bluuebunny/crossref_metadata_2025_split huggingface dataset:
Challenges, Requirements and Advances for Distributed Fiber Optic Sensors in SURF Structures and Subsea Well Monitoring
Authors: Ravet Fabien , Rochat Etienne , Niklès Marc 
Published: November 2013

During the past 10 years, the oil and gas industry has gained confidence in the capabilities and the reliability of Fiber Optic Distributed Sensing (OFDS). Real world implementation can be found in both downstream and upstream branches. For example, at one end of the industry spectrum, service companies have started to use Distributed Temperature Sensing (DTS) for in-well temperature monitoring to optimize oil recovery processes. At the other end, pipeline operators have installed pipeline integrity monitoring systems based on Distributed Temperature and Strain sensing (DITEST) to fulfill realtime monitoring of soil stability, pipeline 3D deformation and leak detection.
The use of OFDS for offshore structure integrity monitoring such as flow lines, risers and umbilicals has been qualified and field tested already whereas other applications such as performance rating of power umbilicals and enhanced flow assurance system using OFDS are being evaluated.
Currently, the offshore full scale implementation of OFDS technologies still faces challenges of its own. In particular, sensor integration into the structure to be monitored is a minimum requirement which applies to any OFDS. If fiber optic is a common mean of data transmission, subsea conditions imply the use of specific components such as Wet Mate Connectors (WMC) and Fiber Optic Rotary Joints (FORJ). These components present large insertion and return loss characteristics for which OFDS require special attention to the OFDS system to comply with such characteristics. The effect of these components is twofold. First it impacts the sensor optical budget limiting its measurement range. Second, sensor sections remain completely blind due to the high reflection levels leaving the structure without status information over distances that can be as large as several kilometers.
The present works describes how the DITEST based on Stimulated Brillouin Scattering (SBS) can overcome the limitations imposed by both WMC and FORJ components and fully comply with SURF monitoring requirements. The ability of the DITEST is justified theoretically and demonstrated experimentally through qualification trials involving hotspot detection while WMC and FORJ are part of the sensor path. Their effects are quantified through the determination of the measurement dead zone (shorter than 4m), the temperature uncertainty and the resolution. The work also reports the subsequent installation on operational structures as these trials were successful. The DITEST has been installed to continuously monitor the temperature of a 3km long power umbilical and control the heating system of subsea rigid flowlines whose length can be as large a 45km.
Top Tensioned Riser System Design for the FHSB Dry Tree Semisubmersible Platforms
Authors: Yu Jim , Mansour Alaa M. , Yu Alan , Zuccolo Ricardo 
Published: November 2013

The dry tree production and drilling Top Tensioned Riser (TTR) systems have been extensively used with Tension Leg Platforms (TLPs) and Spar floaters in deepwater applications. However, the large heave response of the conventional Semisubmersible floaters makes this type of platforms not suitable for dry tree applications largely due to the ultra-long stroke tensioner that would be required in this case.
The Free Hanging Solid Ballast (FHSB) Semi is an innovative new semisubmersible design that is suitable for dry tree applications due to its low heave response that is comparable to that offered by Spar floaters. The new design resembles the conventional Semisubmersibles with an added free-hanging solid ballast tank placed deep below the keel of the Semisubmersible hull and connected to the hull through four groups of chains. The Solid Ballast Tank (SBT) acts as a motion damper that significantly improves the heave motion response.
In this paper, the design of the dry tree TTR system for the FHSB Semi is presented. The typical GoM’s drilling and production conditions are used in designing the TTR system including the tensioning system and the interface between the SBT and the riser keel joint. The feasibility and performance of the designed TTR system are demonstrated through static and dynamic TTR analyses.
Physics-Based Approach to Wave Statistics and Probability
Authors: Babanin Alexander V. 
Published: November 2013

