Flexibility study of horizontal well cyclic steam simulation assisted by combination gas and cleanup addictive for shallow-thin heavy oil reservoir

In order to further study the application of combination gas （fuel gas） and cleanup additive assisted cyclic steam simulation technology in shallow-thin layer heavy oil reservoir, oil displacement efficiency and plugging capability of four assisting patterns were evaluated by laboratory physical simulation experiment, and then the geological boundary and optimum parameters of horizontal well cyclic steam simulation assisted by combination gas and cleanup agent adapted to the target block were defined and optimized through numerical simulation. The results show that the displacement efficiency of steam flooding assisted by combination gas and cleanup additive stays 16.2%, 11.0% and 8.0% higher than that of pure steam flooding, cleanup additive assisted steam flooding and nitrogen cleanup addictive assisted steam flooding, respectively. The sealing capability of foam formed by the combination of gas and cleanup agent is superior to others. For this block, the critical effective thickness of horizontal well cyclic steam simulation assisted by combination gas and cleanup agent decreases with the increase of permeability. And the critical permeability increases as effective thickness enlarges. Based on the determination of geological boundary, the optimum charts and range for mixed injection ratio, steam injection strength and injection volume of combination gas and cleanup additive are acquired by varying different permeability and effective thickness combination. This technology has been successfully applied in two horizontal wells, which provides a guiding role in expanding this technology in shallow-thin layer heavy oil reservoir.