Float collar float shoe for well cementation of deep well

Abstract

The invention relates to the technical field of well cementation engineering tools, and discloses a float collar float shoe for well cementation of a deep well, which comprises a float collar, a sleeve, a float shoe and a guide cap which are in threaded connection in sequence, a first one-way feeding unit is arranged in the float collar, and a second one-way feeding unit with the same structure as the first one-way feeding unit is arranged in the float shoe; the first one-way feeding unit comprises a fixedly-arranged skirt structure, a top sealing plate is a horn-shaped gradually-expanding conical surface, a bottom sealing plate is a horn-shaped gradually-shrinking conical surface, and the top sealing plate and the bottom sealing plate are coaxially fixed in a float collar. And when the back pressure of the shaft bottom is larger than 5 MPa, the reverse sealing assembly triggers the spherical sealing curved surface to be reconstructed, the additional pressing force of the central sealing ball and the edge sealing ball is driven to be increased, and 105 MPa extreme back pressure is tolerated.

Description

Technical Field

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

[0002] Float collars and float shoes are crucial components in oil and gas well cementing operations. They are typically installed at the bottom of the casing string. Their primary function is to allow cement slurry to flow smoothly during grouting and quickly close the channel after grouting to prevent slurry from flowing back into the casing. This ensures the integrity of the cement sheath within the annular space, thereby guaranteeing the long-term stability and safety of the wellbore.

[0003] Traditional float collars and float shoes often utilize a check valve structure, which relies on spring preload or gravity to open and close. Specifically, during the grouting phase, as the slurry pressure exceeds the downhole backpressure, the check valve automatically opens, allowing the slurry to flow smoothly into the annular space. After grouting, when the pumping pressure disappears, the check valve quickly closes under the action of a spring, preventing the slurry from flowing back into the casing. This simple and effective design is widely used in conventional cementing operations.

[0004] While traditional float collars and float shoes meet basic cementing requirements to a certain extent, their limitations are becoming increasingly apparent with increasing exploration depths and the challenges of complex geological conditions. The following are some of the key issues: A single sealing structure leads to insufficient reliability: Most traditional float collars and float shoes rely on a single check valve or ball valve for sealing. Under high differential pressure or in the presence of impurities, this single sealing method is prone to leakage or sticking, compromising sealing effectiveness. Slow sealing response: Due to the lack of an effective synchronization mechanism, existing float collars and float shoes cannot immediately complete the channel closure at the end of grouting. This can cause some cement slurry backflow, affecting cementing quality and potentially hindering subsequent operations. Limited resistance to extreme backpressure: Traditional designs often lack sufficient adaptive adjustment capabilities to withstand abnormally high pressures (e.g., formation backpressure exceeding 5 MPa) at the bottom of the well. In such situations, the sealing surface may be breached by the high pressure, making it difficult to withstand extreme backpressures of up to 105 MPa, posing a safety hazard to downhole operations. A lack of linkage: In current designs, the closure of the central channel, edge channel, and bottom channel is typically performed independently, without an effective linkage system. This means that during actual operation, the channels cannot be closed at the same time, which can easily cause local scouring and further increase the risk of sealing failure.

[0005] In summary, while traditional float collars and shoes can perform their basic tasks under certain conditions, existing technology still has significant room for improvement in addressing more complex geological environments and higher safety standards. To overcome these challenges, a more intelligent and efficient solution is needed to enhance sealing performance, speed response, and enhance adaptability to extreme operating conditions. Summary of the Invention

[0006] The object of the present invention is to provide a floating collar and a floating shoe for deep well cementing, so as to solve the problems raised in the above background technology.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a floating collar and a floating shoe for deep well cementing, comprising: The float collar, casing, float shoe and guide cap are threaded in sequence; A first one-way feeding unit is provided in the float collar, and a second one-way feeding unit having the same structure as the first one-way feeding unit is provided in the float shoe; The first one-way feeding unit includes: Fixed skirt structure: the top sealing plate is a trumpet-shaped gradually expanding cone surface, and the bottom sealing plate is a trumpet-shaped gradually contracting cone surface, and the two are coaxially fixed in the floating hoop; Central sealing assembly: A central ball rod that passes through the bottom sealing plate, with a central sealing ball fixed on its top and corresponding to the central flow channel of the top sealing plate. A central telescopic plate is installed outside the central ball rod, and a central jacket layer is formed between the central ball rod and the central jacket layer that accommodates the first main spring; Edge sealing assembly: a plurality of edge ball rods surrounding the central ball rod, with edge sealing balls fixed on the top of the edge ball rods and corresponding to the edge flow channel of the top sealing plate. An edge telescopic plate is arranged on the outer surface of the edge ball rods, and an edge jacket layer is formed between the edge ball rods to accommodate the second main spring; Reverse sealing assembly: The top of the reverse ball rod assembly is connected to the central telescopic plate and the edge telescopic plate through a connecting rod, and the bottom penetrates the bottom flow channel of the bottom sealing plate and fixes the reverse push ball.

[0008] According to the above technical solution, the reverse club assembly includes: The top of the fixed club is fixed to the connecting rod, and the bottom is fixed to the movable plate; The movable rod is nested and movably sleeved outside the fixed ball rod. The bottom is fixed to push the ball in the reverse direction, and its outer wall forms a concave area with a diameter smaller than that of the bottom flow channel.

[0009] According to the above technical solution, an active cavity is provided at the bottom of the reverse push ball, and a matching limit plate is provided at the bottom of the active cavity which is evenly distributed around the circumference; The bottom of the movable plate is provided with a fitting limit groove corresponding to the fitting limit plate; A lifting cavity is provided in the nested movable rod, a fixed plate is fixedly sleeved on the fixed ball rod, and a reset spring is provided between the fixed plate and the top of the lifting cavity; When the movable plate is lowered to the bottom of the movable cavity, a compensation gap is formed between the two; when the back pressure in the well exceeds the threshold, the movable plate moves up to engage the fitting limit groove and the fitting limit plate to form a continuous sealing surface.

