Mechanical Qualification of Dynamic Deep Water Power Cable

2011 ◽  
Author(s):  
Roger Slora ◽  
Stian Karlsen ◽  
Per Arne Osborg
Keyword(s):  
Water Depth ◽  
Deep Water ◽  
Failure Modes ◽  
Electrical Power ◽  
Oil And Gas Industry ◽  
Electrical Heating ◽  
Power Cable ◽  
Water Power ◽  
System Integrity ◽  
Water Depths

There is an increasing demand for subsea electrical power transmission in the oil- and gas industry. Electrical power is mainly required for subsea pumps, compressors and for direct electrical heating of pipelines. The majority of subsea processing equipment is installed at water depths less than 1000 meters. However, projects located offshore Africa, Brazil and in the Gulf of Mexico are reported to be in water depths down to 3000 meters. Hence, Nexans initiated a development programme to qualify a dynamic deep water power cable. The qualification programme was based on DNV-RP-A203. An overall project plan, consisting of feasibility study, concept selection and pre-engineering was outlined as defined in DNV-OSS-401. An armoured three-phase power cable concept assumed suspended from a semi-submersible vessel at 3000 m water depth was selected as qualification basis. As proven cable technology was selected, the overall qualification scope is classified as class 2 according to DNV-RP-A203. Presumed high conductor stress at 3000 m water depth made basis for the identified failure modes. An optimised prototype cable, with the aim of reducing the failure mode risks, was designed based on extensive testing and analyses of various test cables. Analyses confirmed that the prototype cable will withstand the extreme loads and fatigue damage during a service life of 30 years with good margins. The system integrity, consisting of prototype cable and end terminations, was verified by means of tension tests. The electrical integrity was intact after tensioning to 2040 kN, which corresponds to 13 000 m static water depth. A full scale flex test of the prototype cable verified the extreme and fatigue analyses. Hence, the prototype cable is qualified for 3000 m water depth.

Risk Mitigation Through the Application of New Power Umbilical Technology

2012 ◽  
Author(s):  
Alan Dobson ◽  
Steven Frazer
Keyword(s):  
Aluminum Alloy ◽  
Deep Water ◽  
Risk Mitigation ◽  
Electrical Power ◽  
Structural Response ◽  
Power Cable ◽  
Enabling Technology ◽  
Effect Analysis ◽  
Design Case Study

This paper describes the substantial service life improvements that can be achieved through a new, high technology solution developed for deep water electrical power umbilical and cable applications. The new design represents an enabling technology for power cable projects in the deepest and most dynamic waters, provides a lower risk solution for risers in highly stressed conditions and can give a technically improved solution for the range of electrical power umbilical application. The significant advantages of aluminum alloy cable bundles over traditional copper cable bundles under static and dynamic loading associated with a typical deep water floating installation are presented. A design case study is used to illustrate improvements in structural response and fatigue life associated with the aluminum alloy cable cores against conventional technologies. The paper concludes with an overview of the associated risk reduction through the implementation of the aluminum alloy cables in the form of a failure mode and effect analysis.

A TLP Solution for 8000 Ft Water Depth

2010 ◽  
Author(s):  
Xiaoqiang Sean Bian ◽  
Steven J. Leverette ◽  
Oriol R. Rijken
Keyword(s):  
Motion Analysis ◽  
Water Depth ◽  
Deep Water ◽  
Upper Bound ◽  
Vibration Absorber ◽  
Design Issues ◽  
Air Spring ◽  
Coupled Motion ◽  
Integrated Platform ◽  
Water Depths

A Tension Leg Platform (TLP) solution is proposed for dry tree applications in ultra-deep water depths (∼8000 ft). Major challenges for a TLP associated with the ultra deep environment are addressed with an innovative air spring – mass vibration absorber (VAB) system introduced by SBM Atlantia. The tendon system for the TLP therefore is able to scale essentially linearly with the water depth, instead of quadratically for a conventional TLP. This paper details the integrated platform design issues, including the hull, tendon design and the coupled motion analysis approach. It also discusses the system weight and dimension scales for typical applications and the constructability in terms of their upper bound limits compared with existing platforms. A design example is presented for the offshore Brazil Santos Basin environment at 8000 ft water depth with consistent current and relatively large fatigue sea states.

