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建南气田位于开江—梁平海槽和城口—鄂西海槽之间,长兴组在气田北高点发育生物礁,生物骨架发育,岩性为生物礁次生白云岩;飞仙关组南高点气藏发育台内内碎屑——核形石灰岩、鲕粒灰岩、白云岩及细粉晶灰岩。二者储集类型均为裂缝—孔隙型。因此,建南气田为典型的台内礁滩气田。对建南气田的天然气及气源岩特征进行剖析,有助于加强对台内礁滩气藏的认识。通过天然气组分特征及其与碳同位素的关系分析,结合硫化氢含量与白云岩平面分布的关系,认为建南气田长兴组、飞仙关组的干气不受地幔无机成因气影响,主要为油型气及煤型气的混合气,且遭受TSR改造。利用天然气CH4碳同位素与成熟度关系模型,综合分析认为建南气田长兴组、飞仙关组天然气气源主要为二叠系油型烃源岩及煤型烃源岩,而志留系烃源岩只有少量贡献。
Jiannan gas field is located between Kaiping-Liangping Trough and Chengkou-Exihai Trough. Changxing Formation develops bio reefs in the northernmost point of the gas field with bio-skeleton development and lithology as bio-reef secondary dolomite. Feixianguan Formation south High gas reservoirs develop intraplate detritus - kalyan limestone, oolitic limestone, dolomite and finely crystalline limestone. Both reservoir types are fracture-pore type. Therefore, Jiannan gas field is a typical intracontinental reef gas field. Analyzing the characteristics of natural gas and gas source rock in Jiannan gas field will help to enhance understanding of the gas reservoirs in the reef beach in Taiwan. Based on the characteristics of natural gas components and their relationship with carbon isotopes and the relationship between the content of hydrogen sulfide and the distribution of dolomite, the dry gas in Changxing Formation and Feixianguan Formation of Jiannan Gas Field is not affected by inorganic gas genesis of the mantle, mainly Oil gas and coal gas mixture, and subject to TSR transformation. Based on the model of CH4 carbon isotope and its relationship with maturity, the natural gas sources of Changxing Formation and Feixianguan Formation in Jiannan Gasfield are mainly Permian oil source rocks and coal source rocks, and the Silurian hydrocarbon source Rock only a small contribution.