OTC Abstract. The Arctic Circle

Transcription

1 OTC Deepwater Drilling for Arctic Oil and Gas Resources Development: A Conceptual Study in the Beaufort Sea N. Pilisi, Blade Energy Partners; M. Maes, Blade Energy Partners; D.B. Lewis, Blade Energy Partners Copyright 2011, Offshore Technology Conference This paper was prepared for presentation at the Arctic Technology Conference held in Houston, Texas, USA, 7 9 February This paper was selected for presentation by an ATC program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Offshore Technology Conference and are subject to correction by the author(s). The material does not necessarily reflect any position of the Offshore Technology Conference, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Offshore Technology Conference is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of OTC copyright. Abstract Surveys from the U.S.G.S, notably, have recently re-assessed the Arctic Circle and its deepest parts. Geology-based probabilistic analyses have found that significant oil and natural gas reserves, about 25% of the world s undiscovered resources, may be held in the deep Arctic Alaska (Bird, 2008; Houseknecht et al, 2010). Such studies are of the utmost interest for developed and emerging countries to help them meeting their growing demand in fossil fuels. As of today, the bulk of investigations, projects and technical papers concerning drilling for arctic oil and natural gas resources, have concerned the onshore hydrocarbon accumulations or the near shore deposits (OTA, 1985; Bercha, 1984; Matskevitch 2006; MMS, 2008). However, when trying to access the arctic deeper waters, only a few structures are available today to drill in these polar environments. Offshore operations in the Arctic Ocean are essentially impacted by extremely cold weather temperatures yielding the presence of sea ice, icebergs, floes and long period of darkness. Nevertheless, deepwater drilling and production in the Arctic Ocean provides an attractive but extremely ambitious challenge for our industry. Because the U.S. Beaufort Sea has an average water depth of 3,240 ft, deepwater drilling provides an interesting and innovative option to develop enormous reserves of oil and natural gas. This paper presents a conceptual study for exploratory and development wells in the harsh deepwater arctic environment of the U.S. Beaufort Sea by using a modified and winterized drill-ship with ice strengthened material or an icebreaker converted into a drilling vessel. In addition, ice management is discussed, considering a fleet of at least two icebreaker vessels to guaranty station keeping in first year sea ice and multi-year sea ice environments in order to conduct year-round operations with the floater. Also, the drilling and production phases will be discussed even in presence of icebergs or large ice floes. Finally, the paper briefly covers environmental regulations and economics. The main goal of this study is to help the oil and gas industry breaking the last barrier in exploration drilling and production by proposing structures and facilities that will enable to operate year-round in both open water and permanently ice-covered waters of the Arctic Circle. The Arctic Circle The Arctic Circle is a vast region around the North Pole which emcompasses notably the northern parts of Europe (Greenland, Iceland and Scandinavia), Asia (Siberia and the far east of Russia), North America (Alaska and Canada) and the Arctic Ocean as illustrated in Figure 1. With a size equivalent to three times the size of the U.S., most of the Arctic is covered by shallow and deep oceanic waters. In addition, most of the Arctic Ocean is deeper than 2,000 feet with average ice thickness ranging between 3 and 30 feet depending on the latitude. However, one phenomenon that has been observed in recent years is that multi-year ice marking the polar seas region has been thinning and in some case even retreating, leaving place to a short open-water season. Furthermore, recent studies from the Energy Information Administration (2009) have

2 2 [22092] estimated that large undiscovered oil and gas resources occur offshore in the arctic Alaska region and that, particularly the U.S. Beaufort Sea, may hold the largest undiscovered oil deposits. Figure 1. Bathymetric Map of the Arctic Circle and the Beaufort Sea (Modified from Jakobsson et al., 2008) Shallow Water Exploration Exploration activity in the sub-arctic Alaskan region began in the 1940s. As of today, over 5,000 wells have been drilled in Alaska. However, the major part of these wells was drilled onshore in the Prudhoe Bay region. The first offshore development of hydrocarbons dates back from 1963 in the Cook Inlet of Alaska. Then, followed several drilling campaigns using platform structures, bottom founded structures and also man-made artificial islands made of gravel, sand or more recently