscopic fluid flow behavior in the Lower Cretaceous sandstone.

Anomalous fluid emission of a deep borehole in a seismically active area of Northern Apennines (Italy)

International Nuclear Information System (INIS)

Heinicke, J.; Italiano, F.; Koch, U.; Martinelli, G.; Telesca, L.

2010-01-01

The Miano borehole, 1047 m deep, is located close to the river Parma in the Northern Apennines, Italy. A measuring station has been installed to observe the discharge of fluids continuously since November 2004. The upwelling fluid of this artesian well is a mixture of thermal water and CH 4 as main components. In non-seismogenic areas, a relatively constant fluid emission would be expected, perhaps overlaid with long term variations from that kind of deep reservoir over time. However, the continuous record of the fluid emission, in particular the water discharge, the gas flow rate and the water temperature, show periods of stable values interrupted by anomalous periods of fluctuations in the recorded parameters. The anomalous variations of these parameters are of low amplitude in comparison to the total values but significant in their long-term trend. Meteorological effects due to rain and barometric pressure were not detected in recorded data probably due to reservoir depth and relatively high reservoir overpressure. Influences due to the ambient temperature after the discharge were evaluated by statistical analysis. Our results suggest that recorded changes in fluid emission parameters can be interpreted as a mixing process of different fluid components at depth by variations in pore pressure as a result of seismogenic stress variation. Local seismicity was analyzed in comparison to the fluid physico-chemical data. The analysis supports the idea that an influence on fluid transport conditions due to geodynamic processes exists. Water temperature data show frequent anomalies probably connected with possible precursory phenomena of local seismic events.

A numerical study of EGS heat extraction process based on a thermal non-equilibrium model for heat transfer in subsurface porous heat reservoir

Science.gov (United States)

Chen, Jiliang; Jiang, Fangming

2016-02-01

With a previously developed numerical model, we perform a detailed study of the heat extraction process in enhanced or engineered geothermal system (EGS). This model takes the EGS subsurface heat reservoir as an equivalent porous medium while it considers local thermal non-equilibrium between the rock matrix and the fluid flowing in the fractured rock mass. The application of local thermal non-equilibrium model highlights the temperature-difference heat exchange process occurring in EGS reservoirs, enabling a better understanding of the involved heat extraction process. The simulation results unravel the mechanism of preferential flow or short-circuit flow forming in homogeneously fractured reservoirs of different permeability values. EGS performance, e.g. production temperature and lifetime, is found to be tightly related to the flow pattern in the reservoir. Thermal compensation from rocks surrounding the reservoir contributes little heat to the heat transmission fluid if the operation time of an EGS is shorter than 15 years. We find as well the local thermal equilibrium model generally overestimates EGS performance and for an EGS with better heat exchange conditions in the heat reservoir, the heat extraction process acts more like the local thermal equilibrium process.

4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir

Energy Technology Data Exchange (ETDEWEB)

Richard D. Miller; Abdelmoneam E. Raef; Alan P. Byrnes; William E. Harrison

2007-06-30

The objective of this research project was to acquire, process, and interpret multiple high-resolution 3-D compressional wave and 2-D, 2-C shear wave seismic data in the hopes of observing changes in fluid characteristics in an oil field before, during, and after the miscible carbon dioxide (CO{sub 2}) flood that began around December 1, 2003, as part of the DOE-sponsored Class Revisit Project (DOE No.DE-AC26-00BC15124). Unique and key to this imaging activity is the high-resolution nature of the seismic data, minimal deployment design, and the temporal sampling throughout the flood. The 900-m-deep test reservoir is located in central Kansas oomoldic limestones of the Lansing-Kansas City Group, deposited on a shallow marine shelf in Pennsylvanian time. After 30 months of seismic monitoring, one baseline and eight monitor surveys clearly detected changes that appear consistent with movement of CO{sub 2} as modeled with fluid simulators and observed in production data. Attribute analysis was a very useful tool in enhancing changes in seismic character present, but difficult to interpret on time amplitude slices. Lessons learned from and tools/techniques developed during this project will allow high-resolution seismic imaging to be routinely applied to many CO{sub 2} injection programs in a large percentage of shallow carbonate oil fields in the midcontinent.

Model of erosion–landslide interaction in the context of the reservoir ...

Indian Academy of Sciences (India)

the reservoir water level variations (East Siberia, Russia):. Factors ... The landslide and fluid soil creep cause the change in the gully head form and .... with yearly level fluctuations in the range of 2–3 m and lowering .... (boiling of triturated specimen with sodium pyrophosphate ... E; altitude: 427 m a.s.l., Russian. Federation) ...

Geological storage of carbon dioxide in the coal seams: from material to the reservoir

International Nuclear Information System (INIS)

Nikoosokhan, S.

2012-01-01

CO 2 emissions into the atmosphere are recognized to have a significant effect on global warming. Geological storage of CO 2 is widely regarded as an essential approach to reduce the impact of such emissions on the environment. Moreover, injecting carbon dioxide in coal bed methane reservoirs facilitates the recovery of the methane naturally present, a process known as enhanced coal bed methane recovery (ECBM). But the swelling of the coal matrix induced by the preferential adsorption by coal of carbon dioxide over the methane in place leads to a closure of the cleat system (a set of small natural fractures) of the reservoir and therefore to a loss of injectivity. This PhD thesis is dedicated to a study of how this injectivity evolves in presence of fluids. We derive two poro-mechanical dual-porosity models for a coal bed reservoir saturated by a pure fluid. The resulting constitutive equations enable to better understand and model the link between the injectivity of a coal seam and the adsorption-induced swelling of coal. For both models, the pore space of the reservoir is considered to be divided into the macroporous cleats and the pores of the coal matrix. The two models differ by how adsorption of fluid is taken into account: the first model is restricted to surface adsorption, while the second model can be applied for adsorption in a medium with a generic pore size distribution and thus in a microporous medium such as coal, in which adsorption mostly occurs by micropore filling. The latter model is calibrated on two coals with different sorption and swelling properties. We then perform simulations at various scales (Representative Elementary Volume, coal sample, coal seam). In particular, we validate our model on experimental data of adsorption-induced variations of permeability of coal. We also perform simulations of seams from which methane would be produced (CBM) or of methane-free seams into which CO 2 would be injected. We study the effect of various

Lagrange formalism for a system of several fluids interacting electromagnetically

International Nuclear Information System (INIS)

Vuillemin, M.

1964-01-01

After giving the Lagrange expression for a conducting fluid in an external electromagnetic field, the author shows that a Lagrange expression exists for describing the evolution of a system of interacting fluids obtained by adding the Lagrange expression of each fluid.to that of the electromagnetic field. By variation are obtained the fluid movement equation coupled to the Maxwell equations. It is shown that the study of small movements around a stationary state can be deduced from the Lagrange equation expanded to the second power order of the perturbation. It is then possible to deduce the normal mode equations and the study the stability by examining the modes which are marginally stable. (author) [fr

Thermal analysis of reservoir structure versus capillary pumped loop

International Nuclear Information System (INIS)

Lin Hungwen; Lin Weikeng

2009-01-01

Capillary pumped loop (CPL) was already used in man-made satellites and space aircrafts with proven heat control technology. However, small-sized CPL had not yet made a breakthrough application in electronic components owing to poor heat-absorption capacity of evaporator structure. Hence, a small-scale CPL was designed for server in this research. The evaporator was designed with a circular groove and embedded with a high density polyethylene (HDPE) as a capillary structure to absorb working fluid. The influence of reservoir upon thermal resistance was also analyzed. The experimental results showed that, under a filling level of 72%, CPL with optimized design could remove 110 W energy while maintaining its temperature at 80 deg. C. Comparison of CPL with/without reservoir, the loop thermal resistance R th,loop was reduced by 0.14 deg. C/W and was able to increase the stability of CPL, too, the results confirmed that reservoir could enhance CPL performance and this technology will probably find application in electronics cooling for electronic devices

Three-component seismic data in thin interbedded reservoir exploration

Science.gov (United States)

Zhang, Li-Yan; Wang, Yan-Chun; Pei, Jiang-Yun

2015-03-01

We present the first successful application of three-component seismic data to thin interbedded reservoir characterization in the Daqing placanticline of the LMD oilfield. The oilfield has reached the final high water cut stage and the principal problem is how to recognize the boundaries of sand layers that are thicker than 2 m. Conventional interpretation of single PP-wave seismic data results in multiple solutions, whereas the introduction of PS-wave enhances the reliability of interpretation. We analyze the gas reservoir characteristics by joint PP- and PS-waves, and use the amplitude and frequency decomposition attributes to delineate the gas reservoir boundaries because of the minimal effect of fluids on S-wave. We perform joint inversion of PP- and PS-waves to obtain V P/ V S, λρ, and µ ρ and map the lithology changes by using density, λρ, and µ ρ. The 3D-3C attribute λρ slices describe the sand layers distribution, while considering the well log data, and point to favorable region for tapping the remaining oil.

