bluuebunny/crossref_metadata_2025 huggingface dataset:
Factores asociados al uso de anticonceptivos hormonales en puérperas inmediatas atendidas en el Hospital Nacional Daniel Alcides Carrión 2024
Authors:   , Padilla Ortiz Richard Martin , Paucca Huamancha Jorge Luis
Published: February 2025

Objetivo: determinar los factores sociodemográficos asociados al uso de métodos anticonceptivos hormonales en puérperas inmediatas atendidas en el Hospital Nacional Daniel Alcides Carrión en 2024. Materiales y Métodos: Se realizó un estudio observacional, transversal y analítico, con la participación de 222 madres puérperas inmediatas. El análisis de los datos se llevó a cabo utilizando el software estadístico IBM SPSS versión 26.0. Resultados: El 51.4% de las madres que usaban anticonceptivos hormonales tenía entre 20 y 29 años, el 54.1% alcanzó el nivel educativo de secundaria, el 65.8% convivían con sus parejas, y el 62.2% eran amas de casa. El 88.3% de las madres tenía entre 1 y 2 hijos, el 76.6% recibió asesoramiento sobre planificación familiar durante los controles prenatales (APN), y el 61.3% tenía entre 1 y 5 años de relación de pareja. Además, el 76.6% de las madres tenía un bajo nivel de conocimiento sobre el uso de anticonceptivos hormonales, y el 88.2% presentó al menos un efecto secundario relacionado con su uso, los factores que se asocian con el uso de anticonceptivos hormonales fueron la edad menor a 19 años (RPa= 1.602, IC: 1.121-2.290, p=0.010) y 20 a 29 años (RPa= 1.422, IC: 1.068-1.893, p=0.016), mujeres con 1 o 2 hijos (RPa= 3.220, IC: 1.928-5.378, p=0.000), y el uso de MAC en el entorno (RPa= 1.104, IC: 1.021-1.193, p=0.013). Conclusiones: Entre las puérperas inmediatas, se identificaron factores que se asocian significativamente con el uso de anticonceptivos hormonales: la edad, nivel educativo, número de hijos y uso de MAC en el entorno.
Prevalencia de enfermedades dermatológicas en rostro por uso de mascarilla y factores asociados en internos y residentes en actual desempeño en instituciones de salud de una universidad privada en Lima metropolitana
Authors:   , Delgadillo Arcega Greshia Valentina , Cayo Antunez Ashly Lizbeth
Published: February 2025

Introducción: Durante la pandemia de COVID-19, el uso de mascarillas fue crucial para evitar la propagación del virus, pero generó efectos dermatológicos en el personal de salud. Entre las afecciones más comunes se encontraron acné, rosácea y dermatitis de contacto irritativa (DCI), asociadas con factores como alteración de la microbiota cutánea y mayor sensibilidad dérmica. Método: Se realizó un estudio observacional, descriptivo y transversal en 228 internos y 80 residentes de una universidad privada (agosto 2023-enero 2024), con muestreo probabilístico aleatorio y un nivel de confianza del 95%. Mediante encuestas, se evaluaron el uso de mascarillas, antecedentes dermatológicos y el desarrollo de lesiones cutáneas. Resultados: El 63.5% reportó lesiones cutáneas tras usar mascarillas quirúrgicas, KN95, N95 y P100. En casos de acné, el 65.62% eran mujeres y el 93.75% internos de Medicina Humana. El 62.62% usaba mascarillas quirúrgicas o KN95 más de 12 horas al día, cambiándolas cada 14-16 horas. La rosácea fue más frecuente en personas sin antecedentes dermatológicos, con un 69.44% que usaban mascarillas más de 12 horas diarias. En casos de DCI, el 71.7% eran mujeres, el 69.81% internos, y el 90.6% conservaba correctamente las mascarillas. El 92.5% de los afectados no tenía antecedentes dermatológicos. Conclusiones: El estudio demuestra que el uso prolongado de mascarillas durante la pandemia de COVID-19 está relacionado con el desarrollo de afecciones dermatológicas como acné y rosácea en trabajadores sanitarios.
Efecto de dos agentes inhibidores de oxígeno sobre la microdureza superficial de materiales restauradores giomeros
Authors:   , De La Cruz Llanos Diana Jimena
Published: February 2025

