Underground pressure monitoring device based on wireless data transmission, its usage method and application

Abstract

The present invention relates to the technical field of downhole pressure monitoring, and specifically discloses a downhole pressure monitoring device based on wireless data transmission, its usage method, and application, including: a measuring column, in which an installation cavity communicating with the downhole environment is provided; a surrounding cylinder, arranged in the installation cavity, one end of the surrounding cylinder is an open end, and through grooves are provided on the side wall of the surrounding cylinder; a sealing cylinder for closing the open end of the surrounding cylinder, the sealing cylinder includes a flexible diaphragm, and a clamping groove opposite to the through groove is provided on its outer wall; a pressure sensor, arranged in the surrounding cylinder, and the measuring end of the pressure sensor contacts the flexible diaphragm; a sliding sealing assembly for realizing the sealed connection between the sealing cylinder and the surrounding cylinder. The present invention can protect the pressure sensor during the process of the pressure sensor collecting the well pressure, so as to reduce the influence of high temperature and corrosion on the service life of the pressure sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of downhole pressure monitoring, and particularly relates to a downhole pressure monitoring device based on wireless data transmission, its usage method, and application. Background Art

[0002] During the process of oil and gas extraction, downhole pressure monitoring is an important task. Downhole pressure monitoring mainly uses pressure sensors to collect the pressure in the well and transmits the collected pressure signals to the monitoring console on the ground through wired or wireless transmission methods to achieve real-time collection of the pressure in the well during the extraction process. The collected pressure can be used to assist in analyzing the changes in the downhole environment. Wireless transmission has obvious advantages over wired transmission in terms of flexibility, mobility, installation convenience, scalability, cost-effectiveness, and adaptability to complex environments. Therefore, wireless transmission is usually used for collecting downhole pressure signals.

[0003] Due to the complex downhole environment, there are usually problems such as high temperature, corrosion, and fluid or gas fluctuations. If the pressure sensor is directly placed in the downhole environment, the problems of high temperature, corrosion, and fluctuations will not only cause measurement errors but also affect the service life of the pressure sensor. In a downhole internal and external pressure monitoring device disclosed in CN202011202935.X, in order to facilitate the installation of the pressure gauge and enable the pressure gauge to be lowered into the well synchronously with the fracturing string, the pressure gauge is installed in the pressure monitoring chamber in the pressure transmission cylinder. However, the pressure gauge in its internal and external pressure monitoring chambers is still connected to the downhole environment through the internal pressure transmission hole and the external pressure transmission hole, and the pressure gauge therein will still be affected by the downhole environment. Summary of the Invention

[0004] The purpose of the present invention is to provide a downhole pressure monitoring device based on wireless data transmission, which can protect the pressure sensor during the process of collecting the downhole pressure by the pressure sensor to reduce the influence of high temperature and corrosion on the service life of the pressure sensor.

[0005] In addition, the present invention also provides a usage method and application of the above-mentioned downhole pressure monitoring device.

[0006] The present invention is achieved through the following technical solutions:

[0007] A downhole pressure monitoring device based on wireless data transmission includes:

[0008] A measuring column, in which an installation cavity communicating with the downhole environment is provided;

[0009] A surrounding cylinder, which is arranged in the installation cavity. One end of the surrounding cylinder is an open end, and through grooves are provided on the side wall of the surrounding cylinder;

[0010] The sealing cylinder is used to close the open end of the surrounding cylinder. The sealing cylinder includes a second cylinder body. A flexible diaphragm is arranged inside the second cylinder body, and a clamping groove opposite to the through groove is arranged on the outer wall of the second cylinder body;

[0011] A pressure sensor is arranged inside the surrounding cylinder, and the measuring end of the pressure sensor contacts the flexible diaphragm;

[0012] A sliding seal assembly is used to realize the sealed connection between the sealing cylinder and the surrounding cylinder. The sliding seal assembly includes a sliding positioning cylinder and a seal. The seal is arranged in the through groove, and the seal can perform radial displacement under the extrusion of the sliding positioning cylinder or the sealing cylinder. The sliding positioning cylinder is slidably arranged on the outer wall of the surrounding cylinder, and a convex portion is arranged on the inner wall of the sliding positioning cylinder. The convex portion is used to squeeze and fix the seal in the clamping groove.

