Production in which oil moves from the reservoir, into the wellbore, under naturally occurring reservoir pressure.
Recovery of petroleum oil from underground reservoirs by taking advantage of the natural energy (pressures) in these reservoirs. The most common types of these sources of reservoir pressures are solution-gas drive, gas-cap-expansion drive, and water (aquifer) drive. More than one of these natural drives may occur in a single reservoir. See also secondary recovery and tertiary recovery.
The period of production in which oil moves from its reservoir through the wellbore under naturally occurring reservoir pressure.
Recovery of hydrocarbons from a reservoir using only natural reservoir pressure.(see also Secondary and Tertiary Recovery.)
The recovery of reserves using the natural energy of the reservoir. The hydrocarbons flow from the higher-pressure source reservoir to the lower-pressure surface facilities due to the pressure differential. The flow of hydrocarbons is also often aided with simple pumping techniques.
The crude oil or natural gas recovered by any method that may be employed to produce them where the fluid enters the well bore by the action of natural reservoir pressure (energy or gravity).
Recovery of oil or gas from a reservoir purely by using the natural pressure in the reservoir to force the oil or gas out.
the first stage of oil production in which natural reservoir drives are used to recover oil, although some form of artificial lift may be required to exploit declining reservoir drives.
The production of oil and gas from reservoirs using the natural energy available in the reservoirs and pumping techniques.
The standard oil well production technique, sometimes called flush production, using only the natural water or gas pressure in the reservoir to force the petroleum to the surface. Primary recovery typically yields approximately 20% of the oil in a conventional light crude reservoir, but only about 5% of the oil in a heavy crude reservoir. Primary recovery is usually first augmented by wellhead pumps.