WorldWideScience

Sample records for shelf carbonate reservoirs

  1. Application of Reservoir Characterization and Advanced Technology to Improve Recovery and Economics in a Lower Quality Shallow Shelf Carbonate Reservoir

    Hickman, Scott T.; Justice James L.; Taylor, Archie R.

    1999-01-01

    The Class 2 Project at West Welch was designed to demonstrate the use of advanced technologies to enhance the economics of improved oil recovery (IOR) projects in lower quality Shallow Shelf Carbonate (SSC) reservoirs, resulting in recovery of additional oil that would otherwise be left in the reservoir at project abandonment. Accurate reservoir description is critical to the effective evaluation and efficient design of IOR projects in the heterogeneous SSC reservoirs

  2. Application of Reservoir Characterization and Advanced Technology to Improve Recovery and Economics in a Lower Quality Shallow Shelf Carbonate Reservoir

    Taylor, Archie R.

    1996-01-01

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

  3. CO2 Huff-n-Puff Process in a Light Oil Shallow Shelf Carbonate Reservoir

    Boomer, R.J.; Cole, R.; Kovar, M.; Prieditis, J.; Vogt, J.; Wehner, S.

    1999-02-24

    The application cyclic CO2, often referred to as the CO2 Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO2 Huff-n-Puff process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in capital-intensive miscible projects. Texaco Exploration and Production Inc. and the US Department of Energy have teamed up in a attempt to develop the CO2 Huff-n-Puff process in the Grayburg and San Andres formations which are light oil, shallow shelf carbonate reservoirs that exist throughout the Permian Basin. This cost-shared effort is intended to demonstrate the viability of this underutilized technology in a specific class of domestic reservoir.

  4. Design and Implementation of a CO2 Flood Utilizing Advanced Reservoir Characterization and Horizontal Injection Wells In a Shallow Shelf Carbonate Approaching Waterflood Depletion, Class II; ANNUAL

    Czirr, K.L.; Gaddis, M.P.; Moshell, M.K.

    2002-01-01

    The principle objective of this project is to demonstrate the economic viability and widespread applicability of an innovative reservoir management and carbon dioxide (CO2) flood project development approach for improving CO2 flood project economics in shallow shelf carbonate (SSC) reservoirs

  5. Pennsylvanian carbonate buildups, Paradox basin: Increasing reserves in heterogeneous, shallow-shelf reservoirs

    Montgomery, S.L.; Chidsey, T.C.; Eby, D.E.; Lorenz, D.M.; Culham, W.E.

    1999-01-01

    Productive carbonate buildups of Pennsylvanian age in the southern Paradox basin, Utah, contain up to 200 million bbl remaining oil potentially recoverable by enhanced recovery methods. These buildups comprise over 100 satellite fields to the giant Greater Aneth field, where secondary recovery operations thus far have been concentrated. Several types of satellite buildups exist and produce oil from the Desert Creek zone of the Paradox Formation. Many of the relevant fields have undergone early abandonment; wells in Desert Creek carbonate mounds commonly produce at very high initial rates (>1000 bbl/day) and then suffer precipitous declines. An important new study focused on the detailed characterization of five separate reservoirs has resulted in significant information relevant to their future redevelopment. Completed assessment of Anasazi field suggests that phylloid algal mounds, the major productive buildup type in this area, consist of ten separate lithotypes and can be described in terms of a two-level reservoir system with an underlying high-permeability mound-core interval overlain by a lower permeability but volumetrically larger supramound (mound capping) interval. Reservoir simulations and related performance predictions indicate that CO2 flooding of these reservoirs should have considerable success in recovering remaining oil reserves.Productive carbonate buildups of Pennsylvanian age in the southern Paradox basin, Utah, contain up to 200 million bbl remaining oil potentially recoverable by enhanced recovery methods. These buildups comprise over 100 satellite fields to the giant Greater Aneth field, where secondary recovery operations thus far have been concentrated. Several types of satellite buildups exist and produce oil from the Desert Creek zone of the Paradox Formation. Many of the relevant fields have undergone early abandonment; wells in Desert Creek carbonate mounds commonly produce at very high initial rates (>1000 bbl/day) and then suffer

  6. CO{sub 2} Huff-n-Puff process in a light oil shallow shelf carbonate reservoir. 1994 Annual report

    Wehner, S.C.

    1995-05-01

    It is anticipated that this project will show that the application of the CO{sub 2} Huff-n-Puff process in shallow shelf carbonates can be economically implemented to recover appreciable volumes of light oil. The goals of the project are the development of guidelines for cost-effective selection of candidate reservoirs and wells, along with estimating recovery potential. The selected site for the demonstration project is the Central Vacuum Unit waterflood in Lea County, New Mexico. Work is nearing completion on the reservoir characterization components of the project. The near-term emphasis is to, (1) provide an accurate distribution of original oil-in-place on a waterflood pattern entity level, (2) evaluate past recovery efficiencies, (3) perform parametric simulations, and (4) forecast performance for a site specific field demonstration of the proposed technology. Macro zonation now exists throughout the study area and cross-sections are available. The Oil-Water Contact has been defined. Laboratory capillary pressure data was used to define the initial water saturations within the pay horizon. The reservoir`s porosity distribution has been enhanced with the assistance of geostatistical software. Three-Dimensional kriging created the spatial distributions of porosity at interwell locations. Artificial intelligence software was utilized to relate core permeability to core porosity, which in turn was applied to the 3-D geostatistical porosity gridding. An Equation-of-State has been developed and refined for upcoming compositional simulation exercises. Options for local grid-refinement in the model are under consideration. These tasks will be completed by mid-1995, prior to initiating the field demonstrations in the second budget period.

  7. CO2 Huff-n-Puff process in a light oil shallow shelf carbonate reservoir. Annual report, January 1, 1995--December 31, 1995

    Wehner, S.C.; Boomer, R.J.; Cole, R.; Preiditus, J.; Vogt, J.

    1996-09-01

    The application of cyclic CO{sub 2}, often referred to as the CO{sub 2} Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO{sub 2} H-n-P process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in the capital intensive miscible projects. Texaco Exploration & Production Inc. and the U.S. Department of Energy have teamed up in an attempt to develop the CO{sub 2} Huff-n-Puff process in the Grayburg/San Andres formation; a light oil, shallow shelf carbonate reservoir within the Permian Basin. This cost-shared effort is intended to demonstrate the viability of this underutilized technology in a specific class of domestic reservoir. A significant amount of oil reserves are located in carbonate reservoirs. Specifically, the carbonates deposited in shallow shelf (SSC) environments make up the largest percentage of known reservoirs within the Permian Basin of North America. Many of these known resources have been under waterflooding operations for decades and are at risk of abandonment if crude oil recoveries cannot be economically enhanced. The selected site for this demonstration project is the Central Vacuum Unit waterflood in Lea County, New Mexico.

  8. Application of reservoir characterization and advanced technology to improve recovery and economics in a lower quality shallow shelf carbonate reservoir. End of budget period report, August 3, 1994--December 31, 1996

    Taylor, A.R.; Hinterlong, G.; Watts, G.; Justice, J.; Brown, K.; Hickman, T.S.

    1997-12-01

    The Oxy West Welch project is designed to demonstrate how the use of advanced technology can improve the economics of miscible CO{sub 2} injection projects in a lower quality shallow shelf carbonate reservoir. The research and design phase primarily involves advanced reservoir characterization and accelerating the production response. The demonstration phase will implement the reservoir management plan based on an optimum miscible CO{sub 2} flood as designed in the initial phase. During Budget Period 1, work was completed on the CO{sub 2} stimulation treatments and the hydraulic fracture design. Analysis of the CO{sub 2} stimulation treatment provided a methodology for predicting results. The hydraulic fracture treatment proved up both the fracture design approach a and the use of passive seismic for mapping the fracture wing orientation. Although the 3-D seismic interpretation is still being integrated into the geologic model and interpretation of borehole seismic is still underway, the simulator has been enhanced to the point of giving good waterflood history matches. The simulator-forecasted results for an optimal designed miscible CO{sub 2} flood in the demonstration area gave sufficient economics to justify continuation of the project into Budget Period 2.

  9. Design and Implementation of a CO2 Flood Utilizing Advanced Reservoir Characterization and Horizontal Injection Wells In a Shallow Shelf Carbonate Approaching Waterflood Depletion, Class II

    Wier, Don R. Chimanhusky, John S.; Czirr, Kirk L.; Hallenbeck, Larry; Gerard, Matthew G.; Dollens, Kim B.; Owen, Rex; Gaddis, Maurice; Moshell, M.K.

    2002-11-18

    The purpose of this project was to economically design an optimum carbon dioxide (CO2) flood for a mature waterflood nearing its economic abandonment. The original project utilized advanced reservoir characterization and CO2 horizontal injection wells as the primary methods to redevelop the South Cowden Unit (SCU). The development plans; project implementation and reservoir management techniques were to be transferred to the public domain to assist in preventing premature abandonment of similar fields.

  10. Using Recent Advances in 2D Seismic Technology and Surface Geochemistry to Economically Redevelop a Shallow Shelf Carbonate Reservoir: Vernon Field, Isabella County, M, Class III; ANNUAL

    Wood, James R.; Bornhorst, T.J.; Chittick, S.D.; Harrison, William B.; Tayjor, W. Quinlan

    2001-01-01

    In this project a consortium consisting of Cronus Exploration (Traverse City, MI), Michigan Technological University (Houghton, MI) and Western Michigan University (Kalamazoo, MI) proposed to develop and execute an economical and environmentally sensitive plan for recovery of hydrocarbons from an abandoned shallow-shelf carbonate field that is typical of many fields in the U.S. Midwest. This is a 5-year project that will use surface geochemistry as a tool to reduce risk in locating and producing hydrocarbons in Class II fields. The project will develop new techniques for measuring hydrocarbon gases in the soil horizon to locate new and bypassed oil in the shallow-shelf carbonate environments typified by the Dundee and Trenton Formations of the Michigan Basin (Fisher et. al., 1988). In Phase I of the project, the consortium proposes to re-develop the Vernon Oil field located in Vernon Twp, Isabella County, Michigan and produce both bypassed hydrocarbons from the original field and to locate and produce extensions of the original field

  11. DESIGN AND IMPLEMENTATION OF A CO2 FLOOD UTILIZING ADVANCED RESERVOIR CHARACTERIZATION AND HORIZONTAL INJECTION WELLS IN A SHALLOW SHELF CARBONATE APPROACHING WATERFLOOD DEPLETION

    K.J. Harpole; Ed G. Durrett; Susan Snow; J.S. Bles; Carlon Robertson; C.D. Caldwell; D.J. Harms; R.L. King; B.A. Baldwin; D. Wegener; M. Navarrette

    2002-09-01

    The purpose of this project was to economically design an optimum carbon dioxide (CO{sub 2}) flood for a mature waterflood nearing its economic abandonment. The original project utilized advanced reservoir characterization and CO{sub 2} horizontal injection wells as the primary methods to redevelop the South Cowden Unit (SCU). The development plans; project implementation and reservoir management techniques were to be transferred to the public domain to assist in preventing premature abandonment of similar fields. The Unit was a mature waterflood with water cut exceeding 95%. Oil must be mobilized through the use of a miscible or near-miscible fluid to recover significant additional reserves. Also, because the unit was relatively small, it did not have the benefit of economies of scale inherent in normal larger scale projects. Thus, new and innovative methods were required to reduce investment and operating costs. Two primary methods used to accomplish improved economics were use of reservoir characterization to restrict the flood to the higher quality rock in the unit and use of horizontal injection wells to cut investment and operating costs. The project consisted of two budget phases. Budget Phase I started in June 1994 and ended late June 1996. In this phase Reservoir Analysis, Characterization Tasks and Advanced Technology Definition Tasks were completed. Completion enabled the project to be designed, evaluated, and an Authority for Expenditure (AFE) for project implementation submitted to working interest owners for approval. Budget Phase II consisted of the implementation and execution of the project in the field. Phase II was completed in July 2001. Performance monitoring, during Phase II, by mid 1998 identified the majority of producing wells which under performed their anticipated withdrawal rates. Newly drilled and re-activated wells had lower offtake rates than originally forecasted. As a result of poor offtake, higher reservoir pressure was a concern

  12. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    Raj Kumar; Keith Brown; Hickman, T. Scott; Justice, James J.

    2000-01-01

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

  13. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    Hickman, T. Scott

    2003-01-01

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

  14. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    Hickman, T. Scott; Justice, James J.

    2001-01-01

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

  15. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    T. Scott Hickman; James J. Justice

    2001-06-16

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

  16. Global Carbon Reservoir Oxidative Ratios

    Masiello, C. A.; Gallagher, M. E.; Hockaday, W. C.

    2010-12-01

    Photosynthesis and respiration move carbon and oxygen between the atmosphere and the biosphere at a ratio that is characteristic of the biogeochemical processes involved. This ratio is called the oxidative ratio (OR) of photosynthesis and respiration, and is defined as the ratio of moles of O2 per moles of CO2. This O2/CO2 ratio is a characteristic of biosphere-atmosphere gas fluxes, much like the 13C signature of CO2 transferred between the biosphere and the atmosphere has a characteristic signature. OR values vary on a scale of 0 (CO2) to 2 (CH4), with most ecosystem values clustered between 0.9 and 1.2. Just as 13C can be measured for both carbon fluxes and carbon pools, OR can also be measured for fluxes and pools and can provide information about the processes involved in carbon and oxygen cycling. OR values also provide information about reservoir organic geochemistry because pool OR values are proportional to the oxidation state of carbon (Cox) in the reservoir. OR may prove to be a particularly valuable biogeochemical tracer because of its ability to couple information about ecosystem gas fluxes with ecosystem organic geochemistry. We have developed 3 methods to measure the OR of ecosystem carbon reservoirs and intercalibrated them to assure that they yield accurate, intercomparable data. Using these tools we have built a large enough database of biomass and soil OR values that it is now possible to consider the implications of global patterns in ecosystem OR values. Here we present a map of the natural range in ecosystem OR values and begin to consider its implications. One striking pattern is an apparent offset between soil and biospheric OR values: soil OR values are frequently higher than that of their source biomass. We discuss this trend in the context of soil organic geochemistry and gas fluxes.

  17. Smart waterflooding in carbonate reservoirs

    Zahid, A.

    2012-02-15

    During the last decade, smart waterflooding has been developed into an emerging EOR technology both for carbonate and sandstone reservoirs that does not require toxic or expensive chemicals. Although it is widely accepted that different salinity brines may increase the oil recovery for carbonate reservoirs, understanding of the mechanism of this increase is still developing. To understand this smart waterflooding process, an extensive research has been carried out covering a broad range of disciplines within surface chemistry, thermodynamics of crude oil and brine, as well as their behavior in porous media. The main conclusion of most previous studies was that it is the rock wettability alteration towards more water wetting condition that helps improving the oil recovery. In the first step of this project, we focused on verifying this conclusion. Coreflooding experiments were carried out using Stevens Klint outcrop chalk core plugs with brines without sulfate, as well as brines containing sulfate in different concentrations. The effects of temperature, injection rate, crude oil composition and different sulfate concentrations on the total oil recovery and the recovery rate were investigated. Experimental results clearly indicate improvement of the oil recovery without wettability alteration. At the second step of this project, we studied crude oil/brine interactions under different temperatures, pressures and salinity conditions in order to understand mechanisms behind the high salinity waterflooding. Our results show, in particular that sulfate ions may help decreasing the crude oil viscosity or formation of, seemingly, an emulsion phase between sulfate-enriched brine and oil at high temperature and pressure. Experimental results indicate that crude oils interact differently with the same brine solutions regarding phase behavior and viscosity measurements. This difference is attributed to the difference in composition of the different crude oils. More experiments

  18. Carbon emission from global hydroelectric reservoirs revisited.

    Li, Siyue; Zhang, Quanfa

    2014-12-01

    Substantial greenhouse gas (GHG) emissions from hydropower reservoirs have been of great concerns recently, yet the significant carbon emitters of drawdown area and reservoir downstream (including spillways and turbines as well as river reaches below dams) have not been included in global carbon budget. Here, we revisit GHG emission from hydropower reservoirs by considering reservoir surface area, drawdown zone and reservoir downstream. Our estimates demonstrate around 301.3 Tg carbon dioxide (CO2)/year and 18.7 Tg methane (CH4)/year from global hydroelectric reservoirs, which are much higher than recent observations. The sum of drawdown and downstream emission, which is generally overlooked, represents 42 % CO2 and 67 % CH4 of the total emissions from hydropower reservoirs. Accordingly, the global average emissions from hydropower are estimated to be 92 g CO2/kWh and 5.7 g CH4/kWh. Nonetheless, global hydroelectricity could currently reduce approximate 2,351 Tg CO2eq/year with respect to fuel fossil plant alternative. The new findings show a substantial revision of carbon emission from the global hydropower reservoirs.

  19. Application of sequence stratigraphy to carbonate reservoir prediction, Early Palaeozoic eastern Warburton basin, South Australia

    Xiaowen S.; Stuart, W.J.

    1996-12-31

    The Early Palaeozoic Warburton Basin underlies the gas and oil producing Cooper and Eromanga Basins. Postdepositional tectonism created high potential fracture porosities, complicating the stratigraphy and making reservoir prediction difficult. Sequence stratigraphy integrating core, cuttings, well-log, seismic and biostratigraphic data has recognized a carbonate-dominated to mixed carbonate/siliciclastic supersequence comprising several depositional sequences. Biostratigraphy based on trilobites and conodonts ensures reliable well and seismic correlations across structurally complex areas. Lithofacies interpretation indicates sedimentary environments ranging from carbonate inner shelf, peritidal, shelf edge, deep outer shelf and slope to basin. Log facies show gradually upward shallowing trends or abrupt changes indicating possible sequence boundaries. With essential depositional models and sequence analysis from well data, seismic facies suggest general reflection configurations including parallel-continuous layered patterns indicating uniform neuritic shelf, and mounded structures suggesting carbonate build-ups and pre-existing volcanic relief. Seismic stratigraphy also reveals inclined slope and onlapping margins of a possibly isolated platform geometry. The potential reservoirs are dolomitized carbonates containing oomoldic, vuggy, intercrystalline and fracture porosities in lowstand systems tracts either on carbonate mounds and shelf crests or below shelf edge. The source rock is a deep basinal argillaceous mudstone, and the seal is fine-grained siltstone/shale of the transgressive system tract.

  20. Application of sequence stratigraphy to carbonate reservoir prediction, Early Palaeozoic eastern Warburton basin, South Australia

    Xiaowen S.; Stuart, W.J.

    1996-01-01

    The Early Palaeozoic Warburton Basin underlies the gas and oil producing Cooper and Eromanga Basins. Postdepositional tectonism created high potential fracture porosities, complicating the stratigraphy and making reservoir prediction difficult. Sequence stratigraphy integrating core, cuttings, well-log, seismic and biostratigraphic data has recognized a carbonate-dominated to mixed carbonate/siliciclastic supersequence comprising several depositional sequences. Biostratigraphy based on trilobites and conodonts ensures reliable well and seismic correlations across structurally complex areas. Lithofacies interpretation indicates sedimentary environments ranging from carbonate inner shelf, peritidal, shelf edge, deep outer shelf and slope to basin. Log facies show gradually upward shallowing trends or abrupt changes indicating possible sequence boundaries. With essential depositional models and sequence analysis from well data, seismic facies suggest general reflection configurations including parallel-continuous layered patterns indicating uniform neuritic shelf, and mounded structures suggesting carbonate build-ups and pre-existing volcanic relief. Seismic stratigraphy also reveals inclined slope and onlapping margins of a possibly isolated platform geometry. The potential reservoirs are dolomitized carbonates containing oomoldic, vuggy, intercrystalline and fracture porosities in lowstand systems tracts either on carbonate mounds and shelf crests or below shelf edge. The source rock is a deep basinal argillaceous mudstone, and the seal is fine-grained siltstone/shale of the transgressive system tract.

  1. The exchange of inorganic carbon on the Canadian Beaufort Shelf

    Mol, Jacoba; Thomas, Helmuth; Hu, Xianmin; Myers, Paul G.

    2017-04-01

    The Mackenzie Shelf in the southeastern Beaufort Sea is an area that has experienced large changes in the past several decades as warming, sea-ice loss, and increased river discharge have altered carbon cycling. Upwelling and downwelling events are common on the shelf, caused by strong, fluctuating along-shore winds and resulting cross-shelf Ekman transport. Downwelling carries inorganic carbon and other remineralization products off the shelf and into the deep basin for possible long-term storage in the world oceans. Upwelling carries water high in dissolved inorganic carbon (DIC) and nutrients from the Pacific-origin upper halocline layer (UHL) onto the shelf. Profiles of DIC and total alkalinity (TA) taken in August and September of 2014 are used to investigate the cycling of inorganic carbon on the Mackenzie Shelf. The along-shore and cross-shelf transport of inorganic carbon is quantified using velocity field output from a simulation of the Arctic and Northern Hemisphere Atlantic (ANHA4) configuration of the Nucleus of European Modelling of the Ocean (NEMO) model. A strong upwelling event prior to sampling on the Mackenzie Shelf is analyzed and the resulting influence on the carbonate system, including the saturation state of aragonite and pH levels, is investigated. TA and δ18O are used to examine water mass distributions in the study area and analyze the influence of Pacific Water, Mackenzie River freshwater, and sea-ice melt on carbon dynamics and air-sea fluxes of CO2 in the surface mixed layer. Understanding carbon transfer in this seasonally dynamic environment is key in order to quantify the importance of Arctic shelf regions to the global carbon cycle and to provide a basis for understanding how its role will respond to the aforementioned changes in the regional marine system.

  2. APPLICATION OF RESERVOIR CHARACTERIZATION AND ADVANCED TECHNOLOGY TO IMPROVE RECOVERY AND ECONOMICS IN A LOWER QUALITY SHALLOW SHELF SAN ANDRES RESERVOIR

    Tom Beebe

    2003-05-05

    The OXY-operated Class 2 Project at West Welch is designed to demonstrate how the use of advanced technology can improve the economics of miscible CO{sub 2} injection projects in lower quality Shallow Shelf Carbonate reservoirs. The research and design phase (Budget Period 1) primarily involved advanced reservoir characterization. The current demonstration phase (Budget Period 2) is the implementation of the reservoir management plan for an optimum miscible CO{sub 2} flood design based on the reservoir characterization. Although Budget Period 1 for the Project officially ended 12/31/96, reservoir characterization and simulation work continued during the Budget Period 2. During the seventh annual reporting period (8/3/00-8/2/01) covered by this report, work continued on interpretation of the interwell seismic data to create porosity and permeability profiles which were distributed into the reservoir geostatistically. The initial interwell seismic CO{sub 2} monitor survey was conducted and the acquired data processed and interpretation started. Only limited well work and facility construction were conducted in the project area. The CO{sub 2} injection initiated in October 1997 was continued, although the operator had to modify the operating plan in response to low injection rates, well performance and changes in CO{sub 2} supply. CO{sub 2} injection was focused in a smaller area to increase the reservoir processing rate. By the end of the reporting period three producers had shown sustained oil rate increases and six wells had experienced gas (CO{sub 2}) breakthrough.

  3. Analysis and application of classification methods of complex carbonate reservoirs

    Li, Xiongyan; Qin, Ruibao; Ping, Haitao; Wei, Dan; Liu, Xiaomei

    2018-06-01

    There are abundant carbonate reservoirs from the Cenozoic to Mesozoic era in the Middle East. Due to variation in sedimentary environment and diagenetic process of carbonate reservoirs, several porosity types coexist in carbonate reservoirs. As a result, because of the complex lithologies and pore types as well as the impact of microfractures, the pore structure is very complicated. Therefore, it is difficult to accurately calculate the reservoir parameters. In order to accurately evaluate carbonate reservoirs, based on the pore structure evaluation of carbonate reservoirs, the classification methods of carbonate reservoirs are analyzed based on capillary pressure curves and flow units. Based on the capillary pressure curves, although the carbonate reservoirs can be classified, the relationship between porosity and permeability after classification is not ideal. On the basis of the flow units, the high-precision functional relationship between porosity and permeability after classification can be established. Therefore, the carbonate reservoirs can be quantitatively evaluated based on the classification of flow units. In the dolomite reservoirs, the average absolute error of calculated permeability decreases from 15.13 to 7.44 mD. Similarly, the average absolute error of calculated permeability of limestone reservoirs is reduced from 20.33 to 7.37 mD. Only by accurately characterizing pore structures and classifying reservoir types, reservoir parameters could be calculated accurately. Therefore, characterizing pore structures and classifying reservoir types are very important to accurate evaluation of complex carbonate reservoirs in the Middle East.

  4. Smart Waterflooding in Carbonate Reservoirs

    Zahid, Adeel

    brine solutions regarding phase behavior and viscosity measurements. This difference is attributed to the difference in composition of the different crude oils. More experiments are carried out in order to understand mechanisms of the crude oil viscosity reduction and emulsion formation. We observed...... with and without aging. The total oil recovery, recovery rate and interaction mechanisms of ions with rock were studied for different injected fluids under different temperatures and wettability conditions. Experimental results demonstrate that the oil recovery mechanism under high salinity seawater flooding...... phase could be the possible reasons for the observed increase in oil recovery with sulfate ions at high temperature in chalk reservoirs, besides the mechanism of the rock wettability alteration. * Crude oil/brine interaction study suggests that viscosity reduction for crude oil in contact with brine...

  5. Advances in carbonate exploration and reservoir analysis

    Garland, J.; Neilson, J.; Laubach, S.E.; Whidden, Katherine J.

    2012-01-01

    The development of innovative techniques and concepts, and the emergence of new plays in carbonate rocks are creating a resurgence of oil and gas discoveries worldwide. The maturity of a basin and the application of exploration concepts have a fundamental influence on exploration strategies. Exploration success often occurs in underexplored basins by applying existing established geological concepts. This approach is commonly undertaken when new basins ‘open up’ owing to previous political upheavals. The strategy of using new techniques in a proven mature area is particularly appropriate when dealing with unconventional resources (heavy oil, bitumen, stranded gas), while the application of new play concepts (such as lacustrine carbonates) to new areas (i.e. ultra-deep South Atlantic basins) epitomizes frontier exploration. Many low-matrix-porosity hydrocarbon reservoirs are productive because permeability is controlled by fractures and faults. Understanding basic fracture properties is critical in reducing geological risk and therefore reducing well costs and increasing well recovery. The advent of resource plays in carbonate rocks, and the long-standing recognition of naturally fractured carbonate reservoirs means that new fracture and fault analysis and prediction techniques and concepts are essential.

  6. Mineralogy of the carbonate sediments - western continental shelf of India

    Nair, R.R.; Hashimi, N.H.

    An X-ray diffraction study of forty-six sediment samples and three oolitic limestone samples from the western continental shelf of India shows that aragonite is the dominant carbonate mineral (99% maximum), followed by low-magnesium calcite (77...

  7. Reservoirs as hotspots of fluvial carbon cycling in peatland catchments.

    Stimson, A G; Allott, T E H; Boult, S; Evans, M G

    2017-02-15

    Inland water bodies are recognised as dynamic sites of carbon processing, and lakes and reservoirs draining peatland soils are particularly important, due to the potential for high carbon inputs combined with long water residence times. A carbon budget is presented here for a water supply reservoir (catchment area~9km 2 ) draining an area of heavily eroded upland peat in the South Pennines, UK. It encompasses a two year dataset and quantifies reservoir dissolved organic carbon (DOC), particulate organic carbon (POC) and aqueous carbon dioxide (CO 2 (aq)) inputs and outputs. The budget shows the reservoir to be a hotspot of fluvial carbon cycling, as with high levels of POC influx it acts as a net sink of fluvial carbon and has the potential for significant gaseous carbon export. The reservoir alternates between acting as a producer and consumer of DOC (a pattern linked to rainfall and temperature) which provides evidence for transformations between different carbon species. In particular, the budget data accompanied by 14 C (radiocarbon) analyses provide evidence that POC-DOC transformations are a key process, occurring at rates which could represent at least ~10% of the fluvial carbon sink. To enable informed catchment management further research is needed to produce carbon cycle models more applicable to these environments, and on the implications of high POC levels for DOC composition. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Larger foraminifera distribution on a mesotrophic carbonate shelf in SW Sulawesi (Indonesia)

    Renema, W.; Troelstra, S.R.

    2001-01-01

    Larger symbiont bearing foraminifera typically live in shallow tropical seas. In this study the fauna composition of patch reefs scattered over the Spermonde Shelf (SW Sulawesi, Indonesia), a mesotrophic carbonate shelf, is examined. The foraminiferal fauna of the Spermonde Shelf is characterised by

  9. Diagenesis and reservoir quality evolution of palaeocene deep-water, marine sandstones, the Shetland-Faroes Basin, British continental shelf

    Mansurbeg, H. [Department of Earth Sciences, Uppsala University, Villavaegen 16, SE 752 36 Uppsala (Sweden); Morad, S. [Department of Earth Sciences, Uppsala University, Villavaegen 16, SE 752 36 Uppsala (Sweden); Department of Petroleum Geosciences, The Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Salem, A. [Faculty of Education at Kafr El-Sheikh, Tanta University, Kafr El-Sheikh (Egypt); Marfil, R.; Caja, M.A. [Departmento Petrologia y Geoquimica, Facultad de Geologia, UCM, 28040 Madrid (Spain); El-ghali, M.A.K. (Geology Department, Al-Fateh University, P.O. Box 13696, Libya); Nystuen, J.P. [Department of Geosciences, University of Oslo, P.O. Box 1047 Blindern, NO-0316 Oslo (Norway); Amorosi, A. [Department of Earth Sciences, University of Bologna, Via Zamboni 67, 40127 Bologna (Italy); Garcia, D. [Centre SPIN, Department GENERIC, Ecole Nationale Superieure des Mines de Saint Etienne 158, Cours Fauriel 42023, Saint-Etienne (France); La Iglesia, A. [Instituto de Geologia Economica (CSIC-UCM), Facultad de Geologia, UCM, 28040 Madrid (Spain)

    2008-06-15

    The Palaeocene, deep-water marine sandstones recovered from six wells in the Shetland-Faroes Basin represent lowstand, transgressive and highstand systems tract turbiditic sediments. Mineralogic, petrographic, and geochemical analyses of these siliciclastics are used to decipher and discuss the diagenetic alterations and subsequent reservoir quality evolution. The Middle-Upper Palaeocene sandstones (subarkoses to arkoses) from the Shetland-Faroes Basin, British continental shelf are submarine turbiditic deposits that are cemented predominantly by carbonates, quartz and clay minerals. Carbonate cements (intergranular and grain replacive calcite, siderite, ferroan dolomite and ankerite) are of eogenetic and mesogenetic origins. The eogenetic alterations have been mediated by marine, meteoric and mixed marine/meteoric porewaters and resulted mainly in the precipitation of calcite ({delta}{sup 18}O{sub V-PDB}=-10.9 permille and -3.8 permille), trace amounts of non-ferroan dolomite, siderite ({delta}{sup 18}O{sub V-PDB}=-14.4 permille to -0.6 permille), as well as smectite and kaolinite in the lowstand systems tract (LST) and highstand systems tract (HST) turbiditic sandstone below the sequence boundary. Minor eogenetic siderite has precipitated between expanded and kaolinitized micas, primarily biotite. The mesogenetic alterations are interpreted to have been mediated by evolved marine porewaters and resulted in the precipitation of calcite ({delta}{sup 18}O{sub V-PDB}=-12.9 permille to -7.8 permille) and Fe-dolomite/ankerite ({delta}{sup 18}O{sub V-PDB}=-12.1 permille to -6.3 permille) at temperatures of 50-140 and 60-140 C, respectively. Quartz overgrowths and outgrowth, which post- and pre-date the mesogenetic carbonate cements is more common in the LST and TST of distal turbiditic sandstone. Discrete quartz cement, which is closely associated with illite and chlorite, is the final diagenetic phase. The clay minerals include intergranular and grain replacive

  10. Low Impedance Carbon Adhesive Electrodes with Long Shelf Life.

    Posada-Quintero, Hugo F; Reyes, Bersaín A; Burnham, Ken; Pennace, John; Chon, Ki H

    2015-10-01

    A novel electrocardiogram (ECG) electrode film is developed by mixing carbon black powder and a quaternary salt with a visco-elastic polymeric adhesive. Unlike traditional wet gel-based electrodes, carbon/salt/adhesive (CSA) electrodes should theoretically have an infinite shelf life as they do not dehydrate even after a prolonged period of storage. The CSA electrodes are electrically activated for use through the process of electrophoresis. Specifically, the activation procedure involves sending a high voltage and current through the electrode, which results in significant reduction of impedance so that high fidelity ECG signals can be obtained. Using the activation procedure, the ideal concentration of carbon black powder in the mixture with the adhesive was examined. It was determined that the optimum concentration of carbon black which minimized post-activation impedance was 10%. Once the optimal carbon black powder concentration was determined, extensive signal analysis was performed to compare the performance of the CSA electrodes to the standard silver-silver chloride (Ag/AgCl) electrodes. As a part of data analysis, electrode-skin contact impedance of the CSA was measured and compared to the standard Ag/AgCl electrodes; we found consistently lower impedance for CSA electrodes. For quantitative data analysis, we simultaneously collected ECG data with CSA and Ag/AgCl electrodes from 17 healthy subjects. Heart rate variability (HRV) indices and ECG morphological waveforms were calculated to compare CSA and Ag/AgCl electrodes. Non-significant differences for most of the HRV indices between CSA and Ag/AgCl electrodes were found. Of the morphological waveform metrics consisting of R-wave peak amplitude, ST-segment elevation and QT interval, only the first index was found to be significantly different between the two media. The response of CSA electrodes to motion artifacts was also tested, and we found in general no difference in the quality of the ECG signal

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

    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)

  12. Carbonate reservoir characterization with lithofacies clustering and porosity prediction

    Al Moqbel, Abdulrahman; Wang, Yanghua

    2011-01-01

    One of the objectives in reservoir characterization is to quantitatively or semi-quantitatively map the spatial distribution of its heterogeneity and related properties. With the availability of 3D seismic data, artificial neural networks are capable of discovering the nonlinear relationship between seismic attributes and reservoir parameters. For a target carbonate reservoir, we adopt a two-stage approach to conduct characterization. First, we use an unsupervised neural network, the self-organizing map method, to classify the reservoir lithofacies. Then we apply a supervised neural network, the back-propagation algorithm, to quantitatively predict the porosity of the carbonate reservoir. Based on porosity maps at different time levels, we interpret the target reservoir vertically related to three depositional phases corresponding to, respectively, a lowstand system tract before sea water immersion, a highstand system tract when water covers organic deposits and a transition zone for the sea level falling. The highstand system is the most prospective zone, given the organic content deposited during this stage. The transition zone is also another prospective feature in the carbonate depositional system due to local build-ups

  13. Integration of rock typing methods for carbonate reservoir characterization

    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)

  14. NW European shelf under climate warming: implications for open ocean – shelf exchange, primary production, and carbon absorption

    M. Gröger

    2013-06-01

    Full Text Available Shelves have been estimated to account for more than one-fifth of the global marine primary production. It has been also conjectured that shelves strongly influence the oceanic absorption of anthropogenic CO2 (carbon shelf pump. Owing to their coarse resolution, currently applied global climate models are inappropriate to investigate the impact of climate change on shelves and regional models do not account for the complex interaction with the adjacent open ocean. In this study, a global ocean general circulation model and biogeochemistry model were set up with a distorted grid providing a maximal resolution for the NW European shelf and the adjacent northeast Atlantic. Using model climate projections we found that already a~moderate warming of about 2.0 K of the sea surface is linked with a reduction by ~ 30% of the biological production on the NW European shelf. If we consider the decline of anthropogenic riverine eutrophication since the 1990s, the reduction of biological production amounts is even larger. The relative decline of NW European shelf productivity is twice as strong as the decline in the open ocean (~ 15%. The underlying mechanism is a spatially well confined stratification feedback along the continental shelf break. This feedback reduces the nutrient supply from the deep Atlantic to about 50%. In turn, the reduced productivity draws down CO2 absorption in the North Sea by ~ 34% at the end of the 21st century compared to the end of the 20th century implying a strong weakening of shelf carbon pumping. Sensitivity experiments with diagnostic tracers indicate that not more than 20% of the carbon absorbed in the North Sea contributes to the long-term carbon uptake of the world ocean. The rest remains within the ocean's mixed layer where it is exposed to the atmosphere. The predicted decline in biological productivity, and decrease of phytoplankton concentration (in the North Sea by averaged 25% due to reduced nutrient imports from

  15. Inorganic carbon fluxes on the Mackenzie Shelf of the Beaufort Sea

    Mol, Jacoba; Thomas, Helmuth; Myers, Paul G.; Hu, Xianmin; Mucci, Alfonso

    2018-02-01

    The Mackenzie Shelf in the southeastern Beaufort Sea is a region that has experienced large changes in the past several decades as warming, sea-ice loss, and increased river discharge have altered carbon cycling. Upwelling and downwelling events are common on the shelf, caused by strong, fluctuating along-shore winds, resulting in cross-shelf Ekman transport, and an alternating estuarine and anti-estuarine circulation. Downwelling carries dissolved inorganic carbon (DIC) and other remineralization products off the shelf and into the deep basin for possible long-term storage in the world's oceans. Upwelling carries DIC and nutrient-rich waters from the Pacific-origin upper halocline layer (UHL) onto the shelf. Profiles of DIC and total alkalinity (TA) taken in August and September of 2014 are used to investigate the cycling of carbon on the Mackenzie Shelf. The along-shore transport of water and the cross-shelf transport of DIC are quantified using velocity field output from a simulation of the Arctic and Northern Hemisphere Atlantic (ANHA4) configuration of the Nucleus of European Modelling of the Ocean (NEMO) framework. A strong upwelling event prior to sampling on the Mackenzie Shelf took place, bringing CO2-rich (elevated pCO2) water from the UHL onto the shelf bottom. The maximum on-shelf DIC flux was estimated at 16.9×103 mol C d-1 m-2 during the event. The maximum on-shelf transport of DIC through the upwelling event was found to be 65±15×10-3 Tg C d-1. TA and the oxygen isotope ratio of water (δ18O-H2O) are used to examine water-mass distributions in the study area and to investigate the influence of Pacific Water, Mackenzie River freshwater, and sea-ice melt on carbon dynamics and air-sea fluxes of carbon dioxide (CO2) in the surface mixed layer. Understanding carbon transfer in this seasonally dynamic environment is key to quantify the importance of Arctic shelf regions to the global carbon cycle and provide a basis for understanding how it will

  16. Inorganic carbon fluxes on the Mackenzie Shelf of the Beaufort Sea

    J. Mol

    2018-02-01

    Full Text Available The Mackenzie Shelf in the southeastern Beaufort Sea is a region that has experienced large changes in the past several decades as warming, sea-ice loss, and increased river discharge have altered carbon cycling. Upwelling and downwelling events are common on the shelf, caused by strong, fluctuating along-shore winds, resulting in cross-shelf Ekman transport, and an alternating estuarine and anti-estuarine circulation. Downwelling carries dissolved inorganic carbon (DIC and other remineralization products off the shelf and into the deep basin for possible long-term storage in the world's oceans. Upwelling carries DIC and nutrient-rich waters from the Pacific-origin upper halocline layer (UHL onto the shelf. Profiles of DIC and total alkalinity (TA taken in August and September of 2014 are used to investigate the cycling of carbon on the Mackenzie Shelf. The along-shore transport of water and the cross-shelf transport of DIC are quantified using velocity field output from a simulation of the Arctic and Northern Hemisphere Atlantic (ANHA4 configuration of the Nucleus of European Modelling of the Ocean (NEMO framework. A strong upwelling event prior to sampling on the Mackenzie Shelf took place, bringing CO2-rich (elevated pCO2 water from the UHL onto the shelf bottom. The maximum on-shelf DIC flux was estimated at 16.9×103 mol C d−1 m−2 during the event. The maximum on-shelf transport of DIC through the upwelling event was found to be 65±15×10−3 Tg C d−1. TA and the oxygen isotope ratio of water (δ18O-H2O are used to examine water-mass distributions in the study area and to investigate the influence of Pacific Water, Mackenzie River freshwater, and sea-ice melt on carbon dynamics and air–sea fluxes of carbon dioxide (CO2 in the surface mixed layer. Understanding carbon transfer in this seasonally dynamic environment is key to quantify the importance of Arctic shelf regions to the global carbon cycle and provide a basis

  17. Macronutrient and carbon supply, uptake and cycling across the Antarctic Peninsula shelf during summer.

    Henley, Sian F; Jones, Elizabeth M; Venables, Hugh J; Meredith, Michael P; Firing, Yvonne L; Dittrich, Ribanna; Heiser, Sabrina; Stefels, Jacqueline; Dougans, Julie

    2018-06-28

    The West Antarctic Peninsula shelf is a region of high seasonal primary production which supports a large and productive food web, where macronutrients and inorganic carbon are sourced primarily from intrusions of warm saline Circumpolar Deep Water. We examined the cross-shelf modification of this water mass during mid-summer 2015 to understand the supply of nutrients and carbon to the productive surface ocean, and their subsequent uptake and cycling. We show that nitrate, phosphate, silicic acid and inorganic carbon are progressively enriched in subsurface waters across the shelf, contrary to cross-shelf reductions in heat, salinity and density. We use nutrient stoichiometric and isotopic approaches to invoke remineralization of organic matter, including nitrification below the euphotic surface layer, and dissolution of biogenic silica in deeper waters and potentially shelf sediment porewaters, as the primary drivers of cross-shelf enrichments. Regenerated nitrate and phosphate account for a significant proportion of the total pools of these nutrients in the upper ocean, with implications for the seasonal carbon sink. Understanding nutrient and carbon dynamics in this region now will inform predictions of future biogeochemical changes in the context of substantial variability and ongoing changes in the physical environment.This article is part of the theme issue 'The marine system of the West Antarctic Peninsula: status and strategy for progress in a region of rapid change'. © 2018 The Authors.

  18. Evaluating the Influence of Pore Architecture and Initial Saturation on Wettability and Relative Permeability in Heterogeneous, Shallow-Shelf Carbonates

    Byrnes, Alan P.; Bhattacharya, Saibal; Victorine, John; Stalder, Ken

    2007-09-30

    carbonate reservoirs of widely varying moldic pore systems that represent the major of reservoirs in Kansas and are important nationally and worldwide. A goal of the project is to measure wettability, using representative oils from Kansas fields, on a wide range of moldic-porosity lithofacies that are representative of Kansas and midcontinent shallow-shelf carbonate reservoirs. This investigation will discern the relative influence of wetting and pore architecture. In the midcontinent, reservoir water saturations are frequently greater than 'irreducible' because many reservoirs are largely in the capillary transition zone. This can change the imbibition oil-water relative permeability relations. Ignoring wettability and transition-zone relative permeabilities in reservoir modeling can lead to over- and under-prediction of oil recovery and recovery rates, and less effective improved recovery management. A goal of this project is to measure drainage and imbibition oil-water relative permeabilities for a large representative range of lithofacies at differ ent initial water saturations to obtain relations that can be applied everywhere in the reservoir. The practical importance of these relative permeability and wettability models will be demonstrated by using reservoir simulation studies on theoretical/generic and actual reservoir architectures. The project further seeks to evaluate how input of these new models affects reservoir simulation results at varying scales. A principal goal is to obtain data that will allow us to create models that will show how to accurately simulate flow in the shallow-structure, complex carbonate reservoirs that lie in the transition zone. Tasks involved to meet the project objectives include collection and consolidation of available data into a publicly accessible relational digital database and collection of oil and rock samples from carbonate fields around the state (Task 1). Basic properties of these rocks and oils will be measured

  19. Geochemistry of Precambrian carbonates - 3-shelf seas and non-marine environments of the Archean

    Veizer, Jan; Clayton, R. N.; Hinton, R. W.; Von Brunn, Victor; Mason, T. R.

    1990-01-01

    Samples from the Pangola and Ventersdorp Supergroups (Kaapvaal Craton, South Africa) and from the Fortescue and Hamersley Groups (Pilbara Block, Australia) were analyzed, using XRF, AAS, and isotope-analysis techniques to investigate the mineralogical, chemical, and isotopic features of these representatives of contemporary shelf carbonates (Pangola and Hamersley samples) and nonmarine carbonates (the Ventersdorp and Fortescue samples). Results show that, mineralogically, the shelf carbonates are almost exclusively dolostones, while the lacustrine facies are predominantly limestones. Geological, trace-element, and oxygen-isotope results of the shelf carbonates suggest that their original mineralogy may have been aragonite, and that the Pangola dolostones may represent a direct dolomitization product of this precursor. By contrast, the stabilization of the Hamersley carbonates may have involved an additional step of transformation of a metastable precursor into limestone.

  20. Matrix acidification in carbonate reservoirs; Acidificacoes matriciais em reservatorios carbonaticos

    Martins, Marcio de Oliveira [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)

    2012-07-01

    Carbonate reservoirs are characterized by great diversity of its properties, including permeability and porosity. When submitted to matrix acidification, if no effort is employed, acid will tend to consume carbonates where permeability and porosity are higher, further increasing conductivity of these sites and also increasing permeability and porosity contrast existing before acid effects on formation. That would give limited production as result of small effective producer zone extent, with probable underutilization of potential reservoirs productivity. To overcome this effect and to achieve greater coverage of treatments, divergence techniques should be applied, including associations of them. This paper presents divergence techniques performed in matrix acidification of Campos and Espirito Santo basins wells, which represent great structural diversity and, as consequence, a significant range of situations. Formations tests results are analyzed to verify diversion systems effectiveness, and how they contribute to the growth of productive potential. (author)

  1. Carbon mineralization in Laptev and East Siberian sea shelf and slope sediment

    V. Brüchert

    2018-01-01

    Full Text Available The Siberian Arctic Sea shelf and slope is a key region for the degradation of terrestrial organic material transported from the organic-carbon-rich permafrost regions of Siberia. We report on sediment carbon mineralization rates based on O2 microelectrode profiling; intact sediment core incubations; 35S-sulfate tracer experiments; pore-water dissolved inorganic carbon (DIC; δ13CDIC; and iron, manganese, and ammonium concentrations from 20 shelf and slope stations. This data set provides a spatial overview of sediment carbon mineralization rates and pathways over large parts of the outer Laptev and East Siberian Arctic shelf and slope and allows us to assess degradation rates and efficiency of carbon burial in these sediments. Rates of oxygen uptake and iron and manganese reduction were comparable to temperate shelf and slope environments, but bacterial sulfate reduction rates were comparatively low. In the topmost 50 cm of sediment, aerobic carbon mineralization dominated degradation and comprised on average 84 % of the depth-integrated carbon mineralization. Oxygen uptake rates and anaerobic carbon mineralization rates were higher in the eastern East Siberian Sea shelf compared to the Laptev Sea shelf. DIC ∕ NH4+ ratios in pore waters and the stable carbon isotope composition of remineralized DIC indicated that the degraded organic matter on the Siberian shelf and slope was a mixture of marine and terrestrial organic matter. Based on dual end-member calculations, the terrestrial organic carbon contribution varied between 32 and 36 %, with a higher contribution in the Laptev Sea than in the East Siberian Sea. Extrapolation of the measured degradation rates using isotope end-member apportionment over the outer shelf of the Laptev and East Siberian seas suggests that about 16 Tg C yr−1 is respired in the outer shelf seafloor sediment. Of the organic matter buried below the oxygen penetration depth, between 0.6 and 1.3

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

    Stephen C. Ruppel

    2005-02-01

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

  3. Petroleum Characterisation and Reservoir Dynamics - The Froey Field and the Rind Discovery, Norwegian Continental Shelf

    Bhullar, Abid G.

    1999-07-01

    The objective of this thesis is to apply the fundamental principles of petroleum geochemistry integrated with petroleum/reservoir engineering and geological concepts to the dynamics and characterisation of petroleum reservoirs. The study is based on 600 core samples and 9 DST oils from 11 wells in the Froey Field and the Rind Discovery. The work is presented in five papers. Paper 1 is a detailed characterisation of the reservoirs using a petroleum geochemical approach. Paper 2 describes the application of a single reservoir geochemical screening technique to exploration, appraisal and production geology and reservoir/petroleum engineering. Paper 3 compares the Iatroscan TLC-FID screening technique and the extraction efficiency of micro-extraction used in this work with the well-established Rock-Eval geochemical screening method and with the Soxtec extraction method. Paper 4 refines the migration and filling models of Paper 1, and Paper 5 presents a comparison of models of petroleum generation, migration and accumulation based on geochemical data with 1D burial history, a ''pseudo well'' based on actual well data and regional seismic analysis representing the hydrocarbon generative basin conditions.

  4. Carbon Monoxide Modified Atmosphere Packaging Beef Shelf Life Studies

    Rini Ariani Basyamfar

    2014-02-01

    Full Text Available The combination of O2, CO2, and low concentrations of CO in CO-MAP has repeatedly been shown to increase the shelf-life of red meat products. Concentrations of CO2 of 30% has been shown to slow microbial growth while O2 preserves the natural color of red meat. The addition of low concentrations of CO (<0.4% preserves the color stability of the meat while allowing for lower levels of O2 which reduces the oxidative spoilage of the product. Shelf-life extension of 5 to 10 days above traditional MAP has been seen with CO-MAP technologies. The addition of active/smart films such as antimicrobial films and/or the combination of irradiation further extends the shelf-life of red meat. Undetectable levels of E. coli at storage temperatures as high as 10oC at 28 days have been shown with CO-MAP and irradiation.

  5. Carbon Sequestration in Unconventional Reservoirs: Geophysical, Geochemical and Geomechanical Considerations

    Zakharova, Natalia V.

    In the face of the environmental challenges presented by the acceleration of global warming, carbon capture and storage, also called carbon sequestration, may provide a vital option to reduce anthropogenic carbon dioxide emissions, while meeting the world's energy demands. To operate on a global scale, carbon sequestration would require thousands of geologic repositories that could accommodate billions of tons of carbon dioxide per year. In order to reach such capacity, various types of geologic reservoirs should be considered, including unconventional reservoirs such as volcanic rocks, fractured formations, and moderate-permeability aquifers. Unconventional reservoirs, however, are characterized by complex pore structure, high heterogeneity, and intricate feedbacks between physical, chemical and mechanical processes, and their capacity to securely store carbon emissions needs to be confirmed. In this dissertation, I present my contribution toward the understanding of geophysical, geochemical, hydraulic, and geomechanical properties of continental basalts and fractured sedimentary formations in the context of their carbon storage capacity. The data come from two characterization projects, in the Columbia River Flood Basalt in Washington and the Newark Rift Basin in New York, funded by the U.S. Department of Energy through Big Sky Carbon Sequestration Partnerships and TriCarb Consortium for Carbon Sequestration. My work focuses on in situ analysis using borehole geophysical measurements that allow for detailed characterization of formation properties on the reservoir scale and under nearly unaltered subsurface conditions. The immobilization of injected CO2 by mineralization in basaltic rocks offers a critical advantage over sedimentary reservoirs for long-term CO2 storage. Continental flood basalts, such as the Columbia River Basalt Group, possess a suitable structure for CO2 storage, with extensive reservoirs in the interflow zones separated by massive impermeable

  6. Carbon Sequestration in a Large Hydroelectric Reservoir: An Integrative Seismic Approach

    Mendonca, R.; Kosten, S.; Sobek, S.; Cole, J.J.; Bastos, A.C.; Albuquerque, A.L.; Cardoso, S.J.; Roland, F.

    2014-01-01

    Artificial reservoirs likely accumulate more carbon than natural lakes due to their unusually high sedimentation rates. Nevertheless, the actual magnitude of carbon accumulating in reservoirs is poorly known due to a lack of whole-system studies of carbon burial. We determined the organic carbon

  7. Thermochemical sulphate reduction can improve carbonate petroleum reservoir quality

    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.

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

    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.

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

    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

  10. Lithology-dependent In Situ Stress in Heterogeneous Carbonate Reservoirs

    Pham, C. N.; Chang, C.

    2017-12-01

    Characterization of in situ stress state for various geomechanical aspects in petroleum development may be particularly difficult in carbonate reservoirs in which rock properties are generally heterogeneous. We demonstrate that the variation of in situ stress in highly heterogeneous carbonate reservoirs is closely related to the heterogeneity in rock mechanical property. The carbonate reservoir studied consists of numerous sequential layers gently folded, exhibiting wide ranges of porosity (0.01 - 0.29) and Young's modulus (25 - 85 GPa) depending on lithology. Wellbore breakouts and drilling-induced tensile fractures (DITFs) observed in the image logs obtained from several wells indicate that the in situ state of stress orientation changes dramatically with depth and location. Even in a wellbore, the azimuth of the maximum horizontal stress changes by as much as 60° within a depth interval of 500 m. This dramatic change in stress orientation is inferred to be due to the contrast in elastic properties between different rock layers which are bent by folding in the reservoir. The horizontal principal stress magnitudes are constrained by back-calculating stress conditions necessary to induce the observed wellbore failures using breakout width and the presence of DITFs. The horizontal stresses vary widely, which cannot be represented by a constant stress gradient with depth. The horizontal principal stress gradient increases with Young's modulus of layer monotonically, indicating that a stiffer layer conveys a higher horizontal stress. This phenomenon can be simulated using a numerical modelling, in which the horizontal stress magnitudes depend on stiffness of individual layers although the applied far-field stress conditions are constant. The numerical results also suggest that the stress concentration at the wellbore wall is essentially higher in a stiffer layer, promoting the possibility of wellbore breakout formation. These results are in agreement with our

  11. Experimental and numerical modeling of sulfur plugging in carbonate reservoirs

    Abou-Kassem, J.H. [Chemical and Petroleum Engineering Department, UAE University, PO Box 17555, Al-Ain (United Arab Emirates)

    2000-05-01

    Sour gas, mainly in the form of hydrogen sulfide, is produced in large amounts from many oil and gas reservoirs in the United Arab Emirates. In addition to creating problems in production lines, the precipitation of elemental sulfur in vicinity of the wellbore is often reported to cause wellbore damage. While there have been several studies performed on the role of solid deposition in gas reservoirs, the role of sulfur deposition in oil reservoirs has not been investigated. This paper presents experimental results along with a comprehensive wellbore model that predicts sulfur precipitation as well as plugging. Two separate sets of experiments, one for a gas phase system and another for a crude oil system, were conducted to investigate the deposition of elemental sulfur in (linear) carbonate cores. The gas flow tests were conducted with elemental sulfur being carried with nitrogen through limestone cores. Changes in gas flow rate were monitored while the injection pressure was held constant. A series of experiments generated valuable data for plugging with elemental sulfur. X-ray diffraction tests provided evidence of sulfur deposition along the cores. The oil flow tests were carried out to observe sulfur precipitation and plugging in a carbonate core. The crude oil was de-asphalted before conducting these tests in order to isolate the effect of asphaltene plugging. Significant plugging was observed and was found to be dependent on flow rate and initial sulfur concentration. This information was used in a phenomenological model that was incorporated in the wellbore numerical model. The data for the numerical model were obtained from both test tube and oil flow experiments. By using a phenomenological model, the wellbore plugging was modeled with an excellent match (with experimental results)

  12. Subsurface Permian reef complexes of southern Tunisia: Shelf carbonate setting and paleogeographic implications

    Zaafouri, Adel; Haddad, Sofiene; Mannaî-Tayech, Beya

    2017-05-01

    2-D seismic reflection sections, borehole data as well as published and unpublished data have been investigated to reconstruct the paleogeography of southern Tunisia during Middle to Late Permian times. Paleogeographical reconstruction based on the integration of petroleum well data and 2-D seismic facies interpretation shows three main depositional areas with very contrasting sedimentary pile. These are 1) a subsiding basin; 2) an outer shelf carbonate, and 3) an inner shelf carbonate. Based on typical electric responses of reef buildups to seismic wave, we shall urge that during Middle Permian times, the outer carbonate shelf was subject of reef barrier development. Lithology evidences from core samples show that reef framework correspond mainly to fossiliferous limestone and dolomite. The WNW-ESE recognized reef barrier led between latitudes 33° 10‧ 00″N and 33° 20‧ 00″N. The Tebaga of Medenine outcrop constitutes the northern-edge of this barrier. Westward it may be extended to Bir Soltane area whereas its extension eastward is still to be determined. Biogenic buildups took place preferentially over faulted Carboniferous and lower Paleozoic paleohighs resulting likely from the Hercynian orogeny. The subsiding basin is located north of Tebaga of Medenine outcrop where Upper Permian sedimentary sequence is made entirely of 4000 m deep marine green silty shale facies. These are ascribed to unorganized and chaotic reflectors. Inner carbonate shelf facies succession corresponds to a typical interbedding of shallow marine carbonate deposits, shale, dolomite, and anhydrite inducing parallel-layered of strong amplitude and good continuity reflectors. Also within the inner carbonate shelf patch reef or reef pinnacles have been identified based on their seismic signature particularly their low vertical development as compared to reef complexes. Southward, towards Sidi Toui area, the Upper Permian depositional sequence thins out and bears witness of land

  13. Carbonated fermented dairy drink - effect on quality and shelf life.

    Ravindra, Menon Rekha; Rao, K Jayaraj; Nath, B Surendra; Ram, Chand

    2014-11-01

    Processing conditions were standardized for a carbonated sweetened fermented dairy beverage. The optimum level of carbonation for the beverage filled in 200 ml glass bottles was found to be at 50 psi pressure for 30 seconds. The beverage samples were stored under refrigerated conditions (7 °C) and evaluated at weekly intervals for their sensory, chemical and microbial quality. The uncarbonated control samples were found to keep well till 5 weeks of storage while the carbonated beverage was acceptable up to 12 weeks of storage. Carbonation did not significantly alter the pH of the beverage, while a marginal increase in titratable acidity was recorded for the carbonated samples. Carbonation was found to arrest the development of lipolysis and proteolysis in the beverage during storage. Microbiological investigations established the inhibition of yeast and mold growth due to dissolved CO2.

  14. Short Communication Evidence of carbon transport between shelf ...

    The world ocean is pivotal in the global carbon cycle and, subsequent to anthropogenic loading of the atmosphere with CO2, its ability to sequestrate photosynthetically-fixed carbon is important with respect to our ability to predict climate change. A study of the Benguela Edge Exchange Processes was carried out to better ...

  15. Reservoir characteristics of middle pliocene deposits and their role in the formation of oil gas deposits of Azerbaijan shelf of the south Caspian

    Veliyeva, V.A.; Kabulova, A. Ya.

    2002-01-01

    Full text :Lithology-stratigraphical peculiarities of deposits of lower stage of productive series (P S) of Middle Pliocene their reservoir properties, correlation of individual horizons within the uplifts of the south Caspian was studied. Analysis of arenosity of lower stage of PS was studied. Azerbaijan shelf of South Caspian is located within depression zone of sedimentation basin generally, of Pliocene and post-Pliocene period of time, when sedimentation was mostly intensive and occurred in conditions of more deep sea basin. Azerbaijan shelf of south Caspian covers mainly two oil-gasp-bearing region as Absheron archipelago (north, north-eastern part of region) and Baku archipelago (southern part). Analysis of arenosity along the areas of the studied region showed, that in south-eastern direction and on the south eastern subsidence of each fold, as well as on the north-eastern wing their sand percent considerably increase whereas reservoir properties of sandy interbeds are improved

  16. Carbon dioxide storage in unconventional reservoirs workshop: summary of recommendations

    Jones, Kevin B.; Blondes, Madalyn S.

    2015-01-01

    “Unconventional reservoirs” for carbon dioxide (CO2) storage—that is, geologic reservoirs in which changes to the rock trap CO2 and therefore contribute to CO2 storage—including coal, shale, basalt, and ultramafic rocks, were the focus of a U.S. Geological Survey (USGS) workshop held March 28 and 29, 2012, at the National Conservation Training Center in Shepherdstown, West Virginia. The goals of the workshop were to determine whether a detailed assessment of CO2 storage capacity in unconventional reservoirs is warranted, and if so, to build a set of recommendations that could be used to develop a methodology to assess this storage capacity. Such an assessment would address only the technically available resource, independent of economic or policy factors. At the end of the workshop, participants agreed that sufficient knowledge exists to allow an assessment of the potential CO2 storage resource in coals, organic-rich shales, and basalts. More work remains to be done before the storage resource in ultramafic rocks can be meaningfully assessed.

  17. Carbon emission as a function of energy generation in hydroelectric reservoirs in Brazilian dry tropical biome

    Ometto, Jean P.; Cimbleris, André C.P.; Santos, Marco A. dos; Rosa, Luiz P.; Abe, Donato; Tundisi, José G.; Stech, José L.; Barros, Nathan; Roland, Fábio

    2013-01-01

    Most energy generation globally is fueled by coal and oil, raising concerns about greenhouse gas emissions. Hydroelectric reservoirs are anthropogenic aquatic systems that occur across a wide geographical extent, and, in addition to their importance for energy production, they have the potential to release two important greenhouse gases (GHGs), carbon dioxide and methane. We report results from an extensive study of eight hydroelectric reservoirs located in central and southeastern tropical Brazil. In the Brazilian dry tropical biome reservoirs, emissions (in tons of CO 2 Eq. per MW h) varied from 0.01 to 0.55, and decreased with reservoir age. Total emissions were higher in the reservoir lake when compared to the river downstream the dam; however, emissions per unit area, in the first kilometer of the river after the dam, were higher than that in the reservoir. The results showed, despite higher carbon emissions per energy production in the youngest reservoirs, lower emission from hydroelectric reservoirs from the studied region in relation to thermo electrical supply, fueled by coal or fossil fuel. The ratio emission of GHG per MWh produced is an important parameter in evaluating the service provided by hydroelectric reservoir and for energy planning policies. - Highlights: ► Hydroelectric reservoirs construction is growing worldwide. ► The effect of hydropower reservoir in the carbon cycle is dependent on environment characteristics. ► Carbon emissions per energy production are higher in the youngest tropical savannah reservoirs. ► Methane emissions decrease with reservoir age in tropical savannah reservoirs. ► In general, the effect of hydropower in the carbon cycle is lower than other energy sources

  18. Variations in organic carbon fluxes from Long Island Sound to the Continental Shelf

    Vlahos, P.; Whitney, M. M.

    2017-12-01

    Organic carbon balances for the Long Island Sound estuary over the years 2009-2012 are presented to assess the particulate and dissolved organic carbon contributions of the estuary to the adjacent shelf waters with respect to the Delaware and Chesapeake. Observations were coupled to a hydrodynamic model (ROMS) for both seasonal and annual estimates. During stratified summer periods, LIS was consistently a net exporter of OC to the continental shelf. LIS annual net carbon export however, varied with river flow. The heterotrophic or autotrophic nature of LIS also shifted seasonally and inter-annually. During the mass balance analysis period LIS ranged between net OC import from the continental shelf and heterotrophy in the lowest river flow year (2012) and net export of OC and autotrophy in the highest flow year (2011). Analysis suggests that LIS switches from net OC import to export when the annual river inputs exceed 19 km3 yr-1. Applying these thresholds to the annual river flow record suggests that net import occurred in 15% of the last 20 years and that LIS usually is a net exporter of OC (85%). Annually averaged LIS carbon export values based on river flow conditions over the last 20 yr are estimated at 56 ± 64 x 106 km3 yr-1. Analysis also suggests that LIS shifts from net heterotrophic to net autotrophic when annual river flow exceeds 26 km3 yr-1 (35% of the last 20 yr). Net heterotrophic conditions are most common, representing 65% of the last 20 yr.

  19. Microbial potential for carbon and nutrient cycling in a geogenic supercritical carbon dioxide reservoir.

    Freedman, Adam J E; Tan, BoonFei; Thompson, Janelle R

    2017-06-01

    Microorganisms catalyze carbon cycling and biogeochemical reactions in the deep subsurface and thus may be expected to influence the fate of injected supercritical (sc) CO 2 following geological carbon sequestration (GCS). We hypothesized that natural subsurface scCO 2 reservoirs, which serve as analogs for the long-term fate of sequestered scCO 2 , harbor a 'deep carbonated biosphere' with carbon cycling potential. We sampled subsurface fluids from scCO 2 -water separators at a natural scCO 2 reservoir at McElmo Dome, Colorado for analysis of 16S rRNA gene diversity and metagenome content. Sequence annotations indicated dominance of Sulfurospirillum, Rhizobium, Desulfovibrio and four members of the Clostridiales family. Genomes extracted from metagenomes using homology and compositional approaches revealed diverse mechanisms for growth and nutrient cycling, including pathways for CO 2 and N 2 fixation, anaerobic respiration, sulfur oxidation, fermentation and potential for metabolic syntrophy. Differences in biogeochemical potential between two production well communities were consistent with differences in fluid chemical profiles, suggesting a potential link between microbial activity and geochemistry. The existence of a microbial ecosystem associated with the McElmo Dome scCO 2 reservoir indicates that potential impacts of the deep biosphere on CO 2 fate and transport should be taken into consideration as a component of GCS planning and modelling. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. Sources, degradation and transport of terrigenous organic carbon on the East Siberian Arctic Shelf Seas

    Tesi, Tommaso; Semiletov, Igor; Dudarev, Oleg; Gustafsson, Örjan

    2013-04-01

    Recent studies suggest that the present hydrological regime increase observed in the Arctic rivers is mainly the consequence of the changes in permafrost conditions as a result of climate warming. Given the enormous amount of carbon stored in coastal and terrestrial permafrost the potentially increased supply from this large carbon pool to the coastal Arctic Ocean, possibly associated with a translocated release to the atmosphere as CO2, is considered a plausible scenario in a warming climate. However, there is not sufficient information regarding the reactivity of terrigenous material once supplied to the Arctic Ocean. In this study, we address this critical issue by examining the organic composition of surface sediments collected over extensive scales on the East Siberian Arctic Shelf (ESAS) as part of the International Siberian Shelf Study (ISSS). The ESAS represents by far the largest shelf of the Arctic Ocean. Samples were collected from the inner- to the outer-shelf following the sediment transport pathway in a region between the Lena and the Kolyma rivers. The analytical approach includes the characterization of marine and land-derived carbon using a large number of molecular biomarkers obtained by alkaline CuO oxidation such as lignin-phenols, cutin-derived products, p-hydroxy benzenes, benzoic acids, fatty acids, and dicarboxylic acids. Our results indicated high concentrations of terrigenous material in shallow sediments and a marked decrease of terrestrial biomarkers with increasing distance from the coastline. In parallel, lignin-based degradation proxies suggested highly altered terrigenous carbon in mid- and outer-shelf sediments compared to coastal sediments. Furthermore, the ratio of cutin-derived products over lignin significantly increased along the sediment transport pathway. Considering that cutin is considered to be intrinsically more reactive compared to lignin, high values of this ratio off the coastal region were interpreted as selective

  1. Numerical simulation of carbon dioxide effects in geothermal reservoirs

    Moya, S.L.; Iglesias, E.R. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-03-01

    We developed and coded a new equation of state (EOS) for water-carbon dioxide mixtures and coupled it to the TOUGH numerical simulator. This EOS is valid up to 350{degrees}C and 500 bar. Unlike previous thermodynamical models, it rigorously considers the non-ideal behavior of both components in the gaseous mixture and formally includes the effect of the compressibility of the liquid phase. We refer to the coupling of this EOS with TOUGH as TOUGH-DIOX. To complement this enhancement of TOUGH, we added indexed output files for easy selection and interpretation of results. We validated TOUGH-DIOX against published results. Furthermore we used TOUGH-DIOX to explore and compare mass and energy inflow performance relationships of geothermal wells with/without carbon dioxide (CO{sub 2}). Our results include the effects of a broad range of fluid and formation properties, initial conditions and history of reservoir production. This work contributes with generalized dimensionless inflow performance relationships appropriate for geothermal use.

