松辽盆地庆深气田储层火山岩锆石U-Pb同位素年龄及其地质意义

庆深气田储层火山岩是由多期火山喷发叠置形成,分布在白垩系下统的营城组,以酸性喷发岩为主。火山岩离子探针(SHRIMP)锆石U-Pb年龄测定结果表明,储层火山岩年代集中在111~115 Ma,介于早白垩世晚期阿普第阶(Aptian)和阿尔布阶(Albian)的分界线附近。对比兴城与升平两个天然气产区的储层火山岩的形成年代,发现它们是同一时代的火山作用产物,并不是以前所认为的兴城地区火山岩属于营城组一段,升平地区火山岩属于营城组三段。这一结果对于松辽盆地火山岩气藏的勘探开发具有实际意义。

SHRIMP Zircon U-Pb Age and Geological Meaning of Reservoir Volcanic Rocks in Qingshen Gas Field of the Songliao Basin, NE China

The reservoir volcanic rocks of the early Cretaceous Yingcheng Formation in Qingshen gas fields of the Songliao Basin are mainly rhyolites that have been selected for zircon U-Pb dating from the two major gas-producing regions called Xingcheng and Shengping.SHRIMP ages of the reservoir volcanic rocks range from 111 Ma to 115Ma,being the Mid-Cretaceous Aptian to Albian stage.Results of the volcanic eruption ages of the two regions suggest that all the reservoir volcanics are cotemporary and formed at the same period of volcanism,which is different from previously understanding about them.Traditionally the volcanic rocks used to be thought different ages,the volcanic reservoir rocks of Shengping were believed to be younger(K1yc3) than those from Xingcheng(K1yc1), which should be modified according to our results.The result is very significant to exploring and exploiting volcanic gas pool of the northern Songliao Basin.