致密油藏微量气气水交替注入参数的设计方法  

Experimental design and parameter optimization of trace gas-altering-water in tight oil reservoir

作　　者：徐大融[1] 李相方[1] 李元生[1] 

机构地区：[1]中国石油大学(北京)石油工程教育部重点实验室,北京102249

出　　处：《油气地质与采收率》2016年第2期103-107,114,共6页Petroleum Geology and Recovery Efficiency

基　　金：陕西省科技重大专项"提高延长油田主力油层开发效果系统工程关键技术研究"(2011KTZB-04-05)

摘　　要：致密油藏中孔喉狭小,且非均质性很强,油水两相间形成较高的毛管阻力,水驱过程中水相将首先突破毛管压力较小的大孔道。随着大孔道的连续性被突破,一个水窜通道将逐渐形成,之后注入的水将沿着水窜通道流动而失去驱油作用,若储层中存在微裂缝该现象更明显。研究致密油藏储层孔隙结构及水驱过程可能的毛管压力分布,针对气水交替中油气水毛管压力压降特征,提出了注入微量气段塞及大量水段塞调堵致密油藏天然裂缝及较大孔隙的气水交替法,设计了一种新的微量气注入实验,并且从注入强度、注入周期和注入次数3个方面进行优化,预测采收率的变化。研究表明,采用微量气气水交替法对致密油藏水驱水窜后提高开发效果是有效的。Tight oil reservoir has narrow and small pore throat and strong heterogeneity. There is a high capillary resistance between oil and water two phases,so the water phase will firstly break through the pore throat with the lowest capillary force in the water flooding process. Along with the continuous breakthrough of the larger pores,a water channel will be formed gradually,and then the injected water will flow along the channel and lose the effect of oil displacement. This phenomenon will be more obvious when there is a series of micro-cracks in the reservoir. Pore structure of reservoirs and possible capillary force distribution during the water flooding in the tight oil reservoir were researched. According to pressure drop features of oil-gas-water capillary force during WAG,a new WAG method was proposed using the injection of trace gas slug and large amount of water slug to plug the natural cracks and larger pores in the tight oil reservoir. A new trace gas injection experiment was designed,and the injection intensity,injection cycle and injection times were optimized. The changes of the recovery efficiency were observed. The results show that trace gas-altering-water method is effective for enhancing development effect in the tight oil reservoir after the formation of water channel in water flooding.

关 键 词：致密油藏 气水交替 毛管压力 微量气 注入周期 注入量 

分 类 号：TE348[石油与天然气工程—油气田开发工程]