西藏措勤盆地保吉地区上二叠统—下三叠统木纠错组显微荧光特征及油气勘探建议  

The Micro-fluorescence Characteristics of the Upper Permian–Lower Triassic Mujiucuo Formation and Suggestions for Oil-gas Exploration in Baoji Area of Coqen Basin, Tibet

作　　者：何继富[1,2] 纪占胜 武桂春[3] 刘景彦[1] 孙倩[1,2] 石秋圆 李浩 刘振宇[4] 郭安臣 侯召硕[4] 李东泽[4] HE Ji-fu;JI Zhan-sheng;WU Gui-chun;LIU Jing-yan;SUN Qian;SHI Qiu-yuan;LI Hao;LIU Zhen-yu;GUO An-chen;HOU Zhao-shuo;LI Dong-ze(China University of Geosciences(Beijing),Beijing 100083;Chinese Academy of Geological Sciences,Beijing 100037;Key Laboratory of Stratigraphy and Paleontology,Ministry of Land and Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037;Geological Survey Institute of Jilin Province,Changchun,Jilin 130102)

机构地区：[1]中国地质大学(北京),北京100083 [2]中国地质科学院,北京100037 [3]中国地质科学院地质研究所,国土资源部地层与古生物重点实验室,北京100037 [4]吉林省地质调查院,吉林长春130102

出　　处：《地球学报》2018年第4期463-473,共11页Acta Geoscientica Sinica

基　　金：国家自然科学基金项目(编号:41472030);科技基础性工作专项(编号:2015FY310100);中国地质调查局基础性公益性矿产地质调查项目(编号:DD20160120-02;DD20160120-04;DD20160126);中国地质科学院基本科研业务费项目(编号:J1607)联合资助~~

摘　　要：本次研究的西藏班戈县保吉地区的木纠错组以白云岩为主要岩性特征,出露厚度大于870 m,顶底不全。本次研究在该组共采集和制作岩石薄片95片,在透射光下见到22片具有有机质污染的现象,笔者对这些具有有机质污染现象的岩石薄片进一步开展了荧光显色的验证工作,并确认其为含油层。根据上述结果,统计剖面含油地层厚度约有114 m。木纠错组显微荧光颜色主要呈黄绿色、绿色,少部分呈黄色和黄橙色,其中以黄绿色最为常见。荧光颜色指示岩石中的沥青类型主要为油质沥青和胶质沥青。这些沥青分布于晶隙、裂缝中或呈弥散状。在地表可见地层溶洞发育,露头见针状溶孔,岩石薄片中常见网络状张开裂隙,晶间孔和粒间溶孔,晶间孔网络状连接。据初步统计,薄片面孔率最大可达22.7%,最小为11.8%,平均为16.23%,因此该套白云岩的孔隙性和连通性较好。措勤盆地的木纠错组保存条件较好,被三叠系、侏罗系和白垩系地层覆盖于地下。结合对研究区地层分布及构造情况的认识,建立了纳木错西岸木纠错组油气勘探模型。Dolomite is the main lithologic facies of the Mujiucuo Formation at the Baoji Area,Bange County,Tibet,and the Mujiucuo Fm is exposed more than 870 meters in thickness without top and bottom.Totally 95 pieces of rock slices were investigated,the phenomenon of organic contamination was found in 22 pieces of the rock slices under the transmitted light,therefore,the author conducted microscopic fluorescence analysis on the 22 rock slices and confirmed their oiliness.Based on the above result,the author calculated the thickness of the oil-bearing layers to be about 114 m.The main fluorescent colors of the Mujiucuo Fm are yellow-green and green,minor portion are yellow or yellow-orange,and yellow-green is the most common color.Fluorescent color indicates that the types of asphalt in the rocks are mainly oily asphalt and colloidal asphalt.These bitumen distribute in the gaps,cracks or diffuse in the whole slice.Karst caves and needle holes can be seen in the outcrops.Structural crack,network-like intercrystalline pore and intergranular dissolution pore can be seen in the rock slices.According to preliminary statistics,the largest plane porosity can up to 22.7%,the minimum plane porosity is 11.8%and the average is 16.23%,therefore,the dolomite has a good porosity and connectivity.The Mujiucuo Formation in the Coqen Basin is well preserved because it is covered by Triassic,Jurassic,and Cretaceous strata in vast area.Based on the analysis of the stratigraphic distribution and structure of the study area,an oil-gas exploration model for the Mujiucuo Formation is proposed too.

关 键 词：上二叠统-下三叠统 木纠错组 显微荧光 油气勘探 措勤盆地 

分 类 号：P534.46[天文地球—古生物学与地层学] P534.51[天文地球—地质学]