Xi’an Research Institute of China Coal Technology & Engineering group Corp. ,Xi’an　 710054,China

鄂尔多斯盆地黄陵地区在煤田勘探、建井和采煤中,发现了小规模的油气显示,推测该区域煤层中存在油型气,这一点与煤层气作为自生自储型资源的常规认识不同。为进一步验证这一推测,从煤层顶板、煤层、底板及采空区采集220组气体样品,开展气体组分、甲烷碳同位素δ13C1、甲烷氢同位素δD、乙烷碳同位素δ13C2的测试。测试结果表明,煤层中气体来源为煤成气和油型气组成的混合气,进一步利用Schoell图版分析,煤层及其围岩中油型混合气主要为裂解凝析气、生物气和石油伴生气。这些气体来源于下部三叠系延长组泥页岩,通过地层中的断层与裂缝,向上运移至侏罗纪煤系中储存下来,提高了煤层含气性。

There are oil and gas showing in the coal exploration,shaft building and exploitation in the southern Ordos basin,associated with oil type gas,which is different from authigenic coal reservoir. In order to verify this speculation, 220 gas samples are collected from coal seam,roof,floor and the gob and tested,including heavy hydrocarbon content C2+ ,methane carbon isotope δ13 C1 ,methane hydrogen isotope δD and ethane carbon isotope δ13 C2 . The result shows that the origins of coalbed methane are mixed by coal-derived gas and oil type gas. By Schoell plate analysis,oil type mixed gas is composed by pyrolysis condensate gas,biogenic gas and oil-associated gas in coal seams and its surround- ing rocks. The oil type gas migrated from Yanchang formation shale in Triassic system by faults and fissures,and which added the gas content in the coal reservoir.

LI Guihong. Source identification of the Jurassic coalbed gas in Huangling area,Ordos basin[ J]. Journal of China Coal Society,2018,43 (4):1052-1057.