bluuebunny/crossref_metadata_2025 huggingface dataset:
Análise da conformidade à produção integrada de tomate por agricultores familiares de Vilhena (RO)
Authors: Lima Valdique Gilberto de , Paz Diego Oliveira da , Ceresini Paulo Cezar , Macedo Marcos Aurélio Anequine de , Castilho Regina Maria de Monteiro , Sant'Ana Antonio Lázaro
Published: March 2021

A produção de tomate em Vilhena (RO) abastece o mercado local, atendendo inclusive à alimentação escolar pelo Programa Nacional de Alimentação Escolar (PNAE). A adoção de um sistema de produção integrada de tomate que reduzisse o uso de agrotóxicos resultaria na melhoria da segurança alimentar da população local. O trabalho teve como objetivo caracterizar o sistema de produção dos agricultores familiares de tomate, vinculados à Associação dos Pequenos Produtores Rurais do Planalto Parecis - Aprocis, do município de Vilhena, e verificar a possível aderência aos parâmetros da produção integrada (PI). O diagnóstico foi realizado no ano de 2018, por meio de visitas técnicas nas áreas de produção de tomate, nas quais 23 produtores da Associação Aprocis foram entrevistados aplicando-se formulário concebido para detectar o nível de aderência dos produtores à PI. Para a análise dos dados empregou-se estatística descritiva. Constatou-se que os sistemas de produção dos agricultores pesquisados não se enquadram nas normas recomendadas de produção integrada, embora cerca da metade das práticas de PI seja utilizada pelos mesmos, o que indica potencial, desse grupo de agricultores familiares, de adotarem o sistema.
Практические рекомендации по профилактике и лечению тошноты и рвоты у онкологических больных
Authors: Владимирова Л. Ю. , Гладков О. А. , Королева И. А. , Румянцев А. А. , Семиглазова Т. Ю. , Трякин А. А.
Published: March 2021

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Практические рекомендации по лекарственному лечению немелкоклеточного рака легкого
Authors: Лактионов К. К. , Артамонова Е. В. , Бредер В. В. , Горбунова В. А. , Моисеенко Ф. В. , Реутова Е. В. , Сакаева Д. Д. , Смолин А. В. , Тер-Ованесов М. Д.
Published: March 2021

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Практические рекомендации по лекарственному лечению рака яичников, первичного рака брюшины и рака маточных труб
Authors: Тюляндин С. А. , Коломиец Л. А. , Морхов К. Ю. , Нечушкина В. М. , Покатаев И. А. , Румянцев А. А. , Тюляндина А. С. , Урманчеева А. Ф. , Хохлова С. В.
Published: March 2021

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Практические рекомендации по лечению пограничных опухолей яичников
Authors: Давыдова И. Ю. , Ашрафян Л. А. , Карселадзе А. И. , Кузнецов В. В. , Максимов С. Я. , Новикова Е. Г. , Урманчеева А. Ф. , Чекалова М. А.
Published: March 2021

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Практические рекомендации по лекарственному лечению меланомы кожи
Authors: Строяковский Д. Л. , Абрамов М. Е. , Демидов Л. В. , Жукова Н. В. , Новик А. В. , Орлова К. В. , Проценко С. А. , Самойленко И. В. , Трофимова О. П. , Харкевич Г. Ю. , Юрченков А. Н.
Published: March 2021

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Практические рекомендации по лечению анемии при злокачественных новообразованиях
Authors: Орлова Р. В. , Гладков О. А. , Жуков Н. В. , Копп М. В. , Королева И. А. , Ларионова В. Б. , Моисеенко В. М. , Поддубная И. В. , Птушкин В. В.
Published: March 2021

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Практические рекомендации по лечению синдрома анорексии-кахексии у онкологических больных
Authors: Сытов А. В. , Зузов С. А. , Лейдерман И. Н. , Хотеев А. Ж.
Published: March 2021

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Практические рекомендации по заместительной ферментной терапии при раке поджелудочной железы
Authors: Сытов А. В. , Зузов С. А. , Лейдерман И. Н. , Хотеев А. Ж.
Published: March 2021

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Validation of ILS through Exploratory Factor Analysis and Internal Consistency Reliability for Secondary Grade
Authors:   the National University of Sciences and Technology (NUST), Islamabad, Pakistan, Mirza Munazza A. , Khurshid Khawar , Sohail Kinza , Biland Salman , Mirza Asma A.
Published: March 2021

There is a continuous debate on the validity of learning styles in literature. Several models have been proposed for the learning styles, corresponding to the psychometric assessment instrument. Among these models, Felder-Silverman model is widely used by educators to identify the learning styles of the engineering students. The instrument that measures the learning styles is the index of learning style (ILS). This study focuses to identify the validity and reliability of the ILS instrument for middle school students (N=260). This includes internal consistency reliability and construct validity report of the ILS. As a result of the study, the reliability of the instrument was established, however, it was found that there were cross loadings in the 14-factor solution and the 4-factor solution. Thus, the instrument validity for secondary grade students was not established.
Robust estimation of the extreme value index of Pareto-type distributions under random truncation with applications
Authors: Djabrane Yahia , Abida Zahnit , Brahim Brahimi
Published: March 2021

