渤中凹陷古近系优质烃源岩特征及分布  

Characteristics and distribution of Paleogene high-quality source rocks in Bozhong sag

作　　者：任拥军[1] 杜雨佳 郭潇潇 王冠民[1] 

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]中海石油(中国)有限公司湛江分公司,广东湛江524057

出　　处：《油气地质与采收率》2015年第1期5-13,共9页Petroleum Geology and Recovery Efficiency

基　　金：国家科技重大专项"渤海海域已证实的富生烃凹陷再评价及新领域勘探方向"之"渤中凹陷油气成藏规律及勘探方向研究"(2011ZX05023-001-013)

摘　　要：综合应用钻井、地震等地质资料,以大量烃源岩样品地球化学分析为基础,从有机质丰度、类型、成熟度、沉积环境、母质来源以及生物标志物等方面对渤中凹陷古近系烃源岩地球化学特征进行了研究,指出了渤中凹陷优质烃源岩的发育层段,阐明了优质烃源岩的形成条件和分布规律,并在此基础上剖析优质烃源岩与油气成藏的关系,进一步揭示了渤中凹陷的勘探潜力。研究结果表明,渤中凹陷沙三段、沙二段—沙一段以及东营组3套烃源岩中都存在有机质丰度高、类型好、生排烃潜力大的优质烃源岩。其中,沙三段烃源岩有机质类型以Ⅰ型和Ⅱ1型为主,有机质丰度最高且已经进入生烃门限,优质烃源岩最为发育。从母质来源和沉积环境方面分析了3套烃源岩的形成条件,发现生物产率高、母源类型好、保存条件良好是优质烃源岩形成的主要原因。总结了优质烃源岩的时空展布特征,优质烃源岩的形成受控于沉积环境和沉积中心,主要发育于半深湖—深湖相带,由沉积中心向外逐渐变薄;优质烃源岩的空间分布控制了渤中凹陷油气分布,凹陷近源斜坡带是进一步油气勘探的有利地区。Based on the drill and seismic data and the organic geochemical analysis data of the source rocks,the geochemical characteristics of Paleogene source rocks in Bozhong sag have been studied from several aspects such as organic abundance and types,maturity,sedimentary environment,original source of rock and biological markers,etc. The area,where the high-quality source rocks developed,has been pointed out. And then the forming conditions and distribution of the high-quality source rocks have been described. On this basis,all the relationships between high-quality source rocks and hydrocarbon reservoirs have been analyzed to reveal the exploration potential in Bozhong sag. The studied results show that there are three sets of hydrocarbon source rocks developing respectively in the third member of Shahejie Formation,the second member and the first member of Shahejie Formation,and Dongying Formation. The source rocks have high quality,good types and great potential for hydrocarbon generation and expulsion. The types of source rocks in the third member of Shahejie Formation are mainlyⅠandⅡ1,and the rocks have the highest abundance of organic matter and are in the threshold of hydrocarbon generation with the highest quality. It is found that the main conditions for high-quality rocks generation are high rate of biological generation,good source material and good preservation conditions through analyzing forming conditions of the three sets of hydrocarbon source rocks from the aspects of source material and sedimentary environment. Then the spatial and temporal distribution characteristics were summarized. The high-quality source rocks generation is controlled by sedimentary environment and centre,where semi-deep lake or deep lake developed and the source rocks becamethinner from centre to outsides. In Bozhong sag,the distribution of high-quality source rocks controls oil and gas distribution and the slope areas near the depression center are the favorable exploration targets.

关 键 词：优质烃源岩 地球化学特征 形成条件 空间分布 渤中凹陷 

分 类 号：TE112.113[石油与天然气工程—油气勘探]