Carbon Dioxide Geosequestration Research Articles

Underground carbon sequestration as a component of decarbonization in anthropogenic activity

The article discusses why it is appropriate to talk about carbon utilization even in cases where the goal is to reduce carbon dioxide emissions into the environment. An explanation is given as to why underground carbon dioxide burial (geosequestration) is the main feasible solution for the decarbonization of anthropogenic activity at the planetary scale. A brief review of existing or promising practices of carbon dioxide geosequestration is provided. The economic and technological aspects of the implementation of geosequestration projects, affecting their feasibility, are viewed, as well as the relevant statistics of such projects over the first two decades of the XXI century. In particular, the extremely low percentage of implementation of planned projects is noted in the majority of industrial sectors consuming fossil hydrocarbon fuels. The regional aspect of the problem is considered in relation to the work of industrial companies of the Perm Region and their foreign economic activity under the conditions of the enacted and planned legislation. The available potential of the regions’s subsoil for geosequestration of carbon dioxide is stated - oil collectors, coal seams of the sealed mines of the Kizelovsky basin, salt deposits of the Verkhnekamsky deposit.

Hybrid numerical methods for modelling multi-physics mass transport in coal

It is a challenging task to predict and analyse the transient flow physics in unconventional complex geological formations such as coal seams. This is due to the multi-scale multi-physics nature of processes taking place in coal seam gas reservoirs. Therefore, numerical tools allowing the incorporation of various flow physics inherent to coal into the simulation routine are of particular importance. At the pore-scale, the rock images obtained by micro-computed tomography are frequently used for flow modelling in porous or fractured media by direct numerical simulations (Lattice Boltzman method or by solving Navier Stokes equations) or by utilising so-called pore-network modelling. Both methods have advantages and drawbacks, while their hybridisation may allow us avoid some of the major pitfalls. Due to a limited number of research dedicated to image-based pore-scale modelling in coal, we develop a hybrid numerical model that combines the Hagen-Poiseuille analytical solution and the volume of fluid advection scheme for fluid flow in fractures with the continuum Darcy flow in the coal matrix. The explicit coupling of fluid flow across the fracture-matrix domains is implemented via corresponding source terms in the governing equations. Besides, additional physics including sorption and matrix swelling-shrinkage phenomena are introduced into the numerical model. The hybrid solver is validated against analytical solutions and a previously developed Darcy-Brinkman-Stokes framework, which has similar functionality for modelling fluid flow in coal seams. To validate the developed model and show its capability to capture multi-scale multi-physics flow in coal, several illustrative simulations are conducted using synthetic and realistic digital images of coal. As a result, the accuracy of the hybrid solver was within 4% when compared to the Darcy-Brinkman-Stokes framework for flow simulation on realistic geometry. Besides, the non-parallelised hybrid model outperformed the parallelised direct numerical simulation, being more than 90 times faster in terms of computational time. The findings are beneficial for conducting larger core-scale simulations of multi-scale multi-physics flow in coal seams with potential applications to natural gas production, hydrogen storage, and carbon dioxide geosequestration.

An image-based coal network model for simulating hydro-mechanical gas flow in coal: An application to carbon dioxide geo-sequestration

CO2 geo-sequestration is a practical approach to achieve net-zero carbon target. However, one of the main challenges for successful CO2 geo-sequestration is the reduced coal permeability and injectivity that are caused by coal swelling. Coal has complex and heterogenous internal pore and fracture structure. The processes of gases adsorbing, desorbing, and transporting within multiscale heterogeneous coal structures are more complicated compared with conventional rocks. This paper aims to gain insights about the gas transport behaviours in coal by developing a coupled model to simulate gas flow multiphysics as well as dynamic coal deformation. This work develops an image-based 3D fracture network model, called Fracture Box Model (FBNM). In this model, each fracture is described by arrays of box elements such that the regional change of fracture opening widths can be preserved. Compared with other fracture models (e.g. discrete fracture network), FBNM can simulate complicated multiphysical gas transport more efficiently, but also be able to simulate corresponding coal matrix deformation. By comparing permeability results between direct simulation method with FBNM, it is found that FBNM can effectively estimate the permeability of original fracture networks, but requiring significantly less computational cost. To study the implications of gas types, effective stress, gas adsorption, and thermal expansion on coal permeability, gas injection pressures, gas types, coal seam temperatures are varied and investigated in the simulations. In addition to the advantage of computational efficiency, FBNM is more preferable for complicated flow transport simulations where direct simulation methods are still challenging. This work provides a promising framework which could be further developed for multiphase and multicomponent flow simulations for CO2 geo-sequestration projects.

