A digitized wellhead seal device

Abstract

The present application relates to a kind of digital wellhead sealing device, including center short, piston body, encapsulation assembly;Piston body is connected with encapsulation assembly up and down, and is fixed on center short after sleeve setting, flow channel hole ①, flow channel hole ③ are opened at the upper end surface of piston body, flow channel hole ① is connected with annular cavity, flow channel hole ③ is connected with return pipe;Flow channel hole ① is connected with pipeline f, two-position two-way electromagnetic valve A III, pipeline c, external flow channel' in turn;Flow channel hole ③ is connected with pipeline e, two-position two-way electromagnetic valve B III, pipeline d, external flow channel in turn;Two-position two-way electromagnetic valve A III, two-position two-way electromagnetic valve B III are electrically connected with control panel;Lower end of center short is sleeved with lower short that can slide up and down, and lower end of center short is also sleeved with annular pressure sensor;Wireless sensor is installed on lower short.The beneficial effects achieved by the present application are: can be fixed and sealed simultaneously, the whole sealing device is convenient, simple, safe and high, and early warning can be made.

Description

Technical Field

[0001] This invention relates to the field of oil well equipment technology, and in particular to a digital wellhead sealing device. Background Technology

[0002] In the field of oil well cementing, in order to improve cementing efficiency, the method of inserting casing into the drill string is used for cementing. This process requires sealing the annulus between the wellhead casing and the drill string to improve well control safety during the cementing process.

[0003] Existing wellhead sealing devices have the following problems: 1. Structurally, existing sealing devices seal the annulus between the drill string and casing using an inverted flared end. During the running process, the inverted flared end structure often gets stuck with the casing, making running difficult. 2. In terms of cementing methods, existing sealing devices require the addition of a drill string short connector to adjust the fixed distance (fixed to prevent upward force of fluid on the drill string during cementing, or upward force of fluid on the sealing device during emergency well control). However, the length of the short connector is often fixed, so the existing fixing method has poor flexibility and is difficult to fix ideally. 3. Existing wellhead sealing devices cannot monitor changes in the annulus fluid level between the casing and drill string in real time, cannot provide early warning of emergencies during the cementing process, and cannot test the sealing performance between the drill string and casing. Poor sealing will cause the mud in the annulus to mix with the cement slurry, resulting in premature solidification of the cement slurry, affecting cementing and subsequent drill string lifting. This invention proposes a digital wellhead sealing device to solve the above problems, ensuring that the wellhead sealing device is simple and reliable to install and fix, and can detect the wellhead fluid status in real time. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a digital wellhead sealing device that solves the problems of existing cementing sealing devices being cumbersome to operate, lacking flexibility, not being safe enough, and unable to provide early warnings.

[0005] The objective of this invention is achieved through the following technical solution: a digital wellhead sealing device, which is lowered into the wellhead casing, including a central short connector, a piston body, and a sealing assembly; The piston body and the encapsulation assembly are both cylindrical and connected vertically. After they are connected, they are fitted together and fixed on the central short circuit. After they are fitted together, an annular cavity is formed between the two and the central short circuit. After they are fitted together, the two can seal the annular cavity at the upper and lower ends. The piston body has a flow channel hole ① at its upper end face, and the flow channel hole ① is connected to the annular cavity; A flow channel hole ③ is opened at the upper end face of the piston body. A return pipe is provided along the parallel axial direction on the side wall of the piston body and the packaging assembly. The upper end of the return pipe is connected to the flow channel hole ③, and the lower end passes through the lower end face of the packaging assembly. The central short circuit has a central cavity ④ that runs vertically through it; The piston body has a radial piston movement fixing part I, and the piston body also has a flow channel hole ②. The flow channel hole ② can guide the high pressure fluid in the annular cavity to the radial piston movement fixing part I, and allow the fixing part I to move radially along the piston and then abut against the inner wall of the wellhead casing for fixation. The encapsulation assembly has a rubber expansion encapsulation part II and a flow channel hole ⑤. The flow channel hole ⑤ can guide the high-pressure fluid in the annular cavity to the rubber expansion encapsulation part II and allow the rubber expansion encapsulation part II to expand radially and then press against the inner wall of the wellhead casing to seal. The flow channel hole ① is connected in sequence to pipe f, two-position two-way solenoid valve AⅢ, pipe c, and external flow channel; the flow channel hole ③ is connected in sequence to pipe e, two-position two-way solenoid valve BⅢ, pipe d, and external flow channel; two-position two-way solenoid valve AⅢ and two-position two-way solenoid valve BⅢ are electrically connected to the control panel; A lower shorting that can slide up and down is fitted on the lower end of the center shorting. A ring-shaped pressure sensor is also fitted on the lower end of the center shorting. The two ends of the pressure sensor abut against the lower end of the package assembly and the upper end of the lower shorting, respectively. A wireless sensor is installed on the lower shorting and is electrically connected to the pressure sensor. The control panel is also electrically connected to the wireless sensor via a wireless signal receiver IV.