Design criteria in ocean engineering, whether this is one in 50 years or one in 5000 years event, are hardly ever based on measurements, and rather on statistical distributions of relevant metocean properties. Of utmost interest is the tail of these distributions, that is rare events such as the highest waves with low probability. Engineers have long since realised that the superposition of linear waves with narrow-banded spectrum as depicted by the Rayleigh distribution underestimates the probability of extreme wave crests, and is not adequate for wave heights either, which is a critical shortcoming as far as the engineering design is concerned. Ongoing theoretical and experimental efforts have been under way for decades to address this issue.
Here, we will concentrate on short-term statistics, i.e. probability of crests/heights of individual waves. Typical approach is to treat all possible waves in the ocean or at a particular location as a single ensemble for which some comprehensive solution can be found. The oceanographic knowledge, however, now indicates that no single and united comprehensive solution is possible. Probability distributions in different physical circumstances should be different, and by combining them together the inevitable scatter is introduced. The scatter and the accuracy will not improve by increasing the bulk data quality and quantity, and it hides the actual distribution of extreme events. The groups have to be separated and their probability distributions treated individually.
The paper offers a review of physical conditions, from simple one-dimensional trains of free waves to realistic two-dimensional wind-forced wave fields, in order to understand where different probability distributions can be expected. If the wave trains/fields in the wave records are stable, distributions for the second-order waves should serve well. If modulational instability is active, rare extreme events not predicted by the second-order theory should become possible. This depends on wave steepness, bandwidth and directionality. Mean steepness also defines the wave breaking and therefore the upper limit for wave heights in this group of conditions. Under hurricane-like circumstances, the instability gives way to direct wind forcing, and yet another statistics is to be expected.
Design Advantages on Umbilical Systems Brought by a New High Performance SDSS Tube
Authors: Wagner Olivier , Durand Guy , Peultier Jérôme , Courbot Anne , Roques Jean-Philippe , Romazzotti Henri 
Published: November 2013

Subsea umbilical systems developed for deep offshore applications become more and more demanding regarding injection capacity, number of functionalities and water depth. Some applications, such as subsea boosting, subsea separation or gas lift are even more severe, leading to tube temperature, which can exceed, in some cases 70°C.
These operating conditions and requirements are significantly impacting the performance of the main umbilical. The most common solution, to avoid such issues, is to design thicker tubes to improve the strength of the umbilical cross section. The positive effect of the wall thickness increase has to be opposed to major drawbacks, such as weight increase and fatigue performance degradation generating more issues than providing solutions.
To face these challenges, Vallourec Umbilicals, with the technical support of TOTAL SA headquarter Technology Division, has developed a new manufacturing process for seam welded stainless steel tubes (SAF 2507), with higher mechanical properties and tighter wall thickness tolerances. The benefit of this innovation is to provide for a given application (i. e. pressure, water depth and temperature) thinner tubes able to meet severe operating conditions without impacting performances of the umbilical structure.
This paper, after a description of the manufacturing process and product qualification protocol (that led to a Type Approval Certificate from Bureau Veritas in October 2012), presents the technical advantages brought by seam welded solution, compared to seamless super duplex tubes.
Minimum Energy DP Heading Control: Critical Analysis and Comparison of Different Strategies
Authors: Miyazaki Michel R. , Tannuri Eduardo A. , de Oliveira Allan C. 
Published: November 2013

DP offshore operations require that the vessel reference point is controlled in relation to a fixed reference frame. In some cases, the heading is allowed to change, searching for an adequate angle in which the environmental conditions induce small loads in the hull and minimum DP power is required to keep the position. This DP mode is usually referred as “weathervane control”.
There is no exact method to determinate the minimum energy heading of a vessel in real-time with only the sensors available in a DP system. Therefore, some control strategies were developed in order to control the vessel heading, and estimate the optimal value.
This paper addresses the analysis of the final equilibrium heading of several published weathervane control strategies for two different DP vessels: a typical DP tanker and an asymmetrical DP crane-barge. A static procedure is used to calculate the final heading and the DP power and thrust demand for each controller.
Several environmental combinations of wind, current, local sea-waves and swell are considered, with a systematic variation of the intensities and the direction of the environmental agents.
For non-aligned environmental agents, differences in the final heading are verified for the zero yaw and zero sway strategies. These headings are also compared to the exact minimum power heading, obtained by an optimization procedure considering the DP thrust allocation.
Navigation in the Russian Arctic: Sea Ice Caused Difficulties and Accidents
Authors: Marchenko Nataliya 
Published: November 2013

