塔河油田高温高盐苛刻油藏高效起泡剂优选与性能评价

Optimization and performance evaluation of high efficiency foaming agent for high-temperature and high-salinity harsh reservoir of Tahe Oilfield

为进一步提高塔河油田高温高盐油藏的采收率,探索高温高盐油藏泡沫驱油的可行性,通过Ross-Miles法,以泡沫综合值为评价指标优选了耐高温耐高盐起泡剂体系,评价其稳定性、表/界面张力和高温高压下泡沫起泡性能,并通过物理模拟实验研究了泡沫对地层的适应性和驱油效果。实验结果表明:优选的起泡剂为HTS-1两性表面活性剂,高温高盐稳定性好,且能使油水界面张力降低到10-1m N/m数量级;在高压高温下起泡剂的起泡和稳泡性能大幅度提高,且随着压力的增加,起泡性能有进一步增加的趋势;单管岩心物理实验证明泡沫对地层有较广的适应性,在一定地层渗透率范围下,泡沫的封堵性能随渗透率的增大而增强,超过一定渗透率后泡沫的封堵性能下降;驱油实验显示出泡沫能有效封堵高渗层,实现液流转向,并能提高洗油效率,采收率增值达到17%左右。

This paper explores the feasibility of foam flooding for high-temperature and high-salinity reservoir in Tahe Oilfield to improve the oil recovery. The foaming agent was selected by means of Ross-Miles method with the evaluation indexes of foam comprehensive value, and its stability, surface/interfacial tension and foaming properties under high temperature and high pressure were evaluated. Its stratum adaptability and oil displacement efficiency were also evaluated. The results indicate that under the hightemperature and high-salinity conditions in Tahe Oilfield, the optimal foaming agent was amphoteric surfactant HTS- 1, which had satisfactory stability and reduced the oil-water interfacial tension to 10- 1m N/m. It has improved foaming and foam stability at high temperature and high pressure, and the higher the pressure, the better the foam stability. Single core experiment demonstrated that foam flooding has wide stratum adaptability, and the foam plugging performance will be improved with the increase of permeability and be reduced over a certain permeability. Oil displacement experiments show that foam can plug the high- permeability layer,leading to fluid diverting and higher oil displacement efficiency, and increase water flooding recovery by 17%.