A screening framework study to evaluate CO₂storage performance in single and stacked caprock–reservoir systems of the Northern Appalachian Basin

Abstract

In the context of geologic carbon dioxide (CO2) sequestration, the storage effectiveness of a caprock–reservoir system is a function of the properties of both the caprock and reservoir – namely, the ability of the caprock to prevent upward leakage of CO2 (caprock sealing capability), the mechanical response of the reservoir and caprock (by evaluating in situ stress changes), and the extent and degree to which CO2 can be trapped over long periods of time. In this work, all three parameters were considered to evaluate the storage effectiveness of the Cambrian–Ordovician sequence of the Northern Appalachian Basin. We constructed a series of hydro‐mechanical models to investigate interactions between CO2 flow and geomechanical processes and to evaluate the three aspects of storage performance. Models were built to evaluate two scenarios: (1) single reservoirs with a single overlying caprock, and (2) systems comprising multiple reservoirs and multiple intermediate caprock units in addition to the primary (uppermost) caprock unit. The overall conclusion of the work is that focusing only on one aspect of storage effectiveness might not necessarily warrant long‐term CO2 storage. Results of the sensitivity analysis for the single caprock–reservoir system show that each storage effectiveness metric has its own control parameters. A comparison among three stacked caprock–reservoir systems in different parts of the study area shows that each location in the study area could be appropriate for one of the storage effectiveness metrics. Therefore, we conclude that the screening process to select the best site for CO2 sequestration should be based on an evaluation of all three metrics. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

The effect of Biot coefficient and elastic moduli stress–pore pressure dependency on poroelastic response to fluid injection: laboratory experiments and geomechanical modeling

“…Geomechanical processes associated with subsurface injection of fluids (e.g., CO 2 injection, brine disposal) could have significant impacts on the safety and long‐term storage of the injected fluid 1,2 . Reservoir inflation, surface uplift, fracturing of the reservoir and/or caprock, fault activation, wellbore failure, and casing damage are examples of geomechanical‐related risks, which can have significant environmental consequences such as groundwater contamination due to CO 2 leakage, 3,4 and seismicity with possible ground motion due to fault activation 5–9 .…”

“…Reservoir inflation, surface uplift, fracturing of the reservoir and/or caprock, fault activation, wellbore failure, and casing damage are examples of geomechanical‐related risks, which can have significant environmental consequences such as groundwater contamination due to CO 2 leakage, 3,4 and seismicity with possible ground motion due to fault activation 5–9 . Field tests, 2,10,11 laboratory experiments, 12–15 and geomechanical modeling 16–18 provide tools to evaluate the likelihood and severity of geomechanical responses. Before fluid injection, field tests can be used to characterize the hydromechanical characteristics of formations, fracture network parameters, as well as the state of stress in the caprock–reservoir formations 2,10 .…”

“…Field tests, 2,10,11 laboratory experiments, 12–15 and geomechanical modeling 16–18 provide tools to evaluate the likelihood and severity of geomechanical responses. Before fluid injection, field tests can be used to characterize the hydromechanical characteristics of formations, fracture network parameters, as well as the state of stress in the caprock–reservoir formations 2,10 . During fluid injection, monitoring methods such as interferometric synthetic aperture radar (InSAR) measurement and microseismic monitoring can be used to measure critical response parameters such as surface uplift, mechanical integrity, and faults and fractures activation 3,19 .…”

Statistical based hydromechanical models to estimate poroelastic effects of CO2 injection into a closed reservoir

“…Poroelastic effects of injection determine the final stress state in the reservoir as a precursor to evaluating tensile and shear failure potential . The final in situ stress also limits the practical injectivity of the reservoirs . Ground surface uplift and induced seismicity, which could have a detrimental effect on the safety of the injection site and its surrounding area, also depends on the poroelastic effect of injection as well as the stiffness of the reservoir and surrounding rocks …”

“…7,8 The final in situ stress also limits the practical injectivity of the reservoirs. 2,9,10 Ground surface uplift and induced seismicity, which could have a detrimental effect on the safety of the injection site and its surrounding area, also depends on the poroelastic effect of injection as well as the stiffness of the reservoir and surrounding rocks. [11][12][13][14][15] Coupled hydromechanical modeling is typically used for evaluation of the poroelastic effect of injection as well as the resulting geomechanical outcomes such as the potential for fracturing in reservoirs, analysis of slippage along faults, surface uplift, and associated seismicity.…”