bluuebunny/crossref_metadata_2025 huggingface dataset:
RECEPÇÃO LITERÁRIA DE CONTOS SERGIPANOS
Authors: Gomes Carlos Magno , Vanderlan Ferreira Júlio Flávio
Published: March 2021

Este artigo traz reflexões sobre o modelo de recepção cultural de contos de Antônio Carlos Viana, a partir da aplicação de um projeto de intervenção em uma escola pública estadual de Sergipe. Essa abordagem prioriza valores culturais da região por meio da recepção subjetiva do texto literário e suas conexões com as memórias dos participantes. Metodologicamente, articularemos a proposta de “leitura subjetiva”, de Annie Rouxel, que reconhece a liberação de emoções do leitor como uma etapa do processo de interpretação do texto literário e desenvolvimento do prazer pela leitura; e ampliaremos a abordagem do “modelo cultural de leitura”, defendida por Carlos Gomes, ao destacar as particularidades identitárias locais do leitor no processo de interpretação. Como resultado, apresentamos uma proposta de oficina literária de contos que tematizam a pobreza de narradores atônitos diante da vida degradação de sua família.
Economic disparities in pollution-related mortality in three municipalities of the Metropolitan Area of the Valley of Mexico
Authors:   Instituto Tecnológico Autónomo de MéxicoDepartamento Académico de EstadísticaRío Hondo No. 1, Col. Progreso Tizapán, Ciudad de México, 01080, Islas-Camargo Alejandro , Bohara Alok K. ,   Department of EconomicsThe New Mexico University, USA1915 Roma Ave. Albuquerque, NM 87131, USA, Herrera Ramos J. Mario ,   Facultad Latino Americana de Ciencias Sociales, MéxicoCarretera Picacho Ajusco 377, Héroes de Padierna, Ciudad de México, 14200,
Published: March 2021

This study explored the nature of health risks in the population of three municipalities within the Metropolitan Area of the Valley of Mexico (MAVM) by means of an empirical analysis of health effects associated with air pollution and temperature variation. Based on the environmental justice theory, we asked whether, in unequal socioeconomic municipalities of the MAVM, the association between PM10 concentrations and mortality depends on socioeconomic disparities. We differ from previous studies that have established a relationship between PM10 and mortality based on a state-space model instead of the Poisson regression model. The state-space model allows estimating the size of the unobserved at-risk population, its hazard rate, the life expectancy of individuals in that population, and the effect of changes in environmental conditions on that life expectancy. Our results show a lower hazard rate in a wealthy municipality, as compared to a higher hazard rate in a poor one. The lower hazard rate of the wealthy municipality extends life expectancy and enhances the likelihood of inhabitants staying long-lasting within the population at risk, thus increasing the size of that population, as compared to the population at risk in the poor municipality, whose members show a lower life expectancy. Thus, the smaller the at-risk population, the sicker its average member and the smaller the impact on long-term mortality. Our study examines how regional health disparities could provide information for public health policy initiatives which might improve living conditions among different communities.
Artificial Neural Network Analysis of Geo Database in Diagnosing Papillary Thyroid Carcinoma
Authors: zhang zhoujing , xu di , Akakuru Ozioma , xu wenjing , zhang yewei
Published: March 2021

The diagnosis of papillary thyroid carcinoma has always been a concerned and challenging issue and it is very important and meaningful to have a definite diagnosis before the operation. In this study, we tried to use an artificial intelligence algorithm instead of medical statistics to analyze the genetic fingerprint from gene chip results to identify papillary thyroid carcinoma. We trained 20 artificial neural network models with differential genes and other important genes related to the cell metabolic cycle as the list of input features, and apply them to the diagnosis of papillary thyroid cancer in the independent validation data set. The results showed that when we used the DEGs and all genes lists as input features the models got the best diagnostic performance with AUC=98.97% and 99.37% and the accuracy were both 96%. This study revealed that the proposed artificial neural network models constructed with genetic fingerprints could achieve a prediction of papillary thyroid carcinoma. Such models can support clinicians to make more accurate clinical diagnoses. At the same time, it provides a novel idea for the application of artificial intelligence in clinical medicine.
Living in the Endosymbiotic World of Wolbachia: A Centennial Review
Authors: Kaur Rupinder , Shropshire J. Dylan , L. Cross Karissa , Leigh Brittany , J. Mansueto Alexander , Stewart Victoria , R. Bordenstein Sarah , R. Bordenstein Seth
Published: March 2021

