bluuebunny/crossref_metadata_2025_split huggingface dataset:
Support of Operational Decisions for Prelude’s Side-by-Side LNG Offloading
Authors: Auburtin Erwan , Miliante Thiago , van Haaften Ewoud , McPhail Finlay 
Published: November 2019

Abstract
Prelude floating liquefied natural gas (FLNG) facility reached a significant milestone in June 2018 when gas was introduced onboard for the first time as part of the facility startup process, loaded from an LNG Carrier (LNGC) moored in side-by-side (SBS) configuration. This first offshore LNG SBS operation allowed Prelude’s utilities to switch from running on diesel to running on gas.
SBS mooring is the base case configuration for offloading both LNG and Liquefied Petroleum Gas (LPG) into product carriers using Marine Loading Arms (MLA) once the Prelude FLNG facility is fully operational. These complex and weather sensitive operations are expected to take place on a weekly basis. This means critical decisions about weather-window and timing should be supported as much as possible by predictive analysis and modelling of forecast environment to reduce the risks.
There are multiple criteria for evaluating the operability of LNGC or LPGC SBS offloading. These criteria cover the various phases of an operation, such as personnel transfer to the visiting carrier, Terminal Team Leader (TTL) transfer, spool fitting and fender lowering, approach and mooring, connection and testing of the loading arms, ramp-up of product transfer, full rate cargo transfer, loading arm purging and recovery, de-berthing, and people and hardware recovery. The criteria have been tailored to be appropriate to the phase of the operation. They comprise both environment-based criteria (maximum acceptable wind and waves conditions), and criteria related to motion or mooring (carrier roll, MLA envelope, mooring line tension, fender deflection). Motion and mooring criteria are evaluated through dynamic time-domain simulations. This allows an accurate modelling of non-linear effects, including mooring characteristics and partially filled cargo tanks. Thrusters can be used to control Prelude FLNG facility position if needed. The required thruster force to maintain the selected heading is calculated with frequency-domain calculation for all possible headings.
This paper presents a visual reporting tool, developed by TechnipFMC in partnership with Shell. This tool has been used to support operational decisions during commissioning and startup, for SBS LNG and LPG import to Prelude FLNG facility. The daily reports used weather forecasts, in combination with numerical simulations, to predict the maximum motion and mooring criteria which contribute to determine both the timing and the decision to proceed with the operation. The format of the report has been designed to be user friendly for offshore operational staff, summarizing efficiently and in a visual manner the usage factors for each criterion separately. An overall operability is also presented for a quick overview. This paper also presents the details of numerical simulations, summarizes the different studies carried out to ensure the reliability of these simulations and discusses the possibilities for future development.
Plastic Accumulation in Front of a Plate in Cross Flow: Model Scale Test and CFD-DEM Modelling
Authors: Wrenger Hendrik , Sainte-Rose Bruno , Goniva Christoph , Hilbert Renan 
Published: November 2019

Abstract
Results of a flume experiment and numerical model of plastic accumulation in front of a plate are presented. The single phase CFD-DEM model formed a successful benchmark case to model plastic accumulation inside an ocean cleanup system.
A fixed wooden plate was placed in a steady cross flow and plastic was released upstream of it. We recorded the evolution of the plastic accumulation profiles under slowly increasing plastic load. Experimental parameters were the flow velocity, draft of the plate (varying the plate Froude number) as well as three different types of plastic particles. The accumulation of oil in front of barriers and parallels to the phenomena of plastic accumulation were reviewed.
As a second part of the project we used the open source CFD-DEM code CFDEM® to reproduce the flume experiment. It couples the discrete element method (DEM) software LIGGGHTS® and the open source computational fluid dynamics (CFD) software OpenFOAM®.
A linear relationship of the relative depth of the accumulation with the Froude number of the plate was found for a given type of particle and reproduced in the numerical model. We identified limitations of the experimental setup, calibration experiments and the single phase CFD-DEM approach and outlined the steps for further research.
Effect of Seabed Trenching on Holding Capacity of Suction Anchors in Deepwater Gulf of Guinea Clays: A Numerical Study
Authors: Castillo Garcia Pablo , Wallerand Regis , Hong Doan Dinh 
Published: November 2019

