Download or read book Compositional Reservoir Simulation based Reactive transport Formulations with Application to CO2 Storage in Sandstone and Ultramafic Formations written by Sara Forough Farshidi and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical reactions are important in many simulation applications, including geological carbon storage. The incorporation of chemical reaction treatment in general compositional reservoir simulators is thus necessary to enable this modeling. In this work, we develop robust numerical schemes for modeling CO2 sequestration. All of the methods developed are implemented into Stanford's Automatic Differentiation-based General Purpose Research Simulator (AD-GPRS). We first address a special case of crossing thermodynamic phase boundaries, i.e., aqueous phase disappearance and reappearance in the context of CO2 sequestration. A specialized treatment for handling aqueous-phase components when the aqueous phase disappears (or reappears) is introduced under the natural set of variables. This variable set includes pressure, phase saturations, and phase compositions. We demonstrate the robustness of our fully-implicit natural-variable formulation for carbon storage simulations, even when the aqueous phase disappears in multiple grid blocks. We also propose a novel reactive transport formulation based on overall-composition variables. This formulation effectively treats the aqueous phase disappearance phenomenon, because the overall-composition variables are valid for all fluid-phase combinations. Overall-composition variables, however, suffer from the high cost of thermodynamic calculations in two-phase grid blocks. This motivates the development of a hybrid numerical scheme which takes advantage of the favorable features of both the natural and overall-composition variable formulations. Simulation results for CO2 sequestration scenarios with the three formulations demonstrate the stability of these schemes. A comparison of the numerical performance of these treatments suggests that the use of natural variables in general offers enhanced computational efficiency compared to overall-composition variables. Under the natural-variable formulation, however, one of the special treatments proposed in this work should be considered for grid blocks with single-phase gas. We next investigate the use of ultramafic rocks for geological carbon storage. These rocks are highly reactive and offer considerable CO2 storage capacity. We begin by analyzing a weathering system in this type of rock, where our AD-GPRS implementation is validated against field observations. We then simulate idealized carbon storage projects in an ultramafic reservoir. The general features and patterns of carbonation are identified and discussed. This type of rock offers nearly complete conversion of the injected CO2 to mineral forms in many cases, enhancing storage security. Sensitivity analyses are conducted to examine the impact of various reservoir properties and operation parameters on carbonation efficiency. We demonstrate that well control scenarios can be designed to improve the carbonation process substantially by providing a more effective distribution of the injected CO2 in the formation.

Download or read book Three phase Compositional Reservoir Simulation Model Coupled with Reactive Transport for CO2 Storage in the Farnsworth Unit Ochiltree County Texas written by Eusebius Junior Kutsienyo and published by . This book was released on 2019 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reactive Transport Modeling written by Yitian Xiao and published by John Wiley & Sons. This book was released on 2018-03-12 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt: Teaches the application of Reactive Transport Modeling (RTM) for subsurface systems in order to expedite the understanding of the behavior of complex geological systems This book lays out the basic principles and approaches of Reactive Transport Modeling (RTM) for surface and subsurface environments, presenting specific workflows and applications. The techniques discussed are being increasingly commonly used in a wide range of research fields, and the information provided covers fundamental theory, practical issues in running reactive transport models, and how to apply techniques in specific areas. The need for RTM in engineered facilities, such as nuclear waste repositories or CO2 storage sites, is ever increasing, because the prediction of the future evolution of these systems has become a legal obligation. With increasing recognition of the power of these approaches, and their widening adoption, comes responsibility to ensure appropriate application of available tools. This book aims to provide the requisite understanding of key aspects of RTM, and in doing so help identify and thus avoid potential pitfalls. Reactive Transport Modeling covers: the application of RTM for CO2 sequestration and geothermal energy development; reservoir quality prediction; modeling diagenesis; modeling geochemical processes in oil & gas production; modeling gas hydrate production; reactive transport in fractured and porous media; reactive transport studies for nuclear waste disposal; reactive flow modeling in hydrothermal systems; and modeling biogeochemical processes. Key features include: A comprehensive reference for scientists and practitioners entering the area of reactive transport modeling (RTM) Presented by internationally known experts in the field Covers fundamental theory, practical issues in running reactive transport models, and hands-on examples for applying techniques in specific areas Teaches readers to appreciate the power of RTM and to stimulate usage and application Reactive Transport Modeling is written for graduate students and researchers in academia, government laboratories, and industry who are interested in applying reactive transport modeling to the topic of their research. The book will also appeal to geochemists, hydrogeologists, geophysicists, earth scientists, environmental engineers, and environmental chemists.

