bluuebunny/crossref_metadata_2025_split huggingface dataset:
CFD Gas Explosion Simulation on LNG-Fueled Ship
Authors: Nubli Haris , Sohn Jung Min 
Published: October 2021

Abstract
The International Maritime Organization (IMO) has issued the regulation of the Emission Control Area (ECA). This area was designated to control the air pollutant which emitted by conventional fuel from a ship. Thus, LNG fuel could be an alternative fuel to deal with a new regulation. However, the utilization of LNG fuel in the ship should be proven for its safety and reliability.
The scope of this work was to capture the blast overpressure as an accidental load. The open-deck fuel gas supply system (FGSS) of the hypothetical Oil Tanker was used as a target for the explosion model. The parameters of the scenarios consisted of the gas cloud size and gas cloud center of gravity in X, Y, and Z directions. Each parameter contains a likelihood, and it should be converted as probability density functions (PDF). Thus, it can be utilized to generate 50 scenarios by Latin Hypercube sampling.
This research used the ExSim CFD (Computational Fluid Dynamics) code to simulate a gas explosion. The grid convergence and software validation were also conducted to understand the software performance. Finally, the overpressure and gas explosion frequency from scenarios could be utilized to determine the exceedance frequency diagram. This diagram could be used as a prediction of the gas explosion on the LNG-fueled ship.
Numerical Simulation of the Fixed Barge Barge Interaction Under Irregular Wave Using HOS-StarCCM+ Coupling Tool With Experiment Validation
Authors: Zhang Yali , Xu Haihua , Santo Harrif , Chua Kie Hian , Law Yun Zhi , Chan Eng Soon 
Published: October 2021

Abstract
The interaction between two side-by-side floating vessels has been a subject of interest in recent years due floating liquefied natural gas (FLNG) developments. The safety and operability of these facilities are affected by the free-surface elevation in the narrow gap between the two vessels as well as the relative motions between the vessels. It is common practice in the industry to use potential flow models to estimate the free-surface responses in the gap under various wave conditions. However, it is well-known that any potential flow models require calibration of viscous damping, and model tests are carried out to provide a platform to calibrate the potential flow models.
To improve beyond the potential flow models, Computational Fluid Dynamics (CFD) models will be required. However, the large computational efforts required render the conventional CFD approaches impractical for simulations of wave-structure interactions over a long duration. In this paper, a developed coupled solver between potential flow and Computational Fluid Dynamics (CFD) model is presented. The potential flow model is based on High-Order Spectral method (HOS), while the CFD model is based on fully nonlinear, viscous and two phase StarCCM+ solver. The coupling is achieved using a forcing zone to blend the outputs from the HOS into the StarCCM+ solver. Thus, the efficient nonlinear long time simulation of arbitrary input wave spectrum by HOS can be transferred to the CFD domain, which can reduce the computational domain and simulation time.
In this paper, we make reference to the model experiments conducted by Chua et al. (2018), which consist of two identical side-by-side barges of 280 m (length) × 46 m (breadth) × 16.5 m (draught) tested in regular and irregular wave conditions. Our intention is to numerically reproduce the irregular wave conditions and the resulting barge-barge interactions. We first simulate the actual irregular wave conditions based on wave elevations measured by the wave probes using the HOS solver. The outputs are subsequently transferred to the CFD solver through a forcing zone in a 2D computational domain for comparison of the irregular wave conditions without the barges present. Subsequently, a 3D computational domain is set up in the CFD with fixed side-by-side barges modelled, and the interaction under irregular waves is simulated and compared with the experiments. We will demonstrate the applicability of the HOS-StarCCM+ coupling tool in terms of accuracy, efficiency as well as verification and validation of the results.
Algorithms and Models for Smart Well Planning With Emphasis on Trajectory Optimization
Authors: Wiktorski Ekaterina , Sui Dan 
Published: October 2021

Abstract
Well planning is a time-demanding procedure, which integrates knowledge and experience of various field professionals, as drilling engineers, pipe manufacturers, drilling mud specialists, geologists, etc. According to OG21 report (1), time spent for planning a well is on average 2–3 months. Drilling engineers have to design a well at minimum costs maintaining wellbore integrity at any time. The wellbore should also allow for maximum production from the reservoir and minimum tortuosity for successful casing running and completion. Fortunately, in the well-explored geological areas, where stratigraphic sequences and corresponding geopressures are known, the main objective can be narrowed down to optimal trajectory design. Optimal wellbore trajectory considers at least three criteria: shortest possible path, collision avoidance and longest possible contact with reservoir.
Due to large number of modules involved, well planning requires a holistic approach. At the same time, due to complex interaction between the modules and respective physical models, this task implicates a high level of precision. This paper presents a development of an in-house well planning simulator, which integrates all essential well planning modules in a smart way. Central part of the simulator is represented by a trajectory planning and optimization module, which is based on minimization of wellbore length and dogleg severity. Constraints related to anticollision are also included.
Introduction of smart optimization techniques for wellbore trajectory has a real potential of saving time and efforts by providing engineers with multiple options, which satisfy the aforementioned constraints. Our ultimate goal is to automate wellbore planning to the largest possible extent by developing smart optimizers for other vital modules within the well planning simulator.
Validation of a Numerical Model for the Investigation of Tension Leg Platforms With Marine Energy Application Using REEF3D
Authors: Windt Christian , Goseberg Nils , Martin Tobias , Bihs Hans 
Published: October 2021

