Download or read book Modeling Density Effects in CO2 Injection in Oil Reservoirs and a Case Study of CO2 Sequestration in a Qatari Saline Aquifer written by Tausif Khizar Ahmed and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: CO2 injection has been used to improve oil recovery for several decades. In recent years, CO2 injection has become even more attractive because of a dual effect; injection in the subsurface 1) allows reduction of CO2 concentration in the atmosphere to reduce global warming, and 2) improves the oil recovery. In this study, the density effect from CO2 dissolution in modeling of CO2 injection is examined. A method to model the increase in oil density with CO2 dissolution using the Peng-Robinson equation of state and the Pedersen viscosity correlation is presented. This method is applied to model the observed increase in oil density with CO2 dissolution in a West Texas crude oil. Compositional simulation of CO2 injection was performed in a 2D vertical cross section and a 3D reservoir with the density effect. The results show that the density increase from CO2 dissolution may have a drastic effect on CO2 flow path and recovery performance. One main conclusion from this work is that there is a need to have accurate density data for CO2/oil mixtures at different CO2 concentrations to ensure successful CO2 injection projects. While CO2 enhanced oil recovery (EOR) is part of the solution, saline aquifers have the largest potential for CO2 sequestration. A literature review of the CO2 sequestration in saline aquifers is performed. The dominant trapping mechanisms and transport processes and the methods used to model them are discussed in detail. The Aruma aquifer, a shallow saline aquifer in southwest Qatar is used as a case study for CO2 sequestration. A compositional simulation model is prepared for the Aruma aquifer using the available log data and flow test data. It was found that the grid size is a key parameter in modeling CO2 sequestration accurately. It affects the propagation of the CO2 plume and amount of CO2 in brine.

Download or read book Modeling CO2 Sequestration in Saline Aquifer and Depleted Oil Reservoir To Evaluate Regional CO2 Sequestration Potential of Ozark Plateau Aquifer System South Central Kansas written by and published by . This book was released on 2014 with total page 1000 pages. Available in PDF, EPUB and Kindle. Book excerpt: 1. Drilled, cored, and logged three wells to the basement and collecting more than 2,700 ft of conventional core; obtained 20 mi2 of multicomponent 3D seismic imaging and merged and reprocessed more than 125 mi2 of existing 3D seismic data for use in modeling CO2- EOR oil recovery and CO2 storage in five oil fields in southern Kansas. 2. Determined the technical feasibility of injecting and sequestering CO2 in a set of four depleted oil reservoirs in the Cutter, Pleasant Prairie South, Eubank, and Shuck fields in southwest Kansas; of concurrently recovering oil from those fields; and of quantifying the volumes of CO2 sequestered and oil recovered during the process. 3. Formed a consortium of six oil operating companies, five of which own and operate the four fields. The consortium became part of the Southwest Kansas CO2-EOR Initiative for the purpose of sharing data, knowledge, and interest in understanding the potential for CO2-EOR in Kansas. 4. Built a regional well database covering 30,000 mi2 and containing stratigraphic tops from ~90,000 wells; correlated 30 major stratigraphic horizons; digitized key wells, including wireline logs and sample logs; and analyzed more than 3,000 drill stem tests to establish that fluid levels in deep aquifers below the Permian evaporites are not connected to the surface and therefore pressures are not hydrostatic. Connectivity with the surface aquifers is lacking because shale aquitards and impermeable evaporite layers consist of both halite and anhydrite. 5. Developed extensive web applications and an interactive mapping system that do the following: a. Facilitate access to a wide array of data obtained in the study, including core descriptions and analyses, sample logs, digital (LAS) well logs, seismic data, gravity and magnetics maps, structural and stratigraphic maps, inferred fault traces, earthquakes, Class I and II disposal wells, and surface lineaments. b. Provide real-time analysis of the project dataset, including automated integration and viewing of well logs, core, core analyses, brine chemistry, and stratigraphy using the Java Profile app. A cross-section app allows for the display of log data for up to four wells at a time. 6. Integrated interpretations from the project's interactive web-based mapping system to gain insights to aid in assessing the efficacy of geologic CO2 storage in Kansas and insights toward understanding recent seismicity to aid in evaluating induced vs. naturally occurring earthquakes. 7. Developed a digital type-log system, including web-based software to modify and refine stratigraphic nomenclature to provide stakeholders a common means for communication about the subsurface. 8. Contracted use of a nuclear magnetic resonance (NMR) log and ran it slowly to capture response and characterize larger pores common for carbonate reservoirs. Used NMR to extend core analyses to apply permeability, relative permeability to CO2, and capillary pressure to the major rock types, each uniquely expressed as a reservoir quality index (RQI), present in the Mississippian and Arbuckle rocks. 9. Characterized and evaluated the possible role of microbes in dense brines. Used microbes to compliment H/O stable isotopes to fingerprint brine systems. Used perforation/swabbing to obtain samples from multiple hydrostratigraphic units and confirmed equivalent results using less expensive drill stem tests (DST). 10. Used an integrated approach from whole core, logs, tests, and seismic to verify and quantify properties of vuggy, brecciated, and fractured carbonate intervals. 11. Used complex geocellular static and dynamic models to evaluate regional storage capacity using large parallel processing. 12. Carbonates are complex reservoirs and CO2-EOR needs to move to the next generation to increase effectiveness of CO2 and efficiency and safety of the inj ...

