Μια νέα μέθοδος μέτρησης της κλασματικής διαβροχής πορώδων μέσων από πειράματα εκτόπισης δύο φάσεων

Abstract

A transparent porous medium of controlled fractional wettability is fabricated by mixing water-wet glass microspheres with strongly oil-wet polytetrafluouroethylene microspheres and packing them between two transparent glass plates. The displacement experiments performed for two pairs of fluids: a) silicon oil and water and b) paraffin oil and water. The growth pattern is video recorded and the transient response of the pressure drop across the pore network is measured for various fractions of oil-wet particles. The measured global capillary pressure fluctuates as the result of the variation of the equilibrium curvature of menisci between local maxima and local minima. By using wavelet transform on the capillary pressure signal, the best level detail spectrum arises and its peaks indict the parts of the original signal with the most important fluctuations, each of those is analyzed again. The best level detail coefficients give the “energy” of the analyzed part of the capillary pressure signal while the number of the most important fluctuations of the best level detail spectrum to the time interval they took place gives the “frequency” of the best level detail spectrum. The time averaged capillary pressure, the “energy” and the “frequency” are associated with the frontal wettability of the interface separating the two fluids before the invasion step and one number which denotes the regional wettability of the invaded area.