bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of the Relation Between Coring Parameters and Formation Representation
Authors: Abugharara Abdelsalam , Butt Stephen 
Published: September 2023

Abstract
Coring is an essential operation for subsurface formation evaluation. It is a key to recover cores from formation and have them unaltered for best formation representation. Numerous reasons could influence core integrity that could produce data through core characterization that could misrepresent the formation. The aim of this paper is to investigate the influence of the (input vs. output) coring parameters and coring bit type on the coring performance and the cored formation property representation in high strength rocks. Such aim was investigated through coring operations applying Weight On Bit (WOB), rotary speed (revolution per minute - rpm), etc. In this research, high strength granite blocks were cored using a fully instrumented large-scale laboratory drilling simulator. Two main types of coring bits were utilized in the coring operations including a thick-wall coring bit and a thin-wall coring bit. The range of the applied WOB varied between a low weight (1kN) and a high weight (15kN) with increment increase of (2.5 kN). The applied rpm ranged between 60rpm and 300 rpm with increment increase of 60 rpm. Granite formation was characterized for rock property determination. The indirect Tensile (IT) Strength Test was conducted for the granite Material Characterization (MC). The analyzed and reported results of the overall coring performance, parameters (parameters vs. type of coring bit), and the IT for granite MC showed an influence of the un-optimized applied coring parameters and the random selection of the coring bit could remarkably impact the coring performance outcome and misrepresent rock property of the cored formation. Results recommend optimal selection of coring bit and applied coring parameters are essential for best coring performance.
Current Effect on Nonlinear Wave Height
Authors: Kumar Arun , Hayatdavoodi Masoud 
Published: September 2023

Abstract
Interaction of uniform and shear currents with nonlinear waves is studied by use of the computational fluid dynamics approach. A range of nonlinear waves are considered including shallow- and deep-water waves, and the effect of currents of variable speed and direction on the wave height is investigated. Uniform current consists of a fixed horizontal velocity across the water depth, while shear current imposes a linearly varying velocity from the seafloor to the still-water level. The current speeds are selected such that they remain comparable with the horizontal particle velocity under the wave crest and wave trough. A computational wave-current tank is developed for this purpose and the combined wave-current condition is obtained by developing a new wave-current maker in an open-source computational fluid dynamics package, namely OpenFOAM. The model is tested against laboratory measurements of various types of wave and currents and very good agreement is observed. The model is then used to investigate how currents of different profile, speed and direction modify the wave field. While the focus of the study is on the effect of these currents on the change of wave height, the surface elevation of the waves is also assessed in some cases. Discussion is provided on the differences between current effect on the wave height of shallow-water waves vs deep-water waves. The wave nonlinearity is found to play a remarkable role on how the wave changes under the ambient current. Shear currents are observed to have a stronger influence on the change of wave height than uniform currents.
Experimental Investigation on the Natural Frequency and Damping Coefficient of the Roll From Vessel Response in Random Seas
Authors: Javanmardi Mohammadreza , Mehr Javad A. , Heng Zi Hsiang 
Published: September 2023

Abstract
Autonomous shipping is inevitably the future of sea transportation which requires accurate decision-making systems. Analysis of big data as a key element to develop these decision-making systems is much easier than before. The precise prediction of vessel roll response, as a critical component of ship motions, by directly calculating hydrodynamic parameters from vessel response during the voyage, would tremendously aid in the real time adjustments to avoid dangerous situations the vessel would encounter.
This investigation aims to extract the natural period and damping coefficient of the roll from vessel response in random seas. Experimental tests were conducted to record the roll motions of vessel models, P&O Nedlloyd Hoorn container ship and Midi Mak Marad F bulk carrier, in random waves at Australian Maritime College Model Test Basin. The natural period obtained from the vessels’ roll response in random seas were in close agreement with the one obtained from the vessels’ roll decay test with negligible percentage error of under 1% for both models. Random Decrement Method (RDM) was used to produce roll decay from random vessel response and estimate the damping coefficient of the models. The estimated damping ratio from RDM show the good agreement with roll decay tests. This great achievement can help us to precisely predict the vessel roll response in random seas in order to avoid dangerous situation.
Impact of Chemical Impurities on the Integrity of Carbon Dioxide Transport Pipelines
Authors: Stokes Stephen , Haghighi Hooman , Mckay Craig 
Published: September 2023

