Vp/Vs Automatic Picking of Ultrasonic Measurements and their Correlation of Petrographic Coded Carbonates from Austria

Compressional wave velocity (vp) and shear wave velocity (vs) are important parameters for reservoir management as well as successful exploration and exploitation. As the measurement of vp is a standard procedure, the reliable and accurate measurement of vs is still a non-trivial task. Especially carbonates form a difficult, but important group of rocks. Laboratory measurements of vs show – depending on the quality of the shear wave probe – first arrivals of vp as well as vs. The onset those two different phases can be identified by the Akaike Information Criterion picker (AIC). The AIC is an autoregressive method, dividing datasets into locally stationary segments. Displaying vp versus vs shows that it is important to separate carbonates into different lithologies introducing an “petrographic coded” environment. This environment shows that commonly used linear empirical correlations – mainly calculated for saturated samples – do not fit the requirements for adaptive regression to data analysis for carbonates. Therefore, the introduction of inclusions model is required, especially for the separation of carbonates into dolomite and limestone.