Electrical Conductivity of Rock-Solution Systems under Ambient Conditions: Pictured Cliffs Sandstone in Tap Water.

摘要

As part of a program to explore the range of applicability of Archie's Law,the electrical conductivity (sigma) of cylindrical, 25.4-mm-diameter cores cut from Pictured Cliffs sandstone (porosity range 3.8percent to 4.9percent) was measured at a frequency of 1kHz under ambient conditions after immersion in tap water. The sigma of the solutions was also measured. Formation factors (F) and the sigma of rock specimens displayed time-dependent behavior for up to 4500 h. The time required for sigma to reach maximum values was found to increase with the porosity of the rock sample. The observed time-dependence of F was influenced by the kinetics of ion transport between the Pictured Cliffs sandstone and the aqueous pore fluid. Soxhlet extraction of the sample before immersion lowered the magnitude of increase in F as a function of time,but it did not guarantee time-independent behavior. (ERA citation 01:020078)