川南海相页岩岩石相类型及“甜点”分布——以长宁双河剖面五峰组—龙马溪组为例  

Lithfacies and“sweet spot”interval of marine shale in southern Sichuan:A case study of Shuanghe Outcrop in Wufeng-Longmaxi Formation,Changning

作　　者：王红岩[1,2] 董大忠 施振生[1,2] 邱振 卢斌[1,2] 邵男 孙莎莎[1,2] 张素荣 WANG Hongyan;DONG Dazhong;SHI Zhensheng;QIU Zhen;LU Bin;SHAO Nan;SUN Shasha;ZHANG Surong(PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China;National Energy Shale Gas R&D(Experiment)Center,Beijing 100083,China;Technology Administration Department,PetroChina Company Limited,Beijing 100007,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]国家能源页岩气研发(实验)中心,北京100083 [3]中国石油天然气股份有限公司科技管理部,北京100007

出　　处：《油气藏评价与开发》2022年第1期68-81,94,共15页Petroleum Reservoir Evaluation and Development

基　　金：中国石油科技部重大专项“海相页岩气勘探开发技术研究”(2021DJ1901)。

摘　　要：综合应用笔石带标定、全大薄片照相、常规薄片光学显微镜观察、TOC(总有机碳含量)测试、X-衍射全岩组分测试及场发射扫描电镜观察等手段,系统研究了长宁页岩气示范区长宁双河剖面五峰组—龙马溪组黑色页岩的物质组成及分布、层理特征、物性及岩石相。研究结果表明,川南长宁双河剖面五峰组—龙马溪组黑色页岩主要为硅质页岩、钙质页岩和混合页岩,石英、碳酸钙和黏土矿物平均值分别为42.5%、37.4%和14.9%,含有少量斜长石(平均2.5%)、黄铁矿(平均2.7%)和有机质(平均值5.6%)。黑色页岩发育泥纹层和粉砂纹层,2类纹层可构成递变型水平层理、均质层理、条带状粉砂型水平层理、砂泥递变型水平层理和砂泥薄互层型水平层理5类层理类型。五峰组发育递变层水平层理和均质层理,龙马溪组发育条带状粉砂型水平层理、砂泥递变型水平层理和砂泥薄互层型水平层理。综合页岩矿物组成和层理类型,共划分出11类岩石相类型。长宁双河剖面“甜点”段分布于LM1段,发育条带状粉砂型水平层理页岩岩石相。“甜点”段具有高TOC含量和高硅质含量、高孔隙度、高渗透率及高水平渗透率/垂直渗透率比值、高有机质孔含量等特征。With the comprehensive application of the photography of full thin section,the optical microscope observation of small thin sections,TOC test,whole rocks X-ray composition test,physical property analysis and the observation of field emission scanning electron microscope,Ordovician Wufeng Formation amd Silurian Longmaxi Formation in Shuanghe Outcrop in Changning area are analyzed systematically.The results show that the black shale of Wufeng-Longmaxi Formation in Shuanghe Outcrop of Changning area in southern Sichuan Basin is mainly siliceous shale,calcareous shale and mixed shale,and the average values of quartz,calcium carbonate and clay minerals are 42.5%,37.4%and 14.9%,respectively,containing a small amount of plagioclase(average 2.5%),pyrite(average 2.7%)and organic matter(average 5.6%).The black shale develops mud laminae and silty laminae,and these two types of laminae are composed of five bedding types:graded horizontal bedding,homogeneous bedding,banded silty sand horizontal bedding,sand mud graded horizontal bedding and sand mud thin interbedded horizontal bedding.Progressive horizontal bedding and homogeneity bedding are developed in Wufeng Formation,while strip silty sand horizontal bedding,sand-mud progressive horizontal bedding and sand-mud thin interbedded horizontal bedding are developed in Longmaxi Formation.On the basis of mineral composition and bedding types,eleven types of lithofacies are divided.LM1 member,which is the“sweet spot”interval in Shuanghe Outcrop in Changning area,is characterized by high TOC content,high siliceous content,high porosity,high permeability,high horizontal/vertical permeability ratio and high organic pore content.The strip silty sand horizontal bedding develops here.

关 键 词：层理 岩石相 黑色页岩 龙马溪组 五峰组 四川盆地 

分 类 号：TE121[石油与天然气工程—油气勘探]