Micro-pore Structure and Gas Accumulation Characteristics of Shale in the Longmaxi Formation, Northwest Guizhou  

作　　者：Bing Xue Jinchuan Zhang Xuan Tang Chao Yang Qian Chen Xiangjie Man Wei Dang 

机构地区：[1]School of Energy Resources,China University of Geosciences,Beijing 100083,China [2]Key Laboratory of Shale Gas Exploration and Evaluation,Ministry of Land and Resources,Beijing 100083,China [3]CNPC Greatwall Drilling Company,Beijing 100101,China

出　　处：《Petroleum Research》2016年第2期191-204,共14页石油研究（英文）

基　　金：This work was funded by National Natural Science Foundation(Grant No.41102088);Project of Department of Land and Resources of Guizhou Province(Grant No.2012GYYQ-001)。

摘　　要：For further study on characteristics of micro-pores in the marine shale reservoirs in Northwest Guizhou,shale samples in the Lower Silurian Longmaxi Formation were selected to investigate effect of micro-pores on the characteristics of gas accumulation in shales,through methods of the argon broad ion beam-field emission scanning electron microscope and the nitrogen adsorption/desorption,analysis on the characteristics of micro-pores and related geochemical analysis.Results show that there are seven types of pores in the Longmaxi Formation shale,including interparticle pores,intraparticle pores,intercrystalline pores,dissolution pores,fossil pores,organic pores,and microfractures,among which the interparticle pores and organic pores are best developed.According to the nitrogen adsorption/desorption curves,the pore structures can be classified into three types,including the cylindrical pores with both opening ends,narrow parallel-plate pores and tapered parallel-plate pores with four opening sides.Diameter of micro-pores ranges from 2 to 64 nm,mainly at 2-6 nm.The diameter of micro-pores(less than 2 nm)ranges from 0.4 to 1.8 nm,The micro-pores with a diameter of 0.4-1.0 nm contribute most to the pore volume.Pore volume is dominated by meso-pores(2-50 nm)with a proportion of 83.1%.The micro-pores and meso-pores make major contribution to the specific surface area of pores with proportions of 20.1%and 79.3%,respectively.The total organic carbon(TOC)is the major factor controlling development of nanopores.Different pore types have different characteristics of gas occurrence and migration,indicating that nanopores provide favorable conditions for the occurrence and microscopic migration of gas in shales.

关 键 词：Northwest Guizhou Longmaxi Formation lower Silurian argon broad ion beam-field emission scanning electron microscope nitrogen adsorption/desorption pore structure 

分 类 号：P61[天文地球—矿床学]