In this paper, we introduce a new robust estimator for the extreme value index of Pareto-type distributions under randomly right-truncated data and establish its consistency and asymptotic normality. Our considerations are based on the Lynden-Bell integral and a useful huberized M-functional and M-estimators of the tail index. A simulation study is carried out to evaluate the robustness and the nite sample behavior of the proposed estimator.  Extreme quantiles estimation is also derived and applied to real data-set of lifetimes of automobile brake pads.
Poisson Transmuted-G Family of Distributions: Its Properties and Applications
Authors: Handique Laba , Chakraborty Subrata , Eliwa M.S. , Hamedani Dr. G.G.
Published: March 2021

In this article, an extension of the transmuted-G family is proposed, in the so-called Poison transmuted-G family of distributions. Some of its statistical properties including quantile function, moment generating function, order statistics, probability weighted moment, stress-strength reliability, residual lifetime, reversed residual lifetime, Rényi entropy and mean deviation are derived. A few important special models of the proposed family are listed. Stochastic characterizations of the proposed family based on truncated moments, hazard function and reverse hazard function, are also studied. The family parameters are estimated via the maximum likelihood approach. A simulation study is carried out to examine the bias and mean square error of the maximum likelihood estimators. The advantage of the proposed family in data fitting is illustrated by means of two applications to failure time data sets.
Membangkitkan Ekonomi Rakyat Secara Berjamaah Melalui Koperasi
Authors: Fitriati Ulfa
Published: March 2021

Program Kemitraan Masyarakat (PKM) kewirausahaan berupa sosialisasi koperasi syariah 212 di Kota Banjarbaru dibantu oleh 6 orang mahasiswa Teknik Sipil.  Koperasi adalah sebuah organisasi ekonomi yang dimiliki dan dioperasikan oleh orang-seorang demi kepentingan bersama. Koperasi melandaskan kegiatan berdasarkan prinsip gerakan ekonomi rakyat yang berdasarkan asas kekeluargaan.  212 Mart adalah merek minimarket Koperasi Syariah 212. 212 Mart menjual barang kebutuhan sehari-hari masyarakat seperti bahan pokok, perlengkapan rumah tangga, alat tulis, dll. Berbeda dengan minimarket pada umumnya, 212 Mart tidak menjual rokok, minuman keras, alat kontrasepsi dan produk yang tidak halal.  Dalam menjalankan bisnisnya, 212 Mart memberikan lapak kepada pelaku Usaha Mikro, Kecil, dan Menengah (UMKM) untuk dapat menjual produknya. 212 Mart buka mulai pukul 8 dan tutup pada pukul 21 setiap hari. Setiap waktu shalat, 212 Mart menutup gerai tokonya selama lebih kurang 15 menit.  Hasil sosialisasi anggota Koperasi Syariah 212 Amanah Idaman Banjarbaru bertambah 90 orang, semula 44 orang anggota di bulan Februari 2019 hingga 7 Juli 2020 sudah mencapai 134 orang. Dengan simpanan total mencapai 300 juta lebih.  Hal ini menunjukkan hanya sebagian masyarakat yang tahu bahwa koperasi adalah usaha berjamaah dengan modal kecil untuk meningkatkan ekonomi masyarakat.
Spain: Opinion on European Integration
Authors: Cherkasova E.
Published: March 2021

The article analyzes the changes that characterize Spanish approach to political aspects of European integration, and more specifically, the approach of different political parties to the process. Spanish political circles and even think tanks pay relatively little attention to theoretical aspects of European integration, whereas practical relations with the EU are of paramount importance. This is due to the fact that the question of belonging to the EU was settled in Spain long ago and definitively. Majoritarian character of Spanish democracy facilitates the transfer of powers from Brussels to Madrid, i.e. objectively favors the choice of federalization. Nevertheless, Spain continues to upload its national preferences onto the EU decision-making process. In recent years, Spain’s influence and authority in the EU have declined because of the economic crisis. This loss of authority will be overcome as soon as the economic growth is resumed. Constantly emphasizing its belonging to the core of the EU, the “Old Europe”, and to the core of the euro zone, maintaining close relationship with the Latin group within the EU, Spain has consistently advocated a united and strong Europe with a Common Foreign and Security Policy.
Institutional Component of Agrarian Reforms
Authors: Nochevkina L.
Published: March 2021

The article analyzes the influence of the institutional factor on the process of market transformations in the Russian agrarian sector from the point of view of the institutional theory, namely the transaction costs concept. The author highlights the Russian specifics and the differences of land reforms in this country from those in such countries as Japan, Germany, Scotland, Thailand, and Brazil. The paper provides an in-depth analysis of the relationships between state authorities and landowners, as well as between diverse property regimes. According to this analysis, there are two most significant factors that defined the content and result of the agrarian reforms in Russia: (1) weakness of legal institutions, (2) lack of control over realization and protection of property rights. The author concludes that high transaction costs turned to be the main obstacle during the formation of the land market in this country. Virtually total absence of government’s involvement in the minimization of transaction costs is pointed out. At the same time, according to the international experience, such involvement proved to be essential for eventual success of agrarian reform. As a result of institutional deficiencies Russia faces an absolute reduction of cultivated land and a loss of interest in land as a subject of management or as an attractive investment asset. A matter of special examination of the article is the multiplicity of property regimes in the Russian agrarian sector. They are presented by the farmers, agroholdings, mega-farms, small agribusiness, and agricultural cooperatives. The final conclusion of the author’s analysis of the existing property regimes is that all of them still lack economic viability because of the fundamental institutional deficiencies of land reform in this country.
Drama of the Arab East
Authors: Mirskii G.
Published: March 2021

