Offshore drilling and producing technology of total company

Figure 50 d e p i c t s the d i s t r i b u t i o n of t h i s area by geologic and/or geographic provinces (see Reference 3). Those areas shown i n red a r e areas where ice is expected to be the s i g n i f i c a n t environmental c o n s t r a i n t . This includes the A r c t i c Margin, the Bering Sea S h e l f , B r i s t o l Bay and to some e x t e n t the Aleutian Shelves. Those areas shown i n blue a r e areas where winds, waves, currents , and/or earthquakes a r e expected to be the s i g n i f i c a n t environmental constraint .

The question we a r e a d d r e s s i n g o u r s e l v e s t o is, "How much of t h i s area is within reach of today's c a p a b i l i t y and how much is within reach of the expected s h o r t - t e r m e x t e n s i o n s of today's c a p a b i l i t y ? " L e t us consider f i r s t the blue a r e a s . Fixed platforms have been i n s t a l l e d i n the Gulf of Mexico i n up to 373 f e e t of water. Present designs f o r the North Sea where wind and wave conditions a r e expected t o be s i m i l a r to Gulf of Alaska conditions a r e approaching the 500-foot mark. In the Santa Barbara Channel platforms have been i n s t a l l e d in about 200 f e e t of water and a permit has been f i l e d f o r a platform i n s t a l l a t i o n i n approximately 850 f e e t of water. I n terms of extremes, assuming completion of the above p l a n s , platform f e a s i b i l i t y w i l l have been demonstrated i n 500 f e e t of water f o r North Sea type wind and wave environments and 850 f e e t of water i n an earthquake environment. I n terms of today's c a p a b i l i t y , I think it i s reasonable to say t h a t , with minor exception i f any, platform systems can be s u c c e s s f u l l y designed and i n s t a l l e d anywhere on the c o n t i n e n t a l s h e l f of the conterminous U.S. and the South Alaskan coast. A s shown on Figure 51, t h i s c a p a b i l i t y would account f o r a t o t a l of 239,000,000 acres o r b e t t e r than 114 . , < of the t o t a l a r e a . I n a d d i t i o n , some a d d i t i o n a l red area is within reach of t h i s same c a p a b i l i t y . I n Cook I n l e t , platforms have been i n s t a l l e d i n up t o 125 f e e t of w a t e r , e q u i v a l e n t to about 150 f e e t because of the a d d i t i o n a l depth caused by l a r g e t i d e s . These platforms have been designed f o r ice flows 3 to 4 f e e t thick c a r r i e d by c u r r e n t s of up to 10 t o 12 f e e t per second. Much a d d i t i o n a l work has been done regarding o t h e r types of s t r u c t u r e s which can be u t i l i z e d on the A r c t i c Margins such as the gravel f i l l e d i s l a n d i n s t a l l e d r e c e n t l y by Imperial O i l of Canada. Although somewhat more s p e c u l a t i v e , I think t h a t p l a t - form systems a r e probably f e a s i b l e i n up to 200 f e e t of water i n the B r i s t o l Bay area and t h e A l e u t i a n Shelves and r i g i d island-type s t r u c t u r e s a r e probably f e a s i b l e i n up t o 50 f e e t of water i n the remainder of t h e A r c t i c . A s shown i n Figure 51, t h i s a d d i t i o n a l a r e a r e p r e s e n t s some 35,000,000 acres and a t o t a l of 274,000,000 a c r e s w i t h i n reach of today's c a p a b i l i t y . Let us now look a t the s h o r t - t e r m e x t e n s i o n s t o e x i s t i n g c a p a b i l i t y . I n t h i s context, we mean t h a t over t h e n e x t four or five-year period given exi s t i n g R&D programs and o p e r a t i o n a l p l a n s, the a d d i t i o n a l c a p a b i l i t y t h a t w i l l ensue w i l l be a function of these c u r r e n t e f f o r t s . What w i l l happen beyond t h a t point is q u i t e another matter, however, since new programs w i l l be required and the success of e x i s t i n g programs w i l l have to be demonstrated. Figure 52 summarizes the c a p a b i l i t y p r o j e c t i o n of the system previously discussed. The c a p a b i l i t y t o d r i l l , t e s t and evaluate from a f l o a t i n g v e s s e l i n 1500 f e e t of water has been demonstrated. The SEDCO 445 has the c a p a b i l i t y t o d r i l l i n 2000 f e e t of water, and the design allows f o r extension to considerably g r e a t e r depths. Also, t h e r e a r e s e v e r a l e x i s t i n g r i g s i n a d d i t i o n to some of those under c o n s t r u c t i o n t h a t could be modified t o d r i l l i n up to 3000 f e e t of water i n one t o two years from now. It is, t h e r e f o r e , reasonable t h a t routine d r i l l i n g operations could be c a r r i e d out i n 3000 f e e t of water i n the '75 to '76 period. The water