bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrodynamic Forces on Subsea Pipelines due to Orbital Wave Effects
Authors: Karreman Annelise , Leggoe Jeremy , Griffiths Terry , King Lisa , Fogliani Nino 
Published: November 2013

Ensuring pipeline stability is a fundamental aspect of subsea pipeline design and can contribute a significant proportion of project costs in regions with large diameter trunklines, shallow water and severe geotechnical and metocean conditions [1]. Reducing the conservatism and simplifications of existing pipeline stabilisation design methods therefore offers economic benefits to hydrocarbon producers necessary to ensure the ongoing viability of projects in these regions. To realise this potential and reduce the conservatism of the existing design methods, a more accurate understanding of the hydrodynamic loads exerted by waves and currents is required.
This paper investigates one of the inherent assumptions incorporated into the existing design methods through the arrangement of previous experimental investigations to determine whether rectilinear motion provides a reasonable approximation to simulate the near seabed orbital particle paths in wind-generated waves. This assumption is based on the flattening of particle paths to ellipsoids with depth and ignores the small vertical velocity components near the seabed. Based on the hydrodynamic forces calculated numerically using a validated Computational Fluid Dynamics (CFD) model for rectilinear and orbital wave modelling it is concluded that pipeline stabilisation requirements calculated in accordance with the DNV-RP-F109 absolute lateral static stability design method and rectilinear wave motion assumption are conservative. It is also concluded that the hydrodynamic force asymmetry in favour of the reverse half wave cycle caused by the vertical velocity components in orbital wave conditions requires further consideration to determine the implication for dynamic lateral stability design methods.
Ice-Resistant Turret-Based Mobile Drilling Unit With the Wedge-Shaped Hull Approximating Ship Form (Wedge-Shaped Ship)
Authors: Blagovidov Lev B. , Kovalyov Maksym V. , Blagovidova Iryna L. , Kolchenko Leonid V. , Lenskyy Victor F. 
Published: November 2013

Nowadays, the development of Arctic oil/gas fields is still more challenging. Designing of various-type drilling unit solutions operable in rigorous ice conditions is underway to meet that challenge.
The present report includes results of the development of a promising design of an ice-resistant turret-based floating drilling unit with the hull of wedge shape similar to ice-going ship’s fore in terms of angle of bow rake, entrance angle of water line, flare of frames. This architectonic type was selected based on the survey of world experience and comparison with similar Arctic solutions.
Testing in the seaworthiness basin and ice test basin proved high seaworthiness performances of this ship. Particularly demonstrative are good controllability in ice conditions achieved by the specific hull shape and use of turret arrangement, as well as relatively lower ice loads compared with other solutions.
VIV Analysis of Deep Water Steel Catenary Riser Within Pull Tube
Authors: Qiu Lun , Lee Li 
Published: November 2013

The method of pulling a steel catenary riser (SCR) through a steel tube (termed as a pull tube) is common practice for deepwater riser tie back applications. Vortex-induced vibration (VIV) of such a system is complex. VIV analysis programs, such as Shear7 [1], are suitable only for a single, chain-like structure. The application of such a software tool in VIV design of the SCR-pull tube system requires careful consideration of a number of structural and hydrodynamic factors.
This paper presents a methodology for VIV analysis of the combined structural system of the SCR with the pull tube. Firstly, the entire SCR-pull tube system is modeled with the finite element program Flexcom [2]. The modes are then calculated for the entire structure with program Modes [3]. Afterwards, the structural nodes are rearranged for VIV analysis with Shear7. The pull tube is secured on the platform through a number of guides on the truss structure of the hull. The diameter of the pull tube is much larger than that of the SCR, and the pull tube is much stiffer in bending than the SCR is. If the entire structure is analyzed with Shear7, the mode for the pull tube (a mode involving a large motion of the pull tube section), which is very high in order, would be embedded in the analysis. It makes sense to single out the pull tube mode for study as if it is the first mode. A computer program, named as V-Span [4] for subsea span VIV analysis, is used to analyze both in-line and cross-flow VIV of the pull tube.
A numerical example is presented to demonstrate this methodology. This is a deepwater SCR, which has a diameter of 9 inches. The water depth is 6,300 ft. The pull tube is 640 feet long and 20 inch in diameter. Both the loop-eddy and background currents are analyzed. The fatigue damage resulted from both in-line and cross-flow VIV is estimated.
Validation of Solid Modeling and Analysis Techniques for Response Prediction of Deepwater Flexible Pipe
Authors: Connaire Adrian , Smyth John , Nestor Ruairi , Tanaka Rafael , Albuquerque Elson 
Published: November 2013

