Thermo-Mechanical Coupled Modeling to Assess CO2 Storage Integrity in A Depleted Gas Reservoir

A CCS injection feasibility study was conducted in a heavily depleted carbonate reservoir located in the Sharjah, UAE. This included conducting geomechanical analysis to confirm that the depleted reservoir is safe for CO2 injection under various injection strategies.

The high recovery rate, isolated fault blocks, and competent caprock have led to significant pressure depletion, reducing total stresses and inducing reservoir deformation. Furthermore, injected CO2 is expected to expand upon reservoir entry, causing thermal cooling in proximity to the injectors due to the Joule-Thomson effect ( Oldenburg 2006 ). All this represents a potential risk for cap rock, reservoir and fault integrity during the injection and monitoring phases; therefore, understanding the interplay between reservoir properties, geomechanical history, and thermo-mechanical fluid-rock dynamics is crucial for assessing CO2 storage feasibility.

This paper outlines a thermo-mechanical one-way coupling setup that integrates the thermal dynamic model with the 3D geomechanical model to assess reservoir and field behaviour during the injection and monitoring periods, as well as potential risks and injection constraints.