bluuebunny/crossref_metadata_2025_split huggingface dataset:
Arctic Offshore Pipeline Design and Installation Challenges
Authors: Paulin Mike , DeGeer Duane , Cocker Joseph , Flynn Mark 
Published: September 2014

With the oil industry’s continued quest for oil and gas in frontier offshore locations, several developments have taken place in regions characterized by seasonal ice cover including the US Beaufort, North Caspian, and Sakhalin Island. In these projects, pipeline systems have been used, which are a cost-effective, safe, and reliable mode of hydrocarbon transport.
For pipeline development in Arctic, several years of data need to be collected to support the pipeline design and construction planning, and may be required by regulations. Therefore, Arctic offshore pipeline projects generally require repetitive mapping surveys and geotechnical programs to verify design loads, soil properties, and thaw settlement potential.
The major design loads that are considered for Arctic projects include ice gouging, strudel scour, upheaval buckling as well as thaw settlement. These issues can have a significant influence on the pipeline engineering considerations such as strain based design, target burial depth requirements, cost, and safety.
While important to the design of the pipeline, these issues account for just a few of the many criteria that must be considered when routing a pipeline; criteria which can be categorized as either engineering, environmental, social, administrative, or infrastructural.
The pipelines which are currently operational in the Arctic are located in shallow water depths and close to shore but were influenced by the unique Arctic environmental loading conditions. The experience from these past projects provides a significant base for the design, and operating of future offshore arctic pipelines.
Pushing the limits to developments further offshore in deeper water will require that additional consideration be given to aspects related to pipeline design, in particular with respect to burial for protection against ice gouging.
An Improved Computational Fluid Dynamics (CFD) Model for Erosion Prediction in Oil and Gas Industry Applications
Authors: Pandya Deval , Dennis Brian , Russell Ronnie 
Published: September 2014

In recent years, the study of flow-induced erosion phenomena has gained interest as erosion has a direct influence on the life, reliability and safety of equipment. Particularly significant erosion can occur inside the drilling tool components caused by the low particle loading (<10%) in the drilling fluid. Due to the difficulty and cost of conducting experiments, significant efforts have been invested in numerical predictive tools to understand and mitigate erosion within drilling tools. Computational fluid dynamics (CFD) is becoming a powerful tool to predict complex flow-erosion and a cost-effective method to re-design drilling equipment for mitigating erosion. Existing CFD-based erosion models predict erosion regions fairly accurately, but these models have poor reliability when it comes to quantitative predictions. In many cases, the error can be greater than an order of magnitude. The present study focuses on development of an improved CFD-erosion model for predicting the qualitative as well as the quantitative aspects of erosion.
A finite-volume based CFD-erosion model was developed using a commercially available CFD code. The CFD model involves fluid flow and turbulence modeling, particle tracking, and application of existing empirical erosion models. All parameters like surface velocity, particle concentration, particle volume fraction, etc., used in empirical erosion equations are obtained through CFD analysis. CFD modeling parameters like numerical schemes, turbulence models, near-wall treatments, grid strategy and discrete particle model parameters were investigated in detail to develop guidelines for erosion prediction. As part of this effort, the effect of computed results showed good qualitative and quantitative agreement for the benchmark case of flow through an elbow at different flow rates and particle sizes.
This paper proposes a new/modified erosion model. The combination of an improved CFD methodology and a new erosion model provides a novel computational approach that accurately predicts the location and magnitude of erosion. Reliable predictive methodology can help improve designs of downhole equipment to mitigate erosion risk as well as provide guidance on repair and maintenance intervals. This will eventually lead to improvement in the reliability and safety of downhole tool operation.
FHSIM — Time Domain Simulation of Marine Systems
Authors: Reite Karl-Johan , Føre Martin , Aarsæther Karl Gunnar , Jensen Jørgen , Rundtop Per , Kyllingstad Lars T. , Endresen Per Christian , Kristiansen David , Johansen Vegar , Fredheim Arne 
Published: September 2014

Numerical time domain simulations have proven applicable for analysing marine systems and operations, but available tools often target specific sub-problems or applications associated with a system or an operation. Such tools are also often limited in terms of extensions and usage. This has motivated the development of FhSim at SINTEF Fisheries and Aquaculture (SFA). FhSim is a software framework aimed at simulating especially marine systems in the time domain, using models described as ordinary differential equations (ODEs).
In this paper, we present the architecture and core functionality of the FhSim framework, including modelling, integration and 3D-visualisation. We also present a series of simulation cases which illustrate the different core properties of FhSim, including numerical simulations of aquaculture structures, model-based estimation of trawl nets and optimisation of energy systems in ships.
Logic Sequence Prevents Launching Devices Downhole Out of Sequence
Authors: de Lepeleire Ricardo , Rogozinski Nicolas , Rogers Hank , Ferrari Daniel 
Published: September 2014

