Self-locking float collar float shoe and well cementing pressure self-adaptive adjusting device thereof

Abstract

This invention relates to the field of cementing pressure regulation technology, and discloses a self-locking float collar / float and its cementing pressure adaptive regulation device. The self-locking float collar / float cementing pressure adaptive regulation device includes a float guide cap, a pipe body disposed at the bottom of the float guide cap, a perforated collar disposed inside the pipe body, a one-way valve assembly disposed within the perforated collar, a flow-blocking plate disposed on one side of the one-way valve assembly, a flow groove formed within the flow-blocking plate, and one side of the one-way valve assembly abutting against the middle of the flow-blocking plate. It also includes a pressure regulating unit disposed within the flow-blocking plate. Through the coordinated operation of a ring array drive assembly, a conical-surface adapted regulating valve, and a reset assembly, the flow area can be linearly adjusted according to the small pressure difference between the inside and outside of the casing. This not only balances the pressure difference due to the "hollowing effect" during casing installation to prevent casing deformation, but also allows for real-time pump pressure control during cementing to prevent well leakage, adapting to complex conditions such as deep wells and formations with narrow density windows.

Description

Technical Field

[0001] This invention relates to the field of cementing pressure regulation technology, and in particular to a self-locking float collar / float and its cementing pressure adaptive regulation device. Background Technology

[0002] When oil and gas cementing operations are advanced to deep wells, ultra-deep wells, and formations with narrow density windows (where the difference between formation fracture pressure and pore pressure is often ≤2MPa), existing floats and float shoes lack specialized pressure adaptive adjustment devices and rely solely on fixed throttling structures or simple one-way sealing designs. This results in many unavoidable defects in pressure control, seriously affecting operational safety and cementing quality.

[0003] First, it lacks dynamic pressure differential adaptation capability. During the casing running stage, the pressure differential inside and outside the casing changes dynamically with the well depth. Existing devices rely solely on flow channels with fixed orifice diameters to balance the pressure, and cannot adjust the flow area according to the pressure differential. This can lead to either excessive flow resistance causing casing deformation or excessive flow causing annular drilling fluid cross-flow. During cementing, the pump injection pressure fluctuates frequently, and the lack of an adaptive adjustment mechanism makes it impossible to match the pressure changes in real time. This can easily lead to a sudden pressure surge that exceeds the formation fracture pressure and causes well leakage, or insufficient pressure release that results in incomplete cement slurry displacement.

[0004] Secondly, the control of minute pressure differentials fails. Narrow density window formations require extremely high pressure accuracy, but existing devices lack fine adjustment structures and can only achieve coarse "on / off" control, failing to accurately match minute pressure differential changes. This often leads to formation fluid intrusion or cement slurry backflow due to control deviations, damaging the cementation quality. Furthermore, there is no immediate response mechanism; a large pressure differential needs to accumulate to drive the components. In deep wells, the rate of pressure differential change is rapid, and the safety threshold may be exceeded during the lag period, easily causing accidents such as casing damage and well leakage. Summary of the Invention

[0005] Given the existing technical problems of lacking an adaptive pressure adjustment device, the float collar and float shoe cannot cope with dynamic pressure difference, resulting in insufficient control accuracy, lag response, and easy occurrence of well leakage and casing deformation, a self-locking float collar and float shoe cementing pressure adaptive adjustment device is proposed.

[0006] Its purpose is to achieve dynamic and precise adjustment of differential pressure, respond instantly to minute changes in differential pressure, enhance the backflow prevention function, adapt to complex well conditions, and improve cementing safety and quality.

