RU2747903C1 - Device for sealing the mouth of inclined well during round-trip operations of double-row pipe string - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to a device for sealing the mouth of oil and gas wells with an inclined mouth and a two-row pipe string. The proposed device for sealing the running of a two-row pipe string into an inclined well contains a preventer (1) with lifting lugs (2 ', 2' ') and a cast bottom flange (3), and equipped with a replaceable ring (5). In this case, the replaceable ring is installed under the lower flange with the possibility of hermetically sealed fastening with a bolted connection (7). The bottom flange (3) of the BOP (1) is equipped with a metal ring (6), which is sealed to the support flange (8) of the wellhead assembly. The replaceable ring (5) is made with annular grooves with the possibility of installing sealing metal rings (9). The device is also equipped with a pipe hanger for the first row of the pipe string, and the lower flange of the pipe hanger is attached from below to the support flange of the wellhead. At the same time, threaded holes are diametrically made in the pipe holder from above with a connecting and sealing size corresponding to the connecting and sealing size of the bottom flange of the preventer. In addition, the device is equipped with centralizers (16', 16''), installed in the device before attaching the preventer to the support flange (8) of the wellhead assembly or pipe hanger. The inner diameters of the centralizers depend on the diameters of the double-row pipe string, which is lowered into the deviated well, and the lower and upper ends of the centralizers are equipped with chamfers. The inner surfaces of the metal O-rings are fitted with 5mm high temperature FRM O-rings. Additionally, the device is equipped with two slings of different lengths for mounting the preventer on the support flange of the wellhead and the pipe hanger. In this case, the difference between the length of the lines depends on the distance between the lifting lugs of the preventer. To seal the internal space of the first and / or second row of pipe strings, a shut-off element is used.

EFFECT: increases reliability and expanding technological capabilities of the device when carrying out sequential trips with two pipe strings in an inclined well with ability to adjust the angle of inclination of the preventer when installing it on the support flange of the wellhead in an inclined well.

1 cl, 4 dwg

Description

The invention relates to a device used in preventers designed to seal the wellhead of oil and gas wells with various types of supporting flanged wellheads in order to ensure safety, prevention and elimination of oil and gas wells, including superviscous oil wells (EHV) with inclined wellhead and double-row pipe string.

Known preventer for wells with inclined mouth (patent RU No. 2719884, publ. 04/23/2020), containing upper and lower flanges, rigidly connected to the body, the body is equipped with a vertical circular axial channel, relative to the axial channel are symmetrically located lateral horizontal channels, longitudinal axes of the lateral horizontal channels are located perpendicular to the axis of the vertical channel, in the first horizontal channels made in the body with the possibility of longitudinal movement, ram blocks are installed in which pipe rams are located, equipped with elastic seals, and manual drives for controlling rams, including drive rods of the rams, having threaded connections for interactions with covers screwed into the body, while the cavities of the body of the ram blocks in the cross section have a rectangular shape, and the elastic seals are placed in the grooves made in the pipe rams, the upper and lower parts of the axial channel of the body are equipped with conical seating surfaces yami, moreover, the upper conical surface is made tapering from top to bottom and an upper replaceable centering sleeve is installed in it, made in the form of two half rings, equipped with external annular recesses, and the lower conical surface is made tapering from bottom to top and a lower replaceable centralizer is installed in it, while in the upper the flange is made of the second horizontal channels of a circular shape in cross-section, from the outside into the horizontal channels of the upper flange in a sealed design, side screw stops are screwed in, interacting with the cylindrical sliding sliders located in the horizontal channel, while the sliding sliders are equipped with keyway and shaped grooves, and the upper flange equipped with keys installed in the keyways of the sliding sliders, which can move radially within the keyways and fix the sliders with the curly slots behind the outer annular recesses of the upper replaceable centering sleeve from its axial movement upwards, while The slopes of the tapered seating surfaces provide the distance between the lower end of the upper replaceable centering sleeve and the upper end of the lower replaceable centralizer, shorter length of the coupling of the pipe string to be sealed with a minimum diameter, and the elastic seals of the preventer are made of heat-resistant rubber, and the upper replaceable centering sleeve and the lower replaceable centralizer are made from babbitt alloy.

