A fluid pressure and deformation analysis for geological sequestration of carbon dioxide

We present a fluid pressure and deformation analysis for geological sequestration of carbon dioxide based on a simplified hydro-mechanical model. This model includes the geomechanical part that relies on the theory of linear elasticity, while the fluid flow is based on the Darcy's law. Two parts are coupled together using the linear poroelasticity theory. For a typical geological sequestration in a semi-infinite geometry with diminishing pressure and deformation fields at infinity, the Helmholtz decomposition can be applied to the displacement vector. Hence, the flow equation can be decoupled from the equation of linear elasticity. Solutions for fluid pressure were obtained for this typical scenario and solutions for ground deformation were obtained using the method of Green's function. Finally, solutions were compared against numerical results using a finite element method for aquifers with two different thicknesses. General agreement can be obtained between analytical and numerical solutions. The model is useful in estimating the temporal and spatial variation of fluid pressure and the mechanical deformation during the entire injection period.

► The paper is based on a coupled hydro-mechanical model from linear poroelasticity.
► The model can be decoupled using Helmholtz decomposition.
► The paper presents simplified solutions for fluid pressure and deformation.
► Solutions can be used to estimate the variation of fluid pressure, deformation, and stress.