Los giomeros son materiales restauradores híbridos bioactivos, constituidos por resina compuesta y relleno de ionómero de vidrio pre-reaccionado en superficie, mantienen cualidades clínicas aceptables en el tiempo; un factor principal para ello es la dureza superficial que se logra inhibiendo la capa de oxígeno. Objetivo: Comparar el efecto entre la Tira Mylar azul y convencional al ser utilizados como agentes inhibidores de oxígeno sobre la microdureza superficial de los materiales restauradores Giomeros¬¬¬. Material y Método: Se confeccionaron un total de 96 muestras de giomeros en una matriz en forma de disco, de 2 x 5 mm de diámetro (ISO 4049: 2019-05). Se agruparon las muestras según el tipo de giomero: Beautifil II (BII) y Beautifil II LS (BIILS), y según el tipo de tira mylar: convencional, azul y el grupo control sin tira. Posteriormente fueron sometidas a prueba de microdureza Knoop (KHN). La base de datos fue analizada con el software estadístico Stata SE v18, se realizó la prueba ANOVA de dos factores. Resultados: Se encontró interacción entre el tipo de giomero y de tira mylar (p=0,039), y también diferencias significativas entre los valores de microdureza superficial según el tipo de giomero (p=0,001) y según el tipo de tira mylar (p=0,001). Beautifil II LS presentó diferencias significativas entre Tira Mylar Convencional vs sin Tira Mylar (43,58 ± 1,65 vs 40,44 ± 2,12) y entre Tira Mylar Azul y sin Tira Mylar (44,69 ± 1,75 vs 40,44 ± 2,12). En la prueba Post hoc de Bonferroni se encontró diferencia significativa entre Tira Mylar Convencional y sin Tira Mylar (p=0,001) y Tira Mylar Azul y sin Tira Mylar (p=0,001). Conclusión: El uso de las tiras mylar azul y convencional inhiben...
New Efficient Drillstring-Wellbore Contact Model Makes Real-Time BHA Directional Estimation Possible
Authors: Wilson J. K.
Published: February 2025

Reliably predicting directional tendencies of downhole drilling assemblies has been an interest of researchers for decades. Initial efforts focused primarily on accuracy in calculation, attempting to account for the various nonlinearities that exist downhole (geometric coupling, wellbore contact, friction, etc.). As bottom-hole assembly (BHA) mechanics models have improved to capture these inherently nonlinear behaviors of the downhole system, focus has naturally shifted to improving calculation efficiency and reducing the time required to obtain results. With the continued adoption of automated technology, a fast and reliable method for performing these calculations is even more critical.

A new directional prediction algorithm is developed, in combination with an efficient drillstring-wellbore contact model, which drastically reduces these calculation times and helps address the challenge of balancing accuracy and efficiency. The algorithm uses a newton iteration approach to estimate the equilibrium curvature that the BHA can achieve at specific operational parameters. Bit-steerability and bit-walk angle are used as calibration variables within the model to account for the bit/formation interface, which prevents the need for specific bit or formation details for accurate modeling. Validation of the new directional estimation method is performed via comparisons to an established nonlinear finite element model (FEM) as well as actual directional performance data from both rotary-steerable systems (RSS) and steerable mud motors.

The resulting modeling algorithm shows a drastic improvement in the calculation time of directional sensitivity analysis, obtaining results in 1-10 seconds for even larger more complicated BHAs, compared to 1-15 minutes using nonlinear finite elements. This comparison also shows a strong agreement between the calculated values of the two modeling methods, establishing confidence that the new approach adequately accounts for the various intricacies and nonlinearities that exist downhole. The reliability of the new directional model is further highlighted via a direct comparison with actual directional performance data.

The use of this new efficient drillstring-wellbore contact model, in combination with a direct integration of drillstring deflections, provides an efficient alternative to calculating the directional behavior of BHAs in realistic wellbores. The developed algorithm shows a significant improvement in calculation time compared to traditional nonlinear finite element approaches, while maintaining accuracy for complex scenarios. This method lays the foundation for real-time drilling optimization, and integration into automated drilling guidance systems.
Evaluating the Performance of a Cost-Effective Creep Testing Setup on Bismuth-Tin Alloy Specimens: Challenges and Future Directions
Authors: Hmadeh Lewaa , Essén Tora , Elahifar Behzad , Sangesland Sigbjørn
Published: February 2025

Well plugging and abandonment operations are critical in the oil and gas industry, especially when it comes to regulatory compliance and environmental safety. A key factor in this operation is the quality of the sealant used to close boreholes and prevent hydrocarbon migration. Bismuth alloys have emerged as a promising sealing material due to their distinctive properties. In the framework of P&A, investigating the creep behavior of the metal plug is essential to assess its sealing performance and long term integrity.

Creep, by definition, is a time-dependent deformation occurring when metals are subjected to a constant load at high temperatures over an extended period. Typically, creep testing machines evaluate how a material performs under these conditions. However, due to the unavailability of such machines and the necessity to test the creep properties of a bismuth-tin metal alloy, a low-cost creep testing setup was developed. This paper aims to investigate the creep properties of the bismuth-tin metal alloy at various temperatures (40, 60, 90, and 120°C) using the setup developed. The setup includes a steel chamber heated by an oven exhaust and a loading device attached to a support structure linked to the chamber. Inside the chamber, a bismuth-tin specimen is installed, and weights are applied to induce the load. A thermometer and a length gauge monitor the temperature inside the chamber and record the change in length, respectively. The maximum load applied to the specimen can be 24 kg.

Creep curves plotting strain versus time for the bismuth-tin alloy, under a constant load, were generated at different temperatures. Preliminary results indicate that creep effects become more pronounced at higher temperatures, where the cross-section of the tested specimen thins and ruptures more quickly. Although these results are not fully accurate, the study aims to evaluate the feasibility of this setup as a cost-effective alternative to expensive creep testing machines.

