页岩孔隙结构表征方法新探索  

A new approach to the characterization of shale pore structure

作　　者：孙文峰[1] 李玮[1] 董智煜 闫铁[1] 李悦[1] 李世昌[1] 

机构地区：[1]东北石油大学石油工程学院,黑龙江大庆163318 [2]中国石油大庆油田有限责任公司采油三厂,黑龙江大庆163318

出　　处：《岩性油气藏》2017年第2期125-130,共6页Lithologic Reservoirs

基　　金：国家自然科学基金项目"页岩油气高效开发基础理论研究"(编号:51490650);"十三五"国家重大科技专项"大型油气田及煤层气开发"(编号:2016ZX05020-002)联合资助

摘　　要：孔隙结构对页岩储层的储集性能、渗流能力和页岩气产能具有十分重要的影响,是页岩储层评价的核心内容。为全面、直观地展现页岩储层孔隙结构的空间特征,选取川南龙马溪组页岩为研究对象,先运用MATLAB自编程序识别扫描电镜(SEM)二值图像的方法,测得不同孔隙面积与相应的面孔率数值,拟合得到了岩样的面孔率函数;再利用积分几何理论建立了面孔率函数与孔隙度函数之间的换算模型,计算得到了岩样的孔隙度与孔径之间的函数关系,并据此对龙马溪组页岩孔隙结构进行了定量分析。结果表明:川南龙马溪组页岩岩样的孔径主要为1~50 nm,孔隙度峰值出现在孔径为13 nm处,中孔是孔隙的主体,占总孔隙空间的93.7%。与高压压汞实验和低温氮气吸附实验结果比较,SEM图像观测法所得结果可靠,验证了该方法的可行性。该方法不仅适用于页岩储层,也适用于其他致密储层。The pore structure is the core content of shale reservoir evaluation, which has important influence on the reservoir performance, seepage capacity and shale gas productivity. In order to show the spatial characteris- tics of pore structure in shale reservoir comprehensively and visually, MATLAB programming was used to identify scanning electronic microscope （SEM） binary image of samples from Longmaxi shale in southern Sichuan Basin, by which different pore area and corresponding plane porosity were obtained, and the plane porosity func- tion was fitted. Then, the conversion model between the 2D porosity function and the porosity function was established by applying the integral geometry theory. The function relationship between the porosity and the pore size was calculated and the shale pore structure of the Longmaxi Formation was analyzed quantitatively. The results show that the pore size ranges from 1 to 50 nm, 13 nm corresponds to the MAX porosity, the volume fraction of mesopores is the most （93.7%）. Compared with the results of high pressure mercury intrusion and low temperature nitrogen adsorption experiments, the result obtained by SEM image method is reliable, which veri- fies the feasibility of this method. The method is applicable for shale and tight reservoirs.

关 键 词：页岩气 页岩孔隙 孔隙度 孔隙结构表征 积分几何 

分 类 号：TE132.2[石油与天然气工程—油气勘探]