ice (Matskevitch, 2006; MMS, 2008). These structures operated in water depths less than 100 feet. As of 2010, over 30 wells have been drilled in the U.S. Beaufort Sea near the Alaskan shore (Masterson et al, 1991). Numerous discoveries of oil and gas deposits near shore have given confidence to the industry in exploring deeper and northern areas of the Beaufort Sea (Quinn, 1999). In addition, a great body of knowledge on the topic of drilling and producing in onshore and shallow water areas has been accumulated for the last four decades (Lucas et al, 2008). Finally, drilling and production operations in the offshore arctic regions require that procedures used onshore and offshore in less severe environment must be adapted in order to overcome the hostile weather and the harsh environment. Deepwater Exploration The deepest parts of the Arctic Ocean that are covered with thick multi-year ice are estimated to hold large reserves of oil and natural gas that could account for up to 25% of the world s undiscovered hydrocarbons. Therefore, there is a renewed interest for accessing these arctic reserves. However, more severe conditions such as deeper waters, lower temperatures, and thicker ice sheets increase significantly petroleum and structural engineer challenges. In the offshore oil and gas industry, deepwater is often defined as water depths in excess of 2,000 feet and ultra-deepwater starts when water depths are greater than 5,000 feet. For arctic waters, the frontier between shallow, near costal waters, and deepwater areas can be defined as water greater than 1,000 feet since, as of today, no drilling and production facilities have operated and produced in these water depths.

3 [22092] 3 The Beaufort Sea The Beaufort Sea is located on the edge of the Arctic Ocean and north of the state of Alaska and Canada. With an average depth of over 3,000 feet and its deepest part being greater than 15,000 feet, the Beaufort Sea has multi-year solid ice in its central and northern parts. The southern part, close to the U.S. and Canadian shores, has an icepack that opens during the summer season. In the Beaufort Sea, like in other arctic regions, metocean and ice conditions follow a great variability between seasons and from one year to another. However, an important body of experience and data have been accumulated that can help predicting environmental conditions. The main environmental data that are needed for the selection of deepwater drilling and production facilities are summarized in the next paragraph (Mahoney et al, 2005; MMS, 2008; ISO 19906, 2009). The ocean surface flow follows a clockwise pattern due to the Beaufort Gyre. The ice environment can be divided into three main bodies with an average speed of 0.26 feet per second. The landfast ice which forms in water depths up to 65 feet is comprised mainly of first-year ice with thickness equals to 6 feet even though multi-year ice may be present during the freeze-up season. The transitional zone extending between the landfast ice and the polar pack ice is composed mainly of firstyear ice and also second-year and multi-year ice floes. The polar ice pack is comprised of multi-year ice with an average thickness of 15 feet. Natural ice islands with surfaces up to 270 mi 2 and icebergs with mass geater than 10 million tonnes can circulate in the Beaufort Sea and are a major threat to the drilling structures. Average air temperature ranges between -50 F and 70 F, wind speed can be as high as 70 feet per second with an average direction changing from northeast in the summer season to west in the winter season. Figure 2 presents sea ice types in the Beaufort Sea. Landfast usually starts breaking in early June and the transitional zone break-up can be as late as the first week of September, leaving only a few weeks of openwater before freeze-up (Natural Resources Canada, 2010). In addition, deepwater areas of the Beaufort Sea are underlain by very competent soils (greater than 2 ksf) which provide ideal foundations for the structural pipes and subsea equipements. Sub-seabed permafrost which is a layer of offshore sediments that have remained below 32 F for two years and can be present on continental shelves do not have to be considered in deepwater operations because evidences of presence of offshore permafrost have not been found in water depths greater than 100 feet (Miller et al, 1980; Osterkamp, 2001). Beaufort Sea Beaufort Sea Figure 2. Sea Ice Types in the Beaufort Sea (Modified from Natural Resources Canada, 2010) Station Keeping and Ice Management In order to conduct oil and gas exploration and production activities in the deepwater arctic seas, several environmental factors that can greatly affect the operations must be considered and numerous challenges must be overcome (Walsh et al, 2004). Those are mainly sea ice, ridges and icebergs, fog, gusty winds, long periods of darkness and very cold temperatures. Thus, a fundamental objective is the ability and necessity to maintain position over the drill site or production site to recover oil and gas in harsh weather with temperatures near or below 32 F and waters covered with ice floes and icebergs floating towards the drilling vessel or the production facilities. Station keeping during drilling operations can be performed in three different configurations: operational drilling mode, non operational with marine drilling riser connected to the blow-out