  2. Cruziana traces from the Late Silurian (Pridoli carbonate shelf of Saaremaa, Estonia

    Olev Vinn

    2014-05-01

    Full Text Available Late Pridoli Cruziana traces have recently been found in carbonate shelf sediments of the Ohesaare Formation on Saaremaa Island, Estonia. Cruziana isp. is interpreted here as a locomotory trace (repichnia of an arthropod, possibly a trilobite. Cruziana traces previously known from the Silurian of Baltica differ from Cruziana isp., indicating that the diversity of Cruziana traces in the late Silurian of Baltica was higher than previously thought.

  3. STRONTIUM ISOTOPE STRATIGRAPHY AS A CONTRIBUTION FOR DATING MIOCENE SHELF CARBONATES (S. MARINO FM., NORTHERN APENNINES

    CLAUDIO ARGENTINO

    2017-01-01

    Full Text Available This paper provides new data on strontium isotope stratigraphy applied to the Miocene heterozoan shelfal carbonates of the S. Marino Fm. (Marecchia Valley, northern Apennines. Sr isotopic analyses were carried out on oyster shells, bryozoans and bulk-rocks from the lower-middle carbonate portion of the section. In the upper part of the succession that shows evidence of detrital influx,87Sr/86Sr analyses were performed on foraminifera tests, separating planktonic and benthic forms. Results were compared with calcareous nannofossil biostratigraphic data from the same levels, in order to test the reliability of Sr dating in mixed carbonate-siliciclastic sediments. Mean ages obtained from oysters range between 16.9 Ma and 16.3 Ma. Very similar results are obtained using bryozoans (16.5 Ma to 16.1 Ma and bulk-rocks (16.8 Ma to 16.2 Ma. These results allow to better constrain the age of the massive carbonate shelf, referable to the upper Burdigalian. In the upper carbonate-siliciclastic portion of the shelf, numerical ages obtained from planktonic and benthic foraminifera are in good agreement with nannofossil biozones (mean ages respectively around 15.3 Ma and 14.5 Ma although they display wide confidence intervals. These wide age uncertainties depend on the slow rate of change of marine 87Sr/86Sr through time that characterizes the interval between ~15 and ~13.5 Ma.

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

    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.

  5. Feasibility study on application of volume acid fracturing technology to tight gas carbonate reservoir development

    Nianyin Li

    2015-09-01

    Full Text Available How to effectively develop tight-gas carbonate reservoir and achieve high recovery is always a problem for the oil and gas industry. To solve this problem, domestic petroleum engineers use the combination of the successful experiences of North American shale gas pools development by stimulated reservoir volume (SRV fracturing with the research achievements of Chinese tight gas development by acid fracturing to propose volume acid fracturing technology for fractured tight-gas carbonate reservoir, which has achieved a good stimulation effect in the pilot tests. To determine what reservoir conditions are suitable to carry out volume acid fracturing, this paper firstly introduces volume acid fracturing technology by giving the stimulation mechanism and technical ideas, and initially analyzes the feasibility by the comparison of reservoir characteristics of shale gas with tight-gas carbonate. Then, this paper analyzes the validity and limitation of the volume acid fracturing technology via the analyses of control conditions for volume acid fracturing in reservoir fracturing performance, natural fracture, horizontal principal stress difference, orientation of in-situ stress and natural fracture, and gives the solution for the limitation. The study results show that the volume acid fracturing process can be used to greatly improve the flow environment of tight-gas carbonate reservoir and increase production; the incremental or stimulation response is closely related with reservoir fracturing performance, the degree of development of natural fracture, the small intersection angle between hydraulic fracture and natural fracture, the large horizontal principal stress difference is easy to form a narrow fracture zone, and it is disadvantageous to create fracture network, but the degradable fiber diversion technology may largely weaken the disadvantage. The practices indicate that the application of volume acid fracturing process to the tight-gas carbonate

  6. Methane production by Methanothermobacter thermautotrophicus to recover energy from carbon dioxide sequestered in geological reservoirs.

    Kawaguchi, Hideo; Sakuma, Takahiro; Nakata, Yuiko; Kobayashi, Hajime; Endo, Keita; Sato, Kozo

    2010-07-01

    To recover energy from carbon dioxide sequestered in geological reservoirs, the geochemical effects of acidic and substrate- and nutrient-limiting conditions on methane production by the hydrogenotrophic methanogen Methanothermobacter thermautotrophicus were investigated in a simulated deep saline aquifer environment using formation water media retrieved from petroleum reservoirs. 2009 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  7. Seasonal distribution of dissolved inorganic carbon and net community production on the Bering Sea shelf

    J. T. Mathis

    2010-05-01

    Full Text Available In order to assess the current state of net community production (NCP in the southeastern Bering Sea, we measured the spatio-temporal distribution and controls on dissolved inorganic carbon (DIC concentrations in spring and summer of 2008 across six shelf domains defined by differing biogeochemical characteristics. DIC concentrations were tightly coupled to salinity in spring and ranged from ~1900 μmoles kg−1 over the inner shelf to ~2400 μmoles kg−1 in the deeper waters of the Bering Sea. In summer, DIC concentrations were lower due to dilution from sea ice melt, terrestrial inputs, and primary production. Concentrations were found to be as low ~1800 μmoles kg−1 over the inner shelf. We found that DIC concentrations were drawn down 30–150 μmoles kg−1 in the upper 30 m of the water column due to primary production and calcium carbonate formation between the spring and summer occupations. Using the seasonal drawdown of DIC, estimated rates of NCP on the inner, middle, and outer shelf averaged 28 ± 9 mmoles C m−2 d−1. However, higher rates of NCP (40–47 mmoles C m−2 d−1 were observed in the "Green Belt" where the greatest confluence of nutrient-rich basin water and iron-rich shelf water occurs. We estimated that in 2008, total NCP across the shelf was on the order of ~96 Tg C yr−1. Due to the paucity of consistent, comparable productivity data, it is impossible at this time to quantify whether the system is becoming more or less productive. However, as changing climate continues to modify the character of the Bering Sea, we have shown that NCP can be an important indicator of how the ecosystem is functioning.

  8. High-Performance Modeling of Carbon Dioxide Sequestration by Coupling Reservoir Simulation and Molecular Dynamics

    Bao, Kai; Yan, Mi; Allen, Rebecca; Salama, Amgad; Lu, Ligang; Jordan, Kirk E.; Sun, Shuyu; Keyes, David E.

    2015-01-01

    The present work describes a parallel computational framework for carbon dioxide (CO2) sequestration simulation by coupling reservoir simulation and molecular dynamics (MD) on massively parallel high-performance-computing (HPC) systems

  9. Experimental studies of low salinity water flooding in carbonate reservoirs: A new promising approach

    Zahid, Adeel; Shapiro, Alexander; Skauge, Arne

    2012-01-01

    Low salinity water flooding is well studied for sandstone reservoirs, both laboratory and field tests have showed improvement in the oil recovery in many cases. Up to very recently, the low salinity effect has been indeterminated for carbonates. Most recently, Saudi Aramco reported that substantial...... additional oil recovery can be achieved when successively flooding composite carbonate core plugs with various diluted versions of seawater. The experimental data on carbonates is very limited, so more data and better understanding of the mechanisms involved is needed to utilize this method for carbonate...... reservoirs. In this paper, we have experimentally investigated the oil recovery potential of low salinity water flooding for carbonate rocks. We used both reservoir carbonate and outcrop chalk core plugs. The flooding experiments were carried out initially with the seawater, and afterwards additional oil...

  10. Acoustic Impedance Inversion To Identify Oligo-Miocene Carbonate Facies As Reservoir At Kangean Offshore Area

    Zuli Purnama, Arif; Ariyani Machmud, Pritta; Eka Nurcahya, Budi; Yusro, Miftahul; Gunawan, Agung; Rahmadi, Dicky

    2018-03-01

    Model based inversion was applied to inversion process of 2D seismic data in Kangean Offshore Area. Integration acoustic impedance from wells and seismic data was expected showing physical property, facies separation and reservoir quality of carbonate rock, particularly in Kangean Offshore Area. Quantitative and qualitative analysis has been conducted on the inversion results to characterize the carbonate reservoir part of Kujung and correlate it to depositional facies type. Main target exploration in Kangean Offshore Area is Kujung Formation (Oligo-Miocene Carbonate). The type of reservoir in this area generate from reef growing on the platform. Carbonate rock is a reservoir which has various type and scale of porosity. Facies determination is required to to predict reservoir quality, because each facies has its own porosity value. Acoustic impedance is used to identify and characterize Kujung carbonate facies, also could be used to predict the distribution of porosity. Low acoustic impedance correlated with packstone facies that has acoustic impedance value below 7400 gr/cc*m/s. In other situation, high acoustic impedance characterized by wackestone facies above 7400 gr/cc*m/s. The interpretation result indicated that Kujung carbonate rock dominated by packstone facies in the upper part of build-up and it has ideal porosity for hydrocarbon reservoir.

  11. Sources and turnover of organic carbon and methane in fjord and shelf sediments off northern Norway

    Sauer, Simone; Hong, Wei-Li; Knies, Jochen; Lepland, Aivo; Forwick, Matthias; Klug, Martin; Eichinger, Florian; Baranwal, Soma; Crémière, Antoine; Chand, Shyam; Schubert, Carsten J.

    2016-10-01

    To better understand the present and past carbon cycling and transformation processes in methane-influenced fjord and shelf areas of northern Norway, we compared two sediment cores from the Hola trough and from Ullsfjorden. We investigated (1) the organic matter composition and sedimentological characteristics to study the sources of organic carbon (Corg) and the factors influencing Corg burial, (2) pore water geochemistry to determine the contribution of organoclastic sulfate reduction and methanogenesis to total organic carbon turnover, and (3) the carbon isotopic signature of hydrocarbons to identify the carbon transformation processes and gas sources. High sedimentation and Corg accumulation rates in Ullsfjorden support the notion that fjords are important Corg sinks. The depth of the sulfate-methane-transition (SMT) in the fjord is controlled by the supply of predominantly marine organic matter to the sediment. Organoclastic sulfate reduction accounts for 60% of the total depth-integrated sulfate reduction in the fjord. In spite of the presence of ethane, propane, and butane, we suggest a purely microbial origin of light hydrocarbons in the sediments based on their low δ13C values. In the Hola trough, sedimentation and Corg accumulation rates changed during the deglacial-to-post-glacial transition from approximately 80 cm ka-1 to erosion at present. Thus, Corg burial in this part of the shelf is presently absent. Low organic matter content in the sediment and low rates of organoclastic sulfate reduction (only 3% of total depth-integrated sulfate reduction) entail that the shallow depth of the SMT is controlled mostly by ascending thermogenic methane from deeper sources.

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

    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.

  13. Carbon dioxide dynamics in a lake and a reservoir on a tropical island (Bali, Indonesia).

    Macklin, Paul A; Suryaputra, I Gusti Ngurah Agung; Maher, Damien T; Santos, Isaac R

    2018-01-01

    Water-to-air carbon dioxide fluxes from tropical lakes and reservoirs (artificial lakes) may be an important but understudied component of global carbon fluxes. Here, we investigate the seasonal dissolved carbon dioxide (CO2) dynamics in a lake and a reservoir on a tropical volcanic island (Bali, Indonesia). Observations were performed over four seasonal surveys in Bali's largest natural lake (Lake Batur) and largest reservoir (Palasari Reservoir). Average CO2 partial pressures in the natural lake and reservoir were 263.7±12.2 μatm and 785.0±283.6 μatm respectively, with the highest area-weighted partial pressures in the wet season for both systems. The strong correlations between seasonal mean values of dissolved oxygen (DO) and pCO2 in the natural lake (r2 = 0.92) suggest that surface water metabolism was an important driver of CO2 dynamics in this deep system. Radon (222Rn, a natural groundwater discharge tracer) explained up to 77% of the variability in pCO2 in the shallow reservoir, suggesting that groundwater seepage was the major CO2 driver in the reservoir. Overall, the natural lake was a sink of atmospheric CO2 (average fluxes of -2.8 mmol m-2 d-1) while the reservoir was a source of CO2 to the atmosphere (average fluxes of 7.3 mmol m-2 d-1). Reservoirs are replacing river valleys and terrestrial ecosystems, particularly throughout developing tropical regions. While the net effect of this conversion on atmospheric CO2 fluxes remains to be resolved, we speculate that reservoir construction will partially offset the CO2 sink provided by deep, volcanic, natural lakes and terrestrial environments.

  14. HETEROGENEOUS SHALLOW-SHELF CARBONATE BUILDUPS IN THE PARADOX BASIN, UTAH AND COLORADO: TARGETS FOR INCREASED OIL PRODUCTION AND RESERVES USING HORIZONTAL DRILLING TECHNIQUES. Semi-annual Technical Report October 6, 2002 - April 5, 2003

    Eby, David E.; Chidsey, Thomas C. Jr.; McClure, Kevin; Morgan, Craig D.

    2003-01-01

    The Paradox Basin of Utah, Colorado, Arizona, and New Mexico contains nearly 100 small oil fields producing from carbonate buildups within the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to 10 wells with primary production ranging from 700,000 to 2,000,000 barrels (111,300-318,000 m 3 ) of oil per field and a 15 to 20 percent recovery rate. At least 200 million barrels (31.8 million m 3 ) of oil will not be recovered from these small fields because of inefficient recovery practices and undrained heterogeneous reservoirs. Several fields in southeastern Utah and southwestern Colorado are being evaluated as candidates for horizontal drilling and enhanced oil recovery from existing vertical wells based upon geological characterization and reservoir modeling case studies. Geological characterization on a local scale is focused on reservoir heterogeneity, quality, and lateral continuity, as well as possible reservoir compartmentalization, within these fields. This study utilizes representative cores, geophysical logs, and thin sections to characterize and grade each field's potential for drilling horizontal laterals from existing development wells. The results of these studies can be applied to similar fields elsewhere in the Paradox Basin and the Rocky Mountain region, the Michigan and Illinois Basins, and the Midcontinent region. This report covers research activities for the second half of the third project year (October 6, 2002, through April 5, 2003). The primary work included describing and mapping regional facies of the upper Ismay and lower Desert Creek zones of the Paradox Formation in the Blanding sub-basin, Utah. Regional cross sections show the development of ''clean carbonate'' packages that contain all of the productive reservoir facies. These clean carbonates abruptly change laterally into thick anhydrite packages that filled several small intra-shelf basins in the upper Ismay zone. Examination of upper Ismay cores

  15. Heterogeneous Shallow-Shelf Carbonate Buildups in the Paradox Basin, Utah and Colorado: Targets for Increased Oil Production and Reserves Using Horizontal Drilling Techniques; SEMIANNUAL

    Chidsey, Thomas C. Jr.; Eby, David E.; Wray, Laural L.

    2001-01-01

    The project's primary objective was to enhance domestic petroleum production by demonstration and transfer of horizontal drilling technology in the Paradox Basin, Utah, Colorado, Arizona, and New Mexico. If this project can demonstrate technical and economic feasibility, then the technique can be applied to approximately 100 additional small fields in the Paradox Basin alone, and result in increased recovery of 25 to 50 million barrels (4-8 million m3) of oil. This project was designed to characterize several shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation, choose the best candidate(s) for a pilot demonstration project to drill horizontally from existing vertical wells, monitor well performance(s), and report associated validation activities

  16. Consideration of clay in rocks in discriminating carbonate reservoirs in Eastern Turkmenia

    Ehjvazov, A.M.

    1975-01-01

    A method is described for calculating the clayiness of rocks in discrimination of carbonate reservoirs of eastern Turkmenia. Carbonate deposits in eastern Turkmenia contain significant amounts of clayey material, which interferes with the collector properties of the rocks. However, in many cases the clayey limestones, when sampled, give industrial supplies of gas. Analysis of gamma-logging data with calculation of the results of sampling for layers of different porosities, as determined from the results of neutron gamma logging, showed a definite correlation between the reservoir properties of carbonate layers and the values of ΔIsub(γ) of two different gamma-logging parameters, calculated by the single ''reference'' horizon method

  17. Bulk and Surface Aqueous Speciation of Calcite: Implications for Low-Salinity Waterflooding of Carbonate Reservoirs

    Yutkin, Maxim P.

    2017-08-25

    Low-salinity waterflooding (LSW) is ineffective when reservoir rock is strongly water-wet or when crude oil is not asphaltenic. Success of LSW relies heavily on the ability of injected brine to alter surface chemistry of reservoir crude-oil brine/rock (COBR) interfaces. Implementation of LSW in carbonate reservoirs is especially challenging because of high reservoir-brine salinity and, more importantly, because of high reactivity of the rock minerals. Both features complicate understanding of the COBR surface chemistries pertinent to successful LSW. Here, we tackle the complex physicochemical processes in chemically active carbonates flooded with diluted brine that is saturated with atmospheric carbon dioxide (CO2) and possibly supplemented with additional ionic species, such as sulfates or phosphates. When waterflooding carbonate reservoirs, rock equilibrates with the injected brine over short distances. Injected-brine ion speciation is shifted substantially in the presence of reactive carbonate rock. Our new calculations demonstrate that rock-equilibrated aqueous pH is slightly alkaline quite independent of injected-brine pH. We establish, for the first time, that CO2 content of a carbonate reservoir, originating from CO2-rich crude oil and gas, plays a dominant role in setting aqueous pH and rock-surface speciation. A simple ion-complexing model predicts the calcite-surface charge as a function of composition of reservoir brine. The surface charge of calcite may be positive or negative, depending on speciation of reservoir brine in contact with the calcite. There is no single point of zero charge; all dissolved aqueous species are charge determining. Rock-equilibrated aqueous composition controls the calcite-surface ion-exchange behavior, not the injected-brine composition. At high ionic strength, the electrical double layer collapses and is no longer diffuse. All surface charges are located directly in the inner and outer Helmholtz planes. Our evaluation of

  18. Bottom currents and sediment waves on a shallow carbonate shelf, Northern Carnarvon Basin, Australia

    Belde, Johannes; Reuning, Lars; Back, Stefan

    2017-04-01

    The modern seafloor of the Australian Northwest Shelf between Exmouth and Dampier was analyzed for large scale sedimentary bedforms on 3D seismic reflection data. The Carnarvon MegaSurvey of Petroleum Geo-Services (PGS), a merged dataset of multiple industrial 3D seismic reflection surveys with a total size of 49,717 km2, offers an extensive view of the continental shelf, slope and rise of the Northern Carnarvon Basin. Over the shelf two fields of large scale sediment waves were observed in water depths between 55-130 m, where the seafloor may be influenced by different processes including internal waves, tides and storms. Based on the dimensions and orientations of the sediment waves the dominant direction and approximate strength of local bottom currents could be estimated. Information on local sediment grain-size distribution was provided by the auSEABED database allowing a classification of the observed sediment waves into sand- or mudwaves. The first sediment wave field is positioned northwest of the Montebello Islands where the shelf is comparatively narrow and local sediment is mainly sand-sized. It most likely formed by increased bottom currents induced by the diversion of tidal flows around the islands. The second sediment wave field is located north of the Serrurier and Bessieres Islands within a local seafloor depression. Local sediments are poorly sorted, containing significant amounts of mud and gravel in addition to the mainly sand-sized grains. The coarser sediment fraction could have been reworked to sandwaves by cyclone-induced bottom currents. Alternatively, the finer sediment fraction could form mudwaves shaped by less energetic along-slope oriented currents in the topographic depression. The sediment waves consist partially of carbonate grains such as ooids and peloids that formed in shallow water during initial stages of the post glacial sea-level rise. These stranded carbonate grains thus formed in a different environment than the sediment

  19. Carbon flow dynamics in the pelagic community of the Sau Reservoir (Catalonia, NE Spain)

    Comerma, M.; García, J. C.; Romero, M.; Armengol, J.; Šimek, Karel

    2003-01-01

    Roč. 504, - (2003), s. 87-98 ISSN 0018-8158. [Reservoir Limnology and Water Quality /4./. České Budějovice, 12.08.2002-16.08.2002] Institutional research plan: CEZ:AV0Z6017912 Keywords : reservoir * longitudinal plankton succession * carbon flow through microbial food webs Subject RIV: EE - Microbiology, Virology Impact factor: 0.720, year: 2003

  20. Seasonal Dynamics of Dissolved Organic Carbon Under Complex Circulation Schemes on a Large Continental Shelf: The Northern South China Sea

    Meng, Feifei; Dai, Minhan; Cao, Zhimian; Wu, Kai; Zhao, Xiaozheng; Li, Xiaolin; Chen, Junhui; Gan, Jianping

    2017-12-01

    We examined the distribution and seasonality of dissolved organic carbon (DOC) based on a large data set collected from the northern South China Sea (NSCS) shelf under complex circulation schemes influenced by river plume, coastal upwelling, and downwelling. The highest surface values of ˜117 μmol L-1 were observed nearshore in summer suggesting high DOC supplies from the river inputs, whereas the lowest surface values of ˜62 μmol L-1 were on the outer shelf in winter due to entrainment of DOC-poor subsurface water under strengthened vertical mixing. While the summer coastal upwelling brought lower DOC from offshore depth to the nearshore surface, the winter coastal downwelling delivered higher surface DOC to the midshelf deep waters from the inner shelf fueled by the China Coastal Current (CCC) transporting relatively high DOC from the East China Sea to the NSCS. The intensified winter downwelling generated a cross-shelf DOC transport of 3.1 × 1012 g C over a large shelf area, which induced a significant depression of the NSCS DOC inventory in winter relative to in autumn. In addition to the variable physical controls, net biological production of DOC was semiquantified in both the river plume (2.8 ± 3.0 μmol L-1) and coastal upwelling (3.1 ± 1.3 μmol L-1) in summer. We demonstrated that the NSCS shelf had various origins of DOC including riverine inputs, inter-shelf transport and in situ production. Via cross-shelf transport, the accumulated DOC would be exported to and stored in the deep ocean, suggesting that continental shelves are a potentially effective carbon sink.

  1. Porosity-depth trends of carbonate deposits along the northwest shelf of Australia (IODP Expedition 356)

    Lee, Eun Young; Kominz, Michelle; Reuning, Lars; Takayanagi, Hideko; Knierzinger, Wolfgang; Wagreich, Michael; Expedition 356 shipboard scientists, IODP

    2017-04-01

    The northwest shelf (NWS) of Australia extends from northern tropical to southern temperate latitudes situated offshore from the low-moderate-relief and semi-arid Australian continent. The shelf environment is dominated throughout by carbonate sedimentation with warm-water and tropical carbonate deposits, connected to the long-term northward drift of Australia bringing the NWS into tropical latitudes. IODP expedition 356 cored seven sites (U1458-U1464) covering a latitudinal range of 29°S-18°S off the NWS. This study focuses on porosity-depth trends of the Miocene - Pleistocene carbonate sediment on the NWS. The NWS is an ideal area to study regional (and furthermore general) carbonate porosity-depth relationships, because it contains a nearly continuous sequence of carbonate sediment ranging in depth from the surface to about 1,100m and in age from Pleistocene to Miocene. Porosity-depth trends of sedimentary rocks are generally controlled by a variety of factors which govern the rates of porosity loss due to mechanical compaction and of porosity loss (or gain) due to chemical processes during diagenesis. This study derives porosity data from Moisture and Density (MAD) technique conducted during IODP Expedition 356. MAD samples were collected from packstone (44%), wackestone (27%), mudstone (15%) and grainstone (7%), with the rest from floatstone, rudstone, dolostone, sandstone and other subordinate lithologies. To understand porosity-depth trends, the porosity data are arranged both exponentially and linearly, and correlated with age models and lithologic descriptions provided by IODP shipboard scientists. Porosity(%)-depth(m) trends of all the porosity data are Porosity=52e-0.0008/Depth (exponential) and Porosity=-0.03Depth+52 (linear). Porosities near surface and in the deepest parts of each well are least well represented by these trend lines. Porosity values of Pleistocene sediment are generally higher than those of Miocene - Pliocene sediment. The initial

  2. CO{sub 2} huff-n-puff process in a light oil shallow carbonate reservoir. Annual report, January 1, 1996--December 31, 1996

    Prieditis, J.; Wehner, S.

    1998-01-01

    The application of cyclic CO{sub 2}, often referred to as the CO{sub 2} Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO{sub 2} H-n-P process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in the capital intensive miscible projects. Texaco Exploration & Production Inc. and the U.S. Department of Energy have teamed up in an attempt to develop the CO{sub 2} Huff-n-Puff process in the Grayburg and San Andres formations; a light oil, shallow shelf carbonate reservoir that exists throughout the Permian Basin. A significant amount of oil reserves are located in carbonate reservoirs. Specifically, the carbonates deposited in shallow shelf (SSC) environments make up the largest percentage of known reservoirs within the Permian Basin of North America. Many of these known resources have been under waterflooding operations for decades and are at risk of abandonment if crude oil recoveries cannot be economically enhanced. The selected site for this demonstration project is the Central Vacuum Unit waterflood in Lea County, New Mexico. Miscible CO{sub 2} flooding is the process of choice for enhancing recovery of light oils and already accounts for over 12% of the Permian Basin`s daily production. There are significant probable reserves associated with future miscible CO{sub 2} projects. However, many are marginally economic at current market conditions due to large up-front capital commitments for a peak response which may be several years in the future. The resulting negative cash-flow is sometimes too much for an operator to absorb. The CO{sub 2} H-n-P process is being investigated as a near-term option to mitigate the negative cash-flow situation--allowing acceleration of inventoried miscible CO{sub 2} projects when coupled together.

  3. Controls on reef development and the terrigenous-carbonate interface on a shallow shelf, Nicaragua (Central America)

    Roberts, H. H.; Murray, S. P.

    1983-06-01

    Marine geology and physical oceanographic data collected during two field projects (˜4 months) on the Caribbean shelf of Nicaragua indicate a surprising dominance of carbonate deposition and reef growth on a shelf that is receiving an abnormally large volume of terrigenous sediments. High rainfall rates (˜400 500 cm/year), coupled with a warm tropical climate, encourage rapid denudation of the country's central volcanic highland and transport of large volumes of terrigenous sediment and fresh water to the coast. Estimates suggest that three times more fresh water and fifteen times more sediment are introduced per unit length of coastline than on the east coast of the United States. Distribution of the terrigenous facies, development of carbonate sediment suites, and the location and quality of viable reefs are strongly controlled by the dynamic interaction near the coasts of highly turbid fresh to brackish water effluents from thirteen rivers with clear marine waters of the shelf. Oceanic water from the central Caribbean drift current intersects the shelf and moves slowely in a dominant northwest direction toward the Yucatan Channel. A sluggish secondary gyre moves to the south toward Costa Rica. In contrast, the turbid coastal water is deflected to the south in response to density gradients, surface water slopes, and momentum supplied by the steady northeast trade winds. A distinct two-layered flow is commonly present in the sediment-rich coastal boundary zone, which is typically 10 20 km wide. The low-salinity upper layer is frictionally uncoupled from the ambient shelf water and therefore can expand out of the normally coherent coastal boundary zone during periods of abnormal flooding or times when instability is introduced into the northeast trades. Reef distribution, abruptness of the terrigenous-carbonate interface, and general shelf morphology reflect the long-term dynamic structure of the shelf waters. A smooth-bottomed ramp of siliciclastic sands to

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

    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.

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

    Katterbauer, Klemens; Arango, Santiago; Sun, Shuyu; Hoteit, Ibrahim

    2016-01-01

    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

  6. Palaeoecology of a 3-kyr biosedimentary record of a coral reef-supporting carbonate shelf

    Almeida, Carine M.; Barbosa, Catia Fernandes; Cordeiro, Renato C.; Seoane, José Carlos S.; Fermino, Gerson M.; Silva, Patricia O.; Turcq, Bruno J.

    2013-11-01

    This study assesses the 3-kyr paleoecology and sedimentary evolution of the Abrolhos carbonate shelf, Bahia, Brazil, using a two-meter-long core collected in a carbonate muddy sediment. The paleoecology was based on the distribution of benthic foraminifer functional groups associated with grain size, total organic carbon (TOC), total nitrogen (TN), C/N and δ13C. The results identified three biosedimentary units showing that symbiont-bearing foraminifers (Peneroplis and Archaias) decrease in abundance. However, other small taxa (Miliolinella and Cornuspira) and stress-tolerant genera (Bolivina, Elphidium and Ammonia) increase in abundance toward the core top. Grain size decreases toward the top of the core, suggesting a weakening of hydrodynamic winnowing toward recent time. The TOC and TN concentrations increase, and the C/N ratios decrease, suggesting an increase of marine productivity from nearby goblet-shaped structures called "chapeirões". Changes in the benthic foraminifer community can be linked to the sedimentological and organic matter input, which are the result of climatic and oceanographic variations at different spatial and time scales, thus illustrating reduced potential to support symbiont-bearing foraminifer communities to the end of the Holocene.

  7. A method for the assessment of long-term changes in carbon stock by construction of a hydropower reservoir.

    Bernardo, Julio Werner Yoshioka; Mannich, Michael; Hilgert, Stephan; Fernandes, Cristovão Vicente Scapulatempo; Bleninger, Tobias

    2017-09-01

    Sustainability of hydropower reservoirs has been questioned since the detection of their greenhouse gas (GHG) emissions which are mainly composed of carbon dioxide and methane. A method to assess the impact on the carbon cycle caused by the transition from a natural river system into a reservoir is presented and discussed. The method evaluates the long term changes in carbon stock instead of the current approach of monitoring and integrating continuous short term fluxes. A case study was conducted in a subtropical reservoir in Brazil, showing that the carbon content within the reservoir exceeds that of the previous landuse. The average carbon sequestration over 43 years since damming was 895 mg C m[Formula: see text] and found to be mainly due to storage of carbon in sediments. These results demonstrate that reservoirs have two opposite effects on the balance of GHGs. By storing organic C in sediments, reservoirs are an important carbon sink. On the other hand, reservoirs increase the flux of methane into the atmosphere. If the sediments of reservoirs could be used for long term C storage, reservoirs might have a positive effect on the balance of GHGs.

  8. Modelling of Salt Solubilities for Smart Water flooding in Carbonate Reservoirs using Extended UNIQUAC Model

    Chakravarty, Krishna Hara

    recovery can increase that capture up to 25-30% of original oil in place (OOIP). But cost effective Enhanced Oil Recovery (EOR) techniques if implemented correctly canbe used to produce another 10-15% of the initially available hydrocarbons. Advanced water flooding (i.e. altering injection brine...... compositions by varying concentration of selected ions) is an enhanced oil recovery method which in alow cost, non-toxic manner increases oil recovery from various carbonate reservoirs. Dan and Halfdan are chalk reservoirs from the Danish North Sea, which are matured oil fields that have been flooded......For most oil reservoirs which were drilled with conventional methods, the expected initial recovery of available hydrocarbons maybe as low as 15% – thusleaving 85+% of hydrocarbons in the reservoir. Implementation of mechanical methods including pump jacks and initial gas injection or thermal...

  9. Seagrass meadows as a globally significant carbonate reservoir

    Mazarrasa, I.; Marbà , N.; Lovelock, C. E.; Serrano, O.; Lavery, P. S.; Fourqurean, J. W.; Kennedy, H.; Mateo, M. A.; Krause-Jensen, D.; Steven, A. D. L.; Duarte, Carlos M.

    2015-01-01

    There has been growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the particulate organic carbon (POC) stocks and accumulation rates and ignored the particulate inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass sediments using a synthesis of published and unpublished data on sediment carbonate concentration from 403 vegetated and 34 adjacent un-vegetated sites. PIC stocks in the top 1 m of sediment ranged between 3 and 1660 Mg PIC ha−1, with an average of 654 ± 24 Mg PIC ha−1, exceeding those of POC reported in previous studies by about a factor of 5. Sedimentary carbonate stocks varied across seagrass communities, with meadows dominated by Halodule, Thalassia or Cymodocea supporting the highest PIC stocks, and tended to decrease polewards at a rate of −8 ± 2 Mg PIC ha−1 per degree of latitude (general linear model, GLM; p < 0.0003). Using PIC concentrations and estimates of sediment accretion in seagrass meadows, the mean PIC accumulation rate in seagrass sediments is found to be 126.3 ± 31.05 g PIC m−2 yr−1. Based on the global extent of seagrass meadows (177 000 to 600 000 km2), these ecosystems globally store between 11 and 39 Pg of PIC in the top metre of sediment and accumulate between 22 and 75 Tg PIC yr−1, representing a significant contribution to the carbonate dynamics of coastal areas. Despite the fact that these high rates of carbonate accumulation imply CO2

  10. Seagrass meadows as a globally significant carbonate reservoir

    Mazarrasa, I.

    2015-08-24

    There has been growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the particulate organic carbon (POC) stocks and accumulation rates and ignored the particulate inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass sediments using a synthesis of published and unpublished data on sediment carbonate concentration from 403 vegetated and 34 adjacent un-vegetated sites. PIC stocks in the top 1 m of sediment ranged between 3 and 1660 Mg PIC ha−1, with an average of 654 ± 24 Mg PIC ha−1, exceeding those of POC reported in previous studies by about a factor of 5. Sedimentary carbonate stocks varied across seagrass communities, with meadows dominated by Halodule, Thalassia or Cymodocea supporting the highest PIC stocks, and tended to decrease polewards at a rate of −8 ± 2 Mg PIC ha−1 per degree of latitude (general linear model, GLM; p < 0.0003). Using PIC concentrations and estimates of sediment accretion in seagrass meadows, the mean PIC accumulation rate in seagrass sediments is found to be 126.3 ± 31.05 g PIC m−2 yr−1. Based on the global extent of seagrass meadows (177 000 to 600 000 km2), these ecosystems globally store between 11 and 39 Pg of PIC in the top metre of sediment and accumulate between 22 and 75 Tg PIC yr−1, representing a significant contribution to the carbonate dynamics of coastal areas. Despite the fact that these high rates of carbonate accumulation imply CO2

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

    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.

  12. Transient pressure and productivity analysis in carbonate geothermal reservoirs with changing external boundary flux

    Wang Dongying

    2017-01-01

    Full Text Available In this paper, a triple-medium flow model for carbonate geothermal reservoirs with an exponential external boundary flux is established. The pressure solution under constant production conditions in Laplace space is solved. The geothermal wellbore pressure change considering wellbore storage and skin factor is obtained by Stehfest numerical inversion. The well test interpretation charts and Fetkovich production decline chart for carbonate geothermal reservoirs are proposed for the first time. The proposed Fetkovich production decline curves are applied to analyze the production decline behavior. The results indicate that in carbonate geothermal reservoirs with exponential external boundary flux, the pressure derivative curve contains a triple dip, which represents the interporosity flow between the vugs or matrix and fracture system and the invading flow of the external boundary flux. The interporosity flow of carbonate geothermal reservoirs and changing external boundary flux can both slow down the extent of production decline and the same variation tendency is observed in the Fetkovich production decline curve.

  13. Carbon mineralization and carbonate preservation in modern cold-water coral reef sediments on the Norwegian shelf

    L. M. Wehrmann

    2009-04-01

    Full Text Available Cold-water coral ecosystems are considered hot-spots of biodiversity and biomass production and may be a regionally important contributor to carbonate production. The impact of these ecosystems on biogeochemical processes and carbonate preservation in associated sediments were studied at Røst Reef and Traenadjupet Reef, two modern (post-glacial cold-water coral reefs on the Mid-Norwegian shelf. Sulfate and iron reduction as well as carbonate dissolution and precipitation were investigated by combining pore-water geochemical profiles, steady state modeling, as well as solid phase analyses and sulfate reduction rate measurements on gravity cores of up to 3.25 m length. Low extents of sulfate depletion and dissolved inorganic carbon (DIC production, combined with sulfate reduction rates not exceeding 3 nmol S cm−3 d−1, suggested that overall anaerobic carbon mineralization in the sediments was low. These data showed that the coral fragment-bearing siliciclastic sediments were effectively decoupled from the productive pelagic ecosystem by the complex reef surface framework. Organic matter being mineralized by sulfate reduction was calculated to consist of 57% carbon bound in CH2O groups and 43% carbon in -CH2- groups. Methane concentrations were below 1 μM, and failed to support the hypothesis of a linkage between the distribution of cold-water coral reefs and the presence of hydrocarbon seepage. Reductive iron oxide dissolution linked to microbial sulfate reduction buffered the pore-water carbonate system and inhibited acid-driven coral skeleton dissolution. A large pool of reactive iron was available leading to the formation of iron sulfide minerals. Constant pore-water Ca2+, Mg2+ and Sr2+ concentrations in most cores and decreasing Ca2+ and Sr2+ concentrations with depth in core 23–18 GC indicated diagenetic carbonate precipitation. This was

  14. Summertime calcium carbonate undersaturation in shelf waters of the western Arctic Ocean – how biological processes exacerbate the impact of ocean acidification

    N. R. Bates; M. I. Orchowska; R. Garley; J. T. Mathis

    2013-01-01

    The Arctic Ocean accounts for only 4% of the global ocean area, but it contributes significantly to the global carbon cycle. Recent observations of seawater CO2-carbonate chemistry in shelf waters of the western Arctic Ocean, primarily in the Chukchi Sea, from 2009 to 2011 indicate that bottom waters are seasonally undersaturated with respect to calcium carbonate (CaCO3) minerals, particularly aragonite. Nearly 40% of sampled bottom waters on the shelf have saturation states...

  15. Detrital Carbonate Events on the Labrador Shelf, a 13 to 7 kyr Template for Freshwater Forcing From the Laurentide Ice Sheet

    Jennings, A. E.; Andrews, J. T.

    2008-12-01

    A complex sequence of abrupt glacial advances and retreats punctuate the late phases of Laurentide Ice Sheet deglaciation. These episodes have been reconstructed from interpretation and mapping of glacial deposits on land and in marine basins proximal to the former ice margins in Hudson Strait, Hudson Bay, and the SE Baffin Island shelf. As these events likely produced pulses of freshwater discharge into the North Altantic, which may be responsible for rapid climate change, their timing and magnitude need to be understood. The timing of these events is well constrained by radiocarbon ages, but the ocean reservoir age in ice proximal areas is subject to very large uncertainties, making it difficult to determine calibrated ages for the glacial events so that they can be compared to other climate records. We suggest that the sequence of high detrital carbonate peaks in Holocene and Late Glacial sediments in the Cartwright Saddle of the Labrador shelf provides a template of the abrupt glacial events of the NE margin of the Laurentide Ice Sheet, particularly events that issued from Hudson Strait and Hudson Bay, but possibly including events in Baffin Bay. Once the Labrador Shelf was deglaciated and the local ice had retreated inland, the Cartwright Saddle was a distal trap for sediments released from Hudson Strait and other ice sheet outlets farther north as their sediments and meltwater were carried southwards by surface currents. Core MD99-2236 contains a sediment record beginning c. 13.9 cal ka. We assume a marine reservoir age for the Cartwright Saddle of 450 yrs, which is reasonable given the ice distal and oceanic position of the site. Carbonate was measured on average at a 30 yr time resolution. Carbonate values are elevated between 11.7 and 7 cal kyr BP, with six spikes exceeding 30 percent. Each spike corresponds to a light isotope spike in foraminifers, suggesting that each major spike is associated with a pulse of glacial meltwater. Elevated IRD counts

  16. Carbon dioxide sequestration induced mineral precipitation healing of fractured reservoir seals

    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.

  17. Pliocene Te Aute limestones, New Zealand : expanding concepts for cool-water shelf carbonates

    Nelson, C.S.; Winefield, P.R.; Hood, S.D.; Caron, V.; Pallentin, A.; Kamp, P.J.J.

    2003-01-01

    /or cementation to widely varying extents within any, or some combination of, the marine phreatic, burial, and meteoric diagenetic environments, including locally widespread development of meteoric cement sourced from aragonite dissolution. The message is that non-tropical shelf carbonates include a more diverse array of geological settings, of skeletal and mineralogical facies, and of diagenetic features than current sedimentary models mainly advocate. While several attributes positively distinguish tropical from non-tropical limestones, continued detailed documentation of the wide spectrum of shallow-marine carbonate deposits formed outside tropical regions remains an important challenge in carbonate sedimentology. (author). 68 refs., 12 figs., 2 tabs

  18. Estimates of Carbon Reservoirs in High-Altitude Wetlands in the Colombian Andes

    Enrique Javier Peña

    2009-10-01

    Full Text Available The observed increase in emission of greenhouse gases, with attendant effects on global warming, have raised interests in identifying sources and sinks of carbon in the environment. Terrestrial carbon (C sequestration involves capture of atmospheric C through photosynthesis and storage in biota, soil and wetlands. Particularly, wetland systems function primarily as long-term reservoirs for atmospheric carbon dioxide (CO2 and as sources of atmospheric methane (CH4. The objective of this study was to evaluate the patterns of carbon reservoirs in two high-altitude wetlands in the central Andean mountain of Colombia. Carbon cycle in both systems is related mainly with the plant biomass dynamics from the littoral zone. Thus, total organic carbon concentrate an average up to 329 kg of N ha-1 and 125 kg of P ha-1 every year vs only 17 kg N ha-1 and 6 kg P ha-1 in the water column of the limnetic zone in the wetland, evidencing spatial differences in carbon concentrations for these types of ecosystems. Results revealed that these systems participate in the balance and sequestration of carbon in the Colombian Andes.

  19. Identification of carbonate reservoirs based on well logging data for boreholes drilled using oil base muds

    Abdukhalikov, Ya.N; Serebrennikov, V.S.

    1979-01-01

    Experiment on carbonate reservoir identification according to well logging data for boreholes drilled using oil base muds is described. Pulse neutron-neutron logging (PNNL) was widely used at the territory of Pripyat' hole to solve the task. To evaluate volumetric clayiness of carbonate rocks the dependence of gamma-logging, that is data of gamma-logging against clayey rocks built for every hollow, is used. Quantitative estimation of clayiness of dense and clayey carbonate rocks-non-reservoirs is carried out on the basis of the data of neutron-gamma and acoustic logging. Porosity coefficient and lithological characteristic of rocks are also determined according to the data of acoustic and neutron gamma-logging

  20. SCREENING METHODS FOR SELECTION OF SURFACTANT FORMULATIONS FOR IOR FROM FRACTURED CARBONATE RESERVOIRS

    William A. Goddard III; Yongchun Tang; Patrick Shuler; Mario Blanco; Yongfu Wu; Seung Soon Jang

    2005-07-01

    This topical report presents details of the laboratory work performed to complete Task 1 of this project; developing rapid screening methods to assess surfactant performance for IOR (Improved Oil Recovery) from fractured carbonate reservoirs. The desired outcome is to identify surfactant formulations that increase the rate and amount of aqueous phase imbibition into oil-rich, oil-wet carbonate reservoir rock. Changing the wettability from oil-wet to water-wet is one key to enhancing this water-phase imbibition process that in turn recovers additional oil from the matrix portion of a carbonate reservoir. The common laboratory test to evaluate candidate surfactant formulations is to measure directly the aqueous imbibition rate and oil recovery from small outcrop or reservoir cores, but this procedure typically requires several weeks. Two methods are presented here for the rapid screening of candidate surfactant formulations for their potential IOR performance in carbonate reservoirs. One promising surfactant screening protocol is based on the ability of a surfactant solution to remove aged crude oil that coats a clear calcite crystal (Iceland Spar). Good surfactant candidate solutions remove the most oil the quickest from the chips, plus change the apparent contact angle of the remaining oil droplets on the surface that thereby indicate increased water-wetting. The other fast surfactant screening method is based on the flotation behavior of powdered calcite in water. In this test protocol, first the calcite power is pre-treated to make the surface oil-wet. The next step is to add the pre-treated powder to a test tube and add a candidate aqueous surfactant formulation; the greater the percentage of the calcite that now sinks to the bottom rather than floats, the more effective the surfactant is in changing the solids to become now preferentially water-wet. Results from the screening test generally are consistent with surfactant performance reported in the literature.

  1. CarbonSAFE Rocky Mountain Phase I : Seismic Characterization of the Navajo Reservoir, Buzzard Bench, Utah

    Haar, K. K.; Balch, R. S.; Lee, S. Y.

    2017-12-01

    The CarbonSAFE Rocky Mountain project team is in the initial phase of investigating the regulatory, financial and technical feasibility of commercial-scale CO2 capture and storage from two coal-fired power plants in the northwest region of the San Rafael Swell, Utah. The reservoir interval is the Jurassic Navajo Sandstone, an eolian dune deposit that at present serves as the salt water disposal reservoir for Ferron Sandstone coal-bed methane production in the Drunkards Wash field and Buzzard Bench area of central Utah. In the study area the Navajo sandstone is approximately 525 feet thick and is at an average depth of about 7000 feet below the surface. If sufficient porosity and permeability exist, reservoir depth and thickness would provide storage for up to 100,000 metric tonnes of CO2 per square mile, based on preliminary estimates. This reservoir has the potential to meet the DOE's requirement of having the ability to store at least 50 million metric tons of CO2 and fulfills the DOE's initiative to develop protocols for commercially sequestering carbon sourced from coal-fired power plants. A successful carbon storage project requires thorough structural and stratigraphic characterization of the reservoir, seal and faults, thereby allowing the creation of a comprehensive geologic model with subsequent simulations to evaluate CO2/brine migration and long-term effects. Target formation lithofacies and subfacies data gathered from outcrop mapping and laboratory analysis of core samples were developed into a geologic model. Synthetic seismic was modeled from this, allowing us to seismically characterize the lithofacies of the target formation. This seismic characterization data was then employed in the interpretation of 2D legacy lines which provided stratigraphic and structural control for more accurate model development of the northwest region of the San Rafael Swell. Developing baseline interpretations such as this are crucial toward long-term carbon storage

  2. Technical difficulties of logging while drilling in carbonate reservoirs and the countermeasures: A case study from the Sichuan Basin

    Shudong Zhang

    2015-12-01

    Full Text Available In the Sichuan Basin, carbonate reservoirs are characterized by deep burial depth and strong heterogeneity, so it is difficult to conduct structure steering, pore space reservoir tracking and trajectory control in the process of geosteering logging while drilling. In this paper, a series of corresponding techniques for structure, reservoir and formation tracking were proposed after analysis was conducted on multiple series of carbonate strata in terms of their geologic and logging response characteristics. And investigation was performed on the adaptabilities of the following logging technologies to geosteering while drilling, including gamma ray imaging while drilling, resistivity imaging while drilling, density imaging while drilling, gamma ray logging while drilling, resistivity logging while drilling, neutron logging while drilling and density logging while drilling. After while drilling information was thoroughly analyzed, the logging suites for four common types of complicated reservoirs (thin layered reservoirs, thick massive reservoirs, denuded karst reservoirs and shale gas reservoirs were optimized, and five logging combinations suitable for different formations and reservoirs were proposed, including gamma ray logging + porosity + resistivity imaging, gamma ray logging + resistivity imaging, gamma ray logging + porosity + resistivity logging, gamma ray imaging + resistivity logging, and gamma ray logging. Field application indicates that it is of great reference and application value to use this method for the first time to summarize logging while drilling combinations for different types of carbonate reservoirs.

  3. Pore Type Classification on Carbonate Reservoir in Offshore Sarawak using Rock Physics Model and Rock Digital Images

    Lubis, L A; Harith, Z Z T

    2014-01-01

    It has been recognized that carbonate reservoirs are one of the biggest sources of hydrocarbon. Clearly, the evaluation of these reservoirs is important and critical. For rigorous reservoir characterization and performance prediction from geophysical measurements, the exact interpretation of geophysical response of different carbonate pore types is crucial. Yet, the characterization of carbonate reservoir rocks is difficult due to their complex pore systems. The significant diagenesis process and complex depositional environment makes pore systems in carbonates far more complicated than in clastics. Therefore, it is difficult to establish rock physics model for carbonate rock type. In this paper, we evaluate the possible rock physics model of 20 core plugs of a Miocene carbonate platform in Central Luconia, Sarawak. The published laboratory data of this area were used as an input to create the carbonate rock physics models. The elastic properties were analyzed to examine the validity of an existing analytical carbonate rock physics model. We integrate the Xu-Payne Differential Effective Medium (DEM) Model and the elastic modulus which was simulated from a digital carbonate rock image using Finite Element Modeling. The results of this integration matched well for the separation of carbonate pore types and sonic P-wave velocity obtained from laboratory measurement. Thus, the results of this study show that the integration of rock digital image and theoretical rock physics might improve the elastic properties prediction and useful for more advance geophysical techniques (e.g. Seismic Inversion) of carbonate reservoir in Sarawak

  4. Oil recovery enhancement from fractured, low permeability reservoirs. [Carbonated Water

    Poston, S.W.

    1991-01-01

    The results of the investigative efforts for this jointly funded DOE-State of Texas research project achieved during the 1990-1991 year may be summarized as follows: Geological Characterization - Detailed maps of the development and hierarchical nature the fracture system exhibited by Austin Chalk outcrops were prepared. The results of these efforts were directly applied to the development of production decline type curves applicable to a dual-fracture-matrix flow system. Analysis of production records obtained from Austin Chalk operators illustrated the utility of these type curves to determine relative fracture/matrix contributions and extent. Well-log response in Austin Chalk wells has been shown to be a reliable indicator of organic maturity. Shear-wave splitting concepts were used to estimate fracture orientations from Vertical Seismic Profile, VSP data. Several programs were written to facilitate analysis of the data. The results of these efforts indicated fractures could be detected with VSP seismic methods.Development of the EOR Imbibition Process - Laboratory displacement as well as Magnetic Resonance Imaging, MRI and Computed Tomography, CT imaging studies have shown the carbonated water-imbibition displacement process significantly accelerates and increases recovery from oil saturated, low permeability rocks.Field Tests - Two operators amenable to conducting a carbonated water flood test on an Austin Chalk well have been identified. Feasibility studies are presently underway.

  5. Oil Recovery Enhancement from Fractured, Low Permeability Reservoirs. [Carbonated Water

    Poston, S. W.

    1991-01-01

    The results of the investigative efforts for this jointly funded DOE-State of Texas research project achieved during the 1990-1991 year may be summarized as follows: Geological Characterization - Detailed maps of the development and hierarchical nature the fracture system exhibited by Austin Chalk outcrops were prepared. The results of these efforts were directly applied to the development of production decline type curves applicable to a dual-fracture-matrix flow system. Analysis of production records obtained from Austin Chalk operators illustrated the utility of these type curves to determine relative fracture/matrix contributions and extent. Well-log response in Austin Chalk wells has been shown to be a reliable indicator of organic maturity. Shear-wave splitting concepts were used to estimate fracture orientations from Vertical Seismic Profile, VSP data. Several programs were written to facilitate analysis of the data. The results of these efforts indicated fractures could be detected with VSP seismic methods. Development of the EOR Imbibition Process - Laboratory displacement as well as Magnetic Resonance Imaging, MRI and Computed Tomography, CT imaging studies have shown the carbonated water-imbibition displacement process significantly accelerates and increases recovery from oil saturated, low permeability rocks. Field Tests - Two operators amenable to conducting a carbonated water flood test on an Austin Chalk well have been identified. Feasibility studies are presently underway.

  6. Validating predictions of evolving porosity and permeability in carbonate reservoir rocks exposed to CO2-brine

    Smith, M. M.; Hao, Y.; Carroll, S.

    2017-12-01

    Improving our ability to better forecast the extent and impact of changes in porosity and permeability due to CO2-brine-carbonate reservoir interactions should lower uncertainty in long-term geologic CO2 storage capacity estimates. We have developed a continuum-scale reactive transport model that simulates spatial and temporal changes to porosity, permeability, mineralogy, and fluid composition within carbonate rocks exposed to CO2 and brine at storage reservoir conditions. The model relies on two primary parameters to simulate brine-CO2-carbonate mineral reaction: kinetic rate constant(s), kmineral, for carbonate dissolution; and an exponential parameter, n, relating porosity change to resulting permeability. Experimental data collected from fifteen core-flooding experiments conducted on samples from the Weyburn (Saskatchewan, Canada) and Arbuckle (Kansas, USA) carbonate reservoirs were used to calibrate the reactive-transport model and constrain the useful range of k and n values. Here we present the results of our current efforts to validate this model and the use of these parameter values, by comparing predictions of extent and location of dissolution and the evolution of fluid permeability against our results from new core-flood experiments conducted on samples from the Duperow Formation (Montana, USA). Agreement between model predictions and experimental data increase our confidence that these parameter ranges need not be considered site-specific but may be applied (within reason) at various locations and reservoirs. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  7. Bacteria, carbon dioxide and methane measurements in the Cariaco Basin on the continental shelf of Venezuela, April 2001 - January 2002 (NODC Accession 0001078)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bacteria, carbon dioxide and methane measurements were collected using bottle casts in the Cariaco Basin on the continental shelf of Venezuela from 30 April 2001 to...

  8. Distribution and sources of organic carbon, nitrogen and their isotopic signatures in sediments from the Ayeyarwady (Irrawaddy) continental shelf, northern Andaman Sea

    Ramaswamy, V.; Gaye, B.; Shirodkar, P.V.; Rao, P.S.; Chivas, A.R.; Wheeler, D.; Thwin, S.

    Total organic carbon (TOC), total nitrogen (TN) and their delta sup(13) C and delta sup (15) N values were determined from 110 sediment samples from the Ayeyarwady (Irrawaddy) continental shelf, northern Andaman Sea to decipher the concentration...

  9. Flue gas injection into gas hydrate reservoirs for methane recovery and carbon dioxide sequestration

    Yang, Jinhai; Okwananke, Anthony; Tohidi, Bahman; Chuvilin, Evgeny; Maerle, Kirill; Istomin, Vladimir; Bukhanov, Boris; Cheremisin, Alexey

    2017-01-01

    Highlights: • Flue gas was injected for both methane recovery and carbon dioxide sequestration. • Kinetics of methane recovery and carbon dioxide sequestration was investigated. • Methane-rich gas mixtures can be produced inside methane hydrate stability zones. • Up to 70 mol% of carbon dioxide in the flue gas was sequestered as hydrates. - Abstract: Flue gas injection into methane hydrate-bearing sediments was experimentally investigated to explore the potential both for methane recovery from gas hydrate reservoirs and for direct capture and sequestration of carbon dioxide from flue gas as carbon dioxide hydrate. A simulated flue gas from coal-fired power plants composed of 14.6 mol% carbon dioxide and 85.4 mol% nitrogen was injected into a silica sand pack containing different saturations of methane hydrate. The experiments were conducted at typical gas hydrate reservoir conditions from 273.3 to 284.2 K and from 4.2 to 13.8 MPa. Results of the experiments show that injection of the flue gas leads to significant dissociation of the methane hydrate by shifting the methane hydrate stability zone, resulting in around 50 mol% methane in the vapour phase at the experimental conditions. Further depressurisation of the system to pressures well above the methane hydrate dissociation pressure generated methane-rich gas mixtures with up to 80 mol% methane. Meanwhile, carbon dioxide hydrate and carbon dioxide-mixed hydrates were formed while the methane hydrate was dissociating. Up to 70% of the carbon dioxide in the flue gas was converted into hydrates and retained in the silica sand pack.

  10. Stratigraphic framework of sediment-starved sand ridges on a mixed siliciclastic/carbonate inner shelf; west-central Florida

    Edwards, J.H.; Harrison, S.E.; Locker, S.D.; Hine, A.C.; Twichell, D.C.

    2003-01-01

    Seismic reflection profiles and vibracores have revealed that an inner shelf, sand-ridge field has developed over the past few thousand years situated on an elevated, broad bedrock terrace. This terrace extends seaward of a major headland associated with the modern barrier-island coastline of west-central Florida. The overall geologic setting is a low-energy, sediment-starved, mixed siliciclastic/carbonate inner continental shelf supporting a thin sedimentary veneer. This veneer is arranged in a series of subparallel, shore-oblique, and to a minor extent, shore-parallel sand ridges. Seven major facies are present beneath the ridges, including a basal Neogene limestone gravel facies and a blue-green clay facies indicative of dominantly authigenic sedimentation. A major sequence boundary separates these older units from Holocene age, organic-rich mud facies (marsh), which grades upward into a muddy sand facies (lagoon or shallow open shelf/seagrass meadows). Cores reveal that the muddy shelf facies is either in sharp contact or grades upward into a shelly sand facies (ravinement or sudden termination of seagrass meadows). The shelly sand facies grades upward to a mixed siliciclastic/carbonate facies, which forms the sand ridges themselves. This mixed siliciclastic/carbonate facies differs from the sediment on the beach and shoreface, suggesting insignificant sediment exchange between the offshore ridges and the modern coastline. Additionally, the lack of early Holocene, pre-ridge facies in the troughs between the ridges suggests that the ridges themselves do not migrate laterally extensively. Radiocarbon dating has indicated that these sand ridges can form relatively quickly (???1.3 ka) on relatively low-energy inner shelves once open-marine conditions are available, and that frequent, high-energy, storm-dominated conditions are not necessarily required. We suggest that the two inner shelf depositional models presented (open-shelf vs. migrating barrier-island) may

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

    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

  12. Modeling of carbonate reservoir variable secondary pore space based on CT images

    Nie, X.; Nie, S.; Zhang, J.; Zhang, C.; Zhang, Z.

    2017-12-01

    Digital core technology has brought convenience to us, and X-ray CT scanning is one of the most common way to obtain 3D digital cores. However, it can only provide the original information of the only samples being scanned, and we can't modify the porosity of the scanned cores. For numerical rock physical simulations, a series of cores with variable porosities are needed to determine the relationship between the physical properties and porosity. In carbonate rocks, the secondary pore space including dissolution pores, caves and natural fractures is the key reservoir space, which makes the study of carbonate secondary porosity very important. To achieve the variation of porosities in one rock sample, based on CT scanned digital cores, according to the physical and chemical properties of carbonate rocks, several mathematical methods are chosen to simulate the variation of secondary pore space. We use the erosion and dilation operations of mathematical morphology method to simulate the pore space changes of dissolution pores and caves. We also use the Fractional Brownian Motion model to generate natural fractures with different widths and angles in digital cores to simulate fractured carbonate rocks. The morphological opening-and-closing operations in mathematical morphology method are used to simulate distribution of fluid in the pore space. The established 3D digital core models with different secondary porosities and water saturation status can be used in the study of the physical property numerical simulations of carbonate reservoir rocks.

  13. Kinetics of carbonate dissolution in CO2-saturated aqueous system at reservoir conditions

    Peng, Cheng; Crawshaw, John P.; Maitland, Geoffrey; Trusler, J. P. Martin

    2014-05-01

    In recent years, carbon capture and storage (CCS) has emerged as a key technology for limiting anthropogenic CO2 emissions while allowing the continued utilisation of fossil fuels. The most promising geological storage sites are deep saline aquifers because the capacity, integrity and injection economics are most favourable, and the environmental impact can be minimal. Many rock-fluid chemical reactions are known to occur both during and after CO2 injection in saline aquifers. The importance of rock-fluid reactions in the (CO2 + H2O) system can be understood in terms of their impact on the integrity and stability of both the formation rocks and cap rocks. The chemical interactions between CO2-acidified brines and the reservoir minerals can influence the porosity and permeability of the formations, resulting in changes in the transport processes occurring during CO2 storage. Since carbonate minerals are abundant in sedimentary rocks, one of the requirements to safely implement CO2 storage in saline aquifers is to characterise the reactivity of carbonate minerals in aqueous solutions at reservoir conditions. In this work, we reported measurements of the intrinsic rate of carbonate dissolution in CO2-saturated water under high-temperature high-pressure reservoir conditions extending up to 373 K and 14 MPa. The rate of carbonate dissolution in CO2-free HCl(aq) was also measured at ambient pressure at temperatures up to 353 K. Various pure minerals and reservoir rocks were investigated in this study, including single-crystals of calcite and magnesite, and samples of dolomite, chalks and sandstones. A specially-designed batch reactor system, implementing the rotating disc technique, was used to obtain the intrinsic reaction rate at the solid/liquid interface, free of mass transfer effects. The effective area and mineralogy of the exposed surface was determined by a combination of surface characterisation techniques including XRD, SEM, EDX and optical microscopy. The

  14. Prediction of abrupt reservoir compaction and surface subsidence due to pore collapse in carbonates

    Smits, R.M.M.; de Waal, A.; van Kooten, J.F.C.

    1986-01-01

    A new procedure has been developed to predict the abrupt in-situ compaction and the associated surface subsidence above high-porosity carbonate fields showing pore collapse. The approach is based on an extensive laboratory compaction study in which the effects of carbonate type, porosity, core preparation, pore saturant, horizontal to vertical stress ratio and loading rate on the pore collapse behaviour were investigated. For each carbonate type a trendline was established describing the relationship between the porosity after collapse and the vertical effective stress. This trendline concept, in combination with existing subsidence models, enables reservoir compaction and surface subsidence to be predicted on the basis of wireline porosity logs. Static and dynamic elastic constants were found to be uncorrelated during pore collapse. The position of the trendline depends strongly on carbonate type, pore saturant, loading rate and stress ratio. Therefore procedures are given to derive the correct in-situ trendline from laboratory compaction experiments.

  15. Prediction of abrupt reservoir compaction and surface subsidence caused by pore collapse in carbonates

    Smits, R.M.M.; De Waal, J.A.; Van Kootan, J.F.C.

    1988-06-01

    A new procedure has been developed to predict the abrupt in-situ compaction and the associated surface subsidence above high-porosity carbonate fields that show pore collapse. The approach is based on an extensive laboratory compaction study in which the effects of carbonate type, porosity, core preparation, pore saturant, horizontal/vertical stress ratio, and loading rate on pore-collapse behavior were investigated. For a number of carbonate types, a trendline was established that describes the relationship between the porosity after collapse and the vertical effective stress. This trendline concept, in combination with existing subsidence models, enables reservoir compaction and surface subsidence to be predicted on the basis of wireline porosity logs. Static and dynamic elastic constants were found to be uncorrelated during pore collapse. The position of the trendline depends strongly on carbonate type, pore saturant, loading rate, and stress ratio. Therefore, procedures are given to derive the correct in-situ trendline from laboratory compaction experiments.

  16. Criteria for identification of carbonate reservoirs according to well logging data (carboniferous deposits of Astrakhan' vault taken as an example)

    Makarova, A.N.; Mitalev, I.A.

    1979-01-01

    Described are the criteria for identification of carbonate reservoirs according to well logging data (carboniferous deposits of Astrakhan' vault taken as an example). According to gamma logging and cavitymetry data clay areas (decreased readings of neutron-gamma logging opposite dense rocks) are distinguished in a well log. ''Reservoir-nonreserVoir'' boundary is relatively drawn on the basis of the relation between neutron-gamma logaing indications and average general porosity of carbonate rocks determined by accoustic and neutron gamma logging

  17. Size distribution and carbonate content of the sediments of the western shelf of India

    Nair, R.R.; Pylee, A.

    %). (2) The outer shelf (approximately 20 to 70 fms) is a zone of relict sediments, having relatively low rates of sedimentation and composed of fine to medium sands. Occasional patches of coarse iron stained sands and pebbles are also present...

  18. Thermal regime of the deep carbonate reservoir of the Po Plain (Italy)

    Pasquale, V.; Chiozzi, P.; Verdoya, M.

