Detection tool and detection method for pressure-limiting flow controller for well cementation

Abstract

The invention relates to the technical field of petroleum well cementation, in particular to a detection tool and method for a pressure limiting flow controller for well cementation. According to the detection tool and method, a shaft simulation assembly is connected with the output end of the pressure limiting flow controller for well cementation, and the pressure of fluid in a shaft on the pressure limiting flow controller for well cementation can be simulated; the driving assembly is connected with the input end of the pressure limiting and flow controlling device for well cementation, fluid can be injected into the pressure limiting and flow controlling device for well cementation, and the problem that at present, a tool and a method for detecting the piston opening pressure and the safety pressure of the pressure limiting and flow controlling device for well cementation are lacked can be solved. The working state of the pressure limiting and flow controlling device for well cementation can be simulated on the ground, the piston opening pressure and the safety pressure of the pressure limiting and flow controlling device for well cementation are detected on the ground, and it is ensured that setting of the piston opening pressure and the safety pressure of the pressure limiting and flow controlling device for well cementation meets the requirements.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum cementing, and in particular to a detection tool and a detection method for a pressure limiting flow controller for cementing. Background Art

[0002] Cementing is the operation of inserting casing into the well and injecting cement into the annular space between the wellbore and the casing. It is an indispensable and important part of the drilling and completion process, which includes casing installation and cement injection. Cementing technology is characterized by systematic, one-time and short time. The main purpose of cementing is to protect and support the casing in the oil and gas well, and to isolate the oil, gas and water formations.

[0003] During the cementing process, a cementing pressure limiting flow controller can be used to overcome the U-tube effect that occurs during the cementing process. Before the cementing pressure limiting flow controller is used for cementing, the piston opening pressure and safety pressure of the cementing pressure limiting flow controller need to be adjusted. Only after the adjustment is completed can it be used in the cementing process. However, there is currently a lack of detection tooling and detection methods for the piston opening pressure and safety pressure of the cementing pressure limiting flow controller, and it is impossible to ensure that the piston opening pressure and safety pressure settings of the cementing pressure limiting flow controller meet the requirements. Summary of the invention

[0004] The embodiments of the present invention provide a detection tooling and detection method for a pressure limiting flow controller for cementing, which can solve the problem that there is currently a lack of detection tooling and detection method for the piston opening pressure and safety pressure of the pressure limiting flow controller for cementing, and it is impossible to ensure that the settings of the piston opening pressure and safety pressure of the pressure limiting flow controller for cementing meet the requirements.

[0005] In a first aspect, an embodiment of the present invention provides a pressure limiting flow controller detection tool for cementing, comprising:

[0006] A wellbore simulation component, connected to the output end of the cementing pressure limiting flow controller, for simulating the pressure of the wellbore fluid on the cementing pressure limiting flow controller;

[0007] The driving assembly is connected to the input end of the pressure limiting flow controller for cementing and is used to inject fluid into the pressure limiting flow controller for cementing.

[0008] In one embodiment, the wellbore simulation component includes: a wellbore pressure pump; a wellbore connection structure, one end of which is connected to the wellbore pressure pump and the other end is connected to the output end of the cementing pressure limiting flow controller; a wellbore pressure gauge, which is arranged on the wellbore connection structure or the wellbore pressure pump.

[0009] In one embodiment, the driving assembly includes: a driving pressure pump; a driving connection structure, one end of which is connected to the driving pressure pump and the other end is connected to the input end of the cementing pressure limiting flow controller; and a driving pressure gauge, which is arranged on the driving connection structure or the driving pressure pump.

[0010] In a second aspect, an embodiment of the present invention provides a method for detecting a pressure limiting flow controller for cementing, comprising:

[0011] Setting the pressure limiting structure detection data of the pressure limiting flow controller for cementing, wherein the pressure limiting structure detection data includes the normal piston opening pressure of the variable cross-section pressure limiting structure of the pressure limiting flow controller for cementing and the normal safety pressure of the safety opening structure of the pressure limiting flow controller for cementing;

[0012] Connecting the output end of the cementing pressure limiting flow controller to the wellbore simulation component;

[0013] Connecting the input end of the cementing pressure limiting flow controller to the driving assembly;

[0014] The normal piston opening pressure of the variable-section pressure-limiting structure of the pressure-limiting flow controller for cementing is detected by the wellbore simulation component and the drive component.

[0015] In one embodiment, the pressure limiting structure detection data of the pressure limiting flow controller for cementing is set, wherein the pressure limiting structure detection data includes the normal piston opening pressure of the variable-section pressure limiting structure of the pressure limiting flow controller for cementing and the normal safety pressure of the safety opening structure of the pressure limiting flow controller for cementing, including: adjusting the cross-sectional area of ​​the upper end of the variable-diameter piston of the variable-section pressure limiting structure, and / or the cross-sectional area of ​​the lower end of the variable-diameter piston to set the normal piston opening pressure; adjusting the specifications of the shear pins of the safety opening structure to set the normal safety pressure; wherein the normal safety pressure is greater than the normal piston opening pressure.

[0016] In one embodiment, the output end of the pressure limiting flow controller for cementing is connected to the wellbore simulation component, specifically: the output end of the pressure limiting flow controller for cementing is connected to the wellbore pressure pump through a wellbore connection structure; the input end of the pressure limiting flow controller for cementing is connected to the drive component, specifically: the input end of the pressure limiting flow controller for cementing is connected to the drive pressure pump through a drive connection structure.

[0017] In one embodiment, the normal piston opening pressure of the variable-section pressure limiting structure of the cementing pressure limiting flow controller is detected by the wellbore simulation component and the drive component, specifically: the wellbore pressure pump of the wellbore simulation component is turned on, and the pressure at the output end of the cementing pressure limiting flow controller is increased to the simulated well depth pressure; the drive pressure pump of the drive component is turned on, and the pressure at the input end of the cementing pressure limiting flow controller is increased to the normal piston opening pressure; if the variable diameter piston of the variable-section pressure limiting structure moves to the piston opening position, and the opening sleeve of the safety opening structure has not moved to the safety opening position, then the normal piston opening pressure setting is qualified.

