Laboratory investigation of thermally-assisted gas–oil gravity drainage for secondary and tertiary oil recovery in fractured models

Heavy oil in Middle East fractured carbonate reservoirs account for 25–30% of the total oil in place in the region. Production of heavy oil from such reservoirs is thought to play an important role in the future of the ever-growing world's energy consumption.Besides, having very active water drives, some of these reservoirs are already depleted resulted in high residual oil in place. To enhance the oil recovery efficiency, the mechanism of thermally-assisted gas–oil gravity drainage for secondary and tertiary oil recovery was investigated on a fractured laboratory model. Very high recovery efficiencies were achieved due to oil viscosity reduction as well as gravity stability of the gas–oil contact in both oil-wet and water-wet fractured porous media. It was also noted that a combination of waterflooding and thermal recovery is very effective to enhance heavy oil recovery from fractured water-wet and oil-wet models.