In-situ solvents generation enhanced steam assisted gravity drainage (ISSG-SAGD): A low carbon and high-efficiency approach for heavy oil recovery

The primary bottleneck in heavy oil production lies in the significant energy consumption and CO2 emissions associated with steam injection for recovery. To address this challenge, we propose the ISSG-SAGD (in-situ solvent generation enhanced steam assisted gravity drainage) technique. The recovery mechanisms and operational strategies are investigated using a numerical simulation with an Athabasca bitumen reservoir model, affirming the considerable environmental and economic potential of ISSG-SAGD. The results demonstrate that ISSG-SAGD integrates the recovery mechanisms of both SAGP (steam and gas push) and ES-SAGD (expanding solvent SAGD). Moreover, employing cyclic steam injection, maintaining low operating pressure, and initiating ISSG-SAGD at an early stage enable a 33.79 % reduction in steam consumption, a 39 % decrease in average carbon intensity, a 5.40 % increase in oil production, and a 61.28 % rise in net present value compared to conventional SAGD. This study proves that the ISSG-SAGD approach offers a sustainable and efficient alternative for future heavy oil recovery endeavors, addresses the challenges of high energy consumption and carbon emissions, and paves the way towards a green and economically viable future for the heavy oil development.