Float collar

Abstract

The invention relates to a float collar. The float collar comprises a first barrel used for being connected with a sleeve and a second barrel arranged in the first barrel. A first flow channel is arranged in the first cylinder. A through hole is formed in the second barrel and used for being communicated with the outlet end of the first flow channel. And an acting seat is also arranged in the second cylinder body. The acting seat is constructed to be capable of being connected with an acting part so that the acting part can push the second barrel body to move downwards relative to the first barrel body, the through hole and the outlet end of the first flow channel can be staggered in the axial direction, and therefore communication between the first flow channel and the through hole is cut off. The acting piece can be a pressure building ball, a hollow rubber plug, a well cementation insertion head and the like, so that communication between the first flow channel and the through hole is cut off in a pressure building or mechanical pressing mode, the universality of the float collar is improved, and limitation of the well cementation technology is avoided. And specific steps or specific tools do not need to be added on the basis of the original construction process, so that the applicability of the float collar is improved.

Description

Technical Field

[0001] The invention relates to the technical field of well cementing, and in particular to a floating collar. Background Art

[0002] For formations with rapid salt creep, quickly lowering the casing to the designed position is a key factor in ensuring the quality of the wellbore. If grouting is not done in time during casing lowering, the check valve may fail or the casing may be squeezed and deformed due to excessive pressure difference. Therefore, it is particularly important to grout quickly during casing lowering. However, manual grouting or top drive grouting requires a lot of time to operate, and may even cause the grouting joint to fall into the well during operation, or the drilling fluid may overflow to the drilling platform due to failure to close the valve in time, increasing the safety risk of slipping of personnel at the wellhead. At present, there are many types of floating collars used for cementing, but these floating collars have poor versatility and are easily restricted by cementing processes when used. Summary of the invention

[0003] Based on the above problems existing in the prior art, the present invention provides a floating collar, which has good versatility and applicability and is not limited by cementing technology.

[0004] The technical solution adopted by the present invention to solve the technical problem is: to provide a floating collar, comprising:

[0005] A first cylinder, used for connecting the sleeve, wherein a first flow channel is provided inside the first cylinder; and

[0006] The second cylinder is arranged inside the first cylinder, and a through hole is provided on the second cylinder for connecting with the outlet end of the first flow channel, and an action seat is also provided inside the second cylinder.

[0007] Wherein, the action seat is configured to engage with the action member so that the second cylinder can be pushed downward relative to the first cylinder by the action member, so that the outlet end of the through hole and the first flow channel are staggered in the axial direction, thereby cutting off the connection between the first flow channel and the through hole.

[0008] Furthermore, a shear pin is provided between the first cylinder and the second cylinder, and the second cylinder can move downward relative to the first cylinder after the shear pin is sheared.

[0009] Furthermore, a mounting portion is provided on the first cylinder, a mounting hole for mounting the second cylinder is provided on the mounting portion, a retaining groove is provided on the hole wall of the mounting hole, and the retaining groove is configured to be able to engage with a retaining piece provided on the second cylinder after the second cylinder moves downward relative to the first cylinder.

[0010] Furthermore, a back-pressure valve is provided at the lower end of the mounting hole, and the back-pressure valve is configured to enable cement slurry to flow only from the casing through the second flow channel in the second cylinder into the annulus between the casing and the well wall during cementing operations.

[0011] Furthermore, the back-pressure valve is hinged at the lower end of the mounting portion.

[0012] Furthermore, a sealing ring is provided between the outer wall of the second cylinder and the inner wall of the mounting hole.

[0013] Furthermore, the working member is a pressure-holding ball, a hollow rubber plug or a cementing insertion head.

[0014] Furthermore, the pressure-holding ball is configured to destroy the action seat after the second cylinder moves downward relative to the first cylinder, so as to fall to the bottom of the well.

[0015] Furthermore, the hollow rubber plug is configured to enable the second flow channel in the second cylinder to be unblocked after the second cylinder moves downward relative to the first cylinder.

