GOST R 54918-2012

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  ГОСТ Р 54918-2012

GOST R 54918−2012 (ISO/TR 10400:2007) Pipe casing, tubing, drill pipe and pipelines of the oil and gas industry. Formulas and calculation properties

GOST R 54918−2012
(ISO/TR 10400:2007)

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

CASING, TUBING, DRILL PIPE AND PIPELINES OF THE OIL AND GAS INDUSTRY

Formulas and calculation properties

Casing, tubing, drill and line pipes for petroleum and natural gas industries. Equations and calculation of properties

OKS 75.180.10
OKP 13 2100
13 2700
13 2400
13 9000

Date of introduction 2013−10−01

Preface

1 PREPARED by Subcommittee SC 7 «Pipe threaded oil country» of the Technical Committee for standardization TC 357 «Steel and cast iron pipes and cylinders» based on the authentic translation into Russian language specified in paragraph 4 of the international standard, which is done by «Specialized translation company «Interservice"

2 SUBMITTED by the Technical Committee for standardization TC 357 «Steel and cast iron pipes and cylinders"

3 APPROVED AND put INTO EFFECT by the Federal Agency for technical regulation and Metrology of June 27, 2012 N 123-St

4 this standard is modified in relation to the international standard ISO/10400:2007* «the Industry of oil and gas. Formulas and calculations to determine characteristics of the casing, tubing, drill pipe and pipes used as casing or tubing» (ISO/TR 10400:2007 «Petroleum and natural gas industries — Equation and calculation for the properties of casing, tubing, drill pipe and line pipe used as casing or tubing») by:

— change individual words (phrases, meanings, indicators, links) highlighted in the text of this standard in italics*;

— changes of individual structural elements (paragraphs, subparagraphs, paragraphs, terminology articles, tables and figures) highlighted in the text of this standard in italics, and bold vertical line located on the margins of this text**;

— any additional words (phrases, meanings, indicators, links) highlighted in the text of this standard, bold, italic*;

— any additional structural elements (sections, paragraphs, subparagraphs, paragraphs, terminology articles, tables and figures) highlighted in the text of this standard the bold vertical line located on the margins of this text**;

— changing the structure to conform to rules established by vhost R 1.5 (subsections 4.2 and 4.3). Comparison of the structure of this standard with the structure of this international standard are given in Appendix YES.
________________
* In the original paper designation and number of standards and normative documents in «2 Normative references»; «3 Terms and definitions», «10 calculation of the strength of the couplings under pressure», «11.1 General» «App DB» are in regular font; the text is marked by the sign «» is shown in bold italics, the rest on the text in italics;
** The electronic version vertical line located on the margins of the text. — Note the manufacturer’s database.

The name of this standard changed with respect to names specified international standard for compliance with GOST R 1.5 (subsection 3.5).

In applying this standard it is recommended to use instead of the referenced international standards corresponding national standards of the Russian Federation and interstate standards, details of which are given in Appendix DB

5 INTRODUCED FOR THE FIRST TIME


Application rules of this standard are established in GOST R 1.0−2012 (section 8). Information about the changes to this standard is published in the annual (as of January 1 of the current year) reference index «National standards» and the official text changes and amendments — in monthly information index «National standards». In case of revision (replacement) or cancellation of this standard a notification will be published in the upcoming issue of the monthly information index «National standards». Relevant information, notification and lyrics are also posted in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet (gost.ru)

Introduction

This standard was developed with the aim of switching the Russian industry to the world practice of calculation of the characteristics of casing, tubing, drill pipe and pipes for pipelines that are performed according to the international standard ISO/10400, elimination of barriers to trade and the application are compatible and interchangeable products, enhance the comparability of calculation results, improve the design and selection of pipes for different applications.

In ISO/10400 calculation of the characteristics of a pipe with deterministic and probabilistic (or statistical) approaches, namely comparison of the expected loads, the effect of which will be pipe, and the expected resistance to such loads. As the load and the resistance of the pipes, separately or jointly, can be changed by using the corresponding estimated coefficients.

