bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Artificial Intelligence for VIV Strake Optimization of Steel Lazy Wave Risers
Authors: Lal Mayank , Sebastian Abhilash , Rana Yashpal 
Published: October 2022

Abstract
Vortex Induced Vibrations (VIV) may cause significant fatigue damage in Steel Lazy Wave Risers. The severity of the VIV fatigue damage is dependent on the natural frequency of the riser and the vortex shedding frequency which varies according to long-term current profiles and distribution. VIV suppression devices such as strakes, fairings and integrally straked buoyancy modules are used on riser pipe to reduce the fatigue damage caused by vortex induced vibrations. However, the higher the coverage of these suppression devices, the higher the Engineering, Procurement, Construction and Installation (EPCI) cost of the riser.
Strakes are the most commonly used suppression devices for deep water risers. The buoyancy section of the Steel Lazy Wave Riser needs to be straked if it becomes a driving power in region for vortex induced vibrations. As VIV strake coverage increases, the installation time for the riser increases which can significantly affect the EPCI cost of a riser due to the high day rate of installation vessel. Hence optimizing the coverage of strakes can result in significant savings. Typical strake coverages on risers can range from 30–90% of riser suspended length for Gulf of Mexico projects while in South America it can range up to 100% including the buoyancy region.
Genetic algorithm is applied within an artificial intelligence tool to optimize the coverage and location of strakes along the riser automatically using an objective function with the aim of minimizing the strake coverage length. The algorithm for the proposed artificial intelligence tool along with the objective function are presented in the paper followed by a few examples showing the efficacy of the tool. While optimizing the coverage and location of strakes on risers is an iterative and cumbersome process, the use of the artificial intelligence tool presented in this paper will help an engineer speed up the strake coverage design and improve the quality of VIV analysis performed together with savings on EPCI cost of steel lazy wave risers.
Influence on Sealing Integrity by Pressurization During Cement Sheath Setting
Authors: Wu Xuning , Li Zaoyuan , Liu Jian , Hou Zhengmeng , Su Donghua , Li Jin 
Published: October 2022

Abstract
After cement slurry is injected into the a well, weight loss will occur before the cement sheath is formed, so that the pressure of the cement slurry column will gradually decrease, which will increase the risk of micro annulars at the casing-cement sheath-formation interface. In this study, one cement sheath sealing integrity test platform integrated with curing and testing was established to simulate the hydration weight loss process in the cement sheath setting. The sealing integrity of the cement sheath under stage pressurization and rapid depressurization was tested. Using the theory of thick-walled cylinder of an elastoplastic mechanics, the development of the elastoplastic interface of the cement sheath under the change of casing internal pressure was calculated, and the calculation method of equivalent crack width were established. The research results show that, the greater the setting pressure loaded during the curing process on the cement sheath, the higher the stress that the cement sheath can withstand during the later operation. After the cement sheath body is destroyed, as the internal pressure of the casing decreases, the width of the micro cracks increases. The research results of this paper can provide an important reference for designing mechanical properties of cement sheaths and improving the sealing ability of cement sheaths.
The Influence of Directional Well Azimuth on Bit Performance: A Statistical Approach
Authors: Nour Muhammad , Farahat Mohamed S. , Mahmoud Omar 
Published: October 2022

