RU71045U1 - PROTECTOR OF SUBMERSIBLE OIL-FILLED ELECTRIC DRIVE OF A Borehole CENTRIFUGAL PUMP - Google Patents

Abstract

The utility model relates to petroleum engineering, namely to protectors with an elastic diaphragm used in submersible oil-filled electric motors of borehole centrifugal pumps. The upper mechanical seal is made according to a double circuit with an opposite arrangement of bellows and is located in a chamber protected from ingress of formation fluid. The chamber has at least two openings, one of which is located in the upper part of the chamber and connected by a channel to the external outlet of the hydraulic protection, and one is located in the lower part of the chamber and communicates with the water-lock chamber. The camera communicates with the inner water seal chamber through a channel, the lower part of which is formed by a tube, the outlet of which is located in the lower part of the inner cavity. The aforementioned cavity is connected through an opening in its upper end part to the annular channel, which is located below the chamber with the mechanical seal. The technical result when using this tread is to increase efficiency and extend the life of a submersible oil-filled electric motor. 1 s.p. 1 ill.

Description

The utility model relates to petroleum engineering, namely to designs of protectors with an elastic diaphragm. The tread is used in a borehole centrifugal pumping unit to ensure reliable and continuous operation of a submersible oil-filled electric motor. It prevents the formation fluid from entering the motor cavity, compensates for oil leakage from the electric motor, aligns the internal pressure in the engine with the formation fluid pressure in the well.

A device is known for hydroprotection (protector) of a submersible oil-filled electric motor (see RF patent No. 2194349, published 2002.12.10), consisting of a housing, a shaft, an upper chamber, a diaphragm is sealed that separates the chamber into a diaphragm and a hydrolock chamber. In the upper part of the hydraulic protection there is a double mechanical seal in a separate chamber. The disadvantage of this system, in particular, in the tread is not provided for an effective system for removing gas from the chamber with mechanical seal during operation of the pump. Therefore, during the operation of the pump, a gas mixture accumulates in this chamber. This leads to a decrease in the life of the mechanical seal.

The closest analogue of the claimed utility model is the tread of a submersible oil-filled electric motor (see RF patent RU No. 2118033, published on 08/20/1998). It contains: in the upper part of the tread, a gas outlet channel with an outlet that is closed by a plug and an end seal, a shaft, a cavity around the shaft, the walls of which are formed by the surfaces of the shaft and the inner surface of the shell surrounding the shaft, an elastic diaphragm, a housing, an external diaphragm filled with reservoir fluid a cavity and a water lock chamber hermetically separated by an elastic diaphragm. The cavity around the shaft is connected to a water lock chamber. These cavities and a water lock chamber are located below the above mechanical seal. Gas is removed when the engine is filled through a gas outlet channel with an outlet, which is closed by a plug. The disadvantages of this device include the fact that most of the upper mechanical seal is in direct contact with the reservoir fluid, and in the event of formation fluid getting into the hydraulic chamber, the reservoir fluid

almost immediately enters the annular channel. This leads to a decrease in the resource of hydroprotection.

The technical result of the claimed technical solution is to increase the working resource, in particular, by extending the service life of the radial and axial bearings of the tread and its seals.

This technical result is achieved due to the fact that a protector of a submersible oil-filled electric motor has been developed, comprising a housing, in the upper part of which there is a mechanical seal and a gas outlet channel with an outlet that is closed by a plug, a shaft with bearings, an annular channel around the shaft, the walls of which are formed by the shaft surfaces and the inner surface of the shell surrounding the shaft, the diaphragm cavity and the hydraulic seal chamber filled with the reservoir fluid, hermetically separated by an elastic a diaphragm different from the known one in that the tread in the upper part contains an additional gas outlet channel with at least one gas outlet valve at the outlet of the channel, a chamber with an end seal is located above the diaphragm cavity and the gas seal chamber, which is doubled with opposed bellows, the chamber with the above the seal has at least two openings, one of which is located in the upper part of the chamber and is connected by a channel to the aforementioned outlet ra, and the other is located at the bottom of the chamber and communicates with the water lock chamber. An additional opening may be made in the upper part of the chamber, which communicates with a part of the channel of the additional gas valve located below the gas valve. The hole in the lower part of the chamber with the aforementioned seal can communicate with the water-lock chamber through a channel, the lower part of which is formed by a tube, the outlet of which is located in the lower part of the water-lock chamber, hydraulically connected through the channel in its upper part to the annular channel, which is located below the chamber with the end seal. In the upper part of the chamber, an additional opening may be made, which communicates with a part of the channel of the additional gas outlet valve located below the gas valve, while the hole in the lower part of the chamber with the above seal can communicate with the gas seal chamber through the channel, the lower part of which is formed by a tube, the outlet which is located in the lower part of the hydraulic lock chamber, hydraulically connected through a channel in its upper part with an annular channel, which is located below the chamber with rtsevym seal.

