An Integrated Approach for Carbonate Pore Systems Acoustic Characterization: Application to Late Paleozoic Carbonates
D. Mastellone, O. Borromeo, G. Mastellone, S. Duca and A. Ortenzi
Event name: Fourth EAGE Workshop on Rock Physics
Session: Carbonate Rock Physics
Publication date: 11 November 2017
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The pore space and acoustic properties of Late Paleozoic carbonates have been analysed to investigate relationships between geological factors and acoustic behaviour of a sample dataset comprising limestone, dolostone, spiculitic cherts and carbonate‐rich sandstones. Each sample was classified by lithology, pore type and geometry, to investigate geological controls in the Velocity/Porosity domain. Lithology produces a clustering in the velocity/porosity domain: for a given porosity, dolostone samples show higher velocity than limestone samples. Considering pore types, rocks dominated by vugs and molds show generally higher Vp and Vs in contrast to rocks dominated by interparticle and micropores. Petrophysical and acoustic data allowed calculation of the Frame Flexibility factor γk to characterize the flexibility of the rock frame as a result of the pore structure. Above a porosity threshold of about 10%, two clusters are detectable: one marked by low γk reflecting a stiffer rock frame, another marked by high γk reflecting a weaker rock frame. The clustering reflects mostly a mineralogy control with dolostones generally stiffer than limestones, however a minor influence of the dominant pore type is detectable in the limestone samples. These results suggest that diagenetic drivers like dolomitization, should be considered when interpreting seismic facies.