    2012-04-01

    Italy is one of the most important countries in the world with regard to high-medium enthalpy geothermal resources, a large part of which is already extracted at relatively low cost. High temperatures at shallow to medium depth occur within a wide belt, several hundred kilometre long, west of the Apennines mountain chain. This belt, affected by recent lithosphere extension, includes several geothermal fields, which are largely exploited for electricity generation. Between the Alps and Apennines ranges, the deeper aquifer, occurring in carbonate rocks of the Po Plain, can host medium enthalpy fluids, which are exploited for district heating. Such a general picture of the available geothermal resources has been well established through several geophysical investigations and drillings. Nevertheless, additional studies are necessary to evaluate future developments, especially with reference to the deep carbonate aquifer of the Po Plain. In this paper, we focus on the eastern sector of the plain and try to gain a better understanding of the thermal regime by using synergically geothermal methodologies and geological information. The analysis of the temperatures recorded to about 6 km depth in hydrocarbon wells supplies basic constraints to outline the thermal regime of the sedimentary basin and to investigate the occurrence and importance of hydrothermal processes in the carbonate layer. After correction for drilling disturbance, temperatures were analysed, together with geological information, through an inversion technique based on a laterally constant thermal gradient model. The inferred thermal gradient changes with depth; it is quite low within the carbonate layer, while is larger in the overlying, practically impermeable formations. As the thermal conductivity variation does not justify such a thermal gradient difference, the vertical change can be interpreted as due to convective processes occurring in the carbonate layer, acting as thermal reservoir. The

  19. Characterization of commercial off-the shelf regenerable sorbent to scrub carbon dioxide in a portable life support system

    Arai, Tatsuya; Fricker, John

    2018-06-01

    A resin bead Mitsubishi DIAION™ CR20 was identified and characterized as a first commercial off-the shelf regenerable carbon dioxide (CO2) sorbent candidate for space life support system applications at room temperature. The CO2 adsorption rates and capacities of CR20 at varying CO2 partial pressures were obtained. The data were used to numerically simulate CO2 adsorption by a swingbed, a pair of two sorbent beds that alternately adsorb and desorb CO2 in a space suit portable life support system (PLSS). The result demonstrated that a reasonable volume of CR20 would be able to continuously adsorb CO2 with bed-swing interval of 4 min at 300-W metabolic rate, and that commercial off-the shelf CR20 would have similar performance of CO2 adsorption to the proprietary swingbed sorbent SA9T for PLSS applications.

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

    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

  1. Total porosity of carbonate reservoir rocks by X-ray microtomography in two different spatial resolutions

    Nagata, Rodrigo; Appoloni, Carlos R.; Marques, Leonardo C.; Fernandes, Celso P.

    2011-01-01

    Carbonate reservoir rocks contain more than 50% of world's petroleum. To know carbonate rocks' structural properties is quite important to petroleum extraction. One of their main structural properties is the total porosity, which shows the rock's capacity to stock petroleum. In recent years, the X-ray microtomography had been used to analyze the structural parameters of reservoir rocks. Such nondestructive technique generates images of the samples' internal structure, allowing the evaluation of its properties. The spatial resolution is a measurement parameter that indicates the smallest structure size observable in a sample. It is possible to measure one sample using two or more different spatial resolutions in order to evaluate the samples' pore scale. In this work, two samples of the same sort of carbonate rock were measured, and in each measurement a different spatial resolution (17 μm and 7 μm) was applied. The obtained results showed that with the better resolution it was possible to measure 8% more pores than with the poorer resolution. Such difference provides us with good expectations about such approach to study the pore scale of carbonate rocks. (author)

  2. INTEGRATED OUTCROP AND SUBSURFACE STUDIES OF THE INTERWELL ENVIRONMENT OF CARBONATE RESERVOIRS: CLEAR FORK (LEONARDIAN-AGE) RESERVOIRS, WEST TEXAS AND NEW MEXICO

    F. Jerry Lucia

    2002-01-31

    This is the final report of the project ''Integrated Outcrop and Subsurface Studies of the Interwell Environment of Carbonate Reservoirs: Clear Fork (Leonardian-Age) Reservoirs, West Texas and New Mexico'', Department of Energy contract no. DE-AC26-98BC15105 and is the third in a series of similar projects funded jointly by the U.S. Department of Energy and The University of Texas at Austin, Bureau of Economic Geology, Reservoir Characterization Research Laboratory for Carbonates. All three projects focus on the integration of outcrop and subsurface data for the purpose of developing improved methods for modeling petrophysical properties in the interwell environment. The first project, funded by contract no. DE-AC22-89BC14470, was a study of San Andres outcrops in the Algerita Escarpment, Guadalupe Mountains, Texas and New Mexico, and the Seminole San Andres reservoir, Permian Basin. This study established the basic concepts for constructing a reservoir model using sequence-stratigraphic principles and rock-fabric, petrophysical relationships. The second project, funded by contract no. DE-AC22-93BC14895, was a study of Grayburg outcrops in the Brokeoff Mountains, New Mexico, and the South Cowden Grayburg reservoir, Permian Basin. This study developed a sequence-stratigraphic succession for the Grayburg and improved methods for locating remaining hydrocarbons in carbonate ramp reservoirs. The current study is of the Clear Fork Group in Apache Canyon, Sierra Diablo Mountains, West Texas, and the South Wasson Clear Fork reservoir, Permian Basin. The focus was on scales of heterogeneity, imaging high- and low-permeability layers, and the impact of fractures on reservoir performance. In this study (1) the Clear Fork cycle stratigraphy is defined, (2) important scales of petrophysical variability are confirmed, (3) a unique rock-fabric, petrophysical relationship is defined, (4) a porosity method for correlating high-frequency cycles and defining rock

  3. Quantification of dissolved organic carbon (DOC) storage in lakes and reservoirs of mainland China.

    Song, Kaishan; Wen, Zhidan; Shang, Yingxing; Yang, Hong; Lyu, Lili; Liu, Ge; Fang, Chong; Du, Jia; Zhao, Ying

    2018-04-04

    As a major fraction of carbon in inland waters, dissolved organic carbon (DOC) plays a crucial role in carbon cycling on a global scale. However, the quantity of DOC stored in lakes and reservoirs was not clear to date. In an attempt to examine the factors that determine the DOC storage in lakes and reservoirs across China, we assembled a large database (measured 367 lakes, and meta-analyzed 102 lakes from five limnetic regions; measured 144 reservoirs, and meta-analyzed 272 reservoirs from 31 provincial units) of DOC concentrations and water storages for lakes and reservoirs that are used to determine DOC storage in static inland waters. We found that DOC concentrations in saline waters (Mean/median ± S.D: 50.5/30.0 ± 55.97 mg/L) are much higher than those in fresh waters (8.1/5.9 ± 6.8 mg/L), while lake DOC concentrations (25.9/11.5 ± 42.04 mg/L) are much higher than those in reservoirs (5.0/3.8 ± 4.5 mg/L). In terms of lake water volume and DOC storage, the Tibet-Qinghai lake region has the largest water volume (552.8 km 3 ), 92% of which is saline waters, thus the largest DOC (13.39 Tg) is stored in these alpine lake region; followed by the Mengxin lake region, having a water volume of 99.4 km 3 in which 1.75 Tg DOC was stored. Compared to Mengxin lake region, almost the same amount of water was stored in East China lake region (91.9 km 3 ), however, much less DOC was stored in this region (0.43 Tg) due to the lower DOC concentration (Ave: 3.45 ± 2.68 mg/L). According to our investigation, Yungui and Northeast lake regions had water storages of 32.14 km 3 and 19.44 km 3 respectively, but relatively less DOC was stored in Yungui (0.13 Tg) than in Northeast lake region (0.19 Tg). Due to low DOC concentration in reservoirs, especially these large reservoirs having lower DOC concentration (V > 1.0 km 3 : 2.31 ± 1.48 mg/L), only 1.54 Tg was stored in a 485.1 km 3 volume of water contained

  4. Integrated Modeling and Carbonate Reservoir Analysis, Upper Jurassic Smackover Formation, Fishpond Field, Southwest Alabama

    Owen, Alexander Emory

    This field case study focuses on Upper Jurassic (Oxfordian) Smackover hydrocarbon reservoir characterization, modeling and evaluation at Fishpond Field, Escambia County, Alabama, eastern Gulf Coastal Plain of North America. The field is located in the Conecuh Embayment area, south of the Little Cedar Creek Field in Conecuh County and east of Appleton Field in Escambia County. In the Conecuh Embayment, Smackover microbial buildups commonly developed on Paleozoic basement paleohighs in an inner to middle carbonate ramp setting. The microbial and associated facies identified in Fishpond Field are: (F-1) peloidal wackestone, (F-2) peloidal packstone, (F-3) peloidal grainstone, (F-4) peloidal grainstone/packstone, (F-5) microbially-influenced wackestone, (F-6) microbially-influenced packstone, (F-7) microbial boundstone, (F-8) oolitic grainstone, (F-9) shale, and (F-10) dolomitized wackestone/packstone. The Smackover section consists of an alternation of carbonate facies, including F-1 through F-8. The repetitive vertical trend in facies indicates variations in depositional conditions in the area as a result of changes in water depth, energy conditions, salinity, and/or water chemistry due to temporal variations or changes in relative sea level. Accommodation for sediment accumulation also was produced by a change in base level due to differential movement of basement rocks as a result of faulting and/or subsidence due to burial compaction and extension. These changes in base level contributed to the development of a microbial buildup that ranges between 130-165 ft in thickness. The Fishpond Field carbonate reservoir includes a lower microbial buildup interval, a middle grainstone/packstone interval and an upper microbial buildup interval. The Fishpond Field has sedimentary and petroleum system characteristics similar to the neighboring Appleton and Little Cedar Creek Fields, but also has distinct differences from these Smackover fields. The characteristics of the

  5. Discovery of Widespread Biogenic Methane Emissions and Authigenic Carbonate Mound-like Structures at the Aquitaine Shelf (Bay of Biscay)

    Dupré, S.; Loubrieu, B.; Scalabrin, C.; Ehrhold, A.; Gautier, E.; Ruffine, L.; Pierre, C.; Battani, A.; Le Bouffant, N.; Berger, L.

    2014-12-01

    Fishery acoustic surveys conducted in the Bay of Biscay (1998-2012) and dedicated to monitoring and predicting pelagic ecosystem evolution reveal numerous active seeps on the Aquitaine Shelf, east of the shelf break (Dupré et al. 2014). Seafloor and water column acoustic investigation with the use of ship-borne multibeam echosounder in 2013 (Gazcogne1 marine expedition) confirmed the presence of numerous (> 3000) persistent and widespread gas emission sites at water depths ranging from ~140 to 180 m. These fluid emissions are associated at the seafloor with high backscatter subcircular small-scale mounds, on average less than 2 m high and a few meters in diameter. Near-bottom visual observations and samplings were conducted with the ROV (Remotely Operated Vehicle) Victor (Gazcogne2 expedition). The whole mounds cover an area of ~200 km2 of the seabed, and are by-products of gas seepage, i.e. methane-derived authigenic carbonates. The spatial distribution of the seeps and related structures, based on water column acoustic gas flares and high backscatter seabed patches, appears to be relatively broad, with a North-South extension of ~80 km across the Parentis Basin and the Landes High, and a West-East extension along a few kilometers wide on the shelf, up to 8 km. Gas bubbles sampled at in situ conditions are principally composed of biogenic methane, possibly originated from Late Pleistocene deposits. The volume of methane emitted into the water column is abundant i) with an average gas flux varying locally from 0.035 to 0.37 Ln/min and ii) with regard to the time needed for the precipitation of the authigenic carbonates identified both at the seabed and in the upper most sedimentary column. The GAZCOGNE study is co-funded by TOTAL and IFREMER as part of the PAMELA (Passive Margin Exploration Laboratories) scientific project. ReferenceDupré, S., Berger, L., Le Bouffant, N., Scalabrin, C., and Bourillet, J.-F., 2014. Fluid emissions at the Aquitaine Shelf (Bay of

  6. Utilization of buffered vinegar to increase the shelf life of chicken retail cuts packaged in carbon dioxide.

    Desai, Monil A; Kurve, Vikram; Smith, Brian S; Campano, Stephen G; Soni, Kamlesh; Schilling, M Wes

    2014-07-01

    Poultry processors commonly place whole parts of broilers in plastic packages and seal them in an atmosphere of 100% carbon dioxide before shipping them to food service and retail customers. This practice extends the shelf life of retail cuts to approximately 12 d under refrigerated conditions. The objective of this study was to determine the antimicrobial efficacy of vinegar for growth inhibition of mesophilic and lactic acid bacterial counts and enhancement of shelf life in CO2-packaged refrigerated chicken thigh samples. Meat quality, sensory differences, and microbial enumeration were evaluated for chicken thighs that were sprayed with 0, 0.5, or 1.0% vinegar. No differences were observed (P > 0.05) among treatments (control vs. 0.5 and 1.0% vinegar-treated chicken thighs) with respect to pH and Commission Internationale d'Eclairage L*a*b*for both chicken skin and the meat tissue. The difference from the control test indicated that trained panelists were not able to detect a difference (P > 0.05) in flavor between the chicken thigh treatments. The mesophilic and Lactobacillus bacterial counts were enumerated after 0, 4, 8, 12, 16, and 20 d of storage. The mesophilic bacterial load for the 1.0% vinegar treatment was less than all other treatments after 8, 12, 16, and 20 d of storage, whereas the 0.5% vinegar treatment had lower bacterial counts at d 12 than both controls and had an approximate shelf life of 16 d. For lactic acid bacteria, the vinegar 1.0% treatment had lower counts than the control treatments at d 12 and 16. The results from the study indicate that a combination of 1.0% vinegar with CO2 packaging can extend the shelf life from 12 to 20 d for chicken retail cuts without negatively affecting the quality and sensory properties of the broiler meat. © 2014 Poultry Science Association Inc.

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

    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

  8. Why is the South Orkney Island shelf (the world's first high seas marine protected area) a carbon immobilization hotspot?

    Barnes, David K A; Ireland, Louise; Hogg, Oliver T; Morley, Simon; Enderlein, Peter; Sands, Chester J

    2016-03-01

    The Southern Ocean archipelago, the South Orkney Islands (SOI), became the world's first entirely high seas marine protected area (MPA) in 2010. The SOI continental shelf (~44 000 km(2) ), was less than half covered by grounded ice sheet during glaciations, is biologically rich and a key area of both sea surface warming and sea-ice losses. Little was known of the carbon cycle there, but recent work showed it was a very important site of carbon immobilization (net annual carbon accumulation) by benthos, one of the few demonstrable negative feedbacks to climate change. Carbon immobilization by SOI bryozoans was higher, per species, unit area and ice-free day, than anywhere-else polar. Here, we investigate why carbon immobilization has been so high at SOI, and whether this is due to high density, longevity or high annual production in six study species of bryozoans (benthic suspension feeders). We compared benthic carbon immobilization across major regions around West Antarctica with sea-ice and primary production, from remotely sensed and directly sampled sources. Lowest carbon immobilization was at the northernmost study regions (South Georgia) and southernmost Amundsen Sea. However, data standardized for age and density showed that only SOI was anomalous (high). High immobilization at SOI was due to very high annual production of bryozoans (rather than high densities or longevity), which were 2x, 3x and 5x higher than on the Bellingshausen, South Georgia and Amundsen shelves, respectively. We found that carbon immobilization correlated to the duration (but not peak or integrated biomass) of phytoplankton blooms, both in directly sampled, local scale data and across regions using remote-sensed data. The long bloom at SOI seems to drive considerable carbon immobilization, but sea-ice losses across West Antarctica mean that significant carbon sinks and negative feedbacks to climate change could also develop in the Bellingshausen and Amundsen seas. © 2015 John Wiley

  9. Experimental and numerical modeling of sulfur plugging in a carbonate oil reservoir

    Al-Awadhy, F. [ADMA-OPCO, Abudhabi (United Arab Emirates); Kocabas, I.; Abou-Kassem, J.H. [UAE University, Al Ain (United Arab Emirates); Islam, M.R. [Dalhousie University, Halifax, NS (United States)

    2005-01-15

    Many oil and gas reservoirs in the United Arab Emirates produce large amounts of sour gas, mainly in the form of hydrogen sulfide. In addition to creating problems in the production line, wellbore damage is often reported due to the precipitation of elemental sulfur in the vicinity of the wellbore. While there have been several studies performed on the role of solid deposition in a gas reservoir, the role of sulfur deposition in oil reservoirs has not been investigated. This article presents experimental results along with a comprehensive wellbore model that predicts sulfur precipitation as well as plugging. The experiments were conducted in a core (linear) system. Both analytical and numerical modelings were performed in a linear coordinate system. Data for the numerical model was obtained from both test tube and coreflood experiments. By using a phenomenological model, the wellbore plugging was modeled with an excellent match (with experimental results). The crude oil was de-asphalted prior to conducting the experiment in order to isolate the effect of asphaltene plugging. A series of coreflood tests was carried out to observe sulfur precipitation and plugging in a carbonate rock. Significant plugging was observed and was found to be dependent on flow rate and initial sulfur concentration. This information was used in the phenomenological model and can be incorporated in the wellbore numerical model. (author)

  10. Picophytoplankton and carbon cycle on the northeastern shelf of the Gulf of Cádiz (SW Iberian Peninsula

    Mariana Ribas-Ribas

    2013-01-01

    Full Text Available Four surveys (Jun’06 and Nov’06; Feb’07 and May’07 were carried out on the northeastern shelf of the Gulf of Cádiz (southwest Iberian Peninsula to relate the spatio-temporal distribution of the carbon cycle parameters (dissolved inorganic carbon and dissolved organic carbon to picophytoplankton biomass and community composition. In addition, the net ecosystem production and the picophytoplankton contribution to the air-sea CO2 exchange process were investigated. The results showed that chlorophyll-a, carbon cycle parameters and picophytoplankton composition showed large seasonality, and the Guadalquivir Estuary plays an important role in the contribution of nutrient and suspended particular material over the year. Regarding picophytoplankton composition, the flow cytometry analysis demonstrated that Prochlorococcus and Synechococcus were the main populations in the studied area and their temporal and spatial distributions were complementary: the Prochlorococcus population showed its maximum concentration in May’07 and Jun’06 and in the surface oceanic water, whereas the Synechococcus population was at its maximum during Feb’07 and Nov’06, and off the Guadalquivir Estuary and Bay of Cádiz. In addition, a relationship between the studied parameters and the fugacity of CO2 was also observed, suggesting that primary production is an important factor in the regulation of this parameter in the studied area. The calculated carbon budget showed that the area acts as a carbon sink on an annual basis.

  11. Petroleum potential of dysaerobic carbonate source rocks in an intra-shelf basin: the Lower Cretaceous of Provence, France

    Machhour, L.; Oudin, J.-L.; Lambert, B.; Lapointe, P. [TOTAL, Centre Scientifique et Technique, Saint-Remy-les-Chevreuse, 78 (France); Masse, J.-P. [Universite de Provence, Centre de Sedimentologie-Paleontologie, Marseille, 13 (France)

    1998-05-01

    Barremian-Aptian Carbonate sediments in southern Provence belong to a drowning sequence within an intra-shelf basin and display organic-carbon-rich horizons corresponding to the demise of a rudists platform system and the onset of dysaerobic conditions. These horizons depart from the classical anoxic model accepted for most marine organic-carbon-rich deposits. They have a rich and diverse fauna documenting nutrient-rich waters with low oxygen content - an environment in which organic matter is preserved from both biological and chemical degradation. Sedimentological, geochemical and palaeoecological investigations suggest that the organic-carbon-rich carbonates reflect dysaerobic conditions favourable for organic matter preservation, the amount of dissolved oxygen being lower than the geochemical threshold for organic matter decay. These organic-carbon-rich sediments are the result of high sea surface productivity and sea bottom conditions favouring preservation. The kerogen is mainly amorphous sapropelic organic matter, essentially algal, with a high hydrogen index and is of marine origin, deposited during high sea-level. (Author)

  12. High-Performance Modeling of Carbon Dioxide Sequestration by Coupling Reservoir Simulation and Molecular Dynamics

    Bao, Kai

    2015-10-26

    The present work describes a parallel computational framework for carbon dioxide (CO2) sequestration simulation by coupling reservoir simulation and molecular dynamics (MD) on massively parallel high-performance-computing (HPC) systems. In this framework, a parallel reservoir simulator, reservoir-simulation toolbox (RST), solves the flow and transport equations that describe the subsurface flow behavior, whereas the MD simulations are performed to provide the required physical parameters. Technologies from several different fields are used to make this novel coupled system work efficiently. One of the major applications of the framework is the modeling of large-scale CO2 sequestration for long-term storage in subsurface geological formations, such as depleted oil and gas reservoirs and deep saline aquifers, which has been proposed as one of the few attractive and practical solutions to reduce CO2 emissions and address the global-warming threat. Fine grids and accurate prediction of the properties of fluid mixtures under geological conditions are essential for accurate simulations. In this work, CO2 sequestration is presented as a first example for coupling reservoir simulation and MD, although the framework can be extended naturally to the full multiphase multicomponent compositional flow simulation to handle more complicated physical processes in the future. Accuracy and scalability analysis are performed on an IBM BlueGene/P and on an IBM BlueGene/Q, the latest IBM supercomputer. Results show good accuracy of our MD simulations compared with published data, and good scalability is observed with the massively parallel HPC systems. The performance and capacity of the proposed framework are well-demonstrated with several experiments with hundreds of millions to one billion cells. To the best of our knowledge, the present work represents the first attempt to couple reservoir simulation and molecular simulation for large-scale modeling. Because of the complexity of

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

    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.

  14. Facies analysis of an Upper Jurassic carbonate platform for geothermal reservoir characterization

    von Hartmann, Hartwig; Buness, Hermann; Dussel, Michael

    2017-04-01

    The Upper Jurassic Carbonate platform in Southern Germany is an important aquifer for the production of geothermal energy. Several successful projects were realized during the last years. 3D-seismic surveying has been established as a standard method for reservoir analysis and the definition of well paths. A project funded by the federal ministry of economic affairs and energy (BMWi) started in 2015 is a milestone for an exclusively regenerative heat energy supply of Munich. A 3D-seismic survey of 170 square kilometer was acquired and a scientific program was established to analyze the facies distribution within the area (http://www.liag-hannover.de/en/fsp/ge/geoparamol.html). Targets are primarily fault zones where one expect higher flow rates than within the undisturbed carbonate sediments. However, since a dense net of geothermal plants and wells will not always find appropriate fault areas, the reservoir properties should be analyzed in more detail, e.g. changing the viewpoint to karst features and facies distribution. Actual facies interpretation concepts are based on the alternation of massif and layered carbonates. Because of successive erosion of the ancient land surfaces, the interpretation of reefs, being an important target, is often difficult. We found that seismic sequence stratigraphy can explain the distribution of seismic pattern and improves the analysis of different facies. We supported this method by applying wavelet transformation of seismic data. The splitting of the seismic signal into successive parts of different bandwidths, especially the frequency content of the seismic signal, changed by tuning or dispersion, is extracted. The combination of different frequencies reveals a partition of the platform laterally as well as vertically. A cluster analysis of the wavelet coefficients further improves this picture. The interpretation shows a division into ramp, inner platform and trough, which were shifted locally and overprinted in time by other

  15. Sources of organic carbon in the Portuguese continental shelf sediments during the Holocene period

    Burdloff, D.; Araujo, M.F.; Jouanneau, J.-M.; Mendes, I.; Monge Soares, A.M.; Dias, J.M.A.

    2008-01-01

    Organic C (OC) and total N (TN) concentrations, and stable isotope ratios (δ 13 C) in muddy deposit sediments of the Northern and Southern Portuguese continental shelf were used to identify sources of fine-sized organic matter ( 13 C ranging, respectively, from 8.5 to 21 and from -22.4 per mille to -27 per mille ). Intense supplies to the Guadiana continental shelf of fine terrigenous particles during the Younger-Dryas Event are closely linked with higher OC/TN values and lower δ 13 C ratios. During the postglacial transgression phase, an increasing contribution of marine supplies (up to 80%) occurred. Higher δ 13 C (up to -22.4 per mille ) values and low OC/TN ratios (down to 8.5) are found as the sea level approaches the current one. The Upper Holocene records emphasize the return to enhanced terrestrial supplies except for the Little Climatic Optimum between the 11th and 15th centuries AD. This climatic event is especially obvious in the three cores as a return to marine production and a decrease in terrestrial sediment supply to the continental shelf. The return to a cooling event, the Little Ice Age, between the 15th and 19th centuries AD, is mirrored by decreased terrigenous supplies in core KSGX 57. Gradually increasing sedimentation in estuaries, as well as formation of coastal dune fields, have been hypothesized on the basis of increasing δ 13 C and decreasing OC, TN and OC/TN values

  16. Some open issues in the analysis of the storage and migration properties of fractured carbonate reservoirs

    Agosta, Fabrizio

    2017-04-01

    Underground CO2 storage in depleted hydrocarbon reservoirs may become a common practice in the future to lower the concentration of greenhouse gases in the atmosphere. Results from the first experiments conducted in carbonate rocks, for instance the Lacq integrated CCS Pilot site, SW France, are quite exciting. All monitored parameters, such as the CO2 concentration at well sites, well pressures, cap rock integrity and environmental indicators show the long-term integrity of this type of geological reservoirs. Other positive news arise from the OXY-CFB-300 Compostilla Project, NW Spain, where most of the injected CO2 dissolved into the formation brines, suggesting the long-term security of this method. However, in both cases, the CO2- rich fluids partially dissolved the carbonate minerals during their migration through the fractured reservoir, modifying the overall pore volume and pressure regimes. These results support the growing need for a better understanding of the mechanical behavior of carbonate rocks over geological time of scales. In fact, it is well known that carbonates exhibit a variety of deformation mechanisms depending upon many intrinsic factors such as composition, texture, connected pore volume, and nature of the primary heterogeneities. Commonly, tight carbonates are prone to opening-mode and/or pressure solution deformation. The interplay between these two mechanisms likely affects the petrophysical properties of the fault damage zones, which form potential sites for CO2 storage due to their high values of both connected porosity and permeability. On the contrary, cataclastic deformation produces fault rocks that often form localized fluid barriers for cross-fault fluid flow. Nowadays, questions on the conditions of sealing/leakage of carbonate fault rocks are still open. In particular, the relative role played by bulk crushing, chipping, cementation, and pressure solution on connected porosity of carbonate fault rocks during structural

  17. Mineral Dissolution and Precipitation due to Carbon Dioxide-Water-Rock Interactions: The Significance of Accessory Minerals in Carbonate Reservoirs (Invited)

    Kaszuba, J. P.; Marcon, V.; Chopping, C.

    2013-12-01

    Accessory minerals in carbonate reservoirs, and in the caprocks that seal these reservoirs, can provide insight into multiphase fluid (CO2 + H2O)-rock interactions and the behavior of CO2 that resides in these water-rock systems. Our program integrates field data, hydrothermal experiments, and geochemical modeling to evaluate CO2-water-rock reactions and processes in a variety of carbonate reservoirs in the Rocky Mountain region of the US. These studies provide insights into a wide range of geologic environments, including natural CO2 reservoirs, geologic carbon sequestration, engineered geothermal systems, enhanced oil and gas recovery, and unconventional hydrocarbon resources. One suite of experiments evaluates the Madison Limestone on the Moxa Arch, Southwest Wyoming, a sulfur-rich natural CO2 reservoir. Mineral textures and geochemical features developed in the experiments suggest that carbonate minerals which constitute the natural reservoir will initially dissolve in response to emplacement of CO2. Euhedral, bladed anhydrite concomitantly precipitates in response to injected CO2. Analogous anhydrite is observed in drill core, suggesting that secondary anhydrite in the natural reservoir may be related to emplacement of CO2 into the Madison Limestone. Carbonate minerals ultimately re-precipitate, and anhydrite dissolves, as the rock buffers the acidity and reasserts geochemical control. Another suite of experiments emulates injection of CO2 for enhanced oil recovery in the Desert Creek Limestone (Paradox Formation), Paradox Basin, Southeast Utah. Euhedral iron oxyhydroxides (hematite) precipitate at pH 4.5 to 5 and low Eh (approximately -0.1 V) as a consequence of water-rock reaction. Injection of CO2 decreases pH to approximately 3.5 and increases Eh by approximately 0.1 V, yielding secondary mineralization of euhedral pyrite instead of iron oxyhydroxides. Carbonate minerals also dissolve and ultimately re-precipitate, as determined by experiments in the

  18. Kinetics of carbonate mineral dissolution in CO2-acidified brines at storage reservoir conditions.

    Peng, Cheng; Anabaraonye, Benaiah U; Crawshaw, John P; Maitland, Geoffrey C; Trusler, J P Martin

    2016-10-20

    We report experimental measurements of the dissolution rate of several carbonate minerals in CO 2 -saturated water or brine at temperatures between 323 K and 373 K and at pressures up to 15 MPa. The dissolution kinetics of pure calcite were studied in CO 2 -saturated NaCl brines with molalities of up to 5 mol kg -1 . The results of these experiments were found to depend only weakly on the brine molality and to conform reasonably well with a kinetic model involving two parallel first-order reactions: one involving reactions with protons and the other involving reaction with carbonic acid. The dissolution rates of dolomite and magnesite were studied in both aqueous HCl solution and in CO 2 -saturated water. For these minerals, the dissolution rates could be explained by a simpler kinetic model involving only direct reaction between protons and the mineral surface. Finally, the rates of dissolution of two carbonate-reservoir analogue minerals (Ketton limestone and North-Sea chalk) in CO 2 -saturated water were found to follow the same kinetics as found for pure calcite. Vertical scanning interferometry was used to study the surface morphology of unreacted and reacted samples. The results of the present study may find application in reactive-flow simulations of CO 2 -injection into carbonate-mineral saline aquifers.

  19. Integrated Sedimentological Approach to Assess Reservoir Quality and Architecture of Khuff Carbonates: Outcrop Analog, Central Saudi Arabia

    Osman, Mutsim; Abdullatif, Osman

    2017-04-01

    The Permian to Triassic Khuff carbonate reservoirs (and equivalents) in the Middle East are estimated to contain about 38.4% of the world's natural gas reserves. Excellent exposed outcrops in central Saudi Arabia provide good outcrop equivalents to subsurface Khuff reservoirs. This study conduct high resolution outcrop scale investigations on an analog reservoir for upper Khartam of Khuff Formation. The main objective is to reconstruct litho- and chemo- stratigraphic outcrop analog model that may serve to characterize reservoir high resolution (interwell) heterogeneity, continuity and architecture. Given the fact of the limitation of subsurface data and toolsin capturing interwell reservoir heterogeneity, which in turn increases the value of this study.The methods applied integrate sedimentological, stratigraphic petrographic, petrophysical data and chemical analyses for major, trace and rare earth elements. In addition, laser scanning survey (LIDAR) was also utilized in this study. The results of the stratigraphic investigations revealed that the lithofacies range from mudstone, wackestone, packestone and grainstone. These lithofacies represent environments ranging from supratidal, intertidal, subtidal and shoal complex. Several meter-scale and less high resolution sequences and composite sequences within 4th and 5th order cycles were also recognized in the outcrop analog. The lithofacies and architectural analysis revealed several vertically and laterally stacked sequences at the outcrop as revealed from the stratigraphic sections and the lidar scan. Chemostratigraphy is effective in identifying lithofacies and sequences within the outcrop analog. Moreover, different chemical signatures were also recognized and allowed establishing and correlating high resolution lithofacies, reservoir zones, layers and surfaces bounding reservoirs and non-reservoir zones at scale of meters or less. The results of this high resolution outcrop analog study might help to understand

  20. Sedimentary mode and reservoir distribution of the Cambrian carbonate & evaporate paragenesis system in the Sichuan Basin

    Anna Xu

    2016-11-01

    Full Text Available The Cambrian carbonate & evaporite paragenesis system in the Sichuan Basin is made up of the Longwangmiao, Gaotai and Xixiangchi Fms. So far, great breakthrough has been made only in the Longwangmiao Fm instead of the latter two, and the Anyue Gasfield was discovered in the center of this basin. In this paper, therefore, the Cambrian carbonate & evaporite paragenesis system in the Sichuan Basin was analyzed in terms of its structural–sedimentary setting, sequence stratigraphic framework, sedimentary facies and the distribution of evaporites by using various geologic, logging and seismic data. Then, the geological model of sedimentary facies was established and the distribution range of favorable reservoirs was predicted. Based on these studies, the following results are obtained. Firstly, the palaeotectonic framework is characterized by the style of “one depression between two uplifts” in the setting of a large SE dipping slope, and the stratigraphic filling is in the structure of “onlapping at the bottom and truncation at the top” which is thin in the west and thick in the east. Secondly, three third-order sequence cycles which, on the whole, become shallow upward are developed from bottom to top, and gypsum-salt rocks are mainly located at the high system tract (HST of third-order sequences and concentrated in the Wanzhou–Yibin sag. Thirdly, the geological model of sedimentary facies is composed of three major sedimentary structural layers from bottom to top, namely the evaporative carbonate ramp, the evaporative diamictic restricted platform and the evaporative restricted platform. The sedimentary environment changes from the open to the closed and the penesaline for a long time, and then back to the open. The distribution of shoals changes from the pattern of “dual banks” in a large area to more scattered shoals and banded shoals, while the evaporative lagoon and tidal flat shrink. Fourthly, the reservoir distribution is

  1. Enhanced heavy oil recovery for carbonate reservoirs integrating cross-well seismic–a synthetic Wafra case study

    Katterbauer, Klemens

    2015-07-14

    Heavy oil recovery has been a major focus in the oil and gas industry to counter the rapid depletion of conventional reservoirs. Various techniques for enhancing the recovery of heavy oil were developed and pilot-tested, with steam drive techniques proven in most circumstances to be successful and economically viable. The Wafra field in Saudi Arabia is at the forefront of utilizing steam recovery for carbonate heavy oil reservoirs in the Middle East. With growing injection volumes, tracking the steam evolution within the reservoir and characterizing the formation, especially in terms of its porosity and permeability heterogeneity, are key objectives for sound economic decisions and enhanced production forecasts. We have developed an integrated reservoir history matching framework using ensemble based techniques incorporating seismic data for enhancing reservoir characterization and improving history matches. Examining the performance on a synthetic field study of the Wafra field, we could demonstrate the improved characterization of the reservoir formation, determining more accurately the position of the steam chambers and obtaining more reliable forecasts of the reservoir’s recovery potential. History matching results are fairly robust even for noise levels up to 30%. The results demonstrate the potential of the integration of full-waveform seismic data for steam drive reservoir characterization and increased recovery efficiency.

  2. Chemical and physical characteristics of water and sediment in Scofield Reservoir, Carbon County, Utah

    Waddell, Kidd M.; Darby, D.W.; Theobald, S.M.

    1985-01-01

    Evaluations based on the nutrient content of the inflow, outflow, water in storage, and the dissolved-oxygen depletion during the summer indicate that the trophic state of Scofield Reservoir is borderline between mesotrophic and eutrophic and may become highly eutrophic unless corrective measures are taken to limit nutrient inflow.Sediment deposition in Scofield Reservoir during 1943-79 is estimated to be 3,000 acre-feet, and has decreased the original storage capacity of the reservoir by 4 percent. The sediment contains some coal, and age dating of those sediments (based on the radioisotope lead-210) indicates that most of the coal was deposited prior to about 1950.Scofield Reservoir is dimictic, with turnovers occurring in the spring and autumn. Water in the reservoir circulates completely to the bottom during turnovers. The concentration of dissolved oxygen decreases with depth except during parts of the turnover periods. Below an altitude of about 7,590 feet, where 20 percent of the water is stored, the concentration of dissolved oxygen was less than 2 milligrams per liter during most of the year. During the summer stratification period, the depletion of dissolved oxygen in the deeper layers is coincident with supersaturated conditions in the shallow layers; this is attributed to plant photosynthesis and bacterial respiration in the reservoir.During October 1,1979-August 31,1980, thedischargeweighted average concentrations of dissolved solids was 195 milligrams per liter in the combined inflow from Fish, Pondtown, and Mud Creeks, and was 175 milligrams per liter in the outflow (and to the Price River). The smaller concentration in the outflow was due primarily to precipitation of calcium carbonate in the reservoir about 80 percent of the decrease can be accounted for through loss as calcium carbonate.The estimated discharge-weighted average concentration of total nitrogen (dissolved plus suspended) in the combined inflow of Fish, Pondtown, and Mud Creeks was 1

  3. The FOODBANCS project: Introduction and sinking fluxes of organic carbon, chlorophyll- a and phytodetritus on the western Antarctic Peninsula continental shelf

    Smith, Craig R.; Mincks, Sarah; DeMaster, David J.

    2008-11-01

    The impact of the highly seasonal Antarctic primary production cycle on shelf benthic ecosystems remains poorly evaluated. Here we describe a times-series research project on the West Antarctic Peninsula (WAP) shelf designed to evaluate the seafloor deposition, and subsequent ecological and biogeochemical impacts, of the summer phytoplankton bloom along a transect crossing the Antarctic shelf near Anvers Island. During this project, entitled Food for Benthos on the Antarctic Continental Shelf (FOODBANCS), we deployed replicate sediment traps 150-170 m above the seafloor (total water-column depth of 590 m) on the central shelf from December 1999 to March 2001, recovering trap samples every 3-4 months. In addition, we used a seafloor time-lapse camera system, as well as video surveys conducted at 3-4 months intervals, to monitor the presence and accumulation of phytodetritus at the sediment-water interface. The fluxes of particulate organic carbon and chlorophyll- a into sediment traps (binned over 3-4 month intervals) showed patterns consistent with seasonal variability, with average summer fluxes during the first year exceeding winter fluxes by a factor of ˜2-3. However, inter-annual variability in summer fluxes was even greater than seasonal variability, with 4-10-fold differences in the flux of organic carbon and chlorophyll- a between the summer seasons of 1999-2000 and 2000-2001. Phytodetrital accumulation at the shelf floor also exhibited intense inter-annual variability, with no visible phytodetritus from essentially December 1999 to November 2000, followed by pulsed accumulation of 1-2 cm of phytodetritus over a ˜30,000 km 2 shelf area by March 2001. Comparisons with other studies suggest that the levels of inter-annual variability we observed are typical of the Antarctic shelf over decadal time scales. We conclude that fluxes of particulate organic carbon, chlorophyll- a and phytodetritus to WAP-shelf sediments vary intensely on seasonal to inter

  4. Analysis of Flow Behavior for Acid Fracturing Wells in Fractured-Vuggy Carbonate Reservoirs

    Mingxian Wang

    2018-01-01

    Full Text Available This study develops a mathematical model for transient flow analysis of acid fracturing wells in fractured-vuggy carbonate reservoirs. This model considers a composite system with the inner region containing finite number of artificial fractures and wormholes and the outer region showing a triple-porosity medium. Both analytical and numerical solutions are derived in this work, and the comparison between two solutions verifies the model accurately. Flow behavior is analyzed thoroughly by examining the standard log-log type curves. Flow in this composite system can be divided into six or eight main flow regimes comprehensively. Three or two characteristic V-shaped segments can be observed on pressure derivative curves. Each V-shaped segment corresponds to a specific flow regime. One or two of the V-shaped segments may be absent in particular cases. Effects of interregional diffusivity ratio and interregional conductivity ratio on transient responses are strong in the early-flow period. The shape and position of type curves are also influenced by interporosity coefficients, storativity ratios, and reservoir radius significantly. Finally, we show the differences between our model and the similar model with single fracture or without acid fracturing and further investigate the pseudo-skin factor caused by acid fracturing.

  5. Carbonic acid salts at 25 or 45 degrees C to control loquat decay under shelf life conditions.

    Molinu, M G; D'Hallewin, G; Dore, A; Serusi, A; Venditti, T; Agabbio, M

    2005-01-01

    Generally recognised as save compounds (G.R.A.S) are attractive substitutes to synthetic chemicals in postharvest control diseases. They meet safety requirements, are cheap and able to be integrated with other disease control technologies. Among G.R.A.S compounds, carbonic acid salts have been investigated on carrots, bell pepper, melons, sweet cherries and their efficacy was also evaluated when combined with biological control agents. Moreover, the possibility to use sodium carbonate and sodium bicarbonate to prevent P. digitatum an P. italicum spread on Citrus fruit was studied since the begin of the 20th century. We explored the possibility to extend the use of carbonate-bicarbonate salts on loquat fruit in order to control the pathogens and to extend postharvest life. Loquat is a very perishable fruit, susceptible to decay, mechanical damage, moisture and nutritional losses during its postharvest life. We tested the combined effect of temperature and sodium or potassium carbonate-bicarbonate and ammonium carbonate. The fruit was dipped in the salt solutions at variable concentrations (0.5, 1 and 2% w/v) at 25 or 45 degrees C for two minutes and than stored under shelf life conditions (25 degrees C and 70% RH). Decay, weight loss, pH, titrable acidity and sugar content were detected after twelve days. Preliminary data show that the combined treatments were effective in decay control depending on salts. Best results were obtained with 2% potassium and sodium carbonate solution at 25 degrees C. Weight losses were related to treatment temperature and salts concentrations whereas, no differences were detected in the chemical parameters compared to the control.

  6. Geochemical monitoring using noble gases and carbon isotopes: study of a natural reservoir

    Jeandel, E.

    2008-12-01

    To limit emissions of greenhouse gases in the atmosphere, CO 2 geological sequestration appears as a solution in the fight against climate change. The development of reliable monitoring tools to ensure the sustainability and the safety of geological storage is a prerequisite for the implementation of such sites. In this framework, a geochemical method using noble gas and carbon isotopes geochemistry has been tested on natural and industrial analogues. The study of natural analogues from different geological settings showed systematic behaviours of the geochemical parameters, depending on the containment sites, and proving the effectiveness of these tools in terms of leak detection and as tracers of the behaviour of CO 2 . Moreover, an experience of geochemical tracing on a natural gas storage has demonstrated that it is possible to identify the physical-chemical processes taking place in the reservoir to a human time scale, increasing interest in the proposed tool and providing general information on its use. (author)

  7. Nitrogen and carbon limitation of planktonic primary production and phytoplankton-bacterioplankton coupling in ponds on the McMurdo Ice Shelf, Antarctica

    Sorrell, B.K.; Hawes, I.; Safi, K.

    2013-01-01

    The nature of nutrient limitation and coupling of planktonic primary and secondary production were investigated in meltwater ponds of the Ross Ice Shelf, Antarctica, using regression tree analysis and multiple regression. Phytoplankton were primaril N-limited but inorganic carbon apparently co...

  8. Late Quaternary Halimeda bioherms and aragonitic faecal pellet-dominated sediments on the carbonate platform of the western continental shelf of India

    Rao, V.P; Veerayya, M.; Nair, R.R.; Dupeuble, P; Lamboy, M.

    brought by river runoff and shelf edge currents favoured the growth of algal bioherms dominated by Halimeda between 13,700 (?) and 8300 yr B.P. The absence of Late Holocene and modern carbonates on the platform may be due to the combined influence...

  9. Integrated Analysis Seismic Inversion and Rockphysics for Determining Secondary Porosity Distribution of Carbonate Reservoir at “FR” Field

    Rosid, M. S.; Augusta, F. F.; Haidar, M. W.

    2018-05-01

    In general, carbonate secondary pore structure is very complex due to the significant diagenesis process. Therefore, the determination of carbonate secondary pore types is an important factor which is related to study of production. This paper mainly deals not only to figure out the secondary pores types, but also to predict the distribution of the secondary pore types of carbonate reservoir. We apply Differential Effective Medium (DEM) for analyzing pore types of carbonate rocks. The input parameter of DEM inclusion model is fraction of porosity and the output parameters are bulk moduli and shear moduli as a function of porosity, which is used as input parameter for creating Vp and Vs modelling. We also apply seismic post-stack inversion technique that is used to map the pore type distribution from 3D seismic data. Afterward, we create porosity cube which is better to use geostatistical method due to the complexity of carbonate reservoir. Thus, the results of this study might show the secondary porosity distribution of carbonate reservoir at “FR” field. In this case, North – Northwest of study area are dominated by interparticle pores and crack pores. Hence, that area has highest permeability that hydrocarbon can be more accumulated.

  10. Satellite observation of particulate organic carbon dynamics on the Louisiana continental shelf

    Particulate organic carbon (POC) plays an important role in coastal carbon cycling and the formation of hypoxia. Yet, coastal POC dynamics are often poorly understood due to a lack of long-term POC observations and the complexity of coastal hydrodynamic and biogeochemical process...

  11. Origin and processing of terrestrial organic carbon in the Amazon system: lignin phenols in river, shelf, and fan sediments

    Sun, Shuwen; Schefuß, Enno; Mulitza, Stefan; Chiessi, Cristiano M.; Sawakuchi, André O.; Zabel, Matthias; Baker, Paul A.; Hefter, Jens; Mollenhauer, Gesine

    2017-05-01

    The Amazon River transports large amounts of terrestrial organic carbon (OCterr) from the Andean and Amazon neotropical forests to the Atlantic Ocean. In order to compare the biogeochemical characteristics of OCterr in the fluvial sediments from the Amazon drainage basin and in the adjacent marine sediments, we analysed riverbed sediments from the Amazon mainstream and its main tributaries as well as marine surface sediments from the Amazon shelf and fan for total organic carbon (TOC) content, organic carbon isotopic composition (δ13CTOC), and lignin phenol compositions. TOC and lignin content exhibit positive correlations with Al / Si ratios (indicative of the sediment grain size) implying that the grain size of sediment discharged by the Amazon River plays an important role in the preservation of TOC and leads to preferential preservation of lignin phenols in fine particles. Depleted δ13CTOC values (-26.1 to -29.9 ‰) in the main tributaries consistently correspond with the dominance of C3 vegetation. Ratios of syringyl to vanillyl (S / V) and cinnamyl to vanillyl (C / V) lignin phenols suggest that non-woody angiosperm tissues are the dominant source of lignin in the Amazon basin. Although the Amazon basin hosts a rich diversity of vascular plant types, distinct regional lignin compositions are not observed. In the marine sediments, the distribution of δ13CTOC and Λ8 (sum of eight lignin phenols in organic carbon (OC), expressed as mg/100 mg OC) values implies that OCterr discharged by the Amazon River is transported north-westward by the North Brazil Current and mostly deposited on the inner shelf. The lignin compositions in offshore sediments under the influence of the Amazon plume are consistent with the riverbed samples suggesting that processing of OCterr during offshore transport does not change the encoded source information. Therefore, the lignin compositions preserved in these offshore sediments can reliably reflect the vegetation in the Amazon

  12. Distribution and Thermal Maturity of Devonian Carbonate Reservoir Solid Bitumen in Desheng Area of Guizhong Depression, South China

    Yuguang Hou

    2017-01-01

    Full Text Available The distribution of solid bitumen in the Devonian carbonate reservoir from well Desheng 1, Guizhong Depression, was investigated by optical microscope and hydrocarbon inclusions analysis. Vb and chemical structure indexes measured by bitumen reflectance, laser Raman microprobe (LRM, and Fourier transform infrared spectroscopy (FTIR were carried out to determine the thermal maturity of solid bitumen. Based on the solid bitumen thermal maturity, the burial and thermal maturity history of Devonian carbonate reservoir were reconstructed by basin modeling. The results indicate that the fractures and fracture-related dissolution pores are the main storage space for the solid bitumen. The equivalent vitrinite reflectance of solid bitumen ranges from 3.42% to 4.43% converted by Vb (% and LRM. The infrared spectroscopy analysis suggests that there are no aliphatic chains detected in the solid bitumen which is rich in aromatics C=C chains (1431–1440 cm−1. The results of Vb (%, LRM, and FTIR analysis demonstrate that the solid bitumen has experienced high temperature and evolved to the residual carbonaceous stage. The thermal evolution of Devonian reservoirs had experienced four stages. The Devonian reservoirs reached the highest reservoir temperature 210–260°C during the second rapid burial-warming stage, which is the main period for the solid bitumen formation.

  13. Geochemical analysis of atlantic rim water, carbon county, wyoming: New applications for characterizing coalbed natural gas reservoirs

    McLaughlin, J.F.; Frost, C.D.; Sharma, Shruti

    2011-01-01

    Coalbed natural gas (CBNG) production typically requires the extraction of large volumes of water from target formations, thereby influencing any associated reservoir systems. We describe isotopic tracers that provide immediate data on the presence or absence of biogenic natural gas and the identify methane-containing reservoirs are hydrologically confined. Isotopes of dissolved inorganic carbon and strontium, along with water quality data, were used to characterize the CBNG reservoirs and hydrogeologic systems of Wyoming's Atlantic Rim. Water was analyzed from a stream, springs, and CBNG wells. Strontium isotopic composition and major ion geochemistry identify two groups of surface water samples. Muddy Creek and Mesaverde Group spring samples are Ca-Mg-S04-type water with higher 87Sr/86Sr, reflecting relatively young groundwater recharged from precipitation in the Sierra Madre. Groundwaters emitted from the Lewis Shale springs are Na-HCO3-type waters with lower 87Sr/86Sr, reflecting sulfate reduction and more extensive water-rock interaction. To distinguish coalbed waters, methanogenically enriched ??13CDIC wasused from other natural waters. Enriched ??13CDIC, between -3.6 and +13.3???, identified spring water that likely originates from Mesaverde coalbed reservoirs. Strongly positive ??13CDIC, between +12.6 and +22.8???, identified those coalbed reservoirs that are confined, whereas lower ??13CDIC, between +0.0 and +9.9???, identified wells within unconfined reservoir systems. Copyright ?? 2011. The American Association of Petroleum Geologists. All rights reserved.

  14. An Experimental Study of Surfactant Alternating CO2 Injection for Enhanced Oil Recovery of Carbonated Reservoir

    Asghar Gandomkar

    2016-10-01

    Full Text Available Core flooding experiments were conducted with the objective of evaluating near miscible surfactant alternating CO2 injection and the effect of surfactant concentrations on gas-oil and water displacements in porous media. The core samples were provided from a low permeability mixed wet oil reservoir at 156 °F and 1900 psia. In addition, very few studies of surfactant adsorption on carbonate minerals have been conducted. Hence, the surfactant adsorption on carbonate rock was determined by core flooding and crushed tests. It was found that for the crushed rock, the required equilibrium time is approximately five hours, while it is more than four days for the flow-through tests. Hysteresis effects demonstrated that the irreducible water saturations were 5 to 10% higher than the initial connate water saturation after drainage cycles during 5000 ppm surfactant solution. Furthermore, near-miscible surfactant alternating CO2 injection process led to a 4-17% increase in the recovery factor in comparison to water alternating gas process.

  15. 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

    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.

  16. Foraminiferal assemblages and organic carbon relationship in benthic marine ecosystem of Western Indian Continental Shelf

    Setty, M.G.A.P.; Nigam, R.

    that Ammobaculites agglutinans (d'Orbigny) and Ammonia spp have positive (direct) tendency towards organic carbon while miliolids (Quinqueloqulina spp, Spiroloculina spp and Triloculina spp Florilus-Nonion and Nonionella spp have negative (inverse) tendency...

  17. Experimental reactivity with CO2 of clayey cap-rock and carbonate reservoir of the Paris basin

    Hubert, G.

    2009-01-01

    The constant increase in the quantity of carbon dioxide in the atmosphere is regarded as being the principal cause of the current global warming. The geological sequestration of CO 2 seems to be an ideal solution to reduce the increase of greenhouse gases (of which CO 2 ) in the atmosphere but only if the reservoir's cap-rock keep its integrity for several hundreds or thousands of years. Batch experimental simulations were conducted to observe the reactivity of a cap-rock made of clay and a carbonate reservoir with CO 2 at 80 C and 150 C for a pressure of 150 bar with an equilibrated water. The analytical protocol established allowed to compare the rocks before and after experimentations finding a very low reactivity, focusing on aluminium in phyllosilicates. Textural analysis shows that CO 2 does not affect the properties of adsorption and the specific surface. The study of carbonate reservoir by confocal microscopy has revealed phenomena of dissolution-precipitation which have no significant impact on chemistry and structure of the reservoir. The numerical simulations carried out on mineral reference as calcium montmorillonite or clinochlore show a significant reaction in the presence of CO 2 not achieved experimentally, probably due to lacunas in the thermodynamic databases or the kinetics of reactions. The simulations on Bure show no reaction on the major minerals confirming the results with batch experiments. (author)

  18. Carbon-oxygen log applications in complex reservoir evaluation by neutron interactions from (D,T) accelerators

    Lochmann, M.J.; Berg, L.O.; Ivey, R.C.

    1983-01-01

    Granite Wash reservoirs in Oklahoma, Texas, Colorado and New Mexico have proven to be effective commercial producers of hydrocarbons. Substantial drilling activity continues to penetrate this formation either as a primary or secondary objective. A new technique to provide additional lithologic data to engineers and geologists will yield significant benefits in the evaluation and treatment of these reservoirs. This information can be obtained by data available from spectrum analysis through the use of tools such as the Carbon/Oxygen Log, Spectralog and NGS

  19. Highly CO2-supersaturated melts in the Pannonian lithospheric mantle - A transient carbon reservoir?

    Créon, Laura; Rouchon, Virgile; Youssef, Souhail; Rosenberg, Elisabeth; Delpech, Guillaume; Szabó, Csaba; Remusat, Laurent; Mostefaoui, Smail; Asimow, Paul D.; Antoshechkina, Paula M.; Ghiorso, Mark S.; Boller, Elodie; Guyot, François

    2017-08-01

    Subduction of carbonated crust is widely believed to generate a flux of carbon into the base of the continental lithospheric mantle, which in turn is the likely source of widespread volcanic and non-volcanic CO2 degassing in active tectonic intracontinental settings such as rifts, continental margin arcs and back-arc domains. However, the magnitude of the carbon flux through the lithosphere and the budget of stored carbon held within the lithospheric reservoir are both poorly known. We provide new constraints on the CO2 budget of the lithospheric mantle below the Pannonian Basin (Central Europe) through the study of a suite of xenoliths from the Bakony-Balaton Highland Volcanic Field. Trails of secondary fluid inclusions, silicate melt inclusions, networks of melt veins, and melt pockets with large and abundant vesicles provide numerous lines of evidence that mantle metasomatism affected the lithosphere beneath this region. We obtain a quantitative estimate of the CO2 budget of the mantle below the Pannonian Basin using a combination of innovative analytical and modeling approaches: (1) synchrotron X-ray microtomography, (2) NanoSIMS, Raman spectroscopy and microthermometry, and (3) thermodynamic models (Rhyolite-MELTS). The three-dimensional volumes reconstructed from synchrotron X-ray microtomography allow us to quantify the proportions of all petrographic phases in the samples and to visualize their textural relationships. The concentration of CO2 in glass veins and pockets ranges from 0.27 to 0.96 wt.%, higher than in typical arc magmas (0-0.25 wt.% CO2), whereas the H2O concentration ranges from 0.54 to 4.25 wt.%, on the low end for estimated primitive arc magmas (1.9-6.3 wt.% H2O). Trapping pressures for vesicles were determined by comparing CO2 concentrations in glass to CO2 saturation as a function of pressure in silicate melts, suggesting pressures between 0.69 to 1.78 GPa. These values are generally higher than trapping pressures for fluid inclusions

  20. Radiocarbon constraints on the coupled growth of sediment and organic carbon reservoirs in fluvial systems

    Torres, M. A.; Kemeny, P. C.; Fischer, W. W.; Lamb, M. P.

    2017-12-01

    Vast amounts of sediments are stored transiently in fluvial deposits as they move in rivers from source to sink. The timescale(s) of transient storage have the potential to set the cadence for biogeochemical reactions to occur in river sediments. However, the extent to which storage modulates the chemical composition of river sediments remains unclear. In case of the organic carbon (OC) cycle, transient sediment storage may leave an imprint in the radiocarbon (14C) content of riverine particulate OC (POC), offering a potential tool to trace the coupling of sediment storage and biogeochemical cycling in river systems. We investigated the modern and ancient budgets of sediments and POC in the Efi Haukadalsá River catchment in West Iceland to provide new empirical constraints on the role of sediment storage in the terrestrial OC cycle. This field site is attractive because the basaltic bedrock is free of rock-derived (i.e. "petrogenic") POC such that bulk 14C measurements can be interpreted more directly as constraints on catchment OC storage timescales. Additionally, Lake Haukadalsvatn at the outlet of the river catchment has captured sediment for nearly 13 ka, which offers a complementary record of the evolution of climate-sediment-OC linkages since deglaciation. New 14C measurements show that bulk POC in fine grained fluvial deposits within the Haukadalsá catchment is remarkably old (model ages between 1 and 10 ka). This evidence for "aged" POC in floodplain storage is consistent with previous measurements from Lake Haukadalsvatn, which show that POC is aged in the river system by thousands of years prior to deposition in the lake. Additionally, our estimate of the mean transit time of sediments through the river system matches the millennial-scale reservoir age of riverine POC derived from 14C, which implies a tight coupling between sediment storage and the OC cycle. We interpret the long-term increase in the 14C reservoir age of riverine POC over the last 10 ka

  1. The Influence of Seal Properties on Pressure Buildup and Leakage of Carbon Dioxide from Sequestration Reservoirs (Invited)

    Benson, S. M.; Chabora, E.

    2009-12-01

    The transport properties of seals, namely permeability, relative permeability, and capillary pressure control both migration of carbon dioxide and brine through the seal. Only recently has the the importance of brine migration emerged as key issue in the environmental performance of carbon dioxide sequestration projects. In this study we use numerical simulation to show that brine migration through the seal can be either advantageous or deleterious to the environmental performance of a carbon dioxide sequestration project. Brine migration through the seal can lower the pressure buildup in the storage reservoir, thereby reducing the risk of leakage or geomechanical stresses on the seal. On the other hand, if the seal is penetrated by a permeable fault it can lead to focused flow up a fault, which could lead to brine migration into drinking water aquifers. We also show that as the carbon dioxide plume grows, brine flow undergoes a complex evolution from upward flow to downward flows driven by countercurrent migration of carbon dioxide and brine in the seal and capillary pressure gradients at the base of the seal. Finally, we discuss desirable attributes seals, taking into account both carbon dioxide and brine migration through the seal. In particular, identifying seals that provide an effective capillary barrier to block the flow of carbon dioxide while allowing some brine migration through the seal can help to control pressure buildup and allow more efficient utilization of a sequestration reservoir. This could be particularly important in those settings that may be limited by the maximum allowable pressure buildup.

  2. Toward a quantitative and empirical dissolved organic carbon budget for the Gulf of Maine, a semienclosed shelf sea

    Balch, William; Huntington, Thomas; Aiken, George; Drapeau, David; Bowler, Bruce; Lubelczyk, Laura; Butler, Kenna

    2016-02-01

    A time series of organic carbon export from Gulf of Maine (GoM) watersheds was compared to a time series of biological, chemical, bio-optical, and hydrographic properties, measured across the GoM between Yarmouth, NS, Canada, and Portland, ME, U.S. Optical proxies were used to quantify the dissolved organic carbon (DOC) and particulate organic carbon in the GoM. The Load Estimator regression model applied to river discharge data demonstrated that riverine DOC export (and its decadal variance) has increased over the last 80 years. Several extraordinarily wet years (2006-2010) resulted in a massive pulse of chromophoric dissolved organic matter (CDOM; proxy for DOC) into the western GoM along with unidentified optically scattering material (DOC in the GoM and Scotian Shelf showed the strong influence of the Gulf of Saint Lawrence on the DOC that enters the GoM. A deep plume of CDOM-rich water was observed near the coast of Maine which decreased in concentration eastward. The Forel-Ule color scale was derived and compared to the same measurements made in 1912-1913 by Henry Bigelow. Results show that the GoM has yellowed in the last century, particularly in the region of the extension of the Eastern Maine Coastal Current. Time lags between DOC discharge and its appearance in the GoM increased with distance from the river mouths. Algae were also a significant source of DOC but not CDOM. Gulf-wide algal primary production has decreased. Increases in precipitation and DOC discharge to the GoM are predicted over the next century.

  3. Ecomorphological and taphonomic gradients in clypeasteroid-dominated echinoid assemblages along a mixed siliciclastic-carbonate shelf from the early Miocene of northern Sardinia, Italy

    Andrea Mancosu

    2017-09-01

    Full Text Available Clypeasteroid echinoids are widespread and abundant within Miocene sedimentary sequences of the Mediterranean area within both siliciclastic and carbonate deposits. Herein, three clypeasteroid-dominated echinoid assemblages from the mixed siliciclastic-carbonate succession of the Mores Formation (lower Miocene cropping out within the Porto Torres Basin (northern Sardinia are described. These assemblages were compared to previously described clypeasteroid-bearing deposits from the Miocene of northern Sardinia with the purpose of investigating their palaeoecology and taphonomy along a shelf gradient. These goals are accomplished by various methods including (i logging sedimentary facies, (ii analysing the functional morphology of sea urchin skeletons, (iii comparing the relative abundance of taxa and taphonomic features, and (iv studying associated fauna, flora, and trace fossils. The clypeasteroid-bearing deposits differ greatly with respect to echinoid diversity, accompanying fauna and flora, sedimentological signatures, and taphonomic features. They also show variations in depositional environments and the mechanism of formation of the deposits. Three different shelf settings are distinguished: littoral, inner sublittoral, and outer sublittoral environments. Furthermore, an ecomorphological gradient along the shelf is recognized with respect to echinoid taxa and their morphologies. This gradient ranges from shallow water to a moderately deep shelf and is interpreted with respect to both abiotic and biotic factors as well as the taphonomy of the echinoid tests.

  4. Using Biosurfactants Produced from Agriculture Process Waste Streams to Improve Oil Recovery in Fractured Carbonate Reservoirs

    Stephen Johnson; Mehdi Salehi; Karl Eisert; Sandra Fox

    2009-01-07

    This report describes the progress of our research during the first 30 months (10/01/2004 to 03/31/2007) of the original three-year project cycle. The project was terminated early due to DOE budget cuts. This was a joint project between the Tertiary Oil Recovery Project (TORP) at the University of Kansas and the Idaho National Laboratory (INL). The objective was to evaluate the use of low-cost biosurfactants produced from agriculture process waste streams to improve oil recovery in fractured carbonate reservoirs through wettability mediation. Biosurfactant for this project was produced using Bacillus subtilis 21332 and purified potato starch as the growth medium. The INL team produced the biosurfactant and characterized it as surfactin. INL supplied surfactin as required for the tests at KU as well as providing other microbiological services. Interfacial tension (IFT) between Soltrol 130 and both potential benchmark chemical surfactants and crude surfactin was measured over a range of concentrations. The performance of the crude surfactin preparation in reducing IFT was greater than any of the synthetic compounds throughout the concentration range studied but at low concentrations, sodium laureth sulfate (SLS) was closest to the surfactin, and was used as the benchmark in subsequent studies. Core characterization was carried out using both traditional flooding techniques to find porosity and permeability; and NMR/MRI to image cores and identify pore architecture and degree of heterogeneity. A cleaning regime was identified and developed to remove organic materials from cores and crushed carbonate rock. This allowed cores to be fully characterized and returned to a reproducible wettability state when coupled with a crude-oil aging regime. Rapid wettability assessments for crushed matrix material were developed, and used to inform slower Amott wettability tests. Initial static absorption experiments exposed limitations in the use of HPLC and TOC to determine

  5. Changes in water mass exchange between the NW shelf areas and the North Atlantic and their impact on nutrient/carbon cycling

    Gröger, Matthias; Maier-Reimer, Ernst; Mikolajewicz, Uwe; Segschneider, Joachim; Sein, Dimitry

    2010-05-01

    Despite their comparatively small extension on a global scale, shelf areas are of interest for several economic reasons and climatic processes related to nutrient cycling, sea food supply, and biological productivity. Moreover, they constitute an important interface for nutrients, pollutants and freshwater on their pathway from the continents to the open ocean. This modelling study aims to investigate the spatial and temporal variability of water mass exchange between the North Atlantic and the NW European shelf and their impact on nutrient/carbon cycling and biological productivity. For this, a new modeling approach has been set up which bridges the gap between pure shelf models where water mass transports across the model domain too strongly depend on the formulation of open boundaries and global models suffering under their too coarse resolution in shelf regions. The new model consists of the global ocean and carbon cycle model MPIOM/HAMOCC with strongly increased resolution in the North Sea and the North Atlantic coupled to the regional atmosphere model REMO. The model takes the full luni-solar tides into account. It includes further a 12 layer sediment module with the relevant pore water chemistry. The main focus lies on the governing mechanisms of water mass exchange across the shelf break and the imprint on shelf biogeochemistry. For this, artificial tracers with a prescribed decay rate have been implemented to distinguish waters arriving from polar and shelf regions and those that originate from the tropics. Experiments were carried out for the years 1948 - 2007. The relationship to larger scale circulation patterns like the position and variability of the subtropical and subpolar gyres is analyzed. The water mass exchange is analyzed with respect to the nutrient concentration and productivity on the European shelf areas. The implementation of tides leads to an enhanced vertical mixing which causes lower sea surface temperatures compared to simulations

  6. Discontinuities Characteristics of the Upper Jurassic Arab-D Reservoir Equivalent Tight Carbonates Outcrops, Central Saudi Arabia

    Abdlmutalib, Ammar; Abdullatif, Osman

    2017-04-01

    Jurassic carbonates represent an important part of the Mesozoic petroleum system in the Arabian Peninsula in terms of source rocks, reservoirs, and seals. Jurassic Outcrop equivalents are well exposed in central Saudi Arabia and which allow examining and measuring different scales of geological heterogeneities that are difficult to collect from the subsurface due to limitations of data and techniques. Identifying carbonates Discontinuities characteristics at outcrops might help to understand and predict their properties and behavior in the subsurface. The main objective of this study is to identify the lithofacies and the discontinuities properties of the upper Jurassic carbonates of the Arab D member and the Jubaila Formation (Arab-D reservoir) based on their outcrop equivalent strata in central Saudi Arabia. The sedimentologic analysis revealed several lithofacies types that vary in their thickness, abundances, cyclicity and vertical and lateral stacking patterns. The carbonates lithofacies included mudstone, wackestone, packstone, and grainstone. These lithofacies indicate deposition within tidal flat, skeletal banks and shallow to deep lagoonal paleoenvironmental settings. Field investigations of the outcrops revealed two types of discontinuities within Arab D Member and Upper Jubaila. These are depositional discontinuities and tectonic fractures and which all vary in their orientation, intensity, spacing, aperture and displacements. It seems that both regional and local controls have affected the fracture development within these carbonate rocks. On the regional scale, the fractures seem to be structurally controlled by the Central Arabian Graben System, which affected central Saudi Arabia. While, locally, at the outcrop scale, stratigraphic, depositional and diagenetic controls appear to have influenced the fracture development and intensity. The fracture sets and orientations identified on outcrops show similarity to those fracture sets revealed in the upper

  7. Modeling and optimizing the design of matrix treatments in carbonate reservoirs with self-diverting acid systems

    Bulgakova, G T; Kharisov, R Ya; Sharifullin, A R; Pestrikov, A V

    2015-01-01

    Application of a self-diverting-acid based on viscoelastic surfactant (SDVA) is a promising technology for improving the efficacy of acid treatment in oil and gas-bearing carbonate reservoirs. In this study, we present a mathematical model for assessing SDVA flow and reaction with carbonate rock using the SDVA rheological characteristics. The model calculates the technological parameters for acidizing operations and the prediction of well productivity after acid treatment, in addition to technical and economic optimization of the acidizing process by modeling different acid treatment options with varying volumes, injection rates, process fluids stages and initial economic scenarios

  8. Bacteria, carbon dioxide, and methane data from bottle casts in the Cariaco Basin on the continental shelf of Venezuela from the HERMANO GINES from 2001-04-30 to 2001-05-01 (NODC Accession 0000737)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bacteria, carbon dioxide, and methane data were collected from bottle casts from the HERMANO GINES in the Cariaco Basin on the continental shelf of Venezuela. Data...