Download or read book Data Driven Analytics for the Geological Storage of CO2 written by Shahab Mohaghegh and published by CRC Press. This book was released on 2018-05-20 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data-driven analytics is enjoying unprecedented popularity among oil and gas professionals. Many reservoir engineering problems associated with geological storage of CO2 require the development of numerical reservoir simulation models. This book is the first to examine the contribution of artificial intelligence and machine learning in data-driven analytics of fluid flow in porous environments, including saline aquifers and depleted gas and oil reservoirs. Drawing from actual case studies, this book demonstrates how smart proxy models can be developed for complex numerical reservoir simulation models. Smart proxy incorporates pattern recognition capabilities of artificial intelligence and machine learning to build smart models that learn the intricacies of physical, mechanical and chemical interactions using precise numerical simulations. This ground breaking technology makes it possible and practical to use high fidelity, complex numerical reservoir simulation models in the design, analysis and optimization of carbon storage in geological formations projects.

Download or read book Understanding the Plume Dynamics and Risk Associated with CO2 Injection in Deep Saline Aquifers written by Abhishek Kumar Gupta and published by . This book was released on 2011 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geological sequestration of CO2 in deep saline reservoirs is one of the ways to reduce its continuous emission into the atmosphere to mitigate the greenhouse effect. The effectiveness of any CO2 sequestration operation depends on pore volume and the sequestration efficiency of the reservoir. Sequestration efficiency is defined here as the maximum storage with minimum risk of leakage to the overlying formations or to the surface. This can be characterized using three risk parameters i) the time the plume takes to reach the top seal; ii) maximum lateral extent of the plume and iii) the percentage of mobile CO2 present at any time. The selection among prospective saline reservoirs can be expedited by developing some semi-analytical correlations for these risk parameters which can be used in place of reservoir simulation study for each and every saline reservoir. Such correlations can reduce the cost and time for commissioning a geological site for CO2 sequestration. To develop such correlations, a database has been created from a large number of compositional reservoir simulations for different elementary reservoir parameters including porosity, permeability, permeability anisotropy, reservoir depth, thickness, dip, perforation interval and constant pressure far boundary condition. This database is used to formulate different correlations that relate the sequestration efficiency to reservoir properties and operating conditions. The various elementary reservoir parameters are grouped together to generate different variants of gravity number used in the correlations. We update a previously reported correlation for time to hit the top seal and develop new correlations for other two parameters using the newly created database. A correlation for percentage of trapped CO2 is also developed using a previously created similar database. We find that normalizing all risk parameters with their respective characteristic values yields reasonable correlations with different variants of gravity number. All correlations confirm the physics behind plume movement in a reservoir. The correlations reproduce almost all simulation results within a factor of two, and this is adequate for rapid ranking or screening of prospective storage reservoirs. CO2 injection in saline reservoirs on the scale of tens of millions of tonnes may result in fracturing, fault activation and leakage of brine along conductive pathways. Critical contour of overpressure (CoP) is a convenient proxy to determine the risk associated with pressure buildup at different location and time in the reservoir. The location of this contour varies depending on the target aquifer properties (porosity, permeability etc.) and the geology (presence and conductivity of faults). The CoP location also depends on relative permeability, and we extend the three-region injection model to derive analytical expressions for a specific CoP as a function of time. We consider two boundary conditions at the aquifer drainage radius, constant pressure or an infinite aquifer. The model provides a quick tool for estimating pressure profiles. Such tools are valuable for screening and ranking sequestration targets. Relative permeability curves measured on samples from seven potential storage formations are used to illustrate the effect on the CoPs. In the case of a constant pressure boundary and constant rate injection scenario, the CoP for small overpressures is time-invariant and independent of relative permeability. Depending on the relative values of overall mobilities of two-phase region and of brine region, the risk due to a critical CoP which lies in the two-phase region can either increase or decrease with time. In contrast, the risk due to a CoP in the drying region always decreases with time. The assumption of constant pressure boundaries is optimistic in the sense that CoPs extend the least distance from the injection well. We extend the analytical model to infinite-acting aquifers to get a more widely applicable estimate of risk. An analytical expression for pressure profile is developed by adapting water influx models from traditional reservoir engineering to the "three-region" saturation distribution. For infinite-acting boundary condition, the CoP trends depend on same factors as in the constant pressure case, and also depend upon the rate of change of aquifer boundary pressure with time. Commercial reservoir simulators are used to verify the analytical model for the constant pressure boundary condition. The CoP trends from the analytical solution and simulation results show a good match. To achieve safe and secure CO2 storage in underground reservoirs several state and national government agencies are working to develop regulatory frameworks to estimate various risks associated with CO2 injection in saline aquifers. Certification Framework (CF), developed by Oldenburg et al (2007) is a similar kind of regulatory approach to certify the safety and effectiveness of geologic carbon sequestration sites. CF is a simple risk assessment approach for evaluating CO2 and brine leakage risk associated only with subsurface processes and excludes compression, transportation, and injection-well leakage risk. Certification framework is applied to several reservoirs in different geologic settings. These include In Salah CO2 storage project Krechba, Algeria, Aquistore CO2 storage project Saskatchewan, Canada and WESTCARB CO2 storage project, Solano County, California. Compositional reservoir simulations in CMG-GEM are performed for CO2 injection in each storage reservoir to predict pressure build up risk and CO2 leakage risk. CO2 leakage risk is also estimated using the catalog of pre-computed reservoir simulation results. Post combustion CO2 capture is required to restrict the continuous increase of carbon content in the atmosphere. Coal fired electricity generating stations are the dominant players contributing to the continuous emissions of CO2 into the atmosphere. U.S. government has planned to install post combustion CO2 capture facility in many coal fired power plants including W.A. Parish electricity generating station in south Texas. Installing a CO2 capture facility in a coal fired power plant increases the capital cost of installation and operating cost to regenerate the turbine solvent (steam or natural gas) to maintain the stripper power requirement. If a coal-fired power plant with CO2 capture is situated over a viable source for geothermal heat, it may be desirable to use this heat source in the stripper. Geothermal brine can be used to replace steam or natural gas which in turn reduces the operating cost of the CO2 capture facility. High temperature brine can be produced from the underground geothermal brine reservoir and can be injected back to the reservoir after the heat from the hot brine is extracted. This will maintain the reservoir pressure and provide a long-term supply of hot brine to the stripper. Simulations were performed to supply CO2 capture facility equivalent to 60 MWe electric unit to capture 90% of the incoming CO2 in WA Parish electricity generating station. A reservoir simulation study in CMG-GEM is performed to evaluate the feasibility to recycle the required geothermal brine for 30 years time. This pilot study is scaled up to 15 times of the original capacity to generate 900 MWe stripping system to capture CO2 at surface.

