bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Computational Framework for Integrated Analysis and Hybrid Testing of Mooring Line Foundations
Authors: Abbiati Giuseppe , Zhang Zili , Franza Andrea , Andersen Lars Vabbersgaard , Stutz Hans Henning 
Published: October 2022

Abstract
Positional restraint of floating structures is achieved using mooring systems anchored to the seafloor. Design and risk assessment of these systems is challenging due to variability in wave, wind loading, ground conditions leading to uncertainty in the load-displacement behaviour of mooring line foundations for design. Accordingly, new simulation tools shall be able to support risk-informed integrated analysis of the floating structure as a system of interacting components subjected to realistic dynamic excitation. Also, all components of the floating structure simulation model shall be supported by experimental validation. In response to this need, this paper presents a computational framework for simulating the dynamic response of floating structures up to two second-order hydrodynamic loading. The framework utilizes the finite-element method and supports both integrated analysis and hybrid testing with focus on mooring line foundations. Computational efficiency is the driving criterion for tailoring the fidelity of the element library. Results of an ideal case study are used to test computational efficiency.
Analysis of Fluid Induced Transverse Forces on Multi-Strand Twisted Ropes
Authors: Schacht Stephan , Kosleck Sascha 
Published: October 2022

Abstract
Twisted multi-strand steel cables and ropes made of natural or synthetic fibres are the technical base for the manufacture of extended mechanically flexible structures. Examples can be found in a wide range of applications and subsystems throughout the maritime sector, e.g. experimental marine research, aquaculture, fishery and more. Here, one of the main concerns is the generated drag, a considerable quantity for flown through flexible structures. Furthermore, cables and ropes experience significant lift acting in the plain spanned by the cord vector, perpendicular to flow. In addition to that a transverse force occurs acting perpendicular to the plain spanned by the cord and inflow vector. This transversal force can generate significant deflections causing problems for example during towing processes. However, although of considerable impact this effect is often neglected with the underlying mechanisms not well understood.
This work presents an approach to derive these transverse forces examining the pressure distribution as well as the three-dimensional circulation around a multi-stranded rope. Following from that, two working theses are formulated:
1. The transverse force acting on multi-stranded ropes is a result of the circulation induced on the fluid by the geometry and its orientation to the incident flow.
2. The transverse force acting on multi-stranded ropes is comparable to the flow-induced hydrodynamic lift acting on an aerofoil.
With the use of experimentally determined pressure distributions across the surface of three-strand twisted rope segments at different angles of attack, cross-section-dependent circulation is demonstrated. The experimental data is compared with numerical calculations showing the limitations of a Reynolds-based approaches.
Study on Protective Structure Penetrated by the Shaped-Charge Jet for Ship Hull
Authors: Song Jingjing , Yue Jingxia , Li Xiaobin , Tan Runze 
Published: October 2022

Abstract
Based on the algorithm of Coupled Eulerian Lagrangian (CEL), the processes of the generation of shaped charge jet (SCJ) and the penetration to the inner and outer ship side plates were simulated by the finite element analysis (FEA). Meanwhile, the residual velocity of SCJ after penetrating the side plate could be obtained. In order to compare with the FEA results, the damage caused by the SCJ to the inner and outer plates of the ship side was experimentally studied, and the residual velocity was measured successfully. The comparison demonstrated that the values of the residual velocity obtained by simulation well agreed with the experimental results. The simulation indicated that the velocity of the SCJ decreased after penetrating the inner plate. Moreover, the influences of the ship side structural details, including the inner plate thickness, the distance between the inner and outer plates and the layout of the inner plate, on its protective ability against SCJ were investigated. The research indicated that increasing the thickness of inner plate and the spacing between inner and outer plates can effectively reduce SCJ residual velocity. Replacement of the inner plate with a multilayer plate could obviously reduce the SCJ residual velocity. The simulation method could describe the process of SCJ generation and penetration accurately, and the research results could provide references for the protective structural design of the ship hull attacked by SCJ.
Experimental Study on Asphaltene Deposition Characteristics in Yudong Block of Yingmaili Oilfield
Authors: Xu Hang , Zhou Fujian , Li Yuan , Zhu Liyan , Bai Hao , Yao Erdong 
Published: October 2022

