Study of vertical displacement of caprock associated with CO2 injection into an oil reservoir using numerical simulation

CO2 sequestration is a mitigation method for reducing greenhouse gas emissions to the atmosphere. Geomechanical changes of the caprock overlying the storage reservoir have an important effect on success and safety of any CO2 sequestration operation. Subsurface CO2 injection leads to a pore pressure increase and a decrease of effective stresses, which may results in vertical displacement of the caprock, the caprock failure and subsequent CO2 leakage. In this study, a 3D geomechanical finite element model was built by using Abaqus software to investigate the effects of CO2 injection on the caprock vertical displacement. The results show that maximum uplift of the reservoir-caprock interface occurs near the injection well, the most critical part of the caprock, which is equal to 19 mm after 10 years of injection. Also, majority of vertical displacements occurs at the early times of injection. Results of the numerical model were validated against an analytical solution.

Keywords:

Vertical displacement , Caprock , CO2 sequestration , Oil reservoir , Numerical model