Within the oil and gas industry, significant costs are often incurred by the operating company during the well-construction phase of drilling operations. Specifically, the operators cost to drill a well can cost tens or hundreds of millions of USD. One specific area where significant changes in drilling operations have occurred is in the offshore environment, specifically operations from mobile offshore drilling units (MODUs). With the ever-increasing demand for oil and gas, operators globally have increased drilling budgets in an effort to meet forecasted demand. However, the increased budgets are often eroded or offset by increasing drilling costs. Therefore, operators are continually in search of new technology, processes, or procedures to help improve drilling operations and overall operational efficiencies.
One Latin America operator identified a common operation as a possible area where operational cost could be easily reduced through the implementation of systems that allow the manipulation of valve manifolds remotely. Additionally, operating such valve manifolds remotely enhanced operational safety for personnel, which was an equally important consideration.
This paper details the evaluation of existing equipment and procedures and a process used to develop a new remote-control system using a machine logic control (MLC) that has been designed, built, tested, and deployed successfully on MODUs operating in Latin America.
Wave-in-Deck Impact Load Measurements on a Fixed Platform Deck
Authors: Scharnke Jule , Vestbøstad Tone , de Wilde Jaap , Haver Sverre 
Published: September 2014

New methods for estimation of extreme wave crest heights have resulted in an increase of the estimated 10,000 year crest height. At the Norwegian Continental Shelf this increase is typically 2 to 4 m, resulting in a crest height of 22 m to 24 m in the Central & Northern North Sea and the Haltenbanken area. As a result several fixed platforms designed prior to 2000 may experience negative air gap if being hit by the 10,000 year wave crest height. Numerical methods have been used for assessing wave-in-deck impact loads. The model tests discussed in this paper were conducted to be used as verification of the numerical codes.
For the model tests two sea states along the 10,000 year contour line were considered. Several 3-hour (full scale time) realizations were calibrated in order to capture the natural variability of the most extreme crest heights.
For wave deck impact problems, one is merely interested in the few very large wave crests out of a 3-hour simulation. A more efficient test scope would, therefore, be to generate only the largest wave groups of the realizations. For this reason the most extreme crest(s) per sea state were identified and most wave-in-deck tests were conducted by generating only the part of the time series containing the large crest(s). The wave calibration results were discussed in a previous paper, see [1].
For the wave-in-deck model tests, an existing North Sea jacket was built at scale 1:60 and instrumented in order to measure the global loads on the platform deck independently from the loads on the jacket itself. In this paper the model test setup as well as the measured wave-in-deck impact loads are discussed and compared to a simplified load prediction model. The presented results show that the simplified loading model, with wave properties based on Stokes 5th order wave theory, underestimates the measured horizontal deck loads.
On the Scalability of Model-Scale Ice Experiments
Authors: von Bock Und Polach Rudiger U. Franz , Ehlers Sören 
Published: September 2014

Ice model-scale tests are a frequently used mean to assess and predict the performance of ships and structures in ice. However, ice model-scale tests may not be treated as a black-box where any full-scale scenario can be tested and a Froude-scalable result is obtained. Prior to scaling a thorough analysis of the physical processes is required and whether they can be transferred to full-scale. Model-scale ice is an empirically developed compound-material, consisting of frozen water, voids of air and other artificial dopants. The model ice manufacturing process and dopant amounts have been adjusted to achieve Froude-scalability for the ice thickness and certain force response levels, i.e. ice resistance tests of ships breaking ice in the bending mode.
However, not much is known about the internal mechanical processes of model-scale ice and how the scaled force levels are reached. This may add uncertainty to ice model tests and their application on new fields. Recent research indicated that the internal mechanics of model-scale ice and natural sea ice are different, which is also challenging some of the existing scaling approaches.
Mechanical specimen tests in full-scale and model-scale are usually compared by stresses, i.e. relating the failure load to the cross-sectional properties. However, depending on the tests different stress combinations might lead to failure, such as different geometries and dimensions may cause qualitatively different stress distribution, which ultimately limits the comparability of the tests.
Subsequently, this paper presents a qualitative assessment on selected topics to assess the differences of model-scale ice and natural ice and the influence of the specimen geometry. Furthermore, existing scaling approaches are discussed in context with recent research findings.
How We Determine the Design Environmental Conditions and How They Impact the Structural Reliabilities?
Authors: Li Linbin , Li Ping , Liu Yuan 
Published: September 2014