The most widespread intracellular bacteria in the animal kingdom are maternally-inherited endosymbionts of the genus Wolbachia. Their prevalence in arthropods and nematodes worldwide and a stunning arsenal of parasitic and mutualistic adaptations make these bacteria a biological archetype for basic studies of symbiosis and applied outcomes for curbing human and agricultural diseases. Here, we conduct a summative, centennial analysis of living in the Wolbachia world. We synthesize literature on Wolbachia’s host range, phylogenetic diversity, genomics, cell biology, and applications to filarial, arboviral, and agricultural diseases. We also review the mobilome of Wolbachia including phage WO and its essentiality to hallmark phenotypes in arthropods. Finally, the Wolbachia system is an exemplar for discovery-based science education using biodiversity, biotechnology, and bioinformatics lessons. As we approach a century of Wolbachia research, applications, and education, the interdisciplinary science and knowledge from this symbiosis stand as a model for consolidating and teaching the integrative rules of endosymbiotic life.
Tuning the Spatially Controlled Growth, Structural Self-Organizing and Cluster-Assembling of the Carbyne-Enriched Nanostructured Metamaterials during Ion-Assisted Pulse-Plasma Deposition
Authors: Lukin Alexander , Gülseren Oğuz
Published: March 2021

Structural self-organizing and pattern formation are universal and key phenomena observed during growth and cluster-assembling of the carbyne-enriched nanostructured metamaterials at the ion-assisted pulse-plasma deposition. Fine tuning these universal phenomena opens access to designing the properties of the growing carbyne-enriched nano-matrix. The structure of bonds in the grown carbyne-enriched nano-matrices can be programmed by the processes of self-organization and auto-synchronization of nanostructures. We propose the innovative concept, connected with application of the universal Cymatics phenomena during the predictive growth of the carbyne-enriched nanostructured metamaterials. We also propose the self-organization approach for increase stability of the long linear carbon chains. The main idea of suggested concept is manipulating by the self-organized wave patterns excitation phenomenon and their distribution by the spatial structure and properties of the nanostructured metamaterial grows region through the new synergistic effect. Mentioned effect will be provided through the vibration-assisted self-organized wave patterns excitation along with simultaneous manipulating by their properties through the electric field. We propose to use acoustic activation of the plasma zone of nano-matrix growing. Interaction between the inhomogeneous electric field distribution generated on the vibrating layer and the plasma ions will serve as the additional energizing factor controlling the local pattern formation and self-organizing of the nano-structures. Suggested concept makes it possible to provide precise predictive designing the spatial structure and properties of the advanced carbyne-enriched nanostructured metamaterials.
Geomagnetic Induced Current Data Generation and Analysis in Power System Installations
Authors: Ejimofor Chijioke , Eke James
Published: March 2021

Geomagnetic induced current (GIC) is a ground end manifestation associated with the space weather perturbations that should be greatly taken into account by the society. Although the GICs implication to the power system is not regular, it can cause large scale of system failure. In equatorial, the power system is considered safe since the most intense of geomagnetic storm happened in high latitude. However, the internal damage due to GICs which finally led to the South African power system failure has totally changed the normal perception. Therefore, a preliminary investigation on the GICs activity in equatorial region is performed to understand the space weather impact to the power system. Time derivative of the horizontal magnetic field component (dB/dt) is done to indicate the GICs activity value based on Faraday’s law. All the reported power failures are compiled to produce the threshold value of dB/dt, which possibly cause the harmful effect to the system. Then, dB/dt analysis is extended to show the pattern of GICs activity in function of magnetic latitude and local time. The results reveal that power network in equatorial region has possibly suffered by GIC. Plus, high number of intense GIC activity in this region occurred during dayside.
ClefNet: Recurrent Autoencoders with Dynamic Time Warping for Near-Lossless Music Compression and Minimal-Latency Transmission
Authors: Ramesh Vignav , Wang Mason
Published: March 2021

The onset of coronavirus disease 2019 (COVID-19), an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has sparked unprecedented change. Due to the public health guidelines imposed during the COVID-19 pandemic, there is no longer sufficient street traffic for remaining buskers to generate sufficient revenue, leading a majority of street musicians to pursue remote music production. However, real-time music production is notoriously difficult due to the excessively high latencies that current video call platforms such as Zoom and Google Meet harbor. In this paper, we propose an architecture for a platform with end-to-end, near-lossless audio transmission tailored specifically to online joint music production, called Latent Space. We discuss the usage of a recurrent autoencoder with sequence-aware encoding (RAES) and a 1D convolutional layer for audio compression, which we dub ClefNet, as well as propose a new evaluation metric for naive autoencoders (AEs), MSE-DTW loss, which combines the traditional mean square error (MSE) loss function with dynamic time warping (DTW) to prevent an increase in loss when the target sequence predicted by the AE is strictly a temporal variation of the source sequence. Moreover, we detail the logistics of a live system implementation which uses the Web Audio API to extract raw audio samples in real-time to feed into our client-side model before relaying the traffic using peer-to-peer WebRTC technology. The Latent Space platform can be accessed at https://latent-space.tech, and the code and data can be found under the MIT License at https://github.com/rvignav/ClefNet.
Pengaruh Sistem Pendidikan terhadap Perilaku Pencegahan Penyakit HIV/AIDS pada Siswa SMP di Surakarta
Authors: Fajriani Ramadhaningtyas Maghfirotul , Hardjono Hardjono , Sumardiyono Sumardiyono
Published: March 2021

ABSTRAK

Pendahuluan: HIV/AIDS menjadi salah satu masalah utama kesehatan dan sosial karena penyebaran penyakit HIV/AIDS dipengaruhi oleh perilaku individu. Pembentukan perilaku individu dipengaruhi oleh faktor internal dan eksternal, salah satunya adalah lingkungan sekolah. Berdasarkan hasil penelitian sebelumnya ditemukan adanya sikap positif terhadap HIV/AIDS lebih banyak pada kelompok responden di pesantren, namun terbatas hanya pada sikap. Karena itulah, peneliti ingi mencari tahu pengaruh sistem pendidikan terhadap perilaku pencegahan penyakit HIV/AIDS pada siswa SMP yang ada di Surakarta.

