SU589379A1 - Device for identifying threaded connections in pipes - Google Patents

Description

The invention relates to the mining industry, namely, devices for determining the location of threaded connections in pipes and can be used in response to accidents with tubing strings in a well.

Coupling locators for casing strings used in conjunction with a drill string pipes 1 are known.

It is also known a device for determining threaded connections in pipes, comprising a multilayer coil with an iron core and permanent magnets on the ends of the core parallel to the axis of the instrument, an electrical input, an instrument head, a nonmagnetic body 2.

However, in known devices, the sensitivity zone extends to the entire volume of magnetic changes in the pipe. The presence of false anomalies on the magnetic field change curve makes it difficult, and in some cases makes it impossible to isolate threaded connections.

The purpose of the invention is to improve the accuracy of determining threaded connections by preventing false positives of the device from accidental interference.

This is achieved by the fact that the device is equipped with a logic circuit AND, and the sensor is not equipped with

less than one additional coil, while the cores of the coils are made of permanent magnets, and the casing is made of ferromagnetic material with sockets, each of which has coils, and sockets 5 are hermetically sealed with stoppers of nonmagnetic material, and the coils are connected to the inlet; P; logical scheme I.

FIG. 1 shows the proposed device, the cut; in fig. 2 is a section A - A in FIG. one.

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The device has an electrical input 1, numbered in the instrument head 2, body 3, connected to the instrument head 2 by means of a thread and a seal 4 on rubber rings, a logic circuit 5 placed on the mounting

5 to board 6 in housing 3 and connected to electrical input 1 by means of wires 1,. In the housing 3 there are made sockets in which coils 8 with permanent magnets 9 are placed. Hermetic sealing of the socket is carried out by stopper 10 of diamagnetic steel and sealing

0 ring of soft metal 11 (e.g. copper, lead).

The device works as follows. Through the electrical input 1 a direct current source is connected. As the device moves along the tube string, induction emf is induced in the induction sensor coils, which is fed to the inputs of the AND 5 logic circuit, assembled, for example, on transistors. When signals from all coils 8 are simultaneously received at the inputs of logic circuit 5, a current passes through the latter from a direct current source, part of which is recorded in the diagram at the appropriate depth scale with the aid of a recorder. In the absence of a signal, at least at one input of a logic element - it is locked, the passage of current is stopped. In this way, interference is filtered and the signal is received from the threaded connection.

The use of at least two coils with cores of permanent magnets located at the same level and a logic circuit And will allow filtering magnetic interference, recording signals from threaded connections and unambiguously isolating them. As a result, the time to eliminate the accident from the column pipe will be reduced and the efficiency of the emergency will increase.

F. formula

A device for determining threaded connections in pipes, comprising an electrical input, an instrument head and a sensor including a core coil, characterized in that, in order to improve accuracy by preventing false alarms, it is equipped with a logic circuit And, and the sensor is equipped with at least one an additional coil, while the coil cores are made of permanent magnets, and the casing is made of ferromagnetic material with sockets, each of which has coils, and the sockets are hermetically sealed with nonmag plugs material, and the coils are connected to the inputs of the logic circuit I.

Sources of information taken into account in the examination:

1. US patent No. 3177941, CL. 166-64, 1965.

2. Grigor N.N.T. et al. Riflement and blasting operations in a well, Moscow, “Subsurface 1972, p. 237-241.

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