depth c a p a b i l i t y f o r wet t r e e completions is d i r e c t l y t i e d to the d r i l l i n g c a p a b i l i t y and c u r r e n t l y stands a t about 1500 f e e t . To date approximately 75 UWC's have been i n s t a l l e d i n water depths ranging from 50 t o 375 f e et . The technology required f o r the wet t r e e completions is n o t v e r y sens i t i v e to water depth and is, t h e r e f o r e , expected t o be extended i n t h e n e a r term to 3000 f e e t . The main c o n t r o l l i n g f a c t o r w i l l be the flowline connecting system and the hardware f o r i n s t a l l i n g t h e f l o w l i n e s , which w i l l be undergoing continual evolution as deepwater experience is gained. Current industry programs w i l l probably r e s u l t i n a d d i t i o n a l underwater completions over t h e n e x t few years and should provide the experience to develop a very r e l i a b l e and economically sounddeepwater wet t r e e completion system. The One-Atmosphere Chamber Wellhead System which was i n s t a l l e d by Lockheed Petroleum Services f o r S h e l l O i l Company recently i n its Main Pass 290 F i e l d has demonstrated the c a p a b i l i t y of t h i s completion system i n 375 f e e t of water. The diving capsule p a r t of t h i s system is r a t e d for 1200-foot water depth and t h i s , t h e r e f o r e , is considered the depth c a p a b i l i t y of t h i s system a t present. It is f o r e c a s t t h a t through design modification t h i s system's depth c a p a b i l i t y can be extended to 3000 f e e t . R&D work on underwater manifolding and production systems is c u r r e n t l y being c a r r i e d out and e i t h e r t h i s system or other systems such as f l o a t i n g production platforms could be a v a i l a b l e four to f i v e years from now given the r i g h t economic i n c e n t i v e s . Therefore, I think t h a t our short-term c a p a b i l i t y extension can provide the technology t o permit complete systems t o be i n s t a l l e d i n 3000 f e e t of water. Figure 53 i l l u s t r a t e s the a d d i t i o n a l e f f e c t of t h i s c a p a b i l i t y . On the margins of the conterminous U.S. plus the Alaska P a c i f i c Margin as i l l u s t r a t e d by the blue areas t h i s means the addition of about 103,000,000 acres. For the Alaskan portion (the red a r e a s ) , 32,000,000 acres is added. Regarding the Alaskan portion, it is recognized by t h e a u t h o r t h a t a g r e a t d e a l of e f f o r t is going i n t o Arctic Research t o develop the technology t o carry o u t e x p l o r a t i o n and production a c t i v i t y i n t h i s area. The recent announcement by Global Marine of the construction of an i c e breaking d r i l l s h i p is i n d i c a t i v e of the i n t e r e s t i n t h i s area. It is, therefore, poss i b l e t h a t the f i g u r e s quoted here f o r Alaska are conservative. However, an attempt has been made to include only t h a t a d d i t i o n a l area which has a reasonable c e r t a i n t y of being w i t h i n t h e c a p a b i l i t i e s purported. As an example of t h i s , only one-half of the B r i s t o l Bay area is included even though almost the e n t i r e area is i n l e s s than 600 f e e t of water. Although platforms and underwater systems i n combination could extend the basic platform depth c a p a b i l i t y (200 f e et ) the f a c t t h a t much of the area is 200 to 300 miles from shore w i l l cause s i g n i f i c a n t problems of access and t r a n s p o r t a t i o n . Figure 54 summarizes the t o t a l a r e a s w i t h i n reach of today's c a p a b i l i t y and t h a t a d d i t i o n a l area which is within reach of t h e s h o r t - t e r m extensions of today's c a p a b i l i t y . I n summary, approximately 274,000,000 acres (31% o f t h e t o t a l ) of t h e c o n t i n e n t a l margins of the U.S. a r e within reach of today's t e c h - nological c a p a b i l i t y and approximately 409,000,000 (46% of the t o t a l ) is within reach of our near-term c a p a b i l i t y . The r e a l question is what these 409,000,000 acres hold f o r us i n the way of petroleum r e s e r v e s . Mother Nature, i n the past, while yielding up bountif u l petroleum resources, has tended t o put very large portions i n r e l a t i v e l y few s p o t s , and no one w i l l r e a l l y know i f t h i s acreage contains s i g n i f i c a n t reserves u n t i l i t has been t e s t e d by the d r i l l . Our success or f a i l u r e i n so doing w i l l influence g r e a t l y the importance of and the r a t e a t which we pursue those portions of the c o n t i n e n t a l margins not presently within our c a p a b i l i t y . Therefore, we should