松辽盆地天然气成因探讨  

Controversy of the Origins of Natural Gas in Songliao Basin

作　　者：魏志平[1] 张景廉[2] 方乐华[2] 杜玉潭[2] 

机构地区：[1]中国石油大学(北京)资源与信息学院,北京102249 [2]中国石油勘探开发研究院西北分院,兰州730020

出　　处：《新疆石油地质》2009年第4期537-542,共6页Xinjiang Petroleum Geology

摘　　要：松辽盆地徐家围子断陷的天然气成因备受争议,焦点是有机成因气还是无机成因气。费托合成烃的反应可以发生如光合作用那样的碳同位素分馏作用,但未必显示碳同位素的反序分布。热液条件下费托反应在自然界更普遍,但其碳氢同位素的动力学分馏特征尚不十分清楚,碳同位素组成用于油气物源示踪识别仍有很大的不确定性。松辽盆地深部地壳特征表明,中地壳有一低速高导层,地幔流体CO2、H2可在此进行费托合成烃的反应,这种超临界的流体的反应可形成烃和烃类化合物。根据这一思路,松辽盆地深部(不仅仅是火山岩,还有花岗岩等基底岩石)有更多的天然气尚待勘探与发现,也可在其他盆地寻找大油气田。The origin of natural gas of Xujiaweizi fault depression in Songliao basin is heavily debatable on that account whether it is biogenetic or abiogenetic. There are different interpretations on the origins of natural gas in the nature. The carbon isotopic fractionation can be taken place in Fischer-Tropsch synthesis just like in plants＇ photosynthesis possibly without indication of reverse distribution of carbon isotope. Fischer-Tropsch reaction under the hydrothermal conditions is very common in the nature, but the kinetic fractionation mechanism of carbon and hydrogen isotopes is not clear. Carbon isotope used for the trace distinguishing of oil-gas sources is still of great uncertainty. The deep crust structures of Songliao basin show that there exists a low velocity-high conductive layer in the mid-crust, in which the mantle fluids enriched with CO2, H2 could take part in reactions of Fischer-Tropsch synthesis and generate hydrocarbon compounds. Based on this thought, much more natural gases could be explored and discovered in deep Songliao basin （including volcanic rocks, granites and other basement rocks）. In addition, giant oil-gas fields could be found out in other domestic basins by such a thought.

关 键 词：松辽盆地 天然气 无机成因 费托合成反应 碳同位素 中地壳 低速高导层 地幔流体 

分 类 号：TE112.11[石油与天然气工程—油气勘探]