注入时机对低矿化度表面活性剂驱油的影响

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%。

Research on the Impact of Injection Occasion on Low Salinity Surfactant Flooding

In recent years, the results of core flooding experiments with low salinity water as injection fluid show that low salinity water has a certain degree of enhanced oil recovery. However, the effect of the low salinity surfactant (LSS) injection occasion on the oil displacement has not been studied. Here, the low salinity water was combined with surfactant to carry out the core flooding experiment. The anionic surfactant was chosen to achieve a lower oil-water interfacial tension (IFT) in a low salinity environment of 2000 mg/L NaCl. The experimental results show that the injection occasion has a great influence on the oil recovery, water cut, injection pressure and pressure reduction rate. The earlier the injection occasion, the higher the ultimate oil recovery. When the high salinity water flooding reaches the water cut of 60.5%, 81.5%, 98.1%, the LSS flooding will increase the oil recovery by 38.9%, 25.3%, 15.7%, and the final oil recovery was 74.3%, 67.8%, 65.1%, respcetively. The maximum difference of the final oil recovery of different injection occasion is 9.2%. The earlier the injection occasion, the lower the pressure reduction rate, and the maximum difference in the pressure reduction rate is 33.1%. The oil recovery of LSS flooding is higher than low salinity water flooding, which shortens the oil displacement time.