It is believed that equipment now available can provide 

 bouyancy capable of supporting risers to a water depth of 

 6,000 ft. (Carmichael, 1975: 53). 



Conventional hydraulic controls for BOP valves cannot be 

 used in water deeper than 2,000 ft. because it takes too long 

 to respond to a problem and close the valves. A new electro- 

 hydraulic BOP control system has been developed which speeds 

 both response and function control. Its reliability and 

 response time is believed to be adequate in water depths 

 beyond 6,000 ft. (Carmichael, 1975: 53). 



The production phase of deepwater operations also requires 

 some major advancements in technology. Conventional platforms 

 have a practical depth limit of about 1,200 ft. (Langley, 

 1975: 41). Currently, efforts are underway to develop a 

 "guyed tower" platform for use in water depths of 600 to 2,000 



ft., and subsea production systems for use in water depths 

 of 3,000 ft. or more. The guyed tower platform (see Figure 

 2.6) is currently being tested by Exxon with a 370-ft. model 

 installed in 300 ft. of water off the coast of Louisiana. 

 It represents a one-fifth scale model of a platform designed 

 for 1,500 ft. of water. The platform sits on a base that is 

 held in place by bridge cables attached to anchors surrounding 

 the structure. The structure is compliant, that is, it moves 

 with the waves 1 to 2 degrees in any direction. The model 

 was installed in 1975 and has been through one winter. Most 

 data was acquired during the 1975 and 1976 winter months (and 



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