Microscopic characteristics and geological significance of tight dolomite in well Xike-1,Xisha Islands,China  

作　　者：Qin Na Hong Xu Da-peng Su Meng Tao Wei-wei Zhang Zhao-peng Ji Qing Wang 

机构地区：[1]School of Earth Science and Technology,China University of Petroleum,Qingdao 266580,China [2]Qingdao Institute of Marine Geology,China Geological Survey,Ministry of Natural Resources,Qingdao 266071,China [3]Shandong Provincial Key Laboratory of Sedimentary Mineralization and Minerals,Shandong University of Science and Technology,Qingdao 266590,China [4]First Institute of Oceanography,Key Laboratory of Marine Sediments and Environmental Geologic Oceanography,Qingdao 266061,China [5]Ocean National Laboratory,Function Laboratory of Marine Geo-Resource Evaluation and Exploration Technology,Qingdao 266071,China [6]School of Geosciences and Engineering,Shandong University of Science and Technology,Qingdao 266590,China [7]Yangtze University,Wuhan 430100,China

出　　处：《China Geology》2019年第4期458-466,共9页中国地质（英文）

基　　金：This work was supported by the National Natural Science Foundation of China(41106064);the Science and Technology Basic Resources Investigation Program of China(2017FY201407).

摘　　要：A recent study suggests that the deep dolomites in well Xike-1 located more than 1000 m deep have a very low porosity,and no permeability for most of the samples.Given that the largest oil and gas fields in the South China Sea are all composed of biohermal dolomites while the deep dolomites of Xike-1 serve as the caprock formations rather than the reservoirs,this represents the first discovery and is of great theoretical importance.In this paper,core photos of the tight dolomites are presented.Hand specimens description and systematic porosity-permeability reveal a very low porosity,and no permeability for most of the samples.PLM,SEM and XRPD analysis discovered that the dolostones in the deep tight dolomites are quite large in size and euhedral or subhedral in shape.Alizarin red-stained sections are mostly pink in color and have a full coverage,which are considered as evidence for multiple calcite intrusions after the formation of ankerite dolomites.Biological relict textures are developed.The order degree is medium to low.The dolomites could be the product of penecontemporaneous dolomitization.

关 键 词：PERMEABILITY Order degree TIGHT DOLOMITE Rock types Gas oil exploration engineering Xike-1 of Shi ISLAND China 

分 类 号：P618.13[天文地球—矿床学]