Oil and gas well annulus pressure regulating device and pipe string

Abstract

The present invention provides an oil and gas well annulus pressure regulating device and a pipe string, the oil and gas well annulus pressure regulating device comprises a connecting nipple and a cover body surrounding the outside of the connecting nipple; a chamber with a certain accommodation space is formed between the inner wall of the cover body and the outer wall of the connecting nipple, a piston is arranged in the chamber, the piston is movably connected between the inner wall of the cover body and the outer wall of the connecting nipple, and reciprocates along the axial direction of the connecting nipple; the piston comprises a first piston and a second piston, the first piston and the second piston are arranged relatively along the axial direction of the connecting nipple, and the chamber is divided into a first space, a second space and a third space; at least two elastic members connected to the first piston and the second piston at the same time are arranged in the first space, and a first connecting port for connecting the second space with the annulus in the well and a second connecting port for connecting the third space with the annulus in the well are opened on the cover body. The present invention can reduce the labor intensity of the staff.

Description

Technical Field

[0001] The invention relates to the technical field of annular space pressure control engineering, and in particular to an annular space pressure regulating device and a pipe string for an oil and gas well. Background Art

[0002] During the drilling and completion process, in order to separate different geological strata and prevent the wellbore from collapsing due to different formation pressures, one or more layers of casing cementing are required. Each layer of casing is cemented with cement, and the annular space between each layer of casing is filled with annular protection fluid. The pressure of the annular space between each layer of casing is the annular pressure. Since there may be natural gas or annular protection fluid between the annuli, the pressure is generated by thermal expansion and contraction due to the temperature during production. Annular pressure control is very important in the development of high-yield and high-pressure natural gas wells. Excessive annular pressure may cause casing rupture, natural gas to enter the surface, and cause serious blowout accidents.

[0003] In the prior art, the method of buffering the annular pressure in the well is usually to control the annular pressure by operating the valve connected to the casing on the Christmas tree, opening the Christmas tree valve to absorb the pressure, and buffering the annular pressure in the well. However, this method greatly increases the labor intensity of the staff, and is prone to unsafe accidents such as casing rupture due to human negligence or improper operation. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an oil and gas well annulus pressure regulating device and a pipe string. The oil and gas well annulus pressure regulating device has a simple structure and is easy to operate, which can reduce the labor intensity of the staff and improve the safety factor during the construction process.

[0005] In order to achieve the above-mentioned technical effects, on the one hand, the present invention provides an annulus pressure regulating device for an oil and gas well, which is used to regulate the pressure of the annulus in the well, comprising a connecting short joint and a cover body surrounding the outside of the connecting short joint; a chamber with a certain accommodating space is formed between the inner wall of the cover body and the outer wall of the connecting short joint, and a piston is arranged in the chamber, and the piston is movably connected between the inner wall of the cover body and the outer wall of the connecting short joint, and moves back and forth along the axial direction of the connecting short joint.

[0006] The piston comprises a first piston and a second piston, the first piston and the second piston are arranged opposite to each other along the axial direction of the connecting nipple, and the first piston and the second piston divide the chamber into a first space, a second space and a third space; at least two elastic members are arranged in the first space, one end of the elastic member is connected to the first piston, and the other end of the elastic member is connected to the second piston; and

[0007] The cover body is provided with a first communication port for connecting the second space with the annulus in the well and a second communication port for connecting the third space with the annulus in the well.

[0008] In the above-mentioned oil and gas well annulus pressure regulating device, optionally, the first space is filled with a compressible medium for absorbing pressure.

[0009] In the above-mentioned annulus pressure regulating device for oil and gas wells, it is optional that a blocking block is arranged on the outer wall of the connecting short section and / or on the first side wall of the cover body away from the connecting short section; the blocking block includes a first blocking block and a second blocking block, the first blocking block is arranged in the second space and close to the first connecting port, and is used to limit the moving range of the first piston in the chamber; the second blocking block is arranged in the third space and close to the second connecting port, and is used to limit the moving range of the second piston in the chamber.

[0010] In the above-mentioned oil and gas well annulus pressure regulating device, optionally, it also includes: a heater; the heater is arranged in the first space and is used to heat the compressible medium.

[0011] In the above-mentioned oil and gas well annulus pressure regulating device, optionally, it also includes: a first control device; the first control device is connected to the heater and is used to control the opening and closing of the heater.

