浅薄层稠油水平井混合气与助排剂辅助蒸汽吞吐研究

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

为进一步研究水平井混合气(烟道气)与助排剂辅助蒸汽吞吐技术在浅薄层稠油油藏的应用,利用室内物理模拟实验对辅助方式的驱油效率和封堵能力进行评价,并通过数值模拟方法对研究区块适合水平井混合气助排剂辅助蒸汽吞吐的地质界限及最优参数进行限定和优化。研究结果表明,混合气助排剂辅助蒸汽驱的驱油效率比纯蒸汽驱、蒸汽助排剂驱和蒸汽氮气助排剂驱分别高出16.2%、11.0%和8.0%。混合气助排剂综合作用形成的泡沫封堵能力优于其他辅剂。研究区块适用于该技术的临界有效厚度随渗透率的增加而减小,临界渗透率随有效厚度的增大而增加。在确定研究区块地质界限的基础上,通过不同的渗透率和有效厚度组合,得到适合于该区块的注入参数,即混注比、注汽强度和混合气助排剂注入量的优化图版和取值范围。在实际区块进行了2口水平井的成功试验,为该技术在浅薄层稠油油藏的扩展应用提供了借鉴。

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 evalu- ated 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 perme- ability. 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.