Characteristics of “Guangyuan-Wangcang” trough during Late Middle Permian and its petroleum geological significance in northern Sichuan Basin, SW China

作者：Xingzhi Wang, Bo Li, Xiyan Yang, Xiyan Yang, Long Wen, Liang Xu, Shengyang Xie, Yao Du, Mingyou Feng, Xuefei Yang, Xuefei Yang, Yaping Wang, Senqi Pei · 发表于：Petroleum Exploration and Development · 年份：2021 · DOI：10.1016/s1876-3804(21)60052-6 · 被引用次数：32 · 研究领域：Hydrocarbon exploration and reservoir analysis、Geological and Geophysical Studies、Geochemistry and Elemental Analysis

Based on outcrop characteristics, combined with regional tectonic background, drilling and geophysical data, the sedimentary characteristics of the Middle Permian Maokou Formation in the northern Sichuan Basin was studied by means of macroscopic and microscopic observation, geochemical element test, total organic carbon content and vitrinite reflectance measurement. There is a set of deep-water sediments rich in organic matter in the Guangyuan-Wangcang area of northern Sichuan during the late depositional period of the Middle Permian Maokou Formation. The strata are distributed from northwest to southeast, with thickness of 10–30 m, mainly composed of siliceous rocks and siliceous mudstones, intercalated with gravity flow deposits. Siliceous rocks and siliceous mudstones are characterized by thin single layer, flat bedding and rich siliceous radiolarians, calthrop and brachiopod with small body and thin shell, belonging to the typical sedimentary characteristics of deep-water trough facies. The contents of Cu, Co, Mo, Ni and the ratio of Ni to Co in the geochemical tests all indicate that the siliceous rocks are products of deep-water reducing environment. The TOC value ranges from 3.21% to 8.19%, with an average of 5.53%, indicating that the siliceous rocks have good hydrocarbon generation ability. The south side of the trough is in platform margin facies with high energy, and the sediments are mainly thick massive micritic-calcsparite biogenic (clastic) limestone, which is ...