Determination of Friction Within a Riser Umbilical

2012 ◽  
Author(s):  
Elise Olsen ◽  
Stian Karlsen ◽  
Lars Jordal ◽  
Kay A. Hansen-Zahl
Keyword(s):  
Oil And Gas ◽  
Electrical Power ◽  
Optical Signal ◽  
Offshore Platforms ◽  
Friction Coefficients ◽  
Friction Forces ◽  
Friction Testing ◽  
The Individual ◽  
Contact Pressures

By combination of elements like hydraulic tubes, electrical and optical signal cables and electrical power cables, umbilicals provide remote control of subsea oil and gas wells. Riser umbilical’s are terminated at offshore platforms or vessels, and will be exposed to tension and bending variations caused by waves and vessel motions. Understanding how forces are transmitted between the elements in an umbilical is vital for correct calculation of the umbilical design life. When umbilicals are exposed to tension and bending, tension will be imposed in the individual elements. The magnitude of tension is governed by the overall tension and bending and also by the lay angles, placement in the cross section and the friction forces between the elements. Some friction coefficients may be found in literature, but not all material combinations, and not for the conditions inside an umbilical. A project was therefore initiated with the aim of developing a friction testing device capable of determining friction coefficients between all elements in environments that are representative for the conditions within an umbilical, i.e.: at various temperatures; in sinusoidal movements, like the bending movements in an umbilical; at representative contact pressures, speeds and temperatures; in various environments, like air and seawater; without crumpling soft elements like synthetic tapes.

scholarly journals Natural Gas

2011 ◽  
Vol 133 (04) ◽  
pp. 52-52
Author(s):  
Rainer Kurz
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Oil And Gas ◽  
Electrical Power ◽  
Offshore Platforms ◽  
Electric Motors ◽  
Turbine Generator ◽  
Associated Gas ◽  
Generator Sets

This article discusses the importance of gas turbines, centrifugal compressors and pumps, and other turbomachines in processes that bring natural gas to the end users. To be useful, the natural gas coming from a large number of small wells has to be gathered. This process requires compression of the gas in several stages, before it is processed in a gas plant, where contaminants and heavier hydrocarbons are stripped from the gas. From the gas plant, the gas is recompressed and fed into a pipeline. In all these compression processes, centrifugal gas compressors driven by industrial gas turbines or electric motors play an important role. Turbomachines are used in a variety of applications for the production of oil and associated gas. For example, gas turbine generator sets often provide electrical power for offshore platforms or remote oil and gas fields. Offshore platforms have a large electrical demand, often requiring multiple large gas turbine generator sets. Similarly, centrifugal gas compressors, driven by gas turbines or by electric motors are the benchmark products to pump gas through pipelines, anywhere in the world.

Viscoelastic Behaviour of Bitumen in Dynamic Control Umbilicals

2014 ◽  
Author(s):  
Elise Olsen ◽  
Kay André Hansen-Zahl ◽  
Stian Karlsen
Keyword(s):  
Cross Section ◽  
Oil And Gas ◽  
Steel Wire ◽  
Optical Signal ◽  
Galvanized Steel ◽  
Offshore Platforms ◽  
Force Transmission ◽  
Steel Wires ◽  
Friction Factors ◽  
Section Analysis

