川东南上二叠统龙潭组泥页岩发育特征

为了探讨四川盆地东南部二叠统龙潭组泥页岩的资源潜力,在总结近年来四川盆地东南部龙潭组研究现状的基础上,根据野外露头、岩心和测井等资料,以层序地层与沉积相理论为基础,建立了层序界面识别标志和层序地层格架,研究了沉积相对岩性分布的影响,总结了龙潭组泥页岩岩性组合特征和泥页岩厚度特征。研究结果表明,四川盆地东南部龙潭组由底至顶依次划分为SQ1、SQ2、SQ3三级层序,SQ1层序由低位体系域、海侵体系域和高位体系域构成,而SQ2层序和SQ3层序则皆由海侵体系域和高位体系域构成;四川盆地东南部泥页岩组合及厚度受控于沉积环境:滨岸相主要泥页岩组合为泥包砂,厚度大;潮坪相主要泥页岩组合为泥包砂,有效厚度仅次于滨岸相;混积陆棚相泥页岩组合以泥包灰为主,较薄; SQ1段、SQ2段和SQ3段泥页岩厚度总体上表现为西南部厚、东北部薄的变化趋势。

Characteristics of shale development of the upper two Permian Longtan Formation in southeastern Sichuan Basin,China

The Longtan Formation shale developed in the upper two Permian of Sichuan basin is widely distributed, and has potential to become the next main gas producing horizon of shale gas. On the basis of summarizing the research status of Longtan Formation in the east of Sichuan Province in recent years, through field profile research, logging data interpretation and indoor microscopic thin slices, combined with the development characteristics of mud shale in the Longtan Formation in the study area, the influence of the sediment shale thickness characteristics and shale combination characteristics is studied. The results show that the shale assemblage and thickness are controlled by sedimentary environments in southeastern Sichuan. The main shale assemblage of littoral facies is mud-encased sand, the thickest. The main shale assemblage of tidal flat facies is mud pack sand, and the effective thickness is only inferior to the shore facies. The shale assemblage of mixed continental shelf facies is mainly covered by mud and ash. There is no shale assemblage in the basin facies. It has a certain significance to further discuss the influence of sedimentary environment on the development characteristics of shale.