  9. Bacteria, carbon dioxide, and methane data from bottle casts in the Cariaco Basin on the continental shelf of Venezuela from the HERMANO GINES from 2000-05-03 to 2000-10-31 (NODC Accession 0000732)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bacteria, carbon dioxide, and methane data were collected employing bottle casts from the Hermano Gines in the Cariaco Basin on the continental shelf of Venezuela....

  10. Flux, Budget and Sources of Black Carbon (BC) in the Continental Shelf of the Bohai and Yellow Seas, China

    Fang, Y.; Chen, Y.; Tian, C.

    2015-12-01

    Black carbon (BC) derived from incomplete combustion of fossil fuels and biomass has received increasing attention due to their potential importance in a wide range of biogeochemical processes. China has been generally considered as the world's largest BC emitter. Due to a combination of the prevailing East Asia monsoon and large amounts of riverine outflow, BC released from China can be transported to the adjacent continental shelf seas, the Bohai Sea (BS) and Yellow Sea (YS). Based on measurements of BC in 191 surface sediments, 36 riverine water, and 2 seawater samples, as well as the reported BC data set of the aerosol samples in the Bohai Rim, the concentration, flux, and budget of BC in the BS and YS were investigated. The spatial distribution of the BC concentration in surface sediments was largely influenced by the regional hydrodynamic conditions, with high values mainly occurring in the central mud areas. The BC burial flux in the BS and YS ranged from 4 to 1100 μg/cm2/yr, and averaged 166 ± 200 μg/cm2/yr. The area-integrated sedimentary BC sink flux in the entire BS and YS was ~325 Gg/yr. The BC budget calculated in the BS showed that atmospheric deposition and riverine discharge played comparable importance in delivering BC to the BS, and sequestration to bottom sediments was the major BC output pattern, accounting for ~88% of the total input BC. Besides, we attempted to apportion the BC sources in the BS and YS surface sediments using PAHs (organic molecular proxies cogenerated with BC) and BC as an input data to the Positive Matrix Factorization (PMF) receptor model. Results showed that ~83% of the sediment BC was attributed to the combustion of fossil fuels, and the remaining ~17% was from biomass burning. Due to the differences in their production mechanisms and therefore physicochemical properties, the above distinction and quantification would help us better understand their different environmental behaviors in the complex continental shelf

  11. Cost Effective Surfactant Formulations for Improved Oil Recovery in Carbonate Reservoirs

    William A. Goddard; Yongchun Tang; Patrick Shuler; Mario Blanco; Yongfu Wu

    2007-09-30

    This report summarizes work during the 30 month time period of this project. This was planned originally for 3-years duration, but due to its financial limitations, DOE halted funding after 2 years. The California Institute of Technology continued working on this project for an additional 6 months based on a no-cost extension granted by DOE. The objective of this project is to improve the performance of aqueous phase formulations that are designed to increase oil recovery from fractured, oil-wet carbonate reservoir rock. This process works by increasing the rate and extent of aqueous phase imbibition into the matrix blocks in the reservoir and thereby displacing crude oil normally not recovered in a conventional waterflood operation. The project had three major components: (1) developing methods for the rapid screening of surfactant formulations towards identifying candidates suitable for more detailed evaluation, (2) more fundamental studies to relate the chemical structure of acid components of an oil and surfactants in aqueous solution as relates to their tendency to wet a carbonate surface by oil or water, and (3) a more applied study where aqueous solutions of different commercial surfactants are examined for their ability to recover a West Texas crude oil from a limestone core via an imbibition process. The first item, regarding rapid screening methods for suitable surfactants has been summarized as a Topical Report. One promising surfactant screening protocol is based on the ability of a surfactant solution to remove aged crude oil that coats a clear calcite crystal (Iceland Spar). Good surfactant candidate solutions remove the most oil the quickest from the surface of these chips, plus change the apparent contact angle of the remaining oil droplets on the surface that thereby indicate increased water-wetting. The other fast surfactant screening method is based on the flotation behavior of powdered calcite in water. In this test protocol, first the calcite

  12. Reduced-Order Model for Leakage Through an Open Wellbore from the Reservoir due to Carbon Dioxide Injection

    Pan, Lehua [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Oldenburg, Curtis M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-07-26

    Potential CO2 leakage through existing open wellbores is one of the most significant hazards that need to be addressed in geologic carbon sequestration (GCS) projects. In the framework of the National Risk Assessment Partnership (NRAP) which requires fast computations for uncertainty analysis, rigorous simulation of the coupled wellbore-reservoir system is not practical. We have developed a 7,200-point look-up table reduced-order model (ROM) for estimating the potential leakage rate up open wellbores in response to CO2 injection nearby. The ROM is based on coupled simulations using T2Well/ECO2H which was run repeatedly for representative conditions relevant to NRAP to create a look-up table response-surface ROM. The ROM applies to a wellbore that fully penetrates a 20-m thick reservoir that is used for CO2 storage. The radially symmetric reservoir is assumed to have initially uniform pressure, temperature, gas saturation, and brine salinity, and it is assumed these conditions are held constant at the far-field boundary (100 m away from the wellbore). In such a system, the leakage can quickly reach quasi-steady state. The ROM table can be used to estimate both the free-phase CO2 and brine leakage rates through an open well as a function of wellbore and reservoir conditions. Results show that injection-induced pressure and reservoir gas saturation play important roles in controlling leakage. Caution must be used in the application of this ROM because well leakage is formally transient and the ROM lookup table was populated using quasi-steady simulation output after 1000 time steps which may correspond to different physical times for the various parameter combinations of the coupled wellbore-reservoir system.

  13. Characterization of nanometer-scale porosity in reservoir carbonate rock by focused ion beam-scanning electron microscopy.

    Bera, Bijoyendra; Gunda, Naga Siva Kumar; Mitra, Sushanta K; Vick, Douglas

    2012-02-01

    Sedimentary carbonate rocks are one of the principal porous structures in natural reservoirs of hydrocarbons such as crude oil and natural gas. Efficient hydrocarbon recovery requires an understanding of the carbonate pore structure, but the nature of sedimentary carbonate rock formation and the toughness of the material make proper analysis difficult. In this study, a novel preparation method was used on a dolomitic carbonate sample, and selected regions were then serially sectioned and imaged by focused ion beam-scanning electron microscopy. The resulting series of images were used to construct detailed three-dimensional representations of the microscopic pore spaces and analyze them quantitatively. We show for the first time the presence of nanometer-scale pores (50-300 nm) inside the solid dolomite matrix. We also show the degree of connectivity of these pores with micron-scale pores (2-5 μm) that were observed to further link with bulk pores outside the matrix.

  14. Biomass-derived porous carbon modified glass fiber separator as polysulfide reservoir for Li-S batteries.

    Selvan, Ramakrishnan Kalai; Zhu, Pei; Yan, Chaoi; Zhu, Jiadeng; Dirican, Mahmut; Shanmugavani, A; Lee, Yun Sung; Zhang, Xiangwu

    2018-03-01

    Biomass-derived porous carbon has been considered as a promising sulfur host material for lithium-sulfur batteries because of its high conductive nature and large porosity. The present study explored biomass-derived porous carbon as polysulfide reservoir to modify the surface of glass fiber (GF) separator. Two different carbons were prepared from Oak Tree fruit shells by carbonization with and without KOH activation. The KOH activated porous carbon (AC) provides a much higher surface area (796 m 2  g -1 ) than pyrolized carbon (PC) (334 m 2  g -1 ). The R factor value, calculated from the X-ray diffraction pattern, revealed that the activated porous carbon contains more single-layer sheets with a lower degree of graphitization. Raman spectra also confirmed the presence of sp 3 -hybridized carbon in the activated carbon structure. The COH functional group was identified through X-ray photoelectron spectroscopy for the polysulfide capture. Simple and straightforward coating of biomass-derived porous carbon onto the GF separator led to an improved electrochemical performance in Li-S cells. The Li-S cell assembled with porous carbon modified GF separator (ACGF) demonstrated an initial capacity of 1324 mAh g -1 at 0.2 C, which was 875 mAh g -1 for uncoated GF separator (calculated based on the 2nd cycle). Charge transfer resistance (R ct ) values further confirmed the high ionic conductivity nature of porous carbon modified separators. Overall, the biomass-derived activated porous carbon can be considered as a promising alternative material for the polysulfide inhibition in Li-S batteries. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Diffusive emission of methane and carbon dioxide from two hydropower reservoirs in Brazil.

    Marcelino, A A; Santos, M A; Xavier, V L; Bezerra, C S; Silva, C R O; Amorim, M A; Rodrigues, R P; Rogerio, J P

    2015-05-01

    The role of greenhouse gas emissions from freshwater reservoirs and their contribution to increase greenhouse gas concentrations in the atmosphere is currently under discussion in many parts of the world. We studied CO2 and CH4 diffusive fluxes from two large neotropical hydropower reservoirs with different climate conditions. We used floating closed-chambers to estimate diffusive fluxes of these gaseous species. Sampling campaigns showed that the reservoirs studied were sources of greenhouse gases to the atmosphere. In the Serra da Mesa Reservoir, the CH4 emissions ranged from 0.530 to 396.96 mg.m(-2).d(-1) and CO2 emissions ranged from -1,738.33 to 11,166.61 mg.m(-2).d(-1) and in Três Marias Reservoir the CH4 fluxes ranged 0.720 to 2,578.03 mg.m(-2).d(-1) and CO2 emission ranged from -3,037.80 to 11,516.64 to mg.m(-2).d(-1). There were no statistically significant differences of CH4 fluxes between the reservoirs, but CO2 fluxes from the two reservoirs studied were significantly different. The CO2 emissions measured over the periods studied in Serra da Mesa showed some seasonality with distinctions between the wet and dry transition season. In Três Marias Reservoir the CO2 fluxes showed no seasonal variability. In both reservoirs, CH4 emissions showed a tendency to increase during the study periods but this was not statistically significant. These results contributed to increase knowledge about the magnitude of CO2 and CH4 emission in hydroelectric reservoirs, however due to natural variability of the data future sampling campaigns will be needed to better elucidate the seasonal influences on the fluxes of greenhouse gases.

  16. Sedimentary record of water column trophic conditions and sediment carbon fluxes in a tropical water reservoir (Valle de Bravo, Mexico).

    Carnero-Bravo, Vladislav; Merino-Ibarra, Martín; Ruiz-Fernández, Ana Carolina; Sanchez-Cabeza, Joan Albert; Ghaleb, Bassam

    2015-03-01

    Valle de Bravo (VB) is the main water reservoir of the Cutzamala hydraulic system, which provides 40% of the drinking water consumed in the Mexico City Metropolitan Area and exhibits symptoms of eutrophication. Nutrient (C, N and P) concentrations were determined in two sediment cores to reconstruct the water column trophic evolution of the reservoir and C fluxes since its creation in 1947. Radiometric methods ((210)Pb and (137)Cs) were used to obtain sediment chronologies, using the presence of pre-reservoir soil layers in one of the cores as an independent chronological marker. Mass accumulation rates ranged from 0.12 to 0.56 g cm(-2) year(-1) and total organic carbon (TOC) fluxes from 122 to 380 g m(-2) year(-1). Total N ranged 4.9-48 g m(-2) year(-1), and total P 0.6-4.2 g m(-2) year(-1). The sedimentary record shows that all three (C, N and P) fluxes increased significantly after 1991, in good agreement with the assessed trophic evolution of VB and with historic and recent real-time measurements. In the recent years (1992-2006), the TOC flux to the bottom of VB (average 250 g m(-2) year(-1), peaks 323 g m(-2) year(-1)) is similar to that found in highly eutrophic reservoirs and impoundments. Over 1/3 of the total C burial since dam construction, circa 70,000 t, has occurred in this recent period. These results highlight the usefulness of the reconstruction of carbon and nutrient fluxes from the sedimentary record to assess carbon burial and its temporal evolution in freshwater ecosystems.

  17. Atmospheric transport simulations in support of the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE)

    Henderson, J. M.; Eluszkiewicz, J.; Mountain, M. E.; Nehrkorn, T.; Chang, R. Y.-W.; Karion, A.; Miller, J. B.; Sweeney, C.; Steiner, N.; Wofsy, S. C.; Miller, C. E.

    2015-04-01

    This paper describes the atmospheric modeling that underlies the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) science analysis, including its meteorological and atmospheric transport components (polar variant of the Weather Research and Forecasting (WRF) and Stochastic Time Inverted Lagrangian Transport (STILT) models), and provides WRF validation for May-October 2012 and March-November 2013 - the first 2 years of the aircraft field campaign. A triply nested computational domain for WRF was chosen so that the innermost domain with 3.3 km grid spacing encompasses the entire mainland of Alaska and enables the substantial orography of the state to be represented by the underlying high-resolution topographic input field. Summary statistics of the WRF model performance on the 3.3 km grid indicate good overall agreement with quality-controlled surface and radiosonde observations. Two-meter temperatures are generally too cold by approximately 1.4 K in 2012 and 1.1 K in 2013, while 2 m dewpoint temperatures are too low (dry) by 0.2 K in 2012 and too high (moist) by 0.6 K in 2013. Wind speeds are biased too low by 0.2 m s-1 in 2012 and 0.3 m s-1 in 2013. Model representation of upper level variables is very good. These measures are comparable to model performance metrics of similar model configurations found in the literature. The high quality of these fine-resolution WRF meteorological fields inspires confidence in their use to drive STILT for the purpose of computing surface influences ("footprints") at commensurably increased resolution. Indeed, footprints generated on a 0.1° grid show increased spatial detail compared with those on the more common 0.5° grid, better allowing for convolution with flux models for carbon dioxide and methane across the heterogeneous Alaskan landscape. Ozone deposition rates computed using STILT footprints indicate good agreement with observations and exhibit realistic seasonal variability, further indicating that WRF

  18. Well log and seismic data analysis for complex pore-structure carbonate reservoir using 3D rock physics templates

    Li, Hongbing; Zhang, Jiajia

    2018-04-01

    The pore structure in heterogeneous carbonate rock is usually very complex. This complex pore system makes the relationship between the velocity and porosity of the rock highly scattered, so that for the classical two-dimensional rock physics template (2D RPT) it is not enough to accurately describe the quantitative relationship between the rock elastic parameters of this kind of reservoir and its porosity and water saturation. Therefore it is possible to attribute the effect of pore type to that of the porosity or water saturation, and leads to great deviations when applying such a 2D RPT to predict the porosity and water saturation in seismic reservoir prediction and hydrocarbon detection. This paper first presents a method to establish a new three-dimensional rock physics template (3D RPT) by integrating the Gassmann equations and the porous rock physics model, and use it to characterize the quantitative relation between rock elastic properties and the reservoir parameters including the pore aspect ratio, porosity and water saturation, and to predict these parameters from the known elastic properties. The test results on the real logging and seismic inversion data show that the 3D RPT can accurately describe the variations of elastic properties with the porosity, water saturation and pore-structure parameters, and effectively improve the accuracy of reservoir parameters prediction.

  19. Application of probabilistic facies prediction and estimation of rock physics parameters in a carbonate reservoir from Iran

    Karimpouli, Sadegh; Hassani, Hossein; Nabi-Bidhendi, Majid; Khoshdel, Hossein; Malehmir, Alireza

    2013-01-01

    In this study, a carbonate field from Iran was studied. Estimation of rock properties such as porosity and permeability is much more challenging in carbonate rocks than sandstone rocks because of their strong heterogeneity. The frame flexibility factor (γ) is a rock physics parameter which is related not only to pore structure variation but also to solid/pore connectivity and rock texture in carbonate reservoirs. We used porosity, frame flexibility factor and bulk modulus of fluid as the proper parameters to study this gas carbonate reservoir. According to rock physics parameters, three facies were defined: favourable and unfavourable facies and then a transition facies located between these two end members. To capture both the inversion solution and associated uncertainty, a complete implementation of the Bayesian inversion of the facies from pre-stack seismic data was applied to well data and validated with data from another well. Finally, this method was applied on a 2D seismic section and, in addition to inversion of petrophysical parameters, the high probability distribution of favorable facies was also obtained. (paper)

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

    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

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

    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

  2. Biological and climate controls on North Atlantic marine carbon dynamics over the last millennium: Insights from an absolutely-dated shell based record from the North Icelandic Shelf

    Hall, I. R.; Reynolds, D.; Scourse, J. D.; Richardson, C.; Wanamaker, A. D.; Butler, P. G.

    2017-12-01

    Given the rapid increase in atmospheric carbon dioxide concentrations (pCO2) over the industrial era there is a pressing need to construct longterm records of natural carbon cycling prior to this perturbation and to develop a more robust understanding of the role the oceans play in the sequestration of atmospheric carbon. Here we reconstruct the historical biological and climatic controls on the carbon isotopic (δ13C-shell) composition of the North Icelandic shelf waters over the last millennium derived from the shells of the long-lived marine bivalve mollusc Arctica islandica. Variability in the annually resolved δ13C-shell record is dominated by multi-decadal variability with a negative trend (-0.003±0.002‰yr-1) over the industrial era (1800-2000). This trend is consistent with the marine Suess effect brought about by the sequestration of isotopically light carbon (δ13C of CO2) derived from the burning of fossil fuels. Comparison of the δ13C-shell record with contemporary proxy archives, over the last millennium, and instrumental data over the 20th century, suggests that primary productivity and climate conditions over the sub-polar North Atlantic region played a vital role in driving inter-annual to multi-decadal scale variability in the δ13C-shell record. Our results highlight that relative shifts in the proportion of sub-polar mode waters and Arctic intermediate waters entrained onto the North Icelandic shelf, coupled with atmospheric circulation patterns associated with the winter North Atlantic Oscillation (wNAO), are the likely physical mechanisms that drive natural variations in seawater δ13C variability on the North Icelandic shelf.

  3. Biological and Climate Controls on North Atlantic Marine Carbon Dynamics Over the Last Millennium: Insights From an Absolutely Dated Shell-Based Record From the North Icelandic Shelf

    Reynolds, D. J.; Hall, I. R.; Scourse, J. D.; Richardson, C. A.; Wanamaker, A. D.; Butler, P. G.

    2017-12-01

    Given the rapid increase in atmospheric carbon dioxide concentrations (pCO2) over the industrial era, there is a pressing need to construct long-term records of natural carbon cycling prior to this perturbation and to develop a more robust understanding of the role the oceans play in the sequestration of atmospheric carbon. Here we reconstruct the past biological and climate controls on the carbon isotopic (δ13Cshell) composition of the North Icelandic shelf waters over the last millennium, derived from the shells of the long-lived marine bivalve mollusk Arctica islandica. Variability in the annually resolved δ13Cshell record is dominated by multidecadal variability with a negative trend (-0.003 ± 0.002‰ yr-1) over the industrial era (1800-2000 Common Era). This trend is consistent with the marine Suess effect brought about by the sequestration of isotopically light carbon (δ13C of CO2) derived from the burning of fossil fuels. Comparison of the δ13Cshell record with Contemporaneous proxy archives, over the last millennium, and instrumental data over the twentieth century, highlights that both biological (primary production) and physical environmental factors, such as relative shifts in the proportion of Subpolar Mode Waters and Arctic Intermediate Waters entrained onto the North Icelandic shelf, atmospheric circulation patterns associated with the winter North Atlantic Oscillation, and sea surface temperature and salinity of the subpolar gyre, are the likely mechanisms that contribute to natural variations in seawater δ13C variability on the North Icelandic shelf. Contrasting δ13C fractionation processes associated with these biological and physical mechanisms likely cause the attenuated marine Suess effect signal at this locality.

  4. Fish mercury development in relation to abiotic characteristics and carbon sources in a six-year-old, Brazilian reservoir

    Tuomola, Leena; Niklasson, Terese [Evolutionary Biology Centre and Department of Limnology, Uppsala University, Norbyvaegen 20, S-752 36 Uppsala (Sweden); Castro e Silva, Edinaldo de [Departamento de Quimica, Universidade Federal de Mato Grosso (UFMT), Av. Fernando C. Costa/sn, 78 090-900 Cuiaba-MT (Brazil); Hylander, Lars D. [Department of Earth Sciences, Air, Water and Landscape Science, Uppsala University, Villavaegen 16, S-752 36 Uppsala (Sweden)], E-mail: Lars.Hylander@hyd.uu.se

    2008-02-01

    Time series on fish mercury (Hg) development are rare for hydroelectric reservoirs in the tropics. In the central-western part of Brazil, a hydroelectric reservoir, called Lago Manso, was completed in 1999 after that background levels of fish Hg concentrations had been determined. The development for the first 3 years was studied in 2002. The objective of the present study was to determine development of fish Hg concentrations for a second three-year period after flooding. The bioaccumulation factor and certain abiotic and biotic factors, possibly affecting the availability and accumulation of Hg, were also examined. The results show that Hg levels in fish from Lago Manso have increased more than five times compared to the background levels observed before construction of the reservoir. At the same time, dissolved organic carbon has increased while dissolved oxygen has decreased indicating enhanced bioavailability of Hg. In the reservoir, Salminus brasiliensis had in average a Hg content of 1.1 {mu}g g{sup -1} f.w., Pseudoplatystoma fasciatum 1.2, Serrasalmus marginatus/spilopleura 0.9, and Brycon hilarii 0.6 {mu}g g{sup -1} f.w. The average fish Hg contents were higher downstream, except for B. hilarii. In the reservoir, the average Hg content of each species was in 2005 always over the consumption limit (0.55 {mu}g total Hg g{sup -1} f.w.) recommended by WHO. Therefore, the people living around Lago Manso should be informed of the health effects of Hg, and fish consumption recommendations should be carried out. The accumulation of Hg varies widely between species as shown by the bioaccumulation factor which ranges between 5.08 and 5.59 log units. The observed variation is explained by differences in diet and trophic position with piscivorous fish exhibiting the highest mean Hg concentration, followed by carnivorous and omnivorous species. Carbon isotope analyses imply that trophic position is not the only cause of the observed differences in Hg levels between

  5. Responses of Microbial Community Composition to Temperature Gradient and Carbon Steel Corrosion in Production Water of Petroleum Reservoir

    Xiao-Xiao Li

    2017-12-01

    Full Text Available Oil reservoir production systems are usually associated with a temperature gradient and oil production facilities frequently suffer from pipeline corrosion failures. Both bacteria and archaea potentially contribute to biocorrosion of the oil production equipment. Here the response of microbial populations from the petroleum reservoir to temperature gradient and corrosion of carbon steel coupons were investigated under laboratory condition. Carbon steel coupons were exposed to production water from a depth of 1809 m of Jiangsu petroleum reservoir (China and incubated for periods of 160 and 300 days. The incubation temperatures were set at 37, 55, and 65°C to monitoring mesophilic, thermophilic and hyperthermophilic microorganisms associated with anaerobic carbon steel corrosion. The results showed that corrosion rate at 55°C (0.162 ± 0.013 mm year-1 and 37°C (0.138 ± 0.008 mm year-1 were higher than that at 65°C (0.105 ± 0.007 mm year-1, and a dense biofilm was observed on the surface of coupons under all biotic incubations. The microbial community analysis suggests a high frequency of bacterial taxa associated with families Porphyromonadaceae, Enterobacteriaceae, and Spirochaetaceae at all three temperatures. While the majority of known sulfate-reducing bacteria, in particular Desulfotignum, Desulfobulbus and Desulfovibrio spp., were predominantly observed at 37°C; Desulfotomaculum spp., Thermotoga spp. and Thermanaeromonas spp. as well as archaeal members closely related to Thermococcus and Archaeoglobus spp. were substantially enriched at 65°C. Hydrogenotrophic methanogens of the family Methanobacteriaceae were dominant at both 37 and 55°C; acetoclastic Methanosaeta spp. and methyltrophic Methanolobus spp. were enriched at 37°C. These observations show that temperature changes significantly alter the microbial community structure in production fluids and also affected the biocorrosion of carbon steel under anaerobic conditions.

  6. Carbon and oxygen dynamics on the Louisiana continental shelf: role of water column primary production and respiration

    We conducted a multi-year study of the Louisiana continental shelf (LCS) to better understand the linkages between water column net metabolism and the formation of hypoxia (dissolved oxygen respiration (R) and primary p...

  7. The elemental stoichiometry (C, Si, N, P) of the Hebrides Shelf and its role in carbon export

    Painter, S.C.; Hartman, S.E.; Kivimäe, C.; Salt, L.A.; Clargo, N.M.; Daniels, C.J.; Bozec, Y.; Daniels, L.; Allen, S.; Hemsley, V.S.; Moschonase, G.; Davidson, K.

    2017-01-01

    A detailed analysis of the internal stoichiometry of a temperate latitude shelf sea system is presented whichreveals strong vertical and horizontal gradients in dissolved nutrient and particulate concentrations and in theelemental stoichiometry of those pools. Such gradients have implications for

  8. Structural characterization and numerical simulations of flow properties of standard and reservoir carbonate rocks using micro-tomography

    Islam, Amina; Chevalier, Sylvie; Sassi, Mohamed

    2018-04-01

    With advances in imaging techniques and computational power, Digital Rock Physics (DRP) is becoming an increasingly popular tool to characterize reservoir samples and determine their internal structure and flow properties. In this work, we present the details for imaging, segmentation, as well as numerical simulation of single-phase flow through a standard homogenous Silurian dolomite core plug sample as well as a heterogeneous sample from a carbonate reservoir. We develop a procedure that integrates experimental results into the segmentation step to calibrate the porosity. We also look into using two different numerical tools for the simulation; namely Avizo Fire Xlab Hydro that solves the Stokes' equations via the finite volume method and Palabos that solves the same equations using the Lattice Boltzmann Method. Representative Elementary Volume (REV) and isotropy studies are conducted on the two samples and we show how DRP can be a useful tool to characterize rock properties that are time consuming and costly to obtain experimentally.

  9. Characteristics, stratigraphic architecture, and time framework of multi-order mixed siliciclastic and carbonate depositional sequences, outcropping Cisco Group (Late Pennsylvanian and Early Permian), Eastern Shelf, north-central Texas, USA

    Yang, Wan; Kominz, Michelle A.

    2003-01-01

    The Cisco Group on the Eastern Shelf of the Midland Basin is composed of fluvial, deltaic, shelf, shelf-margin, and slope-to-basin carbonate and siliciclastic rocks. Sedimentologic and stratigraphic analyses of 181 meter-to-decimeter-scale depositional sequences exposed in the up-dip shelf indicated that the siliciclastic and carbonate parasequences in the transgressive systems tracts (TST) are thin and upward deepening, whereas those in highstand systems tracts (HST) are thick and upward shallowing. The sequences can be subdivided into five types on the basis of principal lithofacies, and exhibit variable magnitude of facies shift corresponding to variable extents of marine transgression and regression on the shelf. The sequence stacking patterns and their regional persistence suggest a three-level sequence hierarchy controlled by eustasy, whereas local and regional changes in lithology, thickness, and sequence type, magnitude, and absence were controlled by interplay of eustasy, differential shelf subsidence, depositional topography, and pattern of siliciclastic supply. The outcropping Cisco Group is highly incomplete with an estimated 6-11% stratigraphic completeness. The average duration of deposition of the major (third-order) sequences is estimated as 67-102 ka on the up-dip shelf and increases down dip, while the average duration of the major sequence boundaries (SB) is estimated as 831-1066 ka and decreases down dip. The nondepositional and erosional hiatus on the up-dip shelf was represented by lowstand deltaic systems in the basin and slope.

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

    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

  11. Enhanced oil recovery by nitrogen and carbon dioxide injection followed by low salinity water flooding for tight carbonate reservoir: experimental approach

    Georges Lwisa, Essa; Abdulkhalek, Ashrakat R.

    2018-03-01

    Enhanced Oil Recovery techniques are one of the top priorities of technology development in petroleum industries nowadays due to the increase in demand for oil and gas which cannot be equalized by the primary production or secondary production methods. The main function of EOR process is to displace oil to the production wells by the injection of different fluids to supplement the natural energy present in the reservoir. Moreover, these injecting fluids can also help in the alterations of the properties of the reservoir like lowering the IFTs, wettability alteration, a change in pH value, emulsion formation, clay migration and oil viscosity reduction. The objective of this experiment is to investigate the residual oil recovery by combining the effects of gas injection followed by low salinity water injection for low permeability reservoirs. This is done by a series of flooding tests on selected tight carbonate core samples taken from Zakuum oil field in Abu Dhabi by using firstly low salinity water as the base case and nitrogen & CO2injection followed by low salinity water flooding at reservoir conditions of pressure and temperature. The experimental results revealed that a significant improvement of the oil recovery is achieved by the nitrogen injection followed by the low salinity water flooding with a recovery factor of approximately 24% of the residual oil.

  12. Dry Stream Reaches in Carbonate Terranes: Surface Indicators of Ground-Water Reservoirs

    Brahana, J.V.; Hollyday, E.F.

    1988-01-01

    In areas where dry stream reaches occur, subsurface drainage successfully competes with surface drainage, and sheet-like dissolution openings have developed parallel to bedding creating the ground-water reservoir. Union Hollow in south-central Tennessee is the setting for a case study that illustrates the application of the dry stream reach technique. In this technique, dry stream reach identification is based on two types of readily acquired information: remotely sensed black and white infrared aerial photography; and surface reconnaissance of stream channel characteristics. Test drilling in Union Hollow subsequent to identification of the dry reach proved that a localized ground-water reservoir was present.

  13. Synchronous response of sedimentary organic carbon accumulation on the inner shelf of the East China Sea to the water impoundment of Three Gorges and Gezhouba Dams

    Lin, Jia; Zhu, Qing; Hong, Yuehui; Yuan, Lirong; Liu, Jinzhong; Xu, Xiaoming; Wang, Jianghai

    2018-01-01

    Coastal seas, located between continents and the open ocean, are an important active carbon pool. The sedimentary total organic carbon (TOC) in these areas is a mixture of terrestrial and marine sources, and can be a powerful proxy for tracing natural processes and human activities. In this study, one fine-grained sediment core (DH5-1) from the inner shelf of the East China Sea was systematically analyzed for TOC and black carbon (BC) contents and TOC stable carbon isotope ratios (δ13C). By combining these data with 210Pb dating, an improved carbon correction model and a two end-member mixing model, we reconstructed century-scale high-resolution sequences of corrected TOC, terrestrial TOC and marine TOC contents and identified two carbon depletion events in the DH5-1 record. The two events, shown as two minima in the TOC profiles, correspond temporally to 1985-1987 AD and 2003-2006 AD, which exactly matches the water impoundment of the Gezhouba Dam and Three Gorges Dam, respectively. In addition, the variations in TOC contents and δ13C values before, during or after the minima demonstrate a relationship between the depletion events and water impoundment of the dams on the Changjiang River. The TOC reductions may represent synchronous responses of sedimentary TOC and resultant ecological effects on the inner shelf of the East China Sea to the water impoundment of the dams. These new TOC records reflect the interaction between natural and anthropogenic processes and, accordingly, provide a deep insight and important references for assessing marine ecological effects resulting from water impoundment of largescale dams.

  14. Development of infill drilling recovery models for carbonates reservoirs using neural networks and multivariate statistical as a novel method

    Soto, R; Wu, Ch. H; Bubela, A M

    1999-01-01

    This work introduces a novel methodology to improve reservoir characterization models. In this methodology we integrated multivariate statistical analyses, and neural network models for forecasting the infill drilling ultimate oil recovery from reservoirs in San Andres and Clearfork carbonate formations in west Texas. Development of the oil recovery forecast models help us to understand the relative importance of dominant reservoir characteristics and operational variables, reproduce recoveries for units included in the database, forecast recoveries for possible new units in similar geological setting, and make operational (infill drilling) decisions. The variety of applications demands the creation of multiple recovery forecast models. We have developed intelligent software (Soto, 1998), oilfield intelligence (01), as an engineering tool to improve the characterization of oil and gas reservoirs. 01 integrates neural networks and multivariate statistical analysis. It is composed of five main subsystems: data input, preprocessing, architecture design, graphic design, and inference engine modules. One of the challenges in this research was to identify the dominant and the optimum number of independent variables. The variables include porosity, permeability, water saturation, depth, area, net thickness, gross thickness, formation volume factor, pressure, viscosity, API gravity, number of wells in initial water flooding, number of wells for primary recovery, number of infill wells over the initial water flooding, PRUR, IWUR, and IDUR. Multivariate principal component analysis is used to identify the dominant and the optimum number of independent variables. We compared the results from neural network models with the non-parametric approach. The advantage of the non-parametric regression is that it is easy to use. The disadvantage is that it retains a large variance of forecast results for a particular data set. We also used neural network concepts to develop recovery

  15. Computer Modeling of the Displacement Behavior of Carbon Dioxide in Undersaturated Oil Reservoirs

    Ju Binshan

    2015-11-01

    Full Text Available The injection of CO2 into oil reservoirs is performed not only to improve oil recovery but also to store CO2 captured from fuel combustion. The objective of this work is to develop a numerical simulator to predict quantitatively supercritical CO2 flooding behaviors for Enhanced Oil Recovery (EOR. A non-isothermal compositional flow mathematical model is developed. The phase transition diagram is designed according to the Minimum Miscibility Pressure (MMP and CO2 maximum solubility in oil phase. The convection and diffusion of CO2 mixtures in multiphase fluids in reservoirs, mass transfer between CO2 and crude and phase partitioning are considered. The governing equations are discretized by applying a fully implicit finite difference technique. Newton-Raphson iterative technique was used to solve the nonlinear equation systems and a simulator was developed. The performances of CO2 immiscible and miscible flooding in oil reservoirs are predicted by the new simulator. The distribution of pressure and temperature, phase saturations, mole fraction of each component in each phase, formation damage caused by asphaltene precipitation and the improved oil recovery are predicted by the simulator. Experimental data validate the developed simulator by comparison with simulation results. The applications of the simulator in prediction of CO2 flooding in oil reservoirs indicate that the simulator is robust for predicting CO2 flooding performance.

  16. Patterns in stable isotope values of nitrogen and carbon in particulate matter from the Northwest Atlantic Continental Shelf, from the Gulf of Maine to Cape Hatteras

    Autumn Oczkowski

    2016-12-01

    Full Text Available Stable isotope measurements of nitrogen and carbon (δ15N, δ13C are often used to characterize estuarine, nearshore, and open ocean ecosystems. Reliable information about the spatial distribution of base-level stable isotope values, often represented by primary producers, is critical to interpreting values in these ecosystems. While base-level isotope data are generally readily available for estuaries, nearshore coastal waters, and the open ocean, the continental shelf is less studied. To address this, and as a first step towards developing a surrogate for base-level isotopic signature in this region, we collected surface and deep water samples from the United States’ eastern continental shelf in the Western Atlantic Ocean, from the Gulf of Maine to Cape Hatteras, periodically between 2000 and 2013. During the study, particulate matter δ15N values ranged from 0.8 to 17.4 ‰, and δ13C values from -26.4 to -15.6 ‰ over the region. We used spatial autocorrelation analysis and random forest modeling to examine the spatial trends and potential environmental drivers of the stable isotope values. We observed general trends towards lower values for both nitrogen and carbon isotopes at the seaward edge of the shelf. Conversely, higher δ15N and δ13C values were observed on the landward edge of the shelf, in particular in the southern portion of the sampling area. Across all sites, the magnitude of the difference between the δ15N of subsurface and surface particulate matter (PM significantly increased with water depth (r2 = 0.41, df = 35, p < 0.001, while δ13C values did not change. There were significant positive correlation between δ15N and δ13C values for surface PM in each of the three marine ecoregions that make up the study area. Stable isotope dynamics on the shelf can inform both nearshore and open ocean research efforts, reflecting regional productivity patterns and, even possibly, large-scale climate fluctuations.

  17. Impact of stylolitization on diagenesis of a Lower Cretaceous carbonate reservoir from a giant oilfield, Abu Dhabi, United Arab Emirates

    Paganoni, Matteo; Al Harthi, Amena; Morad, Daniel; Morad, Sadoon; Ceriani, Andrea; Mansurbeg, Howri; Al Suwaidi, Aisha; Al-Aasm, Ihsan S.; Ehrenberg, Stephen N.; Sirat, Manhal

    2016-04-01

    Bed-parallel stylolites are a widespread diagenetic feature in Lower Cretaceous limestone reservoirs, Abu Dhabi, United Arab Emirates (UAE). Diagenetic calcite, dolomite, kaolin and small amounts of pyrite, fluorite, anhydrite and sphalerite occur along and in the vicinity of the stylolites. Petrographic observations, negative δ18OVPDB, fluid inclusion microthermometry, and enrichment in 87Sr suggest that these cements have precipitated from hot basinal brines, which migrated along the stylolites and genetically related microfractures (tension gashes). Fluid migration was presumably related to lateral tectonic compression events related to the foreland basin formation. The low solubility of Al3 + in formation waters suggests that kaolin precipitation was linked to derivation of organic acids during organic matter maturation, probably in siliciclastic source rocks. The mass released from stylolitization was presumably re-precipitated as macro- and microcrystalline calcite cement in the host limestones. The flanks of the oilfield (water zone) display more frequent presence and higher amplitude of stylolites, lower porosity and permeability, higher homogenization temperatures and more radiogenic composition of carbonates compared to the crest (oil zone). This indicates that oil emplacement retards diagenesis. This study demonstrates that stylolitization plays a crucial role in fluid flow and diagenesis of carbonate reservoirs during basin evolution.

  18. The equivalent pore aspect ratio as a tool for pore type prediction in carbonate reservoirs

    FOURNIER , François; Pellerin , Matthieu; Villeneuve , Quentin; Teillet , Thomas; Hong , Fei; Poli , Emmanuelle; Borgomano , Jean; Léonide , Philippe; Hairabian , Alex

    2018-01-01

    International audience; The equivalent pore aspect ratios (EPAR) provide a tool to detect pore types by combining P-and S-wave velocities, porosity, bulk density and mineralogical composition of carbonate rocks. The integration of laboratory measurements, well log data and petrographic analysis of 468 carbonate samples from various depositional and diagenetic settings (Lower Cretaceous pre-salt non-marine carbonates from offshore Brazil, Lower Cretaceous shallow-water platform carbonates from...

  19. High oxygen and high carbon dioxide modified atmospheres for shelf-life extension of minimally processed carrots

    Amanatidou, A.; Slump, R.A.; Gorris, L.G.M.; Smid, E.J.

    2000-01-01

    The impact of high O2 + high CO2 modified atmospheres (MA), on the preservation of minimally processed carrots was studied. A combination of 50% O2 + 30% CO2 prolonged the shelf life of sliced carrots compared to storage in air by 2 to 3 d. When the carrots received a pre-treatment with a 0.1%

  20. Quantifying Sources and Fluxes of Aquatic Carbon in U.S. Streams and Reservoirs Using Spatially Referenced Regression Models

    Boyer, E. W.; Smith, R. A.; Alexander, R. B.; Schwarz, G. E.

    2004-12-01

    Organic carbon (OC) is a critical water quality characteristic in riverine systems that is an important component of the aquatic carbon cycle and energy balance. Examples of processes controlled by OC interactions are complexation of trace metals; enhancement of the solubility of hydrophobic organic contaminants; formation of trihalomethanes in drinking water; and absorption of visible and UV radiation. Organic carbon also can have indirect effects on water quality by influencing internal processes of aquatic ecosystems (e.g. photosynthesis and autotrophic and heterotrophic activity). The importance of organic matter dynamics on water quality has been recognized, but challenges remain in quantitatively addressing OC processes over broad spatial scales in a hydrological context. In this study, we apply spatially referenced watershed models (SPARROW) to statistically estimate long-term mean-annual rates of dissolved- and total- organic carbon export in streams and reservoirs across the conterminous United States. We make use of a GIS framework for the analysis, describing sources, transport, and transformations of organic matter from spatial databases providing characterizations of climate, land use, primary productivity, topography, soils, and geology. This approach is useful because it illustrates spatial patterns of organic carbon fluxes in streamflow, highlighting hot spots (e.g., organic-rich environments in the southeastern coastal plain). Further, our simulations provide estimates of the relative contributions to streams from allochthonous and autochthonous sources. We quantify surface water fluxes of OC with estimates of uncertainty in relation to the overall US carbon budget; our simulations highlight that aquatic sources and sinks of OC may be a more significant component of regional carbon cycling than was previously thought. Further, we are using our simulations to explore the potential role of climate and other changes in the terrestrial environment on

  1. Capillary pressure - saturation relations for supercritical CO2 and brine: Implications for capillary/residual trapping in carbonate reservoirs during geologic carbon sequestration

    Wang, S.; Tokunaga, T. K.

    2014-12-01

    In geologic carbon sequestration (GCS), data on capillary pressure (Pc) - saturation (Sw) relations are routinely needed to appraise reservoir processes. Capillarity and its hysteresis have been often experimentally studied in oil-water, gas-water and three phase gas-oil-water systems, but fewer works have been reported on scCO2-water under in-situ reservoir conditions. Here, Pc-Sw relations of supercritical (sc) CO2 displacing brine, and brine rewetting the porous medium to trap scCO2 were studied to understand CO2 transport and trapping behavior in carbonate reservoirs under representative reservoir conditions. High-quality drainage and imbibition (and associated capillary pressure hysteresis) curves were measured under elevated temperature and pressure (45 ºC, 8.5 and 12 MPa) for scCO2-brine as well as at room temperature and pressure (23 ºC, 0.1 MPa) for air-brine in unconsolidated limestone and dolomite sand columns using newly developed semi-automated multistep outflow-inflow porous plate apparatus. Drainage and imbibition curves for scCO2-brine deviated from the universal scaling curves for hydrophilic interactions (with greater deviation under higher pressure) and shifted to lower Pc than predicted based on interfacial tension (IFT) changes. Augmented scaling incorporating differences in IFT and contact angle improved the scaling results but the scaled curves still did not converge onto the universal curves. Equilibrium residual trapping of the nonwetting phase was determined at Pc =0 during imbibition. The capillary-trapped amounts of scCO2 were significantly larger than for air. It is concluded that the deviations from the universal capillary scaling curves are caused by scCO2-induced wettability alteration, given the fact that pore geometry remained constant and IFT is well constrained. In-situ wettability alteration by reactive scCO2 is of critical importance and must be accounted for to achieve reliable predictions of CO2 behavior in GCS reservoirs.

  2. Uncovering the Minor Contribution of Land-Cover Change in Upland Forests to the Net Carbon Footprint of a Boreal Hydroelectric Reservoir.

    Dessureault, Pierre-Luc; Boucher, Jean-François; Tremblay, Pascal; Bouchard, Sylvie; Villeneuve, Claude

    2015-07-01

    Hydropower in boreal conditions is generally considered the energy source emitting the least greenhouse gas per kilowatt-hour during its life cycle. The purpose of this study was to assess the relative contribution of the land-use change on the modification of the carbon sinks and sources following the flooding of upland forested territories to create the Eastmain-1 hydroelectric reservoir in Quebec's boreal forest using Carbon Budget Model of the Canadian Forest Sector. Results suggest a carbon sink loss after 100 yr of 300,000 ± 100,000 Mg CO equivalents (COe). A wildfire sensitivity analysis revealed that the ecosystem would have acted as a carbon sink as long as carbon flux estimate resulted in emissions of 4 ± 2 g COe kWh as a contribution to the carbon footprint calculation, one-eighth what was obtained in a recent study that used less precise and less sensitive estimates. Consequently, this study significantly reduces the reported net carbon footprint of this reservoir and reveals how negligible the relative contribution of the land-use change in upland forests to the total net carbon footprint of a hydroelectric reservoir in the boreal zone can be. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  3. Geochemical monitoring using noble gases and carbon isotopes: study of a natural reservoir; Monitoring geochimique par couplage entre les gaz rares et les isotopes du carbone: etude d'un reservoir naturel

    Jeandel, E

    2008-12-15

    To limit emissions of greenhouse gases in the atmosphere, CO{sub 2} geological sequestration appears as a solution in the fight against climate change. The development of reliable monitoring tools to ensure the sustainability and the safety of geological storage is a prerequisite for the implementation of such sites. In this framework, a geochemical method using noble gas and carbon isotopes geochemistry has been tested on natural and industrial analogues. The study of natural analogues from different geological settings showed systematic behaviours of the geochemical parameters, depending on the containment sites, and proving the effectiveness of these tools in terms of leak detection and as tracers of the behaviour of CO{sub 2}. Moreover, an experience of geochemical tracing on a natural gas storage has demonstrated that it is possible to identify the physical-chemical processes taking place in the reservoir to a human time scale, increasing interest in the proposed tool and providing general information on its use. (author)

  4. The effect of carbon dioxide on the shelf life of ready-to-eat shredded chicken breast stored under refrigeration.

    Rodriguez, M B R; Junior, C A Conte; Carneiro, C S; Franco, R M; Mano, S B

    2014-01-01

    The objective of the present study was to determine the shelf life of ready-to-eat cooked chicken breast fillets (shredded) stored in atmospheres that were modified with different concentrations of CO2 and to establish a relationship between the concentration of this gas and bacterial growth. The samples were divided into 7 groups with different packaging conditions: aerobiosis, vacuum, and 10, 30, 50, 70, and 90% CO2 (with the remaining volume filled with N2). All of the samples were stored at 4 ± 2°C for 28 d. During this period, pH tests and counts of aerobic heterotrophic mesophyll bacteria (AHMB), aerobic heterotrophic psychotropic bacteria (AHPB), Enterobacteriaceae, and lactic acid bacteria (LAB) were performed, and the gas compositions of the packaging atmospheres were verified. The pH of the aerobic packages increased during storage. However, the other treatments resulted in the opposite trend, with the CO2 concentration decreasing over the first 24 h and then remaining constant until the end of experiment. A gradual increase in the AHMB, AHPB, Enterobacteriaceae, and LAB counts was observed during storage; this increase was faster in the meat that was packed under aerobiosis conditions than in the other treatments. The treatments with a CO2 concentration above 10% exhibited lower Enterobacteriaceae growth, whereas LAB growth was discrete in all of the treatments, independent of the CO2 concentration. The shelf life of the samples packed with 90% CO2 was 28 d. Based on the AHMB and AHPB counts, the shelf life was 3 times longer than for the samples packed under aerobiosis conditions (9 d). The increased package CO2 concentration caused a reduction in the growth rate of the examined bacteria (r = 0.99), and treatment with 90% CO2 appears promising as a method with which to increase the product's shelf life.

  5. High primary production contrasts with intense carbon emission in a eutrophic tropical reservoir

    Almeida, Rafael M.; Nóbrega, Gabriel N.; Junger, Pedro C.; Figueiredo, Aline V.; Andrade, Anízio S.; Moura, de Caroline G.B.; Tonetta, Denise; Oliveira, Ernandes S.; Araújo, Fabiana; Rust, Felipe; Piñeiro-Guerra, Juan M.; Mendonça, Jurandir R.; Medeiros, Leonardo R.; Pinheiro, Lorena; Miranda, Marcela; Costa, Mariana R.A.; Melo, Michaela L.; Nobre, Regina L.G.; Benevides, Thiago; Roland, Fábio; Klein, de Jeroen; Barros, Nathan O.; Mendonça, Raquel; Becker, Vanessa; Huszar, Vera L.M.; Kosten, Sarian

    2016-01-01

    Recent studies from temperate lakes indicate that eutrophic systems tend to emit less carbon dioxide (CO2) and bury more organic carbon (OC) than oligotrophic ones, rendering them CO2 sinks in some cases. However, the scarcity of data from tropical systems is critical for a

  6. Geology and biology of the "Sticky Grounds," shelf-margin carbonate mounds, and mesophotic ecosystem in the eastern Gulf of Mexico

    Locker, Stanley D.; Reed, John K.; Farrington, Stephanie; Harter, Stacey; Hine, Albert C.; Dunn, Shane

    2016-01-01

    Shelf-margin carbonate mounds in water depths of 116–135 m in the eastern Gulf of Mexico along the central west Florida shelf were investigated using swath bathymetry, side-scan sonar, sub-bottom imaging, rock dredging, and submersible dives. These enigmatic structures, known to fisherman as the “Sticky Grounds”, trend along slope, are 5–15 m in relief with base diameters of 5–30 m, and suggest widespread potential for mesophotic reef habitat along the west Florida outer continental shelf. Possible origins are sea-level lowstand coral patch reefs, oyster reefs, or perhaps more recent post-lowstand biohermal development. Rock dredging recovered bioeroded carbonate-rock facies comprised of bored and cemented bioclastics. Rock sample components included calcified worm tubes, pelagic sediment, and oysters normally restricted to brackish nearshore areas. Several reef sites were surveyed at the Sticky Grounds during a cruise in August 2010 with the R/V Seward Johnson using the Johnson-Sea-Link II submersible to ground truth the swath-sonar maps and to quantify and characterize the benthic habitats, benthic macrofauna, fish populations, and coral/sponge cover. This study characterizes for the first time this mesophotic reef ecosystem and associated fish populations, and analyzes the interrelationships of the fish assemblages, benthic habitats and invertebrate biota. These highly eroded rock mounds provide extensive hard-bottom habitat for reef invertebrate species as well as essential fish habitat for reef fish and commercially/recreationally important fish species. The extent and significance of associated living resources with these bottom types is particularly important in light of the 2010 Deepwater Horizon oil spill in the northeastern Gulf and the proximity of the Loop Current. Mapping the distribution of these mesophotic-depth ecosystems is important for quantifying essential fish habitat and describing benthic resources. These activities can improve

  7. Geologic storage of carbon dioxide and enhanced oil recovery. I. Uncertainty quantification employing a streamline based proxy for reservoir flow simulation

    Kovscek, A.R.; Wang, Y.

    2005-01-01

    Carbon dioxide (CO 2 ) is already injected into a limited class of reservoirs for oil recovery purposes; however, the engineering design question for simultaneous oil recovery and storage of anthropogenic CO 2 is significantly different from that of oil recovery alone. Currently, the volumes of CO 2 injected solely for oil recovery are minimized due to the purchase cost of CO 2 . If and when CO 2 emissions to the atmosphere are managed, it will be necessary to maximize simultaneously both economic oil recovery and the volumes of CO 2 emplaced in oil reservoirs. This process is coined 'cooptimization'. This paper proposes a work flow for cooptimization of oil recovery and geologic CO 2 storage. An important component of the work flow is the assessment of uncertainty in predictions of performance. Typical methods for quantifying uncertainty employ exhaustive flow simulation of multiple stochastic realizations of the geologic architecture of a reservoir. Such approaches are computationally intensive and thereby time consuming. An analytic streamline based proxy for full reservoir simulation is proposed and tested. Streamline trajectories represent the three-dimensional velocity field during multiphase flow in porous media and so are useful for quantifying the similarity and differences among various reservoir models. The proxy allows rational selection of a representative subset of equi-probable reservoir models that encompass uncertainty with respect to true reservoir geology. The streamline approach is demonstrated to be thorough and rapid

  8. Study of ionically modified water performance in carbonate reservoir system by multivariate data analysis

    Sohal, Muhammad Adeel Nassar; Kucheryavskiy, Sergey V.; Thyne, Geoffrey

    2017-01-01

    the critical mechanisms at the pore scale. Better pore scale physico-chemical understanding will guide to formulate accurate reservoir-scale models. This paper presents a comprehensive meta-analysis of the proposed mechanisms using multivariate data analysis. Detailed review of the subject, including...... mechanisms with supporting and contradictory evidence has been presented by Sohal et al. (2016). In this study, the significance of each contributing factor to EOR was quantified and subjected to rigorous multivariate statistical analysis. The analysis was limited because there is no uniform methodology...

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

    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

  10. How the rock fabrics can control the physical properties - A contribution to the understanding of carbonate reservoirs

    Duerrast, H.; Siegesmund, S. [Goettingen Univ. (Germany)

    1998-12-31

    The correlation between microfabrics and physical properties will be illustrated in detail on three dolomitic carbonate reservoir rocks with different porosity. For this study core segments from the Zechstein Ca2-layer (Permian) of the Northwest German Basin were kindly provided by the Preussag Energie GmbH, Lingen. The mineral composition was determined by using the X-ray diffraction method. Petrographic and detailed investigation of the microfabrics, including the distribution and orientation of the cracks were done macroscopally (core segments) and microscopally with the optical microscope and the Scanning Electron Microscope (thin sections in three orthogonally to each other oriented directions). Different kinds of petrophysical measurements were carried out, e.g. porosity, permeability, electrical conductivity, seismic velocities. (orig.)

  11. Risk Assessment of Carbon Sequestration into A Naturally Fractured Reservoir at Kevin Dome, Montana

    Nguyen, Minh [Univ. of Wyoming, Laramie, WY (United States); Onishi, Tsubasa [Texas A & M Univ., College Station, TX (United States); Carey, James William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Will, Bob [Schlumberger, Houston, TX (United States); Zaluski, Wade [Schlumberger, Houston, TX (United States); Bowen, David [Montana State Univ., Bozeman, MT (United States); DeVault, Brian [Vecta Oil and Gas, Dallas, TX (United States); Duguid, Andrew [Battelle Memorial Inst., Columbus, OH (United States); Spangler, Lee [Montana State Univ., Bozeman, MT (United States); Stauffer, Philip H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-12-22

    In this report, we describe risk assessment work done using the National Risk Assessment Partnership (NRAP) applied to CO2 storage at Kevin Dome, Montana. Geologic CO2 sequestration in saline aquifers poses certain risks including CO2/brine leakage through wells or non-sealing faults into groundwater or to the land surface. These risks are difficult to quantify due to data availability and uncertainty. One solution is to explore the consequences of these limitations by running large numbers of numerical simulations on the primary CO2 injection reservoir, shallow reservoirs/aquifers, faults, and wells to assess leakage risks and uncertainties. However, a large number of full-physics simulations is usually too computationally expensive. The NRAP integrated assessment model (NRAP-IAM) uses reduced order models (ROMs) developed from full-physics simulations to address this issue. A powerful stochastic framework allows NRAPIAM to explore complex interactions among many uncertain variables and evaluate the likely performance of potential sequestration sites.

  12. Key Factors for Determining Risk of Groundwater Impacts Due to Leakage from Geologic Carbon Sequestration Reservoirs

    Carroll, Susan [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Keating, Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mansoor, Kayyum [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dai, Zhenue [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sun, Yunwei [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Trainor-Guitton, Whitney [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brown, Chris [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bacon, Diana [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-01-06

    The National Risk Assessment Partnership (NRAP) is developing a science-based toolset for the analysis of potential impacts to groundwater chemistry from CO2 injection (www.netldoe.gov/nrap). The toolset adopts a stochastic approach in which predictions address uncertainties in shallow underwater and leakage scenarios. It is derived from detailed physics and chemistry simulation results that are used to train more computationally efficient models,l referred to here as reduced-order models (ROMs), for each component system. In particular, these tools can be used to help regulators and operators understand the expected sizes and longevity of plumes in pH, TDS, and dissolved metals that could result from a leakage of brine and/or CO2 from a storage reservoir into aquifers. This information can inform, for example, decisions on monitoring strategies that are both effective and efficient. We have used this approach to develop predictive reduced-order models for two common types of reservoirs, but the approach could be used to develop a model for a specific aquifer or other common types of aquifers. In this paper we describe potential impacts to groundwater quality due to CO2 and brine leakage, discuss an approach to calculate thresholds under which "no impact" to groundwater occurs, describe the time scale for impact on groundwater, and discuss the probability of detecting a groundwater plume should leakage occur.

  13. Summertime calcium carbonate undersaturation in shelf waters of the western Arctic Ocean – how biological processes exacerbate the impact of ocean acidification

    N. R. Bates

    2013-08-01

    Full Text Available The Arctic Ocean accounts for only 4% of the global ocean area, but it contributes significantly to the global carbon cycle. Recent observations of seawater CO2-carbonate chemistry in shelf waters of the western Arctic Ocean, primarily in the Chukchi Sea, from 2009 to 2011 indicate that bottom waters are seasonally undersaturated with respect to calcium carbonate (CaCO3 minerals, particularly aragonite. Nearly 40% of sampled bottom waters on the shelf have saturation states less than one for aragonite (i.e., Ωaragonite 3-secreting organisms, while 80% of bottom waters present had Ωaragonite values less than 1.5. Our observations indicate seasonal reduction of saturation states (Ω for calcite (Ωcalcite and aragonite (Ωaragonite in the subsurface in the western Arctic by as much as 0.8 and 0.5, respectively. Such data indicate that bottom waters of the western Arctic shelves were already potentially corrosive for biogenic and sedimentary CaCO3 for several months each year. Seasonal changes in Ω are imparted by a variety of factors such as phytoplankton photosynthesis, respiration/remineralization of organic matter and air–sea gas exchange of CO2. Combined, these processes either increase or enhance in surface and subsurface waters, respectively. These seasonal physical and biological processes also act to mitigate or enhance the impact of Anthropocene ocean acidification (OA on Ω in surface and subsurface waters, respectively. Future monitoring of the western Arctic shelves is warranted to assess the present and future impact of ocean acidification and seasonal physico-biogeochemical processes on Ω values and Arctic marine ecosystems.

  14. Play-level distributions of estimates of recovery factors for a miscible carbon dioxide enhanced oil recovery method used in oil reservoirs in the conterminous United States

    Attanasi, E.D.; Freeman, P.A.

    2016-03-02

    In a U.S. Geological Survey (USGS) study, recovery-factor estimates were calculated by using a publicly available reservoir simulator (CO2 Prophet) to estimate how much oil might be recovered with the application of a miscible carbon dioxide (CO2) enhanced oil recovery (EOR) method to technically screened oil reservoirs located in onshore and State offshore areas in the conterminous United States. A recovery factor represents the percentage of an oil reservoir’s original oil in place estimated to be recoverable by the application of a miscible CO2-EOR method. The USGS estimates were calculated for 2,018 clastic and 1,681 carbonate candidate reservoirs in the “Significant Oil and Gas Fields of the United States Database” prepared by Nehring Associates, Inc. (2012).

  15. An Efficient Upscaling Procedure Based on Stokes-Brinkman Model and Discrete Fracture Network Method for Naturally Fractured Carbonate Karst Reservoirs

    Qin, Guan

    2010-01-01

    Naturally-fractured carbonate karst reservoirs are characterized by various-sized solution caves that are connected via fracture networks at multiple scales. These complex geologic features can not be fully resolved in reservoir simulations due to the underlying uncertainty in geologic models and the large computational resource requirement. They also bring in multiple flow physics which adds to the modeling difficulties. It is thus necessary to develop a method to accurately represent the effect of caves, fractures and their interconnectivities in coarse-scale simulation models. In this paper, we present a procedure based on our previously proposed Stokes-Brinkman model (SPE 125593) and the discrete fracture network method for accurate and efficient upscaling of naturally fractured carbonate karst reservoirs.

  16. Dynamic Pore-Scale Imaging of Reactive Transport in Heterogeneous Carbonates at Reservoir Conditions Across Multiple Dissolution Regimes

    Menke, H. P.; Bijeljic, B.; Andrew, M. G.; Blunt, M. J.

    2014-12-01

    Sequestering carbon in deep geologic formations is one way of reducing anthropogenic CO2 emissions. When supercritical CO2 mixes with brine in a reservoir, the acid generated has the potential to dissolve the surrounding pore structure. However, the magnitude and type of dissolution are condition dependent. Understanding how small changes in the pore structure, chemistry, and flow properties affect dissolution is paramount for successful predictive modelling. Both 'Pink Beam' synchrotron radiation and a Micro-CT lab source are used in dynamic X-ray microtomography to investigate the pore structure changes during supercritical CO2 injection in carbonate rocks of varying heterogeneity at high temperatures and pressures and various flow-rates. Three carbonate rock types were studied, one with a homogeneous pore structure and two heterogeneous carbonates. All samples are practically pure calcium carbonate, but have widely varying rock structures. Flow-rate was varied in three successive experiments by over an order of magnitude whlie keeping all other experimental conditions constant. A 4-mm carbonate core was injected with CO2-saturated brine at 10 MPa and 50oC. Tomographic images were taken at 30-second to 20-minute time-resolutions during a 2 to 4-hour injection period. A pore network was extracted using a topological analysis of the pore space and pore-scale flow modelling was performed directly on the binarized images with connected pathways and used to track the altering velocity distributions. Significant differences in dissolution type and magnitude were found for each rock type and flowrate. At the highest flow-rates, the homogeneous carbonate was seen to have predominately uniform dissolution with minor dissolution rate differences between the pores and pore throats. Alternatively, the heterogeneous carbonates which formed wormholes at high flow rates. At low flow rates the homogeneous rock developed wormholes, while the heterogeneous samples showed evidence

  17. Nitrogen and carbon limitation of planktonic primary production and phytoplankton–bacterioplankton coupling in ponds on the McMurdo Ice Shelf, Antarctica

    Sorrell, Brian K; Safi, Karl; Hawes, Ian

    2013-01-01

    We compared planktonic primary and secondary production across twenty meltwater ponds on the surface of the McMurdo Ice Shelf in January 2007, including some ponds with basal brines created by meromictic stratification. Primary production ranged from 1.07 to 65.72 mgC m −3 h −1 in surface waters. In stratified ponds primary production was always more than ten times higher in basal brines than in the corresponding mixolimnion. Regression tree analysis (r 2 = 0.80) identified inorganic nitrogen (as NH 4 + ) as the main factor limiting planktonic primary production. However, there was also evidence of inorganic carbon co-limitation of photosynthesis in some of the more oligotrophic waters. Neither C nor N limited carbon fixation at [NH 4 –N] > 50 mg m −3 , with photoinhibition the factor most likely limiting photosynthesis under such conditions. Primary production was the only factor significantly correlated to bacterial production and the relationship (r 2 = 0.56) was non-linear. Nitrogen limitation and tight coupling of planktonic primary and bacterial production is surprising in these ponds, as all have large pools of dissolved organic carbon (1.2–260 g m −3 ) and organic nitrogen (all >130 mg m −3 ). The dissolved pools of organic carbon and nitrogen appear to be recalcitrant and bacterial production to be constrained by limited release of labile organics from phytoplankton. (letter)

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

    Ernest A. Mancini

    2004-02-25

    The University of Alabama, in cooperation with Texas A&M University, McGill University, Longleaf Energy Group, Strago Petroleum Corporation, and Paramount Petroleum Company, has undertaken 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 goal 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. Geoscientific reservoir property, geophysical seismic attribute, petrophysical property, and engineering property characterization has shown that reef (thrombolite) and shoal reservoir lithofacies developed on the flanks of high-relief crystalline basement paleohighs (Vocation Field example) and on the crest and flanks of low-relief crystalline basement paleohighs (Appleton Field example). The reef thrombolite lithofacies have higher reservoir quality than the shoal lithofacies due to overall higher permeabilities and greater interconnectivity. Thrombolite dolostone flow units, which are dominated by dolomite intercrystalline and vuggy pores, are characterized by a pore system comprised of a higher percentage of large-sized pores and larger pore throats. Rock-fluid interactions (diagenesis) studies have shown that although the primary control on

  19. Exploring a carbonate reef reservoir - nuclear magnetic resonance and computed microtomography confronted with narrow channel and fracture porosity

    Fheed, Adam; Krzyżak, Artur; Świerczewska, Anna

    2018-04-01

    The complexity of hydrocarbon reservoirs, comprising numerous moulds, vugs, fractures and channel porosity, requires a specific set of methods to be used in order to obtain plausible petrophysical information. Both computed microtomography (μCT) and nuclear magnetic resonance (NMR) are nowadays commonly utilized in pore space investigation. The principal aim of this paper is to propose an alternative, quick and easily executable approach, enabling a thorough understanding of the complicated interiors of the carbonate hydrocarbon reservoir rocks. Highly porous and fractured Zechstein bioclastic packstones from the Brońsko Reef, located in West Poland were studied. Having examined 20 thin sections coming from two different well bores, 10 corresponding core samples were subjected to both μCT and NMR experiments. After a preliminary μCT-based image analysis, 9.4 [T] high-field zero echo time (ZTE) imaging, using a very short repetition time (RT) of 2 [μs] was conducted. Taking into consideration the risk of internal gradients' generation, the reliability of ZTE was verified by 0.6 [T] Single Point Imaging (SPI), during which such a phenomenon is much less probable. Both narrow channels and fractures of different apertures appeared to be common within the studied rocks. Their detailed description was therefore undertaken based on an additional tool - the spatially-resolved 0.05 [T] T2 profiling. According to the obtained results, ZTE seems to be especially suitable for studying porous and fractured carbonate rocks, as little disturbance to the signal appears. This can be confirmed by the SPI, indicating the negligible impact of the internal gradients on the registered ZTE images. Both NMR imaging and μCT allowed for locating the most porous intervals including well-developed mouldic porosity, as well as the contrasting impermeable structures, such as the stylolites and anhydrite veins. The 3D low-field profiling, in turn, showed the fracture aperture variations

  20. Types and characteristics of carbonate reservoirs and their implication on hydrocarbon exploration: A case study from the eastern Tarim Basin, NW China

    Shiwei Huang

    2017-02-01

    Full Text Available Carbonate rocks are deposited in the Ordovician, Cambrian, and Sinian of eastern Tarim Basin with a cumulative maximum thickness exceeding 2000 m. They are the main carriers of oil and gas, and a great deal of natural gas has been found there in the past five years. Based on lithofacies and reservoir differences, natural gas exploration domains of eastern Tarim Basin can be classified into five types: Ordovician platform limestone; Ordovician platform dolomite; Cambrian platform margin mound shoal; Cambrian slope gravity flow deposits, and; Sinian dolomite. Carbonate reservoir characteristics of all the types were synthetically analyzed through observation on drilling core and thin sections, porosity and permeability measurement, and logging data of over 10 drilling wells. We find distribution of part of good fracture and cave reservoir in carbonate platform limestone of Ordovician. In the Ordovician, platform facies dolomite is better than limestone, and in the Cambrian, platform margin mound shoal dolomite has large stacking thickness. Good quality and significantly thick carbonate gravity deposit flow can be found in the Cambrian slope, and effective reservoir has also been found in Sinian dolomite. Commercial gas has been found in the limestone and dolomite of Ordovician in Shunnan and Gucheng areas. Exploration experiences from these two areas are instructive, enabling a deeper understanding of this scene.

