基于构造差异的页岩孔隙结构与吸附能力表征

Characteristics of shale pore structure and adsorption capacity based on tectonic difference

于雯汀,吴亚红

中海油田服务股份有限公司油田生产事业部，天津 300451 中国石油大学（北京）石油工程学院，北京 102249

Production Optimization Division, China Oilfield Services Limited, Tianjin 300451, China College of Petroleum Engineering,China University of Petroleum, Beijing 102249, China

运用场发射扫描电镜（FE￣SEM）和N2/CO2等温吸附方法，文中对黔北地区不同构造区五峰组—龙马溪组页岩的孔隙特征进行表征，并且基于构造差异深入分析了其孔隙结构及甲烷吸附能力。研究表明：相比于高陡构造区，低缓构造区孔径以双峰分布为主，并且发育较多的微裂隙有机质孔隙、与黏土矿物紧密结合的有机质孔隙以及粒间孔隙，而刚性矿物格架内的有机质微孔几乎不受构造条件影响，其发育特征仅随总有机碳质量分数（TOC）改变。低缓构造区微孔、中孔、大孔的体积均大于高陡构造区，表明低缓构造区具有更大的孔隙空间和游离气储存能力。另外，甲烷等温吸附实验表明，构造差异对甲烷吸附能力无显著影响，有机质丰度和保存条件是储层高产的先决条件。

The pore characteristics of Wufeng-Longmaxi Formation in different structural areas in northern Guizhou were characterized by FE-SEM and N2/CO2 isotherm adsorption, and the shale pore structure and adsorption capacity of the were analyzed based on the difference in tectonic conditions. The research shows that comparing with the steep structural area, the pore size distribution in the low-gentle structure zone is dominated by bimodal peaks. And there are are more intergranular pores, clay minerals organic pores and fissure-type pores developed, while the organic micropores in the rigid mineral framework are almost unaffected by tectonic conditions, and their development characteristics only change with TOC. The micropore, mesopore and macropore volumes of the low-gentle structure area are all bigger than that of the steep structure area, which indicating the low-gentle structure area has larger pore space and free gas storage ability. In addition, the methane adsorption isotherm experiment shows that the difference in tectonic condotions has no significant effect on the methane adsorption capacity, organic matter abundance and preservation conditions are the prerequisites for high reservoir production.

10.6056/dkyqt202201016