bluuebunny/crossref_metadata_2025_split huggingface dataset:
MODELING OF INFRARED RADIATION PROPAGATION THROUGH THERMAL INSULATION SURFACES
Authors: Levchenko Larysa , Bolibrukh Borys , Kovalenko Oleksandr , Myshchenko Iryna , Asieieva Liudmyla 
Published: February 2025

The development of materials for blocking infrared radiation, provided there are several layers with different thermophysical characteristics, requires large amounts of experimental research. Therefore, it is advisable to automate this process. This is possible due to the modeling of heat flow through the layered material. The purpose of the research is a modeling of the passage heat flow through a material made of layers different thermophysical properties and verification of the modeling results. Results of the research: Modeling of the passing heat flow through a layered structure with different thermophysical properties of individual layers was carried out. An air gap of small thickness was assumed between the layers of materials. Changes in the temperature of the outer layer were determined depending on the time of heat passing through the layered structure. The obtained dependences of temperature changes of each layer in time and space. The obtained easy-to-use graphical dependencies are suitable for the designing a protective material with the required properties. The temperature gradient between the heat source and the outside space was taken into account. The modeling results were verified using a calibrated infrared radiation detector. It was established that the application of modeling allows to choose the thermophysical characteristics of individual layers the material, which ensure the temperature of the outer layer and is equated to the temperature of the environment. A comparison of the manufactured material with known analogues showed that it has better protective properties with a smaller thickness. Conclusions: The application of the modeling heat flow propagation through a layered structure with different thermophysical properties of individual layers allows designing protective materials depending on operating conditions.
Optimization of Information Flows Based on Network Models of Systems
Authors: Konopacki D. A. , Lobaty A. A. 
Published: February 2025

The educational process is a complex social management system, the elements of which are combined and interact through information flows. At the same time, information flows can differ in purpose and type of transmitted information. The article is devoted to the substantiation of the need and ways to optimize information flows existing in the educational process. An analysis of the tasks that exist in organizing the educational process is provided using the example of a higher educational institution, the role of modern information technologies that ensure student learning. The educational process is a complex social management system, the elements of which are combined and interact through information flows. At the same time, information flows can differ in purpose and type of transmitted information. The article is devoted to the substantiation of the need and ways to optimize information flows existing in the educational process. An analysis of the tasks that exist in organizing the educational process is provided using the example of a higher educational institution, the role of modern information technologies that ensure student learning. This analysis is also typical not only for higher education institutions, but also for institutions of additional education for adults, during training in which students simultaneously work, are busy with family and study mainly remotely. Representation of the educational process using network models allows them to be formalized, presented in a form convenient for optimization, depending on the task, corresponding to the objective function and specified constraints that take into account the specifics of each information model of the educational process. Network models of organizing the educational process, their features and formalization - presentation in a form convenient for modeling and optimization are considered. An analysis of various types of information used in the educational process, methods for its quantitative assessment are carried out. On the basis of the models, the problems that exist in the optimization of information flows and ways of their solution based on the application of mathematical methods of optimization are substantiated. The connection of the problems pertaining to optimization of information flows of the educational process with similar problems of the application of information technologies in various systems of management in social and economic areas is shown
Hydro-Mechanical Behavior of a Granite-Based Geopolymer Sealant Exposed to MgCl2-Brine: Implications for CO2 Geosequestration
Authors: Hajiabadi Seyed Hasan , Khalifeh Mahmoud , van Noort Reinier 
Published: February 2025

