RU2641762C1 - Submersible oil extraction unit with plunger pump - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: submersible oil extraction unit with a plunger pump comprises a reducer, a hydro-protected electric motor, a drive shaft of which is connected to a screw of ball-screw pair located in reducer body and connected with a rod of the pump drive, which is sealed in the body and connected to the nut by means of a hollow rod embracing the screw, dampers installed in lower part of reducer body, and a control station. In the upper part of the reducer body, there is a jamming chamber, which allows to avoid pulsations of pressure when the plunger moves, before which damping devices are installed. The control station is equipped with a control unit of the stroke of the ball-screw pair nut, which ensures the unstressed reverse of the nut.

EFFECT: increased reliability of the unit operation.

2 cl, 1 dwg

Description

The invention relates to the field of oil production and can be used to lift well fluid.

Known surface installation of a sucker rod pump containing an electric motor kinematically connected by a two-way screw-nut with a rod string [Patent No. 2133875 of the Russian Federation, F04B 47/02, publ. July 27, 1999]. When the screw-nut is rotated, the rod string of the submersible plunger pump reciprocates in the axial direction and drives the piston of the plunger pump.

Disadvantages of installation:

1. The column of rods limits the depth of descent of the plunger pump, as well as the reliability of the pump installation, since with increasing length, and hence weight, the column of rods increase tensile stresses, which leads to breakage of the rods and failure of the installation.

2. Low installation efficiency due to high slip friction losses in the screw-nut gear.

3. The presence in the ground part of the installation of reinforced concrete foundations, significantly increasing the cost of the entire installation.

Also known is a surface installation of a borehole plunger pump [US Patent No. 5,404,767, 1993], comprising at least two parallel-mounted ball screw rod drives from a reversible electric motor. The drive nuts connected by a traverse to a polished rod perform a reciprocating motion. The screws are connected to the electric motor and protected from the environment by corrugated elastic shells. At the upper and lower points of the housing, limit switches are installed to switch the reverse of the electric motor, as well as emergency voltage relief switches.

The disadvantages of the installation include the use of limit switches for reverse control associated with a separate electrical line laying, which reduces the reliability of the unit as a whole; the presence of a string of rods, limiting the depth of the descent of the pump and reducing reliability, as well as the need to build a foundation, leading to an increase in the cost of the entire installation.

The closest technical solution (prototype) is an oil submersible installation with a plunger pump, which includes a gearbox, an elastic shell, a reversible electric motor with hydroprotection, the drive shaft of which is connected to the screw of a ball screw located in the gearbox housing and connected to the pump drive rod, connected to the ball screw nut pairs through a hollow rod, covering the screw and included with it in a movable connection [Patent No. 2347947 of the Russian Federation, F04B 47/06, publ. 02/27/2009]. The internal cavities of the casing and the elastic shell are filled with oil, and the outer surface of the shell communicates with the cavity of the well, and dampers are installed in the lower part of the screw of the ball screw pair and on the hollow stem. The electric motor is connected to a ground control station.

Design disadvantages:

1. When the plunger moves, a pressure differential occurs in the seal of the plunger rod, which leads to oil leaks used to lubricate the screw-nut gear. This problem is not solved by the use of the corrugation proposed in the patent to eliminate this drawback, because corrugation has a limited resource of work.

2. The spectrum of oscillations that occur when the nut hits the damper has a wide range of frequencies. If one of the frequencies coincides with the resonant one, fatigue failure of the installation units is possible.

An object of the invention is to increase the reliability of the submersible installation by damping the differential pressure in the seal of the plunger rod and shock-free reverse of the nut.

The specified technical result is achieved by the fact that in a submersible oil production installation with a plunger pump containing a gearbox, a hydraulic motor with a drive shaft connected to a screw of a ball screw located in the gearbox housing and connected to a pump drive rod connected to the ball screw nut by a hollow rod covering the screw, dampers installed in the lower part of the gear housing and ground control station, according to the invention, in the upper part of the gear housing is placed cam A silencing measure that avoids pressure pulsations when the plunger moves, in front of which dampers are installed.

To ensure shock-free reverse of the nut, the control station is equipped with a nut stroke control unit.

Submersible oil production plant with a plunger pump is shown schematically in the drawing.

The installation comprises sequentially installed plunger pump 1 having inlet openings 2, gearbox 3, hydraulic protection 4 and electric motor 5. Electric motor 5 is connected by cable to the control station 6 located on the surface.

The gearbox 3 is a unit consisting of an oil-filled casing, in the upper part of which there is a silencing chamber 7, and a ball screw 8, including a movable nut 9 and a working screw 10. The shaft 11 of the electric motor 5 is connected to the working screw 10 through the shaft 12 of the hydraulic protection 4. nut 9, moving along a guide 14 mounted in the gear housing 3, provides longitudinal movement of the hollow rod 13 with which it is connected and which moves outside the rotor. The hollow rod 13 is connected by a polished rod 15 to the plunger pump 1. In the silencing chamber 7, the rod 15, which performs reciprocating movements, is sealed with ring seals 16, which are placed on the outer sides of the bases of the chamber 7. For dissipation of impact energy when nut 9 is reversed the lower part of the housing of the gearbox 3 and in front of the jamming chamber 7 mounted dampers 17, which may contain elastic elements. The control station 6 is equipped with a nut stroke control unit, it can be made in the form of software.

The hydraulic protection 4 is similar in design to that used in installations with centrifugal pumps and is equipped with a double-acting axial bearing 18, in which the thrust bearing consists of segments. In the upper part of the hydroprotection 4, a chamber 19 is formed, which is designed to prevent differential pressure and protect against the ingress of fur. impurities in the electric motor.

Installation works as follows.

The rotation of the shaft 11 of the electric motor 5 is transmitted by the intermediate shaft 12 of the hydraulic protection 4 to the working screw 10 of the ball screw 8. When the screw 10 is rotated, longitudinal movement along the guide 14 of the movable nut 9 and the hollow rod 13 connected to it occurs to the upper or lower position. The rod 13 moves the plunger of the pump piston 15 by the rod 15. When the plunger moves upward, fluid is pumped through the inlets 2. The silencing chamber 7, due to the seal resistance 16 and due to the compressibility of the fluid, suppresses the pressure pulsations generated during the movement of the plunger, which avoids oil leakage . When the electric motor 5 is first turned on, the nut 8 travels up and down with touching the upper and lower dampers 17. At the moment of contact, the current value of the electric motor 5 changes, which is fixed in the nut stroke control unit, which is part of the control station 6. By changing the motor current in Moments of contact determine the time the nut travels from the upper to the lower dampers. It is remembered and the further course of the nut is determined by this time minus the small value of E , so that further work is done without touching. The stroke time of the nut is corrected if a touch signal comes back to the control unit.

Claims (2)

1. Submersible oil production plant with a plunger pump, comprising a gearbox, an electric motor with hydraulic protection, the drive shaft of which is connected to the screw of the ball screw located in the gearbox housing and connected to the pump drive rod, connected to the ball screw nut by means of a hollow rod covering the screw, dampers, installed in the lower part of the gear housing, and a control station, characterized in that in the upper part of the gear housing there is a silencing chamber to avoid pressure pulsations during movement the plunger, in front of which dampers are installed. 2. The submersible installation according to claim 1, characterized in that the control station is equipped with a ball screw nut control unit for the ball screw providing shock-free reverse of the nut.

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