4 4 [22092] preventer (BOP) or riser disconnected from the BOP. When producing from the reservoir, also, three modes can be distinguished: operational production mode, non operational with production risers connected to the turret and with the production vessel, or production vessel disconnected from the turret. Therefore, in order to maintain position in this harsh ice environment, ice management is commonly used as an efficient way of controlling ice floes and icebergs drifting in the vicinity, usually a mile radius, of the offshore drilling or production structure and allowing to extend, in some cases, the drilling season to year-round operations (Keener et al, 2009). The ice management operating procedures follow an active approach (ISO 19906, 2009) similar to the scientific drilling expedition 302 conducted by the International Ocean Drilling Program in 2004 (Backman et al, 2006). Figure 3 depicts the overall ice management system that can be deployed for drilling and production campaigns in the arctic regions. First, onboard one or two icebreakers (depending on the severity of ice conditions and the size of the project) navigating upstream at a distance ranging between 0.5 and 2 miles upstream from the drill site, several technologies that can survey regional and local ice and weather conditions are used to monitor ice movements. These technologies include notably visual observations, helicopter reconnaissances, airborne radar and satellite imageries (Backman, 2009). Once the ice hazards are detected, the first icebreaker can break the large ice floes in smaller pieces. Then, the second, smaller and more mobile icebreaker breaks the smaller ice floes that flow towards the drilling structure. In addition, one or several smaller vessels using synthetic lines can be used for open sea season when towing icebergs or ice ridges is needed (Crocker et al, 1998). Therefore, this global ice management configuration should enable the dynamically positioned drilling vessel (having at least four thrusters: two in the bow and two in the stern) to keep a fixed position and to conduct exploratory or development drilling but also production operations minimizing the risk due to ice floes or icebergs. Finally, in the case where ice conditions would become too difficult to manage for the icebreaker fleet and towing boats, the drilling riser would be disconnected, the drill pipe retrieved (tripping pipe speed 1,000 feet per hour) and the drilling vessel would move away from the drilling site for a few hours before coming back on position and resuming operations. Furthermore, station keeping operational window needs to be determined, depending on site environmental conditions; but is expected to be less than a few percent of water depth before disconnection of the marine drilling riser. In addition, to ensure that the vessel will stay in position even in the most difficult ice and weather conditions, recent technologies such as azimuth propulsion should be implemented onboard the winterized drilling structure. Figure 3. Ice Management Solution for the Beaufort Sea

5 [22092] 5 Structures for Exploratory and Development Drilling The selection of a drilling structure for operations in the arctic waters must take into account an exhaustive number of parameters to ensure the success of an exploratory or a development drilling campaign (Chakrabarti, 2005). The essential criteria to be considered are water depth (relatively shallow or deep), metocean conditions (waves, current, wind) and operating period (seasonal or year-round). Then, the ice conditions are to be treated with great care. Thus, the design engineer needs to collect site specific ice data such as main ice features (ridges, landfast ice, pack ice, icebergs, ice floes) and ice drift velocities (MMS, 2008; ISO 19906, 2009). In response to these environmental conditions, double-ended hull, ice management systems, station-keeping technologies, drilling components such as riser systems and subsea equipments, coldweather materials must be selected to ensure the structural integrity of the drilling vessel (API 2N, 2007; ABS, 2010). This paper discussion considers an active drilling structure approach that can move off location if extreme ice conditions are to be experienced by the vessel. These structures must be, as well, associated with an active ice management