[0006] As a preferred technical solution of this application, the outer cylindrical surface of the lower end of the central short connector has an annular protrusion A; the inner wall of the upper end of the lower short connector has an annular protrusion B. The lower short connector consists of two segments, each with a two-lobed structure. The two clamping segments are clamped at the central short connector, and locking rings B are screwed onto the external threads of the two clamping segments. The annular protrusion B is locked onto the annular protrusion A to limit the movement and prevent it from sliding down.

[0007] Furthermore, the lower short connector is provided with a ring-shaped wireless sensor, and a fixing ring is threaded onto the lower short connector. The two ends of the wireless sensor abut against the locking ring B and the fixing ring.

[0008] As a preferred technical solution of this application, the piston body (20) has multiple stepped holes radially formed on its sidewall; the stepped holes include a large-diameter hole on the outer side and a small-diameter hole on the inner side, the small-diameter hole being the flow channel hole ②. A piston is placed in the large-diameter hole of the stepped hole, and a central blind hole is formed at the outer end of the piston, with a groove formed on the entire cylinder at the outer end of the piston; a spring is placed in the central blind hole, and a pressure strip is placed on the outer side of the stepped hole, and the pressure strip is fixed to the cylinder surface of the piston body by screws. The two ends of the spring abut against the bottom of the central blind hole and the pressure strip, respectively. The pressure strip does not completely block the large-diameter hole and only holds the spring in place. When the piston moves outward, the pressure strip is inserted into the groove, allowing the outer end of the piston to extend out of the stepped hole. Alloy teeth are present on the outer end face of the piston. When the high-pressure fluid injected from the external flow channel enters the annular cavity through the flow channel hole ①, the high-pressure fluid in the annular cavity acts on the piston through the flow channel hole ②, causing the piston to move outward. At this time, the pressure bar is inserted into the groove to avoid blocking the piston's movement, and the outer end of the piston extends out of the stepped hole, allowing the alloy teeth to be pressed into the inner wall of the wellhead casing.

[0009] Furthermore, the piston body has an annular protrusion C on the inner wall of the upper end, and a corresponding annular protrusion D on the outer cylindrical surface of the central short joint; the annular protrusion C is threaded onto the annular protrusion D, so that the piston body is fixed on the central short joint and the upper end of the annular cavity is sealed.

[0010] As a preferred technical solution of this application, the piston body is connected to the packaging assembly via an intermediate connecting cylinder.

