bluuebunny/crossref_metadata_2025 huggingface dataset:
HUBUNGAN POLA ASUH ORANGTUA DENGAN KEMANDIRIAN PERSONAL HYGIENE ANAK USIA PRASEKOLAH DI TKIT PERMATA MULIA DESA BANJARAGUNG KECAMATAN PURI KABUPATEN MOJOKERTO
Authors: Vidya Henny , Mustikasari Surya
Published: October 2019

ABSTRACTBackground: Many preschool children are lacking in maintaining their personal hygiene so that this facilitates the occurrence of illness due to lack of maintaining personal hygiene such as worms or diarrhea. This happens because the child is still not able to do personal hygiene independently or still assisted by parents.Purpose: The purpose of the study was to analyze the relationship of parenting with the independence of personal hygiene of preschoolers.Method: The research design is correlational analytic with crossectional approach. The study population is All parents and preschool children in kindergarten Permata Mulia Banjaragung Mojokerto as much as 41 mother and child. The sample was taken by purposive sampling technique as many as 37 respondents. The research variables are parenting as an independent variable and personal hygiene independence as dependent variable. Data were collected by questionnaire instrument of self-care pattern and self-reliance of hygiene, then chi square test.Results: The result of the research shows that 15 of the respondents have adopted the democratic parenting of most of the autonomy of children in the self-supporting category as many as 8 respondents (53.3%). Of the 9 respondents who apply authoritarian parenting system there is 1 child (11.1%) who are independent and parents Applying permissive parenting pattern of most children belonging to self-reliant as many as 7 resondents (53.8%). Chi square test results obtained values Ï = 0, 023 and Î± = 0.05 so that Ï <Î± then there is a Relationship Pattern Parenting with Child Independence Level.Conclusion: There is no best parenting pattern but parents should be able to choose the appropriate parenting pattern in children according to the situation and condition of the child, which is expected later on children have good independence early.Â Key words: Parenting, Independence, Preschool.
THE EFFECT OF MUROTTAL QURâ€™AN ON MENSTRUAL PAIN IN NURSING STUDENT OF UNIVERSITAS NAHDLATUL ULAMA SURABAYA
Authors: Septianingrum Yurike , Hatmanti Nety Mawarda , Fitriasari Andikawati
Published: October 2019

Background: Primary dysmenorrhea is menstrual pain that is found without significant abnormalities in genital organs. More than 50% of women experience primary dysmenorrhea and 15% experience severe pain. Most women never have their primary dysmenorrhea examined by a doctor or midwife, arguing that this is something natural, even if this condition is left unchecked, symptoms of endometriosis will emerge that can affect women's fertility.Objectives: The purpose of this study was to examine the effect of Murottal Qurâ€™an on menstrual pain in nursing students of UNUSA.Method: This study was an experimental research approach with pre-test post-test design at UNUSA. Research subjects of this study was recruited using simple random sampling who was included inclusion criteria. Research subjects in this study was of 32 students who were then divided into two groups, 16 students into intervention group and 16 students into control group. Data were collected by using observation with VAS. Data were analyzed by using sign test and Mann-Whitney U test.Results: The results showed that: 1) Score of VAS in intervention group post testwas less than pre test (p= 0,000), 2) Score of VAS in intervention group was less than control group (p= 0,006). Conclusion: Murottal Qurâ€™an could reduce menstrual pain in nursing student of UNUSA. Further research, is expected that Murottal Qur'an can be compared with music therapy to reduce menstrual pain.Â Keywords: Menstrual pain, Murottal Qurâ€™an, primary dysmenorrhea.
Effectiveness of Genomic Selection by Response to Selection for Winter Wheat Variety Improvement
Authors: Hu Xiaowei , Carver Brett F. , Powers Carol , Yan Liuling , Zhu Lan , Chen Charles
Published: October 2019

Core Ideas

Prediction performance for winter wheat grain yield and end‐use quality traits.

Prediction accuracies evaluated by cross‐validations are significantly overestimated.

Nonparametric algorithms outperform the parametric alternatives in cross‐year predictions.

Strategically designing training population improves response to selection.

Response to selection varies across growing seasons and environments.

