A tailpipe rubber plug, a tailpipe rubber plug device with controllable breakdown pressure, and its application method.

Abstract

This invention relates to the field of oilfield tailpipe cementing technology, specifically to a tailpipe rubber plug, a controllable breakdown pressure tailpipe rubber plug device, and its application method. The tailpipe rubber plug includes: a shear pin, an upper body, a lower body, an emergency pin, and an emergency shear sleeve. The upper and lower bodies support the various components of the tailpipe rubber plug and are respectively located at the upper and lower parts of the tailpipe rubber plug. The shear pin connects the tailpipe rubber plug to the central tube. When the pressure applied by the drill pipe rubber plug to the tailpipe rubber plug reaches a first preset pressure value, the shear pin shears off. The emergency shear sleeve is fixed to the center of the cavity of the lower body by the emergency pin. When the pressure applied by the drill pipe rubber plug to the tailpipe rubber plug reaches a second preset pressure value, the emergency pin shears off, and the emergency shear sleeve continues to descend with the drill pipe rubber plug. This invention can activate an emergency breakdown mechanism when the tailpipe rubber plug body encounters obstruction and pressure buildup in the tailpipe, effectively preventing excessive cement slurry from remaining in the tailpipe.

Description

Technical Field

[0001] This invention relates to the field of oilfield tailpipe cementing technology, specifically to a tailpipe rubber plug, a tailpipe rubber plug device with controllable breakdown pressure, and its application method. Background Technology

[0002] With the accelerated pace of oil and gas field exploration and development, the number of tailpipe operations has increased significantly. In this crucial stage of tailpipe cementing, operators often face a series of complex and unique challenges. For example, obstacles may be encountered during tailpipe installation, requiring various methods such as over-lifting, downward pressure, or rotation to attempt passage. These operations often lead to changes in the internal diameter of the tailpipe, or, due to quality issues with the tailpipe plug itself, pressure buildup may occur when the tailpipe encounters obstruction. This can not only result in a large amount of cement residue remaining inside the tailpipe but also affect the sealing quality of the annulus cement, thus posing a potential threat to the safety and production efficiency of the entire oil and gas well.

[0003] Traditional pressure-bearing liner plug designs can typically withstand burst pressures exceeding 10,000 Psi, a value far exceeding the pressure range required for normal cementing operations. While this design improves the pressure-bearing capacity of the liner plug to some extent, it also introduces new problems in emergency situations. When emergency handling of abnormal conditions within the liner is required, traditional liner plugs often fail to puncture due to excessive pressure, making emergency measures difficult to implement. Summary of the Invention

[0004] The purpose of this invention is to provide a tailpipe plug, a tailpipe plug device with controllable breakdown pressure, and a method for applying the same, in order to solve at least one of the above-mentioned technical problems.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] A tailpipe rubber plug for use in conjunction with a drill pipe rubber plug, the tailpipe rubber plug comprising: a shearing pin, an upper body, a lower body, an emergency pin, and an emergency shearing sleeve;

[0007] The upper body and the lower body are used to support the various components of the tailpipe rubber plug, and the upper body and the lower body are respectively disposed on the upper part and the lower part of the tailpipe rubber plug;

[0008] The shearing pin is used to connect the tailpipe plug and the center tube. When the pressure applied by the drill pipe plug to the tailpipe plug reaches the first preset pressure value, the shearing pin is sheared.

[0009] The emergency shear sleeve is fixed to the cavity of the lower body by the emergency pin. When the pressure applied by the drill pipe plug to the tailpipe plug reaches the second preset pressure value, the emergency pin is sheared, and the emergency shear sleeve continues to descend with the drill pipe plug.

[0010] Furthermore, the first preset pressure value is 2000 Psi.

[0011] Furthermore, the second preset pressure value is set according to 80% of the tailpipe's internal pressure resistance.

[0012] Furthermore, the second preset pressure value is 6000 Psi.

[0013] Furthermore, the number of emergency pins is matched with the second preset pressure value.