When a deterministic approach to calculate a single value indicators of operational properties of the structure using the nominal geometrical parameters and properties of the pipes. In the probabilistic approach, the same parameters and properties are used as random variables, which get the statistical distribution of the indicator operational properties. This distribution of performance properties in combination with certain lower percentile allows to end calculation formula.

ISO/10400 does not consider the calculations of wells in General and the definition of expected loads includes only the calculation formula used for determining the resistance of pipes to given loads, regardless of their origin. It also provides formulas limit values that can be used to determine the resistance of a specific sample with known geometry and properties, as well as the formulas used for the design of wells on the basis of conservative estimates of the geometric parameters and properties of pipes. The choice of values of the coefficients used for the calculations, possibly by the user of the standard.

This standard is modified in relation to ISO/10400 in connection with the need to complement sizes, types of threaded connections and groups-strength casing, tubing, drill pipe and pipes for pipelines, widely used in the Russian oil and gas industry.

Modification of this standard in relation to ISO/10400 consists of the following:

— supplemented formula and recommendations for pipes manufactured according to standards for casing and pump-compressor pipe (GOST R 53366), drill pipe (GOST R 54383) and pipes for pipeline (GOST ISO 3183);

— added calculations for casing and tubing steel grades K72 and Q135, outer diameters 146,05; 250,83; and 425,45 323,85 mm, threaded ATM, OCTG, tubing, NCTV, NKM;

— removed threaded coupling Extreme-line and Integral-joint not used in the Russian industry;

excluded values expressed in American units, which is impractical for national standardization, and the corresponding application L;

— callouts pipe sizes Number 1 and Number 2 is replaced by the corresponding values of the outer diameters and wall thickness, excluded the corresponding terms «Number 1 (label 1), Row 2 (label 2)»;

— information about the history of the development of the formulas is replaced by the corresponding references to the source of information.

The formulas and recommendations of this standard can be applied for the calculation of characteristics and properties of such tubes (including such threaded connections), manufactured according to the technical specifications and corporate standards.

1 Scope

This standard covers casing, tubing and drill pipes for the oil and gas industry, as well as for pipes for pipes used as casing and tubing.

This standard provides formulas and guidance needed to calculate various properties of the pipes including:

— performance properties (resistance to axial loads, internal pressure and collapse);

— physical properties;

— torque when screwing;

test hydrostatic pressure;

— critical dimensions of the products according to the criteria of the different tests;

— critical dimensions of testing equipment;

— critical dimensions of test samples.

The formulas for calculation of indicators of operational properties of products are shown information about the application of these formulas.

Given this standard formula and recommendations is designed to calculate the properties of the pipes manufactured in accordance with GOST R 53366, GOST R 54383 and GOST ISO 3183. Formula and recommendations can also be used to calculate the properties of the pipes manufactured according to other standards. The scope of this standard also includes a pipe subjected in the manufacturing process of cold deformation, for example cold rotary straightening. The scope of this standard does not include pipes, subjected to cold deformation after manufacture, such as hand or wound in coils.

Given this standard formula applicable to calculate the performance properties of the pipes according to GOST ISO 3183 only when using pipes such as casing and tubing in wells or in laboratory tests, subject to compliance of heat treatment processes, corrections, yield and other parameters of such tubes to the same processes, characteristics and parameters of casing and tubing pipes. With the same conditions this standard can be used to calculate properties of drill pipes.

This standard and these formulas allow to relate the source parameters for manufacturing of pipes according to GOST R 53366, GOST R 54383 and GOST ISO 3183 with the expected operational properties. The formula for calculating properties do not guarantee these properties. The manufacturer is entitled to manufacture pipes in accordance with the standards that establish their size and physical properties. Formulas provide a starting point for the consumer when assessing the performance of operational properties of pipes, design of wells or the study of the properties of the pipes.

