bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monitoring and Diagnostic System for Dry-Type Transformers Using Machine Learning Techniques
Authors: Martins F. G. R. , Lopes Y. , França B. W. , Ferreira V. H. , Sotelo G. G. , Augusto A. A. , Colombini A. C. , Pinho A. C. , Mello M. , Costa M. C. , Nogueira C. S. C. , Silva N. da , Melo A. , Soares A. , Fernandes D. 
Published: October 2023

Power transformers are recognized as high-value assets in substation design, but their susceptibility to various failure modes poses a significant risk of damage and power supply disruptions. Consequently, extensive research has been conducted to develop diagnostic techniques and monitoring methodologies for these devices. This project aims to develop a comprehensive solution comprising hardware and software components for the online diagnosis of dry-type transformers, primarily focusing on the detection of Inter-Turn Short Circuits (ITSC) in conjunction with Partial Discharge (PD) signatures.Dry-type transformers utilize ambient air as both a cooling and insulating medium. Among its advantages, the most relevant for the oil and gas industry are the lower maintenance costs and the absence of flammable oil, ensuring lower fire risks, which is a critical factor in facilities. As offshore electrical plants grow in complexity, there is an increasing demand for dry-type transformers with higher power ratings. Effectively monitoring the operational condition of such transformers serves as a strategic tool to enhance the reliability, robustness and safety of the electrical system, while potentially reducing overall maintenance expenditures.Such transformers offer notable advantages in terms of safety and reliability [1]. However, they come with higher costs and have lower power and voltage limits. Similar to any other equipment, transformers experience aging as a natural consequence of their operation. Its most significant consequence is the gradual degradation of insulation due to thermal effects and mechanical stresses resulting from electromagnetic interactions between windings turns. Additionally, transformers are susceptible to short-circuits, which induce intense electromechanical stresses in the windings, as well as overvoltages stemming from maneuvers such as line energization or the presence of inductive or capacitive loads. These factors elevate the dielectric stress on insulating materials and connections, potentially surpassing their design limits.
Extracting Textural Parameters from Image Logs to Enhance Reservoir Rock Typing in Diagenetic Controlled Siliciclastic Reservoir
Authors: Aguilar C. , Salazar F. , Jimenez J. 
Published: October 2023

Abstract
Image logs are appreciated by the geoscientists community due to they recognize important geological features such as sedimentological structures and structural patterns leading to enhance reservoir descriptions. Nevertheless, their quantitative use for petrophysical purposes may be underestimated. Incorporating high resolution information is vital for reservoir description whether depositional environment causes high heterogeneity, diagenetic process, and thin reservoir layers (reducing vertical permeability and acting as flow barriers reducing vertical sweep efficiency). Usually, thin sand layers are under conventional logs vertical resolution therefore they are not able to capture reservoir properties. On the other hand, cores offer direct high-resolution information, but they are expensive and only a limited number of samples are available. In this context, it is a crucial step to relate geological and petrophysical features (i.e.: sedimentary facies, lithology, permeability measurements…) from core to log domain using appropriate machine learning algorithms for clustering analysis.
In this paper, an automated high-resolution classification process based on textural parameters extracted from microresistivity image logs was successfully performed. Machine learning (ML) algorithm chosen to recognize and order texture was MRGC (Ye, et al., 2000; Rabiller, et al., 2001). Textural model is defined by first and second order moments of image. Due to its high resolution, microresistivity borehole imaging provides valuable information involving grain size, sorting and porosity distribution. Moreover, in laminated reservoir zones with diagenetic complexity, where conventional logs overlooked some thin prospective intervals, this approach revealed reservoir characteristic that directly impacts on reservoir management decisions. As a result of the application of this approach, improved spatial resolution of the rock type classification yielding a more detailed and comprehensive characterization of the reservoir and enhancing geocellular model. Thus, this approach has the potential to locate bypassed oil, maximize oil recovery reserves, minimize risks and thereby saving significant costs.
Controlled Removal of Sun Coral in Drilling Units Hull
Authors: Brancaccio G. R. , Lagraf D. , Pimentel L. O. 
Published: October 2023

