Electric subsurface safety valve and using method thereof

Abstract

The invention discloses an electric subsurface safety valve and a using method thereof. The subsurface safety valve comprises a body assembly, an inner pipe assembly and a flat valve, wherein the inner pipe assembly and the flat valve are arranged in the body assembly; the inner pipe assembly comprises a central pipe, a secondary stage of the linear motor and a primary stage of the linear motor; wherein the secondary stage of the linear motor is one section of the central pipe, or the secondary stage of the linear motor is connected with the central pipe; a first cavity is formed between the body assembly and the secondary stage of the linear motor; a second cavity is formed between the body assembly and the central pipe; the primary part of the linear motor is arranged in the first cavity, generates a magnetic field in a power-on state and drives the secondary part of the linear motor to move in the axial direction so as to drive the central pipe to move and further drive the valve body of the flat valve to rotate relative to the valve seat; a spring is arranged in the second cavity; and in a power-off state, the central tube is reset under the acting force of the spring. Risks caused by blockage of a control pipeline and a piston in a hydraulic system of a traditional hydraulic subsurface safety valve can be avoided.

Description

Technical Field

[0001] This invention relates to the field of oil and gas engineering technology, and in particular to an electric downhole safety valve and its usage method. Background Technology

[0002] A downhole safety valve is a tool used in oil and gas wells. It is a device that automatically shuts off the well when a major malfunction occurs at the wellhead. It serves to protect downhole equipment, prevent production losses, and prevent environmental pollution caused by oil and gas spills.

[0003] Currently used downhole safety valves are mainly hydraulic downhole safety valves. Under normal downhole operation conditions, hydraulic pressure is applied to the control line, pushing a piston to generate sufficient force to overcome the spring force, thus moving the flow tube downwards. This flow tube then opens the valve body of the flat plate valve, and the valve remains open by maintaining pressure within the control line. In the event of cessation of pressurization or a wellhead malfunction, the spring must overcome the hydraulic pressure to return the flat plate valve to its initial closed state. Existing downhole safety valves also include electro-hydraulic downhole safety valves and electric downhole safety valves. Electro-hydraulic downhole safety valves, when energized, utilize the expansion of hydraulic oil within the valve to move the flow tube, opening the valve. When closed, the spring force overcomes the hydraulic pressure to close it. Existing electric downhole safety valves primarily use a conversion mechanism to convert the motor's rotation into linear motion, which then moves the flow tube to open the valve. Summary of the Invention

[0004] The inventors have discovered that existing hydraulic and electro-hydraulic downhole safety valves have varying pressures due to the different hydraulic oil pressures at different downhole depths. Consequently, the pressure that the spring needs to overcome when the downhole safety valve is closed also varies. Therefore, downhole safety valves with springs of different specifications are required to suit different well depth requirements, increasing inventory costs. Furthermore, hydraulic downhole safety valves are controlled by hydraulic pipelines, which limits their insertion depth. Existing electric downhole safety valves require a helical drive mechanism to convert the motor's rotation into the linear motion of the flow tube, increasing structural complexity.

[0005] In view of the above problems, the present invention is proposed to provide an electric downhole safety valve and a method of using the same to overcome or at least partially solve the above problems.

[0006] This invention provides an electric downhole safety valve, comprising: a body assembly and an inner tube assembly and a flat plate valve disposed within the body assembly;

[0007] The flat plate valve includes: a valve body and a valve seat that are rotatably connected, the valve seat being connected to the main body assembly;

[0008] The inner tube assembly includes: a central tube, the secondary winding of the linear motor, and the primary winding of the linear motor;

[0009] Wherein, the secondary of the linear motor is a section of the central tube, or the secondary of the linear motor is connected to the central tube;

[0010] A first chamber is formed between the body assembly and the secondary winding of the linear motor; a second chamber is formed between the body assembly and the central tube;

[0011] The primary winding of the linear motor is disposed in the first chamber. When energized, it generates a magnetic field and drives the secondary winding of the linear motor to move axially, thereby driving the central tube to move and in turn driving the valve body to rotate relative to the valve seat.

[0012] A spring is installed in the second chamber; in the power-off state, the central tube is reset under the force of the spring.

