Casing pipe floater with automatic compensation and hydraulic striker device

Abstract

The invention relates to the field of oil and gas exploration and development and downhole tools, in particular to a casing floater with an automatic compensation and hydraulic striker device, which comprises a body and a hydraulic striker mechanism, the hydraulic striker mechanism comprises a rupture disc arranged in the body and a support sleeve arranged below the rupture disc in the axial direction, and the support sleeve is connected with the body. A striker ring used for rupture of the rupture disc is arranged on the inner side of the supporting sleeve, and the striker ring and the supporting sleeve are axially connected in a nested mode through a shear pin, so that the initial position of the top of the supporting sleeve is higher than the top of the striker ring, and the supporting sleeve moves in the axial direction under the action of preset pressure. According to the invention, the effects of high loading capacity, strong adaptive capacity, more stable opening, full bore realization, well cementation quality guarantee and the like are realized.

Description

Technical Field

[0001] This invention relates to the fields of oil and gas exploration and development and downhole tools, specifically to a casing floater with an automatic compensation and hydraulic striker device. Background Technology

[0002] With the continuous deepening of oil and gas exploration and development, long horizontal wells and extended reach wells have become important directions for oil and gas field development. However, the casing installation operation of these wells faces many challenges, such as high frictional resistance between the casing and the wellbore and difficulty in casing installation.

[0003] The technical principle of floating casing is to use a casing floater and an anti-backpressure device to seal a section of air or other light medium at the tail of the casing string, thereby increasing the buoyancy of the casing string below the floater and reducing the pressure of the casing string on the well wall. This reduces friction during casing installation, improves the success rate of safe casing installation, and creates favorable conditions for casing installation in complex deep wells.

[0004] Casing floaters are mainly used in floating casing runs in horizontal wells with long horizontal sections and extended reach wells. Installed within the casing string and working in conjunction with a casing check valve, the floater traps a section of air or low-density drilling fluid within the casing string. This increases the buoyancy of the casing string below the floater, reduces frictional resistance between the casing string and the wellbore wall in the horizontal section, and improves the success rate of safe casing run-in.

[0005] Existing casing flotation devices mainly have three structures: sliding sleeve type floating coupling, locking block type floating coupling, and rupture disc type floating coupling. Although they can reduce the frictional resistance of the casing string to a certain extent, they have the following drawbacks: 1. Sliding sleeve type floating coupling (1) After the sliding sleeve is opened, the inner core remains inside the tool. When cementing is required, the rigid inner core is pushed to the bottom of the well using a rubber plug, which increases the risk of high pump pressure during cementing. (2) After the sliding sleeve is opened, the circulation channel is small, which affects the discharge rate of cementing construction and may affect the cementing quality; (3) In order to ensure that the inner core can pass smoothly through the long sleeve string, the inner diameter of the floating tool is designed to be smaller than the diameter of the sleeve, which damages the integrity of the sleeve string.

[0006] 2. Locking block type floating coupling (1) The temporary barrier and the main body are sealed by a rubber disc vulcanized on the inner core. The pressure bearing capacity is not high, and the seal is more likely to fail under the influence of the in-well excitation pressure. (2) After the temporary barrier is removed, the circulation channel is smaller, which affects the discharge rate of cementing construction and may affect the cementing quality; (3) During cementing, rubber plugs are used to push the inner core containing rigid parts to the bottom of the well. The outer diameter of the rigid parts and the clearance between them are small, which increases the risk of high pump pressure during cementing. 3. Rupture disc-type floating coupling (1) The temporary barrier is removed by pressure bursting of the rupture disc. After bursting, the debris is large and not easy to be carried out by circulation, which may cause circulation blockage. (2) After the rupture disc breaks, the inner diameter of the tool has a plateau step expansion space, which cannot achieve full bore, bringing risks to subsequent operations.

