摘要
玛湖凹陷玛中构造带深层—超深层的油气勘探逐步成为了准噶尔盆地的热点领域。基于岩心的有机地球化学分析数据和高温热模拟实验,系统剖析了玛湖凹陷玛中构造带二叠系风城组烃源岩的有机质丰度(TOC)、生烃潜量(S_(1)+S_(2))、氢指数(HI)等指标,估算了烃源岩生烃转化率与生气潜力。研究结果表明:①玛中构造带二叠系风城组烃源岩TOC平均值为1.2%,S_(1)+S_(2)平均值为5.6 mg/g,氢指数HI平均值为380 mg/g,有机质生烃转化率高达90%,以生油为主,累计产油率为829 mg/g,高—过成熟阶段累计产气率为40 mL/g,生气量较低,仅占总生烃量的4.3%。②玛湖与玛北背斜构造定型期早于风城组烃源岩的主生排烃期,储层物性差,油气充注强度弱。③玛湖背斜烃源岩埋深普遍大于6000 m(Ro大于1.6%),生烃基本停滞,且缺乏原油裂解成气的温压条件,气源供给不足,不具备形成规模气藏的物质基础;玛北背斜埋藏相对较浅,周缘烃源岩处于成熟—高成熟阶段(Ro为1.0%~1.5%),具备形成致密轻质油藏的潜力。
The deep to ultra-deep oil and gas exploration of Mazhong structural belt in Mahu Sag has gradually become a hot field in Junggar Basin.Based on organic geochemical analysis data of rock cores and hightemperature thermal simulation experiments,the organic matter abundance(TOC),hydrocarbon generation potential(S_(1)+S_(2)),hydrogen index(HI)of Permian Fengcheng Formation source rocks in Mazhong structural belt of Mahu Sag were systematically analyzed,and the hydrocarbon conversion rate and gas generation potential of the source rocks were estimated.The results show that:(1)The average TOC of Permian Fengcheng Formation source rocks in Mazhong structural belt is 1.2%,the average hydrocarbon generation potential(S_(1)+S_(2))is 5.6 mg/g,and the average hydrogen index(HI)is 380 mg/g.The hydrocarbon conversion rate of organic matter is high upto 90%,mainly for oil generation,with a cumulative oil production rate of 829 mg/g.The cumulative gas production rate during the high-mature to over-mature stage is 40 mL/g,and the gas production is relatively low,accounting for only 4.3%of the total hydrocarbon generation.(2)The structural formation period of Mahu and Mabei anticlines is earlier than the main hydrocarbon generation and expulsion period of Fengcheng Formation source rocks,and the reservoir properties were poor,with weak intensity of oil and gas charging.(3)The burial depth of source rocks in Mahu anticline is generally greater than 6000 m(Ro greater than 1.6%),and hydrocarbon generation has basically stagnated.Moreover,a lack of temperature and pressure conditions for crude oil cracking into gas results in insufficient gas supply and a lack of material basis for forming large-scale gas reservoirs.The burial depth of Mabei anticline is relatively shallow,and the surrounding source rocks are in the mature to high mature stage(Ro being 1.0%-1.5%),which has the potential to form tight light oil reservoirs.
作者
刘冠伯
陈世加
李世宏
邹阳
李勇
LIU Guanbo;CHEN Shijia;LI Shihong;ZOU Yang;LI Yong(School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China;Exploration and Development Research Institute,Xinjiang Oilfield Company,Karamay 834000,Xinjiang,China)
出处
《岩性油气藏》
北大核心
2025年第5期83-96,共14页
Lithologic Reservoirs
基金
四川省自然科学基金项目“源储间的薄层泥岩对致密砂岩储层含油性的控制机理研究”(编号:2025ZNSFSC0309)
中国石油天然气股份有限公司重大科技专项“页岩油富集规律、资源潜力与有利区带目标评价研究”(编号:2022DJ0108)联合资助。
关键词
烃源岩
生烃转化率
生气潜力
风城组
二叠系
玛湖背斜
玛中构造带
准噶尔盆地
source rock
hydrocarbon generation conversion rate
gas generation potential
Fengcheng Formation
Permian
Mahu anticline
Mazhong structural belt
Junggar Basin