[0013] In an optional embodiment, the primary of the linear motor includes: a stator core and a plurality of coils;

[0014] The stator core is fixed to the inner wall of the main body assembly;

[0015] The stator core has multiple inner slots on its inner wall, and the coils are sequentially arranged in the inner slots. The coils are connected to an external electrical control box to generate a magnetic field when energized.

[0016] In an optional embodiment, the secondary of the linear motor includes a mover core, and an air gap is formed between the mover core and the stator core, the air gap being parallel to the direction of movement of the secondary of the linear motor.

[0017] In an optional embodiment, the inner wall shape of the stator core is adapted to the outer wall shape of the mover core.

[0018] In an optional embodiment, the body assembly is provided with a cable hole for the cable to pass through the body assembly and connect to the primary of the linear motor.

[0019] In an optional embodiment, the body assembly includes a first connector, a housing, a second connector, and a third connector connected sequentially from top to bottom;

[0020] A first chamber is formed between the secondary winding of the linear motor, the first connector, and the housing; a second chamber is formed between the central tube, the housing, and the second connector.

[0021] The cable hole is located at the first connector; the valve seat is connected to the lower end of the second connector.

[0022] In an optional embodiment, the third connector is provided with a connector end face, the inner diameter of which is smaller than the outer diameter of the central tube;

[0023] A first protrusion is provided on the inner wall of the housing, and a second protrusion is provided on the central tube;

[0024] The central tube is axially limited by the cooperation of the first boss and the second boss or by the end face of the boss.

[0025] In an optional embodiment, one end of the spring is connected to the lower end face of the first boss of the central tube, and the other end of the spring is connected to the second connector via a bearing.

[0026] In an optional embodiment, the valve body and valve seat are connected by a pin, and a torsion spring is fitted on the pin.

[0027] Based on the same inventive concept, this invention also provides a method for using the above-mentioned electric downhole safety valve, characterized in that it includes:

[0028] When energized, the primary winding of the linear motor generates a magnetic field. Under the influence of the magnetic field, the secondary winding of the linear motor moves axially and drives the central tube to move axially, which in turn drives the valve body to rotate relative to the valve seat through the central tube.

[0029] When the power is off, the central tube moves under the restoring force of the spring to reset the valve body.

[0030] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0031] The electric downhole safety valve provided in this embodiment of the invention uses a linear motor whose primary motor generates a magnetic field when energized. This magnetic field interacts with the secondary motor, driving it to move axially. This, in turn, causes the central tube to move axially, which in turn causes the valve body of the flat valve to rotate relative to the valve seat. In other words, the downhole safety valve of this embodiment replaces the hydraulic plunger of a traditional downhole safety valve with a linear motor, avoiding the risks caused by blockages in the control lines and pistons of the hydraulic system, thus improving reliability. Furthermore, the downhole safety valve's insertion depth is not limited by the well depth. In the event of a malfunction requiring the flat valve body to reset, the spring does not need to overcome hydraulic pressure. Therefore, it eliminates the need for downhole safety valves with springs of different specifications depending on the insertion depth, reducing production and inventory costs. Additionally, the linear motor structure in this embodiment allows direct axial movement of the central tube when energized. Compared to traditional electric downhole safety valves, this eliminates the intermediate conversion mechanism that converts rotary motion into linear motion, resulting in advantages such as fast response, high sensitivity, and simple structure.

[0032] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0033] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0034] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0035] Figure 1 This is a schematic diagram of the flat valve of the electric downhole safety valve in the closed state in an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the flat valve of the electric downhole safety valve in the open state in an embodiment of the present invention;

[0037] Figure 3 This is a detailed structural diagram of the linear motor structure of the electric downhole safety valve when the stator core is cylindrical in an embodiment of the present invention;

[0038] Figure 4 This is a cross-sectional schematic diagram of the linear motor structure when the stator core is gear-type in an embodiment of the present invention.