program as shown in Figure 3. For deepwater areas, passive designs that can withstand all environmental conditions such as fixed structures that would need to resist ice sheets and ridge loads notably are not technically and economically feasible. In Figure 4, five main types of drilling structures for deepwater arctic environments are illustrated: three existing drilling vessels and two concepts. Then, the main advantages and limitations of the five drilling structures for conducting successful deepwater drilling operations in the arctic regions are reviewed and discussed. Figure 4. Drilling Structures for Drilling Operations in the U.S. Beaufort Sea In the non arctic deepwater industry, semi-submersible drilling rigs (structure type N 2 in Figure 4) are often the best suited option when drilling rough weather environments (in the Gulf of Mexico, for instance) because of their better stability in pitch, roll and heave as compared to drill-ships. In addition, a recent trend seems to tend towards the construction of larger 6 th generation drilling vessels (structure type N 3 in Figure 4) than the current 5 th generation drilling rigs that are currently being utilized to drill exploration and development wells, complete and perform work-over activities on oil and gas wells. However, drill-ships not only have a larger deck load capacity but are more effective in regions where waters with ice floes

6 6 [22092] and ridges presence (structure type N 1 in Figure 4). The larger the vessel deck area is, the more it reduces re-supply costs (rental tools, pipe, drilling mud, cement and spare parts). This feature is very important during the winter period because the distance from the closest dock facility can be large. For instance, this has recently been illustrated with the deployment of the ice-class Discoverer drill-ship in the offshore continental shelves of the U.S. Beaufort Sea which has been preferred over the Kulluk submersible drilling platform to perform exploration and appraisal drilling campaigns. Therefore, the drilling structure needs to be chosen as a self sufficient vessel capable of carrying a large amount of fuel, equipment, drilling fluids, spare parts and with a double ice strengthened hull (ABS, 2010). The main working areas of the derrick, moon pool, pipe racks, and drill floor need to be fully enclosed with an ambient temperature maintained around 70 F for the vessel workers because several studies have shown that low temperatures could reduce significantly the performance and vigilance of the drilling crew. Also, thrusters or propellers must be protected from ice chunk impacts. Other concepts are currently under development such as non ship shaped circular vessels that could perform drilling and production operations but also could store the oil and gas produced (Srinivasan et al, 2008). The design of these circular vessels shows a large deck and storage capacity, thus providing a greater inertia and momentum to break ice sheets (structure type N 4 in Figure 4). Besides, these circular vessels design could allow operations in both conventional and ice covered deepwater regions and therefore provide a more economic alternative to the operators. Additionally, semi-rigid floater concepts have been developed for seasonal and year-round operations in water depths up to 1,500 feet and even with firstyear ice presence (structure type N 5 in Figure 4). These semi rigid floaters are also composed of a circular hull. However, several groups of cables and anchors, between three and six, are needed to anchor to the drilling vessel (MMS, 2008). Furthermore, another promising concept is the deployment of a relatively small unmanned drilling rig sitting on the seabed in deepwater environments and which is connected to the surface with wireline to transmit power and communication from a surface vessel (Raunholt et al, 2010). Moreover, structural designs must ensure that the drilling and production structures are able to endure extremely cold weather conditions and withstand ice loading (Allan et al, 2009). Thus, often, ice loads are the most important loads that can be experienced by offshore structures; they are often governing the design of the drilling and production facilities in arctic waters and in the Beaufort Sea (Basu et al, 2009). Therefore, it is of the utmost importance to understand the global response of structures exposed to ice loading. Small scale tests have proven to overestimate ice loads. Thus, engineers need to rely on full-scale field data and measurements. First-year ice loading in the Beaufort Sea, mainly, and also multi-year ice impact data have been collected in Greenland and northern Canada constituting the current knowledge in the offshore arctic industry. In addition, the new ISO standard on arctic offshore structures provides great details on the design needed to withstand ice actions. Deepwater