准噶尔盆地天然气地质条件、资源潜力及勘探方向

Geological conditions,resource potential and exploration direction of natural gas in Junggar Basin

准噶尔盆地是西部大型叠合含油气盆地,油气资源丰富,但油气发现程度差别较大。从已发现的天然气藏分布入手,分析成藏条件,总结成藏模式,预测有利的天然气勘探领域与区带,指导盆地天然气勘探。分析认为,盆地主要发育石炭系、二叠系(佳木河组)、侏罗系3套气源岩,从石炭系至古近系发育5套天然气储盖组合。气藏具有独立、近源成藏特点,盆地天然气成藏主要有2种模式:源内—自生自储—不整合面—断裂原生成藏模式,以陆东—五彩湾石炭系为代表,是盆地主要成藏模式;近源—下生上储—挤压背斜带—断裂次生成藏模式,以南缘山前古近系为代表。有利勘探领域主要有:陆东—五彩湾(以石炭系为主)、南缘山前冲断带(侏罗系—古近系)、中拐凸起带(以二叠系为主)以及盆地深层(以石炭系、二叠系为主)。加大这些领域天然气勘探是实现该盆地油气并举的重要保障。

Junggar Basin is a large superimposed petroliferous basin in the western and has abundant oil and gas resources.However,there is an obvious difference between the degree of petroleum and natural gas ex-ploration.The paper attempts to analyze hydrocarbon accumulation, summarize accumulation model and predict favorable exploration fields and blocks for natural gas, to guide basin natural gas exploration on the basis of discovered gas reservoirs.The analysis suggests,there are three sets of source rocks（Carboniferous Permian Jurassic） ,five sets of natural gas reservoir cap assemblages from Carboniferous to Paleogene.The gas reservoir is characterized by independent, near-source accumulation.There are 2 main formation models for natural gas in the basin. In-source-self-generation and self-preservation-unconformity-fault source-gen- erated reservoir,represented by the Carboniferous from Ludong to Wucaiwan,which is the main accumula- tion model-near source-lower-generationand upper-accumulation-crushing anticline-fault secondary reser voir model,represented by the Paleogene in front of Nanyuan mountain. The favorable exploration fields mainly include. Ludong-Wucaiwan（Carboniferous）,thrust belt in the south edge of the mountain front （Ju- rassic-Eocene of Paleogene） ,Zhongguai raised belt （mainly Permian） and deep basin（mainly Carboniferous and Permian）.Increasing exploration in the fields is the important supporting measure to realize simultane- ous development of oil and gas.