塔河油田南部中奥陶统一间房组沉积相精细划分

Sedimentary facies division of Yijianfang Formation in the middle Ordovician of the southern Tahe Oilfield

从地质、测井及地震等方面,阐明了一间房组层序关键界面识别与划分的标志,利用层序地层学方法对一间房组与上覆恰尔巴克组的地层分界进行了重新厘定,在三级层序框架内建立了一间房组上部的五级层序高精度地层格架,并结合钻井及地震资料恢复了三级层序沉积相。在此基础上,对一间房组上部Ⅱ—Ⅴ高频层序的滩体进行了精细刻划,分析了各个高频层序滩体演变规律。塔里木盆地在中奥陶世已由早奥陶世的一个台地分化成了2个台地。一间房组发育开阔台地相和台内礁滩相两种沉积相,礁滩体发育于台内坡折带内缘,为台内点礁和小型滩。

The signs for recognizing and dividing the key sequence interface in Yijianfang Formation were analyzed by using geology, log and seismic methods. The boundary between Yijianfang Formation and Qiaerbakezu Formation was newly conformed according to the sequence stratigraphy. The high-revolution sequence stratigraphy framework for fifth-order sequence in the upper Yijianfang Formation （the upper high system tract）was founded within the three order sequence. The three-order sedimentary facies were resumed using well drilling and seismic data. The beach body distribution in Ⅱ-Ⅴ high frequency sequence in the upper Yijianfang Formation was finely depicted, and the beach body evolvement law in each high frequency sequence was analyzed. It shows that one platform was divided into two platforms from early Ordovician to the middle Ordovician in Tarim Basin. Two sedimentary facies including open platform, intraplatform reef and beach body facies were developed in Yijianfang Formation, and the reefs and beach body characterized by point reefs and beach body within the carbonate platform were distributed in the break of slope of the platform.