bluuebunny/crossref_metadata_2025_split huggingface dataset:
Guest Molecule Exchange Kinetics for the 2012 Ignik Sikumi Gas Hydrate Field Trial
Authors: White Mark , Suk Lee Won 
Published: June 2014

Abstract
A commercially viable technology for producing methane from natural gas hydrate reservoirs remains elusive. Short-term depressurization field tests have demonstrated the potential for producing natural gas via dissociation of the clathrate structure, but the long-term performance of the depressurization technology ultimately requires a heat source to sustain the dissociation. A decade of laboratory experiments and theoretical studies have demonstrated the exchange of pure CO2 and N2-CO2 mixtures with CH4 in sI gas hydrates, yielding critical information about molecular mechanisms, recoveries, and exchange kinetics. Findings indicated the potential for producing natural gas with little to no production of water and rapid exchange kinetics, generating sufficient interest in the guest-molecule exchange technology for a field test. In 2012 the U.S. DOE/NETL, ConocoPhillips Company, and Japan Oil, Gas and Metals National Corporation jointly sponsored the first field trial of injecting a mixture of N2-CO2 into a CH4-hydrate bearing formation beneath the permafrost on the Alaska North Slope. Known as the Ignik Sikumi #1 Gas Hydrate Field Trial, this experiment involved three stages:the injection of a N2-CO2 mixture into a targeted hydrate-bearing layer,a 4-day pressurized soaking period, anda sustained depressurization and fluid production period. Data collected during the three stages of the field trial were made available after an extensive quality check. These data included continuous temperature and pressure logs, injected and recovered fluid compositions and volumes. The Ignik Sikumi #1 data set is extensive, but contains no direct evidence of the guest-molecule exchange process. This investigation is directed at using numerical simulation to provide an interpretation of the collected data. A numerical simulator, STOMP-HYDT-KE, was recently completed that solves conservation equations for energy, water, mobile fluid guest molecules, and hydrate guest molecules, for up to three gas hydrate guest molecules: CH4, CO2, and N2. The independent tracking of mobile fluid and hydrate guest molecules allows for the kinetic exchange of guest molecules between the mobile fluids and hydrate. The particular interest of this numerical investigation is to determine whether kinetic exchange parameters, determined from laboratory-scale experiments, are directly applicable to interpreting the Ignik Sikumi #1 data.
Case Study of Geotechnical Site Investigation using a Seafloor Drilling Unit, Large-diameter Cores, and Coring-vessel-deployed Cone Penetration Tests in the Gulf of Mexico
Authors: Caruthers C. , Hartsfield R. , Young A.G. , Spikula D. , Dobias J. , Fitzpatrick M. , Remmes B. 
Published: June 2014

Abstract
This paper compares results of a deepwater geotechnical investigation using a seafloor drilling system, large-diameter core samples, and cone penetration tests performed from a coring vessel with results of a geotechnical investigation performed from a conventional drillship. The paper reports the first use of a seafloor drilling unit in the Gulf of Mexico to conduct a geotechnical site investigation for the mooring design of a floating platform.
Common practice in the Gulf of Mexico for geotechnical investigations of anchor spreads for moored production facilities has been to perform seafloor cone penetration tests and to drill and sample one or more soil borings. "Soil borings" are prescribed but not defined by 30 CFR 250.19 API RP 2SK1 recognizes currently available site investigation tools, such as large-diameter core samples, that could be used in lieu of rotary soil borings; however, some certified verification authorities/agents (CVAs) have been reluctant to accept the use of API-accepted methods of site investigations in the Gulf of Mexico. Seafloor drilling units have been used successfully in various parts of the world, and cone penetration tests from a coring vessel have been performed and studied at numerous sites, both in the Gulf of Mexico and worldwide. This paper demonstrates that a seafloor drilling unit, large-diameter cores, and coring-vessel-deployed cone penetration tests integrated with AUV subbottom profile data can be used in the Gulf of Mexico without reliance on samples obtained from a drillship.
Cone penetration resistance is compared using different cone systems and deployment methods at nearby locations. Results are essentially identical. Representative soil sample data are compared, and geotechnical laboratory test results are very similar. The paper confirms that when ASTM standards for cone testing and thin-walled-tube sampling are used, consistent results can be obtained from site investigations performed from seafloor drilling units and coring vessels or purpose-built geotechnical drillships. Integrated site investigation programs using technologies such as seafloor drilling units, large diameter coring, and cone penetration testing from a coring vessel should be acceptable for site investigations without special regulatory approvals beyond those that would apply to a site investigation program performed from a purpose-built geotechnical drillship.
AUV-Based 3D Laser Inspection for Structural Integrity Management in Deepwater Fields
Authors: Reeves T. , McLeod D. , Embry C. , Nickerson B. 
Published: June 2014

