RU2283941C1 - Troublesome well zone isolation device - Google Patents

Abstract

FIELD: oil and gas industry, particularly well cementing means, for instance secondary well cementing under pressure for well repair, for separation bridge installation in well in predetermined intervals and for other well isolation works performing.

SUBSTANCE: device comprises hollow shaft with hydraulic cylinder fastened in upper device part, radial orifices in lower part thereof and shoe located under the orifices. Sealing unit with support members and cones located on outer shaft surface is also provided. Device comprises lower jaw for device fastening on well wall, hydraulic drive to bring lower jaw in working position, which is combined with isolation solution supply unit adapted to inject isolation solution in well. The unit is made as lower and upper seats arranged inside shoe or shaft below radial orifices. The seat is adapted for free fall elastic member receiving and is located in annular gap between the shoe and outer surface of annular piston shaft. Working space of the piston is connected to shaft interior through radial orifices. Sealing unit deformation assembly is connected with mechanical drive, which brings upper jaw in working position to provide additional device fastening to well wall. The mechanical drive is made as installation unit having clutch in upper unit part. One clutch end is adapted to be connected to pipes for device lowering in well. Another clutch end is fixedly fastened to connection pipe and to nipple made as hollow piston. The nipple and hollow piston define annular gap for hydraulic cylinder installation. Connection pipe is installed outside of hydraulic cylinder and is connected with it by shear members to provide deformation force transmission from pipes to sealing unit for device lowering in well in working device position. Nipple-piston is located in hydraulic cylinder and has length, which differs from connection pipe length for not more than 20%.

EFFECT: increased operational reliability and simplified device structure.

6 cl, 1 dwg

Description

The present invention relates to the field of the oil and gas industry and, in particular, to the field of isolation work in wells, for example, secondary (correctional, repair) cementing of wells under pressure. The invention can also be used when installing disconnecting bridges in the well at the required intervals, as well as in any other isolation operations in the well. The device takes into account the specificity of technology inherent in cementing work.

A device for isolating a well is known, including a docking unit for connecting to a pipe string, a nozzle connected to the docking unit by a detachable connection and made in its lower part with a landing seat for a thrown element, dies and wedges placed on the nozzle and interacting with each other, and a sealing element placed on the pipe with the possibility of its deformation from axial force through the docking unit (see, for example, Krylov V.I. et al., Complications when drilling wells, M., Nedra, 1965, pp. 186-187).

A disadvantage of the known device is its limited use in wells due to, for example, insufficient reliability of work in wells, especially deviated wells, significant labor costs when restoring a well section after performing isolation operations. In addition, the known device does not provide the necessary pressure drops in the well during the insulation process and after their implementation with a rather complex design.

The technical result of the invention is to increase the reliability of the device and simplify its design.

The required technical result is achieved in that the device for isolating the complication zone in the well includes a hollow barrel with a hydraulic cylinder in the upper part, radial holes in the lower part and a shoe under these holes, a sealing assembly with supporting elements and cones placed on the outer surface of the barrel, the lower die for fixing the device to the wall of the well, the hydraulic drive of the lower plate to the working position, combined with the node supplying the insulating solution to the well in the form of an upper and lower return landing seat inside the shoe or barrel, below the radial holes, under the thrown elastic element and placed in the annular space between the shoe and the outer surface of the barrel of the annular piston, the working space of which is connected with the barrel cavity through the radial holes, the deformation unit of the sealing assembly, combined with a mechanical drive the upper die in its working position for additional fixation of the device to the wall of the well and made in the form of a mounting unit with a coupling in the upper part, one to the end of which is used to connect with the pipes to lower the device into the well, and the other is rigidly connected to the pipe and nipple in the form of a hollow plunger, forming an annular cavity between them, in which the hydraulic cylinder is located, while the pipe is installed outside the hydraulic cylinder and connected with shear elements, and has the ability to transfer the deformation force to the sealing assembly from the pipes to lower the device into the well in the working position of the device, and the nipple-plunger is placed in the hydraulic cylinder and has a length of not more than 20% different from ins pipe.

Besides:

the upper and lower dies are made with the possibility of their longitudinal connector in the working position of the device when interacting with the cones and have the ability to fix them on the wall of the well and lock;

the device has bushings at the ends of the sealing element, made with concave surfaces enveloping the sealing assembly;

when the position of the thrown elastic element on the lower return seat is made, the device is designed for the final pressure of the insulating mortar;

waste element made of rubber;

the nodes of the device are made of drillable material.

