bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydraulic Behavior in Cased and Open Hole Sections in Highly Deviated Wellbores
Authors: Ytrehus Jan David , Lund Bjørnar , Taghipour Ali , Kosberg Birgitte Ruud , Carazza Luca , Gyland Knud Richard , Saasen Arild 
Published: November 2019

Abstract
In this paper we present results from flow loop experiments with an oil-based drilling fluid with micronized barite as weight materials. The use of micronized barite allows using lower viscosity drilling fluid, providing non-laminar flow, which is advantageous for particle transport in near-horizontal sections. While transition to turbulence and turbulent flow of non-Newtonian fluids has been well studied both theoretically and experimentally, there are very few published results on the effect of wellbore wall properties on flow regime transition and turbulence. This is relevant because horizontal sections are often open-hole with less well-defined surfaces than a steel casing surface. We have conducted a series of flow experiments with and without cuttings size particles in a 10 m long annular test section using steel and concrete material to represent the wellbore wall of a cased and open hole section. In both cases the annulus was formed by a freely rotating steel pipe of 2” outer diameter inside a 4” diameter wellbore. Experiments were conducted at 48°, 60° and 90° wellbore inclination from vertical. The two materials result in different hydraulic behaviour without particles with stronger turbulence when using concrete wellbore wall material than when using steel casing. While there is negligible difference at low flow rates, at 0.8 m/s and below, there is an increasing difference as the flow rate increases and becomes transitional to turbulence. Hole cleaning is found to differ dependent on the wall material. However, the effect on hole cleaning is less clear than for the pressure loss.
Assessment of Weld Overlays in Cladded Piping Systems With Varied Thicknesses
Authors: Kogo Bridget , Wang Bin , Wrobel Luiz , Chizari Mahmoud 
Published: November 2019

Abstract
This paper continues the research previously done by authors on computer simulation of the dissimilar welded joints with varying clad thicknesses using numerical methods. For different cladding thicknesses comprising of stainless steel and mild steel, stress curves have been generated. The welding of the two dissimilar materials has been carried out in-house with the aid of a tungsten arc weld with dynamic measurement of the temperature profile in vicinity of the welding track using high temperature thermocouples. Comparison of the experimentally measured stresses from literature versus the simulation results shows close agreement.
Gap Resonance of Fixed Floating Multi Caissons
Authors: Chen Limin , He Guanghua , Bingham Harry B. , Shao Yanlin 
Published: November 2019

Abstract
Generally, numerous marine and offshore structures are composed of a number of modules which introduce narrow gaps between the multi-modules arranged side by side. The interaction between water waves and floating structures excites complex wave runup in the gaps and wave forces on the adjacent modules. In this study, free surface oscillations in twin narrow gaps between identical floating rectangular boxes are investigated by establishing a 2D viscous flow numerical wave tank based on a Constrained Interpolation Profile (CIP) method. The Tangent of Hyperbola for INterface Capturing (THINC) method is employed to capture the free surface. The rigid floating bodies are treated by a Virtual Particle Method (VPM). The incident waves are generated by an internal wave maker. For the fixed module cases, the computational results of wave height in narrow gaps are found in good coincidence with the available experimental measurements, especially for the resonant frequencies. The wave forces on the floating bodies are calculated numerically. The characteristic response of wave forces on the leading and rear bodies are consistent with the free surface elevations in the corresponding narrow gaps. With shallow draft, the gap resonance occurs at higher wave number.
Multiphase Flow Induced Forces on Bend Structures
Authors: Belfroid S. P. C. , Gonzalez-Diez Nestor , Pereboom H. , Tümer C. 
Published: November 2019

Abstract
Multiphase conditions can lead to high vibration in flexible pipe systems due to high dynamic flow induced forces. To better model the dynamic forces, large scale 6” air-water, near-atmospheric experiments have been done with different bend radii and upstream configurations. This paper gives an overview of the obtained results with respect to the overall dynamic force and force power spectral density description parameters. Scaling rules based on these experiments are given.
Field Trial of Vortex-Induced Vibration Suppression Technology for Drilling Riser Buoyancy
Authors: Kurts Phillip P. , Marcollo Hayden , Kilner Andrew A. , Johnstone Daniel , Potts Andrew E. , Pezet Peter , Hill Tricia 
Published: November 2019

