BLOCK-SIZE DETERMINATION IN FRACTURED POROUS-MEDIA

A how-reversal method involving the injection and retrieval of fluid f rom a fractured, porous medium at a different temperature to that of t he system in its undisturbed state is described and assessed as a pote ntial technique for measuring the thermal transients of blocks of frac tured porous media Formulae are obtained for the zeroth- and first-ord er-time moments of the thermal history of the fluid when it is well mi xed in the injection-retrieval hole, injected at a temperature T-1 (di fferent to the uniform temperature T-0 of the undisturbed system) at a fixed rate Q, for a time t(1), and then withdrawn through the same dr ill hole at the same fixed rate Q. These formulae have a potential for determining some geometric parameters of the block structure, includi ng the block surface-to-volume ratio and the mean action time for cond uctive heating.