RU2811050C1 - Tubing string extension - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention is intended for downhole oil production using submersible pump installations; it can be used to lengthen a tubing string to ensure reciprocating movement of submersible equipment inside the well. The tubing string extension contains a housing, inside of which a hollow movable rod, a spring and separating elements are coaxially located, and an adapter for connection to the tubing string is installed. An electrical line in the form of a spiral is laid outside along the body. A piston is attached to the hollow movable rod. Inside the piston there is a coaxially located through hole for supplying liquid pumped by the pump. On the outer side of the piston there are at least two guide grooves for limiting screws screwed into the outer side of the housing. In the annular gap between the movable rod and the body, seals are placed to separate the internal cavity of the device and the annulus. The separating elements are installed between the spring and the seals in the specified annular gap. The tubing string extension is designed to be connected to the tubing string in the upper part using an adapter, and in the lower part the tubing string is connected to a hollow movable rod.

EFFECT: elongation of the tubing string and controlled reciprocating movement of submersible equipment inside the well during oil production using submersible pump installations are provided while simplifying the design of the extension.

1 cl, 3 dwg

Description

The invention relates to the oil industry, is intended for downhole oil production using submersible pump installations, and can be used to lengthen a tubing string to ensure reciprocating movement of submersible equipment inside the well.

An axial compensator is known [patent RU No. 2558833 C1, IPC E21B 17/07, publ. 08/10/2015], consisting of a core, a body, which is rigidly connected to a nipple by a thread, a collet attached to the body, and a bushing. The compensator also contains shear screws and a split retaining ring. The threaded tabs of the collet engage with the threads made on the core. They are locked by a sleeve, which is fixed to the core by shear screws located in its radial holes. The split retaining ring is made in the form of a ratchet and has a row of teeth on the inner surface that interact with the counter teeth located on the outer surface of the core. This allows the ring to move with the sleeve along the core in only one direction, preventing the subsequent return of the sleeve to its original position. The section of the core in contact with the nipple and the body has edges on the inner surface, thanks to which torque is transmitted from the tubing string to the nipple through mating edges on its outer surface. These edges are located along the entire length of the core stroke relative to the nipple, which allows rotation to be transmitted to equipment located below the compensator. The compensator also has a stop for the sleeve, made in the form of a nut screwed onto the core. The compensator is lowered into the well together with other equipment on the tubing string. When an excess pressure equal to the magnitude of its opening pressure is created in the internal cavity of the compensator, due to the difference in cross-sectional areas of the upper and lower parts of the bushing, the resulting force acting on the bushing is directed upward. This causes the screws to shear and the split retaining ring sleeve to move up the core to its highest position until it stops. As a result of the movement of the sleeve, the threaded ends of the petals of the collet, which is connected to the body, are released. This creates the possibility of moving the core along the nipple with the body. Under the influence of the tensile load that occurs in the tubing string when excess pressure is created in its internal cavity, to operate hydraulically controlled equipment, the threaded ends of the collet petals are elastically released and the core moves along the nipple. As a result of this, the compensator telescopically opens, increasing its length, and thus compensates for the amount of stretching of the tubing string. This allows you to relieve the stress that has arisen in the tubing string.

The disadvantages of the known device are the absence of elastic elements and, accordingly, the impossibility of reverse compression of the compensator after its opening, that is, the inability to control the position of the moving parts of the device relative to each other; complexity of the device design.

The closest in purpose and set of features to the claimed invention is the known device [patent for PM No. 174333 of the Russian Federation, IPC E21B 17/07, publ. 10/11/2017] – a compensator for thermobaric changes in the length of a pipe string with damping of longitudinal vibrations, which was adopted as a prototype. The compensator contains a housing consisting of two pipes connected in series using a coupling, which is the lower stop for the springs, between which separating rings can be located and which are coaxially located inside the housing around the movable rod. Stock

consists of two pipes connected by a coupling, which is made with the possibility of translational movement in the body and is the upper stop for the springs, an end coupling screwed onto the lower pipe, which is also made with the possibility of translational movement in the body. A sub is screwed onto the body on top, which limits the travel of the compensator and inside which the rod moves freely in the axial direction, and on the bottom is a sub for connecting to the tubing string, in which there is a hole and a groove for the outlet of the electrical line and on which a casing is screwed to protect the electrical line. The electrical line is made in the form of a spiral and is laid inside the housing and the movable rod.