By combination of elements like hydraulic tubes, electrical and optical signal cables and electrical power cables, umbilicals provide remote control of subsea oil and gas wells. For extra tensile strength and outer protection the umbilicals may be armoured by galvanized steel wires. Dynamic umbilicals are terminated at offshore platforms or vessels. They are exposed to tension and bending variations caused by waves and vessel motions. As such a project specific analysis is normally required to verify that a given dynamic umbilical design with all its elements is able to withstand a service life of typically 20–30 years [5]. Understanding how forces are transmitted between the elements in an umbilical is vital for correct calculation of a dynamic umbilical design life. Cross section analysis is therefore performed by a finite element method program specially designed for this purpose. This software takes into account all effects in an umbilical cross section, including friction between elements. For solid elements, commonly known friction factors may be applied. However, for the steel wire armour which is corrosion protected by bitumen, the friction factors may not be valid. The force transmission between the steel wires may not be governed by friction but by the viscoelastic properties of bitumen. In such a case the transition force is not only a function of contact pressure but also of sliding velocity and dimensions. A project was therefore initiated with the aim of describing such force transmission between bitumen and steel wires for typical umbilical conditions. Material testing has included characterization by a controlled stress rheometer and cyclic tensile testing at various temperatures, speeds and geometries. On basis of these tests, a calculation model describing the mechanical behavior of bitumen in cyclic movement is suggested. This model may later be implemented in the umbilical cross section analysis program.

Calculated Behavior and Effective Factors for Bolt Self-Loosening Under a Transverse Cyclic Load Generated by a Linearly Vibrating Washer

2005 ◽  
Author(s):  
Yasuo Fujioka ◽  
Tomotsugu Sakai
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Contact Pressure ◽  
Common Knowledge ◽  
Axial Direction ◽  
Element Analysis ◽  
Friction Coefficients ◽  
Friction Forces ◽  
Contact Surfaces ◽  
The Individual

It is common knowledge that a bolt is apt to loosen due to slippage between the contact surfaces of joined parts. Loosening tests using real parts enable precise scrutiny of real phenomena under the influence of multiple factors such as slip distance, surface roughness, and coefficient friction. However, estimating the influence of the individual factors is very difficult because the friction forces of real contact surfaces are compiled based on variations in friction coefficients, meaning friction is not stable. Therefore, the effects of factors were investigated using Finite Element Analysis (FEA) to control friction coefficients. The procedures were as follows. Assuming a joined structure consisting of a bolt, nut, and washer, bolt axial tension was generated through constant movement of a washer in the bolt’s axial direction, following which the washer was constantly vibrated in one direction transverse to the bolt axis. This vibration generated displacements equivalent to the degree of slippage between the two clamped parts. During vibration, the rotating angles of the bolt and the contact pressure of the threads and bearing surfaces were calculated. The results were as follows. The vibrating displacements of a washer have considerable influence on the rotational loosening of a bolt. In cases where there was only minor displacement of the washer vibrations, the rotational loosening angle rapidly decreased, although the loosening did not cease completely. Therefore, the magnitude of what is called “critical slip” was not confirmed under the conditions of this study. In addition, the friction coefficient has a significant influence on the rotational loosening of a bolt. When the respective friction coefficient values of the threads and bearing surfaces are not balanced, rotational loosening cannot continue. Surface roughness readily affects contact pressure, so it tends to make the contact pressure localized. In particular, high-pressure areas were affected by several projections set on the threads. However, under those conditions the rotational loosening did not differ greatly from the results of the fine surface models subject to the same vibrating amplitude and friction coefficient. Consequently, the localized contact pressure had little evident effect on loosening. Above all, FEA reproduced the loosening of the bolt, and the reference made in this analysis is useful.

ПСИХОЛОГІЧНА ДЕТЕРМІНАЦІЯ ДОМІНУЮЧОГО ІНСТИНКТУ У КОНСТРУКТИВНІЙ САМОРЕАЛІЗАЦІЇ ЖІНОК

1970 ◽  
Vol 6 (1) ◽  
pp. 184-193
Author(s):  
Ольга Віговська
Keyword(s):  
Human Life ◽  
Healthy Children ◽  
Self Disclosure ◽  
Self Identity ◽  
Social Nature ◽  
Self Actualization ◽  
Rational Organization ◽  
The Individual ◽  
Age Range

