Organization
Research Institute of Exploration and Development, Jianghan Oilfield Company, Wuhan 430223, China
College of Resources, China University of Geosciences, Wuhan, 430074, China
College of Geosciences, China University of Petroleum, Beijing 102249, China
Abstract
Dongyuemiao Member of Lower Jurassic Ziliujing Formation in western Hubei-eastern Chongqing area deposits thick dark shales which expose good gas shows. Using the data of outcrop, drilling, logging, analysis and assay, and testing, Dongyuemiao Member shales are studied comprehensively in terms of sedimentation, geochemistry, reservoir condition and gas-bearing properties. Results show that Dongyuemiao Member is dominated by organic-rich shallow lake-semi deep lake facies shales with high organic matter abundance, moderate thermal evolution degree and good gas-bearing properties, and the geological conditions are favorable for shale gas accumulation. The shale gas enrichment is mainly controlled by organic matter abundance, thermal evolution degree, reservoir physical properties and the development degree of fracture. Based on this, the preliminary criteria for favorable continental shale gas zone selection are established. Lefudian-Linxichang in northwestern area is selected as the favorable exploration zone of Dongyuemiao Member continental shale gas according to the criteria.