The drawing shows a General view of the device.

A device for isolating a complication zone in a well, in particular, is in particular a cementing device, a kind of cementing packer. It includes a hollow barrel 1 with a hydraulic cylinder 2 in the upper part, radial holes 3 in the lower part and a shoe 4 under these holes. The device also has a sealing assembly 5 with support elements with cones 6, 7, located on the outer surface of the hollow shaft 1, a lower die 8 for fixing the device to the wall of the well (not shown conditionally). The bottom plate 8 has a hydraulic drive, combined with the node supplying the insulating solution to the well in the form of an upper landing seat 9 and a lower return landing seat 10 inside the shoe 4 or hollow shaft 1, below the radial holes 3, under the thrown shut-off elastic element 11. Directly into the hydraulic the drive of the lower die 8 includes an annular piston 12, placed in the annular space between the shoe 4 and the outer surface of the barrel 1. The working space 13 of the annular piston 12 is connected with the cavity 14 of the barrel via openings 3. The device has a deformation assembly of the sealing assembly 5, which is combined with the mechanical drive of the upper ram 15 to its working position for additional fixation of the device to the borehole wall. The deformation unit of the sealing unit is made in the form of a mounting unit with a clutch 16 in the upper part of the device. One end of the sleeve 16 is used to connect with pipes for lowering the device into the well (not shown conditionally), and the other end of the sleeve is rigidly connected to the pipe 17 and the nipple 18, made in the form of a hollow plunger. The pipe 17 and the nipple-plunger 18 form between themselves an annular cavity 19, in which the hollow barrel 1 is located with its hydraulic cylinder 2. The pipe 17 is installed outside the hydraulic cylinder 2, connected with shear elements 20 and has the ability to transmit the deformation force to the sealing unit 5 from the pipes for lowering the device into the well in its working position. For this, the pipe may, for example, be equipped with a centralizer 21 in the lower part. Between this centralizer and the upper ram, a locking unit 22 with retaining elements 23. A locking element may be provided for the lower ram 8. The nipple-plunger 18 is placed in the hydraulic cylinder 2 and has a length of not more than 20% different from the length a nozzle for ensuring the rigidity of the device (reducing its axial deformation) when transmitting axial force to it and ensuring a predetermined (regulated) deformation mode of the sealing assembly. This ratio of the sizes of the nipple plunger 18 and the pipe 17 is obtained empirically for this device design.

In addition, the device shows:

elements 24 for sealing the nipple-plunger 18 in the hydraulic cylinder 2;

a sleeve 25 in which the upper 9 and lower reverse 10 landing seats are made;

shear elements 26 for fixing the lower support element 7 with a cone to the barrel;

locking elements 27 for the bottom die 8.

The device operates as follows.

Before the device is lowered into the well, it is connected to the installation unit in the following order. In the upper inner part of the barrel 1, its hydraulic cylinder 2, a nipple-plunger 18 is installed. The interaction surface of the nipple-plunger 18 with the hydraulic cylinder 2 is sealed with o-rings 24, which can be placed in the cylinder or nipple. The nipple 18 is connected to the clutch 16. With the same clutch the pipe 17 is also connected, which is installed outside the hydraulic cylinder 2.

The barrel 1 with the hydraulic cylinder 2 is rigidly fixed with shear elements 20 on the pipe 17.