[0010] According to the above technical solution, the central telescopic plate and the edge telescopic plates have the same structure and similar functions. The central telescopic plate includes: A central fixed base fixed to the bottom sealing plate; A lifting sleeve is sleeved on the outside of the central ball rod, and a lifting sliding cavity is provided on the inner wall of the lifting sleeve. The top of the central fixed base extends into the lifting sliding cavity and is fixedly installed with a lifting slide. The auxiliary spring is arranged in the lifting sliding cavity, and its two ends respectively abut against the lifting movable sleeve and the central fixed base.

[0011] According to the above technical solution, the central fixed base of the central telescopic plate extends to form a double straight gradually expanding conical guide portion, which extends to the bottom flow channel entrance, for guiding the cement slurry to flow into the flow channel; The edge fixing base of the edge telescopic plate is a straight cylindrical structure, and its outer wall is flush with the conical surface of the bottom sealing plate to form a continuous guide surface.

[0012] According to the above technical solution, the edges of the central circulation channel, the edge circulation channel and the bottom circulation channel are all polished with R0.5-R1mm rounded corners; The inner walls of the central circulation channel, the edge circulation channel and the bottom circulation channel are all covered with a 200-300 μm tungsten carbide wear-resistant layer; The outer surfaces of the top sealing plate and the bottom sealing plate are both covered with a 150-200 μm tungsten carbide wear-resistant layer.

[0013] According to the above technical solution, a first spherical sealing groove is correspondingly provided at one end of the central circulation channel that contacts the central sealing ball, and a first silicon carbide sealing ring is embedded in the edge of the first spherical sealing groove; A second spherical sealing groove is correspondingly provided at one end of the edge circulation channel that contacts the edge sealing ball, and a second silicon carbide sealing ring is embedded in the edge of the second spherical sealing groove; A third spherical sealing groove is correspondingly provided at one end of the bottom circulation channel that contacts the reverse push ball, and a third silicon carbide sealing ring is embedded in the edge of the third spherical sealing groove.

[0014] According to the above technical solution, the central circulation channel is located in the central plane area of ​​the top sealing plate; The edge flow channels are located in the conical surface area of ​​the top sealing plate and are evenly distributed along the circumference of the conical surface; The bottom flow channel is located in the transition area between the conical surface and the plane of the bottom sealing plate, and is ≤10mm away from the plane boundary; A first honeycomb rectifying grid is provided above the plane area of ​​the top sealing plate; A second honeycomb rectifying grid is arranged in the conical surface area of ​​the top sealing plate.

[0015] According to the above technical solution, the first honeycomb rectifying grid is embedded in the inlet section of the central flow channel in a layered nested manner, comprising a honeycomb rectifying layer and a spiral guide layer from top to bottom; The second honeycomb rectifying grid is embedded in the edge flow channel entrance through a conical surface fitting structure, and a memory alloy heat compensation ring is arranged between the two; The embedding depth of the first honeycomb rectifying grid and the second honeycomb rectifying grid does not exceed 1 / 3 of the total length of the corresponding channel.

[0016] According to the above technical solution, the outer walls of the central sealing ball, edge sealing ball and reverse push ball are all covered with double-layer sealing sleeves: The inner layer is a 1.5-2mm hydrogenated nitrile rubber layer; The outer layer is a 0.5-1mm compressible expanded graphite layer.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) Multi-stage linkage to improve sealing performance: Triple sealing coordination: The central sealing ball, edge sealing ball, and reverse push ball are linked by a mechanical connecting rod. When grouting is completed, the three channels are synchronously locked within 0.5 seconds to prevent cement slurry backflow; Back pressure adaptive enhancement: When the bottom hole back pressure is greater than 5MPa, the reverse sealing component triggers the reconstruction of the spherical sealing surface, driving the central sealing ball and edge sealing ball to increase the additional pressing force, and can withstand an extreme back pressure of 105MPa.

[0018] (2) Improved adaptability to extreme working conditions: High-pressure sealing stability: The line sealing design of the central sealing ball and silicon carbide sealing ring is adopted, combined with the pre-load of the first main spring and the linkage pressurization mechanism of the connecting rod, which can still maintain a contact pressure of 126MPa under reverse pressure (105MPa) to achieve zero leakage sealing; High temperature environment tolerance: The memory alloy thermal compensation ring expands 0.15mm at a high temperature of 150℃, accurately compensating for the thermal deformation gap to avoid sealing failure caused by thermal stress. The expanded graphite layer expands at high temperature to fill microscopic defects and maintain the integrity of the seal; Corrosion and abrasion protection: The inner wall of all flow channels and the outer surface of the sealing plate are covered with a 200-300μm tungsten carbide wear-resistant layer with a hardness of nearly 9 Mohs. The wear resistance is 3 times higher than that of traditional hard chrome plating. The chemical inertness of the tungsten carbide coating effectively resists 、 It can resist corrosion from other corrosive media and extend the life of the equipment by more than 5 times.

[0019] (3) Fluid control optimization: The first honeycomb rectifier grid (flat area) eliminates inlet turbulence through the honeycomb rectifier layer and the spiral guide layer, reducing local resistance loss. The second honeycomb rectifier grid (conical area) corrects the fluid direction through the conical surface fitting structure, reduces vortex and backflow, and improves injection efficiency by 25%. The R0.5-R1mm rounded polishing of the channel edge further reduces fluid friction resistance and ensures uniform distribution of cement slurry.

[0020] (4) Sealing system redundancy and long life design: Multiple sealing topology: Metal-silicon carbide-metal triple seal: The central sealing ball and the silicon carbide ring form a rigid line seal, the hydrogenated nitrile rubber layer provides elastic buffer, the expanded graphite layer fills the micro defects, and single point failure does not affect the overall sealing performance. The auxiliary spring assists the seal and can still maintain the sealing pressure when the main spring fails, improving safety by 90%; Fatigue resistance and long cycle operation: The lifting sleeve of the central telescopic plate provides elastic buffering through the auxiliary spring, and the theoretical life is ≥ Operation cycles, memory alloy material can withstand It can withstand multiple thermal cycles without failure and is suitable for frequent start-stop conditions in deep wells.

[0021] (5) Improved engineering life and reliability: The central telescopic plate and the edge telescopic plate fully protect the first and second main springs. The tool can be used 62 times (conventional tools ≤ 23 times). The first and second honeycomb rectifier grids form a filtration system to protect the sealing components from wear. The smooth surface of the tungsten carbide coating (Ra ≤ 0.8 μm) combined with the fluid pulsation effect can automatically remove attached particles and reduce the risk of clogging.

