引用本文：熊小辉,王剑,熊国庆,汪正江,门玉澎,周小琳,周业鑫,杨潇,邓奇.2018.渝东北地区五峰组—龙马溪组页岩气地质特征及其勘探方向探讨[J].地质学报,92(9):1948-1958. XIONG Xiaohui,WANG Jian,XIONG Guoqing,WANG Zhengjiang,MEN Yupeng,ZHOU Xiaolin,ZHOU Yexing,YANG Xiao,DENG Qi.2018.Shale Gas Geological Characteristics of Wufeng and Longmaxi Formations in Northeast Chongqing and Its Exploration Direction[J].Acta Geologica Sinica,92(9):1948-1958.
Abstract:Dark mudstone and shales of Wufeng Formation-Longmaxi Formation in Northeast Chongqing have a thickness ranging from 30.92m to 164.47m, with the thickest layers mainly in the Xianchi section of Chaoyang Town and Tianba section of Tianba Town. Thickness also decreases toward west and the east respectively. The average total organic carbon (TOC) content in the study area is 3.32%, among which the middle area has an average TOC content of 3.93% and the west region has an average TOC content of 3.59%. Compared with 2.77% in the east, the west and east of the study area have much high TOC abundance. The dark mudstone and shales are characterized by type I organic mater, with minor type Ⅱ-Ⅱ2 kerogen distributing in the western and eastern regions. Organic matter in the study area shows generally high or even over maturity, with maturity gradually increasing from north to south. Higher contents of quartz and brittle minerals especially in the middle-western areas and lower clay mineral are better to produce gas-storage cracking and hydrofracturing. In terms of property of reservoirs, the dark mudstone and shales in the middle region are dominated by organic matter porosity with high porosity and lower permeability as well as high surface area. Gas field in the central area from Tianba, Chaoyang to Wenfeng are of better gas bearing capability. Combined the total thickness of shales, distribution of total organic carbon, and preservation conditions of reservoirs and structures, it can be concluded that the northeastern part of Chongqiang is of favorable prospecting outlook for shale gas and should be the target area for future exploration.