[0012] In the above-mentioned oil and gas well annulus pressure regulating device, optionally, it also includes: a pressure measuring device; the pressure measuring device is arranged in the first space and is electrically connected to the first control device.

[0013] When the pressure value measured by the pressure measuring device is less than a preset pressure value, the first control device controls the heater to turn on; when the pressure value measured by the pressure measuring device is greater than the preset pressure value, the first control device controls the heater to turn off.

[0014] In the above-mentioned oil and gas well annulus pressure regulating device, optionally, the chamber also includes: at least two guide rods; the elastic member is sleeved on the guide rod; one end of the guide rod is connected to the second side wall of the cover body, and the other end of the guide rod is connected to the third side wall of the cover body; the guide rod is slidably connected to the first piston and the second piston.

[0015] In the above-mentioned oil and gas well annulus pressure regulating device, it is optional that the elastic member includes a first elastic member and a second elastic member; a fixing portion is provided on the guide rod, one end of the first elastic member is connected to the first piston, and the other end of the first elastic member is connected to the fixing portion; one end of the second elastic member is connected to the second piston, and the other end of the second elastic member is connected to the fixing portion.

[0016] In the above-mentioned oil and gas well annulus pressure regulating device, optionally, the chamber also includes: a telescopic mechanism; the telescopic mechanism is arranged in the first space, and the telescopic mechanism includes a second control device, a first telescopic component and a second telescopic component, the second control device is arranged on the first side wall, one end of the first telescopic component is connected to the second control device, and the other end of the first telescopic component faces the first piston; one end of the second telescopic component is connected to the second control device, and the other end of the second telescopic component faces the second piston.

[0017] On the other hand, the present invention further provides a pipe string, which at least comprises an oil pipe and the above-mentioned oil and gas well annulus pressure regulating device.

[0018] Both ends of the connecting nipple of the oil and gas well annular space pressure regulating device are respectively provided with connecting parts, and the connecting parts are used to connect the oil pipe so that the connecting nipple is communicated with the oil pipe.

[0019] The present invention provides an annulus pressure regulating device and a tubing string for oil and gas wells. The annulus pressure regulating device for oil and gas wells is configured to connect a connecting short joint to an oil pipe. As the oil pipe is lowered into the well, the second space and the third space in the chamber are connected to the annulus in the well through the first connecting port and the second connecting port, respectively, so that the first piston and the second piston in the chamber move in a relatively close direction when the annulus pressure is relatively large, and at the same time compress the elastic member and / or the compressible medium in the first space, and transfer part of the annulus pressure to the compressible medium through the piston, thereby buffering the annulus pressure and protecting the safety of the wellbore. Therefore, the annulus pressure regulating device for oil and gas wells of the embodiment of the present invention has a simple structure, is easy to implement, and has a low investment cost. In the process of buffering the annulus pressure in the well, it is only necessary to lower the annulus pressure regulating device for oil and gas wells into the well along with the oil pipe, which is simple to operate and reduces the labor intensity of the staff.

[0020] The construction of the present invention and other objects and advantageous effects thereof will become more apparent through the description of the preferred embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A schematic structural diagram of an oil and gas well annulus pressure regulating device provided by an embodiment of the present invention;

[0023] Figure 2 A schematic structural diagram of another oil and gas well annulus pressure regulating device provided by an embodiment of the present invention;

[0024] Figure 3 A schematic structural diagram of another oil and gas well annulus pressure regulating device provided by an embodiment of the present invention;

[0025] Figure 4 A schematic structural diagram of another oil and gas well annulus pressure regulating device provided by an embodiment of the present invention;

[0026] Figure 5 A schematic structural diagram of another oil and gas well annulus pressure regulating device provided by an embodiment of the present invention;

[0027] Figure 6 A schematic structural diagram of another oil and gas well annulus pressure regulating device provided in an embodiment of the present invention.