Accurate prediction of the load capacity of the constituent components of flexible risers and flowline structures is critical in demonstrating fitness for purpose, particularly as the envelope of application of flexible pipe is being extended to incorporate higher flow rates, greater water depths, more aggressive fluid contents and challenging installation conditions. Analytical techniques and numerical solid modelling methods have evolved significantly in recent years as a means of improving the ability to accurately predict flexible pipe load capacity.
Due to the complexity of the flexible pipe structure and the load sources and load paths to which it can be subjected, different analysis methods are required, depending on the type of response being evaluated. Specific effects can be difficult to simulate using analytical approaches and require local stress analysis using numerical techniques. This paper presents numerical approaches to two such effects, the extreme loading of tensile armour wires within a flexible pipe end fitting and the stability of tensile armour wires in axial compression.
Instrumenting Giant Piston Corers: A Decisive Step in Understanding the Coring Process and Interpreting Data
Authors: Po Stanislas , Woerther Patrice 
Published: November 2013

Giant piston corers were introduced to the marine geotechnical site investigations market towards the end of the nineties. Such corers are also used for scientific studies by research institutes as Institut Français de Recherche pour l’Exploitation de la Mer (IFREMER). Cores were observed to show distortion or mismatches between core length and the position of the sample in the soil.
The instrumentation of corer provides valuable information on the behaviour of the corer. The instrumentation also allows the correction of sample length to its true penetration.
This paper:
• Describes the instrumentation now permanently mounted on the STACOR® giant piston corer
• Presents the installation of sensors,
• Describes the data interpretation,
• Provides some recommendations for extending this monitoring to other large gravity corers.
Smoothed Particle Hydrodynamics: Benchmarking on Selected Test Cases Within the NextMuSE Initiative
Authors: le Touzé David , Barcarolo Daniel A. , Kerhuel Matthieu , Oger Guillaume , Grenier Nicolas , Quinlan Nathan , Lobovsky Libor , Basa Mihai , Leboeuf Francis , Caro Joelle , Colagrossi Andrea , Marrone Salvatore , de Leffe Matthieu , Guilcher Pierre-Michel , Marongiu Jean-Christophe 
Published: November 2013

In this paper are presented comparisons of SPH variants on academic test cases classically used to validate numerical fluid dynamics software. These comparisons are extracted from NextMuSE FP7 project activities which will be published more extensively in the near future. One of the goals of this project was to better understand the SPH method and to leave the path to its establishment within CFD methods. An important work load was thus dedicated to benchmark SPH variants on selected test cases.
A number of results and conclusions of this comparative study are presented in this paper. The studied variants are: standard weekly-compressible SPH, δ-SPH, Riemann-SPH, incompressible SPH, and FVPM. The majority of the test cases also present a reference solution, either experimental or computed using a mesh-based solver. Test cases include: wave propagation, flow past a cylinder, jet impact, floating body, bubble rise, dam break on obstacle, floating body dynamics, etc. Conclusions may help SPH practitioners to choose one variant or another and shall give detailed understanding necessary to derive further improvements of the method.
Physical Component Testing to Simulate Dynamic Marine Load Conditions
Authors: Thies Philipp R. , Johanning Lars , Gordelier Tessa , Vickers Andrew , Weller Sam 
Published: November 2013

