The western edge of the Xuefeng Uplift,the Cambrian Niutitang Formation,is a late uplifted base-ment uplift zone and experienced a relatively short period of deep burial,and the degree of organic matter evolu-tion is generally favorable for the preservation of shale gas,which is a good shale gas resource potential has an effect.In this paper,it takes the Tongye 1 well in northeast Guizhou as an example,and explores the relationship between each parameter and the difference in gas content by analyzing the changes in the data of TOC total or-ganic carbon(TOC),organic matter maturity Ro,the sediment thickness,can be analyzed and thickness of high-grade shale in the Cambrian Niutitang formation and the Aurignacian Laobao formation in longitudinal and transverse black rock systems.Based on the analytical results of the Tongye 1 well,the results show the follow-ing:the organic-rich shale of the Niutitang Fformation is about 56 m thick,the average TOC content is 4.49％;the average Ro value is 3.35％,and the overall ripeness has reached the overripe stage;the types of kerogen are all type Ⅰ,and the potential of hydrocarbon production is good.The brittle mineral content is＞50％,the average porosity of the reservoir is 0.81％,and the average permeability is 0.37 ×10-3mD,which is low,and it is one of the low porosity and extremely low reservoirs Permeability.The shale pores are largely dominated by isolated,ir-regularly shaped dissolution pores,with poor preservation of organic material pores and poor pore connectivi-ty.The gas content test shows that the Niutitang formation generally has a lower gas content,the highest is only 0.07 m3/t,and the highest is only 0.33 m3/t in the Laobao formation,and the Laobao formation has better gas content than the Niutitang formation.The study shows that the higher the degree of thermal evolution of organic matter in the Niutitang Formation,the fewer of organic matter pores number and soluble pores and the worse the connectivity of the reservoir;the lithology of the reservoir is dense and lacks space,which is the main factor for the weak gas content of the Niutitang Formation.The Laobao Formation has relatively good shale gas reserves,probably because the organic matter at the bottom of the Niutitang formation is modified by the late stage of dia-genesis,and the shale gas is centrally preserved along the fractures,which has a certain value for research,ex-ploration and development.
Geological characteristics of shale gasGas content Tongye 1 wellNortheast Guizhou
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