Advances in complex reservoir evaluation based on geophysical well logs

Energy Technology Data Exchange (ETDEWEB)

Fertl, W.H.; Sinha, A.K. (Western Atlas International, Inc., Houston, TX (USA)); McDougall, J.G. (Western Atlas Canada Ltd., Calgary, AB (Canada))

1988-09-01

The matrix of reservoirs having complex lithologies, cause different density, neutron, and acoustic responses. Therefore the lithologies and effective porosity of reservoirs can be determined by using various crossplot techniques on data collected from two of these logs. The Complex Reservoir Analysis program (CRA) computes lithology, porosity, water saturation and relative permeabilities in formations with interbedded limestone, dolomite, and anhydrite. Porosity options include crossplot and individual log response techniques. Corrections for light hydrocarbons were applied. In solving for porosity and mineral volumes, sand, limestone, dolomite, and anhydrite lines were defined on either density/neutron or neutron/acoustic crossplots. Four additional mineral lines were specified. Incorporation of Pe data from the Z-Densilog provided a significant advance in evaluating complex reservoirs via the Z-CRA analysis. The classic reservoir evaluation program CLASS, was used to perform both minerals and shaly evaluation based on density, neutron, resistivity, and natural gamma ray spectral measurements. Computations included total and effective porosities, fluid saturation distribution based on the Wasman-Smits model, productivity indices, and volume and distribution of clay minerals. Additional computed formation parameters included log-derived cation exchange capacity and hydrogen index of dry clay matrix to determine the type and amount of smectite, illite and chlorite/kaolinite present. Canadian field experiences was used to illustrate and support the techniques described. 11 refs., 11 figs., 6 tabs.

Biotelemetry study of spring and summer habitat selection by striped bass in Cherokee Reservoir, Tennessee, 1978. [Morone saxatilis

Energy Technology Data Exchange (ETDEWEB)

Schaich, B.A.; Coutant, C.C.

1980-08-01

Habitat selection of 31 adult striped bass was monitored by temperature sensing ultrasonic and radio transmitters in Cherokee Reservoir, Tennessee, from March through October 1978. This study sought to corroborate summer data obtained by Waddle (1979) in 1977 and to examine mechanisms of habitat selection by observing establishment of the summer distribution. During the spring and early summer months the striped bass ranged throughout the study area in the downstream half of the reservoir. Fish stayed near the bottom at the preferred temperatures throughout the whole study, and no individuals were observed in open water. Movement rates of up to 2.6 km/day were estimated, and rates of 1 km/day were common in the spring. By late July they were apparently avoiding low dissolved oxygen (D.O.) concentrations (<3 mg/l) near the bottom of the main reservoir and epilimnion temperatures greater than 22/sup 0/C, and they moved into cool, oxygenated spring or creek channels (refuges). Low movement rates of 0 to 25 m/day within these refuges occurred. The rates of the few migrations between refuges could not be estimated. Tagged fish moved out of the refuges 3 to 4 weeks after the fall overturn when reservoir temperatures approximated 22 to 24/sup 0/C.

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

2015-01-01

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. Key Points: 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 PMID

Experimental Design of a Polymeric Solution to Improve the Mobility Ratio in a Reservoir previous implementation of a pilot project of EOR

Directory of Open Access Journals (Sweden)

Vanessa Cuenca

2016-12-01

Full Text Available This paper describes experimental formulations of polymeric solutions through lab evaluations with the objective of finding optimum solution concentration to fluid mobility in reservoirs as previous step before implementing a pilot project of enhanced oil recovery. The polymers, firstly, were selected based on the properties from fluids from reservoir. Two types of polymers were used TCC-330 and EOR909 and the experimental tests were: thermal stability, compatibility, adsorption, salinity, and displacement. The design with the best results was with polymer TCC-330 at 1,500 ppm concentration.

Rock music : a living legend of simulation modelling solves a reservoir problem by playing a different tune

Energy Technology Data Exchange (ETDEWEB)

Cope, G.

2008-07-15

Tight sand gas plays are low permeability reservoirs that have contributed an output of 5.7 trillion cubic feet of natural gas per year in the United States alone. Anadarko Petroleum Corporation has significant production from thousands of wells in Texas, Colorado, Wyoming and Utah. Hydraulic fracturing is the key to successful tight sand production. Production engineers use modelling software to calculate a well stimulation program in which large volumes of water are forced under high pressure in the reservoir, fracturing the rock and creating high permeability conduits for the natural gas to escape. Reservoir engineering researchers at the University of Calgary, led by world expert Tony Settari, have improved traditional software modelling of petroleum reservoirs by combining fracture analysis with geomechanical processes. This expertise has been a valuable asset to Anadarko, as the dynamic aspect can have a significant effect on the reservoir as it is being drilled. The challenges facing reservoir simulation is the high computing time needed for analyzing fluid production based on permeability, porosity, gas and fluid properties along with geomechanical analysis. Another challenge has been acquiring high quality field data. Using Anadarko's field data, the University of Calgary researchers found that water fracturing creates vertical primary fractures, and in some cases secondary fractures which enhance permeability. However, secondary fracturing is not permanent in all wells. The newly coupled geomechanical model makes it possible to model fracture growth more accurately. The Society of Petroleum Engineers recently awarded Settari with an award for distinguished achievement in improving the technique and practice of finding and producing petroleum. 1 fig.

A fully-coupled discontinuous Galerkin spectral element method for two-phase flow in petroleum reservoirs

Science.gov (United States)

Taneja, Ankur; Higdon, Jonathan

2018-01-01

A high-order spectral element discontinuous Galerkin method is presented for simulating immiscible two-phase flow in petroleum reservoirs. The governing equations involve a coupled system of strongly nonlinear partial differential equations for the pressure and fluid saturation in the reservoir. A fully implicit method is used with a high-order accurate time integration using an implicit Rosenbrock method. Numerical tests give the first demonstration of high order hp spatial convergence results for multiphase flow in petroleum reservoirs with industry standard relative permeability models. High order convergence is shown formally for spectral elements with up to 8th order polynomials for both homogeneous and heterogeneous permeability fields. Numerical results are presented for multiphase fluid flow in heterogeneous reservoirs with complex geometric or geologic features using up to 11th order polynomials. Robust, stable simulations are presented for heterogeneous geologic features, including globally heterogeneous permeability fields, anisotropic permeability tensors, broad regions of low-permeability, high-permeability channels, thin shale barriers and thin high-permeability fractures. A major result of this paper is the demonstration that the resolution of the high order spectral element method may be exploited to achieve accurate results utilizing a simple cartesian mesh for non-conforming geological features. Eliminating the need to mesh to the boundaries of geological features greatly simplifies the workflow for petroleum engineers testing multiple scenarios in the face of uncertainty in the subsurface geology.

Hydrodynamic modeling of petroleum reservoirs using simulator MUFITS

Science.gov (United States)

Afanasyev, Andrey

2015-04-01

MUFITS is new noncommercial software for numerical modeling of subsurface processes in various applications (www.mufits.imec.msu.ru). To this point, the simulator was used for modeling nonisothermal flows in geothermal reservoirs and for modeling underground carbon dioxide storage. In this work, we present recent extension of the code to petroleum reservoirs. The simulator can be applied in conventional black oil modeling, but it also utilizes a more complicated models for volatile oil and gas condensate reservoirs as well as for oil rim fields. We give a brief overview of the code by providing the description of internal representation of reservoir models, which are constructed of grid blocks, interfaces, stock tanks as well as of pipe segments and pipe junctions for modeling wells and surface networks. For conventional black oil approach, we present the simulation results for SPE comparative tests. We propose an accelerated compositional modeling method for sub- and supercritical flows subjected to various phase equilibria, particularly to three-phase equilibria of vapour-liquid-liquid type. The method is based on the calculation of the thermodynamic potential of reservoir fluid as a function of pressure, total enthalpy and total composition and storing its values as a spline table, which is used in hydrodynamic simulation for accelerated PVT properties prediction. We provide the description of both the spline calculation procedure and the flashing algorithm. We evaluate the thermodynamic potential for a mixture of two pseudo-components modeling the heavy and light hydrocarbon fractions. We develop a technique for converting black oil PVT tables to the potential, which can be used for in-situ hydrocarbons multiphase equilibria prediction under sub- and supercritical conditions, particularly, in gas condensate and volatile oil reservoirs. We simulate recovery from a reservoir subject to near-critical initial conditions for hydrocarbon mixture. We acknowledge

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 (CO...... 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....

Comparison of the diagenetic and reservoir quality evolution between the anticline crest and flank of an Upper Jurassic carbonate gas reservoir, Abu Dhabi, United Arab Emirates

Science.gov (United States)

Morad, Daniel; Nader, Fadi H.; Gasparrini, Marta; Morad, Sadoon; Rossi, Carlos; Marchionda, Elisabetta; Al Darmaki, Fatima; Martines, Marco; Hellevang, Helge

2018-05-01

This petrographic, stable isotopic and fluid inclusion microthermometric study of the Upper Jurassic limestones of an onshore field, Abu Dhabi, United Arab Emirates (UAE) compares diagenesis in flanks and crest of the anticline. The results revealed that the diagenetic and related reservoir quality evolution occurred during three phases, including: (i) eogenesis to mesogenesis 1, during which reservoir quality across the field was either deteriorated or preserved by calcite cementation presumably derived from marine or evolved marine pore waters. Improvement of reservoir quality was due to the formation of micropores by micritization of allochems and creation of moldic/intragranular pores by dissolution of peloids and skeletal fragments. (ii) Obduction of Oman ophiolites and formation of the anticline of the studied field was accompanied by cementation by saddle dolomite and blocky calcite. High homogenization temperatures (125-175 °C) and high salinity (19-26 wt% NaCl eq) of the fluid inclusions, negative δ18OVPDB values (-7.7 to -2.9‰), saddle shape of dolomite, and the presence of exotic cements (i.e. fluorite and sphalerite) suggest that these carbonates were formed by flux of hot basinal brines, probably related to this tectonic compression event. (iii) Mesogenesis 2 during subsidence subsequent to the obduction event, which resulted in extensive stylolitization and cementation by calcite. This calcite cement occluded most of the remaining moldic and inter-/intragranular pores of the flank limestones (water zone) whereas porosity was preserved in the crest. This study contributes to: (1) our understanding of differences in the impact of diagenesis on reservoir quality evolution in flanks and crests of anticlines, i.e. impact of hydrocarbon emplacement on diagenesis, and (2) relating various diagenetic processes to burial history and tectonic events of foreland basins in the Arabian Gulf area and elsewhere.