[0007] Therefore, in order to address the above problems, this invention proposes a casing floater with automatic compensation and hydraulic impact pin device to improve the pressure-bearing capacity of the temporary barrier, ensure the integrity of the casing string, and improve cementing quality. Summary of the Invention

[0008] To address the problem that existing technologies cannot achieve full bore after the temporary barrier is removed, this invention provides a casing floater with an automatic compensation and hydraulic striker device, which can automatically compensate for the expansion space and ensure that the tool's inner diameter matches the casing's inner bore after the temporary barrier is removed.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a sleeve floater with automatic compensation and hydraulic firing pin device, comprising a body, wherein a hydraulic firing pin mechanism is provided in the body, the hydraulic firing pin mechanism includes a rupture disc disposed in the body and a support sleeve disposed axially below the rupture disc, wherein a firing pin ring for rupturing the rupture disc is provided on the inner side of the support sleeve, and the firing pin ring and the support sleeve are axially nested and connected by shear pins, such that the initial position of the top of the support sleeve is higher than the top of the firing pin ring and moves axially under a preset pressure.

[0010] Furthermore, it also includes an automatic compensation mechanism located within the main body. The automatic compensation mechanism includes a limiting sleeve located inside the main body and a limiting sleeve spring fitted on the limiting sleeve. The limiting sleeve spring provides the power for the limiting sleeve to move downward. The inner diameter of the limiting sleeve is consistent with the inner diameter of the sleeve. The rupture disc is located between the top of the support sleeve and the bottom of the limiting sleeve.

[0011] Furthermore, the inner wall of the body has a raised step. When not in use, the upper end of the limiting sleeve abuts against the raised step to constrain the limiting sleeve and the limiting sleeve spring to move upward along the axial direction.

[0012] Furthermore, the inner wall of the body is equipped with a rupture disc packing to seal the gap between the rupture disc and the body.

[0013] Furthermore, a retaining spring is installed in the groove on the inner wall of the main body to constrain the axial movement of the retaining sleeve when it moves toward the striking pin ring.

[0014] Furthermore, the outer wall of the limiting sleeve and the inner wall of the main body are both provided with a first annular stepped groove, and the limiting sleeve spring is elastically compressed between the annular step surfaces of the two first annular stepped grooves.

[0015] Furthermore, one end of the impact pin ring is a flat annular surface, and the other end has multiple pointed tips protruding circumferentially. These pointed tips are used to allow the rupture disc to withstand localized edge pressure.

[0016] Furthermore, the inner wall of the support sleeve and the outer wall of the firing pin ring are provided with a second annular stepped groove, through which the support sleeve can move axially relative to the firing pin ring.

[0017] Furthermore, the lower end of the body is provided with a lower connector, and a lower connector packing is installed in the groove on the outer wall of the lower connector. The lower connector packing is used to seal the gap between the lower connector and the body.

[0018] Furthermore, at the threaded connection between the lower connector and the body, there are two circumferentially symmetrical screws to prevent the connecting threads from coming off.

[0019] In summary, the present invention has the following beneficial effects: (1) More stable opening: The casing floater designed in this invention opens by first breaking the impact pin. If the shear pin of the impact pin mechanism cannot be cut due to complex reasons, the pressure can be increased to directly break the rupture disc. The hydraulic impact pin device converts the pressure of the temporary barrier into the shearing force on the shear pin. After the shear pin is cut, the temporary barrier pushes the support ring downward under the pressure. The temporary barrier breaks under the local high pressure of the impact pin ring and is released. At the same time, the debris of the temporary barrier and the drilling fluid above the temporary barrier will move downward under the action of gravity, and the air below the temporary barrier will move upward to form displacement and exhaust. After the exhaust is completed, it will be circulated for two more cycles. During the circulation, the debris of the temporary barrier will be discharged with the circulating fluid.

[0020] (2) Achieving full bore: The inner diameter of the hydraulic striking pin mechanism and the inner diameter of the self-compensating mechanism of this invention are consistent with the inner diameter of the casing. After the mechanism is activated, the inner diameter remains unchanged. After the fracture disc is broken, the debris is small and can be discharged from the wellhead through circulating drilling fluid, automatically compensating for the enlarged diameter space required for the installation of the fracture disc. This ensures unobstructed flow channels, improves the displacement efficiency of cementing operations, enhances cementing quality, and reduces the risks of subsequent operations.

