Pore characterization, acoustic and permeability measurements on core plug triplets, from the Miocene Tótkomlós (Calcareous Marl) Formation of the Pannonian-basin, Hungary

The Totkomlos Calcareous Marl (TCM), a Member of the Late Miocene Endrőd Formation was investigated as a potential cap and source rock and also as a local tight reservoir in the Pannonian Basin. Only a limited dataset is available for petrophysical characterisation of this formation. The study reports on a complex measurement campaign performed on three core triplet samples of the Totkomlos Calcareous Marl, including pore structure and petrophyiscal analysis at various pressure conditions. Direct laboratory measurements of compressional (P) and shear (S) wave velocities on oriented rock samples provide information about the anisotropic behaviour of the studied samples. A quantitative description of seismic anisotropy can improve the quality of seismic data processing. Pore structure investigations indicated plate-like materials with a typical pore throat size between 75-110 nm. Gas permeability measurements showed very low permeability values in the order of magnitude between 10 -16 -10 -18 m 2 . Weak acoustic anisotropy is observed both for P- and S- waves. Decreasing anisotropy with increasing confining pressure indicated that the samples become less anisotropic with increasing effective stress.