[0014] Furthermore, the tailpipe plug also includes: a cup, a liner ring, a first sealing ring, a bushing, a second sealing ring, a third sealing ring, a locking body, and a locking ring;

[0015] The inner wall of the upper body is connected to the lower body through the bushing; the outer wall of the bushing is provided with the leather cup, the bottom of the leather cup is provided with the liner ring, the outer wall of the leather cup is provided with the first sealing ring, the emergency shearing sleeve is provided with the second sealing ring between the inner wall of the lower body and the inner wall of the lower body, the outer wall of the lower body is provided with the third sealing ring at the corresponding position of the emergency shearing sleeve, the bottom of the lower body is provided with the locking body, and the outer wall of the locking body is provided with the locking ring.

[0016] A controllable breakdown pressure tailpipe plug device includes: a tailpipe plug and a drill pipe plug as described above.

[0017] Furthermore, the drill pipe rubber plug includes: a drill pipe cup, a sleeve, a sealing head, and a guide head;

[0018] The drill pipe cup is used to clean and scrape the inner wall of the drill pipe. The two drill pipe cups are connected by the sleeve, and the bottommost drill pipe cup is connected to the guide head through the sealing head.

[0019] A method for applying a controllable pressure puncture tailpipe rubber plug device, employing any of the controllable pressure puncture tailpipe rubber plug devices described above, the method comprising the following steps:

[0020] Conduct ground preparation work, including wellbore circulation cleaning, drilling fluid performance adjustment, and tool inspection;

[0021] The tail pipe is lowered into place according to the preset pipe string arrangement and cement grouting operation is carried out;

[0022] The drill pipe plug is delivered, and the tailpipe plug is sheared by pressing it to the first preset pressure value, so that the drill pipe plug and the tailpipe plug are combined into one and continue to descend.

[0023] When the tailpipe plug encounters obstruction and causes pressure buildup, the emergency shear sleeve is sheared by pressing down to the second preset pressure value to establish a flow channel for continued displacement and complete the cementing operation.

[0024] Furthermore, the first preset pressure value is 2000 Psi;

[0025] And / or,

[0026] The second preset pressure value is 6000 Psi.

[0027] The beneficial effects of this invention are as follows:

[0028] This invention improves upon traditional tailpipe plugs by cleverly incorporating an emergency shear sleeve. This sleeve is designed with a breakdown pressure of up to 6000 Psi (or can be flexibly adjusted according to 80% of the tailpipe's internal pressure resistance by changing the number of shear pins), significantly enhancing the emergency handling capability of the tailpipe plug. In emergencies such as internal tailpipe blockage, simply increasing the pressure easily shears the emergency shear sleeve, causing the drill pipe plug and the emergency shear sleeve to descend together, quickly establishing a circulation channel. This invention not only avoids the risk of unfilled work but also ensures the smooth completion of tailpipe cementing operations without disruption, greatly enhancing the operational safety and production efficiency of oil and gas wells. This invention does not sacrifice the smoothness of normal operating procedures, demonstrating high practicality and technological advancement. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the tailpipe rubber plug structure according to one embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of a drill pipe rubber plug structure according to one embodiment of the present invention;

[0031] Figure 3 This is a flowchart illustrating the application method of the controllable breakdown pressure tailpipe plug device according to one embodiment of the present invention.

[0032] Among them, 100, tailpipe rubber plug; 101, shearing pin; 102, upper body; 103, leather cup; 104, liner ring; 105, first sealing ring; 106, lower body; 107, bushing; 108, second sealing ring; 109, third sealing ring; 110, emergency pin; 111, locking body; 112, locking ring; 113, emergency shearing sleeve; 200, drill pipe rubber plug; 201, drill pipe leather cup; 202, sleeve; 203, sealing head; 204, guide head. Detailed Implementation

[0033] The invention will now be discussed with reference to exemplary embodiments. It should be understood that the described embodiments are merely intended to enable those skilled in the art to better understand and thus implement the invention, and are not intended to imply any limitation on the scope of the invention.

[0034] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment".

[0035] Example 1

[0036] Figure 1 This is a schematic diagram of the tailpipe plug structure according to one embodiment of the present invention. Figure 1 As shown, according to one embodiment of the present invention, a tailpipe rubber plug is used in conjunction with a drill pipe rubber plug 200. The tailpipe rubber plug 100 includes: a shearing pin 101, an upper body 102, a lower body 106, an emergency pin 110, and an emergency shearing sleeve 113.

[0037] The upper body 102 and the lower body 106 are used to support the various components of the tailpipe rubber plug 100. The upper body 102 and the lower body 106 are respectively disposed on the upper and lower parts of the tailpipe rubber plug 100.

