下扬子地区下寒武统富有机质页岩的岩相与沉积环境

发布时间：2018-05-16 15:17

本文选题：岩相 + 富有机质页岩　；参考：《地质科技情报》2017年05期

【摘要】：识别不同的页岩岩相是非常规页岩油气勘探开发的关键步骤。下扬子地区下寒武统海相页岩沉积于深水的被动大陆边缘盆地,为潜在的页岩气勘探目的层系。划分出下扬子地区XY1井下寒武统富有机质页岩的岩相类型,并确定了岩相与有机质丰度(TOC)的关系。根据沉积物的岩性、沉积构造、矿物组分、含有物、伽马测井等特征,识别出下寒武统富有机质页岩段的4种岩相:(1)纹层状硅岩岩相;(2)含海绵骨针硅质页岩岩相;(3)灰质泥岩岩相;(4)纹层状灰岩岩相。XY1井下寒武统富有机质页岩形成于深水下斜坡相-盆地相。纹层状硅岩岩相和含海绵骨针硅质页岩岩相沉积于盆地相,沉积界面位于风暴浪基面和碳酸盐岩补偿深度(CCD)之下,缺氧的还原环境有利于有机质保存,纹层状硅岩w(TOC)10%,含海绵骨针硅质页岩w(TOC)为2%~10%。纹层状灰岩岩相和灰质泥岩岩相沉积于下斜坡相,其沉积界面位于碳酸盐岩补偿深度(CCD)附近或之上,不利于有机质富集,w(TOC)一般小于2%,表明岩相控制了有机质丰度(TOC)。
[Abstract]:Identifying different shale facies is a key step in unconventional shale oil and gas exploration and development. The Lower Cambrian marine shale is deposited in deep water passive continental margin basin in Lower Yangtze area, which is a potential shale gas exploration system. The lithofacies types of organic matter rich shale of XY1 downhole Cambrian in Lower Yangtze area are divided and the relationship between lithofacies and organic matter abundance is determined. According to the lithology of sediments, sedimentary structures, mineral components, contents, gamma logging and other characteristics, Four types of lithofacies of the lower Cambrian organic matter rich shale formation were identified. The lithofacies of stratified siliceous rocks with spongy bone needle and siliceous shale bearing spongy bone were identified. The lithofacies and lithofacies of gray-mudstone were identified. 4) the lithofacies of XY1 downhole Cambrian rich organic matter shale were formed in deep depth. Underwater slope facies-basin facies. The lithofacies of lamellar silicolites and siliceous shale facies containing spongy bone needle are deposited in basin facies, and the sedimentary interface is below the storm wave surface and carbonate compensation depth (CCDD). The anoxic reduction environment is favorable for the preservation of organic matter. The laminated layered siliceous rock consists of a spongy bone needle, siliceous shale, and a spongy bone needle. Lamellar limestone facies and lime-mudstone facies are deposited in the lower slope facies. The sedimentary interface is located near or above the carbonate compensation depth (CCDC), which is not conducive to the enrichment of organic matter and is generally less than 2%, indicating that the lithofacies control the abundance of organic matter.
【作者单位】：中石化江汉石油工程有限公司页岩气开采技术服务公司;
【分类号】：P618.13

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