This work is part of an extensive in-house research that contributes to the understanding of how this unique material behaves under downhole conditions, thus leading to better P&A practices in terms of enhanced safety and operational efficiency, reduced leakage risks, and minimized costs. The ultimate goal of this technology is to be qualified for widespread usage as a barrier element in P&A operations, meeting the requirements of the NORSOK D-010 standard.
Impact of Change Implementation in the Driller's Control Cabin: A Human Factors Assessment with Design Implications
Authors: Arndt E. , Hoffart I. , Gabrielsen S. H.
Published: February 2025

Technological inventions and new ways of working transform the driller's control cabin into a place of change. Focusing on the human and the overall system is necessary to ensure proper implementation of changes. Research indicates that too little attention has been given to human factors and user-centric design in drilling operations in the past. Through identifying existing pain points, new design concepts for driller's control cabins have been developed. Interviews and rig visits were conducted for the assessment of the current situation, comprising questions about the human-machine interface, layout, work environment and workload. The main findings in the driller's cabin were information overload and screen clutter, inadequate workplace ergonomics and work environment, and distractions from core tasks for the driller. As an underlying reason, a lack of a holistic, human-oriented approach during the implementation of changes was observed. Based on these findings three complementary design concepts were developed. The first concept, a unified digital workspace, is defined through shared screens and/or data from several digital systems and shows operation-sensitive data in a consistent way. The second concept, a dynamic physical workspace, entails an ergonomically well-designed workstation regarding hardware, equipment and layout. The third concept, a cabin built for change, ensures that the cabin is fit for the future by remaining relevant and functional through ongoing technological advancements and evolving work practices. Every design concept can increase performance, safety and wellbeing, but technical and financial challenges must be met for the realization of each concept. If the current situation remains, the conditions in the driller's cabin will only deteriorate further in the future with potential consequences such as increased work-related illness, higher potential for operator error, and reduced operational performance.
A Comprehensive Statistical Analysis of Standard Tortuosity Computations in Unconventional Laterals
Authors: Lesso Bill , Rodriguez Edgar
Published: February 2025

Directional drilling tortuosity in unconventional laterals is accepted as a quality indicator. There is some agreement on the computation but none on any of the statistical characteristics of this tortuosity. This study presents a comprehensive analysis of tortuosity computed on a universe of 160,000 laterals drilled since 2010, aiming to establish statistical benchmarks and quality metrics for drilling and completion optimization.

The two most widely used tortuosity calculations — Large Scale Tortuosity (LST) and the University of Texas Tortuosity Index (UT-TI)—are applied to survey data from wells across Louisiana, New Mexico, Texas, and the four states in Appalachia, with publicly available data spanning from 2010 onward. Scripts were designed to calculate tortuosity in the lateral sections of the 115,700 verified wells drilled in these areas. The methodology for determining the start of the laterals, error checking of the survey data, and tortuosity calculation is outlined.

Statistically lateral tortuosity conforms to a log-normal distribution with a mean and standard deviation. The median tortuosity of all the wells is 1.505 deg/100ft. Rotary steerable systems (RSS) are gradually replacing positive displacement motors (PDM) in the time frame of this study. Laterals drilled with RSS's exhibit approximately half the tortuosity of those drilled with PDM's. This transformation is seen in the yearly distributions of lateral tortuosity. The findings offer insights into regional drilling practices, such as the prevalence of RSS use in Appalachia, and highlight the ability to track industry-wide transitions from PDM to RSS over time. The proposed metrics provide a valuable tool for improving wellbore quality and optimizing both drilling and completion designs.
Integration of Three Digital Twins: A New Perspective on Wellbore Stability and Drilling Optimization
Authors: Kristiansen T. G. , Navabi J. , Ødegård S. I. , Hovda S. , Hallaråker M. H. , Speirs D. , Bere A. , Roberts D.
Published: February 2025

It can be difficult to explain wellbore instability events with current state-of-the-art wellbore stability workflows. Many times, one may observe toolmarks on the cavings at surface, indicating contact between wellbore wall and drillstring/BHA. This work integrates three state-of-the-art digital twins within the areas of drillstring dynamics, wellbore hydraulics/hole cleaning and near-wellbore rock mechanics. The ultimate goal is to better understand field observations. A well where one had no signs of wellbore instability when drilling the section but had severe problems with cavings and pack-offs on the trips out is investigated. The section had to be drilled multiple times. Many cavings had toolmarks on them. From offset wells and wellbore stability models, mud weight was acceptable. The analysis describes results for when each digital twin is run individually and when all three twins are coupled together. Each digital twin contributes with a variety of additional information when run individually: The hydraulic and hole cleaning model indicate that the wellbore should be relatively clean with the parameters used, provided that the hole is everywhere in gauge. The drillstring model indicated that the greatest lateral forces were present in the numerous stick slip events in the section. Downhole memory data and drillstring simulations show that the lateral shocks in these stick slip events could exceed 100 g. Moreover, transverse forces in the sticking periods, could be as high as 100 kN. The more advanced rock mechanics model indicates there is a mechanism in an interval with fractured shales in Lower Hordaland formation where the problems occurred on the trips out. Fluid invasion into fractures, cyclic ECD pressure and gravity is driving the deformation. We see that as fluid is invading the fractures and blocks are pushed into the hole and create a under gauge hole. This paper describes the multiplicative benefit of combining all these digital twins. The drillstring dynamic models describes the forces and shocks that are acting on the formations. The rock mechanical models can use these forces to demonstrate how the hole has been broken down, while the hydraulic and cutting transport models can explain the effect on hole cleaning when the hole is out of gauge. Together the set of digital twins, describes the field observations in a new and very holistic way. A possible consequence of this effort is that the next generation of practicing engineers will at all times have access to a set of digital twins that are continuously working to holistically explain all field observations. Such a system of digital twins will likely be an enabling ingredient for the next generation of planning tools and automation efforts.
Filter Disk Materials for High-Pressure/High-Temperature Filtration Testing: Characterization and Comparison with Natural Sandstones
Authors: Ivanishin I. B. , Lu J. , Klemin D. , He W.
Published: February 2025