[0021] (3) Strong adaptability: According to the well conditions, the present invention can connect two or more casing floaters in a casing string so as to share the hydrostatic pressure of the drilling fluid in the upper part of the casing string. It can be applied to well conditions with deeper vertical depth and higher drilling fluid density.

[0022] Working principle: The hydraulic impactor mechanism inside the main body forms a temporary barrier. Utilizing the pressure buildup at the top of the temporary barrier, the hydraulic impactor converts the pressure of the temporary barrier into a shearing force on the shear pin. When the pressure reaches a certain value, the shear pin is sheared. Under the pressure, the temporary barrier pushes the support ring downwards. The limiting sleeve moves downwards along with the temporary barrier under the force of the limiting sleeve spring. When the temporary barrier contacts the upper end of the impactor ring, it breaks under local high pressure, and the temporary barrier is released. The limiting sleeve continues to move downwards under the force of the limiting sleeve spring until it contacts the upper end of the impactor ring and is locked by the snap ring, thus filling the enlarged diameter space for installing the temporary barrier. At the same time, the debris from the temporary barrier and the drilling fluid above the temporary barrier will move downwards under gravity, while the air below the temporary barrier will move upwards to form displacement and venting. After venting, the system circulates for two more cycles. During the circulation process, the debris from the temporary barrier is discharged with the circulating fluid, and the system enters the normal cementing procedure. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the casing floater of the present invention; Figure 2 This is a cross-sectional view of the casing floater body of the present invention; Figure 3 This is a schematic diagram of the hydraulic striking pin mechanism and automatic compensation mechanism of the casing floater of the present invention.

[0024] The annotations in the attached figures are explained as follows: 1. Body; 2. Limiting sleeve; 3. Limiting sleeve spring; 4. Snap ring; 5. Rupture disc; 6. Rupture disc packing; 7. Support sleeve; 8. Shear pin; 9. Impact pin ring; 10. Lower connector packing; 11. Lower connector; 12. Screw. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the embodiments.

[0026] Example 1: like Figure 1 , Figure 2 and Figure 3 As shown, a casing floater with automatic compensation and hydraulic firing pin device is installed in a casing string and specifically includes a body 1, in which a hydraulic firing pin mechanism is provided. The hydraulic striking pin mechanism includes a rupture disc 5 and a support sleeve 7 axially disposed within the body 1. The rupture disc 5 forms a temporary barrier within the body 1. The support sleeve 7 is located axially below the rupture disc 5, and an striking pin ring 9 for rupturing the rupture disc 5 is provided on the inner side of the support sleeve 7. The rupture disc 5 moves axially under pressure. The rupture disc 5 is opened by applying pressure to the rupture disc 5 so that its bottom contacts the striking pin ring 9 and ruptures. The striking pin ring 9 and the support sleeve 7 are nested together and connected by shear pins 8. The striking pin ring 9 is located inside the support sleeve 7, and after the shear pins 8 disconnect the connection between the striking pin ring 9 and the support sleeve 7, the support sleeve 7 moves axially to make way for the movement of the rupture disc 5. The initial position of the top of the support sleeve 7 is higher than the top of the striking pin ring 9 and moves axially under a preset pressure. This nested structure saves radial design space, ensures the wall thickness of the body 1 while ensuring that the outer diameter of the body 1 is suitable for wellbore running, and achieves that the strength of the body 1 is not lower than the strength of the applicable casing.

[0027] The casing floater provided by this invention is installed in the casing string. During casing installation, the use of the casing floater improves the safety and efficiency of casing installation. No grouting is performed below the casing floater, while normal grouting occurs above it. The casing floater works in conjunction with a casing check valve to enclose a section of air within the casing string. During casing string installation, the buoyancy of the hollow casing string significantly reduces the pressure of the casing string on the horizontal section of the well wall, and significantly reduces the friction in the horizontal section, ensuring the safe and smooth installation of the casing to the predetermined well depth.

