密井网条件下随机地震反演及其在河道砂体预测中的应用

以大庆长垣油田萨尔图油层为例，研究了密井网条件下随机地震反演方法及其在河道砂体预测中的应用。研究表明：不同厚度砂体的随机地震反演结果符合率差异较大：厚度大于3m的砂体符合率为91%；厚度为2～3m的砂体符合率为83%；厚度小于1m的砂体符合率为70%。随着砂体厚度的减小，符合率降低，井网密度越大，预测精度下降幅度越小。利用“地震反演引导，井点微相控制”方法，根据测井曲线形态差异与反演剖面砂体发育状况的分析，能够较为准确地对河道砂体的单一河道边界、走向、井间砂体叠置关系及窄小河道砂体进行描述。利用随机地震反演结果在河道砂体沉积模式的控制下完成油田开发中后期各类河道砂体的精细描述是切实可行的，且效果显著。

Stochastic seismic inversion and channel sandbody prediction in dense well pattern areas

We propose an approaoch for channel sandbody prediction based on stochastic seismic inversion in dense well pattern area and apply it in Saertu reservoir, Daqing Oilfield. From this study, it is found that stochastic seismic inversion results are different with different sandbody thickness. The coincidence rate of inversion results is 91% when sandbody thickness more than 3m. When sandbody thickness is 2 to 3m, the coincidence rate is 83%. This rate is 70% when sandbody thickness become less than 1m. The prediction accuracy declines with sandbody thickness and well pattern density decreases. Using seismic inversion, well microfacies control, and logging curves, cross-well sandbody, narrow channel sandbody, and channel boundaries and directions can be accurately characterized. Our application demonstrates that the propsed appoach is feasible and effective with channel sandbody sedimentary model for channel sandbody prediction in later oilfield development stages.