RU2769022C1 - Wellhead self-centering wiper - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention relates to the oil industry, in particular to devices for shutting off the wellhead during lowering and retrieval of a pipe string in order to prevent foreign objects from falling into the well, as well as to clean the pipes from the well fluid lifted from the well. The wellhead self-centering wiper contains a body with a central hole and a slot that mates with the central hole. The body is equipped with holes for attaching the wiper to the wellhead. A wiping element is installed inside the case, made in the form of an elastic cuff, fixed between the upper and lower metal rings with the help of pins. The elastic cuff is equipped with a central hole and radial cuts. The housing is equipped with an internal cylindrical recess from below, in which a wiping element is installed with the possibility of rotation relative to the housing, as well as with the possibility of limited axial and radial movement relative to the housing. The elastic cuff of the wiping element, equipped with a central hole, is made of two stages: on top with a smaller diameter - d1 under the body of the pipe string, and on the bottom with a larger diameter - d₂ under the pipe coupling. The upper step of the two-stage elastic cuff with a diameter of – d₁ is equipped with radial cuts. The upper step with a diameter - d₁ of a two-stage elastic cuff has a greater thickness - h₁than the thickness h₂ of the lower step with a diameter - d₂. Two rows of threaded holes for studs are made in the body from above and below at an angle of 180° with respect to each other and with an offset of 45° for fastening the wiper from above to the spider, and from below to the wellhead flange. The inner diameters - D_r of the upper and lower metal rings are greater than or equal to the inner bore diameter - D_w of the production string of the well.

EFFECT: simplifying the design, improving the reliability of the device and the quality of cleaning the surface of pipes and couplings of tubing joints (TJ) or BT pipes pulled from the well, as well as eliminating time losses when passing pipe couplings through the device.

1 cl, 2 dwg

Description

The invention relates to the oil industry, in particular to devices for improving labor safety and environmental protection during well repair. The device is designed to shut off the wellhead during the tripping of a pipe string in order to prevent foreign objects from falling into the well, as well as to clean the pipes from the well fluid lifted from the well.

Known obtirator production LLC "UralPromSnabKomplekt" includes a body consisting of two wide metal rings with internal chamfers, between which two layers of replaceable elastic cuffs are fixed. Metal rings have internal stops, thanks to which the replaceable cuffs are not squeezed out under the weight of the column at the moment it is held by the spider. On the outer diameter, the rubber cuffs follow the contour of the body, and on the inner diameter of the tubing with a small allowance. The inner hole of the elastic cuff is notched in five places in the radial direction to form "petals", which are bent at the moment of cleaning the coupling or technological lock.

Device disadvantages:

- low reliability of work due to premature wear of the elastic cuff of the wiping element. Premature wear of the elastic sleeve is caused by one-sided wear of the sleeve due to the lack of the possibility of self-centering of the elastic sleeve relative to the tubing string during radial vibrations that occur during the lifting of the tubing string from the well;

- low quality of surface cleaning both on the body and on the sleeve of the tubing string or drill pipes (DT) due to the imperfect design of the elastic cuff, which, as a result of one-sided wear, does not clean the surface of the pipe body well. In addition, when passing through the elastic cuff of the pipe coupling, the “petals” notched in five places are bent upwards and do not completely cover the surface of the coupling, especially at the point of incision of the “petals” of the cuff;

- the duration of the extraction of the pipe string from the well. This is due to the presence of chamfers on the metal rings that come into contact with the pipe couplings and create additional resistance, therefore, when the pipe couplings pass through the device, it is necessary to slow down the lifting speed of the tubing or BT string, which delays the extraction of the pipe string from the well.

The closest in technical essence is a device for cleaning sucker rods (patent RU No. 2052072, publ. 01/10/1996), including a housing with a central hole and with means for fixing it to the wellhead, consisting of two parts with a node for fixing them relative to each other, and a wiping element located in the cavity of the body, in the form of elastic cuffs with a central hole, moreover, the elastic cuffs are fixed between the upper and lower metal rings with the help of pins, while the upper part of the body is made with a slot that mates with the central hole, and the fixation unit of the body parts is made in the form of studs and a stop on one part of the body and a shaped slot for studs and latches to interact with the stop on another part of the body, moreover, the elastic cuffs are made with radial cuts with gaps shifted by 45° in adjacent diaphragms.

