Relax OzExpat,
Have another Lager....
Water replaces the oil. Oil is usually held under pressure by non-porous reservoir caps by a water table underneath(crude oil is less dense than water). Also, the reservoirs are more like porous sandstone than cavernous space. A well penetrates the non porous reservoir cap and the oil flows up to ground level. As the well gets older, there is considerably more water in the oil, and eventually it is mostly just water with dissolved natural gas. After the oil company is done with the reservoir, it is caped off and left pretty much full of water.
PS- This is not drinkable water..highly corrosive and full of dissolved hydrocarbons.
WP
Last edited by Wanikiba_pilot; 1st Feb 2005 at 21:14.