FACIES & FLUIDS PROBABILITIES

Facies & Fluids Probabilities (FFP) is an interactive interpretation tool for determining lithofacies from the outcomes of acoustic and elastic inversions. Facies are usually defined in the petrophysical domain, after which proxies are confirmed in the elastic domain. Typically P Impedance and Vp/Vs are used. For unconventional scenarios the key elastic proxies could be geomechanical.

Estimating Rock and Fluids Probabilities from Inversion

Multi-dimensional probability density functions (PDFs) are designed for each possible facies. Then a Bayesian inference technique is used to determine the probabilities of occurrence of each of the facies at each 3D grid point in time or depth. A most-probable facies volume is also output.

Facies properties in FFP analysis space (Vp/Vs and P Impedance in the example) are defined by multi-dimensional probability density functions (PDFs). In this figure, the first two standard deviations corresponding to each of the three PDFs are shown.

Key capabilities in FFP include:

• Horizon and Volume Priors
• Facies analysis on the input logs (close the loop QC)
• PDF import and save
• Inversion Uncertainty Estimation and inclusion
• Inversion Bias Check and Fix
• Unclassifiable grid point identification upgrade
• Editing in non-parametric (binning) mode
• Quality control