[[file:Mem91BuoyancyForcesFig26.jpg|thumb|{{figure number|1}}Water saturation decreases with height in an oil column. The volume of water is a function of the balance of capillary forces pulling the water up from the oil-water interface and the force of gravity acting together with the density contrast between the reservoir fluids, tending to pull the water down.]] | [[file:Mem91BuoyancyForcesFig26.jpg|thumb|{{figure number|1}}Water saturation decreases with height in an oil column. The volume of water is a function of the balance of capillary forces pulling the water up from the oil-water interface and the force of gravity acting together with the density contrast between the reservoir fluids, tending to pull the water down.]] |