IN-SITU METHOD FOR DETERMING PORE SIZE DISTRIBUTION CAPILLARY PRESSURE AND PERMEABILITY OF A FORMATION SURROUNDING A BORE HOLE

摘要

An in-situ method of determining the pore size distribution, capillary pressure curve, and permeability of a formation using induced polarization logging measurements. The induced polarization (IP) voltage decay curve is measured opposite the formation of interest and the voltage decay curve is decomposed into a series of relaxation times related to the pore size distribution. The capillary pressure curve and the permeability are approximated from the pore size distribution. The measurements can also be made in the frequency domain using various frequencies to obtain the variation in phase shift with frequency. The variation in phase shift with frequency can be correlated with previous core measurements to obtain the pore size distribution, capillary pressure curve and formation permeability.