[0038] The shear pin 101 is used to connect the tailpipe plug 100 and the center tube. When the pressure applied by the drill pipe plug 200 to the tailpipe plug 100 reaches the first preset pressure value, the shear pin 101 is sheared.

[0039] The emergency shear sleeve 113 is fixed to the middle of the cavity of the lower body 106 by the emergency pin 110. When the pressure applied by the drill pipe plug 200 to the tailpipe plug 100 reaches the second preset pressure value, the emergency pin 110 is sheared, and the emergency shear sleeve 113 continues to descend with the drill pipe plug 200.

[0040] In this embodiment, a tailpipe plug 100 is proposed, designed to work in conjunction with the drill pipe plug 200 to efficiently and safely complete key steps in drilling operations. The tailpipe plug 100 includes a shear pin 101, an upper body 102, a lower body 106, an emergency pin 110, and an emergency shear sleeve 113. In terms of overall layout, the upper body 102 is located at the top of the tailpipe plug 100, while the lower body 106 is located at the bottom. Together, they support all components of the tailpipe plug 100, ensuring structural stability and functional integrity.

[0041] The shear pin 101 plays a crucial role as a key component connecting the tailpipe plug 100 and the center tube. During normal operation, as the pressure applied by the drill pipe plug 200 to the tailpipe plug 100 gradually increases until it reaches a preset first pressure value, the shear pin 101 will be sheared as designed, allowing the tailpipe plug 100 to separate from the center tube for the next step of the operation. This design not only improves operational efficiency but also ensures operational safety.

[0042] To address potential abnormal situations, this invention cleverly incorporates an emergency shearing mechanism. The emergency shearing sleeve 113 is fixed to the center of the cavity in the lower body 106 by an emergency pin 110. If the pressure applied by the drill pipe plug 200 to the tailpipe plug 100 increases abnormally, reaching a preset second pressure value, the emergency pin 110 will be sheared. At this point, the emergency shearing sleeve 113 will continue to descend with the drill pipe plug 200, thereby triggering the emergency handling procedure and effectively preventing potential accidents.

[0043] The tailpipe plug 100 is highly flexible, and its composite shear pressure (i.e., the first preset pressure value) and emergency shear pressure (i.e., the second preset pressure value) can be flexibly adjusted according to the actual conditions at the drilling site. This feature allows the tailpipe plug 100 to better adapt to different geological conditions and operational needs, improving the reliability and safety of drilling operations.

[0044] This invention demonstrates broad application potential in critical engineering fields such as tailpipe cementing. Its core technology lies in an innovative process that achieves controllable breakdown pressure. This feature allows for the immediate activation of an emergency breakdown mechanism when the tailpipe plug encounters obstruction within the tailpipe, preventing pressure buildup and smooth passage. This mechanism rapidly establishes a circulation channel, effectively preventing excessive cement slurry retention within the tailpipe, thereby significantly reducing the time required for subsequent cement plug removal and enhancing the sealing effect of the annular cement slurry. This invention not only greatly improves operational efficiency but also significantly enhances operational safety, providing a more reliable and efficient solution for construction in fields such as tailpipe cementing.

[0045] According to one embodiment of the present invention, the first preset pressure value is 2000 Psi;

[0046] Preferably, the second preset pressure value is set according to 80% of the tailpipe's internal pressure resistance.

[0047] Preferably, the number of emergency pins 110 matches the second preset pressure value.

[0048] In this embodiment, the design of the tailpipe plug 100 fully considers pressure control and safety during drilling operations. Specifically, the first preset pressure value is set to 2000 Psi. This value ensures that the tailpipe plug 100 maintains a stable connection when the drill pipe plug 200 is subjected to normal operating pressure. Simultaneously, when the pressure reaches this threshold, the shear pin 101 will precisely shear off, separating the tailpipe plug 100 from the central tube and propelling the drilling process forward. Furthermore, to cope with abnormally high pressure conditions, the second preset pressure value is optimized to 80% of the tailpipe's internal pressure resistance. This design is based on the tailpipe material's safe pressure-bearing capacity, ensuring that even under extreme conditions, excessive pressure can be released safely. In this embodiment, the second preset pressure value is specifically set to 6000 Psi, which corresponds to the number of emergency pins 110. These pins are evenly distributed and fix the emergency shear sleeve 113 in the middle of the cavity of the lower body 106, ensuring that when the second preset pressure value is reached, they can be collectively sheared, allowing the emergency shear sleeve 113 to safely descend with the drill pipe plug 200, establishing an emergency circulation channel, effectively preventing excessive cement slurry retention in the tailpipe, reducing subsequent processing time, and enhancing the cement slurry sealing effect. Furthermore, by adjusting the number of shear pins 101, the shear pressure can be flexibly adjusted to adapt to different well conditions and operational needs, demonstrating the high flexibility and strong adaptability of this invention.