A coupled reaction and transport model for assessing the injection, migration and fate of waste fluids

International Nuclear Information System (INIS)

Liu, X.; Ortoleva, P.

1996-01-01

The use of reaction-transport modeling for reservoir assessment and management in the context of deep well waste injection is evaluated. The study is based on CIRF.A (Chemical Interaction of Rock and Fluid), a fully coupled multiphase flow, contaminant transport, and fluid and mineral reaction model. Although SWIFT (Sandia Waste-Isolation Flow and Transport Model) is often the numerical model of choice, it can not account for chemical reactions involving rock, wastes, and formation fluids and their effects on contaminant transport, rock permeability and porosity, and the integrity of the reservoir and confining units. CIRF.A can simulate all these processes. Two field cases of waste injection were simulated by CIRF.A. Both observation data and simulation results show mineral precipitation in one case and rock dissolution in another case. Precipitation and dissolution change rock porosity and permeability, and hence the pattern of fluid migration. The model is shown to be invaluable in analyzing near borehole and reservoir-scale effects during waste injection and predicting the 10,000 year fate of the waste plume. The benefits of using underpressured compartments as waste repositories were also demonstrated by CIRF.A simulations

Effect of Discrete Fracture Network Characteristics on the Sustainability of Heat Production in Enhanced Geothermal Reservoirs

Science.gov (United States)

Riahi, A.; Damjanac, B.

2013-12-01

Viability of an enhanced or engineered geothermal reservoir is determined by the rate of produced fluid at production wells and the rate of temperature drawdown in the reservoir as well as that of the produced fluid. Meeting required targets demands sufficient permeability and flow circulation in a relatively large volume of rock mass. In-situ conditions such overall permeability of the bedrock formation, magnitude and orientation of stresses, and the characteristics of the existing Discrete Fracture Network (DFN) greatly affect sustainable heat production. Because much of the EGS resources are in formations with low permeability, different stimulation techniques are required prior to the production phase to enhance fluid circulation. Shear stimulation or hydro-shearing is the method of injecting a fluid into the reservoir with the aim of increasing the fluid pressure in the naturally fractured rock and inducing shear failure or slip events. This mechanism can enhance the system's permeability through permanent dilatational opening of the sheared fractures. Using a computational modeling approach, the correlation between heat production and DFN statistical characteristics, namely the fracture length distribution, fracture orientation, and also fracture density is studied in this paper. Numerical analyses were completed using two-dimensional distinct element code UDEC (Itasca, 2011), which represents rock masses as an assembly of interacting blocks separated by fractures. UDEC allows for simulation of fracture propagation along the predefined planes only (i.e., the trajectory of the hydraulic fracture is not part of the solution of the problem). Thus, the hydraulic fracture is assumed to be planar, aligned with the direction of the major principal stress. The pre-existing fractures were represented explicitly. They are discontinuities which deform elastically, but also can open and slip (Coulomb slip law) as a function of pressure and total stress changes. The fluid

EOS simulation and GRNN modeling of the constant volume depletion behavior of gas condensate reservoirs

Energy Technology Data Exchange (ETDEWEB)

Elsharkawy, A.M.; Foda, S.G. [Kuwait University, Safat (Kuwait). Petroleum Engineering Dept.

1998-03-01

Currently, two approaches are being used to predict the changes in retrograde gas condensate composition and estimate the pressure depletion behavior of gas condensate reservoirs. The first approach uses the equation of states whereas the second uses empirical correlations. Equations of states (EOS) are poor predictive tools for complex hydrocarbon systems. The EOS needs adjustment against phase behavior data of reservoir fluid of known composition. The empirical correlation does not involve numerous numerical computations but their accuracy is limited. This study presents two general regression neural network (GRNN) models. The first model, GRNNM1, is developed to predict dew point pressure and gas compressibility at dew point using initial composition of numerous samples while the second model, GRNNM2, is developed to predict the changes in well stream effluent composition at any stages of pressure depletion. GRNNM2 can also be used to determine the initial reservoir fluid composition using dew point pressure, gas compressibility at dew point, and reservoir temperature. These models are based on analysis of 142 sample of laboratory studies of constant volume depletion (CVD) for gas condensate systems forming a total of 1082 depletion stages. The database represents a wide range of gas condensate systems obtained worldwide. The performance of the GRNN models has been compared to simulation results of the equation of state. The study shows that the proposed general regression neural network models are accurate, valid, and reliable. These models can be used to forecast CVD data needed for many reservoir engineering calculations in case laboratory data is unavailable. The GRNN models save computer time involved in EOS calculations. The study also show that once these models are properly trained they can be used to cut expenses of frequent sampling and laborious experimental CVD tests required for gas condensate reservoirs. 55 refs., 13 figs., 6 tabs.

Simulation of a SAGD well blowout using a reservoir-wellbore coupled simulator

Energy Technology Data Exchange (ETDEWEB)

Walter, J.; Vanegas, P.; Cunha, L.B. [Alberta Univ., Edmonton, AB (Canada); Worth, D.J. [C-FER Technologies, Edmonton, AB (Canada); Crepin, S. [Petrocedeno, Caracas (Venezuela)

2008-10-15

Single barrier completion systems are typically used in SAGD projects due to the lack of equipment suitable for high temperature SAGD downhole environments. This study used a wellbore and reservoir coupled thermal simulator tool to investigate the blowout behaviour of a steam assisted gravity drainage (SAGD) well pair when the safety barrier has failed. Fluid flow pressure drop through the wellbore and heat losses between the wellbore and the reservoir were modelled using a discretized wellbore option and a semi-analytical model. The fully coupled mechanistic model accounted for the simultaneous transient pressure and temperature variations along the wellbore and the reservoir. The simulations were used to predict flowing potential and fluid compositions of both wells in a SAGD well pair under various flowing conditions. Blowout scenarios were created for 3 different points in the well pair's life. Three flow paths during the blowout were evaluated for both the production and injection wells. Results of the study were used to conduct a comparative risk assessment between a double barrier and a single barrier completion. The modelling study confirmed that both the injection and production wells had the potential for blowouts lasting significant periods of time, with liquid rates over 50 times the normal production liquid rates. The model successfully predicted the blowout flow potential of the SAGD well pairs. 8 refs., 3 tabs., 18 figs.

Using microstructure observations to quantify fracture properties and improve reservoir simulations. Final report, September 1998

Energy Technology Data Exchange (ETDEWEB)

Laubach, S.E.; Marrett, R.; Rossen, W.; Olson, J.; Lake, L.; Ortega, O.; Gu, Y.; Reed, R.

1999-01-01

The research for this project provides new technology to understand and successfully characterize, predict, and simulate reservoir-scale fractures. Such fractures have worldwide importance because of their influence on successful extraction of resources. The scope of this project includes creation and testing of new methods to measure, interpret, and simulate reservoir fractures that overcome the challenge of inadequate sampling. The key to these methods is the use of microstructures as guides to the attributes of the large fractures that control reservoir behavior. One accomplishment of the project research is a demonstration that these microstructures can be reliably and inexpensively sampled. Specific goals of this project were to: create and test new methods of measuring attributes of reservoir-scale fractures, particularly as fluid conduits, and test the methods on samples from reservoirs; extrapolate structural attributes to the reservoir scale through rigorous mathematical techniques and help build accurate and useful 3-D models of the interwell region; and design new ways to incorporate geological and geophysical information into reservoir simulation and verify the accuracy by comparison with production data. New analytical methods developed in the project are leading to a more realistic characterization of fractured reservoir rocks. Testing diagnostic and predictive approaches was an integral part of the research, and several tests were successfully completed.

A Multi-physics Approach to Understanding Low Porosity Soils and Reservoir Rocks

Science.gov (United States)

Prasad, M.; Mapeli, C.; Livo, K.; Hasanov, A.; Schindler, M.; Ou, L.

2017-12-01

We present recent results on our multiphysics approach to rock physics. Thus, we evaluate geophysical measurements by simultaneously measuring petrophysical properties or imaging strains. In this paper, we present simultaneously measured acoustic and electrical anisotropy data as functions of pressure. Similarly, we present strains and strain localization images simultaneously acquired with acoustic measurements as well as NMR T2 relaxations on pressurized fluids as well as rocks saturated with these pressurized fluids. Such multiphysics experiments allow us to constrain and assign appropriate causative mechanisms to development rock physics models. They also allow us to decouple various effects, for example, fluid versus pressure, on geophysical measurements. We show applications towards reservoir characterization as well as CO2 sequestration applications.

Evaluation of MRI issues for a new neurological implant, the Sensor Reservoir.

