东营凹陷古近系沙四上亚段细粒岩沉积环境研究
发布时间：2018-10-18 07:44
【摘要】：细粒岩的沉积环境研究对于页岩油的有利区带的预测以及勘探开发具有重要的参考价值。本文以有机质含量丰富的东营凹陷沙四上亚段细粒岩为研究对象,通过对其岩石学特征、纹层特征、整体宏观的沉积环境、岩相组合的控制因素进行分析,对细粒岩的沉积模式以及沉积体系进行提炼分类。在研究过程中,本文创新性地将米兰科维奇旋回同细粒岩进行综合分析,发现天文旋回对于细粒岩的沉积确实有着较大影响作用。其中,尤其以23ka(千年)的岁差旋回的作用最为明显。细粒岩的物质及其来源是细粒岩研究所要解决的基本问题。本文研究区的细粒岩的主要物质组成为石英、碳酸盐、粘土矿物、有机碳以及黄铁矿。石英和粘土矿物以来自陆源为主,还有少量石英是成岩过程中形成的自生石英;碳酸盐以生物化学成因为主,亦有少部分来自陆源;有机质多为Ⅰ型和Ⅱ1型,来自藻类和浮游生物;黄铁矿多为草莓状集合体,高度自形。细粒岩的沉积构造多为水平层理、交错层理、块状层理以及透镜状层理等。研究区细粒岩在薄片下多以纹层形式出现,其基本纹层为粘土纹层、碳酸盐纹层、有机质纹层以及混合纹层。本文针对细粒岩的纹层特征提出了浑水-半浑水-清水模式的纹层成因机制,在浑水阶段多形成粘土纹层或者混合纹层,半浑水阶段多形成混合纹层,清水阶段多形成碳酸盐纹层,由于这个三个阶段持续时间的长短不同,从而导致研究区出现不同的纹层组合。利用研究区重点井自然伽马测井数据进行分析后发现,细粒岩中存在显著的米兰科维奇旋回,其中,23ka的岁差旋回与细粒岩的矿物成分变化具有良好的对应关系,即天文旋回控制了细粒岩的沉积,导致其出现了不同的岩相组合。针对东营凹陷沙四上亚段细粒岩,将其划分为4个沉积体系:1)浑水沉积体系,主要为高有机质泥岩和中有机质泥岩;2)半浑水沉积体系,主要为中有机质混合细粒岩和低有机质混合细粒岩;3)清水沉积体系,主要为中有机质碳酸盐岩和低有机质碳酸盐岩;4)浊流沉积体系,主要为条带状粉砂岩。
[Abstract]:The study of sedimentary environment of fine-grained rocks has important reference value for prediction of favorable zones of shale oil and exploration and development. In this paper, the fine granulites of the upper member of Sha 4 in Dongying sag with abundant organic matter are taken as the research object. The petrological characteristics, the characteristics of the grain layer, the overall macro sedimentary environment and the controlling factors of the lithofacies combination are analyzed. The sedimentary model and sedimentary system of fine-grained rocks are refined and classified. In the course of the research, the Milankovich cycle and the fine-grained rock are analyzed synthetically in this paper. It is found that the astronomical cycle does have a great influence on the deposition of the fine-grained rocks. In particular, the role of precession cycle of 23ka (millennium) is the most obvious. The material and source of fine-grained rock is the basic problem to be solved by the study of fine-grained rocks. The main material composition of the fine-grained rocks in this study area is quartz, carbonate, clay minerals, organic carbon and pyrite. Quartz and clay minerals are mainly derived from continental sources, and a small amount of quartz is authigenic quartz formed during diagenesis; carbonates are mainly of biochemical origin, and a few of them come from land-based sources; most of the organic matter are of type I and type 鈪，
本文编号：2278461
[Abstract]:The study of sedimentary environment of fine-grained rocks has important reference value for prediction of favorable zones of shale oil and exploration and development. In this paper, the fine granulites of the upper member of Sha 4 in Dongying sag with abundant organic matter are taken as the research object. The petrological characteristics, the characteristics of the grain layer, the overall macro sedimentary environment and the controlling factors of the lithofacies combination are analyzed. The sedimentary model and sedimentary system of fine-grained rocks are refined and classified. In the course of the research, the Milankovich cycle and the fine-grained rock are analyzed synthetically in this paper. It is found that the astronomical cycle does have a great influence on the deposition of the fine-grained rocks. In particular, the role of precession cycle of 23ka (millennium) is the most obvious. The material and source of fine-grained rock is the basic problem to be solved by the study of fine-grained rocks. The main material composition of the fine-grained rocks in this study area is quartz, carbonate, clay minerals, organic carbon and pyrite. Quartz and clay minerals are mainly derived from continental sources, and a small amount of quartz is authigenic quartz formed during diagenesis; carbonates are mainly of biochemical origin, and a few of them come from land-based sources; most of the organic matter are of type I and type 鈪，
本文编号：2278461
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