[0013] In view of the problems of high temperature, corrosion and pressure fluctuation in the downhole working conditions (pressure fluctuation may be caused by the change of fluid or gas flow) in the present invention, the main inventive concept is to place a pressure sensor for collecting downhole pressure signals in a closed cavity, so that the pressure sensor is not directly exposed to the downhole environment, but reflects the downhole pressure by measuring the pressure received by the flexible diaphragm.

[0014] Specifically, in the present invention, the pressure sensor is in a closed cavity composed of a surrounding cylinder and a sealing cylinder, and the inside of the sealing cylinder is sealed by a flexible diaphragm. It can not only place the pressure sensor in a closed space to avoid its exposure to the well environment, but also measure the well environment pressure by measuring the pressure received by the flexible diaphragm. In the present invention, since the installation cavity is communicated with the downhole environment, the pressure in the installation cavity is the same as that in the well, and the flexible diaphragm is directly subjected to the pressure in the installation cavity, that is, the pressure received by the flexible diaphragm can be equivalent to the well pressure. In this way, the pressure sensor in the sealed cavity measures the well pressure, and can reduce the influence of high temperature and corrosion in the well environment on the service life of the pressure sensor, and the arranged installation cavity can reduce the influence of well pressure fluctuation on its measurement accuracy.

[0015] The present invention also takes into account that the downhole environment has a large pressure. In order to improve the stability of the sealing cylinder installed at the open end of the surrounding cylinder, the present invention realizes the sealed connection between the sealing cylinder and the surrounding cylinder through a sliding seal assembly, which can not only achieve sealing, but also improve the stability of the sealing cylinder; on the one hand, the sealing between the sealing cylinder and the surrounding cylinder is realized through their close contact, and on the other hand, when the convex portion squeezes and fixes the seal in the clamping groove, the seal can not only achieve further sealing, but also has a blocking effect on the downward displacement of the sealing cylinder. When the downhole pressure monitoring device is used for downhole pressure monitoring, since the installation cavity is communicated with the downhole environment, there is a large pressure in the installation cavity, that is, the sealing cylinder will be subjected to a large downward pressure. If the sealing is directly realized through the close contact between the sealing cylinder and the surrounding cylinder, the large pressure will cause the sealing cylinder to move downward, while the present invention can block the downward movement of the sealing cylinder through the arranged seal.

[0016] In summary, the present invention can protect the pressure sensor during the process of the pressure sensor collecting the well pressure, so as to reduce the influence of high temperature and corrosion on the service life of the pressure sensor.

[0017] In a preferred embodiment, the installation cavity has an open end, and the downhole pressure monitoring device further includes:

[0018] A sealing cover for closing the open end of the installation cavity, and a through hole communicating with the installation cavity is provided on the sealing cover.

[0019] In the present invention, an open end is provided at one end of the installation cavity, and the open end is closed by a sealing cover. A detachable connection is adopted between the sealing cover and the measuring column. It can not only realize the installation of components such as pressure sensors through the open end, but also avoid directly exposing components such as the sliding seal assembly, the cylinder and the sealing cylinder to the downhole environment. And a through hole for communicating the downhole environment and the installation cavity is provided on the sealing cover, which can make the pressure inside and outside the sealing cover consistent and will not affect the pressure monitoring of the downhole environment by the pressure sensor.

[0020] Preferably, a filter element is provided in the through hole in the present invention. The setting of the filter element can prevent impurities such as mud and sand in the well from entering the installation cavity, and further can avoid the damage of the flexible diaphragm by impurities such as mud and sand and problems such as pressure monitoring errors caused by impurities such as mud and sand.