[0018] In one embodiment, the method for detecting a pressure limiting flow controller for cementing further includes:

[0019] The safety structure detection data of the pressure limiting flow controller for cementing is set, wherein the safety structure detection data includes the abnormal piston opening pressure of the variable-section pressure limiting structure of the pressure limiting flow controller for cementing and the abnormal safety pressure of the safety opening structure of the pressure limiting flow controller for cementing; the abnormal safety pressure of the safety opening structure of the pressure limiting flow controller for cementing is detected by the wellbore simulation component and the drive component.

[0020] In one embodiment, the safety structure detection data of the pressure limiting flow controller for cementing is set, wherein the safety structure detection data includes the abnormal piston opening pressure of the variable-section pressure limiting structure of the pressure limiting flow controller for cementing and the abnormal safety pressure of the safety opening structure of the pressure limiting flow controller for cementing, specifically: adjusting the cross-sectional area of ​​the upper end of the variable-diameter piston of the variable-section pressure limiting structure, and / or the cross-sectional area of ​​the lower end of the variable-diameter piston to set the abnormal piston opening pressure; adjusting the specifications of the shear pins of the safety opening structure to set the abnormal safety pressure; wherein the abnormal safety pressure is less than the abnormal piston opening pressure.

[0021] In one embodiment, the abnormal safety pressure of the safety opening structure of the pressure limiting flow controller for cementing is detected by the wellbore simulation component and the drive component, specifically: the wellbore pressure pump of the wellbore simulation component is turned on, and the pressure at the output end of the pressure limiting flow controller for cementing is increased to the simulated well depth pressure; the drive pressure pump of the drive component is turned on, and the pressure at the input end of the pressure limiting flow controller for cementing is increased to the abnormal piston opening pressure; if the opening sleeve of the safety opening structure moves to the safe opening position, and the variable diameter piston of the variable cross-section pressure limiting structure has not moved to the piston opening position, then the abnormal safety pressure setting is qualified.

[0022] Compared with the prior art, the embodiment of the present invention can simulate the pressure of the fluid in the wellbore on the pressure limiting flow controller for cementing by connecting the wellbore simulation component to the output end of the pressure limiting flow controller for cementing; and can inject fluid into the pressure limiting flow controller for cementing by connecting the driving component to the input end of the pressure limiting flow controller for cementing, which can solve the problem of the current lack of detection tooling and detection method for the piston opening pressure and safety pressure of the pressure limiting flow controller for cementing, and can simulate the working state of the pressure limiting flow controller for cementing on the ground, and detect the piston opening pressure and safety pressure of the pressure limiting flow controller for cementing on the ground, to ensure that the settings of the piston opening pressure and safety pressure of the pressure limiting flow controller for cementing meet the requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the accompanying drawings.

[0024] Figure 1 It is a schematic diagram of the structure of a pressure limiting flow controller for cementing provided by an embodiment of the present invention;

[0025] Figure 2 It is a schematic diagram of the structure of a pressure limiting flow controller detection tooling for cementing provided by an embodiment of the present invention;

[0026] Figure 3 The present invention is a flow chart of a method for detecting a pressure limiting flow controller for cementing provided in one embodiment of the present invention.

[0027] Reference numerals:

[0028] 1. Pressure limiting flow controller for cementing;

[0029] 10. Connection structure; 110. Variable buckle joint; 120. Upper joint; 130. Casing short-circuit; 140. Casing coupling;

[0030] 20, core tube assembly; 210, center tube; 2101, pressure limiting flow control hole; 2102, safety opening hole; 220, thread plug;

[0031] 30. wall tube assembly; 310. outer wall tube; 320. short sleeve;

[0032] 40. Pressure limiting and flow control assembly; 410. Variable diameter hydraulic cylinder; 4101. Pressure limiting connecting hole; 4102. External pressure connecting hole; 420. Variable cross-section pressure limiting structure; 4201. Variable diameter piston; 4202. Reset member; 4203. Fixed seat; 42031. Mounting groove;

[0033] 50. Safety opening structure; 510. Opening sleeve; 520. Shear nail;

[0034] 2. Wellbore simulation component; 201. Wellbore pressure pump; 202. Wellbore connection structure; 2021. Wellbore pressure joint; 2022. Wellbore connection cap;

[0035] 3. Driving assembly; 301. Driving pressure pump; 302. Driving connection structure; 3021. Driving pressure joint; 3022. Driving connection cap. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings.

[0037] Cementing is the operation of inserting casing into the well and injecting cement into the annular space between the wellbore and the casing. It is an indispensable and important link in the drilling and completion process, which includes casing installation and cement injection. Cementing technology is a multidisciplinary comprehensive application technology with the characteristics of systematic, one-time and short time. The main purpose of cementing is to protect and support the casing in the oil and gas well, and to isolate the oil, gas and water formations.

[0038] During the cementing process, a pressure limiting flow controller for cementing can be used to overcome the U-tube effect that occurs during the cementing process. Before the pressure limiting flow controller for cementing is used for cementing, the piston opening pressure and safety pressure of the pressure limiting flow controller for cementing need to be adjusted. Only after the adjustment is completed can it be used in the cementing process. If the pressure limiting flow controller for cementing is not subjected to a ground simulation test, the following hazards will be brought to the cementing construction: 1) The structural design of the pressure limiting flow controller for cementing is unreasonable, and the reducer piston of the pressure limiting flow controller for cementing cannot work normally, so that the circulation cannot be established between the cementing tool and the well wall; 2) The parameter setting of the reducer piston of the pressure limiting flow controller for cementing is unreasonable, and the purpose of overcoming the U-tube effect cannot be achieved; 3) The safety pressure of the opening sleeve of the pressure limiting flow controller for cementing is less than the piston opening pressure of the reducer piston, and the purpose of overcoming the U-tube effect cannot be achieved; 4) The piston opening pressure of the reducer piston of the pressure limiting flow controller for cementing is too much greater than the safety pressure of the opening sleeve, which will cause a higher displacement pressure in the later stage of displacing cement slurry.