Considering the practicality of applying genomic selection (GS) in the line development stage of a hard red winter (HRW) wheat (Triticum aestivum L.) variety development program (VDP), the effectiveness of GS was evaluated by prediction accuracy and by the response to selection across field seasons that demonstrated challenges for crop improvement under significant climate variability. Important breeding targets for wheat improvement in the southern Great Plains of the United States, including grain yield, kernel weight, wheat protein content, and sodium dodecyl sulfate (SDS) sedimentation volume as a rapid test for predicting bread‐making quality, were used to estimate the effectiveness of GS across harvest years from 2014 (drought) to 2016 (normal). In general, nonparametric algorithms reproducing kernel Hilbert space (RKHS) and random forest (RF) produced higher accuracies in both same‐year cross‐validations (CVs) and cross‐year predictions for the purpose of line selection. Further, the stability of GS performance was greatest for SDS sedimentation volume but least for wheat protein content. To ensure long‐term genetic gain, our study on selection response suggested that across this sample of environmental variability, and though there are cases where phenotypic selection (PS) might be still preferred, training conducted under drought or in suboptimal conditions could provide an encouraging prediction outcome when selection decisions were made in normal conditions. However, it is not advisable to use training information collected from a normal season to predict trait performance under drought conditions. Finally, the superiority of response to selection was most evident if the training population (TP) can be optimized.
Stellar Properties of KIC 8736245: An Eclipsing Binary with a Solar-type Star Leaving the Main Sequence
Authors: Fetherolf Tara , Welsh William F. , Orosz Jerome A. , Windmiller Gur , Quinn Samuel N. , Short Donald R. , Kane Stephen R. , Wade Richard A.
Published: October 2019

There is a well-known stellar parameter discrepancy for late K and M dwarfs, in that the observed radii and temperatures are often respectively larger and cooler than predicted by theory by several percent. In an ongoing effort to elucidate this issue, we examine the double-lined Kepler eclipsing binary star system KIC 8736245. We supplement the near-continuous 4 yr Kepler light curve with ground-based multicolor photometry from Mount Laguna Observatory and spectroscopy from the Hobby–Eberly Telescope. The binary has an edge-on, circular 5.07 days orbit with stellar masses equal to 0.987 ± 0.009 and 0.782 ± 0.009 M
⊙ and radii of 1.311 ± 0.006 and 0.804 ± 0.004 R
⊙, respectively, and an estimated age of 7–9 Gyr. We find that the stellar radii are consistent with theoretical models within the uncertainties, whereas the temperature of the secondary star is ∼6% cooler than predicted. An important aspect of this work is that the uncertainties derived from a single epoch (individual night of observations) underestimate the overall system parameter uncertainties due to the effect of the 1%–4% fluctuations caused by stellar activity. Our error estimates come from the spread in parameters measured at eight epochs. From the periodicities in the light curve and from the eclipse times, we measure candidate spin periods to be approximately 4.98 and 5.87 days for the primary and secondary star. Surprisingly, these imply super- and subsynchronous rotation compared to the orbital period. Thus KIC 8736245 serves as an interesting case study for the exchange of angular momentum and general stellar astrophysics as stars in binaries evolve off the main sequence.
Dynamical Masses for the Triple System HD 28363 in the Hyades Cluster
Authors: Torres Guillermo , Stefanik Robert P. , Latham David W.
Published: October 2019

The star HD 28363 in the Hyades cluster has been known for over a century as a visual binary with a period of 40 yr. The secondary is, in turn, a single-lined spectroscopic binary with a 21 day period. Here we report extensive spectroscopic monitoring of this hierarchical triple system that reveals the spectral lines of the third star for the first time. Combined with astrometric information, this makes it possible to determine the dynamical masses of all three stars. Only six other binaries in the Hyades have had their individual component masses determined dynamically. We infer the properties of the system by combining our radial-velocity measurements with visual observations, lunar occultation measurements, and with proper motions from the Hipparcos and Gaia missions that provide a constraint on the astrometric acceleration. We derive a mass of

for the visual primary, and 1.210 ± 0.021 and 0.781 ± 0.014 M
☉ for the other two stars. These measurements along with those for the other six systems establish an empirical mass–luminosity relation in the Hyades that is in broad agreement with current models of stellar evolution for the known age and chemical composition of the cluster.
Spectroscopic Constraints on the Cross-sectional Asymmetry and Expansion of Active Region Loops
Authors: Kucera T. A. , Young P. R. , Klimchuk J. A. , DeForest C. E.
Published: October 2019

We explore the constraints that can be placed on the dimensions of coronal loops out of the plane of the sky by utilizing spectroscopic observations from the Hinode/EUV Imaging Spectrometer (EIS). The usual assumption is that loop cross sections are circular. Changes in intensity are assumed to be the result of changing density, filling factor, and/or point of view. In this work we instead focus on the possibility that the loop dimensions may be changing along the line of sight while the filling factor remains constant. We apply these ideas to two warm (

) loops observed by EIS in Active Region 11150 on 2011 February 6 with supporting observations from Solar Dynamics Observatory's Atmospheric Imaging Assembly and the Solar TErrestrial RElations Observatory-A's Extreme Ultraviolet Imager. Our results are generally consistent with nonexpanding loops but could also allow linear expansions of up to a factor of 2.5 along a 40 Mm section of one loop and up to a factor of 3.9 in another loop, both under the assumption that the filling factor is constant along the loop. Expansions in the plane of the sky over the same sections of the loops are 1.5 or less. For a filling factor of 1, the results of the analysis are consistent with circular cross sections but also with aspect ratios of 2 or greater. Count rate statistics are an important part of the uncertainties, but the results are also significantly dependent on radiometric calibration of EIS and the selection of the loop backgrounds.
Proper Motions of Stellar Streams Discovered in the Dark Energy Survey
Authors: Shipp N. , Li T. S. , Pace A. B. , Erkal D. , Drlica-Wagner A. , Yanny B. , Belokurov V. , Wester W. , Koposov S. E. , Kuehn K. , Lewis G. F. , Simpson J. D. , Wan Z. , Zucker D. B. , Martell S. L. , Wang M. Y. ,   (S5 Collaboration)
Published: October 2019