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二酸化炭素地下貯留技術の現状と展望

Simulating the chemical kinetics of CO2-methane exchange in hydrate

Carbon dioxide exchange with methane in the clathrate structure has been shown beneficial in laboratory experiments and has been suggested as a field-scale technique for production of natural gas from gas-hydrate bearing sediments. Furthermore, the method is environmentally attractive due to the formation of CO2-hydrate in the sediments, leading to the geosequestration of carbon dioxide. However, the knowledge is still limited on the impact of small-scale heterogeneities on hydrate dissociation kinetics. In the present study, we developed a model for simulating laboratory experiments of carbon dioxide injection into a pressure vessel containing a mixture of gas hydrate and quartz sand. Four experiments at different temperature and pressure conditions were modeled. The model assumes that the contents are ideally mixed and aims to estimate the effective dissociation rate of gas hydrate by matching the model results with the experimental observations. Simulation results indicate that with a marginal offset the model was able to simulate different hydrate dissociation experiments, in particular, those that are performed at high pressures and low temperatures. At low pressures and high temperatures large discrepancies were noticed between the model results and the experimental observations. The mismatches were attributed to the development of extremely heterogeneous flow patterns at pore-scale, where field-scale models usually assume the characteristics to be uniform. Through this modeling study we estimated the irreversible dissociation rate of methane- and CO2-hydrate as 0.02 and 0.03 mol m−3s−1, respectively.

Experimental Study of Supercritical CO2 Injected into Water Saturated Medium Rank Coal by X-ray MicroCT

Carbon dioxide geosequestration into deep unmineable coal seams is a technique which can mitigate anthropogenic greenhouse gas emissions. However, coal composition is always complex, and some minerals such as calcite chemically react when exposed to the acidic environment (which is created by scCO2 mixing with formation water). These reactive transport processes are still poorly understood. We thus imaged a water-bearing heterogeneous coal (calcite rich) core before and after scCO2 injection in-situ at high resolutions (3.43 µm) in 3D via X-ray in-situ microCT flooding system. Indeed, the calcite-coal mixed layer was partially dissolved, and absolute porosity and connectivity significantly increased. We thus suggested that such process could be used as an acidizing method in CO2 ECBM. However, such dissolved damage also can significantly affect the rock mechanical properties and potentially induce geohazards.

Experimental pore-scale analysis of carbon dioxide hydrate in sandstone via X-Ray micro-computed tomography

Carbon dioxide geo-sequestration (CGS) into sediments in the form of (gas) hydrates is one proposed method for reducing anthropogenic carbon dioxide emissions to the atmosphere and, thus reducing global warming and climate change. However, there is a serious lack of understanding of how such CO2 hydrate forms and exists in sediments. We thus imaged CO2 hydrate distribution in sandstone, and investigated the hydrate morphology and cluster characteristics via x-ray micro-computed tomography in 3D in-situ. A substantial amount of gas hydrate (∼17% saturation) was observed, and the stochastically distributed hydrate clusters followed power-law relations with respect to their size distributions and surface area-volume relationships. The layer-like hydrate configuration is expected to reduce CO2 mobility in the reservoir, and the smaller than expected hydrate surface-area/volume ratio will reduce methane production and CO2 storage capacities. These findings will aid large-scale implementation of industrial CGS projects via the hydrate route.

