A floating collar float shoe for cementing construction

Abstract

This invention discloses a float collar and float shoe for cementing operations, belonging to the technical field of cementing tools. It includes a casing, float collars and guide shoes arranged at intervals from top to bottom. The float collar includes a pressure seat, which has a first liquid channel extending through it along the casing axis. A guide groove is formed on the end face of the pressure seat away from the guide shoe. The inner wall of the guide groove is inclined, with its diameter gradually decreasing from the outside to the center and extending inclinedly to the first liquid channel. The rubber plug first contacts the outer, larger diameter area of ​​the guide groove. Under continuous pump pressure and guided by the inclined surface of the guide groove, it gradually moves towards the first liquid channel in the center of the guide groove, achieving alignment between the rubber plug and the pressure seat. This reduces the deflection of the rubber plug during its descent, allowing it to fit with the inclined surface of the guide groove in a relatively stable posture, avoiding problems such as insufficient local fit and uneven sealing gaps caused by rubber plug deflection.

Description

Technical Field

[0001] This invention belongs to the technical field of cementing construction tools, specifically relating to a floating hoop and floating shoe for cementing construction. Background Technology

[0002] In deep well cementing operations, the rubber plug pressure test is a crucial control step for determining the proper placement of cement slurry and ensuring the safety and quality of cementing operations. Although traditional float collars are equipped with rubber plug pressure seats to achieve the functions of rubber plug placement and sealing, establishing pump pressure, and generating pressure signals, this function is difficult to reliably achieve under the complex conditions of deep wells.

[0003] Deep well operations are generally characterized by long wellbore extension distances, and the downward travel distance of the rubber plug from the wellhead to the float collar position is much greater than in conventional shallow wells. During this long downward journey, the rubber body of the plug continuously contacts and rubs against the inner wall of the casing, while simultaneously being eroded by high-temperature drilling fluid and cement slurry. This accelerates the aging and softening of the rubber material. High frictional resistance and high-speed fluid erosion can cause significant wear, chipping, or deformation of the outer edge of the plug. When the plug reaches the float collar pressure seat, its sealing structure is already incomplete, failing to form an effective seal with the pressure seat, easily leading to sealing gaps. At this point, pump pressure cannot be established normally, the pressure signal is not obvious or even absent, and on-site construction personnel cannot accurately determine whether the cement slurry has been properly displaced, posing potential quality risks to the cementing operation.

[0004] Meanwhile, deep well drilling fluids typically contain a large amount of solid impurities such as rock cuttings, fine sand, and clay particles, with significantly higher impurity content and settling rates than in conventional wells. During casing running and cementing fluid circulation, some solid impurities will deposit on the sealing surface of the float collar pressure seat with the fluid movement, gradually forming a dense slag layer. This slag layer is firmly attached and difficult to detach on its own under the scouring of conventional fluid flow. When the rubber plug is seated, the slag layer between the sealing surfaces will prevent effective contact between the rubber plug and the pressure seat, resulting in poor sealing or even failure to seal. Such problems can lead to false pressure or no pressure, causing operators to misjudge the cementing status and easily triggering a series of cementing quality defects such as insufficient cement slurry displacement, annular channeling, and inadequate bottom sealing, affecting the sealing effect at the bottom of the oil layer casing and subsequent production safety. Summary of the Invention

[0005] The purpose of this invention is to provide a floating collar and float shoe for cementing operations. The rubber plug first contacts the outer large-diameter area of ​​the guide groove. Under the continuous pump pressure and the guidance of the inclined surface of the guide groove, it gradually moves towards the first liquid channel in the middle of the guide groove, realizing the centering of the rubber plug and the pressure seat, reducing the deflection of the rubber plug during its descent, and enabling the rubber plug to fit with the inclined surface of the guide groove in a relatively stable posture, avoiding problems such as insufficient local fit and uneven sealing gap caused by the rubber plug deflection.