[0021] In a preferred embodiment, the open end of the cylinder is arranged opposite to the sealing cover, and there is a spacing between the end of the open end of the cylinder and the sealing cover. A ring-shaped baffle is provided at the end of the open end of the cylinder, and an equal-pressure chamber is formed inside the ring-shaped baffle. The equal-pressure chamber communicates with the downhole environment through the through hole; or the end of the open end of the cylinder abuts against the sealing cover.

[0022] In the present invention, by providing a ring-shaped baffle or directly abutting the end of the open end of the cylinder against the sealing cover, it is to form an equal-pressure chamber in the installation cavity. The equal-pressure chamber is directly communicated with the downhole environment, which can not only meet the needs of pressure measurement, but also prevent downhole air flow or liquid from entering the space outside the equal-pressure chamber in the installation cavity, which is beneficial to protecting the sliding seal assembly.

[0023] In a preferred embodiment, a limiting plate is provided on the outer wall of the cylinder below the through groove; the sliding seal assembly further includes a first spring, and the first spring is arranged between the limiting plate and the convex portion.

[0024] By providing the first spring, the present invention can utilize the restoring force of the first spring to achieve the upward displacement of the sliding positioning cylinder, which can improve the convenience of the vertical sliding displacement of the sliding positioning cylinder. When the sliding positioning cylinder moves downward, the convex portion squeezes the first spring to cause compression of the first spring, thereby having a certain blocking effect on the downward movement of the sliding positioning cylinder and preventing the sliding positioning cylinder from excessively downward displacement. That is, the first spring designed in the present invention in cooperation with other components of the sliding seal assembly can not only limit the downward displacement of the sliding positioning cylinder, but also utilize its restoring force to push the sliding positioning cylinder upward, improving the convenience of operation.

[0025] In a preferred embodiment, the axial width of the through groove gradually increases from the inside to the outside, and the innermost end of the through groove is a circular hole; the seal is a sealing sphere or a sealing ellipsoid, the diameter of the sealing sphere is greater than the width of the surrounding cylinder; the major axis of the sealing ellipsoid is greater than the width of the surrounding cylinder.

[0026] With the shape and size of the through groove and the shape and size of the seal arranged as above in the present invention, not only can the seal achieve radial displacement under the extrusion of the sliding positioning cylinder or the sealing cylinder, but also the outer wall of the sealing sphere or the sealing ellipsoid is a curved surface, which is conducive to achieving the extrusion of the seal through the up and down displacement of the sliding positioning cylinder or the sealing cylinder.

[0027] In a preferred embodiment, both the innermost end and the outermost end of the through groove are circular holes, and the axial section of the inner wall of the through groove is a straight line or a curve.

[0028] In a preferred embodiment, the through groove is an equal-width strip-shaped groove, the seal is a strip-shaped seal body that is slidably and sealingly connected to the through groove, the length of the strip-shaped seal body is greater than the width of the surrounding cylinder, and both ends of the strip-shaped seal body are arc surfaces.

[0029] In a preferred embodiment, an outer guiding strip is provided on the outer wall of the surrounding cylinder; a first sliding groove that cooperates with the outer guiding strip is provided on the inner wall of the sliding positioning cylinder.

[0030] In a preferred embodiment, an inner guiding strip is provided on the inner wall of the surrounding cylinder, and a second sliding groove that cooperates with the inner guiding strip is provided on the outer wall of the second cylinder; the outer wall of the second cylinder is in close contact with the inner wall of the surrounding cylinder.

[0031] In a preferred embodiment, the second sliding groove is provided above the clamping groove.

[0032] The usage method of the downhole pressure monitoring device based on wireless data transmission includes the following steps:

[0033] S1. Fix the pressure sensor inside the surrounding cylinder so that the measuring end of the pressure sensor is located at the open end of the surrounding cylinder;

[0034] S2. Apply an axial thrust to the sliding positioning cylinder through an operating rod to move the sliding positioning cylinder downward, causing the protruding portion to move below the through groove;

[0035] S3. Insert the sealing cylinder into the open end of the surrounding cylinder. Under the extrusion of the second cylinder body, the sealing member moves radially outward. When the card slot moves to a position opposite to the through groove, stop moving the sealing cylinder. At this time, the measuring end of the pressure sensor abuts against the flexible diaphragm;

[0036] S4. Apply an axial pulling force to the sliding positioning cylinder through the operating rod to move the sliding positioning cylinder upward until the protruding portion moves to a position opposite to the through groove. At this time, under the extrusion of the protruding portion, the sealing member moves radially inward into the card slot.

