Wellhead shielding device for assisting wellbore annulus liquid level detection and use method

Abstract

The invention discloses a wellhead shielding device for assisting in wellbore annulus liquid level detection and a using method. Plugging plates are additionally arranged on the two sides of a wellbore, the plugging plates are driven by a driving assembly to move, arc-shaped grooves are formed in the plugging plates, the horizontal heights of the two plugging plates are different, and when a well is empty and a wellhead needs to be plugged, the plugging plates are driven by the driving assembly to move; the two plugging plates are driven to move towards the well mouth, the two plugging plates are gradually staggered and overlapped up and down, then the well mouth is sealed, during tripping and tripping and when the two plugging plates move towards the well mouth, the grooves in the plugging plates can be clamped and clasped with a drill rod, annular sealing of the well mouth is achieved, a blowout preventer switch can be not needed, frequent switching of the blowout preventer is not needed, and operation is convenient. The damage and failure risks of the blowout preventer are reduced, continuous monitoring of the wellbore annulus liquid level is achieved in the drilling full operation cycle of drilling, tripping, empty well, casing running, well cementation and the like, the accuracy and timeliness of measurement of the annulus liquid level monitoring system are improved, well control safety is facilitated, and the well control risks are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas exploration and production, and relates to a wellhead shielding device for assisting wellbore annulus liquid level detection and a use method thereof. Background Art

[0002] The pressure to develop oil and gas fields is increasing, especially in the Tarim Oilfield, a major oil and gas exploration and development area in my country. The Tarim Oilfield, with its numerous "three-high" wells, complex geology, and challenging construction, is plagued by frequent lost circulation and resulting overflows, posing significant well control safety risks. Maintaining the annular fluid level during drilling is crucial for maintaining bottomhole pressure balance. If the annular fluid level drops, the annular fluid pressure can no longer balance the formation pressure, leading to overflows or blowouts.

[0003] When the liquid level is not at the wellhead, accurately obtaining the downhole liquid level is the key to well control safety. The wellbore annulus liquid level monitoring system can timely monitor the wellbore annulus liquid level when the liquid level is not at the wellhead, accurately obtain liquid level data, guide the maintenance of the wellbore annulus liquid column pressure, and maintain the bottomhole pressure balance. It is one of the key measures to prevent overflow and blowout accidents.

[0004] Ultrasonic liquid level measurement uses ultrasonic waves emitted from a sound wave source to measure the time required for the ultrasonic waves to reflect back after reaching the measured liquid level surface. The measurement is performed based on the principle that this time is proportional to the liquid level. The microprocessor in the ultrasonic liquid level system can quickly and accurately calculate the distance between the sensor and the object being measured, thereby monitoring the liquid level height in the wellbore annulus.

[0005] An ultrasonic signal emitted by a sensor installed outside the #1 four-way valve or in a reserved position on the kill manifold reflects off the wellbore annulus liquid surface and returns to the sensor's signal receiving end, generating a pulse. The liquid level is measured by measuring the time difference between the ultrasonic and reflected signals. However, traditional methods for collecting downhole liquid level data require the closure of the annular BOP or ram BOP, creating an obstruction at the wellhead and preventing data acquisition. During drilling, tripping, and other casing and cementing operations, shutting down the BOP requires interrupting operations. Frequently opening and closing the BOP complicates the operation, damages the BOP, and increases well control risks. Failure to measure the liquid level when it's not at the wellhead also delays timely monitoring by the wellbore annular liquid level monitoring system, preventing any drop in the annular liquid level from being detected. This poses a risk of overflow or blowout, creating safety hazards and preventing remote, automatic, and continuous liquid level measurement. Currently, there is no equipment or method in the oil exploration and development field that can monitor liquid levels throughout the entire drilling cycle without the use of a BOP. Summary of the Invention