drilling in the Beaufort Sea may occur in two different ice type regions. First, the region between the fast ice and pack ice where open-water is present starting July. In this transitional zone, the deepwater sites are covered with 8/10 firstyear ice, ridges, icebergs. In addition, there is a second region in the northern part of the sea where polar pack ice is present and where once freeze-up occurs at the beginning of the long winter season, pack ice thinkens and ice speed is relatively slow. Also, in the Beaufort Sea, shallow water drilling campaign have provided valuable data such as drilling time. It appears that an exploratory well takes an average of five months from spud to rig release (Matskevitch, 2006; MMS, 2008). However, when drilling deeper waters, year-round rig capability is needed to continue drilling in both the summer and winter seasons. Thus, in order to conduct both exploratory and development drilling operations in these two ice environment zones, an icebreaker converted into a drill-ship (equipped with a moon pool and a drilling rig notably) or a built for purpose drill-ship strengthened for navigation and operation in ice covered waters (POLAR or ICEBREAKER class according to DNV, 2007 and American Bureau of Shipping standards, 2010) are selected as the best option to conduct drilling programs in the Beaufort Sea as illustrated in Figure 5.

7 [22092] 7 Figure 5. Converted or Built-for-Purpose Icebreaker to Conduct Year-Round Drilling Activities The generic vessel characteristics are listed in Table 1. Besides, since materials are sensitives to brittle fracture caused by arctic temperatures that can be as low as -60 F, arctic grade steels need to be specified for all load bearing structures and parts. In addition, special lubricants and elastomeres need to be employed in the design of the different mechanical parts (DNV, 2007). Table 1. Icebreaker Modified Drilling Vessel Specifications DRILLING VESSEL CHARACTERISTICS Ice Class (DNV or ABS) POLAR or ICEBREAKER Length (ft) 500 Width (ft) 100 Depth (ft) 50 Water Depth (ft) 1,000 to 5,000 Drilling Depth (ft) 30,000 Moonpool Length (ft) 50 Moonpool Width (ft) 35 Deck Capacity (tons) 50,000 Derrick (kips) 1,500 Riser Tension (kips) 2,000 Mud Pit (bbl) 8,000 The selection and evaluation of a drilling vessel for drilling activities is only the first major step when trying to develop the deepwater resources lying under the seabed of the Arctic Circle. In order to produce hydrocarbons, specific structures and equipments are needed to put the wells drilled on production and bring the crude oil and natural gas to markets. Structures for Production Operations Moreover, the different structural options for oil and gas production from deepwater areas of the Beaufort Sea are presented and discussed. Like drilling vessels, the floating production storage and offloading units (FPSO) must be associated with the same active ice management program as described in Figure 3. Similarly to drilling structures, production facilities with passive designs that can withstand all environmental conditions are not considered in our study. Thus, only two main types of

8 8 [22092] FPSO structures for deepwater arctic environments are illustrated. Figure 6 shows one existing FPSO vessel (structure type N 1 in Figure 6) and one FPSO conceptual design for production in the Beaufort Sea (structure type N 2 in Figure 6). In the Beaufort Sea deepwater regions, year-round production capacity and flexibility is required. Therefore, oil and gas production needs to take place in both the open-water summer season and the harsh multi-year ice winter seasons. Also, the FPSO facility design demands to be able to operate in the two ice regions of the Beaufort Sea: the transitional zone and the pack-ice zone. Thus, an ICEBREAKER or POLAR class FPSO is selected as the best option to conduct production operations in the Beaufort Sea as illustrated in Figure 6. In addition, several flexible production risers with diameters greater than 5 inches will be used to carry the oil and gas produced from the subsea wellhead to the turret located between midship section and the bow. Then, the turret connects flowlines to the FPSO vessel hydrocarbon tanks. Since, in deep water, the wellhead is located well below the maximum keel depth, averaging 82 feet in the Beaufort Sea; glory holes are not considered to protect the subsea systems from ice ridge keels and are laid on the seabed similarly to other deepwater production operations (Brazil, Gulf of Mexico, West Africa). Figure 6. FPSO Structures for Production Operations in the U.S. Beaufort Sea The main FPSO characteristics are listed in Table 2. The FPSO will have a production storage capacity in excess of 100,000 BBOE per day. Similarly to the drilling structures, arctic grade steels need to be specified for all load bearing structures and parts of the FPSO.