Download or read book MODELING OF CARBON DIOXIDE SEQUESTRATION IN A DEEP SALINE AQUIFER written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT MODELING OF CARBON DIOXIDE SEQUESTRATION IN A DEEP SALINE AQUIFER BAÞBUÐ, Baþar M.S., Department of Petroleum and Natural Gas Engineering Supervisor : Prof. Dr. Fevzi Gümrah July 2005, 245 pages CO2 is one of the hazardous greenhouse gases causing significant changes in the environment. The sequestering CO2 in a suitable geological medium can be a feasible method to avoid the negative effects of CO2 emissions in the atmosphere. CO2 sequestration is the capture of, separation, and long-term storage of CO2 in underground geological environments. A case study was simulated regarding the CO2 sequestration in a deep saline aquifer. The compositional numerical model (GEM) of the CMG software was used to study the ability of the selected aquifer to accept and retain the large quantities of injected CO2 at supercritical state for long periods of time (200 years). A field-scale model with two injectors and six water producers and a single-well aquifer model cases were studied. In a single-well aquifer model, the effects of parameters such as vertical to horizontal permeability ratio, aquifer pressure, injection rate, and salinity on the sequestration process were examined and the sensitivity analyses were performed after simulating the field-scale model. The supercritical CO2, one-state fluid which exhibits both gas and liquid-like properties, and gaseous CO2 were sequestered in the forms of free CO2 bubble, dissolved CO2 in brine and precipitated CO2 with calcite mineral in a deep saline aquifer. The isothermal condition was assumed during injection and sequestration processes. The change in porosity and permeability values that might have occurred due to mineralization and CO2 adsorption on rock were not considered in this study. Vertical to horizontal permeability ratio and initial pressure conditions were the most dominating parameters affecting the CO2 saturation in each layer of the aquifer whereas CO2 injection rate influenced CO2 saturation in middle and bot.

Download or read book A Compositional Reservoir Simulation Study to Evaluate Impacts of Captured CO2 Composition Miscibility and Injection Strategy on CO2 EOR and Sequestration in a Carbonate Oil Reservoir written by Abdulhamid Alsousy and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the global energy demand rises, concerns regarding the increasing carbon levels deepen. Pushing the international community to pour their time and resources into exploring all avenues that bear potential to aid the decarbonization efforts. The decarbonization efforts attempt to either reduce carbon dioxide emissions or to capture carbon dioxide from the atmosphere. The oil and gas industry’s role falls into the first category. Where captured CO2 is sequestered into geological stable formations as part of carbon capture, utilization, and storage (CCUS) or carbon capture and storage (CCS) projects. CCUS and CCS technologies hold the keys to decarbonization, possessing a large capacity capable of storing over 8000 GtCO2, utilizing oil and gas reservoirs, saline aquifers, and coal beds to discard CO2. In addition, the sequestration in geological structures is long-term, with minimal risk of reintroducing the stored gas back to the surface. This work investigates two scenarios, one in which the reservoir undergoes a tertiary production and another where the reservoir has reached the abandonment stage of its life cycle. The analyses are carried out by employing a historically matched numerical model of a real carbonate reservoir to explore CO2 storage implications on the reservoir’s performance (EOR) and the efficiency of the injected gas storage in the subsurface. For a holistic evaluation, the numerical model accounts for relative permeability hysteresis, phase trapping, geochemistry, and thermodynamics. Various analyses are conducted to establish the recommended gas blend injected, the importance of miscibility, and the manner of injection (WAG or gas flood). The results showcased how miscible injection outperforms immiscible in CO2-EOR and sequestration efficiency. Furthermore, gas flood is recommended over WAG, especially when recycling produced gases is possible to store larger volumes of carbon dioxide

