− | The '''free water level''' is located at the base of a [[hydrocarbon column]] and the [[transition zone]]. Above this level, the reservoir produces water alone, hydrocarbon and water, or hydrocarbon alone on a [[production test]]. Below this level lies the aquifer of a [[water drive]] reservoir system. It produces water only. Zero [[buoyancy pressure]] exists at this level or below. | + | The '''free water level''' is located at the base of a [[hydrocarbon column]] and the [[transition zone]]. Above this level, the reservoir produces water alone, hydrocarbon and water, or hydrocarbon alone on a [[production test]]. Below this level lies the aquifer of a [[Drive mechanisms and recovery#Water drive|water drive]] reservoir system. It produces water only. Zero [[buoyancy pressure]] exists at this level or below. |