We present a new alternative for the joint inversion of well logs to predict the volumetric and zone parameters in reservoir rocks. Porosity, water saturation, shale content, kerogen and matrix volumes are simultaneously estimated with the tool response function constants with a hyperparameter estimation assisted inversion of open-hole well logs. We treat the zone parameters, i.e., the physical properties of rock matrix constituents, shale, kerogen, and pore-fluids, as well as some textural parameters, as hyperparameters and estimate them using genetic algorithm for the entire processing interval. The significance of the inversion method is in that zone parameters are extracted directly from wireline logs, which both improves the solution of the forward problem and reduces the cost of core sampling and laboratory measurements. In a field study, we demonstrate the feasibility of the inversion method using real well logs collected from a Miocene formation situated in the Pannonian Basin, East Hungary.
Hyperparameter inversion of well logs for the simultaneous estimation of volumetric and zone parameters
