川西地区白马庙气田侏罗系的天然气，以往大都认为是来自上三叠统煤系地层，但对具体来源于上三叠统哪一个层位却存在较大的分歧。
Most of people considered that the natural gas in Jurassic in Baimamiao gas field in West Sichuan Basin came from the coal measure strata of Upper Triassic in the past.
分析了该天然气的成因，指出它主要是来自储层原油的菌解，另外还有侏罗系浅部煤系地层生物气的贡献。
The formation mechanism of gas is analyzed in the paper, the majority of gas derives reservoir oil degradation gas, the minority derives the biogenic methane in Jurassic coal stratum .
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