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Significance of Oil and Gas Separation

Published Date : October 16, 2018

Preamble:

Separators in the oil field refer to a pressure vessel utilized for the segregation of well liquids generated from gas and oil wells into liquid and gaseous components. Separation is essentially performed for the usage of segregated individual components in a wide range of applications. For instance, in petroleum production, the production fluids are isolated into their elemental components of gas, oil, and water. There are various notations for separators. This entails expansion separator or expansion vessel, stage separator, filter, trap, scrubber, knockout vessel, and flash chamber.

Working principle of separators:

A separator works on the concept of differences in densities. The different components will possess different densities and they will consequently move in accordance with that. Any particle of higher density would settle in the bottom whilst gas on top, oil in the middle and water in the bottom.

Significance of separation:

The production of hydrocarbons necessitates separation process. Separators are spherical or cylindrical pressure vessels that isolate water, oil and gas from the total fluid system.  Separators are generally positioned on an onshore processing station or an offshore platform. The most commonly used methods to remove gas from oil in separators are agitation, employment of heat, and centrifugal force. On the other hand, the methods employed to remove oil from gas in separators are gravity separation (density difference), change of flow direction, and employment of flow velocity, impingement, and change of flow velocity.  A separator encompasses the following crucial components:

Vessel with various segregation devices:

A vessel that furnishes various sections of separation devices entailing primary segregation device, secondary gravity settling section, mist extractor employed to eliminate tiny liquid particles from the gas, gas outlet, liquid settling section to eliminate vapor or gas from oil, oil outlet and water outlet.

Maintenance of volumetric liquid capacity:

Effective handling of liquid slugs from the flow lines or wells is accomplished by having the requisite range of volumetric liquid capacity.

Eliminating the flooding of mist extractor:

Appropriate height, length, and diameter of the vessel is necessary to permit most of the liquid to segregate from the gas lest so as not to flood the mist extractor.

Maintenance of oil level in the separator:

The usage of liquid level controller and a diaphragm motor valve on the oil outlet is to effectively manage the level of oil in the separator.

Steady pressure maintenance:

The maintenance of steady pressure in the vessel is carried out by a back pressure valve on the gas outlet.

Pressure relief devices:

Furthermore, pressure relief devices are employed to relieve the excessive pressure observed in the system.