Abstract
Exploiting the offshore wind resources using floating offshore wind systems at sites with deep water depths requires advanced knowledge of the system behaviour, including the hydro-, areo-, and mooring dynamics. To that end, high-fidelity numerical modelling tools, based on Computational Fluid Dynamics, can support the research and development of floating offshore wind systems by providing high-resolution data sets.
This paper presents the first steps towards the numerical modelling of tension leg platforms for floating offshore wind applications using the open-source Computational Fluid Dynamics toolbox REEF3D. The numerical model of a taut-moored structure is validated against experimental reference data. Results from wave-only test cases highlight the simplicity and effectiveness of the wave generation method, implemented in REEF3D. For the considered wave-structure interaction cases, deviations between the experimental and numerical data can be observed for the surge and pitch displacements, while the heave displacement and the mooring forces are capture with sufficient accuracy. Overall, the numerical results indicate high potential of REEF3D to be used for the modelling of floating offshore wind systems.
Fatigue Assessment of Mooring Chain Considering the Effects Of Mean Load and Corrosion
Authors: Lone Erling N. , Sauder Thomas , Larsen Kjell , Leira Bernt J. 
Published: October 2021

Abstract
Results from full scale fatigue tests of offshore mooring chains performed in recent years have revealed considerable influence of both mean load and corrosion condition on the fatigue capacity. It has been shown that a reduction of the mean load gives an increase in fatigue life, whereas the corrosion experienced by used chains have a significant negative impact. Neither of these effects are properly addressed by current S-N design curves or design practice.
This paper suggests an extended S-N curve formulation, that includes the effects of mean load and corrosion condition. The parameters of the extended formulation are estimated empirically from mooring chain test data that includes new and used chains, with various mean loads and with different degrees of corrosion. The fitted capacity model is then used for fatigue calculation for the mooring system of a semi-submersible, showing the importance of using realistic mean loads and mooring chain corrosion in fatigue assessments.
Sensitivity of a Floating Bridge Global Responses to Different Wave Drift Force Models
Authors: Silva de Souza Carlos Eduardo , Fonseca Nuno , Kvittem Marit Irene 
Published: October 2021

Abstract
Floating bridges are a promising solution for replacing ferries in the crossing of Norwegian fjords. Their design involves the adoption of accurate, but at the same time efficient models for the loads the structure is subjected to. Wave drift forces at the bridge’s pontoon may excite the bridge’s lower horizontal modes, with consequences to the loads on the bridge and mooring lines. Newman’s approximation is normally adopted to calculate the wave drift forces in such applications. A common simplification is to assume that the pontoons are fixed in the calculation of wave drift coefficients, while it is known that wave frequency motions may significantly influence drift loads. This paper evaluates the consequences of this simplification, in comparison to coefficients obtained considering the pontoons’ motions. First, the effect of the bridge deflection, due to mean drift, on the pontoon’s motions, is evaluated. It is found that this effect is negligible. Then, the RAOs are used in the calculation of wave drift coefficients, showing very different results than those obtained with fixed pontoons. Time-domain simulations are then performed with wave drift coefficients calculated with both approaches, with focus on the bridge girder moments and mooring line tensions. It is shown that using wave drift coefficients obtained with fixed pontoon is a non-conservative simplification, depending on sea state and wave incidence direction.
A Finite Element Model for Compressive Ice Loads Based on a Mohr-Coulomb Material and the Node Splitting Technique
Authors: Herrnring Hauke , Ehlers Sören 
Published: October 2021