Abstract
In recent years, there has been an increasing issue of seabed trenches developing around mooring lines attached to suction anchors in West Africa, likely related to relatively large motions of the mooring lines. These trenches are recognised by means of numerical modelling and of centrifuge testing program as significant concern to the in-place holding capacity, the integrity of the anchor and the safety of the floating facility. Conservative trench geometries and complete absence of soil and of soil resistance in front of the anchor above the padeye depth (in the loading direction) were essential assumptions due to lack of observation. Results suggested that a reduction in holding capacity of 20% to 40% for typical mooring line load angles of 30° to 45° can be expected and that the presence of the trench does not affect the portion of holding capacity developed by passive suction at the pile tip. Nevertheless, recent survey data has evidenced a wedge of soil remaining within trenches in front of suction anchors leading to a new problem-solving approach. Consequently, this paper describes a Plaxis 3D Finite Element modelling in a parametric study as a reliable tool for the assessment of the holding capacity of the suction anchors in presence of seabed trench taking into account the presence of residual soil within the trench in front of the anchor pile. Analyses were performed under 30° inclined loading (actual case of taut deep water mooring systems) with various scenarios of trench shapes, padeye depths and anchor geometries in very soft highly plastic Gulf of Guinea clays. Thus, the consideration of the residual wedge of soil in front of the anchor leads to a much less reduction in holding capacity compared to initial studies done with too pessimistic assumptions on the final trench shape. In addition, this study aims at looking at changes in the pile geometry, including the position of the attachment point, to compensate the unavoidable formation of a trench for taut moorings.
Uncertainty Analysis in the Multi-Objective Optimization of Hydraulic Fracture
Authors: Baioco Juliana Souza , Jacob Breno Pinheiro , Mazadiego Luis Felipe 
Published: November 2019

Abstract
Unconventional reservoirs have become an important resource for hydrocarbons. The production of this type of reservoir is only feasible from massive stimulation. In this context, the study of hydraulic fracturing becomes important. The present work has the objective of evaluating the influence of reservoir parameters that are uncertain, in the optimization of hydraulic fracturing. The parameters that will be evaluated are: drainage radius, permeability, net-pay, temperature and pressure of the reservoir. The optimization model uses evolutionary algorithms to maximize the production of the fractured well and minimize the fracture cost.
New Engineering Approach for the Development and Demonstration of a Multi-Purpose Platform for the Blue Growth Economy
Authors: Lagasco F. , Collu M. , Mariotti A. , Safier E. , Arena F. , Atack T. , Brizzi G. , Tett P. , Santoro A. , Bourdier S. , Salcedo Fernandez F. , Muggiasca S. , Larrea I. 
Published: November 2019

Abstract
Aquaculture is currently the fastest growing food sector in the world and the open oceans are seen as one of the most likely areas for large-scale expansion [1], [2], [3]. The global demand for seafood is continuing to rise sharply, driven by both population growth and increased per capita consumption, whilst wild-capture fisheries are constrained in their potential to produce more seafood. A recently funded EC project, the Blue Growth Farm – BGF (GA n. 774426, 1st June 2018 – 30th September 2021) aims at contributing to this world need with an original solution. The Blue Growth Farm proposes an efficient, cost-competitive and environmentally friendly multi-purpose offshore farm concept. It is based on a modular floating structure, moored to the seabed, meeting requirements of efficiency, cost-competitiveness and environmental friendless, where automated aquaculture and renewable energy production systems are integrated and engineered for profitable applications in the open sea. In the present paper, the overall engineering approach developed to carry out the research work is presented, described and justified. Different technical and scientific challenges are addressed through an integrated industrial engineering design approach, where all disciplines are tuned to achieve the Blue Growth Farm main targets. These are represented by: i) guaranteeing expected nominal fish production thanks to advanced automation and remote control capabilities; ii) minimizing the pollution introduced at marine ecosystem level when exploiting the marine natural resources, whilst increasing the social acceptance and users community agreement; iii) maximizing the electricity production in the Blue Growth Farm potential installation area ecosystem to provide energy supply to the on-board electrical equipment and to dispatch the extra produced electric energy to the land network. Preliminary engineering design results are promising to demonstrate effective increase of safety and efficiency by reducing on-board human effort and consequently risks at offshore, thus to make commercial-scale open ocean farming a reality.
The present paper introduces overall concepts and design methodology whilst other companion works submitted at OMAE2019 [4], [5], [6] provide insight of specific aspects of the Blue Growth Farm project elaborated during the first six months activity.
Influence of Different Pile Installation Methods on Dense Sand
Authors: Spill Severin , Quiroz Tulio , Foglia Aligi 
Published: November 2019

Abstract
A current investigation subject of geotechnical modelling is the realistic representation of the installation process of offshore piles and its influences on the surrounding soil. Depending on the soil conditions piles can be installed with different installation technologies like impact driving, vibratory driving or jacking. The soil disturbances produced as a consequence of the pile installation affect the pile capacity. The dimension of the affected region depends on the installation process itself and its parameters as well as the soil initial state and the pile geometry. Currently, there are no general approaches which can predict the effects of pile installation on the soil conditions. In this contribution a brief summary of published data describing installation effects for impact driven, vibratory driven and jacked piles is given. Secondly, the influences of different pile installation methods on the surrounding soil are presented based on experimental results for non-cohesive soils from various projects. These will be analyzed by means of a comparison of dynamic probe light (DPL) and cone penetration tests (CPT) executed before and after the pile installations. Additionally the area of influence will be quantified with respect to their relative distance to the pile axis. Finally, based on these results recommendations for future works will be given.
Assessment of LNG Pump Tower Loads
Authors: Thome Michael , Neugebauer Jens , el Moctar Ould 
Published: November 2019