Download or read book Reactive Transport in Natural and Engineered Systems written by Jennifer Druhan and published by Walter de Gruyter GmbH & Co KG. This book was released on 2020-03-04 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: Open system behavior is predicated on a fundamental relationship between the timescale over which mass is transported and the timescale over which it is chemically transformed. This relationship describes the basis for the multidisciplinary field of reactive transport (RT). In the 20 years since publication of Review in Mineralogy and Geochemistry volume 34: Reactive Transport in Porous Media, RT principles have expanded beyond early applications largely based in contaminant hydrology to become broadly utilized throughout the Earth Sciences. RT is now employed to address a wide variety of natural and engineered systems across diverse spatial and temporal scales, in tandem with advances in computational capability, quantitative imaging and reactive interface characterization techniques. The present volume reviews the diversity of reactive transport applications developed over the past 20 years, ranging from the understanding of basic processes at the nano- to micrometer scale to the prediction of Earth global cycling processes at the watershed scale. Key areas of RT development are highlighted to continue advancing our capabilities to predict mass and energy transfer in natural and engineered systems.

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 Integrated Reservoir Studies for CO2 Enhanced Oil Recovery and Sequestration written by Shib Sankar Ganguli and published by Springer. This book was released on 2017-03-30 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the feasibility of CO2-EOR and sequestration in a mature Indian oil field, pursuing for the first time a cross-disciplinary approach that combines the results from reservoir modeling and flow simulation, rock physics modeling, geomechanics, and time-lapse (4D) seismic monitoring study. The key findings presented indicate that the field under study holds great potential for enhanced oil recovery (EOR) and subsequent CO2 storage. Experts around the globe argue that storing CO2 by means of enhanced oil recovery (EOR) could support climate change mitigation by reducing the amount of CO2 emissions in the atmosphere by ca. 20%. CO2-EOR and sequestration is a cutting-edge and emerging field of research in India, and there is an urgent need to assess Indian hydrocarbon reservoirs for the feasibility of CO2-EOR and storage. Combining the fundamentals of the technique with concrete examples, the book is essential reading for all researchers, students and oil & gas professionals who want to fully understand CO2-EOR and its geologic sequestration process in mature oil fields.

