Method for determining the effective water saturation in a low- resistivity hydrocarbon-bearing rock formation based upon rock matrix conductance

摘要

A low-resistivity, hydrocarbon-bearing subsurface sand formation is logged with an electric logging system. Measurements are taken of formation porosity, water resistivity and formation resistivity. Core samples are taken from the formation water and electrical measurements are made on such core samples that reflect both a free-fluid pore network conductance and a rock matrix conductance. From the measurements, a formation water saturation corrected for rock matrix conductance is determined.