鄂西渝东地区东岳庙段页岩气勘探潜力研究

Exploration potential of Dongyuemiao Member shale gas in western Hubei-eastern Chongqing area

鄂西渝东地区下侏罗统自流井组东岳庙段发育厚层灰黑色页岩,钻井揭示气显示良好。文中利用露头、钻井、测井、分析化验、测试等资料,从页岩沉积特征、有机地化特征、储集条件及含气性等方面对东岳庙段页岩进行了系统研究。结果表明:该段以浅湖—半深湖沉积为主,富有机质页岩发育,有机质丰度高,热演化程度适中,含气性较好,具备页岩气形成的有利地质条件;页岩气富集主要受有机质丰度、热演化程度、储集物性及裂缝发育程度等关键因素控制。据此,初步建立了适合本区陆相页岩气有利区优选标准,并根据标准优选区内西北部乐福店—临溪场为东岳庙段陆相页岩气勘探有利区。

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.