Abstract
The drilling cost represents a significant portion of total well cost, especially for directional wells. The major component of drilling cost is determined by how fast a well is drilled, i.e., rate of penetration (ROP). Many factors affect ROP including bit type and condition, formation characteristics, and drilling parameters. One factor that is usually ignored is the direction of drilling (well azimuth). Literature introduces many thoughts about effect of well azimuth on important issues like wellbore stability, but unfortunately it lacks high quality researches about azimuth/performance relationship. The objective of this paper is to test the influence of drilling azimuth on drilling performance.
This relationship was studied in terms of ROP, and drillability exponent (DEXP), which can be used for drilling performance assessment besides well control applications. Drilling data from different areas was processed and categorized by fields and formations. In-Depth statistical analysis was performed, and visualization tools like heat maps were generated to assess the relationship between drilling performance and drilling azimuth. The noise effect of various factors like bit type and condition was normalized so that the resultant output was expressive of azimuth effect.
The resultant heat maps act in the same manner as mechanical earth models (MEM) were used for wellbore stability studies. This occurs by suggesting the most appropriate azimuth to drill the well more efficiently in terms of time and power consumption. Python libraries were implemented for the sake of fast data processing with visually comprehensible output reports that were used for the planning of future drilling campaigns. These reports have ROP and DEXP graphed against well azimuth and inclination to magnify the effect of both horizontal earth stresses and attack angle of the bit. Although the output is conclusive in most cases, this is not the fact in all wells and further investigations are required.
The result of this research is very beneficial tool that can be used while planning directional trajectory of oil and gas wells to speed up the drilling operations and cutting the cost back. By allocating suitable targets to certain surface locations, the required horsepower to drill the well at the same ROP is reduced and the rig time at the same power is significantly cut.
A Numerical Investigation on Flow Induced Vibration of Flexible Risers in Tandem Arrangements
Authors: Periyal Arun , Ghoshal Ritwik , Joshi Vaibhav 
Published: October 2022

Abstract
In this work, a numerical simulation of flow-induced vibrations (FIV) of two tandem long flexible cylinders is performed. In this regard, a fluid-structure interaction solver that uses a partitioned iterative formulation for coupling between the nonmatching 3D fluid mesh elements and the 1D beam elements is carried out through conservative surface-to-line coupling and vice-versa. Simulations are performed for two identical cylinders with an aspect ratio of 350 and a mass ratio of 1.9 which are subjected to a uniform with a Reynolds number of 6400. Simulations are carried out for various gap ratios ranging from a low gap ratio of 8 to a very high gap ratio of 16. The displacement time history of both the flexible cylinders is computed in both cross-flow (CF) and in-line (IL) directions. It is observed that the FIV response of the upstream cylinder roughly resembles the typical vortex-induced vibration response of a single/isolated flexible cylinder. The upstream riser vibrates with lower amplitude as a result of high reduced velocity, away from the synchronization regime. However, due to the interaction of the downstream riser with the disturbed wake of the upstream riser, its amplitude is observed to be higher, indicating resonance with the vortex shedding frequency and high amplitude vortex-induced vibrations. The shielding effects experienced by the downstream cylinder due to the wake generated from the upstream cylinder and its concomitant effect on the response of the riser have been studied thoroughly for different gap ratios. Investigation on dominant frequencies, the trajectory of the riser, and flow analysis of the interacting vortices are also performed in this study.
A Reduced Order Parameterization of Random Wave Fields With Deterministic Wave Groups
Authors: Tang Tianning , Adcock Thomas A. A. 
Published: October 2022

Abstract
Under a linear model of gravity wave evolution the expected shape of large events is given by Quasi-determinism theory. However, nonlinear physics modifies the averaged shape of the largest events. In this study, we examine these nonlinear modifications to the averaged shape of the largest events for directionally spread random wave fields. We first compare these nonlinear changes from the extreme events in random wave fields with the nonlinear changes during the evolution of deterministic wave groups. We then explore whether it is possible to predict these nonlinear changes observed in random wave fields with only nonlinear wave group simulations. We applied a modified version of the wave group detection algorithm in [1, 2] to isolate the individual wave groups from random wave fields. We perform the nonlinear wave group simulations with the initial conditions matching these isolated individual wave groups extracted from linear random wave field. The nonlinear evolution of these isolated wave groups can predict the envelope contraction of averaged shape of extreme events in random wave fields quantitatively over a wide range of local steepness under current conditions. This suggests some statistical connections between the nonlinear evolution of deterministic wave groups and the evolution of the largest waves in the random wave fields.
Offshore Wind Farms and Isolated Oil and Gas Platforms: Perspectives and Possibilities
Authors: Mota Daniel dos Santos , Alves Erick Fernando , Sanchez-Acevedo Santiago , Svendsen Harald G. , Tedeschi Elisabetta 
Published: October 2022