New upheavals have shaken the Middle East this summer. A small but determined army of Sunni jihadists that had operated in the war-torn Syria suddenly crossed the border into Iraq and launched a large-scale military campaign. In a matter of days the invaders captured the second largest city of Iraq, Mosul, and although heavily outnumbered by the Iraqi army, put it to flight. The militants, known as ISIS (the Islamic State of Iraq and Sham, the latter word meaning Syria and Lebanon) and led by an exceedingly tough and ruthless commander Abubaqr al-Baghdadi, are descendants of the infamous terrorist international network Al-Qaeda. Actually, the ISIS members represent the third generation of Al-Qaeda militants who waged the war against the Soviet Army in Afghanistan back in 1989-s and later fought the Americans in Iraq in the wake of the U.S. invasion. Lately they joined the Syrian armed opposition that has been trying to overthrow the regime of Bashar al-Assad for about three years. Now that the military situation in Syria appears to favor the embattled president, ISIS has probably come to the conclusion that its priority is not necessarily the ousting of Assad; rather it is the creation of an Islamic state according to the name of their organization. Exactly this seems to be the rationale for their comeback into Iraq. The Sunni jihadists whose ultimate aim is to resurrect the medieval Islamic Caliphate have to confront both the Iraqi Kurds who live in a virtually semi-independent state formation and the Shia Arabs who mostly inhabit the southern part of Iraq. Yet, both communities, although probably capable of protecting North, South and the capital city, are hardly likely to reassert the government authority in the central part of the country. What is necessary is the assistance from abroad. The Shia-dominated Iraqi government of Nouri al-Maliki, in deep trouble, is looking to both Iran and the U.S. for military aid. Both Washington and Tehran, however, appear reluctant to be seen as wholeheartedly backing the Shia side if only for fear of alienating the mainstream Arab States who are of course Sunni. This is a pretty delicate situation indeed.
Viewpoint: The Current Advances and Future Optimization of Blood-based Tumor Mutation Burden as a Biomarker for Cancer Immunotherapy
Authors: Li Anlin
Published: March 2021

Instead of tissue-based detection, blood-based tumor mutation burden (bTMB) is becoming an alternative promising alternate to predict the response of immune checkpoint inhibitor in cancers, especially non-small-cell lung cancer. Although bTMB is more convenient and less invasive, many evidences identified its limited predictive ability and less accurate discrimination of candidates to receive immunotherapy. Several ways of adjustments have been applied to improve the clinical usefulness of bTMB, such as setting restriction for threshold of allele frequency to exclude some unwanted mutations. But many questions remained to be explored such as the number and the type of mutations that should be incorporated into the bTMB estimation. This viewpoint summarized the current attempts to modify bTMB and provided granular aspects that have implications for further enhancement of bTMB’s predictive capability.
Reliability of a Barre-Mounted Dynamometer-Stabilizing Device in Measuring Dance-Specific Muscle Performance
Authors: Strzelinski Melissa , Brody Lori Thein , Smith Jo Armour , Bronner Shaw
Published: March 2021

BACKGROUND: Hand-held dynamometry is considered an efficient, effective, and portable means of objectively measuring lower extremity strength; however, it has yet to be studied specific to dance-relevant muscle performance. Also, dynamometry is often criticized for variability in results
based on tester strength and sex. Use of an external stabilizing device has been suggested to minimize differences in outcomes between male and female testers by reducing variability associated with tester strength limitations. Therefore, this study used a barre-mounted, portable dynamometer
stabilizing device to improve consistency of results among different testers for assessing hip and lower extremity muscle performance in dance-relevant positions. OBJECTIVE: To assess the intra and inter-rater reliability of a barre-mounted dynamometer stabilizing device in measuring muscle
performance in common dance maneuvers. METHODS: Two testers assessed muscle performance of three common dance maneuvers-—développé en avant, à la secondé, and arabesque-—on 11 pre-professional and professional dancers on two separate occasions to establish
intra- and inter-rater reliability of the barre-mounted dynamometer stabilizing device. RESULTS: Intra-rater reliability was moderate to high and inter-rater reliability of the device was excellent, with intraclass correlation coefficients ranging from 0.527–0.851 and 0.834–0.953,
respectively, for all positions. CONCLUSIONS: The barre-mounted stabilizing device shows promise in mitigating tester strength or fatigue in assessing muscle performance of dancers. Initial assessment of the device suggests further study may be indicated to improve generalizability to applications
of larger-scale muscle performance screening and assessment in dancers or other athletic populations who engage in movements that require extensive hip range of motion and multi-joint stability. CLINICAL RELEVANCE: Using a portable, barre-mounted stabilizing device in assessing multi-joint
lower extremity muscle performance in dancers improves consistency of testing results. Application of this testing device into wider scale screenings could assist in developing normative data for a population that is lacking.
Kinematic Analysis of the Coupling Between Calcaneal Eversion and Ankle Dorsiflexion in a Contemporary Dancer’s Demi-Plié
Authors: Schrefl Anna , van de Langenberg Rolf , Schärli Andrea
Published: March 2021

