Combination characteristics of unconventional gas in coal measure in the west margin of Ordos Basin

Multiple values of coal resources were the paragenetic association and symbiotic mining potential of various minerals in coal measures. In addition to coal itself,the closely related formation and distribution of unconventional natural gases (coal measure gases),including coalbed methane,shale gas,tight gas,had attracted a widespread atten- tion. Study on the combination modes of these unconventional natural gases in coal measure can be useful to the comprehensive exploration and integrated development. Based on the study of formation conditions of unconventional gas in the coal measure in the west margin of Ordos Basin,the favorable segment of unconventional gas in the coal measure can be identified by the analysis of lithological combination,sedimentary sequence and test data. It shows that the up- per member of Taiyuan formation,the lower member of Shanxi Formation,and the first three members of Yan’ an for- mation have the exploration potential of unconventional gas in the coal measure. For example,876-897 m in the third members of Yan’an formation of drill JM107,near the Coal seam 4 and 4 upper,is the favorable segment of unconven- tional gas in the coal measure. Through these,three combination modes of unconventional gas in the coal measure can be formed and their coupling mechanism is preliminarily discussed.