PRESSURE AND TEMPERATURE DYNAMICS IN FLUID-SATURATED POROUS-PERMEABLEROCKS

A nonlinear model of temperature and pressure waves in one-dimensional fluid-saturated porous-permeable rocks is discussed in order to inves tigate hydrogeological problems affecting hyperthermal areas. Nonlinea r solutions, consisting in waves moving with constant velocity V, are analyzed. They behave as perturbations that increase with time till a critical value for vertical pressure gradient is reached, a gradient t hat is related to the time-asymptotic Darcy velocity. From the geologi cal point of view, the effect of rock fracturing phenomena can be sche matized by using some of the solutions of our model, if one postulates that our coefficients depend on the waves vertical pressure gradients . This allows to interpret measurement of the time-evolution of the Da rcy velocity, as measured in a superficial position, as a way to recon struct the porous rock reaction to the temperature-pressure jump carri ed by these nonlinear waves.