注入时机对低矿化度表面活性剂驱油的影响

The Impact of Injection Occasion on Low Salinity Surfactant Flooding

近年来,针对低矿化度水为注入液的研究结果表明,低矿化度水在一定程度上有提高采收率的作用。相比于低矿化度水驱,低矿化度表面活性剂驱在提高采收率方面具有更大的优势。然而,低矿化度表面活性剂注入时机对驱油的影响缺乏相关研究。选择一种能在低盐度环境下获得油水超低界面张力的阴离子表面活性剂KPS,在不同转注时机下进行低矿化度表面活性剂驱油实验。结果表明,注入时机对采收率、含水率、注入压力及降压率都有较大影响。注入时机越早,最终采收率越高,当高矿化度水驱至含水率分别为60.5%、81.5%、98.1%后转注低矿化度表面活性剂,采收率增值为38.9%、25.3%、15.7%,最终采收率为74.3%、67.8%、65.1%;注入时机越早降压率越低,降压率最大差值为33.1%。

In recent years,studies on low salinity water as an injection fluid show that low salinity water has a certain degree of enhanced oil recovery.Low salinity surfactant(LSS)flooding has a greater advantage in terms of enhanced oil recovery than that of low salinity water flooding.However,less attention was paid to the effect of injection occasion for the LSS on the oil displacement.In this experiment,an anionic surfactant karamay petroleum sulfonate(KPS)that can decrease oil-water interfacial tension to 10-3 mN·m-1 was chosen.Core flooding experiment with LSS was carried out at different injection occasions.The experimental results show that the injection occasion had a great influence on the oil recovery,water cut,injection pressure,and pressure reduction rate.The ultimate oil recovery was decreased with injection occasion.When the high salinity water flooding attained to water cut of 60.5%,81.5%,98.1%,the LSS was transferred,and the oil recovery was 38.9%,25.3%,15.7%,and the ultimate oil recovery was 74.3%,67.8%,65.1%,respectively.The pressure reduction rate was increased with the injection occasion,and the maximum difference in the pressure reduction rate was 33.1%.