• 责任者：Zheng Rongcai (State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation ; Chengdu University of Technology ; Chengdu 610059 ; China) ; He Long
• 刊名：Natural Gas Industry
• 出版年：2013
• 卷期：33(12)
• 关键词：页岩气 ; shale gas ; 油气藏形成 ; reservoir formation ; 四川盆地 ; Sichuan Basin
• 页码：p.30-40
• 图表：8 illus., 3 tables, 28 refs.
• 分类号：1003
• issnNo：ISSN1000-0976
• isbnNo：CN51-1179/TE

     Recently, moderate to high rate of oil/gas flows were tested in several wells in the Ddanzhai member black shale with thin shelly limestone interbeds of lake facies of the Lower Jurassic Ziliujing Fm in the southern part of Wanxian syncline in the eastern Si- chuan Basin. In order to investigate the accumulation conditions and potentials of shale gas/oil in the Ddanzhai member, this paper analyzed its petroleum geologic conditions as follows. First, the Ddanzhai member was deposited in a fresh lake environment. Four subfacies were identified, including lakeshore, shallow lake, slope and deep to semi deep lake. They correspond to a complete lake transgressive-retrogressive cycle consisting of four sedimentary system tracts, namely lowstand system tract, transgressive system tract, early highstand system tract and late highstand system tract. Second, the isochronal stratigraphic framework crossing each subfacies zones controls the conditions of indigenous shale gas/oil accumulation in the Da~anzhai member. Third, the condensed sec- tion in the lake transgressive system tract and the shallow lake beach margin, slope and semi-deep lake suhfaeies in the early high- stand system tract are favorable shale gas/oil reservoir facies belts. The reservoirs are combinations of carbonaceous shale and argillaceous shelly limestone interbeds instead o{ a single rock type. Based on these understandings, five criteria including TCK2, thermal maturity, shale thickness, burial depth and shale brittleness, in combination with shale composition and fracture development, were used to evaluate the Dd anzhai shale gas/oil plays. In conclusion, the Da~anzhai member is believed to have favorable geologic conditions {or shale gas/oil accumula- tion in the eastern Sichuan Basin, thus can be taken as one of the primary exploration targets for unconventional hydrocarbon resources.