Filtration and filter-cake building properties are fundamental characteristics for drilling and completion fluid. In high-pressure/high-temperature (HP/HT) filtration laboratory testing, ceramic disks are widely used as filter media to simulate the exposed sandstone formation. However, the properties of filter disks significantly differ from those of sedimentary rocks. The objective of the work presented in this paper is to characterize the commonly used filter disk materials, compare the materials with sandstone formations, and provide a basis for the optimization of drilling fluid filtration testing. The porosity and permeability of American Petroleum Institute (API) filter disk materials and outcrop sandstones were determined. X-ray microcomputed tomography (microCT) scanning provided a 3D image of the pore spaces. MicroCT scanning, combined with thin-section analysis, scanning electron microscopy (SEM) observation, and mercury injection capillary pressure (MICP), allowed for extracting the parameters of the pore network such as pore and pore throat size distributions. The measured properties of the filter disk materials significantly deviated from the manufacturer's data, i.e., permeability—up to 36 times. For example, the provided permeability for the tightest filter material, API 10, is 775 md, while the measured permeability is only 21.4 md. The porosity of the filter disk materials ranges from 39.3% to 45.4%, which is up to two to three times higher than that of natural sandstones. The tightest filter material, API 10, has a porosity of 39.3%, while sandstones with similar permeability could be less than 20% porous. With evidence from microCT and thin-section images, API 10 is composed of tightly distributed spheres with diameters from 80 to 120 μm. The interparticle pores account for 12% porosity, with pore sizes ranging from a few to 60 μm. The sample's measured porosity is higher than that estimated from microCT. This discrepancy suggests that the majority—the remaining almost 30%—of the pore space is created by the presence of smaller intraparticle pores within the spheres. The other filter materials mostly consist of angular grains, creating different pore connectivity and pore-size distributions. This paper presents the first detailed characterization of filter disk materials. Understanding the properties of the widely used filter disk materials provides a basis for proper disk selection to closely match the simulated formation rock and appropriate interpretation of HP/HT filtration testing results. The study also provides a basis for (1) optimization of the manufacturing processes of filter materials, or (2) substitution of ceramic filter materials with real sedimentary rocks for HP/HT filtration testing.
Integration of Novel MWD and Rig Data for Remote Operations
Authors: Bonderover Eitan , Godumagadda Anil , Yang Libo
Published: February 2025

A novel low-cost MWD provides data for integration with a new cloud-based rig data architecture. The new and advanced algorithms in the MWD system improve both data rate and reliability, making it a suitable source of data. The integrated data architecture combines an edge platform at the rig with a cloud-based system accessible through a unified interface. This enables the deployment of advanced algorithms for drilling automation and data analytics to improve operational performance. The edge platform also supports machine learning models to be trained in the cloud across regional rig data and deploy them to the edge, quickly and efficiently. A series of case studies are presented. One case study shows the reliability and performance of the new MWD system. A further case study shows the seamless integration of data from downhole and surface into a unified database.
Code Generation of Automatic Drilling Control System Functions with Embedded Verification and Validation Functionalities
Authors: Cayeux E. , Mihai R. , Herikstad R. V. , Olsen K. K. , Antosz K. , Pham M.
Published: February 2025