Download or read book Investigation of Multiple Well Injections for Carbon Dioxide Sequestration in Aquifers written by Abhishek Joshi and published by . This book was released on 2014 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the amount of CO2 present in the atmospheres is increasing due to combustion emission, it is becoming more and more important to find ways to reduce greenhouse gas emissions. One of the ways to do that is through carbon sequestration. Saline formations (aquifers) provide viable destination for carbon sequestration. The storage potential in these reservoirs is estimated at several thousands of Giga Tonnes (Gt) of CO2. Even though the capacity is substantial, the process of filling this capacity has a lot of challenges. Injection of large volumes within short period of time increases the formation pressure (which should be below fracture pressure) very fast. For each particular reservoir, injection capacity should be identified based on which CO2 can be injected within a particular injection area and time. In order to achieve this, an in-depth sensitivity study needs to be done on the various reservoir parameters such as thickness, rock compressibility, permeability, porosity, reservoir temperature and pressure, aquifer fracture pressure, number and placement of injection's wells. The objective of my Master's thesis work is finding ways to increase the storage injection capacity based on reservoir parameters and optimizing the well placement by identifying and developing analytical and numerical tools to do so. The research also focuses on conducting a sensitivity analysis on these parameters in order to find out the optimal injection scenario to obtain the amount of maximum CO2 sequestration in a reservoir. This study can help in the CO2 sequestration capacity predictions and screening suitable reservoir based on technical and economic criteria. In order to derive the injection capacity of the reservoir based on the reservoir parameters, two analytical models of multiple well injections were studied: i) Single-phase (Brine injection in a brine reservoir and ii) Two phase model (CO2 injection in a brine reservoir). In both cases, the aim is to analyse the pressure build-up and the results are discussed in terms of comparison with numerical simulations. Although analytical modeling is less accurate (compare to numerical) and restricted to vertical well injection it allows large number of realizations for sensitivity analysis to find significant patterns of the process and reduces the number of numerical simulations needed at final stages of optimization. Analysis is done by considering infinite acting, homogenous, isotropic and isothermal reservoir condition. The Ei-function approximation method was used to simulate results on pressure profile across the reservoir. Once we have a validated model, we look into increasing the CO2 injection capacity of saline aquifers by applying the multiple wells injection strategy. This was done by looking at the well interferences based on superposition principle and mapping the pressure build-up profile in the reservoir. Various approaches were used to get maximum injection capacity.