[0028] Description of reference numerals:

[0029] 100- Oil and gas well annulus pressure regulating device;

[0030] 1-Connect the short section;

[0031] 11-connecting part;

[0032] 2-Hood body;

[0033] 21- a first side wall;

[0034] 22- a second side wall;

[0035] 23- third side wall;

[0036] 3- Chamber;

[0037] 31-First space;

[0038] 32- Second space;

[0039] 321-first communication port;

[0040] 33- Third Space;

[0041] 331- second communication port;

[0042] 10-Piston;

[0043] 101 - first piston;

[0044] 102 - second piston;

[0045] 20- elastic member;

[0046] 201-first elastic member;

[0047] 202- second elastic member;

[0048] 30-block;

[0049] 301-first blocking block;

[0050] 302- second blocking block;

[0051] 40-heater;

[0052] 50- first control device;

[0053] 60-pressure measuring equipment;

[0054] 70-guide rod;

[0055] 701-fixed part;

[0056] 80- telescopic mechanism;

[0057] 801- second control device;

[0058] 802-first telescopic component;

[0059] 803-Second telescopic component. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the embodiment of the present invention will be described in more detail below in conjunction with the drawings in the preferred embodiments of the present invention. In the drawings, the same or similar reference numerals throughout represent the same or similar parts or parts with the same or similar functions. The described embodiments are part of the embodiments of the present invention, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limitations on the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The embodiments of the present invention are described in detail below in conjunction with the drawings.

[0061] 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, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] Embodiment 1

[0063] Figure 1 A schematic structural diagram of an oil and gas well annulus pressure regulating device provided in an embodiment of the present invention. Figure 2 A schematic structural diagram of another oil and gas well annulus pressure regulating device provided in an embodiment of the present invention. Figure 3 A schematic structural diagram of another oil and gas well annulus pressure regulating device provided in an embodiment of the present invention. Figure 4 A schematic structural diagram of another oil and gas well annulus pressure regulating device provided in an embodiment of the present invention. Figure 5 A schematic structural diagram of another oil and gas well annulus pressure regulating device provided in an embodiment of the present invention. Figure 6 A schematic structural diagram of another oil and gas well annulus pressure regulating device provided in an embodiment of the present invention.

[0064] like Figure 1 As shown, a first embodiment of the present invention provides an annulus pressure regulating device 100 for an oil and gas well, which is used to regulate the pressure of the annulus in the well, and includes a connecting pup joint 1 and a cover body 2 surrounding the outside of the connecting pup joint 1, and a chamber 3 with a certain accommodating space is formed between the inner wall of the cover body 2 and the outer wall of the connecting pup joint 1.

[0065] The cover body 2 may surround the outer wall of the connecting short section 1 for one circle to form a chamber 3 with a complete annular space. Alternatively, the cover body 2 may surround the outer wall of the connecting short section 1 for less than one circle to form a chamber 3 with a semi-annular space.

[0066] A piston 10 is disposed in the chamber 3 . The piston 10 is movably connected between the inner wall of the cover 2 and the outer wall of the connecting nipple 1 , and reciprocates along the axial direction of the connecting nipple 1 .

[0067] The piston 10 includes a first piston 101 and a second piston 102 , which are arranged opposite to each other along the axial direction of the connecting short section 1 , and the first piston 101 and the second piston 102 separate the chamber 3 into a first space 31 , a second space 32 and a third space 33 .

[0068] At least two elastic members 20 are disposed in the first space 31, one end of the elastic member 20 is connected to the first piston 101, and the other end of the elastic member 20 is connected to the second piston 102. When the first piston 101 and the second piston 102 are close to each other, the elastic member 20 exerts a force on the first piston 101 and the second piston 102 to move them away from each other.

[0069] Moreover, the cover body 2 is provided with a first connecting port 321 for connecting the second space 32 with the annulus in the well and a second connecting port 331 for connecting the third space 33 with the annulus in the well. When the annulus pressure regulating device 100 of the oil and gas well is lowered into the well along with the oil pipe, the first connecting port 321 and the second connecting port 331 are respectively connected with the annulus in the well.

[0070] Furthermore, a compressible medium for absorbing pressure is filled in the first space 31. Specifically, the compressible medium may be gas or elastic material, etc., which can absorb pressure when compressed to achieve pressure buffering. The present invention does not limit the specific type of the compressible medium, nor is it limited to the above examples.

[0071] Since the pressure of gas is relatively easy to measure and control, as a preferred embodiment, the compressible medium can be gas. Therefore, the compressible property of gas can be used to absorb part of the pressure of the annular space. In actual use, according to the pressure value that the annular space pressure should not exceed, the first space 31 of the chamber 3 is filled with gas of a preset pressure value, so that when the annular space pressure is greater than the pressure value that should not be exceeded, the first piston 101 and the second piston 102 in the compression chamber 3 are relatively close, and part of the pressure of the annular space pressure is transmitted to the gas in the first space 31, thereby buffering the annular space pressure.

