on of this area by geologic and / or geographic provinces (see Reference 3). Those areas shown in red are areas where ice is expected to be the significant environmental constraint. This includes the A rctic Margin, the Bering Sea S helf, B ristol Bay and to some extent the Aleutian Shelves. Those areas shown in blue are areas where winds, waves, currents, and / or earthquakes are expected to be the significant environmental constraint. Question we areaddressingourselve sto is, «How much of this area is within reach of today» scapability and how much is within reach of the expected short - termextensions of today «scapability? » L e t us consider f i r s t the blue a r e a s. Fixed platforms have been installedin the Gulf of Mexico in up to 373 feet of water. Present designs for the North Sea where wind and wave conditions are expected to be similar to Gulf of Alaska conditions are approaching the 500-foot mark. In the Santa Barbara Channel platforms have been installed in about 200 feet of water and a permit has been filedfora platform installationin approximately 850 feet of water. I n terms of extremes, assuming completion of the above plans, platform feasibilitywill have been demonstrated in 500 feet of water for North Sea type wind and wave environments and 850 feet of water in an earthquake environment. I n terms of today »scapability, I think it is reasonable to say that, with minor exception if any, platform systems can be successfully designed and installed anywhere on the continentalshelf of the conterminous US and the South Alaskan coast. A s shown on Figure 51, thiscapability would account foratotal of 239,000,000 acres orbetter than 114. , < of the t o t a l a r e a. I naddition, some additional red area is within reach of this same capability. I n Cook I nlet, platforms have been installedin up to 125 feet of water, equivalent to about 150 feet because of the additional depth caused by largetides. These platforms have been designed for ice flows 3 to 4 feet thick carried by currents of up to 10 to 12 feet per second. Much additional work has been done regarding other types of structures which can be utilized on the A rctic Margins such as the gravel filledislandinstalled recently by Imperial O il of Canada. Although somewhat more speculative, I think thatplat - form systems are probably feasiblein up to 200 feet of water in the B ristol Bay area and the A leutian Shelves and rigid island-type structuresare probably feasiblein up to 50 feet of water in the remainder of the A rctic. A s shown in Figure 51, thisadditionalarearep resents some 35,000,000 acres and atotal of 274,000,000 acreswithin reach of today «scapability. Let us now look at the short - termextensionstoexist ingcapability. I nthis context, we mean that over thenext four or five-year period given exi sting R & D programs and operationalplans, the additionalcapabilityt hatwill ensue will be a function of these currentefforts. What will happen beyond that point is quite another matter, however, since new programs will be required and the success of existing programs will have to be demonstrated. Figure 52 summarizes the capabilityprojection of the system previously discussed. The capabilitytodrill, test and evaluate from afloatingvesselin 1500 feet of water has been demonstrated. The SEDCO 445 has the capabilitytodrillin 2000 feet of water, and the design allows for extension to considerably greater depths. Also, thereareseverale...
