bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seguridad y actividad de la Solución de Bardana como coadyuvante en el manejo del prúrito vulvovaginal en Colombia. Ensayo clínico fase II
Authors: Canaval Hoover , Bonilla Jairo , Scarpetta Claudia , Martínez Fernando , Orejarena Jaime , Solórzano Diana 
Published: February 2020

El prurito genital puede ser la manifestación de problemas alérgicos, infecciones genitales, entidades sistémicas o una reacción primaria. El manejo de este síndrome es un reto para ginecólogos y médicos generales.Objetivo: evaluar la seguridad y actividad de la solución de bardana al 1,2% en aplicaciones externas diarias por 5 días, como coadyuvante en el manejo de las vulvovaginitis para generar alivio del prurito.Metodología: el presente es un ensayo clínico de fase II, multicéntrico, abierto, no comparativo, realizado en pacientes con prurito genital, quienes fueron evaluadas en 14 ciudades colombianas. En el estudio se incluyeron a todas aquellas mujeres mayores de 18 años con prurito genital sin importar su etiología, quienes no hubiesen recibido tratamiento alguno para la vulvovaginitis o la vulvovaginosis en los 30 días previos a su inclusión en el estudio y quienes, además, no hubiesen utilizado ningún producto farmacéutico de manera tópica en los 8 días anteriores al inicio del tratamiento. Asimismo, se excluyeron todas las pacientes en estado de embarazo, con trastornos psíquicos o mentales de difícil control y con antecedentes de alergias a medicamentos. Se evaluó la edad de la paciente, la intensidad del prurito, la presencia de irritación vulvar, leucorrea, los agentes infecciosos asociados con ésta y la tolerancia.Resultados: se incluyeron 154 pacientes de las cuales se excluyeron 2 por no asistir al último control. Al final de los tratamientos, 83,6% de ellas manifestaban no tener prurito o sólo en una intensidad mínima y 11,8% lo referían como leve. El prurito clasificado inicialmente en 30,5% de las mujeres como severo se encontró sólo en 2,6% al segundo día y tan sólo en 1,3% persistía al final de la terapia. Similares resultados se obtuvieron en los subgrupos con infección demostrada por sólo cándida o sólo bacterias.Conclusión: la utilización local complementaria de una solución tópica de bardana en mujeres con prurito genital podría ser una alternativa eficaz de manejo.
Perbandingan Metode Regresi Spline Truncated dengan Regresi Linear Sederhana untuk Kasus Harga Saham Perusahaan Pertambangan di Indonesia
Authors: Widodo Edy , Irmayanti Adisti Nurul 
Published: February 2020

Saham merupakan surat berharga yang dapat dibeli dan dijual oleh perorangan atau badan usaha sebagai tanda penyertaan kepemilikan seseorang maupun badan usaha dalam suatu perusahaan atau perseroan. Salah satu saham yang mengalami dampak dari fenomena krisis ekonomi global adalah perusahaan pertambangan. Harga saham dipengaruhi oleh kurs rupiah. Data harga saham dan kurs rupiah masuk ke dalam kategori data longitudinal. Untuk menangani data longitudinal dibutuhkan analisis yang tepat, salah satunya dengan menggunakan pendekatan nonparametrik regresi spline truncated untuk mengetahui bagaimana pengaruh kurs rupiah terhadap harga saham. Model terbaik pada metode ini bergantung pada penentuan titik knot optimal, yaitu titik knot yang memiliki nilai GCV minimum. Model regresi spline truncated terbaik terletak pada orde 2 dengan 3 titik knot untuk PT Adaro Energy Tbk. dan PT Aneka Tambang Tbk., sedangkan untuk PT Indo Tambangraya Megah Tbk. berada pada orde 3 dengan 2 titik knot. Dengan pembanding nilai MAPE, hasil prediksi dengan menggunakan regresi spline truncated lebih baik daripada regresi linear sederhana Adapun nilai MAPE yang dihasilkan adalah 7,81% untuk PT Adaro Energy Tbk., 8,51% untuk PT Aneka Tambang Tbk., dan 12,74% untuk PT Indo Tambangraya Megah Tbk.
Tres personajes en busca del lugar perdido
Authors: Vera Chaparro Vanessa 
Published: February 2020