[0011] As a preferred technical solution of this application, the encapsulation assembly includes a first connecting cylinder, a second connecting cylinder, an assembly tube, a sealing glue canister, and a sealing cylinder section. The assembly tube is fitted onto the central short connector, forming a partial annular cavity between them. The upper end of the assembly tube is connected to the lower end of the first connecting cylinder, and the upper end of the first connecting cylinder is threaded into the inner wall of the lower end of the intermediate connecting cylinder, with a corresponding sealing ring at the connection. The sealing glue canister is fitted onto the assembly tube, forming an expansion gap VI between them. The upper end of the sealing glue canister is threaded into the outer cylindrical surface of the lower end of the intermediate connecting cylinder. The lower end of the sealing glue canister is connected to the second connecting cylinder, and the lower end of the second connecting cylinder is threaded into the sealing cylinder section, with a corresponding sealing ring at the connection. The sealing cylinder is fitted onto the central short connector, with a corresponding sealing ring between them. The assembly tube has a radially opening flow channel hole ⑤, which connects the annular cavity to the expansion gap VI. When the high-pressure fluid injected from the external flow channel enters the annular cavity through the flow channel hole ①, the high-pressure fluid located in the annular cavity flows into the expansion gap VI through the flow channel hole ⑤, thereby causing the sealing rubber barrel to expand and then contact the inner wall of the assembly tube for sealing.

[0012] The present invention has the following advantages: (1) It can fix and seal at the same time, and the entire sealing device is convenient and simple to install at the wellhead; Specifically, the wellhead sealing device in this invention achieves wellhead sealing by means of a rubber bucket seat. When the tool is not seated during the lowering process, its outer diameter is smaller than the inner diameter of the casing, making lowering convenient and without obstruction. Furthermore, the wellhead sealing device of the present invention fixes the sealing device by pushing the alloy teeth into the inner wall of the casing through liquid pressure, which has a large adjustable range and good adaptability to cementing at any position in the casing. The device in this invention performs sealing and fixing operations simultaneously, which is simple and convenient. (2) High security; Specifically, the piston body and the seat assembly can slide on the central short joint. After cementing is completed, the drill string can be lifted directly without unsealing, and the well can be circulated and flushed (entering from flow channel ④ and exiting from flow channel ③), thereby improving well control safety. (3) It can provide early warnings; This invention allows for real-time monitoring of annular fluid level changes between the casing and drill string, providing early warnings of unexpected situations during cementing, and detecting the sealing performance between the drill string and casing. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the structure of the present invention after removing the upper part of the central short circuit; Figure 3 A schematic diagram of the piston body mounting location; Figure 4 This is a schematic diagram of the structure between the package assembly and the lower shorting. Figure 5 This is a structural diagram of the lower short-circuit installation point; Figure 6 This is a flowchart of the present invention; Figure 7 This is a schematic diagram of the control system of the present invention; Figure 8 A schematic diagram of the piston mounting structure at the piston body; In the diagram: 10 - center short circuit; 20-Piston body, 21-Screw, 22-Pressure bar, 23-Piston, 24-Spring; 30 - Encapsulation assembly; 31 - First connecting sleeve; 32 - Second connecting sleeve; 33 - Assembly tube; 34 - Sealing glue can; 35 - Sealing section. 40-Intermediate connecting cylinder, 50-Lower short circuit, 51-Pressure sensor, 52-Wireless sensor, 53-Locking ring B, 54-Fixing block, 60-Annular cavity, 70-Return pipe. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0015] It should be noted that the orientation or positional relationship indicated by terms such as "left" and "right" is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, or the orientation or positional relationship in which those skilled in the art would conventionally understand it. Such terms are only for the convenience of describing the invention 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, and therefore should not be construed as a limitation of the invention.

[0016] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the present invention can be combined with each other.