  1. Heterogeneous Shallow-Shelf Carbonate Buildups in the Paradox Basin, Utah and Colorado: Targets for Increased Oil Production and Reserves Using Horizontal Drilling Techniques

    Thomas C. Chidsey; Kevin McClure; Craig D. Morgan

    2003-10-05

    The Paradox Basin of Utah, Colorado, Arizona, and New Mexico contains nearly 100 small oil fields producing from carbonate buildups within the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to 10 wells with primary production ranging from 700,000 to 2,000,000 barrels (111,300-318,000 m{sup 3}) of oil per field and a 15 to 20 percent recovery rate. At least 200 million barrels (31.8 million m{sup 3}) of oil will not be recovered from these small fields because of inefficient recovery practices and undrained heterogeneous reservoirs. Several fields in southeastern Utah and southwestern Colorado are being evaluated as candidates for horizontal drilling and enhanced oil recovery from existing vertical wells based upon geological characterization and reservoir modeling case studies. Geological characterization on a local scale is focused on reservoir heterogeneity, quality, and lateral continuity, as well as possible reservoir compartmentalization, within these fields. This study utilizes representative cores, geophysical logs, and thin sections to characterize and grade each field's potential for drilling horizontal laterals from existing development wells. The results of these studies can be applied to similar fields elsewhere in the Paradox Basin and the Rocky Mountain region, the Michigan and Illinois Basins, and the Midcontinent region. This report covers research activities for the first half of the fourth project year (April 6 through October 5, 2003). The work included (1) analysis of well-test data and oil production from Cherokee and Bug fields, San Juan County, Utah, and (2) diagenetic evaluation of stable isotopes from the upper Ismay and lower Desert Creek zones of the Paradox Formation in the Blanding sub-basin, Utah. Production ''sweet spots'' and potential horizontal drilling candidates were identified for Cherokee and Bug fields. In Cherokee field, the most productive wells are located in the

  2. All-optical reservoir computing.

    Duport, François; Schneider, Bendix; Smerieri, Anteo; Haelterman, Marc; Massar, Serge

    2012-09-24

    Reservoir Computing is a novel computing paradigm that uses a nonlinear recurrent dynamical system to carry out information processing. Recent electronic and optoelectronic Reservoir Computers based on an architecture with a single nonlinear node and a delay loop have shown performance on standardized tasks comparable to state-of-the-art digital implementations. Here we report an all-optical implementation of a Reservoir Computer, made of off-the-shelf components for optical telecommunications. It uses the saturation of a semiconductor optical amplifier as nonlinearity. The present work shows that, within the Reservoir Computing paradigm, all-optical computing with state-of-the-art performance is possible.

  3. Wettability Alteration of Sandstone and Carbonate Rocks by Using ZnO Nanoparticles in Heavy Oil Reservoirs

    Masoumeh Tajmiri

    2015-10-01

    Full Text Available Efforts to enhance oil recovery through wettability alteration by nanoparticles have been attracted in recent years. However, many basic questions have been ambiguous up until now. Nanoparticles penetrate into pore volume of porous media, stick on the core surface, and by creating homogeneous water-wet area, cause to alter wettability. This work introduces the new concept of adding ZnO nanoparticles by an experimental work on wettability alteration and oil recovery through spontaneous imbibition mechanism. Laboratory tests were conducted in two experimental steps on four cylindrical core samples (three sandstones and one carbonate taken from a real Iranian heavy oil reservoir in Amott cell. In the first step, the core samples were saturated by crude oil. Next, the core samples were flooded with nanoparticles and saturated by crude oil for about two weeks. Then, the core samples were immersed in distilled water and the amount of recovery was monitored during 30 days for both steps. The experimental results showed that oil recovery for three sandstone cores changed from 20.74, 4.3, and 3.5% of original oil in place (OOIP in the absence of nanoparticles to 36.2, 17.57, and 20.68% of OOIP when nanoparticles were added respectively. Moreover, for the carbonate core, the recovery changed from zero to 8.89% of OOIP by adding nanoparticles. By the investigation of relative permeability curves, it was found that by adding ZnO nanoparticles, the crossover-point of curves shifted to the right for both sandstone and carbonate cores, which meant wettability was altered to water- wet. This study, for the first time, illustrated the remarkable role of ZnO nanoparticles in wettability alteration toward more water-wet for both sandstone and carbonate cores and enhancing oil recovery.

  4. Simulation study to determine the feasibility of injecting hydrogen sulfide, carbon dioxide and nitrogen gas injection to improve gas and oil recovery oil-rim reservoir

    Eid, Mohamed El Gohary

    This study is combining two important and complicated processes; Enhanced Oil Recovery, EOR, from the oil rim and Enhanced Gas Recovery, EGR from the gas cap using nonhydrocarbon injection gases. EOR is proven technology that is continuously evolving to meet increased demand and oil production and desire to augment oil reserves. On the other hand, the rapid growth of the industrial and urban development has generated an unprecedented power demand, particularly during summer months. The required gas supplies to meet this demand are being stretched. To free up gas supply, alternative injectants to hydrocarbon gas are being reviewed to support reservoir pressure and maximize oil and gas recovery in oil rim reservoirs. In this study, a multi layered heterogeneous gas reservoir with an oil rim was selected to identify the most optimized development plan for maximum oil and gas recovery. The integrated reservoir characterization model and the pertinent transformed reservoir simulation history matched model were quality assured and quality checked. The development scheme is identified, in which the pattern and completion of the wells are optimized to best adapt to the heterogeneity of the reservoir. Lateral and maximum block contact holes will be investigated. The non-hydrocarbon gases considered for this study are hydrogen sulphide, carbon dioxide and nitrogen, utilized to investigate miscible and immiscible EOR processes. In November 2010, re-vaporization study, was completed successfully, the first in the UAE, with an ultimate objective is to examine the gas and condensate production in gas reservoir using non hydrocarbon gases. Field development options and proces schemes as well as reservoir management and long term business plans including phases of implementation will be identified and assured. The development option that maximizes the ultimate recovery factor will be evaluated and selected. The study achieved satisfactory results in integrating gas and oil

  5. Quantitative measurement of carbon isotopic composition in CO2 gas reservoir by Micro-Laser Raman spectroscopy.

    Li, Jiajia; Li, Rongxi; Zhao, Bangsheng; Guo, Hui; Zhang, Shuan; Cheng, Jinghua; Wu, Xiaoli

    2018-04-15

    The use of Micro-Laser Raman spectroscopy technology for quantitatively determining gas carbon isotope composition is presented. In this study, 12 CO 2 and 13 CO 2 were mixed with N 2 at various molar fraction ratios to obtain Raman quantification factors (F 12CO2 and F 13CO2 ), which provide a theoretical basis for calculating the δ 13 C value. And the corresponding values were 0.523 (0Raman peak area can be used for the determination of δ 13 C values within the relative errors range of 0.076% to 1.154% in 13 CO 2 / 12 CO 2 binary mixtures when F 12CO2 /F 13CO2 is 0.466972625. In addition, measurement of δ 13 C values by Micro-Laser Raman analysis were carried out on natural CO 2 gas from Shengli Oil-field at room temperature under different pressures. The δ 13 C values obtained by Micro-Laser Raman spectroscopy technology and Isotope Ratio Mass Spectrometry (IRMS) technology are in good agreement with each other, and the relative errors range of δ 13 C values is 1.232%-6.964%. This research provides a fundamental analysis tool for determining gas carbon isotope composition (δ 13 C values) quantitatively by using Micro-Laser Raman spectroscopy. Experiment of results demonstrates that this method has the potential for obtaining δ 13 C values in natural CO 2 gas reservoirs. Copyright © 2018. Published by Elsevier B.V.

  6. Quantitative measurement of carbon isotopic composition in CO2 gas reservoir by Micro-Laser Raman spectroscopy

    Li, Jiajia; Li, Rongxi; Zhao, Bangsheng; Guo, Hui; Zhang, Shuan; Cheng, Jinghua; Wu, Xiaoli

    2018-04-01

    The use of Micro-Laser Raman spectroscopy technology for quantitatively determining gas carbon isotope composition is presented. In this study, 12CO2 and 13CO2 were mixed with N2 at various molar fraction ratios to obtain Raman quantification factors (F12CO2 and F13CO2), which provide a theoretical basis for calculating the δ13C value. And the corresponding values were 0.523 (0 Laser Raman analysis were carried out on natural CO2 gas from Shengli Oil-field at room temperature under different pressures. The δ13C values obtained by Micro-Laser Raman spectroscopy technology and Isotope Ratio Mass Spectrometry (IRMS) technology are in good agreement with each other, and the relative errors range of δ13C values is 1.232%-6.964%. This research provides a fundamental analysis tool for determining gas carbon isotope composition (δ13C values) quantitatively by using Micro-Laser Raman spectroscopy. Experiment of results demonstrates that this method has the potential for obtaining δ13C values in natural CO2 gas reservoirs.

  7. Enhanced heavy oil recovery for carbonate reservoirs integrating cross-well seismic–a synthetic Wafra case study

    Katterbauer, Klemens; Arango, Santiago; Sun, Shuyu; Hoteit, Ibrahim

    2015-01-01

    reservoir history matching framework using ensemble based techniques incorporating seismic data for enhancing reservoir characterization and improving history matches. Examining the performance on a synthetic field study of the Wafra field, we could

  8. Axial-obliquity control on the greenhouse carbon budget through mid- to high-latitude reservoirs

    Laurin, Jiří; Meyers, S. R.; Uličný, David; Jarvis, I.; Sageman, B. B.

    2015-01-01

    Roč. 30, č. 2 (2015), s. 133-149 ISSN 0883-8305 R&D Projects: GA MŠk LH12041; GA ČR GAP210/10/1991 Institutional support: RVO:67985530 Keywords : Cretaceous * carbon cycle * Milankovitch forcing Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.433, year: 2015

  9. ADVANCED CHARACTERIZATION OF FRACTURED RESERVOIRS IN CARBONATE ROCKS: THE MICHIGAN BASIN

    James R. Wood; William B. Harrison

    2002-12-01

    The purpose of the study was to collect and analyze existing data on the Michigan Basin for fracture patterns on scales ranging form thin section to basin. The data acquisition phase has been successfully concluded with the compilation of several large digital databases containing nearly all the existing information on formation tops, lithology and hydrocarbon production over the entire Michigan Basin. These databases represent the cumulative result of over 80 years of drilling and exploration. Plotting and examination of these data show that contrary to most depictions, the Michigan Basin is in fact extensively faulted and fractured, particularly in the central portion of the basin. This is in contrast to most of the existing work on the Michigan Basin, which tends to show relatively simple structure with few or minor faults. It also appears that these fractures and faults control the Paleozoic sediment deposition, the subsequent hydrocarbon traps and very likely the regional dolomitization patterns. Recent work has revealed that a detailed fracture pattern exists in the interior of the Central Michigan Basin, which is related to the mid-continent gravity high. The inference is that early Precambrian, ({approx}1 Ga) rifting events presumed by many to account for the gravity anomaly subsequently controlled Paleozoic sedimentation and later hydrocarbon accumulation. There is a systematic relationship between the faults and a number of gas and oil reservoirs: major hydrocarbon accumulations consistently occur in small anticlines on the upthrown side of the faults. The main tools used in this study to map the fault/fracture patterns are detailed, close-interval (CI = 10 feet) contouring of the formation top picks accompanied by a new way of visualizing the data using a special color spectrum to bring out the third dimension. In addition, recent improvements in visualization and contouring software were instrumental in the study. Dolomitization is common in the

  10. Sorting and degradation of permafrost-derived organic carbon during across-shelf transport in the Laptev and East Siberian shelves

    Tesi, Tommaso; Semiletov, Igor; Dudarev, Oleg; Andersson, August; Gustafsson, Örjan

    2015-04-01

    The flux of permafrost-derived organic carbon to the vast Siberian marginal seas has been receiving growing attention because its magnitude is expected to considerably increase due to changes in both river discharge and coastal permafrost stability. To what extent this relocated terrigenous organic carbon (TerrOC) pool will affect climate and biogeochemistry is currently unknown but it will largely depend on its reactivity in the marine environment. This study seeks an improved mechanistic understanding of TerrOC cycling during across-shelf transport in the vast East Siberian Arctic Seas (ESAS). Surface sediments were collected in both river-dominated and coastal erosion-dominated regions as well as at increasing distances from the shore. The organic composition in different density, size and settling velocity fractions was characterized using bulk parameters (δ13C and Δ14C) and terrigenous biomarkers including CuO-derived reaction products (lignin phenols and cutin acids) and solvent extractable HMW lipids (n-alkanoic acids, n-alkanols and n-alkanes). Key insights were gained by understanding how different TerrOC pools, operationally defined at bulk and molecular level, are distributed among different density, size and settling velocity fractions and how they change over the margin in relative concentration and composition. Our results show that the partitioning and mobility of TerrOC pools is intimately linked to density and size of particles. A large fraction of TerrOC entering the margin is associated with large, lignin-rich plant fragments which are hydrodynamically retained in coastal sediments. The across-shelf transport of TerrOC occurs primarily in the form of mineral-bound OC through the preferential mobilization of fine lithogenic particles rich in HMW lipids. Despite the mineral-association, noticeable decrease of TerrOC was observed at molecular and bulk level which indicates extensive degradation during transport across the margin. Altogether our

  11. Geothermal prospection in the Greater Geneva Basin (Switzerland and France). Impact of diagenesis on reservoir properties of the Upper Jurassic carbonate sediments

    Makhloufi, Yasin; Rusillon, Elme; Brentini, Maud; Clerc, Nicolas; Meyer, Michel; Samankassou, Elias

    2017-04-01

    Diagenesis of carbonate rocks is known to affect the petrophysical properties (porosity, permeability) of the host rock. Assessing the diagenetic history of the rock is thus essential when evaluating any reservoir exploitation project. The Canton of Geneva (Switzerland) is currently exploring the opportunities for geothermal energy exploitation in the Great Geneva Basin (GGB) sub-surface. In this context, a structural analysis of the basin (Clerc et al., 2016) associated with reservoir appraisal (Brentini et al., 2017) and rock-typing of reservoir bodies of potential interest were conducted (Rusillon et al., 2017). Other geothermal exploitation projects elsewhere (e.g. Bavaria, south Germany, Paris Basin, France) showed that dolomitized carbonate rocks have good reservoir properties and are suitable for geothermal energy production. The objectives of this work are to (1) describe and characterize the dolomitized bodies in the GGB and especially their diagenetic history and (2) quantify the reservoir properties of those bodies (porosity, permeability). Currently, our study focuses on the Upper Jurassic sedimentary bodies of the GGB. Field and well data show that the dolomitization is not ubiquitous in the GGB. Results from the petrographical analyses of the Kimmeridgian cores (Humilly-2) and of field analogues (Jura, Saleve and Vuache mountains) display complex diagenetic histories, dependent of the study sites. The paragenesis exhibits several stages of interparticular calcite cementation as well as different stages of dolomitization and/or dedolomitization. Those processes seem to follow constrained path of fluid migrations through burial, faulting or exhumation during the basin's history. These complex diagenetic histories affected the petrophysical and microstructural properties via porogenesis (conservation of initial porosity, moldic porosity) and/or poronecrosis events. The best reservoir properties appear to be recorded in patch reef and peri

  12. Maximizing Storage Rate and Capacity and Insuring the Environmental Integrity of Carbon Dioxide Sequestration in Geological Reservoirs

    L.A. Davis; A.L. Graham; H.W. Parker; J.R. Abbott; M.S. Ingber; A.A. Mammoli; L.A. Mondy; Quanxin Guo; Ahmed Abou-Sayed

    2005-12-07

    Maximizing Storage Rate and Capacity and Insuring the Environmental Integrity of Carbon Dioxide Sequestration in Geological Formations The U.S. and other countries may enter into an agreement that will require a significant reduction in CO2 emissions in the medium to long term. In order to achieve such goals without drastic reductions in fossil fuel usage, CO2 must be removed from the atmosphere and be stored in acceptable reservoirs. The research outlined in this proposal deals with developing a methodology to determine the suitability of a particular geologic formation for the long-term storage of CO2 and technologies for the economical transfer and storage of CO2 in these formations. A novel well-logging technique using nuclear-magnetic resonance (NMR) will be developed to characterize the geologic formation including the integrity and quality of the reservoir seal (cap rock). Well-logging using NMR does not require coring, and hence, can be performed much more quickly and efficiently. The key element in the economical transfer and storage of the CO2 is hydraulic fracturing the formation to achieve greater lateral spreads and higher throughputs of CO2. Transport, compression, and drilling represent the main costs in CO2 sequestration. The combination of well-logging and hydraulic fracturing has the potential of minimizing these costs. It is possible through hydraulic fracturing to reduce the number of injection wells by an order of magnitude. Many issues will be addressed as part of the proposed research to maximize the storage rate and capacity and insure the environmental integrity of CO2 sequestration in geological formations. First, correlations between formation properties and NMR relaxation times will be firmly established. A detailed experimental program will be conducted to determine these correlations. Second, improved hydraulic fracturing models will be developed which are suitable for CO2 sequestration as opposed to enhanced oil recovery (EOR

  13. Carbon dioxide emissions from the flat bottom and shallow Nam Theun 2 Reservoir: drawdown area as a neglected pathway to the atmosphere

    Deshmukh, Chandrashekhar; Guérin, Frédéric; Vongkhamsao, Axay; Pighini, Sylvie; Oudone, Phetdala; Sopraseuth, Saysoulinthone; Godon, Arnaud; Rode, Wanidaporn; Guédant, Pierre; Oliva, Priscia; Audry, Stéphane; Zouiten, Cyril; Galy-Lacaux, Corinne; Robain, Henri; Ribolzi, Olivier; Kansal, Arun; Chanudet, Vincent; Descloux, Stéphane; Serça, Dominique

    2018-03-01

    Freshwater reservoirs are a significant source of CO2 to the atmosphere. CO2 is known to be emitted at the reservoir surface by diffusion at the air-water interface and downstream of dams or powerhouses by degassing and along the river course. In this study, we quantified total CO2 emissions from the Nam Theun 2 Reservoir (Lao PDR) in the Mekong River watershed. The study started in May 2009, less than a year after flooding and just a few months after the maximum level was first reached and lasted until the end of 2013. We tested the hypothesis that soils from the drawdown area would be a significant contributor to the total CO2 emissions.Total inorganic carbon, dissolved and particulate organic carbon and CO2 concentrations were measured in 4 pristine rivers of the Nam Theun watershed, at 9 stations in the reservoir (vertical profiles) and at 16 stations downstream of the monomictic reservoir on a weekly to monthly basis. CO2 bubbling was estimated during five field campaigns between 2009 and 2011 and on a weekly monitoring, covering water depths ranging from 0.4 to 16 m and various types of flooded ecosystems in 2012 and 2013. Three field campaigns in 2010, 2011 and 2013 were dedicated to the soils description in 21 plots and the quantification of soil CO2 emissions from the drawdown area. On this basis, we calculated total CO2 emissions from the reservoir and carbon inputs from the tributaries. We confirm the importance of the flooded stock of organic matter as a source of carbon (C) fuelling emissions. We show that the drawdown area contributes, depending on the year, from 40 to 75 % of total annual gross emissions in this flat and shallow reservoir. Since the CO2 emissions from the drawdown zone are almost constant throughout the years, the large interannual variations result from the significant decrease in diffusive fluxes and downstream emissions between 2010 and 2013. This overlooked pathway in terms of gross emissions would require an in-depth evaluation

  14. Carbon dioxide emissions from the flat bottom and shallow Nam Theun 2 Reservoir: drawdown area as a neglected pathway to the atmosphere

    C. Deshmukh

    2018-03-01

    Full Text Available Freshwater reservoirs are a significant source of CO2 to the atmosphere. CO2 is known to be emitted at the reservoir surface by diffusion at the air–water interface and downstream of dams or powerhouses by degassing and along the river course. In this study, we quantified total CO2 emissions from the Nam Theun 2 Reservoir (Lao PDR in the Mekong River watershed. The study started in May 2009, less than a year after flooding and just a few months after the maximum level was first reached and lasted until the end of 2013. We tested the hypothesis that soils from the drawdown area would be a significant contributor to the total CO2 emissions.Total inorganic carbon, dissolved and particulate organic carbon and CO2 concentrations were measured in 4 pristine rivers of the Nam Theun watershed, at 9 stations in the reservoir (vertical profiles and at 16 stations downstream of the monomictic reservoir on a weekly to monthly basis. CO2 bubbling was estimated during five field campaigns between 2009 and 2011 and on a weekly monitoring, covering water depths ranging from 0.4 to 16 m and various types of flooded ecosystems in 2012 and 2013. Three field campaigns in 2010, 2011 and 2013 were dedicated to the soils description in 21 plots and the quantification of soil CO2 emissions from the drawdown area. On this basis, we calculated total CO2 emissions from the reservoir and carbon inputs from the tributaries. We confirm the importance of the flooded stock of organic matter as a source of carbon (C fuelling emissions. We show that the drawdown area contributes, depending on the year, from 40 to 75 % of total annual gross emissions in this flat and shallow reservoir. Since the CO2 emissions from the drawdown zone are almost constant throughout the years, the large interannual variations result from the significant decrease in diffusive fluxes and downstream emissions between 2010 and 2013. This overlooked pathway in terms of gross emissions would require

  15. An Efficient Upscaling Process Based on a Unified Fine-scale Multi-Physics Model for Flow Simulation in Naturally Fracture Carbonate Karst Reservoirs

    Bi, Linfeng

    2009-01-01

    The main challenges in modeling fluid flow through naturally-fractured carbonate karst reservoirs are how to address various flow physics in complex geological architectures due to the presence of vugs and caves which are connected via fracture networks at multiple scales. In this paper, we present a unified multi-physics model that adapts to the complex flow regime through naturally-fractured carbonate karst reservoirs. This approach generalizes Stokes-Brinkman model (Popov et al. 2007). The fracture networks provide the essential connection between the caves in carbonate karst reservoirs. It is thus very important to resolve the flow in fracture network and the interaction between fractures and caves to better understand the complex flow behavior. The idea is to use Stokes-Brinkman model to represent flow through rock matrix, void caves as well as intermediate flows in very high permeability regions and to use an idea similar to discrete fracture network model to represent flow in fracture network. Consequently, various numerical solution strategies can be efficiently applied to greatly improve the computational efficiency in flow simulations. We have applied this unified multi-physics model as a fine-scale flow solver in scale-up computations. Both local and global scale-up are considered. It is found that global scale-up has much more accurate than local scale-up. Global scale-up requires the solution of global flow problems on fine grid, which generally is computationally expensive. The proposed model has the ability to deal with large number of fractures and caves, which facilitate the application of Stokes-Brinkman model in global scale-up computation. The proposed model flexibly adapts to the different flow physics in naturally-fractured carbonate karst reservoirs in a simple and effective way. It certainly extends modeling and predicting capability in efficient development of this important type of reservoir.

  16. Origins of carbonate spherulites: Implications for Brazilian Aptian pre-salt reservoir

    Chafetz, Henry; Barth, Jennifer; Cook, Megan; Guo, Xuan; Zhou, Jie

    2018-03-01

    Spherulites, spherical to elliptical allochems composed of crystals radiating from a common core, investigated from a variety of depositional settings, e.g., hot springs, ambient water temperature geyser, tufa, and caliche, are all composed of a fine-grained nucleus made-up of carbonate encrusted bacterial bodies, biofilms, and/or EPS and surrounded by a cortex of radiating crystals of either aragonite or calcite. The microbes and their by-products in the nucleus induced the precipitation of carbonate, overcoming the inhibition to initiate crystal formation. The enveloping radiating crystals comprising aragonitic cortices tended to grow abiotically producing well-formed euhedral crystals with a paucity of included bacterial fossils. Whereas those cortical crystals made-up of calcite commonly contained bacterial fossils, indicating that the bacterial colonies contributed to the calcitic cortical crystal precipitation. Similar spherulites form a thick, widespread accumulation in the Aptian Pre-Salt lacustrine deposits in the Campos Basin, offshore Brazil. As with the travertine, tufa, and caliche spherulites, the Pre-Salt spherulites most likely initiated carbonate precipitation around bacterial colonies and/or their bioproducts, probably while afloat in a lacustrine water column before settling to the water-sediment interface. Absence of inter-spherulite sediment and the spherulite-to-spherulite compaction indicate that cortical crystal growth continued while the spherulites were at the sediment-water interface rather than displacively within a sediment.

  17. Conversion of 3D seismic attributes to reservoir hydraulic flow units using a neural network approach: An example from the Kangan and Dalan carbonate reservoirs, the world's largest non-associated gas reservoirs, near the Persian Gulf

    Mohammad Amin Dezfoolian

    2013-07-01

    Full Text Available This study presents an intelligent model based on probabilistic neural networks (PNN to produce a quantitative formulation between seismic attributes and hydraulic flow units (HFUs. Neural networks have been used for the last several years to estimate reservoir properties. However, their application for hydraulic flow unit estimation on a cube of seismic data is an interesting topic for research. The methodology for this application is illustrated using 3D seismic attributes and petrophysical and core data from 6 wells from the Kangan and Dalan gas reservoirs in the Persian Gulf basin. The methodology introduced in this study estimates HFUs from a large volume of 3D seismic data. This may increase exploration success rates and reduce costs through the application of more reliable output results in hydrocarbon exploration programs. 4 seismic attributes, including acoustic impedance, dominant fre- quency, amplitude weighted phase and instantaneous phase, are considered as the optimal inputs for pre- dicting HFUs from seismic data. The proposed technique is successfully tested in a carbonate sequence of Permian-Triassic rocks from the studied area. The results of this study demonstrate that there is a good agreement between the core and PNN-derived flow units. The PNN used in this study is successful in modeling flow units from 3D seismic data for which no core data or well log data are available.  Resumen Este estudio presenta un modelo inteligente basado en redes neuronales probabilísticas (PNN para pro- ducir una formulación cuantitativa entre atributos sísmicos y unidades de flujo hidráulico (HFU. Las redes neuronales han sido utilizadas durante los últimos años para estimar las propiedades de reserva. Sin embargo, su aplicación para estimación de unidades de flujo hidráulico en un cubo de datos sísmicos es un tema importante de investigación. La metodología para esta aplicación está ilustrada a partir de datos tridimensionales y

  18. Dolomitization of carbonated reservoirs of platforms. From geologic data to modeling. Example of the great Bahama bank; La dolomitisation des reservoirs carbonates de plate-forme. Des donnees geologiques a la modelisation. Exemple du Grand Banc des Bahamas

    Caspard, E.

    2002-09-01

    Dolomitization has long been one of the most studied geological processes because of its economic interest (dolomitic rocks form a significant share of hydrocarbon reservoirs) as well as its academic interest, based on the fact that dolomite scarcely forms in current and recent marine environments whereas seawater is highly over-saturated; and that it is still not possible to synthesize it in laboratory under the same conditions. We used data collected by the University of Miami (Bahamas Drilling Project, ODP Leg 166) to understand the geological context of complete dolomitization of a Messinian 60 m thick reef unit. Classical methods of petrographic analysis of thin sections (optical microscopy, cathodoluminescence, scanning electron microscopy, in situ isotopic analyze using ionic microprobe) showed that the intensity of dolomitization is not controlled by the initial texture of the sediment, that the key parameter for dolomitization is the conservation of the initial mineralogy of magnesian bio-clasts, and that redox conditions, salinity and/or temperature of the precipitation fluid varied significantly during the process. Hydrodynamic modelling showed that during periods of high sea-level, Kohout thermal convection is a viable mechanism for driving marine fluids through the sediments. The key parameter for fluid circulations is the permeability anisotropy on the platform scale. Geochemical modelling showed that seawater is able to induce a complete dolomitization over durations of around one million years. Sensitivity tests showed that the critical parameter (as well as one of the less well-known) to describe diagenetic processes in carbonates is the water/rock reactions kinetics and in particular the precipitation kinetics of carbonate minerals. We finally propose that the dolomitization of the reef unit of the Unda well took place during the high sea-level period which extended over 1,1 My in the early Pliocene, according to the Kohout thermal convection

  19. A Review of Recovery Mechanisms of Ionically Modified Waterflood in Carbonate Reservoirs

    Sohal, Muhammad Adeel Nassar; Thyne, Geoffrey; Søgaard, Erik Gydesen

    2016-01-01

    . This process has been evaluated as a wettability-modifying agent in carbonates and captured the global research focus in water-based enhanced oil recovery (EOR) methods. This paper provides a comprehensive review of the published research to speed the process of further investigations in this field. The review......Advanced water flooding is a process in which the ionic strength as well as the ionic composition of the injected water is tuned to improve the oil recovery. It has been observed in field trials and in lab core flooding experiments; advanced water flooding has the potential to recover additional oil...

  20. Carbon sequestration potential of the Habanero reservoir when carbon dioxide is used as the heat exchange fluid

    Chaoshui Xu

    2016-02-01

    Full Text Available The use of sequestered carbon dioxide (CO2 as the heat exchange fluid in enhanced geothermal system (EGS has significant potential to increase their productivity, contribute further to reducing carbon emissions and increase the economic viability of geothermal power generation. Coupled CO2 sequestration and geothermal energy production from hot dry rock (HDR EGS were first proposed 15 years ago but have yet to be practically implemented. This paper reviews some of the issues in assessing these systems with particular focus on the power generation and CO2 sequestration capacity. The Habanero geothermal field in the Cooper Basin of South Australia is assessed for its potential CO2 storage capacity if supercritical CO2 is used as the working fluid for heat extraction. The analysis suggests that the major CO2 sequestration mechanisms are the storage in the fracture-stimulation damaged zone followed by diffusion into the pores within the rock matrix. The assessment indicates that 5% of working fluid loss commonly suggested as the storage capacity might be an over-estimate of the long-term CO2 sequestration capacity of EGS in which supercritical CO2 is used as the circulation fluid.

  1. Prediction of total organic carbon content in shale reservoir based on a new integrated hybrid neural network and conventional well logging curves

    Zhu, Linqi; Zhang, Chong; Zhang, Chaomo; Wei, Yang; Zhou, Xueqing; Cheng, Yuan; Huang, Yuyang; Zhang, Le

    2018-06-01

    There is increasing interest in shale gas reservoirs due to their abundant reserves. As a key evaluation criterion, the total organic carbon content (TOC) of the reservoirs can reflect its hydrocarbon generation potential. The existing TOC calculation model is not very accurate and there is still the possibility for improvement. In this paper, an integrated hybrid neural network (IHNN) model is proposed for predicting the TOC. This is based on the fact that the TOC information on the low TOC reservoir, where the TOC is easy to evaluate, comes from a prediction problem, which is the inherent problem of the existing algorithm. By comparing the prediction models established in 132 rock samples in the shale gas reservoir within the Jiaoshiba area, it can be seen that the accuracy of the proposed IHNN model is much higher than that of the other prediction models. The mean square error of the samples, which were not joined to the established models, was reduced from 0.586 to 0.442. The results show that TOC prediction is easier after logging prediction has been improved. Furthermore, this paper puts forward the next research direction of the prediction model. The IHNN algorithm can help evaluate the TOC of a shale gas reservoir.

  2. Pore facies analysis: incorporation of rock properties into pore geometry based classes in a Permo-Triassic carbonate reservoir in the Persian Gulf

    Rahimpour-Bonab, H; Aliakbardoust, E

    2014-01-01

    Pore facies analysis is a useful method for the classification of reservoir rocks according to pore geometry characteristics. The importance of this method is related to the dependence of the dynamic behaviour of the reservoir rock on the pore geometry. In this study, pore facies analysis was performed by the quantification and classification of the mercury injection capillary pressure (MICP) curves applying the multi-resolution graph-based clustering (MRGC) method. Each pore facies includes a limited variety of rock samples with different depositional fabrics and diagenetic histories, which are representative of one type of pore geometry. The present pore geometry is the result of the interaction between the primary rock fabric and its diagenetic overprint. Thus the variations in petrographic properties can be correlated with the pore geometry characteristics. Accordingly, the controlling parameters in the pore geometry characteristics were revealed by detailed petrographic analysis in each pore facies. The reservoir rock samples were then classified using the determined petrographic properties which control the pore system quality. This method is proposed for the classification of reservoir rocks in complicated carbonate reservoirs, in order to reduce the incompatibility of traditional facies analysis with pore system characteristics. The method is applicable where enough capillary pressure data is not available. (papers)

  3. Discovery of reservoirs in carbonate deposits of the Perm Province using tracer materials

    Dakhnov, V.N.; Bykov, V.N.; Naborshchikova, I.I.; Zvyagin, G.A.

    1978-01-01

    The methods are described to define the oil-bearing collectors of the carbonate deposits of the Perm region by using labelled substances. The suspension containing tetra-boronatrium-borax was forced into productive layers. The penetration of the borax solution into pervious collectors was evidenced by sharply decreased estimates obtained by neutron logging technique. The minimum borax concentration sufficient for defining collectors by the neutron gamma method constitutes 1-2 g/l. With increasing the borax concentration to 50 g/l the radius of neutron method investigations amounts to 60 cm. The technique was used to determine the effective thickness of the Gezhsky productive layer, which was found to be 20% larger than that earlier determined by the standard geophysical borehole investigations. The data were confirmed by the layer sampling results

  4. Western Sicily (Italy), a key area for understanding geothermal system within carbonate reservoirs

    Montanari, D.; Bertini, G.; Botteghi, S.; Catalano, R.; Contino, A.; Doveri, M.; Gennaro, C.; Gianelli, G.; Gola, G.; Manzella, A.; Minissale, A.; Montegrossi, G.; Monteleone, S.; Trumpy, E.

    2012-12-01

    Oil exploration in western Sicily started in the late 1950s when several exploration wells were drilled, and continued with the acquisition of many seismic reflection profiles and the drilling of new wells in the1980s. The geological interpretation of these data mainly provided new insights for the definition of geometric relationships between tectonic units and structural reconstruction at depth. Although it has not produced completely satisfactory results for oil industry, this hydrocarbon exploration provided a great amount of data, resulting very suitable for geothermal resource assessment. From a geothermal point of view western Sicily is, indeed, a very promising area, with the manifestation at surface of several thermal springs, localized areas of high heat flux and thick carbonates units uninterruptedly developing from surface up top great depths. These available data were often collected with the modalities and purposes typical of oil exploration, not always the finest for geothermal exploration as in the case of temperature measurements. The multidisciplinary and integrated review of these data, specifically corrected for geothermal purposes, and the integration with new data acquired in particular key areas such as the Mazara Del Vallo site in the southern part of western Sicily, allowed us to better understand this medium-enthalpy geothermal system, to reconstruct the modalities and peculiarities of fluids circulation, and to evaluate the geothermal potentialities of western Sicily. We suggest that western Sicily can be taken as a reference for the understanding of geothermal systems developed at a regional scale within carbonate rocks. This study was performed within the framework of the VIGOR project (http://www.vigor-geotermia.it).

  5. The Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) FTS: Results From the 2012/13 Alaska Campaigns

    kurosu, T. P.; Miller, C. E.; Dinardo, S.

    2013-12-01

    The Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) is an aircraft-based Earth Venture 1 mission to study the carbon balance of the Alaskan Arctic ecosystem, with a particular focus on carbon release from melting permafrost. Operating from its base in Fairbanks, AK, the CARVE aircraft covers a range of principle flight paths in the Alaskan interior, the Yukon River valley, and northern Alaska coast around Barrow and Dead Horse. Flight paths are chosen to maximize ecosystem variability and and cover burn-recovery/regrowth sequences. CARVE observations cover the Arctic Spring/Summer/Fall seasons, with multiple flights per season and principle flight paths. Science operations started in 05/2012 and are currently envisaged to continue until 2015. The CARVE suite of instruments includes flask measurements and in situ gas analyzers for CO2, CH4 and CO observations, an active/passive L-band radar for surface conditions (freeze/thaw state), and a three-band polarizing Fourier Transform Spectrometer (FTS) for column measurements of CO2, CH4, CO, and interfering species (e.g., H2O). The FTS covers the spectral regions of 4,200-4,900 cm-1 (CH4, CO), 5,800-6,400 cm-1 (CO2), and 12,900-13,200 cm-1 (O2), with a spectral resolution of 0.2 cm-1. Aircraft-based FTS science observations in Alaska have been performed since 23-05-2012. First-version data products from all CARVE instruments derived from observations during the 2012 campaign were publicly released earlier in 2013. The FTS has performed well during flight conditions, particularly with respect to vibration damping. Outstanding challenges include the need for improved spectral and radiometric calibration, as well as compensating for low signal-to-noise spectra acquired under Alaskan flight conditions. We present results from FTS column observations of CO2, CH4, and CO, observed during the 2012 and 2013 campaigns, including preliminary comparisons of CARVE FTS measurements with satellite observations of CO2

  6. Evaluation of Commercial Off-the-Shelf Sorbents and Catalysts for Control of Ammonia and Carbon Monoxide

    Luna, Bernadette; Somi, George; Winchester, J. Parker; Grose, Jeffrey; Mulloth, Lila; Perry, Jay L.

    2013-01-01

    Designers of future space vehicles envision simplifying the Atmosphere Revitalization (AR) system by combining the functions of trace contaminant (TC) control and carbon dioxide removal into one swing-bed system. Flow rates and bed sizes of the TC and CO2 systems have historically been very different. There is uncertainty about the ability of trace contaminant sorbents to adsorb adequately in high-flow or short bed length configurations, and to desorb adequately during short vacuum exposures. There is also concern about ambient ammonia levels in the absence of a condensing heat exchanger. In addition, new materials and formulations have become commercially available, formulations never evaluated by NASA for purposes of trace contaminant control. The optimal air revitalization system for future missions may incorporate a swing-bed system for carbon dioxide (CO2) and partial trace contaminant control, with a reduced-size, low-power, targeted trace contaminant system supplying the remaining contaminant removal capability. This paper describes the results of a comparative experimental investigation into materials for trace contaminant control that might be part of such a system. Ammonia sorbents and low temperature carbon monoxide (CO) oxidation catalysts are the foci. The data will be useful to designers of AR systems for future flexible path missions. This is a continuation of work presented in a prior year, with extended test results.

  7. Toward a quantitative and empirical dissolved organic carbon budget for the Gulf of Maine, a semienclosed shelf sea

    Balch, William; Huntington, Thomas G.; Aiken, George R.; Drapeau, David; Bowler, Bruce; Lubelczyk, Laura; Butler, Kenna D.

    2016-01-01

    A time series of organic carbon export from Gulf of Maine (GoM) watersheds was compared to a time series of biological, chemical, bio-optical, and hydrographic properties, measured across the GoM between Yarmouth, NS, Canada, and Portland, ME, U.S. Optical proxies were used to quantify the dissolved organic carbon (DOC) and particulate organic carbon in the GoM. The Load Estimator regression model applied to river discharge data demonstrated that riverine DOC export (and its decadal variance) has increased over the last 80 years. Several extraordinarily wet years (2006–2010) resulted in a massive pulse of chromophoric dissolved organic matter (CDOM; proxy for DOC) into the western GoM along with unidentified optically scattering material (Time lags between DOC discharge and its appearance in the GoM increased with distance from the river mouths. Algae were also a significant source of DOC but not CDOM. Gulf-wide algal primary production has decreased. Increases in precipitation and DOC discharge to the GoM are predicted over the next century.

  8. Integrated Outcrop and Subsurface Studies of the Interwell Environment of Carbonate Reservoirs: Clear Fork (Leonaradian Age) Reservoirs, West Texas and New Mexico, Semi-Annual; SEMIANNUAL

    Ruppel, Stephen C.; Jennings, James W.; Laubach, Stephen E.

    2001-01-01

    Outcrop studies include stratigraphic and petrophysical analysis. Analysis of the detailed sequence- and cycle-scale architecture of the Clear Fork reservoir-equivalent outcrops in Apache Canyon is nearly complete. This work reveals two high-frequency transgressive-regressive sequences (HFS) in the lower Clear Fork composite depositional sequence and three HFS in the basal middle Clear Fork composite depositional sequence. A 1,800-ft transect of 1-inch-diameter samples was collected from one cycle at the Apache Canyon outcrop. The transect was sampled with 5-ft spacing, but there were some gaps due to cover and cliff, resulting in 181 samples. Permeability, porosity, and grain density were measured, and the spatial statistics are being analyzed geostatistically

  9. Understanding the fracture role on hydrocarbon accumulation and distribution using seismic data: A case study on a carbonate reservoir from Iran

    Karimpouli, Sadegh; Hassani, Hossein; Malehmir, Alireza; Nabi-Bidhendi, Majid; Khoshdel, Hossein

    2013-09-01

    The South Pars, the largest gas field in the world, is located in the Persian Gulf. Structurally, the field is part of the Qatar-South Pars arch which is a regional anticline considered as a basement-cored structure with long lasting passive folding induced by salt withdrawal. The gas-bearing reservoir belongs to Kangan and Dalan formations dominated by carbonate rocks. The fracture role is still unknown in gas accumulation and distribution in this reservoir. In this paper, the Scattering Index (SI) and the semblance methods based on scattered waves and diffraction signal studies, respectively, were used to delineate the fracture locations. To find the relation between fractures and gas distribution, desired facies containing the gas, were defined and predicted using a method based on Bayesian facies estimation. The analysis and combination of these results suggest that preference of fractures and/or fractured zones are negligible (about 1% of the total volume studied in this paper) and, therefore, it is hard to conceive that they play an important role in this reservoir. Moreover, fractures have no considerable role in gas distribution (less than 30%). It can be concluded from this study that sedimentary processes such as digenetic, primary porosities and secondary porosities are responsible for the gas accumulation and distribution in this reservoir.

  10. Anomalies of natural gas compositions and carbon isotope ratios caused by gas diffusion - A case from the Donghe Sandstone reservoir in the Hadexun Oilfield, Tarim Basin, northwest China

    Wang, Yangyang; Chen, Jianfa; Pang, Xiongqi; Zhang, Baoshou; Wang, Yifan; He, Liwen; Chen, Zeya; Zhang, Guoqiang

    2018-05-01

    Natural gases in the Carboniferous Donghe Sandstone reservoir within the Block HD4 of the Hadexun Oilfield, Tarim Basin are characterized by abnormally low total hydrocarbon gas contents ( δ13C ethane (C2) gas has never been reported previously in the Tarim Basin and such large variations in δ13C have rarely been observed in other basins globally. Based on a comprehensive analysis of gas geochemical data and the geological setting of the Carboniferous reservoirs in the Hadexun Oilfield, we reveal that the anomalies of the gas compositions and carbon isotope ratios in the Donghe Sandstone reservoir are caused by gas diffusion through the poorly-sealed caprock rather than by pathways such as gas mixing, microorganism degradation, different kerogen types or thermal maturity degrees of source rocks. The documentation of an in-reservoir gas diffusion during the post entrapment process as a major cause for gas geochemical anomalies may offer important insight into exploring natural gas resources in deeply buried sedimentary basins.

  11. Well-based stable carbon isotope leakage monitoring of an aquifer overlying the CO2 storage reservoir at the Ketzin pilot site, Germany

    Nowak, Martin; Myrttinen, Anssi; Zimmer, Martin; van Geldern, Robert; Barth, Johannes A. C.

    2014-05-01

    At the pilot site for CO2 storage in Ketzin, a new well-based leakage-monitoring concept was established, comprising geochemical and hydraulic observations of the aquifer directly above the CO2 reservoir (Wiese et al., 2013, Nowak et al. 2013). Its purpose was to allow early detection of un-trapped CO2. Within this monitoring concept, we established a stable carbon isotope monitoring of dissolved inorganic carbon (DIC). If baseline isotope values of aquifer DIC (δ13CDIC) and reservoir CO2 (δ13CCO2) are known and distinct from each other, the δ13CDIC has the potential to serve as an an early indicator for an impact of leaked CO2 on the aquifer brine. The observation well of the overlying aquifer was equipped with an U-tube sampling system that allowed sampling of unaltered brine. The high alkaline drilling mud that was used during well drilling masked δ13CDIC values at the beginning of the monitoring campaign. However, subsequent monitoring allowed observing on-going re-equilibration of the brine, indicated by changing δ13CDIC and other geochemical values, until values ranging around -23 ‰ were reached. The latter were close to baseline values before drilling. Baselineδ13CDIC and δ13CCO2 values were used to derive a geochemical and isotope model that predicts evolution of δ13CDIC, if CO2 from the reservoir would leak into the aquifer. The model shows that equilibrium isotope fractionation would have to be considered if CO2 dissolves in the brine. The model suggests that stable carbon isotope monitoring is a suitable tool to assess the impact of injected CO2 in overlying groundwater aquifers. However, more data are required to close gaps of knowledge about fractionation behaviour within the CO2(g) - DIC system under elevated pressures and temperatures. Nowak, M., Myrttinen, A., Zimmer, M., Wiese, B., van Geldern, R., Barth, J.A.C., 2013. Well-based, Geochemical Leakage Monitoring of an Aquifer Immediately Above a CO2 Storage Reservoir by Stable Carbon

  12. Multiple episodes of dolomitization and dolomite recrystallization during shallow burial in Upper Jurassic shelf carbonates: eastern Swabian Alb, southern Germany

    Reinhold, C.

    1998-10-01

    The Upper Jurassic of the eastern Swabian Alb is composed of oolitic platform sands with associated microbe-siliceous sponge mounds at the platform margins. They are surrounded by argillaceous or calcareous mudstones and marl-limestone alternations, deposited in adjacent marl basins. Partial to complete dolomitization is predominantly confined to the mound facies. Six types of dolomite, as well as one type of ankerite, document a complex diagenetic history during shallow burial with multiple episodes of dolomite formation and recrystallization. The earliest massive matrix dolomitization is Ca-rich, has slightly depleted oxygen isotope values relative to Late Jurassic seawater, and carbon isotopic values in equilibrium with Late Jurassic seawater. This initial massive matrix dolomitization occurred during latest Jurassic to earliest Cretaceous and is related to pressure dissolution during very shallow burial at temperatures of at least 50°C. Hydrologic conditions and mass-balance calculations indicate that burial compaction provided sufficient fluids for dolomitization. Mg is derived from negligibly modified seawater, that was expelled from the adjacent off-reef strata into the mound facies. Position of the mounds along the platform margins controlled the distribution of the shallow-burial dolomite. Covariant trends between textural modification, increasing stoichiometry, partial changes in trace element content (Mn, Fe, Sr) and depletion in stable isotopes as well as distinctive CL pattern illustrate two recrystallization phases of the precursor matrix dolomite during further burial at elevated temperatures. Strong Sr enrichment of the second phase of recrystallized dolomite is ascribed to Sr-rich meteoric waters descending from overlying aragonite-bearing reef limestones or evaporite-bearing peritidal carbonates. Late-stage coarsely crystalline dolomite cements occur as vug and fracture fillings and formed during burial. Ankerite, associated with sulphide and

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

    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)

  14. Play Analysis and Digital Portfolio of Major Oil Reservoirs in the Permian Basin: Application and Transfer of Advanced Geological and Engineering Technologies for Incremental Production Opportunities

    Shirley P. Dutton; Eugene M. Kim; Ronald F. Broadhead; Caroline L. Breton; William D. Raatz; Stephen C. Ruppel; Charles Kerans

    2004-01-13

    A play portfolio is being constructed for the Permian Basin in west Texas and southeast New Mexico, the largest onshore petroleum-producing basin in the United States. Approximately 1,300 reservoirs in the Permian Basin have been identified as having cumulative production greater than 1 MMbbl (1.59 x 10{sup 5} m{sup 3}) of oil through 2000. Of these significant-sized reservoirs, approximately 1,000 are in Texas and 300 in New Mexico. There are 32 geologic plays that have been defined for Permian Basin oil reservoirs, and each of the 1,300 major reservoirs was assigned to a play. The reservoirs were mapped and compiled in a Geographic Information System (GIS) by play. The final reservoir shapefile for each play contains the geographic location of each reservoir. Associated reservoir information within the linked data tables includes RRC reservoir number and district (Texas only), official field and reservoir name, year reservoir was discovered, depth to top of the reservoir, production in 2000, and cumulative production through 2000. Some tables also list subplays. Play boundaries were drawn for each play; the boundaries include areas where fields in that play occur but are smaller than 1 MMbbl (1.59 x 10{sup 5} m{sup 3}) of cumulative production. Oil production from the reservoirs in the Permian Basin having cumulative production of >1 MMbbl (1.59 x 10{sup 5} m{sup 3}) was 301.4 MMbbl (4.79 x 10{sup 7} m{sup 3}) in 2000. Cumulative Permian Basin production through 2000 was 28.9 Bbbl (4.59 x 10{sup 9} m{sup 3}). The top four plays in cumulative production are the Northwest Shelf San Andres Platform Carbonate play (3.97 Bbbl [6.31 x 10{sup 8} m{sup 3}]), the Leonard Restricted Platform Carbonate play (3.30 Bbbl [5.25 x 10{sup 8} m{sup 3}]), the Pennsylvanian and Lower Permian Horseshoe Atoll Carbonate play (2.70 Bbbl [4.29 x 10{sup 8} m{sup 3}]), and the San Andres Platform Carbonate play (2.15 Bbbl [3.42 x 10{sup 8} m{sup 3}]). Detailed studies of three reservoirs

  15. Area of Interest 1, CO2 at the Interface. Nature and Dynamics of the Reservoir/Caprock Contact and Implications for Carbon Storage Performance

    Mozley, Peter [New Mexico Institute Of Mining And Technology, Socorro, NM (United States); Evans, James [New Mexico Institute Of Mining And Technology, Socorro, NM (United States); Dewers, Thomas [New Mexico Institute Of Mining And Technology, Socorro, NM (United States)

    2014-10-31

    Formation reservoir/caprock interface in order to extend our work to a reservoir/caprock pair this is currently being assessed for long-term carbon storage. These analyses indicate that interface features similar to those observed at the Utah sites 3 were not observed. Although not directly related to our main study topic, one byproduct of our investigation is documentation of exceptionally high degrees of heterogeneity in the pore-size distribution of the Mount Simon Sandstone. This suggests that the unit has a greater-than-normal potential for residual trapping of supercritical CO2.

  16. The applicability of C-14 measurements in the soil gas for the assessment of leakage out of underground carbon dioxide reservoirs

    Chałupnik Stanisław

    2014-03-01

    Full Text Available Poland, due to the ratification of the Kioto Protocol, is obliged to diminish the emission of greenhouse gases. One of the possible solutions of this problem is CO2 sequestration (CCS - carbon capture and storage. Such an option is a priority in the European Union. On the other hand, CO2 sequestration may be potentially risky in the case of gas leakage from underground reservoirs. The most dangerous event may be a sudden release of the gas onto the surface. Therefore, it is very important to know if there is any escape of CO2 from underground gas reservoirs, created as a result of sequestration. Such information is crucial to ensure safety of the population in areas located above geological reservoirs. It is possible to assess the origin of carbon dioxide, if the measurement of radiocarbon 14C concentration in this gas is done. If CO2 contains no 14C, it means, that the origin of the gas is either geological or the gas has been produced as a result of combustion of fossil fuels, like coal. A lot of efforts are focused on the development of monitoring methods to ensure safety of CO2 sequestration in geological formations. A radiometric method has been tested for such a purpose. The main goal of the investigations was to check the application possibility of such a method. The technique is based on the liquid scintillation counting of samples. The gas sample is at first bubbled through the carbon dioxide adsorbent, afterwards the adsorbent is mixed with a dedicated cocktail and measured in a low-background liquid scintillation spectrometer Quantulus. The described method enables measurements of 14C in mine and soil gas samples.

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

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

    2018-03-20

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

  18. Sedimentary mode and reservoir genesis of dual grain banks at the Lower Cambrian Longwangmiao Fm carbonate ramp in the Sichuan Basin

    Jinhu Du

    2016-11-01

    Full Text Available The gas reservoir of the Lower Cambrian Longwangmiao Fm in the Sichuan Basin is a supergiant integral marine carbonate gas reservoir whose single scale is currently the largest in China. In order to figure out its sedimentary model and reservoir genesis, its geological structures and sedimentary settings and facies were analyzed comprehensively and the lithofacies paleographic map was plotted. It is revealed that the following sedimentary facies are successively developed in the Longwangmiao Fm from West Sichuan to Southeast Chongqing: diamictic tidal flat at the back ramp, grain bank (the upper bank at the inner/shallow ramp – interbank sea (depression, deeper open bay at the platform depression of inner ramp → evaporative lagoon → evaporative tidal flat, tempestite at the middle ramp – barrier beach – mud mound beach (the lower bank, and outer ramp – basin. Accordingly, the specific sedimentary model of dual grain banks in the Longwangmiao Fm carbonate ramp was established as follows. Firstly, in this model, dual grain banks are symmetrically developed with Wanzhou–Yibin platform depression as the axis, on whose dual sides the paleohighs have shallow water bodies with strong energy. Compared with the classical model, the new one has a new upper bank which is developed around the paleohighs covering an area of about 8 × 104 km2. Secondly, the upper bank is large for its paleogeomorphology being located at the highest position with the strongest water energy during deposition. Therefore, it is prone to dolomitization and meteoric dissolution respectively during contemporaneous–penecontemporaneous hot-dry and hot-humid periods, and especially the Caledonian–Early Hercynian denudation wedge out tends to undergo post-supergene multiphase karstification. Therefore, quality reservoirs are more developed on scale. Thirdly, the intergranular pores and vermes moldic pores were dissolved and enlarged due to the multiphase

  19. Spatio-temporal variations of carbon dioxide and its gross emission regulated by artificial operation in a typical hydropower reservoir in China.

    Li, Zhe; Zhang, Zengyu; Xiao, Yan; Guo, Jinsong; Wu, Shengjun; Liu, Jing

    2014-05-01

    Supersaturation and excess emission of greenhouse gases in freshwater reservoirs have received a great deal of attention in recent years. Although impoundment of reservoirs has been shown to contribute to the net emission of greenhouse gases, reservoir age, geographical distribution, submerged soil type and artificial regulation also have a great impact on their emissions. To examine how large scale reservoir operation impact the water column CO2 and its air-water interface flux, a field study was conducted in 2010 to evaluate potential ecological processes that regulate the partial pressure of CO2 (pCO2) in the water column in the Pengxi River backwater area (PBA), a typical tributary in the Three Gorges Reservoir, China. Measurements of total alkalinity (TA), pH and water temperature were applied to compute the pCO2. And this approach was also validated by calculation of pCO2 from the dissolved inorganic carbon data of samples. Partial least squares (PLS) regression was used to determine how the dynamics of the water pCO2 were related to the available variables. The estimated pCO2 in our sample ranged from 26 to 4,087 μatm in the surface water. During low water operation from July to early September, there was an obvious pCO2 stratification, and pCO2 in the surface was almost unsaturated. This phenomenon was also observed in the spring bloom during discharge period. Conversely, there was no significant pCO2 stratification and the entire water column was supersaturated during high water operation from November to the following February. Significant correlation was observed between the magnitude of pCO2, DO and chlorophyll a, suggesting that phytoplankton dynamics regulate pCO2 in the PBA. The average areal rate of CO2 emissions from the Pengxi River ranged from 18.06 to 48.09 mmol m(-2) day(-1), with an estimated gross CO2 emission from the water surface of 14-37 t day(-1) in this area in 2010. Photosynthesis and respiration rates by phytoplankton might be the

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

    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

  1. APPLICATION OF INTEGRATED RESERVOIR MANAGEMENT AND RESERVOIR CHARACTERIZATION

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

    2000-03-01

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

  2. Thermodynamic analysis of a compressed carbon dioxide energy storage system using two saline aquifers at different depths as storage reservoirs

    Liu, Hui; He, Qing; Borgia, Andrea; Pan, Lehua; Oldenburg, Curtis M.

    2016-01-01

    Highlights: • A compressed CO_2 energy storage system using two storage reservoirs is presented. • Compressed CO_2 energy storage density is higher than that of CAES. • The effects of storage reservoir pressure on the system performance are studied. - Abstract: Compressed air energy storage (CAES) is one of the leading large-scale energy storage technologies. However, low thermal efficiency and low energy storage density restrict its application. To improve the energy storage density, we propose a two-reservoir compressed CO_2 energy storage system. We present here thermodynamic and parametric analyses of the performance of an idealized two-reservoir CO_2 energy storage system under supercritical and transcritical conditions using a steady-state mathematical model. Results show that the transcritical compressed CO_2 energy storage system has higher round-trip efficiency and exergy efficiency, and larger energy storage density than the supercritical compressed CO_2 energy storage. However, the configuration of supercritical compressed CO_2 energy storage is simpler, and the energy storage densities of the two systems are both higher than that of CAES, which is advantageous in terms of storage volume for a given power rating.

  3. Reservoir management

    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

  4. Reservoir management

    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

  5. Flexible three-dimensional electrodes of hollow carbon bead strings as graded sulfur reservoirs and the synergistic mechanism for lithium–sulfur batteries

    Yang, Dan [College of Materials Science and Engineering, Sichuan University, Chengdu, 610064 (China); Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900 (China); Ni, Wei, E-mail: niwei@iccas.ac.cn [Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900 (China); Cheng, Jianli; Wang, Zhuanpei; Wang, Ting; Guan, Qun [Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900 (China); Zhang, Yun, E-mail: y_zhang@scu.edu.cn [College of Materials Science and Engineering, Sichuan University, Chengdu, 610064 (China); Wu, Hao [College of Materials Science and Engineering, Sichuan University, Chengdu, 610064 (China); Li, Xiaodong [Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900 (China); Wang, Bin, E-mail: edward.bwang@gmail.com [Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621900 (China)

    2017-08-15

    Graphical abstract: Flexible three-dimensional electrode comprised of stringed N-doped hollow carbon spheres shows a synergistic sulfur confinement mechanism and a higher energy/power density for the promising lithium-sulfur batteries compared with traditional electrodes. - Highlights: • Hollow carbon beads on string structure was first prepared. • Flexible 3D electrodes as graded reservoirs for polysulfides were conducted. • Synergistic effect for enhanced polysulfides storage was claimed. - Abstract: Three-dimensional (3D) flexible electrodes of stringed hollow nitrogen-doped (N-doped) carbon nanospheres as graded sulfur reservoirs and conductive frameworks were elaborately designed via a combination of the advantages of hollow structures, 3D electrodes and flexible devices. The as-prepared electrodes by a synergistic method of electrospinning, template sacrificing and activation for Li–S batteries without any binder or conductive additives but a 3D interconnected conductive network offered multiple transport paths for electrons and improved sulfur utilization and facilitated an easy access to Li{sup +} ingress/egress. With the increase of density of hollow carbon spheres in the strings, the self-supporting composite electrode reveals an enhanced synergistic mechanism for sulfur confinement and displays a better cycling stability and rate performance. It delivers a high initial specific capacity of 1422.6 mAh g{sup −1} at the current rate of 0.2C with the high sulfur content of 76 wt.%, and a much higher energy density of 754 Wh kg{sup −1} and power density of 1901 Wh kg{sup −1}, which greatly improve the energy/power density of traditional lithium–sulfur batteries and will be promising for further commercial applications.

  6. Characterizing Microbial Diversity and Function in Natural Subsurface CO2 Reservoir Systems for Applied Use in Geologic Carbon Sequestration Environments

    Freedman, A.; Thompson, J. R.

    2013-12-01

    The injection of CO2 into geological formations at quantities necessary to significantly reduce CO2 emissions will represent an environmental perturbation on a continental scale. The extent to which biological processes may play a role in the fate and transport of CO2 injected into geological formations has remained an open question due to the fact that at temperatures and pressures associated with reservoirs targeted for sequestration CO2 exists as a supercritical fluid (scCO2), which has generally been regarded as a sterilizing agent. Natural subsurface accumulations of CO2 serve as an excellent analogue for studying the long-term effects, implications and benefits of CO2 capture and storage (CCS). While several geologic formations bearing significant volumes of nearly pure scCO2 phases have been identified in the western United States, no study has attempted to characterize the microbial community present in these systems. Because the CO2 in the region is thought to have first accumulated millions of years ago, it is reasonable to assume that native microbial populations have undergone extensive and unique physiological and behavioral adaptations to adjust to the exceedingly high scCO2 content. Our study focuses on the microbial communities associated with the dolomite limestone McElmo Dome scCO2 Field in the Colorado Plateau region, approximately 1,000 m below the surface. Fluid samples were collected from 10 wells at an industrial CO2 production facility outside Cortez, CO. Subsamples preserved on site in 3.7% formaldehyde were treated in the lab with Syto 9 green-fluorescent nucleic acid stain, revealing 3.2E6 to 1.4E8 microbial cells per liter of produced fluid and 8.0E9 cells per liter of local pond water used in well drilling fluids. Extracted DNAs from sterivex 0.22 um filters containing 20 L of sample biomass were used as templates for PCR targeting the 16S rRNA gene. 16S rRNA amplicons from these samples were cloned, sequenced and subjected to microbial

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

    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.

  8. Intra-annual variability of carbon and nitrogen stable isotopes in suspended organic matter in waters of the western continental shelf of India

    M. V. Maya

    2011-11-01

    Full Text Available Intra-annual variations of δ13C and δ15N of water-column suspended particulate organic matter (SPOM have been investigated to understand the biogeochemical cycling of C and N in the Western Continental Shelf of India (WCSI. The key issues being addressed are: how the δ15N of SPOM is affected by seasonally varying processes of organic matter production and respiration and how it relates to the δ15N of sedimentary organic matter that appears to show a decreasing trend despite an apparent intensification of seasonal oxygen deficiency over the past few decades? A secondary objective was to evaluate the sources of organic carbon. Elemental carbon and nitrogen concentrations, C/N ratios in SPOM, along with ancillary chemical and biological variables including phytoplankton pigment abundance were also determined on a seasonal basis (from March 2007 to September 2008, with the partial exception of the southwest (SW monsoon period. The results reveal significant shifts in isotopic signatures, especially δ15N, of SPOM before and after the onset of SW monsoon. Very low δ15N values, reaching a minimum of −4.17 ‰, are found during the pre-monsoon period. Our results provide the first direct evidence for the addition of substantial amounts of isotopically light nitrogen by the diazotrophs, especially Trichodesmium, in the region. The δ15N of SPOM is generally lower than the mean value (7.38 ‰ for surficial sediments, presumably because of diagenetic enrichment. The results support the view that sedimentary δ15N may not necessarily reflect denitrification intensity in the overlying waters due to diverse sources of nitrogen and variability of its isotopic composition. The observed intra-annual variability of δ13C of SPOM during the pre-monsoon and post-monsoon periods is generally small. Phytoplankton production and probably species

  9. LOSCAR: Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir Model v2.0.4

    R. E. Zeebe

    2012-01-01

    Full Text Available The LOSCAR model is designed to efficiently compute the partitioning of carbon between ocean, atmosphere, and sediments on time scales ranging from centuries to millions of years. While a variety of computationally inexpensive carbon cycle models are already available, many are missing a critical sediment component, which is indispensable for long-term integrations. One of LOSCAR's strengths is the coupling of ocean-atmosphere routines to a computationally efficient sediment module. This allows, for instance, adequate computation of CaCO3 dissolution, calcite compensation, and long-term carbon cycle fluxes, including weathering of carbonate and silicate rocks. The ocean component includes various biogeochemical tracers such as total carbon, alkalinity, phosphate, oxygen, and stable carbon isotopes. LOSCAR's configuration of ocean geometry is flexible and allows for easy switching between modern and paleo-versions. We have previously published applications of the model tackling future projections of ocean chemistry and weathering, pCO2 sensitivity to carbon cycle perturbations throughout the Cenozoic, and carbon/calcium cycling during the Paleocene-Eocene Thermal Maximum. The focus of the present contribution is the detailed description of the model including numerical architecture, processes and parameterizations, tuning, and examples of input and output. Typical CPU integration times of LOSCAR are of order seconds for several thousand model years on current standard desktop machines. The LOSCAR source code in C can be obtained from the author by sending a request to loscar.model@gmail.com.