Abstract
The stability of geopolymers (GPs) as alternatives to Portland cement for CO2 geosequestration is critically dependent on their performance under brine exposure typical of downhole conditions. This study investigates the hydro-mechanical behavior of a granite-based GP system subjected to brines of different MgCl2 concentrations (0-15 wt.%). The use of MgCl2 brines as opposed to the more commonly studied NaCl solutions addresses the often-overlooked impact of Mg2+ ions. Employing an imposed flow technique, GP samples were subjected to MgCl2 brines at 90°C and a confining pressure of 13.8 MPa. Subsequent analyses included mechanical property testing and microstructural evaluations. The results demonstrated a salinity-dependent reduction in GP permeability, ranging from 28% to 79% as MgCl2 concentration increased. Mechanical tests revealed that higher salinity enhanced compressive strength and Young’s modulus, while reducing Poisson’s ratio. These alterations suggest enhanced material rigidity, but also indicate a heightened risk of mechanical failure under strain. Additionally, although the ratio of compressive strength to Young’s modulus (CS/E) decreased relative to the reference sample, it remained consistent across varying MgCl2 concentrations. Microstructural analysis identified robust calcium-aluminosilicate-hydrate (C-A-S-H) gels and zeolites formed in the presence of brine, contributing to the GP’s resistance to deformation and potential cracking. Furthermore, Mg2+ ions facilitated the formation of hydrotalcite, improving the GP’s Cl- ion adsorption capacity and potentially reducing the risk of chloride-induced corrosion in steel. These findings offer new insights into the performance of granite-based GPs for CO2 geosequestration and underscore the significance of material composition and environmental conditions in optimizing the durability of sealants.
Long-Term Evaluation of the Thermal Conductivity of Class H and G Cement Under Various Additives, Temperatures, and Curing Conditions
Authors: Abid Khizar , Velásquez Andrés Felipe Baena , Teodoriu Catalin 
Published: February 2025

Abstract
The thermal conductivity (TC) of the cement is one of the important parameters used in different simulations and numerical models to find or predict the integrity of the well cement, especially if the old oil and gas wells have to be retrofitted for geothermal or Carbon Capture and Sequestration (CCS) projects. Hence, it is important to use the true value of cement thermal conductivity, which can only be achieved after long-term testing.
The control samples used in this study consisted of Class G and H cement, as it is the most common cement used in the petroleum industry. The additives incorporated in the neat sample consisted of 5% Gilsonite and Bentonite. The samples were cured for 486 days and were placed in two different conditions, i.e., dry and wet. Moreover, the effect of temperature on the TC value was performed on the Class G cement, with one set of samples exposed to a 75°C (60°C for 1.5 months) water bath and the other placed in ambient conditions for almost 1 year. The testing of TC was measured throughout the curing period with the help of Thermtest Portable Measurement Platform −2.
Our findings suggest that the addition of the additive to the control samples significantly influences the TC of the samples. The value of TC for dry or wet cured samples continues to evolve with the curing period and becomes consistent after certain curing periods. However, wet-cured Class G and H incorporating 5% Gilsonite kept on fluctuating till 300 days of curing and became relatively constant after that. Whereas, the TC value of neat samples became consistent after 28 days of curing. Samples that were exposed to 75°C showed lower thermal conductivity as compared to the sample exposed to the ambient condition. Moreover, an increase in the TC value was noticed when the samples were switched from 75°C to 60°C for 1.5 months and then decreased again when brought back to 75°C. This trend emphasizes the effect of temperature differential on the thermal conductivity of the cement samples. It was also noted that irrespective of the curing condition, the highest values of TC at 486 days of curing were from Class G and H. Whereas the lowest in the wet and dry cured samples were from Class H+5% GS, and Class H+5% Bentonite, respectively.
This paper presents, for the first time, the long-term thermal conductivity of a sample cured under different temperatures, additives, and curing conditions for more than 450 days. Hence, the information from this study can be crucial in determining the optimal curing period for different cement types in various conditions from which the consistent value of thermal conductivity can be obtained.
Next Level Instrumentation in PDC Bits: Measuring Temperature at Every Cutter While Drilling
Authors: Panayirci H. M. , Robinson A. 
Published: February 2025

Abstract
This paper presents a unique experimental study, where every cutter on a modular PDC bit is instrumented to measure the temperatures while drilling. This level of instrumentation is enabled thanks to the recent miniaturization in electronics and advancements in additive manufacturing techniques. A modular bit concept is introduced to utilize these capabilities, where instrumented blades are designed to house all the electronics and sensors necessary to instrument the cutters. Cutter temperatures are measured while drilling and the recorded data are presented. It is shown that the cutter temperatures react to the drilling parameters and therefore can be used to assess the drilling performance. Furthermore, the data acquired in the experiment presents a unique opportunity to calibrate and further improve existing numerical models.
Sealing and Durability Evaluation of Microannulus Treatment with a Resin-Based Material: Permeability and Tracer Measurements in a Full-Scale Test Section
Authors: Jimenez K. Beltran , Kragset S. , Skadsem H. J. , Lima V. N. , Stormont J. C. , Taha M. Reda 
Published: February 2025