[0017] like Figures 1-7 As shown, a digital wellhead sealing device includes a center short circuit 10, a piston body 20, and a sealing assembly 30. Both the piston body 20 and the encapsulation assembly 30 are cylindrical. An intermediate connecting cylinder 40 is gradually fitted onto the lower outer cylindrical surface of the piston body 20 and the upper outer surface of the encapsulation assembly 30, so that the piston body 20 and the encapsulation assembly 30 are connected vertically. After the piston body 20 and the encapsulation assembly 30 are connected, they are fitted together and fixed on the central shorting 10. After the fitting, the two and the central shorting 10 form an annular cavity 60. In addition, the fitting can seal the annular cavity 60 at the upper and lower ends. Among them, a flow channel hole ① is opened at the upper end face of the piston body 20, and the flow channel hole ① is connected to the annular cavity 60; Among them, a flow channel hole ③ is opened at the upper end face of the piston body 20, and a return pipe 70 is provided along the parallel axial direction on the side wall of the piston body 20 and the package assembly 30. The upper end of the return pipe 70 is connected to the flow channel hole ③, and the lower end passes through the lower end face of the package assembly. Among them, the central short-circuit 10 has a central cavity ④ that runs through the upper and lower parts; The piston body 20 has a piston radial movement fixing part I and a flow channel hole ②. The flow channel hole ② can guide the high pressure fluid in the annular cavity 60 to the piston radial movement fixing part I. When the high pressure fluid flows to the piston radial movement fixing part I, the piston radial movement fixing part I moves radially, and then the piston radial movement fixing part I abuts against the inner wall of the wellhead casing, thus completing the fixing of the entire sealing device on the wellhead casing. The encapsulation assembly 30 has a rubber expansion encapsulation part II and a flow channel hole ⑤. The flow channel hole ⑤ can guide the high-pressure fluid in the annular cavity 60 to the rubber expansion encapsulation part II. When the high-pressure fluid flows to the rubber expansion encapsulation part II, the rubber expansion encapsulation part II expands radially and then abuts against the inner wall of the wellhead casing, thus completing the seal between the entire sealing device and the wellhead casing (annular seal of the drill string casing). Furthermore, flow channel ① is connected in sequence to pipe f, two-position two-way solenoid valve AⅢ, pipe c, and external flow channel; flow channel ③ is connected in sequence to pipe e, two-position two-way solenoid valve BⅢ, pipe d, and external flow channel; two-position two-way solenoid valve AⅢ and two-position two-way solenoid valve BⅢ are electrically connected to the control panel; Furthermore, a lower shorting 50 that can slide up and down is fitted onto the lower end of the center shorting 10, and an annular pressure sensor 51 is also fitted onto the lower end of the center shorting 10. The two ends of the pressure sensor 51 abut against the lower end of the package assembly and the upper end of the lower shorting, respectively. A wireless sensor 52 is installed on the lower shorting 50, and the wireless sensor 52 is electrically connected to the pressure sensor 51. The control panel is also electrically connected to the wireless sensor 52 via a wireless signal receiver IV. During operation, the entire sealing device is lowered into the casing at the wellhead. When it reaches the appropriate depth, the pressure sensor 51 can detect the set pressure value. When the pressure sensor 51 detects a certain pressure value, it transmits the corresponding pressure data to the wireless signal receiver IV via a wireless sensor. This allows the control panel to control the corresponding two-position two-way solenoid valve to close pipeline e and open pipeline f, connecting the external flow channel with the flow channel hole ①. The high-pressure liquid injected into the external flow channel can fix the piston body to the inner wall of the wellhead casing via the piston radial action fixing part I. At the same time, it can also allow the sealing assembly 30 to expand via the rubber expansion sealing part II, sealing the sealing assembly with the inner wall of the wellhead casing.

[0018] The installation methods for center shorting and bottom shorting are explained in further detail below.

[0019] See Figure 4 and Figure 5 The outer cylindrical surface at the lower end of the central short connector 10 has an annular protrusion A; the inner wall at the upper end of the lower short connector 50 has an annular protrusion B. The lower short connector 50 consists of two bi-lobed sections. The two clamping sections are clamped at the central short connector 10, and locking rings B53 are screwed onto the external threads of the two clamping sections. The annular protrusion B is stuck on the annular protrusion A to limit the movement and prevent it from sliding down. During operation: When the entire sealing device is lowered, when it is lowered to the appropriate position, the lower end of the lower shorting 50 will abut against a certain position on the wellhead casing (abutting against the appropriate position is the existing technology). The entire sealing device continues to be lowered, so the lower shorting 50 remains stationary, but the encapsulation assembly and the center shorting continue to move downward (so the lower shorting 50 slides upward relative to the encapsulation assembly). Then the upper end of the lower shorting 50 abuts against the pressure sensor, so that the pressure sensor generates a pressure value (this pressure value is transmitted to the control panel via a wireless signal). When the control panel detects that the pressure exceeds the set pressure value (this pressure value is obtained through experiments or empirical values), then pipeline e is closed and pipeline f is opened, and high-pressure liquid is introduced to achieve the fixation of the entire sealing device on the wellhead casing and the annular seal between the entire sealing device and the wellhead casing.