  10. PICOREF: carbon sequestration in geological reservoirs in France.Map of the unknown ''ground motion''. Final report

    Rohmer, J.; Lembezat, C.

    2006-01-01

    in the framework of the PICOREF project, ''CO 2 sequestration in geological reservoirs in France'', two main objectives are decided: the characterization of french adapted sites and the redaction of a document to ask for the storage authorization, including a methodology to survey and study the storage site. This report aims to define the unknown ground motion which the impact should present a risk for the surface installations. The project is presented, as the geological context and the proposed methodology. (A.L.B.)

  11. The Myanmar continental shelf

    Ramaswamy, V.; Rao, P.S.

    reveal a minimum of 18 m thick strata of modern muds (Fig. 2g). At the outer boundary of the Gulf of Myanmar Continental Shelf 8 Martaban (15oN Latitude), brown muds overlie coarse sands indicating that modern deltaic sediments... on the Myeik Bank (Rodolfo, 1969a). Modern sediments on the Ayeyarwady shelf General composition, Texture and Grain-size: The distribution and sediment texture on the Ayeyarwady shelf shows fine-grained sediments comprising silty-clay and clayey...

  12. In-filled reservoirs serving as sediment archives to analyse soil organic carbon erosion – Taking a closer look at the Karoo rangelands

    Krenz, Juliane; Greenwood, Philip; Kuhn, Brigitte

    The semi-arid rangelands of the Great Karoo region in South Africa, which are nowadays characterized by badlands on the foot slopes of upland areas and complex gully systems in valley bottoms, have experienced a number of environmental changes. With the settlement of European farmers in the late ......th century agricultural activities increased, leading to overgrazing which probably acted as a trigger to land degradation. As a consequence of higher water demands and shifting rainfall patterns, many dams and small reservoirs have been constructed to provide drinking water for cattle...... or to facilitate irrigation during dry periods. Most of these dams are now filled with sediment and many have become breached, revealing sediment archives that can be used to analyse land use changes as well as carbon erosion and deposition during the last ca. 100 years. In this ongoing project, a combination...

  13. The Ladbroke Grove-Katnook carbon dioxide natural laboratory: a recent CO{sub 2} accumulation in a lithic sandstone reservoir

    Watson, M.N. [Adelaide Univ., SA (Australia). Australian School of Petroleum; Zwingmann, N. [CSIRO Petroleum, Bentley, WA (Australia); Lemon, N.M. [Santos Ltd., Adelaide, SA (Australia)

    2004-08-01

    The Ladbroke Grove and Katnook Gas Fields, within the western Otway Basin, southeastern South Australia, provide a natural laboratory to study the effects of CO{sub 2} on siliciclastic reservoirs. CO{sub 2} degassing from nearby volcanics has migrated into the methane accumulation of the Ladbroke Grove Field within the Pretty Hill Formation. CO{sub 2} levels in the Ladbroke Grove Field range from 26 to 57 mol% while Katnook has less than 1 mol%. In Ladbroke Grove, the CO{sub 2} has altered or dissolved most of the reactive minerals, somewhat constrained by the Pleistocene to Recent age of the CO{sub 2} influx. The developed late-stage kaolinite, quartz and less soluble carbonate are products of the reactions involving CO{sub 2} and reactive minerals. The major formation water types were identified using the geochemical code EQ3NR. Ladbroke Grove waters above the gas-water contact (GWC) have bicarbonate levels an order of magnitude higher than the other waters analysed. Below the GWC, Ladbroke Grove and Katnook formation waters have similar ionic compositions, however, pH levels in Ladbroke Grove are low relative to Katnook. The Ladbroke Grove Field has efficiently stored CO{sub 2} in a gaseous and aqueous phase since the influx began in the Pleistocene. In addition, due to the high amount of reactive minerals within the reservoir, mineralisation of ferroan carbonates has also occurred as a more permanent form of mineral storage of some of the CO{sub 2}. (author)

  14. Depositional sequence analysis and sedimentologic modeling for improved prediction of Pennsylvanian reservoirs

    Watney, W.L.

    1994-12-01

    Reservoirs in the Lansing-Kansas City limestone result from complex interactions among paleotopography (deposition, concurrent structural deformation), sea level, and diagenesis. Analysis of reservoirs and surface and near-surface analogs has led to developing a {open_quotes}strandline grainstone model{close_quotes} in which relative sea-level stabilized during regressions, resulting in accumulation of multiple grainstone buildups along depositional strike. Resulting stratigraphy in these carbonate units are generally predictable correlating to inferred topographic elevation along the shelf. This model is a valuable predictive tool for (1) locating favorable reservoirs for exploration, and (2) anticipating internal properties of the reservoir for field development. Reservoirs in the Lansing-Kansas City limestones are developed in both oolitic and bioclastic grainstones, however, re-analysis of oomoldic reservoirs provides the greatest opportunity for developing bypassed oil. A new technique, the {open_quotes}Super{close_quotes} Pickett crossplot (formation resistivity vs. porosity) and its use in an integrated petrophysical characterization, has been developed to evaluate extractable oil remaining in these reservoirs. The manual method in combination with 3-D visualization and modeling can help to target production limiting heterogeneities in these complex reservoirs and moreover compute critical parameters for the field such as bulk volume water. Application of this technique indicates that from 6-9 million barrels of Lansing-Kansas City oil remain behind pipe in the Victory-Northeast Lemon Fields. Petroleum geologists are challenged to quantify inferred processes to aid in developing rationale geologically consistent models of sedimentation so that acceptable levels of prediction can be obtained.

  15. Genesis and distribution pattern of carbonate cements in lacustrine deep-water gravity-flow sandstone reservoirs in the third member of the Shahejie Formation in the Dongying Sag, Jiyang Depression, Eastern China

    Yang, Tian; Cao, Yingchang; Friis, Henrik

    2018-01-01

    The lacustrine deep-water gravity-flow sandstone reservoirs in the third member of the Shahejie Formation are the main exploration target for hydrocarbons in the Dongying Sag, Eastern China. Carbonate cementation is responsible for much of the porosity and permeability reduction in the lacustrine...

  16. Heterogeneous Shallow-Shelf Carbonate Buildups in the Paradox Basin, Utah and Colorado: Targets for Increased Oil Production and Reserves Using Horizontal Drilling Techniques; SEMIANNUAL

    Wray, Laura L.; Eby, David E.; Chidsey, Jr. Thomas C.

    2002-01-01

    This report covers research activities for the second half of the second project year (October 6, 2001, through April 5, 2002). This work includes description and analysis of cores, correlation of geophysical well logs, reservoir mapping, petrographic description of thin sections, cross plotting of permeability and porosity data, and development of horizontal drilling strategies for the Little Ute and Sleeping Ute fields in Montezuma County, Colorado. Geological characterization on a local scale focused on reservoir heterogeneity, quality, and lateral continuity, as well as possible compartmentalization, within these fields. This study utilizes representative core, geophysical logs, and thin sections to characterize and grade each field's potential for drilling horizontal laterals from existing development wells

  17. Citrus stand ages regulate the fraction alteration of soil organic carbon under a citrus/Stropharua rugodo-annulata intercropping system in the Three Gorges Reservoir area, China.

    Zhang, Yang; Ni, Jiupai; Yang, John; Zhang, Tong; Xie, Deti

    2017-08-01

    Soil carbon fractionation is a valuable indicator in assessing stabilization of soil organic matter and soil quality. However, limited studies have addressed how different vegetation stand ages under intercropping agroforestry systems, could affect organic carbon (OC) accumulation in bulk soil and its physical fractions. A field study thus investigated the impact of citrus plantation age (15-, 25-, and 45-year citrus) on the bulk soil organic carbon (SOC) and SOC fractions and yields of Stropharia rugoso-annulata (SRA) in the Three Gorges Reservoir area, Chongqing, China. Results indicated that the intercropping practice of SRA with citrus significantly increased the SOC by 57.4-61.6% in topsoil (0-10 cm) and by 24.8-39.9% in subsoil (10-30 cm). With a significantly higher enhancement under the 25-year citrus stand than the other two stands, all these citrus stands of three ages also resulted in a significant increase of free particulate OC (fPOC, 60.1-62.4% in topsoil and 34.8-46.7% in subsoil), intra-micro aggregate particulate OC (iPOC, 167.6-206.0% in topsoil and 2.77-61.09% in subsoil), and mineral-associated OC (MOC, 43.6-46.5% in topsoil and 26.0-51.5% in subsoil). However, there were no significant differences in yields of SRA under three citrus stands. Our results demonstrated that citrus stand ages did play an important role in soil carbon sequestration and fractionation under a citrus/SRA intercropping system, which could therefore provide a sustainable agroforestry system to enhance concurrently the SOC accumulation while mitigating farmland CO 2 emission.

  18. Thermostable Shelf Life Study

    Perchonok, M. H.; Antonini, D. K.

    2008-01-01

    The objective of this project is to determine the shelf life end-point of various food items by means of actual measurement or mathematical projection. The primary goal of the Advanced Food Technology Project in these long duration exploratory missions is to provide the crew with a palatable, nutritious and safe food system while minimizing volume, mass, and waste. The Mars missions could be as long as 2.5 years with the potential of the food being positioned prior to the crew arrival. Therefore, it is anticipated that foods that are used during the Mars missions will require a 5 year shelf life. Shelf life criteria are safety, nutrition, and acceptability. Any of these criteria can be the limiting factor in determining the food's shelf life. Due to the heat sterilization process used for the thermostabilized food items, safety will be preserved as long as the integrity of the package is maintained. Nutrition and acceptability will change over time. Since the food can be the sole source of nutrition to the crew, a significant loss in nutrition may determine when the shelf life endpoint has occurred. Shelf life can be defined when the food item is no longer acceptable. Acceptability can be defined in terms of appearance, flavor, texture, or aroma. Results from shelf life studies of the thermostabilized food items suggest that the shelf life of the foods range from 0 months to 8 years, depending on formulation.

  19. Thermostabilized Shelf Life Study

    Perchonok, Michele H.; Catauro, Patricia M.

    2009-01-01

    The objective of this project is to determine the shelf life end-point of various food items by means of actual measurement or mathematical projection. The primary goal of the Advanced Food Technology Project in these long duration exploratory missions is to provide the crew with a palatable, nutritious and safe food system while minimizing volume, mass, and waste. The Mars missions could be as long as 2.5 years with the potential of the food being positioned prior to the crew arrival. Therefore, it is anticipated that foods that are used during the Mars missions will require a 5 year shelf life. Shelf life criteria are safety, nutrition, and acceptability. Any of these criteria can be the limiting factor in determining the food's shelf life. Due to the heat sterilization process used for the thermostabilized food items, safety will be preserved as long as the integrity of the package is maintained. Nutrition and acceptability will change over time. Since the food can be the sole source of nutrition to the crew, a significant loss in nutrition may determine when the shelf life endpoint has occurred. Shelf life can be defined when the food item is no longer acceptable. Acceptability can be defined in terms of appearance, flavor, texture, or aroma. Results from shelf life studies of the thermostabilized food items suggest that the shelf life of the foods range from 0 months to 8 years, depending on formulation.

  20. Influence of estuaries on shelf sediment texture

    Nair, R.R.; Hashimi, N.H.

    on the coast. Offshore from regions where there are a large number of estuaries, the inner shelf sediments are fine grained (average mean size 5.02 phi, 0.03 mm), rich in organic matter ( 2%) and low in calcium carbonate ( 25%). In contrast, in regions...

  1. INCREASED OIL PRODUCTION AND RESERVES UTILIZING SECONDARY/TERTIARY RECOVERY TECHNIQUES ON SMALL RESERVOIRS IN THE PARADOX BASIN, UTAH

    Thomas C. Chidsey, Jr.

    2002-11-01

    The Paradox Basin of Utah, Colorado, and Arizona contains nearly 100 small oil fields producing from shallow-shelf carbonate buildups or mounds within the Desert Creek zone of the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to four wells with primary production ranging from 700,000 to 2,000,000 barrels (111,300-318,000 m{sup 3}) of oil per field at a 15 to 20 percent recovery rate. Five fields in southeastern Utah were evaluated for waterflood or carbon-dioxide (CO{sub 2})-miscible flood projects based upon geological characterization and reservoir modeling. Geological characterization on a local scale focused on reservoir heterogeneity, quality, and lateral continuity as well as possible compartmentalization within each of the five project fields. The Desert Creek zone includes three generalized facies belts: (1) open-marine, (2) shallow-shelf and shelf-margin, and (3) intra-shelf, salinity-restricted facies. These deposits have modern analogs near the coasts of the Bahamas, Florida, and Australia, respectively, and outcrop analogs along the San Juan River of southeastern Utah. The analogs display reservoir heterogeneity, flow barriers and baffles, and lithofacies geometry observed in the fields; thus, these properties were incorporated in the reservoir simulation models. Productive carbonate buildups consist of three types: (1) phylloid algal, (2) coralline algal, and (3) bryozoan. Phylloid-algal buildups have a mound-core interval and a supra-mound interval. Hydrocarbons are stratigraphically trapped in porous and permeable lithotypes within the mound-core intervals of the lower part of the buildups and the more heterogeneous supramound intervals. To adequately represent the observed spatial heterogeneities in reservoir properties, the phylloid-algal bafflestones of the mound-core interval and the dolomites of the overlying supra-mound interval were subdivided into ten architecturally distinct lithotypes, each of which

  2. Heterogeneous Shallow-Shelf Carbonate Buildups in the Paradox Basin, Utah and Colorado: Targets for Increased Oil Production and Reserves Using Horizontal Drilling Techniques. Semi-Annual Technical Progress Report April 6, 2003 - October 5, 2006

    Thomas C. Chidsey; Kevin McClure; Craig D. Morgan

    2003-01-01

    The Paradox Basin of Utah, Colorado, Arizona, and New Mexico contains nearly 100 small oil fields producing from carbonate buildups within the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to 10 wells with primary production ranging from 700,000 to 2,000,000 barrels (111,300-318,000 m 3 ) of oil per field and a 15 to 20 percent recovery rate. At least 200 million barrels (31.8 million m 3 ) of oil will not be recovered from these small fields because of inefficient recovery practices and undrained heterogeneous reservoirs. Several fields in southeastern Utah and southwestern Colorado are being evaluated as candidates for horizontal drilling and enhanced oil recovery from existing vertical wells based upon geological characterization and reservoir modeling case studies. Geological characterization on a local scale is focused on reservoir heterogeneity, quality, and lateral continuity, as well as possible reservoir compartmentalization, within these fields. This study utilizes representative cores, geophysical logs, and thin sections to characterize and grade each field's potential for drilling horizontal laterals from existing development wells. The results of these studies can be applied to similar fields elsewhere in the Paradox Basin and the Rocky Mountain region, the Michigan and Illinois Basins, and the Midcontinent region. This report covers research activities for the first half of the fourth project year (April 6 through October 5, 2003). The work included (1) analysis of well-test data and oil production from Cherokee and Bug fields, San Juan County, Utah, and (2) diagenetic evaluation of stable isotopes from the upper Ismay and lower Desert Creek zones of the Paradox Formation in the Blanding sub-basin, Utah. Production ''sweet spots'' and potential horizontal drilling candidates were identified for Cherokee and Bug fields. In Cherokee field, the most productive wells are located in the thickest part of the mound facies of

  3. PLAY ANALYSIS AND DIGITAL PORTFOLIO OF MAJOR OIL RESERVOIRS IN THE PERMIAN BASIN: APPLICATION AND TRANSFER OF ADVANCED GEOLOGICAL AND ENGINEERING TECHNOLOGIES FOR INCREMENTAL PRODUCTION OPPORTUNITIES

    Shirley P. Dutton; Eugene M. Kim; Ronald F. Broadhead; Caroline L. Breton; William D. Raatz; Stephen C. Ruppel; Charles Kerans

    2004-05-01

    The Permian Basin of west Texas and southeast New Mexico has produced >30 Bbbl (4.77 x 10{sup 9} m{sup 3}) of oil through 2000, most of it from 1,339 reservoirs having individual cumulative production >1 MMbbl (1.59 x 10{sup 5} m{sup 3}). These significant-sized reservoirs are the focus of this report. Thirty-two Permian Basin oil plays were defined, and each of the 1,339 significant-sized reservoirs was assigned to a play. The reservoirs were mapped and compiled in a Geographic Information System (GIS) by play. Associated reservoir information within linked data tables includes Railroad Commission of Texas reservoir number and district (Texas only), official field and reservoir name, year reservoir was discovered, depth to top of the reservoir, production in 2000, and cumulative production through 2000. Some tables also list subplays. Play boundaries were drawn for each play; the boundaries include areas where fields in that play occur but are <1 MMbbl (1.59 x 10{sup 5} m{sup 3}) of cumulative production. This report contains a summary description of each play, including key reservoir characteristics and successful reservoir-management practices that have been used in the play. The CD accompanying the report contains a pdf version of the report, the GIS project, pdf maps of all plays, and digital data files. Oil production from the reservoirs in the Permian Basin having cumulative production >1 MMbbl (1.59 x 10{sup 5} m{sup 3}) was 301.4 MMbbl (4.79 x 10{sup 7} m{sup 3}) in 2000. Cumulative Permian Basin production through 2000 from these significant-sized reservoirs was 28.9 Bbbl (4.59 x 10{sup 9} m{sup 3}). The top four plays in cumulative production are the Northwest Shelf San Andres Platform Carbonate play (3.97 Bbbl [6.31 x 10{sup 8} m{sup 3}]), the Leonard Restricted Platform Carbonate play (3.30 Bbbl 5.25 x 10{sup 8} m{sup 3}), the Pennsylvanian and Lower Permian Horseshoe Atoll Carbonate play (2.70 Bbbl [4.29 x 10{sup 8} m{sup 3}]), and the San Andres

  4. Hybrid ANFIS with ant colony optimization algorithm for prediction of shear wave velocity from a carbonate reservoir in Iran

    Hadi Fattahi

    2016-12-01

    Full Text Available Shear wave velocity (Vs data are key information for petrophysical, geophysical and geomechanical studies. Although compressional wave velocity (Vp measurements exist in almost all wells, shear wave velocity is not recorded for most of elderly wells due to lack of technologic tools. Furthermore, measurement of shear wave velocity is to some extent costly. This study proposes a novel methodology to remove aforementioned problems by use of hybrid adaptive neuro fuzzy inference system (ANFIS with ant colony optimization algorithm (ACO based on fuzzy c–means clustering (FCM and subtractive clustering (SCM. The ACO is combined with two ANFIS models for determining the optimal value of its user–defined parameters. The optimization implementation by the ACO significantly improves the generalization ability of the ANFIS models. These models are used in this study to formulate conventional well log data into Vs in a quick, cheap, and accurate manner. A total of 3030 data points was used for model construction and 833 data points were employed for assessment of ANFIS models. Finally, a comparison among ANFIS models, and six well–known empirical correlations demonstrated ANFIS models outperformed other methods. This strategy was successfully applied in the Marun reservoir, Iran.

  5. Determination of Pore Pressure from Sonic Log: a Case Study on One of Iran Carbonate Reservoir Rocks

    Morteza Azadpour

    2015-07-01

    Full Text Available Pore pressureis defined as the pressure of the fluid inside the pore space of the formation, which is also known as the formation pressure. When the pore pressure is higher than hydrostatic pressure, it is referred to as overpressure. Knowledge of this pressure is essential for cost-effective drilling, safe well planning, and efficient reservoir modeling. The main objective of this study is to estimate the formation pore pressure as a reliable mud weight pressure using well log data at one of oil fields in the south of Iran. To obtain this goal, the formation pore pressure is estimated from well logging data by applying Eaton’s prediction method with some modifications. In this way, sonic transient time trend line is separated by lithology changes and recalibrated by Weakley’s approach. The created sonic transient time is used to create an overlay pore pressure based on Eaton’s method and is led to pore pressure determination. The results are compared with the pore pressure estimated from commonly used methods such as Eaton’s and Bowers’s methods. The determined pore pressure from Weakley’s approach shows some improvements in comparison with Eaton’s method. However, the results of Bowers’s method, in comparison with the other two methods, show relatively better agreement with the mud weight pressure values.

  6. Mathematical model of the methane replacement by carbon dioxide in the gas hydrate reservoir taking into account the diffusion kinetics

    Musakaev, N. G.; Khasanov, M. K.; Rafikova, G. R.

    2018-03-01

    The problem of the replacement of methane in its hydrate by carbon dioxide in a porous medium is considered. The gas-exchange kinetics scheme is proposed in which the intensity of the process is limited by the diffusion of CO2 through the hydrate layer formed between the gas mixture flow and the CH4 hydrate. Dynamics of the main parameters of the process is numerically investigated. The main characteristic stages of the process are determined.

  7. HETEROGENEOUS SHALLOW-SHELF CARBONATE BUILDUPS IN THE PARADOX BASIN, UTAH AND COLORADO: TARGETS FOR INCREASED OIL PRODUCTION AND RESERVES USING HORIZONTAL DRILLING TECHNIQUES. Semi-Annual Technical Progress Report April 6, 2000 - October 5, 2002

    Chidsey, Thomas C. Jr.

    2002-01-01

    The Paradox Basin of Utah, Colorado, Arizona, and New Mexico contains nearly 100 small oil fields producing from carbonate buildups within the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to 10 wells with primary production ranging from 700,000 to 2,000,000 barrels (111,300-318,000 m 3 ) of oil per field and a 15 to 20 percent recovery rate. At least 200 million barrels (31.8 million m 3 ) of oil will not be recovered from these small fields because of inefficient recovery practices and undrained heterogeneous reservoirs. Several fields in southeastern Utah and southwestern Colorado are being evaluated as candidates for horizontal drilling and enhanced oil recovery from existing, vertical, field wells based upon geological characterization and reservoir modeling case studies. Geological characterization on a local scale is focused on reservoir heterogeneity, quality, and lateral continuity, as well as possible reservoir compartmentalization, within these fields. This study utilizes representative cores, geophysical logs, and thin sections to characterize and grade each field's potential for drilling horizontal laterals from existing development wells. The results of these studies can be applied to similar fields elsewhere in the Paradox Basin and the Rocky Mountain region, the Michigan and Illinois Basins, and the Midcontinent region. This report covers research activities for the first half of the third project year (April 6 through October 5, 2002). This work included capillary pressure/mercury injection analysis, scanning electron microscopy, and pore casting on selected samples from Cherokee and Bug fields, Utah. The diagenetic fabrics and porosity types found at these fields are indicators of reservoir flow capacity, storage capacity, and potential for enhanced oil recovery via horizontal drilling. The reservoir quality of Cherokee and Bug fields has been affected by multiple generations of dissolution, anhydrite plugging

  8. Heterogeneous Shallow-Shelf Carbonate Buildups in the Paradox Basin, Utah and Colorado: Targets for Increased Oil Production and Reserves Using Horizontal Drilling Techniques

    Wray, Laura L.; Eby, David E.; Chidsey, Jr., Thomas C.

    2002-07-24

    This report covers research activities for the second half of the second project year (October 6, 2001, through April 5, 2002). This work includes description and analysis of cores, correlation of geophysical well logs, reservoir mapping, petrographic description of thin sections, cross plotting of permeability and porosity data, and development of horizontal drilling strategies for the Little Ute and Sleeping Ute fields in Montezuma County, Colorado. Geological characterization on a local scale focused on reservoir heterogeneity, quality, and lateral continuity, as well as possible compartmentalization, within these fields. This study utilizes representative core, geophysical logs, and thin sections to characterize and grade each field's potential for drilling horizontal laterals from existing development wells.

  9. Effect of Temperature on Wettability and Optimum Wetting Conditions for Maximum Oil Recovery in Carbonate Reservoir System

    Sohal, Muhammad Adeel Nassar; Thyne, Geoffrey; Søgaard, Erik Gydesen

    2017-01-01

    The additional oil recovery from fractured & oil-wet carbonates by ionically modified water is principally based on changing wettability and often attributed to an improvement in water wetness. The influence of different parameters like dilution of salinity, potential anions, temperature, pressure......, lithology, pH, oil acid and base numbers to improve water wetting has been tested in recovery experiments. In these studies temperature is mainly investigated to observe the reactivity of potential anions (SO42-, PO33-, and BO33-) at different concentrations. But the influence of systematically increasing...... and 100 times. It was observed that as temperature increased the water-wetness decreased for seawater and seawater dilutions, however, the presence of elevated sulfate can somewhat counter this trend as sulfate increased oil wetting....

  10. Application of fluorinated nanofluid for production enhancement of a carbonate gas-condensate reservoir through wettability alteration

    Sakhaei, Zahra; Azin, Reza; Naghizadeh, Arefeh; Osfouri, Shahriar; Saboori, Rahmatollah; Vahdani, Hosein

    2018-03-01

    Condensate blockage phenomenon in near-wellbore region decreases gas production rate remarkably. Wettability alteration using fluorinated chemicals is an efficacious way to vanquish this problem. In this study, new synthesized fluorinated silica nanoparticles with an optimized condition and mean diameter of 50 nm is employed to modify carbonate rock surface wettability. Rock characterization tests consisting Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive x-ray Spectroscopy (EDX) were utilized to assess the nanofluid adsorption on rock surface after treatment. Contact angle, spontaneous imbibition and core flooding experiments were performed to investigate the effect of synthesized nanofluid adsorption on wettability of rock surface and liquid mobility. Results of contact angle experiments revealed that wettability of rock could alter from strongly oil-wetting to the intermediate gas-wetting even at elevated temperature. Imbibition rates of oil and brine were diminished noticeably after treatment. 60% and 30% enhancement in pressure drop of condensate and brine floods after wettability alteration with modified nanofluid were observed which confirm successful field applicability of this chemical.

  11. Dissolved inorganic carbon and alkalinity fluxes from coastal marine sediments: Model estimates for different shelf environments and sensitivity to global change

    Krumins, V.; Gehlen, M.; Arndt, S.; Van Cappellen, P.; Regnier, P.

    2013-01-01

    We present a one-dimensional reactive transport model to estimate benthic fluxes of dissolved inorganic carbon (DIC) and alkalinity (AT) from coastal marine sediments. The model incorporates the transport processes of sediment accumulation, molecular diffusion, bioturbation and bioirrigation,

  12. Relationship between fracturing and porogenesis in a carbonate reservoir: Example from the Middle Turonian Bireno Member in Jebel M'rhila, Central Tunisia

    Haj Ali, Hajer; Belghithi, Hanen; Ouali, Jamel Abdennaceur; Touir, Jamel

    2016-09-01

    The aim of the present work is to study the Middle Turonian carbonate Bireno Member in Jebel M'rhila area (Central Tunisia). This member mainly consists of dolostones. The sampling of the dolomitic rocks was carried out on both sides of the several fractures affecting the Bireno Member. We also measured the directions and dips of the fractures. The Studied dolomites basically consist of subhedral to euhedral dolospar. The porosity associated to the dolomites show a gradual variation both laterally and vertically. In fact, porosity increases respectively, laterally while going toward the fractures and vertically from the bottom to the top of the dolomitic member. The mineralogical and geochemical analyses of dolomite, carried out respectively by X-Ray Diffraction and Atomic Absorption, show that the studied dolomites broadly range from a sub-stoechiometric dolomite (48% CaCO3) far from the fractures to a dolomitic calcite (84% CaCO3) near the fractures. In the same way, the MgCO3 contents vary from 35% to 11%. Such high contents in Ca against low contents in Mg could probably related to the dilution of the dolomitizing marine waters by meteoric waters which would have been introduced within the platform during the Middle Turonian sea-level fall and the subsequent subaerial exposure of the Bireno platform. The Sr and Na contents (respectively, 4 ppm and 15 ppm in average) are rather low and they gradually decrease while approaching the fractures. Such a gradual decrease in Sr and Na concentrations may be the result of salinity lowering caused by the meteoric waters that would have circulated through the existing fractures networks. The previous analyses were supplemented by the SEM examination of the dolomite and the measurement of porosity and permeability. The SEM allowed us to identify the dolomite petrographic phases and the associated diagenetic products (solution, cementing, dedolomitization.), whereas the porosity and permeability evaluation highlights the

  13. Imagerie sismique d'un réservoir carbonaté : le dogger du Bassin parisien Seismic Imaging a Carbonate Reservoir: the Paris Basin Dogger

    Mougenot D.

    2006-11-01

    inversion, 3D interpretation through automatic picking and horizon attributes. The combined use of all these techniques on the Villeperdue (Total operator and Fontaine-au-Bron fields (EAP, operator illustrates the appropriateness of surface seismic for describing the characteristics of the thin reservoir (30 m lying at the top of the Dogger carbonate, at a depth of 1900 m. Widening the frequency content of the seismic comes into conflict with the limitations imposed by the attenuation of the high frequencies as they are propagated in the subsurface. An evaluation of this attenuation, made by VSP, indicates that the filtering related to propagation as far as the Dogger (1. 3 s twt is sharply amplified beyond 90 Hz. High-resolution seismic (2D-HR is used to record this transition frequency at the level of the target, since it provides sufficiently adequate vertical resolution for the reflections at the top and at the base of the reservoir not to interfere (lambda/2 = 26 m. The amplitude of these reflectors is therefore representative of the impedance contrasts on either limit of the reservoir and their lateral variations reveal heterogeneities, such as porosity changes, which are expressed well acoustically. The high frequency content of the 3D seismic (70 Hz was more difficult to enhance. As a result of careful static corrections, which are related to a geological database and uphole surveys, the time-image of the reservoir, at the location of the syncline described by the 3D, is not influenced by the topographic variations and the associated strong surface heterogeneities. Yet the essential contribution made by the 3D, thanks to the continuity of its spatial sampling, is to evidence, via the picking of the reservoir and the corresponding horizon attributes, submeridian lineaments corresponding to faults with throw of several meters which is too weak to be detected on vertical sections. The distribution of these faults, via which water tends to invade the reservoir, and the

  14. Impact of CO2 leakage from sub-seabed carbon dioxide capture and storage (CCS) reservoirs on benthic virus-prokaryote interactions and functions.

    Rastelli, Eugenio; Corinaldesi, Cinzia; Dell'Anno, Antonio; Amaro, Teresa; Queirós, Ana M; Widdicombe, Stephen; Danovaro, Roberto

    2015-01-01

    Atmospheric CO2 emissions are a global concern due to their predicted impact on biodiversity, ecosystems functioning, and human life. Among the proposed mitigation strategies, CO2 capture and storage, primarily the injection of CO2 into marine deep geological formations has been suggested as a technically practical option for reducing emissions. However, concerns have been raised that possible leakage from such storage sites, and the associated elevated levels of pCO2 could locally impact the biodiversity and biogeochemical processes in the sediments above these reservoirs. Whilst a number of impact assessment studies have been conducted, no information is available on the specific responses of viruses and virus-host interactions. In the present study, we tested the impact of a simulated CO2 leakage on the benthic microbial assemblages, with specific focus on microbial activity and virus-induced prokaryotic mortality (VIPM). We found that exposure to levels of CO2 in the overlying seawater from 1,000 to 20,000 ppm for a period up to 140 days, resulted in a marked decrease in heterotrophic carbon production and organic matter degradation rates in the sediments, associated with lower rates of VIPM, and a progressive accumulation of sedimentary organic matter with increasing CO2 concentrations. These results suggest that the increase in seawater pCO2 levels that may result from CO2 leakage, can severely reduce the rates of microbial-mediated recycling of the sedimentary organic matter and viral infections, with major consequences on C cycling and nutrient regeneration, and hence on the functioning of benthic ecosystems.

  15. [Characteristics of dissolved organic carbon release under inundation from typical grass plants in the water-level fluctuation zone of the Three Gorges Reservoir area].

    Tan, Qiu-Xia; Zhu, Boi; Hua, Ke-Ke

    2013-08-01

    The water-level fluctuation zone of the Three Gorges Reservoir (TGR) exposes in spring and summer, then, green plants especially herbaceous plants grow vigorously. In the late of September, water-level fluctuation zone of TGR goes to inundation. Meanwhile, annually accumulated biomass of plant will be submerged for decaying, resulting in organism decomposition and release a large amount of dissolved organic carbon (DOC). This may lead to negative impacts on water environment of TGR. The typical herbaceous plants from water-level fluctuation zone were collected and inundated in the laboratory for dynamic measurements of DOC concentration of overlying water. According to the determination, the DOC release rates and fluxes have been calculated. Results showed that the release process of DOC variation fitted in a parabolic curve. The peak DOC concentrations emerge averagely in the 15th day of inundation, indicating that DOC released quickly with organism decay of herbaceous plant. The release process of DOC could be described by the logarithm equation. There are significant differences between the concentration of DOC (the maximum DOC concentration is 486.88 mg x L(-1) +/- 35.97 mg x L(-1) for Centaurea picris, the minimum is 4.18 mg x L(-1) +/- 1.07 mg x L(-1) for Echinochloacrus galli) and the release amount of DOC (the maximum is 50.54 mg x g(-1) for Centaurea picris, the minimum is 6.51 mg x g(-1) for Polygonum hydropiper) due to different characteristics of plants, especially, the values of C/N of herbaceous plants. The cumulative DOC release quantities during the whole inundation period were significantly correlated with plants' C/N values in linear equations.

  16. Development and application of a new biotechnology of the molasses in-situ method; detailed evaluation for selected wells in the Romashkino carbonate reservoir

    Wagner, M.; Lungerhausen, D. [Erdoel-Erdgas Gommern GmbH (Germany); Murtada, H.; Rosenthal, G. [VEBA OEL AG, Gelsenkirchen (Germany)

    1995-12-31

    On the basis of different laboratory studies, by which special strains of the type Clostridium tyrobutyricum were found, the application of molasses in-situ method for the enhanced recovery of oil in Romashkino oil field was executed. In an anaerobic, 6%-molasses medium the strains produce about 11,400 mg/l of organic acids (especially butyric acid), 3,200 mg/l ethanol, butanol, etc., and more than 350 ml/g of molasses biogas with a content of 80% C0{sub 2} and 20% H{sub 2}. The metabolics of Clostridium tyrobutyricum depress the growth of SRB, whereas methanogenic bacteria grow in an undiluted fermented molasses medium very well. In this way the dominant final fermentation process is methanogenesis. By laboratory studies with original cores under the conditions of the carbonate reservoir in Bashkir, the recovery of oil increased from 15% after waterflooding to 29% OOIP during the treatment with molasses and bacteria. We developed a new biotechnological method for a self-regulated, automatic continuous culture and constructed a special pilot plant with a high technical standard. The plant produced during the pilot on Romashkino field (September 1992 to August 1994) about 1,000 m{sup 3} of clean inoculum with a content of 3-4 billion cells per ml. This inoculum was injected in slugs together with 15,000 m{sup 3} of molasses medium, first in one, later in five wells. We will demonstrate for two example wells the complex microbiological and chemical changes in the oil, gas, and water phases, and their influences on the recover of oil.

  17. Reservoir effects in radiocarbon dating

    Head, M.J.

    1997-01-01

    Full text: The radiocarbon dating technique depends essentially on the assumption that atmospheric carbon dioxide containing the cosmogenic radioisotope 14 C enters into a state of equilibrium with all living material (plants and animals) as part of the terrestrial carbon cycle. Terrestrial reservoir effects occur when the atmospheric 14 C signal is diluted by local effects where systems depleted in 14 C mix with systems that are in equilibrium with the atmosphere. Naturally, this can occur with plant material growing close to an active volcano adding very old CO 2 to the atmosphere (the original 14 C has completely decayed). It can also occur in highly industrialised areas where fossil fuel derived CO 2 dilutes the atmospheric signal. A terrestrial reservoir effect can occur in the case of fresh water shells living in rivers or lakes where there is an input of ground water from springs or a raising of the water table. Soluble bicarbonate derived from the dissolution of very old limestone produces a 14 C dilution effect. Land snail shells and stream carbonate depositions (tufas and travertines) can be affected by a similar mechanism. Alternatively, in specific cases, these reservoir effects may not occur. This means that general interpretations assuming quantitative values for these terrestrial effects are not possible. Each microenvironment associated with samples being analysed needs to be evaluated independently. Similarly, the marine environment produces reservoir effects. With respect to marine shells and corals, the water depth at which carbonate growth occurs can significantly affect quantitative 14 C dilution, especially in areas where very old water is uplifted, mixing with top layers of water that undergo significant exchange with atmospheric CO 2 . Hence, generalisations with respect to the marine reservoir effect also pose problems. These can be exacerbated by the mixing of sea water with either terrestrial water in estuaries, or ground water where

  18. Outer Continental Shelf Lands Act

    National Oceanic and Atmospheric Administration, Department of Commerce — This data represents geographic terms used within the Outer Continental Shelf Lands Act (OCSLA or Act). The Act defines the United States outer continental shelf...

  19. Modern sedimentary processes along the Doce river adjacent continental shelf

    Valéria da Silva Quaresma

    Full Text Available In areas of the continental shelf where sediment supply is greater than the sediment dispersion capacity, an extensive terrigenous deposits and consequently submerged deltas can be formed. The Eastern Brazilian shelf is characterized by the occurrence of river feed deltas in between starving coasts. Herein, modern sedimentary processes acting along the Doce river adjacent continental shelf are investigated. The main objective was to understand the shelf sediment distribution, recognizing distinct sedimentary patterns and the major influence of river sediment discharge in the formation of shelf deposits. The study used 98 surficial samples that were analyzed for grain size, composition and bulk density. Results revealed 3 distinct sectors: south - dominated by mud fraction with a recent deposition from riverine input until 30 m deep and from this depth bioclastic sands dominate; central north - sand mud dominated, been recognized as a bypass zone of resuspended sediment during high energy events; and north - relict sands with high carbonate content. The modern sedimentation processes along the Doce river continental shelf is dominated by distinct sedimentary regimes, showing a strong fluvial influence associated with wave/wind induced sediment dispersion and a carbonate regime along the outer shelf. These regimes seem to be controlled by the distance from the river mouth and bathymetric gradients.

  20. Fluid circulation and diagenesis of carbonated and sandstone reservoirs in the fronts and fore-lands of folded chains: the Salt Range case - Poswar (Pakistan); Circulation des fluides et diagenese des reservoirs carbonates et greseux dans les fronts de chaines plissees et leur avant pays: le cas du Salt Range - Poswar (Pakistan)

    Benchilla, L.

    2003-05-01

    The Salt Range-Poswar Province is located in the western foothills of the Himalayas, in northern Pakistan. It extends over 170 km from the Main Boundary Thrust (MBT) in the north to the Salt Range in the south. The Salt Range itself is dominantly an ENE-trending structure, but it comprises also a NNW-trending lateral ramp which connects to the west with the Surghar Range. The Salt Range constitutes the frontal part of a detached allochthonous thrust sheet. The sedimentary cover is indeed entirely detached from its substratum along Infracambrian salt horizons. Palaeozoic to Eocene platform series are well exposed in the hanging wall, whereas Neogene molasse has been extensively under-thrust in the footwall of this large over-thrust. The North Potwar Basin is bordered by the Khari-Murat Ridge and coeval back-thrusts in the south, by the northern flank of the Soan syncline in the southeast, and by the MBT in the north. In addition to Neogene outcrops, it also comprises a number of surface anticlines and thrust fronts along which the Eocene platform carbonates are exposed. The Datta Formation is the main Jurassic oil reservoir in the Potwar Basin. It is a fluvio-deltaic deposit which comprises large porous and permeable channels associated to many-calcareous interbeds. The formations crop out well in both the Nammal and Chichali Gorges. The oil field of Toot, located in the western part of the basin, is producing from this reservoir. The petrographic observations show that diagenesis occurred mainly early and was controlled by the fluvio-deltaic environment. (author)

  1. Quantitative geochemical modeling along a transect off Peru: Carbon cycling in time and space, and the triggering factors for carbon loss and storage

    Arning, Esther T.; van Berk, Wolfgang; Schulz, Hans-Martin

    2012-12-01

    Early diagenetic processes in Peruvian shelf and slope sediments are numerically reproduced by applying chemical thermodynamics in a complex, universal approach using the PHREEQC (version 2) computer code. The reaction kinetics of organic carbon remineralization are integrated into a set of equilibrium reactions by defining the type and the amount of converted organic matter in a certain time step. We calculate the most intense remineralization of organic carbon for present-day shelf sites, and the final carbon pool is dominated by secondary carbonates. This serves to highlight the influence of organic matter degradation and anaerobic oxidation of methane (AOM) on diagenetic mineral formation. The enrichment of aqueous methane and the formation of methane hydrate only takes place in slope sediments with high sedimentation rates that prevent diffusive loss of methane (e.g., Sites 682 and 688). Moreover, AOM prevents the diffusion of dissolved methane into overlying seawater. Throughout the Miocene period, these sites were located on a former shelf and the total carbon loss from the sediments was significantly higher in comparison with the present-day. Compared with the present-day shelf site, organic matter remineralization is high, and methane is produced but not stored within the sediments. Our model calculations rule out the possibility of present-day and former shelf site sediments off the coast of Peru as methane reservoirs. Remineralized TOC has to be considered, particularly in older sediments, when interpreting TOC profiles and calculating mass accumulation rates of total organic carbon (MARTOC). The more organic matter has been remineralized during the depositional history, the larger the difference between MARTOC calculated from measured TOC data, and from the sum of modeled and measured TOC data. Consequently, most reliable primary productivity calculations are based on the sum of measured relict TOC and the amount of remineralized organic carbon

  2. The influence of nanoflagellates on the spatial variety of picoplankton and the carbon flow of the microbial food web in the oligotrophic subtropical pelagic continental shelf ecosystem

    Chiang, Kuo-Ping; Tsai, An-Yi; Tsai, Pei-Jung; Gong, Gwo-Ching; Huang, Bang-Qin; Tsai, Sheng-Fang

    2014-06-01

    To investigate the mechanism of the spatial dynamics of picoplankton community (bacteria and Synechococcus spp.) and to estimate the carbon flux of the microbial food web in the oligotrophic Taiwan Warm Current Water of the subtropical marine pelagic ecosystem, we conducted size-fractionation experiments during five cruises by the R/V Ocean Research II during the summers of 2010 and 2011 in the southern East China Sea. We carried out culture experiments using surface water, which according to a temperature-salinity (T-S) diagram, is characterized as oligotrophic Taiwan Current Warm Water. We found a negative correlation between bacteria growth rate and temperature, and another negative correlation between nitrate and temperature indicating that the active growth of heterotrophic bacteria might be induced by nutrients lifted from a deep layer by cold upwelling water. This finding suggests that the area we studied was a bottom-up control pelagic ecosystem. Upwelling brings nutrient-rich water to the euphotic zone and promotes bacterial growth, resulting in increased picoplankton biomass, which increases the consumption rate of nanoflagellates. The net growth rate (growth rate-grazing rate) becomes negative when the densities of bacteria and Synechococcus spp. are lower than the threshold values. The interaction between growth and grazing will limit the abundance of bacteria (105-106 cells ml-1) and Synechococcus spp. (104-105 cells ml-1) within a narrow range. Meanwhile, 61% of bacteria production and 54% of Synechococcus spp. production are transported to a higher trophic level (nanoflagellate), though the cascade effect might cause an underestimation of both percentages of transported carbon. Based on the successive size-fractionation experiments, we estimated that the predation values were underestimated and that the diet of nanoflagellates is composed of 64% bacteria and 36% Synechococcus spp.

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

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

    2000-03-16

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

  4. Coupling of the spatial dynamic of picoplankton and nanoflagellate grazing pressure and carbon flow of the microbial food web in the subtropical pelagic continental shelf ecosystem

    Chiang, K.-P.; Tsai, A.-Y.; Tsai, P.-J.; Gong, G.-C.; Tsai, S.-F.

    2013-01-01

    In order to investigate the mechanism of spatial dynamics of picoplankton community (bacteria and Synechococcus spp.) and estimate the carbon flux of the microbial food web in the oligotrophic Taiwan Warm Current Water of subtropical marine pelagic ecosystem, we conducted size-fractionation experiments in five cruises by the R/V Ocean Research II during the summers of 2010 and 2011 in the southern East China Sea. We carried out culture experiments using surface water which, according to a temperature-salinity (T-S) diagram, is characterized as oligotrophic Taiwan Current Warm Water. We found a negative correlation bettween bacteria growth rate and temperature, indicating that the active growth of heterotrophic bacteria might be induced by nutrients lifted from deep layer by cold upwelling water. This finding suggests that the area we studied was a bottom-up control pelagic ecosystem. We suggest that the microbial food web of an oligotrophic ecosystem may be changed from top-down control to resource supply (bottom-up control) when a physical force brings nutrient into the oligotrophic ecosystem. Upwelling brings nutrient-rich water to euphotic zone and promotes bacteria growth, increasing the picoplankton biomass which increased the consumption rate of nanoflagellate. The net growth rate (growth rate-grazing rate) becomes negative when the densities of bacteria and Synechococcus spp. are lower than the threshold values. The interaction between growth and grazing will limit the abundances of bacteria (105-106 cells mL-1 and Synechococcus spp. (104-105 cells mL-1) within a narrow range, forming a predator-prey eddy. Meanwhile, 62% of bacteria production and 55% of Synechococcus spp. production are transported to higher trophic level (nanoflagellate), though the cascade effect might cause an underestimation of both percentages of transported carbon. Based on the increasing number of sizes we found in the size-fractionation experiments, we estimated that the predation

  5. Increased Oil Production and Reserves Utilizing Secondary/Tertiary Recovery Techniques on Small Reservoirs in the Paradox Basin, Utah

    Chidsey Jr., Thomas C.

    2003-01-01

    The primary objective of this project was to enhance domestic petroleum production by field demonstration and technology transfer of an advanced-oil-recovery technology in the Paradox Basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to approximately 100 additional small fields in the Paradox Basin alone, and result in increased recovery of 150 to 200 million barrels (23,850,000-31,800,000 m3) of oil. This project was designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon-dioxide-(CO2-) miscible flood project. The field demonstration, monitoring of field performance, and associated validation activities will take place within the Navajo Nation, San Juan County, Utah

  6. Increased Oil Production and Reserves Utilizing Secondary/Tertiary Recovery Techniques on Small Reservoirs in the Paradox Basin, Utah; ANNUAL

    Jr., Chidsey, Thomas C.; Allison, M. Lee

    1999-01-01

    The primary objective of this project is to enhance domestic petroleum production by field demonstration and technology transfer of an advanced- oil-recovery technology in the Paradox basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to approximately 100 additional small fields in the Paradox basin alone, and result in increased recovery of 150 to 200 million barrels (23,850,000-31,800,000 m3) of oil. This project is designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon-dioxide-(CO2-) miscible flood project. The field demonstration, monitoring of field performance, and associated validation activities will take place within the Navajo Nation, San Juan County, Utah

  7. Roosevelt Island Climate Evolution Project (RICE): A 65 Kyr ice core record of black carbon aerosol deposition to the Ross Ice Shelf, West Antarctica.

    Edwards, Ross; Bertler, Nancy; Tuohy, Andrea; Neff, Peter; Proemse, Bernedette; Feiteng, Wang; Goodwin, Ian; Hogan, Chad

    2015-04-01

    Emitted by fires, black carbon aerosols (rBC) perturb the atmosphere's physical and chemical properties and are climatically active. Sedimentary charcoal and other paleo-fire records suggest that rBC emissions have varied significantly in the past due to human activity and climate variability. However, few paleo rBC records exist to constrain reconstructions of the past rBC atmospheric distribution and its climate interaction. As part of the international Roosevelt Island Climate Evolution (RICE) project, we have developed an Antarctic rBC ice core record spanning the past ~65 Kyr. The RICE deep ice core was drilled from the Roosevelt Island ice dome in West Antarctica from 2011 to 2013. The high depth resolution (~ 1 cm) record was developed using a single particle intracavity laser-induced incandescence soot photometer (SP2) coupled to an ice core melter system. The rBC record displays sub-annual variability consistent with both austral dry-season and summer biomass burning. The record exhibits significant decadal to millennial-scale variability consistent with known changes in climate. Glacial rBC concentrations were much lower than Holocene concentrations with the exception of several periods of abrupt increases in rBC. The transition from glacial to interglacial rBC concentrations occurred over a much longer time relative to other ice core climate proxies such as water isotopes and suggests . The protracted increase in rBC during the transition may reflected Southern hemisphere ecosystem / fire regime changes in response to hydroclimate and human activity.

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

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

    2018-04-01

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

  9. Tectono-Thermal History Modeling and Reservoir Simulation Study of the Nenana Basin, Central Alaska: Implications for Regional Tectonics and Geologic Carbon Sequestration

    Dixit, Nilesh C.

    Central Interior Alaska is an active tectonic deformation zone highlighted by the complex interactions of active strike-slip fault systems with thrust faults and folds of the Alaska Range fold-and-thrust belt. This region includes the Nenana basin and the adjacent Tanana basin, both of which have significant Tertiary coal-bearing formations and are also promising areas (particularly the Nenana basin) with respect to hydrocarbon exploration and geologic carbon sequestration. I investigate the modern-day crustal architecture of the Nenana and Tanana basins using seismic reflection, aeromagnetic and gravity anomaly data and demonstrate that the basement of both basins shows strong crustal heterogeneity. The Nenana basin is a deep (up to 8 km), narrow transtensional pull-apart basin that is deforming along the left-lateral Minto Flats fault zone. The Tanana basin has a fundamentally different geometry and is a relatively shallow (up to 2 km) asymmetrical foreland basin with its southern, deeper side controlled by the northern foothills of the central Alaska Range. NE-trending strike-slip faults within the Tanana basin are interpreted as a zone of clockwise crustal block rotation. Seismic refection data, well data, fracture data and apatite fission track data further constrain the tectonic evolution and thermal history of the Nenana basin. The Nenana basin experienced four distinct tectonic phases since Late Paleocene time. The basin initiated as a narrow half-graben structure in Late Paleocene with accumulation of greater than 6000 feet of sediments. The basin was then uplifted, resulting in the removal of up to 5000 feet of Late Paleocene sediments in Eocene to Oligocene time. During Middle to Late Miocene time, left lateral strike-slip faulting was superimposed on the existing half-graben system. Transtensional deformation of the basin began in the Pliocene. At present, Miocene and older strata are exposed to temperatures > 60°C in the deeper parts of the Nenana

  10. Transport and transfer rates in the waters of the continental shelf and slope: SEEP

    Biscaye, P.E.; Anderson, R.F.

    1993-01-01

    The overall Shelf Edge Exchange Processes (SEEP) Program, which began in 1980 or 1981, had as its goal the testing of a hypothesis with respect to the fate of particulate matter formed in and introduced into the waters of the continental shelf adjacent to the northern east coast of the US, i.e., the MAB. The original hypothesis was that a large proportion of the particles in general, and of the particulate organic carbon (POC) in particular, was exported from the shelf, across the shelf/slope break and front, into the waters of, and, to some degree, deposited in the sediments of the continental slope. This hypothesis was based on budgets of organic carbon and lead-210 that did not account for a large proportion of those species in the waters or sediments of the shelf, and on a carbon-rich band of sediments centered on the slope at ∼1,000 m water depth. The results of the first SEEP experiment, south of New England and Long Island (SEEP-1) suggested, but did not prove, that there was only a relatively small proportion of the carbon which was exported from the shelf to the slope. The objective of the second experiment -- SEEP-2 -- done under the subject grant, was to tighten the experiment in terms of the kinds of data collected, and to focus it more on the shelf and only the upper slope, where shelf-derived particles were thought to be deposited

  11. The freshwater reservoir effect in radiocarbon dating

    Philippsen, Bente

    2013-01-01

    of magnitude and degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants, and animals, shows that age differences of up to 2000 14C years can occur within one river. The freshwater reservoir effect has also implications......The freshwater reservoir effect can result in anomalously old radiocarbon ages of samples from lakes and rivers. This includes the bones of people whose subsistence was based on freshwater fish, and pottery in which fish was cooked. Water rich in dissolved ancient calcium carbonates, commonly known...... as hard water, is the most common reason for the freshwater reservoir effect. It is therefore also called hardwater effect. Although it has been known for more than 60 years, it is still less well-recognized by archaeologists than the marine reservoir effect. The aim of this study is to examine the order...

  12. Distribution of some biochemical compounds in sediments of the shelf and slope regions of the west coast of India

    Bhosle, N.B.; Dhargalkar, V.K.; Braganca, A.

    Surficial sediment samples collected from the continental shelf and slope of the Bay of Bengal were studied for the distribution of organic carbon and its constituent fractions such as carbohydrates, proteins, amino acids and lipids. Organic carbon...

  13. The carbon budget of the North Sea

    Thomas, H.; Bozec, Y.; Baar, H.J.W. de; Elkalay, K.; Frankignoulle, M.; Schiettecatte, L.-S.; Kattner, G.; Borges, A.V.; Gattuso, J.-P.

    2005-01-01

    A carbon budget has been established for the North Sea, a shelf sea on the NW European continental shelf. The carbon exchange fluxes with the North Atlantic Ocean dominate the gross carbon budget. The net carbon budget – more relevant to the issue of the contribution of the coastal ocean to the

  14. New Jersey shallow shelf

    Expedition 313 Scientists; Bjerrum, Christian J.

    2009-01-01

    to key horizons in wells drilled into the adjacent coastal plain suggest the clinoform structures investigated during Expedition 313 were deposited during times of oscillations in global sea level; however, this needs to be determined with much greater certainty. The age, lithofacies, and core-log......Integrated Ocean Drilling Program (IODP) Expedition 313 to the New Jersey Shallow Shelf off the east coast of the United States is the third IODP expedition to use a mission-specific platform. It was conducted by the European Consortium for Ocean Research Drilling (ECORD) Science Operator (ESO......) between 30 April and 17 July 2009, with additional support from the International Continental Scientific Drilling Program (ICDP). There were three objectives: (1) date late Paleogene–Neogene depositional sequences and compare ages of unconformable surfaces that divide these sequences with times of sea...

  15. Accelerated Shelf Life Testing of Jackfruit Extract Powder

    Enny Hawani Loebis

    2013-06-01

    Full Text Available Jackfruit is a potential tropical fruit as raw material for food industry. Jackfruit could be processed by co-crystallization technique to extend its shelf life and increase its value. This research was conducted to study and to determine the shelf life of jackfruit powder extract. Shelf life test is conducted using variety of treatments such as: anti-caking types and temperature storage. The results showed that the shelf life of the jackfruit extract powder using anti-caking of magnesium oxide (MO, magnesium carbonate (MC, dan magnesium silicate (MS, which is store in the temperature of 27°C, were: 8.06, 5.42, and 5.5 months respectively. The variation of anti-caking type was significantly affect the product shelf life.  The effect of storage temperature on the product shelf life is more significant for the product using anti-caking MO compared with product using anti-caking MC and MS.

  16. Surficial sediments of the continental shelf off Karnataka

    Hashimi, N.H.; Nair, R.R.

    sediments occur betweenthe water depths of 15 to 50m corresponding to a distance of about 40 km from the coast. Beyond 50 m to the shelf edge are calcareous sands. Non-carbonate components of these deep water sands are essentially quartz, many of which...

  17. Spatiotemporal sedimentological and petrophysical characterization of El Gueria reservoir (Ypresian) in sFAX and Gulf of Gabes Basins (SE-Tunisia)

    Nadhem, Kassabi; Zahra, Njahi; Ménendez, Béatriz; Salwa, Jeddi; Jamel, Touir

    2017-06-01

    El Gueria carbonate Formation (Ypresian) in Tunisia is a proven hydrocarbon reservoir. In the Gulf of Gabes, El Gueria reservoir consists mainly of a nummulitic limestone which is developed in an inner shelf environment. In order to characterize the depositional facies evolution and the petrophysical parameters, and to understand the origin of heterogeneity of El Gueria reservoir, we firstly conducted a sedimentological and a sequence stratigraphy study of this Formation in more than 10 wells especially in P1, then we established a detailed petrophysical study of El Gueria reservoir in P1, P3c and P7d cores. Based on lithostratigraphic and gamma ray correlations of an important number of wells in the study area, a detailed sedimentological study has been established. This latter shows that: (i): The Ypresien deposits are deposited in an inner shelf (El Gueria Formation) in the south and in an outer shelf (Boudabbous Formation) in the north of the study area with the form of horsts and grabens, (ii): 3 distinct members and 7 principal facies within El Gueria Formation have been distinguished. The coupling of data logging and data of the P1 core shows that the El Gueria deposits include 10 transgressive-regressive depositional sequences, while showing from bottom to top a broad regressive tendancy from a subtidal domain during the early Ypresian to an intertidal domain during the middle Ypresian reaching the supratidal environnement during the late Ypresian-early Lutetian. The petrophysical parameters (porosity and permeability) of El Gueria reservoir vary in time and space (laterally and vertically variation) following the deposit environment variation. Particularly, the porosity variation is controlled by eustatic cycles so that high porosities are linked with transgressive phases and low porosities with regressive phases. In addition, the vertical evolution of porosity through the El Gueria reservoir varies following the (i) deposit environments, (ii) type and

  18. Optimizing and Quantifying CO2 Storage Resource in Saline Formations and Hydrocarbon Reservoirs

    Bosshart, Nicholas W. [Univ. of North Dakota, Grand Folks, ND (United States). Energy & Environmental Research Center; Ayash, Scott C. [Univ. of North Dakota, Grand Folks, ND (United States). Energy & Environmental Research Center; Azzolina, Nicholas A. [Univ. of North Dakota, Grand Folks, ND (United States). Energy & Environmental Research Center; Peck, Wesley D. [Univ. of North Dakota, Grand Folks, ND (United States). Energy & Environmental Research Center; Gorecki, Charles D. [Univ. of North Dakota, Grand Folks, ND (United States). Energy & Environmental Research Center; Ge, Jun [Univ. of North Dakota, Grand Folks, ND (United States). Energy & Environmental Research Center; Jiang, Tao [Univ. of North Dakota, Grand Folks, ND (United States). Energy & Environmental Research Center; Burton-Kelly, Matthew E. [Univ. of North Dakota, Grand Folks, ND (United States). Energy & Environmental Research Center; Anderson, Parker W. [Univ. of North Dakota, Grand Folks, ND (United States). Energy & Environmental Research Center; Dotzenrod, Neil W. [Univ. of North Dakota, Grand Folks, ND (United States). Energy & Environmental Research Center; Gorz, Andrew J. [Univ. of North Dakota, Grand Folks, ND (United States). Energy & Environmental Research Center

    2017-06-30

    In an effort to reduce carbon dioxide (CO2) emissions from large stationary sources, carbon capture and storage (CCS) is being investigated as one approach. This work assesses CO2 storage resource estimation methods for deep saline formations (DSFs) and hydrocarbon reservoirs undergoing CO2 enhanced oil recovery (EOR). Project activities were conducted using geologic modeling and simulation to investigate CO2 storage efficiency. CO2 storage rates and efficiencies in DSFs classified by interpreted depositional environment were evaluated at the regional scale over a 100-year time frame. A focus was placed on developing results applicable to future widespread commercial-scale CO2 storage operations in which an array of injection wells may be used to optimize storage in saline formations. The results of this work suggest future investigations of prospective storage resource in closed or semiclosed formations need not have a detailed understanding of the depositional environment of the reservoir to generate meaningful estimates. However, the results of this work also illustrate the relative importance of depositional environment, formation depth, structural geometry, and boundary conditions on the rate of CO2 storage in these types of systems. CO2 EOR occupies an important place in the realm of geologic storage of CO2, as it is likely to be the primary means of geologic CO2 storage during the early stages of commercial implementation, given the lack of a national policy and the viability of the current business case. This work estimates CO2 storage efficiency factors using a unique industry database of CO2 EOR sites and 18 different reservoir simulation models capturing fluvial clastic and shallow shelf carbonate depositional environments for reservoir depths of 1219 and 2438 meters (4000 and 8000 feet) and 7.6-, 20-, and 64-meter (25-, 66

  19. Short term variation in particulate matter in the shelf waters of the Princess Astrid Coast, Antarctica

    Dhargalkar, V.K.; Bhosle, N.B.

    Particulate matter collected at a single station in the shelf waters of Princess Astrid coast (70 degrees S, 11 degrees E) Antarctica, during the austral summer (Jan.-Feb. 1986) was analysed for phytoplankton biomass (Chl @ia@@), living carbon (ATP...

  20. INTELLIGENT COMPUTING SYSTEM FOR RESERVOIR ANALYSIS AND RISK ASSESSMENT OF THE RED RIVER FORMATION

    Mark A. Sippel; William C. Carrigan; Kenneth D. Luff; Lyn Canter

    2003-11-12

    Integrated software has been written that comprises the tool kit for the Intelligent Computing System (ICS). The software tools in ICS have been developed for characterization of reservoir properties and evaluation of hydrocarbon potential using a combination of inter-disciplinary data sources such as geophysical, geologic and engineering variables. The ICS tools provide a means for logical and consistent reservoir characterization and oil reserve estimates. The tools can be broadly characterized as (1) clustering tools, (2) neural solvers, (3) multiple-linear regression, (4) entrapment-potential calculator and (5) file utility tools. ICS tools are extremely flexible in their approach and use, and applicable to most geologic settings. The tools are primarily designed to correlate relationships between seismic information and engineering and geologic data obtained from wells, and to convert or translate seismic information into engineering and geologic terms or units. It is also possible to apply ICS in a simple framework that may include reservoir characterization using only engineering, seismic, or geologic data in the analysis. ICS tools were developed and tested using geophysical, geologic and engineering data obtained from an exploitation and development project involving the Red River Formation in Bowman County, North Dakota and Harding County, South Dakota. Data obtained from 3D seismic surveys, and 2D seismic lines encompassing nine prospective field areas were used in the analysis. The geologic setting of the Red River Formation in Bowman and Harding counties is that of a shallow-shelf, carbonate system. Present-day depth of the Red River formation is approximately 8000 to 10,000 ft below ground surface. This report summarizes production results from well demonstration activity, results of reservoir characterization of the Red River Formation at demonstration sites, descriptions of ICS tools and strategies for their application.

  1. SILTATION IN RESERVOIRS

    Keywords: reservoir model, siltation, sediment, catchment, sediment transport. 1. Introduction. Sediment ... rendered water storage structures useless in less than 25 years. ... reservoir, thus reducing the space available for water storage and ...

  2. Reservoir fisheries of Asia

    Silva, S.S. De.

    1990-01-01

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

  3. Large reservoirs: Chapter 17

    Miranda, Leandro E.; Bettoli, Phillip William

    2010-01-01

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

  4. Sources, Fate and Distribution of Organic Matter on the Western Adriatic Continental Shelf, Italy

    Tesi, Tommaso; Miserocchi, Stefano; Langone, Leonardo; Boni, Laurita; Guerrini, Franca

    2006-01-01

    In the framework of the EUROSTRATAFORM projects, a multidisciplinary research was focused on processes that involve transport and deposition of riverine material in the Adriatic Sea. The aim of our contribution was to increase a more complete understanding of organic matter deposition on the Adriatic shelf, also taking into account the role of Apennine rivers beyond the Po influence. In order to characterize origin, fate and variability of sedimentary organic carbon we utilized elemental and stable carbon isotope data in surficial sediments along shallow cross-shelf transects on the western Adriatic shelf

  5. Risk and geological uncertainties in carbonate reservoirs in Santos Basin; Incertezas geologicas e risco em reservatorios carbonaticos na Bacia de Santos

    Saito, Makoto; Cortez, Marcella M.M. [Queiroz Galvao Perfuracoes S.A., Rio de Janeiro, RJ (Brazil); Mendes, Marcos Huber

    2004-07-01

    The Lower Albian in the south part of Santos Basin is composed mainly of oolitic calcarenites and calcilutites organized in shoaling upward cycles. The calcarenites from the top of the sequence constitute a package of reservoir zones and sub-zones with regional distribution along which are located mature, producing and development phase oil fields. In this work the main factors with major impact in reserves estimation are interpreted and quantified in a probabilistic approach giving support for the development plan phase of a field of the carbonatic trend. The regional stratigraphic and structural interpretations provided information about extension, external geometry, and continuity of the reservoir zones for reserves risk computation. The porosity probability density functions were defined according to stratigraphic position, seismic reflection pattern of calcarenites and also information from the discovery and the appraisal wells. The Decision Tree methodology with Monte Carlo Simulation was used to better understand the impact of geological uncertainties in reserves computation and also as a first step for risk management. The Monte Carlo simulation allows the Multivariate Sensibility and Scenario Analysis, Probabilistic Technical and Economic Evaluation and Optimal Portfolio Stochastic Simulation. (author)

  6. Assessing Reservoir Depositional Environments to Develop and Quantify Improvements in CO2 Storage Efficiency. A Reservoir Simulation Approach

    Okwen, Roland [University of Illinois, Champaign, IL (United States); Frailey, Scott [University of Illinois, Champaign, IL (United States); Leetaru, Hannes [University of Illinois, Champaign, IL (United States); Moulton, Sandy [Illinois State Geological Survey, Champaign, IL (United States)

    2014-09-30

    The storage potential and fluid movement within formations are dependent on the unique hydraulic characteristics of their respective depositional environments. Storage efficiency (E) quantifies the potential for storage in a geologic depositional environment and is used to assess basinal or regional CO2 storage resources. Current estimates of storage resources are calculated using common E ranges by lithology and not by depositional environment. The objectives of this project are to quantify E ranges and identify E enhancement strategies for different depositional environments via reservoir simulation studies. The depositional environments considered include deltaic, shelf clastic, shelf carbonate, fluvial deltaic, strandplain, reef, fluvial and alluvial, and turbidite. Strategies considered for enhancing E include CO2 injection via vertical, horizontal, and deviated wells, selective completions, water production, and multi-well injection. Conceptual geologic and geocellular models of the depositional environments were developed based on data from Illinois Basin oil fields and gas storage sites. The geologic and geocellular models were generalized for use in other US sedimentary basins. An important aspect of this work is the development of conceptual geologic and geocellular models that reflect the uniqueness of each depositional environment. Different injection well completions methods were simulated to investigate methods of enhancing E in the presence of geologic heterogeneity specific to a depositional environment. Modeling scenarios included horizontal wells (length, orientation, and inclination), selective and dynamic completions, water production, and multiwell injection. A Geologic Storage Efficiency Calculator (GSECalc) was developed to calculate E from reservoir simulation output. Estimated E values were normalized to diminish their dependency on fluid relative permeability. Classifying depositional environments according to

  7. Water in chalk reservoirs: 'friend or foe?'

    Hjuler, Morten Leth

    2004-01-01

    Most of the petroleum fields in the Norwegian sector of the North Sea are sandstone reservoirs; the oil and gas are trapped in different species of sandstone. But the Ekofisk Field is a chalk reservoir, which really challenges the operator companies. When oil is produced from chalk reservoirs, water usually gets in and the reservoir subsides. The subsidence may be expensive for the oil companies or be used to advantage by increasing the recovery rate. Since 60 per cent of the world's petroleum reserves are located in carbonate reservoirs, it is important to understand what happens as oil and gas are pumped out. Comprehensive studies at the Department of Petroleum Technology and Applied Geophysics at Stavanger University College in Norway show that the mechanical properties of chalk are considerably altered when the pores in the rock become saturated with oil/gas or water under different stress conditions. The processes are extremely complex. The article also maintains that the effects of injecting carbon dioxide from gas power plants into petroleum reservoirs should be carefully studied before this is done extensively

  8. Refined reservoir description to maximize oil recovery

    Flewitt, W.E.