We cross-match high-precision astrometric data from Gaia DR2 with accurate multiband photometry from the Dark Energy Survey (DES) DR1 to confidently measure proper motions for nine stellar streams in the DES footprint: Aliqa Uma, ATLAS, Chenab, Elqui, Indus, Jhelum, Phoenix, Tucana III, and Turranburra. We determine low-confidence proper-motion measurements for four additional stellar streams: Ravi, Wambelong, Willka Yaku, and Turbio. We find evidence for a misalignment between stream tracks and the systemic proper motion of streams that may suggest a systematic gravitational influence from the Large Magellanic Cloud (LMC). These proper motions, when combined with radial velocity measurements, will allow for detailed orbit modeling that can be used to constrain properties of the LMC and its effect on nearby streams, as well as global properties of the Milky Way’s gravitational potential.
Difficultés économiques et transformation des unions à Kinshasa
Authors: Nappa Jocelyn , Schoumaker Bruno , Phongi Albert , Flahaux Marie-Laurence
Published: October 2019

Kinshasa, mégapole de près de 10 millions d’habitants, a connu d’importantes transformations économiques, sociales et démographiques au cours de ces dernières décennies. Cet article analyse les transformations des pratiques matrimoniales dans un contexte de détérioration des conditions économiques et de pénurie d’emplois. Les données de l’enquête du projet Mafe (Migration entre l’Afrique et l’Europe), réalisée en 2009 à Kinshasa, mettent en évidence le recul des premières unions et des mariages, pour les hommes comme pour les femmes. Des analyses biographiques montrent que les difficultés économiques diminuent les chances de se marier. Les effets des facteurs économiques sont plus prononcés pour les hommes que pour les femmes, et l’écart dans les chances de mariage entre les hommes qui disposent de ressources et ceux qui en ont moins s’est lui aussi accentué au fil du temps. Le coût croissant du mariage, qui repose en grande partie sur le futur marié et sa famille, ainsi que les difficultés croissantes pour répondre à ces exigences financières, expliquent en partie ces résultats. Dans ce contexte, les unions libres et les naissances hors mariage se développent et tendent à se substituer aux mariages.
Comparaison de survie de cohortes entre les pays d’Europe centrale et orientale et les pays à longévité élevée
Authors: Nepomuceno Marília R. , Canudas-Romo Vladimir
Published: October 2019

Malgré les progrès récents et notables de la survie en Europe centrale et orientale, cette région reste loin derrière les populations des pays les plus développés. En se plaçant dans une perspective de cohorte pour étudier l’écart de mortalité entre les pays d’Europe centrale et orientale et un groupe de pays dont la longévité actuelle est élevée, cet article montre comment la survie des cohortes contribue au différentiel de mortalité global. La décomposition de la « durée de vie moyenne transversale sur données tronquées » permet d’isoler les contributions des âges et des cohortes à l’écart de mortalité. À partir de données concernant la période 1959-2013 et issues de la Base de données sur la mortalité humaine, on constate que, par rapport à leurs homologues vivant dans des pays à longévité élevée, la plupart des cohortes d’Europe centrale et orientale nées en 1959 et après ont des taux de mortalité plus élevés, de la naissance à l’âge atteint en 2013. Toutefois, certaines cohortes d’Europe centrale et orientale bénéficient d’un avantage de survie. C’est par exemple le cas des cohortes tchèques nées au début des années 1960 et des cohortes nées dans des pays de l’ex-URSS durant cette même décennie.
Pellaea calomelanos (Pteridaceae) en Cataluña: es realmente una disyunción ancestral?
Authors: Vitales D. , García-Fernández A. , Garnatje T. , Vallès J. , Font J. , Robert Y. , Vigo J.
Published: October 2019

Pellaea calomelanos es una especie que fue descubierta en África y cuya área de distribución se ha ido ampliando más recientemente a Asia y a una única localidad europea, que comprende tres poblaciones, en Cataluña. El hecho de pertenecer a los helechos y de presentar esta distribución disyunta alimentaron la idea de una especie relicta resultante de distribución amplia en tiempos remotos. Los valores 2C van desde 16,45 pg para el individuo de la Isla de la Reunión hasta 17,40 pg para la población de Boadella (Cataluña). Aunque existe una cierta variabilidad, no se han encontrado diferencias estadísticamente significativas entre ellos. El análisis filogenético revela un clado bien soportado que agrupa a todos los individuos de las diferentes poblaciones de P. calomelanos pero sin ningún tipo de resolución interna. Los resultados del presente trabajo, basado en medidas de cantidad de ADN nuclear y en secuencias de dos regiones del ADN cloroplástico, junto con las características de su hábitat, permiten a los autores hipotetizar sobre una colonización reciente del continente europeo por esta especie.
Cutting Force Changes during One Cut in End Milling with a Throw-Away Insert - Difference between Up-Cut and Down-Cut –
Authors: Matsuda Kota , Tanaka Ryutaro , Sekiya Katsuhiko , Yamada Keiji
Published: October 2019