Download or read book Petrophysical Modeling and Simulation Study of Geological CO2 Sequestration written by Xianhui Kong and published by . This book was released on 2014 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: Global warming and greenhouse gas (GHG) emissions have recently become the significant focus of engineering research. The geological sequestration of greenhouse gases such as carbon dioxide (CO2) is one approach that has been proposed to reduce the greenhouse gas emissions and slow down global warming. Geological sequestration involves the injection of produced CO2 into subsurface formations and trapping the gas through many geological mechanisms, such as structural trapping, capillary trapping, dissolution, and mineralization. While some progress in our understanding of fluid flow in porous media has been made, many petrophysical phenomena, such as multi-phase flow, capillarity, geochemical reactions, geomechanical effect, etc., that occur during geological CO2 sequestration remain inadequately studied and pose a challenge for continued study. It is critical to continue to research on these important issues. Numerical simulators are essential tools to develop a better understanding of the geologic characteristics of brine reservoirs and to build support for future CO2 storage projects. Modeling CO2 injection requires the implementation of multiphase flow model and an Equation of State (EOS) module to compute the dissolution of CO2 in brine and vice versa. In this study, we used the Integrated Parallel Accurate Reservoir Simulator (IPARS) developed at the Center for Subsurface Modeling at The University of Texas at Austin to model the injection process and storage of CO2 in saline aquifers. We developed and implemented new petrophysical models in IPARS, and applied these models to study the process of CO2 sequestration. The research presented in this dissertation is divided into three parts. The first part of the dissertation discusses petrophysical and computational models for the mechanical, geological, petrophysical phenomena occurring during CO2 injection and sequestration. The effectiveness of CO2 storage in saline aquifers is governed by the interplay of capillary, viscous, and buoyancy forces. Recent experimental data reveals the impact of pressure, temperature, and salinity on interfacial tension (IFT) between CO2 and brine. The dependence of CO2-brine relative permeability and capillary pressure on IFT is also clearly evident in published experimental results. Improved understanding of the mechanisms that control the migration and trapping of CO2 in the subsurface is crucial to design future storage projects for long-term, safe containment. We have developed numerical models for CO2 trapping and migration in aquifers, including a compositional flow model, a relative permeability model, a capillary model, an interfacial tension model, and others. The heterogeneities in porosity and permeability are also coupled to the petrophysical models. We have developed and implemented a general relative permeability model that combines the effects of pressure gradient, buoyancy, and capillary pressure in a compositional and parallel simulator. The significance of IFT variations on CO2 migration and trapping is assessed. The variation of residual saturation is modeled based on interfacial tension and trapping number, and a hysteretic trapping model is also presented. The second part of this dissertation is a model validation and sensitivity study using coreflood simulation data derived from laboratory study. The motivation of this study is to gain confidence in the results of the numerical simulator by validating the models and the numerical accuracies using laboratory and field pilot scale results. Published steady state, core-scale CO2/brine displacement results were selected as a reference basis for our numerical study. High-resolution compositional simulations of brine displacement with supercritical CO2 are presented using IPARS. A three-dimensional (3D) numerical model of the Berea sandstone core was constructed using heterogeneous permeability and porosity distributions based on geostatistical data. The measured capillary pressure curve was scaled using the Leverett J-function to include local heterogeneity in the sub-core scale. Simulation results indicate that accurate representation of capillary pressure at sub-core scales is critical. Water drying and the shift in relative permeability had a significant impact on the final CO2 distribution along the core. This study provided insights into the role of heterogeneity in the final CO2 distribution, where a slight variation in porosity gives rise to a large variation in the CO2 saturation distribution. The third part of this study is a simulation study using IPARS for Cranfield pilot CO2 sequestration field test, conducted by the Bureau of Economic Geology (BEG) at The University of Texas at Austin. In this CO2 sequestration project, a total of approximately 2.5 million tons supercritical CO2 was injected into a deep saline aquifer about ~10000 ft deep over 2 years, beginning December 1st 2009. In this chapter, we use the simulation capabilities of IPARS to numerically model the CO2 injection process in Cranfield. We conducted a corresponding history-matching study and got good agreement with field observation. Extensive sensitivity studies were also conducted for CO2 trapping, fluid phase behavior, relative permeability, wettability, gravity and buoyancy, and capillary effects on sequestration. Simulation results are consistent with the observed CO2 breakthrough time at the first observation well. Numerical results are also consistent with bottomhole injection flowing pressure for the first 350 days before the rate increase. The abnormal pressure response with rate increase on day 350 indicates possible geomechanical issues, which can be represented in simulation using an induced fracture near the injection well. The recorded injection well bottomhole pressure data were successfully matched after modeling the fracture in the simulation model. Results also illustrate the importance of using accurate trapping models to predict CO2 immobilization behavior. The impact of CO2/brine relative permeability curves and trapping model on bottom-hole injection pressure is also demonstrated.

Download or read book Experimental Design Applications for Modeling and Assessing Carbon Dioxide Sequestration in Saline Aquifers written by and published by . This book was released on 2014 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project was a computer modeling effort to couple reservoir simulation and ED/RSM using Sensitivity Analysis, Uncertainty Analysis, and Optimization Methods, to assess geologic, geochemical, geomechanical, and rock-fluid effects and factors on CO2 injectivity, capacity, and plume migration. The project objective was to develop proxy models to simplify the highly complex coupled geochemical and geomechanical models in the utilization and storage of CO2 in the subsurface. The goals were to investigate and prove the feasibility of the ED/RSM processes and engineering development, and bridge the gaps regarding the uncertainty and unknowns of the many geochemical and geomechanical interacting parameters in the development and operation of anthropogenic CO2 sequestration and storage sites. The bottleneck in this workflow is the high computational effort of reactive transport simulation models and large number of input variables to optimize with ED/RSM techniques. The project was not to develop the reactive transport, geomechanical, or ED/RSM software, but was to use what was commercially and/or publically available as a proof of concept to generate proxy or surrogate models. A detailed geologic and petrographic mineral assemblage and geologic structure of the doubly plunging anticline was defined using the USDOE RMOTC formations of interest data (e.g., Lower Sundance, Crow Mountain, Alcova Limestone, and Red Peak). The assemblage of 23 minerals was primarily developed from literature data and petrophysical (well log) analysis. The assemblage and structure was input into a commercial reactive transport simulator to predict the effects of CO2 injection and complex reactions with the reservoir rock. Significant impediments were encountered during the execution phase of the project. The only known commercial reactive transport simulator was incapable of simulating complex geochemistry modeled in this project. Significant effort and project funding was expended to determine the limitations of both the commercial simulator and the Lawrence Berkeley National Laboratory (LBNL) R & D simulator, TOUGHREACT available to the project. A simplified layer cake model approximating the volume of the RMOTC targeted reservoirs was defined with 1-3 minerals eventually modeled with limited success. Modeling reactive transport in porous media requires significant computational power. In this project, up to 24 processors were used to model a limited mineral set of 1-3 minerals. In addition, geomechanical aspects of injecting CO2 into closed, semi-open, and open systems in various well completion methods was simulated. Enhanced Oil Recovery (EOR) as a storage method was not modeled. A robust and stable simulation dataset or base case was developed and used to create a master dataset with embedded instructions for input to the ED/RSM software. Little success was achieved toward the objective of the project using the commercial simulator or the LBNL simulator versions available during the time of this project. Several hundred realizations were run with the commercial simulator and ED/RSM software, most having convergence problems and terminating prematurely. A proxy model for full field CO2 injection sequestration utilization and storage was not capable of being developed with software available for this project. Though the chemistry is reasonably known and understood, based on the amount of effort and huge computational time required, predicting CO2 sequestration storage capacity in geologic formations to within the program goals of ±30% proved unsuccessful.

