中深层稠油油藏化学辅助蒸汽驱三维物理模拟与应用

胜利油田稠油油藏由于埋深和边底水的影响，油藏压力无法降低到5 MPa以下再进行蒸汽驱，一般转驱压力为7 MPa。为进一步提高蒸汽驱的实施效果，利用室内实验研究了化学辅助驱方式进一步提高采收率。以胜利油田孤岛油田Ng5层位直井反九点井网为原型开展物理模拟研究。通过对比单纯蒸汽驱、化学辅助蒸汽驱等不同方式提高采收率的幅度，对泡沫剂、驱油剂不同注入方式进行对比分析，并确定现场实施方式。室内实验研究结果表明：采用“先调后驱”的化学辅助蒸汽驱方式，可以在蒸汽驱的基础上进一步提高采收率；高温驱油剂的主要作用是提高蒸汽前沿热水带洗油效率，高温泡沫的主要作用是调整蒸汽剖面，增加波及体积，提高热利用率。现场实际应用表明，化学辅助蒸汽驱是高压稠油油藏转蒸汽驱可行的开发方式。

Three-dimensional physical simulation and application of chemistry assistant steam flooding on middle and deep heavy oil reservoir

In Shengli oilfield, steam flooding is impossible to start under the pressure of 5 MPa and the displacement pressure is generally 7 MPa owing to the deep burial depth of heavy oil reservoirs and the impact of edge-bottom water. To further improve the performance of steam flooding, laboratory tests are carried out to increase the reservoir recovery using chemically-assisted flooding approach. A physical simulation study is performed by taking an inverted nine-spot pattern of vertical wells in the Ng5 layer of Gudao district, Shengli oilfield. The magnitude of enhanced oil recovery by simple and chemically-assisted steam flooding is compared for assessing different injection methods with foaming and displacing agents, further to determine the method for site implementation. Laboratory experimental data show that chemically-assisted flooding in the "first adjusting and then flooding" model can further improve oil recovery on the basis of steam flooding. High-temperature displacing agent mainly plays a role in improving the oil-washing efficiency of hot water at the steam frontier, whereas high-temperature foam mainly adjusts the steam profile, increases the swept volume, and improves the thermal efficiency. Field application demonstrates that chemically-assisted steam flooding is a feasible method for the development of high-pressure heavy oil reservoirs.