Application of Composite Materials in Deep Water Offshore Platforms

Truncated vertical circular cylinders are used to make deep water floating offshore platforms like Truss Spars. When the draft of the cylindrical hull is not deep enough, prediction of the surge and pitch diffraction loads by integration of McCamy and Fuchs expression of the force per unit length over the cylinder draft causes an error which is not negligible. Using hydrodynamic arguments the approximated surge and pitch loads by McCamy and Fuchs diffraction theory are modified. The modified results are compared with the results of a parametric study using the computer program WaMIT 4.01 based on the linear diffraction theory, reported by Weggel [1].

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Anchor Deployment Planning Using Simulated Annealing

21st International Conference on Offshore Mechanics and Arctic Engineering, Volume 4 ◽

10.1115/omae2002-28067 ◽

2002 ◽

Author(s):

Oscar Brito Augusto

Keyword(s):

Simulated Annealing ◽

Objective Function ◽

Deep Water ◽

Simulated Annealing Algorithm ◽

Production Systems ◽

Offshore Platforms ◽

Additional Advantage ◽

Floating System ◽

Deployment Planning ◽

Planning Methodology

In this work a planning methodology for deep-water anchor deployment of anchor lines for offshore platforms and floating production systems aiming at operational resources optimization is explored, by minimizing a multi criteria objective function. A Simulated Annealing Algorithm was used to optimize the objective function. As an additional advantage, inherited from the proposed methodology, the planning automation is achieved. Planning automation overcomes the traditional way based on trial error exercise, where an engineer using an anchoring application, decides how much of work wire and anchoring line must be paid out from both the floating system and the supply boat and additionally which horizontal force must be applied to the line trying settle the anchor on a previously defined target in the ocean floor. Some cases, from anchor deployment of some MODUs operating in deep-water oil fields in Brazil, are shown demonstrating some potentialities of the proposed model.

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Technology of steel jackets load-out in deep-water offshore platforms from the barge

Azerbaijan Oil Industry ◽

10.37474/0365-8554/2020-2-25-29 ◽

2020 ◽

pp. 25-29

Author(s):

F.G. Hasanov ◽

Keyword(s):

Deep Water ◽

Great Majority ◽

Problem Solution ◽

Offshore Platforms ◽

The Caspian Sea ◽

Gas Field ◽

Steel Jacket ◽

Gravity Centre ◽

Scientific Technical ◽

Oil Gas

Currently, great attention is paid to the development issue of the shelf’s fuel and energy resources foremost in the oil-gas fields of the Caspian Sea. The problem solution requires the studying of great majority of scientific-technical issues. One of the significant problems is the lead-out of steel jacket from the offshore platform as a major element of oil-gas field hydro-technical facilities meant for the operation in the deep water. The calculations for the execution of operations with steel jacket of deep stationary platform from the block with the detailed chara- cteristics by the mass and gravity center coordinates alongside line data have been carried out with “SACS” and “STAAD.PRO” software programs. The steel jacket is pushed astern with the push-pull equipment on the barge. Due to the shift of gravity centre the jacket changes the trim in the stern. Through the elevation of trim angle brought in alignment with the friction ration between the jacket and barge, the jacket slides further itself. Herewith, the trim increases until the gravity centre of steel jacket on the barge is not in alignment with rotation centre of the large rocker arms. The studies helped to fix the position of the jacket’s gravity centre from the aft perpendicular, the trim moment, the trim of the barge, the draft with the bow and stern and the trim angle as well.

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Economical Proposal for an Offshore Logistic Hub

Volume 1: Offshore Technology ◽

10.1115/omae2017-61019 ◽

2017 ◽

Author(s):

Peyman Asgari ◽

Antonio Carlos Fernandes

Keyword(s):

Rigid Body ◽

Frequency Domain ◽

Deep Water ◽

Vertical Motion ◽

Panel Method ◽

Offshore Platforms ◽

Oil Exploration ◽

Remote Terminal ◽

Floating Breakwater ◽

Two Bodies

Oil exploration in the pre-salt, mainly in the SANTOS BASIN, has increased significantly and as results increasing the number of thousands of people commute to offshore platforms in Brazil is inevitable. The presence of a remote terminal, the so-called HUB, adjacent to the platforms, not only reduces the shipment costs, but also increases the speed of commuting. The present work addresses the feasibility of utilizing a ship shape hull as an alternative logistic HUB. The present work analyzes the hull as a rigid body receiving mostly transversal waves and operating as a floating breakwater in deep water with a central turret. The crew boat is a HSV, which will also be included in the investigation. As a continuation of the previous study of the author in 2015, the relative vertical motion between two bodies is analyzed in (four) different configurations and angles of incoming waves by the panel method code in frequency domain. Finally, having in mind operation limits and criterion, operation probabilities are evaluated. Four configurations are considered to be analyzed numerically on the relative vertical motion between two bodies in different Configurations and different angles of incoming waves by a panel method code for frequency domain. Finally, operation probabilities are studied according to the operation limits and criterion.