Abstract
Lockheed Martin has developed the capability to conduct AUV-based structural survey and post-hurricane platform inspection using 3D mapping and change detection with a 3D sonar. Successful validation trials for this technology were conducted with the Marlin® AUV during the summer of 2011 and the first commercial operations were conducted in the summer of 2012.
Lockheed Martin Corporation, in partnership with underwater laser developer 3D at Depth LLC, and supported by funding from the Research Partnership to Secure Energy for America (RPSEA), is now extending its revolutionary 3D modeling and change detection to employ a 3D laser sensor, thereby improving model resolution and accuracy by an order of magnitude, from centimeter scale to millimeter scale. AUVs outfitted with 3D Laser imaging systems will provide new, high accuracy tools for subsea integrity management that are currently used extensively in terrestrial applications, including High Definition Scanning (HDS) for close-in inspection of problem areas, and underwater LIDAR (LIght Detection And Ranging) for 3D mapping and inspection of flowlines, risers, and other subsea infrastructure.
The scope of this project is to develop and demonstrate the technology required to conduct AUV-based 3D-laser imaging utilizing 3D mapping and change detection. Objectives include demonstration of close-in, high resolution underwater structural inspection, generation of high resolution 3D models of subsea structures, and performance of change detection of flaws or damage against a priori structural models.
This paper will detail the results achieved to-date and will highlight the 3D Laser performance improvements over current platform inspection methods, including significant improvements in operating efficiencies and the development of accurate 3D models for use in structural integrity management.
Integrating hydrodynamic and nautical studies for offshore LNG operations
Authors: Voogt Arjan , Wilde Jaap de , Dekker Johan 
Published: June 2014

For offshore LNG production, the ability to safely offload LNG to shuttle carriers is an important driver in the design. Hydrodynamic studies and nautical studies can be used to select an offloading concept, optimize the operational procedure and evaluate the terminal availability. These studies involve mariners and mathematics. Full mission bridge simulators are traditionally used to train for the operation and to evaluate its feasibility. By incorporating state-of-the-art hydrodynamic models, the full mission bridge simulator can also be used for concept engineering. This allows a bridge between design and operation. It provides feedback from the operation into the design and improves operational guidance. This paper shows examples of this approach, while evaluating both tandem and side-by-side offloading.
With hydrodynamic studies the relative motions and mooring loads between the permanently moored vessel and the transport vessel are estimated. This paper concludes that 97% weather uptime can be achieved in waves with up to 3 meters significant height for side-by-side while the same uptime can be achieved in waves up to 5 meters for dynamic positioned tandem offloading. Tandem offloading is often perceived as a safer option than side-by-side offloading, due to the larger distance between the vessels. Although the tandem configuration seems more promising for offshore offloading, it requires new technology for LNG transfer, which is why it has not yet been applied. Integrating hydrodynamic and nautical studies can help to evaluate cryogenic hose handling and tug operations during the final phase of the approach and departure of the LNG carrier.
BP Angola PSVM Project: Production Flowline Lateral Buckling Design
Authors: Cooper P.A. , Crawford M.J. , Bell M. 
Published: June 2014

Abstract
The BP Angola Programme focuses on the development of a number of deepwater oil production projects within the Angolan Offshore Block 31 and 18. PSVM is the first field under development within Angola Offshore Block 31 and uses a centrally located FPSO with subsea ‘offline’ manifolds and clustered wells located in water depths up to a maximum design of 2100m. The extensive production flowline system features three "hybrid loops", compromised of highly insulated pipe-in-pipe production flowlines, with the remote end linked to the host FPSO by a single wall service flowline for dead oil displacement and inspection pigging.
During the design, a number of technical challenges were identified, requiring collaborative approaches and complex numerical analysis to develop a robust final solution. These challenges included balancing the effects of sour produced fluids and slug flow on fatigue strength, with the thermo-mechanical design including buckling and walking mitigation. The combination of a heavy pipe-in-pipe cross section and very soft seabed soils further complicated the design. The buckling design solutions developed were compatible with installation in 2km water depth, used proven and qualified methods and materials and ensured integrity for the 25 year design life.
This paper outlines the approach to thermal expansion management through engineered lateral buckles. The selection of buoyancy sections in preference to sleeper arrangements, which have been popular in the past, are explained.
The main features of the final design are described, including procurement, construction and installation considerations. Observed buckling response from commissioning and early production is compared with design predictions, and key lessons learnt are shared.
The paper seeks to demonstrate the merits of buoyancy modules in preference to sleepers as buckle mitigation devices for deepwater flowlines. Key design considerations are identified, and a rational design process consistent with SAFEBUCK and DNV guidance is outlined.
Numerical Simulation of Floating Offshore Wind Turbines Including Aero-Elasticity and Active Blade Pitch Control
Authors: Sweetman Bert , Wilder Blake 
Published: June 2014