Metode: Penelitian ini merupakan penelitian analiktik observasional menggunakan metode potong lintang (cross sectional) dengan jumlah subjek sebanyak 100 siswa. Rincian subjek yaitu 50 siswa bersekolah dengan sistem pendidikan umum (non-boarding school) dan 50 siswa bersekolah dengan sistem pendidikan boarding school. Pengumpulan data dilakukan dengan cara pengisian kuesioner. Hubungan antar variabel dianalisis menggunakan Chi-square dan diolah menggunakan penghitungan statistik

Hasil dan pembahasan: Karakteristik subjek penelitian yang diteliti adalah jenis kelamin, umur, dan pendidikan orang tua. Jumlah laki-laki lebih sedikit (48%) dibanding jumlah perempuan (52%). Umur ditemukan kelompok 14 tahun (68%), 13 tahun (22%), 15 tahun (10%). Pendidikan orang tua ditemukan jumlah tamat perguruan tinggi lebih banyak (52%) dibandingkan tamat SMA (48%).  Hasil penghitungan statistik menggunakan Chi-square menunjukkan sistem pendidikan bermakna secara statistik terhadap perilaku pencegahan penyakit HIV/AIDS pada siswa SMP di Surakarta dengan p=0,009. Hal ini bisa terjadi karena pembelajaran agama yang lebih efisien, pembatasan penggunaan telepon seluler dan akses internet, serta meminimalisir hubungan antara lawan jenis.

Kesimpulan: Terdapat pengaruh yang signifikan antara sistem pendidikan terhadap perilaku pencegahan penyakit HIV/AIDS pada siswa SMP di Surakarta.
The Origin of Terraces in Buried Valleys in the Northwest of the East European Plain
Authors: Karpukhina N.V. , Bricheva S.S. , Konstantinov E.A. , Tatarnikov O.M. , Makkaveev A.N. , Zakharov A.L.
Published: March 2021

—The paper considers the origin of terraces that often complicate the slopes of abnormally deep buried valleys in the northwest of the East European Plain. The Izborsk–Maly valley (Pskov Region, Russia), which is half filled with Quaternary sediments, was chosen as the object of study. Since the upper part of the valley remains unfilled, it is possible to study in detail both geologic and geomorphologic structures of its terraced slopes being of particular interest in the context of the origin of buried valleys and the role of substrate in it. The four denudation-terrace levels that have been identified on the slopes of the Izborsk–Maly valley at absolute elevations of 53, 56–58, 70–72, and 75–77 m formed during the destruction of the preglacial karst landscape under the influence of Pleistocene glaciations. The formation of the terraces was probably linked with several stages of overdeepening of the valley and its expansion by the glacial erosion processes, which corresponded to at least two stages of the ice sheet advance in this area. The last stage may have been the beginning of the Late Valdai (Weichselian) glaciation or the activation of the edge of an ice sheet during its Luga phase (~15.7 cal kyr BP). Results of the study suggest that the Izborsk–Maly valley formed in subglacial conditions. The degree of glacial erosion was determined primarily by the coherence of Devonian carbonate-terrigenous rocks hosting the valley and the degree of the area transformation by karst processes. The cirque shape of slopes is the evidence of karst processes expression in pre-glacial time. Analysis of literature data shows that the origin of denudation terraces in the buried valleys in the northwest of the East European Plain has been paid little attention. The obtained data contribute to the study of this problem and provide insights into the origin of buried valleys.
Correction for Geomagnetic Secular Variation Effects: A New Method (Case Study of the Altai Geodynamic Network)
Authors: Kuleshov D.A. , Dyadkov P.G. , Plotkin V.V.
Published: March 2021

––The study focuses on detection of geomagnetic secular variation and the respective correction of tectonomagnetic data. A new technique is proposed for picking the secular variation component in the Earth’s main magnetic field recorded by precise measurements at 100 to 500 km sites on the surface. Long-period field variations presumably arise from fluid motions in the liquid core, at depths of 3000 km, whereas the sizes of observation networks are within 500 km. The sources of secular variation, irrespective of their configuration, are much deeper than those of tectonomagnetic anomalies located above the Curie surface depths of ~10 to 20 km. Therefore, the surfaces that represent the space distribution of secular variation must be smoother than the respective surfaces for tectonomagnetic anomalies. The problem is thus to separate the regional and local signals from the two types of sources located at different depths. The new method is tested using data of yearly geomagnetic measurements at more than 30 repeat stations of a ~120 km long geodynamic network in Gorny Altai spanning the period from 2004 through 2018. The secular variation pattern is reconstructed by quadratic interpolation. The precise data corrected for secular variation of the main field reveal previously hidden tectonomagnetic anomalies up to 12 nT. The 3 nT positive anomaly falls within the zone of surface deformation caused by the Mw = 7.3 Chuya earthquake of 27 September 2003.
Efficiently Shifting Sliding Sleeves in Extended Reach Horizontal Wells with Electric-Line: A Case Study
Authors: Mauchien Thomas , Kishore Sharat , Olivio Amanda , Ahmed Mostafa
Published: March 2021