This standard does not provide formal rules of design. It contains formulas and examples of calculating the properties of pipes for wells. It does not contain guidance on the determination of the loads acting on the pipe or on the required margin of safety. The consumer should determine the design load and select a margin of safety, ensuring the safety and efficiency of the design. Design load and factor of safety must be determined considering experience, industry rules and operating conditions of a particular well.

All formulas and indicators of operational properties given in this standard are intended for normal operating conditions and characteristics of the pipes appropriate GOST R 53366, GOST R 54383 and GOST ISO 3183. Calculations that may be required for special operating conditions, is given in Appendix D.

The scope of this standard does not include performance characteristics of tubes under dynamic loads and tightness of threaded connections of pipes.

In this standard, are always considered as positive tensile stresses.

2 Normative references

_______________
* The use of simultaneous references to two standards imply that these standards are interchangeable according to your requirements.


This standard uses the regulatory references to the following standards:

GOST ISO 3183−2012 steel Pipes for pipelines for oil and gas industry. General specifications

GOST R 51906−2002 threaded casing, tubing, and piping and thread gauges for them. General technical requirements

GOST R 53365−2009 Pipe casing and tubing couplings. Basic parameters and control of threaded connections. General technical requirements

GOST R 53366−2009 (ISO 11960:2004) steel Tubes used as casing or tubing for wells in petroleum and gas industry. General specifications

GOST R 54383−2011 (ISO 11961:2008) steel drill Pipe for the oil and gas industry. Specifications

Note — When using this standard appropriate to test the effect of reference standards in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet or in the annual information index «National standards» published as on January 1 of the current year, and the editions of the monthly information index «National standards» for the current year. If replaced with a reference standard, which was given an undated reference, then it is recommended to use the current version of this standard, taking into account all enabled in this version modifications. If replaced with a reference standard, which is given a dated reference, it is recommended to use the version of this standard referred to above by year of approval (acceptance). If after approval of this standard in the reference standard, which is given a dated reference, a change affecting a provision to which reference, the provision is recommended to be applied without taking into account this change. If the reference standard is cancelled without replacement, the position in which reference is made to him, recommended to be used in part not affecting this link.

3 Terms and definitions

This standard applies the terminology according to GOST R 53365 GOST R 53366, GOST R 51906, as well as the following terms with respective definitions:

3.1 probabilistic approach (probabilistic method): Approach, according to which to calculate the allocation of operational properties using the distribution of geometrical parameters and properties of the metal.

3.2 principal stress (principal stress): Stress in the main plane in which shear stress is zero.

Note — for any stress state at any point there are three mutually perpendicular planes where the shear stress is zero. The components of the normal stresses in these planes are principal stresses. The largest of these three stresses is called the greatest main stress.

3.3 burst pressure (fracture pressure): Internal pressure, which is the destruction of the pipe due to the proliferation of imperfections.

3.4 a deterministic approach (deterministic method): an Approach that assumes that all variables that determine the operational properties are accurately known.

Note — Indicators of operational properties of the tubes depend on one or more control parameters. In the formulas used in the deterministic approach uses specific geometric parameters and properties of the metal to calculate a single value indicators of operational properties. In design calculations, this value is expected minimum.

3.5 the true curve of stress-strain (true stress-strain curve): Curve in coordinates of true stress (ordinate) is logarithmic strain (abscissa).

3.6 true stress, the Cauchy stress (true stress, Cauchy stress): Stress, defined as the ratio of the efforts acting on the body surface to the target area of the surface.

3.7 the coefficient of variation (coefficient of variance): a Dimensionless random variable, defined as the ratio of standard deviation to average value.

3.8 logarithmic strain (logarithmic strain): the Value of linear deformation of the pipe body is equal to the natural logarithm of the ratio of the final length of the pipe body to its initial length.

Note — Logarithmic strain can also be equal to the natural logarithm of the sum of units and the estimated deformation.

3.9 plastic fracture (ductile rupture): the destruction of the pipe body in the area of plastic deformation caused by internal pressure and/or longitudinal stretching.

