Pre-stack Least-Squares Reverse Time Migration in Presence of Strong Velocity Contrasts
R. Baina, V. Duprat and C. Agut
Event name: First EAGE/SBGf Workshop on Least-Squares Migration
Session: LSM for Complex Geology I
Publication date: 27 November 2018
Info: Extended abstract, PDF ( 1.02Mb )
Price: € 20
Least-Squares Migrations have been well studied for the last few decades and are essentially known for their good properties in improving the signal-to-noise ratio, increasing the resolution and giving more accurate and better-balanced amplitudes. We focus on Least-Square Reverse Time Migration for its ability to handle complex velocity fields with sharp velocity contrasts. In this paper we present a short list of issues faced on real data cases. We propose solutions to overcome them but mainly detail the problems coming from the limitations of Born modelling in such cases. We describe an innovative solution based on the use of an adaptive subtraction algorithm to deal with strong velocity contrasts in the background model. The efficiency of this method is proven on a simple synthetic example. Subsequent application on a real field will exhibit the potential of our approach for producing images with fewer artefacts and better reflectivity updates.