Traditional intervention operations with coiled tubing (CT) in extended reach horizontal wells might be difficult to access due to lockup from frictional forces and operational inefficiencies. Using conventional shifting tools requires multiple runs to shift open and close multiple sliding sleeve doors (SSD). This paper is a case study of an electric-line powered shifting intervention operation to shift open an SSD, circulate fluids though the sleeve and into the annulus, and then close and repeat this for another SSD in a long horizontal well—all in a single run.

The paper discusses the different methods that can be used to efficiently seek and latch onto the shifting profiles using a tractor, wireline cable, and the shifting tool itself with an inchworm motion. The electric-line shifting tool monitored and verified the opening and closing of the sleeves in real time using its onboard sensors. These techniques were effectively deployed in multiple wells that required the annulus to be displaced with fluid after running smart completions. The completions were installed in the well with the SSDs in a closed position, and the shifting intervention consisted in opening the SSD, pumping fluids through the sleeve, and closing the SSD. The tool was anchored in place in the wellbore during the entire circulating operation, and the SSD was subsequently closed. This operation was then repeated on the second SSD in the wellbore, and the entire operation was completed in a single run. Also, no additional caliper run was needed as the shifting tool verified the position of the SSDs.

These methods were used in a long horizontal well with the help of real-time measurements. The tool measurements identified if the SSDs were in open or closed position or anywhere in-between. The shifting tool provided confirmation via its measurements that the sleeve was not partially open. This was particularly important when pumping fluid through the annulus to achieve the maximum flow through the sleeve. Operating using electric-line was extremely efficient and eliminated the need to perform multiple runs, thus achieving time savings on the rig.

This is the first time that a paper discusses the different seek methods that can be used for carrying out a electric-line mechanical intervention operation. It represents a novel method using a shifting tool as a caliper to probe and measure the completion inner diameter changes while seeking for the profile. It provides a valuable method for reliably and confidently locating and latching onto a shifting profile. Finally, this is the first time that a paper correlates the theoretical mechanics of shifting a sliding sleeve with consistent results from system integration tests and downhole measurements from the real job.
Fully Automated and Wirelessly Enabled Drillstem Tests: Seven-Zones Campaign Case Study in Sakhalin
Authors: Temer Elias , Subramaniam Deiveindran
Published: March 2021

Well test is one of the crucial steps required to forecast production investments of their fields. However, the operators face many challenges such as reduced capex, exploration budgets, and bad weather conditions that limit the well testing time window. To overcome these challenges, an automated well testing platform enabled a real time monitoring and controlling more zones in a single run for appraisal wells in the Sea of Okhotsk, Russia.

This article highlights the test objectives, the job planning, and automated execution of wirelessly enabled operations in very hostile conditions and limited time period. The use of a telemetry system to well test seven zones allowed real-time data acquisition, control of critical downhole equipment, data transmission to the operator's office in town. Various operational cases will be discussed to demonstrate how automated data acquisition and downhole operations control has optimized operations for both the service company and the operator.
Development of Low Force Shear Blades for High Strength Coiled Tubing
Authors: Sherman Scott
Published: March 2021

As coiled tubing grades have evolved over the past 20 years from 70 grade with a minimum yield strength of 483 MPa (70,000 psi) to 140 grade with a minimum yield strength of 965 MPa (140,000 psi) and wall thicknesses have increased, the resulting force required to shear coil has more than doubled. Most coiled tubing units have a maximum pressure of 20.7 MPa (3000 psi) available for the blow out preventers (BOP) hydraulic circuits. There was an industry need to develop a shear blade for BOPs that could cut high strength coiled tubing using legacy pressure control equipment already in use. Additionally, the new shear blades must create a fish that can be easily retrieved from a wellbore.

Shear strength is estimated using the maximum distortion criterion (von Mises yield criterion) as follows:Shear strength/Yield strength=1√3=.577

Since the maximum distortion criterion is merely an approximation and unique blade geometries are difficult to take into consideration using the above calculation, a considerable amount of hands on lab testing was required to design and optimize an elegant shear blade for cutting high strength coiled tubing with minimal hydraulic forces.

The paper will share the iterative process as novel shear blades were developed that significantly reduced shear forces. Multiple piercing tip geometries were tested, including embodiments with several piercing tips.

Success criteria was reduced shear force, acceptable fish profile on the lower piece of coiled tubing, and no damage to the blades after use. The embodiment that showed the most promise, based on lab testing was further optimized to improve its performance over multiple cuts.

