Unconventional Gas Reservoir Occurrence Regularities And Geological Control Of Coal Measure In Qinshui Basin

Co-exploration and co-mining of the unconventional natural gases in coal series,including coalbed methane(CBM),tight sandstone gas and shale gas,is leading the direction of unconventional natural gas industry in China,but the research on the region superposed development of three kinds of conventional reservoirs is still in its infancy.Therefore,based on previous results and dates review,the sequence sratigraphic framework of the Permo-Carboniferous coal measures in Qinshui Basin has bean built.Depend on fine description of typical borehole sections and gas-bearing properties,petroleum system and types of unconventional reservoirs have been discussed.In terms of cross profile contrast and flat distribution graphs,the spatial distribution regularity of different reservoirs has been summarized.From the points of deposit control and sequence stratigraphic framework,the geological control mechanism of different reservoirs has been analyzed.The result shows that there are 6 third-class sequences and 12 system tracts from Shanxi formation to Taiyuan formation.The strata can be divided into 4 petroleum systems vertically,including 5 available gas-bearing layers.All the coal-series unconventional reservoirs can be divided into 5 different types,which are single coal reservoir,single shale reservoir,coal-shale mixed reservoir,sand-shale mixed reservoir and coal-shale-sand mixed reservoir.Single coal reservoir is mainly developed in TST of SQ1 and HST of SQ5,single shale reservoir is mainly developed in HST of SQ4,coal-shale mixed reservoir is mainly developed in SQ1,SQ3 and SQ5,sand-shale mixed reservoir is mainly developed in SQ3 and SQ6,coal-shale-sand mixed reservoir is developed in all these strata sequences.