Disadvantages of the device:

- firstly, the complexity and long duration of equipment assembly and mounting (dismantling) of the preventer on the wellhead support flange, associated with the need to use a coil for piping the preventer with different standard sizes of wellhead support flanges;

- secondly, the duration and inconvenience of installing the preventer on the supporting flange of a well with an inclined wellhead, since it is necessary to manually tilt the preventer to the required angle to join its lower flange with the supporting flange of the wellhead, since the lifting clamps are made at the same level from the lower flange of the preventer ;

- thirdly, the low safety of work at the head of inclined wells of the EHV, as well as in a critical situation in the event of an OGVP, associated with the need to tilt the preventer to the desired angle, followed by hermetic joining of the lower flange with the support flange of the wellhead in emergency mode.

The closest in technical essence and the achieved result is a preventer with a replaceable ring (patent RU No. 2724695, publ. 06/25/2020), containing a preventer with a cast bottom flange, hermetically attached to the support flange of the wellhead, the bottom flange of the preventer is made with a connecting and sealing size, corresponding to the minimum dimensions of the wellhead support flange, while the preventer is equipped with a replaceable ring made of connecting and sealing dimensions corresponding to the dimensions of the wellhead support flange on which the preventer is attached, and the replaceable ring is installed under the bottom flange with the possibility of hermetic fastening by bolting, the lower flange of the preventer equipped with a metal ring, and the connecting size of the lower flange corresponds to the center-to-center diameter of the bolted connection made in the replaceable ring, lifting lugs are rigidly fixed to the preventer body with a height offset relative but apart from each other with the possibility of installing a preventer at the mouth of an inclined well, the replaceable ring is made with annular grooves with the possibility of installing sealing metal rings.

Disadvantages of the device:

- firstly, the low reliability of the device in steam injection wells with a double-row pipe string, associated with the loss of the preventer tightness at the place where the preventer is attached to the wellhead assembly of an inclined well through metal sealing rings. This is due to the fact that the string of pipes, lowered into the well through the preventer, "lies on one side" in the preventer, and when OGVP occurs in the form of a steam release injected into the steam injection well at a temperature of 200-250 ° C, leaks are formed through the metal sealing ring;

- secondly, the device does not have the ability to adjust the angle of inclination of the preventer when installed on the support flange of the wellhead, depending on the angle of inclination of the inclined well, since the lifting lugs are fixed in the preventer with an offset in height relative to each other with the possibility of installing the preventer at the wellhead deviated wells strictly at a certain angle, for example 45 °;

- thirdly, the duration of work during round-trip operations (ROP) with a pipe string in an inclined well. This is due to the fact that, due to the lack of centering of the pipe string relative to the axis of the inclined well, when lowering the coupling, the pipe string clings to the upper end of the upper flange of the preventer, and when lifting, they cling to the lower end of the lower flange of the preventer, which leads to the need for additional manipulations with the column. pipes for the purpose of passing the pipe string through the preventer. This delays the STR process;

- fourthly, the limited technological capabilities of the device when conducting a sequential trip with two pipe strings in an inclined well, since the device allows running only one pipe string into a well with any standard size of the wellhead support flange, but does not allow sequential running into one well two pipe strings with any standard size of the wellhead support flange.

The technical objectives of the invention are to improve the reliability of the device in a steam injection well with a double-row pipe string with the ability to adjust the angle of inclination of the device when it is installed on the support flange of the wellhead depending on the inclination angle of an inclined well, to reduce the duration of work when carrying out trials with a pipe string in an inclined well and expanding the technological capabilities of the device when conducting successive trips with two pipe strings in an inclined well.

Technical problems are solved by a device for sealing the wellhead of an inclined well during tripping and lifting operations of a double-row pipe string, containing a preventer with lifting lugs and a cast bottom flange, made with a connecting and sealing size corresponding to the minimum dimensions of an attachment at the wellhead of an inclined well, the device is equipped with a replaceable ring, from above, a replaceable ring is installed under the bottom flange of the blowout preventer with the possibility of hermetic fastening with it using a sealing metal ring and a bolted connection, the connecting size of the lower flange corresponds to the center-to-center diameter of the bolted connection made from the top in the replaceable ring, from the bottom the replaceable ring is installed on the supporting flange of the wellhead assembly with the possibility of hermetic fastening by means of a sealing metal ring with a bolted connection, the connecting size of the supporting flange of the directional wellhead equipment is acc. It corresponds to the center-to-center diameter of the bolted connection made from below in the replaceable ring.

