Magnetic Field of a Circular Butt Weld of a Trunk Oil and Gas Pipeline

Reutov, Yu. Ya.; Loskutov, V. E.; Gobov, Yu. L.; Vaulin, S. L.

doi:10.1023/b:runt.0000023755.64012.08

Cited by 6 publications

(6 citation statements)

References 1 publication

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“…When H 0 increases, these curves behave in the same way as described in [1] and in the introduction above. This means that, in weak fields, the leakage fields are mainly contributed by the difference in the magnetic permeabilities of the pipe and the welded joint.…”

Section: Results Of In-tube Testing Of the Tangential Component Of Thsupporting

confidence: 50%

“…For these reasons, to ensure the required strength and tightness of a welded joint, the gaps that inevitably appear should be filled with the material of an arc-welding electrode. As a result, in addition to reinforcement beads (collars) on the interior and outer sides of a welded joint [1], "steps" often appear, which are due to spatial mismatch of the segments of the pipes' ends ( Fig. 1).…”

mentioning

confidence: 97%

“…Study [1] contains the results of a computer simulation of the magnetic field created by a transverse welded joint. We performed this simulation using the ELCUT 4.2 code (see, e.g., [2]).…”

mentioning

confidence: 99%

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A Dipole Model for Magnetic Leakage Fields Created by a Circular Butt-Welded Joint

Gobov

Loskutov

Reutov

2005

Russ J Nondestruct Test

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Magnetic leakage fields created by circular butt-welded joints of a trunk pipeline are characterized by a variety of topographies differing in both shape and extension. Four sources of magnetic leakage fields around a circular welded joint are distinguished. Each source is simulated by a dipole moment with certain parameters. The developed mathematical model makes it possible to describe with high accuracy the entire variety of topographies of leakage fields around circular butt-welded joints of a trunk pipeline.When an oil or gas trunk pipeline (OGTP) is constructed, the pipes of which it consists are butt jointed by welding. The properties of the transverse welded joints differ significantly from those of longitudinal or spiral welded joints in the pipes they connect. The reason for these differences is that the longitudinal and spiral welded joints are created under strictly controlled manufacturing conditions, while butt-welded joints are created under field conditions where the manufacturing prescriptions can be observed only with great difficulty and the control over their implementation is even more problematic. For a pipe around 1.5 m in diameter and 10 to 15 m long, it is virtually impossible to ensure strict alignment of the joints of pipe walls 15 to 25 mm thick along the entire circumference; moreover, the welded pipes may have different thicknesses. For these reasons, to ensure the required strength and tightness of a welded joint, the gaps that inevitably appear should be filled with the material of an arc-welding electrode. As a result, in addition to reinforcement beads (collars) on the interior and outer sides of a welded joint [1], "steps" often appear, which are due to spatial mismatch of the segments of the pipes' ends ( Fig. 1).In the process of magnetic in-tube diagnostics of operating oil and gas pipelines, the magnetic leakage fields created by transverse butt-welded joints are recorded (along with fields of flaws) by an acoustic flaw detector to be further used both for referencing segments of an oil or gas pipeline to the path passed by a flaw detector (for a path length up to 100 km) and for timely forecasting of possible violations of the butt integrity and preventing emergencies.The in-tube testing is conducted in an applied magnetic field directed along the pipe's longitudinal axis. The strength of the magnetizing field is usually such that the material of the pipe is saturated (the induction is ~1.5 T). During testing, the tangential component of the magnetic field strength directed along the pipe's axis is measured at a distance of ~5 mm from the inner surface of the pipe's wall.Study [1] contains the results of a computer simulation of the magnetic field created by a transverse welded joint. We performed this simulation using the ELCUT 4.2 code (see, e.g., [2]). Since the diameter of a pipe is significantly larger than the thickness of its wall, the problem was simulated on a plane. Here, the main results of the simulation that were used in the cited article for developing a mathe...

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Section: Results Of In-tube Testing Of the Tangential Component Of Thsupporting

confidence: 50%

mentioning

confidence: 97%

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A Dipole Model for Magnetic Leakage Fields Created by a Circular Butt-Welded Joint

Gobov

Loskutov

Reutov

2005

Russ J Nondestruct Test

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“…We should distinguish the application of proton magnetometers which find the location [3] and defects [4,5] of joint welds that might be useful for defectoscopy, mapping and pipeline certification. The actual magnetic profile of a pipeline is rather complicated as it includes:…”