[0072] As the gas for energy storage buffering, for example, the gas may be nitrogen.

[0073] It should be noted that the main function of the elastic member 20 is to reset the first piston 101 and the second piston 102, and the elastic member 20 also has a certain pressure buffering function. Therefore, in order to ensure that the compressible medium can further achieve pressure buffering on the basis of the pressure buffering of the elastic member 20, as a preferred embodiment, the compressible critical pressure value of the compressible medium needs to be greater than the compressible critical pressure value of the elastic member 20.

[0074] It should be noted that when the first space 31 of the chamber 3 is filled with gas, one of the first piston 101 or the second piston 102 can be installed in the chamber 3 first, and then after a certain pressure of gas is filled, the other of the first piston 101 or the second piston 102 can be installed in the chamber 3, so that the filled gas is located in the first space 31 between the first piston 101 and the second piston 102. Among them, the chamber 3 can be designed as a space with openings at both ends formed by the cover body 2 surrounding the outer wall of the connecting short section 1, and the outer wall of the connecting short section 1. For example, sealing covers can be connected to the openings at both ends, respectively, or it can be designed in other forms, as long as it can meet the requirements of the chamber 3 to be able to load components such as the elastic member 30 and the piston 20. The present invention does not limit the specific design form of the chamber 3, nor is it limited to the above examples.

[0075] like Figure 2 As shown, in this embodiment, a blocking block 30 is provided on the outer wall of the connecting short section 1 and / or on the first side wall 21 of the cover body 2 away from the connecting short section 1 .

[0076] The blocking block 30 may be provided only on the outer wall of the connecting nipple 1, the blocking block 30 may be provided only on the first side wall 21 of the cover body 2 away from the connecting nipple 1, or the blocking block 30 may be provided on both the outer wall of the connecting nipple 1 and the first side wall 21 of the cover body 2 away from the connecting nipple 1. When the blocking block 30 is provided on both the outer wall of the connecting nipple 1 and the first side wall 21 of the cover body 2 away from the connecting nipple 1, the blocking of the piston 20 will be more balanced.

[0077] Specifically, the blocking block 30 includes a first blocking block 301 and a second blocking block 302. The first blocking block 301 is disposed in the second space 32 and close to the first communication port 321, and is used to limit the range of movement of the first piston 101 in the chamber 3. The second blocking block 302 is disposed in the third space 33 and close to the second communication port 331, and is used to limit the range of movement of the second piston 102 in the chamber 3. In other words, the first piston 101 and the second piston 102 will not block the first communication port 321 and the second communication port 331 when they are close to or away from each other.

[0078] It should be noted that the structure for limiting the range of movement of the first piston 101 and the second piston 102 (for example, the first blocking block 301 and the second blocking block 302) is sufficient as long as the first piston 101 and the second piston 102 do not block the first connecting port 321 and the second connecting port 331. The present invention does not limit the structure for limiting the range of movement of the first piston 101 and the second piston 102, nor is it limited to the above-mentioned examples.

[0079] In actual use, the oil and gas well annulus pressure regulating device 100 is connected to the oil pipe through the connecting short section 1, and as the oil pipe is lowered into the well, the second space 32 and the third space 33 in the chamber 3 are connected to the annulus in the well through the first connecting port 321 and the second connecting port 331 respectively. When the annulus pressure is greater than the compressible critical pressure value of the compressible medium in the first space 31 (at this time, the compressible critical pressure value of the compressible medium is greater than the compressible critical pressure value of the elastic member 20), the first piston 101 and the second piston 102 move in a direction of relative convergence, and the second space 32 and the third space 33 gradually become smaller, while compressing the elastic member 20 and the compressible medium between the first piston 101 and the second piston 102. The elastic member 20 and the compressible medium absorb part of the annulus pressure (the pressure is mainly absorbed by the compressible medium), which plays a buffering role on the annulus pressure, thereby protecting the safety of the wellbore.

[0080] like Figure 3 As shown, the oil and gas well annulus pressure regulating device 100 provided in the embodiment of the present invention further includes: a heater 40, which is arranged in the first space 31 and is used to heat the compressible medium so that the compressible medium expands and pushes the first piston 101 and the second piston 102.

[0081] As an optional implementation, it further includes: a first control device 50 , which is connected to the heater 40 and is used to control the opening and closing of the heater 40 .