Abstract
The assessment of design loads acting on Liquefied Natural Gas (LNG) pump tower are widely based on Morison equation. However, the Morison equation lacks consideration of transverse flow, impact loads and the interaction between fluid and structure. Studies dealing with a direct simulation of LNG pump tower loads by means of Computational Fluid Dynamics (CFD), which can cover the aforementioned effects, are currently not available.
A comparative numerical study on LNG pump tower loads is presented in this paper focusing on the following two questions: Are impact loads relevant for the structural design of LNG pump towers? In which way does the fluid-structure interaction influence the loads?
Numerical simulations of the multiphase problem were conducted using field methods. Firstly, Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations, extended by the Volume of Fluid (VoF) approach were used to simulate the flow inside a three-dimensional LNG tank in model scale without tower structure. The results were used to validate the numerical model against model tests. Motion periods and amplitudes were systematically varied. Velocities and accelerations along the positions of the main structural members of the pump tower were extracted and used as input data for load approximations with the Morison equation.
Morison equation, URANS and Delayed Detached Eddy Simulation (DDES) computed tower loads were compared. Time histories as well as statistically processed data were used. Global loads acting on the full (with tower structure) and simplified structure (no tower structure, but using Morison equation) are in the same order of magnitude. However, their time evolution is different, especially at peaks, which is considered significant for the structural design.
Thermal and Mechanical Coupled Analysis of Marine Composite Cryogenic Pipeline
Authors: Hu Haitao , Yan Jun , Zhou Baoshun , Yang Zhixun , Yang Liang , Fan Jiakun 
Published: November 2019

Abstract
Marine composite cryogenic pipeline is one of the key equipment for offshore gas explorations, which is mainly used in the transmission of liquefied natural gas. Due to the harsh marine environment and extreme temperature of transmission medium, the marine composite cryogenic pipeline needs to bear both the tensile and bending loads caused by marine environments and the ultra-low temperature load caused by transmission medium. Due to the extremely low temperature of liquefied natural gas, about −163 °C, the structure and the composed material of cryogenic pipelines will be faced greatly challenges. Previous studies have considered mechanical properties or temperature loading separately. In this research, the structural performance of the marine composite cryogenic pipeline under the combined action of mechanical loads and thermo-load is studied with numerical methods. The framework of the coupled mechanical and thermo-analysis for the structure of composite cryogenic pipeline is established. The numerical results show that the temperature distribution has great impacts on the structural responses of the cryogenic pipeline. The coupled mechanical and thermo analysis of the cryogenic pipeline is proved to be necessary. The established method and framework provide a reference for the engineering design and application of the marine composite cryogenic pipeline.
Numerical Simulation of Trim Optimization on Resistance Performance Based on CFD Method
Authors: Duan Wenyang , Zhang Hongsen , Huang Limin , Liu Jianyu , Shao Wenbo , Cao Guanzhou , Shi Zhang 
Published: November 2019

Abstract
In response to the gradually stringent carbon emission requirements of the International Maritime Organization (IMO), the energy-saving methods of the shipping industry have received increasing attention. Today how to reduce fuel consumptions so as to lower carbon emissions to improve the economic and environmental benefits of ships has become a hot topic. As one of the most easily implemented energy-saving methods, trim optimization has caught more and more researchers’ eyes.
In this paper, a commercial CFD software STAR-CCM+ was adopted to analyze the influence of trim on the resistance performance of VLCC ship mainly with fixed model method under various typical conditions of the design draft and the ballast draft respectively. The grid convergence was studied at the design draft and the typical numerical simulations were verified by the experimental results before carrying out various numerical simulations of trim optimization. Seven different kinds of trim conditions, which correspond to the changing process of the full scale ship from trimming by stern 4m to bow 4m, were simulated with 3 different speeds of design draft and ballast draft. The changes of total resistance, frictional resistance and residual resistance were analyzed to explore the effect of trims on the ship’s resistance. The variation of ship’s wetted surface area and waterplane area under different trim angles were studied. It was found that under the condition of low Froude number, both the simulation of free trim and sink method and the fixed model method can achieve good accuracy with the method of fixed model reducing the simulation time obviously. Both conditions of the design draft and ballast draft had a certain reduction effect of total resistance for trimming by bow properly, of which the change of frictional resistance is dominant in the decrease of total resistance at design draft while the change of residual resistance is the main cause at ballast draft. The optimum trims were found and the optimal total resistance reduction effects were evaluated. The optimal total resistance reduction effect increased with speed whether at the design or the ballast draft and the reduction effects were more obvious at ballast draft. Meanwhile, it was found that the changes of wetted surface area and the waterplane area with different trims were close to the variation tendency of the frictional resistance.
Study of the Influence of Controlled Axial Oscillations of pVARD on Generating Downhole Dynamic WOB and Improving Coring and Drilling Performance in Shale
Authors: Abugharara Abdelsalam N. , Molgaard John , Hurich Charles A. , Butt Stephen D. 
Published: November 2019