Download or read book Reactive Transport Modelling of CO2 Storage in Saline Aquifers to Elucidate Fundamental Processes Trapping Mechanisms and Sequestration Partitioning written by and published by . This book was released on 2004 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ultimate fate of CO2 injected into saline aquifers for environmental isolation is governed by three interdependent yet conceptually distinct processes: CO2 migration as a buoyant immiscible fluid phase, direct chemical interaction of this rising plume with ambient saline waters, and its indirect chemical interaction with aquifer and cap-rock minerals through the aqueous wetting phase. Each process is directly linked to a corresponding trapping mechanism: immiscible plume migration to hydrodynamic trapping, plume-water interaction to solubility trapping, and plume-mineral interaction to mineral trapping. In this study, reactive transport modeling of CO2 storage in a shale-capped sandstone aquifer at Sleipner has elucidated and established key parametric dependencies of these fundamental processes, the associated trapping mechanisms, and sequestration partitioning among them during consecutive 10-year prograde (active-injection) and retrograde (post-injection) regimes. Intra-aquifer permeability structure controls the path of immiscible CO2 migration, thereby establishing the spatial framework of plume-aquifer interaction and the potential effectiveness of solubility and mineral trapping. Inter-bedded thin shales--which occur at Sleipner--retard vertical and promote lateral plume migration, thereby significantly expanding this framework and enhancing this potential. Actual efficacy of these trapping mechanisms is determined by compositional characteristics of the aquifer and cap rock: the degree of solubility trapping decreases with increasing formation-water salinity, while that of mineral trapping is proportional to the bulk concentration of carbonate-forming elements--principally Fe, Mg, Ca, Na, and Al. In the near-field environment of Sleipner-like settings, 80-85% by mass of injected CO2 remains and migrates as an immiscible fluid phase, 15-20% dissolves into formation waters, and less than 1% precipitates as carbonate minerals. This partitioning defines the relative effectiveness of hydrodynamic, solubility, and mineral trapping on a mass basis. Seemingly inconsequential, mineral trapping has enormous strategic significance: it maintains injectivity, delineates the storage volume, and improves cap-rock integrity. We have identified four distinct mechanisms: dawsonite [NaAlCO3(OH)2] cementation occurs throughout the intra-aquifer plume, while calcite-group carbonates [principally, (Fe, Mg, Ca)CO3] precipitate via disparate processes along lateral and upper plume margins, and by yet another process within inter-bedded and cap-rock shales. The coupled mineral dissolution/precipitation reaction associated with each mechanism reduces local porosity and permeability. For Sleipner-like settings, the magnitude of such reduction for dawsonite cementation is near negligible; hence, this process effectively maintains initial CO2 injectivity. Of similarly small magnitude is the reduction associated with formation of carbonate rind along upper and lateral plume boundaries; these processes effectively delineate the CO2 storage volume, and for saline aquifers anomalously rich in Fe-Mg-Ca may partially self-seal the plume. Porosity and permeability reduction is most extreme within shales, because their clay-rich mineralogy defines bulk Fe-Mg concentrations much greater than those of saline aquifers. In the basal cap-rock shale of our models, these reductions amount to 4.5 and 13%, respectively, after the prograde regime. During the retrograde phase, residual saturation of immiscible CO2 maintains the prograde extent of solubility trapping while continuously enhancing that of mineral trapping. At the close of our 20-year simulations, initial porosity and permeability of the basal cap-rock shale have been reduced by 8 and 22%, respectively. Extrapolating to hypothetical complete consumption of Fe-Mg-bearing shale minerals (here, 10 vol.% Mg-chlorite) yields an ultimate reduction of about 52 and 90%, respectively, after 130 years. Hence, the most crucial strategic impact of mineral trapping in Sleipner-like settings: it continuously improves hydrodynamic seal integrity of the cap rock and, therefore, containment of the immiscible plume and solubility trapped CO2.

Download or read book Geochemical Modelling of CO2 Storage written by Ozgur Gundogan and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The injection of CO2 into the reservoir acidifies the brine, which in turn drives mineral dissolution and precipitation processes. This thesis explores how far geochemical modelling can be applied to evaluate the CO2-brine-rock interactions during CO2 storage in North Sea saline formations. First, modelling requirements and the capabilities and limitations of the numerical codes used in this study (PHREEQC, GEM, TOUGHREACT and MoReS) were identified. Solubility of CO2 in brine by different models at conditions relevant to CO2 storage was compared. Batch modelling of three sandstone core samples from target CO2 storage formations was performed to compare the numerical codes and assess mineral trapping capacity of the formations. Finally, reactive transport modelling of Rannoch formation at reservoir scale was studied. The simulation results of GEM and MoReS were compared. It was shown that current codes can model geochemical reactions with acceptable simplifications and the choice of simulator is not critical for the model predictions. It was demonstrated how thermodynamic data and activity models can affect the modelling results. It was also found that the models are sensitive to relative mineral composition, grid discretization, permeability models, and kinetic parameters. Mineral trapping is comparable to solubility trapping in Rannoch formation.

