Facies – The Drivers for Modern Inversions

We address the problem of creating low frequency models for AVO inversions, investigating two workflows, neither of which involve well log interpolation. The first workflow creates a constant but structurally-compliant low frequncy model from averages over available logs. Facies analysis is done from the inversion outcomes. The second workflow takes the facies from the first workflow and together with per-facies trends creates a new model for a second pass of inversion. The results of the subsequent facies analysis are compared with the first in several ways and found to be superior. Notable in the analysis is the inclusions of several types of uncertainty which becomes useful in assessing risk.