Download or read book Reactive Transport Modeling of Geologic CO2 Sequestration in Saline Aquifers written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, we address a series of fundamental questions regarding the processes and effectiveness of geologic CO2 sequestration in saline aquifers. We begin with the broadest: what is the ultimate fate of CO2 injected into these environments? Once injected, it is immediately subject to two sets of competing processes: migration processes and sequestration processes. In terms of migration, the CO2 moves by volumetric displacement of formation waters, with which it is largely immiscible; by gravity segregation, which causes the immiscible CO2 plume to rise owing to its relatively low density; and by viscous fingering, owing to its relatively low viscosity. In terms of sequestration, some fraction of the rising plume will dissolve into formation waters (solubility trapping); some fraction may react with formation minerals to precipitate carbonates (mineral trapping); and the remaining portion eventually reaches the cap rock, where it migrates up-dip, potentially accumulating in local topographic highs (structural trapping). Although this concept of competing migration/sequestration processes is intuitively obvious, identifying those sub-processes that dominate the competition is by no means straightforward. Hence, at present there are large uncertainties associated with the ultimate fate of injected CO2 (Figure 1). Principal among these: can a typical shale cap rock provide a secure seal? Because gravity segregation will always keep the immiscible CO2 plume moving towards the surface, caprock integrity is the single most important variable influencing isolation security. An extremely thick shale cap rock exists at Sleipner (several 100 m); here, however, we examine the performance of a 25-m-thick cap, which is more representative of the general case. Although the cap rock represents the final barrier to vertical CO2 migration, what is the effect of intra-aquifer permeability structure? Because this structure directs the path of all CO2 migration processes within the target formation, it will effectively determine the spatial extent of plume-aquifer interaction, and thereby exert a controlling influence on all sequestration processes. Here, we consider three common settings: a homogeneous saline aquifer, one with inter-bedded laterally continuous shales (continuum representation of microfractured shales), and one with inter-bedded laterally discontinuous shales (discrete representation of lateral facies changes). For each configuration, we examine the unique character of immiscible CO2 migration paths, describe the dependent location, timing, and extent of associated solubility and mineral trapping, and detail the relative partitioning of injected CO2 among the immiscible plume, formation waters, and carbonate precipitates. While intra-aquifer permeability structure establishes the spatial framework of plume-aquifer interaction, the effectiveness of solubility and mineral trapping within this setting is largely determined by compositional characteristics of the aquifer and (if present) its inter-bedded shales. Here, we focus on Sleipner, where the saline aquifer consists of unconsolidated impure quartz sand saturated with a seawater-like aqueous phase, and there is strong evidence of thin interbedded shales. Based on our modeling results for this environment, we infer the effect of varying fluid composition from dilute to saline to brine, and the effect of varying sand and shale mineralogy within relevant limits. In addition, we describe those compositional characteristics required to maximize solubility and mineral trapping for a given permeability configuration. We also address the fundamental yet infrequently posed question: what happens when CO2 injection is terminated? Hydrologic and geochemical evolution may be very different during the relatively brief ''prograde'' (active-injection) and subsequent long-term ''retrograde'' (postinjection) regimes of geologic sequestration. Most importantly, are prograde trapping mechanisms enhanced or reversed during the retrograde phase (which spans geologic time scales)? We will demonstrate that there are indeed significant differences between prograde and retrograde sequestration.