[0020] Furthermore, the installation of the wireless sensor is explained.

[0021] See Figure 5 The lower shorting 50 is fitted with a ring-shaped wireless sensor 52, and a fixing ring 54 is threaded onto the lower shorting 50. The two ends of the wireless sensor 52 abut against the locking ring B53 and the fixing ring 54.

[0022] The structure of the piston body will be further explained below.

[0023] See Figures 1-3 , Figure 8 The piston body 20 has multiple stepped holes radially opened on its side wall; the stepped holes include a large-diameter hole on the outer side and a small-diameter hole on the inner side, which is the flow channel hole ②; A piston 23 is placed inside the large-diameter hole of the stepped hole. The outer end of the piston 23 has an inward-facing central blind hole. The outer end of the piston 23 forms a groove in the entire cylinder. A spring 24 is placed inside the central blind hole. A pressure strip 22 is placed outside the stepped hole and is fixed to the cylindrical surface of the piston body 20 by screws 21. The two ends of the spring 24 abut against the bottom of the central blind hole and the pressure strip 22, respectively. The pressure strip 22 does not completely block the large-diameter hole and does not hold the spring 24 in place. When the piston 23 moves outward, the pressure strip 22 is inserted into the groove, allowing the outer end of the piston 23 to extend out of the stepped hole. The piston 23 has alloy teeth on its outer end face; During operation: After the entire sealing device is lowered to the appropriate position, the high-pressure fluid enters the annular cavity 60 through the external flow channel via pipe c, two-position two-way solenoid valve AⅢ, pipe f, and flow channel hole ①. The high-pressure fluid in the annular cavity 60 then flows into the piston 23 through the flow channel hole ② and acts on the piston 23. The piston 23 moves outward. At this time, the pressure strip 22 is inserted into the groove to avoid blocking the movement of the piston 23. The outer end of the piston 23 extends out of the stepped hole, allowing the alloy teeth to be pressed into the inner wall of the wellhead casing.

[0024] Further, see Figure 3 There is an annular protrusion C on the inner wall of the upper end of the piston body 20, and a corresponding annular protrusion D on the outer cylindrical surface of the central short-circuit 10. During installation: (1) After the annular pressure sensor 51 is fitted under the center short circuit 10, the lower short circuit 50 is clamped and the corresponding wireless sensor 52 is installed on the lower short circuit 50, the center assembly is formed. When the piston body 50 is connected to the package assembly 30, the outer assembly is formed; (2) When the outer assembly is fitted onto the center assembly, the annular protrusion C is threaded onto the annular protrusion D, so that the outer assembly is fixed onto the center assembly. Furthermore, after the outer casing assembly is fixed to the center assembly, the upper end of the annular cavity 60 is sealed by the threaded engagement of the annular protrusion C and the annular protrusion D, and the lower end of the annular cavity 60 is sealed by the engagement of the encapsulation assembly 30 with the center short circuit 10.

[0025] The structure of the package assembly will be further explained below.