[0006] The purpose of the present invention is to solve the problem in the prior art that when measuring the liquid level in the wellbore, the traditional method requires closing the annular blowout preventer or the gate blowout preventer to form a blockage at the wellhead. However, during drilling, tripping, and other casing and cementing conditions, closing the blowout preventer requires interrupting the operation, and the frequent opening and closing of the blowout preventer is complicated, may damage the blowout preventer, and increase the risk of well control. A wellhead blocking device and a method for use are provided for assisting the detection of the liquid level in the wellbore annulus.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A wellhead shielding device for assisting in the detection of the liquid level in the annulus of a wellbore includes drive assemblies respectively arranged on both sides of the wellbore, a sealing plate is provided at the driving end of each drive assembly, arc-shaped grooves are provided on the end faces of the sealing plates that are close to each other, and the horizontal height of the sealing plate on one side is greater than that of the sealing plate on the other side.

[0009] A further improvement of the present invention is:

[0010] The blocking plate is fixed on a blocking plate supporting plate, and the blocking plate supporting plate is connected to a driving assembly.

[0011] The blocking plate is rigidly connected to the blocking plate supporting plate.

[0012] The blocking plate and the blocking plate supporting plate are connected by bolts.

[0013] The blocking plate support plate is connected to the driving assembly through a connector.

[0014] The driving assembly includes a cylinder connected to an air source.

[0015] The air source and the air cylinder are communicated with each other through a compressed air pipeline.

[0016] It also includes a shutter frame, which is sleeved on the outside of the wellbore;

[0017] The driving assembly is located on one side of the shutter frame, and the driving end of the driving assembly extends into the interior of the shutter frame.

[0018] An upper cover plate is provided at the upper end of the shutter frame, and a lower cover plate is provided at the lower end.

[0019] A method for using a wellhead shielding device for assisting wellbore annulus liquid level detection comprises the following steps:

[0020] When the well is empty, the drive assemblies on both sides drive the corresponding plugging plates to move toward the wellhead. At this time, the two plugging plates gradually overlap until the wellhead is completely closed. When the well needs to be opened, the drive assembly drives the plugging plates in the opposite direction, and the two plugging plates gradually separate, and the wellhead is opened.

[0021] When drilling, the drill pipe is extended into the wellbore, and the sealing plate is driven to move toward the wellhead. At this time, the arc-shaped groove on the sealing plate is clamped on the outside of the drill pipe. When the drill pipe is lifted to the coupling, the driving assembly drives the sealing plate in the reverse direction. At this time, the coupling passes through the two sealing plates. When the coupling completely passes through the sealing plates, the driving assembly drives the sealing plate toward the wellhead again. The arc-shaped groove of the sealing plate is clamped on the outside of the drill pipe again, forming an annular closed space at the wellhead.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention discloses a wellhead shielding device for assisting wellbore annular space liquid level detection, wherein sealing plates are added on both sides of the wellbore, the sealing plates move under the drive of a driving assembly, and arc-shaped grooves are provided on the sealing plates, and the horizontal heights of the two sealing plates are different. When the well is empty and the wellhead needs to be sealed, the two sealing plates are driven to move toward the wellhead, and the two sealing plates gradually overlap up and down, and then the wellhead is sealed. When drilling, when the two sealing plates move toward the wellhead, the grooves on the sealing plates can be clamped and held tightly with the drill pipe to achieve an annular seal of the wellhead. Although arc-shaped grooves are provided on both sealing plates, shaped grooves, but the horizontal heights of the two sealing plates are different, so when the well is empty, the grooves on the two sealing plates will not interfere with each other, and the wellhead sealing will be achieved by up and down dislocation during movement, meeting the wellhead sealing needs in different states, and can be done without the help of the blowout preventer switch, and there is no need for frequent switching of the blowout preventer, which reduces the damage and failure risk of the blowout preventer, and realizes continuous monitoring of the wellbore annulus liquid level during the entire drilling operation cycle such as drilling, tripping, empty well, casing running, and cementing. The device improves the accuracy and timeliness of the annulus liquid level monitoring system measurement, is beneficial to well control safety, improves drilling operation efficiency, and reduces well control risks.

[0024] Furthermore, in the present invention, the blocking plate is fixed on a blocking plate supporting plate, and the blocking plate supporting plate is connected to a driving assembly, thereby improving the stability of the blocking plate fixation.