Abstract
Instrumented field trials of Longitudinally Grooved Suppression (LGS) VIV suppression buoyancy modules have been completed on deep water drilling risers in the Gulf of Mexico. The field trials were used to validate the performance of the technology, which had previously been evaluated using prototype scale model tests. The measured riser responses over two drilling campaigns spanning more than six months were compared with each other and the outputs of computational riser modeling to validate the hydrodynamic parameter set derived through scale model tests and provide validated assessments of the suppression technology performance.
The measured response of drilling risers equipped with LGS buoyancy has been compared with a publicly available dataset for the VIV response of a conventionally buoyed riser, showing reduced VIV response in agreement with model test results. Measured flex joint angles, current profiles and riser accelerations were used to validate the hydrodynamic parameters used in numerical riser analysis. Using the validated hydrodynamic parameters, the VIV and drag suppression performance was demonstrated by comparison with the model predictions for risers equipped with conventional buoyancy modules. Eddy current occurrence statistics for a location in the Gulf of Mexico were used to calculate the expected annual operability performance for both configurations.
For the base case parameters, 12 days of annual operability improvement was predicted when using LGS buoyancy modules. A sensitivity study determined the effect of varying analysis assumptions on the predicted operability improvements. Measured current data from 2014 was also used to determine the operability benefits which could be realized within a year in which severe eddy current activity occurred.
The analysis performed serves to validate the previous laboratory tests as well as answer questions about the applicability of high Reynolds Number test results to VIV suppression devices in the field. The use of previously validated testing and analysis methods is shown to provide reliable estimates of suppression technology performance which are borne out by testing in the field. This paper presents the first published field trial of shaped buoyancy type VIV suppression, a group of technologies which have until now only been demonstrated using scale model tests and Computational Fluid Dynamics simulations.
Wave Propagation in CFD-Based Numerical Wave Tank
Authors: Kim Jang , Baquet Aldric , Jang Hyunchul 
Published: November 2019

Abstract
A heuristic approach to investigate the characteristics of the numerical waves propagating in various CFD-based NWT set ups is proposed to develop an optimal grid system for a numerical wave tank. Linear dispersion relations of the waves in a Cartesian grid system are derived analytically. The analytic results lead to an optimal grid aspect ratio for the best dispersion approximation. Extensions of the analytic approach to determine an optimal set up of the grid system of CFD-based NWT are discussed. A roadmap to develop CFD modeling practices based on these heuristic approaches and further numerical verification is proposed for the on-going industry efforts to develop the guidelines for numerical wave tanks, such as the Joint Industry Project on “Reproducible CFD Modeling Practices for Offshore Applications”.
Study on the Multi-Body Dynamic Characteristics of FPSO Soft Yoke Mooring System Based on Symplectic Algorithm
Authors: Wu Wenhua , Lyu Baicheng , Yao Ji , Yue Qianjin , Yantao Zhang , Guo Xinglin 
Published: November 2019

Abstract
The soft yoke single-point mooring (SYMS) system is the main mooring approach for the floating production storage and offloading (FPSO) unit. As a typical multi-rigid-body system, a SYMS consists of the single-point turret, yoke, mooring legs, and mooring support. It releases the rotational degrees of freedom of an FPSO through the combined effects of multiple joint structures, so as to deliver the weather-vane effect of the FPSO. In this paper, a multi-body dynamics model of the soft yoke mooring system was established. To deal with the difficult integration in the process of solving differential-algebraic equations, a symplectic numerical integration method was proposed on the basis of the Zu Chongzhi method. The proposed solution format had simple symplectic property automatically satisfying the Hamilton system, as well as a high accuracy in solving nonlinear systems. The measured data of the FPSO’s six degrees of freedom (6DoF) under two different sea conditions were selected, and the mooring restoring force of the SYMS was calculated. The calculated results showed that the symplectic solution method could the actual stress state of the structures with more obvious dynamic characteristics. Furthermore, the displacement and stress state of the single-body structures, such as the mooring legs and yoke, and the analysis result could comprehensively evaluate the overall working state of the SYMS.
Tension Based Heading Control Strategy of the Arctic FPSO With DP Assisted Mooring System
Authors: Lee Jaeyong , Choi Sol-Mi , Lee Seung Jae , Jung Kwang Hyo 
Published: November 2019

Abstract
For offshore plants operating in the Arctic region, it is important to reflect the motion characteristics of the ice in the design stage. When the ice load is applied, the platform should rotate in the direction to reduce the tension acting on the mooring system using the DP system. However, it is very difficult to conduct the simulation by predicting the size and direction of the ice. This paper presents a heading control strategy to reduce the ice load acting on the arctic production platforms equipped with DP (Dynamic Positioning) Assisted Mooring System. In order to save computation time, grids are created in the operating area and the size of the tension acting on each grid is calculated considering the current position, the current tension, and the rate of change of tension. Based on the tension information, target heading angle is assigned and the platform is rotated with DP module. Developed process is validated through the simulation.
On the Estimation and Application of Directional Design Criteria
Authors: Feld Graham , Jonathan Philip , Randell David 
Published: November 2019

