叠前AVA多参数同步反演技术在含气储层预测中的应用

Application of prestack simultaneous AVA multi-parameter Inversion in gas-bearing reservoir prediction

随着油气勘探的不断深入,叠前地震数据的反演和应用逐渐成为热点。叠前AVA同步反演可从小、中、大三个角度部分叠加数据体上同步反演出纵、横波阻抗和密度数据体。在此基础上,可提取出地层的组合弹性参数。通常砂岩储层含气后纵波速度明显降低,横波速度变化不大,同时密度也降低。与单纯应用纵波阻抗相比,纵、横渡阻抗等属性联合可提高流体的识别精度。因而,应用同步反演技术进行含气储层识别是可行的。首先介绍了叠前AVA同步反演的基本原理,继而从地震和测井资料处理、角度子波提取和标定以及最终反演等方面,讨论了叠前AVA同步反演技术在胜利油田中层气藏勘探中的应用。结果表明该方法进行含气储层预测是有效的。

With the development of oil & gas exploration,inversion and application of prestack seismic data is becoming the focus.Prestack simultaneous AVA inversion can simultaneously inverse P-wave and S-wave impedance and density data volume from small/middle/ far angle stacked data volume.Based on the inversion result,the combined elastic parameters can be obtained.Being filled with gas, the compressional velocity of sandstone will usually decrease,the shear velocity does not change much,and the density decrease.If only the acoustic impedance is used,the combination of attributes of P-wave and S-wave impedance can improve the discriminating ac- curacy of fluid.So it is feasible to discriminate gas-bearing reser- voir by using prestack simultaneous inversion technique.The basic principle of simultaneous inversion is introduced firstly and then the application of prestack simultaneous AVA inversion in exploration of middle-depth gas reservoir at Shengli oil field is discussed in some aspects,such as seismic data and well logs processing,angle wavelet extracting and calibrating,and inversion.The result shows that the method is effective in gas-bearing reservoir predic- tion.