测试页岩基质渗透率不应考虑扩散影响的思考  

Reflection on the issue that shale matrix permeability test should not consider the effect of diffusion

作　　者：何家欢[1,2,3] 

机构地区：[1]中国石油西南油气田分公司,四川成都610051 [2]四川省页岩气评价与开采重点实验室,四川成都610051 [3]西南石油大学,四川成都615000

出　　处：《特种油气藏》2015年第4期147-150,158,共4页Special Oil & Gas Reservoirs

基　　金：国家"973"计划项目"南方海相典型区块页岩气开发理论与技术适应性研究"(2013CB228006);国家科技重大专项"南方海相页岩气开采试验"(2011ZX05018-006)

摘　　要：国内不少学者尝试用柱塞样测试页岩渗透率,结果往往较常规储层渗透率大。在一些外文文献已经认定页岩基质渗透率很小的情况下,一些学者没有认识到此时实验的柱塞样已产生了微裂缝,从而导致测试结果偏大。选择用"扩散"这一概念回避上述事实,并认为页岩气在基质中是以扩散形式运移的,测页岩基质渗透率时应考虑扩散的影响。从渗透率概念入手,分析了压力脉冲衰减法、粉碎法测页岩基质渗透率等方法数学模型中渗流微分方程的适用条件。同时,从扩散的定义入手,结合页岩气开发的自身特点,对国内外普遍认为气体在页岩中以扩散方式运移的观点提出了质疑,从而提出测试页岩基质渗透率时不应考虑扩散影响的观点。Many scholars in China tried to test shale gas permeability by using plug samples,but the results were always higher than conventional reservoir permeability. The fact is that it is confirmed that shale matrix permeability is extremely low in many foreign literatures. But the scholars did not realize that micro- fractures were produced in test plug samples,which resulted in higher test permeability. They used the conception of'diffusion'to explain it and believed that,shale gas migrates in matrix in the form of diffusion and the diffusion shall be considered during shale matrix permeability tests. In this paper,starting from the concept of permeability,the author analyzed the applicable conditions of flow differential equations in mathematical models of shale matrix permeability by use of pressure pulse decay test and crushed permeability test. Meanwhile,starting from the concept of diffusion,considering the features of shale gas development,the author questioned the generally accepted opinion of shale gas migrating in the form of diffusion and believed that diffusion should not be considered during shale matrix permeability tests.

关 键 词：页岩 基质 渗透率 扩散 

分 类 号：TE312[石油与天然气工程—油气田开发工程]