Suppressing artifacts in prestack reverse time migration

High Resolution/High Fidelity Seismic Imaging and Parameter Estimation for Geological Structure and Material Characterization

“…One of the major problems that affect the application of reverse-time migration is that the wideangle capability of full-wave propagator can generate spurious cross correlations from diving waves and back-scattered waves, and causes serious artifacts (Yoon, et al, 2004;Mulder and Plessix, 2004;Fletcher, et al, 2005;Wang, et al, 2005). Special techniques such as velocity model smoothing or interface impedance matching have been introduced to solve this problem.…”

“…Although the reverse-time migration is a relatively expensive method, the development of computer hardware and software (remarkably the popularities of PC clusters and Linux operating system) plus the ever increasing interests to explore complex structures in challenging regions stimulated recent interest to this method (e.g., Wu, et al, 1996;Mufti, et al, 1996;Sun and McMechanz, 2001;Biondi and Shan, 2002;Yoon, et al, 2003Yoon, et al, , 2004Mulder and Plessix, 2004;Fletcher, et al, 2005;Wang, et al, 2005;Hou and Marfurt, 2005). …”

“…Yoon, et al (2004) proposed to use an angle related weighting function calculated from Poynting vectors of source and receiver waves to pick the right events for imaging. Fletcher, et al (2005) tried to eliminate the artifacts by introducing a directional damping term in areas where unwanted reflections occur. Wang et al (2005) proposed a pseudospace method by using a space distortion to transform a heterogeneous velocity model into a homogeneous model where no reflections were generated.…”

Understanding the reverse time migration backscattering: noise or signal?

“…The cross-correlation between wavefields traveling in parallel directions is discarded because produce events that obstructs the geology. Other pre-imaging condition approaches are performed by modifying the wave equation to attenuate the reflections coming from sharp interfaces (Fletcher et al, 2005). A similar method applicable to post-stack migration uses impedance matching at sharp interfaces (Baysal et al, 1984).…”

“…Numerous techniques can be employed to remove the RTM noise. In terms of filtering approach, we could divide such methods in two categories: pre-imaging filtering (Fletcher et al, 2005;Liu et al, 2011;Yoon et al, 2004) and post-imaging filtering (Guitton et al, 2007;Kaelin & Carvajal, 2011;Youn & Zhou, 2001;Zhang & Sum, 2009). For detailed analysis of RTM backscattering events, the reader is referred to Díaz & Sava (2012).…”