[0037] The application of the downhole pressure monitoring device based on wireless data transmission is used for downhole pressure monitoring during oil or gas extraction.

[0038] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0039] In the present invention, a closed cavity for installing a pressure sensor is arranged in the measuring column, and the closed cavity is sealed by a sealing cylinder provided with a flexible diaphragm. At the same time, the outer space of the flexible diaphragm is communicated with the downhole space, so that the pressure received by the flexible diaphragm can reflect the downhole pressure. By abutting the measuring end of the pressure sensor against the flexible diaphragm, the pressure sensor directly uses the pressure received by the flexible diaphragm to reflect the downhole pressure, avoiding the problem of low service life caused by high temperature and corrosion in the downhole environment when the pressure sensor is directly exposed to the downhole environment to measure the downhole pressure. Moreover, the way of setting the sliding seal assembly to cooperate with the sealing cylinder in the present invention can not only realize the arrangement of the pressure sensor in a closed cavity, but also ensure good stability of the sealing cylinder under the well pressure. Description of the Drawings

[0040] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, form a part of this application, and do not limit the embodiments of the present invention. In the drawings:

[0041] Figure 1 It is a schematic structural diagram of the downhole pressure monitoring device in Embodiment 1 of the present invention;

[0042] Figure 2 It is an application schematic diagram of the downhole pressure monitoring device in Embodiment 1 of the present invention;

[0043] Figure 3 It is a schematic diagram of the sliding seal assembly not achieving sealing in Embodiment 1 of the present invention;

[0044] Figure 4It is a radial sectional view of the surrounding cylinder in Embodiment 1 of the present invention;

[0045] Figure 5 It is a schematic structural diagram of the sliding positioning cylinder of the present invention;

[0046] Figure 6 It is a schematic diagram of the sealing cylinder of the present invention;

[0047] Figure 7 It is a radial sectional view of the surrounding cylinder when the sliding sealing assembly in Embodiment 2 of the present invention fails to achieve sealing;

[0048] Figure 8 It is a radial sectional view of the surrounding cylinder after the sliding sealing assembly in Embodiment 2 of the present invention is sealed;

[0049] Figure 9 It is a radial sectional view of the surrounding cylinder after the sliding sealing assembly in Embodiment 3 of the present invention is sealed;

[0050] Figure 10 It is a radial sectional view of the surrounding cylinder after the sliding sealing assembly in Embodiment 4 of the present invention is sealed.

[0051] Marks and corresponding component names in the drawings:

[0052] 1 - Measuring column; 2 - Sealing cover; 3 - Surrounding cylinder; 4 - Sliding positioning cylinder; 5 - Sealing cylinder; 6 - Sealing member; 7 - First spring; 8 - Clamping mechanism; 9 - Buffer pad; 10 - Pressure sensor; 11 - Flange; 12 - Installation cavity; 13 - Equal - pressure cavity; 21 - Through - hole; 31 - Limiting plate; 32 - Outer guiding strip; 33 - Inner guiding strip; 35 - Through - slot; 34 - Annular baffle; 41 - First cylinder; 42 - Protruding part; 51 - Second cylinder; 52 - Flexible diaphragm; 81 - Adjusting bolt; 82 - Limiting cylinder; 83 - Fixed cross - bar; 100 - Downhole pressure monitoring device; 200 - Connecting cylinder; 300 - Guiding and anchoring device; 301 - Guiding block; 302 - Connecting rod; 303 - Slide block; 304 - Lead screw; 305 - Motor; 511 - Card slot. Detailed implementation manners

[0053] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. The illustrative embodiments and descriptions thereof of the present invention are only used to explain the present invention and do not limit the present invention. The following described embodiments are part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0054] In the following description, a number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those of ordinary skill in the art that the present invention may be practiced without these specific details. In other embodiments, well-known structures, materials, or methods have not been specifically described in order to avoid obscuring the present invention. Materials, instruments, reagents, etc. used in the following embodiments are commercially available unless otherwise specified. The technical means used in the embodiments are conventional means well-known to those skilled in the art unless otherwise specified.

