Whether both oil and gas are found 



Availability of coastal frontage (land) 



Availability of additional (back-up) land 



Proximity to existing refineries and processing plants 



Proximity to diverse urban areas and markets 



Public services and facilities (schools, hospitals) 



Labor markets (areas without strong labor unions are preferred) 



Publ ic opinion 



Availability of entertainment 



Proximity to airport or landing strip 



FACILITY REQUIREMENTS 



This section describes typical onshore OCS facilities. Facility require- 

 ments, siting considerations, and impacts. 



Service bases 



Service bases provide transportation, services, and storage for drilling 

 equipment, supplies, personnel, and other necessities to and from OCS oil and 

 gas rigs and platforms. Transportation to offshore operations usually depends 

 upon supply boats for equipment and materials and crewboats and helicopters 

 for personnel. Usually at least two supply boats, one crew boat, and one 

 helicopter are necessary to support each drilling rig or platform. Where 

 drilling is located far offshore, more vessels and helicopters may be needed 

 because of excessive travel time. Transportation onshore is by rail, road, 

 air, and water. 



Service bases require at least two berths, each about 122 m (400 ft) 

 long, per rig. Fewer vessels and helicopters may be required if several rigs 

 are serviced from the same service base. Depending on the distance to the rig 

 and the nature of offshore OCS operations, at least two vessel trips and one 

 helicopter trip per rig are required daily. The typical types and quantities 

 of materials transported offshore to a drilling rig in one year are shown in 

 Table 7. 



Table 7. Types and quantities of materials transported annually offshore to 

 an exploration rig (New England River Basins Commission 1976b). 



Material s 



Type Quantity 



Fuel 10,000-15,000 bbl 



Drilling mud 2,000-5,000 tons 



Cement 1,000-3,000 tons 



Fresh water 5,000,000-7,500,000 gal 

 Tubular goods 2,000-3,000 tons 



147 



