摘要
鄂尔多斯盆地三叠系延长组长7_(3)亚段沉积的富有机质泥页岩中,频繁发育的纹层导致页岩层系非均质性强,进而对泥页岩的储集特征及含油性造成影响。本文基于典型的纹层页岩样品,利用游标卡尺对岩心上的纹层进行定量测量,结合显微镜下薄片鉴定、总有机碳测定、X射线衍射矿物分析及岩石热解实验,对长7_(3)亚段页岩纹层的发育特征、纹层类型划分及纹层在单井上的纵向展布规律进行了研究。研究结果表明,宏观岩心上发育的纹层单层厚度一般分布在0.4~5.0 mm,纹地比(纹层总厚度/统计段岩心长度)介于5.7%~16.8%,纹层发育频率非均质性强。显微镜下依据纹层沉积构造的形态划分为6类,分别为3种具有连续形态沉积特征的平直型纹层、波纹型纹层、粒序型纹层及3种非连续形态沉积特征的透镜状纹层、斑状纹层、弱纹层,不同形态纹层页岩的矿物组成及有机质丰度差异明显。依据纹层内部的微观物质组成将其类型主要划分为有机质纹层、长英质纹层及凝灰质纹层;按照不同纹层垂向的叠置规律,将纹层组合划分为均质泥岩、长英质纹层型页岩与凝灰质纹层型页岩。单井上,纹层分布具有非均质性,不同纹层的发育频率与黏土矿物含量、TOC及OSI的变化呈一定的规律性变化。
In the organic-rich shale deposited in the Chang 7_(3) sub-member of the Triassic Yanchang Formation in the Ordos Basin,the frequent laminae lead to strong heterogeneity of shale series,which in turn affects the reservoir characteristics and oil-bearing property of the shale.Based on typical laminated shale samples,this paper quantitatively measured the laminae in the core with vernier calipers,and studied the development characteristics,laminae types and vertical distribution of laminae in the Chang 7_(3) sub-member shale by combining microscopic thin section identification,total organic carbon determination,X-ray diffraction mineral analysis and rock pyrolysis experiments.The results show that the thickness of single layers of the laminae developed on the macro core is generally between 0.4 and 5.0 mm,and the ratio of the laminae to the core(the total thickness of the laminae/the core length of the statistical section)is between 5.7%and 16.8%,and the development frequency of the laminae is highly heterogeneous.Microscopically,it is divided into six types according to the morphology of laminae sedimentary structures,which are three kinds of straight laminae,corrugated laminae,granular laminae with continuous clay morphological sedimentary characteristics and three kinds of lenticular laminae,mottled laminae and weak laminae with discontinuous morphological sedimentary characteristics.The mineral composition and organic matter abundance of shale with different morphologies are obviously different.According to the microscopic material composition inside the laminae,they are mainly divided into organic laminae,felsic laminae and tuffaceous laminae,and according to the vertical superposition of different laminae,the laminated combinations are divided into homogeneous mudstone,felsic laminated shale and tuffaceous laminated shale.In a single well,the distribution of laminae is heterogeneous,and the development frequency of different laminae changes regularly with the changes of clay mineral content,total organic carb
作者
安成
柳广弟
孙明亮
游富粮
王子昕
曹玉顺
AN Cheng;LIU Guangdi;SUN Mingliang;YOU Fuliang;WANG Zixi;CAO Yushun(College of Geosciences,China University of Petroleum-Beijing,Beijing 102249,China;State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum-Beijing,Beijing 102249,China)
出处
《石油科学通报》
CAS
2023年第2期125-140,共16页
Petroleum Science Bulletin
基金
中国石油天然气集团有限公司—中国石油大学(北京)战略合作科技专项(ZLZX2020-02)资助。
关键词
纹层
纹层组合
泥页岩
长7_(3)亚段
纹层演化
laminae
laminae combination
mud and shale
Chang 7_(3)sub-member
laminae evolution