In this study, the transition of cutting force in the tangential and radial direction during one cut was investigated in milling of AISI-1045, AISI-304, and Ti-6Al-4V with a TiN coated carbide throw-away insert. In the case of 1045 and Ti-6Al-4V, there was not obvious difference in tangential forces between up-cut and down-cut. However, up-cut showed larger radial force than down-cut in any material. In down-cut, tangential force showed almost the same regardless of radial depth of cut. 304 and Ti-6Al-4V caused larger radial force with the increase of radial depth of cut at the same cut chip thickness.
Analytical Computing Stresses and Strains in Single Point Incremental Forming
Authors: Dien Le Khanh , Tan Le Khanh , Nguyen Van Thanh , Nguyen Huy Bich , Nguyen Thanh Nam
Published: October 2019

Nowadays, Single Point Incremental Forming (SPIF) has become popular for metal sheet forming technology in industry in many advanced countries. In the recent decade, many relative studies have concentrated on this new technology of forming sheet by Finite Element Method (FEM) as well as by empirical way. There were very rare studies by pure analytical computing and P.A.F. Martins et al. under a title “Theory of single point incremental forming” performed almost all these researches were based on the analytical framework of SPIF in 2008. After careful studying on this research, we found out its light illogical result: the stresses inside of a random point in the workpiece sheet are constant and not related to the coordinate of the formed point of the sheet. Therefore, it cannot explain the mechanism of rupture and tear of the sheet that is really a serious restriction of the SPIF technology nowadays. This paper dedicates to suggest a new version of pure analytical computing the normal stresses at a random formed point in the sheet that could explain the tear mechanism and a FEM simulation was also carried out also to prove the conviction of the recommended formula.
Surface Roughening of Silicon Wafer Solar Cell by Using ECDM Method
Authors: Tsui Hai Ping , Chang Kuang Hua , Yan Biing Hwa
Published: October 2019

This research proposes surface roughening of silicon wafer solar cell by electrochemical discharge machining (ECDM). The stainless steel was used as negative electrode. The graphite was used as the positive electrode acting as the auxiliary electrode. The potassium hydroxide was used as the electrolyte. The processing parameters include the machining voltage, the processing time, the machining gap, the electrolyte concentration, the additive agent concentration, pulse frequency and duty factor, etc. The result of experiments reveals that appropriate concentrations of ethanol can expand the size of the pores and enhance surface roughening effect. The appropriate processing parameters are a machining gap of 200μm, voltage of 48V, concentration of potassium hydroxide of 3M, concentration of ethanol of 4%. The electrochemical discharge machined surface roughness was increased from 0.417μm to 0.915μm using one minute processing time. The average reflectance rate of the textured surface was decreased from 29.6% to 12.7%. This study reveals that ECDM method has the advantage of short processing time and can generate a higher surface roughness and the porous structure.
Regulatory Design Assessment of Cold Bonded Fasteners
Authors: Quéméré Marie-Odette , Court Jean-Philippe , Montaufray Pierre , Errotabehere Xabier , Noury Philippe , Zakariyya Ksenia , Martinsen Olin Henning
Published: October 2019

An increasing number of Brazilian floating platform units are currently entering a mature age, inducing numerous asset integrity issues. As corrosion damages FPSOs’ hull structures and outfitting, repairs and/or modifications have to be performed in explosive environment. Those features create important operational challenges, both in terms of safety and production continuity, when hot work techniques are to be used. This is the reason why Cold Pad has developed a cold work technique based on a heavy duty, bonded, mechanical fastener called C-CLAW™. On FPSOs, this novel solution allows today to repair primarily corroded outfitting like handrails, pipe supports, cable trays, electrical boxes and the like. Cold Pad and DNV GL are working together on a design philosophy, a regulatory approach, and a validation programme based on the DNVGL-ST-C501 and the so-called load and resistance factor design (LRFD) format. The article focuses on the application of the regulatory approach for the demonstration of the capacity and reliability of these fasteners. The strength of the bondline and steel fastener components, with their multiple failure mechanisms, are addressed and mainly supported by short-term test results.