Abstract
A new numerical methodology is presented for simulation of dynamic behavior of floating offshore wind turbines. Wind forces are computed in the time domain through application of blade element momentum theory using the instantaneous wind velocities, blade pitch angles, and resulting rotor speed. Equations of motion are developed and solved in Euler-space, such that no small-angle assumptions are required in the solution; vessel motions are included in wind and wave force calculations. Aero-elastic effects are quantified using the industry-standard subroutine AeroDyn, with blade pitch-angles computed by the "DISCON" subroutine, both open-source and publicly available from the National Renewable Energy Lab (NREL). Effectiveness is demonstrated through a series of examples, first a case for small-angle motion is compared with results from an industry standard simulation tool for the spar-based NREL OC3-Hywind with constant wind speed and no waves; next, the same environmental conditions are applied to a smaller spar-based floater for which standard simulation tools would not be applicable. Finally, a case is presented including irregular winds and waves.
Canada's Cabled Ocean Observatories
Authors: Moran Kate , Pirenne Benoit , McLean Scott , Round Adrian , Juniper Kim , Macdonald Nikki , Madden Peter 
Published: June 2014

Abstract
Ocean Networks Canada (ONC) is the not-for-profit agency responsible for the management of VENUS, the coastal observatory, and NEPTUNE, the regional observatory, on behalf of the University of Victoria, lead institution for a pan-Canadian consortium of universities, industries and government agencies. ONC's vision is to be a world leading organization supporting ocean discovery and technological innovation.
ONC's mission is to enable transformative ocean research and technology development through an innovative cabled infrastructure that supplies continuous power and Internet connectivity to a broad suite of novel subsea instrumentation in coastal and deep-ocean environments.
Operating Performance Forecasting and Evaluation of an FPSO with Degrading Mooring System Components
Authors: Carra C. , Wales S. , Gumley J. , Jobson B. , McDonnell S. , Mir U. 
Published: June 2014

Abstract
Integrity management of mooring systems on floating structures has been gaining interest over the last few years, as a result of increasing interest in life extension of existing assets and the reported increase in the number of mooring system failures. During the second half of 2012, OMV New Zealand Ltd commenced planning for a detailed inspection program of all underwater assets in the Maari Field, including the mooring system for the FPSO Raroa. When conducting the campaign in early 2013, a series of anomalies were found, including birdcages in wire sections of adjacent mooring legs. Through a regime of coordinated metocean forecasting, metocean monitoring, FPSO position monitoring, numerical modelling and ongoing inspection, OMV New Zealand was able to effectively manage an FPSO found to have multiple adjacent degraded mooring lines through a winter season until repairs could be completed. The development of a concurrent numerical model of the actual mooring system proved to be indispensable in achieving this objective and in facilitating the day-to-day operation of the facility over this period. Being able to verify numerical predictions against actual vessel motion response data in combination with detailed site metocean data significantly enhanced the value of the numerical model. The numerical model was employed across a wide range of activities from forecasting performance, evaluation of hypothetical multi line failure scenarios, interpretation of measured performance, determination of sea state limits and inspection triggers, through to the remediation engineering of the system. Of particular importance for the Maari situation was the early detection of potential line failure on the degraded leeward mooring legs, which was heavily reliant on comparisons of numerical predictions against observed system behavior.
Signatures of Mid-Water Jets in the Gulf of Mexico BOEM NTL Dataset
Authors: Magnell Bruce A. , Ivanov Leonid I. 
Published: June 2014

Abstract
We discuss the results of a process-oriented analysis of current profile measurements collected from 2005 through 2010 in the Gulf of Mexico by oil industry operators, who are required to measure ocean current profiles and transmit these data in near-real-time. The individual data ensembles are sent to NDBC where they are processed, quality checked, archived and made available to the public through the NDBC website. WHG performed a thorough inspection of the data, including a review of the temporal and spatial continuity of the data, cross-check between neighboring stations and between current data and satellite altimetry charts, and verification of the metadata using independent sources of [1].
The cleaned and quality-controlled data were analyzed to identify and classify the observed cases of stronger currents. The analysis identified 140 cases of current events characterized by a subsurface ‘jet’ peaking at 30–50 cm/s that does not have a surface expression.. In most of the mid-water current events identified in the 2005–2010 NTL data, the current speed peak is located somewhere between 300m and 800m, most frequently around 500m, much deeper than similar patterns identified in earlier studies. Some of the events identified in our study lasted for less than one day, but many events were of a much longer duration. Most of these events were observed southeast of the Mississippi delta and had horizontal scales over 15 miles and lingered in the area for an extended period of time. Some of the identified events were caused by strong inertial oscillations with multiple speed peaks confined to a relatively narrow layer centered around 500m. Mid-water jets have been identified in previous work [2] but this new analysis provides far more cases and suggests that the jets have an upper limit of about 50 cm/s. Such magnitudes are unlikely to govern extreme loads on offshore risers or tendons but they could be a factor in fatigue.
Qualification of UOE Linepipes with Enhanced Collapse Resistance
Authors: Arroyo Moreira F. , Silva R.C. , Mantovano L.O. , Solano R.F. , Azevedo F.B. , Alves H. 
Published: June 2014