Download or read book Reservoir Simulation Studies for Coupled CO2 Sequestration and Enhanced Oil Recovery written by Yousef Ghomian and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Compositional reservoir simulation studies were performed to investigate the effect of uncertain reservoir parameters, flood design variables, and economic factors on coupled CO2 sequestration and EOR projects. Typical sandstone and carbonate reservoir properties were used to build generic reservoir models. A large number of simulations were needed to quantify the impact of all these factors and their corresponding uncertainties taking into account various combinations of the factors. The design of experiment method along with response surface methodology and Monte-Carlo simulations were utilized to maximize the information gained from each uncertainty analysis. The two objective functions were project profit in the form of $/bbl of oil produced and sequestered amount of CO2 in the reservoir. The optimized values for all objective functions predicted by design of experiment and the response surface method were found to be close to the values obtained by the simulation study, but with only a small fraction of the computational time. After the statistical analysis of the simulation results, the most to least influential factors for maximizing both profit and amount of stored CO2 are the produced gas oil ratio constraint, production and injection well types, and well spacing. For WAG injection scenarios, the Dykstra-Parsons coefficient and combinations of WAG ratio and slug size are important parameters. Also for a CO2 flood, no significant reduction of profit occurred when only the storage of CO2 was maximized. In terms of the economic parameters, it was demonstrated that the oil price dominates the CO2 EOR and storage. This study showed that sandstone reservoirs have higher probability of need for CO2i ncentives. In addition, higher CO2 credit is needed for WAG injection scenarios than continuous CO2 injection. As the second part of this study, scaling groups for miscible CO2 flooding in a three-dimensional oil reservoir were derived using inspectional analysis with special emphasis on the equations related to phase behavior. Some of these scaling groups were used to develop a new MMP correlation. This correlation was compared with published correlations using a wide range of reservoir fluids and found to give more accurate predictions of the MMP.

Download or read book Optimization of Multiple Wells in Carbon Sequestration written by Swathi Gangadharan and published by . This book was released on 2014 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: Injection of CO2 in saline aquifers is considered as one of the best strategies for the reduction of greenhouse gases. In order to select a potential saline aquifer storage site for carbon sequestration, many parameters are considered such as relative permeability, thickness, compressibility, porosity, salinity and well interference. These are significant because they affect the CO2 storage capacity of the reservoir. The one of the most important criteria to be considered during sequestration is the pressure profile inside the reservoir as the sequestered CO2 increases the pressure within the saline formation over time. In order to maintain the integrity of the reservoir, the reservoir pressure is always maintained below the fracture pressure. Thus, modeling of pressure profile is essential as it controls the maximum amount of CO2 which can be into the reservoir. There are various analytical and numerical models to determine the bottom-hole pressure for CO2 injection. The main objective of my thesis is to examine and identify the analytical approaches in modeling of pressure profile during CO2 injection. It includes single injection as well as multiple wells injection scenarios. The second case is much more important from practical point of view and applicability of analytical tools should be validated. Two models of injection/production are considered: (i) Single-phase (brine production from a brine reservoir) and (ii) Two phase model (CO2 injection in a brine reservoir). In both cases, we analyzed the pressure build-up and discussed the results in comparison with numerical simulations. We also present a sensitivity analysis of the reservoir parameters on CO2 sequestration. The second part of the thesis focuses on finding ways to increase the CO2 injection capacity of saline aquifers by using the technique of multiple wells injection strategy. Numerous test cases will be presented to optimize the well placement and number of wells to get the maximum sequestration. The thesis will look upon the different ways to maintain the reservoir pressure below fracture pressure such as optimization of injection wells, varying the flow-rates of injection wells and by placement of relief wells to produce brine from the reservoir.

Download or read book Experimental and Numarical Investigation of Carbon Dioxide Sequestration in Deep Saline Aquifers written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Started as an EOR technique to produce oil, injection of carbon dioxide which is essentially a greenhouse gas is becoming more and more important. Although there are a number of mathematical modeling studies, experimental studies are limited and most studies focus on injection into sandstone reservoirs as opposed to carbonate ones. This study presents the results of computerized tomography (CT) monitored laboratory experiments to characterize relevant chemical reactions associated with injection and storage of CO2 in carbonate formations. Porosity changes along the core plugs and the corresponding permeability changes are reported for varying CO2 injection rates, temperature and salt concentrations. CT monitored experiments are designed to model fast near well bore flow and slow reservoir flows. It was observed that either a permeability improvement or a permeability reduction can be obtained. The trend of change in rock properties is very case dependent because it is related to distribution of pores, brine composition and as well the thermodynamic conditions. As the salt concentration decreased the porosity and thus the permeability decrease was less pronounced. Calcite scaling is mainly influenced by orientation and horizontal flow resulted in larger calcite deposition compared to vertical flow. The duration of CO2 – rock contact and the amount of area contacted by CO2 seems to have a more pronounced effect compared to rate effect. The experiments were modeled using a multi-phase, non-isothermal commercial simulator where solution and deposition of calcite were considered by the means of chemical reactions. The calibrated model was then used to analyze field scale injections and to model the potential CO2 sequestration capacity of a hypothetical carbonate aquifer formation. It was observed that solubility and hydrodynamic storage of CO2 is larger compared to mineral trapping.

