Download or read book Sensitivity Study of CO2 Storage Capacity in Brine Aquifers Withclosed Boundaries written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In large-scale geologic storage projects, the injected volumes of CO2 will displace huge volumes of native brine. If the designated storage formation is a closed system, e.g., a geologic unit that is compartmentalized by (almost) impermeable sealing units and/or sealing faults, the native brine cannot (easily) escape from the target reservoir. Thus the amount of supercritical CO2 that can be stored in such a system depends ultimately on how much pore space can be made available for the added fluid owing to the compressibility of the pore structure and the fluids. To evaluate storage capacity in such closed systems, we have conducted a modeling study simulating CO2 injection into idealized deep saline aquifers that have no (or limited) interaction with overlying, underlying, and/or adjacent units. Our focus is to evaluate the storage capacity of closed systems as a function of various reservoir parameters, hydraulic properties, compressibilities, depth, boundaries, etc. Accounting for multi-phase flow effects including dissolution of CO2 in numerical simulations, the goal is to develop simple analytical expressions that provide estimates for storage capacity and pressure buildup in such closed systems.

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 282 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 Large scale Impact of CO2 Storage in Deep Saline Aquifers written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Large volumes of CO2 captured from carbon emitters (such as coal-fired power plants) may be stored in deep saline aquifers as a means of mitigating climate change. Storing these additional fluids may cause pressure changes and displacement of native brines, affecting subsurface volumes that can be significantly larger than the CO2 plume itself. This study aimed at determining the three-dimensional region of influence during/after injection of CO2 and evaluating the possible implications for shallow groundwater resources, with particular focus on the effects of interlayer communication through low-permeability seals. To address these issues quantitatively, we conducted numerical simulations that provide a basic understanding of the large-scale flow and pressure conditions in response to industrial-scale CO2 injection into a laterally open saline aquifer. The model domain included an idealized multilayered groundwater system, with a sequence of aquifers and aquitards (sealing units) extending from the deep saline storage formation to the uppermost freshwater aquifer. Both the local CO2-brine flow around the single injection site and the single-phase water flow (with salinity changes) in the region away from the CO2 plume were simulated. Our simulation results indicate considerable pressure buildup in the storage formation more than 100 km away from the injection zone, whereas the lateral distance migration of brine is rather small. In the vertical direction, the pressure perturbation from CO2 storage may reach shallow groundwater resources only if the deep storage formation communicates with the shallow aquifers through sealing units of relatively high permeabilities (higher than 10 x 18 m2). Vertical brine migration through a sequence of layers into shallow groundwater bodies is extremely unlikely. Overall, large-scale pressure changes appear to be of more concern to groundwater resources than changes in water quality caused by the migration of displaced saline water.

Download or read book Sensitivity Analysis of Carbon Dioxide Storage in Saline Aquifers in the Presence of a Gas Cap written by Silvia Veronica Solano and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Deep brine-bearing formations contain a significant CO2 storage potential as they are usually permeable sandstones at depths in which pressure and temperature conditions assure supercritical state for the injected CO2. When injecting CO2 in a hydrocarbon-rich area, presence of a gas cap significantly impacts the CO2 plume behavior. This study focuses on the assessment of the CO2 plume properties in formations typical of the Gulf Coast area, under the presence of a gas cap and its consequences for long-term storage. The study is prompted by the presence of a large depleted gas cap at Cranfield, Mississippi where CO2 is being injected for long-term storage. Presence of the gas cap, even depleted, near the injection site provides an exceptional opportunity to investigate an area made of higher compressibility fluids and its impact on reservoir and operational parameters, particularly CO2 plume behavior. Enhanced gas recovery is not planned within this area. Considerable volumes of native brine are displaced when large amounts of CO2 are injected, and when this displacement occurs in a closed system, the amount of stored CO2 will depend solely on the additional pore space available owing to compressibility of the pore structure and fluids. As a result, presence of a gas cap is expected to impact plume characteristics, as well as operational conditions, because of its larger compressibility. A multi-parameter sensitivity analysis, based on a generic reservoir model, was performed to appreciate relevant factors to CO2 migration under the influence of the nearby gas cap. It was achieved using the compositional reservoir simulator CMG-GEM and allied modules. Main parameters taken into account for the sensitivity analysis included variation in gas cap properties such as: volume, gas composition and gas residual saturation. Additionally, other parameters have been included in this study such as reservoir dip, injector-gas-cap distance, injection pressure, plume asymmetry and horizontal centroid location. The CO2 plume extends farther as the gas cap volume increases and the distance to the gas cap decreases. Gas residual saturation conditions in the gas cap region are not expected to affect the maximum lateral plume extent as much as the existent volume of gas. The effect of gas cap composition in CO2 migration is dominated by pressure changes within the formation which subsequently affects the gas cap compressibility and in consequence the plume maximum lateral extent. For example, contamination of a methane-rich gas cap by injected CO2 has a strong effect on the plume maximum lateral extent due to compressibility changes. This, in turn, affects regulatory Area of Review, project technical risks, and economics. In another part of the study, a dimensional analysis was performed to identify and assess dominant forces relevant to CO2 plume distribution in the presence of a gas cap. Dimensionless groups were used to express the relationship between centroid location and the ratio of gravity and viscous forces given by the gravity number. Appropriate assessment of gas cap impact on CO2 plume distribution and on aquifer pressure build-up is fundamental for developing an accurate economic outlook as well as for taking into account regulatory constraints (including a monitoring plan addressing leakage risk and possible aquifer contamination).