Labyrinth protection and the presence of at least two gas vents in the upper part of the chamber with a double mechanical seal ensure the achievement of the specified technical result. The specified system of gas removal through the gas outlet channel allows to reduce the likelihood of gas entering the upper bearing units of the tread (radial and axial bearings), and accordingly increase the operating time. The gas outlet through the upper opening to the gas outlet channel during operation of the pump allows for more efficient operation of the double mechanical seal - to avoid the undesirable regime of dry gas friction in the seal with subsequent rapid destruction of the seal (which, obviously, reduces the resource of this type).

Figure 1 shows a General view of the tread of a submersible oil-filled electric motor.

The tread has the following design. The upper heel 20 and the upper radial bearing 14 are fixed on the tread shaft, a chamber 3 (protected against ingress of formation fluid) with a double mechanical seal 2 is located lower on the shaft, then radial bearings and heel 21 are fixed down the shaft, and mounted on the lower end of the tread shaft radial bearings 22.

In the upper part of the tread contains a gas outlet channel 13, the upper end of which contains a gas valve 17. The valve 17 is designed to relieve pressure and exhaust gas generated during operation of the pump, for example, penetrated from the reservoir fluid through the rubber diaphragm of the tread. The upper part of the tread also contains a channel 18 with an external technological outlet 19 (for gas discharge during refueling with an electric motor, it is closed with a plug during operation in the well).

The openings 10, 16 are made in the upper part of the chamber 3. The opening 10 is connected to the channel 18, the upper end of which is connected to the opening 19, and the opening 16 communicates with the channel cavity of the gas valve 13 located below the gas valve (or there may be two sequential gas valves - not shown in Fig.). In the lower part of the chamber 3 there is a lower outlet 11, which has an exit to the channel connected to the hydraulic lock chamber 5. This cavity is hermetically separated from the external cavity (filled with formation fluid) by an elastic diaphragm 8 located in the tread case 7. The channel, part of which is formed by a tube 4 (for example, made of brass), connects the chamber 3 with the cavity 5. The lower end of the tube 15 is displayed in the lower part of the chamber 5. On the upper end surface of the water-lock chamber contains a channel 6,

connected to the annular channel. This channel, formed by the surface of the shaft 1 and the inner surface of the cylindrical shell 9, covering the shaft 1, is located below the chamber 3 with mechanical seal.

The protection mechanism of the engine from the reservoir fluid and the effective removal of gas from the cavity of the chamber with a double mechanical seal works as follows. The gas generated during operation from the chamber 3 through the channel 13 is discharged through the gas valve 17 into the annulus.

The device implements one of the mechanisms of labyrinth protection (the direction of movement of the reservoir fluid is indicated by arrows). When a leak occurs in the mechanical seal, the formation fluid enters the chamber 3. The formation fluid can enter the internal cavity 5 when it enters the chamber 3 through the tube 4. At the first stage, in the event of a leak in the upper mechanical seal, the formation fluid accumulates (as denser than oil, liquid) in the lower part of the internal cavity. The formation fluid, gradually accumulating in the hydraulic lock chamber 5, reaches the channel 6. The next stage of the formation fluid advancement is its entry into the annular channel 12 (the cavity around the shaft). It does not occur immediately upon penetration into the internal cavity 5, but after a considerable period of time (comparable with the characteristic time of the well’s operation) after filling the upper cavity with formation fluid to a level exceeding the level of the hole on the upper end part - the entrance to the channel 6, which is connected with the annular channel.

Claims (4)

1. The protector of a submersible oil-filled electric motor, comprising a housing, in the upper part of which there is a mechanical seal and a gas outlet channel with an outlet closed by a plug, a shaft with bearings, an annular channel around the shaft, the walls of which are formed by the surfaces of the shaft and the inner surface of the shell surrounding the shaft to be filled formation fluid, the diaphragm cavity and the water-tight chamber, hermetically separated by an elastic diaphragm, characterized in that the tread in the upper part contains up to filling gas channel with at least one gas valve at the channel outlet, above the diaphragm cavity and the gas seal chamber there is a chamber with an end seal that is doubled with opposed bellows, the chamber with the above seal has at least two openings, one of which is located in the upper part of the chamber and is connected by a channel with the external outlet of the tread, and one is located in the lower part of the chamber and communicates with the water-lock chamber. 2. The tread according to claim 1, characterized in that an additional hole is made in the upper part of the chamber, which is in communication with a part of the channel of the additional gas valve located below the gas valve. 3. The tread according to claim 2, characterized in that the hole in the lower part of the chamber with the aforementioned seal communicates with the water-lock chamber through a channel, the lower part of which is formed by a tube, the outlet of which is located in the lower part of the water-lock chamber, hydraulically connected through a channel in its upper parts with an annular channel, which is located below the chamber with mechanical seal. 4. The tread according to claim 1, characterized in that an additional hole is made in the upper part of the chamber, which is communicated with a part of the channel of the additional gas vent valve located below the gas valve, and the hole in the lower part of the chamber with the above seal communicates with the water seal chamber through the channel, the lower part of which is formed by a tube, the outlet of which is located in the lower part of the water-lock chamber, hydraulically connected through a channel in its upper part with an annular channel, which is located below the chamber with mechanical seal.