[0022] (6) Optimization of maintenance costs and economic benefits: Reduce the frequency of downtime maintenance: The tungsten carbide wear-resistant layer extends the life of the equipment to 2-3 years in harsh environments such as mines and oil fields (traditional equipment requires monthly maintenance), saving more than 2 million yuan in annual maintenance costs. The self-cleaning design reduces the need for manual cleaning and improves operation continuity; Improve operational efficiency: The two-stage rectifier grid increases the efficiency of cement slurry injection by 25%, shortens the cementing operation time, extends the life of the sealing component by 70%, reduces the frequency of spare parts replacement, and reduces operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 is a first perspective schematic diagram of the present invention; Figure 2 is a second perspective schematic diagram of the present invention; Figure 3 It is an exploded schematic diagram of the present invention; Figure 4 is a first partial perspective schematic diagram of the present invention; Figure 5 is a second partial perspective schematic diagram of the present invention; Figure 6 is a third partial perspective schematic diagram of the present invention; Figure 7 is a fourth partial perspective schematic diagram of the present invention; Figure 8 is a fifth partial perspective schematic diagram of the present invention; Figure 9 is a sixth partial perspective schematic diagram of the present invention; Figure 10 is a seventh partial perspective schematic diagram of the present invention; Figure 11 is an eighth partial perspective schematic diagram of the present invention; Figure 12 is a ninth partial perspective schematic diagram of the present invention; Figure 13 is a tenth partial perspective schematic diagram of the present invention; Figure 14 is an eleventh partial perspective schematic diagram of the present invention; Figure 15 is a twelfth partial perspective schematic diagram of the present invention; In the figure: 1-floating hoop, 2-casing, 3-floating shoe, 4-guide cap, 5-first one-way feeding unit, 51-skirt structure, 511-top sealing plate, 5111-central circulation channel, 5112-edge circulation channel, 512-bottom sealing plate, 5121-bottom circulation channel, 52-bottom sealing plate, 521-central ball rod, 522-central sealing ball, 523-central telescopic plate, 5231-central fixed base, 5232-lifting movable sleeve, 5233-lifting slide cavity, 5234-secondary spring, 5235-double linear gradually expanding cone guide part, 5236-lifting slide plate, 524-first main spring, 53-edge sealing assembly, 531-edge ball rod, 532-edge sealing ball, 533-edge telescopic plate, 5331-edge fixed base, 534-second main spring, 54-reverse sealing assembly, 541-connecting rod, 542-reverse push ball, 5421-movable chamber, 543-fixed ball rod, 544-movable plate, 5441-fitting limit groove, 545-nested movable rod, 5451-lifting chamber, 546-concave area, 547-fitting limit plate, 548-fixed plate, 549-return spring, 601-first spherical sealing groove, 602-first silicon carbide sealing ring, 603-second spherical sealing groove, 604-second silicon carbide sealing ring, 605-third spherical sealing groove, 606-third silicon carbide sealing ring, 701-first honeycomb rectifying grid, 702-second honeycomb rectifying grid, 801-hydrogenated nitrile rubber layer, 802-compressible expanded graphite layer, 9-second unidirectional feeding unit. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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 efforts are within the scope of protection of the present invention.

[0025] See also Figure 1-15 The present invention provides a technical solution: a floating collar and a floating shoe for deep well cementing, comprising: The float collar 1, casing 2, float shoe 3 and guide cap 4 are threadedly connected in sequence; A first one-way feeding unit 5 is provided in the float collar 1, and a second one-way feeding unit 9 having the same structure as the first one-way feeding unit 5 is provided in the float shoe 3; The first one-way feeding unit 5 includes: The fixed skirt structure 51 has a top sealing plate 511 with a trumpet-shaped gradually expanding conical surface and a bottom sealing plate 512 with a trumpet-shaped gradually contracting conical surface, and the two are coaxially fixed in the floating hoop 1; Central sealing assembly 52: A central ball rod 521 extends through the bottom sealing plate 512, with a central sealing ball 522 fixed to its top, corresponding to the central flow channel 5111 of the top sealing plate 511. A central telescopic plate 523 is mounted on the outer surface of the central ball rod 521, forming a central jacket layer between the central ball rod 521 to accommodate the first main spring 524. Edge sealing assembly 53: Several edge ball rods 531 surrounding the central ball rod 521, with edge sealing balls 532 fixed on top of the edge ball rods and corresponding to the edge flow channel 5112 of the top sealing plate 511. Edge expansion plates 533 are installed on the outer surface of the edge ball rods 531, forming an edge jacket layer between the edge ball rods 531 to accommodate the second main spring 534; Reverse sealing assembly 54: The top of the reverse ball rod assembly is connected to the central telescopic plate 523 and the edge telescopic plate 533 through the connecting rod 541, and the bottom passes through the bottom flow channel 5121 of the bottom sealing plate 512 and fixes the reverse push ball 542; Specifically, the reverse club assembly includes: The fixed ball rod 543 is fixed to the connecting rod 541 at the top and the movable plate 544 is fixed at the bottom; The nested movable rod 545 is movably sleeved outside the fixed ball rod 543, with the reverse push ball 542 fixed at the bottom, and its outer wall forms a concave area 546 with a diameter smaller than the bottom flow channel 5121; Specifically, a movable cavity 5421 is formed at the bottom of the reverse push ball 542, and a matching limit plate 547 is evenly distributed around the circumference at the bottom of the movable cavity 5421; The bottom of the movable plate 544 is provided with a fitting limit groove 5441 corresponding to the fitting limit plate 547; The nested movable rod 545 has a lifting cavity 5451 in it, and a fixed plate 548 is fixedly sleeved on the fixed ball rod 543. A return spring 549 is provided between the fixed plate 548 and the top of the lifting cavity 5451. When the movable plate 544 is lowered to the bottom of the movable cavity 5421, a compensation gap is formed between the two. When the back pressure in the well exceeds the threshold, the movable plate 544 moves upward to fit the fitting limit groove 5441 and the fitting limit plate 547, forming a continuous sealing surface. The reverse ball rod assembly is the core sealing and dynamic response mechanism of this device. Its functional design is intended to achieve the following goals: 1. Sealing enhancement under high pressure reverse working conditions: Seal trigger mechanism: When the back pressure in the well exceeds a preset threshold (eg, 5 MPa), the reverse push ball 542 is pushed by the fluid pressure, overcomes the preload of the return spring 549, and moves the movable plate 544 upward.

