bluuebunny/crossref_metadata_2025_split huggingface dataset:
Well Integrity: Preliminary Risk Analysis for Different Well Life Cycle Phases
Authors: Abreu Danilo T. M. P. , Morais Carlos H. B. , Santos Joaquim , Colombo Danilo , Martins Marcelo R. 
Published: November 2019

Abstract
The life cycle of an oil well contains several phases, such as design, construction (drilling, completion and evaluation), production, intervention and abandonment. Moreover, each phase includes its particular operational modes (e.g., in the intervention phase there are wireline and coiled tubing operations). One of the main concerns during each phase refers to the risk of uncontrolled hydrocarbon flow to the environment, which is mitigated by measures that ensure well integrity through the use of well barriers. In this sense, the concept of two independent well barriers, reinforced by standards such as NORSOK D-010, leads the efforts in the industry, but does not clearly addresses the risks.
A failure in the well barrier elements leads to undesired events involving oil flow to the environment, damages to equipment and personnel loses. However a full comprehension of how these events contribute to the risk should take into account factors regarding the operational conditions. For instance, when the wellbore is exposed, an influx of hydrocarbons tends to release a biggest amount of oil to the environment than when the completion is installed. Additionally, older wells tend to sustain a smaller pressure when compared to other wells in the beginning of their life cycles — what also impacts on the consequences of undesired hydrocarbon flows. Nonetheless, these accidents should be pondered by their probability of occurrence for a full addressment of the risk.
In order to contribute to a risk-oriented view of issues related to well integrity, this work presents a customized Preliminary Risk Analysis framework. The simultaneous combination of well barrier elements failures constitutes the base of the analysis, which is complemented by control and monitoring measures. Hazards are also described according to their operational conditions, allowing treating this aspect separately.
An Experimental Development to Characterise the Flow Phenomena at the Near-Wellbore Region
Authors: Ahammad M. Jalal , Rahman Mohammad Azizur , Butt Stephen D. , Alam Jahrul M. 
Published: November 2019

Abstract
The understanding of rock characteristic and fluid flow behavior at the near-wellbore region is an important topic. Triaxial experiment setup can help to investigate these properties. In this research, a new triaxial experimental setup has been developed where the higher scale of the parameters such as higher reservoir pressure, and comparatively larger core sample can be used. High permeable synthetic porous samples are prepared to validate the device. The new triaxial experimental setup is validated with water as a base fluid. In the validation test, real samples and synthetic samples are used. First, flow in convergent direction is studied which represents as production at the in-situ condition. Then, the flow in divergent direction is examined that may represent the injection of fluid to enhance the hydrocarbon production. The near-wellbore flow phenomena are studied with real and synthetic samples. The results indicate that using this triaxial setup pressure drop and pressure buildup test can be explained. The new scientific setup is able to reduce the scale-up gap between laboratory data and field data to get actual reservoir flow phenomena.
Numerical Investigation for Vortex-Induced Vibrations of Steel-Lazy-Wave-Risers: Part II — CFD Study on Long Flexible Riser
Authors: Jang Hyunchul , Kim Jang Whan 
Published: November 2019

Abstract
Vortex-Induced Vibration (VIV) is one of the main sources of fatigue damage for long slender risers. Typical VIV assessment of risers is conducted using semi-empirical software tools in which the sectional hydrodynamic coefficients are derived from forced oscillation model tests on short rigid risers. The Steel Lazy Wave Riser (SLWR) with buoyancy sections is an attractive concept for improving fatigue performance in deep water developments, but there is limited model test data available for the hydrodynamic coefficients on SLWR’s. In Part I of the present study (Jang & Kim, 2019), CFD simulations are successfully validated against forced-oscillation model tests. In this paper, the feasibility of using CFD simulations for VIV response of a long flexible SLWR has been studied based on the CFD modeling practice developed in Part I. The CFD simulation is coupled with a simple structural model of the riser, and the structural equations of motions are solved via modal analysis. The simulation results capture all excitation frequencies measured from the model tests.
Analysis on the Influence of an Energy Storage System and its Impact to the Grid for a Wave Energy Converter
Authors: Stefek Jeremy , Bain Dominique , Yu Yi-Hsiang , Jenne Dale , Stark Greg 
Published: November 2019

