Prospect Analysis of Shale Gas Resource Exploration in the Lower Silurian Longmaxi Formation, Southeastern Margin of the Sichuan Basin, China

Abstract

In order to understand the sedimentary characteristics of shale and prospects of shale gas exploration in the lower Silurian Longmaxi Formation northern of Guizhou Province, outcrop and core observations, thin sections, X-ray diffraction analysis and other means are used. Studies show that the thickness of Longmaxi formation shale is generally large, range from 20m to 200m, mainly develop in the water shelf. The mineral mainly compose of detrital quartz and clay minerals, and five lithofacies can be identified: black shale, silty shale, carbonaceous shale, calcareous shale and argillaceous siltstone. Longmaxi shale kerogen type is mainlyIand II, and Ro value is average of 1.87%, mainly in the mature - over mature stage. In addition, the TOC content and gas content of Longmaxi shale is high, what’s more, these two parameters have good positive correlation. Compared with the Barnett shale, both of them have some similarities in the development environment shale, shale thickness and type of organic matter and TOC content, while, Longmaxi shale is deeply buried and post-destruction more intense. Longmaxi shale sedimentary environment is stable, high shale thickness and stable distribution, good quality source rocks and high brittle mineral content, which has meet the basic parameters of shale gas exploration and development, and has a large shale gas exploration potential in study area.