川西南井研—犍为地区筇竹寺组沉积古环境与有机质富集机制  

Sedimentary paleoenvironment and organic matter enrichment mechanism of the Qiongzhusi Formation in Jingyan-Qianwei area,Southwest Sichuan

作　　者：熊亮[1] 董晓霞[1] 魏力民[1] 王同[1] 沈杰 何建华 邓虎成[2,3] 徐浩[2,3] XIONG Liang;DONG Xiaoxia;WEI Limin;WANG Tong;SHEN Jie;HE Jianhua;DENG Hucheng;XU Hao(Exploration and Development Research Institute of Southwest Oil and Gas Branch,SINOPEC,Chengdu 610095,China;College of Energy,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]中国石化西南油气分公司勘探开发研究院,四川成都610095 [2]成都理工大学能源学院,四川成都610059 [3]油气藏地质及开发工程全国重点实验室(成都理工大学),四川成都610059

出　　处：《天然气地球科学》2024年第12期2091-2105,共15页Natural Gas Geoscience

基　　金：国家自然科学基金面上项目(编号:42072182);中国石化西南油气分公司科研项目(编号:KJ-767-2331)联合资助。

摘　　要：川西南井研—犍为地区筇竹寺组页岩气资源丰富,勘探潜力巨大,但其沉积古环境及有机质富集机制尚不明确,严重制约着该地区页岩气勘探开发。为查明井研—犍为地区筇竹寺组古沉积环境演化规律及有机质富集机制,基于主微量元素测试和气相色谱—质谱分析,结合有机地球化学指标、生物标志物、成烃生物组分及岩石矿物组分等对研究区古沉积环境条件及有机质来源等进行综合分析。研究表明,井研—犍为地区筇竹寺组古沉积环境纵向差异明显,海侵期有机碳含量相对较高,有机质来源以浮游绿藻为主,单位生烃潜力较为有限,但相对开阔的水体环境结合温暖潮湿的古气候条件有利于生物的繁殖和生长,具有一定的初级古生产力。在此基础上,有机质富集主要受氧化还原条件控制,并受沉积速率、水体盐度等多因素影响,整体形成以保存条件控制为主的有机质富集模式。此外,研究区筇竹寺组中下部受热液活动影响显著,具有极高的古生产力条件,但其过高的热液活动反而导致了水底还原环境的动荡,有机质流失严重。The Qiongzhusi Formation in Jingyan-Qianwei area of Southwest Sichuan is rich in shale gas resourc⁃es and has great exploration potential,but its sedimentary paleoenvironment and organic matter enrichment mechanism are still unclear,which seriously restricts shale gas exploration and development in this area.In or⁃der to figure out the evolution law of paleoenvironment and the organic matter enrichment mechanism of the Qiongzhusi Formation in Jingyan-Qianwei area,based on major and trace element tests and gas chromatogra⁃phy-mass spectrometry analysis,combined with organic geochemical indicators,biomarker compounds,hydro⁃carbon-forming biological components and rock mineral components,the paleoenvironment conditions and or⁃ganic matter sources in the study area were comprehensively analyzed.The research shows that the paleoenvi⁃ronment of the Qiongzhusi Formation in Jingyan-Qianwei area is obviously different vertically.During the trans⁃gression period,the total organic carbon content is relatively high,and the organic matter comes mainly from phytoplankton,with limited hydrocarbon generation potential per unit.However,the relatively open water envi⁃ronment combined with warm and humid paleoclimatic conditions is conducive to the reproduction and growth of organisms and has certain primary paleoproductivity.On this basis,the enrichment of organic matter is mainly controlled by redox conditions,and influenced by many factors such as depositional rate and water salinity.This shows a model of organic matter enrichment mainly controlled by preservation conditions.In addition,the mid⁃dle and lower parts of the Qiongzhusi Formation in the study area are significantly influenced by hydrothermal activity,which has extremely high paleoproductivity conditions,but its excessive hydrothermal activity has led to the turbulence of the underwater reduction environment and serious loss of organic matter.

关 键 词：有机质富集 沉积环境 生物标志物 热液活动 有机质来源 筇竹寺组 井研—犍为地区 

分 类 号：TE121.1[石油与天然气工程—油气勘探]