3.10 the calculated deformation (engineering strain): the Value of linear deformation of pipe body, which is defined as the change in the length of the pipe body to its initial length.

3.11 the calculated stress (engineering stress): Stress, defined as the ratio of the efforts acting on the surface of the body to the initial area of the surface.

3.12 guide (template): the document containing the formulas, methods, tests and measurements intended to establish the design parameters of operational properties.

3.13 offset yield strength (yield stress bias): a quantity defined as the ratio of actual yield stress to specified minimum yield strength.

3.14 statistical approach (synthesis method): Approach, according to which the uncertainty and likely values of the performance properties of the pipes is determined using the distribution of indicators of geometrical parameters and properties of the metal.

Note — To determine the statistical distribution of indicators of operational properties of this distribution is considered in combination with the formula of the limit values. The distribution of performance properties in combination with found a lower percentile determines the final form of the calculation formula.

3.15 turnover (yield): Permanent inelastic deformation.

3.16 the fluidity of the pipe body (pipe body yield): Stress state, which starts the metal flow at any point of the pipe body.

3.17 the level of acceptance (inspection threshold): Maximum size of imperfection type cracks, valid established requirements.

3.18 formula limit values (limit state equations): Formula which according to the geometrical parameters and the properties of the metal sampling tubes allow you to determine the failure criterion of pipe.

Note — According to the formula of the limit values determined with maximum precision operational properties of the individual sample tubes excluding extreme deviations of this sample.

3.19 formula design limit value (design equations): Formula for based on the requirements of the standards or measurements to identify indicators of operational properties used in design calculations.

Note — the Formula project limit values can be obtained by substituting reasonable limits variables into the formula limit values to determine the expected performance of operational properties with a given level of security. Formula design limit values, derived statistical way, corresponds to a certain lower percentile of the distribution curve of the probability of resistance.

3.20 the number of threads per inch (threads per inch): the Number of threads per length of 25.4 mm.

Note — 1 coil per inch equal coils on 0,0394 mm, 1 revolution per millimeter is equal to 25.4 mm round on a inch.

3.21 the effective stress (effective stress): Stress, considering the stress caused by pressure and axial stress used in this standard with the aim of simplifying the formulas.

Note — the Effective stress in the form in which it is used in this standard, does not represent a specific physical quantity. It represents the amount depending on longitudinal stress, internal pressure, external pressure and pipe sizes, for use in some formulas. It is sometimes called a fictitious voltage lyubinskiy.

4 Denote

This standard applies the following designations:

 — tightness in case of manual screwing;

 — distance from the coupling face to the base of the triangle mark in case of manual screwing;

 — the area of the critical cross section of the weaker component connections;

, ,  — fixture dimensions for the test of directed bend;

 — the critical size of test fixtures directed bend;

 — the cross-sectional area at the inner diameter;

the cross — sectional area of the coupling;

the cross — sectional area of the pipe in the plane of the last threads with a full profile;

 — the cross-sectional area at the outer diameter;

the cross — sectional area of the pipe;

 — the average cross-sectional area of the pipe;

the cross — sectional area of sample for tensile testing;

 — in the formula of the limit values — maximum the actual depth of the imperfection type cracks; in the formula design limit values, the maximum depth of the imperfection type cracks, undetected by the control system;

the depth of the imperfection, comparable with a specific level of acceptance, i.e. maximum depth of the imperfection type cracks, which can be accepted by the control system as a valid imperfection;

 — the average value of the relations used in regression analysis;

 — parameter Weibull distribution;

 — the distance between the walls of the matrix or the supports during the test for a directed bend;

 — pipe bending — the reciprocal of the bending radius of the pipe axis;

 — random variable characterizing the uncertainty of the model;

the inside diameter of the pipe;

 — inner diameter of the landing;

the inside diameter of the pipe calculated ratio ;

the diameter of the root of the thread of the coupling in the plane of the end pipe with mechanical screwing;

the inside diameter of the pipe thread in the plane of the coupling face when the mechanical make-up, mm;