The novelty is that the device is equipped with a pipe hanger of the first row of pipe string, and the lower flange of the pipe hanger is attached from the bottom to the support flange of the wellhead, while on top of the pipe hanger there are diametrically made threaded holes with a connecting and sealing size corresponding to the connecting and sealing size of the lower flange of the preventer, the device equipped with centralizers installed in the device before attaching the preventer to the support flange of the wellhead or pipe hanger, while the inner diameters of the centralizers depend on the diameters of the double-row pipe string, lowered into the deviated well, with the lower and upper ends of the centralizers equipped with chamfers, and on the inner surfaces of the metal sealing rings high-temperature O-rings made of fluorocarbon rubber FRM with a thickness of 5 mm are installed, and the device is equipped with two slings of different lengths for installing the preventer on the support flange of the wellhead equipment and pipe holder l, in this case, the difference between the length of the lines depends on the distance between the lifting lugs of the preventer, while a shut-off element is used to seal the internal space of the first and / or second row of pipe strings.

FIG. 1 and 2 schematically and sequentially depict the proposed device for sealing the mouth of an inclined well during tripping and lifting operations of a two-row pipe string.

FIG. 3 shows an enlarged view A of the structure of the metal sealing ring 6.

FIG. 4 shows an enlarged view B of the sealing metal ring 9.

The device contains a preventer 1 (Fig. 1, 2) with four lifting lugs 2 '; 2 "; and a cast bottom flange 3 (Figs. 1, 2, 3), made with a connecting and sealing size corresponding to the minimum dimensions of an attachment at the mouth of an inclined well 4 (Figs. 1, 2), for example, at an angle of 45 °.

For example, the connecting dimension of the bottom flange 3 of the preventer 1: D = 300 mm.

The device is equipped with a replaceable ring 5 (Fig. 1, 3, 4). On top of the replaceable ring 5, the lower flange 3 of the preventer 1 is installed with the possibility of hermetic fastening with it using a sealing metal ring 6 (Figs. 1, 2, 3) and a bolt connection 7 (shown in Fig. 1 conditionally), for example, using 6- whith bolts.

The connecting dimension (D = 300 mm) of the lower flange 3 corresponds to the center-to-center diameter (D = 300 mm) of the bolt connection 7, made from the top in the replaceable ring 5.

Bottom replaceable ring 5 is installed on the support flange 8 (Fig. 1, 2, 4) of the wellhead assembly of the inclined well 4 with the possibility of hermetic fastening using a sealing metal ring 9 (Fig. 1, 2, 4) with a bolted connection 10 (in Fig. 1 and 2 are shown conditionally), for example, using 12 bolts.

The connecting size of the support flange 8 (D ₁ = 445 mm) of the wellhead of the inclined well 4 corresponds to the center-to-center diameter (D ₁ = 445 mm) of the bolted connection 10, made from below in the replaceable ring 5.

The device is equipped with a pipe holder 11 (see Fig. 2) of the first row of the pipe string 12 (see Fig. 1 and 2).

The lower flange 13 (Fig. 2) of the pipe hanger 11 is installed from below on the support flange 8 of the wellhead assembly of the inclined well 4 with the possibility of hermetic fastening using a sealing metal ring 9 with a bolted joint 10 (Figures 1 and 2 are shown conditionally), for example, using 12 bolts (see Fig. 1, 2).

The connecting size of the lower flange 13 of the pipe hanger 11 (D ₁ = 445 mm) corresponds to the center-to-center diameter (D ₁ = 445 mm) of the bolted connection 10 made in the support flange 8 of the wellhead assembly of the inclined well 4.

On top of the pipe holder 11, threaded holes 14 are diametrically made (Fig. 2), for example, in the amount of 6 pieces with connecting (D = 300 mm) using bolts 15 in the amount of 6 pieces and a sealing (sealing metal ring 6) of size corresponding to the connection size (D = 300 mm) of the bottom flange 3 of the preventer 1.

The device is equipped with a centralizer 16 '(see Fig. 1), installed inside the device before attaching the preventer 1 to the support flange 8 of the wellhead assembly of the inclined well 4.