Over the past decade, the adoption of drilling process automation solutions has significantly enhanced drilling operation efficiency. This improvement has been achieved because Drilling Control System (DCS) providers have enabled external service companies to offer dynamic advice that can be used to parameterize Automatic Drilling Control System (ADCS) functions. However, developing externally managed ADCS functions poses challenges, particularly given the risk of potential failures due to spurious parameters. Therefore, it is essential to find a method to ensure that an ADCS function remains safe, regardless of the external inputs and measurements on which it depends. Typically, there are four types of ADCS functions: Fault Detection, Isolation, and Recovery (FDIR); Safe Operating Envelope (SOE); controllers; and automated procedures. The Drilling and Wells Interoperability Standards (D-WIS) sub-committee of the Drilling Systems Automation Technical Section (DSATS) has defined a general declarative data model that enables the description of ADCS function behavior. This data model allows external advisors to discover ADCS capabilities. Moreover, the same declarative description can be used to automatically generate code for ADCS functions, similar to how high-level programming languages are compiled into low-level microprocessor instructions. To support this, a low-level interface to the DCS has been defined. This interface is built to be resilient to unexpected communication failures, as it incorporates embedded Safe Mode Management (SMM), which transitions control from automated to manual mode in such situations. The interface is designed to handle potentially unacceptable values for each variable in its functions. Once the low-level interface to the DCS and the automatic code generator are certified, the only potential source of error lies within the logic of the ADCS function description itself. Given that this description is computer-interpretable, it is possible to execute automated test suites to verify the integrity of the ADCS function description. Additionally, it is feasible to mathematically verify certain properties of the ADCS function, such as whether it avoids infinite loops and reliably reaches an end state. Statistical information about path coverage in the finite state automaton graph underlying the data model can also be extracted. By using the ADCS declarative description as the sole information source for generating ADCS functions, the descriptions remain synchronized with their implementations. The industry-led initiative to enable interoperability between drilling computer systems at rig sites has a transformative impact, unlocking new possibilities such as the automatic generation of ADCS functions—capabilities that would be inconceivable without a comprehensive framework like the one established by D-WIS.
Impacts On Tare Quality and Best Practices from Fleet-Wide Breakover Detection Algorithm
Authors: Groh A. , Kaya M. E. , Dunbar D.
Published: February 2025

Previous work from this contractor highlighted development of a system to detect drillstring breakover through application of Hidden Markov Models to real-time data. The system offered to improve weight-on-bit (WOB) and differential pressure (DP) measurements through more accurate taring, as well as general torque and drag (T&D) monitoring and connection optimization. Fleet-wide deployment of this system has offered several routes for optimization and key learnings that have improved taring quality and general understanding of drillstring behaviors. This work will highlight some of these findings and provide recommendations for when and how to tare in the weight-to-slips portion of a drilling connection.

This contractor first developed the system in late 2022 and has since deployed it to all onshore drilling rigs in its fleet, with controls-level integration on several rigs in late 2023. These deployments were performed by utilizing on-location compute to detect and measure breakover events for every motion performed. Throughout deployment several cases were studied in detail that offered significant learning and improvements on best practices. Additionally, a fleet-wide analysis of over 70,000 drilling connections was performed to understand large scale behavior of the generated tare references and the behavior of drag.

While taring, the system was critical for ensuring accuracy. Traditional tares performed while tagging bottom in lateral sections, and even some deep intermediate sections, were found to be inadequate and generated significant error due to high drag or delays in pump pressure stabilization. Throughout these processes several interesting phenomena have been observed, including sudden, large changes in static hook load between stands, as well as speed-dependent drag that must be considered for accurate tares. The system also generates measurements of physical properties of the system, like drillstring axial stiffness. These estimates were found to align nicely to their theoretical values in many instances, validating the approach and measurement scheme. The above has culminated in this contractor's data-driven recommendations for taring prior to drilling connections and is of interest to members of the drilling community for protecting downhole tools and optimizing drilling performance.
Drill Pipe Damage Tracking and Analysis System to Reduce Drillstring Failure
Authors: Zhang Yifan , Cao Dingzhou , Moos Sheldon , Vora Kumar , Ashok Pradeepkumar , Chen Dongmei , van Oort Eric
Published: February 2025

Drill pipe (DP) damages, caused by excessive loads and suboptimal drilling operations, can lead to undesired drilling dysfunctions, extra non-productive time, and increasing pipe repair expenses. Identifying the root causes of DP damages and their correlation to the drilling programs can help optimize the well/drillstring design as well as the drilling operation and ultimately reduce the risk of severe drillstring failure. In this study, over 300 DP inspection reports (over 170,000 joints of 5" and 5.5" DPs) and drilling data from over 1,000 wells are investigated to summarize the average connection damage rates and DP thickness loss. Damage decomposition among thread, seal, hardband, reface, damage beyond repair (DBR), and thickness loss are concluded for different pipe sizes, formations, and contractors. Furthermore, operation envelope, mud type, vertical/lateral footage, lithology, drillstring structure, and other well designs are selected as essential features for the damage-operation correlation analysis. Cases of severely damaged strings are investigated as well. Based on the analysis results, a comprehensive understanding of DP damage rates and mechanisms has been achieved to practically optimize drilling jobs, reduce drillstring failure risks, and cut drilling expenses. A DP analysis automation pipeline is also built to make the analysis results evergreen.
From Bit-Rock Interaction to BHA Vibration: Experimental and Numerical Perspectives
Authors: Mahjoub M. , Nguyen K.-L. , Dao N.-H. , Menand S. , Endres L. , Cheng C. , Mada H. , Feng X. , Sun J.
Published: February 2025

Studies indicate that the interaction between the drill bit and rock formations induces vibrations along the bottom hole assembly (BHA). Parameters such as weight on bit (WOB) and rotation speed affect the engagement of the cutters in the rock, otherwise known as depth of cut (DOC). DOC is crucial for bit stability; a poor BHA design combined with a suboptimal choice of DOC can lead to axial, torsional, and lateral instabilities (bit bounce, stick-slip, and bit whirling phenomena). Optimizing the bit design to address these vibrations is vital for improved drilling performance. Both experimental studies in the lab and numerical simulations are essential tools to test and improve bit design before real-world drilling.

