低矿化度水/表面活性剂复合驱提高采收率技术

Alternative injection of low salinity water/surfactant to improve recovery

张建国

ZHANG Jianguo

延长油田股份有限公司子长采油厂，陕西 延安 717300）

Zichang Oil Production Plant, Yanchang Oilfield Co., Ltd., Yan′an 717300, China)

为进一步提高低渗砂岩油藏水驱后的采收率，结合低矿化度水驱和表面活性剂驱的特点，提出了低矿化度水/表面活性剂复合驱提高采收率技术，并通过室内实验对不同矿化度水以及表面活性剂溶液的综合性能进行了评价。结果表明：低矿化度水（3 000 mg/L）条件下，质量分数为0.5%的TBS￣3表面活性剂溶液仍能达到超低界面张力范围，具有良好的界面活性；表面活性剂溶液的矿化度越低，原油/溶液以及岩石/溶液之间的Zeta电位值越小，pH值越高；随着表面活性剂溶液矿化度的逐渐降低，表面活性剂TBS￣3在岩心中的吸附损失率增大，岩心入口端面的接触角减小，亲水性增强。岩心模拟驱油实验结果表明，使用低矿化度水/表面活性剂交替注入时的最终采收率可以达到50.3%，明显高于高矿化度水/表面活性剂的40.6%。这说明低矿化度水驱与表面活性剂驱相结合，能够发挥出更好的驱油效果。

In order to further improve the recovery of low permeability sandstone reservoir after water flooding, combined with the characteristics of low salinity water flooding and surfactant flooding, a low salinity water/surfactant composite flooding technology for enhancing oil recovery was proposed. The comprehensive properties of different salinity water and surfactant solutions were evaluated by laboratory experiments. The results show that, under the condition of low salinity water 3,000 mg/L, the 0.5% TBS?鄄3 surfactant solution can still reach the range of ultra?鄄low interfacial tension value and has a good interfacial activity. The lower the salinity of the surfactant solution, the smaller the Zeta potential value between the crude oil/water solution and the rock/water solution, the higher the pH value. With the decrease of the salinity of the surfactant solution, the loss rate of the surfactant TBS?鄄3 in the core of the rock gradually increases, the contact angle of the entrance face of the core gradually decreases, and the hydrophilicity increases gradually. The experimental results show that the final recovery can reach 50.3% when the low salinity water/surfactant is used alternately, obviously higher than 40.6% of the high salinity water/surfactant. It shows that low salinity water flooding can be combined with surfactant flooding to produce better oil displacement effect.

10.6056/dkyqt201905014