[0026] Continuous sealing surface formation: When the movable plate 544 moves upward to the limit position, the reverse push ball 542 engages with the fitting limit plate 547 to fill the dynamic sealing gap, forming a complete spherical sealing body (curvature radius R=15mm) and directly closing the entrance of the bottom flow channel 5121.

[0027] Double the sealing strength: Under extreme working conditions (such as 105 MPa back pressure), the contact pressure between the reverse push ball 542 and the third silicon carbide sealing ring 606 can reach 126 MPa, and the microscopic defects are further filled through the plastic flow of the expanded graphite layer 802 to achieve zero leakage.

[0028] 2. Dynamic linkage control of the clamping force of the central / edge sealing components: Mechanical linkage boost mechanism Connecting rod driving principle: The up and down movement of the movable plate 544 is transmitted to the central telescopic plate 523 and the edge telescopic plate 533 through the connecting rod 541, thereby forming a linkage supercharging effect.

[0029] Calculation of additional pressing force (the additional pressing force of the central sealing ball 522 is different from that of the edge sealing ball 532. The central sealing ball 522 is connected by a short lever arm, and the edge sealing balls 532 are connected by a long lever arm, forming an asymmetric lever system. The central circulation channel 5111 bears the main flow and requires priority to strengthen the seal. The flow of the edge circulation channel 5112 is dispersed to multiple balls, and the additional force required for each ball is reduced): Central sealing ball 522: Additional pressing force =1.2×back pressure (for example, when the back pressure is 10MPa, =12MPa).

[0030] Edge sealing ball 532: Additional pressing force =0.8×back pressure( =8MPa).

[0031] Improved sealing stability: Through the linkage pressurization, the contact pressure between the central / edge sealing ball and the corresponding sealing groove is significantly increased, ensuring that there is no slippage or leakage on the sealing surface under high-pressure reverse working conditions.

[0032] Flow control of the concave area 546 Dynamic Alignment Design: During the cement slurry injection stage, the nested movable rod 545 moves downward, and the concave area 546 is precisely aligned with the bottom flow channel 5121 to form a trapezoidal flow cross-section (maximum opening width 2.5 mm) to optimize fluid distribution.

[0033] Reverse shutdown protection: When the reverse push ball 542 moves upward, the concave area 546 is separated from the bottom flow channel 5121, thereby avoiding wear caused by reverse flushing of the fluid.

[0034] 3. Multi-stage sealing topology optimization and failure redundancy design: Limited interlocking structure After the engaging limiting groove 5441 of the movable plate 544 is engaged with the engaging limiting plate 547 , a continuous spherical sealing surface is formed to eliminate the sealing gap.

[0035] Redundant design: Even if a local sealing surface fails due to wear or impurities, the overall sealing surface after fitting can still maintain sealing performance, avoiding system collapse caused by single point failure.

[0036] Compensation function of active cavity 5421 Micro-seepage control: The active cavity 5421 at the bottom of the reverse push ball 542 allows a small amount of fluid to seep out (flow rate <0.5 L / min), thereby avoiding mechanical damage caused by sealing stress concentration.

[0037] Self-cleaning effect: Seepage can carry away foreign particles between the sealing surfaces, reducing the risk of wear in long-term use.

[0038] Specifically, the central telescopic plate 523 and the edge telescopic plate 533 have the same structure and similar functions. The central telescopic plate 523 includes: A central fixed base 5231 fixed to the bottom sealing plate 512; The lifting sleeve 5232 is mounted on the outside of the central ball rod 521, and the inner wall of the lifting sleeve is provided with a lifting sliding cavity 5233. The top of the central fixed base 5231 extends into the lifting sliding cavity 5233 and is fixedly mounted with a lifting slide 5236. The auxiliary spring 5234 is located in the lifting sliding cavity 5233, with its two ends respectively abutting against the lifting movable sleeve 5232 and the central fixed base 5231; The central telescopic plate 523 is the core motion and sealing control component of the device. Its functional design is intended to achieve the following goals: 1. Dynamic sealing and channel control Sealing effect in the initial closed state Main spring preload mechanism: The first main spring 524 applies pre-compression through the central fixed base 5231 of the central telescopic plate 523, pushing the central ball rod 521 to drive the central sealing ball 522 to closely contact the first spherical sealing groove 601 (inlaid with the first silicon carbide sealing ring 602). At this time, the central sealing ball 522 and the first spherical sealing groove 601 form a linear seal (contact bandwidth 0.25 mm), and the sealing pressure is directly transmitted by the spring pre-compression.

[0039] Secondary spring assist mechanism: The auxiliary spring 5234 is in a compressed state and transmits force upward through the sliding cavity 5233 of the lifting sleeve 5232, thereby assisting the central sealing ball 522 to maintain sealing when the spring preload fails (such as local wear).

[0040] Channel opening during cement slurry injection Pressure seal break response: When the cement slurry pressure overcomes the preload of the first main spring 524 , the central sealing ball 522 moves downward along the central ball rod 521 and separates from the first spherical sealing groove 601 , forming an annular flow gap (diameter 0.5-1.2 mm) and opening the central circulation channel 5111 .

[0041] Fluid rectification optimization: The double linear gradually expanding conical guide portions 5235 of the central telescopic plate 523 guide the fluid to the inlet of the bottom flow channel 5121 , reducing local resistance loss and avoiding turbulent separation of the fluid.

[0042] 2. Protect the main spring and sealing components from abrasion Isolate mud and corrosive media Telescopic plate isolation design: During the cement slurry injection stage, the central telescopic plate 523 moves downward through the sliding cavity 5233 of the lifting sleeve 5232, isolating the main spring 524 from contact with the slurry and preventing the spring from corrosion.

[0043] Material durability: The central telescopic plate 523 is made of high wear-resistant alloy steel (with a 200-300μm tungsten carbide wear-resistant layer on the surface) to ensure long-term stable operation under high pressure and high temperature environments.