[0039] First, as Figure 2 As shown, in view of the above technical problems, an embodiment of the present invention provides a detection tool for a pressure limiting flow controller 1 for cementing, comprising:

[0040] The wellbore simulation component 2 is connected to the output end of the pressure limiting flow controller 1 for cementing, and is used to simulate the pressure of the fluid in the wellbore on the pressure limiting flow controller 1 for cementing;

[0041] The driving assembly 3 is connected to the input end of the pressure limiting flow controller 1 for cementing, and is used to inject fluid into the pressure limiting flow controller 1 for cementing.

[0042] It should be noted that when carrying out the cementing process, the cementing tool needs to be pushed deep into the wellbore. At this time, the liquid in the wellbore will generate pressure on the cementing tool. The pressure generated by the fluid in the wellbore on the cementing tool varies with the depth. When designing the cementing tool, it is necessary to set the opening pressure of the cementing tool according to the depth of the wellbore, so that when the preset pressure difference is met, the cementing pressure limiting flow controller 1 can be opened, so as to eliminate the U-tube effect generated during the cementing process. In this way, it is necessary to ensure that the cementing pressure limiting flow controller 1 can be opened at the preset pressure difference. Therefore, it is necessary to test the cementing pressure limiting flow controller 1 on the ground, wherein the cementing pressure limiting flow controller 1 is a device on the cementing tool for controlling the on and off of the cementing tool.

[0043] It should be noted that the wellbore simulation component 2 and the driving component 3 are usually located on opposite sides, that is, Figure 2 On the left and right sides, the wellbore simulation component 2 and the driving component 3 usually use water as the fluid to pressurize the output end of the cementing pressure limiting flow controller 1 and the input end of the cementing pressure limiting flow controller 1 respectively.

[0044] In some embodiments, the wellbore simulation component 2 includes: a wellbore pressure pump 201; a wellbore connection structure 202, one end of which is connected to the wellbore pressure pump 201, and the other end is connected to the output end of the pressure limiting flow controller 1 for cementing; a wellbore pressure gauge, which is arranged on the wellbore connection structure 202 or the wellbore pressure pump 201.

[0045] It should be noted that the wellbore pressure pump 201 is used to pump clean water of a certain pressure into the output end of the pressure limiting flow controller 1 for cementing. The wellbore pressure pump 201 is connected to the wellbore connection structure 202 through a pipeline. The wellbore connection structure 202 may include a wellbore connection cap 2022 and a wellbore pressure joint 2021. One end of the wellbore connection cap 2022 is connected to the pipeline, and the other end of the wellbore connection cap 2022 is connected to the wellbore pressure joint 2021. The wellbore pressure joint 2021 is connected to the output end of the pressure limiting flow controller 1 for cementing. The specific structure and form of the wellbore pressure joint 2021 can be adjusted according to the structure of the output end of the pressure limiting flow controller 1 for cementing.

[0046] In some embodiments, the driving component 3 includes: a driving pressure pump 301; a driving connection structure 302, one end of which is connected to the driving pressure pump 301, and the other end is connected to the input end of the pressure limiting flow controller 1 for cementing; and a driving pressure gauge, which is arranged on the driving connection structure 302 or the driving pressure pump 301.

[0047] It should be noted that the driving pressure pump 301 is used to pump clean water of a certain pressure into the input end of the pressure limiting flow controller 1 for cementing. The driving pressure pump 301 is connected to the driving connection structure 302 through a pipeline. The driving connection structure 302 may include a driving connection cap 3022 and a driving pressure joint 3021. One end of the driving connection cap 3022 is connected to the pipeline, and the other end of the driving connection cap 3022 is connected to the driving pressure joint 3021. The driving pressure joint 3021 is connected to the input end of the pressure limiting flow controller 1 for cementing. The specific structure and form of the driving pressure joint 3021 can be adjusted according to the structure of the input end of the pressure limiting flow controller 1 for cementing.

[0048] It should be noted that the wellbore simulation component 2 may also include a wellbore sensor, which is used to detect the displacement of the opening sleeve of the safety opening structure of the pressure limiting flow controller 1 for cementing. The driving component 3 may also include a driving sensor, which is used to detect the displacement of the variable diameter piston of the variable cross-section pressure limiting structure of the pressure limiting flow controller 1 for cementing.

[0049] It should be noted that if Figure 1 As shown, the pressure limiting flow controller 1 for cementing comprises:

[0050] A connection structure 10 having an inner connection end, a middle connection end and an outer connection end;

[0051] A core tube assembly 20 connected to the inner connection end;

[0052] The wall tube assembly 30 is connected to the external connection end;

[0053] The pressure limiting and flow control component 40 includes a variable diameter hydraulic cylinder 410 and a variable cross-section pressure limiting structure 420. The variable diameter hydraulic cylinder 410 is connected to the middle connecting end. The variable cross-section pressure limiting structure 420 is arranged between the core tube component 20 and the variable diameter hydraulic cylinder 410. The upper end of the variable cross-section pressure limiting structure 420 is connected to the core tube component 20, and the lower end of the variable cross-section pressure limiting structure 420 is connected to the wall tube component 30. The variable diameter hydraulic cylinder 410 is connected to the wall tube component 30 between the upper end of the variable cross-section pressure limiting structure 420 and the lower end of the variable cross-section pressure limiting structure 420.

[0054] Among them, the cross-sectional area of ​​the upper end of the variable-section pressure-limiting structure 420 is smaller than the cross-sectional area of ​​the lower end of the variable-section pressure-limiting structure 420, so that when the pressure difference between the upper end of the variable-section pressure-limiting structure 420 and the lower end of the variable-section pressure-limiting structure 420 reaches a preset pressure difference, the variable-section pressure-limiting structure 420 is pushed downward to connect the core tube assembly 20 with the wall tube assembly 30.

[0055] It should be noted that the upper end of the connecting structure 10 is used to be connected to the floating hoop, the inner connecting section, the middle connecting end and the outer connecting end are all located at the lower end of the connecting structure 10, and the inner connecting end, the middle connecting end and the outer connecting end are arranged in sequence from the inside to the outside. The core tube assembly 20 is usually in the shape of a circular tube, the wall tube assembly 30 is usually in the shape of a circular tube, and the variable diameter liquid cylinder 410 is a variable diameter cylinder body with an upper end diameter smaller than a lower end diameter. By connecting the core tube assembly 20 with the inner connecting end, connecting the wall tube assembly 30 with the outer connecting end, and connecting the variable diameter liquid cylinder 410 with the middle connecting end, a accommodating cavity with a smaller upper end and a larger lower end can be formed between the core tube assembly 20 and the variable diameter liquid cylinder 410, and an accommodating cavity is formed between the variable diameter liquid cylinder 410 and the wall tube assembly 30, wherein the variable cross-section pressure limiting structure 420 is arranged in the accommodating cavity between the core tube assembly 20 and the variable diameter liquid cylinder 410.