[0026] See Figure 4 The encapsulation assembly 30 includes a first connecting cylinder 31, a second connecting cylinder 32, an assembly tube 33, a sealing glue can 34, and a sealing cylinder section 35; The assembly tube 33 is fitted onto the central short connector 10, forming a partial annular cavity 60 between them; and the upper end of the assembly tube 33 is connected to the lower end of the first connecting tube 31; in addition, the upper end of the first connecting tube 31 is threaded into the lower end of the intermediate connecting tube 40, and the connection has a corresponding sealing ring. Among them, the sealing glue barrel 34 is fitted outside the assembly tube 33, and an expansion gap VI is formed between the two. The upper end of the sealing glue barrel 34 is threaded with the outer cylindrical surface of the lower end of the intermediate connecting tube 40. The lower end of the sealing glue barrel 34 is connected to the second connecting cylinder 32, the lower end of the second connecting cylinder 32 is threadedly connected to the sealing cylinder section 35, and a corresponding sealing ring is provided at the connection. The sealing cylinder 36 is sleeved on the central shorting 10 and a corresponding sealing ring is provided between the two. Among them, the assembly tube 33 has a flow channel hole ⑤ in the radial direction, and the flow channel hole ⑤ connects the annular cavity 60 with the expansion gap VI; During operation: After the entire sealing device is lowered to the appropriate position, the high-pressure fluid enters the annular cavity 60 through the external flow channel via pipe c, two-position two-way solenoid valve AⅢ, pipe f, and flow channel hole ①. The high-pressure fluid in the annular cavity 60 then flows into the expansion gap VI through the flow channel hole ⑤, thereby causing the sealing rubber barrel 34 to expand. When the sealing rubber barrel 34 expands, it contacts the inner wall of the wellhead casing, thereby sealing the annulus between the entire sealing device and the wellhead casing.

[0027] The installation of the return pipe will be further explained below.

[0028] See Figure 1 and Figure 2 A flow channel hole ③ is opened at the upper end face of the piston body 20. Corresponding mounting elongated holes are opened along the parallel axial direction on the side walls of the piston body 20 and the package assembly 30. A return pipe 70 is installed in the mounting elongated hole. The upper end of the return pipe 70 is connected to the flow channel hole ③, and the lower end of the return pipe 70 penetrates the lower end face of the package assembly 30. During operation: After the entire sealing device is lowered to the appropriate position and fixed and sealed by the corresponding high-pressure fluid route (the route is: high-pressure fluid enters the annular cavity 60 through the external flow channel via pipe c, two-position two-way solenoid valve AⅢ, pipe f, and flow channel hole ①, and the high-pressure fluid in the annular cavity 60 simultaneously flows into flow channel hole ② and flow channel hole ⑤ for corresponding fixing and sealing), it is also necessary to perform a pressure test on the annulus formed between the entire sealing device and the wellhead casing; During the pressure test, the high-pressure fluid in the annular cavity 60 is maintained in a fixed and sealed state. Then, another high-pressure fluid is allowed to flow into the return pipe 60 through pipe d, two-position two-way solenoid valve BⅢ, pipe e, and flow port ③ to achieve pressure testing of the annulus between the sealing device and the wellhead casing. After the test is passed (how to pass the test is existing technology), the high-pressure fluid in the annulus between the sealing device and the wellhead casing is discharged. Then, subsequent work is carried out through the central cavity ④.

[0029] It should be noted that this scheme has multiple working states: (1) Fixing and sealing state: High-pressure fluid is injected into the annular cavity 60 through the external flow channel via pipe c, two-position two-way solenoid valve AⅢ, pipe f, and flow channel hole ①. The high-pressure fluid in the annular cavity 60 simultaneously flows into flow channel hole ② and flow channel hole ⑤ for corresponding fixing and sealing; (2) Annular pressure test state: Another high-pressure fluid flows into the return pipe 60 through pipe d, two-position two-way solenoid valve BⅢ, pipe e, and flow channel hole ③ to realize the pressure test of the annulus between the sealing device and the wellhead casing; (3) Releasing high-pressure fluid from the annulus: The high-pressure fluid in the annulus is released in reverse through the corresponding pipeline of flow channel hole ③; (4) Subsequent working state: Maintain cementing and sealing, and carry out corresponding subsequent work through the central cavity ④; (5) Contact fixing and unsealing state: The high-pressure fluid in the annular cavity is released in reverse through the corresponding pipeline of flow channel hole ①.