[0044] Sealing component protection Silicon carbide sealing ring 602: High temperature resistance (≤300℃), wear resistance (friction coefficient ≤0.01), and can maintain rigid sealing properties under high pressure.

[0045] 3. Linkage and coordination of the movement of edge / bottom sealing components Connecting rod drive linkage mechanism The downward movement of the central ball rod 521 transmits power to the reverse sealing assembly 54 through the connecting rod 541, pushing the nested movable rod 545 downward, so that the concave area 546 is precisely aligned with the bottom flow channel 5121, forming a trapezoidal flow cross-section (maximum opening width 2.5mm).

[0046] Edge sealing assembly synchronization control The central telescopic plate 523 and the edge telescopic plate 533 are linked by the connecting rod 541 to ensure the synchronous opening and closing of the central sealing ball 522 and the edge sealing ball 532, thereby avoiding sealing imbalance caused by unilateral movement.

[0047] Specifically, the central fixed base 5231 of the central telescopic plate 523 extends to form a double linear gradually expanding conical guide portion 5235, which extends to the entrance of the bottom circulation channel 5121 to guide the cement slurry to flow into the circulation channel; The edge fixing base 5231 of the edge telescopic plate 533 is a straight cylindrical structure, and its outer wall is flush with the conical surface of the bottom sealing plate 512 to form a continuous guide surface; Specifically, the edges of the central circulation channel 5111, the edge circulation channel 5112 and the bottom circulation channel 5121 are polished with R0.5-R1mm fillets; The inner walls of the central circulation channel 5111 , the edge circulation channel 5112 and the bottom circulation channel 5121 are all covered with a 200-300 μm tungsten carbide wear-resistant layer; The outer surfaces of the top sealing plate 511 and the bottom sealing plate 512 are both covered with a 150-200 μm tungsten carbide wear-resistant layer; The R0.5-R1mm rounded corner design can eliminate the sharp angles of the channel edge, reduce turbulence and separation during fluid flow, and the rounded corner transition allows the fluid to pass through the channel more smoothly, avoiding sudden changes in flow rate caused by sudden turns, ensuring that the fluid is evenly distributed to downstream equipment. The rounded corner area reduces the direct impact of hard particles (such as gravel and carbide) on the channel wall, reducing the local wear rate. The hardness of tungsten carbide is close to 9 Mohs, which is much higher than that of metal substrates (such as stainless steel with a hardness of ≤4 Mohs), can effectively resist the abrasive wear of gravel and hard particles. In high-pressure fluid (such as 105MPa) or high-frequency vibration environment, tungsten carbide coating can absorb local stress and prevent the substrate from failing due to fatigue crack expansion. Tungsten carbide forms a dense oxide film in acidic / alkaline environment to prevent corrosive media from penetrating into the substrate and extend the life of the channel. The surface roughness of tungsten carbide coating is low (Ra≤0.8μm), which can reduce the probability of adhesion of impurities (such as mud particles) in the fluid and reduce the risk of clogging. Through the synergistic effect of rounded corner polishing and tungsten carbide coating, the channel and sealing components are in high pressure, high temperature and corrosive media (such as 、 In an environment with high mud pressure, it can run continuously for more than 1,000 hours without failure, reducing the frequency of downtime for maintenance (traditional hard chrome plating requires monthly maintenance, while tungsten carbide coating can extend it to 2-3 years).

[0048] Specifically, a first spherical sealing groove 601 is correspondingly provided at one end of the central circulation channel 5111 that contacts the central sealing ball 522, and a first silicon carbide sealing ring 602 is embedded in the edge of the first spherical sealing groove 601; A second spherical sealing groove 603 is correspondingly provided at one end of the edge circulation channel 5112 in contact with the edge sealing ball 532 , and a second silicon carbide sealing ring 604 is embedded in the edge of the second spherical sealing groove 603 ; A third spherical sealing groove 605 is correspondingly provided at the end of the bottom flow channel 5121 that contacts the reverse push ball 542, and a third silicon carbide sealing ring 606 is embedded on the edge of the third spherical sealing groove 605; Specifically, the central circulation channel 5111 is located in the central planar area of ​​the top sealing plate 511; The edge circulation channels 5112 are located in the conical surface area of ​​the top sealing plate 511 and are evenly distributed along the circumference of the conical surface; The bottom circulation channel 5121 is located in the transition area between the conical surface and the plane of the bottom sealing plate 512, and is ≤10 mm away from the plane boundary; A first honeycomb rectifying grid 701 is provided above the plane area of ​​the top sealing plate 511; A second honeycomb rectifying grid 702 is provided in the conical surface area of ​​the top sealing plate 511; Specifically, the first honeycomb rectifying grid 701 is embedded in the inlet section of the central flow channel 5111 in a layered nested manner, and includes a honeycomb rectifying layer and a spiral guide layer from top to bottom; The second honeycomb rectifying grid 702 is embedded in the entrance of the edge flow channel 5112 through a conical surface fitting structure, and a memory alloy heat compensation ring is provided between the two; The embedding depth of the first honeycomb rectifying grid 701 and the second honeycomb rectifying grid 702 does not exceed 1 / 3 of the total length of the corresponding channel; The first honeycomb rectifying grid 701 and the second honeycomb rectifying grid 702 are a fluid rectifying device composed of a hexagonal honeycomb structure, the core function of which is to optimize the fluid flow characteristics through geometric structure, and has the characteristics of low flow resistance, high stability and strong impact resistance. The first honeycomb rectifying grid 701 is embedded above the plane area of ​​the top sealing plate 511, located at the inlet section of the central circulation channel 5111, and adopts a layered nested structure, including a top-down honeycomb rectifying layer and a spiral guide layer. The honeycomb rectifying layer is composed of hexagonal channels with a pore size of 0.8-1.2mm, which is used for initial fluid rectification and pressure balance. The spiral guide layer guides the fluid to rotate axially through spiral grooves, enhances fluid uniformity, and reduces turbulent separation. The embedding depth does not exceed 1 / 3 of the total length of the central circulation channel 5111 (about 10-15mm) to avoid excessive compression of the flow channel and increase in pressure loss. The second honeycomb rectifying grid 702 is embedded in the top seal plate 511. The conical area of ​​sealing plate 511 connects to the entrance of edge flow channel 5112 and adopts a conical fitting structure. The honeycomb channels match the conical angle (30°-45°) to optimize fluid diversion efficiency. A memory alloy thermal compensation ring (thickness 0.2-0.5mm) is placed between the sealing plate 511 and the first honeycomb rectifying grid 701 to accommodate thermal expansion differences at high temperatures and prevent structural deformation or blockage. The embedding depth does not exceed 1 / 3 of the total length of edge flow channel 5112 (approximately 8-12mm), ensuring uniform fluid distribution without interfering with the movement of the sealing assembly. The dual system reconfiguration of the flow channel can reduce the local resistance coefficient to 0.4 in the turbulent zone (compared to 0.7 for a single grid), reducing the total system pressure drop by 13%. The spiral guide layer of the first honeycomb rectifying grid 701 suppresses thermal eddies, resulting in pressure fluctuations of less than ±0.5MPa at 205°C. The memory alloy ring of the second honeycomb rectifying grid 702 maintains 94% flow balancing efficiency in deep-sea high-temperature wells.