The reliability and integrity of components used in the marine offshore environment is paramount for the safety and viability of offshore installations. The engineering challenge is to design components that are robust enough to meet reliability targets whilst lean enough to minimise cost. This is particularly the case for offshore marine renewable installations which operate in the same, possibly harsher, environment as offshore oil and gas installations, and are subjected to highly cyclic and dynamic wave, wind and operational load conditions. The cost of electricity produced has to compete with other means of electricity generation and does thus not offer the same profit margins available as oil and gas commodities. As a result, components for marine renewable installations have to meet the target reliability, without the application of costly safety factors to account for load and environmental uncertainties. Industries with similar design tasks such as the aviation or automotive industry have successfully used a service simulation test approach to develop robust yet lean designs.
This paper builds on an approach to establish and validate the reliability of floating renewable energy devices in which dedicated component testing using the purpose built Dynamic Marine Component test rig (DMaC) plays a pivotal role to assess, validate and predict the reliability of components in the marine environment. This paper presents a test rig for both static and fatigue tests of marine components such as mooring lines and mooring shackles under simulated or measured load conditions and provides two case studies from recently conducted mooring component tests. This includes an investigation into the load behaviour of synthetic mooring ropes and the ageing of mooring shackles.
U-Oscillating Water Column in Random Waves: Modelling and Performances
Authors: Malara Giovanni , Arena Felice 
Published: November 2013

This paper deals with the analytical modelling of an U-Oscillating Water Column (U-OWC). It is shown that this device can be adequately described by a nonlinear equation of motion including hydrodynamic memory effects. The excitation of the system, the added mass and the retardation function are derived by approximating the solution of a pertinent initial boundary value problem via eigen-function expansions of the (linear) velocity potential.
Next, the performance of the system is investigated in random waves by relying on Monte Carlo simulations. The excitation of the system is synthesized from a given power spectral density. Then, the nonlinear equation of motion is numerically integrated. Pertinent statistical measures are estimated for assessing the efficiency of the U-OWC in exploiting sea wave energy. In this regard, the parameters show that the device can absorb most part of the incident wave energy. Further, the device can work in safe conditions even in quite rough sea states.
Assessment of Specimen Geometry for All-Weld Metal Tensile Test in Narrow Groove Welding
Authors: Mota-Solis Noé , Ruiz Eduardo , Pelcastre Mauricio , Quintanilla Hector 
Published: November 2013

The development of adequate welding procedures for the offshore pipeline industry has required improvement of weld designs due to stringent field operations, e.g., deep and ultra-deep water application, strain-based design, weld overmatching, low temperature toughness, fatigue resistance, etc. Gas-metal arc welding (GMAW) procedures have required the optimization of the groove design, from conventional (wide opening) to narrow-groove (NG) solutions. The assessment of the weld metal tensile properties, based on international codes and specifications, is necessary to deliver full compliance and reliability of requirements for the girth weld performance. However; complexities arise in order to establish weld metal testing procedures, when narrow-groove design is used for welding a heavy-wall (HW) seamless pipe material. The latter requires the assessment of specimen geometry in HW line pipe in order to produce reliable measurements of all-weld metal tensile properties, which can be representative of the weld metal performance.
The objective of the present work is to present the assessment in the differences on specimen geometry for all-weld metal tensile test (AWMTT). The work includes the welding of a HW seamless pipe material; 273.1 mm OD × 46 mm WT, X65 steel grade using STT®+GMAW, single-torch, as welding process, with narrow J-bevel, in 2° angle opening. Experiments considered the use of an ER80S-G solid wire as filler material for behavior analysis. The assessment methodology consisted in the machining of three different specimen geometries; strip, round and cross weld specimens were prepared for tensile tests. Efforts were dedicated to extracted tensile specimens avoiding heat affected zone areas in the specimen. Assessment of obtained results is based on tensile tests as well as the analysis of stress-strain data for the yielding behavior regarding the specimen geometry.
Qualification of UOE SAWL Linepipes With Enhanced Collapse Resistance for Ultra Deepwater Applications
Authors: Arroyo Fábio , Solano Rafael F. , Mantovano Luciano , de Azevedo Fábio B. , Alves Hélio , Swanek Doug , Silva Ronaldo , Ernst Hugo 
Published: November 2013