[0030] In this solution, the workflow is as follows: Figure 6 As shown: First, pipe f is connected to flow channel ①, and pipe e is connected to flow channel ③. The entire wellhead sealing device is connected to the drill string through the upper end of the central short connector, and then they are lowered together to the designated position. Once inserted, the pressure sensor generates an electrical signal under pressure, which is transmitted to the wireless transmitter-receiver. The receiver then transmits the signal to the control panel. The control panel controls the two-position three-way solenoid valve to close the flow channel e, allowing fluid to be injected from the pipe f. This causes the rubber barrel seat to seal the annulus between the casing and the drill string (i.e., the rubber barrel seat expands and presses against the inner wall of the wellhead casing). At the same time, the piston extends, causing the carbide teeth on the pressure strip to engage with the wellhead casing, thus achieving fixation. Then, via the control panel, fluid is injected from the two-position three-way solenoid valve through pipe e into the annulus of the drill string and casing for pressure testing. If a pressure drop warning occurs during the pressure test, the contingency plan is followed. If the pressure test is successful and pressure is released, pipe e is closed, and cementing begins. Pressure and level sensors monitor annulus level changes in real time. If a level change warning occurs during cementing, the contingency plan is followed. If the level is controllable and cementing is completed, the fluid switching device is unsealed via the control panel, fluid flows out from pipe f, and the drill string is lifted.

[0031] It should be noted that the control panel of this solution can be operated manually or automatically controlled via a computer terminal through a programmed program.

[0032] It should be noted that in this scheme, the piston body and the seat assembly can slide on the central short joint. After cementing is completed, there is no need to unseal the assembly. The drill string can be lifted directly for circulation flushing (entering from flow channel ④ and exiting from flow channel ③), which improves well control safety.

[0033] The above embodiments only illustrate preferred implementation methods, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this invention, and these all fall within the protection scope of this invention.