The role of natural fractures of finite double-porosity aquifers on diffusive leakage of brine during geological storage of CO2

The diffusive leakage rate (DLR) of brine from a finite fractured aquifer into intact overlying and underlying layers during geosequestration of carbon dioxide is modeled using a two-dimensional radial domain. To handle the interaction between aquifer and caprock or overlying layer (underlying layer), continuities of pressures and fluid fluxes are taken into account at the aquifer-caprock interface. In order to solve this problem, Laplace transform and finite Hankel transform are adopted. The early-time and late-time solutions for DLR of brine from a double-porosity aquifer are also examined using the developed general solution. The solutions are used to analyze DLR from the fractured aquifer into overlying formation and the average pressures in the fractured aquifer and the caprock during injection and post injection periods. Variations of DLR and the average pressures in the fractured aquifer and the caprock with the double-porosity parameters are characterized. It is shown that DLR of brine and the average pressures in the aquifer and the caprock are sensitive to double-porosity parameters during CO2 injection when ratio of the horizontal fracture to the caprock permeabilities (kfh1D) is small. However, they remain practically insensitive to double-porosity parameters for a large kfh1D. The results also confirm that DLR of brine reaches to a fixed pseudo-steady state value at late times during CO2 injection. In addition, the post injection DLR for low to moderate values of kfh1D is found to be negligible while for high value of kfh1D DLR is more evident. These results find applications in geological storage of CO2 in fractured saline aquifers.

The coupled reaction and crystal growth mechanism of tricalcium silicate (C3S): An experimental study for carbon dioxide geo-sequestration wells

Based on the decades of studies and commercial experiments, the geo-sequestration of carbon dioxide (CO2) has been the most efficient way to solve the green gas emission problem for the world. As the vital barrier of the sequestration well, the cement shell must be credible and durable until the well is abandoned. To date, some of sequestration projects have operated for many years, however, CO2 leakage has been a major threat in these projects. Although, ordinary Portland cement (OPC) is widely used in these projects, it has been found to be unstable in acidic environments. To assess these potential risks, this study combines cement hydration and carbonation as a coupled reaction to study the cement at an early age. OPC contents are too complex to study, thus, the main phase of C3S in the OPC was assessed in the CO2 environment. The experimental results indicate that the coupled reaction was considerably different from that in a previous study. In regard to the hydration reaction, cement slurry may provide the leakage pathway for sequestered CO2. In addition, the carbonation product is composed of an unstable crystal, which has proved to dissolve during long-lasting experiments.

Diffusive leakage of brine from aquifers during CO2 geological storage

Abstract The area of investigation in this study is designed around an improved understanding of fundamentals of the diffusive leakage of brine from a storage aquifer into overlying and underlying low permeability layers during geosequestration of carbon dioxide (CO2) through development of a theoretical model. Here, we consider a two-dimensional domain in cylindrical coordinates, comprised of an aquifer and an overburden, where the interaction between the two media is handled by imposing the continuities of pressures and fluid fluxes at the aquifer-overburden interface. This coupled problem is solved by successive implementation of the Laplace and finite Hankel transforms. The developed solutions can be used to analyze diffusive leakage of brine from the aquifer into overburden and generate type curves for average pressures in the aquifer and overburden during injection and post injection periods. The results show that the leakage rate at early times is scaled with t 1/2 while it remains constant at late times. It is also shown that the average pressure in the aquifer is scaled with t for short and long times. Moreover, the average pressure in the overburden is scaled with t at late times while it is scaled with t 3/2 at early times. In addition, the results reveal that factors affecting diffusive leakage rate through intact overburden during CO2 storage are, in decreasing order of significance, thickness of overburden, thickness of aquifer, aquifer to overburden permeability ratio, and aquifer to overburden porosity ratio. However, thickness of aquifer has minimal effect on diffusive leakage of brine within post injection period. To evaluate the theoretical model, case studies for two potential sites in United Kingdom, one in Lincolnshire and the other one in the Firth of Forth, are conducted. The field studies show that the diffusive leakage from the aquifer into the overburden diminishes ∼40 years after the injection has ceased for Lincolnshire while it stops after ∼12 years for Firth of Forth. The average amount of the brine leaked from the aquifers per standard cubic meter (Sm3) of the injected CO2 through diffusive leakage was found to be 6.28 × 10−4 m3 of brine (or 0.330 kg of brine/kg of CO2) over ∼70 years for Lincolnshire and 4.59 × 10−4 m3 of brine (or 0.242 kg of brine/kg of CO2) over ∼42 years for Firth of Forth.