[0028] Example 2: like Figure 1 , Figure 2 and Figure 3 As shown, a cannula floater with automatic compensation and hydraulic firing pin device based on Embodiment 1 specifically includes a body 1, in which a hydraulic firing pin mechanism and an automatic compensation mechanism are provided; The automatic compensation mechanism includes a limiting sleeve 2 located inside the main body 1, and a limiting sleeve spring 3 fitted on the limiting sleeve 2. The limiting sleeve spring 3 provides the power for the limiting sleeve 2 to move downward. The inner diameter of the limiting sleeve 2 is the same as the inner diameter of the casing. The fracture disc 5 is located between the top of the support sleeve 7 and the bottom of the limiting sleeve 2. In this way, after the casing floater is opened, the support sleeve 7 moves down with the limiting sleeve 2 to below the top of the impact ring 9. The inner wall of the limiting sleeve 2 has the same diameter as the inner wall of the impact ring 9 and is spliced ​​together, so that the inner diameter is the same as the inner diameter of the casing, keeping the circulation channel unchanged and improving the cementing quality.

[0029] The hydraulic striker mechanism inside the main body 1 forms a temporary barrier. Under pressure, the temporary barrier pushes the support ring downward. The limiting sleeve 2, under the force of the limiting sleeve spring 3, moves downward with the temporary barrier. When the temporary barrier contacts the upper end of the striker ring 9, it breaks under local high pressure, and the temporary barrier is released. The limiting sleeve 2 continues to move downward under the force of the limiting sleeve spring 3 until it contacts the upper end of the striker ring 9, where it is locked by the retaining spring 4, thus compensating for the enlarged diameter space required for installing the temporary barrier. The outer wall of the limiting sleeve 2 has a groove along the axial direction that mates with the retaining spring 4. When the limiting sleeve 2 moves into position, the retaining spring 4 engages with the groove.

[0030] Example 3: like Figure 1 , Figure 2 and Figure 3 As shown, a casing floater with automatic compensation and a hydraulic firing pin device according to Embodiment 2 specifically includes a body 1. The body 1 contains a hydraulic firing pin mechanism and an automatic compensation mechanism. The inner wall of the body 1 has a raised step. The hydraulic firing pin mechanism within the body 1 forms a temporary barrier. By applying pressure to the upper part of the temporary barrier within the body 1, the hydraulic firing pin device cracks the temporary barrier. When the casing floater is not activated, the upper end of the limiting sleeve 2 abuts against the annular raised step protruding from the inner wall of the body 1, constraining the limiting sleeve 2 and the limiting sleeve spring 3 to move axially upwards. When the upper end of the limiting sleeve 2 abuts against the annular raised step protruding from the inner wall of the body 1, the rupture disc 5 is in its initial position before opening, and the limiting sleeve 2 and the support sleeve 7 clamp the rupture disc 5. The firing pin ring 9 and the support sleeve 7 are axially nested together by shear pins 8. The shear pins 8 are broken according to a predetermined pressure. The number and strength of the shear pins 8 arranged along the circumference of the firing pin ring 9 allow the opening pressure to be adjusted according to applicable requirements. Among them, the inner wall of the main body 1 is provided with another annular stepped groove at the top of the rupture disc 5, which is used to restrict the rupture disc 5 from moving upward along the axial direction and to ensure the stability of the rupture disc 5 installation.

[0031] In practice, the inner wall of the body 1 is equipped with a rupture disc packing 6, which is used to seal the gap between the rupture disc 5 and the body 1.

[0032] One end of the impact ring 9 is a flat annular surface, while the other end has multiple pointed tips protruding circumferentially. These tips are used to subject the fracture disc 5 to localized edge pressure, causing the fracture disc 5 to fracture. The fracture disc 5 is made of a fragile material with a special formula and processing technology, which has higher pressure resistance and greater stability. After fracturing, the fragments are small (maximum unidirectional size less than 2mm), making it easy to discharge through circulating drilling fluid.

