低渗透油藏CO_2驱微观波及特征  

Microscopic sweeping characteristics of CO_2 flooding in low permeability reservoirs

作　　者：李南 田冀 谭先红 刘新光 

机构地区：[1]中海油研究总院,北京100028

出　　处：《断块油气田》2015年第2期237-239,共3页Fault-Block Oil & Gas Field

基　　金：国家重点基础研究发展计划(973计划)项目"CO2驱渗流力学理论"(2011CB707305-005);国家科技重大专项专题"海上油田丛式井网整体加密及综合调整技术"(2011ZX05024-002-006)

摘　　要：基于两相驱油机理,文中建立了考虑扩散的微观两相渗流数学方程,采用二维从简单到复杂的孔隙喉道模型,分析了均匀、非均匀孔隙喉道不考虑对流扩散和非均匀孔隙喉道考虑对流扩散条件下的微观波及特征,总结了微观剩余油模式以及润湿性对微观波及效率的影响,进一步认识了CO2在低渗透油藏中的微观渗流规律。研究结果表明:对流扩散提高了CO2驱微观波及体积;孔隙喉道内部剩余油分布模式主要为柱状、楔形和膜状;随着润湿角的增加,微观波及体积明显降低,因而可以通过改变储层润湿性来提高低渗透储层微观波及体积。Microscopic two-phase seepage mathematical equation considering diffusion theory is built based on the mechanism of two-phase displacement in this paper.With simple and complex 2D pore and throat models,the microscopic sweeping characteristics under three different conditions are analyzed,including the uniform pore throat,the non-uniform pore throat without considering convection and diffusion and the non-uniform pore throat considering convection and diffusion.The effects of microscopic residual oil distribution patterns and different wettability on microscopic sweeping efficiency are summarized and the mechanism of microscopic seepage for CO2 flooding in low permeability reservoir is further understood.The results show that convection and diffusion raise the microscopic swept volume of CO2 flooding; the main distribution patterns of residual oil are prismatic,wedge-shaped and filmy; microscopic swept volume decreases sharply while wetting angle increases.The microscopic swept volume for low permeability reservoir can be raised by improving the reservoir wettability.

关 键 词：低渗透油藏 CO2驱 微观波及特征 润湿性 对流扩散 渗流模型 

分 类 号：TE348[石油与天然气工程—油气田开发工程]