[0006] To achieve the above objectives, embodiments of the present invention provide a floating hoop and float shoe for cementing operations, comprising: a casing, including floating hoops and guide shoes arranged at intervals from top to bottom, the floating hoop including a pressure seat, the pressure seat having a first liquid channel extending through it along the casing axis, the end face of the pressure seat away from the guide shoe having a guide groove, the inner wall of the guide groove being an inclined surface, the diameter gradually decreasing from the outside to the middle and extending inclinedly to the first liquid channel.

[0007] In one possible implementation, the float hoop also includes a guide seat, which is disposed on the inner wall of the casing and located below the pressure seat. The guide seat and the pressure seat are connected by a support rod, and a liquid passage is formed between the peripheral wall of the pressure seat and the inner wall of the casing.

[0008] In one possible implementation, the guide seat is provided with a liquid collection channel extending through the sleeve along the axial direction. The liquid collection channel is located below the first liquid channel and is connected to the liquid inlet.

[0009] In one possible implementation, the bottom of the impact seat has a lower guide slope, and the upper part of the guide seat has an upper guide slope;

[0010] The upper guide slope and the lower guide slope are parallel to each other and form a second liquid channel that connects the liquid inlet and the liquid collection channel.

[0011] In one possible implementation, the lower part of the guide seat has a sealing surface;

[0012] An elastic seal is also installed inside the sleeve. The elastic seal is located below the guide seat and is used to elastically press upward against the sealing surface to block the liquid collection channel.

[0013] In one possible implementation, the float hoop also includes a flow channel that runs through the pressure seat, support rod, and guide seat to direct liquid to the pressure surface of the resilient seal.

[0014] In one possible implementation, the flow channel has an upper port, which is opened in the guide groove and located on the outer periphery of the first liquid channel, for receiving the liquid flowing down the sleeve.

[0015] In one possible implementation, the flow channel has a lower port, which is opened on the sealing surface of the guide seat and located on the outer periphery of the liquid collection channel.

[0016] In one possible implementation, the flow channel is arranged at an angle, extending at an angle from the upper port to the lower port in a direction away from the center of the guide seat.

[0017] In one possible implementation, the inner diameter of the flow channel from the upper port to the lower port gradually increases.

[0018] The significant technical effect of this invention is that the rubber stopper first contacts the outer large-diameter area of ​​the guide groove. Under the continuous pump pressure and the guidance of the inclined surface of the guide groove, it gradually moves towards the first liquid channel in the middle of the guide groove, realizing the centering of the rubber stopper and the pressure seat, reducing the deflection of the rubber stopper during its descent, and enabling the rubber stopper to fit with the inclined surface of the guide groove in a relatively stable posture, avoiding problems such as insufficient local fit and uneven sealing gap caused by the deflection of the rubber stopper.

[0019] Because the guide groove has an inclined structure that is wider at the top and narrower at the bottom, a transitional space is formed between the inclined wall and the upper edge of the first liquid channel. As the fluid flows through the guide groove, the flow velocity increases slightly due to the gradually narrowing cross-section of the channel. Impurities, however, have a much higher density, greater weight, and stronger inertia than the fluid, making it difficult for them to quickly change their direction of motion and thus unable to effectively follow the high-speed, changing fluid into the narrow first liquid channel. Some impurities will deposit in this transitional space due to inertia and gravity. Simultaneously, the rubber plug remains spaced from the upper end of the first liquid channel, and the sealing surface is mainly located in the upper part of the guide groove, maintaining a distance from the upper end of the first liquid channel. Therefore, impurities will not directly adhere to the sealing surface. Furthermore, the flow of cementing fluid between the first liquid channel and the guide groove can flush out impurities inside the guide groove, reducing their accumulation and effectively ensuring a good seal. After the pressure test is completed, pressure stabilization and well shut-in operations are performed according to the construction design. The cement slurry gradually solidifies within the annulus between the casing and the well wall, completing the sealing operation at the bottom of the oil layer casing. Compared to traditional flat pressure seats, the inclined transition structure of the guide groove forms a transitional accommodating space, which can effectively prevent solid impurities from forming a slag layer on the sealing and bonding surface, reduce the obstruction of impurities on the bonding between the rubber plug and the pressure seat, ensure that the rubber plug can effectively contact the inclined surface when it is seated, achieve stable sealing through the sealing guide groove, reduce the probability of false pressure and no pressure phenomena, help construction personnel to more accurately judge the cement slurry replacement status, and reduce the hidden dangers of cementing quality. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a cross-sectional structural schematic diagram of a cementing hoop float shoe according to one embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the structure of a well cementing construction float hoop float shoe concealing the casing and guide shoe in one embodiment of the present invention.