[0007] The technical solution of the present invention is a self-locking float shoe cementing pressure adaptive adjustment device, including a float shoe guide cap, a pipe body disposed at the bottom of the float shoe guide cap, a flower hoop disposed inside the pipe body, a one-way valve group disposed inside the flower hoop, a flow baffle plate disposed on one side of the one-way valve group, a flow groove being opened in the flow baffle plate, one side of the one-way valve group abutting against the middle of the flow baffle plate, and also including a pressure adjustment unit disposed inside the flow baffle plate; The pressure regulating unit includes a drive assembly arranged in a ring array around the flow baffle, a reset assembly arranged on the drive assembly, and a regulating valve arranged in the middle of several drive assemblies. The drive assembly is used to drive the regulating valve to move under the action of the internal and external pressure difference of the baffle plate, thereby adjusting the flow area; the reset assembly is used to reset the drive assembly and the regulating valve, and the regulating valve is used to adjust the overlapping area at the valve port of the baffle plate, thereby changing the flow area and realizing pressure regulation. The drive assembly includes a sliding hole penetrating the baffle plate, the flower hoop, and the pipe body; a piston rod disposed in the sliding hole; a drive rod disposed at the bottom of the piston rod; a movable groove opened on the side of the sliding hole; one end of the drive rod movably connected in the movable groove; a limiting rod disposed at one end of the drive rod; and a limiting groove annularly opened on the side wall of the regulating valve; the limiting rod is slidably connected within the limiting groove.

[0008] Furthermore, the piston rod has concave ends, and the sliding hole has expansions on both sides to match the piston rod ends.

[0009] Furthermore, the flow channel has a continuously tapered shape with a decreasing diameter from top to bottom.

[0010] Furthermore, the regulating valve has a conical end away from the one-way valve assembly, a circular end, and a conical surface on the side closest to the one-way valve assembly that is parallel to the surface of the flow channel.

[0011] Furthermore, the reset assembly includes a reset groove formed on the hoop, a reset plate disposed in the middle of the reset groove, reset springs symmetrically disposed on both sides of the reset plate, and the middle part of the reset plate is fixedly connected to the piston rod.

[0012] Furthermore, the drive rod is L-shaped. In the initial state, one end of the drive rod is located on one side of the middle of the movable groove, and the limiting rod is located on one side of the middle of the limiting groove.

[0013] Furthermore, in the initial state, the regulating valve extends and fits into the interior of the one-way valve assembly on the side closest to the one-way valve assembly.

[0014] Another objective of this invention is to provide a self-locking float hoop float shoe, which aims to solve the problems of existing float hoop float shoes causing pipe deformation due to internal and external pressure imbalance during casing installation, high fluid flow resistance during cementing, and insufficient reliability of backflow prevention sealing. By simplifying the structure, it achieves rapid pressure balance, efficient fluid flow, and unidirectional stable locking, adapting to complex cementing conditions and ensuring the safety of casing installation and cementing quality.

[0015] To achieve the above objectives, the present invention provides the following technical solution: a self-locking floating hoop and floating shoe, comprising: The floating shoe guide cap includes a tube body located at the bottom of the floating shoe guide cap, a flower hoop located inside the tube body, a one-way valve assembly located inside the flower hoop, a flow baffle plate located on one side of the one-way valve assembly, one side of the one-way valve assembly abutting against the middle of the flow baffle plate, and a connecting hole annularly opened on the side wall of the tube body.

[0016] Furthermore, the one-way valve assembly includes a valve stem disposed in the middle of the ferrule, a valve plate disposed on one side of the valve stem, and a one-way spring disposed on one side of the valve plate. The one-way spring abuts against one side of the ferrule, and the ferrule is perforated around its perimeter, which is connected to the flow groove and the outside of the pipe body respectively.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. It has precise pressure adaptive adjustment capability, which solves the defect of existing technology that lacks dynamic pressure regulation function. Through the coordinated use of ring array drive components, conical surface adapted regulating valves and reset components, it can linearly adjust the flow area according to the small pressure difference inside and outside the casing. It can balance the pressure difference of "hollowing effect" during the casing running stage to prevent casing deformation, and can also adjust the pump pressure in real time during cementing to prevent well leakage. It is suitable for complex working conditions such as deep wells and formations with narrow density windows.

[0018] 2. Effectively avoids the risk of jamming of adjustment components and ensures the reliability of operation. The design of double sealing ring of sliding hole and spiral guide groove extending to fit into the one-way valve group, and limit groove through groove structure, combined with fine cement slurry adaptation scheme, can prevent cement solid particles from entering the movement gap; the design of closed cavity of reset component and spring protective sleeve avoids spring corrosion jamming, solves the problem of easy failure of existing technology components, and extends the service life of tool.