BACKGROUND: Dancing requires a high range of motion in the foot as well as a good shock-absorbing system formed by the foot and ankle joints. Although there is a broad consensus in dance that excessive calcaneal eversion can cause injury and should be avoided, calcaneal eversion is
discussed controversially in the dance literature. An increased research focus on the biomechanics of dance, particularly research pertaining to the foot and ankle joints, might help to resolve this controversy. OBJECTIVES: The study’s main purpose was to generate hitherto lacking kinematic
data of calcaneal eversion in a dancer’s demi-plié. METHODS: Thirty-two contemporary dancers performed three trials in two different conditions: demi-plié in parallel and in turned-out positions. The motion capture system FASTRAK was used to measure calcaneal eversion and
foot and lower leg alignment during demi-plié. RESULTS: Maximal calcaneal eversion in turned-out demi-pliés was 3.36°±4° and total range of motion (i.e., maximal minus minimal angle) of calcaneal eversion was 3.73°±1.42°, where the large standard
deviations indicate substantial variability across participants. Calcaneal eversion was significantly different between turned-out (3.36°±4°) and parallel (1.17°±4.06°) demi-pliés, as was the alignment of the lower leg and foot, where the lower leg tracked
more medially relative to the foot during turned-out pliés. Crucially, both the magnitude of calcaneal eversion and its temporal coupling with ankle dorsiflexion were highly variable across participants. CONCLUSIONS: Average calcaneal eversion is a poor indicator of the role calcaneal
eversion plays in the demi-plié of contemporary dancers. Rather, the temporal coupling between calcaneal eversion and ankle dorsiflexion needs to be considered.
DAKWAH DI TENGAH PANDEMI (STUDI TERHADAP RESPONS DAI DI MEDIA SOSIAL)
Authors: Hidayati Diajeng Laily , Fahlevi Reza
Published: March 2021

The Covid-19 (Corona Virus Disease-19) outbreak has managed to change the patterns of social life on society, including the change regarding the way Da’wa is performed; from conventional direct Da’wa to mediated Da’wa through internet. This article aims at describing responses of the Da’is (proselytizers) in social media pertaining to the spread of the Covid-19. This article applied qualitative method to analyse Da’wa contents related to Covid-19 on social media. Data were collected through observation and documentation. Findings show that there are at least three types of responses from the Da’is; cognitive, affective, and behavioural responses.  Cognitive response is manifested in the form of delivering information regarding Covid-19 from the general and medical perspective such as promoting frequent hand-washing, maintaining good hygiene, obeying the government measurements, maintaining healthy level of gratitude and praying to God to be saved from the outbreak. Affective response is manifested in the form of promoting empathy, positive thinking, and avoiding panic. Behavioural response is manifested in the form of giving real-life example such as performing online congregation (pengajian online), wearing face mask, applying appropriate disinfection, and helping those heavily affected by the outbreak.Keywords: Covid-19, Dai, responses, and social media.
Alluvial Fan Alteration Due to Debris-Flow Deposition, Incision, and Channel Migration at Forest Falls, California
Authors: Cato Kerry , Goforth Brett
Published: March 2021

Historical patterns of debris flows have been reconstructed at the town of Forest Falls in the San Bernardino Mountains using a variety of field methods (mapping flow events after occurrence, dendrochronology evidence, soil chronosequences). Large flow events occur when summer thunderstorms produce brief high-intensity rainfall to mobilize debris; however, the geomorphic system exhibits properties of non-linear response rather than being a single-event precipitation-driven process. Previous studies contrasted the relative water content of flows generated by varying-intensity summer thunderstorms to model factors controlling flow velocity and pathway of deposition. We hypothesize that sediment discharge in this geomorphic system exhibits multiple sources of complexity and present evidence of (1) thresholds of sediment delivery from sources at the higher reaches of bedrock canyons, (2) storage effects in sediment transport down the bedrock canyons, and (3) feedbacks in deposition, remobilization, and transport of sediment across the alluvial fan in dynamic channel filling, cutting, and avulsion processes. An example of the first component occurred in March 2017, when snowmelt generated a rapid translational landslide and debris avalanche of about 80,000 m3; this sediment was deposited in the bedrock canyon but moved no farther down gradient. The second component was observed when accumulation of meta-stable sediments in the bedrock canyon remained in place until fluvial erosion and subsequent debris flow provided dynamic instability to remobilize the mass downstream. The third component occurred on the alluvial fan below the bedrock canyon, where low-water-content debris flows deposited sediments that filled the active channel, raising the channel grade level to levee elevation, allowing for subsequent spread of non-channelized flows onto the fan surface and scouring new channel pathways down fan. A conceptual model of spatial and temporal complexities in this debris-flow system is proposed to guide future study for improved risk prediction.
Detecting Pressure Anomalies While Drilling Using a Machine Learning Hybrid Approach
Authors: Lafond Aurore , Ringer Maurice , Le Blay Florian , Liu Jiaxu , Millan Ekaterina , Ba Samba , Chao Mu
Published: March 2021

