Fig. 4: Thermo-mechanical behavior of the binary solutions and mud suspensions.

a The temperature changes at the bottom of low-concentration binary samples over time. b The temperature changes for the high-concentration samples for fast (pale colors) and slow (bright colors) pressure drops. Dashed lines correspond to the approximate time when the pressure of 20 mbar was reached and the dotted(-dashed) curve(s) represent the pressure drop itself. The boiling corner is an approximation of the onset of boiling (1st phase transition) in the dominant part of a sample volume, associated with a rapid temperature drop. The terminal temperatures denote the freezing (2nd phase transition) of the sample and the restoration of equilibrium below the isolation (ice) layer when boiling is terminated and the temperature stabilizes. c Results of the p-T modeling with projected experimental data of the tube experiments. Solid lines are interfaces between the stable liquid-vapor fields (at 1 bar) and dashed lines represent the H₂O liquidus where ice and brine mixtures are formed. Calculated and experimental data are both low-concentration (pale) and high-concentration (bright) solutions. Dots parallel to the dotted lines correspond to the terminal temperatures when the sample is re-pressurized. d Results of the rheology tests for the bentonite-salt-water suspensions. Displayed are approximated envelopes for the individual fields of the viscosity-shear rate dependence diagram (in cut-detail derived from Fig. S3 in the Supplementary texts). NaCl and MgSO₄ have a unified envelope for all the concentrations due to small variations of the viscosity dependence (the detailed view showing viscosity ranges is provided in the inset). The pure bentonite salt-free suspension that is not shown in this detailed inset has typically viscosity of 1–10 Pa.s for decreasing shear rate in the range of 80–10 s⁻¹ (for raw rheology data and saltless suspension see the Supplementary texts: notes 1 and 2).