Also, the device is equipped with a centralizer 16 "(see Fig. 2), installed inside the device before attaching the preventer 1 to the tube holder 11 of the first row of pipe string 12.

The inner diameters of the centralizers 16 'and 16 "are determined empirically, depending on the diameter of the first row of the pipe string 12 or the second row of the pipe string 17, lowered into the inclined well 4.

The lower and upper ends of the centralizers 16 'and 16 "are equipped with chamfers (in Figs. 1 and 2 it is shown conditionally).

The device works as follows.

The SVN deposit is developed by steam injection horizontal wells with an inclined head at an angle of 45 ° with a double-row pipe string, and the supporting flanges of the wellhead fittings of such wells have various standard sizes on which the device must be attached.

Before the operation of the device, the inner diameter of the centralizers 16 'and 16 "is selected, depending on the standard size of the first 12 and second 17 rows of the pipe string.

For example, the first row of the pipe string is used to inject steam with a temperature of 220-250 °, and the second row of the pipe string 17 is used for withdrawing heated oil using a pump (not shown in FIGS. 1-4).

Let's take the outer diameter of the first row 12 of the pipe string equal to 89 mm (according to GOST 633-80), and the outer diameter of the second row 17 of the pipe string equal to 60 mm.

Diameter D_qi replaceable centralizer 16 'or 16 " must be greater than the diameter of the coupling of the first row 12 or the second row 17 of the pipe string by the value ∆d = 10 mm (determined empirically from the results of tests at the head of an inclined well 4), i.e. the annular gap between the pipe string coupling and the 16 'or 16 "inner diameter of the centralizer is equal to:

D_qi= D_mi + 2 ∆d (one)

where D _mi - outer diameter of a pipe string coupling with a diameter d _i , mm;

∆d is the annular gap between the axial channel of the device and the coupling of the first row 12 or the second row 17 of the pipe string, as indicated above, let us assume ∆d = 10 mm.

Let's select the inner diameter of the centralizer 16 ', since the first row of 12 tubing strings (tubing) has a diameter d ₁ = 89 mm, so according to GOST 633-80, and the diameter of its coupling D _m1 = 108 mm, then substituting into formula 1 we get the inner diameter of the centralizer 16 ':

D _c1 = D _m1 + 2 ∆d _m1 = 108 mm + (2 10 m) = 128 mm.

Let's select the inner diameter of the centralizer 16 ", since the second row 17 of the tubing string has a diameter d ₂ = 60 mm, so according to GOST 633-80, and the diameter of its coupling D _m1 = 73 mm, then substituting into formula 1 we get the inner diameter of the centralizer 16" :

D _c1 = D _m1 + 2 ∆d _m1 = 73 mm + (2 10 mm) = 93 mm.

It has been experimentally established that the length of the chamfers made on the upper and lower ends of the 16 'and 16 "centralizers should be 2-3 times longer than the length of the chamfers on the couplings of the first 12 and second 17 rows of the pipe string. For example, on the couplings of the first 12 and the second 17 row of the pipe string of the chamfer has a size of 10 × 45 °, then on the upper and lower ends of the centralizers 16 'and 16 "we perform chamfers with dimensions = (10⋅3) × 45 ° = 30 × 45 °.

Thus, when the above condition is fulfilled, the chamfers made on the upper and lower ends of the centralizers 16 'and 16 "(see Figs. 1 and 2) ensure the unhindered (without snagging) movement of the first 12 and second 17 rows of the pipe string through the axial channel devices during the STR.

The selected inner diameters of the centralizers and the sizes of their upper and lower chamfers reduce the duration of work when carrying out trials with pipe strings in an inclined well, since, firstly, they ensure the centering of the pipe string relative to the axial channel of the device, and secondly, they exclude the clutches of the first couplings. 12 and the second 17 row of the pipe string for the device in the process of carrying out trials with them.

The device is equipped with two slings 18 (Fig. 1, 2) of different lengths a and b for lifting and installing the preventer 1 on the support flange 8 of the wellhead assembly of the inclined well 4 and the pipe hanger of the first row of the pipe string 12.

The difference between the length of the lines a and b is determined depending on the distance - c between the lifting lugs 2 'and 2 "of the preventer 1. For example, c = 350 mm = 0.35 m. Then, with the length of the branch a = 2 m, the line 18, the length of the branch b sling 18 will be equal to: b = a + c = 2 m + 0.35 m = 2.35 m.