Claims

1. A digital wellhead sealing device that is lowered into a wellhead casing, characterized by: Includes a center short circuit (10), a piston body (20), and a package assembly (30); The piston body (20) and the encapsulation assembly (30) are both cylindrical and connected vertically. After they are connected, they are fitted together and fixed on the center short connector (10). After they are fitted together, an annular cavity (60) is formed between the two and the center short connector (10). After they are fitted together, the two can seal the annular cavity (60) at the upper and lower ends. The piston body (20) has a flow channel hole ① at its upper end face, and the flow channel hole ① is connected to the annular cavity (60); The piston body (20) has a flow channel hole ③ at its upper end face. A return pipe (70) is provided along the parallel axial direction on the side wall of the piston body (20) and the encapsulation assembly (30). The upper end of the return pipe (70) is connected to the flow channel hole ③, and the lower end passes through the lower end face of the encapsulation assembly. The central short circuit (10) has a central cavity ④ that runs vertically through the center; The piston body (20) has a piston radial movement fixing part I, and the piston body (20) also has a flow channel hole ②. The flow channel hole ② can guide the high pressure fluid in the annular cavity (60) to the piston radial movement fixing part I, and allow the piston radial movement fixing part I to move radially and then abut against the inner wall of the wellhead casing for fixation. The encapsulation assembly (30) has a rubber expansion encapsulation part II and a flow channel hole ⑤. The flow channel hole ⑤ can guide the high pressure fluid in the annular cavity (60) to the rubber expansion encapsulation part II and allow the rubber expansion encapsulation part II to expand radially and then press against the inner wall of the wellhead casing to seal. The flow channel hole ① is connected in sequence to pipe f, two-position two-way solenoid valve AⅢ, pipe c, and external flow channel; the flow channel hole ③ is connected in sequence to pipe e, two-position two-way solenoid valve BⅢ, pipe d, and external flow channel; two-position two-way solenoid valve AⅢ and two-position two-way solenoid valve BⅢ are electrically connected to the control panel; The lower end of the center short circuit (10) is fitted with a lower short circuit (50) that can slide up and down. The lower end of the center short circuit (10) is also fitted with a ring-shaped pressure sensor (51). The two ends of the pressure sensor (51) abut against the lower end of the package assembly and the upper end of the lower short circuit, respectively. A wireless sensor (52) is installed on the lower short circuit (50). The wireless sensor (52) is electrically connected to the pressure sensor (51). The control panel is also electrically connected to the wireless sensor (52) via a wireless signal receiver IV. The piston body (20) has multiple stepped holes radially opened on its sidewall; The stepped hole includes a large-diameter hole on the outer side and a small-diameter hole on the inner side, which is the flow channel hole ②; A piston (23) is placed inside the large-diameter hole of the stepped hole. The outer end of the piston (23) has an inward-facing central blind hole. The outer end of the piston (23) forms a groove in the entire cylinder. A spring (24) is placed inside the central blind hole. A pressure strip (22) is placed on the outside of the stepped hole. The pressure strip (22) is fixed to the cylinder surface of the piston body (20) by screws (21). The two ends of the spring (24) abut against the bottom of the central blind hole and the pressure strip (22) respectively. The pressure strip (22) does not completely block the large-diameter hole and only holds the spring (24) against it. When the piston (23) moves outward, the pressure strip (22) is inserted into the groove, allowing the outer end of the piston (23) to extend out of the stepped hole. The piston (23) has alloy teeth on its outer end face; When the high-pressure fluid injected from the external flow channel enters the annular cavity (60) through the flow channel hole ①, the high-pressure fluid in the annular cavity acts on the piston (23) through the flow channel hole ②. The piston (23) moves outward. At this time, the pressure bar (22) is inserted into the groove to avoid blocking the movement of the piston (23). After the outer end of the piston (23) extends out of the stepped hole, the alloy teeth are pressed into the inner wall of the wellhead casing. The piston body (20) is connected to the encapsulation assembly (30) via an intermediate connecting cylinder (40); The encapsulation assembly (30) includes a first connecting sleeve (31), a second connecting sleeve (32), an assembly tube (33), a seat sealant can (34), and a sealing sleeve (35); The assembly tube (33) is fitted onto the central short connector (10), forming a partial annular cavity (60) between the two. The upper end of the assembly tube (33) is connected to the lower end of the first connecting tube (31). The upper end of the first connecting tube (31) is threaded into the lower end of the intermediate connecting tube (40), and the connection has a corresponding sealing ring. The sealing rubber barrel (34) is fitted over the assembly tube (33), forming an expansion gap VI between them. The upper end of the sealing rubber barrel (34) is threaded with the lower end of the outer cylindrical surface of the intermediate connecting tube (40). The lower end of the seat seal barrel (34) is connected to the second connecting cylinder (32), the lower end of the second connecting cylinder (32) is threadedly connected to the sealing cylinder section (35), and a corresponding sealing ring is provided at the connection. The sealing cylinder (36) is sleeved on the center short connector (10), and a corresponding sealing ring is provided between the two. The assembly tube (33) has a radially opening flow channel hole ⑤, which connects the annular cavity (60) with the expansion gap VI; When the high-pressure fluid injected from the external flow channel enters the annular cavity (60) through the flow channel hole ①, the high-pressure fluid in the annular cavity flows into the expansion gap VI through the flow channel hole ⑤, thereby causing the seat seal barrel (34) to expand and then contact the inner wall of the assembly tube to seal.

2. A digital wellhead sealing device according to claim 1, characterized in that: The outer cylindrical surface of the lower end of the central short circuit (10) has an annular protrusion A; The upper inner wall of the lower short connector (50) has an annular protrusion B. The lower short connector (50) consists of two segments, each with a two-lobed structure. The two clamping segments are clamped at the center short connector (10), and locking rings B (53) are screwed onto the external threads of the two clamping segments. The annular protrusion B is locked onto the annular protrusion A to limit the movement and prevent it from sliding down.

3. A digital wellhead sealing device according to claim 2, characterized in that: The lower short circuit (50) is fitted with a ring-shaped wireless sensor (52), and a fixing ring (54) is threaded onto the lower short circuit (50). The two ends of the wireless sensor (52) abut against the locking ring B (53) and the fixing ring (54).

4. A digital wellhead sealing device according to claim 1, characterized in that: The piston body (20) has an annular protrusion C on the inner wall at the upper end, and a corresponding annular protrusion D on the outer cylindrical surface of the central short connection (10); The annular protrusion C is threaded onto the annular protrusion D, so that the piston body is fixed on the central short joint and the upper end of the annular cavity (60) is sealed.

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