Recent studies of hydrothermal fluid chemistry at the Axial Seamount Hydrothermal Emissions Study (ASHES) vent field of Axial Volcano indicate separation of liquid and vapor phases during the migration of fluids to the seafloor. The brine phase liquid emanates from discrete sulfide chimneys, while fluid which has been through vapor phase separation flows diffusively from fissures in the surrounding basalt. One possible mechanism to explain this spatial segregation of the fluid phases is based on the relative permeability terms in the equations of two-phase flow. A qualitative model for the distribution of fluids observed at ASHES is postulated in which brine phase fluids are confined within flow conduits by a surrounding relative permeability barrier, while vapor phase fluids flow diffusely into the surrounding host rock. ¿ American Geophysical Union 1990