Los geniecillos dominicales (1964), Conversación en La Catedral (1969) y Los verdes años del billar (1986) son novelasprotagonizadas por jóvenes personajes, cuyas acciones se llevan a cabo en una sociedad peruana sometida porla dictadura militar. Ludo Totem, Santiago Zavala y Ricardo Yáñez experimentan una crisis individual como consecuenciade la ruptura que establecen con su lugar de origen (familia, clase social, círculos sociales). Nos interesaaquí determinar y analizar los factores de dicho distanciamiento y el efecto que ejerce sobre el proceso formativo deestos. Para ello, el esquema tripartito que propone Edward Said (2004): filiación, filiación problemática y afiliación, funcionarácomo el marco teórico de nuestro estudio. Con su ayuda, demostraremos que estos personajes son agentestrastocados por una violencia pública que se internaliza en los espacios privados que habitan para desfigurarlos e inclusodesaparecerlos.
Validation of Error Models – A Key Component of Risk Mitigation in Wellbore Collision Challenges
Authors: Ali Tarig , Ledroz Adrián , Weston John , Allen William 
Published: February 2020

Abstract
The estimation of wellbore position uncertainty, sometimes referred to as error modelling, is of vital importance when considering the safety and efficiency of the drilling process, particularly in crowded fields with tight spacing between wells. New survey tools employing new technology, new principles and sophisticated data processing techniques become available every year with different accuracy claims. The dependability of the error models and whether they properly represent the uncertainties of a given survey system, new or old, is not easy to judge. This paper describes a simple method to support the validation process of uncertainty models.
Multiple surveys of different type are often available for the same well with some degree of overlap for different wellbore sections. For example, the well might have been drilled using magnetic MWD data and later a drop gyro might have been run to reduce the positional uncertainty or to validate the magnetic data. Overlapping surveys can be compared, and the difference can be gauged against the claimed uncertainty models using the relative instrument performance model (RIP) test and the Chi-square test.
Analysis of several wells with different trajectories and more than 100 overlapping surveys has allowed a major oil company to build confidence and accept the uncertainty models claimed by one service company. This has allowed the oil company to implement the service company IPM (Instrument Performance Model) files without having necessarily to understand in great detail how the survey systems operate, how they are calibrated or quality controlled. Using the right models allows optimal planning of wells and survey programs, and reduces the risks of a collision while at the same time permitting wells to be drilled in congested fields.
The paper describes a simple approach for validating uncertainty models for survey tools. The tests used for the validation are available in most well planning software programs and can be completed by personnel without the necessary expertise required to understand the subtleties of all the survey tools involved in the process.
Downhole Attitude-Hold Controller Leads to Automatic Steering of Directional Wells with Improved Accuracy and Reduced Tortuosity
Authors: Zalluhoglu Umut , Tilley Jim , Zhang Wei , Grable Jeff 
Published: February 2020

Abstract
This paper illustrates the performance of a precise attitude-hold control feature enabled for a new-generation rotary steerable system (RSS) via an intelligent downhole navigation and control system. State-of-the-art downhole navigation sensors and a high-bandwidth pad actuation system are combined with advanced signal processing and control algorithms to ensure tight directional control of RSS along vertical, tangent, and lateral sections, maximizing the pay-zone contact for hydrocarbon extraction.
The intelligent downhole navigation and control system blends sensors measuring gravitational and magnetic fields surrounding the RSS to track the propagation of the borehole. The sensory measurements are conditioned by a set of advanced signal-processing techniques prior to being fed to the attitude-hold controller. The controller then generates a control signal to minimize both deviation from a reference trajectory and wellbore tortuosity.
Case histories from wells drilled using the automated attitude-hold control feature are presented. The field data include results from vertical, tangent, and lateral sections of wells in various formations from several conventional and unconventional applications. One case suggests significant reduction in generated doglegs upon engaging the attitude-hold controller in a lateral section with a challenging formation. Another case study shows that inclination was maintained within a tight error bound of ±0.1° during a tangent section. An example from a vertical well is also provided, where the vertical-hold control feature was able to hold inclination within 0.1° on average. The ability to tightly lock-in to a desired borehole attitude and to quickly adapt after altering the reference trajectory has proven that the attitude-hold control feature improves wellbore placement accuracy substantially, while minimizing tortuosity.
Simulating Drillstring Postbuckling State and Weight Transfer with Advanced Transient Dynamics Model
Authors: Chen Wei , Shen Yuelin , Chen Rongbing , Zhang Zhengxin , Rawlins Sheldon 
Published: February 2020

