双复杂条件下弹性波非倾斜叠加精确束偏移方法研究

目前，随着勘探开发逐渐转向地表和地下双复杂区域，非分离多波多分量数据的偏移成像成为地震数据处理的一个难题。为此，基于前人的研究成果，发展了一种双复杂条件下的弹性波非倾斜叠加精确束偏移方法。首先，基于地表倾角信息和非倾斜叠加地震数据，直接在接收点处出射弹性动力学高斯束并计算解耦的反向延拓矢量波场;其次，根据互相关成像条件以及纵、横波的偏振特性，进行P波和转换S波高斯束偏移成像，并对转换S波成像进行极性校正。典型双复杂构造模型的偏移试算和角道集提取分析结果以及与常规方法成像结果的对比表明，弹性波精确高斯束偏移方法消除了常规方法由于束中心位置与接收点位置之间距离较大所致的振幅误差，验证了弹性波非倾斜叠加精确束偏移方法的正确性和有效性。

 Today,since the development trend of exploration and exploitation is gradually transferring to dual-complexity areas,the imaging based on unseparated multi-wave multi-component dataset has become a conundrum in the data processing.Based on surface dip-angle information and seismic data without slant stack,elastic dynamic Gaussian beams are emitted directly on complex surface and then decoupled backward-continued vector wavefield can be calculated.According to the cross-correlation imaging condition and polarization features of vector wavefield,PP and converted PS imaging are implemented.Finally,polarity reversal in converted PS imaging is corrected.Compared to the conventional elastic Gaussian beam migration for irregular surface,our method doesn’t have the following modules:①elevation statics;②phase correction;③approximate substitution of speed and take-off angle between receivers and the beam centers.Our method is tested by using the unseparated multi-wave multicomponent data from a representative dual-complexity model and extract angle-domain common image gathers (ADCIGS).The result shows that compared with conventional method,our method can effectively eliminate the imaging energy error caused by the large distance between the beam center and detectors.Examples show the accuracy and efficiency of our method.