[0039] Explanation of reference numerals in the attached figures:

[0040] 100-Electric downhole safety valve;

[0041] 10-First connector, 20-Housing, 30-Second connector, 40-Third connector, 50-Primary of linear motor, 60-Center tube; 70-Flat valve, 80-Bearing, 90-Spring;

[0042] 11-First female thread, 12-Cable hole, 13-First male thread, 21-First chamber, 22-Second chamber, 23-Second female thread, 24-Third female thread, 25-First boss, 31-Second male thread, 32-Third male thread, 33-Fourth male thread, 41-Fourth female thread, 42-Fifth male thread, 43-Connector end face, 61-Secondary of linear motor, 62-Flow tube, 63-Second boss, 64-Bottom end face of central tube, 71-Valve body, 72-Valve seat, 73-Pin, 74-Torsion spring, 75-Fifth female thread;

[0043] 501-Coil, 502-Stator core, 503-Groove, 612-Raised tooth, 611-Motor core. Detailed Implementation

[0044] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0045] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] The inventors have discovered that traditional hydraulic and electro-hydraulic downhole safety valves have varying pressures due to the different hydraulic oil pressures at different downhole depths. Consequently, the pressure the spring needs to overcome when the downhole safety valve closes also varies. Therefore, safety valves with springs of different specifications are required to suit different well depth requirements. Consequently, the size of the downhole safety valve will also differ when different spring specifications are used. This necessitates maintaining a large inventory of downhole safety valves to store and maintain multiple specifications, increasing inventory and maintenance costs. Furthermore, the opening of the flat plate valve of a traditional hydraulic downhole safety valve requires the introduction of hydraulic oil through a hydraulic pipeline, making the operation procedure complex. Therefore, the depth of insertion is limited by the hydraulic pipeline, and the hydraulic control response time is long with low sensitivity.

[0048] Existing electric downhole safety valves require a helical drive mechanism to convert the motor's rotation into the linear motion of the flow tube, increasing the complexity of the structure.

[0049] To address the problems existing in the prior art, embodiments of the present invention provide an electric downhole safety valve and its usage method.

[0050] The electric downhole safety valve 100 provided in this embodiment of the invention refers to... Figure 1 and Figure 2 As shown, it includes: a body assembly and an inner tube assembly and a flat plate valve 70 disposed within the body assembly;

[0051] The flat plate valve 70 includes a valve body 71 and a valve seat 72 rotatably connected, the valve seat 72 being connected to the body assembly;

[0052] The inner tube assembly includes: a central tube 60, a secondary tube 61 of the linear motor, and a primary tube 50 of the linear motor;

[0053] Wherein, the secondary 61 of the linear motor is a segment of the central tube 60, or the secondary 61 of the linear motor is connected to the central tube 60.

[0054] A first chamber 21 is formed between the main body assembly and the secondary winding 61 of the linear motor; a second chamber 22 is formed between the main body assembly and the central tube 60.

[0055] The primary 50 of the linear motor is located in the first chamber 21. When energized, it generates a magnetic field and drives the secondary of the linear motor to move axially, thereby driving the central tube 60 to move, and in turn driving the valve body 71 to rotate relative to the valve seat 72.

[0056] A spring 90 is installed in the second chamber 22; when the power is off, the central tube 60 is reset by the force of the spring 90.

[0057] The electric downhole safety valve 100 provided in this embodiment of the invention comprises a linear motor structure formed by the primary winding 50 and the secondary winding 61 of a linear motor. When energized, the primary winding 50 generates a magnetic field, which interacts with the secondary winding 61 to drive it to move axially, thereby causing the central tube 60 to move axially, and consequently causing the valve body 71 of the flat plate valve 70 to rotate relative to the valve seat 72. In other words, during the application of the downhole safety valve in this embodiment of the invention, the linear motor structure replaces the hydraulic plunger of a traditional downhole safety valve, avoiding the blockage of control lines and pistons in the hydraulic system that could cause wind. The safety valve is designed to be safe and reliable, as its insertion depth is not limited by the well depth. Furthermore, in the event of a malfunction requiring the valve body 71 of the flat valve 70 to reset, the spring 90 does not need to overcome hydraulic pressure. Therefore, it eliminates the need for downhole safety valves with springs of different specifications depending on the insertion depth, reducing production and inventory costs. Additionally, the downhole safety valve in this embodiment features a linear motor structure, which can directly drive the flow tube axially when energized. Compared to other electric downhole safety valves, it eliminates the intermediate conversion mechanism that converts rotary motion into linear motion, thus offering advantages such as fast response, high sensitivity, and simple structure.