[0049] This invention ensures stable connection and timely separation during normal operation by precisely setting a first preset pressure value of 2000Psi. At the same time, it optimizes the second preset pressure value to 80% of the tailpipe's internal pressure resistance (6000Psi in this example) and matches it with a corresponding number of emergency pins. This effectively copes with abnormal high pressure, establishes an emergency circulation channel, prevents cement slurry retention, reduces subsequent processing time, and enhances the sealing effect. It demonstrates high flexibility and strong adaptability, ensuring the safety and efficiency of drilling operations.

[0050] According to one embodiment of the present invention, the tailpipe plug 100 further includes: a cup 103, a liner ring 104, a first sealing ring 105, a bushing 107, a second sealing ring 108, a third sealing ring 109, a locking body 111, and a locking ring 112.

[0051] The inner wall of the upper body 102 is connected to the lower body 106 through a bushing 107; a leather cup 103 is provided on the outer wall of the bushing 107, a supporting ring 104 is provided at the bottom of the leather cup 103, a first sealing ring 105 is provided on the outer wall of the leather cup 103, a second sealing ring 108 is provided between the emergency shear sleeve 113 and the inner wall of the lower body 106, a third sealing ring 109 is provided on the outer wall of the lower body 106 at the corresponding position of the emergency shear sleeve 113, a locking body 111 is provided at the bottom of the lower body 106, and a locking ring 112 is provided on the outer wall of the locking body 111.

[0052] In this embodiment, the tailpipe plug 100 is mainly supported by an upper body 102 and a lower body 106, which are securely connected by a bushing 107. The upper body 102 not only supports the various key components of the tailpipe plug 100, but is also tightly connected to the lower body 106 through the bushing 107 installed on its inner wall. A cup 103 is cleverly provided on the outer wall of the bushing 107. During drilling, the cup 103 can scrape the inner wall of the casing to ensure that it is smooth and free of impurities. To enhance the pressure-bearing capacity of the cup 103, a support ring 104 is specially configured at its bottom. At the same time, a first sealing ring 105 is installed on the outer wall of the cup 103 to effectively prevent fluid leakage and ensure sealing performance.

[0053] In addition to serving as a load-bearing component, the lower body 106 further enhances the sealing performance of the tailpipe plug 100 through a second sealing ring 108 disposed between its inner wall and the emergency shear sleeve 113, and a third sealing ring 109 disposed on the outer wall of the lower body 106 corresponding to the emergency shear sleeve 113. This multi-seal design ensures that the sealing performance of the tailpipe plug 100 remains unaffected even under extreme operating conditions.

[0054] In addition, the tailpipe plug 100 is equipped with a shearing pin 101 for connecting the tailpipe plug 100 to the center tube. During normal operation, when the pressure applied by the drill pipe plug 200 reaches a first preset pressure value, the shearing pin 101 will precisely shear off, separating the tailpipe plug 100 from the center tube. To cope with possible abnormal situations, this invention designs an emergency shearing mechanism, namely, the emergency shearing sleeve 113 is fixed in the middle of the cavity of the lower body 106 by an emergency pin 110. When the pressure abnormally increases to the preset value, the emergency pin 110 will be sheared off, and the emergency shearing sleeve 113 will continue to descend with the drill pipe plug 200, triggering the emergency handling process.

[0055] A locking body 111 is provided at the bottom of the tailpipe plug 100, and the locking mechanism is engaged through the locking ring 112 on its outer wall. This design not only enhances the stability of the tailpipe plug 100 during operation, but also provides strong protection for its application in complex geological conditions.