[0016] Furthermore, the cementing insert is connected to the drilling tool, so that the second cylinder is moved downward relative to the first cylinder by mechanical downward pressure through the drilling tool and the cementing insert.

[0017] The beneficial effect of the present invention is as follows: a floating collar provided by the present invention comprises a first cylinder for connecting a casing and a second cylinder arranged inside the first cylinder. A first flow channel is arranged inside the first cylinder. A through hole is arranged on the second cylinder for connecting the outlet end of the first flow channel. An action seat is also arranged in the second cylinder. The action seat is configured to engage with an action member so that the second cylinder is pushed downward relative to the first cylinder by the action member, so that the through hole and the outlet end of the first flow channel are offset in the axial direction, thereby cutting off the connection between the first flow channel and the through hole. The action member can be a pressure-holding ball, a hollow rubber plug, a cementing insertion head, etc., so as to cut off the connection between the first flow channel and the through hole by pressure-holding or mechanical downward pressure, thereby improving the versatility of the floating collar and avoiding being restricted by the cementing process. Moreover, there is no need to add specific steps or use specific tools on the basis of the original construction process, thereby improving the applicability of the floating collar. In addition, the first flow channel and the through hole can ensure that the drilling fluid in the annulus can smoothly enter the casing during the process of lowering the casing, thereby ensuring the circulation displacement of the drilling fluid. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0019] Figure 1Shown is a structural cross-sectional view of a floating collar.

[0020] Figure 2 Shown Figure 1 The structure of the floating collar in the first embodiment is shown in cross-sectional view.

[0021] Figure 3 Shown Figure 1 The structure of the floating collar in the second embodiment is shown in cross-sectional view.

[0022] Figure 4 Shown Figure 1 The structure sectional view of the floating collar in the third embodiment is shown.

[0023] Among them, the reference numerals in the figure are: 100, floating hoop; 10, first cylinder; 101, first flow channel; 11, first end; 12, second end; 13, mounting portion; 131, mounting hole; 132, stop groove; 14, back pressure valve; 141, abutment surface;

[0024] 20. Second cylinder; 201. Through hole; 202. Second flow channel; 21. Limiting portion; 22. Sealing ring; 23. Stop member; 24. Shear pin; 25. Action seat.

[0025] 30. Actuating part; 31. Pressure-holding ball; 32. Hollow rubber plug; 321. Diaphragm; 33. Cementing insert. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is now described in detail in conjunction with the accompanying drawings. This figure is a simplified schematic diagram, which only illustrates the basic structure of the present invention in a schematic manner, so it only shows the composition related to the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] refer to Figure 1As shown, a floating collar 100 provided by the present invention includes a first cylinder 10 and a second cylinder 20 arranged inside the first cylinder 10. The first cylinder 10 is internally configured with a first flow channel 101, which is used to allow the drilling fluid in the annulus between the casing and the well wall to flow into the casing through the second cylinder 20 during the process of lowering the casing (not shown in the figure). The second cylinder 20 is provided with a through hole 201, so that the drilling fluid in the first flow channel 101 enters the casing after flowing into the second flow channel 202 in the second cylinder 20, thereby ensuring that the casing can be quickly lowered to the designed position underground. Among them, the second cylinder 20 is configured to be able to move in the axial downward direction relative to the first cylinder 10 under the action of an external force, so that the through hole 201 and the outlet end of the first flow channel 101 are staggered in the axial direction, thereby disconnecting the communication between the through hole 201 and the first flow channel 101, so as to carry out subsequent cementing operations. Among them, the external force can be generated by the action member 30. The acting member 30 includes but is not limited to a pressure holding ball 31, a hollow rubber plug 32 and a cementing inserting head 33. This can effectively improve the versatility of the floating collar 100 and avoid being restricted by cementing technology during use.

