Oil production plant
Encyclopedia
An oil production plant is a facility which performs processing of production fluid
s from oil well
s in order to separate out key components and prepare them for export. This is distinct from an oil depot
, which do not have processing facilities.
Typical production fluid
s are a mixture of oil, gas
and produced water
. Many permanent offshore platforms have full oil production facilities onboard. Smaller platforms and subsea
wells must export raw production fluid to the nearest production facility, which may be on a nearby offshore processing platform or an onshore terminal.
, which regulates the rate of flow. The flowlines are gathered in a manifold and routed into a separator, which will gravity separate the three components. Once the oil has been separated from the gas and produced water, it is usually routed to a coalescer
before being metered and pumped to the onshore terminal.
The produced water is often routed to a hydrocyclone to remove entrained oil and solids and then either re-injected into the reservoir
or dumped overboard depending on the circumstances and cleanliness of the water. The associated gas
is initially dubbed "wet gas" as it is saturated with water and liquid alkane
s. The gas is typically routed through scrubbers
, compressors and coolers which will remove the bulk of the liquids. This "dry gas" may be exported, re-injected into the reservoir
, used for gas lift
, flared or used as fuel for the installation's power generators.
Onshore terminals generally have fired heaters followed by separators and coalescers to stabilise the crude and remove any produced water not separated offshore. Onshore separators tend to operate at a lower pressure than the offshore separators and so more gas is evolved. The associated gas is generally compressed, dew-pointed and exported via a dedicated pipeline. If gas export is uneconomical then it may be flared. Onshore terminals frequently have large crude oil storage tanks to allow offshore production to continue if the export route becomes unavailable. Export to the refinery is either by pipeline or tanker.
Production fluid
Production fluid is the fluid mixture of oil, gas and water in formation fluid that flows to the surface of an oil well from a reservoir. Its consistency and composition varies.Fluids may be described by a multitude of characteristics including:...
s from oil well
Oil well
An oil well is a general term for any boring through the earth's surface that is designed to find and acquire petroleum oil hydrocarbons. Usually some natural gas is produced along with the oil. A well that is designed to produce mainly or only gas may be termed a gas well.-History:The earliest...
s in order to separate out key components and prepare them for export. This is distinct from an oil depot
Oil depot
An oil depot is an industrial facility for the storage of oil and/or petrochemical products and from which these products are usually transported to end users or further storage facilities...
, which do not have processing facilities.
Typical production fluid
Production fluid
Production fluid is the fluid mixture of oil, gas and water in formation fluid that flows to the surface of an oil well from a reservoir. Its consistency and composition varies.Fluids may be described by a multitude of characteristics including:...
s are a mixture of oil, gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
and produced water
Produced water
Produced water is a term used in the oil industry to describe water that is produced along with the oil and gas. Oil and gas reservoirs have a natural water layer that lies under the hydrocarbons. Oil reservoirs frequently contain large volumes of water, while gas reservoirs tend to have smaller...
. Many permanent offshore platforms have full oil production facilities onboard. Smaller platforms and subsea
Subsea
Subsea is a general term frequently used to refer to equipment, technology, and methods employed in marine biology, undersea geology, offshore oil and gas developments, underwater mining, and offshore wind power industries.- Oil and gas :...
wells must export raw production fluid to the nearest production facility, which may be on a nearby offshore processing platform or an onshore terminal.
Process
The production plant is said to begin after the production wing valve on the oil well. The product from each well is piped through the choke valveChoke valve
A Choke valve is a type of valve designed to create choked flow in a fluid. Over a wide range of valve settings the flow through the valve can be understood by ignoring the viscosity of the fluid passing through the valve; the rate of flow is determined only by the ambient pressure on the upstream...
, which regulates the rate of flow. The flowlines are gathered in a manifold and routed into a separator, which will gravity separate the three components. Once the oil has been separated from the gas and produced water, it is usually routed to a coalescer
Coalescer
A Coalescer is a technological device performing coalescence. They are primarily used to separate emulsions into their components via various processes; operating in reverse to an emulsifier....
before being metered and pumped to the onshore terminal.
The produced water is often routed to a hydrocyclone to remove entrained oil and solids and then either re-injected into the reservoir
Oil reservoir
A petroleum reservoir, or oil and gas reservoir, is a subsurface pool of hydrocarbons contained in porous or fractured rock formations. The naturally occurring hydrocarbons, such as crude oil or natural gas, are trapped by overlying rock formations with lower permeability...
or dumped overboard depending on the circumstances and cleanliness of the water. The associated gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
is initially dubbed "wet gas" as it is saturated with water and liquid alkane
Alkane
Alkanes are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds without any cycles...
s. The gas is typically routed through scrubbers
Vapor-liquid separator
A vapor–liquid separator is a device used in several industrial applications to separate a vapor–liquid mixture.For the common variety, gravity is utilized in a vertical vessel to cause the liquid to settle to the bottom of the vessel, where it is withdrawn....
, compressors and coolers which will remove the bulk of the liquids. This "dry gas" may be exported, re-injected into the reservoir
Oil reservoir
A petroleum reservoir, or oil and gas reservoir, is a subsurface pool of hydrocarbons contained in porous or fractured rock formations. The naturally occurring hydrocarbons, such as crude oil or natural gas, are trapped by overlying rock formations with lower permeability...
, used for gas lift
Gas lift
Gas lift is one of a number of processes used to artificially lift oil or water from wells where there is insufficient reservoir pressure to produce the well. The process involves injecting gas through the tubing-casing annulus. Injected gas aerates the fluid to reduce its density; the formation...
, flared or used as fuel for the installation's power generators.
Onshore terminals generally have fired heaters followed by separators and coalescers to stabilise the crude and remove any produced water not separated offshore. Onshore separators tend to operate at a lower pressure than the offshore separators and so more gas is evolved. The associated gas is generally compressed, dew-pointed and exported via a dedicated pipeline. If gas export is uneconomical then it may be flared. Onshore terminals frequently have large crude oil storage tanks to allow offshore production to continue if the export route becomes unavailable. Export to the refinery is either by pipeline or tanker.