Download or read book Time lapse Seismic Monitoring of CO2 Storage in Saline Aquifers written by Grace Cairns and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Geological Storage of CO2 written by Jan Martin Nordbotten and published by John Wiley & Sons. This book was released on 2011-10-24 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the large research effort in both public and commercial companies, no textbook has yet been written on this subject. This book aims to provide an overview to the topic of Carbon Capture and Storage (CSS), while at the same time focusing on the dominant processes and the mathematical and numerical methods that need to be employed in order to analyze the relevant systems. The book clearly states the carbon problem and the role of CCS and carbon storage. Thereafter, it provides an introduction to single phase and multi-phase flow in porous media, including some of the most common mathematical analysis and an overview of numerical methods for the equations. A considerable part of the book discusses the appropriate scales of modeling, and how to formulate consistent governing equations at these scales. The book also illustrates real world data sets and how the ideas in the book can be exploited through combinations of analytical and numerical approaches.

Download or read book Enhanced CO2 Storage in Confined Geologic Formations written by Roland Tenjoh Okwen and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Many geoscientists endorse Carbon Capture and Storage (CCS) as a potential strategy for mitigating emissions of greenhouse gases. Deep saline aquifers have been reported to have larger CO2 storage capacity than other formation types because of their availability worldwide and less competitive usage. This work proposes an analytical model for screening potential CO2 storage sites and investigates injection strategies that can be employed to enhance CO2 storage. The analytical model provides of estimates CO2 storage efficiency, formation pressure profiles, and CO2-brine interface location. The results from the analytical model were compared to those from a sophisticated and reliable numerical model (TOUGH2). The models showed excellent agreement when input conditions applied in both were similar. Results from sensitivity studies indicate that the agreement between the analytical model and TOUGH2 strongly depends on irreducible brine saturation, gravity and on the relationship between relative permeability and brine saturation. A series of numerical experiments have been conducted to study the pros and cons of different injection strategies for CO2 storage in confined saline aquifers. Vertical, horizontal, and joint vertical and horizontal injection wells were considered. Simulations results show that horizontal wells could be utilized to improve CO2 storage capacity and efficiency in confined aquifers under pressure-limited conditions with relative permeability ratios greater than or equal to 0:01. In addition, joint wells are more efficient than single vertical wells and less efficient than single horizontal wells for CO2 storage in anisotropic aquifers.