Download or read book Reactive Transport in Porous Media written by Peter C. Lichtner and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-12-17 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 34 of Reviews in Mineralogy focuses on methods to describe the extent and consequences of reactive flow and transport in natural subsurface systems. Since the field of reactive transport within the Earth Sciences is a highly multidisciplinary area of research, including geochemistry, geology, physics, chemistry, hydrology, and engineering, this book is an attempt to some extent bridge the gap between these different disciplines. This volume contains the contributions presented at a short course held in Golden, Colorado, October 25-27, 1996 in conjunction with the Mineralogical Society of America's (MSA) Annual Meeting with the Geological Society of America in Denver, Colorado.

Download or read book Multiphase Flow and Reactive Transport Modelling of CO2 Storage in Heterogeneous Reservoirs written by Jolene Lorraine Hermanson and published by . This book was released on 2013 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study addresses how physical heterogeneity, representing different sedimentary rock layers and the relationships between those layers, impacts the distribution of CO2, and thus the type and extent of mineral dissolution and precipitation reactions during CO2 geologic storage in deep saline aquifers. Numerical multiphase flow (TOUGH2) and reactive transport codes (TOUGHREACT) were used to construct a series of reservoir scale simulations to investigate how the flow controlling parameter values, distribution, and grid refinement of various hydrostratigraphic units (HSUs) affect the distribution of CO2, pH and mineral reactions. Physical heterogeneity is critical for controlling the distribution of supercritical and dissolved CO2, the redistribution of ions from geochemically reactive materials to more stable portions of the reservoir, mixing and dilution of CO2-rich waters, and the extent of mineral dissolution and precipitation reactions. The highest magnitude of carbonate mineral precipitation occurs at the sandstone-siltstone interface and along the extent of the CO2-water contact.

Download or read book Reactive Transport Modeling of Cap Rock Integrity During Natural and Engineered CO2 Storage written by and published by . This book was released on 2004 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Long-term cap rock integrity represents the single most important constraint on the long-term isolation performance of natural and engineered CO2 storage sites. CO2 influx that forms natural accumulations and CO2 injection for EOR/sequestration or saline-aquifer disposal both lead to concomitant geochemical alteration and geomechanical deformation of the cap rock, enhancing or degrading its seal integrity depending on the relative effectiveness of these interdependent processes. Using our reactive transport simulator (NUFT), supporting geochemical databases and software (GEMBOCHS, SUPCRT92), and distinct-element geomechanical model (LDEC), we have shown that influx-triggered mineral dissolution/precipitation reactions within typical shale cap rocks continuously reduce microfracture apertures, while pressure and effective-stress evolution first rapidly increase then slowly constrict them. For a given shale composition, the extent of geochemical enhancement is nearly independent of key reservoir properties (permeability and lateral continuity) that distinguish EOR/sequestration and saline-aquifer settings and CO2 influx parameters (rate, focality, and duration) that distinguish engineered disposal sites and natural accumulations, because these characteristics and parameters have negligible (indirect) impact on mineral dissolution/precipitation rates. In contrast, the extent of geomechanical degradation is highly dependent on these reservoir properties and influx parameters because they effectively dictate magnitude of the pressure perturbation; specifically, initial geomechanical degradation has been shown inversely proportional to reservoir permeability and lateral continuity and proportional to influx rate. Hence, while the extent of geochemical alteration is nearly independent of filling mode, that of geomechanical deformation is significantly more pronounced during engineered injection. This distinction limits the extent to which naturally-occurring CO2 reservoirs and engineered storage sites can be considered analogous. In addition, the pressure increase associated with CO2 accumulation in any compartmentalized system invariably results in net geomechanical aperture widening of cap-rock microfractures. This suggests that ultimate restoration of pre-influx hydrodynamic seal integrity--in both EOR/sequestration and natural accumulation settings--hinges on ultimate geochemical counterbalancing of this geomechanical effect. To explore this hypothesis, we have introduced a new conceptual framework that depicts such counterbalancing as a function of effective diffusion distance and reaction progress. This framework reveals that ultimate counterbalancing of geochemical and geomechanical effects is feasible, which suggests that shale cap rocks may in fact evolve into effective seals in both natural and engineered storage sites.