У статті теоретично обґрунтовано феномен конструктивного самозбереження особистості як ознаки самоактуалізації, розкриття власного потенціалу і побудови перспективи розвитку особистості та емпірично виявлено ознаки психологічної детермінації домінуючого інстинкту у конструктивній самореалізації жінок з різним соціальним статусом. Зазначено, що проблема самозбереження асоціюється з особливостями прояву інстинкту самозбереження людини, але потреби вищого порядку зумовлюють соціальну природу її поведінки, яка локалізована у найвищій точці самореалізації. Теоретично обгрунтовано, що самореалізація визначає тенденцію раціональної організації життя людини та проявляється у її почутті задоволеністю життям. З’ясовано, що психологічну основу конструктивного самозбереження становлять індивідуально-типологічні характеристики людини, які відображають психофізіологічні та психосоціальні резерви самореалізації особистості. Розроблена програма емпіричного дослідження, а також комплекс використаних методів математичної обробки результатів дослідження дає змогу конкретизувати психологічний зміст детермінації домінуючого інстинкту у конструктивній самореалізації жінок вікового діапазону 35-45 років та з різним соціальним статусом. У жінок, які виховують проблемну (хвору) дитину, домінує інстинкт "егофільного типу", що виражається у їх надмірному егоцентризмі і супроводжується низькими показниками самоактуалізації, на відміну від досліджуваних жінок, які виховують здорових дітей і у яких на фоні вираженої тенденції до самоактуалізації домінує базовий інстинкт "дослідницького типу" та "лібертофільного типу". This article theoretically proves constructive phenomenon of self identity as signs of self-disclosure own potential and prospects of development of individual construction. In addition, it empirically showes signs of psychological determination of the dominant instinct in a constructive self-determination of women with different social statuses. It was noted that the issue of self-preservation is associated with the peculiarities of manifestation of self-preservation instinct of man, but it needs higher-order cause social nature of the behavior that is localized at the highest point of self-realization. It theorized that self-realization determines the trend of rational organization of human life and manifests itself in its sense of life satisfaction. It was found that the psychological basis of constructive self-preservation of the individual make individually-typological characteristics of a person that reflect physiological and psychosocial reserves of self-realization. The developed program of empirical research, as well as the methods used complex mathematical processing of results of research allows to specify the content of the psychological determination of the dominant instinct of constructive self-realization а women age range of 35-45 years and with different social status. Women who bring up the problem child dominates the instinct of self-preservation, which is reflected in their excessive self-centeredness, and is accompanied by low levels of self-actualization, as opposed to the study of women who are raising healthy children and that against the backdrop of a pronounced tendency to self-actualization, dominated by basic instinct "research type" and "independent type."

A method of technical diagnostics for offshore structures

1994 ◽  
Vol 16 (2) ◽  
pp. 43-48
Author(s):  
Do Son
Keyword(s):  
Diagnostic Method ◽  
Joint Venture ◽  
Oil And Gas ◽  
Residual Life ◽  
Life Time ◽  
Offshore Structures ◽  
Technical Diagnostics ◽  
Offshore Platforms ◽  
South Vietnam ◽  
Local Destruction

This paper describes the results of measurements and analysis of the parameters, characterizing technical state of offshore platforms in Vietnam Sea. Based on decreasing in time material characteristics because of corrosion and local destruction assessment on residual life time of platforms is given and variants for its repair are recommended. The results allowed to confirm advantage of proposed technical diagnostic method in comparison with others and have been used for oil and gas platform of Joint Venture "Vietsovpetro" in South Vietnam.

Determination of allostatic load dynamics in the assessment of adaptation in temporary workers in the Arctic

2020 ◽  
pp. 547-548
Author(s):  
O. Yu. Atkov ◽  
S. G. Gorokhova
Keyword(s):  
Body Mass Index ◽  
Glucose Level ◽  
Shift Work ◽  
Allostatic Load ◽  
The Arctic ◽  
Temporary Workers ◽  
Short Term ◽  
Short Term Adaptation ◽  
The Individual

The individual dynamics of the allostatic load index was revealed mainly due to changes in the glucose level, body mass index, which makes it applicable for assessing the short-term adaptation to the stay in the conditions of shift work