9 [22092] 9 Table 2. FPSO Vessel Specifications FPSO VESSEL CHARACTERISTICS Ice Class (DNV or ABS) POLAR or ICEBREAKER Length (ft) > 800 Width (ft) 130 Depth (ft) > 60 Water Depth (ft) 1,000 to 5,000 Total Wells > 10 Max Oil Production (BO/day) > 100,000 Gas Processing (Mscf/day) > 100,000 Storage Capacity (Barrels) 2,000,000 Production Risers > 3 Offloading System Crane, Mooring Line and Hose Offloading Capacity (Barrels/hr) > 50,000 Besides, producing from arctic wells can, also, be a challenging process. Thus, special completion equipments similar to conventional deepwater wells like sub-surface safety valves, well control and chemical injection systems must be put into place to insure proper flow of the produced hydrocarbons. In addition, care must be taken in the event of gas hydrates or waxes forming during circulation of the produced fluids. Indeed, both drilling and production operations can be affected by gas hydrates formations. Hydrates are crystalline compounds forming at high pressures and low temperatures. Molecules of gas such as methane, nitrogen or CO 2 can get trapped in a cage-like called crystal lattice formed by molecules of H 2 O (Makogon et al, 2004). These ice-like structures can either exist in sub-seabed sediments or form while circulating drilling fluids. They are very sensitive to change in pressure and temperature and can dissociate and release gas. To avoid hydrates formation, design temperatures (greater than 150 F) and pressures (greater than 5,000 psi) are chosen well above the formation envelop because of expected shut-downs than can last several hours (Roaditer et al, 1987). Finally, it seems that for the Beaufort Sea remote oil and gas fields, a marine terminal consisting in direct shipment from offshore FPSO to icebreaking tankers is the best technical and economical solution. Environmental Considerations and Regulations Arctic regions are very sensitive areas that require specific regulations to perform any industrial activities. The U.S. Environmental Protection Agency (EPA) regulates pollution programs and controls all the waste materials resulting from the activities of drilling and production of hydrocarbons in the U.S. Beaufort Sea. The waste materials are diverse such as water based drilling mud, drill cuttings, produced water and sand, chemical products and domestic waste, and must be conveyed to shore for disposal (Schumacher et al, 1991). If offshore discharges were to be planned, the Bureau of Ocean Energy Management (BOEMRE) would also regulate the discharge activities. In the case of operations in the deepwater areas of the Beaufort Sea with first year and multi-year ice presence, the waste materials would be shipped back to shore. In the case of an oil spill, several solutions can be used. During summer season, in open water conditions, mechanical containment and skimmers can be used. During the re-freezing period, the presence of ice floes increases the difficulty of proper cleaning and therefore in-situ burning would be chosen as the most efficient remede for clean-up (Warner et al, 1972; Ross et al, 1998; MMS, 2003; Dickins et al, 2008). However, it is important to note that less than 20 wells have experienced blowouts in Alaska over the last decades which indicate that this arctic region is not risker than other petroleum provinces of the world (Nelson, 2008) and; that if conducted with great care, deepwater drilling and production operations should have a very low risk and impact on the arctic environment (Izon et al, 2007). In addition, it has been simulated that any incident or spill that could happen in the U.S. Beaufort Sea would soon propagate to neighbouring seas and reach Canadian waters due ocean currents. Therefore, American and Canadian regulatory agencies must work together to develop their deepwater oil and gas reserves in the Arctic Circle. Finally, adapting and enhancing existing technologies and procedures to address deepwater and cold-weather hazards should reduce the technical and environmental risks as compared to the implementation of new designs and technologies for the drilling and production structures (structure type N 1 in Figure 4 and structure type N 1 Figure 6).

