Since 0.465 psi/ft is the hydrostatic pressure and there is a few miles of rock sitting on top of the oil, and rock is denser than water, wouldn't the oil pressure at the bottom of the hole be higher than the hydrostatic pressure?
The 0.465 psi/ft is the weight of a column of salt water. Sediments beneath the earth are porous and filled with salt water so it is as if the overburden of the rock is not there when calculating pore pressure. If there is a seal, then the rocks can become what is called geopressured, which is where the pore pressure is greater than 0.465 psi/ft and require weighting additives to the mud to control the pressure.