贵州大方地区牛蹄塘组一段富有机质泥页岩孔隙特征研究

Study on Pore Characteristics of Organic-rich Mud Shale in the First Member of Niutitang Formation in DafangArea,Guizhou

以扫描电镜、氮气吸附实验为基础,结合物性、TOC、Ro分析对贵州大方地区下寒武统牛蹄塘组一段富有机质泥页岩孔隙类型及特征和甲烷吸附能力的影响因素进行了研究,其结果显示:①富有机质页岩主要为炭质泥岩、炭质含粉砂泥岩、炭质页岩,有机质丰度和热演化程度较高,具备较强的生烃潜力;②孔隙类型发育有机质孔和晶间孔、溶蚀孔、铸模孔和微裂缝,有机质孔连通性较好,总体具有低孔一低渗、超低渗型储层特征;③有机碳含量和成熟度升高,有利于有机质孔隙发育,提高甲烷吸附能力。

Based on Scanning Electron Microscopy and Nitrogen Adsorption experiments,combined with physical properties,TOC and Ro analysis,the pore types and characteristics of organic-riched mud shale in the first member of the Lower Cambrian Niutitang Formation and the influencing factors of methane adsorption capacity in Dafang area,Guizhou were studied.The results show that:Firstly,the organic-riched shale is mainly carbonaceous mudstone,carbonaceous silt-bearing mudstone,and carbonaceous shale,with high organic matter abundance and thermal evolution degree,and has strong hydrocarbon generation potential.Secondly,the pore type develops organic pores and intercrystalline pores,dissolution pores,mold pores and micro-fractures.The organic pores have good connectivity,and generally have the characteristics of low porosity-low permeability and ultra-low permeability reservoirs.Thirdly,the increase of organic carbon content and maturity are conducive to the development of organic matter pores and the improvement of methane adsorption capacity.