RU2734286C1 - Valve for liquid pumping into well - Google Patents

Abstract

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to oil industry and can be used for removal from cavities of electric-centrifugal pumps and tubing string of various types of precipitation, for example inorganic salts, solid suspended particles of sand, asphalt-resinous and other substances. Valve for pumping liquid into the well comprises a housing with upper and lower connection threads, a shutoff element in the form of a ball, a spring with a force regulator of its compression, fixed hollow rod in the form of cylindrical support with through radial channels for flow of liquid from the tubing string, a ball travel limiter. Inside the stepped cylindrical support there is a hydraulic flow distributor with through radial and vertical channels which are not crossed between each other. Radial channels of hydraulic control valve are interconnected with radial channels of cylindrical support and interconnected by central vertical channel covered in lower end by additional spring-loaded ball. Outer surface of upper stage of cylindrical support is made with diameter smaller than inner diameter of valve body.

EFFECT: technical result is improved reliability of valve operation in conditions of presence of solid suspended particles in production and possibility of sediments removal from submersible equipment using small volumes of chemical reagents.

1 cl, 2 dwg

Description

The proposed invention relates to the oil industry and can be used to remove various types of sediments from the cavity of electric centrifugal pumps and tubing strings, for example, inorganic salts, solid suspended particles of sand, asphalt-resinous and other substances.

With the formation of sediments in the tubing and the cavity of the electric centrifugal pump, a decrease in pump flow occurs due to a significant increase in resistance in the submersible equipment and an emergency occurs.

At the outlet of the electric centrifugal pump (ESP), check and whipping valves are installed in the tubing. When the pump is stopped, the check valve prevents the outflow of liquid from the tubing string into the well and the pump shaft unwinding in the opposite direction. The churning valve allows, on the contrary, to release the tubing from fluid for lifting equipment during repair (Bogdanov A.A. Submersible centrifugal electric pumps for oil production. M .: Nedra. 1968. S. 52-54).

Known check valve (patent RU No. 56940 U1, declared. 07.04.2006, publ. 27.09.2006), consisting of a body, a saddle fixed in the body, a shut-off element in the form of a ball. A cylindrical channel and a stop for the axial movement of the shut-off element in the channel with openings for the fluid flow are formed in the housing, and the stop is integral with the housing. The axes of the holes for the fluid flow are located on the generatrices of the cylindrical channel. The saddle is secured at the inlet with a nut and / or a threaded bushing with keyways.

Known valve of a borehole centrifugal pump (patent RU 72268 U1, filed. 12/26/2007, publ. 10/04/2008), containing a housing with internal and external connecting threads and a saddle fixed in it and placed in the channel of the axial movement limiter ball locking element. The valve seat is equipped with a bore for the sealing ring and is fixed with respect to the body by a cylindrical bushing and a washer with holes for the passage of formation fluid. In the upper part of the valve body there is a branch pipe with a sludge trap pipe screwed into it, equipped with radial holes for the formation fluid passage. A washer with holes for the passage of formation fluid is fixed against axial movement relative to the valve body by means of a spring ring, and the branch pipe is mounted in the body by means of a key with a spring ring.

A common disadvantage of the above analogs is the impossibility of removing various sediments from the tubing cavity and the electric centrifugal pump by pumping various chemicals or coolant into the well through the tubing string and then a submersible pump.

Known cleanable downhole filter (patent RU 2441139 C1. Appl. 12.07.2010. Publ. 27.01.2012), including outer and inner pipes with holes, a filter element fixed between the pipes, a wave converter. The filtering element is made in the form of a wire twisted along the height. The wave converter is made in the form of a compression spring.

To clean the filter after clogging, the centrifugal pump is stopped and then started in the opposite direction of the rotor rotation. The backflow of the liquid washes away the adhered sand particles from the filter element.

This device has the disadvantage that it is impossible to create a reverse flow of fluid from the tubing through the pump into the well in the case of a check valve at the outlet of the centrifugal pump.

A known check valve for an electric centrifugal plant and a method for cleaning the filter at the pump intake (patent RU No. 2544930 C1. Check valve for an electric centrifugal plant and a method for cleaning the filter at the pump intake. Appl. 17.09.2013. Publ. 16.02.2015). The design of the valve includes a poppet valve stem made of a hollow, a movable sleeve made of stepped, the lower part of which with a smaller diameter forms a sliding friction pair with the outer surface of the hollow valve stem, and in the upper part of the sleeve there are horizontal holes with larger diameters in comparison with the valve stem holes.

Flushing is performed by lowering the load into the pipe string on a scraper wire through a lubricator at the wellhead, which by its own weight compresses the spring and moves the movable step-shaped sleeve downward, aligning the horizontal holes in the movable sleeve and the hollow poppet valve stem and creating a fluid overflow under hydrostatic pressure from the string pumping - compressor pipes into the well through the pump cavity and filter, and after washing the filter, the load is removed from the well and the pump is started up.

The disadvantage of this method is the need to lower the load on a scraper wire to the valve through the tubing string. A well with bent holes or its inclination does not allow lowering the load through the tubing under its own weight. On the other hand, the presence of any deposits (salts, paraffin) on the tubing wall also impedes the descent of the load.

Closest to the proposed invention is a three-position check valve, containing a body with upper and lower connecting threads (Patent RU 104618 U1. Three-position check valve. Applied 25.01.2011. Published 20.05.2011. BI No. 14). The valve body is made of composite and has a top, middle and bottom. The hollow rod is fixed inside the body motionlessly, the upper part of the rod is made in the form of a seat for a ball, and through radial channels are made on it under the seat.The movable element is a hollow piston located on the outer generatrix of the hollow rod.