Large diameter UOE pipes are being increasingly used for the construction of offshore pipelines. Since oil discoveries are moving towards ultra-deepwater areas, such as Pre-Salt in Brazil, collapse resistance is a key factor in the design of the pipelines.
It is known that the cold forming, and the final expansion in the UOE linepipe manufacturing process, reduces the elastic limit of the steel in subsequent compression. Due to this, the DNV collapse formula includes a fabrication factor that derates by a 15% the yield strength of UOE Pipes. However, DNV also recognizes the effect of thermal treatments and the code allows for improvement of the fabrication factor when heat treatment or external cold sizing (compression) is applied, if documented.
This paper presents the qualification of UOE pipes with enhanced collapse capacity focusing the use of a fabrication factor (αfab) equal to 1. TenarisConfab has performed a technology qualification process according to DNV-RP-A203 standard “Qualification Procedures for New Technology”. The main aspects of the qualification process are presented in this paper which included significant material and full scale testing, including combine load testing, and final analysis.
The qualification process achieved successful results and this will allow use of a fabrication factor equal to 1 directly in deepwater and ultra-deepwater offshore pipeline projects with a possible reduction in material and offshore installation costs and also potentially enhancing the feasibility of many challenging offshore projects.
Thrusters Dimensioning for Vessel’s Stationkeeping Close to Other Floating Structures: Two Case Studies
Authors: Tannuri Eduardo A. , Madureira Rafael M. L. , Igreja Haroldo 
Published: November 2013

Brazilian offshore scenario requires innovative solutions in order to increase the efficiency of operations, while still keeping the safety and the economical constraints. The global market and naval industry cannot meet the demand of the growing exploration activities, related to the recent discovery of new oil fields. Furthermore, they are located at a large distance from the shore (approximately 300km) and the environmental conditions are severe. These facts impose more logistics problems for materials and persons transportations.
The retrofitting of vessels is an alternative for increasing their operability and this option has been studied by Transpetro, subsidiary of Petrobras responsible for the Ducts, Terminals, Maritime Transport and Natural Gas segments. This paper presents two real cases of retrofitting related to the application of new technologies for positioning, including Dynamic Positioning (DP) Systems or manually operated thrusters.
In the first case, a conventional tanker will be converted to a DP2 tanker, in order to operate close to drill ships and to transfer fluids during the drilling operation. The second case is related to an offshore delivering vessel used for bunkering operation. This vessel is moored at a monobuoy, and up to 2 receiving vessels may be connected to it. An aft-azimuth thruster will be installed in the vessel, increasing its capacity to change heading in harsh environmental conditions and to keep a safe distance from the monobuoy during fast variations of environmental conditions.
Both cases require the application of a comprehensive design methodology for thruster dimensioning. The retrofitting imposes tight constraints to the layout and positioning of the thrusters. Also, the proximity to others vessels and the harsh environmental conditions in the offshore fields requires a combination of static and dynamic calculation in order to evaluate power consumption and drift motions of the vessels.
Buckling and Tensile Strain Capacity of Girth Welded 48″ X80 Pipeline
Authors: Igi Satoshi , Ohata Mitsuru , Sakimoto Takahiro , Shimamura Junji , Oi Kenji 
Published: November 2013

This paper presents the experimental and analytical results focused on the compressive and tensile strain capacity of X80 linepipe. A full-scale bending test of girth welded 48″ OD X80 linepipes was conducted to investigate the compressive strain limit regarding to the local buckling and tensile strain limit regarding to the girth weld fracture. As for the compressive buckling behavior, one large developing wrinkle and some small wrinkles on the pipe surface were captured relatively well from observation and strain distribution measurement after pipe reaches its endurable maximum bending moment. The tensile strain limit is discussed from the viewpoint of competition of two fracture phenomena: ductile crack initiation / propagation from an artificial notch at the HAZ of the girth weld, and strain concentration and necking / rupture in the base material.
The ductile crack growth behavior from the girth weld notch is simulated by FE-analysis based on the proposed damage model, and compared with the experimental results. In this report, it is also demonstrated that the simulation model can be applicable to predicting ductile crack growth behaviors from a circumferentially notched girth welded pipe with internal high pressure subjected to post-buckling loading.
Detailed Modeling of Drilling Fluid Flow in a Wellbore Annulus While Drilling
Authors: Podryabinkin Evgeny , Rudyak Valery , Gavrilov Andrey , May Roland 
Published: November 2013