Abstract
The oil wells in the Yudong block of Yingmaili area have encountered serious asphaltene deposition problems during production, which adversely affected the productivity of oil wells. Hence, it is necessary to carry out experiments to study the phase behavior of the well fluid and the characteristics of asphaltene deposition. Experimental research began with the preparation of simulated gas-bearing crude oil and the conduct of PVT tests. Then, the laser solid deposition analyzer was employed to study the asphaltene deposition characteristics of gas-bearing crude oil under reservoir conditions. Finally, differential scanning calorimetry experiment was carried out to measure the initial asphaltene precipitation temperature and quantitative characterization the deposition amount of the ground degassed crude oil. Results show that there are four phases areas of “gas-liquid-solid”, “gas-liquid”, “liquid-solid” and “pure liquid” for gas-bearing crude oil at different temperatures and pressures, and temperature is an important factor affecting asphaltene precipitation in Yudong oil wells. The initial asphaltene precipitation temperature of the surface degassed crude is 23.05 °C, with instantaneous deposition reaching a maximum of 0.01178 % at 6.2 °C and cumulative deposition reaching 8.34 % at −30 °C. This research provides a strong support for effectively overcoming the asphaltene blockage challenge in Yudong block.
FPSO Second-Order Roll Motions and the Impacts on SLWR Riser Design
Authors: Prado Vinicius G. , Senra Stael F. , Ferreira Marcos Donato A. S. , Oliveira Allan C. , Sena Bernardo D. 
Published: October 2022

Abstract
The dynamic behavior of risers is highly influenced by the FPU motions, due to the effects of the environmental conditions (waves, wind and current) on the hull. Representing the wave numerically by a velocity potential, we will assume that it can be expanded as a power series with respect to a parameter ε. The first order effects generate motions with the same frequency of the incident waves and are directly proportional to their amplitude. Second order effects generate motions with frequency equal to the difference (low frequency) or sum (high frequency) of the frequencies of the incident waves, treated as bichromatic in the numerical model, and are proportional to the product of the amplitude of each incident wave in this pair.
Significant second order motions are commonly observed in the horizontal plane (surge, sway and yaw), due to the low mooring stiffness. Recently, however, this phenomenon was also observed for roll motions in several new FPSOs that will operate in the Pre-Salt of Santos Basin. The phenomenon had already been detected in a deep draft semi-submersible from Campos Basin, but only more recently in FPSOs.
The new units have high roll natural periods, above the typical wave period range on the pre-salt region, but the roll response occurs with periods close to the natural period of the system and can be significant. In this way, sea states with incident waves in the Santos Basin typical period range (4 to 20 s) generate additional roll excitations and motions on the floater outside the incident range (above 20 s). This phenomenon was detected in model tests and confirmed by numerical studies.
This new FPSO behavior requires some care with how the risers and their interfaces will be studied. While 2nd order motions of surge, sway and yaw can impose a slow motion on the riser system due to their periods being typically well above 150 s, 2nd order roll motions are only slightly above 20 s, imposing displacements and accelerations that can directly affect the behavior of the riser top region.
This paper aims to present the joint effort of Petrobras’ Naval Architecture and Subsea Risers teams to properly represent this phenomenon in FEM time-domain riser analyses, as well as the most important issues observed and incorporated into the risers’ projects in terms of extreme combined load effects and wave&motion fatigue.
Simulation of Trawl Board and Pipeline Pull-Over Interaction
Authors: Longva Vegard , Levold Erik , Ilstad Håvar , Sævik Svein , Klæbo Frank , Finstad Opgård Marie , Arenfeldt Vilsen Stefan 
Published: October 2022

Abstract
This paper presents a finite element (FE) model for simulation of trawl board and pipeline pullover interaction. The considered trawl gear system is referred to as a single otter trawl. This system consists of a single trawl net, two trawl boards and a fishing vessel which are connected by steel ropes. The trawl net was modelled by a new simplified trawl net model ensuring high computational efficiency. This trawl net model can simulate the correct tension level in the steel ropes connecting the trawl net and the trawl boards during the pipeline interaction phase, which is crucial to obtain a realistic trawl board interaction behaviour. The trawl boards were modelled as 6-DOF rigid bodies which were assigned a tailormade hydrodynamic load model based on a 3-parameter interpolation scheme both for the added mass and the forward-speed induced loads. Compared to previous work, the applied interpolation scheme was extended and improved in terms of parameter choice and number of parameters. The forward-speed induced loads consist of drag and lift loads. These loads were estimated by flume tank testing considering numerous trawl board configurations in terms of angle of attack, board-seabed inclination angle and gap between the trawl board and the seabed. Detailed measurements of the trawl board applied in the flume tank test were done to obtain an accurate description of the contact geometry, the centre of gravity and the rotational mass properties. The proposed FE model was validated against model test results of trawl board pull-over considering variation of pipeline height, pipeline diameter and trawling velocity. The FE model was found to give very good agreement with the model test in terms of build-up of pipeline interaction forces, peak force level and duration. The FE model is therefore regarded as applicable for use in design analysis of pipeline and trawl board pull-over interaction.
Oscillation of a Flexible Catenary Shaped Submersed Pipe Induced by Two-Phase Slug Flow of Liquid and Gas
Authors: Silva Jéssica P. , Morooka Celso K. , Bordalo Sergio N. , Trigo Caio C. O. 
Published: October 2022