[0056] In some embodiments, the variable cross-section pressure limiting structure 420 includes a variable diameter piston 4201, a reset member 4202 and a fixed seat 4203; the upper end of the reset member 4202 is connected to the lower end of the variable diameter piston 4201, and the lower end of the reset member 4202 is connected to the fixed seat 4203, and the fixed seat 4203 is arranged between the core tube assembly 20 and the variable diameter cylinder 410, wherein the cross-sectional area of ​​the upper end of the variable diameter piston 4201 is smaller than the cross-sectional area of ​​the lower end of the variable diameter piston 4201.

[0057] It should be noted that the variable-section pressure-limiting structure 420 may only include a variable-diameter piston 4201, the area of ​​the upper section of the variable-diameter piston 4201 is smaller than the area of ​​the lower section of the variable-diameter piston 4201, and the variable-diameter piston 4201 may be fixed to the core tube assembly 20 by pins, etc. When the pressure difference between the pressure of the upper section of the variable-diameter piston 4201 and the pressure of the lower section of the variable-diameter piston 4201 reaches a preset pressure difference, the pin is cut off and the variable-diameter piston 4201 is pushed downward, so that the core tube assembly 20 is connected to the wall tube assembly 30.

[0058] It should be noted that the shape of the variable diameter piston 4201 matches the shape of the variable diameter cylinder 410. The variable diameter piston 4201 is slidably disposed in the accommodating cavity between the core tube assembly 20 and the variable diameter cylinder 410, and can slide freely in the accommodating cavity between the core tube assembly 20 and the variable diameter cylinder 410. The fixed seat 4203 is fixedly connected to the core tube assembly 20, and the reset member 4202 is used to provide an upward reset force for the variable diameter piston 4201 after the variable diameter piston 4201 moves downward, so that the variable diameter piston 4201 returns to its initial position.

[0059] It should be noted that sealing rings are provided on the inner side and the outer side of the variable diameter piston 4201 to ensure good sealing between the variable diameter piston 4201 and the core tube assembly 20 and the variable diameter liquid cylinder 410; a sealing ring is provided between the fixed seat 4203 and the core tube assembly 20 to ensure good sealing between the fixed seat 4203 and the core tube assembly 20, and multiple sealing rings can be set at the same sealing position according to actual needs, such as 2, 3, etc.

[0060] It should be noted that the preset pressure difference can be determined based on the depth of cementing, the density of the fluid, etc. After determining the preset pressure difference, the sizes of the variable diameter cylinder 410 and the variable diameter piston 4201 can be adjusted so that when the preset pressure difference is reached, the variable diameter piston 4201 is pushed downward to connect the core tube assembly 20 with the wall tube assembly 30, and then the fluid in the core tube assembly 20 can flow into the annulus through the accommodating cavity between the variable diameter cylinder 410 and the wall tube assembly 30, that is, when the preset pressure difference is large, the difference between the cross-sectional area of ​​the upper end of the variable diameter piston 4201 and the cross-sectional area of ​​the lower end of the variable diameter piston 4201 is large; when the preset pressure difference is small, the difference between the cross-sectional area of ​​the upper end of the variable diameter piston 4201 and the cross-sectional area of ​​the lower end of the variable diameter piston 4201 is small.

[0061] In some embodiments, a mounting groove 42031 is provided at the lower end of the fixing seat 4203; the pressure limiting flow controller 1 for cementing also includes a safe opening structure 50, the safe opening structure 50 includes an opening sleeve 510 and a shear nail 520, the opening sleeve 510 is fixed on the core tube assembly 20 by the shear nail 520, wherein the upper end of the opening sleeve 510 is provided in the mounting groove 42031, and the upper end of the opening sleeve 510 is communicated with the core tube assembly 20.

[0062] It should be noted that in order to prevent the variable cross-section pressure limiting structure 420 from being unable to open normally due to reasons such as jamming, a safety opening structure 50 can be provided to connect the core tube assembly 20 and the wall tube assembly 30 through the safety opening structure 50 when the variable cross-section pressure limiting structure 420 cannot be opened normally, that is, when the variable cross-section pressure limiting structure 420 is operating normally, when the pressure difference between the upper end of the variable diameter piston 4201 and the lower end of the variable diameter piston 4201 reaches a preset pressure difference, the core tube assembly 20 and the wall tube assembly 30 are connected by pushing the variable diameter piston 4201 downward. The tube assembly 30 is connected; when the variable-section pressure-limiting structure 420 cannot work normally, when the pressure at the upper end of the opening sleeve 510 reaches a preset pressure threshold, the fluid in the core tube assembly 20 pushes the opening sleeve 510 downward and cuts the shear pin 520, so that the core tube assembly 20 is connected with the wall tube assembly 30, thereby establishing a flow channel for the fluid, wherein the mounting groove 42031 and the upper end of the opening sleeve 510 can be sealed to ensure that the opening sleeve 510 and the mounting groove 42031 are well sealed when the opening sleeve 510 is not opened.

[0063] In some embodiments, the core tube assembly 20 includes: a central tube 210, a pressure limiting flow control hole 2101 is provided on the upper side, and a safety opening hole 2102 is provided on the lower side, the pressure limiting flow control hole 2101 is connected to the upper side of the pressure limiting flow control assembly 40, and the safety opening hole 2102 is connected to the upper side of the opening sleeve 510; a wire plug 220 is connected to the lower end of the central tube 210.

[0064] It should be noted that the pressure-limiting flow-control hole 2101 is located above the variable-diameter piston 4201 so that the fluid in the center tube 210 can be pressed to the upper section of the variable-diameter piston 4201, and the safety opening hole 2102 is located above the opening sleeve 510 so that the fluid in the center tube 210 can be pressed to the upper section of the opening sleeve 510. The wire plug 220 is used to prevent the fluid in the center tube 210 from directly flowing to the outside of the center tube 210, so that the fluid in the center tube 210 flows to the outside of the center tube 210 through the variable-section pressure-limiting structure 420 or the safety opening structure 50.

