The Basic Characteristics of the Shale Gas in Wufeng-Longmaxi Formation, Southwest Sichuan Basin of China——Taking Moshigou Section in Leibo Country as an Example

Zhiqiang Bai¹, Shugen Liu^1,3, Chao Luo¹, Sun Wei², Ran Bo^2,3, Yang Di¹, and Jiawen Qiu^1
1College of Energy Resources, Chengdu University of Technology, Chengdu, Sichuan, China
²School of Geosciences, Chengdu University of Technology, Chengdu, Sichuan, China
³State key laboratory of Oil and Gas reservoir geology and exploitation (CDUT), Chengdu, Sichuan, China

Black organic-rich mudrock of Wufeng-Longmaxi formation, serving as good hydrocarbon source rocks before, has been widely considered to be a potential shale gas reservoir in the Southwest Sichuan Basin nowadays, the Upper Yangtze. The former studies are not enough on the relationship of the several parameters of the shale. And this hinders the further analysis of shale gas target horizon of reservoir characteristics. A typical characterisation of the shale gas reservoir was determined based on a series of experiments of outcrop samples, including organic geochemical, mineralogical, nitrogen adsorption and adsorbed gas experiments, to explore the shale characteristics of reservoir physical property and hydrocarbon content. The achievements of the experiments are coming as follows: (1) The effective thickness of the shale is 42.2 meters, the average parameters are: organic carbon content 2.42%, the maturity 2.14%, and the content of quartz mineral 45.47%. (2) Positive correlation between organic carbon content and quartz content, but negative correlation between organic carbon content and clay content. (3) Positive correlation between average 14.72% BET surface area and organic carbon content, quartz content. (4) The average of Gas content up to 2.21 cm³ / g (7.05 MPa) which is positive with organic carbon content, BET surface area and quartz content. Analysis of the data demonstrates that the Wufeng-Longmaxi formation has the greatest potential for gas production due to higher thermal maturity, total organic carbon (TOC), well-developed nanometer pores and Gas content. Higher TOC content, more nanometer pores, higher the gas content, and at the same time, higher brittleness mineral content, it is more favorable for shale gas fracturing exploiting.

AAPG Datapages/Search and Discovery Article #90180©AAPG/SEPM/China University of Petroleum/PetroChina-RIPED Joint Research Conference, Beijing, China, September 23-28, 2013