[0028] Combination Figure 1 As shown, in some embodiments, the first cylinder 10 includes a first end 11 for connecting to the end of the casing, a second end 12 opposite to the first end 11, and a mounting portion 13 arranged between the first end 11 and the second end 12. The mounting portion 13 is provided with a mounting hole 131 that penetrates in the axial direction for mounting the second cylinder 20. A back pressure valve 14 is provided at the lower end opening of the mounting hole 131, and the back pressure valve 14 is configured to allow the fluid to flow in the second flow channel 202 of the second cylinder 20 in the axial downward direction only, but not in the axial upward direction. In this way, during the cementing process, the cement slurry can only flow into the annulus from the casing through the second cylinder 20 and the back pressure valve 14, but cannot flow into the interior of the casing through the back pressure valve 14 and the second cylinder 20.

[0029] In some embodiments, the back-pressure valve 14 is a tongue-type structure. The back-pressure valve 14 can be hinged to the lower end of the mounting portion 13 by a pin, and can unidirectionally block the lower end of the mounting hole 131 under the action of an elastic member (not shown in the figure). In this way, the fluid can only enter the second cylinder 20 in the axially downward direction and flow in the second flow channel 202 in the axially downward direction. Preferably, the elastic member can be a torsion spring arranged on the pin. In addition, the tongue-type back-pressure valve 14 can be closed under the action of the pressure difference to avoid the elastic member from plastically deforming or being stuck by sand and gravel in the well, which makes it impossible to reset the back-pressure valve 14.

[0030] In some embodiments, the back pressure valve 14 is provided with an abutment surface 141, which is used to abut the lower end surface of the mounting portion 13 and / or the lower edge of the mounting hole 131 under the action of the elastic member, thereby achieving one-way blocking of the mounting hole 131. Figure 1 As shown, in this embodiment, the back pressure valve 14 is substantially in a truncated cone structure. The abutting surface 141 is a truncated cone surface abutting against the lower edge of the mounting hole 131 .

[0031] Combination Figure 1 As shown, in some embodiments, the inlet end of the first flow channel 101 is arranged on the lower end surface of the mounting portion 13, and the outlet end of the first flow channel 101 faces the mounting hole 131 so as to communicate with the through hole 201 of the second cylinder 20. In this embodiment, the first flow channel 101 extends in the axially upward direction and then in the radially inward direction. A plurality of first flow channels 101 may be provided, and the plurality of first flow channels 101 are evenly arranged in the circumferential direction of the mounting hole 131.

[0032] Combination Figure 1 As shown, in some embodiments, a limiting portion 21 is provided at the upper end of the second cylinder 20 for abutting against the upper end surface of the mounting portion 13. In addition, the limiting portion 21 can also engage with the action member 30 so as to push the second cylinder 20 to move in the axially downward direction. A sealing ring 22 is provided on the outer wall of the second cylinder 20 so as to form a sealed fit between the outer wall of the second cylinder 20 and the hole wall of the mounting hole 131. In some of the embodiments, a stop member 23 is also provided on the outer wall of the second cylinder 20. The stop member 23 is configured to be able to engage with the stop groove 132 provided on the hole wall of the mounting hole 131 when the limiting portion 21 abuts against the upper end surface of the mounting portion 13, thereby preventing the second cylinder 20 from moving in the axially upward direction under the action of the fluid in the annulus. In the present embodiment, the stop member 23 is a stop retaining spring provided on the second mounting cylinder. When the limiting portion 21 abuts against the upper end surface of the mounting portion 13 , the retaining member 23 extends radially outward into the retaining groove 132 so as to form a snap fit with the retaining groove 132 .

[0033] In some embodiments, a shear pin 24 is further provided on the outer wall of the second cylinder 20 for connecting the first cylinder 10 and the second cylinder 20. The shear pin 24 is configured to be sheared by the first cylinder 10 and the second cylinder 20 when the action member 30 applies an external force, so that the first cylinder 10 can move in an axially downward direction relative to the second cylinder 20, thereby disconnecting the through hole 201 from the first flow channel 101.