[0019] 3. Enhanced backflow prevention and full-stage adaptability, improving cementing quality. The one-way valve group and the hollowed-out structure of the hoop work together to facilitate efficient fluid flow during cementing and form a rigid seal under reverse conditions. The pipe body connecting hole assists in differential pressure balance and sealing lock, realizing full-stage functional adaptability during casing installation, cementing, and waiting for curing. This solves the defects of insufficient redundancy and single function in the existing backflow prevention technology and reduces the risk of formation fluid intrusion. Attached Figure Description

[0020] Figure 1This is a three-dimensional structural diagram of the floating hoop and floating shoe of the present invention; Figure 2 This is a schematic diagram of the overall internal cross-sectional structure of the present invention; Figure 3 This is a schematic diagram of the overall front cross-sectional structure of the floating hoop and floating shoe of the present invention; Figure 4 For the present invention Figure 3 Enlarged structural diagram at point A in the middle; Figure 5 This is an exploded structural diagram of the internal structure of the floating hoop and floating shoe of the present invention; Figure 6 This is a three-dimensional structural schematic diagram of the pressure regulating unit of the present invention; Figure 7 This is a schematic diagram of the front half-section structure of the floating hoop and floating shoe of the present invention; Figure 8 This is a three-dimensional structural diagram of the regulating valve of the present invention.

[0021] In the picture: 1. Floating shoe guide cap; 11. Pipe body; 12. Flower hoop; 13. One-way valve assembly; 131. Valve stem; 132. Valve plate; 133. One-way spring; 14. Flow baffle; 15. Flow groove; 16. Regulating valve; 2. Drive assembly; 21. Sliding hole; 22. Piston rod; 23. Drive rod; 24. Movable groove; 25. Limiting rod; 26. Limiting groove; 3. Reset assembly; 31. Reset groove; 32. Reset plate; 33. Reset spring; 4. Connecting hole. Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] Example 1, referring to Figures 1-8This invention provides a self-locking float shoe cementing pressure adaptive adjustment device, comprising a float shoe guide cap 1, a pipe body 11 fixedly connected to the bottom of the float shoe guide cap 1, a hoop 12 installed inside the pipe body 11, a one-way valve assembly 13 installed inside the hoop 12 for one-way communication, a flow-blocking plate 14 sealingly abutting one side of the one-way valve assembly 13, a flow groove 15 formed inside the flow-blocking plate 14, one side of the one-way valve assembly 13 abutting the middle of the flow-blocking plate 14, and a pressure adjustment unit disposed within the flow-blocking plate 14; the pressure adjustment unit includes a drive assembly 2 arranged in a ring array around the flow-blocking plate 14, a reset assembly 3 disposed on the drive assembly 2, and a regulating valve 16 movably connected to the middle of several drive assemblies 2; the drive assembly 2 is used to drive the regulating valve under the action of the internal and external pressure difference of the flow-blocking plate 14. The flow area is adjusted by moving the valve 16; the reset assembly 3 is used to reset the drive assembly 2 and the regulating valve 16. The regulating valve 16 is used to adjust the overlapping area at the valve port of the baffle plate 14, thereby changing the flow area and realizing pressure regulation; the drive assembly 2 includes a sliding hole 21 penetrating the baffle plate 14, the hoop 12 and the pipe body 11, a piston rod 22 that is slidably connected in the sliding hole 21, a drive rod 23 that is fixedly connected to the bottom of the piston rod 22, a movable groove 24 opened on the side of the sliding hole 21, one end of the drive rod 23 that is movably connected in the movable groove 24, a limiting rod 25 that is fixedly connected to one end of the drive rod 23, and a limiting groove 26 that is circumferentially opened on the side wall of the regulating valve 16. The limiting groove 26 also has through grooves on both sides penetrating the regulating valve 16 to avoid cement accumulation. The cement is finely ground cement slurry, which can be achieved by grinding and modification with a water-reducing agent. The limiting rod 25 is limited and slidably connected in the limiting groove 26. Two sealing rings (a combination of fluororubber and polytetrafluoroethylene) can be installed inside the sliding hole 21, located on the outer side of the concave pressure-bearing surfaces at both ends of the piston rod 22, forming a "double sealing barrier". The sealing ring mounting groove is designed as a "pressure self-sealing structure" (the groove opening faces the fluid side). The greater the cement slurry pressure, the tighter the sealing ring fits against the piston rod 22, and the stronger the blocking effect. Alternatively, an anti-clogging screen can be installed, and a "spiral guide groove" can be opened on the inner wall of the sliding hole 21. The groove direction is consistent with the sliding direction of the piston rod 22. If the cement slurry is close to the gap, it will be guided to the main channel by the spiral groove, avoiding accumulation at the gap inlet. At the same time, a micro pressure relief hole (1 mm in diameter) is opened on the outer side of the sealing ring to balance the pressure inside and outside the sealing cavity, preventing the pressure difference from forcing cement into the gap and avoiding affecting the movement of the reset assembly 3 and the piston rod 22.