In this work, a transient bit-rock interaction model is implemented to study the evolution of cutting and friction forces on each individual cutter, whether it is a cylindrical or shaped cutter. Specific models are introduced based on laboratory scratch tests, where the performance of each shaped cutter type is related to its main geometrical characteristics. These elementary forces are combined to provide the overall response of the bit. It accounts for axial, torsional, and lateral motions of the bit as well as the possible transition between different rock layers that generally trigger bit instability. This model is coupled with a time-domain dynamics model of the drill string to examine the implications of the cutting process on the BHA vibration. Experimental lab data on a drill bit are used as a basis to calibrate the model. The experimental measurements are then complemented with the simulation results to have an in-depth understanding of the bit behavior.

Comparisons of lab and simulation results showed a good agreement for WOB, torque on bit (TOB), and lateral acceleration. Based on these results, the numerical simulations allowed investigation of the cutter elementary forces, ranking them in terms of work rate and durability. Moreover, the simulations showed how bit whirl can propagate upwards in the string, creating lateral vibrations in the rotating shaft. With the collected information on the bit behavior, an application is carried out on a realistic BHA and wellbore trajectory, and the vibration levels are analyzed along the whole BHA.

This scope of work has many implementations, testing different combinations of drill bits, rock formations, and drill string assemblies. It can be used either as a pre-analysis tool to optimize the bit and BHA designs, or as a post-analysis tool to understand a specific vibration event and prevent recurrence. The addition of new elementary cutting models for different shaped cutters provides other axes of bit design improvements, where the type, number, and placement of the shaped cutters can be investigated.
Corrosion Fatigue Analysis for Tubular Design in Geomechanical Energy-Storage Wells
Authors: Liu Zhengchun , Samuel Robello
Published: February 2025

Recently, geomechanical pumped storage (GPS) emerged as a new approach for storing electric energy from solar or wind power. To charge, water is pumped down the well into high-pressure reservoir. To discharge, high-pressure water flows up to drive a turbine. The cyclic operations in a GPS well cause changes in temperature and pressure of the wellbore, which may lead to fatigue failure. This paper presents an integrated solution of fatigue analysis for GPS well integrity. The varying casing temperatures and temperature-dependent casing loads were obtained through numerical simulations of cyclic operations such as water injection, shut-in, and water production. All these simulations were accomplished using commercial software, including a thermal flow simulator and stress analyzer. The previously simulated casing loads were then used to calculate localized stress amplitude, strain amplitude, and mean stress. Finally, the localized strain and stress values were used as input parameters of a corrosion fatigue model to estimate the lifetime (cycles) of each tubing or casing section. The corrosion fatigue model was implemented in a computer program and integrated with the thermal flow and stress analysis commercial software. A field case of a GPS well was studied with the integrated thermal fatigue simulation. The tubing/casing failure locations were analyzed and explained in terms of environmental conditions and cyclic stress/strain conditions. The field case study indicates that the traditional stress or strain-based fatigue analysis might not be adequate to assure wellbore tubular integrity. In the aqueous environment, corrosion fatigue is necessary for certain carbon steels and alloy steels. When integrated with numerical thermal flow simulation and multi-string stress analysis, the corrosion fatigue model provides a more accurate fatigue life estimation of casing and tubing in GPS wells. Corrosion fatigue model was coupled with wellbore thermal flow analysis, helping to proactively prevent tubing/casing fatigue failure during the cyclic operations in GPS wells and other similar scenarios. It provides an important design rationale for total well integrity.
Rethinking CO2 Injection Wells for Next-Generation Offshore Carbon Storage
Authors: Hassan A. , Jaculli M. A. , Schei H. , Stanko M. , Sangesland S.
Published: February 2025

Carbon Capture and Storage (CCS) is critical for meeting global climate goals, yet its large-scale deployment faces significant economic and operational challenges. This study introduces lean CO2 injection well designs to address scalability issues, emphasizing cost efficiency and well integrity. By leveraging design innovations such as mechanical Downhole Safety Valves (DHSVs) and simplified casing configurations, the proposed concepts achieve up to 25% cost savings compared to traditional designs. These improvements are tailored to meet regulatory requirements while enabling large-scale implementation.