[0023] In the diagram: 100, sleeve; 200, float hoop; 210, pressure seat; 211, first liquid channel; 212, guide groove; 213, lower guide slope; 220, guide seat; 221, liquid collection channel; 222, upper guide slope; 223, sealing surface; 230, support rod; 240, liquid inlet; 250, second liquid channel; 260, flow channel; 261, upper port; 262, lower port; 300, guide shoe; 400, elastic seal; 410, pressure surface. Detailed Implementation

[0024] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0026] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0027] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0028] In the description of the embodiments of this application, the term "and / or" is merely a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship. In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0029] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0030] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation", "connection", "linking", and "fixing" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components.

[0031] Please see Figures 1-2 This illustration shows a cementing float collar and float shoe according to an embodiment of the present invention, including a casing 100, a float collar 200, and a guide shoe 300. The float collar 200 and the guide shoe 300 are arranged at intervals from top to bottom along the axial direction of the casing 100. The float collar 200 includes a pressure seat 210. In a cementing example operation, the casing 100 is first lowered into the designed depth of the well. The casing 100 equipped with the float collar 200 and the guide shoe 300 is lowered into the deep well. The float collar 200 is located above the guide shoe 300. The pressure seat 210 on the float collar 200 is fixedly installed inside the casing 100. Figure 1 and Figure 2 As shown, the pressure seat 210 is disc-shaped, with a diameter smaller than the inner diameter of the casing 100. A first liquid channel 211 is axially extending through the pressure seat 210 along the casing 100. This channel is used for the flow of drilling fluid and cement slurry during the cementing process. Figure 1 As shown, the guide shoe 300 has an outlet hole for discharging liquid from the first liquid channel 211 into the well.

[0032] After cementing operations are initiated, cement slurry is first injected into the casing 100. Once the cement slurry injection is complete, a rubber plug is deployed from the wellhead. The rubber plug is made of elastic rubber, and its outer diameter is approximately the same as the inner diameter of the casing 100. Under the pressure of the wellhead pump, it moves downwards along the inner wall of the casing 100 with the drilling fluid. During the long-distance descent of the deep well, the rubber body of the plug continuously rubs against the inner wall of the casing 100, and is simultaneously subjected to erosion by the high-temperature drilling fluid and cement slurry, inevitably resulting in wear, chipping, or slight deformation of the outer edge.

[0033] The rubber stopper continues to descend until it reaches the position of the pressing seat 210 of the float hoop 200. The pressing seat 210 is located away from the end face of the guide shoe 300, that is, the upper end face is provided with a guide groove 212. The inner wall of the guide groove 212 is an inclined surface, and the diameter gradually decreases from the outside to the middle. The inclined surface continues to extend to the upper edge of the first liquid channel 211, forming a tapered guide groove 212 structure that is wider at the top and narrower at the bottom. The lower edge of the guide groove 212 coincides with the upper edge of the first liquid channel 211, that is, the diameter of the lower edge of the guide groove 212 is equal to the diameter of the upper edge of the first liquid channel 211. The rubber stopper first contacts the outer large-diameter area of ​​the guide groove 212. Under the continuous pump pressure and the guidance of the inclined surface of the guide groove 212, it gradually moves towards the first liquid channel 211 in the middle of the guide groove 212, realizing the centering of the rubber stopper and the pressing seat 210, reducing the deflection of the rubber stopper during its descent, and enabling the rubber stopper to fit with the inclined surface of the guide groove 212 in a relatively stable posture, avoiding problems such as insufficient local fit and uneven sealing gap caused by the deflection of the rubber stopper.

