Effect of CO2 Injection in Stimulation of Geopressured Geothermal Reservoir

Abstract

Geopressured brines are a vast geothermal resource in the US Gulf of Mexico region. In particular, geopressured sandstones near salt domes are potential sources of geothermal energy because salt diapirs with high thermal conductivity may pierce younger, cooler strata. These characteristics enhance transfer heat from older, hotter strata at the base of the diapir into shallower strata. Moreover, widespread geopressure in the Gulf region tends to preserve permeability, enhancing productivity. As an example, the Camerina A sand of South Louisiana was chosen as a geomodel for a numerical simulation study of effects of CO2 injection and wellbore cooling as the innovative method of geothermal development. This paper presents scenarios for heat harvesting from typical Gulf of Mexico geopressured aquifers including Camerina A that take advantage of coupled convection and simultaneous CO2 sequestration. A suite of TOUGH2 numerical simulations demonstrates benefits of introducing CO2 injection wells, varying locations of injection/production segments of wells, and exploiting gravity segregation of the fluids.