Exploring multiple 3D inversion scenarios for enhanced interpretation of marine CSEM data: an iterative migration analysis of the Shtokman gas field

摘要

The premise of the various marine controlled-sourceelectromagnetic (CSEM) methods is sensitivity tothe lateral extents and thicknesses of resistive bodiesembedded in conductive hosts. For this reason, CSEMmethods were initially applied to de-risking exploration andappraisal with direct hydrocarbon indication. However,CSEM methods represent just part of an integrated explora-tion strategy. The value of CSEM data is only realizedwhen it is integrated with sound geological understandingin a shared earth model. The most successful applicationsof CSEM to date have been in complement to those seis-mic interpretations where lithological or fluid variationscannot be adequately discriminated by seismic methodsalone (Hesthammer et al. 2010). Methods for interpretingCSEM data are complicated by the very small responses ofhydrocarbon-bearing reservoir units when compared to thetotal fields. CSEM interpretation is inherently reliant oniterative inversion methods since the data cannot simply beseparated or transformed with linear operators as per seismicmethods.