Abstract
There are significant technical challenges to be addressed in the design of transportation pipelines for Carbon Capture and Storage (CCS) projects, not least of which is the management of non-carbon dioxide (CO2) components (impurities).
Typical impurities such as glycols (diethylene glycol (DEG) and triethylene glycol (TEG)), amines (ethanolamine (MEA), diethanolamine (DEA), methyl diethanolamine (MDEA)) and alcohols (methanol) could be potentially carried over during transient or upset operations from gas processing units to the CO2 pipelines. Furthermore, impurities (for example monoethylene glycol (MEG)) could remain in the system following pre-commissioning depending on the approach to pipeline dewatering and conditioning.
These chemical impurities, though in very low amounts, can trigger water dropout and lead to the presence of a free aqueous phase. CO2 and reactive components such as hydrogen sulphide (H2S), sulphur dioxide SO2, nitrogen dioxide (NO2) and oxygen (O2) can dissolve in free water and form stronger acids such as carbonic or sulphuric acids that can influence the operation and material integrity of CO2 pipelines. Particularly, the heavier corrosive acidic liquids can be stagnant at low points and increase the risk of localised corrosion.
This paper reviews the research that has been conducted to date on chemical carry-over, risks of acid formation and component solubility limits in CO2 streams. The research is applied to a practical example of a post-combustion CO2 gas gathering pipeline to demonstrate the importance of controlling minor impurities to a tight specification in the CO2-rich fluid.
A Numerical Study of Wave Impacts on a Semi-Submersible
Authors: Deng Yanfei , Li He , Wang Zixuan 
Published: September 2023

Abstract
A fully nonlinear numerical wave tank (NWT) is set up for extreme wave modelling and wave impact simulation. As a first step, a focused wave train was model and the focal location where the steep focused wave is close to breaking was determined. Subsequently, an in-depth investigation is performed on the wave impact loads on the wave-ward side of a deck box of a semi-submersible subject to this extreme wave. The numerical results are also compared with the predictions in accordance to the DNVGL technical guide. It is concluded that the severe horizontal impact loads are caused by the “strike” action of the rushing water mass from near-breaking waves rather than the run-up jets. The predictions based on the technical guide are conservative and in general overestimate the impact loads. These findings could contribute to a more comprehensive understanding and a more accurate algorithm with respect to the horizontal impact loads.
Development of Numerical Model of Floating Body With Air Chamber for the OWC-WEC Using Two-Phase Flow MPS Method
Authors: Sasahara Yutaro , Masuda Mitsuhiro 
Published: September 2023

Abstract
The floating oscillating water column type wave energy converter (OWC-WEC) is highly maintainable and safe because it has no moving parts underwater. For the commercialization of the floating OWC-WEC, a method is required to analyze, indepth, its response to waves over a wide range of wave conditions, from operational to survival conditions. In this study, the authors have developed a floating body model with an air chamber for expressing the floating oscillating water column by extending the high accuracy two-phase flow moving particle simulation (MPS) method. The MPS method is one of the particle methods used for computational fluid dynamics (CFD) simulations which can easily solve problems related to large free surface deformation and nonlinear fluid and structure interaction. Numerical and experimental investigations using the free heave decay test were conducted to confirm the validity of the developed model. A comparison of the numerical and experimental results showed that although a numerical pressure oscillation of particles increases as the power take-off (PTO) damping increased, both results generally agreed on the heave motion of the floating body, water mass height and air pressure in the air chamber, and the applicability of the proposed method was verified.
SHANSEP-Based Approach to Account for Consolidation Induced Strength Gain in Capacity Assessment of Shallow Foundations
Authors: Zhou Hongjie , Sun Chao , Krisdani Henry , Dias Helena 
Published: September 2023

Abstract
It is well recognised that soil strength increases with time due to consolidation under sustained foundation load. This is typically termed ‘consolidation strength gain’. Quantification of such beneficial effect on the foundation capacity, however, is not straightforward for design. In this paper a practical approach is described to account for this effect in the design of shallow foundations on seabed dominated by fine-grained sediments. This approach is based on the relationship of Stress History and Normalised Soil Engineering Properties (SHANSEP), and featured by a consistent procedure throughout the processes from soil characterisation to foundation capacity assessments. The SHANSEP relationship can be parameterised during the site characterisation stage and is used in the numerical modelling to estimate strength increase due to consolidation effects, which in turn is used in the capacity calculations of a mudmat foundation.
Data from a deepwater project is used to demonstrate the entire process. The beneficial effect of consolidation on the foundation capacity is illustrated through the expansion of the failure envelopes in the horizontal-vertical-moment load space. The magnitude of such effect is expected to vary between soils and interface conditions and be affected by the consolidation load and consolidation period. However, in general the horizontal and torsional capacities are expected to increase more significantly than the vertical and moment capacities.
Slope Effect on the Evolution of Kurtosis Over a Shoal
Authors: Mendes Saulo , Kasparian Jérôme 
Published: September 2023

