130 



Present platform teclinology indicates the industry can develop the capability to 

 erect platforms in 600 feet (183 meters) of water/ hut beyond this depth, all 

 development w^ells may have to be drilled with mobile units and completed on 

 the ocean floor. 



Figure 2. Cost Data and Estimates for Self-Contained Platforms 



WATCR DEPTH - FEET 



Spaghl ItSBBt 



Figure 2 shows platform costs can be expected to increase sharply as the water 

 depth increases. The cost for existing platforms in the Gulf of Mexico vary [sic] 

 from $1.5 million in 100 feet (30 meters) of water to $4 million in 350 feet (107 

 meters) of water. The cost of platforms in 600 feet (183 meters) of water is 

 expected to approach $12 million, or six to eight times as costly as those in 100 

 feet of water. The graph also indicates the effect of environmental conditions on 

 platform costs, with platforms in Alaska's Cook Inlet costing about six times as 

 much as Gulf of Mexico platforms for the siame water depth. 



There are locations, such as in the Santa Barbara Channel of California, 

 where the seabed has a steep slope and where, even though a development pros- 

 pect may be in over 600 feet (183 meters) of water, it is possible to exploit it 

 with directional drilling from a platform in 600 feet of water. Nineteen of the 

 seventy-one leases purchased in the February 1968 Santa Barbara sale are in 

 waJter depths too great to support a 600-foot structure on the lease. These leases, 

 which represent about 10 percent of the total bonus paid, lie entirely within 5 

 miles of the 600-foot contour, and a number of operators are undoubtedly plan- 

 ning on developing many of the tracts by diredtional drilling from platforms in 

 600 feet of water or less, or by completing wells under water and producing 

 them to platforms in shallower water.* 



2. Underwater Completions 



Over 100 wells have been completed to date using underwater completion tech- 

 niques.® The techniques are well known, and the equipment has been proven. Be- 

 cause of the necessity of providing for well re-entry to repair downhole equip- 



^ See footnote 1. 



8 "Santa Barbara Channel-Promises and Problems," Ocean Industry (May 1968). 

 " M. E. Spaght, "The Development of Underwater Oil and Gas Reserves," presented 

 at Royal Swedish Acad, of Engrg. Sci. (1966). 