[0058] In this embodiment, the secondary winding 61 of the linear motor is a section of the central tube 60, or the secondary winding 61 of the linear motor is connected to the central tube 60. That is, the central tube 60 and the secondary winding 61 of the linear motor can be integrally formed or can be separately processed and then connected together. This embodiment of the invention does not make specific limitations on this.

[0059] Optionally, with the secondary winding 61 of the linear motor being a segment of the central tube 60, refer to... Figure 1 As shown, the central tube 60 may include the secondary winding 61 of a linear motor and a flow tube 62. When energized, the axial movement of the secondary winding 61 of the linear motor drives the flow tube 62 to move axially. When the secondary winding 61 of the linear motor is connected to the central tube 60, for example, the secondary winding 61 of the linear motor can be connected to one end of the central tube 60, or the secondary winding 61 of the linear motor can be located between two sections of the central tube 60. The specific position of the secondary winding of the linear motor relative to the central tube 60 can be determined according to the design position of the linear motor structure in the downhole safety valve. This embodiment of the invention does not impose specific limitations on this.

[0060] Optionally, the primary 50 of the linear motor includes: a stator core 502 and multiple coils 501;

[0061] The stator core 502 is fixed to the inner wall of the main body assembly;

[0062] The stator core 502 has multiple inner slots on its inner wall. The coils 501 are arranged in the inner slots in sequence, and the coils are connected to the external electrical control box to generate a magnetic field when energized.

[0063] The secondary winding 61 of the linear motor includes a mover core 611, and an air gap is formed between the mover core 611 and the stator core 502. The air gap is parallel to the direction of movement of the secondary winding 61 of the linear motor.

[0064] Specifically, the basic working principle of the linear motor is as follows: When the coil 501 of the primary 50 of the linear motor is energized, a traveling wave magnetic field is generated in the air gap. The traveling wave magnetic field interacts with the secondary 61 of the linear motor to generate electromagnetic thrust, which drives the secondary 61 of the linear motor to move axially. The air gap between the moving core 611 and the stator core 502 can prevent direct contact between the stator core and the moving core, thereby reducing friction, wear and noise between the two when the moving core moves relative to the stator core.

[0065] It should be noted that, for the specific structure of the linear motor, such as the number of coils, the shape, length, and size of the stator core and the mover core, those skilled in the art can make selections according to specific needs, and the embodiments of the present invention do not impose specific limitations on this.

[0066] The present invention does not specifically limit the magnitude of the thrust generated by the linear motor in the downhole safety valve. As long as the linear motor can push the central tube to overcome the spring force and move downward when the downhole safety valve is energized, and can push the valve body of the flat plate valve to rotate relative to the valve seat during the downward movement of the central tube so that the flat plate valve is in the open state, the specific settings can be made according to actual needs.

[0067] Optionally, in the structure of the linear motor, the inner wall shape of the stator core 502 matches the outer wall shape of the mover core 611. Specifically, the inner wall of the stator core 502 can be cylindrical, gear-shaped, or other shapes, and the corresponding outer wall of the mover core 611 matches the inner wall of the stator core 502. That is, when the inner wall of the stator core is cylindrical, the inner wall of the mover core 611 is also cylindrical (see reference). Figure 3 (As shown); When the inner wall of the stator core 502 is gear-shaped, the inner wall of the mover core 611 is also gear-shaped (refer to...). Figure 4 (As shown).

[0068] In an optional embodiment, refer to Figure 4As shown, when the inner wall of the stator core 502 has a gear-shaped structure, the structure at the linear motor can be as follows: Multiple toothed grooves 503 are provided on the inner wall of the stator core 502; correspondingly, multiple protruding teeth 612 corresponding to the toothed grooves 503 are provided on the outer wall of the mover core 611. Setting the stator core 502 and the mover core 611 as a multi-tooth structure increases the coupling area between the stator core and the mover core, which is beneficial for increasing the thrust of the linear motor on the secondary winding 61 of the linear motor. The toothed grooves 503 on the stator core and the corresponding protruding teeth 612 have the same shape, such as trapezoidal or rectangular shapes; this embodiment of the invention does not specifically limit this.