Abstract
Biological invasion (bioinvasion) is a major socio-environmental threat that impacts biodiversity, due to the ease of dispersal and competitive advantage, and also impact the surrounding population and activities such as fishing and tourism. The sun coral is one of the marine bioinvasive species in Brazil and its control and monitoring requires constant cleaning of the hulls of ships and semi-submersibles used by oil and gas drilling companies.
While the call for hull cleaning is not new, in the last two years, new rules and standards have been introduced in Brazil for cleaning specifically directed at exotic species. In addition, many hull cleaning technologies are known but not yet applicable to the removal of sun coral from hulls.
As a result, the removal of its biofouling is now one of the main challenges of drilling contractors working in Brazil. The call for the removal of sun coral from hulls is growing every day, and since the cleaning operation is costly and time-consuming, it has received considerable attention and has been the subject of studies to optimize it. Cleaning a hull involves the utilization of diving teams, in a manual and high-risky activity, for the lack of other applicable technology. In this sense, the objective of this paper is to present a bibliographic review on the subject, and to present a case study of the hull cleaning activity of four offshore drilling rigs for the controlled removal of fouling biota by sun coral.
This paper is based on a case study of the controlled removal of sun coral using diving teams, from four (4) drilling units, three (3) semi-submersible and one (1) drillship, performed in 2022 in Guanabara Bay, Rio de Janeiro. The data analyzed were live area worked, duration of the cleaning operation, number of teams, average number of teams per day, and area worked per day.
The acquired data may be useful for planning future maneuvers for the removal of exotic species, as well as the cleaning of biofouling from the living works of offshore drilling units, as it presents comparable data and similar activities.
Lessons Learned from Constructing Atlanta Field Wells: A Milestone in the Deepwater Offshore Oil Industry
Authors: Pedroso C. A. 
Published: October 2023

Abstract
The successful commercial exploitation of the Atlanta field, the world's first ultra-deepwater heavy oil project, is a milestone in the offshore industry. The technological solutions and innovations applied so far, allowed the Early Production System (EPS), which at first would be a big prototype for studying technical solutions and understanding the behavior of the reservoir and aquifer, to become a standalone project. With this, the EPS was extended, and a fourth well was added to the initial 3-well design.
The success of production, which has already accumulated 25 million barrels of oil produced, confirmed the performance of the large aquifer, simplifying and reducing project costs, but has caused significant dynamic depletion in the vicinity of producing wells. Currently, the powerful ESP into the producer wells apply a drawdown of approximately 120 bar, certainly one of the highest in the world. The robustness and correct design of the sand control used in the wells has allowed this operation.
This depletion added additional challenges to the construction of the 4th, 5th and 6th wells and an even narrower operating window was expected. To deal with these uncertainties, the drilling operations included a new determination of the geomechanical properties of the reservoir. Also, the OHHGP with AICD used 3 different proppants, with density of 2.71g/cm3, 1.34g/cm3 and 1.08 g/cm3, the latter being the first use in OHHGP. Also 3 fluids were used in the OHHGP
Lessons learned and the innovations that allowed the construction of the 4th EPS well, such as this pioneer OHGP operation, are depicted in this paper.
Digital Twin of Subsea Assets as a Tool for Integrity Management and Risk-Based Inspection: Challenges and Perspectives
Authors: Rodrigues S. S. , Braga J. O. , Xavier J. M. , Pauli G. , Mata A. M. , Margotti E. , Demay M. B. , Donatelli G. D. 
Published: October 2023

Abstract
Based on the current applications in the oil and gas industry, this paper approaches the main challenges in the development of a Digital Twin for subsea production system assets. Bibliographical research was carried out to select relevant digital twin solutions developed in the different sectors of the oil and gas industry, in order to identify the main challenges, risks and prospects for implementing this type of technology. Furthermore, this manuscript also provides solutions developed by the authors based on the experiences in research, development and innovation of national projects for digital transformation. These solutions contemplate data analysis, connections with databases, definitions of recurrent degradation models in the oil and gas industry. A digital twin can be defined as the digital representation of a system or asset, which calculates states and provides relevant information through integrated models and data, to support decisions throughout the life cycle. In the upstream, whose main activities involve the exploration and production of oil and gas, digital twin can be used as a tool for asset integrity management in the production system and associated with integrity management methodologies such as Risk Based Inspection (RBI). The implementation of a digital twin is a complex task and has several challenges, since it is composed of many models and data that need to be interconnected. However, it is common for data from different sources to be stored on different systems. Another relevant challenge concerns the models associated with digital twins, which are sources of uncertainties. The lack of consistent models and coordination between current physical and virtual models, complex data validation, collection and processing challenges are obstacles in implementing a digital twin. If well implemented, the digital twin can help in the decision-making process related to asset integrity management by following the asset throughout its life cycle. In an RBI approach, it can reduce the OPEX cost of subsea systems. This paper will approach the stages of the development of a digital twin for subsea production systems assets and the main challenges based on recent studies carried out in the oil and gas industry such as the requirement for transparency in data exchange while maintaining security and confidentiality, data-model assimilation, uncertainty and validation of models. In addition, it will be presented the experience acquired by the authors in the development of solutions for integrity management.
Experimental Study of Creep Behavior at High Temperature in Different HMPE Fibers Used for Offshore Mooring
Authors: da Cruz D. M. , Barreto M. A. , Zangalli L. B. , Júnior T. L. Popiolek , Guilherme C. E. M. 
Published: October 2023

