A casing gas-tight threaded joint for an oil well casing head

Abstract

The invention belongs to the technical field of oil drilling equipment, and particularly relates to a casing air-tight threaded joint for an oil well wellhead casing head, comprising a connecting pipe, wherein the upper and lower ends of the connecting pipe are respectively butted with an upper threaded joint and a lower threaded joint, two threaded casings are slidably connected to the connecting pipe, the upper threaded joint and the lower threaded joint are respectively threadedly connected with the two threaded casings, and air bags are arranged between the two threaded casings and the connecting pipe. Initially, the air bags are in a deflated state, and after the upper threaded joint and the lower threaded joint are butted and fixed at the upper and lower ends of the connecting pipe, nitrogen is filled into the air bags in the upper and lower threaded casings, the air bags expand, the upper end of the air bags are closely attached to the inner wall of the threaded casing, the lower end of the air bags are closely attached to the outer wall of the connecting pipe, one end of the air bags are closely attached to the threaded connection between the connecting pipe and the threaded casing, and the other end of the air bags are closely attached to the threaded connection between the upper threaded joint and the threaded casing, thereby preventing oil and gas from leaking from the connection between the upper threaded joint and the threaded casing.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum drilling equipment, and in particular relates to a casing gas-tight threaded joint for an oil wellhead casing head. Background Art

[0002] At present, the main threaded joint form is API standard thread, which has a simple structure and strong versatility, but weak load-bearing capacity. Threaded joints need to face a variety of load conditions during underground service, including tension, compression, bending, torsion, etc. Existing threaded joints are prone to damage or gaps with oil well pipes after long-term use, causing oil and gas leakage;

[0003] For example, patent application number CN202410183815.1 is an ultra-high pressure casing head for preventing leakage at an oilfield wellhead, comprising a casing joint, a slide groove is provided in an annular manner on the casing joint, a core shaft type hanger is threadedly connected to the casing joint, an upper sealing ring and a lower sealing ring are slidably provided in the slide groove, a metal sealing ring is provided on the side of the upper sealing ring away from the lower sealing ring; the external sliding seal of the core shaft type hanger is connected to a slider, the slider is fixedly connected to a push seat, the inclined surface of the push seat abuts against the inclined surface of the metal sealing ring; a positioning mechanism is provided between the slider and the casing joint, but the disadvantage of this technical solution is that the casing joint has a weak bearing capacity, and is easily damaged after long-term use or has a gap with the oil well pipe, causing leakage of oil and gas. Summary of the invention

[0004] The object of the present invention is to provide a casing gas-tight threaded joint for an oil well wellhead casing head to solve the problems in the prior art. The specific technical scheme is as follows:

[0005] A casing airtight threaded joint for an oil well wellhead casing head comprises a connecting pipe, wherein the upper and lower ends of the connecting pipe are respectively connected to an upper threaded joint and a lower threaded joint, two threaded casings are slidably connected to the connecting pipe, the upper threaded joint and the lower threaded joint are respectively threadedly connected to the two threaded casings, and air bags are arranged between the two threaded casings and the connecting pipe.

[0006] Furthermore, a sealing ring 1 is provided at the connection between the connecting pipe and the threaded sleeve, and a sealing ring 2 is provided at the connection between the upper threaded joint and the lower threaded joint and the connecting pipe.

[0007] Furthermore, a pressurizing component is provided on one side of the airbag, and the pressurizing component includes a support tube 1. The airbag is fixedly connected to the support tube 1, and the airbag is communicated with the support tube 1. An air intake pipe is slidably connected inside the support tube 1, and four air intake holes are provided on the air intake pipe. A spring is provided between the support tube 1 and the air intake pipe, and the end of the support tube 1 is threadedly connected to a cap 1.

[0008] Furthermore, a pressure measuring component is provided on the other side of the airbag, and the pressure measuring component includes a support tube 2. The airbag is fixedly connected to the support tube 2, the airbag is communicated with the support tube 2, a piston 1 is slidably connected inside the support tube 2, the piston 1 is fixedly connected to the piston rod, the piston rod is slidably connected to the support tube 2, and a spring 2 is provided between the support tube 2 and the piston 1.