The result was a novel shear blade that is able to cut high strength coiled tubing with 50% of the normal shear force.

As the industry continues to push the limits of coiled tubing with extended reach applications thought impossible only a few years ago, higher strength coiled tubing with increased wall thicknesses will continue to evolve. The new shear blade geometry developed in this project ensures that not only can the latest grades of coiled tubing be sheared in legacy pressure control equipment, but also future grades of coiled tubing that are in development.
Squeezing Perforations Rigless – No Pumping or Injection Required
Authors: Fulks Jeff , Carragher Paul
Published: March 2021

Squeezing perforated intervals is very common in oil and gas wells, either for isolation to produce from another zone or during P&A applications. Though cement is the common material used in this application, sometimes cement is not ideal. A few of these instances are: 1. The formation is too tight to inject a high viscosity fluid like cement. 2. The temperature of the wellbore exceeds the operating temperature of cement. 3. The "void" behind the casing is too large to fill with cement. 4. Remote locations where mobilizing a rig or coil tubing unit is difficult if not impossible.

There is an alternative to cement for "squeezing" perforations that addresses all of these issues, bismuth alloys. Bismuth alloys have a viscosity similar to water and require no pumping or injection into the reservoir. With operating temperatures is up to 325°F, they are suitable for the majority of wells. Unlike cement, bismuth alloys solidify rapidly near the wellbore, isolating the perforations regardless of open volume behind the casing and they are deployed on wireline (rigless).
High Resolution Acoustic Imaging of Plug Related Casing Damage in Hydraulically Fractured Horizontal Wells
Authors: Wardynski Kacper , Battistel Anthony , Littleford Tom , Simpson Greer , Robinson Stephen , Martin Morgan , Anderson Pierce
Published: March 2021

While assessing post-hydraulic-fracture perforation growth using solid-state, high-resolution acoustic imaging tools, it was noted that plug failures were occurring at a high frequency. Though plug failures can be observed from hydraulic fracture surface pressure and flowrate data, the aggregate frequency, causes, and severity of the resulting erosional damage at plug locations was not previously well understood and highly speculative. The sub-millimetric three-dimensional imagery generated from high resolution solid-state acoustic tools significantly improved the industry's awareness of plug failure frequency, mechanisms of failure, and the resulting impact to stimulation efficiency. These acoustic tools helped to uncover the causes and explore possible solutions to failing plugs. This paper presents aggregate data encompassing casing wall loss at over 2700 plug locations and presents emerging trends that appear across the broader dataset. In addition, this paper showcases the usage of high-resolution acoustic imaging in two operator-specific case studies.
Successful Gas Shut Off Operation using a Coiled Tubing Telemetry System: A Case History
Authors: Amirov A. , Hadiaman F. , Parra D. , Zeynalov J. , Kok A.
Published: March 2021

In a deviated well in Caspian Sea gas oil ratio (GOR) increased rapidly in 2017. The result was an oil rate decline with several choke backs to manage GOR build-up. After performing two production-logging jobs, it was confirm that 76% of the gas production was coming from four upper perforations. The main objective was to perform a Gas Shut off (GSO) treatment in two stages to reduce gas production by squeezing polymer into the formation and setting packers at 59° deviation inside 9-5/8 in. casing for temporarily isolation of middle and lower production sands.

Fifteen runs were perform with a tube wire-enabled CT telemetry (CTT) system which consists of a customized bottomhole assembly (BHA) that instantaneously transmits differential pressure, temperature, depth data to surface through a non-intrusive tube wire installed inside the CT. For the first time in the region, a tension, compression and torque (TCT) sub-assembly was deploy to control the entire set/retrieve process with accurate downhole upward/downward forces. CTT technology was a key element to successfully set two Thru Tubing Inflatable Retrievable Packers (TTIRP) by doing casing collar locator (CCL) correlations at tubing end which was 133 m and 228 m (MD) shallower from setting depths. In addition, during second GSO operation, polymer crosslink time was modify based on actual bottomhole temperature recorded with CTT system. Finally, during third GSO treatment placement was improve spotting more GSO system in casing section avoiding further treatments.

After successful placement of the GSO system, a drop from 15.5 to 4.5 MMscf/day in gas production was observed along with GOR reduction from 11,000 to 750 MMscf/bbl and oil rate increment from 1.4 to 6.04 Mbpd. Furthermore, after gas reduction operator was able to produce between 1.5 to 2.0 Mbpd from other wells that were choke back based on gas handling capabilities limitations

The novelty of using the CTT system and TCT sub-assembly for real-time monitoring of BHA data was proven for not only positioning two TTIRP, modifying polymers crosslink design, placing polymer precisely across target intervals and retrieve two TTIRP that at the end provide direct and positive financial impact for the operator.
Underbalanced Drilling with Coiled Tubing: A Case Study on the Alaskan North Slope, Which Proves the Benefits of Drilling a Straight Hole
Authors: Miszewski Antoni , Miszewski Adam , Stevens Richard , Gemignani Matteo
Published: March 2021

A set of 5 wells were to be drilled with directional Coiled Tubing Drilling (CTD) on the North Slope of Alaska. The particular challenges of these wells were the fact that the desired laterals were targeted to be at least 6000ft long, at a shallow depth. Almost twice the length of laterals that are regularly drilled at deeper depths. The shallow depth meant that 2 of the 5 wells involved a casing exit through 3 casings which had never been attempted before. After drilling, the wells were completed with a slotted liner, run on coiled tubing. This required a very smooth and straight wellbore so that the liner could be run as far as the lateral had been drilled.

