四川盆地中西部中侏罗统沉积相带展布及天然气勘探选区

Distribution of the Middle Jurassic Sedimentary Facies and Gas Exploration Targets in Central and West Sichuan

川西坳陷中侏罗统的千佛崖、沙溪庙组是重要的油气勘探层位。通过沉积特征分析和对比,砂泥百分含量平面变化研究,建立了各亚段的沉积古地理面貌及可能的砂体叠合分布区。结合有利相带特征研究认为,千佛崖组的河床亚相或滨湖滩环境形成的砂、砾岩储集体具有相对较好的物性条件,沙溪庙组的储集砂体主要为辫状河道及三角洲前缘分流河道砂体,其它微相类型砂体较少见,在此基础上预测出了有利地区。

The Middle Jurassic Qianfoya and Shaximiao Formations in the west Sichuan depression are important petroleum reservoirs. The study of sedimentary facies and paleogeographic reconstruction based on analysis and correlation of sedimentary characteristics and change in sand-mud percentage indicate that sandstone and conglomerate reservoir bodies in the fluvial subfacies and coastal lake beach of the Qianfoya Formation are good reservoir rock beds, and reservoir bodies in the Shaximiao Formation consist mainly of sand bodies in braided river course and delta frontal distributary channel. Accordingly, petroleum exploration targets are predicted.