Carbon geosequestration in limestone: Pore-scale dissolution and geomechanical weakening

Carbon dioxide geosequestration in deep saline aquifers or oil and gas reservoirs is a key technology to mitigate anthropogenic greenhouse gas emissions. Porous carbonate rock is a potential host rock for CO2 storage; however, carbonate rock chemically reacts when exposed to the acidic brine (which is created by the addition of CO2, CO2-saturated brine). These reactive transport processes are only poorly understood, particularly at the micrometre scale, and importantly how this affects the geomechanical rock properties. We thus imaged a heterogeneous oolitic limestone (Savonnières limestone) core before and after flooding with brine and CO2-saturated brine at representative reservoir conditions (323K temperature, 10MPa pore pressure, 5MPa effective stress) in-situ at high resolutions (3.43μm and 1.25μm voxel size) in 3D with an x-ray micro-computed tomograph; and measured the changes in nano-scale mechanical properties induced by acid exposure. Indeed the carbonate rock matrix partially dissolved, and absolute and effective porosity and permeability significantly increased. This dissolution was confined to the original flow channels and inlet points. Importantly, the rock matrix weakened significantly (- 47% in indentation modulus) due to the acid exposure.

Editorial: Flow and Transformation in Porous Media

Fluid flow in transforming porous rocks, fracture networks, and granular media is subject to considerable current interdisciplinary research activity in Physics, Earth Sciences, and Engineering. Examples of natural and engineered processes include hydrocarbon recovery, carbon dioxide geo-sequestration, soil drying and wetting, pollution remediation, soil liquefaction, landslides, dynamics of wet or dry granular media, dynamics of faulting or friction, volcanic eruptions, gas venting in sediments, karst development and speleogenesis, ore deposit development, and radioactive waste disposal. Hydrodynamic flow instabilities and pore scale disorder typically result in complex flow patterning. In transforming media, additional mechanisms come into play: compaction, de-compaction, erosion, segregation, and fracturing lead to changes in permeability over time. Dissolution, precipitation, and chemical reactions between solutes and solids may gradually alter the composition and structure of the solid matrix, either creating or destroying permeable paths for fluid flow. A complex, dynamic feedback thus arises where, on the one hand, the fluid flow affects the characteristics of the porous medium, and on the other hand the changing medium influences the fluid flow. This Research Topic Ebook presents current research illustrating the depth and breadth of ongoing work in the field of flow and transformation in porous media through 15 papers by 72 authors from around the world. The body of work highlights the challenges posed by the vast range of length-and timescales over which subsurface flow processes occur. Importantly, phenomena from each scale contribute to the larger-scale behavior. The flow of oil and gas in reservoirs, and the flow of groundwater on catchment scale is sensitively linked to pore scale processes and material heterogeneity down to the micrometer scale. The geological features of the same reservoirs and catchments evolved over millions of years, sometimes as a consequence of cracking and fracture growth occurring on the time scale of microseconds. The research presented by the authors of this Research Topic represents a step toward bridging the separation of scales as well as the separation of scientific disciplines so that a more unified picture of flow and transformation in porous media can start to emerge.