[0082] It should be noted that, by setting the heater 40 and the first control device 50, the oil and gas well annulus pressure regulating device 100 can have the function of compensating the annulus. Specifically, its working principle is: a pressure sensor (not shown in the figure) can be set in the annulus in the well, and the annulus pressure is detected by the pressure sensor. When the annulus pressure is low, the heater 40 is started by the first control device 50 to heat the gas in the first space 31. The gas expands due to the heat, pushing the first piston 101 and the second piston 102 in the chamber 3 to move in a relatively distant direction, thereby compensating the annulus; when the annulus pressure reaches the required pressure value, the heater 40 is turned off by the first control device 50 to stop compensating the pressure.

[0083] It should be noted that the first control device 50 can be designed for manual control or automatic control. The oil and gas well annulus pressure regulating device 100 in the embodiment of the present invention can replenish the annulus pressure during large-volume injection operations, improve the safety factor of the oil casing, and thus ensure the integrity of the wellbore.

[0084] As an optional implementation, it further includes: a pressure measuring device 60 ; the pressure measuring device 60 is disposed in the first space 31 and is electrically connected to the first control device 50 .

[0085] When the pressure value measured by the pressure measuring device 60 is less than the preset pressure value, the first control device 50 controls the heater 40 to turn on; when the pressure value measured by the pressure measuring device 60 is greater than the preset pressure value, the first control device 50 controls the heater 40 to turn off.

[0086] The pressure measuring device 60 may be a pressure sensor or other gas pressure measuring instrument, etc., and the first control device 50 is used to control the opening and closing of the heater 40 according to the relationship between the pressure value measured by the pressure measuring device 60 and the preset pressure value. The preset pressure value may be set according to the lower limit value of the annular space pressure.

[0087] In actual use, the pressure measuring device 60 is arranged in the first space 31 of the chamber 3. The pressure measuring device 60 is arranged in the first space 31 of the chamber 3, and can measure the pressure of the gas in the first space 31, which changes with the change of the annular pressure, that is, when the annular pressure is large, the first piston 101 and the second piston 102 will compress the gas in the first space 31, so that the gas pressure in the first space 31 increases, and when the annular pressure is small, the gas in the first space 31 is no longer compressed, and the pressure decreases until the annular pressure on the first piston 101 and the second piston 102 is balanced with the pressure in the first space 31. Specifically, a preset pressure value is set. When the gas pressure value measured by the pressure measuring device 60 is less than the preset pressure value, it indicates that the annular pressure is low and pressure compensation is required. The heater 40 can be started through the first control device 50 to heat and expand the gas in the first space 31 to compensate the annular pressure. When the gas pressure value measured by the pressure measuring device 60 is greater than or equal to the preset pressure value, it indicates that the annular pressure increases and pressure compensation is not required. The heater 40 can be turned off through the first control device 50 to stop pressure compensation. The control of the annular pressure by turning on or off the heater 40 through the first control device 50 can greatly reduce the labor intensity of the staff.

[0088] Furthermore, if Figure 4 As shown, the chamber 3 may further include: at least two guide rods 70. The elastic member 20 is sleeved on the guide rod 70; one end of the guide rod 70 is connected to the second side wall 22 of the cover body 2, and the other end of the guide rod 70 is connected to the third side wall 23 of the cover body 2; the guide rod 70 is slidably connected to the first piston 101 and the second piston 102.

[0089] Among them, the first piston 101 and the second piston 102 can move along the guide rod 70, and the guide rod 70 guides the first piston 101 and the second piston 102. An elastic member 20 is sleeved on the guide rod 70, and the elastic member 20 can also play a balancing and supporting role for the first piston 101 and the second piston 102.

[0090] As an optional implementation, the elastic member 20 may be a compression spring, which has a simple structure and low cost.

[0091] As an optional implementation, Figure 5 As shown, the elastic member 20 includes a first elastic member 201 and a second elastic member 202; a fixing portion 701 is provided on the guide rod 70, one end of the first elastic member 201 is connected to the first piston 101, and the other end of the first elastic member 201 is connected to the fixing portion 701; one end of the second elastic member 202 is connected to the second piston 102, and the other end of the second elastic member 202 is connected to the fixing portion 701.

[0092] It should be noted that the fixing portion 701 may be a connecting hole or other structure located in the middle of the guide rod 70 . The present invention does not limit the specific structure of the fixing portion 701 , nor is it limited to the above example.