Science.gov (United States)

Shellock, Frank G; Knebel, Jörg; Prat, Angelina D

2013-09-01

A new neurological implant, the Sensor-Reservoir, was developed to provide a relative measurement of ICP, which permits a noninvasive technique to detect and localize occlusions in ventricular drainage systems and, thus, to identify mechanical damage to shunt valves. The "reservoir" of this device can be used to administer medication or a contrast agent, to extract cerebral spinal fluid (CSF), and with the possibility of directly measuring ICP. The Sensor-Reservoir was evaluated to identify possible MRI-related issues at 1.5-T/64-MHz and 3-T/128-MHz. Standard testing techniques were utilized to evaluate magnetic field interactions (i.e., translational attraction and torque), MRI-related heating, and artifacts at 3-T for the Sensor-Reservoir. In addition, 12 samples of the Sensor-Reservoir underwent testing to determine if the function of these devices was affected by exposures to various MRI conditions at 1.5-T/64-MHz and 3-T/128-MHz. Magnetic field interactions for the Sensor-Reservoir were not substantial. The heating results indicated a highest temperature rise of 1.8 °C, which poses no patient risks. Artifacts were relatively small in relation to the size and shape of the Sensor-Reservoir, but may interfere diagnostically if the area of interest is near the device. All devices were unaffected by exposures to MRI conditions at 1.5-T/64-MHz and 3-T/128-MHz. When specific guidelines are followed, the Sensor-Reservoir is "MR conditional" for patients undergoing MRI examinations at 3-T or less. Copyright © 2013 Elsevier Inc. All rights reserved.

Fortescue reservoir development and reservoir studies

Energy Technology Data Exchange (ETDEWEB)

Henzell, S.T.; Hicks, G.J.; Horden, M.J.; Irrgang, H.R.; Janssen, E.J.; Kable, C.W.; Mitchell, R.A.H.; Morrell, N.W.; Palmer, I.D.; Seage, N.W.

1985-03-01

The Fortescue field in the Gippsland Basin, offshore southeastern Australia is being developed from two platforms (Fortescue A and Cobia A) by Esso Australia Ltd. (operator) and BHP Petroleum. The Fortescue reservoir is a stratigraphic trap at the top of the Latrobe Group of sediments. It overlies the western flank of the Halibut and Cobia fields and is separated from them by a non-net sequence of shales and coals which form a hydraulic barrier between the two systems. Development drilling into the Fortescue reservoir commenced in April 1983 with production coming onstream in May 1983. Fortescue, with booked reserves of 44 stock tank gigalitres (280 million stock tank barrels) of 43/sup 0/ API oil, is the seventh major oil reservoir to be developed in the offshore Gippsland Basin by Esso/BHP. In mid-1984, after drilling a total of 20 exploration and development wells, and after approximately one year of production, a detailed three-dimensional, two-phase reservoir simulation study was performed to examine the recovery efficiency, drainage patterns, pressure performance and production rate potential of the reservoir. The model was validated by history matching an extensive suite of Repeat Formation Test (RFT) pressure data. The results confirmed the reserves basis, and demonstrated that the ultimate oil recovery from the reservoir is not sensitive to production rate. This result is consistent with studies on other high quality Latrobe Group reservoirs in the Gippsland Basin which contain undersaturated crudes and receive very strong water drive from the Basin-wide aquifer system. With the development of the simulation model during the development phase, it has been possible to more accurately define the optimal well pattern for the remainder of the development.

Monitoring of Corrientes facility using nuclear registers techniques

International Nuclear Information System (INIS)

Yesquen L, S.

1994-01-01

Knowledge of fluid movement in the reservoir is a key to enhanced production management. Direct measurement of water and oil saturation variations with time, is the most reliable method in determining the depletion profile of reservoirs with ample range of permeabilities. This paper illustrates how nuclear logging techniques aids proper management in strong water drive reservoir named Cetico Corrientes Field, in east Peru. Important production increase was obtained with work over and drilling program, based on reservoir monitoring using thermal decay tool. (author). 7 figs

Pulsed Neutron log application in accurate fluid contact determination and remedial action planning

International Nuclear Information System (INIS)

Kalu, I.; Mukerji, P.

2002-01-01

A common application of pulsed neutron logging in the Niger Delta is saturation monitoring when run in carbon-oxygen (CO) mode. Recently, one such log was run across a reservoir to confirm the position of the oil-water contact on a well that was producing at very high water cut on the short string of a dual string producer. Material balance calculations had predicted an oil-water contact about 5ft from the deepest perforations and so a water shut-off operation had been planned. The interpreted log however showed that the OWC was about 30ft from the perforation and it also showed fluid movement in the borehole in front of the perforations. A production log was subsequently run which identified a tubing leak and confirmed the crossflow of water from the long string into the short string detected on the pulsed neutron log. The proposed water shut-off treatment was aborted based on the interpretation and resulted in substantial savings

Cross-fault pressure depletion, Zechstein carbonate reservoir, Weser-Ems area, Northern German Gas Basin

Energy Technology Data Exchange (ETDEWEB)

Corona, F.V.; Brauckmann, F.; Beckmann, H.; Gobi, A.; Grassmann, S.; Neble, J.; Roettgen, K. [ExxonMobil Production Deutschland GmbH (EMPG), Hannover (Germany)

2013-08-01

A cross-fault pressure depletion study in Upper Permian Zechstein Ca2 carbonate reservoir was undertaken in the Weser-Ems area of the Northern German Gas Basin. The primary objectives are to develop a practical workflow to define cross-fault pressures scenarios for Zechstein Ca2 reservoir drillwells, to determine the key factors of cross-fault pressure behavior in this platform carbonate reservoir, and to translate the observed cross-fault pressure depletion to fault transmissibility for reservoir simulation models. Analysis of Zechstein Ca2 cross-fault pressures indicates that most Zechstein-cutting faults appear to act as fluid-flow baffles with some local occurrences of fault seal. Moreover, there appears to be distinct cross-fault baffling or pressure depletion trends that may be related to the extent of the separating fault or fault system, degree of reservoir flow-path tortuosity, and quality of reservoir juxtaposition. Based on the above observations, a three-part workflow was developed consisting of (1) careful interpretation and mapping of faults and fault networks, (2) analysis of reservoir juxtaposition and reservoir juxtaposition quality, and (3) application of the observed cross-fault pressure depletion trends. This approach is field-analog based, is practical, and is being used currently to provide reliable and supportable pressure prediction scenarios for subsequent Zechstein fault-bounded drill-well opportunities.

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.

MAPPING OF RESERVOIR PROPERTIES AND FACIES THROUGH INTEGRATION OF STATIC AND DYNAMIC DATA

Energy Technology Data Exchange (ETDEWEB)

Albert C. Reynolds; Dean S. Oliver; Yannong Dong; Ning Liu; Guohua Gao; Fengjun Zhang; Ruijian Li

2004-12-01

Knowledge of the distribution of permeability and porosity in a reservoir is necessary for the prediction of future oil production, estimation of the location of bypassed oil, and optimization of reservoir management. The volume of data that can potentially provide information on reservoir architecture and fluid distributions has increased enormously in the past decade. The techniques developed in this research will make it easier to use all the available data in an integrated fashion. While it is relatively easy to generate plausible reservoir models that honor static data such as core, log, and seismic data, it is far more difficult to generate plausible reservoir models that honor dynamic data such as transient pressures, saturations, and flow rates. As a result, the uncertainty in reservoir properties is higher than it could be and reservoir management can not be optimized. In this project, we have developed computationally efficient automatic history matching techniques for generating geologically plausible reservoir models which honor both static and dynamic data. Specifically, we have developed methods for adjusting porosity and permeability fields to match both production and time-lapse seismic data and have also developed a procedure to adjust the locations of boundaries between facies to match production data. In all cases, the history matched rock property fields are consistent with a prior model based on static data and geologic information. Our work also indicates that it is possible to adjust relative permeability curves when history matching production data.

Detailed geologic modeling of a turbidity reservoir interval at the Mars discovery

Energy Technology Data Exchange (ETDEWEB)

Mahaffie, M.J.; Chapin, M.A. [Shell Exploration and Production Technology Co. (United States); Henry, W.A. [Shell Offshore, Inc. (United States)

1995-12-31

Detailed reservoir architecture studies using high resolution seismic data coupled with geologic and seismic inversion modeling have been used to evaluate a major hydrocarbon bearing turbidite reservoir found within Prospect Mars. Early interpretations of this interval, based on lower frequency (40 Hz) seismic data, indicated the presence of a single, laterally continuous event covering an area nearly 3 miles square ({approx} 5200 acres). Correlations from well control supported the notion that this seismic event comprised a series of continuous sheet sands exhibiting a high degree of lateral continuity and connectivity. However pressure data taken during fluid sampling of the reservoir suggested the possibility of discontinuities not observed within the resolution of the seismic data. Seismic reprocessing enhancements to increase frequency content revealed the presence of multiple stratigraphic features not previously recognized. Detailed seismic mapping using loop-level seismic attributes and seismic inversion studies constrained by geologic models provide a more realistic depiction of the environment of deposition and improve reservoir simulation modeling for this stratigraphic interval. (author). 3 figs

Characterization of deep-marine clastic sediments from foreland basins: Outcrop-derived concepts for exploration, production and reservoir modelling. Doctoral thesis; Karakterizering van diep-mariene klastische sedimenten uit voorland bekkens: Aan ontsluitingen ontleende concepten voor exploratie, produktie en reservoir modellering

Energy Technology Data Exchange (ETDEWEB)

Schuppers, J D

1995-02-20

Deep-marine clastic sediments are the host for many prolific hydrocarbon reservoirs. The sandbodies that form these reservoirs show a wide variety in shape, spatial arrangement, and internal structure. The outcrops studied for this thesis pertain to the fill of circum-mediterranean foreland basins in Spain and Greece. The outcrops have allowed the description of the multiscale anatomy of sandbodies that cover a wide range of depositional settings. The descriptions are focused on those features that are most likely to influence the flow of fluids through analogous reservoirs of similar construction. Extensive use was made of photomosaics to outline the large-scale geometries and stacking modes of the sandbodies. The sediments studied form the basis for seven `reservoir models` that are both descriptive and conceptual.

