摘要
鄂尔多斯盆地石炭系海相烃源岩与下奥陶统碳酸盐岩的对比结果表明，石炭系海相烃源岩虽然不如下奥陶统碳酸盐岩厚，但其生烃能力远高于后者，与奥陶系风化壳储集层的配置情况也好于后者，并且产物也具油型特征，表明奥陶系风化壳气藏的油型气成分来自石炭系海相烃源岩；奥陶系风化壳气藏的天然气是以上古生界煤成气为主、上古生界石炭系油型气为辅的混合气。这一观点既能够很好地解释鄂尔多斯盆地中部古生界自上而下气藏序列天然气成分及碳同位素组成的差异，还可以更好地说明为何风化壳气藏天然气以煤成气为主。
Natural gas produced from the weathered crust at the top of Lower Ordovician in Changqing gas field in the Ordos basin has some characteristics of oil type gas (e.g. δ 13C 2<-29‰). Its main source rock has been in dispute since its discovery with one side holding the Lower Ordovician marine carbonate platform while the other holding Upper Paleozoic coal seam above the unconformity. But both sides omitted the contribution of Carboniferous marine source rock (including mudstone and limestone). In this article, the Carboniferous marine source rocks is found to be better than Ordovician one in three points: hydrocarbon potential, organic facies, sealing rock between source rock and reservoir. Hydrocarbon from Carboniferous marine source rock is also of oil type. So oil typed gas in Ordovician weathering crust was derived mainly from Carboniferous marine source rock. This conclusion can well illustrate the following: ①coal type gas is main components in this gas reservoir; ②there is certain variance in gas reservoirs from top to bottom of Paleozoic strata in the Ordos basin.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
1999年第4期22-24,共3页
Petroleum Exploration and Development
关键词
气田
奥陶系
风化壳气藏
油型气
成分
Eerduosi basin, Changqing gas field, Weathering crust, Gas reservoir, Coal formed gas, Oil formed gas, Gas source rock
