国外CO_2驱流度控制进一步扩大波及体积方法

Methods of Improving Sweep Volume by Mobility Control for CO_2 Flood in Foreign Countries

CO_2驱油是一种有效的提高采收率方法,矿场成功应用已有60多年。理论上微观驱油效率接近100%,但相对原油,CO_2的低黏度低密度与储层的非均质性导致的黏性指进和重力分离两大典型问题大大降低了气体波及系数。本文综述了国外各种流度控制方法,包括气水交替、聚合物直接稠化CO_2、CO_2泡沫驱、气-化学剂联合方法及气体辅助重力泄油,简要介绍了CO_2驱扩大波及体积的其他方法,分析了每种方法的机理及优缺点,力图为我国CO_2驱油进一步扩大波及体积这一难题积累先进做法和经验。

CO2 flood had been used successfully to recover crude oil from reservoirs over 60 years. Theoretically microscope displacement efficiency was approaching 100%. However, low viscosity and density of CO2 compared with crude oil and reservoir heterogeneity resulted in viscous fingering and gravity segregation, which caused poor sweep efficiency. Different methods of mobility control in foreign countries were reviewed including water-alternating-gas, direct thickening CO2 by polymer, CO2-foam flooding, combined gas with chemicals and gas assisted gravity drainage. Other methods about improving sweep volume had also been introduced briefly. Mechanisms of these methods and their advantages and disadvantages were analyzed. The goal was to gain advanced avvroaches and experience for further improving sweep volume for CO2 flood in China.