Lateral Buckling of Armor Wires in Flexible Pipes: Reaching 3000m Water Depth

2011 ◽  
Author(s):  
Philippe Secher ◽  
Fabrice Bectarte ◽  
Antoine Felix-Henry
Keyword(s):  
Deep Water ◽  
Failure Modes ◽  
External Pressure ◽  
Internal Diameter ◽  
Flexible Pipe ◽  
Lateral Buckling ◽  
Flexible Pipes ◽  
Valid Solution ◽  
Sour Service ◽  
Water Depths

This paper presents the latest progress on the armor wires lateral buckling phenomena with the qualification of flexible pipes for water depths up to 3,000m. The design challenges specific to ultra deep water are governed by the effect of the external pressure: Armor wires lateral buckling is one of the failure modes that needs to be addressed when the flexible pipe is empty and subject to dynamic curvature cycling. As a first step, the lateral buckling mechanism is described and driving parameters are discussed. Then, the program objective is presented together with flexible pipe designs: - Subsea dynamic Jumpers applications; - Sweet and Sour Service; - Internal diameters up to 11″. Dedicated flexible pipe components were selected to address the severe loading conditions encountered in water depths up to 3,000m. Hydrostatic collapse resistance was addressed by a thick inner carcass layer and a PSI pressure vault. Armor wires lateral buckling was addressed by the design and industrialization of new tensile armor wires. The pipe samples were manufactured using industrial production process in the factories in France and Brazil. The available testing protocols are then presented discussing their advantages and drawbacks. For this campaign, a combination of Deep Immersion Performances (DIP) tests and tests in hyperbaric chambers was selected. The DIP test campaign was performed End 2009 beginning 2010 in the Gulf of Mexico using one of Technip Installation Vessel. These tests replicated the actual design conditions to which a flexible pipe would be subjected during installation and operation. The results clearly demonstrated the suitability of flexible pipes as a valid solution for ultra deep water applications. In addition, the DIP tests results were compared to the tests in hyperbaric chambers giving consistent results. This campaign provided design limitations of the new designs for both 9″ and 11″ internal diameter flexible pipes, in sweet and sour service in water depths up to 3,000m.

Qualification of Dynamic Deep Water Power Cable

2010 ◽  
Author(s):  
Bjorn Roger Slora ◽  
Stian Karlsen ◽  
Sjur Lund ◽  
Per-Arne Osborg ◽  
Kristian Heide
Keyword(s):  
Deep Water ◽  
Power Cable ◽  
Water Power

Long-term abrasion and corrosion damage to the Hawaii deep water power cable

2003 ◽  
Author(s):  
J. Larsen-Basse ◽  
B.E. Liebert ◽  
K.M. Htun ◽  
A. Tadjvar
Keyword(s):  
Deep Water ◽  
Corrosion Damage ◽  
Power Cable ◽  
Water Power

Gravity-Fed Riserless Coiled Tubing Operations in Ultra-Deepwater: A Milestone Achievement for Riserless Intervention and Plug and Abandonment

2021 ◽  
Author(s):  
Andrea Sbordone ◽  
Bernt Gramstad ◽  
Per Buset ◽  
Rafael Rossi ◽  
Charlie Tramier ◽  
...  
Keyword(s):  
Deep Water ◽  
Oil And Gas ◽  
Open Water ◽  
Oil And Gas Industry ◽  
Gas Industry ◽  
Norwegian Sea ◽  
Improve Efficiency ◽  
Coiled Tubing ◽  
First Time ◽  
Water Depths

Abstract In a continuous effort to reduce cost and improve efficiency, the Oil and Gas industry has been trying for the last 10 years to develop methods to perform subsea Coiled Tubing (CT) operations from a vessel and without a riser. In September 2020 a large campaign of Riserless Coiled Tubing (RLCT) coring was successfully executed in the Norwegian Sea, on the Mohns Ridge, approximately 330 nautical miles from the coast. The campaign was performed from a small Anchor Handler Tug Supply vessel, the Island Valiant. A total of 14 open water gravity-fed RLCT runs were executed in water depths between 2780 and 3085 m. The system performed extremely well and proved to be very robust, efficient and effective for these innovative operations. This was the first time that RLCT coring operations were completed without the use of a subsea injector, in the so-called gravity-fed mode, and in such ultra-deep water. This paper describes the project in detail, including the system setup used, a summary of the operations and the actual results achieved, before discussing future improvements and applications of the RLCT technology.

Flexible Riser Resistance Against Combined Axial Compression, Bending, and Torsion in Ultra-Deep Water Depths

2005 ◽  
Author(s):  
Marcelo Brack ◽  
Le´a M. B. Troina ◽  
Jose´ Renato M. de Sousa
Keyword(s):  
Axial Compression ◽  
Deep Water ◽  
Failure Modes ◽  
External Pressure ◽  
Combined Loading ◽  
Test Procedures ◽  
Pipe Length ◽  
Potential Failure ◽  
Technical Specifications ◽  
Water Depths