Then the installation site through the coupling 16 is connected to the pipes for lowering the device into the well, for example, with a tubing string. The assembled arrangement is lowered into a predetermined interval of the well. Then bring the device into position. To do this, in the tubing string by pumping the working fluid create direct circulation through the open bore of the barrel 1 and shoe 4. After washing from the wellhead through the tubing string, the locking elastic element 11 is dropped, which sits in the upper landing seat 9 and seals the inner cavity 14 of the barrel 1. An installation pressure of about 10-15 MPa is created in the tubing string, which, through the radial holes 3 in the barrel 1, acts on the annular piston 12. The annular piston is displaced in the axial direction (up) and acts on the lower plate 8. When the lower die 8 interacts with the cone of the supporting element 7, its longitudinal connector — rupture — occurs (destruction in the stress concentration zones created, for example, along longitudinal grooves). The bottom plate 8 is embedded in the wall of the well, for example a casing, and fixes the device from axial movement down. Then the pressure inside the tubing string is vented, for example, in steps to hydrostatic pressure in the well. Next, the device is loaded with part of the weight of the tubing string. Carry out the landing device in the well, for example, in a casing string. The weight of the tubing string is initially perceived by the shear elements 20. When unloading the tubing string onto the device, for example, 3-5 tons, the shear elements 20 are cut off and the mounting unit moves down the device barrel, for example, acting through the centralizer 21 on the locking unit 22, displacing it and device elements between the upper 15 and lower 8 dies and supporting elements 6, 7. When moving the upper die 15 and the cone of the supporting element 6 down, the sealing elements of the sealing assembly 5 between its supporting elements with cones 6, 7 deform and fill the rings howling space between the barrel 1 and the borehole wall, such as the casing. Further movement of the upper ram 15 leads to its longitudinal connector (rupture) and displacement along the cone 6 to the wall of the well. In this case, the locking elements of this plate are embedded in the wall of the well and rigidly fix the device in a given interval of the well. The locking nodes of the upper and lower dies rigidly fix the sealing elements of the sealing unit 5, as well as the supporting elements with cones 6, 7 from moving along the barrel 1 of the device. The landing of the device is carried out when unloading the weight of the tubing string by 8-10 tons.

After the device is planted in the well, the pressure of the working fluid inside the tubing string is increased to a pressure of 15-18 MPa to press the locking elastic element 11 under the lower return seat 10 and to connect the cavity of the tubing string and cavity 14 of the barrel 1 with the well zone under the device that seals the annular space of the well at the installation location of this device. Determine the tightness of the landing device in the well by creating pressure in the area under the device. Then the pressure in the tubing string is relieved, for example, in steps, to the hydrostatic pressure in the well. By slowly lifting the tubing string, the installation unit is removed from the barrel 1 of the device. Replace the working fluid, if necessary, with an insulating solution. Next, the installation unit is again connected to the barrel 1. In this case, the landing force (unloading of the tubing string) on the device should be within, for example, 3-5 tons.

After planting the installation site, the pressure in the tubing string is increased, checking its tightness. The insulation solution is injected into the zone under the device installed in the well. After the completion of the injection of the insulating solution in the required volume and according to the specified technology, the pressure in the tubing string is relieved (bleed, for example, in steps). The locking elastic element 11 automatically closes the device with the landing of this element on the lower return seat 10 under pressure in the area under the installed device. The installation site is again removed from the device by slowly lifting the tubing string up. Flushing the well and subsequent lifting of the tubing string with the installation unit from the well are carried out.

Claims (6)

1. A device for isolating the complication zone in the well, including a hollow barrel with a hydraulic cylinder in the upper part, radial holes in the lower part and a shoe under these holes, a sealing assembly with supporting elements and cones placed on the outer surface of the barrel, a lower die for fixing the device to the wall of the well, the hydraulic drive of the lower die to the working position, combined with the node for supplying the insulating solution to the well in the form of an upper and lower reverse landing saddle inside the shoe or barrel, n the same radial holes, under the junk elastic element and placed in the annular space between the shoe and the outer surface of the barrel of the annular piston, the working space of which is connected with the cavity of the barrel through the radial holes, the deformation unit of the sealing assembly, combined with the mechanical drive of the upper die in its working position for additional fixing the device to the wall of the well and made in the form of a mounting unit with a sleeve in the upper part, one end of which serves to connect with pipes for sp ska device into the well, and the other is rigidly connected to the pipe and the nipple in the form of a hollow plunger, forming between themselves an annular cavity in which the hydraulic cylinder is placed, while the pipe is installed outside the hydraulic cylinder and connected with shear elements and has the ability to transmit deformation forces to the sealing unit from pipes for lowering the device into the well in the working position of the device, and the nipple-plunger is placed in the hydraulic cylinder and has a length of not more than 20% different from the length of the pipe. 2. The device for isolating the well according to claim 1, characterized in that the upper and lower dies are made with the possibility of their longitudinal connection in the working position of the device when interacting with the cones and have the possibility of their fixation on the wall of the well and locking. 3. The device for isolating the well according to claim 3, characterized in that it has bushings at the ends of the sealing element, made with concave surfaces enveloping the sealing assembly. 4. The device for isolating the well according to claim 1, characterized in that when the position of the thrown elastic element on the lower return landing seat, the device is designed for the final pressure of the selling insulating solution. 5. The device for isolating the well according to claim 1, characterized in that the waste element is made of rubber. 6. The device for isolating the well according to claim 1, characterized in that its nodes are made of drillable material.