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Integration of Results from Two Seismic Inversion Methods – A Case Study
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 80th EAGE Conference and Exhibition 2018, Jun 2018, Volume 2018, p.1 - 5
Abstract
“Seismic inversion results are non-unique and can suffer from various pitfalls related to prior model assumptions or seismic data quality issues. Combining results from two entirely different inversion algorithms can substantially improve the understanding of these results. In this study, we use an inversion for probabilities of litho-facies, referred to as Pcube+, together with a classical elastic inversion. Pcube+ is a Bayesian method of updating prior probability models of lithology-fluid classes defined in the elastic parameter space. Outputs are posterior probability volumes for each pre-defined lithology-fluid class. A standard elastic inversion yields elastic parameter volumes, which can subsequently be transformed into probabilities of litho-facies using classification.
Comparing results from the two methods in areas away from well control has proven valuable in this case study. The main data source for pre-defining the lithology-fluid classes in PCube+ are well logs. However, wells tend to be biased and may not represent the full elastic parameter space that is required to explain the seismic data away from wells. In these situations, a cross-check with an elastic inversion gives crucial insight into which elastic parameter distributions are required to match the seismic AVO response, so that prior models for PCube+ can be fine-tuned.”