 — nominal outside diameter of the pipe;

 — the average outside diameter of the pipe after a cut;

 — the average outside diameter of the pipe;

 — average outer diameter of the tube to the incision;

— nominal outside diameter tube connectors;

 — outer diameter of the end plane of the conventional couplings with special bevel;

 — nominal outside diameter of a conventional clutch;

 — the maximum outer diameter of the pipe;

 — minimum outside diameter of the pipe;

 — outer diameter of pipe thread;

 — young’s modulus;

 — the average diameter of the thread in the middle of the coupling of the compounds of the sun and OTM or the inner diameter of the bore of the coupling of the compounds of the NKM and OTH;

 — the average diameter of the thread in the plane of the coupling face;

 — the average diameter of the thread in the plane of the pipe end;

 — the average diameter of the thread in the plane of the hand Assembly;

 — the average diameter of the thread in the main plane;

— Euler’s number or the base of the natural logarithm equal to 2,718281828;

— eccentricity;

 — degrees of freedom;

 — density function the cumulative probability variable vector ;

 — cut hollows of the profile of pipe thread;

 — axial force;

— component of the effective axial forces are not caused by the bending;

effective axial force;

 — the axial force in case of turnover according to the formula of Barlow;

 — length of thread with an incomplete profile.

 — the function of the limit values;

 — coefficient of influence for the curve FAD limit values;

 — coefficient of influence for the curve FAD limit values;

 — coefficient of influence for the curve FAD limit values;

 — coefficient of influence for the curve FAD limit values;

 — coefficient of influence for the curve FAD limit values;

 — the height of the trapezoidal profile of the thread;

 — coefficient taking into account the shape of the curve stress-strain;

 — the height of the triangular profile of the thread;

 — height of the original triangular profile of the thread;

is the moment of inertia of the cross section of the pipe;

 — the average moment of inertia of the cross section of the pipe;

 — the bending moment;

 — polar moment of inertia of the cross section of the pipe;

 — distance from the pipe end until the middle of the clutch when the mechanical make-up;

 — resistance metal to destruction;

 — the resistance of a metal to fracture in a particular environment;

the stress intensity factor on the basis of J-integral;

J-integral — intensity of the field of stresses and strains near the tip of the crack;

the stress intensity factor at the crack tip;

 — intermediate variable in the formula for the yield criterion of von Mises according to the standard [1] or [2];

 — strength ratio at failure obtained according to test results;

 — intermediate variable in the formula for the yield criterion of von Mises according to the standard [1] or [2];

 — intermediate variable in the formula for the yield criterion of von Mises according to the standard [1] or [2];

is a constant in the formula for elastic buckling;

 — correction coefficient taking into account the deformation of the pipe and strain hardening of metal;

 — shift factor for elastic collapse;

 — the reduction factor for design elastic collapse;

 — aspect ratio;

 — correction factor for the limiting values of the elastic shear;

— correction factor for data set table E. 1;

 — the coefficient to determine the minimum wall thickness of the pipe sufficient to create a cross-sectional sample for testing the impact strength;

 — coefficient of hardening of the curve for the true stress-strain;

 — the conversion factor length;

 — coefficient of fracture toughness of metals in a particular environment;

 — correction factor for the calculation of the mass;

 — the ratio of the voltages;

 — the ratio of stress caused by internal pressure, and yield stress;

geometric ratio of the upper quadrant in the formula of the yield criterion of von Mises according to the standard [1] or [2];

 — geometric coefficient lower quadrant in the formula of the yield criterion of von Mises according to the standard [1] or [2];

 — stress intensity factor;

 — correction factor for the deviation from the mean;

 — the reduction factor in the formula design limit values;

 — the reduction factor in the formula of the limit values;

 — coefficient taking into account the set limit deviation of the wall thickness of the pipe;

 — the ratio of the mass per unit length;