Abstract
Reducing power fluctuations is essential for controlling the integration impacts of wave energy converter (WEC) plants in both distribution and transmission grids, and in stand-alone isolated power systems. This paper presents an analysis on the cost of and how a battery storage system can be used to further reduce the variation of power generated from the WEC due to the fluctuating nature of waves and its impact to the grid. The electrical power output from WEC-Sim simulations for the six sea states used in the Wave Energy Prize was analyzed to compute the peak power and power time history. The results were used to evaluate the battery storage capacity that is needed for a WEC system to provide reasonable power flow to the grid and estimate its cost based on the latest cost information for battery technologies published by the U.S. Energy Information Administration. Finally, a preliminary grid integration analysis was performed to demonstrate how WEC-generated power would contribute to a small island electricity system. As shown in the study, the instantaneous peak power is the primary cost driver for the battery storage and the power take-off system, and reducing the power fluctuations is essential for reducing the overall levelized cost of energy (LCOE). The power flow variation from WECs can be significantly reduced using battery storage without adding significant overall system costs, and the implementation of battery storage is essential for grid integration applications. There may also be additional opportunities to further investigate energy storage technologies that are specific to WEC applications to reduce these costs even further.
Numerical Investigation of Wave-Frequency Pontoon Responses of a Floating Bridge Based on Model Test Results
Authors: Shao Yanlin , Xiang Xu , Liu Jianyu 
Published: November 2019

Abstract
The wave-induced responses in the bridge girder of long floating bridges supported by pontoons are often dominated by the vertical modes, coupled horizontal modes and rotational modes about the longitudinal axis of the bridge girder. Pontoons with and without bottom flanges have been seen in recent floating bridge designs. Viscous flow separation around the sharp edges of the pontoon or the bottom flange may have strong influences on the hydrodynamic performance of the pontoon in terms of wave excitation, added mass and damping effects. Morison-type wave and current loads are normally included empirically in the early design phases to account for the viscous effects that cannot be covered by a potential-flow solution alone. Empirical drag coefficients and perhaps a correction to the potential-flow added mass are the inputs to such numerical models, which represents a part of the modelling uncertainties. Previous sensitivity studies using different drag coefficients in the ongoing Bjørnafjord floating bridge project in Norway indicate an influence up to 15% on the maximum vertical bending moment around the weak axis of the bridge girder.
This paper contributes to the understanding of viscous effects on the hydrodynamic characteristics, e.g. the added mass, damping and wave excitation loads, of a floating bridge pontoon with and without keel plate. This is achieved by exploring existing model tests for floating bridge pontoons, performing 2D Computational Fluid Dynamic (CFD) analysis for pontoon cross sections and numerical calibration in a simplified frequency-domain model with linearized drag loads. Scale effects are also investigated through CFD analyses in model and full scales.
Impacts of Condensate Storage on the Hull Structure Design of Semi Submersible Platform
Authors: Feng Jiaguo , Yu Yi , Li Da , Xie Bin , Xie Wenhui , Zhu Haishan , Wu Min 
Published: November 2019

Abstract
In order to develop the gas field in South China Sea, a deep-draft semi-submersible platform with 20000 m3 condensate storage tanks was selected. There is little industrial experience for semi-submersible platform with the condensate producing and storage tanks. This paper presents the impacts caused by the condensate producing and storage on the hull structure design in FEED phase. The design life is 30 years without returning to drydock for repair or maintenance.
The main unique features are illustrated as follows. Firstly, the double-wall voids (cofferdams) of 1.8 meters width were designen to prevent condensate leakage in the column around the condensate tanks. The double-wall bulkheads were connected by flats with manholes for maintenance access. this is different from conventional semi-submersible platform. Secondly, the non-watertight bulkheads in the middle of the condensate tank were needed to meet the efficient strength requirements for structural design. The upper and lower 2m height gaps on the bulkhead are convenient for the flowing of bottom condensate and top gas in condensate tank respectively. It is proven that the optimized design of continuous non-watertight bulkhead for the condensate tank is feasible, safe and reliable based on the global strength and fatigue analysis. Thirdly, The additional corrosion margin of 2mm was added to the boundary of frequently ballast and de-ballast tanks in the nodes and columns, and to the bottom plate and the side shell of 2m height from the bottom of condensate tanks considering the SEMI design life of 30 years. Fourth, the pressure head for condensate tank scantling design was increased by 10 m per condensate tank vent head location on topside. Fifth, there are some indirect effects due to the condensate storage, such as the increase of displacement and the load on the SEMI. Therefore, the hull structure needs to be reinforced, especially on the key connections, such as the column and pontoon connection, the deck and hull connection. It is recommended to pay attention to these critical locations with detailed local analyses.
Residual Stress in Girth Welds: Seeing Measurement Data Differently
Authors: Mirzaee-Sisan Ali , Wu Guiyi 
Published: November 2019