The article details the main challenges of that new design approach throughout the service life of bonded fasteners, and includes results and findings related to e.g. strength, susceptibility to temperature, and allowable short-term mechanical capacities based on regulatory safety factors. It also provides the early conclusions in terms of application on FPSOs and recommendations regarding fire hazards. The novelty of these bonded mechanical fastener lies, firstly in the industrial product itself, and secondly in the application of one of the most recognized offshore standards for composite components to derive its regulatory mechanical rated capacity.
An Analytical Method to Combine Environmental Attributes to Generate the Matrix of Importance of Environmental Impacts for the Decommissioning of Subsea Installations in Brazil
Authors: De Oliveira Luiz Fernando Seixas , Schaffel Silvia Blajberg , Do Amaral Netto Joaquim Domingues
Published: October 2019

A new method developed to evaluate the performance measure of some sub-criteria of the environmental criterion in a Comparative Assessment of various options of the decommissioning of subsea installations in Brazil is presented. The method is based on an adaptation of that proposed by IBAMA in Technical Note N°. 10/2012 (TN 10) used for assessment of environmental impacts required for the licensing of offshore activities in Brazil. By requirement of the Comparative Assessment methodology, there is a need for a numerical evaluation that allows comparing the performance of one alternative over the others. An analytical method was developed based on the combination of environmental attributes that contribute for the magnitude of the impacts (frequency, intensity, extension and duration) and sensitivity of the environmental factors affected (relevance, resilience and reversibility). The importance of the impacts is given by the combination of the environmental sensitivity with the magnitude of the impacts, in the called "Environmental Impact Importance Score Matrix". The proposed method provides a performance measure that allows comparing and prioritizing each decommissioning option according to the proposed criteria. It reduces the subjectivity in assessing the importance of the environmental impacts and provides greater transparency and traceability in the assessment of the impacts. As an example, the proposed method is applied for the decommissioning of a rigid pipeline between two platforms in Campos Basin, where the considered decommissioning options are: (a) complete removal by cut and lift and (b) leave in situ. For this particular case, the assessment of the proposed environmental sub-criteria revealed that Option (b) was the preferred option with respect to the impacts on marine and onshore environment.
Technology Intelligence Analysis Based on Document Embedding Techniques for Oil and Gas Domain
Authors: Cordeiro Fábio Corrêa , Gomes Diogo da Silva Magalhães , Gomes Flávio Antônio Machado , Texeira Renata Cristina
Published: October 2019

Objectives/Scope

we propose a methodology based on document embedding techniques for applying Technology Intelligence Analysis in Oil and Gas (O&G) domain. We build a specialized corpus in O&G domain and train a Vector Space Model (VSM) to represent each document as a vector, in such a way that the distance between two vectors captures their semantic similarity. We explore different analysis on this VSM to infer relations between documents, in order to obtain new insights in a strategic context.

Methods Procedures

this proposed methodology is based on Natural Language Processing (NLP) techniques to obtain strategic insights in a technology intelligence analysis scenario. It consists on generating a vector space model (VSM) induced from a domain-specific Oil and Gas corpus, composed of thousands of scientific articles collected from the Elsevier online database. We explore an approach to represent different entities - such as articles, authors and keywords - in the same vector space, making it possible to correlate them and infer relations of similarity based on their cosine distance. An evaluation metric is also provided in order to assist the training process and hyperparameters optimization.

Results, Observations, Conclusions

Oil and Gas highly technical vocabulary represents a challenge to NLP applications, in which some terms may assume a completely different meaning from the general - context domain. In this scenario, gathering an Oil and Gas corpus and training specialized vector space models for this specific domain allows increasing the quality in Technology Intelligence Analysis. The most significant finding is that we were able to explicit the semantic relationships between different entities of interest in the same VSM, also linking these relationships together with some additional metadata. An interesting application is to compare the publications of authors affiliated to two or more O&G companies at a given time. These non-trivial correlations are important to gain strategic insights considering a Technology Intelligence Analysis scenario.

Novel/Additive Information

the novelty of this proposed methodology is the possibility of exploring new insights when correlating different entities in a technology intelligence scenario for the Oil and Gas domain, using a simple yet efficient approach based on document embedding techniques. This method applies some advanced NLP techniques to quickly process more than a hundred thousand documents in a few seconds, without requiring complex hardware resources, which would be impractical using traditional techniques.
Life Extension of Offshore Structure Using Machine Learning
Authors: Bhowmik Subrata
Published: October 2019

The objective of the paper is to demonstrate the Machine Learning (ML) based Structural Integrity Management (SIM) Methodology and its application for the life extension of the offshore structure. This paper also illustrates how the sensor data are used to generate an ML based predictive model and how it will be used to minimise the inspection cost without using the traditional Risk Based Inspection(RBI) methodology. Structural assessment, real-time monitoring and predictive maintenance are the three main aspects of the life extension process for the offshore structure. Usually, the structures are designed for a fixed design life, but during life extension process it is assessed through FE analysis and various inspection methods whether the structure will have adequate fatigue life for another 5-10 year. But running fatigue analysis is computationally expensive as well as inspection also increase the operational cost. Sensors are installed on the offshore structure, and the stress, acceleration, wave, current etc. are measured and transmitted through wired or wireless sensor network and stored in cloud computing. This data is used for predicting the new wave and current data for 1 and 10-year return period. The acceleration data is used to get the modal frequencies and calibrate the FE model. Also, the measured stress value is compared with the FE model generated stress value, and the FE model is further calibrated.