[0056] This invention integrates multiple sealing, cleaning, pressure bearing, and emergency shearing functional components to achieve efficient sealing, casing inner wall cleaning, and safe emergency handling under abnormal pressure during drilling operations, significantly improving the stability and safety of the operation.

[0057] Example 2

[0058] Figure 2 This is a schematic diagram of a drill pipe rubber plug structure according to one embodiment of the present invention. Figure 2As shown, according to one embodiment of the present invention, a controllable breakdown pressure tailpipe plug device includes: a tailpipe plug 100 and a drill pipe plug 200 of any type of the present invention.

[0059] Preferably, the drill pipe rubber plug 200 includes: a drill pipe cup 201, a sleeve 202, a sealing head 203, and a guide head 204;

[0060] The drill pipe cup 201 is used to clean and scrape the inner wall of the drill pipe. The two drill pipe cups 201 are connected by a sleeve 202. The bottom drill pipe cup 201 is connected to the guide head 204 through a sealing head 203.

[0061] This embodiment proposes a controllable breakdown pressure tailpipe plug device, which integrates the tailpipe plug 100 and drill pipe plug 200 designs proposed in this invention. The specific structure of the tailpipe plug 100 is described in detail in Embodiment 1. As the core component of the device, the tailpipe plug 100 possesses key functions such as multiple sealing, pressure bearing, and emergency shearing, ensuring the safety and efficiency of drilling operations. The drill pipe plug 200, as a key component that cooperates with the tailpipe plug 100, also has a sophisticated structure and comprehensive functions. The drill pipe plug 200 consists of a drill pipe cup 201, a sleeve 202, a sealing head 203, and a guide head 204. The drill pipe cup 201 is responsible for cleaning and scraping the inner wall of the drill pipe, ensuring its smoothness and freedom from impurities. The two cups are connected and fixed by a robust sleeve 202, ensuring structural stability. The bottommost drill pipe cup 201 is tightly connected to the guide head 204 via a sealing head 203. The sealing head 203 is designed to form a tight seal with the inside of the tailpipe plug 100 to prevent fluid leakage. The guide head 204 plays a crucial role in guiding the drill pipe plug 200 smoothly downwards and accurately inserting it into the tailpipe plug 100. During operation, as the drill pipe plug 200 descends, it passes through each sealing area of ​​the tailpipe plug 100 in sequence. When the pressure reaches the first preset pressure value, the shear pin 101 of the tailpipe plug 100 will precisely shear off, separating it from the central tube. At the same time, the drill pipe plug 200 continues to descend, activating the emergency shearing mechanism inside the tailpipe plug 100 to ensure safe emergency handling even in abnormal situations.

[0062] The controllable puncture pressure tailpipe plug device proposed in this invention achieves multiple functions such as efficient sealing, cleaning of the drill pipe inner wall, and safe emergency handling during drilling operations through precise matching and ingenious design of the tailpipe plug and drill pipe plug, significantly improving the stability and safety of the operation.

[0063] Example 3

[0064] According to one embodiment of the present invention, a controllable breakdown pressure tailpipe cementing device includes a tailpipe plug 100 (e.g., Figure 1 (as shown) and drill pipe rubber plug 200 (as shown) Figure 2 (as shown);

[0065] The tailpipe plug 100 includes: a shearing pin 101, an upper body 102, a cup 103, a liner ring 104, a first sealing ring 105, a lower body 106, a bushing 107, a second sealing ring 108, a third sealing ring 109, an emergency pin 110, a locking body 111, a locking ring 112, and an emergency shearing sleeve 113.

[0066] The shearing pin 101 is used to connect the tailpipe rubber plug 100 and the center tube; the upper body 102 is used to support the components; the cup 103 is used to clean the inner wall of the casing; the liner ring 104 is used to support the cup under pressure; the first sealing ring 105 is used for sealing; the lower body 106 is used to support the components; the bushing 107 is used for cup connection; the second sealing ring 108 is used for sealing; the third sealing ring 109 is used for sealing; the emergency pin 110 is used for emergency shearing; the locking body 111 is used for locking; the locking ring 112 is used for the locking mechanism; and the emergency shearing sleeve 113 is used for emergency shearing with the drill pipe rubber plug.

