【摘要】 四川盆地是我国天然气资源富集盆地之一，在其北部围绕晚二叠世“开江-梁平海槽”已发现了万亿立方米天然气聚集带。近年来，油气地质基础研究结果表明“开江—梁平海槽”起始于中二叠世茅口期，其台地边缘带连续获得十余口超百万立方米天然气钻井新发现，呈现出茅口组具备常规-非常规一体的油气勘探前景，是盆地目前海相全领域油气勘探的重要层系。为了进一步明确四川盆地茅口期构造-沉积分异作用，深入茅口组地质规律的认识，基于最新的井震资料，开展了四川盆地茅口组沉积环境分析和岩相古地理重建工作，指出了该海相全领域油气勘探前景。研究结果表明：(1)上扬子地区茅口组发育开阔台地、台地边缘滩、深水陆棚、淹没台地、台内盆地等沉积相；(2)茅口组沉积早期—中晚期发生了构造-沉积分异转换，由早期稳定地貌背景的台-棚弱分异向中期同沉积断裂控制的台-槽中分异转换，再向晚期大面积隆升暴露主导的槽-隆强分异转换；(3)构造-沉积分异转换造就了茅口组海相全领域油气勘探潜力，茅口组沉积早期发育海侵作用成因的富有机质瘤状灰岩储层，茅口组沉积中期发育环深水陆棚台缘滩相灰岩储层/白云岩储层及深水富有机质硅质泥灰岩储层，茅口组沉积晚期发育富有机质硅质页岩储层和岩溶储层。结论认为，该认识对于上扬子地区茅口组油气勘探具有指导意义，同时在四川盆地茅口组常规领域具有隐蔽性强的薄储层特性，非常规领域具有超高有机质富集的优势，该领域是一个新的万亿立方米天然气全领域勘探层系。更多还原

【Abstract】 The Sichuan Basin is one of the basins rich in natural gas resources in China. In its northern part, a trillion-cubic-meter natural gas accumulation belt has been discovered around the Late Permian "Kaijiang-Liangping Trough". The recent basic studies of petroleum geology show that the "Kaijiang-Liangping Trough" is originated in the Maokou period of the Middle Permian. More than ten new discoveries of natural gas wells with a capacity of over one million cubic meters have been continuously made in the marginal zone of its platform, indicating that the Maokou Formation has a promising prospect of integrated conventional and unconventional oil and gas exploration, and is currently an important layer for all-round marine oil and gas exploration in the Sichuan Basin. In order to further clarify the tectonic-sedimentary differentiation in the Sichuan Basin during the Maokou Period and further understand the geological laws of the Maokou Formation, this paper analyzes the sedimentary environment of the Maokou Formation in the Sichuan Basin and reconstructs the lithofacies paleogeography, based on the latest logging and seismic data. In addition, the prospect of this all-round marine oil and gas exploration is predicted. The following results are obtained. First, in the Upper Yangtze region, the sedimentary facies developed in the Maokou Formation includes open platforms, platform marginal banks, deepwater continental shelves, flooded platforms and intraplatform basins. Second, during the early to the middle and late stages of the Maokou period, a tectonic-sedimentary differentiation transition occurred from the platform-shelf weak differentiation in the geomorphologic setting of carbonate gentle slope in the early stage to the platform-trough moderate differentiation controlled by synsedimentary faulting in the middle stage, and then to the trough-uplift strong differentiation dominated by extensive uplift and exposure in the late stage. Third, the tectonic-sedimentary differentiation transformation endows the Maokou Formation with the all-round marine oil and gas exploration potential. In the early stage of the Maokou period, organic-rich nodular limestone reservoirs of transgressive origin were developed. In the middle stage, platform marginal bank facies limestone/dolomite reservoirs around the deepwater continental shelf as well as deepwater organic-rich siliceous marl reservoirs were developed. In the late stage, organic-rich siliceous shale reservoirs and karst reservoirs were developed. In conclusion, the research results are of guiding significance to the exploration of Maokou Formation oil and gas in the Upper Yangtze region. Moreover, the Maokou Formation in the Sichuan Basin is a new trillion-cubic-meter all-round exploration layer, exhibiting the characteristics of thin reservoirs with strong concealment in the conventional field and the advantages of ultra-high organic matter enrichment in the unconventional field.更多还原