The 5 Russian Arctic Seas have common features, but differ significantly from each other in the sea ice regime and navigation specifics. Navigation in the Arctic is a big challenge, especially during the winter season. However, it is necessary, due to limited natural resources elsewhere on Earth that may be easier for exploitation. Therefore sea ice is an important issue for future development. We foresee that the Arctic may become ice free in summer as a result of global warming and even light yachts will be able to pass through the Eastern Passage. There have been several such examples in the last years. But sea ice is an inherent feature of Arctic Seas in winter, it is permanently immanent for the Central Arctic Basin. That is why it is important to get appropriate knowledge about sea ice properties and operations in ice conditions.
Four seas, the Kara, Laptev, East Siberian, and Chukchi have been examined in the book “Russian Arctic Seas. Navigation Condition and Accidents”, Marchenko, 2012 [1]. The book is devoted to the eastern sector of the Arctic, with a description of the seas and accidents caused by heavy ice conditions. The traditional physical-geographical characteristics, information about the navigation conditions and the main sea routes and reports on accidents that occurred in the 20th century have reviewed. An additional investigation has been performed for more recent accidents and for the Barents Sea.
Considerable attention has been paid to problems associated with sea ice caused by the present development of the Arctic. Sea ice can significantly affect shipping, drilling, and the construction and operation of platforms and handling terminals.
Sea ice is present in the main part of the east Arctic Sea most of the year. The Barents Sea, which is strongly influenced and warmed by the North Atlantic Current, has a natural environment that is dramatically different from those of the other Arctic seas. The main difficulties with the Barents Sea are produced by icing and storms and in the north icebergs. The ice jet is the most dangerous phenomenon in the main straits along the Northern Sea Route and in Chukchi Seas.
The accidents in the Arctic Sea have been classified, described and connected with weather and ice conditions. Behaviour of the crew is taken into consideration. The following types of the ice-induced accidents are distinguished: forced drift, forced overwintering, shipwreck, and serious damage to the hull in which the crew, sometimes with the help of other crews, could still save the ship. The main reasons for shipwrecks and damages are hits of ice floes (often in rather calm ice conditions), ice nipping (compression) and drift.
Such investigation is important for safety in the Arctic.
Instantaneous Probability of Uncontrolled External Leakage During the Production Phase of a Subsea Well
Authors: Alves Andre L. R. , Netto Theodoro A. 
Published: November 2013

This work develops a methodology for evaluating the uncontrolled external leakage probability of a subsea well during the production phase. Based on a barrier diagram, an algorithm for possible leak paths identification is proposed, considering different operation modes: gas lift operation, free flowing or well closed at the subsea Xmas Tree.
Considering the equivalency between these paths and the minimum cut sets from a fault tree modeling, the uncontrolled external leakage probability is calculated using the upper bound approximation. The effect of common cause failures is considered for the failure mode fail-to-close-valve.
The instantaneous availability function of each component is modeled to represent the maintenance strategy applied. Non repairable, repairable and periodically tested items are used. For the latter, a nomenclature to distinguish two subtypes is introduced: the PT-R and PT-NR models, respectively Periodically Tested Repairable, and Periodically Tested Non Repairable.
Probability distributions parameters are roughly estimated in order to make a case study. The failure rate functions determined are used as input for the proposed model, regarding the following failure modes: fail-to-close, external-leakage, and internal-leakage at the closed position. The objective of this section is to adjust a Weibull distribution, eliminate the usual assumption of constant failure rate and account for eventual wear-out effects.
Finally, instantaneous probability results and sensitivity analysis are demonstrated for a base case study. Parameters like time between tests, inspections, and component reliability are varied in order to identify the impact on the uncontrolled external leakage probability. Therefore, the main objective is to propose a model that could support decision making on the well integrity management system during the production phase of a subsea well. To make this possible, reliable input data should be further considered.
Long-Range Rescue Capability for Operations in the Barents Sea
Authors: Jacobsen Sigurd R. , Gudmestad Ove T. 
Published: November 2013

The purpose of this paper is to examine the feasibility of providing long-range search and rescue for personnel in the Barents Sea. This may be due to a helicopter ditching or accident while en route to or from an offshore petroleum installation in the Barents Sea or a maritime accident. The paper will propose a combination of a SAR helicopter and multipurpose emergency response vessels. The paper will illustrate improved search and rescue capacity both for personnel involved in the petroleum industry and others i.e., fisheries, maritime transport and tourism.
The basis for this paper is petroleum exploration activity in the far North Eastern area of the Norwegian sector of the Barents Sea. The area is currently being evaluated in a process that most probably will lead to opening the area for oil and gas exploration. There is currently little or no infrastructure in the area beyond the coast. The paper considers a method to provide SAR coverage over a distance of 260 nautical miles with a minimum rescue capacity of 21 persons within two hours.
Issues related to survival in cold water, immersion survival suits and performance requirements for search and rescue resources will be considered in order to provide an optimum combination and enhanced probability of survival if an incident should occur.
Operational considerations involving departure criteria for helicopter transport should be developed in order to ensure that persons travelling on a helicopter to remote locations in the Barents Sea have a reasonable prospect of surviving a helicopter ditching and subsequently being rescued.
Multipurpose Emergency Response Vessels, ERVs, equipped with dual Fast Recovery Daughter Craft, FRDC, capable of operating in an Arctic climate deployed at the remote location and en route together with an onshore based search and rescue, SAR, helicopter may provide a rescue capacity for 21 persons within 120 minutes.
As vessels of the type proposed in this paper may be of a benefit to all stakeholders performing activities in the Barents Sea, joint venture financing by the authorities, petroleum, maritime, fishing and tourism industries could be considered.
Further Development and Benchmarking of a Novel Pipe-Soil Interaction Model for Subsea Pipeline Design
Authors: Griffiths Terry , Shen Wenwen 
Published: November 2013