Parametric analysis of caprock integrity in relation with CO2 geosequestration: capillary breakthrough pressure of caprock and gas effective permeability

AbstractCaprock integrity is a primary criterion for evaluating depleted oil and gas reservoirs for long‐term safety of carbon dioxide geosequestration. The occurrence of capillary leakage is inevitable in caprock. This phenomenon occurs whenever the buoyancy pressure due to accumulated CO2 plumes dominates the capillary pressure of caprock, and thereby the plumes intrude into the pore throats. In this study, experimental investigation of the effective parameters, including overburden pressure, ambient temperature, and CO2 impurities in the form of non‐condensable and non‐reactive CH4 and N2 gases on the capability of shale and anhydrite cores to preserve CO2 gas is conducted. In this regard, capillary breakthrough pressure and CO2 gas effective permeability analysis were performed applying two distinct techniques, step by step and residual capillary pressure. Experiments were conducted at the temperatures of 35, 70, and 90 °C and overburden pressures in the range of 3500–5800 psi. Two main seal rocks, including shale and anhydrite core samples, from middle Asmari and Gachsaran formations of the Zagros Basin located in the southwest of Iran were used. Regarding the high capillary breakthrough pressure and low gas effective permeability after outbreak of the leakage, all three parameters have noticeable effects on capillary sealing efficiency of the caprocks. The results indicate that impurities such as CH4 and N2 have a significant effect on capillary breakthrough pressure of caprock and gas effective permeability. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd

Rock formation characterization for carbon dioxide geosequestration: 3D seismic amplitude and coherency anomalies, and seismic petrophysical facies classification, Wellington and Anson-Bates Fields, Kansas, USA

Abstract Higher resolution rock formation characterization is of paramount priority, amid growing interest in injecting carbon dioxide, CO2, into subsurface rock formations of depeleting/depleted hydrocarbon reservoirs or saline aquifers in order to reduce emissions of greenhouse gases. In this paper, we present a case study for a Mississippian carbonate characterization integrating post-stack seismic attributes, well log porosities, and seismic petrophysical facies classification. We evaluated changes in petrophysical lithofacies and reveal structural facies-controls in the study area. Three cross-plot clusters in a plot of well log porosity and acoustic impedance corroborated a Neural Network petrophysical facies classification, which was based on training and validation utilizing three petrophysically-different wells and three volume seismic attributes, extracted from a time window including the wavelet of the reservoir-top reflection. Reworked lithofacies along small-throw faults has been revealed based on comparing coherency and seismic petrophysical facies. The main objective of this study is to put an emphasis on reservoir characterization that is both optimized for and subsequently benefiting from pilot tertiary CO2 carbon geosequestration in a depleting reservoir and also in the deeper saline aquifer of the Arbuckle Group, south central Kansas. The 3D seismic coherency attribute, we calculated from a window embracing the Mississippian top reflection event, indicated anomalous features that can be interpreted as a change in lithofacies or faulting effect. An Artificial Neural Network (ANN) lithofacies modeling has been used to better understand these subtle features, and also provide petrophysical classes, which will benefit flow-simulation modeling and/or time-lapse seismic monitoring feasibility analysis. This paper emphasizes the need of paying greater attention to small-scale features when embarking upon characterization of a reservoir or saline-aquifer for CO2 based carbon geosequestration.

