Probabilistic Comparison of Stress Dependent Rock Physics Models
D.A.C. Angus and D. Price
Event name: 78th EAGE Conference and Exhibition 2016
Session: Rock Physics III - Interpretation and Stress Dependency
Publication date: 31 May 2016
Info: Extended abstract, PDF ( 3.06Mb )
Price: € 20
In this study, we investigate the stability of three common stress-dependent rock physics models through a probabilistic analysis of how well constrained each model parameter is using core data. We do this by inverting for model solutions using ultra-sonic velocity-stress measurements. All models show a relatively good fit to the observed data. However, two of the models show slightly poor data fit to the S-wave data. This suggests the parameters of the model do not accurately define the trade off in the curvature between the P- and S-wave relationships. All sets of parameters show similar constraint, which produce almost identical error bounds to their velocity-stress relationships. These relatively small constraint values with respect to the total parameter space demonstrate that each model inversion has a unique and constrained solution for each material. Two of these models have parameters that are measurable from suitable mineralogical data. However, these constraint values indicate that these rock physical properties may need to be accurately measured to assume a relatively similar tight data fit. These general parameter constrains can also be used to calculate error in 4D velocity change.