Case study on combined CO2 sequestration and low-salinity water production potential in a shallow saline aquifer in Qatar

Abstract

CO2 is one of the byproducts of natural gas production in Qatar. The high rate of natural gas production from Qatar's North Field (world's largest non-associated gas field) has led to the production of significant amounts of CO2. The release of CO2 into the atmosphere may be harmful from the perspective of global warming. In this work, we study the CO2 sequestration potential in Qatar's Aruma aquifer. The Aruma aquifer is a saline aquifer in the southwest of Qatar. It occupies an area of approximately 1985 km2 on land (16% of Qatar's total area). We have developed a compositional model for CO2 sequestration in the Aruma aquifer on the basis of available log and flow test data. We suggest water production at some distance from the CO2 injection wells as a possible way to control the pore pressure. This method increases the potential for safe sequestration of CO2 in the aquifer without losing integrity of the caprock and without any CO2 leakage. The water produced from this aquifer is considerably less saline than seawater and could be a good water source for the desalination process, which is currently the main source of water in Qatar. The outcome of the desalination process is water with higher salinity than the seawater that is currently discharged into the sea. This discharge can have negative long-term environmental effects. The water produced from the Aruma aquifer is considerably less saline than seawater and can be a partial solution to this problem.