川西北龙岗西气田长兴组和飞仙关组天然气来源

Natural Gas Sources of Changxing Formation and Feixianguan Formation in Longgang West Gas Field,Northwest Sichuan

在川西北地区龙岗西气田已有多口井钻穿长兴组和飞仙关组地层并获工业气流,近期完钻的剑探1井在飞仙关组可见良好的油气显示,展示较大的勘探开发潜力。根据天然气组成及碳同位素、烃源岩-储层沥青生物标志化合物对比,认为龙岗西气田长兴组和飞仙关组天然气烃类气体以甲烷为主,重烃含量低,干燥系数大;具有相似的碳同位素组成,其中甲烷同位素变化大,乙烷同位素较重;天然气主要来源于上二叠统吴家坪组和大隆组烃源岩。

In longgangxi gas field in Northwest Sichuan,many wells have drilled through Changxing Formation and Feixianguan Formation and obtained industrial gas flow.Jiantan 1 well,which has been drilled recently,has seen good oil and gas display in Feixianguan Formation,showing great exploration and development potential.Based on the comparison of natural gas composition,carbon isotope and source rock reservoir asphalt biomarker,this paper considers that the natural gas hydrocarbon gas of Changxing Formation and Feixianguan Formation in Longgang West gas field is mainly methane,with low heavy hydrocarbon content and high drying coefficient;It has similar carbon isotope composition,in which methane isotope changes greatly and ethane isotope is heavier;The natural gas mainly comes from the source rocks of Wujiaping formation and Dalong formation of Upper Permian.