Abstract
This article discusses the estimation of directional metocean design criteria for engineering applications. We provide a summary of current code recommendations relating to directional design criteria and illustrate conceptually and mathematically some of the difficulties of their derivation. We also discuss the application of directional criteria for the specific examples of Code Check and Pushover analyses for fixed structures and jack-up rigs.
Mechanical Friction in Well Construction and Laboratory Testing of Friction Coefficients
Authors: Ghaedi Parisa , Khalifeh Mahmoud , Saasen Arild , Hodne Helge , Omland Tor H. , Shoghl Farzad 
Published: November 2019

Abstract
A new device for measuring the lubricity of drilling fluids for controlling the mechanical friction is developed. This is able to measure mechanical friction at temperatures between room temperature and 200°C and at pressures in the range of atmospheric to 20 000 psi. The effects of lubricants on mechanical friction is outlined. Different types of available test instruments are reviewed. These instruments include both commercial equipment and special designed equipment. In addition, the effect of pressure and temperature as well as their combined effect on the friction coefficient of deionized water, mineral oil and oil-based mud (OBM) have been investigated as initial test of the developed instrument. Our initial results show that friction coefficient increases with pressure increase for the mineral oil and OBM, at 25°C. However, when deionized water was used as lubricant, the friction coefficient decreased when pressure was increased.
Assessment of the Carcass Role in Designing Deepwater Riser Connectors
Authors: Saneian Mohsen , Bai Yong 
Published: November 2019

Abstract
Technically, in deep water, the most challenging task is the end-fitting design of pipes. This connector has two main functions: It ensures sealing of the pipe fluid and transfers the loads from the pipe to the connecting system unit. High pressure and harsh environment condition raise the pressure on the connector; therefore, this pressure should be endured by a segment which is the carcass. Carcass holder and installation rings are components of the connectors in termination of the carcass layer. This paper assesses the role of the carcass in a sealing system of riser connectors. The sealing method is based on dividing the termination of risers into two devices; inner liner that is the mechanical restraint on the polymer barrier, and the seal system that is applied to seal the fluid of riser. This seal system includes many ring joint gaskets separated by metallic rings, and they should be placed on the carcass.
Experimental and Numerical Study of Motion of Rotating Drill Pipe Owing to Magnus Effect
Authors: Inoue Tomoya , Suzuki Hiroyoshi , Katsui Tokihiro , Tsuchiya Keita , Notani Yusuke 
Published: November 2019

Abstract
During riserless drilling operations conducted in some scientific drillings and the initial stages of all oil and gas drilling operations, drill pipe motions such as vortex induced vibration, whirl motion, and motion due to the Magnus effect are generated. The last motion represents an interesting and important phenomenon that generates a lift force in addition to a drag force due to the ocean current and the rotation of the drill pipe. Accordingly, this study focuses on the drill pipe motions owing to the Magnus effect.
An analytical model of a drill pipe was established by applying an absolute nodal coordinate formulation (ANCF) that can capture the behavior of a relatively flexible and long pipe, such as a drill pipe. The lifting and drag forces are calculated using computational fluid dynamics (CFD), and the lift and drag coefficients are calculated for several different drill pipe rotational velocities and ocean current velocities.
A series of model experiments were conducted in a towing tank, with changing water flow velocities and rotational speed of the drill pipe model to observe the corresponding changes in the Magnus effect and to measure the resulting drill pipe motions. Additionally, the resulting drag and lift forces were measured. It was observed from the experiments that the motions in the cross-flow direction increased as the rotational speed of the drill pipe model increased, and that the lifting force increased as the rotational speed increased.
The drill pipe motions were then simulated using a previously established analytical model and the results of the CFD simulations. The results of the simulations were evaluated against the results of the experiments, and reasons for observed discrepancies are discussed.
Integrated Acoustic Communication and Positioning System Between an Autonomous Surface Vehicle and Autonomous Underwater Vehicles
Authors: Watanabe Yoshitaka , Meguro Koji , Deguchi Mitsuyasu , Kida Yukihiro , Shimura Takuya 
Published: November 2019

Abstract
In underwater observation using an autonomous underwater vehicle (AUV), a support vessel typically monitors the AUV to support the observation. In order to make the AUV operation more efficient, an autonomous surface vehicle (ASV) and an acoustic multi-access communication and positioning system have developed.
The developed acoustic system achieves multi-access with frequency division multiple access (FDMA) method, and the ASV can monitor up to three AUVs simultaneously. Positioning is performed with super short baseline (SSBL) method. The acoustic device has operation mode in which positioning and communication functions are integrated to achieve efficient uplink and accurate downlink simultaneously.
Two observation operations were conducted successfully. In one of those, the ASV communicated with two types of AUVs during observation in 1250m water depth, then multiple access were achieved. Even nadir angle for one AUV became almost 40 degrees, the acoustic communication was performed. In another observation, two cruising AUVs were operated with a vessel and the ASV in 1500m water depth. The ASV monitored one AUV. Condition in case the device is equipped on small body of the ASV was evaluated. The communication was performed in this depth in severe condition. Furthermore integrated sequence of positioning and communication was successfully performed. Requirement in next phase, in which operation depth and number of multiple access are increased, is discussed.
A New Method for Deriving Soliton Design Criteria
Authors: Jeans Gus , Jones Oliver , Zhang Michael , Jackson Christopher R. , Stashchuk Nataliya , Osborne Alfred R. , Petersen Ole Svenstrup , da Silva José 
Published: November 2019