On the inner surfaces 19 'and 19' (see Fig. 3 and 4) of the metal sealing rings 6 and 9, respectively, there are high-temperature sealing rings 20 'and 20 "made of fluoroelastomer FRM with a thickness of h = 5 mm.

FPM rings are highly resistant to chemicals. Fluoroelastomer (FPM) also has good physical and mechanical properties, such as elasticity, wear resistance. FPM retains its properties under the influence of chemically active substances, it is able to function in conditions of both positive and negative temperatures, namely from -40 ° C to + 300 ° C. High-temperature sealing rings 20 'and 20 "made of FRM fluoroelastomer are manufactured by OOO Vysota, Russian Federation, Samara region, Togliatti.

High-temperature sealing rings 20 'and 20 ", installed on the inner surfaces of the corresponding metal sealing rings 6 and 9, provide additional sealing of the device during its operation in the steam injection wells of the EHV at high temperatures from -40 ° C to + 300 ° C.

To fasten the first row of the pipe string at the mouth of the inclined well 4 (see Fig. 2), a threaded connection 21 is made in the pipe hanger channel 11 (Fig. 2).

Install in the preventer 1 (see Fig. 1) pipe rams 22 'and 22 "under the outer diameter of the first row 12 of the pipe string, mount the device as shown in figure 1. Launch the first short, for example, 800 m long, row of pipe string with the maximum outer diameter, for example, a tubing string with a diameter of 89 mm in an inclined well 4 through the axial bore of the device.

After lowering the first row 12 of the pipe string into the inclined well 4, fix the upper end of the first row 12 of the pipe string in the channel of the pipe hanger 11, for example, using a threaded connection 21. Mount the pipe blower 11 (see Fig. 2) of the first row 12 of the pipe string on the support flange 8 of the wellhead fittings of inclined well 4 as shown in figure 2. Then install in the preventer 1 pipe rams 23 'and 23 "(see figure 2) under the outer diameter of the first row 12 of the pipe string, fix the preventer 1 with the lower flange 3 into the threaded holes 14 made on the upper end of the pipe hanger 11.

Run the second long row 17, for example, 1200 m long, of a pipe string with a minimum outer diameter, for example, a tubing string with a diameter of 60 mm, into an inclined well 4 through the axial bore of the device.

Dismantle the preventer 1 from the pipe hanger. Trim the wellhead equipment and put the well into operation. Raise the first and second rows of pipe strings in the reverse order as described above.

In the process of sequential tripping with the first row 12 and the second row 17 of the pipe strings, OGWP may occur from the inclined well 4 at the wellhead. To eliminate OGVP, it is necessary to seal the space between the preventer and the pipe string 12 or 17 and the pipe rams 22 'and 22' '(see Fig. 1) and 23' and 23 "(see Fig. 2) devices, as well as take the necessary technological measures to eliminate blowout phenomena, i.e. to close the inner space of the first 12th row and the second 17th row of the pipe string.

To seal the wellhead, with the first 12 or second 17 row of the pipe string lowered, the handwheels of the manual drives (in Figs. 1 and 2 are shown conditionally) of the corresponding pipe rams 22 'and 22 "or 23' and 23", respectively, clockwise on 10-12 turns. As a result, the pipe rams 22 'and 22 "or 23' and 23" move radially inward and wrap around the first 12 or second 17 row of the pipe string around its entire circumference. The wellbore fluid pressure arising under the pipe rams 22 'and 22' 'or 23' and 23 "tightly compresses the pipe rams 22 'and 22" 23' and 23 "to the outer surface of the first 12 or second 17 row of the pipe string, i.e. the space between the device and the first 12 or second 17 row of the pipe string is sealed.

To overlap the internal space of the first 12 or second 17 row of the pipe string at the mouth of the inclined well 4, a shut-off member is screwed onto the upper end of the first 12 or second 17 row of the pipe string, for example, a ball valve (not shown in Figs. 1-4) of any known design (for example , brand KSH 70x21) and by turning the handle of the ball valve, for example, at an angle of 90 ° in the clockwise direction, overlap its internal flow section. As a result, the internal space of the first 12 or second 17 row of the pipe string is sealed and the OGVP is eliminated.

