Imaging Vertical Seismic Profiling Data Using Full Wavefield Migration
D.J. Verschuur and A.K. Soni
Event name: 75th EAGE Conference & Exhibition incorporating SPE EUROPEC 2013
Session: Borehole Seismic - Acquisition, Processing & Interpretation
Publication date: 10 June 2013
Info: Extended abstract, PDF ( 2.03Mb )
Price: € 20
VSP data can provide a high-resolution reservoir image due to relatively lower wavefield distortion in the overburden. However, conventional imaging of VSP data using the primary-only data suffers from poor illumination, imaging artifacts and low reliability, especially away from the well. Recently, we have proposed to image VSP data using the full wavefield migration (FWM). The algorithm falls in the category of full waveform inversion – i.e. it explains every sample of the input data – using the true amplitude angle-dependent reflectivity of the subsurface, as the parameters to be determined. The FWM algorithm is recursive in depth and iteratively incorporates the nonlinear transmission effect at each depth level. During the inversion scheme in FWM the up- and downgoing wavefields are updated at each depth level. The use of the full wavefield in imaging the VSP data can enhance illumination as well as the image reliability. In this paper we discuss the forward modelling and the inversion scheme using synthetic data examples. Also, we illustrate the advantage of using all multiples in this inversion-based migration scheme and further demonstrate the potential of using deviated wells, as opposed to true vertical wells, for obtaining a high-resolution image of complex reservoirs.