Abstract
Offshore moorings have been extensively researched in recent decades, and since the introduction of Taut-Leg systems made with synthetic polyester fibers as an alternative to steel catenaries, several fibers have gained significant prominence. High modulus polyethylene (HMPE) stands out due to its superior mechanical resistance and linear tenacity compared to many other fibers. However, it shows challenging behavior in creep, showing high strain rates and low creep resistance. Consequently, manufacturers have focused on developing HMPE fibers typified as "Low Creep," aiming to achieve satisfactory creep behavior and enable offshore mooring systems made entirely of HMPE. Such advancements could lead to the use of HMPE in offshore installations in ultra-deep waters, given its low elongation. The goal of this study is to evaluate the creep behavior of 6 HMPE fibers, including both European and Asian manufactures, with 3 fibers designated as "Low Creep." The evaluation encompasses different load temperature conditions. The experimental approach uses HMPE multifilaments, which serve as the base material for making mooring ropes. The results are compiled in tables, providing initial characterization results and average creep results, including creep strain rates. Creep graphs are drawn to facilitate understanding and comparison of the behaviors, along with a generalized statistical modeling of the creep-rupture surface for each fiber. The results show that the fibers designated as "Low Creep" indeed exhibit significantly better behavior than others, with lower strain rates. Among them, Fibers A and D emerge as the most promising for offshore mooring, showing greater resistance to creep. From a commercial standpoint, Fiber D offers the lowest cost per kg and presents favorable constitutive behaviors in specific operational contexts, as well as better stability with increasing temperature. In terms of future directions, other methodologies linked to the acquired experimental database should be explored, including analytical models and numerical simulations. Additionally, an investigation into sub-ropes and a detailed study of thermal degradation decoupling in the studied phenomenon should be considered for further research.
An Innovative ML Methodology for Property Modeling (EMBER): A Case Study in Buzios Field, Brazil
Authors: Ferreira1 D. J. A. 
Published: October 2023

Abstract
The application of the Embedded Model Estimator (EMBER) petrophysical modeling algorithm allowed for the determination of effective porosity and permeability in the presalt carbonate reservoirs of the Barra Velha Formation located in the Buzios Field, Santos Basin. This sophisticated approach was necessary due to the complex and heterogeneous nature of these reservoirs, which posed challenges for traditional geostatistical methodologies. Effective porosity was modeled using a combination of secondary variables including a facies model, a stratigraphic seismic attribute (acoustic impedance), and a structural seismic attribute (local flatness). Permeability was modeled using the most accurate simulation results obtained for effective porosity. Our findings indicate that the average effective porosity and permeability values were 0.10 v/v and 440 millidarcies (md) respectively, indicating favorable reservoir quality across the entire study area. An analysis of the reservoir properties revealed a vertical trend characterized by a basal section and uppermost section exhibiting high effective porosity and permeability, while an intermediate section displayed lower reservoir properties. The lower section of the formation exhibited greater continuity and is inferred to be the most favorable reservoir interval. The correlation between the modeled results and the blind-test ANP-1 well upscaled properties was found to be significant, demonstrating the predictive capability of the employed algorithm. Furthermore, the EMBER simulations successfully preserved the distribution of upscaled well log properties, further validating the algorithm's accuracy. Finally, an analysis of conditional distributions indicated that the estimation of effective porosity in the basal section of the Barra Velha Formation is subject to higher uncertainty. Therefore, although this interval is considered to possess the most favorable reservoir characteristics, caution should be exercised when making decisions regarding this specific reservoir section.
New Strategy Focused on Costs for Drilling with Losses When Using MPD
Authors: Sales I. M. , Silva R. L. M. , Feijo J. L. Q. 
Published: October 2023