[0009] Furthermore, the piston rod is provided with scale lines, and the two ends of the support cylinder are threadedly connected to the second cap, and the second cap is in a transparent state.

[0010] Furthermore, a supporting component is fixed in the middle of the connecting tube, and the supporting component includes a fixing ring, which is fixed in the middle of the connecting tube, and the fixing ring is slidably connected to the inner ring frame, and a plurality of springs are arranged between the fixing ring and the inner ring frame.

[0011] Furthermore, the inner ring frame is rotatably connected to multiple upper leg frames, the upper leg frames are rotatably connected to a turntable, an outer tube and a screw rod are fixed on the turntable, the outer tube is slidably connected to the lower leg frame, the screw rod is threadedly connected to the lower leg frame, and the lower end of the lower leg frame is rotatably connected to a support plate.

[0012] Furthermore, the connecting tube is provided with a quantitative sampling component, which includes a liquid outlet pipe, which is fixed on the side wall of the connecting tube and is connected to the inside of the connecting tube. The liquid outlet pipe is slidably connected to the liquid collecting pipe. A fixing ring is provided on the liquid outlet pipe, which is rotatably connected to the second screw rod, which is threadedly connected to the liquid collecting pipe. A scale is fixed to the end of the liquid collecting pipe, which is slidably connected to the fixing ring. A discharge pipe 1 is fixed to the lower end of the liquid collecting pipe, a valve 1 is provided in the liquid outlet pipe, and a valve 2 is provided in the discharge pipe 1.

[0013] Furthermore, the connecting pipe is provided with a pressure relief and explosion-proof component, which includes a pressure relief pipe, which is fixed on the side wall of the connecting pipe and is connected to the inside of the connecting pipe, a discharge pipe 2 is fixed to the lower end of the pressure relief pipe, a bracket is fixed to the end of the pressure relief pipe, a piston 2 is slidably connected to the inside of the pressure relief pipe, the piston 2 is fixedly connected to the push rod, the piston 2 is fixedly connected to one end of a spring 4, the other end of the spring 4 is fixed to a fixed disk, the fixed disk is rotatably connected to a spring push plate, the spring push plate is threadedly connected to the pressure relief pipe, a long tube is fixed at the center position of the spring push plate, the fixed disk is rotatably connected to the long tube, the push rod is slidably connected to the long tube, and the end of the long tube is fixedly connected to a rotating wheel.

[0014] Furthermore, the push rod is fixedly connected to the long rod, the long rod is fixedly connected to the bent rod, a pointer is provided at the end of the bent rod, a calibration line is provided on the rotating wheel, a first scale line and a second scale line are provided on the bracket, the pointer points to the scale position on the first scale line, the calibration line corresponds to the scale position on the second scale line, the bracket is fixedly connected to the alarm switch, the alarm switch is electrically connected to the alarm through a transmission line, and the alarm is fixed at the lower end of the bracket.

[0015] The advantages of the present invention are:

[0016] The upper and lower ends of the connecting pipe are respectively butted with the upper threaded joint and the lower threaded joint, and the threaded joint is fixed to the upper end of the connecting pipe by rotating the threaded sleeve and the threaded joint, and the lower threaded joint is fixed to the lower end of the connecting pipe by rotating the threaded sleeve and the lower threaded joint. Air bags are arranged between the two threaded sleeves and the connecting pipe. Initially, the air bags are in a deflated state. After the upper threaded joint and the lower threaded joint are butted and fixed at the upper and lower ends of the connecting pipe, nitrogen is filled into the air bags in the upper and lower threaded sleeves to expand the air bags. The upper end of the air bags is tightly against the inner wall of the threaded sleeve, the lower end of the air bags is tightly against the outer wall of the connecting pipe, one end of the air bags is tightly against the threaded connection between the connecting pipe and the threaded sleeve, and the other end of the air bag in the upper threaded sleeve is One end is tightly attached to the threaded connection between the upper threaded joint and the threaded casing, and the other end of the airbag in the threaded casing below is tightly attached to the threaded connection between the lower threaded joint and the threaded casing, thereby preventing oil and gas from leaking from the connection between the upper threaded joint and the threaded casing or the connection between the lower threaded joint and the threaded casing. The upper threaded joint and the threaded casing need to face various load conditions during downhole service, including tension, compression, bending, torsion, etc. Gaps are prone to appear at the threaded connection between the upper threaded joint and the threaded casing, and oil and gas are prone to leak out in the gaps. Since the shape of the airbag is variable, the airbag can still be tightly attached to the connection between the upper threaded joint and the threaded casing when the upper threaded joint and the threaded casing are slightly deformed, thereby preventing oil and gas leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 It is a schematic diagram of the connecting pipe structure of the present invention;