[0025] Furthermore, the present invention also includes a shielding frame, with an upper cover plate provided at the upper end and a lower cover plate provided at the lower end to shield the blocking plate and prevent external falling objects from affecting the normal operation of the blocking plate.

[0026] The present invention discloses a method for using a wellhead shielding device for assisting in the detection of the liquid level in the annulus of a wellbore. When the well is empty, the driving assemblies on both sides drive the corresponding sealing plates to move toward the wellhead, and the two sealing plates gradually overlap by being displaced up and down. Therefore, when the well is empty, the grooves on the two sealing plates will not interfere with each other, and the wellhead sealing will be achieved by the up and down dislocation during movement. When drilling is being lifted or lowered, the two sealing plates move toward the wellhead, and the grooves on the sealing plates can be clamped and tightly engaged with the drill pipe to achieve an annular seal of the wellhead. This method can meet the wellhead sealing requirements in different states, and can realize continuous monitoring of the liquid level in the annulus of the wellbore during the entire drilling operation cycle such as drilling, lifting or lowering the drill pipe, empty well, casing installation, and cementing without the aid of a blowout preventer switch. This device improves the accuracy and timeliness of the measurement of the annulus liquid level monitoring system, is beneficial to well control safety, improves drilling operation efficiency, and reduces well control risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 It is the overall structural diagram of the present invention;

[0029] Figure 2 This is an overall structural diagram of a drill rod of the present invention;

[0030] Figure 3 For the present invention Figure 2 A top view of

[0031] Figure 4 This is a schematic diagram of the upper and lower misalignment of the blocking plate of the present invention;

[0032] Figure 5 The present invention has a state diagram of a drilling tool;

[0033] Figure 6 This is a state diagram of the present invention without a drilling tool.

[0034] Among them: 1-air source; 2-compressed air pipeline; 3-air control cabinet; 4-inlet; 5-sealing plate; 6-sealing plate support; 7-connector; 8-lower cover; 9-upper cover; 10-shutter frame; 11-cylinder; 12-air source connector; 13-drill pipe; 14-flange. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0037] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0038] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the inventive product is typically placed when in use. These terms are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0039] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0040] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. 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; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0041] The present invention is described in further detail below with reference to the accompanying drawings:

[0042] See also Figures 1 to 6 The embodiment of the present invention discloses a wellhead shielding device for assisting in the detection of the wellbore annulus liquid level. This device installs a set of wellbore annulus shielding devices on the wellhead guide pipe to replace the blowout preventer that is closed during the monitoring of the wellbore annulus liquid level. The wellbore annulus shielding device mainly adopts a slide to straighten the sealing plate, so that the sealing plate slides along the slide. Under the action of the double-acting cylinder, the sealing plate can completely seal the wellbore in the empty well state; under the drilling condition, it can hold the drill pipe tightly; when large-sized drilling tools pass through, it can be fully opened to allow large-sized drilling tools to pass smoothly. During the drilling operation, it plays the role of sealing the wellbore annulus, and cooperates with the ultrasonic liquid level measuring instrument to realize remote automatic continuous measurement of the wellbore annulus liquid level, improve the measurement accuracy of the annulus liquid level monitoring system, and is beneficial to well control safety; at the same time, it can also scrape the drilling fluid on the outer wall of the drill pipe when drilling, reducing drilling fluid environmental pollution. The device is easy to install and simple to operate.

[0043] Specifically including the following structures:

[0044] Example 1

[0045] The present embodiment discloses a wellhead shielding device for assisting in the detection of the liquid level in the annulus of the wellbore, which is characterized in that it includes driving components respectively arranged on both sides of the wellbore, and a sealing plate 5 is provided at the driving end of each driving component, and arc-shaped grooves are provided on the end faces of the sealing plates 5 that are close to each other, and the horizontal height of the sealing plate 5 on one side is greater than the horizontal height of the sealing plate 5 on the other side.