Various methods were considered to increase lateral reach, including, running an extended reach tool, using friction reducer, increasing the coiled tubing size and using a drilling Bottom Hole Assembly (BHA) that could drill a very straight well path. All of these options were modelled with tubing forces software, and their relative effectiveness was evaluated.

The drilling field results easily exceeded the minimum requirements for success. This project demonstrated record breaking lateral lengths, a record length of liner run on coiled tubing in a single run, and a triple casing exit. The data gained from this project can be used to fine-tune the modelling for future work of a similar nature.
Latest Development in Physics-Based Modeling of Coiled Tubing Plasticity and Fatigue
Authors: Liu Zhanke , Tipton Steven M. , Sukumar Dinesh
Published: March 2021

Coiled tubing (CT) integrity is critical for well intervention operations in the field. To monitor and manage tubing integrity, the industry has developed a number of computer models over the past decades. Among them, low-cycle fatigue (LCF) modeling plays a paramount role in safeguarding tubing integrity. LCF modeling of CT strings dates back to the 1980s. Recently, novel algorithms have contributed to developments in physics-based modeling of tubing fatigue and plasticity. As CT trips into and out of the well, it goes through bending-straightening cycles under high differential pressure. Such tough conditions lead to low- or ultralow-cycle fatigue, limiting CT useful life. The model proposed in this study is derived from a previous one and based on rigorously derived material parameters to compute the evolution of state variables from a wide range of loading conditions. Through newly formulated plasticity and strain parameters, a physics-based damage model predicts CT fatigue life, along with diametral growth and wall thinning. The revised modeling approach gives results for CT damage accumulation, diametral growth, and wall thinning under realistic field conditions, with experimental validation. For 20 different coiled tubing alloys, it was observed that the model improved in accuracy overall by about 18.8% and consistency by 14.0%, for constant pressure data sets of more than 4,500 data points. The modeling results provide insights into the nonlinear nature of fatigue damage accumulation. This study allowed developing recommendations to guide future analytical modeling and experimental investigations, to summarize theoretical findings in physics-based LCF modeling, and to provide practical guidelines for CT string management in the field. The study provides a fundamental understanding of CT LCF and introduces novel algorithms in plasticity and damage.
Degradable Loss Control System for Coiled Tubing Interventions
Authors: Payne Courtney , Rondon Fajardo Sergio
Published: March 2021

Coiled tubing (CT) milling and cleanout interventions depend heavily on the circulation of fluids and debris throughout a wellbore. When these interventions are performed on lateral wells which are subhydrostatic or are not able to sustain a stable column of fluid during the operation, they pose unique challenges. This is mostly due to the inability of the well to support a column of fluid, which consequently causes circulation over long distances and along narrow annular spaces to be difficult or impossible, particularly when a thief zone is present. The many consequences of poor to nonexistent fluid circulation can be severe, ranging from poor hole cleaning and formation damage to inducing a stuck pipe scenario.

Over the years, many mechanical and chemical solutions have been employed to improve fluid circulation in subhydrostatic wells, but each comes with its own set of challenges and can be costly to implement. Two methods commonly used today to improve debris removal from a low-pressure wellbore include the use of nitrogen and the creation of an underbalanced condition in the wellbore by flowing formation fluids. The former is expensive, time consuming, and requires advance bottomhole assembly (BHA) planning whereas the latter can lead to significant formation damage or a reduction in fracture conductivity through the removal of proppant from the near-wellbore area.

A fiber- and particulate-laden degradable loss control system (LCS) is proposed as an improvement on the current techniques used to improve circulation in subhydrostatic wells. The LCS temporarily prevents losses to the reservoir and enables the circulation of debris out of the well. The system was applied to low-pressure wells in North America to demonstrate its effectiveness in addressing the reduction or loss of circulation throughout the wellbore and improving debris transport to surface.
Coiled Tubing Vibration and Premature Failure
Authors: Reichert Bruce , Cravero Sebastian , Valdez Martin , Bunge Jorge
Published: March 2021

A new coiled tubing (CT) failure mechanism has appeared in the past two to three years. The failures occur in CT strings used for frac plug milling in extend reach horizontal wells. The objective of this paper is to investigate a possible cause for these failures. The primary emphasis is analyzing the dynamic response of the CT to axial vibrations induced by a downhole extended reach tool [1], and the resulting tubing material response leading to failure.
Full Well Corrosion Insight – Case Studies in the Added Value of Electromagnetic Thickness Measurements During Well Interventions
Authors: Imrie Andrew , Kozlowski Maciej , Torky Omar , Wijaya Aditya Arie
Published: March 2021