The features of the prototype, which coincide with the essential features of the claimed invention, are a housing, inside of which a hollow movable rod, a spring and separating elements are coaxially located, an adapter is installed for connection to a tubing string, and an electrical line in the form of a spiral is laid along the housing.

The disadvantages of the known prototype device include the following.

When installing a compensator in a well, it is impossible to control the position of the moving parts of the device relative to each other and ensure controlled reciprocating movement of the connected submersible equipment to a given value in the well. The absence of sealing seals separating the space inside the device body and the annular space causes leaks to occur. Placing a cable line made in the form of a spiral inside the device body complicates its design, as it necessitates sealing the inlet and outlet holes for the cable line in the compensator body.

The objective of the invention is to provide extension of the tubing string and controlled reciprocating movement of submersible equipment inside a well during oil production using submersible pump installations while simplifying the design of the extension.

The problem is solved due to the fact that in the known device containing a housing, inside of which a hollow movable rod, a spring and separating elements are coaxially located, an adapter is installed for connecting to a string of tubing pipes, while an electrical line in the form of a spiral is laid along the housing, according to invention a piston is connected to the hollow movable rod, inside of which there is a coaxially located through hole for supplying liquid pumped by the pump; on the outer side of the piston there are at least two guide grooves for limit screws screwed in from the outside of the housing, while in the annular gap between the movable rod and the housing to separate the internal cavity of the device and the annulus, seals are placed, separating elements are installed between the spring and the seals in the specified annular gap, and the electrical line is laid outside along the extension body, while the extension of the tubing string is configured to be connected to the tubing string. compressor pipes in the upper part using an adapter, and in the lower part the tubing column is connected to a hollow moving rod.

The features of the proposed technical solution are distinctive from the prototype - the device contains a piston attached to a movable rod, inside of which there is a coaxially located through hole for supplying liquid pumped by the pump; on the outer side of the piston there are at least two guide grooves for limiting screws screwed into the outer side of the housing; seals are placed in the annular gap between the movable rod and the body to isolate the internal cavity of the device and the annulus; separating elements are installed between the spring and the seals in the specified annular gap; the electrical line is laid outside along the extension cord body; The tubing string extension is designed to be connected to the tubing string in the upper part using an adapter, and in the lower part the tubing string is connected to a hollow movable rod.

Placing a piston with a through hole inside the body of the inventive device, connected to a hollow movable rod, ensures the extension of the hollow rod when the pressure in the tubing string increases, for example, when the flow line valve at the wellhead is partially or completely closed when operating a submersible pumping unit. When the pressure in the tubing decreases to a certain operating value, under the action of a spring, the movable rod with a fixed piston, inside of which a coaxial through hole is made, returns to its original position (the rod retracts). Thus, controlled reciprocating movement of the submersible equipment connected to the extension along the production string of the well is ensured.

The presence on the outer side of the piston of at least two guide grooves for limiting screws screwed into the outer side of the housing ensures that the amount of reciprocating movement is limited and the rotation of the piston and the movable rod attached to it is prevented.

Placing seals in the gap between the movable rod and the housing ensures separation of the internal cavity of the device and the annular space, that is, the tightness of the extension when it is connected to the layout of the downhole pumping equipment.

Installation of separating elements between the spring and the seals ensures uniform transmission of compressive force from the spring to the seals and protects the seals from mechanical damage by the spring.

Laying the electrical line outside, along the body, simplifies the design of the proposed device.

The essence of the claimed invention is illustrated by the drawings presented in Fig. 1-3.

In fig. Figure 1 shows a longitudinal section of the column extension.

In fig. Figure 2 shows a cross section of the column extension.

In fig. Figure 3 shows the installation of an electric centrifugal pump (ESP), which includes a column extension.

The essence of the invention lies in the fact that the inventive tubing string extension (Fig. 1) consists of a hollow body1, to which the adapter is connected2. Inside the case1 a hollow movable rod is located coaxially3 with piston4. Piston4 rigidly connected to the movable rod3, for example, by means of screws5. Piston4 made with a through coaxial hole6. In the annular gap7 between the body1 and movable rod3 coaxially installed seals8 and separating elements9, between which a spring is mounted10, consisting, for example, of separate ring-type sections.