[0033] During implementation, a retaining spring 4 is installed in the groove on the inner wall of the main body 1. When the limiting sleeve 2 contacts the striking pin ring 9, it is used to restrain the axial movement of the limiting sleeve 2. At the same time, the outer wall of the limiting sleeve 2 and the inner wall of the main body 1 are provided with first annular stepped grooves. The limiting spring is located between the annular stepped surfaces of the two first annular stepped grooves, providing the axial downward movement power for the limiting sleeve 2. Similarly, it can also be used to restrain the extension of the limiting sleeve spring 3 after the rupture disc 5 is ruptured and after the limiting sleeve 2 has moved into place.

[0034] In implementation, the inner wall of the support sleeve 7 and the outer wall of the firing pin ring 9 are provided with a second annular stepped groove. The support sleeve 7 can move axially relative to the firing pin ring 9 through the second annular stepped groove. The distance between the annular step surfaces of the two second annular stepped grooves is greater than the distance from the bottom surface of the rupture disc 5 to its tip, which facilitates nested assembly and saves design space.

[0035] Example 4: like Figure 1 , Figure 2 and Figure 3 As shown, in the above embodiment, the connection between the body 1 and the sleeve is a threaded connection. Specifically, the upper inner wall of the body 1 has threads for connection with the sleeve during use. The lower end of the body 1 is provided with a lower connector 11, the upper end of which is threaded to the lower end of the body 1, and the lower outer wall of the lower connector 11 has threads for connection with the sleeve during use. At the threaded connection between the lower connector 11 and the body 1, there are two circumferentially symmetrical screws 12 to prevent the connecting threads from coming off. A lower connector packing 10 is installed in the groove on the outer wall of the lower connector 11, and two lower connector packing retaining rings can also be provided on both sides of the lower connector packing 10 to seal the gap between the lower connector 11 and the body 1. At the threaded connection between the lower connector 11 and the body 1, there are two circumferentially symmetrical screws 12 to prevent the connecting threads from coming off.

[0036] In the cementing and floating casing running process of extended-displacement horizontal wells, the casing floater provided by this invention is used. Due to the deep vertical depth and high drilling fluid density, two casing floaters are connected separately in the casing string (casing floater 1 is closer to the wellhead, and casing floater 2 is farther from the wellhead) to share the hydrostatic pressure, avoiding operation of the casing floaters under near-limit pressure conditions and ensuring the safety of the floating casing running operation. When the casing string is successfully run to the predetermined well depth, casing floater 1 bears the hydrostatic pressure at its depth to the wellhead, and casing floater 2 bears the hydrostatic pressure at the height between casing floaters 1 and 2. The opening pressure of casing floater 1 is reached through the pressure buildup in the wellhead pipe, and casing floater 1 opens, the pipe passage is unobstructed, and casing floater 2 instantly bears the hydrostatic pressure at its height to the wellhead, exceeding its own opening pressure, and casing floater 2 opens. Grouting continues to be injected into the casing string, and the drilling fluid above casing floater 2 displaces the air below casing floater 2, expelling the air. After sufficient circulation, the normal cementing procedure begins.

[0037] In specific implementation, the casing floater of the present invention can be carried out according to the following steps: a. Connect the casing string guide device and casing check valve according to the design. Fill the area below the casing check valve with drilling fluid, and leave the area above the casing check valve unfilled with drilling fluid. b. After reaching a certain well depth, connect the casing floater into the casing string according to the design, ensuring a firm connection and reliable sealing; c. Continue lowering the casing string and proceed with normal grouting; d. After the casing string is lowered to the predetermined well depth, pressure is applied from the wellhead into the casing string. e. When the pressure reaches the opening pressure of the casing floater, the casing floater opens, the temporary barrier inside the casing is removed, and the circulation channel is unblocked. The temporary barrier is opened by the rupture disc 5 impacting the upper tip of the striker ring 9 under pressure. During this process, the rupture disc 5 always bears the weight of the upper drilling fluid to ensure that the impact force is sufficient to break the rupture disc 5, thus ensuring the stability of the casing floater opening.

