中国海相盆地深层白云岩储层特征及成因机理  

Characteristics and genesis mechanisms of deep dolomite reservoirs in China's marine basins

作　　者：李茜 朱光有 李婷婷[1] 陈玮岩 艾依飞 张岩 段鹏珍 刘金城 LI Xi;ZHU Guangyou;LI Tingting;CHEN Weiyan;AI Yifei;ZHANG Yan;DUAN Pengzhen;LIU Jincheng(Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China;School of Geosciences,Yangtze University,Wuhan,Hubei 430100,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]长江大学地球科学学院,湖北武汉430100

出　　处：《世界石油工业》2024年第4期35-47,共13页World Petroleum Industry

基　　金：中国石油天然气股份有限公司科学研究与技术开发项目“海相碳酸盐岩成藏理论与勘探技术研究”(2021DJ05)。

摘　　要：基于中国特殊的叠合型海相盆地背景,深层白云岩在埋藏过程中遭受了多期流体叠加改造,造成富镁流体的迁移机制与白云石化过程难以被有效示踪,制约了油气勘探决策。Mg同位素是白云石化流体的直接示踪剂,在探究深层白云岩成因方面已取得初步成效。为推动Mg同位素在深层白云岩成因方面的应用与深层白云岩油气突破进程,系统介绍了中国海相盆地深层白云岩分布与油气勘探现状,Mg同位素实验技术流程、数据有效性评估和示踪原理,以及不同类型深层白云岩的Mg同位素特征和成因机制。结论表明:(1)中国海相盆地深层白云岩具有发育时代跨度长、分布范围广、储层类型多样、油气资源丰富等特征,是当前和未来油气勘探开发的重点领域;(2)微生物白云岩主要发育于前寒武纪地层,其Mg同位素相对偏低,白云岩的形成受微生物繁盛程度和海洋化学性质控制;(3)准同生白云岩是中国发育最广泛的白云岩储层类型,其Mg同位素与海平面周期性波动相互耦合,指示白云石化过程的流体来源于海水,白云岩的厚度与分布受相对海平面变迁的控制;(4)埋藏或热液白云岩的富镁流体来源较为复杂,其Mg同位素在垂向上往往呈无规律波动状态,白云岩的分布主要受温度、压力及断层控制。为揭示中国海相盆地深层白云岩储层成因机理提供了新的技术手段,对指导深层白云岩储层大模规油气勘探具有深远意义。Based on the special superimposed marine basin background in China,deep dolomite has been subjected to multi-stage fluid superposition and transformation during burial,which makes it difficult to effectively trace the migration mechanism of magnesium-rich fluid and dolomitization process,and restricts oil and gas exploration decision-making.Mg isotope is a direct tracer of dolomite fluid,and has achieved initial results in exploring the genesis of deep dolomite.To further promote the application of Mg isotope in the genesis of deep dolomite and the breakthrough process of deep dolomite reservoirs oil and gas exploration,this paper systematically introduces the distribution and oil and gas exploration status of deep dolomite in marine basins in China,the technical process of Mg isotope experiment,data validity evaluation and tracer principle,as well as the Mg isotope characteristics and genetic mechanism of different types of deep dolomite.The following conclusions are drawn:(1)Deep dolomite in marine basins in China has the characteristics of long development age span,wide distribution range,diverse reservoir types and rich oil and gas resources,which is the key area of oil and gas exploration and development at present and in the future.(2)Microbial dolomite is mainly developed in the Precambrian strata,and its Mg isotope is relatively low.The formation of dolomite is controlled by the degree of microbial prosperity and marine chemical properties.(3)The penecontemporaneous dolomite is the most widely developed dolomite reservoir type in China.Its Mg isotope is coupled with the periodic fluctuation of sea level,indicating that the fluid in the dolomitization process is derived from seawater,and the thickness and distribution of dolomite are controlled by relative sea level changes.(4)The sources of Mg-rich fluids in buried or hydrothermal dolomites are complex,and their Mg isotopes often exhibit irregular fluctuations in the vertical direction.The distribution of dolomites is mainly controlled by temperature,pres

关 键 词：海相盆地 油气勘探 深层白云岩 MG同位素 流体迁移 白云石化 

分 类 号：TE12[石油与天然气工程—油气勘探]