RU21930U1 - WELL MOUNT SEALING DEVICE - Google Patents

Description

Device for sealing the wellhead.

The utility model relates to the mining industry, and more particularly to blowout preventer devices of a boom long pipe (BDT) and can be used to seal the wellhead during repair in coiled tubing technology.

A known sealant of a movable pipe string comprising a housing, an outer seal and an inner seal associated with the housing, consisting of an elastic sleeve reinforced with metal rings, a working seal and two covers (Aut. St. USSR No. 825855, M. C. E21B 33/06, stated 23.03.79, publ. 30.04.84).

In the known device, the presence of an additional internal seal complicates the design of the device and reduces its reliability.

A wellhead sealant is also known, which is used during tripping operations with a pipe string in pressurized wells (ed. St. USSR No. 1645456, M. Cl. E21B 33/03, decl. 06.12.88, publ. 30.04. 91). The sealant contains a cylindrical body with flanges and with radial and central axial channels for placement in the last pipe string. A sealing assembly in the form of an elastic annular cuff is installed in the housing, which forms an annular cavity connected with the source of overpressure with the housing. The elastic sealing element is made in the form of a torus and is mounted for rotation and axial movement relative to the housing in the annular grooves of the elastic annular cuff, and the grooves are made on the inner surface of the cuff. Concentric in the housing above and below the sealing assembly are guide rings.

The disadvantage of the sealant is also the complex design of the sealing element. In addition, in the known sealant, the overpressure cavity is directly connected to the elastic sealing element, i.e. the pressure is applied directly to the gasket and when entering the pipe 2001 jj - y-yni J4

M.C. Е21В 33/03 would be possible to break into the well. Also, the issue of replacing elastic

sealing element during the process.

The closest technical solution to the claimed is a device for sealing the wellhead, comprising a housing with a radial channel for communication with a pressure source (Aut. St. No. 1557313, M. Cl. E21B 33/03, decl. 06.12.88, publ. 30.04. 91). In the upper part of the casing, a connecting flange with annular protrusions is rigidly installed, one of which is designed to stop the casing in it. Inside the housing there is a hollow differential piston with a conical inner surface to which the guides are rigidly attached. Wedges with interchangeable dies are movably mounted on the guides. A figured sealing element is located in the housing, under which there is a reinforcing ring with radial grooves on the outer surface to accommodate the protrusions of the wedges. The piston and the annular protrusion of the connecting flange installed in the housing form a piston cavity, and the piston and housing form a piston annular cavity. Both cavities are connected through radial channels to a pressure source. During operation of the device, a pressure is applied to the sub-piston cavity, which acts on the piston and moves it up. At the same time, the protrusions of the wedges interact with the radial grooves of the ring and press it together with the locking element upwards, thereby sealing the space between the outer surface of the casing and the inner surface of the connecting flange.

The known device increases the safety of the work performed in an open fountain. However, the disadvantage of this device is the presence of guides attached to the piston, which has a conical surface, wedges with protrusions and rings with radial grooves. All this complicates the design of the device and, therefore, reduces its reliability. The device also does not provide for the replacement of the sealing element during the process without killing the well.

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replacement of sealing elements during repair work in coiled tubing technology with sleeveless long pipes (BDT) without killing the well.

The problem is achieved in that in a device for sealing a wellhead containing a cylindrical body rigidly connected to a hydraulic cylinder in which a full piston is placed, radial channels for communication with a pressure source, a sealing element with guide rings located above and below the sealing element installed in the housing and the support sleeve, the emphasis is installed in the upper part of the housing, and the emphasis, guide rings and sealing element are made detachable. The connector surface of the retention element is made in the form of an ellipse. The guide rings in the connector have an oblique cut.

The execution in the upper part of the body of the detachable stop made of 2 halves and located on the upper guide split ring allows you to change the sealing element with the lowered drill bit without killing the well, and the implementation of the stop, sealing element and guide rings detachable makes it easy to replace the sealing element during the process without killing the well. The design of the sealing element, made of elastic material, and having on the surface of the connector along the entire height of the figured protrusions and depressions mating with each other, as well as forming surfaces in the form of an ellipse, eliminates leakage of well products and reliably seals the wellhead. The presence of a bevel in the guide rings in place of the connector during operation under pressure also prevents the passage of well products and protects the sealing element.

A specific embodiment of the device is illustrated by drawings, where in FIG. 1 shows a device for sealing a wellhead, general view;

figure 2 is a section aa of figure 1; in Fig.Z - section BB section AA; figure 4 - sealing element, General view;

figure 5 - section bb In figure 4; in FIG. 6 is a section G-D of FIG. 4.