The Latrobe Group and the 90-million-year beach

Carbon dioxide geosequestration requires a detailed understanding of the whole sedimentary section, with particular emphasis on topseals and intraformational seals. Hydrocarbon exploration is more focused on reservoirs but requires a similar basin understanding. This extended abstract reviews the knowledge gained from petroleum exploration in the Gippsland Basin to The CarbonNet Project’s exploration program for CO2 storage. The Ninety Mile Beach on the Gippsland coast is a prominent modern-day sand fairway where longshore drift transports sediments north-eastwards along a barrier-bar system, trapping lake systems behind the coastal strip. This beach is only 10,000 years old (dating to the last glacial rise of sea level) but is built on a platform of earlier beaches that can be traced back almost 90 million years to the initiation of Latrobe Group deposition in the Gippsland Basin. Using a recently compiled and open-file volume of merged 3D seismic surveys, the authors show the evolution of the Latrobe shoreline can be mapped continuously from the Upper Cretaceous to the present day. Sand fairways accumulate as a barrier-bar system at the edge of a steadily subsiding marine embayment, with distinct retrogradational geometries. Behind the barrier system, a series of trapped lakes and lagoons are mapped. In these, coal swamps, extensive shales, and tidal sediments were deposited at different stages of the sea-level curve, while fluvial systems prograded through these lowlands. Detailed 3D seismic extractions show the geometry, orientation and extent of coals, sealing shales, fluvial channels, and bayhead deltas. Detailed understanding of these reservoir and seal systems outlines multi-storey play fairways for hydrocarbon exploration and geosequestration. Use of modern basin resource needs careful coordination of activity and benefits greatly from established data-sharing practices.

The permeability of geopolymer at down-hole stress conditions: Application for carbon dioxide sequestration wells

Emissions of greenhouse gases have been a major problem for the world for many decades, and the geo-sequestration of carbon dioxide (CO2) has been proposed as one of the best solutions for the reduction of anthropogenic greenhouse gas emissions. The injection well and the well cement play vital roles in the sustainability of a sequestration project, and CO2 leakage through the wellbore and well cement has been found to be the major threat to the success of sequestration projects. Therefore, the permeability of well cement should be low to avoid leakage in the wellbore. To date, ordinary Portland cement (OPC) based well cement has been used, and it has been found to be unstable in the CO2 environment as it provides pathways for CO2 leakage. One of the best replacements for OPC would be geopolymer cement as it possesses excellent strength, acid resistance and durability compared to OPC. Therefore, this paper addresses geopolymer as well cement in place of OPC and discusses its permeability. In the first phase of this work, previous studies relevant to the permeability of existing oil well cement and geopolymer cement were analysed. In the second phase, an experimental study was conducted to study the CO2 permeability of geopolymer under tri-axial conditions, using the high pressure tri-axial set-up available in the Monash University laboratory. Based on the experimental results, the apparent CO2 permeability of geopolymer is in the range of 2×10−21–6×10−20m2 and it is less than the CO2 permeability of typical oil well cement (10−20–10−11m2). This indicates that geopolymer is a good replacement for existing OPC-based cement as it has lower CO2 permeability. At a given confining pressure, the permeability of geopolymer reduces with the increase in injection pressure and this is attributed to Klinkenberg’s effect. When the confining pressure is increased from 10 to 25MPa, the permeability reduction is 60% at lower injection pressures (5MPa). The corresponding reduction is 35% at higher injection pressures (>10MPa) as the permeability value reaches its intrinsic permeability at higher injection pressures. In addition, CO2 permeability reduces with confining stress for all the injection pressures studied.

Microtomographic Quantification of Hydraulic Clay Mineral Displacement Effects During a CO2 Sequestration Experiment with Saline Aquifer Sandstone

We combined a noninvasive tomographic imaging technique with an invasive open-system core-flooding experiment and compared the results of the pre- and postflooded states of an experimental sandstone core sample from an ongoing field trial for carbon dioxide geosequestration. For the experiment, a rock core sample of 80 mL volume was taken from the 629 m Stuttgart Formation storage domain of a saline sandstone aquifer at the CCS research pilot plant Ketzin, Germany. Supercritical carbon dioxide and synthetical brine were injected under in situ reservoir p/T-conditions at an average flow rate of 0.1 mL/min for 256 h. X-ray computed microtomographic imaging was carried out before and after the core-flooding experiment at a spatial voxel resolution of 27 μm. No significant changes in microstructure were found at the tomographic imaging resolution including porosity and pore size distribution, except of an increase of depositional heterogeneous distribution of clay minerals in the pores. The digitized rock data were used as direct real microstructure input to the GeoDict software package, to simulate Navier-Stokes flow by a lattice Boltzmann equation solver. This procedure yielded 3D pressure and flow velocity fields, and revealed that the migration of clay particles decreased the permeability tensor probably due to clogging of pore openings.

