基于局部平面波分解的逆时偏移角道集提取方法

A method for extracting angle-domain common-image gathers based on local plane wave decomposition

高精度地震勘探的普及和GPU技术的发展,使叠前逆时偏移技术得到日渐广泛的实际应用。逆时偏移方法成像精度高,对复杂地质构造成像效果好,且不受地层倾角限制。角度域共成像点道集作为逆时偏移的重要输出,可为速度分析、AVA分析提供速度、振幅等信息。本文提出一种逆时偏移角道集提取方法,采取局部平面波分解法将震源波场和检波点波场分解为局部角度分量,再利用角度域互相关成像条件输出角道集。该方法对复杂构造的适应性较好,尤其适用于在逆时偏移中提取角道集。通过模型试算和实际资料测试,验证了方法的可行性和有效性。

With the development of high precision seismic exploration and GPU technology,the prestack reverse-time migration(RTM)becomes a routine nowadays.The reverse-time migration shows great superiority in dealing with complex velocity models without limits of tilt angle.As an important output of reverse-time migration,the angle-domain common-image gather(ADCIG)can provide velocity information and amplitude information for velocity analysis and analysis of amplitude variation with angle of incidence(AVA).In this paper,we propose a method for extracting angle-domain common-image gathers from reverse-time migration.First the source wavefield and receiver wavefield are decomposed into local angle-domain components,and then angle-domain cross-correlation imaging conditions are used to angle-domain commonimage gathers.The proposed method has good adaptability to complex structures.Finally,model and field data tests prove the effectiveness and feasibility of the proposed method.