Abstract
Single-cycle gas turbines operating at low-efficiency ranges due to redundancy concerns in offshore oil and gas platforms are responsible for considerable amounts of nitrogen oxides and greenhouse gas emissions in some countries. The abundant resource of offshore wind energy constitutes an extraordinary opportunity for reducing such emissions. However, new challenges are introduced when gas-powered generation is partially replaced by wind power. This paper investigates the possibilities provided by a centralized hybrid energy storage system (ESS) for addressing these challenges. It reviews frequency control concepts for isolated grids and discusses the analogous problem of power balancing within the ESS itself. A set of structures for control of the grid frequency and the ESS DC voltage are described and evaluated. All illustrated by results obtained within the frameworks of the Innovative Hybrid Energy System for Stable Power and Heat Supply in Offshore O&G Installation Project and the LowEmission Research Centre.
Enhancements of Computational Fluid Dynamics Analysis of Air Entrapment and Fluid-Structure Interaction During Plate Entry to Water Through VoF-Slip and Adaptive Discretization Schemes
Authors: Mucha Philipp , Jiang Minyee , Bay Raymond J. 
Published: October 2022

Abstract
A Computational Fluid Dynamics (CFD) analysis of air entrapment and structural response during flat plate entry to water is presented. Slamming loads remain of concern for the design of safe and efficient ships and offshore structures to ensure structural integrity during extreme. Besides ships with large bow flare or horizontal stern planes, slamming events also occur for fast small craft with stepped hulls. Ditching of airplanes and vehicle wading represent non-marine applications. The advance of computational methods in engineering has enabled fluid-structure interaction (FSI) simulations for slamming. A crucial task of solving the coupled fluid and structural problem is the accurate resolution of free surface dynamics and phase interactions between water and air. Numerical ventilation on the bottom plating can arise due to discretization issues and curtail the resolution of physical aeration effects. The study at hand was based on a Finite-Volume (FV) method and the numerical solution of Reynolds-averaged Navier-Stokes (RANS) equations. Emphasis was laid on numerical techniques to contain numerical ventilation whilst limiting the increase in computational cost. In doing so, adaptive discretization schemes were employed. Namely, model-based adaptive mesh refinement (AMR) and time stepping for both motions of bodies (rigid and elastic) and the free surface. Additionally, the underlying Volume of Fluid (VoF) method was enhanced through consideration of slip between water and air to improve air entrapment predictions. Comparison was drawn to a novel experimental analysis for which both structural responses and high-resolution imagery of aeration were available. It was demonstrated that above enhancements not only lead to better capturing of air entrapment and reduced numerical ventilation, but also offered more flexible modeling concepts and potential performance gains.
Correlation/Prediction of CO2 Solubility in Single-Salt and Multi-Salt Brines Using PR EOS Incorporated With Modified Alpha Functions and BIP Correlations
Authors: Chen Zehua , Yang Daoyong 
Published: October 2022