[0046] In this embodiment, in order to seal the wellhead when the well is empty and the two arc-shaped grooves do not affect each other, the horizontal heights of the two blocking plates 5 are set to be different, and the height of one blocking plate 5 is greater than the height of the other blocking plate 5. When the two blocking plates 5 move toward the wellhead at the same time, Figure 6 The two blocking plates 5 are staggered up and down, and the staggered part can block part of the arc-shaped groove, thereby achieving sealing of the wellhead in the empty well state.

[0047] Example 2

[0048] This embodiment discloses a wellhead shielding device for assisting wellbore annulus liquid level detection, characterized by including drive assemblies disposed on both sides of the wellbore, each drive assembly having a sealing plate 5 disposed at the drive end thereof, arc-shaped grooves formed on the adjacent end faces of the sealing plates 5, and a sealing plate 5 on one side having a greater height than the sealing plate 5 on the other side. The sealing plates 5 are fixed to a sealing plate support plate 6, which is connected to the drive assemblies.

[0049] In this embodiment, the blocking plate supporting plate 6 is mainly used to support the blocking plate 5 , wherein the blocking plate supporting plate 6 has a concave step surface, and the blocking plate 5 is fixed on the concave step surface, thereby improving the stability of the support for the blocking plate 5 .

[0050] Furthermore, in this embodiment, the blocking plate 5 is rigidly connected to the blocking plate supporting plate 6. Specifically, the connection method disclosed in this embodiment is that the blocking plate 5 and the blocking plate supporting plate 6 are connected by bolts.

[0051] Example 3

[0052] This embodiment discloses a wellhead shielding device for assisting in wellbore annulus liquid level detection, characterized by including drive assemblies disposed on either side of the wellbore, each drive assembly being provided with a blocking plate 5 at its drive end, with arc-shaped grooves defined on adjacent end surfaces of the blocking plates 5, wherein the horizontal height of the blocking plates 5 on one side is greater than that of the blocking plates 5 on the other side. The drive assembly includes a cylinder 11, which is connected to a gas source 1.

[0053] Specifically, in this embodiment, the gas source 1 provides gas source for the cylinder 11, and the gas source 1 is connected to the cylinder 11 through the compressed air pipeline 2 and the gas source street 12 to supply gas to the cylinder 11. The gas source 1 is connected to the gas control cabinet 3, and a three-position four-way switch is arranged on the gas control cabinet 3.

[0054] In this embodiment, the cylinder 11 is a double-acting cylinder.

[0055] In this embodiment, by operating the three-position four-way air switch of the air control cabinet 3, the air source 1 supplies air to the double-acting cylinder through the compressed air pipeline 2 and the air source connector 12. After the air is supplied, the piston rod of the double-acting cylinder 11 drives the sealing plate to move.

[0056] Example 4

[0057] This embodiment discloses a wellhead shielding device for assisting in wellbore annular space liquid level detection. The device is characterized by comprising drive assemblies disposed on either side of the wellbore, each drive assembly having a sealing plate 5 disposed at its driving end. The adjacent end surfaces of the sealing plates 5 each have an arcuate groove, with the sealing plates 5 on one side having a greater height than the other. The device also includes a shielding frame 10, which is sleeved onto the outside of the wellbore. The drive assembly is located on one side of the shielding frame 10, with the driving end of the drive assembly extending into the interior of the shielding frame 10.

[0058] Furthermore, an upper cover plate 9 is provided at the upper end of the shutter frame 10 , and a lower cover plate 8 is provided at the lower end.

[0059] In this embodiment, the shutter frame 10 is mainly used to shield the driving end of the cylinder 11 and the shielding plate 5 to prevent the main part of the device from being exposed.

[0060] This embodiment also discloses a method for using a wellhead shielding device for assisting wellbore annulus liquid level detection, comprising the following steps:

[0061] When the well is empty, operate the three-position four-way air switch of the air control cabinet 3, and the air source 1 supplies air to the double-acting cylinder 11 through the compressed air pipeline 2 and the air source connector 12. After the air is supplied, the piston rod of the double-acting cylinder 11 slides toward the wellhead, and the sealing plate 5 completely closes the wellhead, which can effectively protect the echo signal, improve the sensor signal collection capability, and ensure the continuous monitoring of the wellbore liquid level monitoring system;

[0062] When it is necessary to open the well, operate the three-position four-way switch of the air control cabinet 3, and the air source 1 supplies air to the double-acting cylinder in the reverse direction through the compressed air pipeline 2 and the air source connector 12. After the air is supplied, the piston rod of the double-acting cylinder slides in the reverse direction to open the wellhead.