Abstract
This paper studies some of the recent residual stress measurement data on pipeline girth welds, which are available in the open literature, using a statistical approach. The measurement data points from residual stresses profiles are separated into three different zones, ie, outer zone, inner zone and middle zone, to study their distributions statistically. This statistical analysis indicates that for the region close to the outer surface, where welding is most likely to produce critical flaws, most of the reported measurement data points lie below the yield strength of the base metal. The paper concludes by presenting a case study using deterministic and probabilistic fracture analyses and providing some recommendations for further improvement of the relevant codes and standards.
Impact of the Uncertainties of the RAOs of a Semisubmersible Platform on the Performance of a Motion-Based Wave Inference Method
Authors: Mas-Soler J. , de Mello Pedro C. , Tannuri Eduardo A. , Simos Alexandre N. , Souto-Iglesias A. 
Published: November 2019

Abstract
Motion based wave inference allows the estimation of the directional sea spectrum from the measured motions of a vessel. Solving the resulting inverse problem is challenging as it is often ill-posed; as a matter of fact, statistical errors of the estimated platform response functions (RAOs) may lead to misleading estimations of the sea states as many noise values are severely amplified in the mathematical process. Hence, in order to obtain reliable estimations of the sea conditions some hypothesis must be included by means of regularization parameters. This work discusses how these errors affect the regularization parameters and the accuracy of the sea state estimations. For this purpose, a statistical quantification of the errors associated to the estimated transfer functions has been included in an expanded Bayesian inference approach. Then, the resulting statistical inference model has been verified by means of a comparison between the outputs of this approach and those obtained without considering the statistical errors in the Bayesian inference. The assessment of the impact on the accuracy of the estimations is based on the results of a dedicated model-scale experimental campaign, which includes more than 150 different test conditions.
Research on Characteristics of Removing Particles in Ship Exhaust Gas by Charged Droplet
Authors: Jiao Lei , Qian Zhaohui , Huang Dekai , Zhou Peilin , Chen Pengfei , Meng Lida 
Published: November 2019

Abstract
A traditional water scrubber is able to remove particles with a size over 200 μm in ship engine exhaust effectively. However, as the size of the particles decreases, the removal efficiency of the particles is gradually reduced, especially when the particle size is less than 50 μm, the method almost has little effect. This paper presents a study of charging particles in exhaust gas and water droplets to improve water scrubber’s efficiency in removing fine particles. The charging of the particles is mainly achieved through corona discharge, while the water droplets are charged by passing the high-voltage electricity to the nozzle. However, the feasibility and economics of these two methods have not been verified in other researches, so they are numerically simulated by Comsol Multiphysics software in this paper. The simulation results show that both particles and droplets can be charged steadily by the two methods. The numerical simulation results also indicate that the removal efficiency of particles in ship exhaust gas can be greatly improved by adding charges to droplets and particles at the same time. And a line chart of particle capture efficiency map under different particle sizes and change of droplets is obtained.
Interaction of Fixed Cylinder With Waves Through Weakly Coupled FNPT and Lagrangian Navier-Stokes
Authors: Agarwal Shagun , Sriram Venkatachalam , Murali K. 
Published: November 2019

Abstract
This paper presents a 2D/3D hybrid numerical model for studying the interaction of non-breaking waves with cylindrical structure. The work combines the strengths of mesh-based and particle-based methods, where the wave propagation is solved using 2D mesh-based potential theory model and the interaction with the structure is solved using 3D particle-based Navier-Stokes model. The paper presents the formulation of the two models and the weak-coupling methodology, along with recent improvements in the 3D MLPG_R (Mesh-less Petrov-Galerkin based on Rankine source solution) particle based method. The numerical results from interaction of fixed cylinder with solitary and focussed waves are compared with experimental data. The work demonstrates a significant reduction in simulation time for wave-structure interaction problems achieved using this hybrid approach without compromising on accuracy.
Effect of Flexible Joint Modelling Method on Deep Water Catenary Riser Hang-Off Fatigue Response
Authors: Hu Guanyu , Huang Chaojun , Yin Fengjie , Cerkovnik Mark , Yang Guangqiang 
Published: November 2019

