A Modeling Approach in FLAC to Predict Hydro-Mechanical Response of subsurface Storage Reservoirs due to CO2 Injection

Prassetyo, S.H. (Colorado School of Mines) | Gutierrez, M. (Colorado School of Mines)



This paper demonstrates the ability of a 2D independent two-phase flow hydro-mechanical (H-M) simulator, FLAC (Fast Lagrangian Analysis of Continua), to predict H-M responses related to Co2 injection in subsurface disposal reservoirs. This is the first paper to study the use of FLAC as a single H-M simulator for Co2 injection processes. The models in FLAC are tested against twoexistingmodels: (1)a prototype Co2injectionreservoirand(2)the InSalahgas fieldinAlgeria.The H-M responses such as the spread of Co2 plumes, the history of pore pressure increases, and surface uplifts are presented and compared with the results from the reference models. The potential for mechanical failures and leakage are also analyzed using critical pressure approach. The simulations show that FLAC models are able to capture typical shapes of Co2 plumes in the reservoirs. The history of pore pressure increase and a typical bell-shape for surface uplifts are obtained. The potential location for mechanical failures and leakage is also well predicted. Future implementation of H-M stress-dependent properties in FLAC will improve its capability. Hence, coupling this software with other fluid flow simulator such in the literatures may no longer be necessary in the future.