Abstract
Shoaling surface gravity waves induce rogue wave formation, but are reduced to water waves passing over a step. We show that non-equilibrium physics allows finite slopes to be considered in this problem. A spatially varying energy density describes the dependence of the rogue wave amplification as a function of the slope steepness. Increasing the slope increases the amplification of rogue wave probability, until this amplification saturates at steep slopes. In contrast, the increase of the down slope of a subsequent de-shoal zone leads to a monotonic decrease in the rogue wave probability. In view of the central role played by the excess kurtosis in estimating rare event probabilities, we find an effective theory for the excess kurtosis evolving over a shoal.
The Sidetracking Configuration Optimization and Detailed Scheme Design in a Oilfield Middle East
Authors: Nie Zhen , Shi Shuzhe , Du Zhengxue , Huang Xueqin , Wu Bohong , Wang Chunpeng , Zhang Yanna 
Published: September 2023

Abstract
Sidetracking horizontal wells is a significant technology in the oilfield development industry. It can be applied in repairing abandoned wells, low production wells, casing damaged wells, and severe water breakthrough wells. This technology has advantages for the developed reservoir, for example, re-boost the production of the existing shut-off wells, prolonging the life of oil wells, and achieving the purpose of reducing costs and increasing efficiency. The recovery rate of the A oilfield main reservoir is about 10%, the producing water has fully broken through in A oilfield. The water cut in some areas is higher than 80%, and more than 55% of the production wells have a water cut higher than 70%. The overall water cut rises rapidly, which makes water control difficult.
Therefore, the sidetracking horizontal well technology is urgently needed in this A oilfield middle east, and a well-designed sidetrack configuration needs to be studied for the purpose of reducing water cut and re-boost oil production. In this work, reserves of each candidate layer of the reservoir have been evaluated to determine the best layer. Then, investigate the kick-off point locations and the specific sidetracking point locations to better design the sidetrack parameters, which is the most crucial section for oil production improvement and cost efficiency. One sidetracking well case is selected by applying the optimized parameters, and the detailed sidetrack plan was also designed, the numerical simulation was done to predict the production performance and complete the economic evaluation.
This work can add value to re-boosting the oil production of the poor-performance wells in A oilfield, and also provides theoretical support for future sidetrack drilling wells in other oilfields Middle East.
Ultrasonic Well Integrity Logging Using Phased Array Technology
Authors: Johansen Tonni Franke , Buschmann Philip Erik , Røsberg Knut Marius , Diez Anja , Viggen Erlend Magnus 
Published: September 2023

Abstract
Ultrasonic well integrity logging is an important and common procedure for well completion and plug-and-abandonment operations. Typical logging tools employ single-element ultrasound transducers. In medical ultrasound imaging, however, more flexible phased arrays are the standard. This paper presents a first set of experimental results obtained with up to two linear 32-element phased arrays that are specifically designed for plug-and-abandonment operations in terms of their centre frequency. The experiments encompass pulse-echo and pitch-catch studies for different incidence angles and aperture sizes on plates and pipes with wall thickness as encountered in the offshore industry. The pulse-echo experiment is backed up by simulations, and shows that effect of the incidence angle on the pipe resonance’s frequency and strength is weak and more strong, respectively, and that the effect depends on the frequency response and directivity of the transducer. The pitch-catch experiment demonstrates the importance of carefully choosing the right angle of incidence to excite the intended wave modes.
Well Integrity Operations Experience Transfer Using Long Short-Term Memory (LSTM) Recurrent Neural Network
Authors: Semwogerere David , Pavlov Alexey , Sangesland Sigbjørn 
Published: September 2023

Abstract
Well integrity is critical throughout the lifecycle of a well. During well operations especially for new fields, inexperienced engineers encounter many well integrity challenges which require a fast-learning curve. This ranges from downhole problems such as lost circulation and kicks to equipment damage due to lack of experience during installation, etc. The success of well integrity as a criterion in wells operations therefore heavily depends in the experience of the humans involved. For offshore operations this lack of experience can translate into very expensive consequences in case of loss of well integrity. Damaged equipment, lost time, injury to personnel and contamination of the environment are some of the consequences of blowouts. In oil and gas well construction and service operations petabytes of data in form of logs, reports and other sensor data are generated which contain vast information. By using machine learning and other statistical data analytic techniques on the data, insights on well integrity can be generated.
While yet most well data analytics focuses more on the numerical indicators of well integrity for example pressure, temperature, and casing thickness, text in well integrity reports gives elaborate description on the nature, context and experience applied in well integrity problems encountered. It’s important to transfer this experience in a faster way to the next well operation without laboring through the unstructured data repositories by using advanced text analysis. This smoothens the learning curve for the engineers, saving costs and improving well integrity.
In this paper, a language model for experience transfer using the Long Short-Term Memory (LSTM) recurrent neural network that reads well integrity problem description text from a report and classifies it into a root cause is proposed. It is benchmarked against the state-of the art Bidirectional Encoder Representation from Transformer (BERT) model. The pitfalls of current state of the art language models in processing datasets of oil and gas well operations text are discussed using the Volve end of well reports as an example.
Parametric Study of Umbilical Cable and Mooring Line Dynamics With Nonlinear Wave Propagation in Varying Sea Conditions
Authors: Kim Bruce , Adami Nasim , Chen Ming , C. Yim Solomon 
Published: September 2023

