Non-isothermal injection-induced geomechanics in a porous layer confined with flexible sealing rocks

Abstract

Non-isothermal injection of fluids deep into geological strata results in coupled alterations in in-situ temperatures and pore pressures, inducing deformations within the target rock and surrounding media. This paper presents new closed-form thermo-poroelastic solutions for spatiotemporal pore pressure, temperature, and displacements induced in a porous continuum confined with flexible sealing rocks, during early stages of injection when the rock temperature adjacent to the wellbore is within a transient state. Reservoir response in the direction perpendicular to flow is incorporated using the Winkler model. A comprehensive analysis reveals the duration of the transient state for various rocks to be rather substantial. While temperature profiles obtained from the proposed solutions are fairly similar to those of conventional solutions, thermal-induced pore pressures are demonstrated to be very different, resulting in a distinct geomechanical response of the confined layer specifically near the wellbore region. Vertical confinement is found to be notably influential on thermal-induced geomechanical response of a confined porous layer.