[0063] When tripping, operate the three-position four-way air switch of the air control cabinet 3, and the air source 1 supplies air to the double-acting cylinder through the compressed air pipeline 2 and the air source connector 12. After the air is supplied, the piston rod of the double-acting cylinder 11 slides toward the wellhead, and the annular pressure plate of the sealing plate 5 is attached to the outer wall of the drill pipe 13. When the drill pipe 13 is lifted to the coupling, the pressure on the double-acting cylinder 11 exceeds the set value, and the three-position four-way switch of the air control cabinet 3 is reversed. The piston rod of the double-acting cylinder moves in the opposite direction, allowing the coupling to pass through the sealing plate 5;

[0064] When the coupling of the drill pipe 13 passes through the sealing plate 5, the pressure on the double-acting cylinder is lower than the set value, the three-position four-way of the air control cabinet 3 is opened in the forward direction, the piston rod slides toward the wellhead, and the annular pressure plate of the sealing plate 5 is attached to the outer wall of the drill pipe 13. That is to say, the front end of the annular pressure plate of the sealing plate 5 always maintains a certain pressure, which can completely close the annular space, ensure the continuous measurement of the wellbore annulus liquid level monitoring system, and timely detect well leakage and overflow.

[0065] When large-sized drilling tools (drill bits, etc.) pass through, the three-position four-way air switch of the air control cabinet 3 is operated, and the air source 1 supplies air to the double-acting cylinder 11 through the compressed air pipeline 2 and the air source connector 12. After the air is supplied, the piston rod of the double-acting cylinder 11 slides away from the wellhead, and the sealing plate 5 slides outward with the piston rod, and the diameter increases, so that the large-sized drilling tools cannot touch the sealing plate. After the large-sized drilling tools pass through, the three-position four-way air switch of the air control cabinet 3 is operated, and the air source 1 supplies air to the double-acting cylinder through the compressed air pipeline 2 and the air source connector 12. After the air is supplied, the piston rod of the double-acting cylinder slides toward the wellhead, and the sealing plate 5 completely closes the wellhead, or closes the drill pipe 13 as in the drilling condition. This can effectively protect the echo signal, improve the sensor signal collection capability, and ensure continuous monitoring of the wellbore liquid level monitoring system.

[0066] This embodiment takes the tripping and drilling conditions to realize the continuous monitoring of the wellbore annulus liquid level as an example.

[0067] The specifications are 13 3 / 8" overflow prevention tube, 5 7 / 8" drill pipe, gas source rated pressure of 0.4-0.6MPa; temperature is ambient temperature 10-40℃.

[0068] The specific implementation steps are as follows:

[0069] Step 1:

[0070] Generally, the wellbore annulus liquid level monitoring device is installed on the outside of the four-way 1# valve or the reserved position of the wellbore pressure manifold. The ultrasonic signal emitted by its sensor is reflected by the wellbore annulus liquid surface back to the signal receiving end of the sensor, and a pulse is output on the sensor. The liquid level is measured by measuring the time difference between the ultrasonic wave and the reflected signal. However, the annular blowout preventer needs to be closed when collecting downhole liquid level data, otherwise the data signal cannot be collected. Based on this, we install the wellbore annulus liquid level monitoring wellhead shielding device on the overflow prevention pipe above the annular blowout preventer to replace the annular blowout preventer when monitoring the wellbore annulus liquid level, and realize the monitoring of the annular liquid level under various drilling operation conditions.

[0071] The wellbore annulus liquid level monitoring wellhead shielding device for lost circulation is connected to the gas source 1 at the drilling site through a compressed air pipeline 2 and a gas source connector 12 to ensure that the working pressure of the gas source is 0.4-0.6 MPa.