[0055] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0056] Example 1:

[0057] As Figures 1 - 6 shown, in order to solve the problem of the low service life caused by the exposure of the pressure sensor of the existing downhole pressure monitoring device to the downhole environment, the present embodiment provides a downhole pressure monitoring device based on wireless data transmission, including:

[0058] Measuring column 1, inside which there is an installation cavity 12 communicating with the downhole environment; in specific use, a pressure sensor for collecting pressure signals can be installed inside the measuring column 1 through the installation cavity 12, and flange plates 11 are provided at both axial ends of the measuring column 1. Through the flange plates 11, the downhole pressure monitoring device 100 is connected to the connecting cylinder 200 and the guiding and anchoring device 300. Among them, one end of the connecting cylinder 200 is connected to the downhole pressure monitoring device 100 through the cooperation of the flange plate 11 and bolts, and the other end is connected to the equipment on the ground to realize lowering the measuring column 1 to a specified position downhole. Among them, the guiding and anchoring device 300 is used to realize guiding during the lowering process and fixing the downhole pressure monitoring device 100 when it reaches the specified position. In a specific case, the guiding and anchoring device 300 includes a columnar housing. One end of the columnar housing is connected to the downhole pressure monitoring device 100 through the cooperation of the flange plate 11 and bolts. At least two guiding blocks 301 are symmetrically arranged on the outer wall of the columnar housing. Inside the columnar housing, there are a connecting rod 302, a slider 303, a lead screw 304, and a motor 305; among them, the motor 305 is fixed inside the columnar housing. One end of the lead screw 304 is connected to the power output shaft of the motor 305, and the other end is rotatably connected to the inner wall of the columnar housing. The slider 303 is slidably arranged on the lead screw 304. By the forward and reverse rotation of the motor 305, the slider 303 reciprocates on the lead screw 304. One end of the connecting rod 302 is hinged to the slider 303, and the other end is hinged to the guiding block 301. The guiding block 301 can be moved closer to or away from the columnar housing by the reciprocating movement of the slider 303 on the lead screw 304 to adapt to the turning in the well. When the downhole pressure monitoring device 100 reaches the specified position, the motor 305 is controlled to rotate, so that the guiding block 301 moves away from the columnar housing until the guiding block 301 is clamped on the well wall.

[0059] Enclosure 3, arranged inside the installation cavity 12. One end of the enclosure 3 is an open end, and a pressure sensor 10 for realizing pressure acquisition can be installed inside the enclosure 3 through this open end. A through groove 35 is provided on the side wall of the enclosure 3; the purpose of arranging the enclosure 3 is that it can cooperate with other components to form a closed cavity inside the enclosure 3, isolate the pressure sensor 10 from the downhole environment, and the pressure outside the enclosure 3 is the same as the downhole environment.