[0065] In some embodiments, an external pressure connecting hole 4102 and a pressure limiting connecting hole 4101 are provided on the variable diameter cylinder 410. The external pressure connecting hole 4102 is located above the fixed seat 4203 and outside the moving coverage range of the variable diameter piston 4201. The pressure limiting connecting hole 4101 is located below the pressure limiting flow control hole 2101 and within the moving coverage range of the variable diameter piston 4201.

[0066] It should be noted that a pressure-limiting connecting hole 4101 and an external-pressure connecting hole 4102 are provided on the variable-diameter cylinder 410. The pressure-limiting connecting hole 4101 is located below the pressure-limiting flow control hole 2101 in the height direction, and the external-pressure connecting hole 4102 is located above the fixed seat 4203 and below the lower end surface of the variable-diameter piston 4201. When the variable-diameter piston 4201 is in the original position, the variable-diameter piston 4201 does not block the pressure-limiting flow control hole 2101, but blocks the pressure-limiting connecting hole 4101. At this time, the channel between the central tube 210 and the wall tube assembly 30 is blocked and cannot be connected; when the variable-diameter piston 4201 is in the connecting position, the variable-diameter piston 4201 neither blocks the pressure-limiting flow control hole 2101 nor the pressure-limiting connecting hole 4101 At this time, the channel between the central tube 210 and the wall tube assembly 30 is not blocked, and communication is achieved; wherein, the external pressure connecting hole 4102 is used to lead the fluid in the well to the bottom of the variable-diameter piston 4201, and the lower end of the variable-diameter piston 4201 is subjected to the upward pressure of the fluid in the well, while the upper end of the variable-diameter piston 4201 is subjected to the downward pressure of the fluid pressed to the upper end of the variable-diameter piston 4201 by the pressure-limiting flow control hole 2101. When the pressure difference between the pressure at the upper end of the variable-diameter piston 4201 and the pressure at the lower end of the variable-diameter piston 4201 reaches a preset pressure difference, the fluid in the central tube 210 pushes the variable-diameter piston 4201 downward, so that the central tube 210 is connected to the wall tube assembly 30 through the pressure-limiting flow control hole 2101 and the pressure-limiting connecting hole 4101.

[0067] In some embodiments, the return member 4202 is a return spring.

[0068] It should be noted that the use of a spring as the reset member 4202 has the advantages of being easy to install and use and being low in price.

[0069] In some embodiments, the connection structure 10 includes: a variable buckle joint 110, the lower end of which has an inner connecting end and a middle connecting end; an upper joint 120, the lower end of which has an inner buckle and an outer connecting end, and the upper joint 120 is connected to the variable buckle joint 110 via the inner buckle.

[0070] It should be noted that the inner side of the lower end of the variable buckle joint 110 is the inner connecting end, the outer side of the lower end of the variable buckle joint 110 is the middle connecting end, the inner side of the lower end of the upper joint 120 is the inner buckle, and the outer side of the lower end of the upper joint 120 is the outer connecting end. The upper joint 120 is connected to the outer side of the upper end of the variable buckle joint 110 through the inner buckle. After such connection, the lower end of the connecting structure 10 has an inner connecting end, a middle connecting end and an outer connecting end arranged in sequence from the inside to the outside.

[0071] In some embodiments, the connection structure 10 includes a casing short-circuit and a casing coupling 140 ; ​​the lower end of the casing short-circuit is connected to the upper joint 120 , and the upper end of the casing short-circuit is connected to the casing coupling 140 .

[0072] It should be noted that the upper end of the sleeve coupling is used to connect to the float collar, and the connection interface of the float collar is usually different from the interface of the upper joint 120. Therefore, it is necessary to connect a sleeve coupling 140 through a sleeve short circuit, and then connect the float collar through the sleeve coupling 140.

[0073] In some embodiments, the wall tube assembly 30 includes: an outer wall tube 310 , the upper end of which is connected to the outer connection end; and a short sleeve 320 , which is connected to the lower end of the outer wall tube 310 .

[0074] It should be noted that the lower end of the wall tube assembly 30 usually needs to be connected to a float shoe, and the interface of the float shoe may be different from the interface of the outer wall tube, so the connection interface of the outer wall tube can be converted to the same interface as the float shoe through a short sleeve for connection.

[0075] In summary, compared with the prior art, the embodiment of the present invention can simulate the pressure of the fluid in the wellbore on the pressure limiting flow controller 1 for cementing by connecting the wellbore simulation component 2 to the output end of the pressure limiting flow controller 1 for cementing; by connecting the driving component 3 to the input end of the pressure limiting flow controller 1 for cementing, fluid can be injected into the pressure limiting flow controller 1 for cementing, which can solve the problem of the current lack of detection tooling and detection method for the piston opening pressure and safety pressure of the pressure limiting flow controller 1 for cementing, and can simulate the working state of the pressure limiting flow controller 1 for cementing on the ground, and detect the piston opening pressure and safety pressure of the pressure limiting flow controller 1 for cementing on the ground, to ensure that the settings of the piston opening pressure and safety pressure of the pressure limiting flow controller 1 for cementing meet the requirements.

[0076] Second, as Figure 3 As shown, this embodiment provides a method for detecting a pressure limiting flow controller for cementing, comprising:

[0077] S101: Setting the pressure limiting structure detection data of the pressure limiting flow controller 1 for cementing, wherein the pressure limiting structure detection data includes the normal piston opening pressure of the variable cross-section pressure limiting structure 420 of the pressure limiting flow controller 1 for cementing and the normal safety pressure of the safety opening structure 50 of the pressure limiting flow controller 1 for cementing;

[0078] It should be noted that the normal piston opening pressure is usually set according to the depth of the wellbore that the cementing pressure limiting flow controller 1 needs to penetrate and the density of the fluid in the wellbore. When conducting ground simulation testing, clean water is pumped into the output end of the cementing pressure limiting flow controller 1 through the wellbore simulation component 2 to simulate the pressure of the fluid in the wellbore on the output end of the cementing pressure limiting flow controller 1, and clean water is pumped into the input end of the cementing pressure limiting flow controller 1 through the drive component 3 to simulate the pressure of the fluid pumped into the pump truck on the input end of the cementing pressure limiting flow controller 1.