Abstract
Majority of the wave energy converters (WEC), especially buoyancy-based point absorbers, are designed to operate in high sea states maximizing energy extraction. Most WEC simulation tools use linear wave theory to analyze the wave field, which could lose accuracy under high sea state conditions. A parametric study is conducted to investigate the effects of the nonlinear wave propagation modeling on WEC responses. The nonlinear Schrödinger (NLS) equation was implemented to develop a nonlinear propagation model. The NLS-based model captures cubic nonlinear phenomena such as extreme sea conditions caused by modulation in wave envelope, which is a critical factor in the survivability of WEC systems. Also, to improve response analysis, mooring/cable system dynamics were represented with a bending stiffness module (MDB). This study was completed using a Reference Model 3 (RM3) WEC system in the National Renewable Energy Laboratory’s (NREL) Wave Energy Converter Simulator (WEC-Sim) in MATLAB. New modules have been built as open-source code to be used in conjunction with the latter, giving more modeling options to the end user and help developing more realistic assessments of a WEC or other floating system in their chosen sea state and location. The model was first subjected to an arbitrary regular wave to prove the interoperability of the two modules and measure initial effectiveness. The presented analysis highlights the differences in the response of the RM3’s system from existing models based on linear wave theory that do not include NLS and MDB in their calculations.
UUV Target Tracking Method Based on High Order CGHF Algorithm
Authors: Zhang Kai , Wang Hongjian , Huang Weiquan , Huang Shihao 
Published: September 2023

Abstract
The delay in the signal detected by sonar due to the limited speed of sound, in unmanned underwater vehicle (UUV) bearing-only target tracking with signal propagation delay, Cubature Gauss-Helmert Filter (CGHF) is often used for target tracking. CGHF uses the third-order Spherical-Radial Cubature Rule (SRCR) to calculate the Gaussian weight integral. Because underwater target tracking is a highly nonlinear system, third-order SRCR has only third-order Taylor expansion term accuracy, the tracking error of CGHF algorithm is large. Aiming at the problem that third-order SRCR has only third-order Taylor expansion term accuracy, a CGHF algorithm based on high-order SRCR is proposed in this paper. In this paper, the state model of Gauss-Helmert model (GHM) is established, the state of the model includes the signal transmission time. The measurement model of underwater target tracking is also given. Based on the GHM model, a new high order CGHF (HOCGHF) is derived by using higher order cubature points. In this paper, a method of evaluating the tracking accuracy of underwater targets and setting the initial filter value is given. Two kinds of underwater target tracking scenarios with different nonlinear degrees are established. The simulation results show that HOCGHF algorithm can effectively track the target in two different underwater target tracking scenarios, and has higher tracking accuracy than the existing methods.
Shape Optimization Design of a Heaving Buoy of Wave Energy Converter Under Bimodal Spectral Waves Near Islands and Reefs
Authors: Huang Shuo , Liu Wei-qi , Wang Kai 
Published: September 2023

Abstract
Wave Energy Converters (WECs) have been developed to advance marine energy technologies towards commercialization. The choice of geometrical shape for WECs is of great importance for increasing energy capture. The characteristics of wave spectrum will be provided with bimodal characteristics when waves propagate from deep water area to the area near the islands and reefs. This variation of the wave spectrum must be considered for the optimization of the WECs placed near islands and reefs. Nevertheless, no standard and consistent method has been established for this purpose yet. The novelty of the present study lies in optimizing the shape of a WEC for maximizing its mean annual absorbed power under bimodal spectral waves when using a flexible geometry definition, such as FFD method. The optimization object is based on a heaving buoy that considers a linear PTO system. The objective of the optimization is to maximize the mean annual absorbed power. The optimization process is proposed by using NSGA-II. A numerical analysis framework based on potential flow theory is presented for determining the mean annual absorbed power under bimodal spectral waves. The results obtained using this method significantly improve the computational efficiency compared to those using CFD method. Thus, this paper provides a guidance for the design of the optimization of the heaving buoy under bimodal spectral waves.