扩展弹性阻抗反演在东海T气田储层预测中的应用  

Application of extended elastic impedance inversion in reservoir prediction of T gas field in the East China Sea

作　　者：胡伟 孙永壮 张岩 尹文笋 刘庆文 HU Wei;SUN Yongzhuang;ZHANG Yan;YIN Wensun;LIU Qingwen(Shanghai Branch of CNOOC Co.Ltd.,Shanghai 200335,China)

机构地区：[1]中海石油(中国)有限公司上海分公司,上海200335

出　　处：《上海国土资源》2021年第4期73-78,共6页Shanghai Land & Resources

基　　金：“十三五”国家科技重大专项“东海深层低渗—致密天然气勘探开发技术”(2016ZX05027001)。

摘　　要：扩展弹性阻抗反演是常规叠后声阻抗反演的一种深化,是一项融合了叠后声阻抗反演和叠前AVO反演的技术,其既具备叠后地震的高信噪比特征,又利用了能反映岩性和含油气性的叠前AVO信息。本文阐述了该方法的基本原理和实施的关键步骤,并给出进行储层预测的应用实例。东海T气田HG组砂、泥岩地震响应差异小,纵波阻抗不能有效刻画储层,为此开展了扩展弹性阻抗反演研究。利用测井曲线纵波速度、横波速度、密度结合岩性敏感参数进行分析,求取最优岩性角度下的扩展弹性阻抗曲线,其能够较好地区分砂、泥岩。再结合叠前地震道集反演得到扩展弹性阻抗体,预测岩性与实钻井吻合较好,并且刻画的砂体平面展布特征符合地质认识,为气田区的滚动勘探开发提供了有力支持。Extended elastic impedance inversion is a deepening of the conventional post-stack acoustic impedance inversion.This technology combines post-stack acoustic impedance inversion and pre-stack AVO inversion.It not only has the characteristics of a high signal-to-noise ratio of post-stack seismic data but also uses prestack AVO information that can reflect lithology and oil-gas potential.This article introduces the basic principles and key steps of this method and provides an application example of reservoir prediction.The seismic response difference of sandstone and mudstone in the Hg formation of the T gas field in the East China Sea is small,and the P-wave impedance cannot effectively describe the reservoir.Therefore,extended elastic impedance inversion was carried out.By analyzing the P-wave velocity,S-wave velocity,and density of the logging curve combined with lithology-sensitive parameters,the extended elastic impedance curve under the optimal lithology angle is obtained,which can better distinguish sand and mudstone.The extended elastic impedance was obtained by inversion with prestack seismic data,and the predicted lithology was in good agreement with actual drilling.In addition,the characteristics of the planar distribution of the sand body are in line with the geological understanding and provide strong support for the rolling exploration and development of the gas field area.

关 键 词：油气勘探开发 地球物理勘探技术 地震反演技术 扩展弹性阻抗 声波阻抗 梯度阻抗 岩性角 储层预测 

分 类 号：P631.4[天文地球—地质矿产勘探]