[0034] In some embodiments, an action seat 25 is provided on the inner wall of the second cylinder 20. The action seat 25 is configured to engage with the action member 30 so that under the action of the external force, the first cylinder 10 moves in the axial downward direction relative to the second cylinder 20. The second flow channel 202 inside the second cylinder 20 passes through the action seat 25 so that the drilling fluid in the annulus enters the casing and the cement slurry flows into the annulus during the cementing operation.

[0035] In some embodiments, when the casing is lowered into the well, the back pressure valve 14 closes the lower end of the mounting hole 131 under the action of the pressure difference between the elastic member and the drilling fluid in the annulus and the casing, so that the drilling fluid in the annulus cannot directly enter the interior of the casing through the second flow channel 202. In this process, the drilling fluid in the annulus flows through the first flow channel 101 and the through hole 201 in sequence and enters the second flow channel 202 before flowing into the interior of the casing.

[0036] refer to Figure 2 As shown, in the first embodiment, the connection between the first flow channel 101 and the through hole 201 can be cut off by throwing a ball to hold the pressure. In this embodiment, the action member 30 is a holding pressure ball 31. The holding pressure ball 31 thrown from the wellhead enters the inside of the floating collar 100 under the action of gravity and engages with the action seat 25. At this time, the technician can pressurize at the wellhead to apply external force through the holding pressure ball 31 until the shear pin 24 is sheared by the first cylinder 10 and the second cylinder 20. Continue to pressurize, and push the second cylinder 20 to move in the axial downward direction relative to the first cylinder 10 through the holding pressure ball 31 and the action seat 25 until the stop member 23 enters the stop groove 132 and forms a snap fit. At this time, the through hole 201 and the outlet end of the first flow channel 101 are staggered in the axial direction to cut off the connection between the through hole 201 and the first flow channel 101. Continue to pressurize again, so that the action seat 25 is destroyed under the action of the holding pressure ball 31. The pressure holding ball 31 can fall to the bottom of the well through the action seat 25 and the back pressure valve 14 in sequence. In this way, the casing and the annulus can be connected in one direction through the second flow channel 202 and the back pressure valve 14 to facilitate subsequent cementing operations.

[0037] refer to Figure 3As shown, in the second embodiment, the connection between the first flow channel 101 and the through hole 201 can still be cut off by holding pressure. In this embodiment, the action member 30 is a hollow rubber plug 32. The hollow rubber plug 32 dropped from the wellhead can enter the interior of the floating collar 100 under the pressure of the drilling fluid, and the action seat 25 and / or the limiter 21 are engaged. At this time, the technician can pressurize at the wellhead until the shear pin 24 is sheared by the first cylinder 10 and the second cylinder 20. Continue to pressurize, and push the second cylinder 20 relative to the first cylinder 10 in the axial downward direction through the hollow rubber plug 32 until the stop member 23 enters the stop groove 132 and forms a snap fit. At this time, the through hole 201 and the outlet end of the first flow channel 101 are staggered in the axial direction to cut off the connection between the through hole 201 and the first flow channel 101. Continue to pressurize again, so that the diaphragm 321 of the hollow rubber plug 32 is destroyed under the action of pressure. In this way, the casing and the annulus can still be connected in one direction through the second flow channel 202 and the back pressure valve 14, so as to facilitate the subsequent cementing operation.

[0038] refer to Figure 4 As shown, in the third embodiment, the connection between the first flow channel 101 and the through hole 201 can be cut off by mechanical downward pressure. In this embodiment, the action member 30 is a cementing insert 33. The technician sends the cementing insert 33 into the floating collar 100 through the drilling tool, and engages with the action seat 25 and / or the limiter 21. The drilling tool is pressed down so that the cementing insert 33 pushes the second cylinder 20 relative to the first cylinder 10 in the axial downward direction after the shear pin 24 is cut off, until the stop member 23 enters the stop groove 132 and forms a snap fit. In this process, the through hole 201 and the outlet end of the first flow channel 101 are staggered in the axial direction so as to cut off the connection between the through hole 201 and the first flow channel 101. After the cementing insert 33 is retracted by the drilling tool, the casing and the annulus can still be connected in one direction through the second flow channel 202 and the back pressure valve 14 to facilitate subsequent cementing operations.

