ConocoPhillips
Solvents and NCG-co-injection with tapered pressure

Abstract:

A variation of expanding solvent steam assisted gravity drainage (ES-SAGD) production of heavy oil wherein steam and hydrocarbon solvent are co-injected into a heavy oil reservoir and water, hydrocarbon solvent and heavy oil are produced by gravity drainage until the steam chamber is well developed or until oil recovery reaches about 20-30% of oil in place. At that time, the wells are switched to a lateral sweep using non-condensible gas (NSG) and steam co-injection, where more hydrocarbon solvent is recovered than is recovered with ES-SAGD used alone and where the cumulative steam to oil ratio is reduced over using -ES-SAGD alone.