Uncertainty Quantification in Rock Physics Modelling

Rock Physics describes how reservoir rock properties, such as porosity and mineralogy, affect elastic properties, such as seismic wave velocities. If the rock properties are known, then we can predict the corresponding elastic properties and the seismic response using a rock physics model. Since measurements of rock properties in the reservoir are uncertain, we propose to apply rock physics models to random variables rather than deterministic values. If the input random variable can be described by a probability distribution, then we can formulate a probabilistic approach to rock physics models to estimate the exact probability distribution of the rock physics predictions. In this paper, we present the probability theory of this new approach, the application to two common models, such as Gassmann’s equation and Raymer’s relation, an illustrative example and a real case study.