Abstract
This paper presents a finite element model for the simulation of ice-structure interaction problems, which are dominated by crushing at low and medium confinement ratios. The failure mode of ice depends significantly on the strain rate. At very low impact velocities the ice behaves ductile, whereas at high velocities the ice reacts in brittle mode. This paper focuses on the brittle mode, which is the dominating mode for ship-ice interactions.
A multitude of numerical approaches for the simulation of ice can be found in the literature. Nevertheless, the literature approaches do not seem suitable for the simulation of continuous ice-structure interaction processes at low and medium confinement ratios in brittle mode. Therefore, this paper seeks to simulate the ice-structure interaction with the FE method. To preserve mass and energy as much as possible, the node splitting technique is applied, instead of the often used element erosion technique. The intention of the presented model is not to reproduce individual cracks with high accuracy, because this is not possible with a reasonable element size, due to the large number of crack fronts forming during the ice-structure interaction process. The objective of the here introduced Mohr-Coulomb Nodal Split (MCNS) model is to represent the essential material behavior of ice in a efficient formulation. To validate the findings of the model, the simulated maximum ice forces and contact pressures are compared with experiments.
Research on Influencing Factors of Heavy Oil Emulsification
Authors: Liu Yanchi , Wu Guodong , Yao Erdong , Zuo Wei , Zhao Longhao , Li Yuan , Meng Xue 
Published: October 2021

Abstract
In tight heavy oil reservoirs, the formation of W/O emulsion will significantly increase the viscosity of the whole fluid-system. Meanwhile, the emulsion droplets tend to block the core pores, which will reduce the flow oil and water. In this paper, the terms of oil-water ratio, pH and other factors on heavy oil emulsification of tight sandstone in a block of Xinjiang were studied. Furthermore, in order to study the emulsification behavior in large and small pores, a large tube and a small tube are used to investigate how the hole apertures affect heavy oil emulsification. Finally, the demulsification time and dehydration rate were recorded, and the interfacial tension and viscosity were tested. The results show that heavy oil is easy to self-emulsify with water to form W/O emulsion, and it’s extremely stable. When the oil-water ratio is 3:7, the viscosity of the emulsions reaches 307 mPa·s, which is 38 times higher than that of crude oil. Acidic and alkaline conditions are benefit of demulsification and the stability of the emulsions is reduced. In small tube with higher interfacial tension, the demulsification time is shortened, and the stability of the emulsions is reduced.
Interface Risk Reduction in an Integrated SURF-SPS Scope Execution
Authors: Priyadarshi Hemant , Nickel Daniel , Jose Seban 
Published: October 2021

Abstract
The paper provides a detailed estimation of the interfaces that exist in a split SURF-SPS execution model and provides a qualitative comparison to an integrated SURF-SPS execution model. A comprehensive matrix of dependencies between SURF and SPS is presented and is categorized into engineering, procurement, construction/fabrication and installation work packages. The matrix is used to illustrate the exact scope dependencies and thus, the sources of interfaces.
A hypothetical greenfield development has been assumed to develop the interface matrix and to use it for comparison of the two execution models. The comparison also reveals how interfaces are naturally eliminated in an integrated SURF-SPS execution model. In each of the workstreams (E-P-C-I), top risks have been identified and monetary liability estimates for those risks have been provided. By transfer of these risks from company to contractor, monetary liability gets transferred to the contractor, thus, resulting in significant savings for operating companies.
The following tangible results are provided in the paper: a) % of interface(s) reduced in the E-P-C-I areas; b) Risk reduction in monetary terms for operators – estimated values. This paper justifies the fact that there is a significant interface scope and risk reduction for operators, if they adopt an integrated SURF-SPS execution model.
Simplified Stochastic Modelling of the Force on a Pipe Bend Due to Two-Phase Slug Flow
Authors: Klinkenberg Arnout M. , Tijsseling Arris S. 
Published: October 2021

Abstract
Slug flow, a flow pattern with alternating aerated liquid pockets (slugs) and large gas bubbles, is a commonly observed flow pattern in oil and gas pipelines. Due to its unsteady character, the force on a pipe bend is fluctuating which results in unacceptable motions when the piping is insufficiently supported. To investigate the risk of fatigue failure of the system, finite-element models are used to predict the dynamic stresses required to estimate the fatigue life of the system. The excitation force of the slug flow is the essential input required for accurate fatigue damage predictions.
A new, simplified model of slug forces on a bend is proposed. The model is calculating the slug force by solving the momentum balance over the pipe bend using slug flow properties as liquid holdup and phase velocities. Average properties predicted by a unit slug model cannot predict the stochastic force variations caused by the slug flow. The new approach introduces the stochastic character of slug flow in the force calculations via a log-normal slug length distribution. A Lagrangian slug tracking method is used to solve the governing equations.
The modelled liquid holdup, pressure and predicted forces are compared with available measurements and Computational Fluid Dynamics calculations. The measurements were done under atmospheric conditions and the fluids used were air and water. Whether these measurements are representative for high-pressure oil and gas slug flow is unknown. By using a mechanistic approach where the main equations are based on physical laws instead of fitted measured data, the model is applicable for different fluids and operational conditions. To validate the model for oil and gas flows, the results are compared with Computational Fluid Dynamics calculations done with high gas density and typical oil viscosity.
Experimental, Numerical, and Statistical Investigation of Two Phase Flow in a Cylindrical Perforation Tunnel
Authors: Abobaker Ekhwaiter , Elsanoose Abadelhalim , Rahman Mohammad Azizur , Khan Faisal , Aborig Amer , Butt Stephen 
Published: October 2021