The research evaluates three novel well concepts, analyzing material and operational cost reductions alongside well integrity consid- erations. The study highlights the limitations of conventional two-barrier philosophies for CCS and presents strategies to align innovative designs with existing frameworks. By integrating cost-effective and scalable solutions, this work provides a pathway for advancing CCS technologies and achieving storage targets of 1 Gt annually by 2030.
Well Repurpose Potential for Geothermal Heat: Comprehensive Assessment Tool Integrating Economic and Environmental Aspects to Facilitate Educated Investment Decisions
Authors: Mozas J. M. , Zikovic V. , Reinicke A.
Published: February 2025

In the Netherlands and across Europe, many oil and gas wells are scheduled for plugging and abandonment due to uneconomical conditions. The potential for repurposing these wells for geothermal heat production or energy storage is often overlooked due to conversion costs, liability transfers, marginal economics, and well integrity challenges. However, well repurposing is increasingly recognized as a strategic research priority in Europe, supported by several past and ongoing projects. To address the lack of publicly available methodologies, we propose a structured approach for screening wells and guiding users in the selection process. This methodology is based on reservoir, well, and surface requirements, with future integration of heat networks to complete the ranking options. The workflows help identify promising candidates and their specific repurposing potential. Once options are identified, an economic assessment, including a life-cycle analysis, is performed to determine the net present value (NPV), levelized cost of heat (LCoH), and specific CO2 footprint of each repurposing option. A comparison with the costs and energy output of constructing a new well is then conducted to identify the most advantageous solution. This paper presents a standardized workflow to assess the repurposing potential of wells, both in generic terms and as applied to Dutch wells using publicly available data.
Effect of Modularity on the Thermal Management of Optimized Printed Circuit Boards for Geothermal Drilling Tools
Authors: Plata G. , Singh S. , Clegg J.
Published: February 2025

This paper investigates a novel approach to thermal management in high-temperature Measurement While Drilling (MWD) tools, addressing critical challenges in geothermal drilling where conventional systems fail to operate efficiently above 175-185 °C. The proposed design integrates modular mechanical housing and advanced thermal management systems optimized for circular, axially stacked Printed Circuit Boards (PCBs).

Using Aluminum Nitride (AlN) ceramic PCBs for their superior thermal conductivity, the design enables radial heat dissipation, reducing thermal resistance and maintaining operational stability under extreme conditions.

Results indicate that the modular design ensures effective heat evacuation through metal-to-metal contacts and optimized chassis geometry. At a nominal chip power of 0.5 W, the maximum temperature increase remained below 3.5 °C for four PCB stacks and 210 °C mud temperature, highlighting the system's reliability. The findings underscore the importance of modularity for simplifying assembly and improving thermal management in harsh environments.
Predicting Drill Bit Remaining Useful Life and Identifying Drilling Disfunctions by Physics-Based Inversion and Data-Driven Model - Case Study of Utah Geothermal Wells
Authors: Lee H. , Mitkus A. , Ziehm T. , Gee T. , Reynerson P. , MCcarthy K. , Gupta P. , Agarwal N. , Willerth M. , Pare A.
Published: February 2025

Drilling through hot rocks in geothermal wells often leads to multiple unplanned trips due to issues such as drilling dysfunctions, thermal degradation of cutters, inadequate hole cleaning, tool failure, and lost circulation. Accurately predicting bit conditions in real-time can help avoid poor decisions, such as continuing to drill with a damaged bit or pulling the bit out too early. This paper focuses on developing a hybrid model that combines physics-based inversion with data-driven techniques to accurately estimate the remaining useful life (RUL) of drill bits and detect drilling dysfunctions in geothermal wells in Utah.

This approach combines inversion models for depth relaxation with machine learning algorithms to predict the drilling performance of each bit run in geothermal drilling operations. Data on drilling dynamics, total flow area (TFA), and bit dull grade were collected from 63 PDC bit runs in the lateral sections of 15 geothermal wells with an 8.75-inch hole size. The collected data was used in physics-based inversion to calculate relaxation depth, while the machine learning model identified patterns related to bit wear, drilling anomalies, and dysfunctions. Historical data and real-time drilling parameters were utilized to train and validate the model.

The hybrid model showed substantial improvements in predicting the RUL of drill bits and detecting drilling anomalies and dysfunctions. Specifically, it was observed that short run depths could result from fast relaxation depth, which is linked to inefficient drilling, anomalies, or dysfunctions. Additionally, the study found that increasing TFA could mitigate the thermal degradation of bit cutters. These factors—relaxation depth, run depth, and TFA—were used as inputs for a machine learning model to predict RUL and bit dull grades for each bit run. Furthermore, the physics-informed machine learning model can guide the selection of drilling set points when anomalies or dysfunctions occur, enabling timely resolution. The integration of physics-based and machine learning approaches yielded high prediction accuracy, reducing non-productive time and optimizing drilling performance. This method has the potential to be applied across various geothermal fields, providing a valuable tool for enhancing drilling efficiency and lowering operational costs.