For well over a decade it has been widely recognised that our existing models and tools for subsea pipeline stability design fail to account for the fact that seabed soils tend to become mobile well before the onset of pipeline instability. Despite ample evidence obtained from both laboratory and field observations that sediment mobility has a key role to play in understanding pipeline/soil interaction, no models have been presented previously which account for the tripartite interaction between the fluid and the pipe, the fluid and the soil, and the pipe and the soil.
This paper presents further development of a novel non-cohesive pipe-soil interaction algorithm which has been developed to enable modelling of pipe-soil-fluid interaction and offer a more realistic representation of the evolution of soil profiles around the pipeline compared to existing hysteresis friction spring approaches. The paper describes the methods applied to discretisation of the soil profile and interpolation between timesteps to conserve soil volume. The approach used to deform the seabed profile to account for pipe movement and predict pipeline / soil reaction forces enable the model to be benchmarked against the Verley model [12].
The model has been specifically developed to minimise computational cost compared to computationally intensive CEL continuum soil FEA approaches [6,14], but still enable the profile of the soil around the pipe to be established. This model has application to modelling of sediment transport and scour [4]. It may also offer advantages in the modelling of globally buckling pipelines where differing levels of embedment and support at buckle shoulders versus the apex of the buckle are not well handled by existing approaches. The model may also assist where existing, generally applied approaches are also not well developed to capture coupling of behaviour in axial and lateral resistances.
An Experimental Study on the Effect of Splitter Plate Angle on the VIV Behavior of Submarine Pipeline on an Erodible Bed Under Clear Water Condition
Authors: Emamgholizadeh Mohammad Javad , Mostafa Gharabaghi Ahmad Reza , Abedi Karim , Sedaaghi Mohammad Hossein 
Published: November 2013

Pipeline is an appropriate method for transmission of oil and gas from seabed hydrocarbon reservoir to the land and platform or any other place where it is needed. Free spans in the line may occur initially by an uneven seabed or be created later due to under-scouring. Vortex Induced Vibration (VIV) may occur in these free spans at high Reynolds’ numbers. Resonance can occur if the frequency of vortex shedding is close to the pipeline’s natural frequency. Otherwise, it can cause pipeline’s fatigue leading to its breakage and consequently economical and environmental losses.
In literature, different methods are presented for decreasing the scouring depth due to the vortex shedding. One of them is the application of splitter plate.
In this paper, the effect of splitter plate’s angle with horizon (α) on the vibrating behavior of pipeline with two degrees of freedom over an erodible bed is studied experimentally. The experiments were performed for reduced velocity in the range of 2.45–5.06 and gap ratio of zero. Image processing technique as a non-contact method is used for measuring the vibrations of cylinder. Experimental results indicate that the splitter plate’s angle is an important factor on the cylinder’s vibration amplitude. According to these results, for the angle in the range of 0 ≤ α ≤ 30, the vibration amplitude is decreased while its frequency is increased, but the results are vice versa for the range of 60 ≤ α ≤ 90.
Oscillation of a Net Panel With Bending Stiffness
Authors: Jensen Østen , Gansel Lars , Føre Martin , Reite Karl-Johan , Jensen Jørgen Haavind , Endresen Per Christian 
Published: November 2013

The behaviour of net panels with bending stiffness is dependent on the stiffness and potentially also the density of the material when exposed to oscillatory motions. This needs to be taken into account when net cages are product certified according to NS9415 (Standard Norge 2009). Experiments using two different net panels with bending stiffness were conducted to investigate the behaviour of nets with bending stiffness in oscillatory motion. For low oscillation frequencies the panels moved in a close to rigid body manner. When the oscillation frequencies where increased, however, there was a distinct difference between the copper and the Polyethylene Terephthalate (PET) nets, with a significant increase in the resulting oscillation amplitude for the copper net and a decrease for the PET net.
The proposed numerical model predicts this behaviour well in terms of oscillation amplitudes. It is, however, important to establish good estimates of the net panels bending stiffness in advance, particularly if product certification is the purpose of the numerical analysis.