Oil-water two-phase flow often presents a internal corrosion problem in pipeline
transportation. The corrosion rate of the mild steel line is closely related to which phase wets
the pipe wall. The problem has been investigated here on a large scale, in a 60 meter-long
flow loop with crude oils. In this paper extensive experimental studies of flow pattern as well
as phase wetting determination have been carried out for different crude oils and different
pipe inclinations. Four experimental techniques have been applied to determine which phase,
water or oil, wets the pipe inner wall at different flowing conditions: wall conductance
probes, wall sampling, flow visualization, and corrosion monitoring by electric resistance
probes.