三维多波地震双反演储层预测技术在苏里格气田的应用

三维多波地震双反演储层预测技术基于AVO原理,其输入数据是PP波和PS波的角度道集(或者叠加数据),反演结果综合了时间域和振幅域的信息。通过在反演过程中使用一个初始模型约束反演,使结果吻合低频初始纵、横波速度比的趋势。具体步骤如下:①选择目的层反演层段进行PP/PS层位匹配,求出目的层段纵、横波速度比,并将PS波数据压缩至PP波时间域;②通过一系列的模拟退火运算以及参数控制,让约束条件方程不断收敛,不断逼近一个最小值,直至得到一个全局最优反演的纵、横波速度比;③利用得到的纵、横波速度比,进一步反演得到纵、横波速度和密度;④最终由纵、横波速度和密度信息计算出泊松比、拉梅系数和流体因子等弹性参数。本文通过对鄂尔多斯苏里格气田多波三维地震转换波静校正、波场分离、速度分析、振幅恢复等处理技术进行深入研究,得到了品质较高的地震多分量资料,在此基础上,利用双反演方法进行纵、横波联合解释,细化了储层的非均质性,找出了相对含气富集区。

Dual-inversion reservoir prediction of 3D multi-wave seismic data in Sulige Gas Field

Dual-inversion reservoir prediction of 3D multi-wave seismic data is based on AVO principle.Its inputs are PP wave and PS wave angle gathers(or post-stack data).Inversion syntheses time domain and amplitude domain information.Using an initial model constrained inversion the results are consistent with low frequency initial VP/VS trend.Specific steps are as follows: ①Matching VPP/VPS horizons in interest layers;finding out its VP/VS;and compressing VPS data into PP time domain.②By simulated annealing and varying parameters constraint equations continuously converges to minimum while global optimal VP/VS is obtained.③Using further inversion of the VP/VS,VP,VSand density are obtained.④Finally poisson’s ratio,Lame coefficient and elastic parameters such as fluid factor are calculated.After converted wave static correction,wave field separation,velocity analysis,and amplitude recovery,this dual-inversion gets better quality seismic multi-component data in Sulige Gas Field.The results show clearer reservoir heterogeneity in target layers and identify gas-rich beds.