[0079] In some embodiments, the pressure limiting structure detection data of the pressure limiting flow controller 1 for cementing is set, wherein the pressure limiting structure detection data includes the normal piston opening pressure of the variable-section pressure limiting structure 420 of the pressure limiting flow controller 1 for cementing and the normal safety pressure of the safety opening structure 50 of the pressure limiting flow controller 1 for cementing, including: adjusting the cross-sectional area of ​​the upper end of the variable-diameter piston 4201 of the variable-section pressure limiting structure 420, and / or the cross-sectional area of ​​the lower end of the variable-diameter piston 4201 to set the normal piston opening pressure; adjusting the specifications of the shear pins 520 of the safety opening structure 50 to set the normal safety pressure; wherein the normal safety pressure is greater than the normal piston opening pressure.

[0080] It should be noted that the cross-sectional area of ​​the upper end of the variable piston 4201 is different from the cross-sectional area of ​​the lower end of the variable piston 4201. Usually, the cross-sectional area of ​​the upper end of the variable piston 4201 is smaller than the cross-sectional area of ​​the lower end of the variable piston 4201. When the same pressure of fluid is injected into the upper end of the variable piston 4201 and the lower end of the variable piston 4201, the pressure applied to the lower end of the variable piston 4201 is greater than the pressure applied to the upper end of the variable piston 4201. When performing the cementing process, the fluid medium at the input end of the cementing pressure limiting flow controller 1 and the output end of the cementing pressure limiting flow controller 1 are usually different. Usually, the fluid density at the input end of the cementing pressure limiting flow controller 1 is greater than the fluid density at the output end of the cementing pressure limiting flow controller 1. When performing ground detection, the difference caused by different fluid densities can be simulated by increasing the pressure of the driving pressure pump 301, even if the output pressure of the driving pressure pump 301 is greater than the output pressure of the wellbore pressure pump 201.

[0081] It should be noted that when adjusting the opening pressure of the normal piston, if the opening pressure of the normal piston is to be increased, the cross-sectional area of ​​the upper end of the variable piston 4201 can be reduced, and / or the cross-sectional area of ​​the lower end of the variable piston 4201 can be increased; if the opening pressure of the normal piston is to be reduced, the cross-sectional area of ​​the upper end of the variable piston 4201 can be increased, and / or the cross-sectional area of ​​the lower end of the variable piston 4201 can be reduced.

[0082] It should be noted that the normal piston opening pressure of the variable-section pressure limiting structure 420 of the cementing pressure limiting flow controller 1 and the normal safety pressure of the safety opening structure 50 of the cementing pressure limiting flow controller 1 can be detected together or separately. The normal safety pressure is used to open the cementing pressure limiting flow controller 1 when the normal piston of the variable-section pressure limiting structure 420 cannot be opened normally due to a malfunction, so that the cementing process can proceed normally. When detecting the normal piston opening pressure, the normal safety pressure can be the normal piston opening pressure + the shearing pressure of the shear nails 520 of the safety opening structure 50 - 5Mpa.

[0083] S102: connecting the output end of the cementing pressure limiting flow controller 1 to the wellbore simulation component 2;

[0084] S103: connecting the input end of the cementing pressure limiting flow controller 1 to the driving assembly 3;

[0085] In some embodiments, the output end of the pressure limiting flow controller 1 for cementing is connected to the wellbore simulation component 2, specifically: the output end of the pressure limiting flow controller 1 for cementing is connected to the wellbore pressure pump 201 through the wellbore connection structure 202; the input end of the pressure limiting flow controller 1 for cementing is connected to the drive component 3, specifically: the input end of the pressure limiting flow controller 1 for cementing is connected to the drive pressure pump 301 through the drive connection structure 302.

[0086] It should be noted that the wellbore connection structure 202 may include a wellbore connection cap 2022 and a wellbore pressure joint 2021, one end of the wellbore connection cap 2022 is connected to the pipeline, and the other end of the wellbore connection cap 2022 is connected to the wellbore pressure joint 2021, and the wellbore pressure joint 2021 is connected to the output end of the pressure limiting flow controller 1 for cementing, wherein the specific structure and form of the wellbore pressure joint 2021 can be adjusted according to the structure of the output end of the pressure limiting flow controller 1 for cementing.

[0087] It should be noted that the driving connection structure 302 may include a driving connection cap 3022 and a driving pressure joint 3021, one end of the driving connection cap 3022 is connected to the pipeline, and the other end of the driving connection cap 3022 is connected to the driving pressure joint 3021, and the driving pressure joint 3021 is connected to the input end of the pressure limiting flow controller 1 for cementing, wherein the specific structure and form of the driving pressure joint 3021 can be adjusted according to the structure of the input end of the pressure limiting flow controller 1 for cementing.

[0088] S104: The normal piston opening pressure of the variable-section pressure limiting structure 420 of the pressure limiting flow controller 1 for cementing is detected by the wellbore simulation component 2 and the driving component 3.

[0089] In some embodiments, the opening pressure of the variable-section pressure limiting structure 420 of the pressure limiting flow controller 1 for cementing is detected by the wellbore simulation component 2 and the drive component 3, specifically: the wellbore pressure pump 201 of the wellbore simulation component 2 is turned on, and the pressure at the output end of the pressure limiting flow controller 1 for cementing is increased to the simulated well depth pressure; the drive pressure pump 301 of the drive component 3 is turned on, and the pressure at the input end of the pressure limiting flow controller 1 for cementing is increased to the normal piston opening pressure; if the variable diameter piston 4201 of the variable-section pressure limiting structure 420 moves to the piston opening position, and the opening sleeve 510 of the safety opening structure 50 is not moved to the safety opening position, then the normal piston opening pressure setting is qualified.