Download or read book Mathematical Modeling of Extended Interface During Gravity Drainage With Application to CO2 Sequestration written by Farshad Arfaei Malekzadeh and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Removal of CO2 directly from anthropogenic sources (capture) and its disposal in geological formations can take place for medium-term time periods (storage), or it can be permanent (sequestration), with the CO2 eventually becoming dissolved in the aqueous phase. The latter is the main subject of this dissertation. Carbon dioxide sequestration covers a wide range of strategies and alternatives. The main objective of CO2 sequestration alternatives is secure disposal of carbon in large amounts and for a lengthy time scale (typically 1000 years). Injection of CO2 into subsurface formations is generally considered as the main option for CO2 sequestration. Geological sequestration through injection covers a broad variety of target formations: disposal in depleted oil and gas reservoirs, trapping in oil reservoirs, replacing CH4 in coal bed methane recovery processes, trapping in deep aquifers, and salt cavern placement are the major CCS alternatives in geologic formations. In this thesis, hydrogeologic interaction between the injectant (CO2) and the host fluid (saline water) during injection is the main subject of the project. Because of the density and viscosity contrast of displacing and displaced fluids, the pattern of saturation progression is complicated. A set of semi-analytical solutions is developed for quick estimation of the position of isosats (contours of saturation) during primary injection in homogenous cases with simple geometry. All of the mathematical solutions are developed based on two assumptions; incompressible fluids and rocks and vertical equilibrium (capillary-gravity condition) for geometries with large aspect ratio (L ” H). First, a series of analytical solutions for primary drainage for a set of linear relative permeability functions is developed. The first analytical solution is based on the assumption of locally linearized Leverett-J functions, and by using the method of characteristics, a formulation for the isosats' geometry is obtained. A semi-analytical solution is then proposed for calculation of the position of isosats with linearized relative permeability functions and arbitrary capillary-saturation correlation. The analytical solution is extended to incorporate a specific form of nonlinearity of the relative permeability function. Nonlinear relative permeability functions are also incorporated in another semi-analytical solution, and the positions of the isosats for any arbitrary Leverett-J function and relative permeability functions are developed. Sequential gas-saline injection is also modeled in that chapter. For approximate verification of the analytical solutions, a FEM numerical model is developed and the results of the analytical solutions are compared with the numerical solutions. These new analytical solutions provide powerful tools for prediction of saturation distribution during injection in vertical and horizontal wells, as well as for carrying out stochastic assessments (Monte Carlo simulations) and parametric weight assessment. The domain of applications of the new solutions go far beyond the limited question of CO2 sequestration: they can be used for injection of any less viscous fluid into a reservoir, whether the fluid is lighter or denser than the host fluid (gas injection, water-alternating gas injection, water injection into viscous oil reservoirs, solvent injection).

Download or read book Simulation of CO2 Sequestration at Rock Spring Uplift Wyoming written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many geological, geochemical, geomechanical and hydrogeological factors control CO2 storage in subsurface. Among them heterogeneity in saline aquifer can seriously influence design of injection wells, CO2 injection rate, CO2 plume migration, storage capacity, and potential leakage and risk assessment. This study applies indicator geostatistics, transition probability and Markov chain model at the Rock Springs Uplift, Wyoming generating facies-based heterogeneous fields for porosity and permeability in target saline aquifer (Pennsylvanian Weber sandstone) and surrounding rocks (Phosphoria, Madison and cap-rock Chugwater). A multiphase flow simulator FEHM is then used to model injection of CO2 into the target saline aquifer involving field-scale heterogeneity. The results reveal that (1) CO2 injection rates in different injection wells significantly change with local permeability distributions; (2) brine production rates in different pumping wells are also significantly impacted by the spatial heterogeneity in permeability; (3) liquid pressure evolution during and after CO2 injection in saline aquifer varies greatly for different realizations of random permeability fields, and this has potential important effects on hydraulic fracturing of the reservoir rock, reactivation of pre-existing faults and the integrity of the cap-rock; (4) CO2 storage capacity estimate for Rock Springs Uplift is 6614 ± 256 Mt at 95% confidence interval, which is about 36% of previous estimate based on homogeneous and isotropic storage formation; (5) density profiles show that the density of injected CO2 below 3 km is close to that of the ambient brine with given geothermal gradient and brine concentration, which indicates CO2 plume can sink to the deep before reaching thermal equilibrium with brine. Finally, we present uncertainty analysis of CO2 leakage into overlying formations due to heterogeneity in both the target saline aquifer and surrounding formations. This uncertainty in leakage will be used to feed into risk assessment modeling.

Download or read book A Simulation Study of Injected CO2 Migration in the Faulted Reservoir written by Kyung Won Chang and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Confined Fluid Phase Behavior and CO2 Sequestration in Shale Reservoirs written by Yueliang Liu and published by Gulf Professional Publishing. This book was released on 2022-05-05 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Confined Fluid Phase Behavior and CO2 Sequestration in Shale Reservoirs delivers the calculation components to understand pore structure and absorption capacity involving unconventional reservoirs. Packed with experimental procedures, step-by-step instructions, and published data, the reference explains measurements for capillary pressure models, absorption behavior in double nano-pore systems, and the modeling of interfacial tension in C02/CH4/brine systems. Rounding out with conclusions and additional literature, this reference gives petroleum engineers and researchers the knowledge to maximize productivity in shale reservoirs. - Helps readers gain advanced understanding of methods of adsorption behavior in shale gas - Presents theories and calculations for measuring and computing by providing step-by-step instructions, including flash calculation for phase equilibrium - Includes advances in shale fluid behavior, along with well-structured experiments and flow charts