Download or read book Time lapse Seismic Monitoring of CO2 Storage in Saline Aquifers written by Grace Cairns and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sustainable Carbon Sequestration written by Oyewande Akinnikawe and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: CO2 sequestration is one of the proposed methods for reducing anthropogenic CO2 emissions to the atmosphere and therefore mitigating global climate change. Few studies on storing CO2 in an aquifer have been conducted on a regional scale. This study offers a conceptual approach to increasing the storage efficiency of CO2 injection in saline formations and investigates what an actual CO2 storage project might entail using field data for the Woodbine aquifer in East Texas. The study considers three aquifer management strategies for injecting CO2 emissions from nearby coal-fired power plants into the Woodbine aquifer. The aquifer management strategies studied are bulk CO2 injection, and two CO2-brine displacement strategies. A conceptual model performed with homogeneous and average reservoir properties reveals that bulk injection of CO2 pressurizes the aquifer, has a storage efficiency of 0.46% and can only last for 20 years without risk of fracturing the CO2 injection wells. The CO2-brine displacement strategy can continue injecting CO2 for as many as 240 years until CO2 begins to break through in the production wells. This offers 12 times greater CO2 storage efficiency than the bulk injection strategy. A full field simulation with a geological model based on existing aquifer data validates the storage capacity claims made by the conceptual model. A key feature in the geological model is the Mexia-Talco fault system that serves as a likely boundary between the saline aquifer region suitable for CO2 storage and an updip fresh water region. Simulation results show that CO2 does not leak into the fresh water region of the iv aquifer after 1000 years of monitoring if the faults have zero transmissibility, but a negligible volume of brine eventually gets through the mostly sealing fault system as pressure across the faults slowly equilibrates during the monitoring period. However, for fault transmissibilities of 0.1 and 1, both brine and CO2 leak into the fresh water aquifer in increasing amounts for both bulk injection and CO2-brine displacement strategies. In addition, brine production wells draw some fresh water into the saline aquifer if the Mexia-Talco fault system is not sealing. A CO2 storage project in the Woodbine aquifer would impact as many as 15 counties with high-pressure CO2 pipelines stretching as long as 875 km from the CO2 source to the injection site. The required percentage of power plant energy capacity was 7.43% for bulk injection, 7.9% for the external brine disposal case, and 10.2% for the internal saturated brine injection case. The estimated total cost was $0.001320́3$0.00146/kWh for the bulk injection, $0.001910́3$0.00211/kWh for the external brine disposal case, and $0.00190́3$0.00209/kWh for the internal saturated brine injection case.

Download or read book A Study of CO2 Storage Capacity Estimation in Sedimentary Rocks written by Polwattegallage Navinda Kishan De Silva and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The steady increase of human activities over the years has led to high atmospheric concentrations of greenhouse gases such as CO2 resulting in a steady rise of temperature levels, particularly over the last two decades. Therefore, the appropriate long-term storage of CO2 offers an attractive solution to reduce CO2 concentration in the atmosphere, especially in terms of storage of CO2 in abandoned coal seams with the potential of CH4 recovery (ECBM). However, previous studies on CO2 storage estimation methodologies in various sedimentary rocks are not adequate. Therefore, this study is focused on understanding and improving CO2 storage capacity estimation in sedimentary rocks.This thesis is a comprehensive summary of many aspects of my research, outlines the technical aspects of the research. CO2 storage estimation in sedimentary rocks has been studied comprehensively in numerical, empirical and experimental studies using a novel experimental set-up for coal and saline aquifers. This research aimed to understand and evaluate CO2 storage capacity in underground sedimentary rocks. Consequently, it is hoped that this research make a major contribution to climate warming studies as it focuses on CO2 storage estimation methodologies in coal and saline aquifers empirically, numerically and experimentally. Advanced experimental equipment has been developed with advanced features to observe pressure development along the sample. This equipment has the ability to regulate pressure and temperature. This apparatus was used to conduct permeability tests and storage estimations for Victorian brown coal specimens to investigate the effects of sub-critical and super-critical CO2 injections. The reconstituted coal samples were developed in the apparatus by compacting crushed coal using axial pressure loads. CO2 was then injected into the coal core while monitoring the injected CO2 under controlled pressure and temperature. Due to CO2 injection, coal swells as CO2 is adsorbed to the coal matrix. However, at increased pressures coal swelling increases,leading to increased storage capacity. Importantly, N2 has the potential to reverse CO2-induced swelling, recovering the lost permeability due to CO2 injection. Uniaxial compressive strength (UCS) testing was conducted on a reconstituted coal sample to observe compression load monitoring with an ARAMIS camera system. In this way, a compression load of 1.12 MPa was observed, which is consistent with the compressionload observed for previous UCS compaction of Victorian brown coal specimens. Numerical modelling was carried out using field-scale data as well as laboratory data using the COMET3 numerical simulator. The calibrated models showed good agreement with the field-scale model and the laboratory data. Then a sensitivity study was conducted to investigate the effects with respect to different coal parameters. Adsorption models were reviewed to investigate the accuracy of previous adsorption models, and adsorption models have been developed based on coal properties forbituminous coal types.