Abstract
A new method for deriving extreme soliton current criteria for offshore engineering applications is described. The primary data source was site specific measurement close to the continental shelf break where metocean criteria were required. A dedicated oceanographic mooring was designed to quantify solitons, with rapidly sampled measurement of seawater temperature and velocities through the vertical.
As described in two previous OMAE papers, quantification of soliton velocity profiles was achieved via temperature measurement and theory, with measured velocities playing a secondary role in critical validation. The previous methodology was extended in the present study, with separate contributions quantified from variations in soliton amplitude and water column density structure.
The nonlinear Fourier techniques first described in OMAE 2017 were again used to reduce uncertainty in estimates of extreme soliton amplitude. In a new development, the long-term distribution of the density structure contribution was quantified using a calibrated hindcast of seawater temperature.
Extreme conditions were defined at the boundary of a MITgcm model domain. This sophisticated model was then used to estimate extreme soliton velocities, through the water column and a few metres above the seabed, at a wide range of shallower target locations.
A Hybrid Methodology for Maritime Accident Analysis: The Case of Ship Collision
Authors: Bowo Ludfi Pratiwi , Prilana Ramdhani Eka , Furusho Masao 
Published: November 2019

Abstract
Human error is recognized as the most common factor that causes maritime accidents. Human Error Assessment and Reduction Technique (HEART) as a Human Reliability Assessment (HRA) has been widely applied in various industries. However, in the maritime industry, machine, media, and management are also considered as factors that can strongly affect human behavior, judgment, and other human elements. These factors are particularly relevant for bridge resource management that perform the task of maintaining a proper look-out. Therefore, this study considers the effect of those factors integrated with 4M (man, machine, media, management) factors. The study was conducted with 37 collisions accident reports from 2007–2017, using data from the NTSB and TSB-Canada. There are 229 Error Producing Condition (EPC) found in this study. The classification of the EPC to the 4M conducted in this study.
Random Combination Factors for Still Water and Wave Bending Moments
Authors: Huang Wenbo 
Published: November 2019

Abstract
Based on the extreme value of the primary loads of ship hull girder instead of characteristic values, the more reasonable load combination factors are defined. In order to evaluate the random variation of newly defined load combination factors, based on Ferry-Berges & Castanheta (FBC) and Poisson square wave models, the still water bending moments (SWBM), vertical wave bending moments (VWBM) and their combined processes are simulated to get the random realizations of load combination factors. The statistical analysis results show that the load combination factors take the value of 1 with the highest probability and can be well fitted by the Weibull distribution. Such information should be incorporated appropriately in the reliability analysis of ship hull girder.
Understanding the Phenomenon of Dissolved Gas Migration of Gas in Riser During Drilling Operations
Authors: Nahri Syed Y. , Chen Yuanhang , Williams Wesley , Santos Otto , Thibodeaux Louis , Zhu Jianjun 
Published: November 2019

Abstract
The prevention and control of gas kicks is a major concern in the petroleum industry during deepwater drilling operations. The problem is further aggravated when dealing with synthetic and oil-based muds (SOBM and OBM) that can dissolve a gas influx entering the wellbore. Due to the solubility of formation gases in drilling fluids, the gas cut mud resulting from gas absorption has a density lower than that of overlaying unsaturated drilling fluid. Lab scale experimental tests were conducted in order to understand whether buoyancy-induced convection and diffusion attribute to mass transfer of a dissolved influx. Experiments were performed on a low-pressure mass transfer apparatus using carbon-dioxide (CO2) and mineral oil to study the extent of mass transfer due to buoyancy induced convective flow and diffusion. Measurements were made on the axial distance travelled by the dissolved carbon dioxide and gas concentration over the length of a pipe by measuring the mass of gas accumulated in different test sections of the experimental apparatus. This arises due to a concentration gradient developed when contaminated fluid comes in contact with a fresh column of drilling fluid. Experimentally obtained measurements made on the mass transfer coefficient are used to tune simulations carried out using a computational fluid dynamic (CFD) software — ANSYS Fluent. This enables us to replicate field scenarios to study the extent of well control issues that could arise when a gas influx enters the wellbore, even when circulation has ceased. Results obtained here can be used as a base case to understand a similar phenomenon occurring when extended to other fluid systems such as that of a natural gas influx in synthetic oil-based drilling fluids.