[0067] The drill pipe rubber plug 200 includes: a drill pipe cup 201, a sleeve 202, a sealing head 203, and a guide head 204;

[0068] The drill pipe cup 201 is used to clean and scrape the inner wall of the drill pipe, the sleeve 202 is used to connect and fix the cup, the sealing head 203 is used to seal with the inside of the tailpipe rubber plug, and the guide head 204 is used to guide the downward insertion of the tailpipe rubber plug 100.

[0069] In this embodiment, after cementing the tailpipe, the drill pipe plug 200 is released and replaced by the emergency shear sleeve 113 of the tailpipe plug 100. After the pressure increases, it is further increased to 2000 Psi, cutting off the shear pin 101. The drill pipe plug 200 and the tailpipe plug 100 then continue to descend as a single unit to clean the casing. If the tailpipe plug 100 cannot descend due to obstruction or other reasons, causing pressure buildup, the emergency pin 110 can be sheared by pressurizing to 6000 Psi (the shear pressure can be adjusted by the number of shear pins 101, generally set to 80% of the tailpipe's internal pressure resistance). The emergency shear sleeve 113 and the drill pipe plug 200 descend, establishing a circulation channel. Replacement continues until the designed safety margin is reached, then replacement is stopped, completing the cementing operation. This avoids a large amount of cement remaining in the tailpipe and poor annular cement sealing quality.

[0070] The controllable puncture pressure tailpipe plug device of the present invention solves the problem of traditional tailpipe plugs failing to establish a circulation channel after encountering obstruction by adding an emergency shear sleeve, thus improving operational safety. The present invention has a simple structure, low cost, and convenient operation, and has the advantages of good application prospects and cost savings in post-processing. It can be widely used in tailpipe cementing and other fields.

[0071] Example 4

[0072] Figure 3 This is a flowchart illustrating the application method of the controllable breakdown pressure tailpipe plug device according to one embodiment of the present invention. Figure 3 As shown, according to one embodiment of the present invention, a method for applying a controllable breakdown pressure tailpipe rubber plug device, using any one of the controllable breakdown pressure tailpipe rubber plug devices of the present invention, includes the following steps:

[0073] Step S102: Perform ground preparation work, including wellbore circulation cleaning, drilling fluid performance adjustment, and tool inspection;

[0074] Step S104: The tail pipe is lowered into place according to the preset pipe string arrangement and cement grouting is performed.

[0075] Step S106: Deploy drill pipe plug 200, and shear tailpipe plug 100 by pressing it to the first preset pressure value, so that drill pipe plug 200 and tailpipe plug 100 are combined into one and continue to descend.

[0076] In step S108, when the tailpipe plug 100 encounters obstruction and causes pressure buildup, the emergency shear sleeve 113 is sheared by pressing down to the second preset pressure value to establish a flow channel for continued displacement and complete the cementing operation.

[0077] Preferably, the first preset pressure value is 2000 Psi;

[0078] And / or,

[0079] The second preset pressure value is 6000Psi.

[0080] This embodiment proposes an application method for a controllable breakdown pressure tailpipe plug device. This method employs an innovative design of tailpipe plug 100 and drill pipe plug 200, achieving efficient and safe tailpipe cementing operations through a series of precisely controlled steps. First, thorough preparation work is carried out on the surface, including wellbore circulation cleaning, drilling fluid performance adjustment, and tool inspection to ensure a clean working environment and normal tool operation. Then, the tailpipe is lowered into position according to a preset pipe string arrangement, and cement slurry injection is performed. For example, a recommended pipe string arrangement is: float shoe + single tailpipe + float collar + single tailpipe + pressure-adhesive collar + tailpipe string + tailpipe hanger + personnel drill pipe + cement head. Next, the drill pipe plug 200 is deployed, and by pressurizing to a first preset pressure value (e.g., 2000 Psi), the tailpipe plug 100 is precisely sheared, causing the drill pipe plug 200 and tailpipe plug 100 to merge and continue descending, cleaning the inner wall of the casing. During operation, if the tailpipe plug 100 cannot descend due to obstruction within the casing, causing pressure buildup, the emergency shear sleeve 113 can be sheared by continuing to pressurize to a second preset pressure value (e.g., 6000 Psi, which can be set by adjusting the number of shear pins based on the principle of the tailpipe's resistance to internal pressure of 80%). This allows the emergency shear sleeve 113 and drill pipe plug 200 to descend, establishing a circulation channel and continuing to displace the plug until the designed safety margin is reached, thus completing the cementing operation. This method not only avoids leaving a large amount of cement inside the tailpipe but also ensures the quality of annular cement sealing, significantly improving the safety and efficiency of tailpipe cementing operations.