Summary
Drilling wells in the pre-salt always poses a major operational challenge, directly related to the formation itself and, therefore, inherent to the scenario: fluid losses in carbonate reservoirs.
Due to secondary porosity, pores of varying sizes and distribution are found, which can be small or large, such as in vugs and caves. In addition to secondary porosity, there may be fractures or even microfractures in regions of the reservoir due to the stresses generated by the evaporitic rock structure above the reservoir.
All these characteristics of the pre-salt carbonate reservoir bring a major operational obstacle, which is the circulation loss.
To mitigate these losses or cope with them, different strategies are used, such as having large volumes of drilling fluid available, using Loss Control Materials and/or using Managed Pressure Drilling (MPD). It is important to consider that all these approaches bring additional costs to the operation and can be combined with each other to have the best performance, both in terms of time and cost.
In addition to the financial impact, drilling with losses brings some risks, such as: stuck pipe on account of poor cleaning, kick following a drop in the fluid level in the annulus, fluid exhaustion due to inefficient logistics, among others.
When drilling with MPD, the risks mentioned above are mitigated and the well is better monitored. Thus, the strategy to cure losses in wells with MPD must be reviewed, since, once the risk to well integrity is mitigated, decisions must be based on the strategy that generates the lowest cost.
This article proposes a new vision on the strategy to mitigate losses in wells with MPD, discussing the criticality of losses for well integrity, and recommends a more objective procedure of proposing strategies and decision trees for drilling with fluid losses.
Effects of Silicondioxide Nanomaterial in Enhancing the Performance of Water Based Drilling Mud
Authors: Bataee M. , Rehman A. A. , Rostamian A. , Serasa N. A. S. , Ashena R. , Hamdi Z. 
Published: October 2023

Abstract
With the current high energy demand, oil and gas companies are increasingly exploring unconventional reservoirs. However, these reservoirs pose environmental challenges that hinder conventional drilling fluid usage. This is where nanomaterials come into the picture, offering a solution due to their unique size. Nanomaterials prove effective in overcoming harsh environmental conditions, including high temperature and pressure, enabling the production of oil and gas from these challenging reservoirs. The objective of this study is to investigate the impact of silicon dioxide on water-based drilling fluid properties. Initially, a base mud was formulated with careful consideration of solvents to ensure proper dispersion of silicon dioxide. The aim was to achieve complete and homogeneous dispersion of silicon dioxide within the base mud, thereby examining its effects. The findings indicate significant improvements in the water-based mud properties with the inclusion of silicon dioxide. These enhancements include an 18.6% reduction in plastic viscosity, a 31% increase in yield strength, a 25% increase in gel strength, an 18.6% reduction in fluid loss, and a 19.04% reduction in mud cake thickness. The exceptional results stem from the unique structure of silicon dioxide, which demonstrates the potential to elevate water-based mud performance to levels comparable to oil-based mud. The environmental drawbacks of oil-based mud have already been established, coupled with its higher cost compared to water-based mud. However, if water-based mud can achieve comparable effectiveness to its oil-based counterpart, it would lead to a reduction in pollution and significantly lower operational expenses.
Electrification of Offshore Platforms to Reduce Carbon Footprint and Achieve Lower Operational Expenses: A Feasibility Study
Authors: Teixeira A. M. , Bassani G. S. , Maia J. G. S. S. , Interlenghi S. F. , Santos D.S.D. , Novaes L. , Junior R.L. , Marin A. , Rossi J. , Alves R.M.B. , Bresciani A. , Andreotti M. , Hurtado M. 
Published: October 2023

Abstract
Electrification with the use of clean electricity is seen as a key alternative to lower CO2 footprint of E&P sites. In this sense, renewables can be used to generate power onshore which is treated in substations that can be grid-connected and transmitted to offshore fields via submarine transmission cables. The objective of this work is to evaluate the economic feasibility of generating onshore low-cost electricity from renewables and transmitting it to offshore platforms.
This work describes a model for optimizing a renewable energy system based on solar photovoltaics and/or wind energy, where solar and wind profiles are generated according to a described methodology. The model is based on hourly energy balances to account for periods with insufficient energy offer, where power from the grid is used as complement. For a certain grid electricity price, there is an optimum between renewable power generation capacity and grid power consumption. The model calculates the respective size and investment necessary in the renewable power system that minimize overall costs, as well as carbon emissions associated with grid use. The described methods are applied to evaluate the electrification of offshore platforms in the Pre-Salt region using renewable power from shore and comparing with traditional in-situ power generation from fossil fuels. The onshore substation with transmission costs and associated losses are considered to evaluate the levelized cost of electricity (LCOE) of a platform located at several distances from shore, where LCOE rises as the distance from shore increases.
The analysis reveals the existence of a break-even point where the LCOE from onshore power generation using renewables is equal to the LCOE from conventional in-situ power generation using fossil fuels. Moreover, the incorporation of a carbon penalty for CO2 emissions increases this break-even distance, emphasizing the importance of implementing incentives or policies designed to reduce emissions. In this sense, carbon taxes or other carbon pricing mechanisms enhance the competitiveness of the alternative employing renewable power from shore in comparison to in-situ power generation from fossil fuels.