After the liquidation of the NGVP, i.e. after the pressure in the well is released, the device is opened, i.e. depressurize the space between the device and the first 12 or second 17 row of the pipe string and restore the internal space of the first 12 and second 17 rows of the pipe string.

First, the axial channel of the device is opened. To do this, rotate the handwheels of the manual drives in the counterclockwise direction by 10–12 revolutions to remove the pipe rams 22 'and 22' 'or 23' and 23 '' until the axial channel of the device is completely opened, i.e. return the pipe rams to the position shown in FIGS. 1 and 2.

Next, by turning the handle of the ball valve in the counterclockwise direction by an angle of 90 °, open the ball valve and, after making sure that there is no release of NGVP along the first 12 or second 17 row of the pipe string, unscrew the ball valve from the upper end of the first 12 or second 17 row of the pipe string and restore the internal space the first 12 or second 17 row of the pipe string.

The reliability of the device is increased, the high-temperature sealing rings installed on the inner surfaces of the metal sealing rings eliminate the loss of the preventer tightness in the place where the preventer is attached to the wellhead assembly of an inclined well through metal sealing rings at high temperatures from –40 to + 300 ° С.

The device has the ability to adjust the angle of inclination of the preventer when it is installed on the support flange of the wellhead depending on the angle of inclination of the inclined well, since the lifting lugs are fixed in the preventer with an offset in height relative to each other with the possibility of installing the preventer at the wellhead of the inclined well strictly at a certain angle , for example 45 °.

The selected inner diameters of the centralizers and their upper and lower chamfers reduce the duration of work when carrying out trials with pipe strings in an inclined well, since they provide centering of the pipe string relative to the axial channel of the device and exclude hooks on the device during the trials of the first 12 and second 17 rows of the string pipes.

The technological capabilities of the device are expanded when conducting trips with pipe strings in an inclined well, since the device allows sequential lowering of two pipe strings into one well with any standard size of the wellhead support flange.

A device for sealing the mouth of an inclined well during tripping and lifting operations of a two-row pipe string allows:

- to improve the reliability of the device;

- adjust the angle of inclination of the preventer when installing it on the support flange of the wellhead assembly in an inclined well;

- to reduce the duration of work when carrying out trials with a pipe string in an inclined well;

- to expand the technological capabilities of the device when carrying out a sequential trip with two pipe strings in an inclined well.

Claims (1)

A device for sealing the mouth of an inclined well during tripping and lifting operations of a double-row pipe string, containing a preventer with lifting lugs and a cast bottom flange made with a connecting and sealing size corresponding to the minimum dimensions of an attachment at the mouth of an inclined well, the device is equipped with a replaceable ring, on top of a replaceable ring installed under the bottom flange of the preventer with the possibility of hermetic fastening with it using a sealing metal ring and a bolted connection, the connecting size of the lower flange corresponds to the center-to-center diameter of the bolted connection made from the top in the replaceable ring, from the bottom the replaceable ring is installed on the support flange of the wellhead assembly of the inclined well with the possibility fastening by means of a sealing metal ring with a bolted connection, the connecting size of the supporting flange of the directional wellhead equipment corresponds to the center-to-center diameter bolted connection made from the bottom in a replaceable ring, characterized in that the device is equipped with a pipe hanger for the first row of the pipe string, and the lower flange of the pipe hanger is attached to the bottom flange of the wellhead, while on top of the pipe hanger there are diametrically made threaded holes with a connecting and sealing size corresponding to the connecting and the sealing size of the bottom flange of the BOP, the device is equipped with centralizers installed in the device before attaching the BOP to the support flange of the wellhead or pipe hanger, while the inner diameters of the centralizers depend on the diameters of the double-row pipe string running into the deviated well, and the lower and upper ends of the centralizers are chamfered , and on the inner surfaces of the metal sealing rings, high-temperature sealing rings made of fluorocarbon rubber FRM with a thickness of 5 mm are installed, and the device is equipped with two slings of different lengths for installing The ventor to the wellhead support flange and the pipe hanger, while the difference between the length of the lines depends on the distance between the lifting lugs of the preventer, and a shut-off element is used to seal the internal space of the first and / or second row of pipe strings.

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