Abstract
Accurate prediction of CO2 solubility in brine is of high significance for carbon capture, utilization, and storage (CCUS); however, no generalized methodology has been made available to successfully tackle such a technical challenge. In this study, a pragmatic and robust technique has been developed and generalized to correlate the CO2 solubility in single-salt brines using the Peng-Robinson equation of state (PR EOS) together with the modified alpha functions and binary interaction parameter (BIP) correlations. A comprehensive CO2 solubility database is firstly built to cover a large range of temperatures, pressures, salt concentrations, while five different salts (i.e., NaCl, KCl, CaCl2, MgCl2, and Na2SO4) are involved. By integrating with the modified alpha functions and BIP correlations, such a generalized model is found to yield an average absolute relative deviation (AARD) of 5.24%, 5.82%, 7.64%, 6.04%, and 4.61% for the correlated CO2 solubility in the aforementioned five single-salt brines, respectively. Compared with the existing correlations, the PR EOS-based model is better than the existing OLI, SP 2010, and DS 2006 models but only slightly inferior to the PSUCO2 model under certain conditions. By combining a new BIP correlation, the newly proposed model has been extended to predict the CO2 solubility in multi-salt brines with an AARD of 7.21%. In addition to its simplicity and high accuracy, this new model can be used to not only determine other physical properties including density, enthalpy, and interfacial tension of CO2-brine systems, but seamlessly integrate with any reservoir simulators, allowing for accurately evaluating and predicting performance of CO2 enhanced oil recovery and storage capacity under various conditions.
Fatigue Performance of Thermal Spray Aluminium Coated Mooring Chains
Authors: Fernandez Jonathan , Arredondo Alberto , Albisu Beatriz , Exposito Aintzane , Rodríguez Elena , Arana José Luis 
Published: October 2022

Abstract
Corrosion-fatigue is the main damage mechanism of chains in permanent mooring systems. Fatigue loading is unavoidable, but corrosion can be mitigated or prevented; so, the impact of its reduction in the corrosion-fatigue damage mechanism is of great interest.
TSA (Thermal Spray Aluminium) coating has been applied for corrosion mitigation in mooring chains, typically at the splash zone, where higher corrosion rates are expected compared to those in submerged condition. TSA coating was first applied in mooring chains in 2001 at the Gulf of Mexico. This early experience of TSA demonstrated its effectiveness in preventing corrosion of top chains and led to several projects applying TSA in the same location.
However, TSA’s effect on the fatigue performance of mooring chains had not been investigated so far. The paper presents full scale fatigue test results of TSA coated mooring chains. Six fatigue tests have been carried out on 76 mm chain, which results show increased fatigue endurance relative to comparable fatigue test data of freely corroding chains in seawater. The results are statistically analysed and compared with all available test data of uncoated chains from Joint Industry Projects, in order to assess the effect of the coating in the fatigue strength of mooring chains.
Development of New Inhibited Spacer for Cementing Operation
Authors: Alkhalaf Sara , Al-Yami Abdullah , Wagle Vikrant , Al-Safran Ali 
Published: October 2022

Abstract
Spacers are a very important element to have good cement bonding and to ensure well integrity. Spacers are used to prevent the contamination of the cement slurry by removing such materials and pushing them ahead toward the surface to separate the drilling fluid from the cement slurry. During the cement displacement process, and once the clay formation is in contact with the water present in the cement slurry, shales will be swelled or cracked due to the hydration reaction or water adsorption.
Therefore, it is very helpful to make a spacer with efficient properties that help in protecting the clay formation from the water and prevent or minimize the hydration process by adding shale inhibiter to the spacer mixture formula. In this study, we will investigate the impact of KCL and a novel amine-based shale inhibitor on clay formation and investigate how these chemicals work to enhance spacer functions. The spacer has to be compatible with the drilling fluid and the cement slurry at the same time. Our study includes the compatibility test, rheology, thickening time test, as well as dispersion test for both KCl and novel amine based shale inhibitors.
Estimation of Design Slamming Loads From Laboratory Test of a Circular Cylinder
Authors: Lian Gunnar , Haver Sverre , Swan Chris 
Published: October 2022

Abstract
Slamming from steep breaking waves can give high impact loads, both globally and locally. In this study we quantify the difference between slamming loads in long-crested and short-crested seas by performing model tests in 11 different sea states. The q-probability slamming load is estimated from long-term analysis by utilizing a modified version of the all-sea state approach where we integrate over a limited domain of sea states. The selected domain includes the sea states that contribute most to the characteristic design value. This method is convenient if the response needs to be estimated by model testing in a limited number of sea states.
Hydrodynamic Analysis of a Triple Thruster Unit Via a BEM/RANS Interactive Method
Authors: Kim Seungnam , Kinnas Spyros A. , Grebstad Ray Thomas , Johannessen Jahn Terje 
Published: October 2022

