【作者】 张成；

【导师】 解习农；

【作者基本信息】 中国地质大学 ， 能源地质工程， 2006， 博士

【摘要】 古近纪以来，渤中坳陷持续强烈的构造运动造就了该地区多生烃凹陷、多套烃源岩、多套成藏组合的复杂背景。如何揭示这种复杂背景下的油气成藏动力学及其主要控制因素必然成为影响渤中地区油气勘探能否取得更大进展的关键。而输导体系和油气成藏模式研究是成藏动力学研究的前提和基础。本选题在国家自然科学重点基金资助下，密切追踪学科前沿和热点，从渤中坳陷区域背景分析入手，以典型含油气构造为着力点，在不同尺度范围上研究油气运移输导通道及其流体行为，进而总结油气成藏模式。主要认识如下： 1．阐明了渤中地区主力烃源岩的环境背景与地化特征以及油源对比的复杂性。 渤中地区主要发育沙河街组三段、沙河街组一段和东营组下段等三套成熟烃源岩。沉积环境和气候条件决定了不同烃源岩的有机质丰度和类型存在明显差异。比较而言，沙河街组三段烃源岩不仅分布范围广、沉积厚度大；而且ⅡA型和ⅡB型有机质均占相当比例，因而是渤中地区质量最好的烃源岩。三套烃源岩具有不同的生物标志物组成，应用伽马蜡烷指数和4-甲基甾烷／∑C₂₉甾烷等生物标志物指标可以有效地将它们区分开来。原油类型多样、地球化学特征复杂，尤其是新近系原油遭受了严重的生物降解，各种地球化学指标均发生了变化；而且已知油藏基本处于凹陷之间的凸起上，存在不同凹陷多套烃源岩同时供烃的“地利”条件。因而对不同层位、不同构造单元原油的来源，应具体问题具体分析。 2．分析了渤中地区的地层温度场特征及其演化规律。 实测温度资料表明，渤中地区现今地层温度与深度总体具有较好的相关性，但不同区域、不同层位的地温梯度存在较大差异。凸起带地温梯度明显高于凹陷地温梯度，可能与凹陷内较低的岩石热导率和凸起带周缘沿深大断裂显著的热流体活动有关。古温标分析表明，渤中地区古地温梯度和古热流值均高于现今时刻，较高的古地温梯度和古大地热流值不仅揭示裂后期（25Ma～现今）以来的持续冷却，同时也揭示裂陷期（50～25Ma）内可能已达到较高的有机质成熟度和存在比较活跃的流体活动。 3．总结了渤中地区压力场特征，划分常压和超压2套压力系统，并探讨了超压成因。 实测压力资料表明，渤中地区深层存在明显的超压现象，超压系统顶面埋深大致在3000～3500m左右，总体表现为自凸起带向凹陷内逐渐增大的趋势。声波压实曲线资料表明，渤中地区深层存在明显的欠压实现象，欠压实带顶面埋深与超压系统顶面埋深基本一致，根据欠压实带特征可将超压系统分为东营组和沙河街组两个次级超压系统，但其分界面与地层界面并不完全吻合。渐新世以来快速沉降引起的欠压实以及生烃和原油裂解作用共同决定渤中地区发育了渤海湾盆地最强的超压；水热增压和粘土矿物脱水作用对超压形成可能也有一定贡献。更多还原

【Abstract】 Since Paleogene, strong tectonic movement resulted in the formation of multiple hydrocarbon-generating depressions, multiple hydrocarbon source rocks and multiple hydrocarbon accumulation assemblages in the Bozhong depression. This kind of complex geological condition determines that study on hydrocarbon accumulation dynamics becomes the key factor influencing hydrocarbon exploration effect. Study on hydrocarbon migration pathway and hydrocarbon accumulation model are the base of hydrocarbon accumulation dynamics. Supported by the National Key Natural Science Foundation of China and guiding with advanced theories and methods, this study analyzed hydrocarbon migration pathways and fluid flow and summarized hydrocarbon accumulation models in the different scale based on the research of regional geological background and typical petroliferous structure. The main results in this dissertation are as follows:1. Analysis on organic geochemistry of the Bozhong depression indicate that there are three sets of mature hydrocarbon source rocks including mudstones in the 3rd member of the Shahejie Formation, the 1st member of the Shahejie Formation and the lower member of the Dongying Formation, respectively. Sedimentary environment and climate determine that abundances and types of organic matters in various hydrocarbon source rocks are different. Compared with other two sets of hydrocarbon source rocks, those in the 3rd member of the Shahejie Formation not only have broader distribution and larger depositional thickness, but also have plentiful II A-type and II B-type kerogen, so are the best of the three sets of mature hydrocarbon source rocks. Compositions of biomarkers are different in various hydrocarbon source rocks. They can be effectively distinguished according to values of their gammacerane/C₃₀aβ-sterane and 4-methylsterane/C29 regular sterane. Crude oil displays multiple types and complex geochemical characteristics, especial. Especially, crude oil in Neogene has suffered serious biodegradation, and many kinds of geochemical parameters have largely changed. Moreover, Moreover, known oil reservoirs are situated at uplifts among these depressions, benefit from multiple sets source rocks in different depressions. Therefore, we should analyze concretely for various problems.2. Measured formation temperature data show that Present formation temperature has a更多还原