To produce a well safely, the wellbore pressure during drilling must be in a range that prevents collapse yet avoids fracturing. This range is often called “the operating window”. Exceeding the limits of this range can trigger wellbore instability or initiate well control incidents. Pressure prediction requires an understanding of the hydrodynamics processes that occur in a borehole while drilling.
Describing these processes is complicated by many factors: the mud rheology is usually non-Newtonian, the flow mode can be laminar or turbulent, and the drillstring can rotate and be positioned eccentrically. Known semi-analytical approaches cannot account for the full range of fluid flows that can arise during drilling. These techniques don’t take into account all factors. Accurate numerical simulation of the flow of drilling fluids is a means to describe the fluid behavior in detail.
For numerical solutions of hydrodynamics equations a unique algorithm based on a finite-volume method and a new model of turbulence for non-Newtonian fluids was developed. The model considers string rotation and eccentricity of the drillstring. Newtonian and non-Newtonian fluids as described by the Herschel–Bulkley rheological model have been implemented. Data obtained via systematic parameter studies of the flow in a borehole are available for fast determination of parameters like pressure drop, velocity field, and stresses corresponding to any drilling condition.
Applying the new model for the annulus flow and comparing the results to the parallel plate flow approximation enabled us to quantify the error made due to the approximated solution for non-Newtonian fluid rheology.
The difference between the solutions grows as the annular gap increases. This situation is a function of the rheological parameters. Secondary flow effects can only be seen when applying the new solution method.
Avoiding Local Brittle Zones in Offshore Pipeline Girth Welds for Reeling Installation Involving Large Plastic Strain
Authors: Tronskar Jens P. , Andresen Vebjørn 
Published: November 2013

Pipelines for reeling are designed to tolerate the large plastic strain associated with the reeling installation process based on widely accepted strain based design principles for subsea pipelines as described in Det Norske Veritas (DNV) Offshore Pipeline Code OS-F101: 2012 [1].
Engineering Critical Assessment (ECA) to develop flaw acceptance criteria for automatic ultrasonic testing (AUT) for girth welds subject to large plastic strain shall according to DNV-OS-F101: 2012 [1] and DNV RP-F108 [2] be carried out in accordance with BS 7910 [3], at assessment Level 3B, with amendments and adjustments described in Appendix A of DNV-OS-F101 for strain-based loading. This is a tearing analysis using the material specific failure assessment diagram (FAD), the material stress-strain curve and the fracture resistance J-R curve (or CTOD-R curve) for the HAZ or WM. It is therefore essential that the pipeline girth welds exhibit maximum load behavior and large tearing capacity to enable development of workable and practical flaw acceptance criteria for the girth welds on the stalks.
Welds in offshore structural steels are known from the early 80s introduction of low carbon-manganese micro-alloyed steels, to occasionally exhibit low fracture toughness associated with so-called local brittle zones (LBZ) in the HAZ. Similarly, in the 90s LBZs were found in pipeline seam welds welded at high arc energies. Presence of such microstructures may have a dramatic effect on the coarse grained HAZ CTOD fracture toughness properties causing unstable fracture in the CTOD tests and CTOD values below 0.1 mm at test temperatures of 0°C and below. Recently low CTOD critical fracture toughness values due to pop-ins and unstable fracture initiation in the HAZ have been experienced for pipeline girth welds for reeling and investigation confirmed these were caused by LBZs. This paper makes a comparison with the situation experienced earlier for welds in structural steels and pipeline seam welds, to understand the factors influencing the LBZ formation, and to show how such problems can be avoided. To avoid LBZs formation in the girth welds is imperative for reeling installation, where the large plastic strain associated with reeling installation affects every girth weld.