CAJ | 학술논문

成像条件是决定声波方程叠前逆时深度偏移效果的重要因素。常规的归一化互相关成像条件能补偿深部地层的反射波能量，但无法压制地震波逆时偏移过程中产生的偏移噪声。针对归一化互相关成像条件的主要缺陷，从二维声波方程出发，在交错网格空间中推导了声波方程逆时延拓的高阶有限差分格式和PML吸收边界条件，进而在对常规互相关成像条件分析的基础上对其进行改进，给出了一种加权互相关成像条件，即在成像过程中利用炮检波场的夹角进行加权校正，以实现只利用炮点下行波场与接收点上行波场进行成像的目标。模型数据和实测资料偏移结果表明，归一化加权互相关成像条件成像效果明显优于常规归一化互相关成像条件。
성상조건시결정성파방정첩전역시심도편이효과적중요인소。상규적귀일화호상관성상조건능보상심부지층적반사파능량，단무법압제지진파역시편이과정중산생적편이조성。침대귀일화호상관성상조건적주요결함，종이유성파방정출발，재교착망격공간중추도료성파방정역시연탁적고계유한차분격식화PML흡수변계조건，진이재대상규호상관성상조건분석적기출상대기진행개진，급출료일충가권호상관성상조건，즉재성상과정중이용포검파장적협각진행가권교정，이실현지이용포점하행파장여접수점상행파장진행성상적목표。모형수거화실측자료편이결과표명，귀일화가권호상관성상조건성상효과명현우우상규귀일화호상관성상조건。
The imaging condition is an important factor to determine acoustic wave equation prestack reverse time depth migration effec-tiveness. The conventional normalized mutual correlation imaging condition can compensate deep strata reflected energy, but can not suppress noises from seismic wave reverse time migration. In allusion to main defect in normalized mutual correlation imaging condi-tion, starting from 2D acoustic wave equation, deduced the equation’s reverse time extrapolation high order finite difference scheme and PML absorbing side boundary condition in staggered grid, then carried out improving based on conventional mutual correlation im-aging condition analysis. A kind of weighted mutual correlation imaging condition puts out, that is using shot-detector wave fields in-cluded angle to carry out weighted correction, realize imaging use only shot point downward wave field and receiver site upward wave field. The model data and measured data migration has shown that the normalized weighted mutual correlation imaging condition is ob-viously superior to conventional normalized mutual correlation imaging condition.