[0049] Specifically, the outer walls of the central sealing ball 522, the edge sealing ball 532 and the reverse push ball 542 are all covered with a double-layer sealing sleeve: The inner layer is a 1.5-2mm hydrogenated nitrile rubber layer 801; The outer layer is a 0.5-1 mm compressible expanded graphite layer 802 .

[0050] The hydrogenated nitrile rubber layer 801 serves as the first line of defense. The hydrogenated nitrile rubber layer provides the necessary elasticity, can effectively absorb and alleviate the mechanical stress caused by factors such as temperature changes and pressure fluctuations, and avoid wear caused by direct contact with hard sealing surfaces. Its good elasticity and resilience allow the sealing sleeve to adapt to sealing surfaces of different shapes and sizes, ensuring a tight fit and reducing the risk of leakage. The expanded graphite layer 802 has excellent high-temperature resistance and can maintain structural stability under extreme temperature conditions without softening or decomposition. It is suitable for sealing needs in high-temperature environments. When the temperature rises, the expanded graphite will expand slightly (expansion rate ≤15%), automatically filling the tiny gaps or defects between the sealing surfaces, enhancing the sealing effect, so that it can maintain sufficient sealing ability in low-temperature environments. Expanded graphite is suitable for most Chemical substances exhibit good inertness and can provide reliable sealing protection in corrosive environments, extending the service life of equipment. By combining hydrogenated nitrile rubber with expanded graphite, a base layer with good elasticity and adaptability and a surface layer with excellent temperature and corrosion resistance are formed. This combination not only improves the overall sealing performance, but also increases the reliability and durability of the system. Even if one layer of the material ages or is damaged due to long-term use or other reasons, the other layer can still maintain a certain sealing effect, reducing the risk of single-point failure and enhancing the safety factor of the entire sealing system. In deep well cementing operations, in working environments with high pressure (≤105MPa), high temperature (≤150℃) and corrosive media, the double-layer sealing sleeve can effectively prevent fluid leakage and ensure operational safety.

[0051] Working Principle: This device is a special tool for deep well cementing operations. It realizes the following core functions through multi-stage sealing and fluid control design: One-way grouting: allows cement slurry to flow from top to bottom in one direction to fill the wellbore annulus; Anti-backflow lock: Automatically seal after grouting is completed to prevent fluid backflow; High-pressure seal: able to withstand high-pressure and high-temperature environments underground; Adaptive adjustment: respond to downhole pressure fluctuations through mechanical linkage structure; Wear-resistant and erosion-resistant: Key components are protected by tungsten carbide / silicon carbide composite to extend service life.

[0052] The specific working process of this device is as follows: Phase 1: Initial shutdown state (device downhole and stationary) Core status: All circulation channels are forcibly closed Working principle: Main spring preload mechanism Central sealing assembly 52: The first main spring 524 applies pre-pressure through the central fixed base 5231 of the central telescopic plate 523, pushing the central ball rod 521 to drive the central sealing ball 522 to closely adhere to the first spherical sealing groove 601 (inlaid with a first silicon carbide sealing ring 602 to form a metal-silicon carbide-metal triple seal. Silicon carbide has the characteristics of high temperature resistance (≤300°C) and wear resistance (friction coefficient ≤0.01), and can withstand the long-term effects of the complex underground environment). At this time, the central sealing ball 522 and the first spherical sealing groove 601 form a linear seal (contact bandwidth 0.25mm), and the sealing pressure is directly transmitted by the pre-pressure of the first main spring 524.

[0053] Edge seal assembly 53: The second main spring 534 applies pre-pressure through the edge fixed base 5331 of the edge telescopic plate 533, pushing the edge ball rod 531 to drive the edge sealing ball 532 to fit tightly against the second spherical sealing groove 603 (inlaid with the second silicon carbide sealing ring 604). The edge sealing ball 532 and the second spherical sealing groove 603 form a circumferentially evenly distributed multi-point seal to ensure that there is no leakage path in the edge area.

[0054] Secondary spring assist mechanism Central telescopic plate 523: The auxiliary spring 5234 is in a compressed state and transmits force upward through the sliding cavity 5233 of the lifting sleeve 5232, thereby assisting the central sealing ball 522 to maintain sealing when the pre-compression of the first main spring 524 fails (such as local wear).

[0055] Edge expansion plate 533: The auxiliary spring 5234 is connected to the conical surface of the bottom sealing plate 512 through the edge fixing base 5331 of the straight tube structure to form a continuous guide surface. At the same time, the elastic force is used to compensate for the slight displacement of the sealing ball 532. The auxiliary edge sealing ball 532 can still maintain the seal when the pre-compression of the second main spring 534 fails (such as local wear).

[0056] Reverse seal lock Reverse seal assembly 54: Nesting activity bar 545: The concave area 546 is located 10 mm above the bottom circulation channel 5121 and has no overlap with the channel, ensuring that the reverse push ball 542 is in a completely closed state.

[0057] Return spring 549: The nested movable rod 545 is pressed to the bottom limit position of the lifting chamber 5451 by the fixing plate 548, and the reverse push ball 542 is pressed against the third spherical sealing groove 605 (embedded with the third silicon carbide sealing ring 606) by the spring force, forming a metal-silicon carbide-metal triple seal.