[0034] Specifically, as the wellhead pump pressure continues to rise, a small amount of fluid between the rubber plug and the inclined surface of the guide groove 212 is gradually squeezed into the first liquid channel 211 and discharged. The pressure above the rubber plug is greater than the pressure inside the guide groove 212 and the flow channel below, forming a pressure difference. This pressure difference generates a clamping force on the rubber plug pointing towards the pressure seat 210, pushing the worn rubber plug to further conform to the inclined surface of the guide groove 212. Even if the rubber plug has a certain degree of wear, the pressure clamping action can make up for the fitting gap, indirectly sealing the first liquid channel 211 by sealing the guide groove 212. During this process, the degree of fit between the rubber plug and the inclined surface gradually increases, the sealing effect of the guide groove 212 is more stable, the blocking effect of the main flow channel inside the casing 100 is more reliable, the pump pressure rise trend is more gradual and obvious, and the formed pressure signal is more stable, avoiding problems such as poor sealing and missing pressure signal caused by rubber plug wear.

[0035] During this process, some of the solid impurities such as rock cuttings and fine sand contained in the deep well drilling fluid will move with the fluid to the pressure seat 210 area. Since the guide groove 212 has an inclined structure that is wider at the top and narrower at the bottom, a transitional containment space is formed on the inclined wall above the upper edge of the first liquid channel 211, that is, a local area of ​​the guide groove 212 near the first liquid channel 211. Specifically, the transitional containment space refers to the space where, as the fluid flows through the guide groove 212, the flow velocity will increase slightly due to the gradual reduction in the channel cross-section. However, the impurities are much denser than the fluid, heavier, and have stronger inertia, making it difficult for them to quickly change their direction of movement. They cannot follow the high-speed turning fluid into the relatively narrow first liquid channel 211. Some impurities will be deposited in a local area of ​​the guide groove 212 near the first liquid channel 211 due to inertia and gravity. Therefore, this local area is called the transitional containment space.

[0036] Meanwhile, the rubber stopper remains spaced from the upper port 261 of the first liquid channel 211, and the sealing surface is mainly located in the upper part of the guide groove 212, maintaining a distance from the upper port 261 of the first liquid channel 211. Therefore, impurities will not directly adhere to the sealing surface. Simultaneously, the flow of cementing fluid between the first liquid channel 211 and the guide groove 212 can flush away impurities inside the guide groove 212, reducing impurity deposition and accumulation, effectively ensuring the sealing effect. After the pressure test is completed, pressure stabilization and well shut-in operations are performed according to the construction design. The cement slurry gradually solidifies within the annulus between the casing 100 and the well wall, completing the sealing operation at the bottom of the oil layer casing 100. Compared to the traditional planar pressure seat 210, the inclined transition structure of the guide groove 212 forms a transitional accommodating space, which can effectively prevent solid impurities from forming a slag layer on the sealing and bonding surface, reduce the obstruction of impurities on the bonding between the rubber plug and the pressure seat 210, and ensure that the rubber plug can effectively contact the inclined surface when it is seated. Stable sealing is achieved through the sealing guide groove 212, reducing the probability of false pressure and no pressure phenomena, helping construction personnel to more accurately judge the cement slurry replacement status, and reducing the hidden dangers of cementing quality.

[0037] Regarding the aforementioned transitional containment space and the working condition where the rubber plug and the upper port 261 of the first liquid channel 211 are kept at a distance, this example provides a reference parameter as follows: the rated pressure of the cementing operation pump is 15MPa~25MPa, the rubber plug is an elastic cementing rubber plug with a Shore hardness of 65A~75A, the axial distance from the upper opening of the guide groove to the upper port of the first liquid channel is 8mm~15mm, and the inclination angle between the guide groove wall and the central axis of the casing is set to 15°~25°. Based on this, the maximum axial deformation of the rubber plug is only 5mm~9mm, which is less than the total effective depth of the guide groove. This example is only a reference example, and the specific parameters can be adjusted according to the actual working conditions. It is not limited here.