[0024] Specifically, during the casing installation stage, when the external pressure of the annulus is greater than the internal pressure of the casing, the piston rod 22 slides inward along the sliding hole 21 under the action of the pressure difference. The piston rod 22 drives the drive rod 23 to move synchronously in the movable groove 24. Through the limiting cooperation between the limiting rod 25 and the limiting groove 26, the regulating valve 16 is driven away from the valve port of the flow baffle 14, reducing the overlapping area between the regulating valve 16 and the valve port of the flow baffle 14, reducing the flow resistance, and allowing the annulus drilling fluid to be quickly replenished into the casing through the flow groove 15, balancing the pressure difference inside and outside the casing, and preventing the casing from deforming due to excessive external extrusion pressure. During the cementing stage, when the internal pressure of the casing increases, the high-pressure cement slurry pushes the piston rod 22 to slide outward, and the limiting rod 25 is in the limiting position. The movement within the groove 26 causes the drive rod 23 to move the regulating valve 16 toward the valve port, increasing the overlapping area to increase flow resistance, reduce cement slurry flow rate, and thus reduce pumping pressure and fluctuation pressure, preventing well leakage caused by pressure exceeding formation fracturing pressure. If the internal pressure continues to rise, the regulating valve 16 can further open the one-way valve group 13 to expand the flow channel and achieve staged pressure relief. When the external pressure of the annulus is large, it will push the one-way valve group 13 to automatically block the valve port of the baffle plate 14, achieving one-way locking and preventing cement slurry backflow. When the pressure difference is balanced during the waiting stage of setting, the reset assembly 3 pushes the piston rod 22, drive rod 23 and regulating valve 16 back to the initial position to ensure the stability of subsequent operations. The drive assembly 2 arranged in a ring array ensures that the regulating valve 16 is subjected to balanced force and moves smoothly. The cooperation between the limit rod 25 and the limit groove 26 ensures the adjustment accuracy. The continuous linear adjustment of the flow area can accurately adapt to different well depths, cement slurry densities and formation pressure fluctuation scenarios. The design of the pressure regulating unit and the one-way valve group 13 not only retains the core function of the float collar and float shoe in preventing backflow, but also solves the problem of pressure regulation lag in traditional tools through mechanical adaptive adjustment. It effectively reduces the risk of well leakage and formation fluid intrusion in complex working conditions such as deep wells and narrow density window formations. At the same time, the overall structure is compact and the components are reliably connected. The sealing cooperation between the sliding hole 21 and the piston rod 22 and the anti-erosion design of the drive assembly 2 extend the service life of the tool in the environment of high temperature and high pressure at the bottom of the well and solid particles scouring, significantly improving the safety, stability and construction efficiency of cementing operations.

[0025] Reference Figures 6-7 The piston rod 22 has concave ends, and the sliding hole 21 has an expanded shape on both sides to match the ends of the piston rod 22.

[0026] Specifically, the concave design at both ends of the piston rod 22 and the expansion design on both sides of the sliding hole 21 form a suitable "pressure action chamber" structure. By increasing the pressure action area, the differential pressure driving efficiency and sensing sensitivity are improved. The concave structure makes the two ends of the piston rod 22 form an annular pressure bearing surface. Combined with the cavity space of the expansion section of the sliding hole 21, the contact area between the mud, annular fluid and piston rod 22 in the casing is significantly increased.

[0027] Reference Figure 4The flow channel 15 has a continuously tapered shape with a narrowing diameter from top to bottom.