Reservoir compartmentalization and management strategies: Lessons learned in the Illinois basin

Energy Technology Data Exchange (ETDEWEB)

Grube, J.P.; Crockett, J.E.; Huff, B.G. [and others

1997-08-01

A research project jointly sponsored by the US Department of Energy and the Illinois State Geological Survey focused on the Cypress and Aux Vases Formations (Mississippian), major clastic reservoirs in the Illinois Basin. Results from the research showed that understanding the nature and distribution of reservoir compartments, and using effective reservoir management strategies, can significantly improve recovery efficiencies from oil fields in this mature basin. Compartments can be most effectively drained where they are geologically well defined and reservoir management practices are coordinated through unified, compartment-wide, development programs. Our studies showed that the Cypress and Aux Vases reservoirs contain lateral and vertical permeability barriers forming compartments that range in size from isolated, interlaminated sandstone and shale beds to sandstone bodies tens of feet in thickness and more than a mile in length. Stacked or shingled, genetically similar sandstone bodies are commonly separated by thin impermeable intervals that can be difficult to distinguish on logs and can, therefore, cause correlation problems, even between wells drilled on spacing of less than ten acres. Lateral separation of sandstone bodies causes similar problems. Reservoir compartmentalization reduces primary and particularly secondary recovery by trapping pockets of by-passed or banked oil. Compartments can be detected by comparing recovery factors of genetically similar sandstone bodies within a field; using packers to separate commingled intervals and analyzing fluid recoveries and pressures; making detailed core-to-log calibrations that identify compartment boundaries; and analyzing pressure data from waterflood programs.

Development of a neural fuzzy system for advanced prediction of dew point pressure in gas condensate reservoirs

Energy Technology Data Exchange (ETDEWEB)

Nowroozi, Saeed; Hashemipour, Hasan; Schaffie, Mahin [Department of Chemical Engineering, Shahid Bahonar University of Kerman (Iran); ERC, Shahid Bahonar University of Kerman (Iran); Ranjbar, Mohammad [Department of Mining Engineering, Shahid Bahonar University of Kerman (Iran); ERC, Shahid Bahonar University of Kerman (Iran)

2009-03-15

Dew point pressure is one of the most critical quantities for characterizing a gas condensate reservoir. So, accurate determination of this property has been the main challenge in reservoir development and management. The experimental determination of dew point pressure in PVT cell is often difficult especially in case of lean retrograde gas condensate. Empirical correlations and some equations of state can be used to calculate reservoir fluid properties. Empirical correlations do not have ability to reliable duplicate the temperature behavior of constant composition fluids. Equations of state have convergence problem and need to be tuned against some experimental data. Complexity, non-linearity and vagueness are some reservoir parameter characteristic which can be propagated simply by intelligent system. With the advantage of fuzzy sets in knowledge representation and the high capacity of neural nets (NNs) in learning knowledge expressed in data, in this paper a neural fuzzy system(NFS) is proposed to predict dew point pressure of gas condensate reservoir. The model was developed using 110 measurements of dew point pressure. The performance of the model is compared against performance of some of the most accurate and general correlations for dew point pressure calculation. From the results of this study, it can be pointed out that this novel method is more accurate and reliable with the mean square error of 0.058%, 0.074% and 0.044% for training, validation and test processes, respectively. (author)

Behavior and dam passage of juvenile Chinook salmon at Cougar Reservoir and Dam, Oregon, March 2011 - February 2012

Science.gov (United States)

Beeman, John W.; Hansel, Hal C.; Hansen, Amy C.; Haner, Philip V.; Sprando, Jamie M.; Smith, Collin D.; Evans, Scott D.; Hatton, Tyson W.

2013-01-01

The movements and dam passage of juvenile Chinook salmon implanted with acoustic transmitters and passive integrated transponder tags were studied at Cougar Reservoir and Dam, near Springfield, Oregon. The purpose of the study was to provide information to aid with decisions about potential alternatives for improving downstream passage conditions for juvenile salmonids in this flood-control reservoir. In 2011, a total of 411 hatchery fish and 26 wild fish were tagged and released during a 3-month period in the spring, and another 356 hatchery fish and 117 wild fish were released during a 3-month period in the fall. A series of 16 autonomous hydrophones throughout the reservoir and 12 hydrophones in a collective system near the dam outlet were used to determine general movements and dam passage of the fish over the life of the acoustic transmitter, which was expected to be about 3 months. Movements within the reservoir were directional, and it was common for fish to migrate repeatedly from the head of the reservoir downstream to the dam outlet and back to the head of the reservoir. Most fish were detected near the temperature control tower at least once. The median time from release near the head of the reservoir to detection within about 100 meters of the dam outlet at the temperature control tower was between 5.7 and 10.8 days, depending on season and fish origin. Dam passage events occurred over a wider range of dates in the spring and summer than in the fall and winter, but dam passage numbers were greatest during the fall and winter. A total of 10.5 percent (43 of 411) of the hatchery fish and 15.4 percent (4 of 26) of the wild fish released in the spring are assumed to have passed the dam, whereas a total of 25.3 percent (90 of 356) of the hatchery fish and 16.9 percent (30 of 117) of the wild fish released in the fall are assumed to have passed the dam. A small number of fish passed the dam after their transmitters had stopped working and were detected at

The fluid inclusion study in petroleum exploration; O estudo de inclusoes fluidas na exploracao de petroleo

Energy Technology Data Exchange (ETDEWEB)

Coelho, Carlos Eduardo Silva [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Gerencia da Geoquimica]. E-mail: cescoelho@petrobras.com.br

2005-05-01

Several oil companies and research centers have been studying petroleum fluid inclusions in reservoirs since the 1980's. The first works have used the fluid inclusion microthermometry technique in order to interpret the thermal history and petroleum migration in relation to the burial history and diagenesis. Lately, the micro thermometric data is being used as a calibration parameter for thermal history modeling in sedimentary basins and reservoirs. Recently, new fluid inclusion study techniques are being used in petroleum exploration. Geochemical data of low molecular weight (up to C{sub 15}) oil-bearing fluid inclusions has been used with the purpose of pinpointing oil-bearing intervals in wells that have not revealed the presence of oil by conventional techniques. Molecular geochemical analyses of oils inside the inclusions technique enable oil-source correlations, oil-oil correlations, and maturity determination. (author)

Veins in Paleo-reservoir as a Natural Indication of Coupled Changes in Pore Pressure and Stress, Salt Wash Graben of SE Utah, USA

Science.gov (United States)

Gwon, S.; Edwards, P.; Kim, Y. S.

2015-12-01

Hydrofracturing associated with elevated fluid pressure coupled with changes in stress has been crucial in enhancing the production and recovery of hydrocarbons. Furthermore, it is also an important issue to access the efficiency and stability of long-term CO2 geologic storage reservoirs. Veins are mineral-filled extension fractures developed along the plane of σ1-σ2 and perpendicular to σ3, and the fluid pressure must exceed σ3applied to the plane when the vein opens. Therefore, vein is a well-known natural analogue for fluid migration in a paleo-reservoir. In the Salt Wash Graben of SE Utah, CO2-charged vein systems hosted in the bleached Entrada Formation are well developed and examined to understand the conditions of fluid pressure and stress during the injections of CO2-charged fluid. Based on color and relative cross-cutting relationship in the field, veins are subdivided into two sets; sub-vertical black mineral-rich veins and orthogonal calcite veins that have previously been described as 'grid-lock fractures'. The vein distribution and fluid leakage along through-going fractures in mechanic units allow us to determine the stress regime and driving stress condition through 3D-Mohr circle reconstruction. The results of this statistical analysis for the veins show that the orthogonal veins indicate a 'stress transition' with maximum principal stress direction changing from vertical to NNW-SSE sub-horizontal which coincides with the current regional stress regime. The possible causes of the stress transition can be considered. The process of repeated sealing, reactivation and localization of veins within the bleached zone is a natural indication of a coupled change in pore pressure and stress in the reservoir. Thus, an understanding of the effect of stress changes due to the volumetric injection of CO2 in the subsurface as well as a knowledge of how pre-existing fractures affect fluid flow with respect to elevated pore pressures in layered rocks are

Integration of 3D photogrammetric outcrop models in the reservoir modelling workflow

Science.gov (United States)

Deschamps, Remy; Joseph, Philippe; Lerat, Olivier; Schmitz, Julien; Doligez, Brigitte; Jardin, Anne

