渤海X油田聚驱后不同化学驱注入段塞优选及剩余油分布研究

渤海X油田自实施聚合物驱以来,含水上升较快,注聚井的吸水剖面反转现象严重,为改善开发效果,模拟地质油藏特征和开发情况,应用三层非均质平板岩心模型,开展了不同类型化学驱室内实验研究和合理段塞注入方式优选,结果表明:聚表二元驱能够有效改善聚合物驱过程中的剖面反转现象,有效扩大波及体积;优选的段塞注入方式为:0.1 PV(0.25%表面活性剂+2 000 mg/L聚合物)+0.3 PV(0.2%表面活性剂+1 500 mg/L聚合物),优选的聚表二元驱段塞注入方式比聚合物驱提高采收率8.6%。

Optimization of different chemical flooding injection slug after polymer flooding and remaining oil distribution

Since polymer flooding was carried out in Bohai X oilfield, the recovery increased quickly. However, due to the high viscosity of the crude oil, the water-cut after polymer flooding increased rapidly and the profile reversal was serious. To improve the development effect, according to the field geological and reservoir characteristics and development situation, different indoor experiments of chemical flooding and optimization of reasonable mode of slug injection after polymer flooding was carried out by flat core with three heterogeneous layers. The results indicated the polymersurfactant flooding could effectively overcome the profile reversal in the polymer flooding process and expand the sweep volume. The optimal chemical flooding slug was 0.1 PV(0.25% surfactant and 2 000 mg/L polymer) and 0.3 PV(0.2% surfactant and 1 500 mg/L polymer). The optimal polymer-surfactant flooding could improve the recovery ratio by 8.6% than that of polymer flooding.