— correction factor for calculating the average diameter of the thread in the plane of the coupling face;

 — shift factor for plastic collapse;

 — the reduction factor for the design of plastic crumpling;

 — correction factor for the limiting values of plastic shear;

 — sensitivity coefficient;

— the length of the transition phase, the internal upsetting;

 — the length of the C-shaped sample;

 — distance from the pipe end to the beginning of the transition phase of the landing;

 — the minimum thread length with vertices a complete profile from the pipe end;

 — length of pipe subject to the finishing ends;

- length pairing with mechanical bolted connections with a nominal geometric parameters;

— the length of the transitional phase external upsetting;

the length of the inner landing;

the length of the pipe;

 — the length of the coupling;

 — deterministic nominal load;

 — the load factor;

 — the total length of the pipe thread;

 — distance from end of pipe to plane of hand-screwing;

 — the length of the pipe thread with a full profile;

— estimated weight of the pipe;

is the mass of a conventional clutch;

 — the mass of the clutch casing ;

 — mass clutch, removed during the performance of a special chamfer;

 — the mass of the coupling with special bevel;

— weight of tube with outer and inner vysotkah;

— increased mass of a pipe at the outer landing;

— increased mass of a pipe at the inner landing;

 — estimated weight of the pipe length ;

 — weight tubes without thread and landing per unit length;

 — mass removed in threading on the pipe;

 — weight pipe with threaded and coupling per unit length;

 — mass of tube after landing on the unit length;

 — the uncertainty of the model;

— distance from the coupling face to the plane of the hand Assembly;

 — torque;

— the number of tests crushing;

 — the number of tests;

 — number of turns in the coupling;

 — ovality;

is the thread pitch;

— operating pressure;

 — pressure collapse;

— limit pressure;

 — pressure shear in the presence of internal pressure;

 — design pressure shear;

 — design pressure shear adjusted to an internal pressure;

in the pressure — shear adjusted for axial tension and internal pressure;

 — pressure elastic collapse;

 — pressure elastic collapse;

 — design pressure for elastic collapse;

 — limit pressure of elastic buckling;

— the probability of failure of a pipe at plastic collapse;

test hydrostatic pressure;

 — internal pressure;

 — internal pressure at fracture;

 — the internal pressure at the occurrence of leakage;

 — the internal pressure at the destruction of the plastic pipe with mechanical seal;

 — adjusted for axial load and external pressure;

 — the change in the pressure of the threads of the coupler and nipple each other as a result of make up after application of internal pressure;

 — the internal pressure of the occurrence of fluidity in thin-walled pipe;

 — the internal pressure of the occurrence of yield in the coupling;

 — the internal pressure of the occurrence of yield in a thick-walled tube with mechanical seal;

 — the internal pressure of the occurrence of yield in a thick-walled tube with open ends;

 — the strength of the connection;

 — the pressure difference;

 — external pressure;

the ultimate external pressure at collapse;

 — pressure plastic collapse;

 — the pressure medium plastic crumpling;

— the pressure of the threads of the coupler and the nipple to each other as a result of the screwing;

— limit the pressure tightness of the connection;

 — pressure transient collapse;

 — pressure limit of the collapse;

 — pressure plastic collapse;

 — the pressure difference of the plastic crumpling;

 — design pressure of plastic crumpling;

 — the difference between the pressure on von Mises and wall thickness;

 — pressure bearing failure by reaching the yield strength;

 — pressure plastic collapse in the Cod;

 — pressure limit of plastic collapse;

 — pressure plastic collapse according to von Mises;

 — bore diameter in the plane of the coupling face;

radial coordinate;

— radius of mandrel (punch) testing is directed bend;

— radius of matrices for testing directed bend;

 — residual voltage at the negative compression on the inner surface;

 — cut hollows of the triangular profile of the thread;

 — the standard deviation of the ratio used for the regression analysis;

 — the distance between the plates during the flattening;

 — the standard error of estimate for the regression formula;

