辫状河储层内部构型研究与应用

大港油田采油一厂以河道砂岩控制的地质储量占总储量的85%,分布在明化镇和馆陶油组,目前已进入特高含水期,层间层内矛盾突出。其中馆陶油组主力开发油层普遍较厚,单砂体厚度可达15~30m,内部存在隔夹层,虽然经过长期高速开采,厚油层内仍然存在未动用或含油饱和度较高的部位,油层内部存在25~35%未采出的可动油,这些剩余油的存在大部分是由于对储层的非均质性认识不足造成的。本文在港东一区六断块馆陶油组综合应用多学科资料对辨状河河道砂体的内部构型进行研究,识别厚油层内部隔夹层展布特征,探索应用井-震结合进行辨状河储层内部构型研究的思路和方法,提高油层动用程度。

A Study on the Internal Architecture of Braided Fluvial Reservoir and Application

85percent of proved oil reserves of the First Oil Production Plant of Dagang Oilfield is preserved in the channel sand of Guantao and Minghuazhen formation of Neogene.After 40years of water injection exploiting,the plant is in a stage of extra-high water cut now,in which both conflicts in and between layers are particularly obvious.The major exploiting layers in Guantao formation are naturally thick in common.The thickness of single sand body reaches up to 15to 30meters,where complicated interlayers lay in due to braided river sedimentary environment.Although the plant keeps a high level of production and in the stage of extra-high water cut now,there is appreciably 25to 35percent of remaining oil reserves,which is undeveloped or remaining high-saturated in developed areas under the control of reservoir heterogeneity due to our inadequate cognition.This paper shows the process of braided fluvial reservoir internal architecture by linking well-log and seismic together in a fault block of Gangdong oil deposit.We try to reveal the features of interlayers in Guantao formation by the aid of multidisciplinary analysis including river sedimentation model,outcrop and modern deposition studies,sedimentology and seismogeology etc.,in order to find a generic and efficient way in reservoir internal architecture as well as in improving the producing degree.