注有机极性气体开采稠油技术

A polar organic gas injection technology for heavy oil production

针对储层薄、埋藏深的稠油油藏开发难度大及开采成本高的问题,在注溶剂萃取稠油技术(VAPEX)的基础上,提出向稠油油藏注入一种低饱和蒸汽压的有机极性气体PE提高采收率的采油技术。利用相态观察及黏度测定两种方法研究了该气体与稠油在气态和液态两种情况下的降黏效果。另外,还对比了该气体与VAPEX中常用烃类气体LPG对稠油降黏及萃取效果。实验结果表明:该气体在原油中具有很好的溶解性,能大幅度降低原油黏度;和LPG与稠油作用不同,该有机气体在液态状态下能大量分散稠油中的沥青,形成一种低密度低黏度混合相。现场应用表明注入该气体的措施井增产效果明显,因此,该注气技术可适用于一些埋藏深、油层薄、渗透性差和黏度高的稠油油藏。

Regarding the problems of difficult exploitation and high development cost in deeply buried heavy oil reservoirs with thin net pay, this paper integrates the advantages of VAPEX and proposes a new EOR technology for such reservoirs with injecting a low saturated vapor pressure polar organic gas PE. The viscosity reduction effect of this polar gas under two phases of gas and liquid were studied through phase observation experiments and viscosity measurement. Furthermore, its performance on viscosity reduction and oil displacement has been compared with LPG, which is commonly used in VAPEX. The research results indicate gaseous PE has good solubility in heavy oil and could dramatically reduces heavy oil viscosity. Liquid PE forms a low density and low viscosity phase by dis- solving more and more bitumen in crude oil, which is better than the solution capability of LPG. The field pilot has shown that injection the organic polar gas can greatly increase the oil production of simulated well. The technology is practical and worthwhile large-scale implementation for deeply buried heavy oil reservoirs with poor qualities： thin net pay and low permeability.