[0019] Figure 3 It is a schematic diagram of the threaded casing structure of the present invention;

[0020] Figure 4 for Figure 3 A partial enlarged view of the middle part;

[0021] Figure 5 for Figure 3 A partial enlarged view of point B in the middle;

[0022] Figure 6 The supporting component structure of the present invention is schematically shown in FIG. Figure 1 ;

[0023] Figure 7 The supporting component structure of the present invention is schematically shown in FIG. Figure 2 ;

[0024] Figure 8 for Figure 7 A partial enlarged view of point C in the middle;

[0025] Fig. 9The supporting component structure of the present invention is schematically shown in FIG. Figure 3 ;

[0026] Fig.10 The structure of the quantitative sampling component of the present invention is shown in FIG. Figure 1 ;

[0027] Fig.11 The structure of the quantitative sampling component of the present invention is shown in FIG. Figure 2 ;

[0028] Fig.12 The structure of the pressure relief explosion-proof component of the present invention is shown in FIG. Figure 1 ;

[0029] Fig.13 for Fig.12 A partial enlarged view of point D in the middle;

[0030] Fig.14 The structure of the pressure relief explosion-proof component of the present invention is shown in FIG. Figure 2 ;

[0031] Fig.15 for Fig.14 A partial enlarged view of point E in the middle;

[0032] Fig.16 The structure of the pressure relief explosion-proof component of the present invention is shown in FIG. Figure 3 ;

[0033] Description of the markings in the figure:

[0034] Connecting pipe 1; threaded sleeve 2; air bag 3; pressurizing component 4; support cylinder 1 401; air inlet pipe 402; air inlet hole 403; spring 1 404; cap 1 405; pressure measuring component 5; support cylinder 2 501; piston 1 502; piston rod 503; spring 2 504; cap 2 505; support component 6; fixing ring 601; spring 3 602; inner ring frame 603; upper leg frame 604; turntable 605; outer tube 606; screw 1 607; lower leg frame 608; support plate 609; quantitative sampling component 7; liquid outlet pipe 701; liquid collecting pipe 702; fixing ring 703; scale Ruler 704; valve one 705; valve two 706; screw two 707; discharge pipe one 708; pressure relief explosion-proof component 8; pressure relief pipe 801; discharge pipe two 802; bracket 803; piston two 804; push rod 805; spring four 806; fixed plate 807; spring push plate 808; long tube 809; rotating wheel 810; long rod 811; bent rod 812; first scale line 813; second scale line 814; calibration line 815; alarm switch 816; transmission line 817; alarm 818; sealing ring one 9; sealing ring two 10; upper threaded joint 11; lower threaded joint 12. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship 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 limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0037] Embodiment 1

[0038] like Figure 1-16 As shown, a casing airtight threaded joint for an oil well wellhead casing head comprises a connecting pipe 1, the upper and lower ends of the connecting pipe 1 are respectively connected to an upper threaded joint 11 and a lower threaded joint 12, two threaded casings 2 are slidably connected to the connecting pipe 1, the upper threaded joint 11 and the lower threaded joint 12 are respectively threadedly connected to the two threaded casings 2, and air bags 3 are arranged between the two threaded casings 2 and the connecting pipe 1;

