Oil-Recovery Mechanisms in Bitumen-Bearing Carbonate Rocks

Laboratory testing was conducted over a 6-year period to aid recovery of oil in the Grosmont formation’s bitumen-bearing carbonate reservoirs, with the intent of providing billions of barrels of oil for the Province of Alberta. Through experiments measuring oil recovery from varying water and steam processes, it was found that wet steam provides the most efficient displacement medium. The oil recovery shows a significant impact of thermal expansion and gas drive, which can lead to significant oil displacements at early times, specifically where the localized open-porosity network fractures is extensive. Bitumen recovery from carbonate systems is achieved through a combination of thermal expansion, gas drive, gravity drainage of oil out of connected open porosity, and imbibition of water into the rock matrix.