[0069] Furthermore, the body assembly of the downhole safety valve is provided with a cable hole 12 for the cable to pass through the body assembly and connect to the primary 50 of the linear motor.

[0070] Specifically, the energization and de-energization status of the primary 50 of the linear motor is controlled by an electrical control box located at the wellhead. A cable with one end connected to the electrical control box passes through the cable hole 12 on the main body assembly and connects to the primary 50 of the linear motor to realize the connection between the electrical control box and the primary 50 of the linear motor.

[0071] In an optional embodiment, the body assembly includes a first connector 10, a housing 20, a second connector 30, and a third connector 40 connected sequentially from top to bottom;

[0072] A first chamber 21 is formed between the secondary winding 61 of the linear motor, the first connector 10 and the housing 30, and a second chamber 22 is formed between the central tube 60, the housing 20 and the second connector 30.

[0073] Cable hole 12 is provided on the first connector 10; valve seat 72 is connected to the lower end of the second connector 30.

[0074] Specifically, refer to Figure 1 and Figure 2 As shown, the connection relationship between the first connector 10, the housing 20, the second connector 30, and the third connector 40 can be as follows: the upper end of the first connector 10 is provided with a first female thread 11, and the lower end is provided with a first male thread 13; the upper end of the housing 20 is provided with a second female thread 23, and the lower end is provided with a third female thread 24; the upper end of the second connector 30 is provided with a second male thread 31, and the lower end is provided with a third male thread 32 and a fourth male thread 33; the upper end of the third connector 40 is provided with a fourth female thread 41, and the lower end is provided with a fifth male thread 42.

[0075] The first connector 10 is connected to the casing of the first downhole safety valve via the first female thread 11; the housing 20 is connected to the first connector 10 via the second female thread 23 and the first male thread 13; the housing 20 is connected to the second connector 30 via the second male thread 31 and the third female thread 24; the third connector 40 is connected to the second connector 30 via the fourth female thread 41 and the third male thread 32; and the third connector 40 is connected to the casing of the third downhole safety valve via the fourth male thread 42.

[0076] Furthermore, a fifth female thread 75 is provided on the valve seat 72 of the flat plate valve 70, which is connected to the fourth male thread 42, so as to realize the connection between the valve seat 72 of the flat plate valve 70 and the second connector 30.

[0077] In an optional embodiment, the electric downhole safety valve of this invention has a third connector 40 with a connector end face 43; the inner diameter of the connector end face 43 is smaller than the outer diameter of the central tube 60.

[0078] The inner wall of the housing is provided with a first protrusion 25, and the central tube 60 is provided with a second protrusion 63;

[0079] The central tube 60 can be axially limited by the cooperation of the first boss 25 and the second boss 63, or by the end face 43 of the boss.

[0080] Specifically, refer to Figure 1 As shown, when the electric downhole safety valve 100 is in its initial state, the initial state described in this embodiment refers to the flat valve 70 inside the electric downhole safety valve being in a closed state. At this time, under the action of the spring 90, the lower end face of the first boss 25 abuts against the upper end face of the second boss 63 to axially position the central tube 60, keeping the central tube 60 in its initial position. In the energized state, the secondary winding 61 of the linear motor moves downward, generating an axial thrust, pushing the central tube 60 downward and compressing the spring 90. The bottom end face 64 of the central tube 60 pushes open the valve body 71 of the flat valve 70, causing the valve body 71 of the flat valve 70 to rotate relative to the valve seat 72 until the bottom end face 64 of the central tube 60 contacts the connector end face 43, at which point the downward movement stops. That is, the connector end face 43 is used to axially position the central tube 60 during its downward movement. Figure 2 As shown.

[0081] In an optional embodiment, one end of the spring 90 is connected to the lower end face of the first boss 25 of the central tube 60, and the other end of the spring 90 is connected to the second connector 30 through the bearing 80. Since the spring 90 located in the second chamber 22 will be compressed during the downward movement of the central tube 60 driven by the secondary 61 of the linear motor, a certain torsional force will be generated during the compression of the spring 90. Therefore, the setting of the rotating shaft can alleviate the torsional force of the spring 90 to a certain extent and prevent the central tube 60 from rotating during the downward movement.