The device for sealing the wellhead comprises a cylindrical body 1, in the upper part of which a stop 2 is made, made of 2 halves and fixed with pins 3. Inside the body 1, a detachable sealing element 4 is made of elastic material. Above and below the sealing element, detachable guide rings 5 are installed, which serve to center the pipe (BDT) 6 of the relative sealing element 4 and having an oblique cut in the connector 7. The lower guide ring 5 is mounted on the supporting sleeve 8, which rests on the end face of the hollow piston 9 of the hydraulic cylinder 10 rigidly connected with the housing 1. The hydraulic cylinder 10 has a cover 11 from the bottom 11. The hydraulic cylinder 10 is connected through a radial channel 12 to a pressure source (not shown in the drawing) and forms a piston cavity 13 with the hollow piston 9. ying the radial passage 14 is also connected to a pressure source (not shown) above the piston and the cavity 15 formed by the hollow piston 9 and the housing 1. By means of the nut 16, the sealing ring 17 and cover unit 11 is fixed to the preventer. The surfaces of the connector 18 (Fig. 6) of the sealing element 4 are made with an inclination angle of "5 ° and have alternating curly protrusions 19 and depressions 20 mating to each other over the entire height (Fig. 5). The forming surfaces of the sealing element 21 to 22 are elliptical (Fig. 6).

The device operates as follows. Before starting work on the well using coiled tubing technology, the device for sealing the wellhead is mounted on the preventer using a nut 16 and an o-ring 17. A pipe (BDT) 6 is inserted into the device until the end of the device exits when the preventive well is shut off by the preventer. Through the radial channel 12, a pressure is applied to the piston cavity 13, which acts on the hollow piston 9 and moves it upward. In this case, the hollow piston 9, through the support sleeve 8, compresses the sealing element 4 between the guide rings 5, the stop 2, the housing 1 and the outer surface of the pipe (BDT) 6, and under

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presses it tightly against the pipe (BDT) 6. In this case, on the surfaces of the connector 18, alternating protrusions 19 and depressions 20 are interconnected and sealed, eliminating the leakage of well products through the connector of the sealing element 4. The radial channel 12 of the subsurface cavity 13 is closed by a locking device and controlled by a pressure sensor (not shown). The descent of the pipe 6 into the well and the necessary technological treatment of the well.

Downhole pressure, if any, acts on the ends of the support sleeve 8 and the hollow piston 9, which compress the sealing element 4, and thereby contribute to the sealing of the pipe. When compressing the sealing element 4, the surfaces of the connector 18, made with alternating depressions 20 and protrusions 19, mating with each other, are additionally compressed and sealed, thereby eliminating leakage of well products through the sealing element 4. Guide rings 5 made of non-ferrous metal guide the pipe 6 and clean it from adhering downhole products and particles, thereby contributing to a reduction in seal wear, and the oblique cut 7 of the guide ring connector 5 eliminates leakage of downhole products, because compacted under pressure.

If it is necessary to replace the sealing element in the process of carrying out a technological operation with a wound pipe (BDT) 6, lowering of the pipe 6 is stopped. Close the tube dies preventer and relieve hydraulic pressure in the piston cavity 13. The piston is in the lower position. Pins 3 of detachable stop 2 are removed. Pressure is applied to the sub-piston cavity 13 through the radial channel 12. In this case, the hollow piston 9 moves up to the end of the stroke and pushes the split stop 2, the guide rings 5 and the sealing element 4. The stop 2, the sealing element 4 and the guide rings 5 are removed. The pressure from the sub-piston cavity 13 is removed and transmitted through the radial channel 14 to the supra-piston cavity 15. The hollow piston 9 is lowered and the sealing element 4 is replaced. The detachable stop 2, the new sealing element 4 and the guide rings 5 are installed in the working position of the housing 1 and fixed with pins 3 The pressure is applied to the cavity 13 through the radial channel 12, having removed it in the supra-piston cavity 15 and the technological process continues.

Claims (2)

1. A device for sealing the wellhead, comprising a cylindrical body rigidly connected to the hydraulic cylinder, a hollow piston located in the hydraulic cylinder, radial channels for communication with a pressure source, a sealing element installed in the housing, guide rings located above and below the sealing element and a support sleeve, characterized in that it contains an emphasis mounted in the upper part of the housing, the emphasis, the sealing element and the guide rings are made detachable, and the sealing element has connector surfaces with alternating protrusions and depressions mating with each other and forming surfaces in the form of an ellipse. 2. The device according to claim 1, characterized in that the guide rings in the place of the connector have an oblique cut.