| Increase in CO2 emission has become an important issue over the years due to its environmental impacts as a greenhouse gas. The fact that these emissions are primarily derived from energy consumption and that 85% of the primary power is supplied by fossil fuels (Orr, 2004), makes the reduction of CO2 emissions a major challenge. CO2 sequestration in the geological formations has been identified as an alternative to counter the impact of the emissions. CO2 sequestration refers to the capture and long term storage of CO2.;In order to properly asses the viability of CO2 sequestration in a geological formation as a "safe" and long term solution, several questions have to be answered: Is this formation capable of trapping the amount of CO2 to be injected? Does the seal of this formation (the cap rock) have the proper characteristics to ensure a low risk structural trapping? Which trapping mechanisms are present and what kind of interactions (geochemical, geomechanical, etc.) are we to expect as we inject the CO2? These questions are addressed and evaluated in this research.;The proposed research addresses these questions in the context of an ongoing CO2 storage project in a deep saline aquifer located in the Citronelle field in Mobile, Alabama. A full field reservoir model was built using information from the actual field site and reservoir scale simulations are performed. Initially we evaluated different trapping mechanisms (residual or capillary trapping, solubility, mineral and structural trapping) and their contribution to the storage process. Quality and integrity of the cap rock, representing the ability to trap "mobile" CO2 structurally, is studied to assess the potential risk of leakage. Additionally, impact of the nature of the edge boundary conditions on the pressure and saturation distribution throughout the reservoir is studied.;Finally, in order to ensure the long term storage of the CO2, a Post-Injection Site Care (PISC) study is performed. Pressure stabilization time is assessed within acceptable thresholds, allowing for possible post-stabilization leakage of brine or CO2 detection. |