Device disadvantages:

- the complexity of the design, due to the large number of components and parts;

- low reliability of work due to premature uneven wear of the elastic cuff of the wiping element. Premature uneven wear of the elastic sleeve is caused by one-sided wear of the sleeve due to the lack of the possibility of self-centering of the elastic sleeve relative to the tubing string or drill pipes (DT) during radial vibrations that occur during the lifting of the tubing string from the well;

- low quality of surface cleaning both along the body and along the sleeve of the tubing string (BT) due to the imperfect design of the elastic cuff, which, as a result of one-sided wear, does not clean the surface of the pipe body well. In addition, when passing through the elastic cuff of the pipe coupling, the “petals” notched in five places are bent upwards and do not completely cover the surface of the coupling, especially at the point of incision of the “petals” of the cuff;

- the duration of the extraction of the pipe string from the well. This is due to the presence of chamfers on the metal rings that come into contact with the pipe couplings and create resistance when lifting the pipe string from the well, therefore, when the pipe couplings pass through the device, it is necessary to slow down the speed of lifting the tubing string or BT string, which delays the time of retrieval of the pipe string from the well.

The technical objectives of the invention are to simplify the design, increase the reliability of the device and the quality of cleaning the surface of the couplings of the tubing string or BT pipe string, raised from their wells, as well as the elimination of time losses when the pipe string couplings pass through the device.

Technical problems are solved by a wellhead self-centering wiper containing a body with a central hole and a slot mating with the central hole, the body is also equipped with holes for attaching the wiper to the wellhead, and inside the body there is a wiper element made in the form of an elastic cuff fixed between the upper and lower metal rings with pins, the elastic cuff is equipped with a central hole and radial cuts.

What is new is that the body is equipped with an internal cylindrical recess from below, in which a wiping element is installed with the possibility of rotation relative to the body, as well as with the possibility of limited axial and radial movement relative to the body, the elastic cuff of the wiping element, equipped with a central hole, is made two-stage: on top with a smaller diameter - d ₁ under the body of the pipe string, and from below with a large diameter - d ₂ under the pipe coupling, and the upper step of the two-stage elastic cuff with a diameter of - d ₁ is equipped with radial cuts, while the upper step with a diameter of - d _{1 of} the two-stage elastic cuff has a large thickness - h ₁ than the thickness h _{2 of} the lower step with a diameter of - d ₂ , and in the body at the top and bottom at an angle of 180 ° relative to each other and with an offset of 45 ° there are two rows of threaded holes for the studs for fastening the wiper from above to the spider, and from below to the mouth well flange, while the inner diameters are D _{to the} upper and lower its metal rings are greater than or equal to the inner bore diameter - D _from the production string of the well.

In FIG. 1 schematically shows a wellhead self-centering wiper in a longitudinal section.

In FIG. 2 shows view A of a wellhead self-centering wiper.

Wellhead self-centering wiper contains a housing 1 (see Fig. 1 and 2) with a central hole 2 and a slot 3 (see Fig. 2), mating with the Central hole 2. Inside the housing 1 is installed wiping element 4 (see Fig. 1 ), made in the form of an elastic cuff 5 (see Fig. 1 and 2), fixed between the upper 6 (see Fig. 1) and lower 7 metal rings using pins 8.

The housing 1 is equipped with an internal cylindrical recess 9 from below, in which a wiping element 4 is installed with the possibility of rotation relative to the housing 1, as well as with the possibility of limited axial and radial movement relative to the housing 1.

Elastic cuff 5 wiping element 4, equipped with a Central hole 10 (see Fig. 1 and 2), made two-stage. The elastic cuff 5 is made from above with a smaller inner diameter d ₁ under the body 11 (see Fig. 1) of the outer surface of the pipe 12 (see Figs. 1 and 2), and from below with a larger inner diameter - d ₂ under the coupling 13 (see Fig. 1) pipes 12. The upper stage of the two-stage elastic cuff is equipped with radial cuts 14 (see Fig. 2) in the form of "petals".