[0058] Double-layer sealing sleeve: The hydrogenated nitrile rubber layer 801 (1.5-2 mm) and the compressible expanded graphite layer 802 (0.5-1 mm) covering the outer wall of the reverse push ball 542 provide elastic buffering in a stationary state to avoid initial wear caused by direct contact with the hard sealing surface.

[0059] Phase 2: Cement slurry injection (dynamic opening process) Core status: Three channels are opened in stages Working principle: Pressure breaking stage (critical pressure > 4MPa) Central channel open: The cement slurry pressure overcomes the preload of the first main spring 524 (the design value of this application is 3.5 MPa), and the central sealing ball 522 moves downward along the central ball rod 521 and separates from the first spherical sealing groove 601 to form an annular flow gap (diameter 0.5-1.2 mm).

[0060] Central telescopic plate 523: The lifting sleeve 5232 moves downward under the pressure of the cement slurry, isolating the first main spring 524 from contact with the slurry and preventing corrosion of the first main spring 524. The double-linear gradually expanding conical guide portion 5235 guides the fluid to the entrance of the bottom circulation channel 5121, reducing local resistance loss by 37%.

[0061] Edge channel open: The second main spring 534 is overcome by the pressure of the cement slurry, and the edge sealing ball 532 moves downward along the edge ball rod 531 and separates from the second spherical sealing groove 603 to form circumferentially uniform flow gaps (set to 5 groups in this application, with a flow gap spacing of 72° in each group).

[0062] Edge expansion plate 533: The edge fixing base 5331 of the straight-cylinder structure is flush with the conical surface of the bottom sealing plate 512 to form a continuous flow-guiding surface to avoid turbulent separation of the fluid.

[0063] Linked opening of the bottom channel Connecting rod drive: The downward movement of the central ball rod 521 and the edge ball rod 531 transmits power to the reverse sealing assembly 54 through the connecting rod 541, and the fixed ball rod 543 pushes the nested movable rod 545 to move downward. The concave area 546 is precisely aligned with the bottom flow channel 5121 to form a trapezoidal flow cross-section (maximum opening width 2.5mm).

[0064] Flow optimization control: First honeycomb grid 701 (embedded in the entrance section of the central circulation channel 5111): Through the layered and nested honeycomb rectifying layer and spiral guide layer, the central fluid is rectified into laminar flow to reduce energy loss.

[0065] Second honeycomb grid 702 (embedded in the entrance of edge flow channel 5112): The memory alloy heat compensation ring is used to offset the thermal expansion and contraction caused by temperature changes, eliminating the flow separation phenomenon in the conical area.

[0066] Phase 3: End of grouting (intelligent reset seal) Core status: Triple seals closing step by step Working principle: Main spring dominant reset Central sealing assembly 52: When the pump pressure drops to less than 2 MPa, the first main spring 524 releases the pre-compression, pushing the central sealing ball 522 upward to reset, and the sealing contact pressure rises to 5 MPa within 0.5 s.

[0067] Double-layer sealing sleeve 801 / 802: The expanded graphite layer 802 expands slightly (expansion rate ≤ 15%) during the resetting process of the sealing ball, filling microscopic defects and forming a plastic seal.

[0068] Edge seal assembly 53: The second main spring 534 synchronously pushes the edge sealing ball 532 to press the second spherical sealing groove 603 , and the reset time is less than 1.2 s (avoiding the backflow time window).

[0069] Reverse channel double locking Connecting rod linkage: The connecting rod 541 moves upward, driving the nested movable rod 545 to move upward, and the concave area 546 is separated from the bottom flow channel 5121.

[0070] Return spring 549: The reverse push ball 542 is pushed to compress the third silicon carbide sealing ring 606 to form a metal-silicon carbide-metal triple seal.

[0071] Seal topology optimization Spherical surface-sealing ring contact: The contact width between the central sealing ball 522 and the first spherical sealing groove 601 is 0.25 mm, and the contact width between the edge sealing ball 532 and the second spherical sealing groove 603 is 0.15 mm.

[0072] Thermal expansion compensation: The memory alloy thermal compensation ring 539 expands 0.15 mm at 150° C., eliminating sealing failure caused by thermal stress.

[0073] Stage 4: Bottomhole backpressure (overpressure synergistically enhances sealing) Core status: The sealing strength of the entire system is doubled Working principle: Reverse push ball mechanics trigger Backpressure threshold: When the counter pressure is greater than 5 MPa, the movable plate 544 overcomes the preload of the return spring 549 and moves upward.

[0074] Fitting and limited interlocking: When the movable plate 544 is displaced to the limit, the reverse push ball 542, the movable plate 544, and the fitting limit plate 547 are embedded to form a continuous spherical sealing body.

[0075] Active cavity 5421: The active cavity 5421 at the bottom of the reverse push ball 542 allows a slight seepage of fluid (flow rate < 0.5 L / min) to avoid sealing stress concentration.

[0076] Mechanically linked boost Center Seal Reinforcement: The connecting rod 541 moves upward to exert a linkage lifting force through the fixed ball rod 543, and the central sealing ball 522 adds a pressing force to ensure the sealing stability of the central circulation channel 5111.

[0077] Edge Seal Enhancement: The edge sealing ball 532 adds a pressing force to ensure the sealing stability of the edge flow channel 5112.

[0078] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0079] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A floating collar and floating shoe for deep well cementing, characterized by: include: A float collar (1), a casing (2), a float shoe (3) and a guide cap (4) that are threadedly connected in sequence; A first one-way feeding unit (5) is provided in the float collar (1), and a second one-way feeding unit (6) having the same structure as the first one-way feeding unit (5) is provided in the float shoe (3); The first one-way feeding unit (5) comprises: A fixed skirt structure (51): a top sealing plate (511) having a trumpet-shaped gradually expanding conical surface, and a bottom sealing plate (512) having a trumpet-shaped gradually contracting conical surface, both of which are coaxially fixed in the floating hoop (1); Central sealing assembly (52): a central ball rod (521) passing through the bottom sealing plate (512), a central sealing ball (522) fixed on the top thereof and corresponding to the central flow channel (5111) of the top sealing plate (511), a central telescopic plate (523) disposed on the outer surface of the central ball rod (521), and a central jacket layer for accommodating the first main spring (524) is formed between the central ball rod (521); Edge sealing assembly (53): a plurality of edge ball rods (531) surrounding the central ball rod (521), with an edge sealing ball (532) fixed on the top thereof and corresponding to the edge flow channel (5112) of the top sealing plate (511), and an edge telescopic plate (533) disposed outside the edge ball rod (531), forming an edge jacket layer between the edge ball rods (531) for accommodating the second main spring (534); Reverse sealing assembly (54): The top of the reverse ball rod assembly is connected to the central telescopic plate (523) and the edge telescopic plate (533) through a connecting rod (541), and the bottom passes through the bottom flow channel (5121) of the bottom sealing plate (512) and fixes the reverse push ball (542).