Download or read book Geological Storage of CO2 Long Term Security Aspects written by Axel Liebscher and published by Springer. This book was released on 2015-02-21 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the industrial use of secure, permanent storage technologies for carbon dioxide (CO2), especially geological CO2 storage. Readers are invited to discover how this greenhouse gas could be spared from permanent release into the atmosphere through storage in deep rock formations. Themes explored here include CO2 reservoir management, caprock formation, bio-chemical processes and fluid migration. Particular attention is given to groundwater protection, the improvement of sensor technology, borehole seals and cement quality. A collaborative work by scientists and industrial partners, this volume presents original research, it investigates several aspects of innovative technologies for medium-term use and it includes a detailed risk analysis. Coal-based power generation, energy consuming industrial processes (such as steel and cement) and the burning of biomass all result in carbon dioxide. Those involved in such industries who are considering geological storage of CO2, as well as earth scientists and engineers will value this book and the innovative monitoring methods described. Researchers in the field of computer imaging and pattern recognition will also find something of interest in these chapters.

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 Factors Determining Rapid and Efficient Geologic Storage of CO2 written by Lokendra Jain and published by . This book was released on 2011 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Implementing geological carbon sequestration at a scale large enough to mitigate emissions will involve the injection of supercritical CO2 into deep saline aquifers. The principal technical risks associated with such injection are that (i) buoyant CO2 will migrate out of the storage formation; (ii) pressure elevation during injection will limit storage rates and/or fracture the storage formation; and (iii) groundwater resources will be contaminated, directly or indirectly, by brine displaced from the storage formation. An alternative to injecting CO2 as a buoyant phase is to dissolve it into brine extracted from the storage formation, then inject the CO2-saturated brine into the storage formation. This "surface dissolution" strategy completely eliminates the risk of buoyant migration of stored CO2. It greatly mitigates the extent of pressure elevation during injection. It nearly eliminates the displacement of brine. To gain these benefits, however, it is essential to determine the costs of this method of risk reduction. This work provides a framework for optimization of the process, and hence for cost minimization. Several investigations have tabulated the storage capacity for CO2 in regions around the world, and it is widely accepted that sufficient pore volume exists in deep subsurface formations to permit large-scale sequestration of anthropogenic CO2. Given the urgency of implementing geologic sequestration and other emissions-mitigating technologies (storage rates of order 1 Gt C per year are needed within a few decades), the time required to fill a target formation with CO2 is just as important as the pore volume of that formation. To account for both these practical constraints we describe in this work a time-weighted storage capacity. This modified capacity integrates over time the maximum injection rate into a formation. The injection rate is a nonlinear function of time, formation properties and boundary conditions. The boundary conditions include the maximum allowable injection pressure and the nature of the storage formation (closed, infinite-acting, constant far-field pressure, etc.) The time-weighted storage capacity approaches the volumetric capacity as time increases. For short time intervals, however, the time-weighted storage capacity may be much less than the volumetric capacity. This work describes a method to compute time-weighted storage capacity for a database of more than 1200 North American oil reservoirs. Because all of these reservoirs have been commercially developed, their formation properties can be regarded as representative of aquifers that would be attractive targets for CO2 storage. We take the product of permeability and thickness as a measure of injectivity for a reservoir, and the product of average areal extent, net thickness and porosity as a measure of pore volume available for storage. We find that injectivity is not distributed uniformly with volume: the set of reservoirs with better than average injectivity comprises only 10% of the total volumetric storage capacity. Consequently, time weighted capacity on time scale of a few decades is 10% to 20% of the nominal volumetric capacity. The non-uniform distribution of injectivity and pore volume in the database coupled with multiphase flow effects yields a wide distribution of "filling times", i.e. the time required to place CO2 up to the boundaries of the formation. We define two limiting strategies based on fill times of the storage structures in the database and use them to calculate resource usage for a target storage rate. Since fill times are directly proportional to injectivity, smallest fill time corresponds to best injectivity and largest fill time corresponds to smallest injectivity. If best injectivity structures are used first, then the rate at which new structures would be needed is greater than if worst injectivity structures are used first. A target overall storage rate could be maintained for longer period of time when worst injectivity structures are used first. Because of the kh vs PV correlation, most of the pore volume remains unused when no extraction wells are used. Extraction wells require disposal of produced brine, which is a significant challenge, or beneficial use of the brine. An example of the latter is the surface dissolution process described in this thesis, which would enable use of a much greater fraction of the untouched pore volume.