Abstract
The Flexible joint is one of the most widely used hang-off systems for deep water catenary riser for its large rotation and load bearing capacity. The fatigue performance of riser hang-off region and fatigue load on the flexible joint highly depend on the rotational stiffness of the flexible joint. Thus, modelling the flexible joint stiffness to accurately simulate the behavior under cyclic bending cycles is critical in global riser fatigue analysis.
The load-displacement relationship of a flexible joint typically follows a nonlinear curve, and it shows hysteresis behavior when subject to cyclic bending cycles. However, in current industry practice, the flexible joint stiffness is modelled either as a nonlinear curve or simplified as a fixed value. These simplified methods sometimes can lead to unconservative or over conservative results in riser design. Modelling the flexible joint stiffness in an accurate approach becomes more important especially when the riser fatigue is critical at the hang-off region. In addition, the design of flexible joint will also be impacted by the fatigue load extracted from global fatigue analysis, which is also largely affected by the flexible joint stiffness modelling method. Thus, modelling a flexible joint by accounting for the nonlinear hysteretic stiffness is recommended. This paper compares the different modelling methodologies of the flexible joint for catenary riser hang-off and presents the impact on fatigue performance considering hysteretic behavior. This study considers the effects of wave amplitude and hosting vessel offset.
A case study is also presented on the application of all the modelling methods on fatigue performance of an SCR in the Gulf of Mexico. The fatigue behavior is compared for the different modelling methods considering long term wave motion and platform offsets. The impact on the results from different types of hosting platform is also discussed.
Safety and Risk Management Analysis of Accidents Related to Pressure Vessels and Piping in Alberta Petrochemical Industry From 2008 to 2017
Authors: Esouilem Mohamed , Bouzid Abdel-Hakim , Nadeau Sylvie 
Published: November 2019

Abstract
In recent decades, many accidents involving pressure vessels and piping components (PVP) have occurred in North-America. Several studies have been conducted to understand their causes and find suitable solutions to reduce their frequency. Most of the researches have focused on the technical causes of these accidents and the subsequent implementation of safety management strategies. These researches highlight that the main technical causes are leak and rupture. From this standpoint, it is important to deepen the study of leaks and ruptures accidents. In Alberta alone, the Alberta Energy Regulator (AER) demonstrated that more than 15 root causes initiated leak and rupture failures in PVP since 1990.
This paper presents an analysis of the frequency of accidents, their severity, their causes and the risk associated in the Alberta petrochemical industry from 2008 to 2017. This study proposes an exponential decay to estimate the frequency of accidents involving PVP and identifies the most important causes based on a severity analysis. The results based on the developed model show that there is a good agreement between the predicted and observed accidents frequency from 2008 to 2017. The severity analysis results show that the main factors contributing to accidents are corrosion, construction deficiency and overpressure. Finally, the proposed model of frequency and severity of observed and predicted PVP failures needs improvements to better predict the risks and be useful for prevention.
On the Microstructural Evolution and Porosity Consolidation in 316L Stainless Steel During Hot Isostatic Pressing
Authors: Cooper Adam J. , Tuck Olivia C. G. , Armson Samuel A. J. , Preuss Michael 
Published: November 2019

Abstract
If advanced manufacturing technologies are to be adopted over conventional manufacturing processes in the nuclear industry — the most regulatory challenging industry — rigorous fundamental studies that develop underpinning knowledge, materials performance data, and predictive capabilities are essential. Herein we have employed the use of electron backscatter diffraction (EBSD) and 3D X-ray computed tomography (XCT) to characterize microstructure evolution and porosity consolidation during the early stages of powder metallurgy hot isostatic pressing (PM-HIP). The data herein highlight the mechanisms through which the powder particle size distribution encourages localized plastic deformation and subsequent microstructural recrystallization of Type 316L stainless steel; the effect of powder particle size distribution on the rate of porosity consolidation is also discussed. Specifically, we have determined the temperature and pressure conditions that are required to initiate dynamic recrystallization during HIP, and explain how this is influenced by the powder particle size distribution.
Japanese Welding Guideline for Duplex Stainless Steels
Authors: Iwamoto Hiroyuki , Minami Fumiyoshi 
Published: November 2019

Abstract
A Japanese welding guideline for duplex stainless steels (DSSs)1) has been developed in a Sub-Committee of Chemical Plant Welding Research Committee in the Japan Welding Engineering Society. The guideline recommends 13 key points as a basis to prevent the unforeseen corrosion of weldments, which are based on practical experience in Japanese Oil & Gas and Chemical industries and similar published guidelines. The principal concept is how to obtain an acceptable ratio of ferrite/austenite phase balance along with no detrimental intermetallic compounds in the weld metal and heat affected zone. For the weld metal, consumable selection, the shielding and purging gas composition and weld heat input control are most critical. For HAZ, the nitrogen content of the base metal is most critical. This guideline is developed for DSS welders and welding engineers so as to understand the difference of DSS from standard austenitic stainless steel. This guideline is composed of three parts, the first is 13 basic recommendations, the second is to explain some technical aspects for these 13 key points and the third contains comprehensive data relating DSS base metal and weld metal including some important key points for each step of fabrication to understand the welding characteristics of DSS clearly.
This paper introduces the basic 13 recommendations for guidance purpose in addition to the mandatory requirements of the construction code in Japan.