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

Abstract

In this study, a statistical‐based methodology is used to evaluate the poroelastic effects of injection during CO2 geologic sequestration in a closed reservoir. We constructed a series of hydromechanical models to evaluate the poroelastic effect of injection by quantifying total stress changes inside the reservoir, reservoir displacement, and surface uplift. The models are representative of closed carbonate reef reservoirs of the Michigan basin. A combination of experimental design for seven independent parameters (depth, caprock and reservoir Young's modulus, caprock and reservoir Poisson's ratio, pressure, and Biot's coefficient) and response surface modeling was used to develop statistical‐based reduced‐order models. We performed 147 numerical simulations to develop simplified models. The poroelastic model responses were captured using a standard quadratic model with full interaction terms, as well as a reduced model with only statistically significant coefficients. The interpretation of reduced‐order models, using R2 loss method, shows that while surface uplift depends mainly on the depth of the reservoir, stress increase depends mainly on Biot's coefficient. The developed statistical‐based models provide a quick tool to evaluate the poroelastic effect of injection into the closed carbonate reservoirs of the Michigan basin. Reduced‐order models were then combined with a Monte Carlo simulation to perform poroelastic uncertainty analyses and achieve a better understanding of the poroelastic performance of CO2 storage in the closed carbonate system of the Michigan basin. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.

Coupled Large Scale Hydromechanical Modelling for Caprock Failure Risk Assessment of Gas Storage in Aquifer

“…The pore pressure is the pressure borne or transmitted by the fluid in the rock, and the effective stress is the stress transmitted by the contact surface between the rock-solid particles. Many laboratory experiments have shown that the pore pressure P has different effects on deformation and failure of the fluid fully or partially saturated porous solid [29,30]. Both theoretical and experimental studies have shown that failure is controlled by the effective stress.…”

Quantifying the impact of effective stress on changes in elastic wave velocities due to CO2 injection into a depleted carbonate reef

“…Fluid saturation and pore pressure changes in the reservoir due to CO 2 injection alter elastic wave velocities 4 . In situ stresses can also be changed in the reservoir due to the poroelastic response to CO 2 injection 5–7 . The amount of stress changes in the reservoir depends on the geomechanical properties of reservoir and surrounding formations, amount of injected CO 2 , and associated pore pressure changes 6,8 .…”

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

“…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 .…”

“…Geomechanical modeling is essential to assess different aspects of the geomechanical‐related risks quantitatively and ensure safety and security of CO 2 storage. The objective of the geomechanical modeling is to estimate injection‐induced stress and strain of the reservoir, caprock, and the other overlying formations up to the Earth's surface 16–18,20,21 . These geomechanical responses can then be interpreted to assess geomechanical risks.…”

“…Different geomechanical models (e.g., analytical poroelastic solutions, numerical coupled models, and statistical‐based models) 18,20,22,23 have been introduced to address geomechanical‐related risks. Each approach can be selected by considering the objective of geomechanical modeling, complexity of the system (heterogeneity and anisotropy of the geological formations), and required modeling computational time.…”