2014-05-01

3D technologies are now widely used in geosciences to reconstruct outcrops in 3D. The technology used for the 3D reconstruction is usually based on Lidar, which provides very precise models. Such datasets offer the possibility to build well-constrained outcrop analogue models for reservoir study purposes. The photogrammetry is an alternate methodology which principles are based in determining the geometric properties of an object from photographic pictures taken from different angles. Outcrop data acquisition is easy, and this methodology allows constructing 3D outcrop models with many advantages such as: - light and fast acquisition, - moderate processing time (depending on the size of the area of interest), - integration of field data and 3D outcrops into the reservoir modelling tools. Whatever the method, the advantages of digital outcrop model are numerous as already highlighted by Hodgetts (2013), McCaffrey et al. (2005) and Pringle et al. (2006): collection of data from otherwise inaccessible areas, access to different angles of view, increase of the possible measurements, attributes analysis, fast rate of data collection, and of course training and communication. This paper proposes a workflow where 3D geocellular models are built by integrating all sources of information from outcrops (surface picking, sedimentological sections, structural and sedimentary dips…). The 3D geomodels that are reconstructed can be used at the reservoir scale, in order to compare the outcrop information with subsurface models: the detailed facies models of the outcrops are transferred into petrophysical and acoustic models, which are used to test different scenarios of seismic and fluid flow modelling. The detailed 3D models are also used to test new techniques of static reservoir modelling, based either on geostatistical approaches or on deterministic (process-based) simulation techniques. A modelling workflow has been designed to model reservoir geometries and properties from

Tracing Geothermal Fluids

Energy Technology Data Exchange (ETDEWEB)

Michael C. Adams; Greg Nash

2004-03-01

Geothermal water must be injected back into the reservoir after it has been used for power production. Injection is critical in maximizing the power production and lifetime of the reservoir. To use injectate effectively the direction and velocity of the injected water must be known or inferred. This information can be obtained by using chemical tracers to track the subsurface flow paths of the injected fluid. Tracers are chemical compounds that are added to the water as it is injected back into the reservoir. The hot production water is monitored for the presence of this tracer using the most sensitive analytic methods that are economically feasible. The amount and concentration pattern of the tracer revealed by this monitoring can be used to evaluate how effective the injection strategy is. However, the tracers must have properties that suite the environment that they will be used in. This requires careful consideration and testing of the tracer properties. In previous and parallel investigations we have developed tracers that are suitable from tracing liquid water. In this investigation, we developed tracers that can be used for steam and mixed water/steam environments. This work will improve the efficiency of injection management in geothermal fields, lowering the cost of energy production and increasing the power output of these systems.

Forming mechanism of the Ordovician karst carbonate reservoirs on the northern slope of central Tarim Basin

Directory of Open Access Journals (Sweden)

Heng Fu

2017-07-01

Full Text Available The Ordovician karst carbonate reservoirs on the northern slope of central Tarim Basin are important oil and gas exploration targets in the basin, but their dissolution mechanisms are in controversy. In this paper, based on the integrated study of sedimentation, sequence and reservoir, together with microscopic analysis and macroscopic seismic data analysis, the carbonate karst reservoirs in the study area were divided into three types: dissolved pore-cavity limestone reservoir, pore-cavity dolomite reservoir and fracture-cavity siliceous reservoir, and their forming mechanisms were discussed respectively. Some findings were obtained. First, dissolved pore-cavity limestone reservoirs are distributed in the upper Yingshan Fm and Yijianfang Fm of the Ordovician vertically, while pore-cavity dolomite reservoirs are mainly developed in the Penglai Fm and lower Yingshan Fm of the Ordovician with great thickness. Second, dissolved pore-cavity limestone reservoirs were formed by karstification on the third-order sequence boundary (lowstand tract, while pore-cavity dolomite reservoirs were formed by deep burial dolomitization controlled by karstification on the third-order sequence boundary, both of which are distributed in the highstand tract below the third-order sequence boundary. Third, siliceous reservoirs are developed under the control of faulting, as a result of reworking of deep hydrothermal fluids along faults to the limestone, and the siliceous reservoirs and their hydrothermal solution fracture-cavity systems are distributed near faults. It is further predicted that, in addition to the three types of reservoir above, platform-margin reef-flat reservoirs are developed in the Ordovician on the northern slope of central Tarim Basin.

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

On Application of Non-cubic EoS to Compositional Reservoir Simulation

DEFF Research Database (Denmark)

Yan, Wei; Michelsen, Michael Locht; Stenby, Erling Halfdan

Compositional reservoir simulation uses almost exclusively cubic equations of state (EoS) such as the SRK EoS and the PR EoS. This is in contrast with process simulation in the downstream industry where more recent and advanced thermodynamic models are quickly adopted. Many of these models are non-cubic...... EoS, such as the PC-SAFT EoS. A major reason for the use of the conventional cubic EoS in reservoir simulation is the concern over computation time. Flash computation is the most time consuming part in compositional reservoir simulation, and the extra complexity of the non-cubic EoS may significantly...... increase the time consumption. In addition to this, the non-cubic EoS also needs a C7+ characterization. The main advantage of the non-cubic EoS is that it provides for a more accurate descrition of fluid properties, and it is therefore of interest to investigate the computational aspects of using...

Simulation study of huff-n-puff air injection for enhanced oil recovery in shale oil reservoirs

Directory of Open Access Journals (Sweden)

Hu Jia

2018-03-01

Full Text Available This paper is the first attempt to evaluate huff-n-puff air injection in a shale oil reservoir using a simulation approach. Recovery mechanisms and physical processes of huff-n-puff air injection in a shale oil reservoir are investigated through investigating production performance, thermal behavior, reservoir pressure and fluid saturation features. Air flooding is used as the basic case for a comparative study. The simulation study suggests that thermal drive is the main recovery mechanism for huff-n-puff air injection in the shale oil reservoir, but not for simple air flooding. The synergic recovery mechanism of air flooding in conventional light oil reservoirs can be replicated in shale oil reservoirs by using air huff-n-puff injection strategy. Reducing huff-n-puff time is better for performing the synergic recovery mechanism of air injection. O2 diffusion plays an important role in huff-n-puff air injection in shale oil reservoirs. Pressure transmissibility as well as reservoir pressure maintenance ability in huff-n-puff air injection is more pronounced than the simple air flooding after primary depletion stage. No obvious gas override is exhibited in both air flooding and air huff-n-puff injection scenarios in shale reservoirs. Huff-n-puff air injection has great potential to develop shale oil reservoirs. The results from this work may stimulate further investigations.

Microtomography and pore-scale modeling of two-phase Fluid Distribution

Energy Technology Data Exchange (ETDEWEB)

Silin, D.; Tomutsa, L.; Benson, S.; Patzek, T.

2010-10-19

Synchrotron-based X-ray microtomography (micro CT) at the Advanced Light Source (ALS) line 8.3.2 at the Lawrence Berkeley National Laboratory produces three-dimensional micron-scale-resolution digital images of the pore space of the reservoir rock along with the spacial distribution of the fluids. Pore-scale visualization of carbon dioxide flooding experiments performed at a reservoir pressure demonstrates that the injected gas fills some pores and pore clusters, and entirely bypasses the others. Using 3D digital images of the pore space as input data, the method of maximal inscribed spheres (MIS) predicts two-phase fluid distribution in capillary equilibrium. Verification against the tomography images shows a good agreement between the computed fluid distribution in the pores and the experimental data. The model-predicted capillary pressure curves and tomography-based porosimetry distributions compared favorably with the mercury injection data. Thus, micro CT in combination with modeling based on the MIS is a viable approach to study the pore-scale mechanisms of CO{sub 2} injection into an aquifer, as well as more general multi-phase flows.

Successful flow testing of a gas reservoir in 3,500 feet of water

International Nuclear Information System (INIS)

Shaughnessy, J.M.; Carpenter, R.S.; Coleman, R.A.; Jackson, C.W.

1992-01-01

The test of Viosca Knoll Block 957 Well No. 1 Sidetrack No. 2 was Amoco Production Co.'s deepest test from a floating rig. Viosca Knoll 957 is 115 miles southeast of New Orleans in 3,500 ft of water. The test, at a record water depth for the Gulf of Mexico, also set a world water-depth record for testing a gas reservoir. Safety to crew and the environmental were top priorities during the planning. A team consisting of drilling, completion, reservoir, and facilities engineers and a foreman were assigned to plan and implement the test. Early planning involved field, service company, and engineering groups. Every effort was made to identify potential problems and to design the system to handle them. This paper reports that the goals of the test were to determine reservoir properties and reservoir limits. Several significant challenges were involved in the well test. The reservoir was gas with a potentially significant condensate yield. The ability to dispose of the large volumes of produced fluids safely without polluting was critical to maintaining uninterrupted flow. Potential shut-in surface pressure was 6,500 psi. Seafloor temperature in 3,500 ft of water was 39 degrees F

Stepping movement analysis of control rod drive mechanism

International Nuclear Information System (INIS)

Xu Yantao; Zu Hongbiao

2013-01-01

Background: Control rod drive mechanism (CRDM) is one of the important safety-related equipment for nuclear power plants. Purpose: The operating parameters of stepping movement, including lifting loads, step distance and step velocity, are all critical design targets. Methods: FEA and numerical simulation are used to analyze stepping movement separately. Results: The motion equations of the movable magnet in stepping movement are established by load analysis. Gravitation, magnetic force, fluid resistance and spring force are all in consideration in the load analysis. The operating parameters of stepping movement are given. Conclusions: The results, including time history curves of force, speed and etc, can positively used in the design of CRDM. (authors)

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.

On the proluminal movement of 3H-androgens across the rat epididymal epithelium

International Nuclear Information System (INIS)

Turner, T.T.; Jones, C.E.; Roddy, M.S.