As a pipe string 12, a tubing or BT string is used. For example, a tubing string with a diameter of 73 mm is used according to GOST 633-80. According to GOST 633-80, a tubing string with a diameter of 73 mm has a diameter of 73 mm along the pipe body, and a diameter of 88.9 mm along the pipe collar. Then for a two-stage elastic cuff 5 with an allowance, for example: 1-2 mm for rubbing the surface of the pipe string, we will take: d ₁ = 72.0 mm; d ₂ = 87.5 mm.

The elastic cuff 5 is made of rubber grades with increased strength and resistance to oil and oil products, which ensures their durability and reliability in operation, for example, GOST 7338-90 “Rubber and rubber-fabric plates. Specifications". The upper step with an inner diameter d _{1 of} a two-stage elastic cuff has a smaller thickness - h ₁ , for example 25 mm, than the thickness h _{2 of} the lower step with an inner diameter - d ₂ , for example 15 mm (h ₁ > h ₂ ).

Two rows of threaded holes 15 (see Fig. 2) and 16 (see Fig. 1 and 2) are made in the body at the top and bottom at an angle of 180° with respect to each other and with an offset of 45° for studs for attaching the wiper to the spider (not shown in Figs. 1 and 2) and to the wellhead flange 17 (see Fig. 1) of the production string 18 of the well.

The inner diameters - D _{to the} upper 6 and lower 7 metal rings are greater than or equal to the inner bore diameter - D _e of the production string 18 of the well. For example, D _e \u003d 130 mm, then we take D _to \u003d 130 mm (D _e \u003d D _to ).

The diameter of the central hole 2 of the body 1 is equal to the diameter D _{to the} top 6 and bottom 7 of the metal rings, i.e. 130 mm.

The device works as follows.

The body 1 is fixed to the base of the "spider" with the help of a number of threaded holes 15 (see Fig. 2) using two bolts (not shown in Figs. 1 and 2). Next, a wiping element 4 is installed on the wellhead flange 17 of the production string 18 of the well. Then the body 1, fixed to the "spider", is installed over the wellhead flange 17 and the wiping element 4 so that the wiping element 4 enters the inner cylindrical recess 9 of the body 1. Two bolts 19 are screwed into a row of threaded holes 16 of the body 1. Thus, the wellhead self-centering wiper at the wellhead between the "spider" and the wellhead flange 17 of the production string 18 of the well.

Simplifies the design of the device, which has easy-to-manufacture parts.

Next, start lifting the pipe string 12 from the well.

During operation of the device, when the pipe string passes through the elastic cuff 5, due to the possibility of rotation of the wiping element 4 around its axis and the possibility of its limited axial movement by the value - a and radial movement within the inner cylindrical sample 9 of the body 1 by the value - b, the wiping element is self-centering element 4 relative to the central axis of the pipe string 12.

For example, the displacement of the wiping element 4 relative to the housing 1 within the inner cylindrical sample 9 is:

- in the axial direction: a = 10 mm;

- in the radial direction (from one side to the other): 2 b, i.e. at b = 15mm: 2 15 mm = 30 mm.

As a result of self-centering of the wiping element 4 relative to the central axis of the pipe string 12, the elastic cuff is completely covered both along the body 11 and along the sleeve 13 of the pipe string 12. to prolong the service life of the elastic cuff 5 of the wiping element 4, and consequently improve the reliability of the device.

In the process of lifting the pipe string 12 from the well, the outer part of the body 11 and the sleeve 13 of the pipe string 12 are wiped off using a two-stage cuff 5.

When the body 11 of the pipe 12 passes through the device, the upper stage with a diameter d _{1 of} the two-stage elastic cuff 5 works, while in the process of lifting the string of pipes 12 from the well, the wiping element 4 itself, as described above, is displaced in the axial and radial direction, and also rotates, which ensures dense coverage over the entire area of the body 11 of the pipe 12 by the upper step with a diameter d _{1 of} the two-stage elastic cuff 5. As a result, the body 11 of the pipe 12 is cleaned qualitatively.