This paper is based on the JIP study for the oceanographic hindcast and environmental load statistics of fixed steel structures at South China Sea under tropical cyclone conditions. It focuses on the sensitivity and comparison studies by exploring the degrees and reasons of variability that may occur in determination of design environmental conditions resulting from the selection of the design standards and approaches. The bias and efficiency in extreme values prediction are examined with respect to modeling uncertainty and statistical uncertainty. The long term distributions of maximum wave height as well as the associated wave period conditional on the design wave height are derived following the storm event based method. The approaches for combing wave, current and wind to define the design conditions and the associated biases on design load are investigated. Second order random and spreading wave theory is adopted to estimate the extreme wave crest height distributions. The extreme water level issue is addressed and recommendations are given for setting the deck elevation to achieve the explicit wave-in-deck probabilities.
The studies are carried out by applying a dataset of a grid point containing 182 typhoons spanning 40 continuous years to demonstrate the analytical procedures in an understandable fashion. The results of this paper should lead to improvements in prediction of the environmental conditions for design of new-built structures to attain their target safety levels, as well as for assessment of existing structures to demonstrate their fitness-for-purpose.
Exceptional Fatigue Performances for Umbilical’s Super Duplex Seam Welded Tube Solutions
Authors: Wagner Olivier , Thevenet Gilles , Peultier Jérôme , Roques Jean-Philippe , Romazzotti Henri 
Published: September 2014

Since the last five years, an innovative technology for umbilical’s seam welded super duplex stainless steel tubes (grade 2507, UNS S32750) has been developed in order to meet new technical challenges. An extensive program of qualification, based on 4 dimensions covering the full manufacturing range, i.e. internal diameter and wall thickness, has been set. More than 11000 test results demonstrated the efficiency and the stability of the manufacturing process. The results were also confirming the expected properties of the tubes, in term of mechanical characteristics, corrosion resistance and manufacturing tolerances. At the end of this qualification phase, a Type Approval Certificate was delivered by an independent and official certifying authority demonstrating then, the suitability of the product for offshore static applications.
The next step was to confirm the fatigue performance of the product to meet the requirements of umbilicals for dynamic applications.
This paper describes how a dedicated fatigue test protocol has been jointly defined between a Major O&G player and the tube supplier. This protocol has been built in order to test the 3 dimensions already produced during the first step of the qualification, considering tube samples with and without orbital weld. Fatigue test programs are known to be very sensitive to the test parameters, i.e. temperature, test frequency and dimensional properties of the samples. As a consequence, special attention is paid to the description of the testing methodology, the selection of the acceptance criteria and the definition of the testing parameters. Finally, the results of this program are presented and discussed in order to assess the capability of the product with respect to the defined acceptance criteria.
A New Tool for Prioritising the Risk of Failure Modes for Marine Machinery Systems
Authors: Emovon Ikuobase , Norman Rosemary A. , Murphy Alan J. 
Published: September 2014

Failure Mode Effect and Analysis (FMEA) is one of the most powerful techniques for performing risk analysis for marine machinery systems, with risk being quantified through evaluating Risk Priority Numbers (RPNs) for all failure modes of the systems. The RPN is traditionally evaluated as the product of three risk criteria; occurrence (O), severity (S) and Detection (D). FMEA has several limitations such as the challenge of aggregating experts’ risk criteria rating that may be imprecise or incomplete.
In this paper some of the limitations in the conventional FMEA technique are addressed using two approaches; AVeraging technique integrated with conventional Risk Priority Number (AVRPN) and AVeraging technique integrated with TOPSIS (AVTOPSIS). Both proposed techniques use a novel approach simple average in aggregating imprecise experts’ risk criteria ratings. A case study illustrates the suitability of both techniques for use in risk prioritisation jointly or independently as the results generated by both techniques are very similar. Furthermore, the AVRPN technique has been applied to an example from the literature and it has been demonstrated to be both computationally simple and capable of producing results which almost completely match those generated by modified Dempster-Shafer evidence theory techniques.
A Comparison Among Alternatives to Assess FPSO Roll Damping via Model Testing
Authors: de Oliveira Allan C. , Fernandes Antonio Carlos , Soares Anderson R. W. 
Published: September 2014

The prediction of the nonlinear rolling motions of a FPSO with extended bilge keels stills a challenging problem. Despite recent advantages in CFD computations, the use of model testing is considered the standard strategy for roll damping assessments. There are different ways to assess the roll damping via model testing and the three most common are the use of decay tests, tests in regular and irregular waves. The comparison among those different kinds of tests may present incoherent results, sometimes, introducing the question of which methodology is the most appropriated in those scenarios, with impact in model test specifications.
Decay tests are the easiest and the most economical way for roll assessments, but they are usually considered inaccurate compared to the other test types. Recent researches, however, have shown that a statistic approach which utilizes several decay data from the same model and loading condition improves the damping predictions. This paper provides comparisons of damping predictions from different test types based in extensive model test campaigns. It also addresses the issues and the lessons learned during the campaigns to obtain the FPSO damping database.
Nanoparticles as Fluid Loss Control Additives for Hydraulic Fracturing of Tight and Ultra-Tight Hydrocarbon-Bearing Formations
Authors: Barati Reza 
Published: September 2014