[0039] The beneficial effect of the floating collar 100 provided by the present invention is that, by providing the first flow channel 101 and the through hole 201, it can be ensured that the drilling fluid in the annulus can smoothly enter the casing during the lowering of the casing, thereby ensuring the circulation displacement of the drilling fluid. In addition, the connection between the first flow channel 101 and the through hole 201 can be cut off by holding pressure or mechanical downward pressure, thereby improving the versatility of the floating collar 100 and avoiding the limitation of the cementing process. Moreover, there is no need to add specific steps or use specific tools on the basis of the original construction process, thereby improving the applicability of the floating collar 100. In addition, since the back pressure valve 14 adopts a tongue-type structure, it can effectively prevent the elastic member from undergoing plastic deformation or being stuck by sand and gravel in the well, making it impossible to reset the back pressure valve 14.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, it can be a mechanical connection, it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front and back", "left and right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0042] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A floating collar, comprising: A first cylinder (10) is used for connecting the sleeve, wherein a first flow channel (101) is provided inside the first cylinder (10); and The second cylinder (20) is arranged inside the first cylinder (10), and the second cylinder (20) is provided with a through hole (201) for connecting with the outlet end of the first flow channel (101). The second cylinder (20) is also provided with an operating seat (25). in, The action seat (25) is configured to engage with the action member (30) so as to push the second cylinder (20) to move downward relative to the first cylinder (10) through the action member (30), so that the through hole (201) and the outlet end of the first flow channel (101) are offset in the axial direction, thereby cutting off the connection between the first flow channel (101) and the through hole (201).

2. The floating collar according to claim 1, characterized in that: A shear pin (24) is provided between the first cylinder (10) and the second cylinder (20), and the second cylinder (20) can move downward relative to the first cylinder (10) after the shear pin (24) is sheared.

3. The floating collar according to claim 1, characterized in that: The first cylinder (10) is provided with a mounting portion (13), the mounting portion (13) is provided with a mounting hole (131) for mounting the second cylinder (20), a retaining groove (132) is provided on the hole wall of the mounting hole (131), and the retaining groove (132) is configured to be able to engage with a retaining member (23) provided on the second cylinder (20) after the second cylinder (20) moves downward relative to the first cylinder (10).

4. The floating collar according to claim 3, characterized in that: A back-pressure valve (14) is provided at the lower end of the mounting hole (131), and the back-pressure valve (14) is configured to enable cement slurry to flow only from the casing through the second flow channel (202) in the second cylinder (20) into the annulus between the casing and the well wall during cementing operations.

5. The floating collar according to claim 4, characterized in that: The back pressure valve (14) is hinged to the lower end of the mounting portion (13).

6. The floating collar according to claim 3, characterized in that: A sealing ring (22) is provided between the outer wall of the second cylinder (20) and the inner wall of the mounting hole (131).

7. The floating collar according to any one of claims 1 to 6, characterized in that: The action member (30) is a pressure-holding ball (31), a hollow rubber plug (32) or a cementing insert head (33).

8. The floating collar according to claim 7, characterized in that: The pressure-holding ball (31) is configured to destroy the action seat (25) after the second cylinder (20) moves downward relative to the first cylinder (10), so as to fall to the bottom of the well.

9. The floating collar according to claim 7, characterized in that: The hollow rubber plug (32) is configured to enable the second flow channel (202) in the second cylinder (20) to be unblocked after the second cylinder (20) moves downward relative to the first cylinder (10).

10. The floating collar according to claim 7, characterized in that: The cementing insert head (33) is connected to the drilling tool so that the second cylinder (20) is moved downward relative to the first cylinder (10) by mechanical downward pressure through the drilling tool and the cementing insert head (33).

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