Abstract
As the drilling sections become deeper and longer, transferring more weight downhole to improve ROP is the primary concern to the operator. Drillstring buckling is a primary concern when using very aggressive drilling parameters. Buckling is a phenomenon where the drillstring suddenly loses stability as axial compression exceeds a certain threshold. The drillstring first buckles sinusoidally inside the wellbore which is then followed by helical buckling. Buckling leads to accelerated joint wear, tool fatigue failures, and lower drilling efficiency. To better manage the buckling risk, this paper proposes a method of simulating drillstring buckling inception and post-buckling state using an advanced transient dynamics model.
A buckling and post-buckling analysis methodology was developed based on the finite element transient dynamics model. The model captures the enriched physics involved in the buckling phenomenon: the large deformation of buckled drillstring, the strong non-linearity of contact and friction forces, and the dynamically triggered buckling due to drilling rotation. Transient dynamics simulations are conducted for drillstring with the actual well trajectory and rotation speed. Weight on bit (WOB) is ramped up gradually, and the drillstring deformation is monitored to detect the onset of buckling. The post-buckling state is examined to evaluate drilling efficiency and string reliability.
To conduct the model validation, an extended reach drilling (ERD) job was analyzed by the model. A measurement while drilling (MWD) tool was deployed in BHA to measure the downhole weight and torque. The simulation implies the helical buckling occurs in drill-pipe and captures the drilling weight and torque loss due to buckled string. Most existing buckling theories use the analytical equations of critical buckling load, which were normally derived based on the idealized assumptions, such as perfect wellbore shape and uniform tubular geometry, but neglect friction and string rotation. The proposed method simulates the drillstring buckling in the actual field drilling conditions. It gives more realistic predictions of buckling inception load and post-buckling configuration. The transient dynamics model is capable of simulating drillstring whirl and weight lockup under the severe helical buckling. Based on the simulated the post buckling configuration of the string, an automatic interpretation method was proposed to detect the buckling mode and location along the drillstring.
Using the transient dynamics model, the simulation procedure presented in this paper can significantly improve drillstring buckling and post-buckling predictions and help mitigate buckling risk in well planning and execution phases.
Thermodynamic Basis for Brine Density as a Function of Pressure, Temperature and Chemical Composition in Deepwater and XHPHT Environments
Authors: Rahman S. M. , Sathuvalli U. B. , Suryanarayana P. V. 
Published: February 2020