When the coupling 13 of the pipe 12 reaches the device, the lower step with a diameter d _{2 of} the two-stage elastic cuff 5 comes into operation, while the upper step with a diameter d _{1 of} the two-stage elastic cuff 5 due to the radial cuts 14 in the form of "petals" bends upward and does not interfere with the passage of the coupling 13 of the pipe 12 through the device.

The absence of cuts 14 in the form of "petals" in the design of the lower stage of the two-stage elastic cuff 5 allows the lower stage with a diameter d ₂ to tightly cover the coupling 13 of the pipe 12 over the entire contact area, which undoubtedly improves the quality of cleaning the surface of the coupling 13 of the pipe 12 when it passes through the device.

After the passage of the sleeve 13 of the pipe 12 through the device, the first step with a diameter d _{1 of} a two-stage elastic cuff 5, made with radial cuts 14 in the form of "petals" returns down and takes the position shown in figure 1.

Then, as described above, the upper step with a diameter d _{1 of} the two-stage elastic cuff 5 again enters into operation, and the operation of the device is repeated.

The cleaning area of the surface of the body 11 of the pipe 12 is a multiple of the cleaning area of the surface of the coupling 13 of the pipe 2, therefore the upper stage with an inner diameter d _{1 of} a two-stage elastic cuff has a greater thickness - h ₁ than the thickness h _{2 of} the lower stage with an inner diameter - d ₂ , (h ₁ > _h2 ). This evens out the wear of the two-stage cuff on both stages and extends the life of the two-stage elastic cuff.

Thus, the improved design of the elastic sleeve makes it possible to improve the quality of cleaning the surface of the tubing or BT pipe string both along the body and along the pipe sleeve.

Structurally, the inner diameters - D _{to the} top 6 and bottom 7 metal rings are greater than or equal to the internal bore diameter - D _e of the production string (D _e \u003d D _to ), and the diameter of the central hole 2 of the body 1 is equal to the diameter D _{to the} top 6 and bottom 7 metal rings , as described above 130 mm. Due to this, the inner diameter of the device is greater than or equal to the inner diameter of the production string, which eliminates both the need to make internal chamfers on the metal rings and eliminates the contact of the metal rings of the device with the pipe couplings, which in turn eliminates resistance to the rise of the pipe string and does not slow down the speed of the string tubing or BT from the well. As a result, the loss of time for cleaning the surface of the pipe string when it is pulled out of the well is reduced.

Simplifies the design of the device, which has easy-to-manufacture parts.

The device allows:

- simplify the design of the device;

- increase the reliability of work;

- improve the quality of cleaning the surface of the body and couplings of the pipe string;

- reduce the loss of time for cleaning the surface of the pipe string when lifting it from the well.

Claims (1)

A wellhead self-centering wiper, containing a body with a central hole and a slot mating with the central hole, the body is also equipped with holes for attaching the wiper to the wellhead, and inside the body there is a wiper element made in the form of an elastic cuff fixed between the upper and lower metal rings with using pins, the elastic cuff is equipped with a central hole and radial cuts, characterized in that the body is equipped with an internal cylindrical recess from below, in which a wiping element is installed with the possibility of rotation relative to the body, as well as with the possibility of limited axial and radial movement relative to the body, the elastic cuff of the wiping element , equipped with a central hole, is made two-stage: from above with a smaller diameter - d ₁ under the body of the pipe string, and from below with a large diameter - d ₂ under the pipe coupling, and the upper stage of the two-stage elastic cuff with a diameter - d ₁ is equipped and by radial cuts, while the upper step with a diameter of - d _{1 of} a two-stage elastic cuff has a greater thickness - h ₁ than the thickness h _{2 of} the lower step with a diameter of - d ₂ , moreover, in the case above and below at an angle of 180 ° with respect to each other and with 45° offset made two rows of threaded holes for studs for fastening the wiper from above to the spider, and from below to the wellhead flange, while the inner diameters - D _{to the} upper and lower metal rings are greater than or equal to the inner diameter - D _from the production string of the well.

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