[0090] It should be noted that when testing the normal piston opening pressure, the wellbore pressure pump 201 of the wellbore simulation component 2 is usually opened first. When the wellbore pressure pump 201 pumps clean water into the output end of the cementing pressure limiting flow controller 1, the output pressure is gradually increased to reach the simulated well depth pressure. Then the driving pressure pump 301 of the driving component 3 is opened. When the driving pressure pump 301 pumps clean water into the input end of the cementing pressure limiting flow controller 1, the output pressure is gradually increased to reach the normal piston opening pressure. At this time, if the variable diameter piston 4201 of the variable cross-section pressure limiting structure 420 is not moved to the piston opening position, and / or the opening sleeve 510 of the safety opening structure 50 is moved to the safety opening position, the normal piston opening pressure setting is unqualified, and the variable diameter piston 4201 of the variable cross-section pressure limiting structure 420 needs to be checked.

[0091] It should be noted that if Figure 1 As shown, the normal position of the variable diameter piston 4201 of the variable cross-section pressure limiting structure 420 is to cover the pressure limiting connecting hole, and the piston opening position is located below the normal position of the variable diameter piston 4201. When the variable diameter piston 4201 is located at the piston opening position, the variable diameter piston 4201 moves downward to expose the pressure limiting connecting hole 4101, so that the center tube 210 is connected to the wall tube assembly 30; the normal position of the opening sleeve 510 of the safety opening structure 50 is to be embedded and sealed with the installation groove 42031, and the safety opening position of the opening sleeve 510 of the safety opening structure 50 is below the normal position of the opening sleeve 510. When the opening sleeve 510 is in the safety opening position, the shear pins 520 of the opening sleeve 510 are cut off, so that the center tube 210 is connected to the wall tube assembly 30.

[0092] It should be noted that, usually, sensors are used to detect whether the variable-diameter piston 4201 has moved to the piston opening position and whether the opening sleeve 510 of the safety opening structure 50 has moved to the safety opening position.

[0093] In some embodiments, the detection method of the pressure limiting flow controller 1 for cementing further includes: setting safety structure detection data of the pressure limiting flow controller 1 for cementing, wherein the safety structure detection data includes the abnormal piston opening pressure of the variable cross-section pressure limiting structure 420 of the pressure limiting flow controller 1 for cementing and the abnormal safety pressure of the safety opening structure 50 of the pressure limiting flow controller 1 for cementing; and detecting the abnormal safety pressure of the safety opening structure 50 of the pressure limiting flow controller 1 for cementing through the wellbore simulation component 2 and the drive component 3.

[0094] It should be noted that in some cases, the safety pressure of the safety opening structure 50 needs to be tested separately to ensure that it can meet the use requirements. This is equivalent to testing the working performance of the pressure limiting flow controller 1 for cementing under abnormal working conditions.

[0095] In some embodiments, the safety structure detection data of the pressure limiting flow controller 1 for cementing is set, wherein the safety structure detection data includes the abnormal piston opening pressure of the variable-section pressure limiting structure 420 of the pressure limiting flow controller 1 for cementing and the abnormal safety pressure of the safety opening structure 50 of the pressure limiting flow controller 1 for cementing, specifically: adjusting the cross-sectional area of ​​the upper end of the variable-diameter piston 4201 of the variable-section pressure limiting structure 420, and / or the cross-sectional area of ​​the lower end of the variable-diameter piston 4201 to set the abnormal piston opening pressure; adjusting the specifications of the shear pins 520 of the safety opening structure 50 to set the abnormal safety pressure; wherein the abnormal safety pressure is less than the abnormal piston opening pressure.

[0096] In some embodiments, the abnormal safety pressure of the safety opening structure 50 of the pressure limiting flow controller 1 for cementing is detected by the wellbore simulation component 2 and the driving component 3, specifically: the wellbore pressure pump 201 of the wellbore simulation component 2 is turned on, and the pressure at the output end of the pressure limiting flow controller 1 for cementing is increased to the simulated well depth pressure; the driving pressure pump 301 of the driving component 3 is turned on, and the pressure at the input end of the pressure limiting flow controller 1 for cementing is increased to the abnormal piston opening pressure; if the opening sleeve 510 of the safety opening structure 50 is moved to the safe opening position, and the variable diameter piston 4201 of the variable cross-section pressure limiting structure 420 is not moved to the piston opening position, then the abnormal safety pressure setting is qualified.

[0097] It should be noted that when detecting the abnormal safety pressure, the wellbore pressure pump 201 of the wellbore simulation component 2 is usually opened first. When the wellbore pressure pump 201 pumps clean water into the output end of the cementing pressure limiting flow controller 1, the output pressure is gradually increased to reach the simulated well depth pressure. Then the driving pressure pump 301 of the driving component 3 is opened. When the driving pressure pump 301 pumps clean water into the input end of the cementing pressure limiting flow controller 1, the output pressure is gradually increased to reach the abnormal safety pressure. At this time, if the variable diameter piston 4201 of the variable-section pressure limiting structure 420 moves to the piston opening position, and / or the opening sleeve 510 of the safety opening structure 50 is not moved to the safe opening position, the abnormal safety pressure setting is unqualified, and the shear nail 520 of the safety opening structure 50 needs to be checked.

[0098] In summary, the embodiment of the present invention sets the pressure limiting structure detection data of the pressure limiting flow controller 1 for cementing, wherein the pressure limiting structure detection data includes the normal piston opening pressure of the variable cross-section pressure limiting structure 420 of the pressure limiting flow controller 1 for cementing and the normal safety pressure of the safety opening structure 50 of the pressure limiting flow controller 1 for cementing; the output end of the pressure limiting flow controller 1 for cementing is connected to the wellbore simulation component 2; the input end of the pressure limiting flow controller 1 for cementing is connected to the drive component 3; the normal piston opening pressure of the variable cross-section pressure limiting structure 420 of the pressure limiting flow controller 1 for cementing is detected through the wellbore simulation component 2 and the drive component 3, so that the working state of the pressure limiting flow controller 1 for cementing can be simulated on the ground, and the piston opening pressure and safety pressure of the pressure limiting flow controller 1 for cementing can be detected on the ground, so as to ensure that the settings of the piston opening pressure and safety pressure of the pressure limiting flow controller 1 for cementing meet the requirements.

[0099] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In the description of the present invention, the first feature "above" or "below" the second feature may include the first and second features being in direct contact, or the first and second features not being in direct contact but being in contact through another feature between them.

