四川盆地涪陵焦石坝地区保存条件差异性分析

Preservation condition differences in Jiaoshiba area, Fuling,Sichuan Basin

李金磊 尹成 王明飞 杨莎莎 刘晓晶 陈超

LI Jinlei YIN Cheng WANG Mingfei YANG Shasha LIU Xiaojing CHEN Chao

1. 西南石油大学 地球科学与技术学院, 成都 610500; 2. 中国石化 勘探分公司, 成都 610041

1. School of Geoscience and Technology, Southwest Petroleum University, Chengdu, Sichuan 610500, China; 2. SINOPEC Exploration Company, Chengdu, Sichuan 610041, China

保存条件是页岩气富集高产的关键。涪陵焦石坝地区的页岩气保存条件在平面上有一定的差异性，通过岩心观察、FMI测井解释以及地震综合解释预测等手段，对其差异性进行分析。后期构造运动的差异改造是不同构造单元保存条件差异的主要原因，具体表现为裂缝发育规模的差异、裂缝封闭性的差异、断裂的叠加效应影响以及引起的地层变形程度差异。构造运动形成的断裂规模（断距、延伸长度、断开层位、裂缝密度）以及断裂的性质决定了构造单元基本的保存条件；最大主应力与裂缝走向之间的锐夹角关系影响着裂缝的封闭性，锐夹角越大，封闭性越好；断裂系统的纵向叠加和横向叠加效应会形成立体的渗流通道，打破原有的封闭环境，引起页岩气的强烈扩散，值得高度重视，同时地层倾角作为构造作用强度的直观体现，页岩气顺层理方向上的扩散作用随倾角增大而逐渐增强，目标优选时尤其是针对复杂构造区需要考虑。

The preservation condition is critical to the enrichment and high yields of shale gas. Exploration and development of the Fuling shale gas indicated that the preservation condition changes horizontally in the Jiaoshiba area. This change was analyzed using core observations, FMI logging interpretations and comprehensive seismic interpretations. Different transformations of structure units after later tectonic movements explained the diversity of preservation condition. Specifically, the differences are related to fracture scale, closure, the effect of fracture superposition and the formation deformation. The size of the fault (fault distance, extension length, offset, fracture density) and the fault properties determine the basic preservation condition of structural units. The sharp angle relationship between the maximum principal stress and the direction of the fracture affects the sealing of the fracture. The larger the sharp angle, the better the sealing property. The vertical and lateral superposition of the fracture system will form a three-dimensional seepage channel, which has a great influence on the original closed environment of shale gas, and causes strong dispersion of shale gas. This causality is worthy of attention. At the same time, the dip angle of the formation is a direct reflection of the extent of the tectonic movement. As the diffusion effect in the parallel stratification direction of shale gas increases with the inclination angle, which increases gradually, it is necessary to analyze the dip angle when choosing the prime target especially in complex structural areas.

国家科技重大专项“页岩气区带目标评价与勘探技术”（2017ZX05036）和中国石化基础研究项目“四川盆地深层页岩气地震预测技术研究”（P18074-1）联合资助。

https://doi.org/10.11781/sysydz201903341