基于叠前AVAZ反演的火山岩裂缝预测方法研究

Study on volcanic rock fracture prediction method based on prestack AVAZ inversion

火山岩裂缝是储层预测的关键要素,目前火山岩裂缝预测主要基于叠后或分方位叠加数据,预测精度较低。将基于全方位OVT域道集的叠前AVAZ反演方法引入到火山岩储层的裂缝预测中,以松辽盆地某火山岩储层为研究区开展方法的实际应用。首先分析了研究区OVT道集的方位各向异性;然后利用HTI介质的Ruger方程开展叠前AVAZ反演,得到了裂缝发育密度和裂缝方位数据体,实现了火山岩裂缝定量预测;最后通过研究区断裂分布和成像测井规律验证了该方法的准确性和可靠性,相比于其他方法提高了裂缝预测精度,为火山岩气藏的裂缝识别提供了一种高精度预测方法。

Volcanic rock fracture is the key element of reservoir prediction.At present,volcanic rock fracture prediction is mainly based on post-stack or azimuthal stacking data,with low prediction accuracy.Therefore,this paper introduces the prestack AVAZ inversion method based on omni-directional OVT domain gathers into the fracture prediction of volcanic reservoir,and takes a volcanic reservoir in Songliao Basin as the research area to carry out the practical application of the method.Firstly,the azimuthal anisotropy of OVT gathers in the study area is analyzed;Then use the Ruger equation of HTI medium to carry out prestack AVAZ inversion,obtain the fracture development density and fracture orientation data volume,and realize the quantitative prediction of volcanic rock fractures;Finally,the accuracy and reliability of the method are verified by the fracture distribution and imaging logging law in the study area.Compared with other methods,this method improves the accuracy of fracture prediction and provides a high-precision prediction method for the fracture identification of volcanic gas reservoirs.