RU2600502C1 - Borehole pulse plasma source with contactor-discharger - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, particularly, to well logging instruments. Downhole source of plasma-pulse action includes a housing, in which there is a control unit connected with electric energy accumulator, and plasma emitter connected to a mechanism for feeding metal conductor. Between electric energy accumulator and plasma emitter there is an electromechanical contactor-arrester comprising movable and fixed contacts. Fixed contact is connected with a high-voltage positive bus of electric energy accumulator, and movable contact with the help of flexible insulated conductor is connected to high-voltage electrode of plasma emitter.

EFFECT: higher reliability of well source of plasma-pulse action.

9 cl, 2 dwg

Description

FIELD OF TECHNOLOGY

The invention relates to the oil and gas industry, mainly to downhole geophysical instruments.

BACKGROUND

A known source of plasma-pulse exposure, disclosed in RU 2478780 C1, publ. 04/10/2013. A well-known borehole source of plasma-pulse action contains a ground-based power supply, control and control unit connected by a geophysical cable to a borehole module, which houses: a high voltage multiplier, a capacitor storage of electrical energy, a spark gap with high-voltage and low-voltage electrodes, as well as a feeder for calibrated conductor.

The main disadvantage of the known plasma-pulse source, disclosed in the closest analogue, is the lack of a device for the fastest transfer of the accumulated capacitor storage of electric energy to a spark gap (plasma emitter) with high-voltage and low-voltage electrodes, which reduces the efficiency of plasma formation during the evaporation of a metal conductor and reduces reliability the downhole tool as a whole.

The closest analogue of the claimed invention is a borehole source of elastic vibrations disclosed in RU 2248591, publ. 03/20/2005. The well-known source of elastic vibrations known from the closest analogue comprises a wellbore with an energy storage device, a charger, an arrester with an ignition circuit, an electrohydropulse arrester with two electrodes, and a device for supplying a metal wire to the working interelectrode space.

The disadvantage of the well-known of the closest analogue of the borehole source is the presence of a rather complex air gap with a trigatron ignition circuit. Such a spark gap requires a high voltage initiating pulse, which is supplied by a special high-voltage transformer, for example, an automobile ignition coil (“reel”), to one of its electrodes.

SUMMARY OF THE INVENTION

The objective of the claimed invention is to develop a borehole source of plasma-pulse exposure with increased efficiency of plasma-pulse exposure (TID) on the reservoir, as well as improving the reliability of the device.

The technical result of the invention is to increase the reliability of the downhole source of plasma-pulse exposure.

The specified technical result is achieved due to the fact that the downhole plasma-pulse source contains a housing in which is located a control unit connected to an electric energy storage device and a plasma emitter connected to a metal conductor supply mechanism. At the same time, an electromechanical contactor-discharger containing movable and fixed contacts is installed between the electric energy storage device and the plasma emitter. Moreover, the fixed contact is connected to the high-voltage positive bus of the electric energy storage device, and the movable contact is connected to the high-voltage electrode of the plasma emitter using a flexible insulated conductor.

The movable and fixed contacts are made in the form of a coaxially arranged cone and a cone-shaped sleeve, respectively. The conical surfaces of the contacts are equidistant.

The movable contact is connected to the armature of a retractor type solenoid using a rod made of a dielectric.

The movable contact is equipped with a slider with the possibility of sliding along the guide surface of the thin-walled tray of the contactor-discharger.

The fixed contact is rigidly connected to the base of the contactor-discharger.

The solenoid is connected to the base of the contactor-discharger.

The downhole source housing is configured to be rigidly connected to a cable head containing a geophysical cable and connected to a control unit.

The downhole source housing is configured to be rigidly connected to a centering device.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more clear from the description, which is not restrictive and given with reference to the accompanying drawings, which depict:

FIG. 1 is a general view of a borehole source of plasma-pulse exposure;

FIG. 2 is a longitudinal section of a contactor-arrester;

1 - control unit; 2 - electric energy storage device; 3 - plasma emitter; 4 - high voltage electrode; 5 - low voltage electrode; 6 - metal conductor feed mechanism; 7 - electromechanical contactor-arrester; 8 - centering device; 9 - cable head; 10 - geophysical cable; 11 - casing of a borehole source of plasma-pulse exposure; 12 - the base of the electromechanical contactor-arrester; 13 - solenoid; 14 - fixed contact; 15 - high voltage positive bus; 16 - movable contact; 17 - anchor; 18 - connector; 19 - thrust; 20 - slider; 21 - spring; 22 - flexible insulated conductor; 23 - a lock-nut; 24 - adjusting washers; 25 - thin-walled tray.

DETAILED DESCRIPTION OF THE INVENTION

The downhole source of plasma-pulse action contains a housing (11) in which a control unit (1) is located, connected to an electric energy storage device (2), and a plasma emitter (3) connected to a metal conductor supply mechanism (6). In this case, between the electric energy storage device (2) and the plasma emitter (4), an electromechanical contactor-discharger (7) is installed, comprising a movable (16) and a fixed (14) contact. Moreover, the fixed contact (14) is connected to the high voltage positive bus (15) of the electric energy storage device (2), and the movable contact (16) is connected to the high voltage electrode (4) of the plasma emitter (3) using a flexible insulated conductor (22).

