准噶尔盆地南缘天然气分布较为广泛,在3排背斜带均有分布。该区天然气在组分上以烃类为主,其中甲烷占主导;普遍含有氮气和二氧化碳。准噶尔盆地南缘天然气均为典型热成因气,主要为源自中、下侏罗统成熟—过成熟煤系烃源岩的煤成气,其中第一排背斜带和第二排背斜带天然气均为典型高—过成熟阶段煤成气,第三排背斜带独山子背斜下古近统和呼图壁背斜所有气样也是该类型,第三排背斜带其余煤成气样为典型成熟阶段煤成气。准噶尔盆地南缘煤成气普遍具有碳同位素部分倒转的特征,其主要由于同型不同源(侏罗系不同层位)气的混合,也有部分由于细菌氧化作用(古牧地背斜)或油型气和煤成气的混合(齐古和安集海)。该区油型气样品较少,目前发现的2个油型气样品位于卡因迪克油田白垩系和独山子油气田古近系,分别为成熟和高—过成熟阶段油型气,来自白垩系和二叠系腐泥型烃源岩。齐古背斜二叠系和三叠系中煤成气主要是由断裂下盘埋深较大的下侏罗统八道湾组煤系烃源岩所生成,而侏罗系中煤成气则主要来自中侏罗统西山窑组和下侏罗统三工河组烃源岩,其埋深相对较浅,成熟度相对较低,因此生成的天然气碳同位素值和甲烷含量均相对较小。 Natural gas in the southern margin of Junggar Basin is more widely distributed and distributed in three rows of anticlines. The natural gas in the area is dominated by hydrocarbons, with methane dominated; nitrogen and carbon dioxide are common. The natural gas in the southern margin of Junggar Basin is a typical thermogenic gas and is mainly derived from coal-derived gas of mature and over-mature coal-derived source rocks in Middle and Lower Jurassic. The first row of anticlines and the second row of anticlines The natural gas is all typical high-overmaturity coal-to-gas, and all the gas samples in the anticlines of the Dushanzi anticline and the anticlines of the Hutubi anticline in the third row are also of the same type. Like a typical mature stage of coal into gas. The coal-forming gas in the southern margin of the Junggar Basin generally has the characteristics of partial inversion of carbon isotopes, mainly due to the mixing of different isotopic sources (different layers of the Jurassic) gas, and partly due to bacterial oxidation (ancient Muti anticline) or oil type Mixture of gas and coal gas (Qiugu and Anjihai). There are few oil gas samples in this area, and the two oil gas samples found at present are located in the Cretaceous of the Cainedik oil field and the Paleogene of the Dushanzi oil and gas field, which are the mature and high-maturity oil-gas types from Cretaceous and Permian sapropelic source rocks. The Qiage anticline Permian and Triassic coal-to-coal gas are mainly formed from the Lower Jurassic Badaowan Formation coal-bearing source rocks with larger buried depths of fractures, while the Jurassic coal-to-gas formation Mainly from the source rocks of the Xishanyao Formation and the Lower Jurassic Sangonghe Formation in the Middle Jurassic. The burial depth is relatively shallow and the maturity is relatively low, so the carbon isotope value and methane content of the generated natural gas are relatively small.