This paper describes the results of the feasibility study of an arcticoffshore platform concept sponsored by ConocoPhillips. This concept consists ofa Conical Piled Monopod (CPM) platform, shown in Figure 1, assisted by an IceWorthy Jack-up rig, Gemini, to drill development wells in Multi Year iceconditions as illustrated in Figures 2 and 3. The Gemini design is beingjointly developed by ConocoPhillips and Keppel Offshore and Marine TechnologyCentre Pte Ltd based in Houston. Gemini is equipped with two drill rigsthat can simultaneously or individually cantilever above the well slots locatedon the deck of the CPM. The key benefit of Gemini lies in extending thedrilling season from a few months during ice free season to several monthsbeyond the ice free period.
The study was carried out at Granherne Limited under ConocoPhillips'supervision between March 2010 and February 2011. A topsides operatingload of 5,000 tonnes was assumed, instead of 70,000 tonnes (or more)corresponding to a two drill rig stand alone drilling and production CPM. Thefeasibility of a stand alone drilling and production CPM was presented inanother paper at Icetech12 in September 2012.
The study concludes that a Gemini assisted CPM is feasible for iceconditions in the Canadian Beaufort Sea. The ice loads were calculated,in consultation with Ken Croasdale, a well known specialist in this discipline.Ice conditions assumed in this study were in accordance with ISO-19906, namely,12m thick level ice and a very rare 25m thick ice island event. No icemanagement was assumed. A Gemini assisted CPM offers a much lighter platformcompared to a standalone CPM or Gravity Based Structure.
ConocoPhillips has a patent pending on the CPM. ConocoPhillips andKeppel Offshore have patent(s) pending on the Ice Worthy Jack Up drilling rig,Gemini.
Every operation site, oil and gas drilling, shipping , pipelines and loadingfacilities, need a design basis to be properly planned. Also monitoring of theenvironment when the operation has already started is of utmost importance.This became noticed already in late 1960ies during the Manhattan voyages. Eversince ice data has been collected around various projects both in the westernand eastern Arctic. In Canada the heat was on during the Polar Gas and ArcticPilot Project in the 1970ies and 80ies. The discoveries in the Russian Arcticlaunched systematic arrangements to collect ice data in the in thePechora Sea, Barents Sea, Kara Sea, Ob Bay and offshore Sakhalin Island duringthe last 25 years. This paper describes the main features of typicalarrangements made for a successful data collection expedition, how arrangementsworked and also difficulties met during the execution of such anexpedition.
Stoupakova, A.V. (Moscow State University) | Kirykhina, T.A. (Moscow State University) | Suslova, A.A. (Moscow State University) | Kirykhina, N.M. (Moscow State University) | Sautkin, R.S. (Moscow State University) | Bordunov, S.I. (Moscow State University)
The Russian Western Arctic Basins cover the huge area including the Barentsand Kara seas, the western part of the Laptev sea and adjacent territories withsome archipelagoes and islands (Spitsbergen, Franz Josef Land, SevernayaZemlya, Novaya Zemlya, etc.). They comprise the Barents and Kara Basins, thenorthern areas of the Timan-Pechora Basin, the North West Siberia, includingYamal and Gidan peninsulas and the Yenisey-Khatanga Basin. Within the RussianWestern Arctic basins the following main tectonic elements can be identified:extensional depressions (Central-Barents, Yenisei-Khatanga, West Siberia, EastUrals) with sedimentary thickness is more than 12- 14 km; platform massiveswith average thickness of sediments of 4 - 6 km, monoclines and tectonic steps,like transition zones between extensional depressions and platform massives.Western Arctic basins are filled by mainly Palaeozoic and Mesozoic sedimentarysuccessions. In the sedimentary cover of this large region, many commonstratigraphic complexes and unconformities can be traced within Palaeozoic andMesozoic complexes that show similarity of geological conditions of theirformation. Analysis of the Russian Western Arctic basins, their structures andhydrocarbon prosepctivity shows the areas, which are favourable for hydrocarbonaccumulations. Deep depressions, as areas of long-term and stable sinking, arehighly promising zones for the accumulation of predominantly gas fields. Theyform regional gas accumulation belts, extending for thousands of kilometres,where the largest fields can be expected in the zones of their intersectionwith the major tectonic elements of another strike. Within the Barents-Karashelf, the large belt of predominantly gas accumulation extends from the northof the West Siberian province through the South Kara basin and into the BarentsSea. The second potential belt of predominantly gas accumulation may beassociated with the North Barents ultra-deep depression. On the flanks of thedepressions the sedimentary cover profile does not contain the complete set ofoil-and-gas-bearing complexes, identified in the central parts of theextensional depressions. The reservoirs can be filled by HC due to the lateralmigration of fluids from the neighbouring kitchens or from their own dominantoil-and-gas source rock strata. For the formation of oil accumulations, themost favourable are platform massifs and ancient uplifts areas.
