Imaging blended VSP data using full wavefield migration

Abstract

SUMMARYBlended source and/or simultaneous source acquisition for multi-offset and multi-azimuth VSP measurements can prove significantly beneficial in saving expensive borehole downtime. In the last few years, for the case of surface seismic data, it was proposed to redefine imaging and inversion of the blended data to handle the data directly without any need to separate the blended sources. Recently, we proposed the concept of full wavefield migration (FWM) to image VSP data, where using all the multiples -both surface and internal multiples -in the imaging provides better illumination, especially away from the well. Using the above mentioned two concepts, in this paper, we will show the potential of FWM to directly image blended VSP data, without the need for intermediate deblending.We can see FWM imaging as a deblending algorithm itself that transforms the blended data into the reflectivity image space by an inversion process. The concept of FWM formulated in terms of a constrained least-squares inversion scheme indeed enables us to use any kind of complex source wavefield to explain the subsurface reflectivity. The method is illustrated successfully for some synthetic blended VSP examples.

3D Surface-wave Estimation and Separation Using a Closed-loop Approach

“…The iterative closed-loop approach has been developed for several stages of seismic processing (Berkhout 2013), see e.g. Kontakis and Verschuur (2014) for deblending, Lopez and Verschuur (2014) for multiple estimation and separation, Mulder and Plessix (2004), Davydenko and Verschuur (2014) and Soni and Verschuur (2014) for fullwavefield migration, Staal et al (2014) for joint migration inversion. In this approach, at each seismic processing stage, an optimum parameterization is used to describe the inverse problem.…”

3D surface‐wave estimation and separation using a closed‐loop approach

“…To address the challenges of surface waves and adopt recent advances in seismic processing, we propose a method of 3D surface‐wave estimation and separation using the so‐called closed‐loop approach. The iterative closed‐loop approach has been developed for several stages of seismic processing (Berkhout ) (see, e.g., Kontakis and Verschuur () for deblending, Lopez and Verschuur () for multiple estimation and separation, Mulder and Plessix (), Davydenko and Verschuur () and Soni and Verschuur () for full‐wavefield migration, and Staal et al . () for joint migration inversion).…”