The deformation of the spring 10 occurs during the reciprocating movement of the hollow rod 3 with the piston 4 . The amount of movement is limited by the length of at least two guide grooves 11 and limit screws 12 . The grooves 11 and limit screws 12 are placed in the section of the housing 1 through equal angular displacements (Fig. 2).

To adapter2 (see Fig. 1) and rod3 sections of the tubing string are connected13. Along the body1 of the proposed extension cord, an electrical line is laid14 in the form of a spiral fixed to the surface of the body1 and tubing13 by means of fasteners (clamps)15. The inventive extension is lowered into the production string 16 of the well, for example, as part of the installation layout of an electric centrifugal pump (Fig. 3). In this case, the adapter 2 The extension is connected to the tubing string 13. Below the extension is an electric centrifugal pump17 with an upstream device, e.g. with a self-cleaning input filter18described in the patent [Patent RU No. 2715774 C1, IPC E21B 43/08, publ. 03/03/2020]. When performing reciprocating motion along the production string16 the permeability of the filter element is restored (cleaned)18. Pump drive17driven by a submersible electric motor19.

The inventive device is installed in a well as part of a submersible pumping unit and operates as follows.

When the submersible electric motor 19 starts, the rotor of the electric centrifugal pump 17 begins to rotate. In this case, the pump 17 is started with the valve on the flow line at the wellhead closed (not shown in Fig. 3). Inside the tubing string 13 , inside the housing 1 of the inventive extension (see Fig. 1) and the internal channel of the hollow rod 3 , excess pressure is created acting on the piston 4 . The pressure acting on the piston 4 causes the compression of the sections of the spring 10 installed in the annular gap 7 between the separating elements 9 and the seals 8. When the sections of the spring 10 are compressed, the rod 3 is extended. Submersible equipment (submersible motor 19 , inlet filter 18 , pump 17 , see Fig. 3) connected to the inventive extension moves along the production string 16 down to the bottom of the well. When extending the rod 3 , the extension of the electrical line 14 (see Fig. 1) is ensured by its placement along the outer surface of the housing 1 in the form of a spiral. In this way, the integrity of the electrical line 14 is maintained when the hollow rod 3 is extended. In this case, placing the electrical line 14 outside the housing 1 eliminates the need to seal the inlet and outlet openings for the cable line 14 in the housing 1 .

The magnitude of the translational movement of the rod 3 and the piston 4 , connected to the rod 3 by means of screws 5 , is limited by limiting screws 12 installed in the guide grooves 11 . Limit screws 12 and guide grooves 11 provide protection against rotation of the rod 3 in the body 1 of the inventive extension.

Opening the flow line valve at the wellhead (not shown in the figures) causes a decrease in pressure inside the housing 1 of the inventive device to a certain operating value. The formation fluid is injected through the rod channel 3 , hole 6 in the piston 4 , adapter 2 along the tubing string 13 to the wellhead. When the pressure inside housing 1 decreases, the spring sections 10 expand and the rod 3 is pulled into the housing 1 . The submersible equipment arrangement, connected to the inventive extension, carries out a return movement towards the wellhead. In this case, the spiral of the cable line 14 is compressed into a spiral and is held along the body 1 by means of fasteners (clamps) 15 .

The separation of the internal cavity of the inventive extension and the internal channel of the production string 16 is carried out by means of seals 8 .

Thus, the proposed device provides elongation of the tubing string and controlled reciprocating movement of submersible equipment inside the well during oil production using submersible pump installations.

Claims (1)

A tubing string extension containing a housing, inside of which a hollow movable rod, a spring and separating elements are coaxially located, an adapter is installed for connection to the tubing string, and an electrical line in the form of a spiral is laid along the housing, characterized in that A piston is attached to the hollow movable rod, inside of which there is a coaxially located through hole for supplying liquid pumped by the pump; on the outer side of the piston there are at least two guide grooves for limit screws screwed in from the outside of the housing, while in the annular gap between the movable rod and seals are placed in the housing to separate the internal cavity of the device and the annulus, separating elements are installed between the spring and the seals in the specified annular gap, and the electrical line is laid outside along the extension body, while the tubing string extension is configured to be connected to the tubing string pipes in the upper part using an adapter, and in the lower part the tubing string is connected to a hollow movable rod.