1. Science and Technology Research and Development Center,Sinopec Petroleum Engineering Geophysical Limited Corporation,Nanjing 211100,China 2. Shengli Branch Company,Sinopec Petroleum Engineering Geophysical Limited Corporation,Dongying 257100,China 3. School of Geosciences,China University of Petroleum (East China),Qingdao 266580,China
Poor illumination poses great challenges to the imaging of small-scale faults and pores.Subsurface attenuation leads to amplitude loss and phase distortion of seismic waves,and ignoring such attenuation during imaging will blur migration amplitudes.The Q-compensated least-squares reverse time migration (QLSRTM) can improve the imaging of these small-scale structures,but it requires a huge amount of iterations and computational cost.To improve the imaging effect of these small-scale structures,this study proposed a geological-target-oriented joint QLSRTM (J-QLSRTM) that fully utilizes diffracted waves.In this method,a new objective function and gradient formula was constructed.Moreover,the Q-compensated wavefield propagation operators,Q-compensated adjoint operators,and Q-attenuated demigration operators were derived for both primary and diffracted waves based on the inversion and adjoint theories.The numerical examples verified that the proposed J-QLSRTM is superior to the conventional QLSRTM and the acoustic J-LSRTM.
Lei-Liang XU,Guo-Yong ZHAO,Jian ZHANG, et al. Joint Q-compensated least-squares reverse time migration using primary and diffracted waves[J]. Geophysical and Geochemical Exploration,
2023, 47(1): 91-98.
Three layer attenuation model with small-scale caves
The shot records from the viscoelastic medium(a), acoustic medium(b),and the shot records of diffracted waves separated from the attenuating shot records(c) and separated reflected waves by cutting off the direct wave(d)
Wave field compensation test with 600 ms
The attenuating Sigsbee2B velocity model(a)and Q model(b)
J-QLSRTM imaging results obtained by using the velocity field in Fig.10a(a) and by using the Q field in Fig.10b(b)
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