Abnormal surface pressure is typically the first indicator of a number of problematic events, including kicks, losses, washouts and stuck pipe. These events account for 60–70% of all drilling-related nonproductive time, so their early and accurate detection has the potential to save the industry billions of dollars. Detecting these events today requires an expert user watching multiple curves, which can be costly, and subject to human errors. The solution presented in this paper is aiming at augmenting traditional models with new machine learning techniques, which enable to detect these events automatically and help the monitoring of the drilling well.

Today’s real-time monitoring systems employ complex physical models to estimate surface standpipe pressure while drilling. These require many inputs and are difficult to calibrate. Machine learning is an alternative method to predict pump pressure, but this alone needs significant labelled training data, which is often lacking in the drilling world. The new system combines these approaches: a machine learning framework is used to enable automated learning while the physical models work to compensate any gaps in the training data. The system uses only standard surface measurements, is fully automated, and is continuously retrained while drilling to ensure the most accurate pressure prediction. In addition, a stochastic (Bayesian) machine learning technique is used, which enables not only a prediction of the pressure, but also the uncertainty and confidence of this prediction. Last, the new system includes a data quality control workflow. It discards periods of low data quality for the pressure anomaly detection and enables to have a smarter real-time events analysis.

The new system has been tested on historical wells using a new test and validation framework. The framework runs the system automatically on large volumes of both historical and simulated data, to enable cross-referencing the results with observations. In this paper, we show the results of the automated test framework as well as the capabilities of the new system in two specific case studies, one on land and another offshore. Moreover, large scale statistics enlighten the reliability and the efficiency of this new detection workflow. The new system builds on the trend in our industry to better capture and utilize digital data for optimizing drilling.
The Value of Integrated Downhole Passive Acoustic Monitoring During an Extended Leak Off Test to Prove Formation Integrity. A Case Study
Authors: Volkov Maxim , Björk Henric , Kudriavaia Natalia , Andrews Jamie Stuart , Carlsen Truls , Strøm Steinar
Published: March 2021

The Extended Leak Off Test (XLOT) is a sophisticated formation integrity test that can be performed during drilling, recompletion, or at the well abandonment stage. The test is usually characterized by multiple cycles, creating and manipulating a fracture that can extend several meters away from the wellbore. The test can provide more data (both formation stress and fracture mechanics) compared to traditional leak-off tests. This data is used extensively both for determination of the in-situ formation stress for well barrier integrity assessment and for more general rock mechanical work such as quantifying fracture gradient for use in wellbore stability programs for drilling and completion operations.

The interpretation is performed by analysis of the surface pressure and, often with downhole data from memory gauges (or, increasingly, with real-time data from wired pipe) at different stages of the XLOT test. The typical XLOT pressure analysis chart is shown below (see Fig.1). The key determined parameters are:–Leak Off Pressure (LOP)–Fracture Initiation Pressure (FIP)–Formation Break Down Pressure (FBR)–Formation Propagation Pressure (FPP)–Instantaneous Shut-In Pressure (ISIP)–Formation Closure Pressure (FCP)–Fracture Reopening Pressure (FRP)Figure 1The traditional XLOT interpretation plot.

A key requirement of the test is to ensure hydraulic connectivity to the targeted formation only. This can be achieved in the case where annulus barriers are in place and perform well. Unintentional communication to non-targeted zones may result in abnormal behavior, more complex interpretation of obtained data, larger uncertainty in the meaning of the results and ultimately failure of the XLOT test.

To verify the well barriers integrity prior to the XLOT different techniques can be utilized. The main one is cement bond logging across the cemented barriers. This indicates the condition of the cement behind the first casing and increases the level of confidence the test will be conducted successfully. "However, recent case studies have shown that an indication of good bond above and/or below the target formation from a cement bond log cannot guarantee the isolation required to sufficiently hold the applied pressure [Maxim Volkov]."

The paper demonstrates an approach taken by Equinor in a special application where XLOT testing was advanced by adding downhole monitoring during the test. This targeted the following parameters to evaluate the new essential components of XLOT interpretation: –depth and capacity of opened and re-opened fractures,–actual sealing of the cement barriers above and below the targeted zone,–failure investigation in case the FBP cannot be achieved.
Failure Modes and Root Cause Analyses of Advanced Drill Collar Connections
Authors: Du Michael Hui , Li Ke , Song Fei , Li Haoming , Smith David L. , Blackman Wesley
Published: March 2021

Advanced drill collar connections have been developed with 10 times extended fatigue life compared with the corresponding replaced connections. More than 4,000 advanced connections have been run in North America. Although these connections have demonstrated substantial fatigue strength improvement in operation, some failures have occurred. Multiple failed connection samples have been retrieved and analyzed for their failure modes and the root causes.