[0082] In an optional embodiment, the valve body 71 and the valve seat 72 are connected by a pin 73, and a torsion spring 74 is sleeved on the pin 73. When the downhole safety valve is in its initial state, the flat plate valve 70 is in the closed state under the action of the torsion spring 74. When the secondary 61 of the linear motor drives the central tube 60 to move and open the valve body 71 of the flat plate valve 70, the valve body 71 of the flat plate valve 70 rotates around the pin 73 and compresses the torsion spring 74. During the upward movement of the central tube 60, the valve body 71 is reset under the force of the torsion spring 74, so that the downhole safety valve is in the closed state.

[0083] Reference Figure 1 and Figure 2 As shown, the working process of the electric downhole safety valve in this embodiment of the invention is illustrated below: The primary 50 of the linear motor is energized, driving the secondary 61 of the linear motor to move downward, generating axial thrust to push the central tube 60 downward and compress the spring 90. The bottom end face 64 of the central tube pushes open the valve body 71 of the flat plate valve 70, causing the valve body 71 of the flat plate valve 70 to rotate around the pin 73 until the bottom end face 64 of the central tube fits against the end face 43 of the connector, so that the flat plate valve 70 is in the open state.

[0084] When it is necessary to close the electric downhole safety valve 100, the current can be switched through the control box to drive the secondary 61 of the linear motor to move upward. Under the combined action of the linear motor and the spring 90, the central tube 60 moves upward until the upper end face of the second protrusion 63 of the central tube 60 contacts the lower end face of the first protrusion 25 of the housing 20. At this time, the central tube 60 is in the upper position, and the flat plate valve 70 is closed under the action of the torsion spring 74.

[0085] When the electric downhole safety valve 100 malfunctions and suddenly loses power, the central tube 60 can move upward under the action of the spring 90, and the flat valve 70 closes under the action of the torsion spring 74, thus realizing the automatic closure of the electric downhole safety valve 100 when power is lost.

[0086] The electric downhole safety valve provided in this invention replaces the hydraulic plunger with a linear motor, avoiding the risks caused by blockage of the control lines and pistons in the hydraulic system and improving reliability; moreover, the downhole safety valve is no longer limited by the well depth, adapting to various working conditions and occasions.

[0087] Furthermore, this electric downhole safety valve directly drives the axial movement of the central tube through the structure of a linear motor. Compared with traditional electric downhole safety valves, it eliminates the intermediate conversion mechanism that converts rotary motion into linear motion, thereby increasing the response speed and sensitivity of the downhole safety valve. Moreover, its simple structure reduces the overall size of the device, making it more suitable for the limited working space downhole and saving manufacturing costs.

[0088] Furthermore, the primary setting of the linear motor of this electric downhole safety valve, together with the secondary winding of the linear motor, the first connector, and the intermediate housing, forms a first chamber with strong sealing performance. This prevents downhole liquids from entering the first chamber and causing contamination, thus affecting downhole safety. This makes it more suitable for downhole working environments.

[0089] Based on the same inventive concept, embodiments of the present invention also provide a method for using the above-mentioned electric downhole safety valve, including:

[0090] When energized, the primary winding of the linear motor generates a magnetic field. Under the influence of the magnetic field, the secondary winding of the linear motor moves axially and drives the central tube to move axially, which in turn drives the valve body to rotate relative to the valve seat through the central tube.

[0091] When the power is off, the central tube moves under the restoring force of the spring to reset the valve body.

[0092] Specifically, when the power is on, the rotation of the valve body relative to the valve seat caused by the central tube includes: when the secondary of the linear motor moves downward along its axis, the valve body rotates relative to the valve seat to open the flat valve; or when the secondary of the linear motor moves upward along its axis, the valve body rotates relative to the valve seat to close the flat valve.

[0093] Regarding the method of using the electric downhole safety valve in the above embodiments, the specific way in which each module performs its operation has been described in detail in the embodiments of the above device, and will not be elaborated here.