[0093] In this embodiment, if Figure 6 As shown, the chamber 3 may also include: a telescopic mechanism 80; the telescopic mechanism 80 is arranged in the first space 31, the telescopic mechanism 80 includes a second control device 801, a first telescopic component 802 and a second telescopic component 803, the second control device 801 is arranged on the first side wall 21, one end of the first telescopic component 802 is connected to the second control device 801, and the other end of the first telescopic component 802 is toward the first piston 101; one end of the second telescopic component 803 is connected to the second control device 801, and the other end of the second telescopic component 803 is toward the second piston 102.

[0094] When the first telescopic component 802 and the second telescopic component 803 extend, the first piston 101 and the second piston 102 are pushed away from each other. When the first telescopic component 802 and the second telescopic component 803 retract, the first telescopic component 802 and the second telescopic component 803 are separated from the first piston 101 and the second piston 102. By arranging the telescopic mechanism 80 in the first space 31, when annular pressure replenishment is required, the first telescopic component 802 and the second telescopic component 803 are controlled by the second control device 801 to extend toward the first piston 101 and the second piston 102, so that the first telescopic component 802 and the second telescopic component 803 push the first piston 101 and the second piston 102 to compress the fluid in the annular space and replenish the pressure of the annular space; when annular pressure replenishment is not required, the first telescopic component 802 and the second telescopic component 803 are controlled by the second control device 801 to retract, so that the first telescopic component 802 and the second telescopic component 803 do not contact the piston.

[0095] It should be noted that the telescopic mechanism 80 may be located in the first space 31 at a position that does not interfere with other components such as the elastic member 20 .

[0096] The oil and gas well annulus pressure regulating device provided in the first embodiment of the present invention is connected to the oil pipe through a connecting short joint. As the oil pipe is lowered into the well, the second space and the third space in the chamber are connected to the annulus in the well through the first connecting port and the second connecting port respectively, so that the first piston and the second piston in the chamber move in a relatively close direction when the annulus pressure is large, and at the same time compress the elastic member and / or the compressible medium in the first space, and transfer part of the annulus pressure to the compressible medium through the piston, thereby buffering the annulus pressure and protecting the safety of the wellbore. Therefore, the oil and gas well annulus pressure regulating device of the embodiment of the present invention has a simple structure, is easy to implement, and has a low investment cost. In the process of buffering the annulus pressure in the well, it is only necessary to lower the oil and gas well annulus pressure regulating device into the well along with the oil pipe, which is simple to operate and reduces the labor intensity of the staff.

[0097] Embodiment 2

[0098] On the basis of the above-mentioned first embodiment, the second embodiment of the present invention provides a pipe string, which at least includes an oil pipe and the oil and gas well annulus pressure regulating device 100 in the above-mentioned first embodiment.

[0099] The two ends of the connecting nipple 1 of the annular space pressure regulating device 100 of the oil and gas well are respectively provided with connecting parts 11, and the connecting parts 11 are used to connect the oil pipe so that the connecting nipple 1 is connected with the oil pipe.

[0100] The connection parts 11 at both ends of the connecting nipple 1 can be flexibly designed according to the connection method with the oil pipe, for example, threaded connection or welding connection can be adopted. The present invention does not limit the connection method between the connecting nipple 1 and the oil pipe, nor is it limited to the above examples.

[0101] For example, the connection portion 11 of the connecting nipple 1 may be provided with an external thread, one end of the oil pipe may be provided with an internal thread, and the connecting nipple 1 and the oil pipe are connected by threads. This connection method is convenient for assembly and disassembly, and the connection is reliable.

[0102] It should be noted that, after the oil and gas well annulus pressure regulating device 100 is connected to the oil pipe through the connecting nipple 1, it can be lowered into the well along with the oil pipe.

[0103] In addition, other structures and principles of the oil and gas well annulus pressure regulating device 100 are the same as those of the above-mentioned embodiment 1 and will not be described in detail here.