Download or read book Reactive Transport Modeling to Study Changes in Water Chemistry Induced by CO2 Injection at the Frio I Brine Pilot written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To demonstrate the potential for geologic storage of CO2 in saline aquifers, the Frio-I Brine Pilot was conducted, during which 1600 tons of CO2 were injected into a high-permeability sandstone and the resulting subsurface plume of CO2 was monitored using a variety of hydrogeological, geophysical, and geochemical techniques. Fluid samples were obtained before CO2 injection for baseline geochemical characterization, during the CO2 injection to track its breakthrough at a nearby observation well, and after injection to investigate changes in fluid composition and potential leakage into an overlying zone. Following CO2 breakthrough at the observation well, brine samples showed sharp drops in pH, pronounced increases in HCO3− and aqueous Fe, and significant shifts in the isotopic compositions of H2O and dissolved inorganic carbon. Based on a calibrated 1-D radial flow model, reactive transport modeling was performed for the Frio-I Brine Pilot. A simple kinetic model of Fe release from the solid to aqueous phase was developed, which can reproduce the observed increases in aqueous Fe concentration. Brine samples collected after half a year had lower Fe concentrations due to carbonate precipitation, and this trend can be also captured by our modeling. The paper provides a method for estimating potential mobile Fe inventory, and its bounding concentration in the storage formation from limited observation data. Long-term simulations show that the CO2 plume gradually spreads outward due to capillary forces, and the gas saturation gradually decreases due to its dissolution and precipitation of carbonates. The gas phase is predicted to disappear after 500 years. Elevated aqueous CO2 concentrations remain for a longer time, but eventually decrease due to carbonate precipitation. For the Frio-I Brine Pilot, all injected CO2 could ultimately be sequestered as carbonate minerals.

Download or read book Actualistic and Geochemical Modeling of Reservoir Rock CO2 and Formation Fluid Interaction Citronelle Oil Field Alabama written by and published by . This book was released on 2014 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report includes description of the Citronelle field study area and the work carried out in the project to characterize the geology and composition of reservoir rock material and to collect an analyze the geochemical composition of produced fluid waters from the Citronelle field. Reservoir rock samples collected from well bore core were made into thin-sections and assessed for textural properties, including pore types and porosity distribution. Compositional framework grain modal data were collected via point-counting, and grain and cement mineralogy was assessed using SEM-EDS. Geochemistry of fluid samples is described and modeled using PHREEQC. Composition of rock and produced fluids were used as inputs for TOUGHREACT reactive transport modeling, which determined the rock-fluid system was in disequilibrium.

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 Reactive Transport Modeling of CO2 Through Cementitious Materials Under CO2 Geological Storage Conditions written by Jiyun Shen and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A reactive transport model is proposed to simulate the reactivity of cement based material in contact with CO2-saturated brine and supercritical CO2 (scCO2) under CO2 geological storage conditions. This code is developed to solve simultaneously transport and chemistry by a global coupled approach, considering the effect of temperature and pressure. The variability of scCO2 properties with pressure and temperature, such as solubility in water, density and viscosity are taken into account. It is assumed that all chemical processes are in thermodynamical equilibrium. Dissolution and precipitation reactions for portlandite (CH) and calcite (CC) are described by mass action laws and threshold of ion activity products in order to account for complete dissolved minerals. A chemical kinetics for the dissolution and precipitation of CH and CC is introduced to facilitate numerical convergence. One properly chosen variable is able to capture the precipitation and dissolution of the relevant phase. A generalization of the mass action law is developed and applied to calcium silicate hydrates (C-S-H) to take into account the continuous variation (decrease) of the Ca/Si ratio during the dissolution reaction of C-S-H. The changes in porosity and microstructure induced by the precipitation and dissolution reactions are also taken into account. Couplings between transport equations and chemical reactions are treated thanks to five mass balance equations written for each atom (Ca, Si, C, K, Cl) as well as one equation for charge balance and one for the total mass. Ion transport is described by using the Nernst-Plank equation as well as advection, while gas and liquid mass flows are governed by advection. Effect of the microstructure and saturation change during carbonation to transport properties is also considered. The model is implemented within a finite-volume code, Bil. Principles of this method and modeling approach are discussed and illustrated with the help of a simple example. This model, with all the efforts above, is able to simulate the carbonation processes for cement based materials, at both saturated and unsaturated conditions, in a wide CO2 concentration, temperature and pressure range. Several sets of experiments, including sandstone-like conditions, limestone-like conditions, supercritical CO2 boundary and unsaturated conditions reported in the literature are simulated. Good predictions are provided by the code when compared with experimental observations. Some experimental observed phenomena are also explained by the model in terms of calcite precipitation front, CH dissolution front, porosity profile, etc.