10 10 [22092] Economics Discovering and developing oil and gas deposits from the arctic deepwater regions is a highly difficult and expensive venture. According to a recent report published in Europe on research infrastructures for Polar Regions, an icebreaker drilling vessel capable of operating in deep sea such as the one that has been described in this paper is expected to cost over $500 million. In addition, operating expenses for the drilling program, the ice management procedures, the production facilities and transport to market drive the total cost up to several billion dollars. Therefore, it seems that only the world s largest operating companies have the financial and technical strength to embark upon such challenging projects. However, if associated in joint-ventures, oil and gas companies could unlock a very large amount of yet unproved oil and gas reserves and, thus satisfy the world s energy growing demand. Finally, the recent two-year high in oil price topping the $90 per barrel mark in early December 2010 may be another driver for oil and gas companies and encourage them to consider an exploratory drilling campaign in the deepwater Arctic Circle (either in the North American part, in the European part or in the Russian part) in the near future. Conclusions New recent assessments of the deepwater Arctic Circle (EIA, 2009; U.S.G.S., 2010) have revived the interest and need to break the remaining barrier in oil and gas exploration drilling. However, for the past decades, the installation of floating systems in the U.S. Beaufort Sea, in particular, in shallow arctic waters with water depths not exceeding 100 feet, has been already a significant technical challenge. Therefore, operating companies are currently on hold on the technical side before being able to launch exploratory deepwater drilling campaigns. In this paper, the current best drilling and production structure options have been described and proposed to help finding, developing and producing from deepwater oil and gas deposits in the Beaufort Sea and its U.S. part notably. Since, there are different ice type zones in the Beaufort Sea and, that the drilling structure has to be capable of conducting both exploratory and development drilling operations in distinct deepwater Beaufort Sea areas, an icebreaker retro-fitted into a drill-ship or a built for purpose drilling vessel designed for navigation and operation in ice covered waters seems to be the best solution for drilling in harsh deepwater regions. Thus, the other commonly used solutions for conventional deepwater drilling such as tension leg platforms, semi-submersible and drill-ship vessels have been rejected. Similarly, an icebreaker class of floating production storage and offloading unit (FPSO) facility that meets the demand of being able to produce oil and gas in both the open-water summer season and the multi-year ice winter seasons in the deepwater Beaufort Sea has been described. Besides, emerging drilling and production concepts such as non ship-shaped circular structures that could perform drilling and production activities may decrease the costs, reduce the technical challenges and simplify the overall process. In addition, to complement the selection of drilling and production structures, an active ice management approach has been proposed and illustrated. Thus, by using one or more icebreakers, navigating upstream the drill or production site that are equipped with the latest ice and meteorological survey technologies and several small boats using synthetic lines for icebergs and ice ridges towing, drilling and production operations in severe ice conditions can be conducted. Finally, the offshore regulations and environmental considerations in the arctic waters have been briefly covered. Also, the economics involved when pursuing such complex, challenging and expensive ventures have been discussed. In conclusion, all the technologies and concepts that have been described and discussed in this paper can be adapted to other deepwater arctic regions such as offshore Scandinavia, Greenland and Siberia (Cooper, 2005; Finn, 2009). For instance, in Greenland, petroleum exploration licenses have been recently awarded for exploratory drilling in deepwater depths up to 5,000 feet. Ultimately, this work may help assisting operators in planning future arctic deepwater installations and operations. Acknowledgements The authors thank Blade Energy Partners for permission to write and publish this paper and the OTC for inviting us to present during the first ATC event.

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