 — nominal thickness of tube wall;

 — average wall thickness without consideration of imperfections such as cracks;

 — average wall thickness of the pipe;

 — maximum wall thickness of the pipe;

 — the minimum wall thickness of the pipe;

 — maximum wall thickness without consideration of imperfections such as cracks;

 — minimum wall thickness without considering imperfections such as cracks;

 — taper;

 — vector of random variables;

 — reliability index first order;

 — coefficient of deformation;

 — logarithmic strain;

 — deformation corresponding to the established minimum yield strength;

— the average value;

the average value of the pressure of collapse for a set of test results crushing;

 — average calculated eccentricity;

the average calculated value ;

 — the estimated average roundness;

the average estimated residual voltage at the negative compression on the inner surface;

 — Poisson’s ratio;

 — the number PI;

 — the probability of failure;

 — angle special bevel;

 — unaccounted share of the population;

 — standard deviation;

 — the component of axial stress not due to bending;

 — component is the axial stress caused by bending;

 — the true stress (Cauchy stress);

 — equivalent stress;

is the effective stress;

 — stress in pipe wall during hydrostatic test;

 — tangential stress;

 — maximum primary voltage;

 — radial stress;

 — residual voltage;

 — the standard deviation of a set of test results crushing;

 — threshold voltage;

 — the limit of the tensile strength of the representative sample;

 — specified minimum ultimate strength in tension;

 — the specified minimum tensile strength for the coupler;

 — the specified minimum tensile strength for the pipe body;

 — tensile strength of a representative tensile specimen for pipe body;

 — yield strength of a representative tensile specimen;

 — equivalent yield strength in the presence of axial stress;

the equivalent yield stress in the presence of axial stress;

 — the specified minimum yield strength of tensile;

 — the specified minimum yield strength in tension for the clutch;

 — the specified minimum yield strength in tension for pipe body;

 — yield strength of a representative tensile specimen for pipe;

 — elongation at rated sample length 50,0 mm;

 — shear stress in torsion;

is the change of mass in the decoration of the ends.

5 Reduction

This standard uses the following abbreviations:

All — type connection resistant casing pipes with trapezoidal thread;

EU — type of connection tubing external upset tubing with a triangular thread;

FAD — diagram evaluation of failure probability;

LC — type connections of casing pipes with a long triangular thread;

NU — type connection of the tubing with a triangular thread;

PDF the parameters of probability distribution functions;

CDF — cumulative distribution function;

SC — type connection pipe casing with a short triangular thread;

FEM — the finite element model;

Tubing — type of connection of the tubing with a triangular thread;

NCTV — type of connection tubing external upset tubing with a triangular thread;

NKM — connection type of pump-compressor pipes with trapezoidal thread and seal Assembly «metal-metal»;

ATM — type connection of casing pipes with trapezoidal thread;

OTTG — type connection of casing pipes with trapezoidal thread and seal Assembly «metal-metal».

6 three-Dimensional fluctuation of the pipe body

6.1 General

In the analysis of three-dimensional yield strength for the pipe body using the criterion of von Mises. Elastic condition, and the resulting yield occurs when applying the following factors:

a) the radial and tangential stresses are defined by the formulas Lama for a thick-walled cylinder;

b) uniform axial stress from all sources, in addition to bending;

c) the axial bending stresses for timber Tymoshenko;

d) shear stress torsional moment directed along the axis of the pipe.

More detailed information on the calculation of three-dimensional yield strength for the pipe body shown in Annex A.

6.2 Assumptions and limitations

6.2.1 General provisions

Formulas (1) to (7) based on the given in 6.2.2 to 6.2.5 assumptions.

6.2.2 Concentric and circumference of the pipe cross section

Formulas for radial and tangential stresses, bending and torsion based on the assumption that the cross section of the pipe consists of inner and outer circles concentric with and having the correct form.

6.2.3 Isotropic fluidity

The yield strength of the pipe is assumed independent of direction. It is assumed that the properties of longitudinal and transverse samples is identical, they have identical elastic moduli and yield limits in tension and compression.

