Plug-level residual structure of fluid-substitution models in heterogeneous carbonate rocks — data and code

Ultrasonic and petrophysical measurements on seven outcrop plugs — six carbonates from the Jandaíra Formation and one sandstone from the Antenor Navarro Formation, NE Brazil — together with the Python code that analyses them. Compressional and two orthogonally polarised shear velocities were measured under controlled confining pressure, pore pressure, and temperature in the dry and water-saturated states, yielding 45 sample–pressure pairs common to both acquisitions. The deposit contains the velocity tables, the raw waveform records, the petrophysical characterisation of each plug, and code that predicts the saturated velocities from the dry-rock properties under four fluid-substitution models (Gassmann, high-frequency Biot, Brown–Korringa and Müller–Sahay) and analyses the structure of the residuals at the level of the plug: cluster bootstrap, BCa intervals, exact permutation tests, mixed-effects models, Monte Carlo propagation of the acquisition uncertainties, and sensitivity analyses on tortuosity, mineralogy and the high-pressure frame modulus. A single script regenerates all reported tables and figures from the measurements, and 12 regression tests verify the results against the published values. Accompanies the article "Plug-level residual structure of fluid-substitution models in heterogeneous carbonate rocks", submitted to Geophysical Prospecting.