In the failure analyses, manufacturing data were reviewed to identify any possible discrepancies between design specifications and manufactured components. The field run data were analyzed for the loading histories of the connections. The downhole fluid properties were also reviewed to identify their possible effects on the connection performances. The bottom hole assemblies were numerically analyzed to determine the loading distributions. The failed connection samples were physically processed and inspected in the metallurgical laboratory. Based on the combined numerical and testing analyses, the conclusions on the failure modes and the root causes were drawn.

It was found that the primary failure mode for these connections was fatigue. The root causes for the fatigue failures can be divided into two categories: manufacturing causes and operational causes. Among the manufacturing failure causes, incorrect cold rolling is the primary one. The operation related failures were mainly caused by overloading.

Through failure mode and root cause analyses, the manufacturing and operational related risks for the advanced drill collar connections were mitigated accordingly. It therefore greatly improved the quality assurance of the advanced connections.
An Introduction of Drilling Data Space
Authors: Merciu Ioan-Alexandru , Kjørholt Halvor
Published: March 2021

Traditional well planning and drilling risk management requires revisiting past experiences for a given drilling volume and it is expected that new well project evaluation requires multidisciplinary teams and plurality of data usage and access. To date, there is little integration of drilling data and mud logs into decisional data space used for well planning. Integration of drilling data and mud logs into models used for well planning allows for the data to be analyzed and used for evaluation in order to answer questions such as: will we encounter stringers? What is the expected ROP during the project? How can I de- risk the project in planning phase?

We have developed a methodology to allow well planning and associated subsurface models to be created in geo-referenced drilling data space. At the heart, the method requires to build the static subsurface model using historical well trajectory, drilling data and mud log data. From this point of view the subsurface mathematical data space becomes pure drilling space where first the drilling data will populate the virtual space coordinates, allowing all otherwise standard 3D interpolation and intersect techniques to be used. Our approach provides flexibility and completeness for the data distribution as all the wells have past recorded drilling data while other sources of data may be very sparse such in the case of petrophysical or seismic data.

We have tested this approach on data from one field and the methodology is robust for using historical data to populate the model and plan new wells. Using driller definitions, we have built an expedite method to detect stringers and match the new observations with sub-seismic events and petrophysical evaluations. The potential application of this method beyond what we have tested is the possibility for scale up and perform rapid comparative exercise with other information and data sets. Sources of uncertainty and possible propagation of such through drilling data space is briefly introduced.

Having a historical database of drilling data in geo-referenced space gives confidence to well planning, helps the drilling team to get updated drilling information and perform risk management prior to drilling.
Novel Surfactant for Spacer-Less Cementing Compatible with Non Aqueous Fluids
Authors: Wee Joseph K. , Gomes Paulo , Huang ShanShan , Therond Emmanuel , Dieker Ansgar Heinrich, , Daulton Daniel J. , Doan Angela , Kellum Matthew Grady , Perez Cresencio
Published: March 2021

A novel, non-ionic surfactant is presented that alters typical cement incompatibility with non-aqueous fluids, effectively removing synthetic/oil-based mud (SOBM) from the wellbore and changing wettability of casing and formation from oil-wet to water-wet. The change in wettability eliminates the need for cement spacers conventionally deployed between the preceding non-aqueous fluid and the ensuing cement slurry. The entirety of spacer fluid interface can therefore be removed from operation, improving operational safety and efficiency, reduce waste and simplify wellsite logistics. The paper discusses the selection and evaluation of the proprietary surfactant in various laboratory testing. The main characteristics of the surfactant is its non-foaming, non-retarding, compatible with SOBM, ability to change oil-wet surface to water-wet, stable while minimizing environmentally impact. Scaling up, a yard test and a field trial in an offshore rig was successfully performed to evaluate the mixing, compatibility and pumpability using rig equipment.
Real-Time Lookahead Imaging Using the Drill Bit as Seismic Source
Authors: Goertz Alexander Valentin , Thiem Tatiana , Bergfjord Endre Vange , Libak Audun , Atkinson Brian , Bussat Sascha
Published: March 2021

We monitor the seismic signal emitted from a rotating drill bit in real time with an array of seismic sensors at the seafloor. Drill-bit seismic signals provide information to locate the drill-bit position itself and to image geological objects ahead and around the drill bit for geosteering purposes during drilling operations. The data can be obtained in real time without the need to stop drilling for logging and without any additional downhole instrumentation in the bottom hole assembly. Drill-bit positioning accuracy is independent of measured depth and with meter level lateral precision. This is significantly better than conventional downhole gyro-based methods, especially for long horizontal wells. With sources along the drilled well path approaching a target reservoir we obtain a 3D reverse VSP (RVSP) image around the well for prediction ahead of the drill bit. This paper presents a case study from the Grane reservoir in the North Sea, where we utilize a permanent reservoir monitoring (PRM) array for listening to signals emitted from drilling with a PDC bit. We present imaging results from a highly deviated well and compare them to 3D seismic. The field example shows the ability to look ahead several hundreds of meters below the drilled well trajectory.
A Study on the Impact of Rheological Measurement Technique on Pressure Loss Estimation Uncertainty
Authors: Iversen Fionn , Brevik Jan Ove , Taugbøl Knut
Published: March 2021

Drilling fluid rheology measurements provide input to flow frictional pressure loss calculations during drilling operations. This study compares the impact of uncertainty of different rheology measurement methods on pressure loss estimation through a series of flow-loop experiments.

