四川盆地及周缘奥陶系五峰组-志留系龙马溪组页岩生物地层及其储集层特征  

Biostratigraphy and reservoir characteristics of the Ordovician Wufeng-Silurian Longmaxi shale in the Sichuan Basin and surrounding areas,China

作　　者：王红岩[1,2] 施振生 孙莎莎[1,2] WANG Hongyan;SHI Zhensheng;SUN Shasha(PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China;National Energy Shale Gas R&D(Experiment)Center,Langfang 065007,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,河北廊坊065007

出　　处：《石油勘探与开发》2021年第5期879-890,共12页Petroleum Exploration and Development

基　　金：国家科技重大专项“大型油气田及煤层气开发”(2017ZX05035-001)。

摘　　要：通过单剖面笔石鉴定、笔石带划分、等值线图编制及页岩矿物成分、TOC和纹层特征分析,系统研究四川盆地及周缘奥陶系五峰组—志留系龙马溪组生物地层及其储集层特征。结果表明,四川盆地及周缘五峰组—龙马溪组发育笔石带WF1—WF4和LM1—LM9,不同笔石带可用岩性和电性特征标定。不同笔石带页岩分布呈现西南和东北2大沉积中心,且矿物成分、TOC和纹层类型存在差异。笔石带WF2下部和WF4发育含(贫)有机质块状层理混合页岩,笔石带WF1—WF2上部及WF3发育含有机质水平层理混合页岩,笔石带LM1—LM4发育富(含)有机质水平层理硅质页岩,LM5—LM9发育贫有机质水平层理混合页岩。页岩矿物成分、TOC及层理类型受控于古气候、古水体氧化-还原条件和古沉积速率。笔石带WF1—WF2下部,水体由于温暖富氧,故块状层理发育、硅质含量和TOC值低。笔石带WF4水体由于较凉、富氧,故块状层理发育、钙质含量高、TOC值低。笔石带WF2上部、WF3、LM1—LM4水体由于贫氧、沉积速率低,故富有机质硅质页岩水平层理发育,粉砂纹层含量高。笔石带LM5—LM9水体由于富氧、沉积速率过高,故TOC值和硅质含量低、粉砂纹层含量高。图6表2参38。Through graptolite identification in profiles,graptolite zone division,contour map compilation,and analysis of mineral composition,TOC content,lamina distribution features of shale samples,the biostratigraphic and reservoir characteristics of Ordovician Wufeng Formation-Silurian Longmaxi Formation in the Sichuan Basin and surrounding areas are sorted out.There are 4 graptolite zones(WF1 to WF4)in Wufeng Formation and 9(LM1 to LM9)in Longmaxi Formation,and the different graptolite zones can be calibrated by lithology and electrical property.The shale layers of these graptolite zones have two depocenters in the southwest and northeast,and differ somewhat in mineral composition,TOC,and lamina types.Among them,the graptolite zones of lower WF2 and WF4 are organic matter lean massive hybrid shale,the upper part of WF1-WF2 and WF3 have horizontal bedding hybrid shale with organic matter,the LM1-LM4 mainly consist of organic-rich siliceous shale with horizontal bedding,and the LM5-LM9 graptolite zones consist of organic-lean hybrid shale with horizontal bedding.The mineral composition,TOC and lamina types of shale depend on the paleo-climate,paleo-water oxidation-reduction conditions,and paleo-sedimentation rate during its deposition.Deposited in oxygen-rich warm water,the lower parts of WF1 and WF2 graptolite zones have massive bedding,lower TOC and silicon content.Deposited in cooler and oxygen rich water,the WF4 has massive bedding,high calcium content and low TOC.Deposited in anoxic water at low rate,the upper part of WF2,WF3,and LM1-LM4 are composed of organic rich siliceous shale with horizontal bedding and high proportion of silt laminae.Deposited in oxygen rich water at a high rate,the graptolite zones LM5-LM9 have low contents of organic matter and silicon and high proportions of silt lamina.

关 键 词：笔石带 页岩 储集层特征 奥陶系五峰组 志留系龙马溪组 生物地层 四川盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]