COAL-DERIVED GAS AND ITS RESERVIOR CONDITIONS IN YAOJIE MINING AREA, GANSU PROVINCE

Dark mudstone、oilshale、coal seam and marl in coal-bearing formation are hydrocarbon source rock which originates natural gas. In this paper, the authors studied their geochemical and coal petrological properties, and determined genetic type of the natural gas in Yaojie mining area on the basis of this. Coal-derived gas reservoired in Yaojie mining area has evolved from hydrocarbon source rock during very long geological history. It was reservoired in small opening of sandstone or bedrock crack in coal-bearing formation. It can be formed small type oil-gas reservoir in contributed ressrvoir oil-gas trap.