Abstract
This work concentrates on the investigation of enhancing drilling performance through increasing drilling rate of penetration (ROP) by using a passive vibration assisted rotary drilling (pVARD) tool. It also involves analysis of how ROP was significantly increased when drilling using pVARD compared to drilling using conventional system “rigid” using coring and drilling in shale rocks. The apparatus used was a fully instrument laboratory scale rig and the bits were dual-cutter polycrystalline diamond compact (PDC) bit for drilling and diamond impregnated coring bit for coring. The flow rate was constant of (7 litter / min) using clean water at atmospheric pressure. In addition, for accuracy data recording, a data acquisition system (DAQ-Sys) using a LabVIEW software was utilized to record data at 1000HZ sampling rate. The output drilling parameters involved in the analysis included operational rpm, torque (TRQ), and ROP. All the output-drilling parameters were analyzed with relation to downhole dynamic weight on bit (DDWOB). The result of this work explained how pVARD can increase the DDWOB and improve ROP. The result also demonstrated generating a balanced and concentric increase in DDWOB and minimizing the wide-range fluctuation of DDWOB generated in rigid drilling, particularly at high DDWOB.
A Field Study on the Marine Environmental Impact of the Drilling Fluid’s Discharge
Authors: Jiang Meirong , He Xiaohan 
Published: November 2019

Abstract
In view of the inadequate research for the far-field effect of the drilling fluid’s discharge, a field study has been carried out to investigate the discharge impacts of a water-based fluid on the marine environment. According to an offshore oilfield exploitation project in Bohai Sea, the waste drilling fluid is discharged from pipes pointed vertically downward into the ocean. A relative large tracking range at distances up to 2,000 meters from the discharge point is determined in the light of the results from the previous study and the environment impact assessment report. The concentration of the suspended solids in different time, distances and depths are tracked and monitored by the field measurement. The suspended solids concentration and their distribution characteristics are analyzed from the different stations during the discharge and recovery phase and the contrast stations. From this field monitoring of the drilling fluid’s discharge, the average concentrations for the surface, middle and bottom layers are evenly distributed along the water depth. The maximum concentration of suspended solids monitored in the discharge and recovery period are smaller than that in the contrast station. Meanwhile, the average monitoring concentrations of suspended solids in the surface, middle and bottom layers during the discharge and recovery period are also all lower than the corresponding ones from the contrast station. Within the range of this monitoring, the discharged drilling fluid has been rapidly diluted and spread, and there is no phenomenon for the suspended solids concentration in excess of the primary standard. Therefore the monitoring results in the discharge and recovery period can be attributed to the natural fluctuation of the background value. In another word, the influence range of the drilling fluid’s discharge is no more than 200 meters under the current condition. This study can provide some practical reference for the environmental evaluation of the drilling fluid’s discharge in the offshore petroleum engineering.
Experimental and Numerical Study of Horizontal Wave Impact Loads for a Semi-Submersible Drilling Unit
Authors: Kim Joo-Sung , Yoo Seon Oh , Kim Hyun Joe , Lee Jong Hun , Han So Lyoung , Lee Dong Yeon 
Published: November 2019

Abstract
A semi-submersible drilling unit model was tested to estimate horizontal wave impact loads on vertical side of deckbox following the procedure recommended by DNVGL OTG-14. The present model test data show that there is clear difference in the relationships between upwell and horizontal wave impact pressure between near column/pontoon and around centerline. Near column and pontoon, not only is the maximum pressure much lower but the pressure increases more smoothly to its maximum value, compared to those of centerline.
CFD simulations with focusing breaking waves have been made to examine the effect of wave-body interaction on horizontal wave impact on deck-box. The present CFD simulation results clearly show that the flows in front of column are strongly accelerated in vertical direction by blocking effect of column and pontoon, eventually producing strong run-up jets. The run-up jets in the present study are so strong that the direct impact of the incoming breaker on the wall does not occur, which leads to much smaller peak pressures, compared to those of centerline.