西南石油大学学报(自然科学版)

• 地质勘探 • 上一篇    下一篇

四川盆地下志留统龙马溪组底部界线研究

王兴志1,李宜真1,杜洋1,2,胡杨2,李烨1   

  1. 1.“油气藏地质及开发工程”国家重点实验室西南石油大学,四川成都610500
    2. 中国石油川庆钻探工程有限公司地质勘探开发研究院,四川成都610052
  • 出版日期:2014-02-01 发布日期:2014-02-01

Study on Longmaxi Formation Bottom Boundary in Sichuan Basin

Wang Xingzhi1, Li Yizhen1, Du Yang1,2, Hu Yang2, Li Ye1   

  1. 1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploration,Southwest Petroleum University,Chengdu,Sichuan 610500,China
    2. Geological Exploration & Development Institute,Chuanqing Drilling Engineering Co. Ltd.,CNPC,Chengdu,Sichuan 610052,China
  • Online:2014-02-01 Published:2014-02-01

摘要:

针对下志留统龙马溪组底部界线划分问题,在前人研究的基础上,通过对四川盆地及周缘地区的野外剖面和
钻井岩芯的宏观与微观观察以及对录井、测井、分析化验等资料的分析,发现龙马溪组底部界线上下地层具有以下特
征上的差异:五峰组顶部灰质含量较高,腕足类化石丰富,测井曲线上表现为低伽马高电阻率,TOC 值较低,矿物组分
中方解石含量较高;而龙马溪组底部不含灰质,不含腕足类化石,笔石化石丰富,测井曲线上呈高伽马低电阻率,高黏
土和石英含量,TOC 出现峰值。研究认为检测灰质含量和对比电测曲线是现场划分龙马溪组底界最快捷和准确的方
法,能为四川盆地龙马溪组页岩气勘探提供一定的理论基础。

关键词: 四川盆地, 龙马溪组, 底界, 五峰组, 下志留统

Abstract:

In order to solve the partitioning problem on the bottom boundary of lower Silurian Longmaxi Formation,based
on previous researches,with the macroscopic and microscopic observation of outcrops and drilling cores and the analysis of
well logging,mineralogical and geochemical data in Sichuan Basin and its peripheral areas,the differences between Longmaxi
and Wufeng Formation show that there are higher limy content,many brachiopods,low GR and high RT logging values,high
calcite content and lower TOC values in the top of Wufeng Formation,while the bottom of Longmaxi Formation have none
limy content,none brachiopods and abundant graptolites,high GR and low RT logging values,high clay and quartz content,
highest TOC values. The study suggested that the detection of limy content and comparison of log are the fast and accurate
methods of demarcating Longmaxi Formation bottom boundary in practical operation,and it can provide some theoretical basis
for furthermore shale gas exploration in Longmaxi Formation of Sichuan Basin.

Key words: Sichuan Basin, Longmaxi Formation, bottom boundary, Wufeng Formation, lower Silurian