Frequency-space Domain Viscoacoustic Wave Equation Forward Simulation And Reverse Time Migration

Conventional theory is based on elasticity of underground medium and seismic wave does not suffer from any attenuation effect during propagation,which,however,does not stand in practice.Attenuation effect leading to reduction of energy and narrowing of frequency band occurs during propagation of seismic wave.Therefore,with the development of oil industry,conventional seismic wave forward simulation & migration techniques are no longer able to meet the recent requirement of seismic prospecting in regards to resolution.In order to solve the problem of resolution reduction due to attenuation effect,viscoacoustic forward simulation & migration is becoming a hot spot in recent studies.On the one hand,frequency-space domain forward simulation is free from the error accumulated with time.Also,under the assumption of viscosity,velocity is the function of frequency.By introducing complex velocity model,frequency-space domain forward simulation can simulate absorption effect accurately.On the other hand,the theory of reverse time migration is relatively easy,which has no limitation of dip angel and higher accuracy.Therefore,based on the analysis above,by combining the advantages of frequency-space domain forward simulation and reverse time migration,this article accomplishes these works: first,this article realizes viscoacoustic forward simulation in frequency-space domain;second,this article realizes viscoacoustic reverse time migration in frequency-space domain by combining constant Q model and stable compensation operator.Compared with the original work,the method presented in this article does not need to make approximation to constant Q model.Furthermore,it is able to handle the variation of Q model while the realization is simpler;finally,we prove,through numerical experiments,that frequency-space domain viscoacoustic reverse time migration has the ability to compensate absorption effect.