水驱后凝胶与表活剂交替注入驱油效果

针对裂缝性低渗透油藏注入水易沿裂缝突进、含水上升快、水驱效果不理想的情况,开展了水驱后凝胶与表活剂交替注入方式提高采收率室内实验研究。通过室内凝胶体系成胶特性和稳定性评价,筛选出与实际油藏区块注入水配伍的凝胶体系。选择甜菜碱两性表面活性剂用于活性剂驱,开展了双管并联岩心体系驱油效果研究。研究结果表明:凝胶与表活剂交替注入可明显提高注入压力,该体系的采收率平均值为12.03%,低渗岩心的采收率略高于高渗透岩心采收率。与表活剂驱、聚合物与表活剂交替注入相比,驱油效果更好,可以作为裂缝性低渗透油藏水驱后进一步提高采收率的技术。

Oil Displacement Effect of Alternative Injection of Gel and Surfactant After Water Flooding

Because injected water always goes along fractures, water content rises rapidly and the effect of water flooding is not ideal in naturally fractured low-permeability reservoirs, indoor experimental study on alternating injection of gel and surfactant to improve the recovery rate after water flooding was carried out. Through evaluation on gelling properties and stability of gel systems, the gel system matched with the injected water was screened out. Betaine amphoteric surfactant was used for surfactant flooding. Study on oil flooding efficiency of double-tube parallel core system was carried out. The results show that the alternative injection method of gel and surfactant can obviously improve the injection pressure, mean value of the system recovery rate can reach to 12.03%, the recovery rate of low permeability core is slightly higher than that of high permeability core. Compared with surfactant flooding, the alternative injection of polymer and surfactant has better oil flooding efficiency; it can be used to improve oil recovery of fractured low permeability reservoirs after water flooding.