The differences of reservoir features between southern marine shale gas and northern coal-bearing shale gas in China
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Abstract
Marine shale gas has been developed widely in southern China,which proves better prospects.While researches about coal-bearing shale gas remain fewer.This paper mainly takes marine shale gas in Fenggang district of Guizhou province and coal-bearing shale gas in Qinshui basin as an example,contrasting reservoir features between four factors,including the kerogen type,total content of organic carbon,mineral composition and pore structure,then points out the reservoir differences to analysis the shale under the control of depositional environment.The studies show that there exists both differences and similarities between them.Marine shale gas reservoir possesses typeⅠand typeⅡkerogen,however, coal-bearing shale gas reservoir mostly owns type Ⅲ kerogen.In addition,marine shale gas reservoir has higher TOC content,brittle mineral content and larger pore surface.On the other hand,these two kinds of shale develop organic pores.Meanwhile,nitrogen isothermal adsorption curves are consistent with typeⅣ,and mesopores play a dominant role in pores.However,due to the thin layer thickness and poor continuity of coal-bearding shale,the exploration of coal bearing shale gas can not copy the pattern of marine shale gas.It is considerable that coal bearing shale gas can be co-exploit with the tight sandstone gas and coalbed methane to improve resource utilization and achieve economic exploitation.
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