[0028] Specifically, the flow channel 15 features a tapered design with a continuously narrowing diameter from top to bottom, which guides the cement slurry to form a stable laminar flow, reduces turbulent impact and fluctuating pressure, and improves displacement efficiency. In conjunction with the regulating valve 16, it achieves linear and fine adjustment of the flow area, adapting to the small pressure difference fluctuations in formations with narrow density windows. It also increases backflow resistance in the reverse direction, assisting the one-way valve to enhance the anti-backflow effect. The angular-free structure disperses erosion, avoids particle deposition, extends the service life of the baffle plate 14, and ensures stable operation under complex working conditions.

[0029] Reference Figures 3-8 The regulating valve 16 is conical at one end away from the check valve assembly 13 and round at the other end. The side of the valve closest to the check valve assembly 13 is conical and parallel to the surface of the flow channel 15.

[0030] Specifically, the conical surface parallel to the flow channel 15, in conjunction with axial movement, forms a linear and continuous flow area adjustment, which can adapt to small pressure difference fluctuations; the conical shape at the far end guides the fluid to flow smoothly, reducing turbulence and fluctuating pressure, and lowering cement flow resistance; the round shape at the near end avoids scraping the one-way valve sealing surface, protecting the backflow prevention function; under reverse working conditions, the conical surface fits to increase backflow resistance, assisting the one-way valve to strengthen the seal; the overall edgeless structure disperses erosion and avoids solid phase particle deposition, ensuring adjustment stability and service life under complex working conditions.

[0031] Example 2, refer to Figures 6-7 This is the second embodiment of the present invention. The difference between this embodiment and the first embodiment is that the reset assembly 3 includes a reset groove 31 opened on the hoop 12, a reset plate 32 slidably connected to the middle of the reset groove 31, reset springs 33 symmetrically abutting against both sides of the reset plate 32, and the middle of the reset plate 32 is fixedly connected to the piston rod 22.

[0032] Specifically, when the internal and external pressures are balanced, the symmetrical reset spring 33 applies a balanced elastic force through the reset plate 32, driving the piston rod 22 and the regulating valve 16 to quickly and automatically reset to the initial position, accurately restoring the reference flow area, reserving adjustment space for subsequent pressure fluctuations, and ensuring the continuity of pressure regulation throughout the cementing process (casing installation, cementing, and waiting for setting). The symmetrical spring design can buffer fluid impact and reduce component wear. Through automatic reset, it ensures the closed-loop stability and operational safety of the device's adaptive pressure regulation.

[0033] Reference Figure 7 The drive rod 23 is L-shaped. In the initial state, one end of the drive rod 23 is located on one side of the middle of the movable groove 24, and the limiting rod 25 is located on one side of the middle of the limiting groove 26.

[0034] Specifically, when one end of the drive rod 23 moves to the side of the movable groove 24 near the regulating valve 16, the limiting rod 25 moves to the side of the limiting groove 26, causing one side of the regulating valve 16 to move out of the valve port of the baffle plate 14. At this time, the overlapping area of ​​the valve port of the baffle plate 14 and the regulating valve 16 is zero, and the flow area is the largest, which can meet the large flow requirements of rapid replenishment of annular fluid and rapid pressure release after internal pressure exceeds the limit during casing grouting, thus avoiding the risk of casing deformation or well leakage.

[0035] Reference Figure 7 In the initial state, the regulating valve 16 extends and fits into the one-way valve assembly 13 on the side closest to it.

[0036] Specifically, this configuration enables automatic adjustment of pressure on both sides. In the initial state, the regulating valve 16 extends into the one-way valve assembly 13 from the side closest to it, allowing the regulating valve 16 to intervene in the one-way valve flow channel in advance. This eliminates the need to wait for the pressure difference to accumulate to a certain level before triggering adjustment, significantly improving pressure response sensitivity. Even minute pressure difference fluctuations of 0.5 MPa can quickly drive the regulating valve 16 to move, achieving instantaneous automatic adjustment of pressure on both sides. This initial intervention arrangement also avoids the risk of sudden pressure changes caused by adjustment lag and does not interfere with the normal operation of the reset assembly 3 and the drive rod 23. While ensuring structural compatibility, it further improves the timeliness and reliability of pressure adjustment under complex well conditions. The remaining structure is the same as in Embodiment 1.