Methods for assessing territory pollution by oil or petroleum product spills

2020 ◽  
pp. 140-146
Author(s):  
S. I. Chelombitko ◽  
V. V. Piven
Keyword(s):  
Oil And Gas ◽  
Radiant Energy ◽  
Petroleum Products ◽  
Individual Characteristics ◽  
Oil And Gas Fields ◽  
Northern Regions ◽  
Negative Impacts ◽  
The Individual ◽  
Destructive Processes ◽  
Gas Fields

During the development of oil and gas fields and transportation of hydrocarbons, the ecology of regions is subject to various negative impacts. The most severe consequences for the environment are caused by accidental spills of oil or petroleum products, which occur due to through damage to pipelines. Polluted territories are subject to mandatory reclamation in accordance with government regulations and industry regulations. However, despite the measures taken by the administrations of the northern regions to increase the rate of reclamation of damaged territories in recent years, there has been a trend of growth of areas contaminated with hydrocarbons.Various remediation technologies that have been tested in warm and temperate climates are not very effective in regions with permafrost. Pollution of the daytime surface with oil or petroleum products leads to an increase in the absorption of the sun's radiant energy, the growth of the seasonal thaw layer and the development of destructive processes for the territory. To achieve a positive effect as a result of rehabilitation measures, it is necessary to take into account the individual characteristics of the territory and the extent of its pollution.

THE SUBJECT FIELD OF INSTITUTIONAL EDUCATION: THE SENSE AND PROSPECTS OF DEVELOPMENT IN UKRAINE

2020 ◽  
pp. 25-38
Author(s):  
Irina Mordous
Keyword(s):  
Decisive Role ◽  
Subject Field ◽  
National Education ◽  
Progressive Development ◽  
Separate Area ◽  
Economic Transformations ◽  
The Difference ◽  
The Individual ◽  
Political Economic

The development of modern civilization attests to its decisive role in the progressive development of institutions. They identified the difference between Western civilization and the rest of the world. Confirmation of the institutional advantages of the West was its early industrialization. The genesis and formation of institutionalism in its ideological and conceptualmethodological orientation occurs as a process alternative to neoclassic in the context of world heterodoxia, which quickly spread in social science. Highlighting institutional education as a separate area of sociocultural activity is determined by the factor of differentiation of institutional theory as a whole. A feature of institutional education is its orientation toward the individual and his/her transformation into a personality. The content of institutional education is revealed through the analysis of the institution, which includes a set of established customs, traditions, ways of thinking, behavioral stereotypes of individuals and social groups. The dynamics of socio-political, economic transformations in Ukraine requires a review of the foundations of national education and determination of the prospects for its development in the 21st century in the context of institutionalism.

Hydrogeology correction in the gravitational field from satellite data

2018 ◽  
Vol 931 (1) ◽  
pp. 2-7
Author(s):  
V.D. Jushkin ◽  
L.V. Zotov ◽  
O.A. Khrapenko
Keyword(s):  
Gravitational Field ◽  
Oil And Gas ◽  
Repeated Measurements ◽  
Geological Factors ◽  
Grace Satellite ◽  
Gas Pumping ◽  
Acceleration Of Gravity ◽  
Determination Of Parameters ◽  
Gravity Acceleration

The results of repeated measurements of the acceleration of gravity by the Russian absolute ballistic field gravimeter GABL-M on points of oil and gas deposits in the permafrost over a five year period are presented. The changes of gravity acceleration by the absolute gravimeter and GRACE satellite were compared. The results of comparisons of differences gravity acceleration by ballistic gravimeter GABL-M and relative Canadian gravimeters CG5 were [i]shown. The errors in determination of parameters of the gravitational field ballistic gravimeter GABL-M and CG5 gravimeters group were presented. The method of measurement with the gravimeter GABL-M and the method of determining the vertical gradients relative CG5 gravity meters was described. The necessity of introducing corrections of hydrogeology is caused by influence of hydro geological factors on the gravitational field in the permafrost. They are comparable with the values of the field change in the result of gas pumping.

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