Abstract
Perforation is the final stage in well completion that helps to connect reservoir formations to wellbores during hydrocarbon production. The drilling perforation technique maximizes the reservoir productivity index by minimizing damage. This can be best accomplished by attaining a better understanding of fluid flows that occur in the near-wellbore region during oil and gas operations. The present work aims to enhance oil recovery by modelling a two-phase flow through the near-wellbore region, thereby expanding industry knowledge about well performance. An experimental procedure was conducted to investigate the behavior of two-phase flow through a cylindrical perforation tunnel. Statistical analysis was coupled with numerical simulation to expand the investigation of fluid flow in the near-wellbore region that cannot be obtained experimentally. The statistical analysis investigated the effect of several parameters, including the liquid and gas flow rate, liquid viscosity, permeability, and porosity, on the injection build-up pressure and the time needed to reach a steady-state flow condition. Design-Expert® Design of Experiments (DoE) software was used to determine the numerical simulation runs using the ANOVA analysis with a Box-Behnken Design (BBD) model and ANSYS-FLUENT was used to analyses the numerical simulation of the porous media tunnel by applying the volume of fluid method (VOF). The experimental data were validated to the numerical results, and the comparison of results was in good agreement. The numerical and statistical analysis demonstrated each investigated parameter’s effect. The permeability, flow rate, and viscosity of the liquid significantly affect the injection pressure build-up profile, and porosity and gas flow rate substantially affect the time required to attain steady-state conditions. In addition, two correlations obtained from the statistical analysis can be used to predict the injection build-up pressure and the required time to reach steady state for different scenarios. This work will contribute to the clarification and understanding of the behavior of multiphase flow in the near-wellbore region.
A Unique Approach in Modelling Flow in Tight Oil Unconventional Reservoirs With Viscous, Inertial and Diffusion Forces Contributions
Authors: Aldhuhoori Mohammed , Belhaj Hadi , Ghosh Bisweswar , Fernandes Ryan , Alkuwaiti Hamda , Qaddoura Rabab 
Published: October 2021

Abstract
A model for single-phase fluid flow in tight UCRs was previously produced by modifying the flow Forchheimer’s equation. The new modification addresses the fluid transport phenomena into three scales incorporating a diffusion term. In this study, a new liner model, numerically solved, has been developed and deployed for a gas huff and puff project. The new model has been numerically validated and verified using synthetic data and huff and puff case study. Ideally, the new model suits fluid flow in tight UCRs. The modified Forchheimer’s model presented is solved using the MATLAB numerical method for linear multiphase flow. For the huff & puff case, very simple profiles and flow dynamics of the main flow parameters have been established and a thorough parametric analysis and verifications were performed. It has been observed that the diffusion system becomes more prominent in regulating flow velocity with low permeability of the formation rock and low viscosity of the flowing fluid. The findings indicate a behavioral alignment with a previous hypothesis that matches actual reservoir behavior.
A Coupled Frequency and Time Domain Approach for Hydroelastic Analysis of Very Large Floating Structure
Authors: Chen Dengshuo , Feng Xingya , Hou Chao , Chen Jianfei 
Published: October 2021

Abstract
This paper develops a practical approach based on Python that couples the hydrodynamic analysis with the structural analysis, in order to solve the hydroelastic problem of Very Large Floating Structure (VLFS). The hydrodynamic analysis is carried out by solving linear 3D diffraction and radiation problems in the frequency domain, while the structural analysis is performed by a time-domain nonlinear finite element model. The coupling is realized by a generalized mode expansion method where the elastic deformation of the VLFS is regarded as extended radiation mode in the water. We consider a pontoon-type floating plate in regular waves. Analytical mode shape functions are used for representing the VLFS elastic deformations. The Mindlin plate theory is used for the finite element model. Convergence study of structure mode shape numbers, hydrodynamic model mesh and finite element model mesh is carefully carried out. Good agreements of the vertical displacement of the floating plate are found compared with experimental data and numerical results in the literature. Our simulation results show that the dynamic response of the VLFS is significantly influenced with consideration of its elastic deformation in the waves, and we see the influence is more pronounced in relatively shorter waves. The proposed approach is shown promising for hydroelastic analysis for more complex VLFS in realistic ocean seastates.