To remove deposits, the solvent is pumped into the cavity of the tubing string. When the design pressure above the valve is reached, the movable piston overcomes the spring force, moves down and opens the radial channels of the hollow stem. When the holes are aligned, the liquid from the tubing enters the pump and cleans it of various deposits. In the case of deposits in tubing, the injected liquid (solvent) removes wax, tar, etc. deposits from their inner surface. After processing, the excess pressure is relieved. The movable piston is returned to its original position by the spring.

The valve, chosen as a prototype, has the disadvantage of jamming the movable piston when mechanical impurities enter the gap of the rubbing pair. The produced well products always contain solid particles of rocks carried out from the formation by the produced products.

The technical task of the proposed solution is to improve the reliability of the valve in the presence of suspended solids in the produced product.

The problem is solved by the fact that in the known solution, which includes a body with upper and lower connecting threads, a locking element in the form of a ball, a spring with a regulator of its compression force, a stationary hollow rod in the form of a cylindrical support with through radial channels for fluid flow from the tubing, a limiter the movement of the ball, according to the invention, inside the cylindrical support, made stepwise, there is a hydraulic flow valve with through non-intersecting radial and vertical channels, its radial channels are communicated with the radial channels of the cylindrical support and are interconnected by a central vertical channel, blocked at the bottom end by an additional spring-loaded ball , and the outer surface of the upper stage of the cylindrical support is made with a diameter smaller than the inner diameter of the valve body.

FIG. 1 and 2 show the valve layout. A stepped cylindrical support 3 with a seal 4 in the lower step and a retaining ring 5. In the lower part of the upper step of the support 3, radial channels 6 are made in the body 1 with the lower 2 and the upper (not shown in the figure) threaded connections. The upper end part of the support 3 overlaps the ball 7, above which the limiter of its movement 8 with through windows is located 9. The hole in the upper end of the support 3 forms a landing seat for the ball 7. Inside the cylindrical support 3, a hydraulic flow distributor 10 with through radial channels 11 aligned with the radial channels 6 of the support is sealed 3. The channels 11 are connected to the vertical channel 12, the lower end of which is made in the form of a saddle and is closed by an additional ball 13, supported by a spring 14. The ball 13 with a spring 14 are located in the body 15 with through channels 16. In the body 15 there is an adjusting bolt 17 s from below movable plate 18.

Through vertical channels 19 are made in the body of the flow valve 10. The flow valve 10 is held in the inner cavity of the support 3 by a lock nut 20 with a threaded connection.

The valve is installed in the lower part of the tubing string directly above the electric submersible pump (not shown in the figure).

The valve works as follows.

In the normal operation of a submersible electric centrifugal pump, the produced production of the formation after exiting the pump passes through the vertical channels 19 of the hydraulic valve of flows 10, and lifting the ball 7 under the action of the pressure, enters the tubing string through the windows 9 (shown by solid arrows in Fig. 1).

With the formation of sediments in the tubing string or in the working bodies of a submersible electric centrifugal pump, for example, inorganic salts or mechanical impurities with asphalt-resin-paraffinic substances, a significant decrease in its supply occurs, as evidenced by data on well flow rate measurement.

To remove sediments, the well is stopped by turning off the submersible motor. After stopping, the ball 7, under its own weight, sits in the saddle and blocks the discharge of liquid from the tubing string into the well through the pump working bodies.

Further, the calculated volume of the sediment solvent is pumped into the tubing string under excess pressure. The solvent through the radial channels 6, 11 and the vertical channel 12 under excess pressure pushes the spring-loaded ball 13 down and enters the pump through the through channels 16 (shown by dashed arrows). After the calculated volume of the solvent has been injected, the injection is stopped and the time required for the dissolution of the sediments in the tubing string or the pump cavity is delayed. Next, the pump is started up. The well product, lifting the ball 7, will begin to flow into the tubing string and pumped out to the surface into the oil gathering system.

To ensure trouble-free operation of the pump and the efficiency of removing sediments, the spring 14 is adjusted by the bolt 17 in such a way that when the pump stops, the ball 13 hermetically closes its seat. To inject the solvent into the tubing string at the wellhead, it is necessary to additionally raise the pressure to the calculated value at which the ball 13 will depress the spring 14 and begin to pass through the liquid.

Injection of solvents directly into the tubing string significantly reduces reagent consumption compared to injection of reagents through the annulus of the well.

When sediments of mechanical impurities accumulate on the filter and in the receiving part of the pump, the pump is simply flushed with the pumped liquid without the use of chemicals.

The technical and economic advantages of the invention are the simplicity and reliability of valve opening, as well as the ability to remove sediments from submersible equipment using small volumes of chemicals.

Claims (1)

A valve for pumping liquid into a well, including a body with upper and lower connecting threads, a ball-shaped shut-off element, a spring with a compression force regulator, a stationary hollow rod in the form of a cylindrical support with radial through channels for fluid flow from the tubing string, ball displacement limiter, characterized in that inside the cylindrical support, made stepwise, there is a hydraulic flow valve with through non-intersecting radial and vertical channels, its radial channels are communicated with the radial channels of the cylindrical support and are interconnected by a central vertical channel, blocked at the bottom end by an additional a spring-loaded ball, and the outer surface of the upper stage of the cylindrical support is made with a diameter smaller than the inner diameter of the valve body.

Images