1989-01-01

3H-Androgens in rat epididymal interstitium have previously been shown to move into the epididymal lumen against a concentration gradient. This is true especially in the caput epididymidis. The present investigation used the technique of in vivo epididymal perifusion and tubule micropuncture to demonstrate that the proluminal movement of 3H-androgens is subject to competitive inhibition (unlabeled testosterone in the perifusion fluid at 10 times and 100 times the concentration of 3H-testosterone significantly reduced proluminal movement of isotope) and is not energy-dependent (1 mM 2,4-dinitrophenol in perifusion fluid did not reduce the proluminal movement of isotope). Additionally, dry-mount autoradiography demonstrated high intraluminal concentrations of isotope relative to interstitial concentrations after caput tubule incubation in 3H-dihydrotestosterone (3H-DHT), and showed that the high intraluminal concentrations of isotope were not dependent on the presence of spermatozoa, i.e. proluminal movement of 3H-androgens was not due to binding to intraluminal spermatozoa. Isolation of caput epididymidal sperm on filters followed by 3H-DHT binding experiments also failed to demonstrate the presence of specific binding of this androgen to spermatozoa. Finally, it was confirmed that electrophoresed epididymal lumen fluid contains a single 3H-DHT binding peak that is at its highest concentration in the caput epididymal fluid. These data are consistent with the conclusion that intraluminal androgen-binding protein is an important factor in transepithelial androgen movement

Analysis of fracture patterns and local stress field variations in fractured reservoirs

Science.gov (United States)

Deckert, Hagen; Drews, Michael; Fremgen, Dominik; Wellmann, J. Florian

2010-05-01

A meaningful qualitative evaluation of permeabilities in fractured reservoirs in geothermal or hydrocarbon industry requires the spatial description of the existing discontinuity pattern within the area of interest and an analysis how these fractures might behave under given stress fields. This combined information can then be used for better estimating preferred fluid pathway directions within the reservoir, which is of particular interest for defining potential drilling sites. A description of the spatial fracture pattern mainly includes the orientation of rock discontinuities, spacing relationships between single fractures and their lateral extent. We have examined and quantified fracture patterns in several outcrops of granite at the Costa Brava, Spain, and in the Black Forest, Germany, for describing reservoir characteristics. For our analysis of fracture patterns we have used photogrammetric methods to create high-resolution georeferenced digital 3D images of outcrop walls. The advantage of this approach, compared to conventional methods for fracture analysis, is that it provides a better 3D description of the fracture geometry as the entity of position, extent and orientation of single fractures with respect to their surrounding neighbors is conserved. Hence for instance, the method allows generating fracture density maps, which can be used for a better description of the spatial distribution of discontinuities in a given outcrop. Using photogrammetric techniques also has the advantage to acquire very large data sets providing statistically sound results. To assess whether the recorded discontinuities might act as fluid pathways information on the stress field is needed. A 3D model of the regional tectonic structure was created and the geometry of the faults was put into a mechanical 3D Boundary Element (BE) Model. The model takes into account the elastic material properties of the geological units and the orientation of single fault segments. The

Wastewater injection and slip triggering: Results from a 3D coupled reservoir/rate-and-state model

Science.gov (United States)

Babazadeh, M.; Olson, J. E.; Schultz, R.

2017-12-01

Seismicity induced by fluid injection is controlled by parameters related to injection conditions, reservoir properties, and fault frictional behavior. We present results from a combined model that brings together injection physics, reservoir dynamics, and fault physics to better explain the primary controls on induced seismicity. We created a 3D fluid flow simulator using the embedded discrete fracture technique and then coupled it with a 3D displacement discontinuity model that uses rate and state friction to model slip events. The model is composed of three layers, including the top-seal, the injection reservoir, and the basement. Permeability is anisotropic (vertical vs horizontal) and along with porosity varies by layer. Injection control can be either rate or pressure. Fault properties include size, 2D permeability, and frictional properties. Several suites of simulations were run to evaluate the relative importance of each of the factors from all three parameter groups. We find that the injection parameters interact with the reservoir parameters in the context of the fault physics and these relations change for different reservoir and fault characteristics, leading to the need to examine the injection parameters only within the context of a particular faulted reservoir. For a reservoir with no flow boundaries, low permeability (5 md), and a fault with high fault-parallel permeability and critical stress, injection rate exerts the strongest control on magnitude and frequency of earthquakes. However, for a higher permeability reservoir (80 md), injection volume becomes the more important factor. Fault permeability structure is a key factor in inducing earthquakes in basement rocks below the injection reservoir. The initial failure state of the fault, which is challenging to assess, can have a big effect on the size and timing of events. For a fault 2 MPa below critical state, we were able to induce a slip event, but it occurred late in the injection history

The Effects of Orthodontic Forces during Canine Retraction Using Self-ligating Brackets on Gingival Crevicular Fluid Enzyme Activity, Canine Movement and Root Resorption

International Nuclear Information System (INIS)

Rohaya Megat Abdul Wahab; Albira Sintian; Zaidah Zainal Arifin; Zaidah Zainal Ariffin; Shahrul Hisham Zainal Ariffin

2015-01-01

Alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP) and aspartate aminotransferase (AST) activities were studied as bio markers of canine movement. Root resorption was also evaluated in canines subjected to the orthodontic forces. Nineteen subjects randomly received 100 and 150 g force using self-ligating brackets (SLB) either on the right or left site of maxillary arch. Gingival crevicular fluid samples were collected at distal sites of canines for five consecutive weeks. The activities of ALP, TRAP and AST were assayed and measured spectrophotometrically. Canine movement was measured for five consecutive weeks while root resorption was monitored at baseline, week 0 and week 5 using periapical radiographs. In 100 g group, TRAP activity significantly increased in week 3-5 when compared to TRAP baseline activity. However, ALP and AST activities slightly increased. In 150 g group, ALP and TRAP activities slightly increased when compared with their baseline activities. However, AST significantly increased in week 5. Canine movement and root resorption were not significantly different (p<0.05) in both groups. A force of 100 and 150 g slightly increased the bone modeling process and resulted in similar canine movement and root resorption. Therefore, 100 g force could be an optimum force for canine retraction and is preferable (compared with 150 g force) in canine retraction using SLB. (author)

Investigation of persistent Multiplets at the EGS reservoir of Soultz-Sous-Forêts, France

Science.gov (United States)

Lengliné, O.; Cauchie, L.; Schmittbuhl, J.

2017-12-01

During the exploitation of geothermal reservoirs, abundant seismicity is generally observed, especially during phases of hydraulic stimulations. The induced seismicity at the Enhanced Geothermal System of Soultz-Sous-Forêts in France, has been thoroughly studied over the years of exploitation. The mechanism at its origin has been related to both fluid pressure increases during stimulation and aseismic creeping movements. The fluid-induced seismic events often exhibit a high degree of similarity and the mechanism at the origin of these repeated events is thought to be associated with slow slip process where asperities on the rupture zone act several times.To have a better understanding of the mechanisms associated with such events and on the damaged zones involved during the hydraulic stimulations, we investigate the behavior of the multiplets and their persistent nature over several water injection intervals. For this purpose, we analyzed large datasets recorded from a borehole seismic network for several water injection periods (1993, 2000). For each stimulation interval, thousands of events are recorded at depth. We detected the events using a STA/LTA approach and classified them into families of comparable waveforms using an approach based on cross-correlation analysis. Classification of the seismic events is then improved depending on their location within the multiplets. For this purpose, inter-event distances within multiplets are examined and determined from cross-correlation analysis between pairs of events. These distances are then compared to the source dimensions derived from the estimation of the corner frequencies estimation. The multiplets properties (location, events size) are then investigated within and over several hydraulic tests. Hopefully these steps will lead to increase the knowledge on the repetitive nature of these events and the investigation of their persistence will outline the heterogeneities of the structures (regional stress

INTEGRATED GEOLOGIC-ENGINEERING MODEL FOR REEF AND CARBONATE SHOAL RESERVOIRS ASSOCIATED WITH PALEOHIGHS: UPPER JURASSIC SMACKOVER FORMATION, NORTHEASTERN GULF OF MEXICO

Energy Technology Data Exchange (ETDEWEB)

Ernest A. Mancini

2003-09-25

The University of Alabama in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company are undertaking an integrated, interdisciplinary geoscientific and engineering research project. The project is designed to characterize and model reservoir architecture, pore systems and rock-fluid interactions at the pore to field scale in Upper Jurassic Smackover reef and carbonate shoal reservoirs associated with varying degrees of relief on pre-Mesozoic basement paleohighs in the northeastern Gulf of Mexico. The project effort includes the prediction of fluid flow in carbonate reservoirs through reservoir simulation modeling that utilizes geologic reservoir characterization and modeling and the prediction of carbonate reservoir architecture, heterogeneity and quality through seismic imaging. The primary objective of the project is to increase the profitability, producibility and efficiency of recovery of oil from existing and undiscovered Upper Jurassic fields characterized by reef and carbonate shoals associated with pre-Mesozoic basement paleohighs. The principal research effort for Year 3 of the project has been reservoir characterization, 3-D modeling, testing of the geologic-engineering model, and technology transfer. This effort has included six tasks: (1) the study of seismic attributes, (2) petrophysical characterization, (3) data integration, (4) the building of the geologic-engineering model, (5) the testing of the geologic-engineering model and (6) technology transfer. This work was scheduled for completion in Year 3. Progress on the project is as follows: geoscientific reservoir characterization is completed. The architecture, porosity types and heterogeneity of the reef and shoal reservoirs at Appleton and Vocation Fields have been characterized using geological and geophysical data. The study of rock-fluid interactions has been completed. Observations regarding the diagenetic

