利用高分辨率波阻抗反演技术预测薄储层——以辽河坳陷牛居地区为例

Thin bed prediction with high-resolution impedance inversion: a case study of Niuju Area,Liaohe Basin

牛居地区位于辽河坳陷东部凹陷北段,储层为薄互层砂岩,单层厚度大多小于5m。受地震分辨率限制,常规波阻抗反演难以识别薄砂层。为此,开展高分辨率波阻抗反演。首先根据牛居地区储层特点开展正演模拟分析,为薄储层定性及定量预测提供依据;其次通过多属性对比分析,筛选出最大波谷振幅属性定性预测砂体展布特征;再基于GeoEast软件反演模块,开展高分辨率波阻抗反演;最后,采用门槛值法分层段提取砂岩含量和砂岩厚度,定量预测砂岩发育区。砂岩厚度预测吻合率达78.6%,能较好地预测研究区砂体展布情况,为勘探部署提供了有利依据。

Niuju Area is located in the north of the East Depression,Liaohe Basin,thin inter-bedded sands and shales are main sedimentary characteristics of reservoirs,and the thickness of a single bed is mostly less than 5 meters.Therefore,high-resolution impedance inversion is needed.Firstly,we carry out qualitative and quantitative prediction of thin beds based on reservoir calibration and forward modeling.Then,with multi-attribute comparison we select maximum trough amplitude attributethat can effectively show the distribution characteristics of sand bodies.Afterwards,reservoirs are predicted with the high-resolution impedance inversion provided by GeoEast.Finally,the sand thickness prediction is achieved with the threshold value method.Our prediction has a coincidence rate of 78.6%,which is very helpful for the improvement of exploration drilling success rate.