[0038] f. Continue grouting into the casing string. The drilling fluid above the casing floater will displace the air below the casing floater, thus expelling the air. g. After sufficient circulation, proceed with the normal cementing procedure.

[0039] In summary, the casing floater with automatic compensation and hydraulic striker device of this invention, through material optimization and structural design, achieves high pressure resistance, strong adaptability, more stable opening, full-bore operation, and guaranteed cementing quality. In practical applications, it can significantly improve the safety and efficiency of casing running operations, reduce operating costs, and provide strong technical support for oil and gas exploration and development. Furthermore, this invention has a simple structure, is easy to operate, and has high reliability, possessing broad application prospects and market potential.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A casing float with automatic compensation and hydraulic ram device, characterized in that, The application relates to a hydraulic ram mechanism, which comprises a body (1) provided with a rupture disc (5) arranged in the body (1), a supporting sleeve (7) arranged axially below the rupture disc (5), a ram ring (9) arranged in the inner side of the supporting sleeve (7) and used for rupture of the rupture disc (5), and a shear pin (8) axially connecting the ram ring (9) and the supporting sleeve (7) and enabling the supporting sleeve (7) to move axially under the action of a preset pressure.

2. A casing float with automatic compensation with hydraulic means according to claim 1, characterized in that, The application further comprises an automatic compensation mechanism arranged in the body (1), which comprises a limiting sleeve (2) arranged in the inner side of the body (1) and a limiting sleeve spring (3) sleeved on the limiting sleeve (2) and providing power for downward movement of the limiting sleeve (2), the inner diameter of the limiting sleeve (2) is consistent with the inner diameter of the sleeve, and the rupture disc (5) is arranged between the top of the supporting sleeve (7) and the bottom of the limiting sleeve (2).

3. A casing float with automatic compensation with hydraulic means according to claim 2, characterized in that, The inner wall of the body (1) is provided with a convex step, the upper end of the limiting sleeve (2) abuts against the convex step, and the limiting sleeve (2) and the limiting sleeve spring (3) are prevented from moving axially upward.

4. A casing float with automatic compensation with hydraulic means according to claim 2, characterized in that, The inner wall of the body (1) is provided with a rupture disc packing (6) for sealing the gap between the rupture disc (5) and the body (1).

5. A casing float with automatic compensation with hydraulic means according to claim 2, characterized in that, The clamping spring (4) is arranged in the clamping groove in the inner wall of the body (1) and is used for limiting the axial movement of the limiting sleeve (2) when the limiting sleeve (2) moves towards the ram ring (9).

6. A casing float with automatic compensation of the hydraulic device according to claim 4, characterized in that The outer wall of the limiting sleeve (2) and the inner wall of the body (1) are both provided with a first annular stepped groove, and the limiting sleeve spring (3) is arranged in an elastic compression mode between the annular stepped surfaces of the two first annular stepped grooves.

7. A casing float with automatic compensation with hydraulic means according to claim 1, characterized in that, One end of the ram ring (9) is a flat annular surface, and the other end is provided with a plurality of sharp ends protruding in the circumferential direction, and the sharp ends are used for enabling the rupture disc (5) to bear local edge pressure.

8. A casing float with automatic compensation of the hydraulic device according to claim 7, characterized in that The inner wall of the supporting sleeve (7) and the outer wall of the ram ring (9) are provided with a second annular stepped groove, and the supporting sleeve (7) can move axially relative to the ram ring (9) through the second annular stepped groove.

9. The casing float with automatic compensation of the hydraulic device according to claim 1, characterized by the fact that The lower end of the body (1) is provided with a lower connector (11), the outer wall of the lower connector (11) is provided with a clamping groove, and the lower connector packing (10) is arranged in the clamping groove of the outer wall of the lower connector (11) and is used for sealing the gap between the lower connector (11) and the body (1).

10. A casing float with automatic compensation of the hydraulic device according to claim 9, characterized in that The threaded connection part of the lower connector (11) and the body (1) is provided with two circumferentially symmetrical screws (12) for preventing the threaded connection from being unscrewed.

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