四川盆地中二叠统茅口组储层形成与古构造演化关系

摘要

以钻井与测井资料、盆地基干地震剖面及区域地质资料为基础，开展了四川盆地中二叠统茅口组储层发育特征及主控因素分析，系统讨论了古构造演化与茅口组沉积地貌、岩溶地貌及白云石化带之间的关系，预测了储层发育有利区带。研究认为，加里东运动奠定了中、下二叠统沉积前的基本地貌格局，而峨嵋地幔柱隆升作用则持续影响了整个二叠纪的古地貌演化，使四川盆地西南部成为继承性古地貌高带。该区既是茅口组高能滩体发育的沉积地貌高带，也是茅口组顶部风化壳岩溶古地貌高地。峨眉地裂运动的构造张裂活动，为茅口组在早期滩体沉积或岩溶改造的基础上，叠加多期次白云石化及溶蚀作用提供了热液及酸性成岩流体的运移通道，在很大程度上控制了盆内茅口组白云岩储层的分布。%The development characteristics and main controlling factors of reservoirs in the Middle Permian Maokou For-mation in Sichuan Basin were studied based on drilling and logging data ,framework seismic sections and regional geolo-gical data.The relationship between paleostructure evolution and formation of geomorphology ,karst landform and dolomiti-zation zone of the Formation ,was also discussed systematically to predict potential reservoir zones there .Study shows that the Caledonian Movement defined and shaped the fundamental landforms of the Middle & Lower Permian in the Basin and the Emei mantle plume ’ s uprising exerted a continuous influence on the paleogeomorphology evolution in the whole Permian.As a result,southwestern Basin turned to an inherited paleogeomorphological high .It is not only a sedimentary paleogeomorphological high for the development of high energy bank depositsin the Formation but also a paleogeomorpho -logical high for the development of weathering crust karst on top of the Formation .Emei tafrogeny provided migration pathways of hydrothermal fluid and acid diagenesis fluids for the overprint of multi -stage dolomitization and dissolution on early band deposits and karstification ,thus largely controlled the distribution of dolomite reservoirs in the Formation .