Abstract
In the computation of annular pressure build-up (APB), the pressure-volume-temperature (PVT) response of the annular fluids is of paramount importance. Though the physics of APB is well understood, there is uncertainty in the thermophysical properties of the fluids in the wellbore annuli, especially in the case of brines. Often brines must be used behind the production tieback because of the constraints imposed by the tubing leak and the abandonment leak loads. While custom tests can be performed to determine brine PVT, they can be time consuming and expensive. In this light, our paper presents a method to determine the density of brines from their chemical composition, as a function of pressure and temperature. It compares theoretical predictions with results of tests on brines used in our industry and available test data from the oil and gas and other industries.
In 1987, Kemp and Thomas (1987) used the principles of chemical thermodynamics to develop equations for the density of brines as a function of pressure and temperature and their electrolytic actions. However, their paper contained two (inadvertent, and probably typographical) errors. One of the errors lay in the set of the Debye-Hückel parameters, and the other was contained in the coefficients of the series expansion for the infinite dilution molal volume. Further, they (inadvertently) did not mention the role of a crucial parameter that accounts for the interaction between the ionic constituents of the salt. As a result, nearly a generation of engineers in our industry has been unable to reproduce their valuable results from an important study or apply their technically rigorous results to other brine chemistries.
In this paper, we return to the basic equations of chemical thermodynamics and the principles of stoichiometry and delineate the inadvertent errors that had crept into in the Kemp and Thomas (1987) study. We then present the rectified equations and reproduce their example with the corrected results. Further, we compare the predictions from the original Kemp and Thomas (1987) work with results from other leading chemical engineering models. Finally, we compare the results of theoretical models with test measurements from the lab and characterize the uncertainty inherent in each model.
In summary, we have identified the error in an elegant and important thermodynamic state equation, and rendered it useful once again, to the industry. Further, we demonstrate its validity with new tests and provide uncertainty bounds.
Helical Pipe Viscometer System for Automated Mud Rheology Measurements
Authors: Gul Sercan , Erge Oney , van Oort Eric 
Published: February 2020

Abstract
Optimum well construction operations require frequent and accurate measurements of drilling fluid properties. Optimized hydraulics, hole cleaning and well control requires proper management and characterization of fluid rheology and density. Currently, the methods by American Petroleum Institute (API) standards are used for drilling fluid property measurements. However, these methods are sporadic, labor-intensive and the data quality is highly dependent on the practicing engineer. These dated methods need to be replaced and improved by an automated, continuous and practical way of measuring and monitoring drilling fluid properties.
In this paper, we introduce a helical-pipe viscometer system for automated mud measurements. An automated flow-loop was constructed to perform experiments with Newtonian and non-Newtonian fluids. Flow tests were conducted in two straight- and two helical-pipe test-sections. Frictional pressure loss data was obtained from each section simultaneously. Flow rate, density and temperature data were obtained using a Coriolis flow meter.
It was observed that the toroidal geometry results in secondary flow due to the centrifugal forces. Therefore, elevated frictional pressure losses and delayed transition to turbulent flow were observed in the experiments from the helical-pipe test-sections. A machine-learning regression model was trained using the results from the experimental data for friction factor predictions by the helical pipe pressure loss measurements. The proposed approach was compared with both the experimental data and other theoretical equations reported in the literature. It was observed that the existing correlations in the literature for non-Newtonian fluids are not accurate for the characterization of Herschel Bulkley fluids. Using the trained machine learning model, an algorithm was developed and tested to prove the applicability of the system for automated rheological property determination. Very good accuracy was observed when comparing helical pipe viscometer measurements with standard API measurements.
Helical pipe viscometers offer distinct advantages over standard pipe viscometers, such as compact size and more versatile frictional pressure loss profiles. They are also of interest for the hydraulic design of coiled tubing and slim-hole operations, where the maximum allowable flow rate is often limited by frictional pressure loss.
Using Model-Based Design for Digital Twins to Predict the Real-Time Performance of Surface Equipment
Authors: Johnson Weston , Rao Samvith 
Published: February 2020

Abstract
A digital twin of the above ground electro-mechanical and control systems for a drilling rig was created using a model-based software. Using a library of pre-built software models, reduced the development time of the digital twin using traditional software development methods from over a year with a team of experts, to less than 4 months for a single developer. In addition to a significant time savings, the resulting simulation was able to predict performance of the top drive, draw works and mud pumps with an error of less than 3% for most conditions.
Physics-based twins were built to describe the physical properties of devices (motors, pumps, bus parameters), including material properties, using pre-built block from libraries. These blocks describe mathematics and dynamics of systems. Using sensor data from 3 sensors (Speed, Torque and Current), 16 motor parameters were estimated and calibrated to field data.
Maximizing Drilling Performance Through the Delaware Basin Brushy Canyon and Interbedded Formations
Authors: Dupriest Fred E. , Noynaert Samuel , Cunningham Tyrell , Rendon Marcus 
Published: February 2020