Abstract
Annular cement can be compromised due to suboptimal placement or operational and environmental loads during the lifetime of the well. This can result in sustained casing pressure, and several sealing materials are offered as solutions to repair the faulty cement. This paper presents a review of current treatment solutions and a novel experimental methodology for testing the effectiveness of materials injected into a full-scale diameter test section with a debonded inner casing. A test cell was constructed consisting of two concentric sections of 9 5/8-in and 7-in casings, respectively, with conventional class G well cement in the annular space. Controlled pressure manipulation was utilized to debond the inner casing from the annulus cement sheath and form a leakage path with gap-width less than 100 micrometer. The initial condition of the annulus before treatment was determined by gas and water permeability measurements along with tracer measurements. Subsequently, treatment material was injected into the annulus and cured for two days. Finally, gas and water permeability were measured to evaluate the treatment's effectiveness. The measurements were periodically repeated while pressure cycling to assess the material's durability. The methodology shows the potential to test different chemical treatment materials and compare the outcomes. The first test conducted and presented in this paper showed the results of injecting a nano-modified polymer sealant. Findings indicated that after the first injection, a drastic reduction in leakage rate for both water and gas of 97% was achieved. Tracer measurements revealed that the arrival of tracer at the outlet of the cell was substantially delayed by the treatment, in qualitative agreement with the reduction in leakage rate. To evaluate the durability of the treatment, the cell was submitted to cyclic loading of casing pressure with periodic permeability measurements. The leakage rate did not substantially increase after 80 cycles of radial casing expansion, but radial fractures in the cement may have been induced. This work presents a new experimental methodology that allows quantitative performance evaluation of new treatment technologies in full-scale test sections following the recommendation given by the UK Guidelines for material qualification (issue 2).
Assessing the Absolute and Relative Accuracy of Magnetic Variometers Compared to Observatory Data for IFR2
Authors: Beggan C. D. , Clarke E. , Knight P. , Lawrence E. , Marr T. , Martyn T. , Turbitt C. , Wang G. , Williamson J. 
Published: February 2025

Abstract
The Earth's magnetic field changes constantly on short timescales (minutes to days) due to the Sun's influence on the magnetosphere and ionosphere and on longer timescales (months to decades) due to processes in the outer core. Accurately estimating the static and changing fields at a drilling location, along with associated uncertainty, can be achieved with IFR2 using real time data from an absolute magnetic observatory.
In 2022, British Geological Survey installed three new magnetic variometer sites in the UK: in western Northern Ireland (FLO), central England (LEI) and on the south coast (HTX) to monitor space weather activity across Britain. These consist of a vector fluxgate magnetometer buried in the ground on a levelled plinth attached to a digitizer/logger and modem to transmit real time data. The systems are powered by a solar panel with batteries. The sites have been running for several years and offer a long-term experiment to determine the relative and absolute quality of the data when compared to the UK INTERMAGNET-standard observatories (LER, HAD and ESK). Using the IFR2 technique, we estimated the magnetic field values expected at each variometer site and compared it to the measured data.
We show results from the three variometers, outline the issues arising and compute uncertainties for each site. We find that, in general, while the variometer systems capture the short-period magnetic field variation well (which they are designed to do), action is needed to remove erroneous data such as spikes and man-made interference. However, we also find that even with great care taken to align the systems initially, the absolute accuracy is not well constrained due to temperature, instrument drift, subsidence and/or man-made disturbances. This pushes the uncertainties well beyond the ISCWSA-recommended limits of 0.1° in Dec, 0.05° in Magnetic Dip and 50 nT in Total Field.
Geopolymer-Based Hardening Spacer Fluid to Enhance Well Integrity
Authors: Khalili P. , Khalifeh M. , Delabroy L. 
Published: February 2025

Abstract
This study explores a specialized spacer fluid based on geopolymerization, designed to set and develop mechanical strength while maintaining a low slurry density. This innovative spacer can act as a supplementary barrier to cement, reducing the risk of sustained casing pressure and preventing fluid leakage. This work examines the spacer's mechanical properties at elevated temperatures to evaluate its potential for enhancing well-cementing operations and improving well integrity. Key properties, including rheology, density, and thickening time, are measured at 50°C bottomhole circulating temperature (BHCT) to assess the fluid-state properties of the spacer. Furthermore, its compatibility with Class G cement is assessed, focusing on the effects on rheological and mechanical characteristics. The effect of two different dosages of Na2CO3 in the spacer design as strength booster on mentioned properties is also examined. The results show that the spacer has a low slurry density (1.3–1.5 s.g.), enabling safe placement in weak formations. Its density can be increased by incorporating barite or granite to create a greater contrast with the drilling fluid. The spacer's thickening time offers a pumpability window of at least 7 hours at 50°C BHCT, aligning with typical cementing schedules. The compatibility results indicate that the hardening spacer is rheologically compatible, as evidenced by the measured R-index. When the cement was contaminated with 10% spacer, its compressive strength showed a 29% reduction after one day at 70°C BHST. While additional testing and refinement are necessary for the spacer to function as an independent barrier material, it shows potential as a complementary component to primary barriers like cement in its current stage of development.
Shaping the Future with PDC Cutter Technology, Progress, and Next Steps
Authors: Centala P. K. , Roberts T. S. 
Published: February 2025