[0039] The working principle of the above technical solution is as follows: the upper and lower ends of the connecting pipe 1 are respectively connected with the upper threaded joint 11 and the lower threaded joint 12, and the threaded joint 11 is fixed to the upper end of the connecting pipe 1 by threaded rotation of the threaded sleeve 2 and the threaded joint 11, and the lower threaded joint 12 is fixed to the lower end of the connecting pipe 1 by threaded rotation of the threaded sleeve 2 and the lower threaded joint 12, and an airbag 3 is arranged between the two threaded sleeves 2 and the connecting pipe 1. Initially, the airbag 3 is in a deflated state. After the upper threaded joint 11 and the lower threaded joint 12 are connected and fixed to the upper and lower ends of the connecting pipe 1, nitrogen is filled into the airbag 3 in the upper and lower threaded sleeves 2, and the airbag 3 expands. The upper end of the airbag 3 is tightly attached to the inner wall of the threaded sleeve 2, and the lower end of the airbag 3 is tightly attached to the outer wall of the connecting pipe 1. One end of the airbag 3 is tightly attached to the threaded connection between the connecting pipe 1 and the threaded sleeve 2, and the airbag in the upper threaded sleeve 2 The other end of 3 is in close contact with the threaded connection between the upper threaded joint 11 and the threaded casing 2, and the other end of the airbag 3 in the lower threaded casing 2 is in close contact with the threaded connection between the lower threaded joint 12 and the threaded casing 2, thereby preventing oil and gas from leaking from the connection between the upper threaded joint 11 and the threaded casing 2 or the connection between the lower threaded joint 12 and the threaded casing 2. The upper threaded joint 11 and the threaded casing 2 need to face a variety of load conditions during downhole service, including tension, compression, bending, torsion, etc., and gaps are prone to occur at the threaded connection between the upper threaded joint 11 and the threaded casing 2, and oil and gas are prone to leak out in the gaps. Since the airbag 3 is changeable in shape, the airbag 3 can still be in close contact with the connection between the upper threaded joint 11 and the threaded casing 2 when the upper threaded joint 11 and the threaded casing 2 are slightly deformed, preventing oil and gas leakage. The material of the airbag 3 can be rubber or silicone.

[0040] Embodiment 2

[0041] like Figure 1-16 As shown, a sealing ring 1 9 is provided at the connection between the connecting pipe 1 and the threaded sleeve 2, and a sealing ring 2 10 is provided at the connection between the upper threaded joint 11 and the lower threaded joint 12 and the connecting pipe 1;

[0042] The working principle of the above technical solution is: a sealing ring 9 increases the sealing performance of the connection between the connecting pipe 1 and the threaded sleeve 2 to prevent oil and gas from leaking from the connection between the connecting pipe 1 and the threaded sleeve 2; a sealing ring 10 increases the sealing performance of the connection between the upper threaded joint 11 and the connecting pipe 1; another sealing ring 10 increases the sealing performance of the connection between the lower threaded joint 12 and the connecting pipe 1 to further prevent oil and gas leakage.

[0043] Embodiment 3

[0044] like Figure 1-16As shown, a pressurizing component 4 is provided on one side of the airbag 3, and the pressurizing component 4 includes a support tube 401, the airbag 3 is fixedly connected to the support tube 401, the airbag 3 is communicated with the support tube 401, an air inlet pipe 402 is slidably connected in the support tube 401, and the air inlet pipe 402 is provided with four air inlet holes 403, a spring 404 is provided between the support tube 401 and the air inlet pipe 402, and the end of the support tube 401 is threadedly connected to the cap 405;