[0094] Based on the same inventive concept, this invention also provides an application of the above-mentioned electric downhole safety valve in the field of oil and gas engineering technology.

[0095] The electric downhole safety valve provided in this invention is applicable to the field of oil and gas engineering technology, and can be specifically applied to well completion operations in oil and gas wells. The downhole safety valve is lowered into a preset position in the well along with the casing connected to it. During normal well completion operations in oil and gas wells, the downhole safety valve is in the open state when energized, without affecting the normal downhole operation process. When a fault occurs at the wellhead and a sudden power outage occurs, the thrust of the linear motor disappears, and the central tube can move upward under the action of the spring. During the upward movement of the central tube, the valve body of the flat plate valve rotates relative to the valve seat along the rotating shaft under the action of the torsion spring, so that the downhole safety valve is in the closed state, that is, the function of automatic closing of the electric downhole safety valve in the event of a power outage is realized.

[0096] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

[0097] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of the invention.

[0098] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as interpreted when used as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

Claims

1. An electric downhole safety valve, characterized in that: include: A body component, an inner tube component and a flat valve arranged in the body component; The flat plate valve comprises: a valve body and a valve seat which are rotatably connected, wherein the valve seat is connected to the body assembly; The inner tube assembly includes: a central tube, a secondary of a linear motor and a primary of a linear motor; Wherein, the secondary of the linear motor is a section in the central tube, or the secondary of the linear motor is connected to the central tube; A first chamber is formed between the body component and the secondary of the linear motor; a second chamber is formed between the body component and the central tube; The primary of the linear motor is arranged in the first chamber, generates a magnetic field when powered on and drives the secondary of the linear motor to move axially, so as to drive the central tube to move, and further drive the valve body to rotate relative to the valve seat; A spring is arranged in the second chamber; in a power-off state, the central tube is reset under the action force of the spring.

2. The electric downhole safety valve according to claim 1, characterized in that: The primary of the linear motor includes: a stator core and a plurality of coils; The stator core is fixed on the inner wall of the body component; A plurality of inner grooves are arranged on the inner wall of the stator core, the coils are arranged in the inner grooves in sequence, and the coils are connected to an external electric control box to generate a magnetic field when powered on.

3. The electric downhole safety valve according to claim 2, characterized in that: The secondary of the linear motor includes: a mover core, and an air gap is formed between the mover core and the stator core, and the air gap is parallel to the direction of secondary movement of the linear motor.

4. The electric downhole safety valve according to claim 3, characterized in that: The shape of the inner wall of the stator core is matched with the shape of the outer wall of the mover core.

5. The electric downhole safety valve according to claim 1, characterized in that: The body component is provided with a cable hole for the cable to pass through the body component and be connected to the primary of the linear motor.

6. The electric downhole safety valve according to claim 5, characterized in that: The body assembly includes a first joint, a shell, a second joint and a third joint connected in sequence from top to bottom; A first chamber is formed between the secondary of the linear motor, the first joint and the housing, and a second chamber is formed between the central tube, the housing and the second joint; The cable hole is arranged on the first joint; the valve seat is connected to the lower end of the second joint.

7. The electric downhole safety valve according to claim 6, characterized in that: The third joint is provided with a joint end face, and the inner diameter of the joint end face is smaller than the outer diameter of the central tube; A first boss is provided on the inner wall of the shell, and a second boss is provided on the central tube; The center tube is axially limited by the cooperation between the first boss and the second boss, or by the end surface of the boss.

8. The electric downhole safety valve according to claim 7, characterized in that: One end of the spring is connected to the lower end surface of the first boss of the central tube, and the other end of the spring is connected to the second joint through a bearing.

9. The electric downhole safety valve according to any one of claims 1 to 8, characterized in that: The valve body and the valve seat are connected via a pin shaft, and a torsion spring is sleeved on the pin shaft.

10. A method for using the electric downhole safety valve according to any one of claims 1 to 9, characterized in that: include: When powered on, the primary of the linear motor generates a magnetic field, and the secondary of the linear motor moves axially under the action of the magnetic field and drives the central tube to move axially, thereby driving the valve body to rotate relative to the valve seat through the central tube; In a power-off state, the central tube moves under the restoring force of the spring to reset the valve body.

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