The rheological properties of drilling fluids are measured using a high precision Anton Paar rheometer, in-line pipe rheometer and conventional model 35 lab viscometers. The derived viscosity is used to calculate the frictional pressure loss with uncertainty, comparing with in-situ pressure loss observations from flow-loop experiments. The experiments are performed for steady-state, laminar horizontal pipe flow at atmospheric pressure.

The results illustrate the impact different measurement techniques have on the accuracy of the modelled frictional pressure loss. The potential of the pipe rheometer is investigated with respect to use of measured frictional pressure loss data to predict pressure loss in wells and annulus directly. Finally, the effect of variation in the rheological properties have been illustrated on a simulated case downhole.

This study highlights differences in uncertainty range for conventional viscometers in comparison to a high precision rheometer and the propagation of uncertainty to the frictional pressure loss estimation. Quantification of the uncertainty of the modelled frictional pressure is essential information for application of downhole pressure estimation in managing the drilling process. The existing procedure of using conventional viscometers may not be sufficient when accurate pressure control is needed.
A Novel Approach to Drill Stem Selection for Drilling in Sour Fields
Authors: Plessis Guillaume , Muradov Andrei , Bordet Laurent , Griffin Richard , Hehn Lucien
Published: March 2021

For years the drilling industry has used sour service drill pipe within a narrow set of specifications and industry guidelines. That left room for original equipment manufacturers (OEM) to have customization on an iterative basis, which resulted in a wide product offering to fulfill operator needs. While this method worked, it did not lead to building the product in the most efficient and economical manner.

As a result of this product diversity, drilling engineers could specify the best product to deliver their projects when running drilling models, only to have to redesign it around what is effectively available on rigs or for rental. This disconnect puts pressure on the industry players and is the result of a lack of standardization.

We wiped the board to provide a simple solution that is more suited to allow alignment between operators, contractors, and rental companies. The new philosophy is based on the National Association of Corrosion Engineers (NACE) MR0175-2015 severity diagram, where environmental severity is defined in regions (1, 2, and 3), which have been used by oil companies’ engineers for their oil country tubular goods (OCTG) product selection. Even though the drill string will not be exposed to the well fluid for the same extended time and is surrounded by a more forgiving medium, the drilling fluid, the diagram allows a segmentation of customer's needs.

This framework helped define targeted product properties. A research and development (R&D) and industrialization test campaign could then be started to confirm that sound product configurations could be offered with targeted properties.

The study also explored the limitations imposed on connection make-up torque in a sour gas environment relative to the NACE severity diagram. Emphasis was given on methods to increase the make-up torque, which is needed to deliver the most extended reach wells that are now commonplace.

The result of this two-year development campaign is a short list of grades with an optimized balance between pipe subcomponents strength and sulfide stress cracking (SSC) resistance. Region 1 (mild severity) products will offer as much tension and torque as possible, matching or exceeding these of API products, including excellent resistance to SSC, thus making drilling operation safer. Region 2 (medium severity) will offer products with medium to high strength and enhanced SSC resistance. Finally, region 3 (high severity) products will be aligned with the industry specifications for maximized SSC resistance and lower strength.

This paper discusses a proactive approach that contrasts with a historical, more reactive one. As the drill stem technology leader, we saw an opportunity to drive this initiative that will benefit the drilling industry by offering a more natural way to select drill stem products.

For the first time a sour service product range aligns with the needs of drilling engineers and the inventory of their selected service companies.
Drilling Advisory for Automatic Drilling Control
Authors: Lahlou Kenza , Oedegaard Sven Inge , Svendsen Morten , Weltzin Tore , Bjørkevoll Knut Steinar , Rudshaug Bjørn
Published: March 2021

This paper describes a system being developed for providing an optimized real-time decision support with automatic forward-looking and what-if simulations. It will address the challenge of achieving automation, better performance, and avoidance of non-productive time (NPT) in drilling operations. It will additionally address the demanding human support currently required in the entire decision support workflow.

The approach includes utilization of Model based reasoning in Artificial Intelligence (AI) with a Digital Twin combined with Machine Learning (ML) and advanced 3D visualization which is a key enabler for operation alerts and optimization. Multiple forward-looking and what-if simulations will also be run in real-time to find optimal parameters for flow, rotation and running speed. A Diagnostic module will detect abnormalities and trigger safeguards.

Auto-configuration and auto-calibration will be the key elements for Drilling Advisory system and deployment without the need for back-office support. The personnel involved in the operation (drilling contractor, service provider and operator) will be able to quickly provide the necessary operational input and then the system will be auto-calibrated during the operation.