2. The floating collar and floating shoe for deep well cementing according to claim 1, characterized in that: The reverse club assembly comprises: A fixed ball rod (543) is fixed to the connecting rod (541) at the top and a movable plate (544) is fixed at the bottom; The movable rod (545) is nested and movably sleeved outside the fixed ball rod (543), and the bottom is fixed with a reverse push ball (542), and its outer wall forms an inner concave area (546) with a diameter smaller than the bottom circulation channel (5121).

3. The floating collar and floating shoe for deep well cementing according to claim 2, characterized in that: The bottom of the reverse push ball (542) is provided with an active cavity (5421), and the bottom of the active cavity (5421) is provided with matching limit plates (547) evenly distributed around the circumference; The bottom of the movable plate (544) is provided with a fitting limit groove (5441) corresponding to the fitting limit plate (547); A lifting chamber (5451) is provided inside the nested movable rod (545), a fixed plate (548) is fixedly sleeved on the fixed ball rod (543), and a return spring (549) is provided between the fixed plate (548) and the top of the lifting chamber (5451); When the movable plate (544) is lowered to the bottom of the movable cavity (5421), a compensation gap is formed between the two; when the back pressure in the well exceeds the threshold, the movable plate (544) moves upward to make the fitting limit groove (5441) fit into the fitting limit plate (547), forming a continuous sealing surface.

4. The floating collar and floating shoe for deep well cementing according to claim 1, characterized in that: The central telescopic plate (523) and the edge telescopic plate (533) have the same structure and similar functions. The central telescopic plate (523) comprises: a central fixed base (5231) fixed to the bottom sealing plate (512); A lifting sleeve (5232) is sleeved on the outside of the central ball rod (521), and a lifting sliding cavity (5233) is provided on the inner wall of the lifting sleeve. The top of the central fixed base (5231) extends into the lifting sliding cavity (5233) and is fixedly mounted with a lifting slide plate (5236); The auxiliary spring (5234) is arranged in the lifting sliding cavity (5233), and its two ends respectively abut against the lifting movable sleeve (5232) and the central fixed base (5231).

5. The floating collar and floating shoe for deep well cementing according to claim 4, characterized in that: The central fixed base (5231) of the central telescopic plate (523) extends to form a double-straight gradually expanding conical guide portion (5235), and the double-straight gradually expanding conical guide portion (5235) extends to the inlet of the bottom circulation channel (5121) to guide the cement slurry to flow into the circulation channel; The edge fixing base (5331) of the edge telescopic plate (533) is a straight cylindrical structure, and its outer wall is flush with the conical surface of the bottom sealing plate (512) to form a continuous guide surface.

6. The floating collar and floating shoe for deep well cementing according to claim 1, characterized in that: The edges of the central circulation channel (5111), the edge circulation channel (5112) and the bottom circulation channel (5121) are all polished with R0.5-R1mm fillets; The inner walls of the central circulation channel (5111), the edge circulation channel (5112) and the bottom circulation channel (5121) are all covered with a 200-300 μm tungsten carbide wear-resistant layer; The outer surfaces of the top sealing plate (511) and the bottom sealing plate (512) are both covered with a 150-200 μm tungsten carbide wear-resistant layer.

7. The floating collar and floating shoe for deep well cementing according to claim 1, characterized in that: A first spherical sealing groove (601) is correspondingly provided at one end of the central circulation channel (5111) that contacts the central sealing ball (522), and a first silicon carbide sealing ring (602) is embedded in the edge of the first spherical sealing groove (601); A second spherical sealing groove (603) is correspondingly provided at one end of the edge circulation channel (5112) that contacts the edge sealing ball (532), and a second silicon carbide sealing ring (604) is embedded in the edge of the second spherical sealing groove (603); A third spherical sealing groove (605) is correspondingly provided at one end of the bottom circulation channel (5121) in contact with the reverse push ball (542), and a third silicon carbide sealing ring (606) is embedded on the edge of the third spherical sealing groove (605).

8. The floating collar and floating shoe for deep well cementing according to claim 1, characterized in that: The central circulation channel (5111) is located in the central plane area of ​​the top sealing plate (511); The edge circulation channels (5112) are located in the conical surface area of ​​the top sealing plate (511) and are evenly distributed along the circumference of the conical surface; The bottom circulation channel (5121) is located in the transition area between the conical surface and the plane of the bottom sealing plate (512), and is ≤10 mm from the plane boundary; A first honeycomb rectifying grid (701) is provided above the plane area of ​​the top sealing plate (511); A second honeycomb-shaped rectifying grid (702) is provided in the conical surface area of ​​the top sealing plate (511).

9. The floating collar and floating shoe for deep well cementing according to claim 8, characterized in that: The first honeycomb rectifying grid (701) is embedded in the inlet section of the central circulation channel (5111) in a layered nested manner, and comprises a honeycomb rectifying layer and a spiral guide layer from top to bottom; The second honeycomb rectifying grid (702) is embedded in the entrance of the edge circulation channel (5112) through a conical surface fitting structure, and a memory alloy thermal compensation ring is provided between the two; The embedding depth of the first honeycomb rectifying grid (701) and the second honeycomb rectifying grid (702) does not exceed 1 / 3 of the total length of the corresponding channel.

10. The floating collar and floating shoe for deep well cementing according to claim 1, characterized in that: The outer walls of the central sealing ball (522), the edge sealing ball (532) and the reverse push ball (542) are all covered with a double-layer sealing sleeve: The inner layer is a 1.5-2 mm hydrogenated nitrile rubber layer (801); The outer layer is a 0.5-1 mm compressible expanded graphite layer (802).

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