川中地区中二叠统海相烃源岩特征及生烃潜力评价  

Characteristics and hydrocarbon generation potential of Middle Permian marine source-rocks in central Sichuan Basin

作　　者：王伟[1] 任丽梅[2] 梁家驹[1] 唐松[2] 袁海锋[1] 李昱翰 Wei WANG;Limei REN;Jiaju LIANG;Song TANG;Haifeng YUAN;Yuhan LI(State Key Laboratory of Oil&Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;Central Sichuan Division,PetroChina Southwest Oil&Gasfield Company,Suining 629000,China)

机构地区：[1]成都理工大学,油气藏地质及开发工程国家重点实验室,四川成都610059 [2]中国石油西南油气田公司川中油气矿,四川遂宁629000

出　　处：《天然气地球科学》2022年第3期369-380,共12页Natural Gas Geoscience

基　　金：中国石油西南油气田分公司课题“川中磨溪—龙女寺地区栖霞组天然气富集规律研究”(编号:20200301-12);四川省科技厅项目“四川盆地三叠系杂卤石型钾盐形成条件与成因机制研究”(编号:2020YJ0426)联合资助。

摘　　要：近几年,随着角探1井、南充1井、潼探1井、高石18井、磨溪42井等在中二叠统茅口组和栖霞组勘探获得高产工业气流,使得川中地区中二叠统成为了天然气勘探的热门层系。研究表明:川中地区中二叠统天然气的供烃层系主要为下古生界和中二叠统自身的烃源岩,天然气大多表现为混源气的特征。当前对于四川盆地下古生界海相烃源岩的研究程度较高,但对于中二叠统海相烃源岩的研究程度较低,因此明确中二叠统海相烃源岩的展布及生烃潜力成了当下亟待解决的问题。为了精细刻画川中地区中二叠统海相碳酸盐岩烃源岩的特征及生烃潜力,分别从烃源岩地球化学特征、烃源岩测井响应特征、以及烃源岩展布特征进行详细描述,在此基础上对川中地区中二叠统海相烃源岩的生烃潜力进行了系统评价。结果表明:(1)川中地区中二叠统海相烃源岩主要为差—中等品质烃源岩,茅口组烃源岩品质要优于栖霞组;烃源岩有机质类型主要为Ⅱ_(1)型,其次为Ⅱ_(2)型,均处于过成熟阶段;(2)川中地区中二叠统沉积时为具有一定盐度的还原性沉积水体环境;(3)烃源岩总有机碳(TOC)测井响应特征明确,TOC含量与自然伽马(GR)和声波时差(AC)相关性最好,可以据此针对川中地区中二叠统开展TOC预测;(4)纵向上,烃源岩主要发育在栖霞组中下部(栖一段)和茅口组中下部(茅一段—茅二c亚段);横向上,呈现出向北东方向逐渐增厚的特征;(5)川中地区茅口组生烃强度优于栖霞组,主要介于(10~50)×10^(8)m^(3)/km^(2)之间,由南西向北东方向逐渐增高,茅口组总生烃量为57.38×10^(12)m^(3)。In recent years,the Middle Permian in central Sichuan Basin has become a popular reservoir for natural gas exploration,with the high-yield industrial gas flow obtained from the exploration of Wells JT1,NC1,TT1,GS18 and MX42 in the Maokou and Qixia formations of the Middle Permian.The research shows that the hydrocarbon supply strata of Middle Permian natural gas in central Sichuan Basin are mainly the source rocks of Lower Paleozoic and Middle Permian,and the natural gas is mostly mixed source gas.At present,the research degree of Lower Paleozoic marine source rocks in Sichuan Basin is relatively high,but the research degree of Middle Permian marine source rocks is relatively low.Therefore,it is urgent problem to determine the distribution and hydrocarbon generation potential of middle Permian Marine source rocks.In order to describe the characteristics and hydrocarbon generation potential of the Middle Permian marine carbonate source rocks in central Sichuan Basin,this paper describes in detail the geochemical characteristics,logging response characteristics and distribution characteristics of the source rocks,and systematically evaluates the hydrocarbon generation intensity of the Middle Permian marine source rocks in central Sichuan Basin.The results show that:(1)The marine source rocks of the Middle Permian in central Sichuan are mainly poor to medium quality source rocks,and the quality of the source rocks of Maokou Formation is better than that of Qixia Formation;the organic matter types of source rocks are mainly typeⅡ_(1),followed by typeⅡ_(2),which are in the over-mature stage;(2)The middle Permian in the central Sichuan basin was a reductive sedimentary environment with certain salinity;(3)The logging response characteristics of organic carbon(TOC)in source rocks are clear,and the organic carbon(TOC)has the best correlation with natural gamma(GR)and acoustic time difference(AC),so the TOC content of organic carbon can be predicted for the Middle Permian in central Sichuan Basin;(4)Vertically,the sou

关 键 词：四川盆地 川中地区 中二叠统 海相烃源岩 生烃潜力 

分 类 号：P618.13[天文地球—矿床学]