黏声介质逆时偏移相速度校正方法  

Phase velocity correction for viscoacoustic reverse time migration

作　　者：许璐 刘国峰[1] 李博 王小青 徐强 XU Lu;LIU Guofeng;LI Bo;WANG Xiaoqing;XU Qiang(School of Geophysics and Information Technology,China University of Geosciences(Beijing),Beijing 100083,China;SINOPEC Geophysical Research Institute Co.,Ltd.,Nanjing,Jiangsu 211103,China)

机构地区：[1]中国地质大学(北京)地球物理与信息技术学院,北京100083 [2]中石化石油物探技术研究院有限公司,江苏南京211103

出　　处：《石油地球物理勘探》2025年第1期119-126,共8页Oil Geophysical Prospecting

基　　金：国家重点研发计划项目(2022YFC2807403);中石化科技部项目“波动方程全方位高精度成像技术研究”(P23010)联合资助。

摘　　要：地震波在黏声介质中传播时会引起振幅衰减与相位频散,影响成像剖面的分辨率与成像精度。考虑黏声介质吸收衰减补偿作用的逆时偏移成像方法(QRTM)是改善沙漠地表以及气囱等强衰减区域成像精度与分辨率的有效方法之一。基于广义标准线性体的黏声波动方程可实现数值的高效求解,但相速度与理论解的不一致会造成构造成像位置的变化,降低成像聚焦性与成像精度。为此,提出了一种黏声介质逆时偏移成像相速度校正方法。在方程中引入校正系数并通过反演进行求解,基于求解的校正系数实现对相速度的校正,从而保持相速度频散关系不变的条件下实现振幅衰减补偿,使成像得到正确归位,提高成像精度。理论模型与实际数据测试结果表明,基于黏声介质逆时偏移相速度校正成像方法可以补偿振幅衰减与校正相位频散,该方法适用于超深层勘探中消除吸收衰减作用对中深层成像的影响,提高剖面质量。The propagation of seismic waves in viscoacoustic media induces the attenuation of amplitude and phase dispersion,thereby influencing the resolution and accuracy of seismic imaging profiles.The Q‑compensated reverse time migration method(QRTM)considering the compensation effect of attenuation in viscous acoustic media is an effective approach to improve the imaging accuracy and resolution in strongly attenuative areas,such as desert surfaces and chimneys.Efficient numerical solutions are achieved based on the viscoacoustic wave equation solution algorithm of the generalized standard linear solid model.However,a discrepancy between the phase velocity and the theoretical solution leads to position shifts in the structural imaging,compromising the imaging focus and accuracy.To address this issue,this paper proposes a method to correct the phase velocity in QRTM.This method introduces an optimization term into the equation and constructs an inversion solution of the correction coefficient to solve the objective function.Based on the solved correction coefficient,the phase velocity is corrected,thereby the attenuation compensation of amplitude is realized under the condition of maintaining the dispersion relationship of the phase velocity unchanged.This ensures accurate positio‑ning of the imaging results and enhances imaging accuracy.The results of the theoretical model and actual data tests demonstrate that using the QRTM to correct phase velocity can compensate for the attenuation of amplitude and correct phase dispersion.This method is suitable for eliminating the impact of the attenuation effect on mid‑deep imaging during ultra‑deep exploration,thus improving the profile quality.

关 键 词：黏声介质 逆时偏移 振幅衰减 相位频散 优化策略 

分 类 号：P631[天文地球—地质矿产勘探]