Geophysical Prospecting, 2013, 61 (Suppl. 1), 317–333 doi: 10.1111/j.1365-2478.2012.01119.x Estimated source wavelet-incorporated reverse-time migration with a virtual source imaging condition Youngseo Kim ∗ , Yongchae Cho and Changsoo Shin Seoul National University, Research Institute of Energy and Resources 151-744/36-2061 College of Engineering, Seoul National University, Daehak-dong Gwanak-gu, Seoul, Republic of Korea Received July 2011, revision accepted May 2012 ABSTRACT Many geophysicists perform reverse-time migration using a variety of artificial sources to obtain the source wavefield. Upon processing the seismic data, however, it is difficult to recover the original phase and amplitude of the source wavelet used for seismic exploration, regardless of the source. We have therefore used several artificial source wavelets such as Ricker or the first derivative Gauss wavelets expressed by well-known functions. There are some differences between these artificial source wavelets and the original source wavelets, resulting in imperfect migration images. Artificial source wavelets tend to distort the exact location of subsurface reflectors and they create noise around the boundary of the stratum. To solve this problem, we applied the source estimation technique to the reverse-time migration algorithm. The source estimation technique approximates the source wavelet to the original exploration source wavelet by a deconvolution method. This technique is used in full waveform inversion and provides better inversion results as demonstrated by other studies. To prove the effect of reverse-time migration with source estimation, we tested this algorithm on the Sigsbee2a model, SEG/EAGE 3D salt model and 3D real field land data. Using the resulting images of these three models, we found that the source estimation technique can yield better migration images. To suppress the artefacts produced in the migration image, we used a wavenumber filter and Laplacian filter on 2D and 3D examples, respectively. Furthermore, we used the pseudo-Hessian similar to the source illumination to scale the migration image because the virtual source imaging condition was used for reverse-time migration. Key words: Reverse-time migration, Amplitude, Source wavelet INTRODUCTION Reverse-time migration is a depth migration method that uses a two-way wave equation, which was first used for 2D post- stack depth migration in the late 1970s (Baysal, Kosloff and Sherwood 1983; McMechan 1983; Whitmore 1983). The migrated image is obtained by propagating the receiver wave- fields from their own positions to the earth using the time- reversed two-way wave equation. This method can preserve the real amplitude of seismic wavefields, handle multiple ar- ∗ E-mail: kysgood0@snu.ac.kr rivals and migrate all types of multiples to their correct loca- tion (Guitton, Kaelin and Biondi 2007). Because this method propagates waves in all directions, it has considerable abil- ity to image steeply dipping reflectors and to address strong lateral velocity variation. Given that reverse-time migration requires a large amount of computing time and disk space in practical implementation, many service companies use one- way wave equation prestack depth migration. However, be- cause the one-way equation prestack depth migration tech- nique is limited to describing salt flanks or dips greater than 70 ◦ , it is difficult or impossible to identify hydrocarbon traps against salt flanks. C  2013 European Association of Geoscientists & Engineers 317