Machine Learning Algorithm (Recurrent Neural Network) is used to generate the predictive maintenance schedule based on the data-driven fatigue prediction model created from the measurement data. The case study shows the life extension of the offshore jacket structure with proposed machine learning based life extension methodology.

The data-driven fatigue predictive model generates the remaining fatigue life, and it is compared with the fatigue life calculated from the FE model. It shows a good match and within 5-10% inaccuracy limit. The predictive maintenance schedule is developed based on the remaining fatigue life. ML-based model significantly reduces the computational cost as well as the real-time data also improves the fatigue life calculation accuracy. Hence, though predictive maintenance, the overall operational cost will be reduced significantly.
Salt Creeping Analysis on Deepwater Wells Submitted to Cooling Operations on Trapped Annular
Authors: Agostini Cristiano Eduardo , Almeida Luiz Felippe Medeiros , Júnior Nelson Moreira , Magalhães Mateus Dias , Roman Roger Savoldi , Schnitzler Eduardo , Silva Alan Pinheiro
Published: October 2019

This paper presents the finite element analysis of salt-creep behavior on deepwater wells with trapped annulus, considering cooling effects caused by injection operations. In addition, this effect was considered coupled with salt-creep behavior and its influence on casing collapse design under transient and steady state well operation. The scenarios of injection flow rate and temperature profile were analyzed using the coupled approach, for salt creeping and thermal trapped annulus. The wellbore profile is a typical Pre Salt Brazilian Offshore, where rock salt layer is confined under two casing shoes. The injection wells operation results in a pressure decrease in a confined annulus due to thermal cooling between casing and salt formation. Due to this pressure drop on the trapped annulus, the salt creeping behavior tends to increase, and proper casing stress verification must be done. The finite elements analysis for salt creeping was modeled using commercial finite elements software package, and thermal profile for transient and steady state injection was obtained using thermal casing design software. The coupled effects were evaluated using commercial casing design software. Preliminary studies have shown that there is a great influence on the salt creeping response on confined annulus when subjected to a pressure decrease due to thermal cooling on trapped annulus, caused by water injection operation. It is observed that there is a growth of the confined annular pressure due to salt creeping effects and that there is an acceleration in this phenomenon. The analysis also shows that casing collapse safety margin is time dependent considering a given operation. After well shutdown, the natural heating of the confined annulus occurs due to geothermal effects, and this pressure is added to the trapped annulus, increasing the pressure of trapped annulus. The final pressure is the sum of the salt pressure build up accelerated by the cooling steady state regime and geothermal pressure build up, during shutdown. The worst case scenario could be during restart the well injection, in that way, this kind of situation must be analyzed, so that it does not lead to critical situations on the casing design. Historically, according to literature review, only the annular pressure build up with production heating is analyzed. This work is a novel approach where annular pressure drop off, caused by cooling operations, was investigated including coupled salt-creeping and thermal phenomenon.
Carbonate Porosity and Permeability from Sonic Log
Authors: e Silva Fernando Gomes de Mello , Beneduzi Carlos Francisco , Nassau Gabriel Feres , Rossi Tiago de Bittencourt
Published: October 2019

The main goal of this work was to estimate carbonate porosity from sonic log S-wave slowness measurement, practically insensitive to fluid effect. Methodology is empirical and had already been successfully tested in sandstones (Silva and Beneduzi (2018)).

Oolitic carbonate reservoir log data were used and porosity is in good agreement with lab data. Small deviations were observed in more heterogeneous carbonate systems mainly composed by stromatolites or bivalves, being interpreted as porous geometry influence.

Compressional velocity deviation log methodology (Eberli et al., 2003) is currently used to identify porosity type in carbonates. The present rock physics model used to estimate porosity allows to define shear velocity deviations. Combination between Vp (P-wave velocity) and Vs (S-wave velocity) deviation (Vp/Vs deviation log) shows good compatibility with flow zones.

A significant linear correlation was observed between new deviation curve and the lab values, allowing calculate permeability for the entire well. Results are in good agreement with NMR log permeability. New method brings up important reservoir petrophysical information. Moreover, the results can give a very important technical support in the early stages of well evaluation.
Increasing the Attractiveness of Phased Field Development: De-Risk Reservoir Uncertainty with Efficient Field Development Solution
Authors: Basu Shiladitya , Bhaumik Tirtharaj
Published: October 2019

Phased Field Development (PFD) is a well-known method to mitigate reservoir uncertainty. However, by its very nature a PFD lowers the Net Present Value (NPV) of the project compared to a Full Field Development (FFD). In this work, multiple scenarios are investigated to increase the attractiveness of PFD vis-a-vis FFD. The most promising concepts are identified and their key financial characteristics are studied with a view to providing a roadmap that can assist in efficient planning of future deepwater field developments.