    1975-01-01

    To assure maximized oil recovery from older pools, reservoir description has been advanced by fully integrating original open-hole logs and the recently introduced interpretive techniques made available through cased-hole wireline saturation logs. A refined reservoir description utilizing normalized original wireline porosity logs has been completed in the Judy Creek Beaverhill Lake ''A'' Pool, a reefal carbonate pool with current potential productivity of 100,000 BOPD and 188 active wells. Continuous porosity was documented within a reef rim and cap while discontinuous porous lenses characterized an interior lagoon. With the use of pulsed neutron logs and production data a separate water front and pressure response was recognized within discrete environmental units. The refined reservoir description aided in reservoir simulation model studies and quantifying pool performance. A pattern water flood has now replaced the original peripheral bottom water drive to maximize oil recovery

  9. Fundamental Understanding of Methane-Carbon Dioxide-Water (CH4-CO2-H2O) Interactions in Shale Nanopores under Reservoir Conditions.

    Wang, Yifeng [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-02-01

    Shale is characterized by the predominant presence of nanometer-scale (1-100 nm) pores. The behavior of fluids in those pores directly controls shale gas storage and release in shale matrix and ultimately the wellbore production in unconventional reservoirs. Recently, it has been recognized that a fluid confined in nanopores can behave dramatically differently from the corresponding bulk phase due to nanopore confinement (Wang, 2014). CO2 and H2O, either preexisting or introduced, are two major components that coexist with shale gas (predominately CH4) during hydrofracturing and gas extraction. Note that liquid or supercritical CO2 has been suggested as an alternative fluid for subsurface fracturing such that CO2 enhanced gas recovery can also serve as a CO2 sequestration process. Limited data indicate that CO2 may preferentially adsorb in nanopores (particularly those in kerogen) and therefore displace CH4 in shale. Similarly, the presence of water moisture seems able to displace or trap CH4 in shale matrix. Therefore, fundamental understanding of CH4-CO2-H2O behavior and their interactions in shale nanopores is of great importance for gas production and the related CO2 sequestration. This project focuses on the systematic study of CH4-CO2-H2O interactions in shale nanopores under high-pressure and high temperature reservoir conditions. The proposed work will help to develop new stimulation strategies to enable efficient resource recovery from fewer and less environmentally impactful wells.

  10. Fundamental Understanding of Methane-Carbon Dioxide-Water (CH4-CO2-H2O) Interactions in Shale Nanopores under Reservoir Conditions: Quarterly Report.

    Wang, Yifeng [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-11-01

    Shale is characterized by the predominant presence of nanometer-scale (1-100 nm) pores. The behavior of fluids in those pores directly controls shale gas storage and release in shale matrix and ultimately the wellbore production in unconventional reservoirs. Recently, it has been recognized that a fluid confined in nanopores can behave dramatically differently from the corresponding bulk phase due to nanopore confinement (Wang, 2014). CO2 and H2O, either preexisting or introduced, are two major components that coexist with shale gas (predominately CH4) during hydrofracturing and gas extraction. Note that liquid or supercritical CO2 has been suggested as an alternative fluid for subsurface fracturing such that CO2 enhanced gas recovery can also serve as a CO2 sequestration process. Limited data indicate that CO2 may preferentially adsorb in nanopores (particularly those in kerogen) and therefore displace CH4 in shale. Similarly, the presence of water moisture seems able to displace or trap CH4 in shale matrix. Therefore, fundamental understanding of CH4-CO2-H2O behavior and their interactions in shale nanopores is of great importance for gas production and the related CO2 sequestration. This project focuses on the systematic study of CH4-CO2-H2O interactions in shale nanopores under high-pressure and high temperature reservoir conditions. The proposed work will help to develop new stimulation strategies to enable efficient resource recovery from fewer and less environmentally impactful wells.

  11. Geologic assessment of undiscovered oil and gas resources in Aptian carbonates, onshore northern Gulf of Mexico Basin, United States

    Hackley, Paul C.; Karlsen, Alexander W.

    2014-01-01

    Carbonate lithofacies of the Lower Cretaceous Sligo Formation and James Limestone were regionally evaluated using established U.S. Geological Survey (USGS) assessment methodology for undiscovered conventional hydrocarbon resources. The assessed area is within the Upper Jurassic–Cretaceous–Tertiary Composite total petroleum system, which was defined for the assessment. Hydrocarbons reservoired in carbonate platform Sligo-James oil and gas accumulations are interpreted to originate primarily from the Jurassic Smackover Formation. Emplacement of hydrocarbons occurred via vertical migration along fault systems; long-range lateral migration also may have occurred in some locations. Primary reservoir facies include porous patch reefs developed over paleostructural salt highs, carbonate shoals, and stacked linear reefs at the carbonate shelf margin. Hydrocarbon traps dominantly are combination structural-stratigraphic. Sealing lithologies include micrite, calcareous shale, and argillaceous lime mudstone. A geologic model, supported by discovery history analysis of petroleum geology data, was used to define a single regional assessment unit (AU) for conventional reservoirs in carbonate facies of the Sligo Formation and James Limestone. The AU is formally entitled Sligo-James Carbonate Platform Oil and Gas (50490121). A fully risked mean undiscovered technically recoverable resource in the AU of 50 million barrels of oil (MMBO), 791 billion cubic feet of natural gas (BCFG), and 26 million barrels of natural gas liquids was estimated. Substantial new development through horizontal drilling has occurred since the time of this assessment (2010), resulting in cumulative production of >200 BCFG and >1 MMBO.

  12. Effects of fuel and forest conservation on future levels of atmospheric carbon dioxide.

    Walker, J C; Kasting, J F

    1992-01-01

    We develop a numerical simulation of the global biogeochemical cycles of carbon that works over time scales extending from years to millions of years. The ocean is represented by warm and cold shallow water reservoirs, a thermocline reservoir, and deep Atlantic, Indian, and Pacific reservoirs. The atmosphere is characterized by a single carbon reservoir and the global biota by a single biomass reservoir. The simulation includes the rock cycle, distinguishing between shelf carbonate and pelagic carbonate precipitation, with distinct lysocline depths in the three deep ocean reservoirs. Dissolution of pelagic carbonates in response to decrease in lysocline depth is included. The simulation is tuned to reproduce the observed radiocarbon record resulting from atomic weapon testing. It is tuned also to reproduce the distribution of dissolved phosphate and total dissolved carbon between the ocean reservoirs as well as the carbon isotope ratios for both 13C and 14C in ocean and atmosphere. The simulation reproduces reasonably well the historical record of carbon dioxide partial pressure as well as the atmospheric isotope ratios for 13C and 14C over the last 200 yr as these have changed in response to fossil fuel burning and land use changes, principally forest clearance. The agreements between observation and calculation involves the assumption of a carbon dioxide fertilization effect in which the rate of production of biomass increases with increasing carbon dioxide partial pressure. At present the fertilization effect of increased carbon dioxide outweighs the effects of forest clearance, so the biota comprises an overall sink of atmospheric carbon dioxide sufficiently large to bring the budget approximately into balance. This simulation is used to examine the future evolution of carbon dioxide and its sensitivity to assumptions about the rate of fossil fuel burning and of forest clearance. Over times extending up to thousands of years, the results are insensitive to the

  13. Fortescue reservoir development and reservoir studies

    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.

  14. Transport of reservoir fines

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

    Modeling transport of reservoir fines is of great importance for evaluating the damage of production wells and infectivity decline. The conventional methodology accounts for neither the formation heterogeneity around the wells nor the reservoir fines’ heterogeneity. We have developed an integral...... dispersion equation in modeling the transport and the deposition of reservoir fines. It successfully predicts the unsymmetrical concentration profiles and the hyperexponential deposition in experiments....

  15. Reservoir Engineering Management Program

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

    1977-12-14

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

  16. Downslope flow across the Ross Sea shelf break (Antarctica)

    Bergamasco, A.; Budillon, G.; Carniel, S.; Defendi, V.; Meloni, R.; Paschini, E.; Sclavo, M.; Spezie, G.

    2003-12-01

    crucial role in the formation of oceanic deep water responsible for ocean/continental shelf exchange of organic carbon, suspended material and dissolved gases around Antarctica. In this context, this work presents the analysis of the 1997, 2001 and 2003 high-resolution surveys carried out in the western Ross Sea near Cape Adare, where the HSSW flows down the continental slope. The second study area was investigated during the 1998 survey of the Italian National Programme for Antarctic Research of the CLIMA Project, in order to follow the ISW overflow path at the shelf break in the central Ross Sea. A 3D primitive equation model was also implemented as a first step in the construction of a high-resolution process study model to explore the dynamical constraints involved in the downslope motion.

  17. Impacts of a weather event on shelf circulation and CO2 and O2 dynamics on the Louisiana shelf during summer 2009

    Huang, W.-J.; Cai, W.-J.; Wang, Y.; Hopkinson, C. S.

    2013-12-01

    While much is known about the physics of coastal currents, much less is known about the biogeochemical effects of surface currents on shelf carbon dioxide (CO2) and oxygen distribution and dynamics. The Mississippi and Atchafalaya River plume is usually observed along the Louisiana shelf with easterly winds. Such a typical pattern was observed in August 2007, i.e. a plume of low salinity and low partial pressure of CO2 (pCO2), indicating high biological production on the inner shelf; and higher salinity and pCO2 on the outer shelf. This high biological production induced by riverine nitrogen flux thus provided major organic matter sources for the shelf-wide hypoxia (dissolved oxygen [DO] hypoxic area. Furthermore, DIC concentration in bottom waters was higher than those predicted by the Redfield ratio, most likely because of much rapid O2 compensation than CO2 loss during air-sea exchange. Numerical models indicate such relocation of plume was mostly affected by the shelf circulation dominated by southerly and southwesterly winds. Consequently, we conclude that wind-forcing and shelf circulation are critical factors that influence the plume trajectories and the associated biogeochemical properties in coastal waters.

  18. Water masses of Visakhapatnam shelf

    RamaRaju, V.S.; Sarma, V.V.; Rao, B.P.; Rao, V.S.

    The T-S relationships of shelf waters off Visakhapatnam in the Bay of Bengal are studied for the different seasons with the data collected during February 1979 to January 1981. The T-S relationships indicate distinct characteristics of the water...

  19. Highstand shelf fans: The role of buoyancy reversal in the deposition of a new type of shelf sand body

    Steel, Elisabeth; Simms, Alexander R.; Warrick, Jonathan; Yokoyama, Yusuke

    2016-01-01

    Although sea-level highstands are typically associated with sediment-starved continental shelves, high sea level does not hinder major river floods. Turbidity currents generated by plunging of sediment-laden rivers at the fluvial-marine interface, known as hyperpycnal flows, allow for cross-shelf transport of suspended sand beyond the coastline. Hyperpycnal flows in southern California have deposited six subaqueous fans on the shelf of the northern Santa Barbara Channel in the Holocene. Using eight cores and nine grab samples, we describe the deposits, age, and stratigraphic architecture of two fans in the Santa Barbara Channel. Fan lobes have up to 3 m of relief and are composed of multiple hyperpycnite beds ∼5 cm to 40 cm thick. Deposit architecture and geometry suggest the hyperpycnal flows became positively buoyant and lifted off the seabed, resulting in well-sorted, structureless, elongate sand lobes. Contrary to conventional sequence stratigraphic models, the presence of these features on the continental shelf suggests that active-margin shelves may locally develop high-quality reservoir sand bodies during sea-level highstands, and that such shelves need not be solely the site of sediment bypass. These deposits may provide a Quaternary analogue to many well-sorted sand bodies in the rock record that are interpreted as turbidites but lack typical Bouma-type features.

  20. Phosphatised limestones and associated sediments from the western continental shelf of India

    Rao, V.P.; Natarajan, R.; Parthiban, G.; Mascarenhas, A.

    Quaternary carbonate sediments: Rao, Ch.M., Paropkari~ A.L., Mascarenhas, A. and Murty, carbonate sediments and reefs, Yucatan shelf, Mexico. Am. P.S.N., 1987. Distribution of phosphorus and phosphatisa- Assoc. Pet. Geol. Mem., 11: 1-128. tion along...

  1. Coordination: southeast continental shelf studies. Progress report

    Menzel, D.W.

    1981-02-01

    The objectives are to identify important physical, chemical and biological processes which affect the transfer of materials on the southeast continental shelf, determine important parameters which govern observed temporal and spatial varibility on the continental shelf, determine the extent and modes of coupling between events at the shelf break and nearshore, and determine physical, chemical and biological exchange rates on the inner shelf. Progress in meeting these research objectives is presented. (ACR)

  2. Sediment management for reservoir

    Rahman, A.

    2005-01-01

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

  3. Optimising reservoir operation

    Ngo, Long le

    Anvendelse af optimeringsteknik til drift af reservoirer er blevet et væsentligt element i vandressource-planlægning og -forvaltning. Traditionelt har reservoirer været styret af heuristiske procedurer for udtag af vand, suppleret i en vis udstrækning af subjektive beslutninger. Udnyttelse af...... reservoirer involverer en lang række interessenter med meget forskellige formål (f.eks. kunstig vanding, vandkraft, vandforsyning mv.), og optimeringsteknik kan langt bedre lede frem til afbalancerede løsninger af de ofte modstridende interesser. Afhandlingen foreslår en række tiltag, hvormed traditionelle...

  4. Studies of fracture network geometry of reservoir outcrop analogues from terrestrial lidar data: attempts to quantify spatial variations of fracture characteristics

    Vsemirnova, E. A.; Jones, R. R.; McCaffrey, K. J. W.

    2012-04-01

    We describe studies analysing terrestrial lidar datasets of fracture systems from a range of reservoir analogues in clastic and carbonate lithologies that represent geological analogues of offshore hydrocarbon reservoirs for the UK continental shelf. As fracture networks (observed here from centimetre to kilometre scale) can significantly affect the permeability of a fractured reservoir, the definition of fracture network geometry at various scales has become an important goal of structural analysis. The main aim of the study has been to extend the investigation of fracture networks in order to quantify spatial variations in fracture parameters in a variety of lithologies. The datasets were pre-processed using RiSCAN PRO software, and then re-sampled and filtered to derive characteristics which are traditionally measured from outcrops, including size distributions, fracture spacing and clustering statistics. This type of analysis can significantly reduce the uncertainty associated with some field fracture network measurements. The digitised fracture networks datasets are then used to investigate various aspects of spatial heterogeneity. A series of fracture maps (joints and faults) were generated at different scales, and fracture trends were studied to test scale dependency of fracture orientations. Multiscale trend analysis was then applied to describe the trend structure of the fracture networks.

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

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

    2013-12-01

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

  6. Significance of peat on the western continental shelf of India

    Mascarenhas, A.

    24 and 31 meters. The cores were subsampled depending upon the lithology. A core off Karwar was chosen for geochemical analyses. Calcium carbonate was determined using a 'KarbonatBombe' (Muller and Gastner, 1971). Organic carbon and sulfur were... the present sea level; it is found up to 27 km from the coast. The resulls suggest that peat on the shelf occurs as layers of restricted thickness (2 to 30 em) with a limited lateral distribution and hence appear to be impersistent layers. A strong hydrogen...

  7. Greenhouse gas emissions from hydroelectric reservoirs

    Rosa, L.P.; Schaeffer, R.

    1994-01-01

    In a recent paper, Rudd et al. have suggested that, per unit of electrical energy produced, greenhouse-gas emissions from some hydroelectric reservoirs in northern Canada may be comparable to emissions from fossil-fuelled power plants. The purpose of this comment is to elaborate these issues further so as to understand the potential contribution of hydroelectric reservoirs to the greenhouse effect. More than focusing on the total budget of carbon emissions (be they in the form of CH 4 or be they in the form of CO 2 ), this requires an evaluation of the accumulated greenhouse effect of gas emissions from hydroelectric reservoirs and fossil-fuelled power plants. Two issues will be considered: (a) global warming potential (GWP) for CH 4 ; and (b) how greenhouse-gas emissions from hydroelectric power plants stand against emissions from fossil-fuelled power plants with respect to global warming

  8. Endmembers of Ice Shelf Melt

    Boghosian, A.; Child, S. F.; Kingslake, J.; Tedesco, M.; Bell, R. E.; Alexandrov, O.; McMichael, S.

    2017-12-01

    Studies of surface melt on ice shelves have defined a spectrum of meltwater behavior. On one end the storage of meltwater in persistent surface ponds can trigger ice shelf collapse as in the 2002 event leading to the disintegration of the Larsen B Ice Shelf. On the other, meltwater export by rivers can stabilize an ice shelf as was recently shown on the Nansen Ice Shelf. We explore this dichotomy by quantifying the partitioning between stored and transported water on two glaciers adjacent to floating ice shelves, Nimrod (Antarctica) and Peterman (Greenland). We analyze optical satellite imagery (LANDSAT, WorldView), airborne imagery (Operation IceBridge, Trimetrogon Aerial Phototography), satellite radar (Sentinel-1), and digital elevation models (DEMs) to categorize surface meltwater fate and map the evolution of ice shelf hydrology and topographic features through time. On the floating Peterman Glacier tongue a sizable river exports water to the ocean. The surface hydrology of Nimrod Glacier, geometrically similar to Peterman but with ten times shallower surface slope, is dominated by storage in surface lakes. In contrast, the Nansen has the same surface slope as Nimrod but transports water through surface rivers. Slope alone is not the sole control on ice shelf hydrology. It is essential to track the storage and transport volumes for each of these systems. To estimate water storage and transport we analyze high resolution (40 cm - 2 m) modern and historical DEMs. We produce historical (1957 onwards) DEMs with structure-from-motion photogrammetry. The DEMs are used to constrain water storage potential estimates of observed basins and water routing/transport potential. We quantify the total volume of water stored seasonally and interannually. We use the normalize difference water index to map meltwater extent, and estimate lake water depth from optical data. We also consider the role of stored water in subsurface aquifers in recharging surface water after

  9. Reservoir characterization of Pennsylvanian sandstone reservoirs. Final report

    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.

  10. Improved characterization of reservoir behavior by integration of reservoir performances data and rock type distributions

    Davies, D.K.; Vessell, R.K. [David K. Davies & Associates, Kingwood, TX (United States); Doublet, L.E. [Texas A& M Univ., College Station, TX (United States)] [and others

    1997-08-01

    An integrated geological/petrophysical and reservoir engineering study was performed for a large, mature waterflood project (>250 wells, {approximately}80% water cut) at the North Robertson (Clear Fork) Unit, Gaines County, Texas. The primary goal of the study was to develop an integrated reservoir description for {open_quotes}targeted{close_quotes} (economic) 10-acre (4-hectare) infill drilling and future recovery operations in a low permeability, carbonate (dolomite) reservoir. Integration of the results from geological/petrophysical studies and reservoir performance analyses provide a rapid and effective method for developing a comprehensive reservoir description. This reservoir description can be used for reservoir flow simulation, performance prediction, infill targeting, waterflood management, and for optimizing well developments (patterns, completions, and stimulations). The following analyses were performed as part of this study: (1) Geological/petrophysical analyses: (core and well log data) - {open_quotes}Rock typing{close_quotes} based on qualitative and quantitative visualization of pore-scale features. Reservoir layering based on {open_quotes}rock typing {close_quotes} and hydraulic flow units. Development of a {open_quotes}core-log{close_quotes} model to estimate permeability using porosity and other properties derived from well logs. The core-log model is based on {open_quotes}rock types.{close_quotes} (2) Engineering analyses: (production and injection history, well tests) Material balance decline type curve analyses to estimate total reservoir volume, formation flow characteristics (flow capacity, skin factor, and fracture half-length), and indications of well/boundary interference. Estimated ultimate recovery analyses to yield movable oil (or injectable water) volumes, as well as indications of well and boundary interference.

  11. Characterization of oil and gas reservoir heterogeneity

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

    1992-10-01

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

  12. Two-point versus multiple-point geostatistics: the ability of geostatistical methods to capture complex geobodies and their facies associations—an application to a channelized carbonate reservoir, southwest Iran

    Hashemi, Seyyedhossein; Javaherian, Abdolrahim; Ataee-pour, Majid; Khoshdel, Hossein

    2014-01-01

    Facies models try to explain facies architectures which have a primary control on the subsurface heterogeneities and the fluid flow characteristics of a given reservoir. In the process of facies modeling, geostatistical methods are implemented to integrate different sources of data into a consistent model. The facies models should describe facies interactions; the shape and geometry of the geobodies as they occur in reality. Two distinct categories of geostatistical techniques are two-point and multiple-point (geo) statistics (MPS). In this study, both of the aforementioned categories were applied to generate facies models. A sequential indicator simulation (SIS) and a truncated Gaussian simulation (TGS) represented two-point geostatistical methods, and a single normal equation simulation (SNESIM) selected as an MPS simulation representative. The dataset from an extremely channelized carbonate reservoir located in southwest Iran was applied to these algorithms to analyze their performance in reproducing complex curvilinear geobodies. The SNESIM algorithm needs consistent training images (TI) in which all possible facies architectures that are present in the area are included. The TI model was founded on the data acquired from modern occurrences. These analogies delivered vital information about the possible channel geometries and facies classes that are typically present in those similar environments. The MPS results were conditioned to both soft and hard data. Soft facies probabilities were acquired from a neural network workflow. In this workflow, seismic-derived attributes were implemented as the input data. Furthermore, MPS realizations were conditioned to hard data to guarantee the exact positioning and continuity of the channel bodies. A geobody extraction workflow was implemented to extract the most certain parts of the channel bodies from the seismic data. These extracted parts of the channel bodies were applied to the simulation workflow as hard data

  13. Modelling shelf-ocean exchange and its biogeochemical consequences in coastal upwelling systems

    Muchamad, Al Azhar

    margin bathymetry, and 3) what processes determine the observed variability of total organic carbon (TOC) content in shelf sediments underlying the upwelling system, with implications for the formation of petroleum source rocks. Here, a numerical ocean modeling approach is used in this thesis to explore...... processes and the development of anoxia/euxinia under the present day or past geological conditions. Thirdly and last, processes controlling distribution of total organic carbon (TOC) content in sediments across the continental margin is evaluated by application of the model to the Benguela upwelling system....... In the model, biological primary production and shelf bottom-water anoxia result in enhanced sedimentary TOC concentrations on the mid shelf and upper slope. The simulated TOCs implicate that bottom lateral transport only has a significant effect on increasing the deposition of the organic carbon on the mid...

  14. Changes of deep Pacific overturning circulation and carbonate chemistry during middle Miocene East Antarctic ice sheet expansion

    Ma, Xiaolin; Tian, Jun; Ma, Wentao; Li, Ke; Yu, Jimin

    2018-02-01

    East Antarctic ice sheet expansion (EAIE) at ∼13.9 Ma in the middle Miocene represents a major climatic event during the long-term Cenozoic cooling, but ocean circulation and carbon cycle changes during this event remain unclear. Here, we present new fish teeth isotope (εNd) and benthic foraminiferal B/Ca records from the South China Sea (SCS), newly integrated meridional Pacific benthic foraminiferal δ18O and δ13C records and simulated results from a biogeochemical box model to explore the responses of deep Pacific Ocean circulation and carbon cycle across EAIE. The εNd and meridional benthic δ13C records reveal a more isolated Pacific Deep Water (PDW) and a sluggish Pacific meridional overturning circulation during the post-EAIE with respect to the pre-EAIE owing to weakened southern-sourced deep water formation. The deep-water [CO23-] and calcium carbonate mass accumulation rate in the SCS display markedly similar increases followed by recoveries to the pre-EAIE level during EAIE, which were probably caused by a shelf-basin shift of CaCO3 deposition and strengthened weathering due to a sea level fall within EAIE. The model results show that the ∼1‰ positive δ13C excursion during EAIE could be attributed to increased weathering of high-δ13C shelf carbonates and a terrestrial carbon reservoir expansion. The drawdown of atmospheric CO2 over the middle Miocene were probably caused by combined effects of increased shelf carbonate weathering, expanded land biosphere carbon storage and a sluggish deep Pacific meridional overturning circulation.

  15. Seabed geology of the Canadian eastern continental shelf

    Piper, David J. W.

    1991-08-01

    The physiography of the continental shelf off eastern Canada is irregular, developed by glacial erosion of a previously fluvially-dominated landscape. Northern shelves are deeper than southern shelves. Most surficial sediments on the shelf are relict or palimpsest. The principal modern source of sediment to the northern shelves is ice rafting and iceberg scour reworking of Quaternary sediments. Southern shelves receive sediment through erosion of Quaternary sediments; only small amounts of fine-grained sediment derived from coastal erosion and rivers escape from the coastal zone. Regional maps of sediment texture, carbonate content and heavy mineralogy consequently show differences between the northern and southern shelves. Large areas of the shelf show little net deposition. On the northern shelves, there is a surface veneer up to 0.5 m thick derived from ice rafting and iceberg turbation of underlying Quaternary sediment, modified by south-flowing currents [ WOODWORTH-LYNASet al. (this issue) Continental Shelf Research, 11, 939-961]. The overall effects of former iceberg turbation may extend to a depth of 10 m sub-bottom. On the southern shelves, bioturbation and perhaps storm-related currents rework exposed Quaternary sediments more slowly. Muds accumulate in deep basins on the shelves at rates of about 0.5 m per 1000 years; this accumulation is probably episodic and related to major storms reworking sediment from the surface sediment veneer in shallower areas of little net deposition. In water depths less than 110 m sand and gravel have formed as a result of reworking in the coastal zone during the post-glacial transgression. Over large areas of Georges Bank, the eastern Scotian Shelf and the Grand Banks of Newfoundland, such sands are mobilized during storms to form a wide suite of bedforms [ AMOS and JUDGE (this issue) Continental Shelf Research, 11, 1037-1068]. Elsewhere, particularly in deeper water, sandy surfaces appear moribund or inactive and large

  16. A Poromechanical Model for Coal Seams Injected with Carbon Dioxide: From an Isotherm of Adsorption to a Swelling of the Reservoir Un modéle poromécanique pour l’injection de dioxyde de carbone dans des veines de charbon : d’une isotherme d’adsorption à un gonflement du réservoir

    Nikoosokhan S.

    2012-11-01

    Full Text Available Injecting carbon dioxide into deep unminable coal seams can enhance the amount of methane recovered from the seam. This process is known as CO2-Enhanced Coal Bed Methane production (CO2-ECBM. The seam is a porous medium whose porous system is made of cleats (small natural fractures and of coal pores (whose radius can be as small as a few angström. During the injection process, the molecules of CO2 get adsorbed in the coal pores. Such an adsorption makes the coal swell, which, in the confined conditions that prevail underground, induces a closure of the cleat system of the coal bed reservoir and a loss of injectivity. In this work, we develop a poromechanical model which, starting from the knowledge of an adsorption isotherm and combined with reservoir simulations, enables to estimate the variations of injectivity of the coal bed reservoir over time during the process of injection. The model for the coal bed reservoir is based on poromechanical equations that explicitly take into account the effect of adsorption on the mechanical behavior of a microporous medium. We consider the coal bed reservoir as a dual porosity (cleats and coal porosity medium, for which we derive a set of linear constitutive equations. The model requires as an input the adsorption isotherm on coal of the fluid considered. Reversely, the model provides a way to upscale an adsorption isotherm into a meaningful swelling of the coal bed reservoir at the macroscopic scale. The parameters of the model are calibrated on data on coal samples available in the literature. Reservoir simulations of an injection of carbon dioxide in a coal seam are performed with an in-house finite volume and element code. The variations of injection rate over time during the process of injection are obtained from the simulations. The effect of the compressibility of the coal matrix on those variations is discussed. L’injection de dioxyde de carbone dans des veines de charbon profondes peut augmenter

  17. How fast is the Patagonian shelf-break acidifying?

    Orselli, Iole B. M.; Kerr, Rodrigo; Ito, Rosane G.; Tavano, Virginia M.; Mendes, Carlos Rafael B.; Garcia, Carlos A. E.

    2018-02-01

    Anthropogenic carbon (Cant) concentration is determined according to the TrOCA method, from carbonate system data and hydrographic parameters collected during two consecutive spring cruises (2007 and 2008) in the Argentinean Patagonian shelf-break zone between 36°S and 50°S. Cant has intruded the water column until intermediate depths, with no Cant below 1000 m, in the deeper waters (i.e., North Atlantic Deep Water and Antarctic Bottom Water) of the Northern sector of the study area (i.e., North of 38°S). The higher Cant concentration is observed in Subantarctic Shelf Water in the Southern region, whereas in the Northern sector both Tropical Water and South Atlantic Central Water are equally affected by Cant intrusion. The Antarctic Intermediate Water represents the depth-limit achieved by Cant penetration, reinforcing the role that this water mass plays as an important vehicle to transport Cant to the oceans interior. The estimated Cant average (± method precision) is 46.6 ± 5.3 μmol kg- 1, considering the full depth of the water column. The ocean acidification state (ΔpH) shows an average (± standard deviation) of - 0.11 ± 0.05, thus, indicating an annual pH reduction of - 0.0010 yr- 1 since the Industrial Revolution (c.a. 1750). The degree of aragonite saturation is lowered towards undersaturation levels of calcite. The Patagonian shelf and shelf-break zones-a strong CO2 sink region in the global ocean-are likely a key area for Cant intrusion in the southwestern South Atlantic Ocean.

  18. Chronicling ice shelf history in the sediments left behind

    Rosenheim, B. E.; Subt, C.; Shevenell, A.; Guitard, M.; Vadman, K. J.; DeCesare, M.; Wellner, J. S.; Bart, P. J.; Lee, J. I.; Domack, E. W.; Yoo, K. C.; Hayes, J. M.

    2017-12-01

    Collapsing and retreating ice shelves leave unmistakable sediment sequences on the Antarctic margin. These sequences tell unequivocal stories of collapse or retreat through a typical progression of sub-ice shelf diamicton (marking the past positions of grounding lines), sequentially overlain by a granulated facies from beneath the ice shelf, ice rafted debris from the calving line, and finally open marine sediment. The timelines to these stories, however, are troublesome. Difficulties in chronicling these stories recorded in sediment have betrayed their importance to our understanding of a warming world in many cases. The difficulties involve the concerted lack of preservation/production of calcium carbonate tests from the water column above and admixture of relict organic material from older sources of carbon. Here, we summarize our advances in the last decade of overcoming difficulties associated with the paucity of carbonate and creating chronologies of ice shelf retreat into the deglacial history of Antarctica by exploiting the range of thermochemical stability in organic matter (Ramped PyrOx) from these sediment sequences. We describe our success in comparing Ramped PyrOx 14C dates with foraminiferal dates, the relationship between sediment facies and radiocarbon age spectrum, and our ability to push limits of dating sediments deposited underneath ice shelves. With attention to the caveats of recent dating developments, we summarize expectations that geologist should have when coring the Antarctic margins to discern deglacial history. Perhaps most important among these expectations is the ability to design coring expeditions without regard to our ability to date calcium carbonate microfossils within the cores, in essence removing suspense of knowing whether cores taken from crucial paleo ice channels and other bathymetric features will ultimately yield a robust chronology for its sedimentary sequence.

  19. The weeding handbook a shelf-by-shelf guide

    Vnuk, Rebecca

    2015-01-01

    "No! We can't rid of that!" Vnuk, author of the popular "Weeding Tips" column on Booklist Online, is here to show you that yes, you can. A library is an ever-changing organism; when done the right way, weeding helps a library thrive by focusing its resources on those parts of the collection that are the most useful to its users. Her handbook takes the guesswork out of this delicate but necessary process, giving public and school library staff the knowledge and the confidence to effectively weed any collection, of any size. Going through the proverbial stacks shelf by shelf, Vnuk: Explains why weeding is important for a healthy library, demonstrating that a vibrant collection leads to robust circulation, which in turn affects library budgets Walks readers through a library's shelves by Dewey area, with recommended weeding criteria and call-outs in each area for the different considerations of large collections and smaller collections Features a chapter addressing reference, media, magazines and newspapers, e-b...

  20. Geothermal reservoir engineering

    Grant, Malcolm Alister

    2011-01-01

    As nations alike struggle to diversify and secure their power portfolios, geothermal energy, the essentially limitless heat emanating from the earth itself, is being harnessed at an unprecedented rate.  For the last 25 years, engineers around the world tasked with taming this raw power have used Geothermal Reservoir Engineering as both a training manual and a professional reference.  This long-awaited second edition of Geothermal Reservoir Engineering is a practical guide to the issues and tasks geothermal engineers encounter in the course of their daily jobs. The bo

  1. On the shelf life of pharmaceutical products.

    Capen, Robert; Christopher, David; Forenzo, Patrick; Ireland, Charles; Liu, Oscar; Lyapustina, Svetlana; O'Neill, John; Patterson, Nate; Quinlan, Michelle; Sandell, Dennis; Schwenke, James; Stroup, Walter; Tougas, Terrence

    2012-09-01

    This article proposes new terminology that distinguishes between different concepts involved in the discussion of the shelf life of pharmaceutical products. Such comprehensive and common language is currently lacking from various guidelines, which confuses implementation and impedes comparisons of different methodologies. The five new terms that are necessary for a coherent discussion of shelf life are: true shelf life, estimated shelf life, supported shelf life, maximum shelf life, and labeled shelf life. These concepts are already in use, but not named as such. The article discusses various levels of "product" on which different stakeholders tend to focus (e.g., a single-dosage unit, a batch, a production process, etc.). The article also highlights a key missing element in the discussion of shelf life-a Quality Statement, which defines the quality standard for all key stakeholders. Arguments are presented that for regulatory and statistical reasons the true product shelf life should be defined in terms of a suitably small quantile (e.g., fifth) of the distribution of batch shelf lives. The choice of quantile translates to an upper bound on the probability that a randomly selected batch will be nonconforming when tested at the storage time defined by the labeled shelf life. For this strategy, a random-batch model is required. This approach, unlike a fixed-batch model, allows estimation of both within- and between-batch variability, and allows inferences to be made about the entire production process. This work was conducted by the Stability Shelf Life Working Group of the Product Quality Research Institute.

  2. Swell propagation across a wide continental shelf

    Hendrickson, Eric J.

    1996-01-01

    The effects of wave refraction and damping on swell propagation across a wide continental shelf were examined with data from a transect of bottom pressure recorders extending from the beach to the shelf break near Duck, North Carolina. The observations generally show weak variations in swell energy across the shelf during benign conditions, in qualitative agreement with predictions of a spectral refraction model. Although the predicted ray trajectories are quite sensitive to the irregular she...

  3. Skeletal carbonate on the continental shelf: SEM evidence of early diagenetic alteration of the 1% of shells that persist for millennia in the mixed layer and thus enter the permanent record

    Kidwell, S. M.; Tomasovych, A.; Alexander, C. R., Jr.

    2016-02-01

    An extensive program of dating aragonitic bivalve shells from the mixed-layer of the southern California shelf using AMS-calibrated amino-acid racemization has revealed strongly right-skewed shell-age frequency distributions: the median age of shells (2-7 mm) is quite young, generally <100 y, but the distribution includes a long tail of old shells 2550 to 11,900 y (Tomasovych et al. 2014 Geology). Modeling indicates that shells experience a high initial disintegration rate λ1 ( decadal half-lives) but shift abruptly, within the first 500 y, to a 100-fold lower disintegration rate λ2 ( millennial half-lives) at sequestration rate τ (burial and/or diagenetic stabilization). Although this drop permits the accrual of a long tail of very old shells, <1% of shells survive the first phase. In the fossil record, proxy geochemical and ecological data are extracted from such survivors, and so understanding the mechanisms of shell persistence in the mixed layer is critical to confident paleoenvironmental inference. We have hypothesized that permanent diagenetic stabilization within the mixed layer, which Pb-210 shows is 4-17 cm thick on this shelf, may be necessary to ensure that shells do not revert to λ1 after temporary sequestration in pockets of favorable porewater. Our new SEM of shells of known, AMS-calibrated post-mortem age shows that macroscopic (10x) variation in shell color and luster is related to (1) loss of inter-crystallite organic matrix, probably by microbial maceration (chalky phase; within a few years post-mortem), (2) development of a surficial skim-coat of large, complexly interdigitating "jigsaw" crystallites, consistent with Ostwald ripening (shells re-acquire luster; patches develop within 10s y and coalesce over 100s to k y), and (3) development of a consistently fine-grained, apparently penetrative fabric, suggesting replacement of the original microstructure by a novel authigenic phase (gray stain; shells ≥ 5 ka). Electron back

  4. Whither the UK Continental Shelf?

    Kemp, A.G.

    1999-01-01

    The development of the oil and gas fields on the United Kingdom continental shelf has been carried out with remarkable success. However, low oil prices now threaten fresh investment and make it likely that both oil and gas output will start to fall in about 2001. The impact of a number of different price scenarios on further development is assessed. It is concluded that continuing technological improvements and the provision of adequate incentives by government should ensure a long productive future for the province. (UK)

  5. Nagylengyel: an interesting reservoir. [Yugoslovia

    Dedinszky, J

    1971-04-01

    The Nagylengyel oil field, discovered in 1951, has oil-producing formations mostly in the Upper-Triassic dolomites, in the Norian-Ractian transition formations, in the Upper-Cretaceous limestones and shales, and in the Miocene. The formation of the reservoir space occurred in many stages. A porous, cavernous fractured reservoir is developed in the Norian principal dolomite. A cavernous fractured reservoir exists in the Cretaceous limestone and in the Cretaceous shale and porous fractured reservoir is developed in the Miocene. The derivation of the model of the reservoir, and the conservative evaluation of the volume of the reservoir made it possible to use secondary recovery.

  6. Shelf life of electronic/electrical devices

    Polanco, S.; Behera, A.K.

    1993-01-01

    This paper discusses inconsistencies which exist between various industry practices regarding the determination of shelf life for electrical and electronic components. New methodologies developed to evaluate the shelf life of electrical and electronic components are described and numerous tests performed at Commonwealth Edison Company's Central Receiving Inspection and Testing (CRIT) Facility are presented. Based upon testing and analysis using the Arrhenius methodology and typical materials used in the manufacturing of electrical and electronic components, shelf life of these devices was determined to be indefinite. Various recommendations to achieve an indefinite. Various recommendations to achieve an indefinite shelf life are presented to ultimately reduce inventory and operating costs at nuclear power plants

  7. Parallel reservoir simulator computations

    Hemanth-Kumar, K.; Young, L.C.

    1995-01-01

    The adaptation of a reservoir simulator for parallel computations is described. The simulator was originally designed for vector processors. It performs approximately 99% of its calculations in vector/parallel mode and relative to scalar calculations it achieves speedups of 65 and 81 for black oil and EOS simulations, respectively on the CRAY C-90

  8. unconventional natural gas reservoirs

    Correa G, Tomas F; Osorio, Nelson; Restrepo R, Dora P

    2009-01-01

    This work is an exploration about different unconventional gas reservoirs worldwide: coal bed methane, tight gas, shale gas and gas hydrate? describing aspects such as definition, reserves, production methods, environmental issues and economics. The overview also mentioned preliminary studies about these sources in Colombia.

  9. Exploration and reservoir characterization; Technology Target Areas; TTA2 - Exploration and reservoir characterisation

    2008-07-01

    In future, research within exploration and reservoir characterization will play an even more important role for Norway since resources are decreasing and new challenges like deep sea, harsh environment and last but not least environmental issues have to be considered. There are two major fields which have to be addressed within exploration and reservoir characterization: First, replacement of reserves by new discoveries and ultimate field recoveries in mature basins at the Norwegian Continental shelf, e.g. at the Halten Terrace has to be addressed. A wealth of data exists in the more mature areas. Interdisciplinary integration is a key feature of reservoir characterization, where available data and specialist knowledge need to be combined into a consistent reservoir description. A systematic approach for handling both uncertainties in data sources and uncertainties in basic models is needed. Fast simulation techniques are necessary to generate models spanning the event space, covering both underground based and model-based uncertainties. Second, exploration in frontier areas like the Barents Sea region and the deeper Voering Basin has to be addressed. The scarcity of wells in these frontier areas leads to uncertainties in the geological understanding. Basin- and depositional modelling are essential for predicting where source rocks and reservoir rocks are deposited, and if, when and which hydrocarbons are generated and trapped. Predictive models and improved process understanding is therefore crucial to meet these issues. Especially the challenges related to the salt deposits e.g. sub-salt/sub-basalt reservoir definitions in the Nordkapp Basin demands up-front research and technology developments. TTA2 stresses the need to focus on the development of new talents. We also see a strong need to push cooperation as far as possible in the present competitive environment. Projects that may require a substantial financial commitment have been identified. The following

  10. Adsorption of hydrocarbons in chalk reservoirs

    Madsen, L.

    1996-12-31

    The present work is a study on the wettability of hydrocarbon bearing chalk reservoirs. Wettability is a major factor that influences flow, location and distribution of oil and water in the reservoir. The wettability of the hydrocarbon reservoirs depends on how and to what extent the organic compounds are adsorbed onto the surfaces of calcite, quartz and clay. Organic compounds such as carboxylic acids are found in formation waters from various hydrocarbon reservoirs and in crude oils. In the present investigation the wetting behaviour of chalk is studied by the adsorption of the carboxylic acids onto synthetic calcite, kaolinite, quartz, {alpha}-alumina, and chalk dispersed in an aqueous phase and an organic phase. In the aqueous phase the results clearly demonstrate the differences between the adsorption behaviour of benzoic acid and hexanoic acid onto the surfaces of oxide minerals and carbonates. With NaCl concentration of 0.1 M and with pH {approx_equal} 6 the maximum adsorption of benzoic acid decreases in the order: quartz, {alpha}-alumina, kaolinite. For synthetic calcite and chalk no detectable adsorption was obtaind. In the organic phase the order is reversed. The maximum adsorption of benzoic acid onto the different surfaces decreases in the order: synthetic calcite, chalk, kaolinite and quartz. Also a marked difference in adsorption behaviour between probes with different functional groups onto synthetic calcite from organic phase is observed. The maximum adsorption decreases in the order: benzoic acid, benzyl alcohol and benzylamine. (au) 54 refs.

  11. Increased power supplied to the shelf from land

    2002-01-01

    The report analyses how increasing the power supply from land to the offshore installations will affect the emissions of carbon dioxide from the power production on land. For the time being the CO 2 emissions from the production in existing power plants outside Norway will increase. Since the power price also rises, this checks the rise in consumption. This means that the total emission of carbon dioxide does not increase as much as it would have done if the power supply to the shelf had been covered entirely by increased production in existing coal power plants. If in the long term new conventional gas power capacity can be developed commercially, then increased power supply to the shelf will cause the CO 2 emission from power production on land in Norway to increase. Should conventional gas power plants not be granted concession, then the effect will be to increase the power production in existing plants in other countries and to check the rise in consumption. The net rise in consumption increases the emission of carbon dioxide from production in coal, oil, or gas power plants in Denmark, Finland, Germany or Poland

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

    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

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

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

    2006-09-30

    Despite declining production rates, existing reservoirs in the United States contain vast volumes of remaining oil that is not being effectively recovered. This oil resource constitutes a huge target for the development and application of modern, cost-effective technologies for producing oil. Chief among the barriers to the recovery of this oil are the high costs of designing and implementing conventional advanced recovery technologies in these mature, in many cases pressure-depleted, reservoirs. An additional, increasingly significant barrier is the lack of vital technical expertise necessary for the application of these technologies. This lack of expertise is especially notable among the small operators and independents that operate many of these mature, yet oil-rich, reservoirs. We addressed these barriers to more effective oil recovery by developing, testing, applying, and documenting an innovative technology that can be used by even the smallest operator to significantly increase the flow of oil from mature U.S. reservoirs. The Bureau of Economic Geology and Goldrus Producing Company assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The Permian Basin, the largest oil-bearing basin in North America, contains more than 70 billion barrels of remaining oil in place and is an ideal venue to validate this technology. We have demonstrated the potential of HPAI for oil-recovery improvement in preliminary laboratory tests and a reservoir pilot project. To more completely test the technology, this project emphasized detailed characterization of reservoir properties, which were integrated to access the effectiveness and economics of HPAI. The characterization phase of the project utilized geoscientists and petroleum engineers from the Bureau of Economic Geology and the Department of Petroleum

  14. Increased Oil Production and Reserves Utilizing Secondary/Tertiary Recovery Techniques on Small Reservoirs in the Paradox Basin, Utah

    Allison, M. Lee; Chidsey, Thomas Jr.

    1999-01-01

    The primary objective of this project is to enhance domestic petroleum production by demonstration and technology transfer of an advanced oil recovery technology in the Paradox basin, southeastern Utah. If this project can demonstrate technical and economic feasibility, the technique can be applied to about 100 additional small fields in the Paradox basin alone, and result in increased recovery of 150 to 200 million bbl of oil. This project is designed to characterize five shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation and choose the best candidate for a pilot demonstration project for either a waterflood or carbon dioxide-(CO-) flood 2 project. The field demonstration, monitoring of field performance, and associated validation activities will take place in the Paradox basin within the Navajo Nation. The results of this project will be transferred to industry and other researchers through a petroleum extension service, creation of digital databases for distribution, technical workshops and seminars, field trips, technical presentations at national and regional professional meetings, and publication in newsletters and various technical or trade journals

  15. Nutrient regeneration and oxygen demand in Bering Sea continental shelf sediments

    Rowe, Gilbert T.; Phoel, William C.

    1992-04-01

    Measurements of seabed oxygen demand and nutrient regeneration were made on continental shelf sediments in the southeast Bering Sea from 1 to 15 June 1981. The mean seabed oxygen demand was relatively modest (267 μM O 2 m -2 h -1), equivalent to a utilization of 60 mg organic carbon m -2 day -1. The seasonal build up of ammonium over the mid-shelf domain was generated at least in part by the bottom biota, as previously suggested ( WHITLEDGEet al., 1986 , Continental Shelf Research, 5, 109-132), but on the outer shelf nitrate replaced ammonium as the dominant inorganic nitrogen compound that was regenerated from the sediments. Comparison of oxygen consumption with the organic matter in sedimenting particulate matter (sampled with sediment traps) could imply that benthic processes were not accounting for the fate of considerable quantities of organic matter. Benthic oxygen demand rates, however, probably lag behind the input of the spring bloom to the bottom, thus extending the remineralization process out over time. Consumption by small microheterotrophs in the water column was also a likely sink, although shelf export and advective transport north were possible as well. Estimated nitrification rates in surface sediments could account for only a small fraction of the abrupt increase in nitrate observed in the water column over the shelf just prior to the spring bloom.

  16. Enhanced Open Ocean Storage of CO2 from Shelf Sea Pumping

    Thomas, H.; Bozec, Y.; Elkalay, K.; de Baar, H.J.W.

    2004-01-01

    Seasonal field observations show that the North Sea, a Northern European shelf sea, is highly efficient in pumping carbon dioxide fromthe atmosphere to the North Atlantic Ocean. The bottom topography–controlled stratification separates production and respiration processes in the North Sea, causing a

  17. Chalk as a reservoir

    Fabricius, Ida Lykke

    , and the best reservoir properties are typically found in mudstone intervals. Chalk mudstones vary a lot though. The best mudstones are purely calcitic, well sorted and may have been redeposited by traction currents. Other mudstones are rich in very fine grained silica, which takes up pore space and thus...... basin, so stylolite formation in the chalk is controlled by effective burial stress. The stylolites are zones of calcite dissolution and probably are the source of calcite for porefilling cementation which is typical in water zone chalk and also affect the reservoirs to different extent. The relatively...... have hardly any stylolites and can have porosity above 40% or even 50% and thus also have relatively high permeability. Such intervals have the problem though, that increasing effective stress caused by hydrocarbon production results in mechanical compaction and overall subsidence. Most other chalk...

  18. Sedimentary characteristics and controlling factors of shelf sand ridges in the Pearl River Mouth Basin, northeast of South China Sea

    Xiangtao Zhang

    2017-04-01

    Full Text Available Shelf sand ridge is a significant type of reservoir in the continental marginal basin, and it has drawn so much attention from sedimentologists and petroleum geologists. We were able to investigate the morphology, distribution, and sedimentary structures of shelf sand ridges systematically in this study based on the integration of high-resolution 3D seismic data, well logging, and cores. These shelf sand ridges are an asymmetrical mound-like structure in profiles, and they developed on an ancient uplift in the forced regression system tract and are onlapped by the overlying strata. In the plane, shelf sand ridges present as linear-shaped, which is different from the classical radial pattern; not to mention, they are separated into two parts by low amplitude tidal muddy channels. Corrugated bedding, tidal bedding, and scouring features are distinguished in cores of shelf sand ridges together with the coarsening up in lithology. All of these sedimentary characteristics indicate that shelf sand ridges deposited in the Pearl River Mouth Basin are reconstructed by the tidal and coastal current.

  19. Work reservoirs in thermodynamics

    Anacleto, Joaquim

    2010-01-01

    We stress the usefulness of the work reservoir in the formalism of thermodynamics, in particular in the context of the first law. To elucidate its usefulness, the formalism is then applied to the Joule expansion and other peculiar and instructive experimental situations, clarifying the concepts of configuration and dissipative work. The ideas and discussions presented in this study are primarily intended for undergraduate students, but they might also be useful to graduate students, researchers and teachers.

  20. Work reservoirs in thermodynamics

    Anacleto, Joaquim

    2010-05-01

    We stress the usefulness of the work reservoir in the formalism of thermodynamics, in particular in the context of the first law. To elucidate its usefulness, the formalism is then applied to the Joule expansion and other peculiar and instructive experimental situations, clarifying the concepts of configuration and dissipative work. The ideas and discussions presented in this study are primarily intended for undergraduate students, but they might also be useful to graduate students, researchers and teachers.

  1. Distribution of Al, Mn, Ni, Co & Cu in the non-lithogenous fractions of sediments of the northern half of the western continental shelf of India

    Murty, P.S.N.; Rao, Ch.M.; Paropkari, A.L.; Topgi, R.S.

    of the outer shelf region with high calcium carbonate content and all the elements covary with each other in the environment. From an evaluation of the role of different processes with the incorporation of elements, particularly trace elements...

  2. The Worldwide Marine Radiocarbon Reservoir Effect: Definitions, Mechanisms, and Prospects

    Alves, Eduardo Q.; Macario, Kita; Ascough, Philippa; Bronk Ramsey, Christopher

    2018-03-01

    When a carbon reservoir has a lower radiocarbon content than the atmosphere, this is referred to as a reservoir effect. This is expressed as an offset between the radiocarbon ages of samples from the two reservoirs at a single point in time. The marine reservoir effect (MRE) has been a major concern in the radiocarbon community, as it introduces an additional source of error that is often difficult to accurately quantify. For this reason, researchers are often reluctant to date marine material where they have another option. The influence of this phenomenon makes the study of the MRE important for a broad range of applications. The advent of Accelerator Mass Spectrometry (AMS) has reduced sample size requirements and increased measurement precision, in turn increasing the number of studies seeking to measure marine samples. These studies rely on overcoming the influence of the MRE on marine radiocarbon dates through the worldwide quantification of the local parameter ΔR, that is, the local variation from the global average MRE. Furthermore, the strong dependence on ocean dynamics makes the MRE a useful indicator for changes in oceanic circulation, carbon exchange between reservoirs, and the fate of atmospheric CO2, all of which impact Earth's climate. This article explores data from the Marine Reservoir Database and reviews the place of natural radiocarbon in oceanic records, focusing on key questions (e.g., changes in ocean dynamics) that have been answered by MRE studies and on their application to different subjects.

  3. Advantageous Reservoir Characterization Technology in Extra Low Permeability Oil Reservoirs

    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.

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

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

    1997-06-01

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

  5. Carbonization

    Hennebutte, H G; Goutal, E

    1921-07-04

    Materials such as coal, peat, or schist are subjected to a rising temperature in successive stages in apparatus in which the distillation products are withdrawn at each stage. For example in a three-stage process, the acid products of the first or low-temperature stage are fixed in a suitable reagent, the basic products from a second or higher-temperature stage are absorbed in an acid reagent, hydrocarbons being retained by solvents, while the third are subjected to a pyrogenation process carried out in a closed vessel. Wherein the material is subjected in stages to a rising temperature, the gasified products being withdrawn at each stage, and are prevented as far as possible from mixing with the carbonized products.

  6. Oil, gas potential in shallow water: Peru`s continental shelf basins

    Zuniga-Rivero, F.; Keeling, J.A.; Hay-Roe, H. [BPZ and Associates Inc., Houston, TX (United States)

    1998-11-16

    This third article of a series highlights the three sedimentary basins that underlie the 16 million acres of continental shelf adjacent to a 650-mile stretch of Peruvian coastline. This area lies roughly between the ports of Chiclayo and Pisco. These basins offer a variety of reservoirs, traps, and source-rock potential in water depths of less than 1,000 ft. They are characterized by a thick sequence of Neogene strata, underlain by Paleogene, Mesozoic, and Upper Paleozoic sediments down to as much as 7 sec two-way time on modern seismic records. In some places the sedimentary section may reach an aggregate thickness in excess of 50,000 ft. From north to south these contiguous shelf basins are the Sechura-Salaverry, Huacho, and Pisco basins. All three basins are described.

  7. Radiocarbon dates of sediment cores from inner continental shelf off Taingapatnam, southwest coast of India

    Nambiar, A.R.; Rajagopalan, G.

    1995-01-01

    Radiocarbon dating of carbonized wood samples from three sediment cores from the inner continental shelf off Taingapatnam, in the southwestern coast of India, indicates ages in the bracket 8400-9400 YBP. These radiometric ages correlate well with the ages of carbonized wood from inner continental shelf off Ponnani, Kerala and Karwar, Karnataka. The occurrence of carbonized wood in widely spread offshore areas probably represents a regional transgressive event in the west coast which resulted in submergence and destruction of coastal mangroves. The rate of sedimentation in the study area varies between 0.12 and 0.37 mm/yr, much lower than those reported from shelf areas north of Mangalore. The slow accumulation of sediments in the southern parts of the western continental shelf of India, as exemplified from the present study, may be due to very poor discharge and low bed load sediments of the west-flowing small rivers of this part of the peninsula and low concentration of suspended particulate matter in them. (author). 24 refs., 2 tabs., 2 figs

  8. An Evaluation of the Carbon Sequestration Potential of the Cambro-Ordovician Strata of the Illinois and Michigan Basins. Part 1. Evaluation of Phase 2 CO2 Injection Testing in the Deep Saline Gunter Sandstone Reservoir (Cambro-Ordovician Knox Group), Marvin Blan No. 1 Hancock County, Kentucky Part 2. Time-lapse Three-Dimensional Vertical Seismic Profile (3D-VSP) of Sequestration Target Interval with Injected Fluids

    Bowersox, Richard [Univ. of Illinois, Champaign, IL (United States); Hickman, John [Univ. of Illinois, Champaign, IL (United States); Leetaru, Hannes [Univ. of Illinois, Champaign, IL (United States)

    2012-12-20

    Part 1 of this report focuses on results of the western Kentucky carbon storage test, and provides a basis for evaluating injection and storage of supercritical CO2 in Cambro-Ordovician carbonate reservoirs throughout the U.S. Midcontinent. This test demonstrated that the Cambro- Ordovician Knox Group, including the Beekmantown Dolomite, Gunter Sandstone, and Copper Ridge Dolomite in stratigraphic succession from shallowest to deepest, had reservoir properties suitable for supercritical CO2 storage in a deep saline reservoir hosted in carbonate rocks, and that strata with properties sufficient for long-term confinement of supercritical CO2 were present in the deep subsurface. Injection testing with brine and CO2 was completed in two phases. The first phase, a joint project by the Kentucky Geological Survey and the Western Kentucky Carbon Storage Foundation, drilled the Marvin Blan No. 1 carbon storage research well and tested the entire Knox Group section in the open borehole – including the Beekmantown Dolomite, Gunter Sandstone, and Copper Ridge Dolomite – at 1152–2255 m, below casing cemented at 1116 m. During Phase 1 injection testing, most of the 297 tonnes of supercritical CO2 was displaced into porous and permeable sections of the lowermost Beekmantown below 1463 m and Gunter. The wellbore was then temporarily abandoned with a retrievable bridge plug in casing at 1105 m and two downhole pressure-temperature monitoring gauges below the bridge plug pending subsequent testing. Pressure and temperature data were recorded every minute for slightly more than a year, providing a unique record of subsurface reservoir conditions in the Knox. In contrast, Phase 2 testing, this study, tested a mechanically-isolated dolomitic-sandstone interval in the Gunter.

  9. Advances in photonic reservoir computing

    Van der Sande, Guy; Brunner, Daniel; Soriano, Miguel C.

    2017-05-01

    We review a novel paradigm that has emerged in analogue neuromorphic optical computing. The goal is to implement a reservoir computer in optics, where information is encoded in the intensity and phase of the optical field. Reservoir computing is a bio-inspired approach especially suited for processing time-dependent information. The reservoir's complex and high-dimensional transient response to the input signal is capable of universal computation. The reservoir does not need to be trained, which makes it very well suited for optics. As such, much of the promise of photonic reservoirs lies in their minimal hardware requirements, a tremendous advantage over other hardware-intensive neural network models. We review the two main approaches to optical reservoir computing: networks implemented with multiple discrete optical nodes and the continuous system of a single nonlinear device coupled to delayed feedback.

  10. Influence of estuaries on shelf foraminiferal species

    Nigam, R.

    Dabhol-bhatkal stretch of the west coast of India is marked by a number of estuaries. Cavarotalia annectens is selected to monitor the influence of these estuaries on the inner shelf foraminiferal fauna. The percentage distribution of this species...

  11. Southwest Florida Shelf Ecosystems Analysis Study

    National Oceanic and Atmospheric Administration, Department of Commerce — The Southwest Florida Shelf Ecosystems Analysis Study produced grain size analyses in the historic 073 format for 299 sea floor samples collected from October 25,...

  12. The shelf life of dyed polymethylmethacrylate dosimeters

    Bett, R.; Watts, M.F.; Plested, M.E.

    2002-01-01

    The long-term stability of the radiation response of Harwell Red 4034 and Amber 3042 Perspex Dosimeters has been monitored for more than 15 years, and the resulting data used in the justification of their shelf-life specifications

  13. Tidal Mixing at the Shelf Break

    Hogg, Nelson; Legg, Sonya

    2005-01-01

    The aim of this project was to study mixing forced by tidal flow over sudden changes in topographic slope such as near the shelf-break, using high-resolution nonhydrostatic numerical simulations employing the MIT gem...

  14. Encapsulated microsensors for reservoir interrogation

    Scott, Eddie Elmer; Aines, Roger D.; Spadaccini, Christopher M.

    2016-03-08

    In one general embodiment, a system includes at least one microsensor configured to detect one or more conditions of a fluidic medium of a reservoir; and a receptacle, wherein the receptacle encapsulates the at least one microsensor. In another general embodiment, a method include injecting the encapsulated at least one microsensor as recited above into a fluidic medium of a reservoir; and detecting one or more conditions of the fluidic medium of the reservoir.

  15. Plankton community respiration, net ecosystem metabolism, and oxygen dynamics on the Louisiana continental shelf: Implications for hypoxia

    Murrell, Michael C.; Stanley, Roman S.; Lehrter, John C.; Hagy, James D.

    2013-01-01

    We conducted a multi-year study of the Louisiana continental shelf (LCS) to better understand the linkages between water column metabolism and the formation of hypoxia (dissolved oxygen Continental Shelf Research, 29: 1861-1872) to estimate net water column metabolism. There was consistent evidence of net heterotrophy, particularly in western transects, and in deeper waters (>40 m depth), indicating a net organic carbon deficit on the LCS. We offer a simple scale argument to suggest that riverine and inshore coastal waters may be significant sources of organic carbon to account for this deficit. This study provided unprecedented, continental shelf scale coverage of heterotrophic metabolism, which is useful for constraining models of oxygen, carbon, and nutrient dynamics along the LCS.

  16. Radurisation of broilers for shelf life extension

    Bok, H.E.; Holzapfel, W.H.; Van der Linde, H.J.

    1982-01-01

    Radurization is discussed as a method for the shelf life extension of refrigerated chicken carcasses. One of the advantages is that radurization eliminates potential food pathogenic bacteria like Salmonella in the chicken carcasses. Materials and methods for the radurization of chicken are discussed. The objective of the investigation was to determine the influence of different irradiation doses and storage conditions on the microbiological shelf life and organoleptic quality of fresh broilers

  17. How ice shelf morphology controls basal melting

    Little, Christopher M.; Gnanadesikan, Anand; Oppenheimer, Michael

    2009-12-01

    The response of ice shelf basal melting to climate is a function of ocean temperature, circulation, and mixing in the open ocean and the coupling of this external forcing to the sub-ice shelf circulation. Because slope strongly influences the properties of buoyancy-driven flow near the ice shelf base, ice shelf morphology plays a critical role in linking external, subsurface heat sources to the ice. In this paper, the slope-driven dynamic control of local and area-integrated melting rates is examined under a wide range of ocean temperatures and ice shelf shapes, with an emphasis on smaller, steeper ice shelves. A 3-D numerical ocean model is used to simulate the circulation underneath five idealized ice shelves, forced with subsurface ocean temperatures ranging from -2.0°C to 1.5°C. In the sub-ice shelf mixed layer, three spatially distinct dynamic regimes are present. Entrainment of heat occurs predominately under deeper sections of the ice shelf; local and area-integrated melting rates are most sensitive to changes in slope in this "initiation" region. Some entrained heat is advected upslope and used to melt ice in the "maintenance" region; however, flow convergence in the "outflow" region limits heat loss in flatter portions of the ice shelf. Heat flux to the ice exhibits (1) a spatially nonuniform, superlinear dependence on slope and (2) a shape- and temperature-dependent, internally controlled efficiency. Because the efficiency of heat flux through the mixed layer decreases with increasing ocean temperature, numerical simulations diverge from a simple quadratic scaling law.

  18. Modified, Packaged Tortillas Have Long Shelf Life

    Bourland, Charles; Glaus-Late, Kimberly

    1995-01-01

    Tortillas made from modified recipe and sealed in low-pressure nitrogen in foil pouches in effort to increase their shelf life at room temperature. Preliminary tests show that shelf life of these tortillas at least five months; in contrast, commercial tortillas last only few days. Part of water in recipe replaced with glycerin. Particularly necessary to avoid Clostridium botulinum, which grows in anaerobic environments and produces deadly toxin that causes botulism.

  19. Evaluation of Frasnian Shale reservoir, case studywell DAK-1, Ahnet ...

    The evaluation of unconventional reservoir in term of future exploration plan where the geochemical data are not unavailable making us different results from logging and Gas Data However this paper aim to define Potential zone throught the estimation of total organic carbon(TOC) using Δ log R Method and thermal ...

  20. Evaluating Current Practices in Shelf Life Estimation.

    Capen, Robert; Christopher, David; Forenzo, Patrick; Huynh-Ba, Kim; LeBlond, David; Liu, Oscar; O'Neill, John; Patterson, Nate; Quinlan, Michelle; Rajagopalan, Radhika; Schwenke, James; Stroup, Walter

    2018-02-01

    The current International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) methods for determining the supported shelf life of a drug product, described in ICH guidance documents Q1A and Q1E, are evaluated in this paper. To support this evaluation, an industry data set is used which is comprised of 26 individual stability batches of a common drug product where most batches are measured over a 24 month storage period. Using randomly sampled sets of 3 or 6 batches from the industry data set, the current ICH methods are assessed from three perspectives. First, the distributional properties of the supported shelf lives are summarized and compared to the distributional properties of the true shelf lives associated with the industry data set, assuming the industry data set represents a finite population of drug product batches for discussion purposes. Second, the results of the ICH "poolability" tests for model selection are summarized and the separate shelf life distributions from the possible alternative models are compared. Finally, the ICH methods are evaluated in terms of their ability to manage risk. Shelf life estimates that are too long result in an unacceptable percentage of nonconforming batches at expiry while those that are too short put the manufacturer at risk of possibly having to prematurely discard safe and efficacious drug product. Based on the analysis of the industry data set, the ICH-recommended approach did not produce supported shelf lives that effectively managed risk. Alternative approaches are required.

  1. 41 CFR 101-27.205 - Shelf-life codes.

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Shelf-life codes. 101-27...-Management of Shelf-Life Materials § 101-27.205 Shelf-life codes. Shelf-life items shall be identified by use of a one-digit code to provide for uniform coding of shelf-life materials by all agencies. (a) The...