[0045] The working principle of the above technical solution is: the upper threaded joint 11 is docked at the upper end of the connecting pipe 1, the threaded sleeve 2 is threadedly fixed to the upper threaded joint 11, the cap 405 is rotated to separate the cap 405 from the support tube 401, the air pump or the air-inflating device or the air-inflating nozzle of the nitrogen injection device is inserted into the support tube 401, and the air intake pipe 402 is squeezed to move inside the support tube 401, driving the spring 404 to be compressed, and nitrogen is injected into the air intake pipe 402. The nitrogen enters the airbag 3 from the four air intake holes 403 on the air intake pipe 402, and the airbag 3 is expanded by the injected nitrogen, and the upper end of the airbag 3 is close to the threaded joint 11. On the inner wall of the threaded sleeve 2, the lower end of the airbag 3 is close to the outer wall of the connecting pipe 1, one end of the airbag 3 is close to the threaded connection between the connecting pipe 1 and the threaded sleeve 2, and the other end of the airbag 3 is close to the threaded connection between the upper threaded joint 11 and the threaded sleeve 2. After the nitrogen is injected, the nitrogen in the airbag 3 is squeezed and the elastic force of the spring 404 drives the intake pipe 402 to move upward, and the four intake holes 403 on the air pipe 402 are blocked by the inner wall of the support tube 401 to prevent the nitrogen in the airbag 3 from overflowing, and the cap 405 is re-threadedly connected to the support tube 401 to prevent someone from accidentally touching the intake pipe 402. At this time, the filling of nitrogen in the airbag 3 is completed.

[0046] Embodiment 4

[0047] like Figure 1-16 As shown, a pressure measuring component 5 is provided on the other side of the airbag 3, and the pressure measuring component 5 includes a second support cylinder 501, the airbag 3 is fixedly connected to the second support cylinder 501, the airbag 3 is communicated with the second support cylinder 501, a piston 1 502 is slidably connected in the second support cylinder 501, the piston 1 502 is fixedly connected to the piston rod 503, the piston rod 503 is slidably connected to the second support cylinder 501, and a spring 2 504 is provided between the second support cylinder 501 and the piston 1 502;

[0048] The piston rod 503 is provided with scale lines, and the end of the second support cylinder 501 is threadedly connected with the second cap 505, and the second cap 505 is in a transparent state;

[0049] The working principle of the above technical solution is: the nitrogen in the airbag 3 squeezes the piston 1 502 forward, driving the piston rod 503 to move forward. The piston rod 503 is provided with scale lines. The scale of the piston rod 503 exposed outside the support tube 2 501 can be seen through the cap 2 505, and then the air pressure in the airbag 3 at this time can be judged. When the air pressure in the airbag 3 increases, the nitrogen squeezes the piston 1 502 and the piston rod 503 to continue to move forward, and the scale lines set on the piston rod 503 are exposed more. When the air pressure in the airbag 3 decreases, the force of the nitrogen squeezing the piston 1 502 and the piston rod 503 decreases, the piston 1 502 and the piston rod 503 move backward, and the scale lines set on the piston rod 503 are exposed less. Therefore, the air pressure in the airbag 3 at this time can be judged by the scale lines on the piston rod 503 exposed to the scale outside the support tube 2 501. When it is detected that the air pressure in the airbag 3 is less than the preset value, nitrogen needs to be added to the airbag 3.

[0050] Embodiment 5

[0051] like Figure 1-16 As shown, a support component 6 is fixed in the middle of the connecting pipe 1, and the support component 6 includes a fixing ring 601, which is fixed in the middle of the connecting pipe 1, and the fixing ring 601 is slidably connected with an inner ring frame 603, and a plurality of springs 602 are arranged between the fixing ring 601 and the inner ring frame 603;

[0052] The inner ring frame 603 is rotatably connected to the plurality of upper leg frames 604, the upper leg frames 604 are rotatably connected to the turntable 605, an outer tube 606 and a screw rod 607 are fixed to the turntable 605, the outer tube 606 is slidably connected to the lower leg frame 608, the screw rod 607 is threadedly connected to the lower leg frame 608, and the lower end of the lower leg frame 608 is rotatably connected to a support plate 609;

[0053] The working principle of the above technical solution is: unfold multiple upper leg frames 604, rotate the turntable 605, drive the outer tube 606 and the screw 1 607 to rotate, drive the outer tube 606 and the lower leg frame 608 to slide and connect, drive the upper leg frame 604, the outer tube 606 and the lower leg frame 608 to extend and shorten as a whole, so that the support plate 609 is located at the edge of the oil well mouth, and fix the support plate 609 at the edge of the oil well mouth by pins. When the connecting pipe 1 vibrates, the fixed ring 601 and the inner ring frame 603 can slide, and the spring 3 602 adapts to the expansion and contraction, which has a shock-absorbing effect.