[0037] Based on embodiments 1-2, the working principle of this invention is as follows: During the casing installation stage, when the annular external pressure is greater than the casing internal pressure, the piston rod 22 slides inward along the sliding hole 21. Through the L-shaped drive rod 23, the limiting rod 25, and the limiting groove 26, the regulating valve 16 is moved away from the valve port of the flow-blocking plate 14, reducing the overlap area to zero and maximizing the flow area. The annular drilling fluid is quickly replenished to balance the pressure difference, preventing casing deformation. During the cementing stage, when the casing internal pressure increases, the high pressure pushes the piston rod 22 outward, causing the regulating valve 16 to move towards the valve port, increasing the overlap area and improving the flow resistance, thus reducing the cement slurry flow rate and pumping pressure. If the internal pressure exceeds the limit, the one-way valve group 13 is further opened for staged pressure release to prevent well leakage. In the reverse operation, the annular high pressure drives the one-way valve group 13 to seal the valve port, achieving one-way locking to prevent backflow. During the waiting stage when the pressure difference is balanced, the symmetrical return spring 33 drives the piston rod 22 and the regulating valve 16 to reset via the return plate 32, restoring the reference flow area. In the initial state, the regulating valve 16 extends and fits into the one-way valve group 13, improving the pressure difference response sensitivity. Combined with the linear fit design of the conical flow groove 15 and the regulating valve 16, it ensures precise and stable regulation and adapts to the pressure fluctuation requirements of complex well conditions.

[0038] Example 3, referring to Figures 1-8The third embodiment of the present invention provides a self-locking float hoop float shoe, comprising: a float shoe guide cap 1, a tube body 11 fixedly connected to the bottom of the float shoe guide cap 1, a flower hoop 12 installed inside the tube body 11, a one-way valve assembly 13 installed inside the flower hoop 12, a flow-blocking plate 14 abutting against one side of the one-way valve assembly 13, one side of the one-way valve assembly 13 abutting against the middle of the flow-blocking plate 14, and a connecting hole 4 annularly opened on the side wall of the tube body 11.

[0039] Specifically, during the casing installation stage, the connecting hole 4 on the side wall of the casing 11 can quickly connect the annulus and the inner cavity of the casing 11, balancing the internal and external pressure difference caused by the "hollowing out" during casing installation and preventing the casing 11 from deforming due to external extrusion. During cement injection, the high-pressure cement slurry pushes the one-way valve assembly 13 away from the sealing contact surface in the middle of the baffle plate 14, and flows smoothly through the flow gap between the baffle plate 14 and the one-way valve assembly 13. The connecting hole 4 simultaneously assists in diverting part of the fluid, reducing local flow resistance and improving the cement slurry displacement efficiency. During the waiting stage or when the annulus pressure increases, the one-way valve assembly 13 tightly abuts against the middle of the baffle plate 14 under the action of reverse pressure, forming a reliable seal. At the same time, the connecting hole 4 can further enhance the locking effect of the one-way valve assembly 13 through fluid pressure feedback, preventing cement slurry backflow or formation fluid intrusion.

[0040] Reference Figures 1-8 The one-way valve assembly 13 includes a valve stem 131 slidably connected to the middle of the hoop 12, a valve plate 132 fixedly connected to one side of the valve stem 131, and a one-way spring 133 abutting against one side of the valve plate 132. The one-way spring 133 also abuts against one side of the hoop 12. The hoop 12 has a hollowed-out shape around its perimeter, which is connected to the flow groove 15 and the outer side of the pipe body 11, respectively. The rest of the structure is the same as that of Embodiment 2.

[0041] Specifically, the one-way valve assembly 13 achieves one-way flow through the valve stem 131, valve plate 132, and one-way spring 133. The hollow design of the hoop 12 connects the flow groove 15 with the outside of the pipe body 11: during cement injection, the high pressure pushes the valve plate 132 to open, and the hollow structure helps the fluid flow smoothly and coordinates pressure regulation; in the reverse condition, the spring returns to its original position, and the valve plate 132 tightly seals the flow-blocking plate 14, enhancing the anti-backflow effect. The overall structure is compatible with the pressure regulating unit, improving flow efficiency and sealing reliability, and adapting to complex cementing conditions.