Abstract
Recent improvements in Polycrystalline Diamond Compact (PDC) cutter technology manufacturing capability have led to denser, stronger diamond structures with much greater durability. The step change has made it possible to implement complex geometry PDC cutters on a much wider scale. This paper demonstrates the development of application-specific shape PDC cutters over the past decade, which provide greater drilling efficiency in various rock formations without sacrificing durability, benefiting the drilling industry. Over a 10-year period, a range of new complex geometry cutters that are more efficient and durable were developed and designed for greater drilling performance. Detailed research focused on improved rock failure mechanics. Analytical and experimental methods were used to optimize for greater impact strength to withstand breakage under high loading conditions. Pressurized single-cutter tests simulating downhole conditions were performed, measuring both axial and shearing forces on multiple new geometries with various rock types. Finally, these were complemented with full-scale drill bit tests prior to field testing in challenging applications globally. Single-cutter laboratory test results demonstrated that optimizing the diamond table geometry can improve performance with different rock formations. In many cases, lower forces and torque were measured while drilling, indicating greater drilling efficiency. In other examples, specifically enhanced geometry provided increased robustness. Under high loading conditions, the engineered geometry absorbed higher impacts without loss of structural integrity. The evaluation of five specific cutter geometries based on their drilling efficiency and durability illustrated that each provided individual benefits in certain rock types. Some were better suited for clastic carbonate-type formations, while others provided greater durability in harder interbedded limestones and conglomerates. A review of each of the five geometries will be presented, demonstrating their advantages. Standard round PDC cutters have dominated for almost 50 years, with thousands of bit iterations providing incremental advancements for the drilling industry. This research and development clearly show the benefits of novel PDC geometries and how they provide far greater drilling performance. The intricate process outlined is beneficial to the industry.
Optimized Surveys Enhance Trajectory Planning, Operation Efficiency and Minimize Shut-Ins
Authors: Zachman N. , Ledroz A. , Lowdon R. , ElGizawy M. , Rakhmangulov Rustam , Huitron F. 
Published: February 2025

Abstract
The advantages of combining survey data from different tools, such as MWD and gyros, have been quantified and demonstrated in previous publications, Chia et. al., Ledroz, et. al. However, the focus has been limited to individual wells. In this paper, we extend the scope of the analysis to a multi-well offshore platform to show the value of combining surveys to field development.
When envisioning the survey program for an offshore platform, much of the time and energy goes into the top-hole sections and how to safely kick off the wells in areas of magnetic interference and close proximity to multiple wells and casings. Once the kickoffs have been addressed, the survey and drilling plans for the deeper sections typically only involve an MWD tool and, depending on the cost and complexity, advanced survey corrections. The combination of surveys reduces the positional uncertainty by up to 30%, which allows more flexibility in the planned trajectories, larger allowable deviation from plan (ADP), and overall risk reduction.
A platform designed, with a nominal separation of 8 feet, was used for the analysis. The minimum kickoff depth was established at 1000 feet, with deeper kickoffs for wells drilled later in sequence. The results show that the reduction in wellbore positioning uncertainty allows for planning wells with lower torque and drag values and larger safety factors related to collision avoidance. The ability to combine surveys in real-time while drilling provides immediately actionable information to reduce deviation from plan and enhance risk management by ensuring the survey program is achievable. Additionally, due to the reduced risks, the number of shut-ins is minimized. Finally, if further wells are considered for the installation, including conductor sharing or open hole sidetracks, the new trajectories can be safely planned due to the increased space given by reduced positional uncertainty.
The use of combined surveys for uncertainty reduction has been limited to extended reach wells and specific challenging scenarios. The comprehensive use in every well of a platform is examined here, with all the implications for risk reduction and field development optimization.