Download or read book Predictive Modeling of CO sub 2 Sequestration in Deep Saline Sandstone Reservoirs written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: One idea for mitigating the increase in fossil-fuel generated CO2 in the atmosphere is to inject CO2 into subsurface saline sandstone reservoirs. To decide whether to try such sequestration at a globally significant scale will require the ability to predict the fate of injected CO2. Thus, models are needed to predict the rates and extents of subsurface rock-water-gas interactions. Several reactive transport models for CO2 sequestration created in the last decade predicted sequestration in sandstone reservoirs of ~17 to ~90 kg CO2 m{sup -3.

Download or read book Numerical Modeling of CO2 water rock Interactions in the Farnsworth Texas Hydrocarbon Unit USA written by Bulbul Ahmmed and published by . This book was released on 2015 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical speciation, reaction path, and reactive transport modeling were used to study the effects on pore water composition and mineralogy from CO2 injection into the Pennsylvanian Morrow B Sandstone in the Farnsworth Unit in northern Texas to evaluate its potential for long-term CO2 sequestration. Speciation modeling showed the present Morrow B formation water to be supersaturated with respect to an assemblage of zeolite, clay, carbonate, mica, and aluminum hydroxide minerals, and quartz. The principal accessory minerals in the Morrow B, feldspars and chlorite, were predicted to dissolve. A reaction path model in which CO2 was progressively titrated up to its solubility limit into the Morrow B formation water showed the pH to decrease from its initial value of 7 to about 4.1 to 4.2, accompanied by the precipitation of small amounts of quartz, diaspore, and witherite. As the resultant CO2-charged fluid reacted with more of the Morrow B mineral matrix, the pH rose, reaching a maximum of 5.1 to 5.2 at a water:rock ratio of 10:1. At a higher water:rock ratio of 100:1, the pH rose to only 4.6 to 4.7. Diaspore, quartz, and nontronite precipitated consistently regardless of the water:rock ratio, but the carbonate minerals, siderite, witherite, dolomite, and calcite, only precipitated at higher pH. As a result, CO2 sequestration by mineral trapping was predicted to be important only at low water:rock ratios, accounting for a maximum of 2% of the titrated CO2 at the lowest water:rock ratio investigated of 10:1, which corresponds to a small porosity increase of about 1.4 to 1.5%. Reactive solute transport modeling extended the reaction path modeling by including the effects of multi-phase fluid flow, heat transport, and solute transport with the chemical reactions. CO2 was injected at nine wells in the western part of the field for 10 years in the model simulations. During injection, fluid pressures near the wells rose from about 15 MPa to about 19.2 MPa, but quickly dissipated after injection ceased. A plume of immiscible CO2 gas built up around the wells, reaching pore saturations of about 50%, but did not migrate far from the wells over time. In contrast, CO2 dissolved into aqueous solution was transported to the eastern boundary of the field within 30 years. The pH in the aqueous CO2 plume was as low as 4.74 and led to the dissolution of most of the native minerals in the Morrow B Sandstone matrix. Over the 30 years time of the simulations thus far, ankerite was the only carbonate mineral predicted to precipitate, and thus the only mineral sink for CO2. Most of the injected CO2 over the time frame of the simulations was predicted to be sequestered by hydrodynamic trapping, followed by solubility and mineral trapping, respectively. The amounts of mineral precipitation and dissolution were too small to affect the porosity and permeability significantly, meaning that the hydraulics of the aquifer should not be significantly affected by CO2 injection.