上扬子下寒武统龙王庙组沉积模式与油气勘探方向

Sedimentary Model and Hydrocarbon Exploration Targets of the Lower Cambrian Longwangmiao Formation in the Upper Yangtze Area

在黔东湘西一带,龙王庙组中上部发育大规模、连续分布的浅滩和藻礁以及多种浅水成因的重力流沉积,表明龙王庙组沉积中、晚期上扬子碳酸盐岩台地初具镶边台地沉积模式特征。受古地理和古气候控制,潮坪—泻湖—局限台地相带宽广;龙王庙组沉积中、晚期上扬子海域发生区域性海退,泻湖以及咸化泻湖规模扩大,台地边缘礁滩快速向上增长并向东迁移,斜坡带上发育多种重力流沉积。叠合于加里东期古隆起之上的龙王庙组台内滩,以及巨厚膏盐岩成因的盐构造上下的圈闭都具有良好的油气勘探潜力。

In eastern Hunan and western Guizhou, within the middle and upper parts of the lower Cambrian Long- wangmiao Formation, large-scale, continuous distribution of shoal and reef facies deposits were developed in the platform margin, as adjacent to shallow water gravity flow deposits developed on the shelf slope, indicating preliminary characteristics of a rimmed platform deposition. Controlled by the paleo-geography and paleo-climate in this period, tidal flat-lagoon-restricted platform facies is broad. Regional regression in the middle and late Longwangmiao period saw the lagoon scale expanded, and the bank and reef of the platform margin quickly grew and migra- ted to the east,and gravity flow deposits were developed in the slope belts. The inside bar of Longwangmiao Formation which is superimposed on the Caledonian paleo-uplift, as well as the hydrocarbon traps above or under the salt structures, have good hydrocarbon exploration potential.