A Numerical Study of Factors Affecting Fracture-Fluid Cleanup and Produced Gas/Water in Marcellus Shale: Part II

Energy Technology Data Exchange (ETDEWEB)

Seales, Maxian B.; Dilmore, Robert; Ertekin, Turgay; Wang, John Yilin

2017-04-01

Horizontal wells combined with successful multi-stage hydraulic fracture treatments are currently the most established method for effectively stimulating and enabling economic development of gas bearing organic-rich shale formations. Fracture cleanup in the Stimulated Reservoir Volume (SRV) is critical to stimulation effectiveness and long-term well performance. However, fluid cleanup is often hampered by formation damage, and post-fracture well performance frequently falls below expectations. A systematic study of the factors that hinder fracture fluid cleanup in shale formations can help optimize fracture treatments and better quantify long term volumes of produced water and gas. Fracture fluid cleanup is a complex process influenced by multi-phase flow through porous media (relative permeability hysteresis, capillary pressure etc.), reservoir rock and fluid properties, fracture fluid properties, proppant placement, fracture treatment parameters, and subsequent flowback and field operations. Changing SRV and fracture conductivity as production progresses further adds to the complexity of this problem. Numerical simulation is the best, and most practical approach to investigate such a complicated blend of mechanisms, parameters, their interactions, and subsequent impact on fracture fluid cleanup and well deliverability. In this paper, a 3-dimensional, 2-phase, dual-porosity model was used to investigate the impact of multiphase flow, proppant crushing, proppant diagenesis, shut-in time, reservoir rock compaction, gas slippage, and gas desorption on fracture fluid cleanup, and well performance in Marcellus shale. The research findings have shed light on the factors that substantially constrains efficient fracture fluid cleanup in gas shales, and provided guidelines for improved fracture treatment designs and water management.

Numerical investigation of CO2 storage in hydrocarbon field using a geomechanical-fluid coupling model

Directory of Open Access Journals (Sweden)

Guang Li

2016-09-01

Full Text Available Increasing pore pressure due to CO2 injection can lead to stress and strain changes of the reservoir. One of the safely standards for long term CO2 storage is whether stress and strain changes caused by CO2 injection will lead to irreversible mechanical damages of the reservoir and impact the integrity of caprock which could lead to CO2 leakage through previously sealing structures. Leakage from storage will compromise both the storage capacity and the perceived security of the project, therefore, a successful CO2 storage project requires large volumes of CO2 to be injected into storage site in a reliable and secure manner. Yougou hydrocarbon field located in Orods basin was chosen as storage site based on it's stable geological structure and low leakage risks. In this paper, we present a fluid pressure and stress-strain variations analysis for CO2 geological storage based on a geomechanical-fluid coupling model. Using nonlinear elasticity theory to describe the geomechanical part of the model, while using the Darcy's law to describe the fluid flow. Two parts are coupled together using the poroelasticity theory. The objectives of our work were: 1 evaluation of the geomechanical response of the reservoir to different CO2 injection scenarios. 2 assessment of the potential leakage risk of the reservoir caused by CO2 injection.

On the use of double differences in inversion of surface movement measurements

NARCIS (Netherlands)

Fokker, P.A.; Thienen-Visser, K. van

2015-01-01

Surface movement data can be used in data assimilation or inversion exercises to improve the level of knowledge of a compacting reservoir. We have designed, implemented and tested a new algorithm that uses measured optical height differences directly, without having to translate them to heights with

Modeling of Turbidity Variation in Two Reservoirs Connected by a Water Transfer Tunnel in South Korea

Directory of Open Access Journals (Sweden)

Jae Chung Park

2017-06-01

Full Text Available The Andong and Imha reservoirs in South Korea are connected by a water transfer tunnel. The turbidity of the Imha reservoir is much higher than that of the Andong reservoir. Thus, it is necessary to examine the movement of turbidity between the two reservoirs via the water transfer tunnel. The aim of this study was to investigate the effect of the water transfer tunnel on the turbidity behavior of the two connecting reservoirs and to further understand the effect of reservoir turbidity distribution as a function of the selective withdrawal depth. This study applied the CE-QUAL-W2, a water quality and 2-dimensional hydrodynamic model, for simulating the hydrodynamic processes of the two reservoirs. Results indicate that, in the Andong reservoir, the turbidity of the released water with the water transfer tunnel was similar to that without the tunnel. However, in the Imha reservoir, the turbidity of the released water with the water transfer tunnel was lower than that without the tunnel. This can be attributed to the higher capacity of the Andong reservoir, which has double the storage of the Imha reservoir. Withdrawal turbidity in the Imha reservoir was investigated using the water transfer tunnel. This study applied three withdrawal selections as elevation (EL. 141.0 m, 146.5 m, and 152.0 m. The highest withdrawal turbidity resulted in EL. 141.0 m, which indicates that the high turbidity current is located at a vertical depth of about 20–30 m because of the density difference. These results will be helpful for understanding the release and selective withdrawal turbidity behaviors for a water transfer tunnel between two reservoirs.

Compressible fluid flow through rocks of variable permeability

International Nuclear Information System (INIS)

Lin, W.

1977-01-01

The effectiveness of course-grained igneous rocks as shelters for burying radioactive waste can be assessed by determining the rock permeabilities at their in situ pressures and stresses. Analytical and numerical methods were used to solve differential equations of one-dimensional fluid flow through rocks with permeabilities from 10 4 to 1 nD. In these calculations, upstream and downstream reservoir volumes of 5, 50, and 500 cm 3 were used. The optimal size combinations of the two reservoirs were determined for measurements of permeability, stress, strain, acoustic velocity, and electrical conductivity on low-porosity, coarse-grained igneous rocks

Nuclear techniques in industry

International Nuclear Information System (INIS)

Barnette, P.

The long term development and successful utilization of the Tongonan geothermal field for electric power generation is ultimately a function of the response of the reservoir to extensive exploitation. A field drawdown test of several years duration has been planned to test this response. A number of nuclear chemical techniques have been incorporated into this to assist in quantitatively tracing the subsurface movements of both reservoir and reinjected fluids; and to provide an early warning of changes in the physical and chemical properties of the reservoir fluids with respect to natural recharge. The programme will be implemented by Philippine Atomic Energy Commission (PAEC) under contract to Philippine National Oil Company - Energy Development Corporation (PNOC-EDC). (author)

Evaluating changes to reservoir rule curves using historical water-level data

Science.gov (United States)

Mower, Ethan; Miranda, Leandro E.

2013-01-01

Flood control reservoirs are typically managed through rule curves (i.e. target water levels) which control the storage and release timing of flood waters. Changes to rule curves are often contemplated and requested by various user groups and management agencies with no information available about the actual flood risk of such requests. Methods of estimating flood risk in reservoirs are not easily available to those unfamiliar with hydrological models that track water movement through a river basin. We developed a quantile regression model that uses readily available daily water-level data to estimate risk of spilling. Our model provided a relatively simple process for estimating the maximum applicable water level under a specific flood risk for any day of the year. This water level represents an upper-limit umbrella under which water levels can be operated in a variety of ways. Our model allows the visualization of water-level management under a user-specified flood risk and provides a framework for incorporating the effect of a changing environment on water-level management in reservoirs, but is not designed to replace existing hydrological models. The model can improve communication and collaboration among agencies responsible for managing natural resources dependent on reservoir water levels.

Evaluation of natural recharge of Chingshui geothermal reservoir using tritium as a tracer

International Nuclear Information System (INIS)

Cheng, W.; Kuo, T.; Su, C.; Chen, C.; Fan, K.; Liang, H.; Han, Y.

2010-01-01

Naturally existing tritium in groundwater was applied as a tracer to evaluate the natural recharge of the Chingshui geothermal reservoir. The residence time (or, age) of Chingshui geothermal water was first determined with tritium data at 15.2 and 11.3 year using the plug flow and dispersive model, respectively. The annual natural recharge was then estimated by combining the use of the residence time and the fluid-in-place of the Chingshui geothermal reservoir. The natural recharge for Chingshui geothermal reservoir was estimated at 5.0 x 10 5 and 6.7 x 10 5 m 3 year -1 using the plug flow and dispersive model, respectively. Chingshui geothermal water is largely from a fractured zone in the Jentse Member of the Miocene Lushan Formation. The dispersive model more adequately represents the fracture flow system than the simple plug flow model.

Simulation of uncompressible fluid flow through a porous media

International Nuclear Information System (INIS)

Ramirez, A.; Gonzalez, J.L.; Carrillo, F.; Lopez, S.

2009-01-01

Recently, a great interest has been focused for investigations about transport phenomena in disordered systems. One of the most treated topics is fluid flow through anisotropic materials due to the importance in many industrial processes like fluid flow in filters, membranes, walls, oil reservoirs, etc. In this work is described the formulation of a 2D mathematical model to simulate the fluid flow behavior through a porous media (PM) based on the solution of the continuity equation as a function of the Darcy's law for a percolation system; which was reproduced using computational techniques reproduced using a random distribution of the porous media properties (porosity, permeability and saturation). The model displays the filling of a partially saturated porous media with a new injected fluid showing the non-defined advance front and dispersion of fluids phenomena.

MAPPING OF RESERVOIR PROPERTIES AND FACIES THROUGH INTEGRATION OF STATIC AND DYNAMIC DATA

Energy Technology Data Exchange (ETDEWEB)

Albert C. Reynolds; Dean S. Oliver; Fengjun Zhang; Yannong Dong; Jan Arild Skjervheim; Ning Liu