[0081] This invention significantly optimizes traditional challenges in tailpipe cementing operations, particularly when the tailpipe plug encounters obstruction. By introducing an emergency shearing mechanism, when the tailpipe plug encounters a hard resistance within the casing and cannot continue descending, a circulation channel can be quickly established, effectively avoiding the risk of large amounts of cement slurry remaining in the tailpipe and thus ensuring the quality of annular cement sealing. This invention not only greatly improves operational safety and reduces potential risks, but also features a simple and rational structure, high reliability, and reduced complexity and cost in post-processing. Through precisely controlled steps and innovative component design, this invention achieves high efficiency and safety in tailpipe cementing operations, bringing significant technological advancements to the oil drilling field.

[0082] Example 5

[0083] According to one embodiment of the present invention, a method for applying a controllable breakdown pressure tailpipe cementing device includes the following steps:

[0084] Step S201, ground preparation work; specifically including:

[0085] ① Ensure adequate circulation to keep the wellbore clear and clean.

[0086] ② Adjust the properties of the drilling fluid to make it suitable for cementing requirements and ensure the safety and stability of the wellbore.

[0087] ③ Check if the tools are complete, check if all accessories are matched, and check if the rubber stopper is intact.

[0088] Step S202, the recommended pipe string arrangement is: float shoe + single tailpipe + float clamp + single tailpipe + pressure clamp + tailpipe string + tailpipe hanger + man-feeding drill rod + cement head.

[0089] Step S203: Lower the tailpipe into place and perform cement grouting.

[0090] Step S204: Insert drill pipe plug 200, replace it with drilling fluid or seawater, pump drill pipe plug 200 to tailpipe plug 100, pressurize to 2000 Psi to shear tailpipe plug 100, drill pipe plug 200 and tailpipe plug 100 combine and continue to descend.

[0091] Step S205: Continue replacement under normal conditions until the pressure joint is completed. If an abnormal situation occurs and the tailpipe rubber plug 100 encounters a group causing pressure buildup, making it impossible to continue replacement, the cementing pump can be used to pressurize to 6000Psi (the shearing pressure can be adjusted by the number of emergency pins 110, generally set according to 80% of the internal pressure resistance of the tailpipe) to shear the emergency shear sleeve 113, establish a flow channel, continue replacement, and complete the cementing operation.

[0092] In this embodiment, the application method of a controllable breakdown pressure tailpipe rubber plug cementing device involves first performing surface preparation work, including wellbore circulation cleaning, drilling fluid performance adjustment, and tool inspection. Then, the tailpipe is lowered into place according to the recommended pipe string arrangement, and cement slurry injection is performed. After the drill pipe rubber plug 200 is deployed, the tailpipe rubber plug 100 is sheared by applying pressure of 2000 Psi, allowing the two to merge and continue descending. If the tailpipe rubber plug 100 encounters obstruction leading to pressure buildup, a cementing pump can be used to apply pressure of 6000 Psi (the shearing pressure can be adjusted according to the number of emergency pins 110) to shear the emergency shear sleeve 113, establishing a flow channel to continue displacement and complete the cementing operation.

[0093] This invention can be widely used in fields such as tailpipe cementing. Its unique controllable puncture pressure process can perform emergency puncture when the tailpipe plug body encounters obstruction in the tailpipe and becomes pressurized and cannot be pushed through, thus establishing a circulation channel and avoiding leaving too much cement slurry in the tailpipe. This reduces the time required to drill the cement plug later and enhances the sealing effect of the annulus cement slurry, greatly improving the safety of the operation.

[0094] The tailpipe plug of this invention features an ingenious design, offering multiple advantages such as compact structure, small size, light weight, ease of processing, low cost, and simple on-site operation. While ensuring the reliable performance of existing tailpipe plugs, this invention incorporates an innovative emergency shearing mechanism, significantly improving operational safety. Through localized optimization and modification of existing tailpipe plugs, this invention can be easily adapted, demonstrating broad application potential, especially suitable for specialized operations such as tailpipe cementing. This invention effectively solves the problem of traditional pressure-bearing tailpipe plugs easily causing pressure buildup and difficulty in establishing circulation channels after obstruction within the tailpipe. The design is both simple and reasonable, ensuring high reliability and significantly reducing subsequent processing costs.