Download or read book Geologic CO2 Storage written by YagnaDeepika Oruganti and published by . This book was released on 2010 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: When CO2 is injected in deep saline aquifers on the scale of gigatonnes, pressure buildup in the aquifer during injection will be a critical issue. Because fracturing, fault activation and leakage of brine along pathways such as abandoned wells all require a threshold pressure (Nicot et al., 2009); operators and regulators will be concerned with the spatial extent of the pressure buildup. Thus a critical contour of overpressure is a convenient proxy for risk. The location of this contour varies depending on the target aquifer properties (porosity, permeability etc.), the geology (presence of faults, abandoned wells etc.), and boundary conditions. Importantly, the extent also depends on relative permeability (Burton et al., 2008). First we describe ways of quantifying the risk due to pressure buildup in an aquifer with a constant pressure boundary, using the three-region injection model to derive analytical expressions for a specific contour of overpressure at any given time. All else being the same, the two-phase-region mobilities (and hence relative permeability characteristics) provide a basis for the ranking of storage formations based on risk associated with pressure elevation during injection. The pressure buildup during CO2 injection will depend strongly upon the boundary conditions at the boundary of the storage formation. An analytical model for pressure profile in the infinite-acting aquifer is developed by combining existing water influx models in traditional reservoir engineering (Van-Everdingen and Hurst model, Carter-Tracy model) to the current problem for describing brine efflux from the storage aquifer when CO2 injection creates a "three-region" saturation distribution. We determine evolution of overpressure with time for constant pressure, no-flow and infinite-acting boundary conditions, and conclude that constant pressure and no-flow boundary conditions give the most optimistic and pessimistic estimates of risk respectively. Compositional reservoir simulation results, using CMG-GEM simulator are presented, to show the effect of an isolated no-flow boundary on pressure buildup and injectivity in saline aquifers. We investigate the effect of multiple injection wells on single-phase fluid flow on aquifer pressure buildup, and demonstrate the use of an equivalent injection well concept to approximate the aquifer pressure profile. We show a relatively inexpensive method of predicting the presence of unanticipated heterogeneities in the formation, by employing routine measurements such as injection rate and injection pressure to track deviation in the plume path. This idea is implemented by combining Pro-HMS (probabilistic history matching software, that carries out geologically consistent parameter estimation), and a CMG-GEM model which has been tuned to the physics of the CO2-brine system.

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 Offsetting Water Requirements and Stress with Enhanced Water Recovery from CO2 Storage written by and published by . This book was released on 2016 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon dioxide (CO2) capture, utilization, and storage (CCUS) operations ultimately require injecting and storing CO2 into deep saline aquifers. Reservoir pressure typically rises as CO2 is injected increasing the cost and risk of CCUS and decreasing viable storage within the formation. Active management of the reservoir pressure through the extraction of brine can reduce the pressurization while providing a number of benefits including increased storage capacity for CO2, reduced risks linked to reservoir overpressure, and CO2 plume management. Through enhanced water recovery (EWR), brine within the saline aquifer can be extracted and treated through desalination technologies which could be used to offset the water requirements for thermoelectric power plants or local water needs such as agriculture, or produce a marketable such as lithium through mineral extraction. This paper discusses modeled scenarios of CO2 injection into the Rock Springs Uplift (RSU) formation in Wyoming with EWR. The Finite Element Heat and Mass Transfer Code (FEHM), developed by Los Alamos National Laboratory (LANL), was used to model CO2 injection with brine extraction and the corresponding pressure tradeoffs. Scenarios were compared in order to analyze how pressure management through the quantity and location of brine extraction wells can increase CO2 storage capacity and brine extraction while reducing risks associated with over pressurization. Future research will couple a cost-benefit analysis to these simulations in order to determine if the benefit of subsurface pressure management and increase CO2 storage capacity can outweigh multiple extraction wells with increased cost of installation and maintenance as well as treatment and/or disposal of the extracted brine.