pursue with a l l vigor and haste those areas t h a t are within our present- and near-term technological grasp and, a t the same time, we must continue to provide the necessary R&D programs t h a t w i l l i n s u r e t h e a b i l i t y to develop f e a s i b l e solutions f o r those areas t h a t a r e not presently within our c a p a b i l i t y . Some Implications of Accelerated Offshore Leasing Technological c a p a b i l i t y is one thing; however, there are several other important considerations t h a t must be examined. The economic aspect is one which looms i n a l l our minds a s perhaps even more formidable than technology and although not discussed i n t h i s paper, I c e r t a i n l y do not want to minimize that aspect. I would, however, like to discuss some of the considerations regarding industry response to hopefully accelerated offshore leasing. I n the report "U.S. Energy Outlook1' a preprint of which was released in December 1972 by the National Petroleum Council:,, several cases of accelerated domes t i c o i l and gas d r i l l i n g a c t i v i t y were examined (Chapter IV). The highest growth r a t e hypothesized i n that report was a 7.5 percent annual increase i n exploratory d r i l l i n g footage (labeled Case I ) . This increase in d r i l l i n g a c t i v i t y would achieve a level of a c t i v i t y i n 1985 about equal to the post World War I1 peak a c t i v i t y achieved i n 1955. Figure 55 i l l u s t r a t e s , in summary, the impact of t h i s case on the domestic energy and petroleum imports. The dotted l i n e s correspond to the same a c t i v i t y level as Case I but a lower finding r a t e . I think these two curves can be summarized as follows. By 1985, assuming the increased a c t i - v i t y becomes a r e a l i t y , the best we can do (high finding r a t e ) i s to achieve a level of dependence on foreign sources about equal to our c u r r e n t l e v e l . It i s possible, however, (low finding rate) that we would be able to only a r r e s t any further dependence beyond 1975. Although the NPC report does not give a completely detailed breakdown of the t o t a l offshore portion of the a c t i v i t y , enough d e t a i l i s given by region to estimate that which may be a t t r i b u t a b l e t o the offshore. Figure 56 was derived by applying the regional allocations for o i l and gas d r i l l i n g to the t o t a l o i l and gas d r i l l i n g f o r Case I. These r e s u l t s include only California, Gulf Coast and A t l a n t i c offshore (most of that which i s hypothesized), and for o i l d r i l l i n g , the regional allocations given for 'exploratory footage are assumed to apply to t o t a l o i l d r i l l i n g footage. Under these assumptions, the t o t a l offshore d r i l l i n g i n 1975 would be about 18M f e e t per year increasing to about 41M f e e t per year by 1985. Assuming that a l l of the exploratory footage (approximately 1/3 of the t o t a l footage) would be d r i l l e d from mobile platforms and the other 2/3 would be d r i l l e d from fixed platforms, Figure 57 shows the mobile r i g s which would be required to d r i l l this footage. Wells are assumed to be 10,000 f e e t and each well is assumed to take 45 days including t r a v e l , e t c . t o d r i l l. In 1975 approximately 74 mobile rigs would be required and this would increase by about 9 to 10 r i g s per year reaching a level of about 166 r i g s by 1985. For comparison, the existing number of mobile rigs (domestic) are shown a t the l e f t i n the figure. The annual increase of 9 to 10 r i g s per year represents about 20 to 25 percent of the present world r i g building capability of 40 to 50 r i g s per year. Figure 58 shows the number of 25 well fixed-platforms required again assuming 10,000-foot wells. S t e e l tonnages a r e also shown for 200,300, and 400-foot water depth s t r u c t u r e s . Although the water depth d i s t r i b u t i o n i s not known, i t i s reasonable that the tonnages would c e r t a i n l y f a l l somewhere i n t h i srange, perhaps averaging near the 300-foot l i n e . By 1985, the tonnage would increase to about 500,000 to 950,000 tons per year or a 3 to 6 fold increase over existing Gulf Coast capability of approximately 150,000 to 200,000 tons per year. This corresponds to an annual growth r a t e (over the next 12 years) of from 9.5 to 15 percent. Although no doubt additional f a c i l i t i e s would come into play during t h i s period (West Coast, East Coast, e t c .) , the r a t e of growth and the mobilization of additional f a c i l i t i e s would require s i g n i f i c a n t long range planning and a great amount of assurance to a t t r a c t investment c a p i t a l and trained manpower.