Monitoring pipe corrosion is one of the critical aspects in the well intervention. Such analysis is used to evaluate and justify any remedial actions, to prolong the longevity of the well. Typical corrosion evaluation methods of tubulars consist of multifinger caliper tools that provide high-resolution measurements of the internal condition of the pipe. Routinely, this data is then analyzed and interpreted with respect to the manufacture's nominal specification for each tubular. However, this requires assumptions on the outer diameter of the tubular may add uncertainty, and incorrectly calculate the true metal thicknesses. This paper will highlight cases where the integration of such tool and electromagnetic (EM) thickness data adds value in discovering the true condition of both the first tubular and outer casings.

These case studies demonstrate the use of a multireceiver, multitransmitter electromagnetic (EM) metal thickness tool operating at multiple simultaneous frequencies. It is used to measure the individual wall thickness across multiple strings (up to five) and operates continuously, making measurements in the frequency domain. This tool was combined with a multifinger caliper to provide a complete and efficient single-trip diagnosis of the tubing and casing integrity. The combination of multifinger caliper and EM metal thickness tool results gives both internal and external corrosion as well as metal thickness of first and outer tubular strings.

The paper highlights multiple case studies including; i) successfully detecting several areas of metal loss (up to greater than 32%) on the outer string, which correlated to areas of the mobile salt formation, ii) overlapping defects in two tubulars and, iii) cases where a multifinger caliper alone doesn't provide an accurate indication of the true wall thickness. The final case highlights the advantages of integrating multiple tubular integrity tools when determining the condition of the casing wall.

Metal thickness tools operating on EM principles benefit from a slim outer diameter design that allows the tools to pass through restrictions which typically would prevent ultrasonic scanning thickness tools. Additionally, EM tools are unaffected by the type of fluid in the wellbore and not affected by any non-ferrous scale buildup that may present in the inside of the tubular wall. Combinability between complementary multifinger caliper technology and EM thickness results in two independent sensors to provide a complete assessment of the well architecture.
First Worldwide Slim Coiled Tubing Logging Tractor Deployment
Authors: Duthie Laurie S. , Saiood Hussain A. , Al-Anizi Abdulaziz A. , Moore Norman B. , Correia Carol
Published: March 2021

Successful reservoir surveillance and production monitoring is a key component for effectively managing any field production strategy. For production logging in openhole horizontal extended reach wells (ERWs), the challenges are formidable and extensive; logging these extreme lengths in a cased hole would be difficult enough, but are considerably exaggerated in the openhole condition. A coiled tubing (CT) logging run in open hole must also contend with increased frictional forces, high dogleg severity, a quicker onset of helical buckling and early lockup. The challenge to effectively log these ERWs is further complicated by constraints in the completion where electrical submersible pumps (ESPs) are installed including a 2.4" bypass section.

Although hydraulically powered coiled tubing tractors already existed, a slim CT tractor with real-time logging capabilities was not available in the market. In partnership with a specialist CT tractor manufacturer, a slim logging CT tractor was designed and built to meet the exceptional demands to pull the CT to target depth. The tractor is 100% hydraulically powered, with no electrical power allowing for uninterrupted logging during tractoring. The tractor is powered by the differential pressure from the bore of the CT to the wellbore, and is operated by a pre-set pump rate from surface.

Developed to improve the low coverage in open hole ERW logging jobs, the tractor underwent extensive factory testing before being deployed to the field. The tractor was rigged up on location with the production logging tool and ran in hole. Once the coil tubing locked up, the tractor was activated and pulled the coil to cover over 90% of the open hole section delivering a pulling force of up to 3,200 lb. Real-time production logging was conducted simultaneously with the tractor activated, flowing and shut-in passes were completed to successfully capture the zonal inflow profile. Real-time logging with the tractor is logistically efficient and allows instantaneous decision making to repeat passes for improved data quality.

The new slim logging tractor is the world's slimmest most compact, and the first of its kind CT tractor that enables production logging operations in horizontal extended reach open hole wells. The ability to successfully log these extended reach wells cannot be understated, reservoir simulations and management decisions can only as good as the quality of data available. Some of the advantages of drilling extended reach wells such as increased reservoir contact, reduced footprint and less wells drilled will be lost if sufficient reservoir surveillance cannot be achieved. To maximize the benefits of ERWs, creative solutions and innovative designs must continually be developed to push the boundaries further.
Analysis of Plug Drilling and Stuck Pipe Performance Metrics
Authors: Brown Paul , Gunby Brian
Published: March 2021

A large collection of data recorded during coiled tubing (CT) operations has been analyzed using proprietary pattern recognition algorithms to identify downhole events with a high degree of confidence. These events include the drilling of plugs and stuck pipe incidents. Key performance indicator (KPI) metrics derived from this analysis provide insight into industry trends over time and by region, and can provide useful performance benchmarks for service providers and operator companies.

