diagraphie de polarisation spontanée

CONT: The log works by measuring small electric potentials (measured in millivolts) between depths in the borehole and a grounded voltage at the surface. Conductive fluids are necessary in bore hole to create a SP response, so the SP log cannot be used in nonconductive drilling muds (e.g. oil-based mud) or air filled holes.
OBS: Using the data from this log and from other electric logs the geologist is able to determine the nature of the formation being drilled through and assess its likely porosity and permeability.