The experience in the Brazilian offshore production systems is to adopt the traditional riser solution composed of unbonded flexible pipes at a free-hanging catenary configuration. In deep waters, the tendency has been to use different pipe length sections (normally two), each of them designed to resist typical loadings. At the bottom, pipe structure is dimensioned against external pressure, axial compression, bending and torsion, for example. The theoretical prediction of riser responses under the crescent combined loading conditions is a key issue at the TDP region. The potential failure modes are buckling of the armour tendons and also rupture of the high resistance tapes. Much effort has been done in order to have available, from the market, larger envelopes of certified methodologies and qualified products, applicable to the Brazilian ultra-deep scenarios. Since 2002, an extensive R&D Program has been conducted (i) to improve current design evaluation tools & criteria and (ii) to establish representative test procedures and scope, for prototype qualification against the potential failure modes associated with combined axial compression, bending and torsion, at the TDP regions of bottom riser sections in ultra-deep water depths. This paper describes the main steps of the R&D Program, as below: I. Improvement of computational tools to better represent the behavior of the tendons, II. Consolidation of a new strategy for structural analysis, under more realistic conditions, III. Issue of a more adequate set of pipe technical specifications, and IV. Review of both theoretical and experimental results obtained from Feasibility Technical Studies and offshore field tests, respectively. Some examples and results are showed to illustrate, step by step, the whole process covered by the cited Program. Finally, the authors document their main conclusions for further discussion.

Comparative Study of Spar-Type Wind Turbines in Deep and Moderate Water Depths

2012 ◽  
Author(s):  
Madjid Karimirad ◽  
Torgeir Moan
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Water Depth ◽  
Deep Water ◽  
Offshore Wind ◽  
Hydrodynamic Performance ◽  
Offshore Wind Turbine ◽  
Spar Platforms ◽  
Water Depths ◽  
Coupled Wave

This paper compares the dynamic responses and performance of two spar-type wind turbines, DeepSpar and ShortSpar, in deep and intermediate water depths, respectively. The oil and gas industry has implemented spar platforms in deep water areas. Spar platforms show good hydrodynamic performance due to their deep draft. The same idea is applied to offshore wind turbines to present a reliable concept. Hywind is an example of a successful offshore wind turbine based on the spar concept in deep water. The good performance of spar-type wind turbines motivates us to study the feasibility of using these turbines in moderate water depth. Spar-type 5-MW wind turbines in deep and moderate water depths are compared. The power performance, dynamic motions, tension responses, accelerations, structural shear forces and bending moments are studied. Simo/Riflex/TDHMILL3D is used to perform the coupled wave- and wind-induced analyses. Simo/Riflex, developed by MARINTEK, is a commercial tool for analyzing the coupled wave-induced responses of moored offshore structures. TDHMILL3D, is an external DLL that accounts for spar motions while calculating the aerodynamic thrust at each time step using the turbine characteristics and relative velocities. Different environmental conditions are used to compare the responses. The results show that spar-type wind turbine in the moderate water depth exhibits good performance and that its responses are reasonable compared to those of spar-type wind turbine in deep water. This finding indicates the feasibility of implementing the same rotor-nacelle assembly for both concepts. The total mass (the structural mass plus the ballast) of the ShortSpar is 35% less than that of the DeepSpar, while the statistical characteristics of the power generated are almost the same. The reduced mass of the ShortSpar helps to achieve a more cost-effective solution for floating wind turbines in moderate water depth.

Informing Components Development Innovations for Floating Offshore Wind Through Applied FMEA Framework

2020 ◽  
Author(s):  
Giovanni Rinaldi ◽  
Philipp Thies ◽  
Lars Johanning ◽  
Paul McEvoy ◽  
Georgios Georgallis ◽  
...  
Keyword(s):  
Deep Water ◽  
Failure Modes ◽  
Low Cost ◽  
Cost Savings ◽  
Offshore Wind ◽  
Mitigation Measures ◽  
Power Cable ◽  
Floating Platform ◽  
Potential Cost ◽  
Mooring Lines

Abstract Future offshore wind technology solutions will be floating to facilitate deep water locations. The EUH2020 funded project FLOTANT (Innovative, low cost, low weight and safe floating wind technology optimized for deep water wind sites) aims to address the arising technical and economic challenges linked to this progress. In particular, innovative solutions in terms of mooring lines, power cable and floating platform, specifically designed for floating offshore wind devices, will be developed and tested, and the benefits provided by these components assessed. In this paper a purpose-built Failure Modes and Effect Analysis (FMEA) technique is presented, and applied to the novel floating offshore wind components. The aim is to determine the technology qualification, identify the key failure modes and assess the criticality of these components and their relative contributions to the reliability, availability and maintainability of the device. This will allow for the identification of suitable mitigation measures in the development lifecycle, as well as an assessment of potential cost savings and impacts of the specific innovations. The methodology takes into account inputs from the components developers and other project partners, as well as information extracted from existing literature and databases. Findings in terms of components innovations, their main criticalities and related mitigation measures, and impacts on preventive and corrective maintenance, will be presented in order to inform current and future developments for floating offshore wind devices.

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