[0038] In this example, when the rubber stopper is attached to the inclined surface, the pressure is evenly transmitted to the body of the pressure seat 210 along the inclined surface, avoiding pressure concentration in a local area and reducing the risk of deformation of the pressure seat 210 due to high pressure. At the same time, the guide groove 212 structure does not require additional complex sealing components, simplifying the overall structure of the pressure seat 210 and reducing the probability of component aging and failure under high temperature and high pressure.

[0039] In a further example, the float hoop 200 also includes a guide seat 220, which is fixedly disposed on the inner wall of the sleeve 100 and located below the pressing seat 210. The guide seat 220 and the pressing seat 210 are connected by multiple support rods 230, so that the pressing seat 210 and the guide seat 220 form a relatively stable integral component. A liquid collection channel 221 is opened through the guide seat 220 along the axial direction of the sleeve 100. The liquid collection channel 221 is coaxially arranged directly below the first liquid channel 211. The bottom of the pressure seat 210 has a lower guide slope 213, and the upper part of the guide seat 220 has an upper guide slope 222. The upper guide slope 222 and the lower guide slope 213 are parallel to each other and form a second liquid channel 250 connecting the liquid outlet 240 and the liquid collection channel 221. This allows one stream of fluid to flow downward through the first liquid channel 211 of the pressure seat 210, and another stream of fluid to flow downward through the liquid outlet 240 between the peripheral wall of the pressure seat 210 and the inner wall of the sleeve 100. After the two streams of fluid converge in the space between the pressure seat 210 and the guide seat 220, they enter the liquid collection channel 221 of the guide seat 220 and then flow downward along the liquid collection channel 221, thus achieving orderly flow of fluid.

[0040] Specifically, as the rubber plug continues to descend to the upper surface of the pressure seat 210, under the gradual increase of the wellhead pump pressure, the elastic rubber plug undergoes adaptive deformation. The central area of ​​the rubber plug extends downward along the conical guide groove 212 to fit against the surface, indirectly sealing the first liquid channel 211 through the sealing guide groove 212. Simultaneously, as... Figure 1 and Figure 2 As shown, the pressure-pressing seat 210 is supported by a support rod 230 extending from bottom to top. Therefore, there is no supporting structure around the pressure-pressing seat 210, allowing the outer edges of both sides of the rubber plug to extend and deform synchronously towards the annular liquid inlet 240 without obstruction. The outer edges of both sides of the rubber plug fit against the periphery of the pressure-pressing seat 210 and the inner wall of the casing 100, sealing the liquid inlet 240. The first liquid channel 211 and the liquid inlet 240 are sealed synchronously, and the downward flow channel inside the casing 100 is completely blocked, preventing the fluid from continuing to flow downward. The wellhead pump pressure shows a steady upward trend, forming a clear pressure-pressing signal, which can be used by the construction personnel to determine that the cement slurry has been replaced. After the pressure-pressing is completed and the pump pressure stabilizes, the one-way valve of the float collar 200 is closed to block the fluid backflow, completing the cementing pressure-pressing process. Compared with single-channel sealing, the flow channel sealing effect of dual-area synchronous sealing is more complete, the pump pressure upward trend is more obvious, and the resulting pressure-pressing signal is easier to identify, reducing the probability of misjudgment by the construction personnel.