[0054] The beneficial effects of the above technical solution are as follows: by rotating the turntable 605, the overall length of the upper leg frame 604, the outer tube 606 and the lower leg frame 608 can be adjusted to adapt to the fixation of wellheads of different diameters; through multiple springs three 602, a shock-absorbing effect is provided to reduce the risk of the connecting pipe 1 and the threaded casing 2 being damaged by impact.

[0055] Embodiment 6

[0056] like Figure 1-16 As shown, the connecting pipe 1 is provided with a quantitative sampling component 7, which includes a liquid outlet pipe 701, which is fixed on the side wall of the connecting pipe 1 and communicated with the inside of the connecting pipe 1, and the liquid outlet pipe 701 is slidably connected with a liquid collecting pipe 702, and a fixing ring 703 is provided on the liquid outlet pipe 701, which is rotatably connected with a second screw rod 707, and the second screw rod 707 is threadedly connected with the liquid collecting pipe 702, and a scale 704 is fixed at the end of the liquid collecting pipe 702, and the scale 704 is slidably connected with the fixing ring 703, and a liquid discharge pipe 1 708 is fixed at the lower end of the liquid collecting pipe 702, and a valve 1 705 is provided in the liquid outlet pipe 701, and a valve 2 706 is provided in the liquid discharge pipe 1 708;

[0057] The working principle of the above technical solution is: rotate the second screw 707 to make the liquid outlet pipe 701 and the liquid collecting pipe 702 slide, drive the fixed ring 703 and the scale 704 to slide, the scale position on the edge of the fixed ring 703 corresponding to the scale 704 is the volume of the measured oil, after the volume is determined, open the valve 1 705, the oil flows into the liquid outlet pipe 701, the liquid collecting pipe 702 and the liquid discharge pipe 1 708, close the valve 1 705, open the valve 2 706, release the oil in the liquid pipe 701, the liquid collecting pipe 702 and the liquid discharge pipe 1 708, and then complete the quantitative measurement of the oil.

[0058] Embodiment 7

[0059] like Figure 1-16 As shown, the connecting pipe 1 is provided with a pressure relief and explosion-proof component 8, which includes a pressure relief pipe 801, which is fixed on the side wall of the connecting pipe 1 and communicated with the inside of the connecting pipe 1, a second liquid discharge pipe 802 is fixed at the lower end of the pressure relief pipe 801, a bracket 803 is fixed at the end of the pressure relief pipe 801, a second piston 804 is slidably connected inside the pressure relief pipe 801, the second piston 804 is fixedly connected to a push rod 805, the second piston 804 is fixedly connected to one end of a fourth spring 806, the other end of the fourth spring 806 is fixed on a fixed disk 807, the fixed disk 807 is rotatably connected to a spring push plate 808, the spring push plate 808 is threadedly connected to the pressure relief pipe 801, a long tube 809 is fixed at the center of the spring push plate 808, the fixed disk 807 is rotatably connected to the long tube 809, the push rod 805 is slidably connected to the long tube 809, and the end of the long tube 809 is fixedly connected to a rotating wheel 810;

[0060] The push rod 805 is fixedly connected to the long rod 811, the long rod 811 is fixedly connected to the bent rod 812, a pointer is provided at the end of the bent rod 812, a calibration line 815 is provided on the rotating wheel 810, a first scale line 813 and a second scale line 814 are provided on the bracket 803, the pointer points to the scale position on the first scale line 813, the calibration line 815 corresponds to the scale position on the second scale line 814, the bracket 803 is fixedly connected to the alarm switch 816, the alarm switch 816 is electrically connected to the alarm 818 through the transmission line 817, and the alarm 818 is fixed at the lower end of the bracket 803;

