Description 



Gas processing plants are constructed if the offshore gas stream 

 contains a sufficient amount of recoverable petroleum liquids. Being 

 designed for the particular stream it processes, the plant may range in 

 capacity from two million to two billion cubic feet per day (cf/d). Gas 

 plants generally have a life of 10 to 20 years, depending primarily upon 

 the expected life of the producing reservoir. A gas processing plant 

 will have refrigeration units, compressors, power generators, a process 

 building and tanks for the storage of recovered liquid hydrocarbons. 



When gas is produced on an offshore platform, some partial 

 processing of the gas stream usually takes place on the platform. If 

 both gas and oil are produced, a separator is needed so the oil and gas 

 can be metered and pumped through separate lines. If water is also 

 produced with the oil and gas, a tank to remove water which is not 

 contained in an oil-water emulsion is often used. For distant offshore 

 production in the North Sea, Gulf of Mexico, and Pacific Coast the 

 practice has been to separate free water and natural gas from the oil on 

 the platform and then pipe the oil-water emulsion and gas to an onshore 

 facility for treatment. When partial processing takes place on the 

 platform, additional costs are incurred since space on a platform is 

 much more expensive than it is on land, and additional space is required 

 for both crew and equipment. Thus the tradeoffs between the differential 

 cost of processing facilities determines the location of partial processing 

 facilities [26]. 



Site Requirements 



Land, preferably flat and well-drained, is required for buildings, 

 storage facilities, pipes, towers, compressors, buffer zones, and 

 parking lots. Actual space required for processing is small; much more 

 space is required for safety reasons. The process, loading, utility, 

 storage, and office areas are usually separated, with extra land around 

 the plant perimeter. The amount of land required for a gas plant is 

 related, but not directly proportional to volume of gas handled per day. 



Gas processing plants require sites of 75 acres or less, of which 

 10 to 20 acres may be intensively used for buildings and structures. 

 The remaining acreage is usually buffer zone. If necessary, partial 

 treatment facilities can be constructed on sites as small as 2 to 4 

 acres. 



When capacity exceeds 600 to 700 million cf/d, an additional 

 processing unit is usually required , which takes up additional land. A 

 typical plant handling a billion cf/d might require a total of 75 acres, 

 of which 20 would be used for buildings and structures. A plant handling 

 200 million cf/d would require 50 acres [50]. 



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