Abstract
The purpose of this study was to develop a physical understanding of the bit damage that occurs in the Brushy Canyon and Avalon formations in the southern Delaware Basin and to develop practices to mitigate it. The operator had already implemented a programmatic initiative to move the organization toward physics-based, limiter-redesign workflows in order to achieve performance gains in a safe and efficient operation. A significant performance limiter was trips for damaged bits.
Two dominant causes of bit damage were observed. One was tangential overload of the outside cutters, which tends to occur if hard streaks are exited with high WOB and depth of cut (DOC). The second is continuous wear of the outside cutters that occurs if lower WOB is used to avoid the tangential overload. There was no operating window in which any given WOB did not enable one or the other form of damage in 12-1/4″ holes.
An explanation of how the overload may occur is presented along with the results of changes in field practices that were consistent with the concept. The progress that was made was partly due to physics-based training of operations personnel which enabled them to interpret observed behaviors and manage dysfunction more intensely. Some elements of the physics-based workflow and training are also discussed at length because they are integral to the improvements achieved in performance (Dupriest 2005, 2006); particularly the use of a Geologic Roadmap and surveillance of the Baseline MSE.
Bits from two wells drilled were pulled green after drilling from the surface casing through the Brushy Canyon. While this is encouraging the results from rig to rig was inconsistent. Bit design needs were identified that should enable higher success, and some of these features are now found in the current market. They were not available at the time of this initiative in 2018.
The nature of the interfacial severity damage varies from the southern to northern end of the Delaware basin, with laminar calcite streaks dominating in the south (the operator's acreage) and nodular chert inclusions occurring in some areas of the north. Both create high loading of a small number of cutter studs and the real time and engineering design practices that limit the interfacial severity damage discussed in this paper may be useful across the basin.
Qualification & Testing of a Powered Wired Drill Pipe Solution
Authors: Silvester Ian , Høgset Tore , Torvund Steinar , Saxena Subodh 
Published: February 2020

Abstract
This paper documents the development, qualification and field test deployment of an electrically powered and wired drill pipe system for use by operators, drillers and service companies in oil & gas drilling operations. Deployment of the technology has the potential for users to power downhole tools from surface and thus reduce or remove downhole batteries / turbines. High-speed bi-directional telemetry over the wired drill pipe can improve realtime communications and downhole measurement quality, while enabling high frequency, surface and downhole data sharing / integration.
The development of the system is centered around: a braided conductor and an insulating materiala robust field replaceable pipe connector systemtransceivers optimized for the transmission characteristics of the system
The novelty of the new drill pipe design is the ability to supply downhole tools with power in addition to bi-directional high-speed data communication telemetry from surface over the same braided and insulated conductor, manufactured into the ID profile of the drillstring. Due to power regulation at surface and matched transceivers, the need for in-string communications repeaters is avoided. In addition, special attention has been paid to the design, robustness and field maintainability of the connector system at each end of the drill pipe.
Qualification of the system in a laboratory environment applied downhole drilling conditions using simulators, highly accelerated life tests ("HALT"), and physical testing on discrete samples, joints and short strings of drill pipe. Transceiver performance, connector make/break cycles and testing of the conductor and insulating layer under tension, bending, torque, pressure, temperature and erosion were all performed. Parallel "real life" runs on testing and commercial drilling rig operations have yielded encouraging early results to validate the qualification laboratory testing. Minimal damage was observed during handling and downhole use on several drilling rigs, indicating that the system has the potential to be handled as regular drillpipe and can be simply integrated into rig operations.
Several iterations in design and testing of the braid and insulating material have proven the viability of new manufacturing techniques and given valuable insight as to the ability of the design to withstand normal drilling conditions of flow, torque, tension, pressure, temperature etc. gained through commercial drilling rig testing. System trials on rig operations have shown that stable downhole power can be delivered whilst communicating with a minimum bit rate of 56Kbit/sec during drilling. A top drive slip-ring assembly at surface and a crossover to a service company BHA downhole have been developed and were used for the drilling trials.