[0061] The working principle of the above technical solution is: the oil in the connecting pipe 1 squeezes the piston 2 804 to overcome the tension of the spring 4 806 and move in the pressure relief pipe 801, driving the spring 4 806 to be compressed, driving the push rod 805 and the long rod 811 to move, driving the bent rod 812 to move, and the scale on the first scale line 813 at the front end of the bent rod 812 is the oil pressure value in the connecting pipe 1 at this time, and then the pressure relief explosion-proof component 8 has the function of measuring the oil pressure value;

[0062] When the oil pressure value in the connecting pipe 1 continues to increase, the extrusion piston 2 804 continues to move forward, driving the spring 4 806 to continue to be compressed. When the oil pressure reaches the preset value that the connecting pipe 1 and the threaded sleeve 2 can withstand, the piston 2 804 moves in the pressure relief pipe 801 and passes over the upper end of the drain pipe 2 802. The connecting pipe 1 is connected with the drain pipe 2 802 through the pressure relief pipe 801. The oil in the connecting pipe 1 is discharged through the drain pipe 2 802, thereby reducing the oil pressure in the connecting pipe 1. The lower end of the drain pipe 2 802 is placed in the oil receiving barrel to facilitate the reception of the oil. When the piston 2 804 moves in the pressure relief pipe 801 and passes over the upper end of the drain pipe 2 802, the push rod 805 moves forward to hit the alarm switch 816. The alarm switch 816 is turned on and an alarm is sounded through the alarm 818, even if personnel come to repair at the same time;

[0063] In the initial state, when there is no oil in the connecting pipe 1, the rotating wheel 810 is rotated to drive the long tube 809 to rotate, drive the spring push plate 808 to rotate, and the spring push plate 808 and the fixed plate 807 rotate, drive the spring push plate 808 to move forward or backward in the pressure relief pipe 801, and the spring push plate 808 moves with the spring push plate 808, thereby changing the elastic force of the spring four 806 in the initial state, and thereby changing the oil pressure required when the piston two 804 moves in the pressure relief pipe 801 and passes over the upper end of the liquid discharge pipe two 802, thereby changing the preset oil pressure value of the pressure relief. Through this adjustment, the ability of different connecting pipes 1 to withstand oil pressure can be adapted. The calibration line 815 on the rotating wheel 810 corresponds to the second scale line 814, and the adjustment position of the rotating wheel 810 can be checked.

[0064] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A casing gas-tight threaded joint for an oil well wellhead casing head, characterized in that: The invention comprises a connecting pipe (1), wherein the upper and lower ends of the connecting pipe (1) are respectively connected to an upper threaded joint (11) and a lower threaded joint (12); two threaded sleeves (2) are slidably connected to the connecting pipe (1); the upper threaded joint (11) and the lower threaded joint (12) are respectively threadedly connected to the two threaded sleeves (2); and air bags (3) are provided between the two threaded sleeves (2) and the connecting pipe (1); A pressure measuring component (5) is provided on the other side of the airbag (3), and the pressure measuring component (5) includes a second support tube (501), the airbag (3) is fixedly connected to the second support tube (501), the airbag (3) is communicated with the second support tube (501), a piston (502) is slidably connected inside the second support tube (501), the piston (502) is fixedly connected to the piston rod (503), the piston rod (503) is slidably connected to the second support tube (501), and a spring (504) is provided between the second support tube (501) and the piston (502); The piston rod (503) is provided with scale lines, the end of the second support cylinder (501) is threadedly connected with the second cover cap (505), and the second cover cap (505) is in a transparent state; The connecting pipe (1) is provided with a pressure relief and explosion-proof component (8), the pressure relief and explosion-proof component (8) comprising a pressure relief pipe (801), the pressure relief pipe (801) being fixed on the side wall of the connecting pipe (1) and being in communication with the interior of the connecting pipe (1), a second liquid discharge pipe (802) being fixed at the lower end of the pressure relief pipe (801), a bracket (803) being fixed at the end of the pressure relief pipe (801), a second piston (804) being slidably connected inside the pressure relief pipe (801), the second piston (804) being fixedly connected to a push rod (805), and the second piston (804) The spring (806) is fixedly connected to one end of the spring (806), the other end of the spring (806) is fixed on the fixed disk (807), the fixed disk (807) is rotatably connected to the spring push plate (808), the spring push plate (808) is threadedly connected to the pressure relief pipe (801), a long tube (809) is fixed at the center of the spring push plate (808), the fixed disk (807) is rotatably connected to the long tube (809), the push rod (805) is slidably connected to the long tube (809), and the end of the long tube (809) is fixedly connected to the rotating wheel (810); The push rod (805) is fixedly connected to the long rod (811), the long rod (811) is fixedly connected to the bent rod (812), a pointer is provided at the end of the bent rod (812), a calibration line (815) is provided on the rotating wheel (810), a first scale line (813) and a second scale line (814) are provided on the bracket (803), the pointer points to the scale position on the first scale line (813), the calibration line (815) corresponds to the scale position on the second scale line (814), the bracket (803) is fixedly connected to the alarm switch (816), the alarm switch (816) is electrically connected to the alarm (818) through the transmission line (817), and the alarm (818) is fixed at the lower end of the bracket (803).