[0041] It should be noted that deep well drilling fluids contain a significant amount of solid impurities such as rock cuttings and fine sand. Traditional float collars 200 and pressure seats 210 often employ a single central liquid channel structure. The internal flow cross-section of the casing 100 is relatively large. When the fluid descends to the pressure seat 210, it can only pass through this single central channel, causing the flow cross-section to contract. This results in a rapid increase in fluid velocity over a short distance, easily forming localized jets. Simultaneously, there is no flow path between the channel periphery and the inner wall of the casing 100, making it prone to eddies and turbulence. Under turbulent conditions, solid impurities within the fluid undergo irregular rolling motions with the flow field. Some impurities tend to remain and adhere to the upper surface of the pressure seat 210 and the sealing area, gradually forming an accumulation layer that affects the subsequent sealing of the rubber plug. In this example, the flow channel is divided into a first liquid channel 211 and an annular liquid outlet 240. The fluid flows downwards in two paths: a central flow and a circumferential flow, resulting in a more uniform flow field distribution. This avoids the fluid concentrating towards the central area and reduces the vortex region around the channel in traditional structures. Furthermore, the bottom of the pressure seat 210 and the upper part of the guide seat 220 form a smoothly transitioning second liquid channel 250, allowing the two fluid paths to converge smoothly along the parallel slope, reducing the probability of local turbulence. After the flow stabilizes, solid impurities can move orderly along a regular path with the fluid, making them less prone to irregular tumbling due to turbulence. This also reduces the retention and adhesion of impurities in the sealing areas such as the conical guide groove 212 and the liquid outlet 240. This provides a relatively clean mating surface for the subsequent synchronous sealing operation of the central sealing guide groove 212 and the outer sealing liquid outlet 240 of the rubber stopper, reducing the interference of impurities on the adhesion between the rubber stopper and the sealing surface 223 and improving the stability of the sealing process.

[0042] It should be noted that, as Figure 1 and Figure 2 As shown, multiple support rods 230 are arranged circumferentially at intervals and at an angle, providing multiple points of uniform support for the pressure seat 210. During the process of sealing the rubber stopper and pressurizing under high pressure, the support rods 230 can constrain the radial displacement and axial sway of the pressure seat 210, so that the pressure seat 210 always maintains a stable state coaxial with the sleeve 100. This provides a stable mating basis for sealing the first liquid channel 211 in the middle of the rubber stopper and sealing the liquid outlet 240 on the outer edge, reducing the sealing gap caused by structural skewing and improving the reliability of synchronous sealing.

[0043] In a further example, the lower part of the guide seat 220 is machined with a sealing surface 223. An elastic seal 400 is provided inside the sleeve 100 and below the guide seat 220. The elastic seal 400 can generate an upward elastic force to press against the sealing surface 223 of the guide seat 220, thereby achieving one-way sealing of the liquid collection channel 221. The float hoop 200 is also provided with a flow guiding channel 260. The flow guiding channel 260 is a through channel that passes through the pressing seat 210, the support rod 230 and the inside of the guide seat 220 in sequence. Its function is to guide the liquid in the sleeve 100 to the pressing surface 410 of the elastic seal 400 and the sealing surface 223. The flow channel 260 is provided with an upper port 261, which is opened inside the guide groove 212 of the pressure seat 210 and located on the outer periphery of the first liquid channel 211. It is used to receive the liquid flowing downward in the sleeve 100. The flow channel 260 is also provided with a lower port 262, which is opened on the sealing surface 223 of the guide seat 220 and located on the outer periphery of the liquid collection channel 221.

[0044] During the cementing fluid circulation stage, before the rubber plug reaches the pressure seat 210, the drilling fluid and cement slurry in the casing 100 flow downwards. Part of the fluid enters the first liquid channel 211 and the annular liquid inlet 240, and after converging, it enters the liquid collection channel 221. Another part of the fluid enters the upper port 261 of the guide channel 260, flows downwards along the inclined guide channel 260 with a gradually increasing inner diameter, and finally flows out from the lower port 262, directly acting on the pressure surface 410 of the elastic seal 400 and the sealing surface 223.