  2. Influence of Late Paleozoic Gondwana glaciations on the depositional evolution of the northern Pangean shelf, North Greenland, Svalbard and the Barents Sea

    Stemmerik, Lars

    2008-01-01

    Outcrop and subsurface data from the central northern margin of the Pangean shelf in North Greenland, Svalbard, and the Norwegian Barents Sea record the depositional response of a Northern Hemisphere subtropical shelf to Late Carboniferous-Early Permian (Bashkirian-Sakmarian) Gondwana glaciations....... The dominant motif is that of meters to tens of meters of exposure-capped cycles of carbonates, mixed carbonates, and siliciclastics and, in older stratigraphic levels, siliciclastics and gypsum. Halitegypsum-carbonate cycles developed in deeper, isolated basins. Individual cycles of carbonate and mixed...

  3. Geochemical record of Holocene to Recent sedimentation on the Western Indus continental shelf, Arabian Sea

    Limmer, David R.; BöNing, Philipp; Giosan, Liviu; Ponton, Camilo; KöHler, Cornelia M.; Cooper, Matthew J.; Tabrez, Ali R.; Clift, Peter D.

    2012-01-01

    We present a multiproxy geochemical analysis of two cores recovered from the Indus Shelf spanning the Early Holocene to Recent (<14 ka). Indus-23 is located close to the modern Indus River, while Indus-10 is positioned ˜100 km further west. The Holocene transgression at Indus-10 was over a surface that was strongly weathered during the last glacial sea level lowstand. Lower Holocene sediments at Indus-10 have higherɛNdvalues compared to those at the river mouth indicating some sediment supply from the Makran coast, either during the deposition or via reworking of older sediments outcropping on the shelf. Sediment transport from Makran occurred during transgressive intervals when sea level crossed the mid shelf. The sediment flux from non-Indus sources to Indus-10 peaked between 11 ka and 8 ka. A hiatus at Indus-23 from 8 ka until 1.3 ka indicates non-deposition or erosion of existing Indus Shelf sequences. HigherɛNdvalues seen on the shelf compared to the delta imply reworking of older delta sediments in building Holocene clinoforms. Chemical Index of Alteration (CIA), Mg/Al and Sr isotopes are all affected by erosion of detrital carbonate, which reduced through the Holocene. K/Al data suggest that silicate weathering peaked ca. 4-6 ka and was higher at Indus-10 compared to Indus-23. Fine-grained sediments that make up the shelf have geochemical signatures that are different from the coarser grained bulk sediments measured in the delta plain. The Indus Shelf data highlight the complexity of reconstructing records of continental erosion and provenance in marine settings.

  4. Cesium reservoir and interconnective components

    1994-03-01

    The program objective is to demonstrate the technology readiness of a TFE (thermionic fuel element) suitable for use as the basic element in a thermionic reactor with electric power output in the 0.5 to 5.0 MW range. A thermionic converter must be supplied with cesium vapor for two reasons. Cesium atoms adsorbed on the surface of the emitter cause a reduction of the emitter work function to permit high current densities without excessive heating of the emitter. The second purpose of the cesium vapor is to provide space-charge neutralization in the emitter-collector gap so that the high current densities may flow across the gap unattenuated. The function of the cesium reservoir is to provide a source of cesium atoms, and to provide a reserve in the event that cesium is lost from the plasma by any mechanism. This can be done with a liquid cesium metal reservoir in which case it is heated to the desired temperature with auxiliary heaters. In a TFE, however, it is desirable to have the reservoir passively heated by the nuclear fuel. In this case, the reservoir must operate at a temperature intermediate between the emitter and the collector, ruling out the use of liquid reservoirs. Integral reservoirs contained within the TFE will produce cesium vapor pressures in the desired range at typical electrode temperatures. The reservoir material that appears to be the best able to meet requirements is graphite. Cesium intercalates easily into graphite, and the cesium pressure is insensitive to loading for a given intercalation stage. The goals of the cesium reservoir test program were to verify the performance of Cs-graphite reservoirs in the temperature-pressure range of interest to TFE operation, and to test the operation of these reservoirs after exposure to a fast neutron fluence corresponding to seven year mission lifetime. In addition, other materials were evaluated for possible use in the integral reservoir

  5. Arsenic enrichment in shelf and coastal sediment of the Brazilian subtropics

    Mirlean, N.; Medeanic, S.; Garcia, F. A.; Travassos, M. P.; Baisch, P.

    2012-03-01

    High levels of As (i.e., above the nationally legislated threshold of 70 mg kg-1) were found in shelf sediment of the Espirito Santo state of Brazil. The elevated content of this metalloid propagated in the sediment to a depth of approximately 1.5 m. The adjacent beach sands and mangrove sediments were also enriched in As. The variation in As levels along the shelf sediment profiles was acompained by calcareous-material distribution, which reflects the paleogeographical circumstances that promote local reef development during the corresponding intervals of sedimentation. Arsenic-rich calcareous bioclast materials migrate to a beach from the surface horizon of nearby shelf sediment, thereby replacing the part of the As that previously entered the marine environment with eroded material from the continent to the littoral zone. The segment of the Brazilian tropical shelf that was studied clearly demonstrated that the As enrichment of the shelf sediment is determined by the exposure of the Barreiras formation on the coast and the development of reefs, which are favorable sites for the settling of bodies of biogenic carbonates.

  6. Reservoir engineering and hydrogeology

    Anon.

    1983-01-01

    Summaries are included which show advances in the following areas: fractured porous media, flow in single fractures or networks of fractures, hydrothermal flow, hydromechanical effects, hydrochemical processes, unsaturated-saturated systems, and multiphase multicomponent flows. The main thrust of these efforts is to understand the movement of mass and energy through rocks. This has involved treating fracture rock masses in which the flow phenomena within both the fractures and the matrix must be investigated. Studies also address the complex coupling between aspects of thermal, hydraulic, and mechanical processes associated with a nuclear waste repository in a fractured rock medium. In all these projects, both numerical modeling and simulation, as well as field studies, were employed. In the theoretical area, a basic understanding of multiphase flow, nonisothermal unsaturated behavior, and new numerical methods have been developed. The field work has involved reservoir testing, data analysis, and case histories at a number of geothermal projects

  7. FRACTURED PETROLEUM RESERVOIRS

    Abbas Firoozabadi

    1999-06-11

    The four chapters that are described in this report cover a variety of subjects that not only give insight into the understanding of multiphase flow in fractured porous media, but they provide also major contribution towards the understanding of flow processes with in-situ phase formation. In the following, a summary of all the chapters will be provided. Chapter I addresses issues related to water injection in water-wet fractured porous media. There are two parts in this chapter. Part I covers extensive set of measurements for water injection in water-wet fractured porous media. Both single matrix block and multiple matrix blocks tests are covered. There are two major findings from these experiments: (1) co-current imbibition can be more efficient than counter-current imbibition due to lower residual oil saturation and higher oil mobility, and (2) tight fractured porous media can be more efficient than a permeable porous media when subjected to water injection. These findings are directly related to the type of tests one can perform in the laboratory and to decide on the fate of water injection in fractured reservoirs. Part II of Chapter I presents modeling of water injection in water-wet fractured media by modifying the Buckley-Leverett Theory. A major element of the new model is the multiplication of the transfer flux by the fractured saturation with a power of 1/2. This simple model can account for both co-current and counter-current imbibition and computationally it is very efficient. It can be orders of magnitude faster than a conventional dual-porosity model. Part II also presents the results of water injection tests in very tight rocks of some 0.01 md permeability. Oil recovery from water imbibition tests from such at tight rock can be as high as 25 percent. Chapter II discusses solution gas-drive for cold production from heavy-oil reservoirs. The impetus for this work is the study of new gas phase formation from in-situ process which can be significantly

  8. Mean Lagrangian drift in continental shelf waves

    Drivdal, M.; Weber, J. E. H.

    2012-04-01

    The time- and depth-averaged mean drift induced by barotropic continental shelf waves (CSW's) is studied theoretically for idealized shelf topography by calculating the mean volume fluxes to second order in wave amplitude. The waves suffer weak spatial damping due to bottom friction, which leads to radiation stress forcing of the mean fluxes. In terms of the total wave energy density E¯ over the shelf region, the radiation stress tensor component S¯11 for CSW's is found to be different from that of shallow water surface waves in a non-rotating ocean. For CSW's, the ratio ¯S11/¯E depends strongly on the wave number. The mean Lagrangian flow forced by the radiation stress can be subdivided into a Stokes drift and a mean Eulerian drift current. The magnitude of the latter depends on the ratio between the radiation stress and the bottom stress acting on the mean flow. When the effect of bottom friction acts equally strong on the waves and the mean current, calculations for short CSW's show that the Stokes drift and the friction-dependent wave-induced mean Eulerian current varies approximately in anti-phase over the shelf, and that the latter is numerically the largest. For long CSW's they are approximately in phase. In both cases the mean Lagrangian current, which is responsible for the net particle drift, has its largest numerical value at the coast on the shallow part of the shelf. Enhancing the effect of bottom friction on the Eulerian mean flow, results in a general current speed reduction, as well as a change in spatial structure for long waves. Applying realistic physical parameters for the continental shelf west of Norway, calculations yield along-shelf mean drift velocities for short CSW's that may be important for the transport of biological material, neutral tracers, and underwater plumes of dissolved oil from deep water drilling accidents.

  9. Reservoir sedimentation; a literature survey

    Sloff, C.J.

    1991-01-01

    A survey of literature is made on reservoir sedimentation, one of the most threatening processes for world-wide reservoir performance. The sedimentation processes, their impacts, and their controlling factors are assessed from a hydraulic engineering point of view with special emphasis on

  10. Interaction Between Shelf Layout and Marketing Effectiveness and Its Impact On Optimizing Shelf Arrangements

    J.E.M. van Nierop; D. Fok (Dennis); Ph.H.B.F. Franses (Philip Hans)

    2006-01-01

    textabstractAllocating the proper amount of shelf space to stock keeping units [SKUs] is an increasingly relevant and difficult topic for managers. Shelf space is a scarce resource and it has to be distributed across a larger and larger number of items. It is in particular important because the

  11. Interaction Between Shelf Layout and Marketing Effectiveness and Its Impact on Optimizing Shelf Arrangements

    van Nierop, Erjen; Fok, Dennis; Franses, Philip Hans

    2008-01-01

    In this paper, we propose and operationalize a new method for optimizing shelf arrangements. We show that there are important dependencies between the layout of the shelf and stock-keeping unit (SKU) sales and marketing effectiveness. The importance of these dependencies is further shown by the

  12. Advances in photonic reservoir computing

    Van der Sande Guy

    2017-05-01

    Full Text Available We review a novel paradigm that has emerged in analogue neuromorphic optical computing. The goal is to implement a reservoir computer in optics, where information is encoded in the intensity and phase of the optical field. Reservoir computing is a bio-inspired approach especially suited for processing time-dependent information. The reservoir’s complex and high-dimensional transient response to the input signal is capable of universal computation. The reservoir does not need to be trained, which makes it very well suited for optics. As such, much of the promise of photonic reservoirs lies in their minimal hardware requirements, a tremendous advantage over other hardware-intensive neural network models. We review the two main approaches to optical reservoir computing: networks implemented with multiple discrete optical nodes and the continuous system of a single nonlinear device coupled to delayed feedback.

  13. Spatially pooled depth-dependent reservoir storage, elevation, and water-quality data for selected reservoirs in Texas, January 1965-January 2010

    Burley, Thomas E.; Asquith, William H.; Brooks, Donald L.

    2011-01-01

    temperature, reservoir storage, reservoir elevation, specific conductance, dissolved oxygen, pH, unfiltered salinity, unfiltered total nitrogen, filtered total nitrogen, unfiltered nitrate plus nitrite, unfiltered phosphorus, filtered phosphorus, unfiltered carbon, carbon in suspended sediment, total hardness, unfiltered noncarbonate hardness, filtered noncarbonate hardness, unfiltered calcium, filtered calcium, unfiltered magnesium, filtered magnesium, unfiltered sodium, filtered sodium, unfiltered potassium, filtered potassium, filtered chloride, filtered sulfate, unfiltered fluoride, and filtered fluoride. When possible, USGS and Texas Commission on Environmental Quality water-quality properties and constituents were matched using the database parameter codes for individual physical properties and constituents, descriptions of each physical property or constituent, and their reporting units. This report presents a collection of delimited text files of source-aggregated, spatially pooled, depth-dependent, instantaneous water-quality data as well as instantaneous, daily, and monthly storage and elevation reservoir data.

  14. CARBON AND OXYGEN ISOTOPIC ANALYSIS: BUG, CHEROKEE, AND PATTERSON CANYON FIELDS, SAN JUAN COUNTY, UTAH

    David E. Eby; Thomas C. Chidsey Jr; Kevin McClure; Craig D. Morgan; Stephen T. Nelson

    2003-12-01

    Over 400 million barrels (64 million m{sup 3}) of oil have been produced from the shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation in the Paradox Basin, Utah and Colorado. With the exception of the giant Greater Aneth field, the other 100 plus oil fields in the basin typically contain 2 to 10 million barrels (0.3-1.6 million m{sup 3}) of original oil in place. Most of these fields are characterized by high initial production rates followed by a very short productive life (primary), and hence premature abandonment. Only 15 to 25 percent of the original oil in place is recoverable during primary production from conventional vertical wells. An extensive and successful horizontal drilling program has been conducted in the giant Greater Aneth field. However, to date, only two horizontal wells have been drilled in small Ismay and Desert Creek fields. The results from these wells were disappointing due to poor understanding of the carbonate facies and diagenetic fabrics that create reservoir heterogeneity. These small fields, and similar fields in the basin, are at high risk of premature abandonment. At least 200 million barrels (31.8 million m{sup 3}) of oil will be left behind in these small fields because current development practices leave compartments of the heterogeneous reservoirs undrained. Through proper geological evaluation of the reservoirs, production may be increased by 20 to 50 percent through the drilling of low-cost single or multilateral horizontal legs from existing vertical development wells. In addition, horizontal drilling from existing wells minimizes surface disturbances and costs for field development, particularly in the environmentally sensitive areas of southeastern Utah and southwestern Colorado.

  15. Shelf Life Prediction for Canned Gudeg using Accelerated Shelf Life Testing (ASLT) Based on Arrhenius Method

    Nurhayati, R.; Rahayu NH, E.; Susanto, A.; Khasanah, Y.

    2017-04-01

    Gudeg is traditional food from Yogyakarta. It is consist of jackfruit, chicken, egg and coconut milk. Gudeg generally have a short shelf life. Canning or commercial sterilization is one way to extend the shelf life of gudeg. This aims of this research is to predict the shelf life of Andrawinaloka canned gudeg with Accelerated Shelf Life Test methods, Arrhenius model. Canned gudeg stored at three different temperature, there are 37, 50 and 60°C for two months. Measuring the number of Thio Barbituric Acid (TBA), as a critical aspect, were tested every 7 days. Arrhenius model approach is done with the equation order 0 and order 1. The analysis showed that the equation of order 0 can be used as an approach to estimating the shelf life of canned gudeg. The storage of Andrawinaloka canned gudeg at 30°C is predicted untill 21 months and 24 months for 25°C.

  16. Geochemistry and microbiology data collected from bottle casts from the R/V HERMANO GINES from the continental shelf of Venezuela in support of the Carbon Retention in a Colored Ocean (CARIACO) project from 19 January to 7 December 2010 (NODC Accession 0066503)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains bottle data collected aboard the R/V HERMANO GINES from the continental shelf of Venezuela during 19 January, 2009 (CAR-153); 16 May to 17...

  17. Physical, chemical and biological data collected from CTD and bottle casts from the R/V HERMANO GINES from the Caribbean Sea and continental shelf of Venezuela in support of the Carbon Retention in a Colored Ocean (CARIACO) project from 2008 - 2010 (NODC Accession 0069000)

    National Oceanic and Atmospheric Administration, Department of Commerce — CTD and bottle data were collected from R/V HERMANO GINES on the continental shelf of Venezuela from 10 September 2008 to 7 January 2010, during cruises Car149...

  18. Physical, chemical, and nutrient data collected from CTD and bottle casts from the R/V HERMANO GINES from the continental shelf of Venezuela in support of the Carbon Retention in a Colored Ocean (CARIACO) project from 10 April 2007 to 05 August December 2008 (NODC Accession 0056729)

    National Oceanic and Atmospheric Administration, Department of Commerce — CTD and bottle data were collected from R/V HERMANO GINES on the continental shelf of Venezuela from 10 April 2007 to 05 August 2008. Data were collected by the...

  19. Analysis of real-time reservoir monitoring : reservoirs, strategies, & modeling.

    Mani, Seethambal S.; van Bloemen Waanders, Bart Gustaaf; Cooper, Scott Patrick; Jakaboski, Blake Elaine; Normann, Randy Allen; Jennings, Jim (University of Texas at Austin, Austin, TX); Gilbert, Bob (University of Texas at Austin, Austin, TX); Lake, Larry W. (University of Texas at Austin, Austin, TX); Weiss, Chester Joseph; Lorenz, John Clay; Elbring, Gregory Jay; Wheeler, Mary Fanett (University of Texas at Austin, Austin, TX); Thomas, Sunil G. (University of Texas at Austin, Austin, TX); Rightley, Michael J.; Rodriguez, Adolfo (University of Texas at Austin, Austin, TX); Klie, Hector (University of Texas at Austin, Austin, TX); Banchs, Rafael (University of Texas at Austin, Austin, TX); Nunez, Emilio J. (University of Texas at Austin, Austin, TX); Jablonowski, Chris (University of Texas at Austin, Austin, TX)

    2006-11-01

    The project objective was to detail better ways to assess and exploit intelligent oil and gas field information through improved modeling, sensor technology, and process control to increase ultimate recovery of domestic hydrocarbons. To meet this objective we investigated the use of permanent downhole sensors systems (Smart Wells) whose data is fed real-time into computational reservoir models that are integrated with optimized production control systems. The project utilized a three-pronged approach (1) a value of information analysis to address the economic advantages, (2) reservoir simulation modeling and control optimization to prove the capability, and (3) evaluation of new generation sensor packaging to survive the borehole environment for long periods of time. The Value of Information (VOI) decision tree method was developed and used to assess the economic advantage of using the proposed technology; the VOI demonstrated the increased subsurface resolution through additional sensor data. Our findings show that the VOI studies are a practical means of ascertaining the value associated with a technology, in this case application of sensors to production. The procedure acknowledges the uncertainty in predictions but nevertheless assigns monetary value to the predictions. The best aspect of the procedure is that it builds consensus within interdisciplinary teams The reservoir simulation and modeling aspect of the project was developed to show the capability of exploiting sensor information both for reservoir characterization and to optimize control of the production system. Our findings indicate history matching is improved as more information is added to the objective function, clearly indicating that sensor information can help in reducing the uncertainty associated with reservoir characterization. Additional findings and approaches used are described in detail within the report. The next generation sensors aspect of the project evaluated sensors and packaging

  20. Geophysical and geological investigations of subsurface reservoirs : case studies of Spitsbergen, Norway

    Baelum, Karoline

    2011-07-01

    and carbonate reservoirs of the basin. Of special interest as a reservoir play analogue are the paleokarst features on Wordiekammen, a mountain close to the BFZ within the Billefjorden Trough. Similar plays have been and are explored on the Loppa High in the Barents Shelf The target of the investigation was series of infilled karst pipes located on top of (under a layer of sediment) and along the edges of the plateau that caps half of the mountain. The methods employed were Ground Penetration Radar (GPR) and geoelectric measurements. The porosity and chaotic geophysical reflection pattern of the collapse breccia infill in the pipes in contrast to the surrounding allowed for an well-constrained identification of the geometry and location of the pipes via closely sampled 2D and 3D GPR surveys. More than 20 breccia pipes were identified in the data with diameters of 10-80 m, showing geometries very similar to the pipes outcropping along the mountain edge. The geoelectric investigations revealed a strong link between resistivity anomalies and the position of the Karst pipes, although this is likely linked to the presence and composition of pore water. However, the exact relationship is yet to be determined. The high porosity and possible subsurface physical linkage of the collapse breccias confirm their value as interesting reservoirs analogues. The second topic concerns the subsurface geology around Longyearbyen in connection with the identification and quantification of a possible reservoir for future CO{sub 2}-storage. Results from this work are obtained via a combination of seismic data, drill cores and electrical logs from four drill holes with a maximum depth of 980 m, and in addition Lidar scans in connection with investigations of outcrops. The targeted Kapp Toscana Group reservoir, found below a cap rock section of Jurassic shales and mudstone, offers the c. 270 m thick De Geerdalen Formation topped by the 22 m thick Wilhelmoeya Subgroup. The reservoir section

  1. Nepheloid Layers: Origin and Development In A Narrow Continental Shelf (nw Portugal)

    Oliveira, A.; Vitorino, J.; Rodrigues, A.; Jouanneau, J. M.; Weber, O.; Dias, J. A.

    A general hydrographic, nephelometric and sedimentological surveying of the NW Portuguese continental shelf and slope was undertaken, under winter and spring con- ditions in order to elaborate a conceptual model of suspended sediments (nepheloid layer) dynamics. Two major situations were found: 1) Spring/Summer - with northerly winds (upwelling) and low energetic wave regime that favour the deposition of sedi- ments. The northerly winds promote offshore transport in the surface nepheloid layer (SNL) and the establishment of a seasonal thermocline allow the expansion of the SNL to the west. The SNL can reach or even cross the shelf-break (50 km from coastline). Particulate organic carbon (POC) content in this layer highlights the higher contribution of biogenic particles (average concentration of 22%); 2) Winter, with southerly winds (downwelling) and high energetic wave regime that favour mid- shelf sediments resuspension and offshore transport in the bottom nepheloid layer (BNL). In the shelf-break the BNL detached to form intermediate nepheloid layers (INL). The SNL is restricted to the inner shelf. The effect of southerly winds gener- ates shoreward Ekman transport and detains the offshore westward extension of this layer even during high river run-off periods. The POC content indicates a dominance of litogenic particles in suspension (average concentration of 8%). Over the mid- and inner-shelf the dominant resuspension mechanism is associated with surface waves (Vitorino et al., 2002). Estimates based on wave measurements at mid-shelf (86m depth) suggested that, in winter, the wave shear velocity frequently exceeds 1 cm/s, assumed as the critical shear velocity for the resuspension of the fine grained sedi- ments (34m) of the bottom cover. Storm events, such as the one observed in November 1996 easily increase the wave shear velocities over 3 cm/s, leading to the increase of the BNL thickness (20-30m) (Vitorino et al., 2002; Oliveira et al., 2002). Low

  2. Understanding the True Stimulated Reservoir Volume in Shale Reservoirs

    Hussain, Maaruf; Saad, Bilal; Negara, Ardiansyah; Sun, Shuyu

    2017-01-01

    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

  3. Seasonal and interannual cross-shelf transport over the Texas and Louisiana continental shelf

    Thyng, Kristen M.; Hetland, Robert D.

    2018-05-01

    Numerical drifters are tracked in a hydrodynamic simulation of circulation over the Texas-Louisiana shelf to analyze patterns in cross-shelf transport of materials. While the important forcing mechanisms in the region (wind, river, and deep eddies) and associated flow patterns are known, the resultant material transport is less well understood. The primary metric used in the calculations is the percent of drifters released within a region that cross the 100 m isobath. Results of the analysis indicate that, averaged over the eleven years of the simulation, there are two regions on the shelf - over the Texas shelf during winter, and over the Louisiana shelf in summer - with increased seasonal probability for offshore transport. Among the two other distinct regions, the big bend region in Texas has increased probability for onshore transport, and the Mississippi Delta region has an increase in offshore transport, for both seasons. Some of these regions of offshore transport have marked interannual variability. This interannual variability is correlated to interannual changes in forcing conditions. Winter transport off of the Texas shelf is correlated with winter mean wind direction, with more northerly winds enhancing offshore transport; summer transport off the Louisiana shelf is correlated with Mississippi River discharge.

  4. Tidal Modulation of Ice-shelf Flow: a Viscous Model of the Ross Ice Shelf

    Brunt, Kelly M.; MacAyeal, Douglas R.

    2014-01-01

    Three stations near the calving front of the Ross Ice Shelf, Antarctica, recorded GPS data through a full spring-neap tidal cycle in November 2005. The data revealed a diurnal horizontal motion that varied both along and transverse to the long-term average velocity direction, similar to tidal signals observed in other ice shelves and ice streams. Based on its periodicity, it was hypothesized that the signal represents a flow response of the Ross Ice Shelf to the diurnal tides of the Ross Sea. To assess the influence of the tide on the ice-shelf motion, two hypotheses were developed. The first addressed the direct response of the ice shelf to tidal forcing, such as forces due to sea-surface slopes or forces due to sub-ice-shelf currents. The second involved the indirect response of ice-shelf flow to the tidal signals observed in the ice streams that source the ice shelf. A finite-element model, based on viscous creep flow, was developed to test these hypotheses, but succeeded only in falsifying both hypotheses, i.e. showing that direct tidal effects produce too small a response, and indirect tidal effects produce a response that is not smooth in time. This nullification suggests that a combination of viscous and elastic deformation is required to explain the observations.

  5. Facies and porosity origin of reservoirs: Case studies from the Cambrian Longwangmiao Formation of Sichuan Basin, China, and their implications on reservoir prediction

    Anjiang Shen

    2018-02-01

    Full Text Available The dolostone of the Cambrian Longwangmiao Formation has been a significant gas exploration area in Sichuan Basin. In Gaoshiti-Moxi regions, a giant gas pool with thousands of billion cubic meters' reserve has been discovered. However, the origin of the reservoir and the distribution patterns are still disputed, eventually constraining the dolostone exploration of the Longwangmiao Formation. This paper focuses on the characteristics, origin, and distribution patterns of the dolostone reservoir in the Longwangmiao Formation based on: the outcrop geological survey, cores, thin-sections observation, reservoir geochemical characteristics study, and reservoir simulation experiments. As a result, two realizations were acquired: (1 The Cambrian Longwangmiao Formation could be divided into upper and lower part in Sichuan Basin. Based on the two parts of the Longwangmiao Formation, two lithofacies paleogeographic maps were generated. In addition, the carbonate slope sedimentary models were established. The grainstone shoals are mainly distributed in the shallow slope of the upper part in the Longwangmiao Formation. (2 The grainstone shoals are the developing basis of the dolostone reservoir in the Longwangmiao Formation. Moreover, the contemporaneous dissolution was a critical factor of grainstone shoal reservoir development in the Longwangmiao Formation. Controlled by the exposure surface, the dissolution vugs are not only extensively distributed, but also successively developed along the contemporaneous pore zones. Hence, the distribution patterns could be predicted. The geological understandings of the origin of dolostone reservoir in the Longwangmiao Formation show that the reservoir distributed in the areas of karstification in the Gaoshiti-Moxi regions, as well as the widespread grainstone shoals in the whole basin, are the potential exploration targets. Keywords: Sichuan Basin, Longwangmiao Formation, Carbonate slope, Dolograinstone shoal

  6. Design Techniques and Reservoir Simulation

    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.

  7. The Characteristics of Spanish Reservoirs

    Armengol, J; Merce, R

    2003-01-01

    Sau Reservoir was first filled in 1963 in a middle stretch of the Ter River, as part of a multi-use scheme, including hydroelectric power, agricultural irrigation, domestic and industrial water supply...

  8. Understanding the True Stimulated Reservoir Volume in Shale Reservoirs

    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

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

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

    1992-10-01

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

  10. Holocene sea levels of Visakhapatnam shelf, east coast of India

    Rao, K.M.; Rao, T.C.S.

    The Holocene sea level changes in the shelf areas off Visakhapatnam was studied from sediment distribution pattern and shallow seismic profiling. Morphological features on the shelf indicate a Late Pleistocene regression down to about -130 m below...

  11. Sonograph patterns of the central western continental shelf of India

    Rao, P.S.

    knolls. A transition zone with tonal variations is present between 40 and 60 m water depth. Ground-truth data sediment and rock distribution maps indicate depositional (inner shelf), nondepositional or erosional (outer shelf) environments and a...

  12. Food packaging and shelf life: a practical guide

    Robertson, Gordon L

    2010-01-01

    .... Food Packaging and Shelf Life: A Practical Guide provides package developers with the information they need to specify just the right amount of protective packaging to maintain food quality and maximize shelf life...

  13. Seabottom backscatter studies in the western continental shelf of India

    Chakraborty, B.; Pathak, D.

    The study is initiated to observe the interaction effects of the sound signal with three different sediment bottoms in the shelf area between Cochin and Mangalore in the western continental shelf of India. An echo signal acquisition system has been...

  14. 75 FR 1076 - Outer Continental Shelf Civil Penalties

    2010-01-08

    ... initiate civil penalty proceedings; however, violations that cause injury, death, or environmental damage... DEPARTMENT OF THE INTERIOR Minerals Management Service Outer Continental Shelf Civil Penalties... daily civil penalty assessment. SUMMARY: The Outer Continental Shelf Lands Act requires the MMS to...

  15. Magnetic surveys of the continental shelf off Visakhapatnam

    Rao, T.C.S.; Murthy, K.S.R.

    shelf. Quantitative estimates made for the anomalies over the inner shelf using the graphical method and by computing the analytical signal suggest the existence of a fault in the nearshore region and a possible zone of heavy mineral concentration off...

  16. The role of open ocean boundary forcing on seasonal to decadal-scale variability and long-term change of natural shelf hypoxia

    Monteiro, Pedro M S; Dewitte, Boris; Paulmier, Aurelien; Scranton, Mary I; Van der Plas, Anja K

    2011-01-01

    In this study we investigate the possible reasons for the widespread differences between the seasonal cycles of carbon production and export compared to those of hypoxia in eastern boundary upwelling systems. An idealized model is proposed that qualitatively characterizes the relative roles of physics and biogeochemical fluxes. The model is tested on three contrasting upwelling systems: the Benguela (from relatively aerated to interannual anoxic), the Humboldt (sub-oxic and interannually anoxic) and the Cariaco (permanently anoxic). Overall we propose that shelf hypoxia variability can be explained on the basis of the interaction between ventilation by ocean boundary forcing through ocean-shelf exchange and the role of shelf geometry in the retention of shelf-based particulate organic carbon (POC) fluxes. We aim to identify the hypoxia regimes associated with low ventilation-wide-shelf systems and high ventilation-narrow-shelf systems, considering them as extremes of conditions controlled by the two factors. We propose that this may help to explain differences in the seasonal cycles of the biogeochemical drivers and responses as well as difference between upwelling systems and within individual upwelling systems. It is suggested that when seasonal hypoxia emerges it does so preferentially at a wide-shelf part of a system.

  17. Chickamauga reservoir embayment study - 1990

    Meinert, D.L.; Butkus, S.R.; McDonough, T.A.

    1992-12-01

    The objectives of this report are three-fold: (1) assess physical, chemical, and biological conditions in the major embayments of Chickamauga Reservoir; (2) compare water quality and biological conditions of embayments with main river locations; and (3) identify any water quality concerns in the study embayments that may warrant further investigation and/or management actions. Embayments are important areas of reservoirs to be considered when assessments are made to support water quality management plans. In general, embayments, because of their smaller size (water surface areas usually less than 1000 acres), shallower morphometry (average depth usually less than 10 feet), and longer detention times (frequently a month or more), exhibit more extreme responses to pollutant loadings and changes in land use than the main river region of the reservoir. Consequently, embayments are often at greater risk of water quality impairments (e.g. nutrient enrichment, filling and siltation, excessive growths of aquatic plants, algal blooms, low dissolved oxygen concentrations, bacteriological contamination, etc.). Much of the secondary beneficial use of reservoirs occurs in embayments (viz. marinas, recreation areas, parks and beaches, residential development, etc.). Typically embayments comprise less than 20 percent of the surface area of a reservoir, but they often receive 50 percent or more of the water-oriented recreational use of the reservoir. This intensive recreational use creates a potential for adverse use impacts if poor water quality and aquatic conditions exist in an embayment.

  18. Cosmetics Safety Q&A: Shelf Life

    ... of cosmetics? The shelf life for eye-area cosmetics is more limited than for other products. Because of repeated microbial exposure during use by the consumer and the risk of eye infections, some industry experts recommend replacing mascara 3 months after purchase. ...

  19. Coordination: Southeast Continental Shelf studies. Progress report

    Menzel, D.W.

    1981-02-01

    An overview of the Oceanograhic Program of Skidaway Institute of Oceanograhy is presented. Included are the current five year plan for studies of the Southeast Continental Shelf, a summary of research accomplishments, proposed research for 1981-1982, current status of the Savannah Navigational Light Tower, and a list of publications. (ACR)

  20. Impacts of water quality variation and rainfall runoff on Jinpen Reservoir, in Northwest China

    Zi-zhen Zhou

    2015-10-01

    Full Text Available The seasonal variation characteristics of the water quality of the Jinpen Reservoir and the impacts of rainfall runoff on the reservoir were investigated. Water quality monitoring results indicated that, during the stable stratification period, the maximum concentrations of total nitrogen, total phosphorus, ammonia nitrogen, total organic carbon, iron ion, and manganese ion in the water at the reservoir bottom on September 6 reached 2.5 mg/L, 0.12 mg/L, 0.58 mg/L, 3.2 mg/L, 0.97 mg/L, and 0.32 mg/L, respectively. Only heavy storm runoff can affect the main reservoir and cause the water quality to seriously deteriorate. During heavy storms, the stratification of the reservoir was destroyed, and the reservoir water quality consequently deteriorated due to the high-turbidity particulate phosphorus and organic matter in runoff. The turbidity and concentrations of total phosphorus and total organic carbon in the main reservoir increased to 265 NTU, 0.224 mg/L, and 3.9 mg/L, respectively. Potential methods of dealing with the water problems in the Jinpen Reservoir are proposed. Both in stratification and in storm periods, the use of measures such as adjusting intake height, storing clean water, and releasing turbid flow can be helpful to safeguarding the quality of water supplied to the water treatment plants.

  1. Size-dependent photoacclimation of the phytoplankton community in temperate shelf waters (southern Bay of Biscay)

    Álvarez, E

    2015-12-09

    © Inter-Research 2016. Shelf waters of the Cantabrian Sea (southern Bay of Biscay) are productive ecosystems with a marked seasonality. We present the results from 1 yr of monthly monitoring of the phytoplankton community together with an intensive sampling carried out in 2 contrasting scenarios during the summer and autumn in a mid-shelf area. Stratification was apparent on the shelf in summer, while the water column was comparatively well mixed in autumn. The size structure of the photoautotrophic community, from pico-to micro-phytoplankton, was tightly coupled with the meteo-climatic and hydrographical conditions. Over the short term, variations in the size structure and chlorophyll content of phytoplankton cells were related to changes in the physico-chemical environment, through changes in the availability of nutrients and light. Uncoupling between the dynamics of carbon biomass and chlorophyll resulted in chlorophyll to carbon ratios dependent on body size. The slope of the size dependence of chlorophyll content increased with increasing irradiance, reflecting different photoacclimation plasticity from pico-to micro-phytoplankton. The results have important implications for the productivity and the fate of biogenic carbon in this region, since the size dependence of photosynthetic rates is directly related to the size scaling of chlorophyll content.

  2. Size-dependent photoacclimation of the phytoplankton community in temperate shelf waters (southern Bay of Biscay)

    Á lvarez, E; Moran, Xose Anxelu G.; Ló pez-Urrutia, Á ; Nogueira, E

    2015-01-01

    © Inter-Research 2016. Shelf waters of the Cantabrian Sea (southern Bay of Biscay) are productive ecosystems with a marked seasonality. We present the results from 1 yr of monthly monitoring of the phytoplankton community together with an intensive sampling carried out in 2 contrasting scenarios during the summer and autumn in a mid-shelf area. Stratification was apparent on the shelf in summer, while the water column was comparatively well mixed in autumn. The size structure of the photoautotrophic community, from pico-to micro-phytoplankton, was tightly coupled with the meteo-climatic and hydrographical conditions. Over the short term, variations in the size structure and chlorophyll content of phytoplankton cells were related to changes in the physico-chemical environment, through changes in the availability of nutrients and light. Uncoupling between the dynamics of carbon biomass and chlorophyll resulted in chlorophyll to carbon ratios dependent on body size. The slope of the size dependence of chlorophyll content increased with increasing irradiance, reflecting different photoacclimation plasticity from pico-to micro-phytoplankton. The results have important implications for the productivity and the fate of biogenic carbon in this region, since the size dependence of photosynthetic rates is directly related to the size scaling of chlorophyll content.

  3. Application of advanced reservoir characterization, simulation, and production optimization strategies to maximize recovery in slope and basin clastic reservoirs, west Texas (Delaware Basin). Annual progress report, March 31, 1995--March 31, 1996

    Dutton, S.P.; Hovorka, S.D.; Cole, A.G.

    1996-08-01

    The objective of this Class III project is to demonstrate that detailed reservoir characterization of clastic reservoirs in basinal sandstones of the Delaware Mountain Group in the Delaware Basin of West Texas and New Mexico is a cost-effective way to recover more of the original oil in place by strategic infill-well placement and geologically based field development. Reservoirs in the Delaware Mountain Group have low producibility (average recovery <14 percent of the original oil in place) because of a high degree of vertical and lateral heterogeneity caused by depositional processes and post-depositional diagenetic modification. Detailed correlations of the Ramsey sandstone reservoirs in Geraldine Ford field suggest that lateral sandstone continuity is less than interpreted by previous studies. The degree of lateral heterogeneity in the reservoir sandstones suggests that they were deposited by eolian-derived turbidites. According to the eolian-derived turbidite model, sand dunes migrated across the exposed shelf to the shelf break during sea-level lowstands and provided well sorted sand for turbidity currents or grain flows into the deep basin.

  4. Hydrodynamic modeling of petroleum reservoirs using simulator MUFITS

    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

  5. A rationale for reservoir management economics

    Hickman, T.S.

    1995-01-01

    Significant economic benefits can be derived from the application f reservoir management. The key elements in economical reservoir management are the efficient use of available resources and optimization of reservoir exploitation through a multidisciplined approach. This paper describes various aspects of and approaches to reservoir management and provides case histories that support the findings

  6. How secure is subsurface CO2 storage? Controls on leakage in natural CO2 reservoirs

    Miocic, Johannes; Gilfillan, Stuart; McDermott, Christopher; Haszeldine, Stuart

    2014-05-01

    Carbon Capture and Storage (CCS) is the only industrial scale technology available to directly reduce carbon dioxide (CO2) emissions from fossil fuelled power plants and large industrial point sources to the atmosphere. The technology includes the capture of CO2 at the source and transport to subsurface storage sites, such as depleted hydrocarbon reservoirs or saline aquifers, where it is injected and stored for long periods of time. To have an impact on the greenhouse gas emissions it is crucial that there is no or only a very low amount of leakage of CO2 from the storage sites to shallow aquifers or the surface. CO2 occurs naturally in reservoirs in the subsurface and has often been stored for millions of years without any leakage incidents. However, in some cases CO2 migrates from the reservoir to the surface. Both leaking and non-leaking natural CO2 reservoirs offer insights into the long-term behaviour of CO2 in the subsurface and on the mechanisms that lead to either leakage or retention of CO2. Here we present the results of a study on leakage mechanisms of natural CO2 reservoirs worldwide. We compiled a global dataset of 49 well described natural CO2 reservoirs of which six are leaking CO2 to the surface, 40 retain CO2 in the subsurface and for three reservoirs the evidence is inconclusive. Likelihood of leakage of CO2 from a reservoir to the surface is governed by the state of CO2 (supercritical vs. gaseous) and the pressure in the reservoir and the direct overburden. Reservoirs with gaseous CO2 is more prone to leak CO2 than reservoirs with dense supercritical CO2. If the reservoir pressure is close to or higher than the least principal stress leakage is likely to occur while reservoirs with pressures close to hydrostatic pressure and below 1200 m depth do not leak. Additionally, a positive pressure gradient from the reservoir into the caprock averts leakage of CO2 into the caprock. Leakage of CO2 occurs in all cases along a fault zone, indicating that

  7. Calcium-Mediated Adhesion of Nanomaterials in Reservoir Fluids.

    Eichmann, Shannon L; Burnham, Nancy A

    2017-09-14

    Globally, a small percentage of oil is recovered from reservoirs using primary and secondary recovery mechanisms, and thus a major focus of the oil industry is toward developing new technologies to increase recovery. Many new technologies utilize surfactants, macromolecules, and even nanoparticles, which are difficult to deploy in harsh reservoir conditions and where failures cause material aggregation and sticking to rock surfaces. To combat these issues, typically material properties are adjusted, but recent studies show that adjusting the dispersing fluid chemistry could have significant impact on material survivability. Herein, the effect of injection fluid salinity and composition on nanomaterial fate is explored using atomic force microscopy (AFM). The results show that the calcium content in reservoir fluids affects the interactions of an AFM tip with a calcite surface, as surrogates for nanomaterials interacting with carbonate reservoir rock. The extreme force sensitivity of AFM provides the ability to elucidate small differences in adhesion at the pico-Newton (pN) level and provides direct information about material survivability. Increasing the calcium content mitigates adhesion at the pN-scale, a possible means to increase nanomaterial survivability in oil reservoirs or to control nanomaterial fate in other aqueous environments.

  8. Chemotrophic Ecosystem Beneath the Larsen Ice Shelf, Antarctica

    Leventer, A.; Domack, E.; Ishman, S.; Sylva, S.; Willmott, V.; Huber, B.; Padman, L.

    2005-12-01

    The first living chemotrophic ecosystem in the Southern Ocean was discovered in a region of the seafloor previously occupied by the Larsen-B Ice Shelf. A towed video survey documents an ecosystem characterized by a bottom-draping white mat that appears similar to mats of Begiattoa, hydrogen sulfide oxidizing bacteria, and bivalves, 20-30 cm large, similar to vesicomyid clams commonly found at cold seeps. The carbon source is unknown; three potential sources are hypothesized. First, thermogenically-produced methane may occur as the marine shales of this region are similar to hydrocarbon-bearing rocks to the north in Patagonia. The site occurs in an 850 m deep glacially eroded trough located along the contact between Mesozoic-Tertiary crystalline basement and Cretaceous-Tertiary marine rocks; decreased overburden could have induced upward fluid flow. Also possible is the dissociation of methane hydrates, a process that might have occurred as a result of warming oceanic bottom waters. This possibility will be discussed in light of the distribution of early diagenetic ikaite in the region. Third, the possibility of a biogenic methane source will be discussed. A microstratigraphic model for the features observed at the vent sites will be presented; the system is comprised of mud mounds with central vents and surrounding mud flow channels. A series of still image mosaics record the dynamic behavior of the system, which appears to demonstrate episodic venting. These images show the spatial relationship between more and less active sites, as reflected in the superposition of several episodes of mud flow activity and the formation of mud channels. In addition, detailed microscale features of the bathymetry of the site will be presented, placing the community within the context of glacial geomorphologic features. The Larsen-B Ice Shelf persisted through the entire Holocene, limiting carbon influx from a photosynthetic source. Tidal modeling of both pre and post breakup

  9. Shelf life prediction of canned fried-rice using accelerated shelf life testing (ASLT) arrhenius method

    Kurniadi, M.; Bintang, R.; Kusumaningrum, A.; Nursiwi, A.; Nurhikmat, A.; Susanto, A.; Angwar, M.; Triwiyono; Frediansyah, A.

    2017-12-01

    Research on shelf-life prediction of canned fried rice using Accelerated Shelf-life Test (ASLT) of Arrhenius model has been conducted. The aim of this research to predict shelf life of canned-fried rice products. Lethality value of 121°C for 15 and 20 minutes and Total Plate count methods are used to determine time and temperatures of sterilization process.Various storage temperatures of ASLT Arrhenius method were 35, 45 and 55°C during 35days. Rancidity is one of the derivation quality of canned fried rice. In this research, sample of canned fried rice is tested using rancidity value (TBA). TBA value was used as parameter which be measured once a week periodically. The use of can for fried rice without any chemical preservative is one of the advantage of the product, additionaly the use of physicalproperties such as temperature and pressure during its process can extend the shelf life and reduce the microbial contamination. The same research has never done before for fried rice as ready to eat meal. The result showed that the optimum conditions of sterilization process were 121°C,15 minutes with total plate count number of 9,3 × 101 CFU/ml. Lethality value of canned fried rice at 121°C,15 minutes was 3.63 minutes. The calculated Shelf-life of canned fried rice using Accelerated Shelf-life Test (ASLT) of Arrhenius method was 10.3 months.

  10. DELIVERABLE 1.2.4 CARBON AND OXYGEN ISOTOPIC ANALYSIS: BUG, CHEROKEE, AND PATTERSON CANYON FIELDS, SAN JUAN COUNTY, UTAH

    Eby, David E.; Chidsey, Thomas C. Jr; Kevin McClure; Morgan, Craig D.; Nelson, Stephen T.

    2003-01-01

    Over 400 million barrels (64 million m 3 ) of oil have been produced from the shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation in the Paradox Basin, Utah and Colorado. With the exception of the giant Greater Aneth field, the other 100 plus oil fields in the basin typically contain 2 to 10 million barrels (0.3-1.6 million m 3 ) of original oil in place. Most of these fields are characterized by high initial production rates followed by a very short productive life (primary), and hence premature abandonment. Only 15 to 25 percent of the original oil in place is recoverable during primary production from conventional vertical wells. An extensive and successful horizontal drilling program has been conducted in the giant Greater Aneth field. However, to date, only two horizontal wells have been drilled in small Ismay and Desert Creek fields. The results from these wells were disappointing due to poor understanding of the carbonate facies and diagenetic fabrics that create reservoir heterogeneity. These small fields, and similar fields in the basin, are at high risk of premature abandonment. At least 200 million barrels (31.8 million m 3 ) of oil will be left behind in these small fields because current development practices leave compartments of the heterogeneous reservoirs undrained. Through proper geological evaluation of the reservoirs, production may be increased by 20 to 50 percent through the drilling of low-cost single or multilateral horizontal legs from existing vertical development wells. In addition, horizontal drilling from existing wells minimizes surface disturbances and costs for field development, particularly in the environmentally sensitive areas of southeastern Utah and southwestern Colorado

  11. Improved Oil Recovery in Fluvial Dominated Deltaic Reservoirs of Kansas - Near-Term

    Green, Don W.; McCune, A.D.; Michnick, M.; Reynolds, R.; Walton, A.; Watney, L.; Willhite, G. Paul

    1999-01-01

    The objective of this project is to address waterflood problems of the type found in Morrow sandstone reservoirs in southwestern Kansas and in Cherokee Group reservoirs in southeastern Kansas. Two demonstration sites operated by different independent oil operators are involved in this project. The Stewart Field is located in Finney County, Kansas and is operated by PetroSantander, Inc. Te Nelson Lease is located in Allen County, Kansas, in the N.E. Savonburg Field and is operated by James E. Russell Petroleum, Inc. General topics to be addressed are (1) reservoir management and performance evaluation, (2) waterflood optimization, and (3) the demonstration of recovery processes involving off-the-shelf technologies which can be used to enhance waterflood recovery, increase reserves, and reduce the abandonment rate of these reservoir types. In the Stewart Project, the reservoir management portion of the project conducted during Budget Period 1 involved performance evaluation. This included (1) reservoir characterization and the development of a reservoir database, (2) volumetric analysis to evaluate production performance, (3) reservoir modeling, (4) laboratory work, (5) identification of operational problems, (6) identification of unrecovered mobile oil and estimation of recovery factors, and (7) Identification of the most efficient and economical recovery process. To accomplish these objectives the initial budget period was subdivided into three major tasks. The tasks were (1) geological and engineering analysis, (2) laboratory testing, and (3) unitization. Due to the presence of different operators within the field, it was necessary to unitize the field in order to demonstrate a field-wide improved recovery process. This work was completed and the project moved into Budget Period 2

  12. Outlet Glacier-Ice Shelf-Ocean Interactions: Is the Tail Wagging the Dog?

    Parizek, B. R.; Walker, R. T.; Rinehart, S. K.

    2009-12-01

    While the massive interior regions of the Antarctic and Greenland Ice Sheets are presently ``resting quietly", the lower elevations of many outlet glaciers are experiencing dramatic adjustments due to changes in ice dynamics and/or surface mass balance. Oceanic and/or atmospheric forcing in these marginal regions often leads to mass deficits for entire outlet basins. Therefore, coupling the wagging tail of ice-ocean interactions with the vast ice-sheet reservoirs is imperative for accurate assessments of future sea-level rise. To study ice-ocean dynamic processes, we couple an ocean-plume model that simulates ice-shelf basal melting rates based on temperature and salinity profiles combined with plume dynamics associated with the geometry of the ice-shelf cavity (following Jenkins, 1991 and Holland and Jenkins, 1999) with a two-dimensional, isothermal model of outlet glacier-ice shelf flow (as used in Alley et al., 2007; Walker et al., 2008; Parizek et al., in review). Depending on the assigned temperature and salinity profiles, the ocean model can simulate both water-mass end-members: either cold High Salinity Shelf Water (HSSW) or relatively warm Circumpolar Deep Water (CDW), as well as between-member conditions. Notably, the coupled system exhibits sensitivity to the initial conditions. In particular, melting concentrated near the grounding line has the greatest effect in forcing grounding-line retreat. Retreat is further enhanced by a positive feedback between the ocean and ice, as the focused melt near the grounding line leads to an increase in the local slope of the basal ice, thereby enhancing buoyancy-driven plume flow and subsequent melt rates.

  13. Reservoir attributes of a hydrocarbon-prone sandstone complex: case of the Pab Formation (Late Cretaceous) of Southwest Pakistan

    Umar, Muhammad; Khan, Abdul Salam; Kelling, Gilbert

    2016-01-01

    Links between the architectural elements of major sand bodies and reservoir attributes have been explored in a field study of the hydrocarbon-yielding Late Cretaceous Pab Formation of southwest Pakistan. The lithofacies and facies associations represented in the Pab Formation are the main...... determinants of its reservoir properties. Thus, thick, vertically connected and laterally continuous sand packets have moderate-to-high mean porosities (10–13 %) in fluviodeltaic, shoreface, shelf delta, submarine channel, and fan-lobe facies associations while deeper shelf and basin floor sand bodies yield...... significantly lower porosities (4–6 %). Overall, in the Pab arenites, porosity values increase with increasing grain size and better sorting. The varying sand-shale ratios encountered in different sectors of the Pab outcrop are also petrophysically important: Sequences displaying high ratios yield higher bulk...

  14. Reservoir effects in a Stone Age fjord on Lolland, Denmark

    Philippsen, Bente

    2018-01-01

    to be known for accurate radiocarbon dating of samples with possible aquatic carbon sources, such as human bones or food residues on pottery. Therefore, this paper attempts at calculating the local reservoir effect for the study area. I will discuss the possibilities and limitations when analysing radiocarbon...... for building chronologies and for reconstructing the environment of the Stone Age fjord. Finally, I will discuss the pitfalls and uncertainties associated with radiocarbon dates for sea level reconstruction....

  15. Late Jurassic – early Cretaceous inversion of rift structures, and linkage of petroleum system elements across post-rift unconformity, U.S. Chukchi Shelf, arctic Alaska

    Houseknecht, David W.; Connors, Christopher D.

    2015-01-01

    Basin evolution of the U.S. Chukchi shelf involved multiple phases, including Late Devonian–Permian rifting, Permian–Early Jurassic sagging, Late Jurassic–Neocomian inversion, and Cretaceous–Cenozoic foreland-basin development. The focus of ongoing exploration is a petroleum system that includes sag-phase source rocks; inversion-phase reservoir rocks; structure spanning the rift, sag, and inversion phases; and hydrocarbon generation during the foreland-basin phase.

  16. Cold-seep carbonates of the middle and lower continental slope, northern Gulf of Mexico

    Roberts, Harry H.; Feng, Dong; Joye, Samantha B.

    2010-11-01

    Authigenic carbonates from cold seeps on the middle and lower continental slope of the northern Gulf of Mexico (GOM) exhibit a wide range of mineralogical and stable isotopic compositions. These carbonates consist of concretions and nodules in surface sediments, hardgrounds of crusts and isolated slabs, and mounded buildups of blocks and slabs of up to over 10 meters in relief above the surrounding seafloor. Mineralogically, the carbonates are dominated by high-Mg calcite (HMC) and aragonite. However, low levels (oil, seawater CO2, and 13C-enriched residual CO2 from methanogenesis. A similarly large variability in δ18O values (2.5 to 6.7‰ PDB) demonstrates the geochemical complexity of the slope, with some samples pointing toward an 18O-enriched oxygen source that is possibly related to advection of 18O-enriched formation water and/or to the decomposition of gas hydrate. A considerable range of mineralogical and isotopic variations in cold-seep carbonate composition was noted even within individual study sites. However, common trends occur across multiple geographic areas. This situation suggests that local controls on fluid and gas flux, types of seep hydrocarbons, the presence or absence of gas hydrate in the near-surface sediment, and chemosynthetic communities, as well as the temporal evolution of the local hydrocarbon reservoir, all may play a part in determining carbonate mineralogy and isotope geochemistry. The carbon isotope data clearly indicate that between-site variation is greater than within-site variation. Seep carbonates formed on the middle and lower continental slope of the GOM do not appear to be substantially different from those found on the upper slope (<1000-m water depth). The highly variable fluids and gases that leave their geochemical imprints on seep carbonate of the middle and lower continental slope are similar to their outer shelf and upper slope counterparts.

  17. [Summer Greenhouse Gases Exchange Flux Across Water-air Interface in Three Water Reservoirs Located in Different Geologic Setting in Guangxi, China].

    Li, Jian-hong; Pu, Jun-bing; Sun, Ping-an; Yuan, Dao-xian; Liu, Wen; Zhang, Tao; Mo, Xue

    2015-11-01

    Due to special hydrogeochemical characteristics of calcium-rich, alkaline and DIC-rich ( dissolved inorganic carbon) environment controlled by the weathering products from carbonate rock, the exchange characteristics, processes and controlling factors of greenhouse gas (CO2 and CH4) across water-air interface in karst water reservoir show obvious differences from those of non-karst water reservoir. Three water reservoirs (Dalongdong reservoir-karst reservoir, Wulixia reservoir--semi karst reservoir, Si'anjiang reservoir-non-karst reservoir) located in different geologic setting in Guangxi Zhuang Autonomous Region, China were chosen to reveal characteristics and controlling factors of greenhouse gas exchange flux across water-air interface. Two common approaches, floating chamber (FC) and thin boundary layer models (TBL), were employed to research and contrast greenhouse gas exchange flux across water-air interface from three reservoirs. The results showed that: (1) surface-layer water in reservoir area and discharging water under dam in Dalongdong water reservoir were the source of atmospheric CO2 and CH4. Surface-layer water in reservoir area in Wulixia water reservoir was the sink of atmospheric CO2 and the source of atmospheric CH4, while discharging water under dam was the source of atmospheric CO2 and CH4. Surface-layer water in Si'anjiang water reservoir was the sink of atmospheric CO2 and source of atmospheric CH4. (2) CO2 and CH4 effluxes in discharging water under dam were much more than those in surface-layer water in reservoir area regardless of karst reservoir or non karst reservoir. Accordingly, more attention should be paid to the CO2 and CH4 emission from discharging water under dam. (3) In the absence of submerged soil organic matters and plants, the difference of CH4 effluxes between karst groundwater-fed reservoir ( Dalongdong water reservoir) and non-karst area ( Wulixia water reservoir and Si'anjiang water reservoir) was less. However, CO2

  18. Microgreens: Production, shelf life, and bioactive components.

    Mir, Shabir Ahmad; Shah, Manzoor Ahmad; Mir, Mohammad Maqbool

    2017-08-13

    Microgreens are emerging specialty food products which are gaining popularity and increased attention nowadays. They are young and tender cotyledonary leafy greens that are found in a pleasing palette of colors, textures, and flavors. Microgreens are a new class of edible vegetables harvested when first leaves have fully expanded and before true leaves have emerged. They are gaining popularity as a new culinary ingredient. They are used to enhance salads or as edible garnishes to embellish a wide variety of other dishes. Common microgreens are grown mainly from mustard, cabbage, radish, buckwheat, lettuce, spinach, etc. The consumption of microgreens has nowadays increased due to higher concentrations of bioactive components such as vitamins, minerals, and antioxidants than mature greens, which are important for human health. However, they typically have a short shelf life due to rapid product deterioration. This review aimed to evaluate the postharvest quality, potential bioactive compounds, and shelf life of microgreens for proper management of this specialty produce.

  19. Cloud computing and Reservoir project

    Beco, S.; Maraschini, A.; Pacini, F.; Biran, O.

    2009-01-01

    The support for complex services delivery is becoming a key point in current internet technology. Current trends in internet applications are characterized by on demand delivery of ever growing amounts of content. The future internet of services will have to deliver content intensive applications to users with quality of service and security guarantees. This paper describes the Reservoir project and the challenge of a reliable and effective delivery of services as utilities in a commercial scenario. It starts by analyzing the needs of a future infrastructure provider and introducing the key concept of a service oriented architecture that combines virtualisation-aware grid with grid-aware virtualisation, while being driven by business service management. This article will then focus on the benefits and the innovations derived from the Reservoir approach. Eventually, a high level view of Reservoir general architecture is illustrated.

  20. Multilevel techniques for Reservoir Simulation

    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...

  1. Geologic assessment of undiscovered oil and gas resources—Lower Cretaceous Albian to Upper Cretaceous Cenomanian carbonate rocks of the Fredericksburg and Washita Groups, United States Gulf of Mexico Coastal Plain and State Waters

    Swanson, Sharon M.; Enomoto, Catherine B.; Dennen, Kristin O.; Valentine, Brett J.; Cahan, Steven M.

    2017-02-10

    In 2010, the U.S. Geological Survey (USGS) assessed Lower Cretaceous Albian to Upper Cretaceous Cenomanian carbonate rocks of the Fredericksburg and Washita Groups and their equivalent units for technically recoverable, undiscovered hydrocarbon resources underlying onshore lands and State Waters of the Gulf Coast region of the United States. This assessment was based on a geologic model that incorporates the Upper Jurassic-Cretaceous-Tertiary Composite Total Petroleum System (TPS) of the Gulf of Mexico basin; the TPS was defined previously by the USGS assessment team in the assessment of undiscovered hydrocarbon resources in Tertiary strata of the Gulf Coast region in 2007. One conventional assessment unit (AU), which extends from south Texas to the Florida panhandle, was defined: the Fredericksburg-Buda Carbonate Platform-Reef Gas and Oil AU. The assessed stratigraphic interval includes the Edwards Limestone of the Fredericksburg Group and the Georgetown and Buda Limestones of the Washita Group. The following factors were evaluated to define the AU and estimate oil and gas resources: potential source rocks, hydrocarbon migration, reservoir porosity and permeability, traps and seals, structural features, paleoenvironments (back-reef lagoon, reef, and fore-reef environments), and the potential for water washing of hydrocarbons near outcrop areas.In Texas and Louisiana, the downdip boundary of the AU was defined as a line that extends 10 miles downdip of the Lower Cretaceous shelf margin to include potential reef-talus hydrocarbon reservoirs. In Mississippi, Alabama, and the panhandle area of Florida, where the Lower Cretaceous shelf margin extends offshore, the downdip boundary was defined by the offshore boundary of State Waters. Updip boundaries of the AU were drawn based on the updip extent of carbonate rocks within the assessed interval, the presence of basin-margin fault zones, and the presence of producing wells. Other factors evaluated were the middle

  2. Relationships between Charpy impact shelf energies and upper shelf Ksub(IC) values for reactor pressure vessel steels

    Witt, F.J.

    1983-01-01

    Charpy shelf data and lower bound estimates of Ksub(IC) shelf data for the same steels and test temperatures are given. Included are some typical reactor pressure vessel steels as well as some less tough or degraded steels. The data were evaluated with shelf estimates of Ksub(IC) up to and exceeding 550 MPa√m. It is shown that the high shelf fracture toughness representative of tough reactor pressure vessel steels may be obtained from a knowledge of the Charpy shelf energies. The toughness transition may be obtained either by testing small fracture toughness specimens or by Charpy energy indexing. (U.K.)

  3. Physical and nutrient data collected from CTD and bottle casts from the R/V HERMANO GINES from the continental shelf of Venezuela in the Caribbean Sea in support of the project: Carbon Retention in a Colored Ocean (CARIACO) from 16 March 2006 to 06 March 2007 (NODC Accession 0014920)

    National Oceanic and Atmospheric Administration, Department of Commerce — CTD and bottle data were collected from the R/V HERMANO GINES in the Caribbean Sea on the continental shelf of Venezuela from 16 March 2006 to 06 March 2007. Data...

  4. Ross Ice Shelf, Antarctic Ice and Clouds

    1991-01-01

    In this view of Antarctic ice and clouds, (56.5S, 152.0W), the Ross Ice Shelf of Antarctica is almost totally clear, showing stress cracks in the ice surface caused by wind and tidal drift. Clouds on the eastern edge of the picture are associated with an Antarctic cyclone. Winds stirred up these storms have been known to reach hurricane force.

  5. Regional geochemical baselines for Portuguese shelf sediments

    Mil-Homens, M.; Stevens, R.L.; Cato, I.; Abrantes, F.

    2007-01-01

    Metal concentrations (Al, Cr, Cu, Ni, Pb and Zn) from the DGM-INETI archive data set have been examined for sediments collected during the 1970s from 267 sites on the Portuguese shelf. Due to the differences in the oceanographic and sedimentological settings between western and Algarve coasts, the archive data set is split in two segments. For both shelf segments, regional geochemical baselines (RGB) are defined using aluminium as a reference element. Seabed samples recovered in 2002 from four distinct areas of the Portuguese shelf are superimposed on these models to identify and compare possible metal enrichments relative to the natural distribution. Metal enrichments associated with anthropogenic influences are identified in three samples collected nearby the Tejo River and are characterised by the highest enrichment factors (EF; EF Pb Zn < 4). EF values close to 1 suggest a largely natural origin for metal distributions in sediments from the other areas included in the study. - Background metal concentrations and their natural variability must be established before assessing anthropogenic impacts

  6. Distinguishing between old and modern permafrost sources in the northeast Siberian land-shelf system with compound-specific δ2H analysis

    Vonk, Jorien E.; Tesi, Tommaso; Bröder, Lisa; Holmstrand, Henry; Hugelius, Gustaf; Andersson, August; Dudarev, Oleg; Semiletov, Igor; Gustafsson, Örjan

    2017-08-01

    Pleistocene ice complex permafrost deposits contain roughly a quarter of the organic carbon (OC) stored in permafrost (PF) terrain. When permafrost thaws, its OC is remobilized into the (aquatic) environment where it is available for degradation, transport or burial. Aquatic or coastal environments contain sedimentary reservoirs that can serve as archives of past climatic change. As permafrost thaw is increasing throughout the Arctic, these reservoirs are important locations to assess the fate of remobilized permafrost OC.We here present compound-specific deuterium (δ2H) analysis on leaf waxes as a tool to distinguish between OC released from thawing Pleistocene permafrost (ice complex deposits; ICD) and from thawing Holocene permafrost (from near-surface soils). Bulk geochemistry (%OC; δ13C; %total nitrogen, TN) was analyzed as well as the concentrations and δ2H signatures of long-chain n-alkanes (C21 to C33) and mid- to long-chain n-alkanoic acids (C16 to C30) extracted from both ICD-PF samples (n = 9) and modern vegetation and O-horizon (topsoil-PF) samples (n = 9) from across the northeast Siberian Arctic. Results show that these topsoil-PF samples have higher %OC, higher OC / TN values and more depleted δ13C-OC values than ICD-PF samples, suggesting that these former samples trace a fresher soil and/or vegetation source. Whereas the two investigated sources differ on the bulk geochemical level, they are, however, virtually indistinguishable when using leaf wax concentrations and ratios. However, on the molecular isotope level, leaf wax biomarker δ2H values are statistically different between topsoil PF and ICD PF. For example, the mean δ2H value of C29 n-alkane was -246 ± 13 ‰ (mean ± SD) for topsoil PF and -280 ± 12 ‰ for ICD PF. With a dynamic isotopic range (difference between two sources) of 34 to 50 ‰; the isotopic fingerprints of individual, abundant, biomarker molecules from leaf waxes can thus serve as endmembers to distinguish between

  7. Sedimentological and Geomorphological Effects of Reservoir Flushing: The Cachi Reservoir, Costa Rica, 1996

    Brandt, Anders; Swenning, Joar

    1999-01-01

    Physical geography, hydrology, geomorphology, sediment transport, erosion, sedimentation, dams, reservoirs......Physical geography, hydrology, geomorphology, sediment transport, erosion, sedimentation, dams, reservoirs...

  8. Improved prediction of reservoir behavior through integration of quantitative geological and petrophysical data

    Auman, J. B.; Davies, D. K.; Vessell, R. K.

    1997-08-01

    Methodology that promises improved reservoir characterization and prediction of permeability, production and injection behavior during primary and enhanced recovery operations was demonstrated. The method is based on identifying intervals of unique pore geometry by a combination of image analysis techniques and traditional petrophysical measurements to calculate rock type and estimate permeability and saturation. Results from a complex carbonate and sandstone reservoir were presented as illustrative examples of the versatility and high level of accuracy of this method in predicting reservoir quality. 16 refs., 5 tabs., 14 figs.

  9. Modeling surface energy fluxes and thermal dynamics of a seasonally ice-covered hydroelectric reservoir.

    Wang, Weifeng; Roulet, Nigel T; Strachan, Ian B; Tremblay, Alain

    2016-04-15

    The thermal dynamics of human created northern reservoirs (e.g., water temperatures and ice cover dynamics) influence carbon processing and air-water gas exchange. Here, we developed a pr