Abstract
Large diameter UOE pipes are being increasingly used for the construction of offshore pipelines and in the last few year, 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 the demand for pipes with high thickness near the limits for fabrication and installation capacity. It is known that the cold forming, and the final expansion in the UOE line pipe manufacturing process, reduces the elastic limit of the steel in subsequent compression. Due to this, the DNV collapse formula includes a fabrication factor that de-rates 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. In previous work [1] it was presented the qualification of UOE pipes with enhanced collapse capacity focusing the use of a fabrication factor (alpha-fab) equal to 1. A technology qualification process according to international standard has been performed. The main aspects of the qualification process were presented and included significant material, full scale testing and final analysis. In this paper, we compare those results with the ones of the new qualification tests analyzing the more important variables affecting the collapse resistance such as ovality, compressive material strength, thermal treatment control, etc. This new qualification obtained even better results than the previous one, which will allow the 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.
CFD-FE Simulation of Wave Slamming on an Offshore Platform in Extreme Sea States
Authors: Kim Jang , Jang Hyunchul , Izarra Rafael , Martin David , Dalane Oddgeir 
Published: June 2014

Fluid flow and structural deformation of a floating platform during extreme wave slamming events are simulated by Computational Fluid Dynamics (CFD) and Finite Element Method (FEM) in coupled ways, in both model and full scale. The objective of the simulations is to verify correlation between slamming impact pressure on scaled platform model in the wave basin set up and full-scale platform in the real sea when the rigidity of the hull surface is considered. The slamming load and structural response simulated by CFD-FE analysis is first validated against analytic solutions and model tests for the following two cases:Wave slamming on rigid wall by breaking wave and water hammerDrop test of rigid and elastic structure on calm waterThe validated CFD-FE simulation set up is then applied to simulate wave slamming on three different realizations of a Spar hull structure:Rigid hull at model scaleRigid hull at full scalePressure panel at model scaleIn the CFD-FE modeling of the wave slamming at full- and model scale, compressibility of water/air and elasticity of the hull are properly modeled to simulate the difference between the hydroelastic effects at model- and full-scale set up. It has been found that the hydroelastic effect is minimal on full-scale Spar structure but can be significant on pressure panels at model scale. Further CFD investigations on other physical parameters that might affect the difference between wave slaming load at full- and model scale, such as surface tension, air entrapment and air-water mixture properties are made.
Fluid-Structure Interaction and Applications to Screening Pipeline Span VIV and Subsea Piping FIV
Authors: Pontaza J.P. 
Published: June 2014

Flow-induced vibrations (FIV) of subsea piping due to external flow (e.g., vortex-induced vibrations of pipeline spans) or internal flow (e.g., high velocity multiphase flow in subsea piping) may pose structural integrity concerns due to cyclic stressing at critical welds and, over time, a threat of fatigue failure. Assets in the design stage or in the operating stage which fail a screening based on published guidelines, may undergo a comprehensive screening based on numerical simulation. This paper gives an overview of such a screening methodology, based on computational fluid dynamics (CFD), structural finite element analysis (FEA), and associated fluid-structure interaction (FSI).
In the context of pipeline span VIV, seabed proximity effects and flow blockage effects may have a significant effect on the pipeline span response. High-level screenings based on DNV-RP-F105 may not account for these effects appropriately and result in overly conservative fatigue life estimates. We present a couple of application cases where the comprehensive screening makes evident these conservatisms.
In the context of FIV (due to internal flow) a high-level screening approach exists as part of the Energy Institute (EI) Guidelines on the Avoidance of Vibration Induced Fatigue Failure (AVIFF). However, the EI AVIFF guideline does not provide a framework for the direct estimation of vibration levels, stress levels, or fatigue life. The comprehensive screening methodology addresses this gap and is illustrated with an application case.
Vibration measurements and piping remediation are much more costly subsea than they are on topsides. Hence, advanced simulation techniques are valuable tools in determining the integrity status as well as the safe operating limits of subsea piping.