[0045] Based on the above example, during the cementing fluid circulation stage, the drilling fluid and cement slurry in the casing 100 flow downwards. The fluid is divided into two main paths in the area of ​​the pressure seat 210. One path flows through the first liquid channel 211 and the liquid inlet 240 into the liquid collection channel 221, and flows to the middle area of ​​the pressure surface of the elastic seal 400. The other path enters from the upper port 261 of the guide channel 260 in the guide groove 212, flows along the guide channel 260 that runs through the pressure seat 210, the support rod 230, and the guide seat 220, and finally flows out from the lower port 262. It acts on the outer periphery of the pressure surface 410 of the elastic seal 400, overcomes the elastic pre-tightening force of the elastic seal 400, and separates the elastic seal 400 from the sealing surface 223 of the guide seat 220. In deep wells with high downhole pressure, if the elastic seal 400 is only subjected to the pressure of the liquid flow from the liquid collection channel 221, uneven force and localized off-center loading can easily occur, leading to warping and jamming of the elastic seal 400 during opening and closing, affecting the reliability of the liquid collection channel 221. In this example, the liquid flow from the liquid collection channel 221 acts on the middle of the pressure-bearing surface 410, while the liquid flow from the guide channel 260 acts on the outer periphery of the pressure-bearing surface 410. This makes the hydraulic pressure distribution on the pressure-bearing surface 410 of the elastic seal 400 more uniform, reducing off-center warping and making its opening and closing process smoother. Even under the impact of high-pressure fluid in deep wells, it can still stably achieve separation and reset actions, improving the reliability of the flow channel opening and closing. In addition, the high pressure of the fluid in deep wells means that the outlet of the liquid collection channel 221 acts concentrated on the middle of the pressure-bearing surface 410, easily forming localized high pressure in this area. Long-term high pressure will accelerate the wear and deformation of the elastic seal 400 and the sealing surface 223, shortening the service life of the components. The flow channel 260 directs a portion of the fluid flow to the outer periphery of the pressure-retaining surface 410, dispersing the concentrated hydraulic pressure in the central region and reducing the local pressure peak in the center of the pressure-retaining surface 410, thus ensuring a uniform pressure transition across the entire pressure-retaining surface 410. This optimized pressure distribution reduces plastic deformation and wear of the elastic seal 400 caused by localized high pressure, while also reducing erosion damage to the sealing surface 223, extending the service life of the elastic seal 400 and the sealing surface 223 of the guide seat 220, and adapting to the long-term operational needs of deep wells.

[0046] Meanwhile, deep well drilling fluid contains a large amount of solid impurities such as rock cuttings and fine sand. These impurities easily deposit and accumulate in the pressure-bearing area between the elastic seal 400 and the sealing surface 223, forming a slag layer, which leads to poor sealing and seal failure. The lower port 262 of the flow channel 260 is located on the outer periphery of the pressure-bearing surface 410. During circulation, it continuously outputs fluid flow to the outer periphery. This fluid flow can actively flush the outer periphery and edge areas of the pressure-bearing surface 410, promptly carrying away the small amount of deposited and adhered solid impurities and preventing impurities from accumulating on the sealing mating surface. Compared with the traditional structure that relies solely on the central fluid flow, the outer periphery flushing can cover the slag-accumulating area of ​​the sealing surface 223, keeping the pressure-bearing surface 410 clean, reducing the interference of impurities on the sealing effect, and ensuring the sealing performance of the elastic seal 400.

[0047] It should be noted that when the rubber plug is seated and sealed in a deep well, if the flow channel 260 is closed delayed, continuous fluid pressure supply and the inability of the elastic seal 400 to reset in time can easily occur, leading to a delay in the pressure contact signal and fluid cross-flow. The upper port 261 of the flow channel 260 is located within the guide groove 212 and on the outer periphery of the first liquid channel 211. As the rubber plug extends along the guide groove 212 and indirectly seals the first liquid channel 211, it simultaneously covers and seals the upper port 261 of the flow channel 260, immediately stopping the fluid supply to the outer periphery. This allows for rapid response to pressure changes in the central fluid flow, helping the elastic seal 400 to reset and seal in time, improving the response speed of the pressure contact process, and preventing fluid cross-flow from affecting the clarity of the pressure contact signal.