Injection of polymeric solutions, either as slick water or cross-linked fluids, in order to propagate a fracture and distribute proppants and keep the fracture open is a common practice in hydraulic fracturing of unconventional tight and ultra-tight formations. In addition to propagation of a main fracture, polymeric fluids will be invading the already existing network of micro-fractures and extending the network connected to the main fracture. Fluid loss into the matrix rock and micro-fractures is inevitable, so is the use of a comparable fluid loss additive to reduce the filtrate volume.
Different classes of nanoparticles have been used by several researchers to carry different agents including surfactants and enzymes for hydraulic fracturing purposes. Nano-sized pores and micro-sized fractures in tight and ultra-tight formations require a nano to micro-sized fluid loss additive to improve propagation of the hydraulic fractures by efficiently reducing the fluid loss.
In this study, application of silica and polyelectrolyte complex (PEC) nanoparticles as fluid loss additives for three sets of core plugs with permeability values within the 10−5 −10−4 mD, 0.01–0.1 mD and 1–40 mD range was investigated. The nano-sized material used in this study significantly reduced the fluid loss volume for the cores with permeability values below 0.1 mD when mixed only with 2% KCl or with low concentrations of guar polymer prepared in 2% KCl.
Combination of the fluid loss additive application with chemical carrying application makes these nanoparticle systems a suitable package for hydraulic fracturing of tight and ultra-tight formations.
Lifting Operations for Subsea Installations Using Small Construction Vessels and Active Heave Compensation Systems: A Simulation Approach
Authors: Halse Karl H. , Æsøy Vilmar , Ponkratov Dmitriy , Chu Yingguang , Xu Jiafeng , Pedersen Eilif 
Published: September 2014

Sub-sea installation operations require a high level of accuracy and control in order to avoid misalignment and possible collisions between modules on the sea bed. To reduce costs, smaller and lighter construction vessels are now performing these operations. The most critical parts of the operation are lift-off from the deck, passing through the splash zone, and landing sensitive equipment on the sea bed. The hazards are: high dynamic loads, resonance effects, and slack line snap. Therefore, in this study, modeling and simulation are applied to optimize design parameters and develop operational procedures for each operation to reduce risk of failure. Further, the same models can be used in operator simulator training.
Modeling and simulation of interactive multi body systems is a rather complex task, involving the vessel as a moving platform, lifting equipment such as cranes and winches, guiding devices, lifting cables and payload behavior in air, all while partly to fully submerged. It is a multi-physics problem involving hydrodynamics, mechanics, hydraulics, electronics, and control systems. This paper describes an approach to link the different models to simulate the operations including interactions between the sub-systems. The paper focuses on the modeling approach used to connect the various dynamic systems into the complete operating system. The work is in its initial phase, and some of the sub-systems models are not complete. The models are described in this paper and will be included in future work. Some initial operational examples are included, to show how the models work together.
Lateral Buckling and Walking Design of a Pipeline Subjected to a High Number of Operational Cycles on Very Uneven Seabed
Authors: Solano Rafael F. , Antunes Bruno R. , Hansen Alexandre S. , Sriskandarajah T. , Charnaux Carlos R. , Ragupathy P. , Manso Daniel 
Published: September 2014

Global buckling is a behavior observed on subsea pipelines operating under high pressure and high temperature conditions which can jeopardize its structural integrity if not properly controlled. The thermo-mechanical design of such pipelines shall be robust in order to manage some uncertainties, such as: out-of-straightness and pipe-soil interaction. Pipeline walking is another phenomenon observed in those pipelines which can lead to accumulated displacement and overstress on jumpers and spools. In addition, global buckling and pipeline walking can have strong interaction along the route of a pipeline on uneven and sloped seabed, increasing the challenges of thermo-mechanical design.
The P-55 oil export pipeline has approximately 42km length and was designed to work under severe high pressure and high temperature conditions, on a very uneven seabed, including different soil types and wall thicknesses along the length and a significant number of crossings. Additionally, the pipeline is expected to have a high amount of partial and full shutdowns during operation, resulting in an increase in design complexity. During design, many challenges arose in order to “control” the lateral buckling behavior and excessive walking displacements, and finite element analysis was used to understand and assess the pipeline behavior in detail.
This paper aims to provide an overview of the lateral buckling and walking design of the P-55 oil export pipeline and to present the solutions related to technical challenges faced during design due to high number of operational cycles. Long pipelines are usually characterized as having a low tendency to walking; however in this case, due to the seabed slope and the buckle sites interaction, a strong walking tendency has been identified. Thus, the main items of the design are discussed in this paper, as follows: lateral buckling triggering and “control” approach, walking in long pipelines and mitigate anchoring system, span correction and its impact on thermo-mechanical behavior.