Abstract
In this paper, an experimental study of the excitation of a submersed suspended flexible pipe induced by the internal two-phase slug flow of liquid and gas is presented. The experiment was conducted with the pipe set in catenary configuration inside a water tank with a depth of 2m. Water and air were injected into the pipe at various flow rates combinations, leading to the formation of horizontal slug flow patterns. The slug two-phase flow generated intermittent loads on the pipe causing its oscillation. The dynamic response of the pipe to the slug flow was monitored by cameras which registered the movement of target marks set up along the body of the pipe. Processing the video images, we obtained the time-history of the movement of the pipe, and from this, the frequencies and amplitudes of motion were determined. With the proper scaling up, and in conjunction with computer simulators of pipe dynamics running intermittent load models of slug flows, the present work may be helpful to improve the capability of engineers for the analysis of the behavior of suspended risers used in offshore petroleum production carrying up oil and gas from petroleum reservoir wells to floating production facilities.
Energy Efficiency and Mitigation of Greenhouse Gases in FPSOs Ships
Authors: Castro Gustavo , de Barros Gallo Alexandre , Fossa Alberto José , Moutinho dos Santos Edmilson 
Published: October 2022

Abstract
Among the main opportunities reviewed and highlighted within the industry’s value chain, the upstream sector stands out and includes exploration and production activities for oil and natural gas, subdividing into key areas that concentrate a high demand for energy and, consequently, a relevant portion of emissions. A review and discussion about the FPSOs ships can be justified by market factors since ships currently comprise the main global offshore oil production systems. Among the highlights in the scope of emissions, the activity indexes are mainly composed of carbon dioxide (CO2) and methane (CH4), in addition to containing minimum levels of nitrous oxide (N2O). Whereas for emissions — which can occur either by combustion or by leakage or treatment processes — are divided and presented into four groups: Power generation (68% CO2 and 7% CH4), flaring (26% CO2 and 18% CH4), unintentional fugitives sources (0.02% CO2 and 22% CH4) and chemical ventilation (6% CO2 and 53% CH4). Although it still presents difficulties in operational implementation, the promotion of research and policies on the emission of greenhouse gases in the oil industry can help and enable the construction of a more secure, sustainable, and integrated energy future.
Human-Machine Engineering Virtual Simulation for the Wheelhouse on Large Ships
Authors: Li Chuntong , Wei Naikun , Luo Xiaomeng , Lv Jianjun , Yang Xuelian , Wang Deyu 
Published: October 2022

Abstract
The research of the wheelhouse ergonomic design for large ships is of great significance to minimizing wheelhouse human errors and guaranteeing the safety of ship navigation. To obtain a better human-machine engineering implementation effect and a faster feedback during the wheelhouse designing, the paper proposed a virtual simulation and evaluation method. First, based on anthropometry and relevant theoretical knowledge of human dynamics, the virtual crew database was built via 3dsMax, and task actions such as crew walking, operating buttons, and observation were defined. Second, the design requirements of ship wheelhouse human-machine engineering were summarized from an overall perspective. Subsequently, a virtual simulation of the working environment was implemented, while the layout and design of the wheelhouse structure were analyzed. Besides, the evaluation index system was constructed in an analytic hierarchy process. Finally, a digital integrated evaluation system was established to evaluate the man-machine interface design for the wheelhouse, including three-dimensional digitalization model, real-time virtual simulation and human-computer interaction design, which verifies the effectiveness of the proposed evaluation method. According to the corresponding profound evaluation result analysis, the suggestions for improvement were put forward.
Spatial Distribution of Impact Pressure Impulse on a Semi-Submersible in Irregular Waves
Authors: Zhang Nianfan , Xiao Longfei , Wei Handi , Teng Xiaoqing , Guo Yinghao 
Published: October 2022

Abstract
Semi-submersible platforms have been widely used in offshore oil and gas exploitation due to their excellent performance, but wave impacts in extreme sea states remain a major concern. For the design of offshore structures with sufficient structural capacity, scholars have pointed out the wave pressure impulse obtained by time integration is more crucial compared with the peak impact pressure. In this study, wave basin experiments were carried out under a series of irregular waves to study the spatial variations of pressure impulse on a semi-submersible. To capture more wave impact events and get more accurate local impact pressures, a large number of impact load measurement units were compactly installed on two adjacent surfaces at the corner of test model. The probability statistical method is adopted to analyze the nonlinear features and spatial variations. The results show that the pressure impulse on a semi-submersible in irregular waves has strong variability and its spatial distribution presents local concentration features. It is found that wave impacts on the column are more serious and the variations of pressure impulse on the column are greater than that on the side of deck box under head sea state. Spatial variations of pressure impulse on a semi-submersible are severely affected by significant wave height Hs and spectral peak period Tp of irregular waves. Meanwhile, the number of wave seeds used in model tests have a decisive influence on the estimation and spatial variation of wave pressure impulses. The perspectives given in this study may provide references for the structure design of semi-submersible platforms and lay a foundation for improving the laboratory experiment of wave impacts.
Casing Collapse Resistance Under Long-Term, Non-Uniform Salt Loading
Authors: Batruny Peter , Campbell Scott , Rahim Azral , Yun Thiam Yap , Yunus Syed , Lumley Pete , Suryanarayana Poodipeddi V 
Published: October 2022