Results will be an Advisory Tool providing the operation with an optimal flow, rotation speed and running speed during Drilling, Tripping, Casing/liner/screen running and cement operations in two applications areas:

In front of the driller as an Advisory tool for rigs with legacy drilling control systems not capable of receiving automated instructions. Base for providing direct commands and safeguards to rigs with control systems capable of receiving automated commands of optimal flow, rotation speed and running speed.
Automatic Measurement of the Dependence on Pressure and Temperature of the Mass Density of Drilling Fluids
Authors: Cayeux Eric
Published: March 2021

Drilling fluids are subjected to large variations of pressure and temperature while they are circulated in a well. This span of pressures and temperatures is so large that the mass density of the drilling mud differs from one depth to another. For a precise estimation of the hydrostatic and hydrodynamic pressures, it is therefore important to have a good estimation of the pressure and temperature dependence of the mass density of drilling fluids.

Usually, the mass density of drilling fluids is manually measured with a mud balance. The pressure and temperature dependence of the mass density of the fluid, i.e. its PVT behavior, is then estimated based on the PVT behavior of its components and their relative proportions. However, variations in the composition of the fluid mix and uncertainties on the PVT behavior of each components, may lead to inaccuracies. To circumvent these limitations, an apparatus that measures directly and automatically the PVT behavior of the drilling fluid contained in a pit has been designed.

The setup measures both the mass density and the speed of sound in the fluid at specific conditions of pressure and temperature. From the speed of sound in the liquid mix, it is possible to estimate the adiabatic compressibility. The device also utilizes a heat exchanger from which the thermal conductivity and specific heat capacity of the drilling fluid can be estimated. Combining the specific heat capacity, thermal conductivity and the adiabatic compressibility, the isothermal compressibility can be calculated. By combining measurements made at different conditions of pressure and temperature, a PVT model of the drilling fluid is estimated.

By providing automatically, and on a continuous basis, the actual PVT behavior of drilling fluids, drilling automation systems can gain in precision and at the same time, their configuration can be simplified, therefore making them more accessible to any drilling operation.
Well Control 4.0: Integration of a Transient Model in Automated Well Planning Workflows
Authors: Anfinsen Bjoern-Tore , Mosti Inge , Szemat-Vielma Waldemar
Published: March 2021

Low oil prices are forcing the oil and gas industry to reduce the well construction cost. This calls for new and more efficient technologies and methods. Cost optimization may have negative impact on the risk level as less resources are available. Even with a strong focus on risk and new regulatory requirements, the well control risk level is not decreasing, but rather shows an increase.

A new workflow has therefore been introduced in a collaborative cloud-based well planning system that combines the most advanced transient, multiphase engine with an automated procedure based on drillers method.

The workflow will improve the quality of the well control planning as it will enable a simple way of automatic recalculation when the project context is changing. The data flow and quality control of data will also be improved and result in more up to date planning results. The automation of the process removes a huge amount of manual work that up to know has been required to keep the well control calculations synchronized with the project plan.

New engine features unique to well control modeling like transient temperature and full compositional tracking adds resolution and accuracy to the well control planning results and helps deliver consistency in the results.

The new workflow will deliver well control calculations with better resolution and accuracy with much less effort than what is normal today and should therefore help to reduce risk and cost associated with well planning.
Rotating Control Device Sealing Element Customization for Ultra-Deepwater Gulf of Mexico
Authors: Dow Blaine , Pazziuagan Dexter , Vaczi Ken , Chima Chima , Guidry Jason , Kamps Charley , Gallo Fernando , Ham Jeff , Likki Srinivas
Published: March 2021

As the Managed Pressure Drilling (MPD) systems for deepwater drilling rigs mature, operators are applying the technology on more complex prospects. Wells are encountering higher pressures in deeper water depths, pushing against the boundaries of technical limits not previously encountered.

A prospect in the US Gulf of Mexico required drilling to measured depths exceeding 31000 feet in water deepwater. Under such demanding depth, a non-typical drillstring was required to manage the tensile loading. Typical drill pipe connections on 6 5/8" S-135 tool joints are 8.5" diameter. This drill string would require V-150 landing string, with a 6 5/8" FH tool joint diameter of 8.875". Hard banding would bring the tool joint nominal OD above 9".

The depth of the well and planned string RPM presented risk of casing wear, therefore drillpipe protectors would also be required.

The depth of the reservoir and size of the drillstring meant pipe would need to be stripped out of the well with up to 900 psi backpressure in order to maintain constant bottom hole pressure.

All well challenges were used to determine design specifications for a custom sealing element. The scope of work was to design, validate through finite element analysis, then validate in a test fixture per API16RCD test procedures. On conclusion of the product validation, a land test rig trial, with mock-up of the planned system, including dual sealing elements in the Rotating Control Device (RCD), the required non-rotating drill pipe protectors on the planned drillpipe, was executed. The development schedule from start to finish was compressed to less than 6 months also, targeting completion ahead of the rig's drilling program.

This paper will recount the various phases of the design-build-validate-test effort that went into resolving these technical limits. It will conclude with field results and lessons learned from first deployment.

As operators pursue more challenging deepwater wells, this systematic approach, through alignment of the operator, drilling contractor and MPD technology company, serves as a model to expand the operating envelope of drilling systems, improving safe performance in a cost-effective manner.