Based on digital cores of oil shale obtained from high-temperature steam in-situ pyrolysis and micro-CT scanning experiments, the real structures of oil shale after pyrolysis at different temperatures were seamlessly integrated into COMSOL through precise grid partitioning. This enabled the simulation of in-situ steam-assisted oil recovery two-phase flow fields. The study examines the dynamic evolution of phase interfaces, pressure fields, velocity fields, and oil displacement efficiency during the in-situ two-phase flow process in pore structures with varying degrees of development. The research indicates that: Firstly, the development and connectivity of pore structures significantly influence the advancement speed of the phase interface — the better the pore structure development, the faster the phase interface advances. Secondly, as seepage progresses, the stability of phase interface advancement improves, with the difference between the peak δa value before stabilization and the stabilized δa value decreasing over time. Thirdly, at the moment of steam injection, a surge in Pa within the seepage zone occurs. The complexity of the pore structure effectively mitigates the surge in Pa caused by the instantaneous gas drive effect. Finally, the total seepage volumetric flow rate Qtotal increases with time. The oil production ratio α at the outlet decreases slightly with time, but remains above 97.6 %, demonstrating the effectiveness of steam-assisted oil recovery.

中文翻译：

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不同温度热解后单裂缝油页岩CT数字岩心原位蒸汽驱油渗流模拟


基于高温蒸汽原位热解获得的油页岩数字岩心和微型CT扫描实验，通过精确的网格划分，将不同温度下热解后的油页岩真实结构无缝集成到COMSOL中。这使得能够模拟原位蒸汽辅助采油两相流场。该研究考察了不同发育程度的孔隙结构中原位两相流动过程中相界面、压力场、速度场和驱油效率的动态演化。研究表明：首先，孔隙结构的发育程度和连通性显着影响相界面的推进速度——孔隙结构发育越好，相界面的推进速度越快。其次，随着渗流的进行，相界面推进的稳定性提高，稳定前的峰值δa值与稳定后的δa值之差随着时间的推移而减小。第三，在注蒸汽的瞬间，渗流区内出现Pa的激增。复杂的孔隙结构有效缓解了瞬时气驱效应引起的Pa升高。最后，总渗流体积流量Qtotal随时间增加。出口处的产油率α随着时间的推移略有下降，但仍保持在97.6%以上，证明了蒸汽辅助采油的有效性。