SU1640382A1 - Collar locator - Google Patents

Abstract

The invention relates to well logging. The purpose of the invention is to increase the sensitivity. The locator coupling contains a sealed non-magnetic housing 5, which houses the magnetic system. It includes cores (C) 1 and 2 with current coils and core 3 with a measuring coil and pole pieces (H) 4. The pole H 4 are made with additional coaxially mounted cylinders. Additional cylinders H 4 have a smaller diameter compared to C 1, 2 and 3. The latter are installed with the possibility of 6 i tf C O 4 O with 00 1C

Description

adjusting the gap between them to compensate for the initial imbalance of the magnetic system. An alternating current is supplied to the current coils, which creates in C 1 and 2 opposite magnetic fluxes concentrating on H 4 and closing on the string of pipe 7. At the moment when the opposite magnetic fluxes through H 4 close on the string of pipes 7 with non-uniform magnetic properties, the total the magnetic fluxes are not compensated for in C 3. The differential variable magnetic flux induces the ECS in the measuring coil. 1 il.

This invention relates to geophysics.

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boreholes and can be used for beating coupling and locking joints of a pipe string

The purpose of the invention is to increase the sensitive styo20

The drawing shows the clutch locator in the sectional

The locator coupling contains a magnetic system, including cores 1 and 2 with current coils and a core 3 25 with a measuring coil. Core 3 has pole tips 4, which are made in the form of two successive cylinders of different diameters. The magnetic system is placed in a sealed 0 non-magnetic, electrically insulating casing 5. The extreme cylinders of pole, tips 4 have a smaller diameter compared to cores 1

2 current coils and a core of 3 out of 35 measuring coil. Cores 1,2

and 3 with pole pieces 4 are installed with a gap between them. The coupling locator suspended on the wireline b is located in the pipe string 7c40 by a coupling or a locking joint 8.

The cores 1 and 2 of the current coils and the core 3 of the measuring coil with pole pieces 4 are aligned with a gap between them. The coil currents 45 are turned on counter to create oppositely directed magnetic fluxes in the core 3 and its pole pieces 4, Nearest the core,

The 3-cylinders of the pole tips 4 06-50 open the shoes on which the opposing magnetic fluxes are concentrated and

are pushed beyond the limits of the housing 5 and closed on the string of pipes 7 with the coupling or locking connection 8. 55

By moving the core 3 with the measuring coil and the pole pieces 4 in the axial direction in a small range is established

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balance of oncoming magnetic flux with high accuracy.

Locator couplings works as follows.

In the string of pipes 7 with coupling or lock joints 8, a coupling locator is lowered on the logging cable 6. During the movement of the coupling locator in the solid part of pipes with uniform magnetic properties, the output signal in the core 3 measuring coil is absent.

. Current coils with cores 1 and 2 are supplied with an alternating low-frequency current, which creates in the cores 1 and 2 opposite magnetic fluxes, concentrating on the pole tips 4 and closing on the string of tubes 7. Due to the pole tips 4 in the form of two consecutive cylinders of different diameter, the opposing magnetic the fluxes acquire the same directionality and value, which makes it possible to accurately compensate both magnetic fluxes in the core volume of 3 "

Since the magnetic properties of the continuous part of the column of pipes 7 are uniform, the opposite magnetic fluxes are equal and there is no alternating magnetic flux in the core / e 3

At the moment when the opposite magnetic fluxes through the pole pieces 4 are closed on a string of pipes 7 with inhomogeneous magnetic properties, T0e0 with different magnetic resistances (locking connections, couplings, local defects, etc.), the total magnetic fluxes are not compensated for. core 3 Differential variable magnetic flux induces a proportional EMF in the measuring coil.

The resolution of the coupling locator, t-e. Differentiation of sections of pipe string by section and locale5164

defects are determined by the distance between the pole pieces 4 of the core 3.

The use of the coupling locator with the minimum possible distance between the pole pieces allows to detail the areas inside the coupling and lock connections for precise fitting of the geophysical equipment in the study of wells and the elimination of accidents.

Increasing the sensitivity of the coupling locator, obtained by increasing the signal-to-interference ratio with the simultaneous independence of the value of the useful signal from the speed of its movement, improves the efficiency and productivity of geophysical work in wells due to a reduction in the time for repeated tripping operations.

Claims (1)

Formula invention A coupler locator containing a sealed, non-magnetic housing in which a magnetic body is housed: a system including coaxially mounted current and measuring coils with cores and pole pieces, the measuring coil being located between current coils that are turned on counter to each other, in order to increase the sensitivity it is equipped with cylinders, which are aligned, coaxially on the pole tips, which have a smaller diameter compared to the cores of the current and measuring coils, while the cores themselves ki are arranged to adjust the gap between them to compensate for the initial imbalance of the magnetic system