川东龙马溪组页岩应力敏感实验研究  

Experimental Study on Stress Sensitivity of Longmaxi Formation Shale in Eastern Sichuan

作　　者：姜宇玲 关富佳[1] 胡海燕[1] 

机构地区：[1]长江大学非常规油气湖北省协同创新中心,湖北武汉430100 [2]长江大学石油工程学院,湖北武汉430100

出　　处：《西安石油大学学报（自然科学版）》2016年第6期80-86,共7页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：国家自然科学基金"川东龙马溪组页岩气成藏机理及其主控因素"(编号:41472122);非常规油气湖北省协同创新中心创新基金"基于复杂结构井的页岩气产能研究"(编号:HBUOG-2014-3)

摘　　要：应用PDP-200脉冲衰减法渗透率仪对涪陵页岩气藏产气层系龙马溪组页岩露头进行渗透率应力敏感性评价,采用定围压-降内压和定内压-升围压的方法对同一块具有水平层理缝的岩样进行渗透率测试。结果表明:随着作用在页岩上的有效应力的增大,页岩测试渗透率呈指数规律递减,递减过程按递减指数大小分为2段,分别体现了页岩裂缝渗透率的应力敏感性和页岩基质渗透率的应力敏感性;同时,定围压测试较定内压测试页岩渗透率不能马上恢复,存在一定的滞后效应,并且定内压测试时得到的裂缝闭合压力要比定围压测试时有所降低。龙马溪组页岩露头表现出双重介质特征,并且在内压卸载时造成了无法恢复的渗透率塑性损伤。The stress sensitivity of the permeability of the shale outcrop samples of Longmaxi formation in eastern Sichuan with horizon- tal bedding crack was evaluated in order to effectively develop shale gas and correctly evaluate the production capacity of shale gas in China. The permeability of cores was measured using PDP-200 permeability meter, and experimental plans include decreasing inner pressure under constant confining pressure and increasing confining pressure under constant internal pressure. The experimental results show that, the tested permeability of the core exponentially declines, and the descending process is divided into two sections according to the decreasing index,which reflect the stress sensitivity of shale crack permeability and shale matrix permeability separately;compared with constant internal pressure test, there is a permeability hysteresis effect in constant confining pressure test, and the crack closure pressure in constant internal pressure test is less than that in constant confining pressure test. The shale outcrop samples of Longmaxi formation have dual-porosity characteristic, and there is unrecoverable damage of permeability when inner pressure is decreasing.

关 键 词：龙马溪组页岩 双重介质 应力敏感性 渗透率伤害 

分 类 号：TE319[石油与天然气工程—油气田开发工程]