Depth, weight and pressure data from multiple sources has been streamed and stored on a shared platform over a five year period, creating a record of over 39,000 data files. This data was processed to generate KPI-type statistics for over 500,000 detected plugs and 760 possible stuck pipe scenarios, based on analysis of depth and weight signatures. Using surface measurements to quantify downhole events has some limitations, but the method has proven sufficiently robust to allow useful trends to be observed and evaluated. While the analysis is confidential to the parties involved, a contributing company can compare their ‘performance’ statistics (as evaluated by the third party algorithms) against averages representative of the industry at large, arranged by year and geographic region, to identify areas of relative strength or weakness. An operator company can likewise compare metrics for different service providers (derived solely from jobs performed for their company) for those which elect to share data in this fashion.

This paper presents statistics for plug drilling operations and stuck pipe incidents in North America between 2016-2020, a period of significant change in the CT industry. Examples show how average plug drilling times have generally decreased, with less frequent use of short trips and fewer pipe cycles. The data shows that, for some companies, faster operations have come at the expense of more frequent or severe stuck pipe incidents, whereas other companies have experienced fewer such problems. This comparative analysis illustrates how downhole outcomes can be deduced from surface measurements, and resulting performance metrics can vary widely between companies, fields and geographic regions.
Overcoming Extreme Technical and Logistical Challenges to Successfully Cleanout 76,000-LBM Proppant
Authors: Craig Steven , Soodsakorn Patcharapun
Published: March 2021

A fracture treatment in offshore Tunisia screened out leaving over 76,000-lbm proppant in the wellbore. The well was significantly under-hydrostatic. The platform was small and had limited deck space and low capacity cranes. The completion incorporated chrome tubulars with a history of causing abrasion failure to coiled tubing strings. The challenge was to efficiently and safely clean out the proppant with coiled tubing (CT).

A prior cleanout campaign had been conducted with concentric CT and jet pumps. An initial design focused on repeating this method. The engineering analysis had to account for fluid and nitrogen pumping being conducted from a supply vessel, limited nitrogen volume, low the solids return rate due to surface handling limitations, and no fluid discharge permitted to sea. A combined engineering, logistical study, laboratory testing and risk assessment was undertaken over the course of three months. Engineering utilized advanced cleanout modelling software to review concentric CT cleaning, forward cleaning (with and without optimizing cleaning Bottom Hole Assembly (BHA) and with various sizes of CT), and reverse circulating. Logistics analyzed the overall operation time, fluid and nitrogen requirements and the number of boat trips to replenish/change well returns and nitrogen. Three additional challenges were present. First, proppant could have packed off creating difficulties for some of the processes under review. Laboratory testing was conducted and confirmed this would not be a concern. Second, the well was sour and considerations for protecting the CT string and handling hydrogen sulfide (H2S) in the return stream were required. Third, CT string optimization was required to reduce potential abrasion failures. Avoiding CT failure was paramount as the string would be boat spooled onto the platform and any failure would severely impact operating time and project finances.

The chosen method was primarily fluid only reverse circulating when cleaning above the formation, changing to forward circulated two phase operation when close to the formation. The downhole pressure gauge in the completion provided early warning of lost returns or of gas kicks. The operation was successfully, efficiently and safely completed in August 2019. The well was handed back to production 8 days ahead of schedule.

The paper will cover the complete concept and detail design, execution and post-job analysis.
Pushing the Boundaries of Plug Milling in Deformed Liners – Best Practices and Lessons Learned
Authors: Hamid Saad , Unnikrishnan Vikram , Aljughayman Abdulrahman
Published: March 2021

This paper presents a systematic workflow/methodology developed to evaluate the milling operations using coiled tubing to remove frac plugs in a well with deformed liner, post hydraulic fracturing. This paper also presents the challenges encountered during intervention and steps on how they were mitigated.

The well was completed by hydraulic fracturing of five stages, each separated by a frac plug. Post stimulation, coiled tubing was mobilized to mill the plugs and provide a full bore to begin production. After spending substantial time while attempting to mill in the initial run, decision was made to POOH and inspect the BHA. It was observed that the mill had significant metal loss on the outer periphery with no damage to the mill face, which thereby concluded the presence of liner damage. A strategy was developed on how to remediate this challenge. Multiple coiled tubing diagnostic runs were performed with real-time coiled tubing capabilities, which included cleanout, camera and caliper runs.

Results of each coiled tubing run performed was carefully evaluated to estimate the extent of liner damage. The caliper and video camera runs were important to determine the new reduced ID of the liner. An initial milling attempt with a 3.33" OD mill was performed, which was the smallest size based on the plug manufacturers recommendation. However due to the specific nature of liner damage it could not pass through the restriction. After further discussions, a calculated risk was taken to run with a 3.125" OD mill, which was significantly smaller than the manufacturer's recommendation, and posed an inherent threat of milling through the core of the plug, while leaving the slips intact. This however did not happen, and all four plugs were successfully milled out from the liner, allowing full bore access and well to be flowed back.

This paper will act as a guideline on how to design and execute an intervention operation in deformed liners.