A Novel Testing Apparatus for Hydromechanical Investigation of Rocks: Geo-Sequestration of Carbon dioxide

This paper presents the design, development and application of a new multi-phase high-pressure and elevated temperature rock hydromechanical testing apparatus for the investigation of reservoir and cap rock behaviour in carbon geo-sequestration projects. The triaxial apparatus is designed to support high confining stress, injection pressures and higher temperatures to imitate the natural thermo-hydro-geomechanical conditions of deep underground geological formations. The apparatus also includes an acoustic emission device for the study of the mechanical failure behaviour of rocks under compression. The apparatus is designed to support a range of different rock specimen sizes from 34 to 54 mm in diameter. Since sequestration projects involve the injection of supercritical carbon dioxide, which is extremely sensitive to temperature and pressure, and is highly corrosive in nature, special precautions were taken in the design and manufacture of the apparatus. The data acquisition system is powered and calibrated in accordance with each of the sensors and is guided by a series of in-house developed and commercial softwares for data storage and analysis. The methodology for conducting advanced testing on cap rock and reservoir rocks with the injection of water and supercritical CO2 is presented with the appropriate theory. Some preliminary tests have been carried out on sandstone specimens sourced from the Melbourne region using the newly designed apparatus and the results are presented in this paper.

Study of Caprock Integrity in Geosequestration of Carbon Dioxide

The Industrial Revolution has led to a substantial increase in the emission of greenhouse gas (GHG) such as carbon dioxide (CO2) into the atmosphere, exacerbating the global-warming phenomenon. One option to mitigate GHG emission is by capturing and safely storing the CO2 in suitable deep underground geological formations. This paper provides a literature review on the potential changes in permeability and geomechanical properties of the caprock and sedimentary reservoir rock caused by the injected CO2 under in situ conditions, highlighting the factors that can potentially hamper the caprock’s integrity. A two-dimensional (2D) axisymmetric numerical model of an ideal CO2 reservoir with 30 years of injection and 70 years of monitoring phase is also presented. The model results suggest that, for the parametric values and reservoir conditions used in the model, the injection pressure leads to an increase in pore pressure, thereby reducing the effective stress in the formation. An induced vertical displacemen...

Subsurface design considerations for carbon dioxide storage

Abstract Over the past three decades the oil and gas industry has developed full-system approaches for safe and cost-effective injection of carbon dioxide (CO2). Projects have been executed successfully that inject into formations spanning a full range of depths, reservoir quality, pressures and temperatures. Injection has been into both aquifers and hydrocarbon bearing intervals. Lessons learned about site selection, storage design and site monitoring are directly applicable to current and future carbon dioxide geosequestration projects. In this paper the focus will be on storage project field experience and simulation-based investigations of plume growth and migration in different geologic settings. Also discussed will be options to optimize well rates and location to maximize the storage volumes of CO2 injection. Safe, efficient and reliable long term storage of CO2 will require knowledge and observance of limits on cap rock fracture pressures, location of formation spill points and maximum rates of injection to mitigate adverse sweep related to gravity override of injected gas. Study outcomes and key design parameters for three different storage scenarios will be discussed. One will be a depleted oil field in an anticline structure connected to a regional aquifer; a second will be storage into a deep and lower quality aquifer underlying a gas field and a third will be assessment of potential storage in a large regional aquifer in pressure communication with active producing fields. By use of specific examples across a range of possible storage scenarios we will illustrate that site specific data combined with detailed dynamic modelling is very important to a complete appraisal of storage site integrity and capacity. The terms corporation, company, affiliate, ExxonMobil, Exxon, Mobil, Esso, our, we and its, as used in this material may refer to Exxon Mobil Corporation, to one of its divisions, or to the companies affiliated with Exxon Mobil Corporation, or to any one or more of the foregoing. The shorter terms are used merely for convenience and simplicity.