塔里木盆地顺托果勒低隆起一间房组分布及地质意义

Distribution and significance of Middle Ordovician Yijianfang Formation in Shuntuoguole lower uplift,Tarim Basin

在塔里木盆地顺托果勒低隆起相关钻井中获得了中奥陶世达瑞威尔期牙形石化石,由老到新分别为Eoplacognathus suecicus、Pygodus anitae和Pygodus serrus组合,为该区主要目的层之一的一间房组划分对比提供了较为详细的标准生物化石依据。同时,综合碳同位素地层、岩电特征和地震等资料,讨论了一间房组地层发育特征。在此基础上,通过连井地层划分对比和地震层位解释追踪,厘定了一间房组的分布范围。研究认为,一间房组在顺托果勒低隆起广泛分布,厚度为140~220 m,SN1-ST1井区厚度最大,超过了200 m。研究区一间房组—恰尔巴克组之间为连续沉积,不存在剥蚀不整合面,不具备发育加里东中期古喀斯特的地质条件。

The Middle Ordovician Darriwilian stage conodonts have been recovered from key wells in theShuntuoguole lower uplift, Tarim Basin. They are Eoplacognathus suecicus, Pygodus anitae and Pygodus serrus inascending order. These fossil provide the basis for the division and correlation of the Yijianfang Formation which is oneof the main exploration targets. The characteristics of the Yijianfang Formation were analyzed based on isotopic strati-graphy, lithologic and petrophysical features and seismic data at the same time. On this basis, the distribution of theYijianfang Formation in this district was analyzed through the comparison of the stratigraphic division, precise trackingand interpretation of seismic horizons. This formation is widely distributed in the Shuntuoguole lower uplift, with athickness of 140-220 m. It has the largest thickness （〉 200 m） in the SN1 to ST1 well area. There is no erosionunconformity between the Yijianfang Formation and the Qiaerbake Formation, which did not allow the development ofpaleo karst in the Middle Caledonian.