2. The casing gas-tight threaded joint for an oil wellhead casing head according to claim 1, characterized in that: A sealing ring 1 (9) is provided at the connection point between the connecting pipe (1) and the threaded sleeve (2), and a sealing ring 2 (10) is provided at the connection points between the upper threaded joint (11) and the lower threaded joint (12) and the connecting pipe (1).

3. The casing gas-tight threaded joint for an oil well wellhead casing head according to claim 1, characterized in that: A pressurizing component (4) is provided on one side of the airbag (3), and the pressurizing component (4) includes a support tube (401). The airbag (3) is fixedly connected to the support tube (401), and the airbag (3) is communicated with the support tube (401). An air intake pipe (402) is slidably connected inside the support tube (401), and four air intake holes (403) are provided on the air intake pipe (402). A spring (404) is provided between the support tube (401) and the air intake pipe (402), and the end of the support tube (401) is threadedly connected to a cap (405).

4. The casing gas-tight threaded joint for an oil wellhead casing head according to claim 1, characterized in that: A support component (6) is fixed in the middle of the connecting tube (1), and the support component (6) comprises a fixing ring (601). The fixing ring (601) is fixed in the middle of the connecting tube (1), and the fixing ring (601) is slidably connected to an inner ring frame (603). A plurality of springs (602) are provided between the fixing ring (601) and the inner ring frame (603).

5. The casing gas-tight threaded joint for an oil wellhead casing head according to claim 4, characterized in that: The inner ring frame (603) is rotatably connected to the plurality of upper leg frames (604), the upper leg frames (604) are rotatably connected to the turntable (605), an outer tube (606) and a screw rod (607) are fixed on the turntable (605), the outer tube (606) is slidably connected to the lower leg frame (608), the screw rod (607) is threadedly connected to the lower leg frame (608), and the lower end of the lower leg frame (608) is rotatably connected to a support plate (609).

6. The casing gas-tight threaded joint for an oil well wellhead casing head according to claim 1, characterized in that: The connecting tube (1) is provided with a quantitative sampling component (7), the quantitative sampling component (7) comprising a liquid outlet pipe (701), the liquid outlet pipe (701) being fixed on the side wall of the connecting tube (1) and being communicated with the interior of the connecting tube (1), the liquid outlet pipe (701) being slidably connected to a liquid collecting pipe (702), a fixing ring (703) being rotatably connected to a second screw rod (707), the second screw rod (707) being threadedly connected to the liquid collecting pipe (702), a scale (704) being fixed at the end of the liquid collecting pipe (702), the scale (704) being slidably connected to the fixing ring (703), a liquid discharge pipe (708) being fixed at the lower end of the liquid collecting pipe (702), a valve (705) being provided in the liquid outlet pipe (701), and a valve (706) being provided in the first liquid discharge pipe (708).

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