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Optimal Design Methodology for Multi-Component Mooring Systems in Deep Water

29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 4 ◽

10.1115/omae2010-20190 ◽

2010 ◽

Author(s):

Long Yu ◽

Jiahua Tan

Keyword(s):

Optimal Design ◽

Deep Water ◽

Design Methodology ◽

Element Model ◽

Gas Production ◽

Mooring Line ◽

Mooring System ◽

Offshore Platforms ◽

Mooring Lines ◽

Restoring Force

Multi-component mooring systems, one of the crucial equipments of offshore platforms, play an important role in deep water oil&gas production because of relative low cost and light weight. A single mooring line can be constructed by combination of wire ropes, chains, fiber ropes, buoys and connectors etc. and provide adequate restoring force at fairlead point of platforms. Although the static and dynamic analyzing approaches for a determined multi-component system have been studied already, it is still hard to design and predetermine an appropriate mooring system that can satisfy the codes with multi-component lines. Referred to the conventional mooring system design method, this paper brings out an optimal design methodology for multi-component mooring systems. According to quasi-static method, at extreme offset position of the platform, an optimization model for designing the multi-component mooring line with biggest tension in deep water has been provided. Then, with the aid of design wave method and morison equation, a finite element model has been used to calculate mooring line dynamics at each fairlead point in time domain. The nonlinear interaction of mooring lines and seabed has also been investigated. Heave and surge of the platform have also been considered. Both 2D and 3D mooring system models have been built to search the interference of the lines and directional influence of environment loads like current and wave. The paper applied this set of analyzing methods and processes into a deep water semisubmersible serving at South China Sea. Compared with the results calculated by other software, the methodology mentioned in the paper got similar result with less weight and bigger restoring force.

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Research Improving the Safety of Offshore Helicopter Operations

Marine Technology and SNAME News ◽

10.5957/mt1.2005.42.1.34 ◽

2005 ◽

Vol 42 (01) ◽

pp. 34-42

Author(s):

Stephen J. Rowe ◽

David Howson ◽

Paul Sparkes

Keyword(s):

Continental Shelf ◽

North Sea ◽

Deep Water ◽

Weather Conditions ◽

Offshore Platforms ◽

Research Themes ◽

The Uk ◽

Helicopter Transportation

With the development of the Gulf of Mexico's deep-water fields, helicopter transportation is being required to serve larger offshore platforms located at greater distances from the shore. Although the weather climate is relatively benign, the helicopter operations to these new platforms are becoming more akin to North Sea operations. In particular, the requirement to evacuate large and distant platforms in advance of a hurricane may put a particular premium on demonstrating the safety of such operations in worsening weather conditions. The paper outlines progress and gives example results from a number of research themes aimed at improving the safety of helicopter operations on the UK continental shelf. The themes include ways of minimizing the risk posed by the aerodynamic hazards in the vicinity of helidecks on large offshore platforms, improving the emergency flotation systems for helicopters forced to ditch in the sea, and improving the crashworthiness of such systems so that helicopters that crash into the sea are more likely to float following impact. New motion criteria being developed for operations to helidecks on floating vessels and improvements to helideck lighting schemes are also described.

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Multiscale Analysis of Multilayer Composite Pipes

10.31219/osf.io/nse82 ◽

2018 ◽

Author(s):

DC Pham

Keyword(s):

Composite Materials ◽

Composite Structures ◽

Offshore Platforms ◽

Fiber Reinforced ◽

Stick Slip ◽

Flexible Fiber ◽

Non Linear ◽

Bonded Composite ◽

Laminate Cylinder ◽

Composite Pipes

The use of composite materials in offshore applications has constantly increased towards the development of deepwater technology and ultra-deepwater feasibility. Cylindrical composite pipes are the most principal components in floating and offshore platforms. Composite pipes could be grouped into bonded and unbonded structures. Typical bonded composite structures comprise a core angle ply laminate cylinder sandwiched between an inner liner and an outer liner made of elastomer or metal alloys. On the other hand, unbonded composite pipes such as flexible pipes in floating platforms consist of multiple metallic and polymeric layers, among which tensile wires play essential roles in providing axial and bending stiffnesses. The flexibility in motion of each layers of the unbonded composite pipe and the complexity in their geometries and materials make the analysis of unbonded composite structures very challenging. In this work, multiscale non-linear analyses of unbonded flexible risers are carried out and the non-linear behaviors of individual riser layers as well as stick-slip mechanisms between them are studied. In addition, the work also discusses the potential of flexible fiber-reinforced pipe where metal amour strips may be replaced by fiber-reinforced composite materials to significantly enhance the structural performance of conventional pipe.

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Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

Journal of Paleontology ◽

10.1017/s0022336000058819 ◽

1988 ◽

Vol 62 (01) ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Ronald E. Martin

Keyword(s):

Deep Water ◽

Benthic Foraminifera ◽

Carbonate Platform ◽

Sedimentary Facies ◽

Depositional Environments ◽

Near Surface ◽

Sediment Gravity Flows ◽

Gravity Flows ◽

Platform Margin ◽

Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

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Comparative Microstructures of Ion Milled and Electrochemically Thinned Composite Materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052742 ◽

1974 ◽

Vol 32 ◽

pp. 546-547

Author(s):

R.R. Russell

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Composite Materials ◽

Great Difficulty ◽

Ion Milling ◽

Transmission Electron ◽

Ion Damage ◽

Intermetallic Composite

Transmission electron microscopy of metallic/intermetallic composite materials is most challenging since the microscopist typically has great difficulty preparing specimens with uniform electron thin areas in adjacent phases. The application of ion milling for thinning foils from such materials has been quite effective. Although composite specimens prepared by ion milling have yielded much microstructural information, this technique has some inherent drawbacks such as the possible generation of ion damage near sample surfaces.

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