Abstract
In this paper, a boundary element method (BEM) is used to predict the unsteady performance of ducted propellers in open water and ship behind conditions. The model propeller adopted includes the non-axisymmetric duct appendages (e.g., gearbox, brackets, and vertical structure connected to the hub), which induce severe shedding vortices on the propeller plane. This study thus investigates the effects of separation from the duct appendages as well as the upstream hull on the unsteady ducted propeller performance under different loading conditions. To improve the accuracy of a potential flow solver for highly viscous problems with separated flow near a blunt body, the present method is coupled with a viscous Reynolds-Averaged Navier-Stokes (RANS) solver. The former solves the ducted propeller problem to produce the propeller-induced flow field and body forces, with which the latter solves the total flow field based on a finite volume method. This approach is implemented in an iterative manner until the predicted 3D effective wake on the propeller surface becomes fully converged. An automated interface is developed to facilitate this process. A complete analysis of the propeller performance (i.e., predicted effective wake, flow-field, unsteady forces, and circulations on the blade) is presented at various operating conditions to investigate how the flow field inside and outside the nozzle is influenced by the viscous interaction among the incoming flow, propeller, its appendages, and upstream hull. For the sake of validation, the predicted results are compared with experimental measurements and results from unsteady full-blown RANS simulations. The presented results show satisfactory agreement among the results from different approaches, which makes the BEM/RANS coupling scheme adequate and computationally efficient for practical applications.
Development of a Geopolymer Cement for Primary Well Cementing: Method, Preparation and Particle Size Effect on Reaction Reactivity
Authors: Alanqari Khawlah , Al-Yami Abdullah , Wagle Vikrant 
Published: October 2022

Abstract
The global production of cement is the third largest source of CO2 emissions into the environment, which comes from the decomposition of carbonates. Geopolymer cements can reduce CO2 emissions by 64–80% compared to conventional cement (OPC). Moreover, geopolymer cements have demonstrated promising mechanical properties in comparison to conventional cements. We successfully developed a novel geopolymer cement utilizing a Saudi Arabian volcanic ash for primary cementing applications for the oil and gas industry. This novel cement was prepared by activating the volcanic ash particles with an alkali solution to undergo a geopolymerization reaction. The volcanic ash (VA) properties can be an obstacle for implementation such as particle size distribution. The objective of this study is to prepare a geopolymer cement with excellent strength and to investigate the effects of VA particle size distribution on the synthesis, setting time and mechanical properties of volcanic ash-based geopolymer cement. For this study, we used medium and fine ashes. For the fine ash, we investigated three different particle sizes (150 μm, 71 μm, and 45 μm). The compressive strength and thickening time were measured and performed at the estimated bottom hole temperature and pressure. Test results indicate that the resulting compressive strength is linearly affected by the average particle size distribution.
Experimental Study of the Drag and Wave-Induced Surge Forces on an Underwater Vehicle Operating Near the Surface
Authors: Suriben Kristia M. , Yeager Kathryn I. , Klamo Joseph T. , Kwon Young W. 
Published: October 2022

Abstract
This paper investigates the steady drag and oscillating wave-induced surge forces on an underwater vehicle caused by near surface operations. We experimentally measured the longitudinal forces on a submerged body with forward speed subject to single regular waves of various lengths. A circular cylinder body with hemispheric end caps was tested in a towing tank with wavemaking capability. Since the drag force is driven by viscous effects and flow separation, and to confirm if either of these affect the surge forces, we also tested the body with flat end faces to force flow separation at the leading edges. Our results show an increase in the calm water component of the drag force for the flat end face geometry and that both end shapes experience an increasing nonlinear wave-induced component of drag as wavelength increases. For the wave-induced surge forces, we observed that viscous effects and forward speed both play, at most, minor rolls as there was no significant difference between the surge forces on the two different end shapes or between stationary bodies and ones with forward speed.