[0095] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

[0096] It should be understood that the sequence number of each step in the invention and embodiments of the present invention does not absolutely imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

Claims

1. A tailpipe rubber plug for use in conjunction with a drill pipe rubber plug (200), characterized in that, The tailpipe plug (100) includes: a shearing pin (101), an upper body (102), a lower body (106), an emergency pin (110), and an emergency shearing sleeve (113). The upper body (102) and the lower body (106) are used to support the various components of the tailpipe plug (100). The upper body (102) and the lower body (106) are respectively disposed on the upper and lower parts of the tailpipe plug (100) body. The shear pin (101) is used to connect the tailpipe plug (100) and the center tube. When the pressure applied by the drill pipe plug (200) to the tailpipe plug (100) reaches the first preset pressure value, the shear pin (101) is cut off. The emergency shear sleeve (113) is fixed to the cavity of the lower body (106) by the emergency pin (110). When the pressure applied by the drill pipe plug (200) to the tailpipe plug (100) reaches the second preset pressure value, the emergency pin (110) is sheared, and the emergency shear sleeve (113) continues to descend with the drill pipe plug (200). The tailpipe plug (100) also includes: a cup (103), a liner ring (104), a first sealing ring (105), a bushing (107), a second sealing ring (108), a third sealing ring (109), a locking body (111), and a locking ring (112). The inner wall of the upper body (102) is connected to the lower body (106) through the bushing (107); the outer wall of the bushing (107) is provided with the leather cup (103), the bottom of the leather cup (103) is provided with the liner ring (104), the outer wall of the leather cup (103) is provided with the first sealing ring (105), the emergency shear sleeve (113) is provided with the second sealing ring (108) between the emergency shear sleeve (113) and the inner wall of the lower body (106), the outer wall of the lower body (106) is provided with the third sealing ring (109) at the corresponding position of the emergency shear sleeve (113), the bottom of the lower body (106) is provided with the locking body (111), and the outer wall of the locking body (111) is provided with the locking ring (112).

2. The tailpipe plug according to claim 1, characterized in that: The first preset pressure value is 2000 Psi.

3. The tailpipe plug according to claim 1, characterized in that: The second preset pressure value is set according to 80% of the tailpipe's internal pressure resistance.

4. The tailpipe plug according to claim 3, characterized in that: The second preset pressure value is 6000 Psi.

5. The tailpipe plug according to claim 1, characterized in that: The number of emergency pins (110) matches the second preset pressure value.

6. A controllable breakdown pressure tailpipe plug device, characterized in that, include: The tailpipe plug (100) and drill pipe plug (200) as described in any one of claims 1-5.

7. The controllable breakdown pressure tailpipe plug device according to claim 6, characterized in that, The drill pipe rubber plug (200) includes: a drill pipe cup (201), a sleeve (202), a sealing head (203), and a guide head (204); The drill pipe cup (201) is used to clean and scrape the inner wall of the drill pipe. The two drill pipe cups (201) are connected by the sleeve (202). The bottommost drill pipe cup (201) is connected to the guide head (204) through the sealing head (203).

8. A method for applying a controllable pressure puncture tailpipe rubber plug device, comprising using the controllable pressure puncture tailpipe rubber plug device as described in any one of claims 6-7, characterized in that, The method includes the following steps: Conduct ground preparation work, including wellbore circulation cleaning, drilling fluid performance adjustment, and tool inspection; The tail pipe is lowered into place according to the preset pipe string arrangement and cement grouting operation is carried out; The drill pipe plug (200) is delivered, and the tailpipe plug (100) is sheared by pressing it to the first preset pressure value, so that the drill pipe plug (200) and the tailpipe plug (100) are combined into one and continue to descend; When the tailpipe plug (100) encounters obstruction and causes pressure buildup, the emergency shear sleeve (113) is sheared by pressing down to the second preset pressure value, a flow channel is established to continue displacement, and the cementing operation is completed.

9. The application method of the controllable breakdown pressure tailpipe rubber plug device according to claim 8, characterized in that: The first preset pressure value is 2000 Psi; And / or, The second preset pressure value is 6000 Psi.

Images