[0100] In the description of the present invention, “on”, “over” and “above” a first feature from a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0101] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0102] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0103] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A pressure limiting flow controller detection tool for cementing, characterized in that: include: A wellbore simulation component, connected to the output end of the cementing pressure limiting flow controller, and used to simulate the pressure of the wellbore fluid on the cementing pressure limiting flow controller; A driving assembly is connected to the input end of the pressure limiting flow controller for cementing and is used to inject fluid into the pressure limiting flow controller for cementing.

2. The pressure limiting flow controller detection tool for cementing according to claim 1 is characterized in that: The wellbore simulation component comprises: Wellbore pressure pump; A wellbore connection structure, one end of which is connected to the wellbore pressure pump, and the other end of which is connected to the output end of the cementing pressure limiting flow controller; The wellbore pressure gauge is arranged on the wellbore connection structure or the wellbore pressure pump.

3. The pressure limiting flow controller detection tool for cementing according to claim 1 is characterized in that: The drive assembly comprises: Drive the pressure pump; A driving connection structure, one end of which is connected to the driving pressure pump, and the other end of which is connected to the input end of the cementing pressure limiting flow controller; The driving pressure gauge is arranged on the driving connection structure or the driving pressure pump.

4. A method for detecting a pressure limiting flow controller for cementing, applied to a tool for detecting a pressure limiting flow controller for cementing as claimed in any one of claims 1 to 3, characterized in that: include: Setting the pressure limiting structure detection data of the pressure limiting flow controller for cementing, wherein the pressure limiting structure detection data includes the normal piston opening pressure of the variable cross-section pressure limiting structure of the pressure limiting flow controller for cementing and the normal safety pressure of the safety opening structure of the pressure limiting flow controller for cementing; Connecting the output end of the cementing pressure limiting flow controller to the wellbore simulation component; Connecting the input end of the cementing pressure limiting flow controller to the driving assembly; The normal piston opening pressure of the variable-section pressure-limiting structure of the pressure-limiting flow controller for cementing is detected by the wellbore simulation component and the drive component.

5. The method for detecting a pressure limiting flow controller for cementing according to claim 4, characterized in that: The pressure limiting structure detection data of the pressure limiting flow controller for cementing is set, wherein the pressure limiting structure detection data includes the normal piston opening pressure of the variable cross-section pressure limiting structure of the pressure limiting flow controller for cementing and the normal safety pressure of the safety opening structure of the pressure limiting flow controller for cementing, including: The normal piston opening pressure is set by adjusting the cross-sectional area of ​​the upper end of the variable-diameter piston of the variable-section pressure-limiting structure and / or the cross-sectional area of ​​the lower end of the variable-diameter piston; Adjusting the specifications of the shear pins of the safety opening structure to set the normal safety pressure; Wherein, the normal safety pressure is greater than the normal piston opening pressure.

6. The method for detecting a pressure limiting flow controller for cementing according to claim 4, characterized in that: The output end of the cementing pressure limiting flow controller is connected to the wellbore simulation component, specifically: Connecting the output end of the cementing pressure limiting flow controller to the wellbore pressure pump through the wellbore connection structure; The step of connecting the input end of the cementing pressure limiting flow controller to the driving assembly is specifically as follows: The input end of the cementing pressure limiting flow controller is connected to a driving pressure pump through a driving connection structure.

7. The method for detecting a pressure limiting flow controller for cementing according to claim 4, characterized in that: The normal piston opening pressure of the variable cross-section pressure limiting structure of the pressure limiting flow controller for cementing is detected by the wellbore simulation component and the drive component, specifically: Turning on the wellbore pressure pump of the wellbore simulation component and raising the pressure at the output end of the cementing pressure limiting flow controller to the simulated well depth pressure; Turn on the driving pressure pump of the driving assembly, and raise the pressure at the input end of the cementing pressure limiting flow controller to the normal piston opening pressure; If the variable diameter piston of the variable cross-section pressure limiting structure moves to the piston opening position, and the opening sleeve of the safety opening structure does not move to the safety opening position, then the normal piston opening pressure setting is qualified.

8. The method for detecting a pressure limiting flow controller for cementing according to claim 4, characterized in that: Also includes: Setting safety structure detection data of the pressure limiting flow controller for cementing, wherein the safety structure detection data includes the abnormal piston opening pressure of the variable cross-section pressure limiting structure of the pressure limiting flow controller for cementing and the abnormal safety pressure of the safety opening structure of the pressure limiting flow controller for cementing; The abnormal safety pressure of the safety opening structure of the pressure limiting flow controller for cementing is detected by the wellbore simulation component and the driving component.

9. The method for detecting a pressure limiting flow controller for cementing according to claim 8, characterized in that: The safety structure detection data of the pressure limiting flow controller for cementing is set, wherein the safety structure detection data includes the abnormal piston opening pressure of the variable cross-section pressure limiting structure of the pressure limiting flow controller for cementing and the abnormal safety pressure of the safety opening structure of the pressure limiting flow controller for cementing, specifically: The opening pressure of the abnormal piston is set by adjusting the cross-sectional area of ​​the upper end of the variable-diameter piston of the variable-section pressure-limiting structure and / or the cross-sectional area of ​​the lower end of the variable-diameter piston; The abnormal safety pressure is set by adjusting the specifications of the shear pins of the safety opening structure; Wherein, the abnormal safety pressure is less than the abnormal piston opening pressure.

10. The method for detecting a pressure limiting flow controller for cementing according to claim 8, characterized in that: The detecting of the abnormal safety pressure of the safety opening structure of the pressure limiting flow controller for cementing by the wellbore simulation component and the driving component is specifically as follows: Turning on the wellbore pressure pump of the wellbore simulation component and raising the pressure at the output end of the cementing pressure limiting flow controller to the simulated well depth pressure; Turn on the driving pressure pump of the driving assembly, and raise the pressure at the input end of the cementing pressure limiting flow controller to the opening pressure of the abnormal piston; If the opening sleeve of the safety opening structure moves to the safety opening position and the variable diameter piston of the variable cross-section pressure limiting structure does not move to the piston opening position, the abnormal safety pressure setting is qualified.

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