Section: Magnetic Field Of the Pipelinementioning

confidence: 99%

“…-magnetically hard and soft magnetization of pipes themselves; -field of joint welds with their defects [3,4]; -anomalies related with the stresses appeared during the process of installation, as well as due to the natural dynamic processes in the base of pipelines [1]; -anomalies due to defects [1,5]; -the magnetic field of anthropogenic objects located near the pipeline, as well as the heterogeneity of the pipeline installation [6]. For an efficient solution to the problems related to pipeline magnetometry it is important to make a correct choice of a physical model of the object under consideration according to which the anomalies of the magnetic field would be registered.…”

Section: Magnetic Field Of the Pipelinementioning

confidence: 99%

Novel quantum NMR magnetometer non-contact defectoscopy and monitoring technique for the safe exploitation of gas pipelines

Narkhov¹,

Sapunov²,

Denisov³

et al. 2014

WIT Transactions on Ecology and the Environment

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Pipeline transportation has already proved to be a high-performance tool of resources transportation for the efficient functioning of modern society. However, an aggressive environment, the modernization of existing pipelines and the building of new pipelines pose a number of problems to be solved for secure exploitation. Such problems include mapping, systems certification, technical inspection and monitoring. Recently much attention has being paid to the effective solution of these problems, with no interference into the functioning of the existing systems (non-contact methods), and the magnetometric technique is one such method. The method presented in this paper is based on the interpretation of the absolute value of the magnetic field of an object, which allows us to carry out measurements more accurately compared to other approaches. This paper presents the preliminary results of the usage of high-precision absolute quantum Overhauser "POS" (proton Overhauser sensor) magnetometers in the oil-and-gas field. The field work conducted in the summer of 2013 showed that this equipment has great potential for safe exploitation of oil-and-gas pipelines. The efficiency of the geophysical equipment for gas pipelines of a large diameter (1400 mm) was also confirmed under actual operating conditions.

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Topography of the field of a slot upon nonlinear magnetization

Reutov

Loskutov

2004

Russ J Nondestruct Test

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The results of computer simulation of the magnetic field of a slot in a flat plate are presented. The simulation was performed with allowance made for the nonlinearity of the magnetization curve of the plate's material. A number of peculiarities of the topography of this field, which are explained by a redistribution of volume magnetic charges over the plate body at different portions of the magnetization curve, were discovered. The simulation was performed for the needs of intrapipe diagnostics and flaw detection.In spite of the existence of numerous publications (see, e.g., [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]), the study of the magnetic field of a slot in an article made of a ferromagnetic material cannot be recognized as complete. We hope that this work will be useful both for understanding the processes of field formation in a slot and for practical use in flaw detection.Here, we present the results of a numerical simulation of the field of a rectangular slot using an ELCUT 4.2 program [21,22] performed taking into account the nonlinearity of the material magnetization curve. From the practical point of view, we are interested in the intrapipe nondestructive testing and diagnostics of pipes of oil and gas pipelines laid in earth; because of this, we simulated the field of a slot in a pipe with a diameter of >1 m and a wall 25 mm thick. It is obvious that, during the simulation, the problem can be considered as a two-dimensional task in considering a plate of the same thickness instead of the pipe wall. Taking into account practical use, we studied predominantly a tangential component (parallel to the plate surface) of the crack field at a distance (unless otherwise specified) of 5 mm from the plate surface both on the side of the cropping out slot and on the flaw-free side. In the simulation, the crack depth and width (opening) were taken to be equal to 5 and 0.1 mm, respectively. A magnetizing field was applied along the plate transversely to the crack. The field of the crack at each point was calculated as the difference between the field values in the presence and absence of a crack.Simulation was performed for the following parameters of the magnetization curve of the plate's material: the relative initial magnetic permeability is µ a = 100; the maximum relative permeability is µ max = 407; the field, in which the maximum permeability is reached, is H µ max = 1.5 kA/m; the saturation induction is B s = 2.1 T; and the coercive force is H c = 1.1 kA/m.The following five values of the magnetic field strength corresponding to the most characteristic portions of the magnetization curve were given: the field in which the permeability of the material is close to the initial magnetic permeability; the field corresponding to the increasing permeability as the magnetizing field increases; the field corresponding to the maximum permeability; the field at which the permeability has decreased from the maximum value to the value approximately equal to the initial permeability; and, l...

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Magnetic Field of a Circular Butt Weld of a Trunk Oil and Gas Pipeline

Cited by 6 publications

References 1 publication

A Dipole Model for Magnetic Leakage Fields Created by a Circular Butt-Welded Joint

A Dipole Model for Magnetic Leakage Fields Created by a Circular Butt-Welded Joint

Novel quantum NMR magnetometer non-contact defectoscopy and monitoring technique for the safe exploitation of gas pipelines

Topography of the field of a slot upon nonlinear magnetization

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