四川盆地及其周缘页岩气勘探开发现状、潜力与展望

历经10余年的探索与发展,中国南方地区已全面进入中浅层海相页岩气规模效益开发阶段,综合评价四川盆地及其周缘页岩气勘探开发潜力和发展前景,是关乎四川盆地能否建成"天然气大庆"的关键。为了给下一步的页岩气勘探开发提供理论支持,通过系统总结四川盆地上奥陶统五峰组—下志留统龙马溪组页岩气勘探开发理论和成效,分析了中国南方页岩气勘探开发现状与潜力,预判了未来的发展前景。研究结果表明:①川南地区4 500 m以浅五峰组—龙马溪组海相页岩的页岩气资源量为3.7×10~(12)m~3,其中可采储量超过2×10~(12)m~3,具备建成1 000×10~8m~3页岩气年产规模并稳产10年以上的开发潜力,中国石油天然气股份有限公司迄今已累计提交页岩气探明地质储量1.061×10~(12)m~3,并建成百亿立方米年产量页岩气大气区;②渝东北—鄂西地区、川西南—滇东北复杂构造区五峰组—龙马溪组海相页岩的页岩气资源潜力较好,亦具有良好的勘探开发前景;③四川盆地及其周缘具有三套后备页岩气层系,即下寒武统筇竹寺组海相页岩、上二叠统龙潭组海陆过渡相页岩和下侏罗统自流井组陆相页岩,其中筇竹寺组海相页岩在绵阳—长宁拉张槽内优质页岩厚度较大、压力较高、孔隙较发育,是下一步页岩气勘探开发的重点,而川中—川东北地区自流井组大安寨段陆相页岩也具有一定的页岩油气勘探开发潜力。

Status,potential and prospect of shale gas exploration and development in the Sichuan Basin and its periphery

After over ten years of exploration and development, southern China has completely stepped into the stage of scale benefit development of middle-shallow marine shale gas. And a comprehensive evaluation on the shale gas exploration and development potential and development prospect in the Sichuan Basin and its periphery is the key to the construction of "Natural Gas Daqing" in the Sichuan Basin. In order to provide theoretical support for the next shale gas exploration and development, this paper analyzes the status and potential of shale gas exploration and development and forecasts the future development prospect in southern China by systematically summarizing the theories and achievements of shale gas exploration and development in the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation of the Sichuan Basin. And following research results were obtained. First, shale gas resources in the Wufeng Formation-Longmaxi Formation marine shale above 4 500 m in southern Sichuan is 3.7×10¹² m³, among which the recoverable reserves exceed 2×10¹² m³. It has the development potential of constructing a yearly shale gas production scale of 1 000×10⁸ m³ and stablizing production for more than 10 years. So far, PetroChina has submitted 1.061×10¹² m³ proved geological reserves of shale gas in total and constructed the major shale gas province with a yearly production of tens of billions of cubic meters. Second, the Wufeng Formation-Longmaxi Formation marine shale in the northeastern Chongqing-western Hubei area and the southwestern Sichuan-northeastern Yunnan complex structural area have better shale gas resource potential and promising exploration and development prospect. Third, there are three backup series of shale gas strata in the Sichuan Basin and its periphery, i.e., Lower Cambrian Qiongzhusi Formation marine shale, Upper Permian Longtan Formation transitional facies shale and Lower Jurassic Ziliujing Formation continental shale. Among them, the Qiongzhusi Formation marine shale in Mianyang-Changning intracratonic sag is characterized by thicker quality shale, higher pressure and relatively developed pores, and it is the focus for the next shale gas exploration and development. And the Ziliujing Formation Daanzhi Member continental shale in the central-northeastern Sichuan Basin also has a certain potential of shale oil & gas exploration and development.