[0072] The wellhead shielding device for monitoring the liquid level in the annular space of the wellbore is connected to the overflow prevention pipe through the flange 14 and the connecting bolts. The wellhead shielding device should be kept in a horizontal state as much as possible to allow the sealing plate support plate to move smoothly on the slideway and reduce friction resistance.

[0073] The inlet 4 must be aligned with the drill rig turntable to ensure smooth up and down movement of downhole tools.

[0074] For air source 1, considering the pressure and displacement, it is recommended to use an air compressor with a pressure of not less than 1.0 MPa.

[0075] Step 2:

[0076] The flange of the wellhead shielding device is connected to the wellhead bell flange for monitoring the liquid level in the annular space of the wellbore. Gaskets are used between the flanges. After alignment, bolts are connected and tightened with a wrench to ensure that the flanges are leak-proof.

[0077] After the air pressure pipeline is connected, remove the air source connector 12, open the valve, and purge the air pressure pipeline. After the pipeline is clean, connect the air source connector 12 and perform a sealing test on the entire pipeline under the rated pressure. Maintain the pressure for 10 minutes, with no pressure drop as the standard.

[0078] Step 3:

[0079] To test the function of the blocking device, first place a 5 7 / 8" drill pipe 13 at the wellhead. Operate the three-position, four-way air switch of the air control cabinet 3. Air is supplied from the air source 1 through the compressed air pipeline 2 and the air source connector 12 to the double-acting cylinder. After the air is supplied, the piston rod of the double-acting cylinder slides toward the wellhead. The annular pressure plate of the sealing plate 5 is attached to the outer wall of the drill pipe 13. The drill pipe 13 is lifted to allow the drill pipe coupling to pass through the wellhead blocking device. At this time, the pressure on the double-acting cylinder exceeds the set value. The three-position, four-way air switch of the air control cabinet 3 is opened in the reverse direction. The piston rod of the double-acting cylinder moves in the reverse direction, allowing the coupling to pass through the sealing plate 5.

[0080] After the coupling of drill pipe 13 passes through blocking plate 5, the pressure on the double-acting cylinder falls below the set value. The three-position, four-way valve of air control cabinet 3 opens in the forward direction, the piston rod slides toward the wellhead, and the annular pressure plate of blocking plate 5 again adheres to the outer wall of drill pipe 13, ensuring that the wellhead is completely sealed for 5 minutes. The three-position, four-way air switch of air control cabinet 3 is operated, and air source 1 supplies air in the reverse direction to the double-acting cylinder through compressed air pipeline 2 and air source connector 12. After air is supplied, the double-acting cylinder piston rod slides away from the wellhead, and blocking plate 5 moves away from the wellhead. At this time, the obstructer is in the open position, the air source valve is closed, and the drill pipe 13 is lifted to the drilling platform. Throughout the test process, the air source pressure is stable, and the equipment operates smoothly without any jamming.

[0081] Step 4:

[0082] Confirm that the installation is correct, check the position of the gas pipeline and the device switch; when starting to drill, implement the shielding function of the wellhead shielding device and the wellbore annulus liquid level monitoring.

[0083] The well crew begins downhole operations, opens the air source valve, and operates the three-position, four-way air switch on air control cabinet 3. Air from air source 1 is supplied to double-acting cylinder 11 through compressed air pipeline 2 and air source connector 12. After air is supplied, the piston rod of double-acting cylinder 11 slides toward the wellhead, and the annular pressure plate of sealing plate 5 abuts against the outer wall of drill pipe 13. The wellbore annulus liquid level test begins. The system air source pressure, the annular seal of the obstructer, and the annular liquid level monitoring signal are observed.

[0084] When there is a drilling tool in the well, the drill rod 13 is extended into the wellbore, and the blocking plate 5 is driven to move toward the wellhead. At this time, the arc groove on the blocking plate 5 is clamped on the outside of the drill rod 13 to achieve wellhead blocking.