Annual cash flows along with revenue and profit margins are estimated and compared for the two options for a potential deepwater field development in US Gulf of Mexico.
MSE-Index: A New Concept of Energy Management to Control Salt Creep and Optimize Drilling Operations in Extensive Salt Intervals
Authors: Pinto Constantino N , Lima Angelo P , Knabe Steven P
Published: October 2019

Exploratory and appraisal drilling in extensive salt intervals poses a severe challenge in terms of nonproductive time (NPT) and associated costs. This paper introduces the concept of the mechanical specific energy (MSE) index for creep control in real time. This index is fundamental to leveraging an understanding of MSE behavior while drilling and managing an effective equivalent circulating density (ECD) plan.

An ECD management plan must be restricted to a salt creep operational window (SCOW) between a lower limit and a higher ECD limit. The higher limit is based on a leakoff test (LOT) or formation integrity test (FIT). The challenge in defining a SCOW is therefore assessing the lower limit because its variations with depth determine the minimum ECD. A retrospective analysis of a Brazilian presalt exploration campaign determined that, while drilling in salt layers, a direct relationship exists between creep effects (caused by insufficient ECD to stabilize the wellbore) and the behavior of applied MSE (MSEa) with depth. This relationship was analyzed to create an MSE index as a probability vs. depth matrix to help estimate the lower ECD limit during predrill planning and to make necessary adjustments to operational parameters while drilling.

This paper presents two salt creep control cases in the Brazilian pre-salt.

In the first case, drilling occurred in an extremely soluble salt environment with a high tendency to creep and cause stuck pipe. Geomechanical analysis in real time helped to control creep in the entire drilled salt interval. This analysis resulted in exceptional performance in a critically important section by eliminating five of the ten planned operational days and managing ECD within the predicted SCOW by a good safety margin.

Conversely, situations occur in both thin post-salt depositional environments and large shallow and evaporitic sections in which the SCOW does not permit creep control with a good safety margin. The second case presents specific solutions for this complex scenario, which is characterized by low LOTs/FITs, causing lost circulation and stuck pipe. In response, the authors propose that the industry adopt a new concept, the MSE index, to support the SCOW design in predrill planning and real-time operations.

The aim of this paper is to help reduce operational days, drilling risks, and costs in drilling environments with complex geopressure variations and narrow pore pressure windows by providing techniques to maintain pressure control, reduce NPT, decrease the potential for mud losses, and reduce stuck pipe events.
Comparative Analysis of Permanent P & A Requirements and Consequences in Terms of Leakage - A Case Study
Authors: Beltrán-Jiménez Katherine , Lohne Hans Petter , Ford Eric Patrick , Skadsem Hans Joakim , Lourenco de Souza Marcelo Igor , Arild Øystein
Published: October 2019

In South America, the discussion regarding permanent plug and abandonment (P&A) at the end of the useful life of the fields is relatively recent, but it has become increasingly important due to the maturity of certain oil fields. In Brazil, for example, the Campos, Santos and Espirito Santos Basins alone have 350 temporarily abandoned wells that should be abandoned in the coming decade. The long-term integrity of the wells once plugged and abandoned is, however, not yet considered. There is a need to perform assessments of the risk of leakage, reviewing both the probability of failure of the well barrier elements and the possible magnitude of leakage rates should one or more well barriers be compromised. This article presents a quantitative risk assessment framework that can be used to analyze the probability of barrier failure and potential consequences in terms of leakage rates. Data of a real well is used to quantify the leakage rates after a hypothetic permanent plug and abandonment operation using as reference the plug and abandonment requirements in Brazil and Norway. For both cases, the leakage paths between the reservoir and the wellhead are studied and include: the leakage through bulk cement, cracks/fractures in well barriers elements (impermeable formations, plug, and annular cement) and the presence of micro-annuli. A stochastic framework, using Monte Carlo simulations, is used to propagate uncertainty, yielding probability distributions for leakage rates. As the leakage rates are also a function of time, an analysis considering time-dependent factors such as reservoir re-pressurization is also included. The leakage scenarios for the well is presented considering the P&A requirements included in resolution N 46 (issued by the National Agency of Petroleum, Natural Gas and Biofuels (ANP) in 2016), the guidelines for the abandonment of the Brazilian Petroleum Gas and Biofuels Institute (IBP) and NORSOK D-010. Some requirements, such as plug length and barrier verification methods, are different between these two guidelines. The results are discussed in relation to the P & A requirements and the effect on the total leakage rates for each well case.
Optimization of Advanced Dual Refrigerant Expansion Cycle for Liquefaction
Authors: Kim Minki , Ryu Sijin , Lee Jongchul , Lee Donghun , Kim Mungyu , Park Hyunki , Kim Hyobin , Lee Kihwan , Kim Taeyun
Published: October 2019