[0042] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A self-locking float shoe cementing pressure adaptive adjustment device, comprising a float shoe guide cap (1), a pipe body (11) disposed at the bottom of the float shoe guide cap (1), a flower hoop (12) disposed inside the pipe body (11), a one-way valve assembly (13) disposed inside the flower hoop (12), a flow baffle (14) disposed on one side of the one-way valve assembly (13), wherein a flow groove (15) is provided in the flow baffle (14), and one side of the one-way valve assembly (13) abuts against the middle of the flow baffle (14), characterized in that, It also includes a pressure regulating unit disposed within the baffle plate (14); The pressure regulating unit includes a drive assembly (2) arranged in a ring array around the flow baffle (14), a reset assembly (3) arranged on the drive assembly (2), and a regulating valve (16) arranged in the middle of a plurality of drive assemblies (2). The drive assembly (2) is used to drive the regulating valve (16) to move under the action of the internal and external pressure difference of the baffle plate (14) and thus adjust the flow area; the reset assembly (3) is used to reset the drive assembly (2) and the regulating valve (16), and the regulating valve (16) is used to adjust the overlapping area at the valve port of the baffle plate (14) and thus change the flow area to achieve pressure regulation; The drive assembly (2) includes a sliding hole (21) penetrating the baffle plate (14), the flower hoop (12) and the pipe body (11), a piston rod (22) disposed in the sliding hole (21), a drive rod (23) disposed at the bottom of the piston rod (22), a movable groove (24) opened on the side of the sliding hole (21), one end of the drive rod (23) being movably connected in the movable groove (24), a limiting rod (25) disposed at one end of the drive rod (23), and a limiting groove (26) circumferentially opened on the side wall of the regulating valve (16), the limiting rod (25) being slidably connected in the limiting groove (26); The piston rod (22) has concave ends, and the sliding hole (21) has expansion on both sides to match the ends of the piston rod (22); The flow channel (15) has a continuously tapered shape from top to bottom; The regulating valve (16) is conical at one end away from the one-way valve group (13), and circular at the other end. Its side near the one-way valve group (13) is conical and parallel to the groove surface of the flow channel (15).

2. The self-locking float shoe cementing pressure adaptive adjustment device according to claim 1, characterized in that: The reset assembly (3) includes a reset groove (31) opened on the flower hoop (12), a reset plate (32) set in the middle of the reset groove (31), reset springs (33) symmetrically arranged on both sides of the reset plate (32), and the middle part of the reset plate (32) is fixedly connected to the piston rod (22).

3. The self-locking float shoe cementing pressure adaptive adjustment device according to claim 1, characterized in that: The drive rod (23) is L-shaped. In the initial state, one end of the drive rod (23) is located on one side of the middle of the movable groove (24), and the limiting rod (25) is located on one side of the middle of the limiting groove (26).

4. The self-locking float shoe cementing pressure adaptive adjustment device according to claim 1, characterized in that: In the initial state, the regulating valve (16) extends and fits into the one-way valve assembly (13) on the side closest to it.

5. A self-locking float collar / float shoe, employing the self-locking float collar / float shoe cementing pressure adaptive adjustment device as described in claim 1, characterized in that, include: The floating shoe guide cap (1), the tube body (11) set at the bottom of the floating shoe guide cap (1), the flower hoop (12) set inside the tube body (11), the one-way valve group (13) set inside the flower hoop (12), the flow baffle (14) set on one side of the one-way valve group (13), one side of the one-way valve group (13) abutting against the middle of the flow baffle (14), and the connecting hole (4) annularly opened on the side wall of the tube body (11).

6. The self-locking floating hoop and floating shoe according to claim 5, characterized in that: The one-way valve assembly (13) includes a valve stem (131) located in the middle of the flower hoop (12), a valve plate (132) located on one side of the valve stem (131), and a one-way spring (133) located on one side of the valve plate (132). The one-way spring (133) abuts against one side of the flower hoop (12). The flower hoop (12) is hollowed out around its perimeter, which is connected to the flow groove (15) and the outside of the pipe body (11) respectively.

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