Experimental and numerical studies on Downhole gasification technique for improved oil recovery using a semi pilot rig

Gas injection is restricted by the need for surface facilities such as gas supply and storage. Downhole gasification of hydrocarbons (DHG) requires, instead, a portable electricity generator as the only surface facility. DHG consists in producing gases as H2, CO, CO2 and CH4 of a part of the produced oil in a reactor positioned alongside the producer well in the reservoir. The gases are injected into a gas cap above the oil formation. Once the maximum oil recovery is reached, the H2 generated can be commercialised for the future 'hydrogen economy' era. DHG had only been tested under laboratory conditions at reservoir pressure up to 130 bar and no numerical DHG model had been realised. From this starting point, experimental studies were carried out within the laboratory using the existing and unique DHG rig in the world on the small pilot scale. The investigation was directed mainly at extending the pressure range up to 160 bar in order to investigate whether the conversion and H2 production is maintained at acceptable levels for oil recovery. A basic numerical DHG model was also developed. The experimental and numerical results suggest that DHG is technically feasible at the pressures studied, 160 bar, perhaps up to 200 bar.