This paper shows the sequential search algorithm that makes it possible to find the optimum operating conditions of Advanced Dual Refrigerant Expansion Cycle that is used for LNG liquefaction process. The operating conditions are key parameters in determining the overall liquefaction efficiency of system, so it is the core process to find out these optimized key parameters in LNG industries. The steps of this method are as follows. 1) Defining input variables based on understanding of liquefaction cycle and thermodynamics. 2) Setting simulation to apply the sequential search algorithm. 3) Searching sequentially several local optimum points between the upper and lower limits of several input variables considering minimum/average efficiencies and the number of points satisfied with minimum approach 4) Repeat step 3) with narrower ranges and step sizes of each input variable based on previous results. 5) Get the global (final) optimum point considering final results and realistic operation. The operating conditions of Advanced Dual Refrigerant Expansion Cycle are eventually optimized with the best overall liquefaction efficiency of system by using the sequential search method. It is directly related to economical effect in terms of the high production rate against supply power, small size of equipment and the associated pipe lines, simple system layout and so on. During searching, several local optimum points of the operating conditions can be recorded in order to compare the liquefaction efficiencies at each of points by using this method. It serves as the objective evidence to understand trends of the efficiencies calculated from variable inputs. In addition, this method can provide a variety of selecting the main equipment such as compressor, expander, heat exchanger and so on because it is possible to identify several local optimum points have similar efficiencies. This new sequential search method can be applied for the optimization of existing other gas expansion liquefaction cycles and the mixed refrigerant (MR) LNG liquefaction cycles by making adjustments to input variables e.g. MR compositions can be available input variables as well in case of MR cycles.
Robust Artificial Lift Solution for Ultra-Deepwater Heavy Oil Atlanta Field
Authors: Cavalcante Barbara Ferreira , Rocha Paulo Sergio , Santos Marcelo Paulino , Tavares Alexandre , Neto Salvador Jose Alves , Matos Joao Siqueira , Marsili Marcelo Danemberg
Published: October 2019

Most of the artificial lift strategies in deepwater environments require sophisticated and robust solutions, aiming to improve the system's run life and reliability. Due to that, oil companies choose only trustable technology and field-proven solutions for artificial lift design. This is the case of Atlanta Field's artificial lift project, with electrical submersible pumps (ESP) installed at more than 1,550 m water depth, to produce heavy oil.

For Atlanta Field, the ESP must handle high viscous oil and emulsions at high flow rates to be economically feasible. To achieve this goal, it was deployed one of the most powerful ESP in the world with 1,550 HP induction motor and more than one hundred pump stages into the well. This is the largest ESP in-well successfully installed in Brazil.

The artificial lift strategy adopted for Atlanta Field was an in-well ESP as primary method and an artificial lift skid (ALS) installed on the seabed for back-up. When the primary method fails, there is no in-well ESP replacement, because of high costs involved with workover and the back-up system becomes the main one. When the back-up system fails, the replacement of the pumping module is done by an AHTS equipped with active compensate crane for subsea installation. In this way, replacement costs are much lower than those needed to replace pumps inside the wells.

So far, this artificial lift strategy has proven to be reliable and project results will be discussed in this paper. Strategies to optimize production will be addressed and observations regarding free gas ESP pumping will be made.

After a period producing, the in-well ESP have failed, and the ALS became the main system to produce both wells, as planned. The project faced some challenges with ALS operation, since there was an expressive flow restriction in the in-well ESP. Experimental tests were permeformed to better determine the pressure drop caused by the flow through the pump stages and to propose a solution to the production restriction. By-pass valves were adopted in the project to avoid the mentioned issue.

The well ATL-4 was drilled in March 2019. As this operation requires a drill ship, it was decided to perform workovers in wells ATL-2 and ATL-3 to replace the in-well ESPs and install the by-pass valves in the well's production string.
New Strategies for Cost Reduction with Depth Correlation in Deepwater Wells
Authors: Pereira Yerecê Da Silva , Scudino Borges Raphael Pereira , Schnitzler Eduardo , Roman Roger Savoldi , Paraski Henrique Von , Destri Alice Claussen , Destri João Almeida , Gozzi Danilo Signorini , Baumann Carlos , Merino Carlos
Published: October 2019

Some completion operation steps, such as perforation and packer seating, require that the degree of uncertainty be limited. The main correlation methods used today are based on tally accuracy, tagging a known element in the well or using wireline gamma ray readings. This paper discusses the development of four alternative depth correlation techniques that aim at avoiding the use of wireline in completion and well testing scenarios. All these methods were implemented in field jobs and demonstrated their efficiency with lower operational cost, higher operational safety and acceptable margin of error for the target job. Two methods are based on gamma ray readings and to send data to surface they use logging while drilling (LWD) and wireless telemetry. Target applications for these two methods are tubing-conveyed perforation (TCP) and well testing operations. The other two methods use casing internal diameter (ID) changes at known depths to determine string depth. One uses a rigid hole-opener to tag a crossover or the top of a liner and the other uses the pressure drop produced by a packer entering into a well section with smaller ID. The main advantages of these new depth correlation techniques are rig time savings and greater operational safety by reducing personnel exposure to dangerous operations.