摘要
In recent years,the domestic study on continent and marine-continental transitional facies shale gas has been affected greatly by significant research achievements of overseas marine-facies shale gas exploration and development.In order to study the shale gas exploration potential of Carboniferous Benxi Formation in Ordos Basin,organic-rich shale samples from Benxi Formation were employed to test their organic geochemistry,physical properties and isothermal adsorption and other natures.Furthermore,parameters obtained in this study were employed to estimate the exploration potential of these shales by applying mathematical statistics and analyzing logging response characteristics.The result shows that the effective shale thickness of Benxi Formation varies greatly,its TOC is greater than 1% in general and is 2.7% on the average,organic matter types are mainly type III and type II2 with a little type I and type II1,vitrinite reflectance averages 1.52%,and shale-gas adsorption content is 0.98m3/t on the average.These indicate that Benxi Formation has essential conditions for the shale-gas reservoir formation.In terms of the effective thickness of mud shales,organic matter content and type,degree of thermal evolution,gas content and deep burial,favorable prospect areas of Benxi Formation shale gas should be mainly located in the northwest corner of Tianhuan depression,the northeast corner of Shaanbei slope and the central-southern part of Ordos Basin.