This research presents a novel integration of physics-based and data-driven models for predicting drill bit RUL and identifying drilling dysfunctions. A key aspect is the exploration of the previously unexamined relationship between run depth and relaxation depth in the inverted domain. This analysis aims to enhance predictive accuracy and operational efficiency in geothermal drilling. The innovative approach marks a significant contribution to the advancement of drilling optimization techniques.
Slot Recovery Based on the 3D Dubins Curve Method
Authors: Liu Haoge , Aadnøy Bernt Sigve , Gjersvik Tor Berge , Kaarstad Eirik , Krossnes Bjørn Schmidt
Published: February 2025

This paper introduces the application of the 3D Dubins curve method for sidetrack trajectory design in slot recovery. With the constraints and the objective given, the method can quickly determine the optimal sidetrack kickoff point (KOP) location and generate the optimal sidetrack trajectory in just seconds. Robustness and efficiency of the method are demonstrated in the case studies with both synthetic data and real field data with various constraints such as location limits, angle limits and anticollision. The case studies also demonstrate how different constraints or objectives affect optimal sidetrack trajectory. Compared to the conventional sidetrack design process when complex constraints are involved, our method can be a game changer as it only cost seconds to investigate the objective subjected to the target and various constraints information.
Automated Correction of Drillstring Data for Improved Reliability and Trust in Use of Physics-Based Models in Drilling Advisory Systems
Authors: Yoon D. , Yi M. , Cortez J. , Behounek M. , Ashok P.
Published: February 2025

A major challenge in utilizing physics-based models such as torque and drag (T&D), hydraulics, cutting transport, drillstring dynamics, etc., in real-time, and with high reliability and confidence has been the lack of accuracy in drillstring data available as input to these models. This paper describes a methodology to automatically cleanse drillstring data, ensuring that the model outputs are accurate and trustworthy.

The data cleansing process involves comparing measured data with model predictions and iteratively resolving the anomalies. First, the unit weights and lengths of the bottom hole assembly (BHA) components are adjusted by minimizing a specially defined loss between the measured and predicted hook load from a T&D model. Subsequently, the outer diameter (OD) and inner diameter (ID) of the components are corrected by minimizing the discrepancy between the observed standpipe pressure and the modeled pump pressure using a hydraulics model. In addition, the method leverages a comprehensive database of manufacturer drillstring specifications to ensure that the corrected values are realistic.

The proposed approach was rigorously validated using field data, demonstrating its effectiveness across various BHA combinations and wellbore conditions. Additionally, by using a comprehensive drillstring specifications database, the process achieved greater robustness, particularly improving corrections in scenarios where field data was limited. After data cleansing, both the T&D and hydraulics models showed significant improvements in accuracy. The T&D model aligned more closely with field data, resulting in more accurate friction factor and downhole weight on bit (WOB) estimations. Furthermore, the hydraulics model provided better pressure estimates along the drill string, enhancing the safety of well construction. Other models, such as hole cleaning and drillstring dynamics, also stand to benefit significantly, leading to better downhole situational awareness and more reliable drilling operations.

This paper is the first to describe an automated drillstring data cleansing method that enhances the quality of critical input parameters for various drilling-related models. The proposed approach seamlessly integrates information from multiple models, real-time data, and a comprehensive database to ensure precise and consistent correction of drillstring specifications. This approach promises to significantly increase the use of physics-based models in real-time advisory and automation systems.
Estimating Hole Cleaning Efficiency in Real-Time by Combining Along String Measurements and Hydraulic Modelling
Authors: Tamaddon S. , Gjerstad K.
Published: February 2025

Drilling operations require the continuous removal of drill cuttings to the surface through the drilling mud. Any accumulation of cuttings—such as beds in horizontal sections, avalanches in inclined sections, or sagging in vertical sections—must be promptly addressed to prevent severe complications. Without real-time insight into hole-cleaning conditions, these issues can escalate, causing delays, increasing costs, or even necessitating the abandonment and costly restart of the well. An Along String Measurement (ASM) system, combined with wired drill pipe technology, provides high-frequency measurements of multiple physical properties at various depths. This capability far exceeds the transmission rates of traditional mud pulse telemetry, offering new opportunities to gain real-time insights into hole-cleaning conditions.

This research focuses on identifying the real-time presence of drill cuttings in the mud by leveraging ASM readings, primarily downhole pressure, with optional inclusion of temperature data. A new cuttings estimation module has been developed and integrated into an existing system for drilling optimization and control. Currently, this module is being tested using historical drilling data from real wells.

The process starts by identifying periods when the well contains clean drilling fluid (i.e., free of cuttings) prior to drilling a new section. By analysing pressure differentials between adjacent sensors and leveraging known densities of clean mud and cuttings, the system calculates the cuttings fraction across different wellbore zones. This approach was validated by comparing its results to those of a physics-based model that has been extensively tested and proven reliable through years of operation as a real-time digital twin during drilling activities. The findings confirm the system’s ability to determine the proportion of drill cuttings in each zone by acceptable accuracy.

The paper presents the underlying concept of this methodology, offering a detailed overview of wellbore hydraulics and how these principles are applied to cuttings transport estimation. A sensitivity analysis highlights the robustness of the approach, demonstrating its resilience to typical uncertainties in parameters such as temperature, mud composition, and measurement data. Notably, the system is highly flexible, capable of functioning either as a standalone solution for estimating cuttings transport or as a complementary tool to existing physics-based models. By leveraging the strengths of both approaches, it delivers enhanced accuracy and optimal predictions for drilling operations.