中高渗油藏空气泡沫封堵与流度控制实验研究

注空气是提高采收率的有效技术;但对于中高渗、非均质油藏,单纯注空气容易引发气窜,加剧老井腐蚀,带来安全隐患。因此,针对此类油藏进行空气驱,需要加入泡沫进行封堵和流度控制。通过室内实验,进行了空气泡沫封堵能力影响因素的敏感性分析,研究了空气泡沫段塞在不同驱替方式和不同驱替速率下的流度控制作用。研究结果表明,温度对空气泡沫稳定性有不利影响;在实验压力范围内,高压可以提高空气泡沫的稳定性;当气液比在1∶1~2∶1之间时,空气泡沫的封堵能力达到最大值;泡沫段塞后气驱,体系阻力因子先增大后减小;泡沫段塞后水驱,在一段时间内体系的阻力因子持续增大;无论是泡沫段塞后气驱还是泡沫段塞后水驱,较高的注入速率会带来较强的封堵能力。

Experimental Study of Air Foam Plugging and Mobility Control in Medium and High Permeability Oil Reservoirs

Air injection is an effective technology to enhance oil recovery. But for mid high permeability, heterogeneous reservoirs, pure air injection is apt to cause gas channeling, bringing corrosion and security risk. Air foam plugging and mobility control is becoming very necessary. In this study, laboratory experiments have been conducted to study the influence factors of air foam plugging ability and the effects of air foam slugging mobility control under different displacement mode and displacement rates. The results indicate that temperature adversely affect the stability of air foams; at a certain pressure range, air foam stability enhanced as the pressure rise; when the gas-liquid ratio is between 1:1 to 2:1, the air foam system has the strongest plugging efficiency. After air foam flooding, the resistance factor of follow-up water flooding increases with rising injection rate; due to rapid gas breakthrough, the resistance coefficient of follow-up air flooding will be increased and then decreased. Whether it is the follow-up gas flooding or water flooding, a high injection rate will bring a strong plugging ability.