Gadd, Peter E. (Coastal Frontiers Corporation) | Leidersdorf, Craig B. (Coastal Frontiers Corporation) | Hearon, Greg E. (Coastal Frontiers Corporation) | McDougal, William G. (Oregan State University)
Eighteen artificial (man-made) islands have been constructed in the AlaskanBeaufort Sea to support oil exploration and production. The first islands,constructed in the late 1970s, were in shallow nearshore waters where wave andice conditions are relatively benign. By the early 1980s, island constructionhad ventured to more exposed sites with water depths approaching 15 m.Innovative slope protection systems and construction methods were developed toaddress the remote Arctic locations, short construction seasons, scarce localresources, and the challenging, yet poorly defined, offshore wave and iceclimate. This paper provides an overview of the history of island developmentin the Alaskan Arctic and discusses design evolution, construction, andperformance.
Blunt, J.D. (ExxonMobil Upstream Research) | Mitchell, D.A. (ExxonMobil Upstream Research) | Matskevitch, D.G. (ExxonMobil Upstream Research) | Younan , A.H. (ExxonMobil Upstream Research) | Hamilton, J.M. (ExxonMobil Upstream Research)
The ability to keep station is recognized as a key technical demand for yearround hydrocarbon exploration, development and production operations in thehigh arctic deepwater environment. Ice management has been used as ameans to improve station keeping ability in sea ice and extend operabilitybeyond the relatively short, ice free season in the Canadian BeaufortSea. The reliability of ice management is contingent upon accurate icedrift forecasting so decisions about operation suspension in the event of apotentially unmanageable ice intrusion can be conducted in a timelymanner. This paper demonstrates tactical level sea ice drift forecastingand proposes a model for free ice drift applicable to the shoulder seasons ofthe Canadian Beaufort Sea exploration window. Model calibration isdemonstrated with real ice drift time histories and the assumptions andlimitations of the approach are discussed.
The extreme conditions and harsh environment for which FPSO's andhydrocarbon gathering facilities are being considered introduces distinctchallenges to effective and efficient project management and execution. The presentation is based on the experiences gathered during the design phasesof two contemporary harsh environment FPSO's and the associated subsea,flowline, pipeline and riser systems (Chevron Rosebank and GAZPROMShtokman). This presentation will focus on the adjustments that must beconsidered to "standard" project execution and management in order toincorporate the elemental distinctions without sacrificing efficiency, logicalsequencing, safety or project schedule. Specifically, the presentationwill focus on the following:
The paper is intended to inform the audience as to the distinctivecharacteristics of harsh environment design management contrasted with the morefamiliar benign environment design projects.
The paper will describe the existing regulatory systems for the offshore inthe Arctic. Drawing from offshore disasters and the responses thereto bythe Coastal States around the world the paper will point to the arguments forand against international regulation of Arctic offshore areas. Organizations that might create such regulation are considered such as theArctic Council, the International Maritime Organization, The InternationalRegulators Forum, the oil company operators. Current debates concerninginternational regulation such as that of the EU (October 2011) proposal tocreate EU regulations for the offshore and the opposition by the Great Britainwill be reviewed, as will be the Helix Mutual Aid solution in the Gulf ofMexico, the new Canadian filing requirements for Arctic Oil and Gas (December2012) and others.
In predicting the geotechnical constraint against pipeline movement usingfinite element methods, the treatment of the pipe/soil interface contactbehavior is of utmost importance, especially in the tangential direction. Thisstudy focuses on the interpretation of soil resistance to axial pipe movementin cohesive soil material for oblique loading, specifically the effect ofchanging the interface shear stress limit and friction coefficient. The mainfinding of the present study is that the incorporation of a shear stress limitin the definition of tangential shear behavior has a considerable effect on theaxial pipeline reaction forces. Without the shear stress limit, the maximumaxial forces due to oblique pipe movement are effectively doubled in comparisonto a limit equal to half of the undrained shear strength. A simple analyticalmethod is provided to estimate the maximum oblique axial soil resistance inundrained conditions. The effect of changing the assumed frictional behavior isalso discussed with respect to predicting the soil reaction forces acting on anice keel during an undrained gouging event in cohesive soil.
The design of offshore arctic pipelines must evaluate technical engineeringchallenges, primarily related to system demand and system capacity, and addressproject execution risk, primarily associated with pipeline trenching andlogisitics. One of the significant hazards, particularly in deeper water, isthe presence of extreme ice features; such as icebergs and multi-year pressureridges, that may gouge the seabed. A comprehensive engineering framework existsto support the analysis and design of offshore pipelines in ice gougeenvironments. However, there exists some aeas of technical uncertainty withinthe current state-of-practice that are highlighted in this paper. This studyfocuses on specific technical issues associated with the simulation of contactmechanics, definition of interface parameters, and need for physical datasetsfor the validation of advanced numerical simulation tools. Study specificconclusions and recommendations that address these technology needs to resolveuncertainty associated with the simulation of ice gouging events areprovided.