泥页岩沉积特征与生烃能力——以东营凹陷沙河街组三段中亚段—沙河街组四段上亚段为例

发布时间：2018-05-15 04:21

本文选题：泥页岩 + 沉积特征　；参考：《石油学报》2017年01期

【摘要】：泥页岩的沉积环境与形成方式都将控制其矿物、有机质特征并影响岩石的生烃潜力。选取东营凹陷古近系沙河街组泥页岩,开展岩石薄片观察、X射线衍射和热解等检测,研究岩石的矿物学特征和有机质特征,解析各类泥页岩成因与生烃能力的差异。研究发现,研究区的块状、纹层状和含石膏构造泥页岩中构造特征各异,矿物成分(碎屑、黏土、碳酸盐矿物和石膏类矿物等)含量变化大,有机质特征也各不相同。综合分析矿物与有机质的特征及组合关系,发现细纹层页岩和断续纹层页岩是以生物作用为主导形成的沉积产物,生烃能力最强;宽纹层页岩和均匀块状泥岩属化学沉积作用的产物,具有较强的生烃能力;含碎屑块状泥岩主要通过机械作用沉积而成,含石膏构造泥岩则在蒸发环境下通过化学沉淀形成,两者的生烃能力较弱。比较东营凹陷沙河街组三段中亚段—沙河街组四段上亚段的泥页岩类型,发现沙河街组三段中亚段和沙河街组四段纯下次亚段以机械和化学作用形成的含碎屑块状和含石膏构造泥岩为主,导致2个层段的生烃能力较弱;沙河街组三段下亚段和沙河街组四段纯上次亚段以生物或化学沉积作用形成的纹层状页岩为主,导致2个层段的生烃能力较强。因此,关注泥页岩矿物和有机质组合关系,从机械、化学和生物等沉积方式差异的角度探讨各类泥页岩的成因和生烃能力的变化,能够为非常规油气勘探提供新的思路。
[Abstract]:The sedimentary environment and formation mode of shale will control the characteristics of minerals and organic matter and affect the hydrocarbon generation potential of rocks. The shale of the Shahejie formation of Paleogene in Dongying sag was selected to study the mineralogical characteristics and organic matter characteristics of the rocks by means of X-ray diffraction and pyrolysis of the thin sections of the rocks, and to analyze the difference between the genesis and hydrocarbon generation ability of various shale rocks. It is found that the tectonic characteristics of block, lamellar and gypsum bearing structural shale are different, the contents of mineral components (clastic, clay, carbonate minerals and gypsum minerals, etc.) vary greatly, and the characteristics of organic matter are different. By comprehensive analysis of the characteristics and assemblages of minerals and organic matter, it is found that fine grain shale and intermittent striated shale are sedimentary products dominated by biological action, and the hydrocarbon generation ability is the strongest. Wide-grained shale and homogeneous block mudstone are the product of chemical deposition, and have strong hydrocarbon generation ability, while clastic block mudstone is mainly deposited by mechanical action, while gypsum tectonic mudstone is formed by chemical precipitation in evaporative environment. The hydrocarbon generation ability of both is weak. To compare the shale types of the middle part of the third member of the Shahejie formation and the upper submember of the fourth member of the Shahejie formation in Dongying Sag, It is found that the third member of the Shahejie formation and the fourth member of the Shahejie formation are dominated by clastic block and gypsum tectonic mudstone, which leads to the weak hydrocarbon generation ability of the two formations. The lower submember of the third member of Shahejie formation and the fourth member of the Shahejie formation are dominated by stratified shale formed by biological or chemical deposition, resulting in strong hydrocarbon generation ability of the two formations. Therefore, paying attention to the relationship between shale minerals and organic matter, and discussing the origin and hydrocarbon generation ability of shale from the point of view of mechanical, chemical and biological sedimentary patterns, can provide a new way of thinking for unconventional oil and gas exploration.
【作者单位】：同济大学海洋地质国家重点实验室;中海石油(中国)有限公司上海分公司;中国石油化工股份有限公司胜利油田分公司勘探开发研究院;
【基金】：国家自然科学基金项目(No.41372130,No.41672115) 国家重大科技专项(2016ZX05006-001-003)资助
【分类号】：P618.13

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