Abstract
Collapse loads from uneven salt loading have been and remain a topic of discussion in the oil and gas industry. Studying this phenomenon requires large amounts of resources and risk for operators and casing vendors alike. As Oil and Gas exploration and development moves into deeper waters and more challenging conditions, novel ways of design need to be adopted to keep costs low and maintain well integrity throughout the well life cycle. Different methods and concepts from vendors, operators, and engineering consultants in casing design for long term salt loading have been reviewed and analyzed. A common Casing design software was used to analyze the different methods through modelling and load analysis with the subsequent results compared. A reliability-based design approach incorporating deforming casing dimensions and failure probabilities is proposed. A decision-making flow chart is also developed to avoid over-designing and safely optimize casing design for an exploration keeper-well. Reducing uncertainty of uneven salt loading on production casing will pave the way for more fit-for-purpose well designs. By doing that, less material surplus is generated resulting in less waste and less emissions.
Short-Term Extreme Response Prediction for a Jacket Platform Subjected to Nonlinear Wave Loads
Authors: Chai Wei , Yu Xiangpeng , Leira Bernt J. , Gu Jian 
Published: October 2022

Abstract
For bottom supported jacket platforms, the wave loads are generally nonlinear due to the drag-term in the Morison equation. As a result, the associated dynamical response for the offshore platform, such as the overturning moment and the base shear force, exhibit pronounced nonlinear characteristics. In this work, the dynamic response of the jacket platform is described by a single-degree-of-freedom (SDOF) model. The nonlinear wave load in the SDOF model is modeled as a polynomial of a filtered white noise. Subsequently, by application of the linear filter technique, the SDOF model is extended into a four-dimensional (4D) Markov dynamical system, whose probabilistic properties are governed by the corresponding Fokker-Planck equation. The path integration (PI) method is applied in order to solve the Fokker-Planck equation by taking advantage of the Markov property of the dynamical system. The response statistics calculated by the PI method are validated by Monte Carlo simulation (MCS). The statistical characteristics of the response for the jacket platform subjected to nonlinear wave loads are determined by means of numerical simulations. For the selected sea state, the mean upcrossing rates of the dynamical responses, i.e. the overturning moment and the base shear force, are employed to obtain the extreme responses of the jacket platform.
The Dynamic-Static Coupled Full Field Optimization of ICD/AICD Completion for the Pilot Wells Selection and Design in N Oilfield Middle East
Authors: Wu Bohong , Shi Shuzhe , Liu Jing , Wei Chenji , Li Yong , Li Baozhu , Lou Yuankeli , Yu Tao 
Published: October 2022

Abstract
Horizontal wells with open-hole completions are very common in N field Middle East, over 80% of the well completions are open-hole completions. However, in recent years’ production, some of the open-hole wells face several challenges from the perspective of reservoir management, such as early-stage water/gas breakthrough and inefficient drainage around the wellbore. These challenges are caused by the existence of high permeability streaks and the heel-to-toe effect. Therefore, aiming at these challenges, the present work proposed the lower completion strategy and established the lower completion workflow to implement inflow control devices (ICD) or autonomous inflow control devices (AICD) with packers, and selected some representative wells in N oilfield to find out the lower completion optimization results of the whole well life.
The principles of screening and selecting the pilot candidate wells in the N field middle east are operable, duplicable, and valuable. The pilot wells need to be the representatives in both geology and engineering, scheduled to be drilled recently and able to be evaluated from numerical simulation. For the comprehensive production analysis, the static model was used for sensitivity study and optimization and the dynamic model was used for the full-field assessment. The sensitivity and uncertainty of design parameters include compartment length, nozzle size, cross-section area and flow coefficient. Then, the static model was coupled with the dynamic model to obtain the optimal lower completion settings of the whole well life. The dynamic sector model that included injection wells and production wells was derived from a full field model. By using the optimized ICD/AICD parameters and deploying the tools correctly based on reservoir heterogeneity, the reservoir performance such as water cut, gas-oil ratio and cumulative oil production can be obtained to validate the optimization results. Several cases were studied to demonstrate the production improvement and economic values with the optimized lower completion. It is shown that the cumulative oil production will increase, the production plateau will extend and the overall NPV will be higher.
This work can give guidance to the selection of the most fit-for-purpose lower completion technology for different well objectives when facing different kinds of challenges.