[0104] The tubing string provided in the second embodiment of the present invention at least includes an oil pipe and an annulus pressure regulating device for an oil and gas well. The annulus pressure regulating device for an oil and gas well is connected to the oil pipe through a connecting short joint. As the oil pipe is lowered into the well, the second space and the third space in the chamber are connected to the annulus in the well through the first connecting port and the second flow port respectively, so that the first piston and the second piston in the chamber move in a relatively close direction when the annulus pressure is large, and at the same time compress the elastic member and / or the compressible medium in the first space, and part of the annulus pressure is transmitted to the compressible medium through the piston, thereby buffering the annulus pressure and protecting the safety of the wellbore. Therefore, the annulus pressure regulating device for an oil and gas well in the embodiment of the present invention has a simple structure, is easy to implement, and has a low investment cost. In the process of buffering the annulus pressure in the well, it is only necessary to lower the annulus pressure regulating device for the oil and gas well into the well along with the oil pipe, which is simple to operate and reduces the labor intensity of the staff.

[0105] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside" 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 position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In the description of the present invention, "plurality" means two or more, unless otherwise precisely and specifically specified.

[0106] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An annulus pressure regulating device for oil and gas wells, used for regulating the annulus pressure in the well, characterized in that: The invention comprises a connecting nipple and a cover body surrounding the outside of the connecting nipple; a chamber with a certain accommodation space is formed between the inner wall of the cover body and the outer wall of the connecting nipple, a piston is arranged in the chamber, and the piston is movably connected between the inner wall of the cover body and the outer wall of the connecting nipple, and reciprocates along the axial direction of the connecting nipple; The piston comprises a first piston and a second piston, the first piston and the second piston are arranged opposite to each other along the axial direction of the connecting nipple, and the first piston and the second piston divide the chamber into a first space, a second space and a third space; at least two elastic members are arranged in the first space, one end of the elastic member is connected to the first piston, and the other end of the elastic member is connected to the second piston; as well as The cover body is provided with a first communication port for connecting the second space with the annulus in the well and a second communication port for connecting the third space with the annulus in the well; The first space is filled with a compressible medium for absorbing pressure; Also included is a heater; the heater is disposed in the first space and is used to heat the compressible medium; A blocking block is arranged on the outer wall of the connecting short section and / or on the first side wall of the cover body away from the connecting short section; the blocking block includes a first blocking block and a second blocking block, the first blocking block is arranged in the second space and close to the first connecting port, and is used to limit the range of movement of the first piston in the chamber; the second blocking block is arranged in the third space and close to the second connecting port, and is used to limit the range of movement of the second piston in the chamber.

2. The oil and gas well annulus pressure regulating device according to claim 1, characterized in that: Also includes: a first control device; The first control device is connected to the heater and is used to control the opening and closing of the heater.

3. The oil and gas well annulus pressure regulating device according to claim 2, characterized in that: Also includes: A pressure measuring device; the pressure measuring device is arranged in the first space and is electrically connected to the first control device; When the pressure value measured by the pressure measuring device is less than a preset pressure value, the first control device controls the heater to turn on; When the pressure value measured by the pressure measuring device is greater than a preset pressure value, the first control device controls the heater to be turned off.

4. The oil and gas well annulus pressure regulating device according to claim 1, characterized in that: The chamber also includes: at least two guide rods; the elastic member is sleeved on the guide rods; one end of the guide rod is connected to the second side wall of the cover body, and the other end of the guide rod is connected to the third side wall of the cover body; the guide rod is slidably connected to the first piston and the second piston.

5. The oil and gas well annulus pressure regulating device according to claim 4, characterized in that: The elastic member includes a first elastic member and a second elastic member; a fixing portion is provided on the guide rod, one end of the first elastic member is connected to the first piston, and the other end of the first elastic member is connected to the fixing portion; one end of the second elastic member is connected to the second piston, and the other end of the second elastic member is connected to the fixing portion.

6. The oil and gas well annulus pressure regulating device according to claim 1, characterized in that: The chamber also includes: a telescopic mechanism; the telescopic mechanism is arranged in the first space, and the telescopic mechanism includes a second control device, a first telescopic component and a second telescopic component, the second control device is arranged on the first side wall, one end of the first telescopic component is connected to the second control device, and the other end of the first telescopic component faces the first piston; one end of the second telescopic component is connected to the second control device, and the other end of the second telescopic component faces the second piston.

7. A pipe column, characterized in that: At least comprises an oil pipe and an annulus pressure regulating device for an oil and gas well as claimed in any one of claims 1 to 6; Both ends of the connecting nipple of the oil and gas well annular space pressure regulating device are respectively provided with connecting parts, and the connecting parts are used to connect the oil pipe so that the connecting nipple is communicated with the oil pipe.

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