The two, examples above (mobile r i g s and fixed platforms) represent but a fraction of the t o t a l e f f o r t required to support a perhaps rather nominal increase i n present a c t i v i t y (NPC Case I ) . There are l i t e r a l l y hundreds of supporting i n d u s t r i e s who must be attuned to any escalating e f f o r t and who will also require firm assurance that a market for t h e i r goods and services w i l l be available.

Since the early beginning of offshore d r i l l i n g and production a c t i v i t i e s , the technology to provide the necessary safe and r e l i a b l e systems has very adequately kept pace with our economic needs. Existing technology related to a l l aspects of these a c t i v i t i e s has reached a high level of competence through the i n t e r - r e l a t e d e f f o r t s of research and development, engineering, and p r a c t i c a l experience. The technological "muscle", capable of working is almost one-half of the nation's continental margins, now stands ready to be flexed to help provide v i t a l domestic petroleum resources to meet our growing energy needs.

The author acknowledges the many technical reports by those i n the industry, the-academic community and the government who have made valuable contributions to the development of offshore technology and the many others who have supplied the equipment and services to support t h i s new technology. The e f f o r t s of I . B . Boaz, C.A. S e l l a r s , and G .A. S t e r l i n g i n preparing t h i s paper are g r a t e f u l l y acknowledged, and the author thanks Shell O i l Company for permission to make t h i s presentation.

1. 1971, Future Petroleum Provinces of the United States - Their Geology and Potential: Memoir 15, Volumes I & 11, AAPG, Tulsa, Oklahoma.

2. December 1972, U.S . Energy Outlook: Preprint National Petroleum Council.

3. Nelson, T.W. and Burk, C .A . , 1966, Petroleum Resources of the Continental Margins of the United States .

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