[0048] In a further example, the flow channel 260 is arranged at an angle, extending from the upper port 261 to the lower port 262, tilting away from the center of the guide seat 220. The flow channel 260 tilts outwards, allowing the fluid flow to spread outwards along the pressure surface 410, reducing the rigid impact on the elastic seal 400. Simultaneously, the inner diameter of the flow channel 260 gradually increases from the upper port 261 to the lower port 262, allowing the fluid velocity to gradually decrease and the flow to become smoother. This reduces the erosion damage to the elastic seal 400 caused by high-speed fluid flow and lowers the risk of solid impurities clogging the channel. It also expands the range of the outlet fluid flow, making the force on the outer periphery of the elastic seal 400 more uniform. Combined with the tilted forward flow structure, this further optimizes the pressure distribution on the sealing surface 223, improving the opening and closing stability and sealing reliability of the elastic seal 400, making it suitable for complex operating conditions in deep wells with high pressure and high solid impurities.

[0049] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. 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 protection of the claims of the present invention.

Claims

1. A floating hoop and float shoe for cementing operations, characterized in that, include: The casing (100) includes float collars (200) and guide shoes (300) arranged at intervals from top to bottom. The float collars (200) include a pressure seat (210). The pressure seat (210) is provided with a first liquid channel (211) that runs vertically through it. The first liquid channel (211) is used for cement slurry or drilling fluid to pass through. The upper end face of the pressure seat (210) is provided with a guide groove (212). The guide groove (212) has a diameter that gradually decreases from top to bottom. It is used to limit the rubber plug to be coaxially located in the casing (100) to form a sealing effect on the first liquid channel (211). The guide shoe (300) has an outlet hole for exporting the liquid in the first liquid channel (211) to the well. A liquid passage (240) is formed between the peripheral wall of the pressing seat (210) and the inner wall of the sleeve (100); The float (200) also includes a guide seat (220), which is connected to the inner wall of the sleeve (100) and located below the pressing seat (210). The guide seat (220) and the pressing seat (210) are connected by a support rod (230). The guide seat (220) is provided with a liquid collection channel (221) that runs vertically through it, and the liquid collection channel (221) communicates with the liquid inlet (240).

2. The floating hoop and float shoe for cementing construction according to claim 1, characterized in that, The bottom of the pressing seat (210) has a lower guide slope (213) that extends downward towards the center, and the upper part of the guide seat (220) has an upper guide slope (222) that extends downward towards the center. A second liquid channel (250) is formed between the upper guide slope (222) and the lower guide slope (213), connecting the liquid inlet (240) and the liquid collection channel (221).

3. The floating hoop and float shoe for cementing construction according to claim 2, characterized in that, The lower end face of the guide seat (220) is a sealing surface (223); The sleeve (100) is also provided with an elastic seal (400), which is located below the guide seat (220) and is used to elastically press the sealing surface (223) upward to block the lower opening of the liquid collection channel (221).

4. A floating hoop and float shoe for cementing operations according to claim 3, characterized in that, The float (200) is also provided with a flow channel (260), which runs through the impact seat (210), the support rod (230) and the guide seat (220) to guide the liquid to the pressure surface (410) of the elastic seal (400).

5. A floating hoop and float shoe for cementing operations according to claim 4, characterized in that, The flow channel (260) has an upper port (261), which is located on the side wall of the guide groove (212) and on the outer periphery of the first liquid channel (211).

6. A floating hoop and float shoe for cementing operations according to claim 5, characterized in that, The flow channel (260) has a lower port (262), which is opened on the sealing surface (223) of the guide seat (220) and located on the outer periphery of the liquid collection channel (221).

7. A floating hoop and float shoe for cementing operations according to claim 6, characterized in that, The flow channel (260) is arranged at an angle, extending at an angle from the upper port (261) to the lower port (262) away from the center of the guide seat (220).

8. A floating hoop and float shoe for cementing operations according to claim 6, characterized in that, From the upper port (261) to the lower port (262), the inner diameter of the flow channel (260) gradually increases.

9. A floating hoop and float shoe for cementing operations according to claim 4, characterized in that, The pressing surface (410) of the elastic seal (400) matches the sealing surface (223) and can simultaneously cover and block the lower opening of the liquid collection channel (221) and the lower opening of several of the flow guiding channels (260) under the action of elastic force.

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