The ensemble Kalman based method is the optimal method (in a mean squared error sense) under Gaussian assumption, but this does not mean that it does not work for non-Gaussian distributions. The only formal requirement is that the distribution is continuous. However, it is important to note that the performance of the ensemble Kalman methods are not optimal for multi-modal distributions. Furthermore, we typically advise the user to apply various transforms to parameters as part of the data conditioning process in ResX. Examples include log transformation for permeability, or probability transform for probabilities when configuring the model uncertainties in a ResX study.
Frequently asked question about ResX
Do the uncertain variables need to have a Gaussian distribution?
No! It is a common misconception that ensemble Kalman approaches require Gaussian prior distributions for them to work.
A short overview of ResXVideo
ResX brochureBrochure (PDF, 710.11 KB)
Streamlined reservoir modelling reduces planning turnaroundRead the case study Download case study as PDF (13.79 MB)
Improved volumes estimate by incorporating drill stem test dataRead the case study Download case study as PDF (10.35 MB)
URTEC-208291-MS Introducing Iterative Ensemble Kalman Smoother to History-Matching Horizontal Coalbed Methane Wells
SPE/AAPG/SEG Asia Pacific Unconventional Resources Technology Conference, November 16–18, 2021Conference paper
Locating enhanced-permeability streaks in a carbonate reservoirRead the case study Download case study as PDF (5.54 MB)
SPE-207738-MS Demonstrating Flexibility and Cost-efficiency Of Integrated Ensemble-based Modeling – One Approach On Three Reservoirs
Abu Dhabi International Petroleum Exhibition and Conference, November 15-18, 2021Conference paper
SPE-205212-MS History to Prediction Transition Calibration of Reservoir Simulation Model Ensemble
SPE Europec featured at 82nd EAGE Conference and Exhibition, Amsterdam, October 18–21, 2021Conference paper
SPE-205854-MS An Integrated Ensemble-Based Uncertainty Centric Approach to Address Multi-Disciplinary Reservoir Challenges While Accelerating Subsurface Modeling Process in an Onshore Field, Abu Dhabi, UAE
SPE Annual Technical Conference and Exhibition, Dubai, September 21–23, 2021Conference paper
SPE-200735-MS Implementation of Ensemble-Based Reservoir Modelling on the Ærfugl Field
SPE Norway Subsurface Conference, November 2–3, 2020Conference paper