The movable (16) and fixed (14) contacts are made in the form of a coaxially arranged cone and cone-shaped sleeve, respectively.

The conical surfaces of the contacts (14, 16) are equidistant.

The movable contact (16) is connected to the armature (17) of the retractor type solenoid (13) by means of a rod (19) made of a dielectric.

The movable contact (16) is provided with a slider (20) with the possibility of sliding along the guide surface of the thin-walled tray (25) of the contactor-discharger (7).

The fixed contact (14) is rigidly connected to the base (12) of the contactor-discharger (7).

The solenoid (13) is connected to the base (12) of the contactor-discharger (7).

The casing (11) of the downhole source is made with the possibility of hard connection with the cable head (9) containing the geophysical cable (10) and connected to the control unit (1).

The body of the downhole source is made with the possibility of a rigid connection with a centering device (8).

Downhole source of plasma-pulse exposure works as follows.

In accordance with FIG. 1-2 from the ground control panel via a geophysical cable (9) using a control unit (1) and an electric energy storage device (2), voltage pulses are fed to the supply mechanism of a combustible metal conductor (6) until the latter touches the high-voltage electrode (4) ) plasma emitter (3). At the end of the work of the feed mechanism of the combustible conductor (6), a command is sent from the ground panel to increase the voltage and accumulate electric energy in the electric energy storage device (2), which contains capacitors in parallel. Upon reaching the required level of charge of the capacitors, which is controlled by the ground control panel, a command is issued to actuate the solenoid (13), which performs the reciprocating movement of the armature (17) connected to the connector (18) and the thrust (19), which, in turn, move the movable contact (16) with the slider (20) fixed on it and bring it closer to the fixed contact (14). In this case, the contact does not touch. Between the conical surfaces of the contacts a gap of the order of 0.2-0.4 mm is maintained, sufficient for high-voltage breakdown of the air gap in the form of a corona discharge. At the time of the breakdown of the aforementioned air gap, electrical energy is almost instantly introduced into the plasma emitter (3), as a result of which the metal conductor (31) instantly heats up, evaporates, explodes and forms a plasma channel in the interelectrode space of the plasma emitter (3), and shock wave propagating in the borehole fluid and in the skeleton of the reservoir. After the stationary (14) and movable 16 contacts come closer, the latter, by means of the spring 22, returns to its original position, in which a gap is formed between the conical surfaces of the contacts, which ensures that there is no breakdown when the specified potential difference is reached. The fact of electric explosion is recorded by the ground control panel, then the command for supplying the conductor, the accumulation of electrical energy again passes, and the process repeats.

As experiments showed, the transition of electrical energy in the form of a corona discharge between the fixed and moving contacts (14, 16) is characterized by a huge current density of the order of 1-2 kA / mm ² . The area of the mating conical surfaces of the fixed and movable contacts (14, 16) is approximately 4 times larger than the area of similar flat contacts, the diameter of which is equal to the diameter of the base of the cone in the proposed device, which makes it possible to reduce the current density by the same amount. This, in turn, reduces the erosion of the contact material, reduces the likelihood of their melting, which increases the reliability of the device as a whole and the effectiveness of the plasma-pulse impact on the reservoir.

Thus, the present invention allows to obtain a borehole source of plasma-pulse exposure, which allows to increase the reliability of its operation.

The invention has been disclosed above with reference to a specific embodiment. Other specialists may be obvious to other embodiments of the invention, without changing its essence, as it is disclosed in the present description. Accordingly, the invention should be considered limited in scope only by the following claims.

Claims (9)

1. A downhole source of plasma-pulsed exposure, comprising a housing in which a control unit is connected to an electric energy storage device and a plasma emitter connected to a metal conductor supply mechanism, wherein an electromechanical contactor-discharger is installed between the electric energy storage device and the plasma emitter, comprising movable and fixed contacts, the fixed contact being connected to a high voltage positive bus of an electric energy storage device, and the movable The contact via a flexible insulated conductor is connected to the high voltage electrode of the plasma emitter. 2. The downhole source according to claim 1, characterized in that the movable and fixed contacts are made in the form of coaxially arranged cones and conical bushings, respectively. 3. The downhole source according to claim 2, characterized in that the conical surfaces of the contacts are equidistant. 4. The downhole source according to claim 2, characterized in that the movable contact is connected to the armature of a retractor type solenoid using a rod made of a dielectric. 5. The downhole source according to claim 2, characterized in that the movable contact is provided with a slider so that it can slide along the guide surface of the thin-walled tray of the contactor-discharger. 6. The downhole source according to claim 2, characterized in that the fixed contact is rigidly connected to the base of the contactor-discharger. 7. The downhole source according to claim 4, characterized in that the solenoid is connected to the base of the contactor-discharger. 8. The downhole source according to claim 1, characterized in that the downhole source housing is configured to be rigidly connected to a cable head containing a geophysical cable and connected to a control unit. 9. The downhole source according to claim 1, characterized in that the downhole source housing is configured to be rigidly connected to a centering device.

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