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地球化学特征显示,松辽盆地在多处发现的高含量CO2气藏属于无机成因天然气,徐家围子地区发现的具重碳同位素和负碳同位素系列的烃类气体说明盆地不内不仅存在无机成因的CO2气藏,而且也极有可能形成无机成因的烃类气藏。盆地深部地质研究表明,地幔上隆、地壳减薄、地壳中发育的“网状”结构以及部分深大断裂的发育,使松辽盆地具备了形成无机成因气的条件,也说明盆地内现在发现的无机成因天然气可能来源于地球深部。 地球内部不同圈层内发育的流体是无机成因天然气 形成的基础。松辽盆地古中央隆起带两侧、西部凹陷区是无机成因天然气发育的有利地区;沿嫩江大断裂带和幔源岩浆底劈带是寻找无机烃类气体的有利地区。

Abiogenetic Natural Gases in Songliao Basin and Their Exploration Prospects

It is shown by geochemical characteristics that the natural gas rese rvoirs containing a great number of carbon dioxide,which were found in Songliao Basin everywhere,belong in abiogenetic ones,and the hydrocarbon gas,found at Xuj iaweizi region and being of heavy carbon isotope and reverse carbon isotopic ser ies,indicates that in the basin there are not only abiogenetic carbon dioxide ga s reservoirs but the abiogenetic hydrocarbon gas reservoirs probably exist. The research results of deep basin geology reveal that Songliao Basin possesses the conditions of forming abiogenetic gases because of mantle arching,crustal at tenuation and developed "net"structure and discordogenic faults in the crust,a nd that the abiogenetic natural gases found in the basin may be originated from the deep part of the earth.The fluids developed in various spheres and layers in the earth interior are the foundation of forming abiogenetic natural gases.In S ongliao Basin,both sides of the ancient central uplift belt and the western depression are the favourable areas of forming abiogenetic natural gases and the discordogenic fault belt along Nenjiang River and mantle source magma diapirism belt are the beneficial areas of prospecting for abiogenetic hydrocarbon gases.