Fine-grained sedimentary characteristics and influencing factors of the Lower Cambrian Qiongzhusi Formation in Sichuan Basin and on its periphery

The Lower Cambrian Qiongzhusi Formation in Sichuan Basin and on its periphery is rich in shale gas resources, and it has become one of the important shale gas development intervals in Sichuan Basin. Controlled by complex sedimentary setting, the silty shale reservoir in Qiongzhusi Formation has various lithofacies and strong heterogeneity longitudinally, which restricts the exploration and development of shale gas. Therefore, it is urgent to study the sedimentary characteristics, sedimentary facies and sedimentary models. Based on the previous understanding of tectonic setting and sequence stratigraphy, and through detailed analysis of rock data, well logging data, geochemistry data and paleontology data, this paper clarifies the Early Cambrian sedimentary background of combined ocean-paleoland influence, moderate water depth and widespread reduction of Sichuan Basin and its periphery. The paper also believes that the Qiongzhusi Formation is mainly deposited in shore facies and continental shelf facies. The c