[0085] The device disclosed in the present invention can realize continuous monitoring of the wellbore annulus liquid level during the entire drilling operation cycle such as drilling, tripping, empty well, casing running, and cementing without the help of a blowout preventer switch. The device has the characteristics of quick installation, easy operation, explosion-proof safety, etc. The device replaces the need to use a blowout preventer to switch to achieve the purpose of wellbore shielding, does not require the blowout preventer to be frequently switched on and off, and reduces the risk of damage and failure of the blowout preventer.

[0086] This device is installed on the overflow prevention pipe, and its structural design features an adjustable closure size, which can adapt to empty wells, drill tools and pipes of different sizes, and is applicable to all wellbore operating conditions. It is driven by a cylinder and has a circuit-free design. It is safe, reliable, remotely controlled and explosion-proof, making it fully suitable for use in wellhead environments. The device has a simple overall structure, is easy to install and operate, and can be continuously monitored, making it suitable for use on-site in drilling and workover operations.

[0087] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A wellhead shielding device for assisting wellbore annulus liquid level detection, characterized in that: The invention comprises driving components respectively arranged on both sides of the wellbore, wherein a sealing plate (5) is arranged at the driving end of each driving component, arc-shaped grooves are provided on the adjacent end faces of the sealing plates (5), and the horizontal height of the sealing plate (5) on one side is greater than the horizontal height of the sealing plate (5) on the other side.

2. A wellhead shielding device for assisting wellbore annulus liquid level detection according to claim 1, characterized in that: The blocking plate (5) is fixed on a blocking plate support plate (6), and the blocking plate support plate (6) is connected to a drive assembly.

3. A wellhead shielding device for assisting wellbore annulus liquid level detection according to claim 2, characterized in that: The blocking plate (5) is rigidly connected to the blocking plate supporting plate (6).

4. A wellhead shielding device for assisting wellbore annulus liquid level detection according to claim 3, characterized in that: The blocking plate (5) and the blocking plate supporting plate (6) are connected via bolts.

5. The wellhead shielding device for assisting wellbore annulus liquid level detection according to claim 2, characterized in that: The blocking plate support plate (6) is connected to the driving assembly via a connector (7).

6. A wellhead shielding device for assisting wellbore annulus liquid level detection according to claim 1, characterized in that: The driving assembly comprises a cylinder (11), and the cylinder (11) is connected to an air source (1).

7. A wellhead shielding device for assisting wellbore annulus liquid level detection according to claim 6, characterized in that: The air source (1) and the air cylinder (11) are connected via a compressed air pipeline (2).

8. The wellhead shielding device for assisting wellbore annulus liquid level detection according to claim 1, characterized in that: It also includes a shutter frame (10), wherein the shutter frame (10) is sleeved on the outside of the wellbore; The driving assembly is located on one side of the shutter frame (10), and the driving end of the driving assembly extends into the interior of the shutter frame (10).

9. A wellhead shielding device for assisting wellbore annulus liquid level detection according to claim 8, characterized in that: An upper cover plate (9) is provided at the upper end of the shutter frame (10), and a lower cover plate (8) is provided at the lower end.

10. A method for using a wellhead shielding device for assisting wellbore annulus liquid level detection, characterized in that: The following steps are involved: When the well is empty, the driving components on both sides drive the corresponding blocking plates (5) to move toward the wellhead. At this time, the two blocking plates (5) gradually overlap until the wellhead is completely closed. When the well needs to be opened, the driving components drive the blocking plates (5) in the opposite direction. The two blocking plates (5) gradually separate and the wellhead is opened. When drilling, the drill rod (13) is extended into the wellbore, and the blocking plate (5) is driven to move toward the wellhead. At this time, the arc-shaped groove on the blocking plate (5) is clamped on the outside of the drill rod (13). When the drill rod (13) is lifted to the coupling, the driving component drives the blocking plate (5) in the reverse direction. At this time, the coupling passes through the two blocking plates (5). After the coupling completely passes through the blocking plates (5), the driving component drives the blocking plate (5) toward the wellhead again. The arc-shaped groove of the blocking plate (5) is clamped on the outside of the drill rod (13) again, forming an annular closed space at the wellhead.

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