强改造区牛蹄塘组页岩气保存条件指数评价

中上扬子区下寒武统牛蹄塘组是我国页岩气最具勘探潜力的目的层位之一。恩施-利川地区的牛蹄塘组是页岩气主要富集区，该地区经历了多期次多旋回构造叠加作用，研究区内下古生界海相页岩受构造变形、断裂、剥蚀等强烈改造作用影响引起区域性能量场变化，致使页岩气吸附/解吸、渗流/扩散等成藏条件发生变化，从而导致研究区内下古生界页岩气保存产生重大调整。以恩施-利川地区下古生界下寒武统牛蹄塘组页岩层系为研究对象，从物质基础、构造作用和演化历史等几个方面对页岩气保存条件进行研究，并综合分析各项指数，提出页岩气保存条件综合评价指数体系，以期对研究区勘探提供进一步的参考资料。

Evaluation Index of Shale Gas Preservation for Niutitang Formation in the Strong Transformation Zone

Niutitang Formation is one of the most potential strata for exploration in the Upper Yangtze platform.Enshi-Lichuan is located within the shale gas abundant play of Niutitang Formation in the Upper Yangtze platform.This area has experienced cycles and stages of structural overlap and rework.The marine shale in the Lower Paleozoic has experienced changes of regional energy field by different rework of structural deformation,faults,uplift,erosion.Fluid flow and diffusion cause the adjustment of the preservation of shale gas,resulting in the changes of shale gas accumulation conditions of adsorption and desorption.This paper studied the shale gas preservation conditions by material basis,tectonism and evolutionary history of Niutitang in the Lower Cambrian of the Lower Paleozoic in Enshi-Lichuan.The evaluation system of shale gas preservation of South China was put forward by comprehensive analysis of various parameters.