6.2.4 the Absence of residual stresses

In determining the occurrence of yield it is assumed that residual stresses generated during the manufacturing process, can be neglected.

6.2.5 Instability of the cross-section (collapse) and longitudinal instability (vignette)

When possible crushing of the cross section due to buckling before yielding. Case collapse when external pressure more than internal, see section 8. Similarly, when 0 the possible loss of longitudinal stability of the pipe before the emergence of stress, and bending stresses from vignette must be considered when checking for fluidity.

6.3 Requirements for input data

To calculate the three-dimensional yield strength for the pipe body requires the following initial data:

 — the bend — the reciprocal of the bend radius to the pipe axis, rad/m;

 — nominal outside diameter of pipe, mm;

 — axial force, N;

 — the specified minimum yield strength tensile, MPa;

 — coefficient taking into account the set limit deviation of the wall thickness of the pipe, equal to 0,875 limit deviation-12.5%;

 — internal pressure, MPa;

 — outer pressure, MPa;

is the applied torque, N·m;

 — the nominal wall thickness of pipe, mm.

6.4 Formula project three-dimensional yield strength pipe body

The appearance of fluidity is determined by the following equation

, (1)

where corresponds to the elastic condition;

 — equivalent stress, MPa;

 — the specified minimum yield strength in tension, MPa.

Equivalent stress is calculated by the formula

; (2)

at the same time:

; (3)

; (4)

; (5)

; (6)

; (7)

where is the equivalent stress, MPa;

 — radial stress, MPa;

 — tangential stress, MPa;

 — the component of axial stress not due to bending, MPa;

 — component of axial stress due to bending, MPa;

 — shear stress in torsion, MPa;

 — internal pressure, MPa;

the inside diameter of the pipe, calculated with the coefficient equal to , mm.

 — coefficient taking into account the set limit deviation of the wall thickness of the pipe, equal to 0,875 limit deviation-12.5%;

 — the nominal wall thickness of pipe, mm;

 — outer pressure, MPa;

 — nominal outside diameter of pipe, mm;

radial coordinate, for , and , for and ;

the inside diameter of the pipe, equal to , mm.

 — axial force, N;

the cross — sectional area of the pipe, equal to , mm;

 — bending moment, N·m;

is the moment of inertia of the cross section of the pipe, equal to , mm;

 — young’s modulus equal 206,9 HPa;

 — the bend — the reciprocal of the bend radius to the pipe axis, rad/m;

is the applied torque, N·m;

 — polar moment of inertia of the cross section of the pipe, equal to , mm.

The sign ± in equation (6) indicates that the component of axial stress due to bending can be positive (tensile) or negative (compressive) depending on the position of the considered point of the cross section. From bending at the points of the cross-section located closer to the center of the radius of bending than longitudinal pipe axis, there are compressive stresses, and the points of the cross section farther from the center of the radius of bending than longitudinal pipe axis, tensile stresses occur.

The unit of measurement of a variable is the radian per meter, which is not typical for the oil and gas industry. Often used unit of measurement of the variable is in degrees per 30 m For translation units of measure in degrees per 30 m in radians per meter the right part of formula (6) should be multiplied by a constant /(180·30) or 5,8178·10.

In the presence of a bending formula (2) should have 4 solutions: for the outer and inner surface of the pipe in tension and compression. In the presence of torsion the formula (2) should have 2 solutions: for the outer and inner surfaces of the pipe. In the absence of torsion and bending formula (2) should have one solution: for the internal radius of the tube. In all cases, in the formula (1) be either the highest calculated value .

The result of the calculation in this sub-section, determine the stress state, leading to the yield strength of the metal pipes in the worst-case properties of this metal, i.e. the minimum acceptable values of these properties. The thickness of the wall of the pipe is to be equal to the minimum acceptable wall thickness in the eccentricity, which is a natural factor in the production of pipes.