[0060] A sealing cylinder 5 is used to seal the open end of the surrounding cylinder 3. The sealing cylinder 5 includes a second cylinder body 51. A flexible diaphragm 52 is arranged inside the second cylinder body 51. The flexible diaphragm 52 is used to seal the channel inside the second cylinder body 51. The flexible diaphragm 52 can not only block the airflow or liquid in the well environment from entering the closed cavity formed inside the surrounding cylinder 3, but also reflect the well pressure. The flexible diaphragm 52 is made of existing materials, which can be an existing pressure sensing membrane, specifically, it can be made of materials such as metal membrane, rubber membrane or polymer membrane, etc. A clamping groove 511 opposite to the through groove 35 is arranged on the outer wall of the second cylinder body 51. During specific use, the outer wall of the second cylinder body 51 is in close contact with the inner wall of the surrounding cylinder 3 to achieve the seal between the outer wall of the second cylinder body 51 and the inner wall of the surrounding cylinder 3. In order to better achieve the seal between the outer wall of the second cylinder body 51 and the inner wall of the surrounding cylinder 3, the second cylinder body 51 can be made of plastic, and the seal of the inner channel of the second cylinder body 51 is achieved through the flexible diaphragm 52, thereby realizing that the sealing cylinder 5 seals the open end of the surrounding cylinder 3, so that the pressure sensor 10 inside the surrounding cylinder 3 is completely placed in a closed cavity.

[0061] In a preferred case, inner guiding strips 33 are arranged on the inner wall of the surrounding cylinder 3, and second sliding grooves cooperating with the inner guiding strips 33 are arranged on the outer wall of the second cylinder body 51. The outer wall of the second cylinder body 51 is in close contact with the inner wall of the surrounding cylinder 3. By using the inner guiding strips 33 to slide in the second sliding grooves, the circumferential displacement of the sealing cylinder 5 can be limited to ensure that the sealing cylinder 5 can only perform vertical displacement, that is, it can ensure that the clamping groove 511 on the outer wall of the second cylinder body 51 is moved to the corresponding position of the through groove 35. Preferably, the second sliding grooves are arranged above the clamping grooves 511, which can not only achieve guiding, but also use the seal 6 to strengthen the seal of the second sliding grooves.

[0062] A pressure sensor 10 is arranged inside the surrounding cylinder 3, and the measuring end of the pressure sensor 10 is in contact with the flexible diaphragm 52. Since the flexible diaphragm 52 is a flexible film, the pressure it receives can reflect the external environmental pressure. In this embodiment, the installation cavity 12 outside the flexible diaphragm 52 is communicated with the downhole environment. Therefore, the pressure received by the flexible diaphragm 52 can reflect the downhole environmental pressure, that is, in this embodiment, the downhole environmental pressure can be directly collected by the pressure sensor 10 placed in the closed cavity. During actual use, because the downhole pressure is relatively large, the pressure generated by the contact between the pressure sensor 10 and the flexible diaphragm 52 can be ignored. The pressure sensor 10 of this embodiment uses a wireless communication module for signal transmission to reduce the use of signal cables.

[0063] In this embodiment, the pressure sensor 10 is fixed in the cylinder 3 through a clamping mechanism 8. The clamping mechanism 8 includes a limiting cylinder 82. The inner diameter of the limiting cylinder 82 is larger than the maximum size of the outer shell of the pressure sensor 10. The limiting cylinder 82 is connected to the inner wall of the cylinder 3 through a fixed cross bar 83. A plurality of adjusting bolts 81 are arranged on the limiting cylinder 82. During use, the end of the pressure sensor 10 away from the flexible diaphragm 52 is inserted into the limiting cylinder 82, and then by tightening the adjusting bolts 81, the clamping and fixing of the pressure sensor 10 by the plurality of adjusting bolts 81 is realized.

[0064] In a preferred case, a positioning groove is arranged on the inner wall of the measuring column 1, and a buffer pad 9 is arranged in the positioning groove. The end of the pressure sensor 10 away from the flexible diaphragm 52 is fixed in the buffer pad 9.

[0065] A sliding seal assembly is used to realize the sealed connection between the sealing cylinder 5 and the cylinder 3. The sliding seal assembly includes a sliding positioning cylinder 4 and a seal 6. The seal 6 is arranged in the through groove 35. The seal 6 can perform radial displacement under the extrusion of the sliding positioning cylinder 4 or the sealing cylinder 5. The sliding positioning cylinder 4 is slidably arranged on the outer wall of the cylinder 3. The inner wall of the sliding positioning cylinder 4 has a convex portion 42. The convex portion 42 is used to squeeze and fix the seal 6 in the clamping groove 511. Specifically, the sliding positioning cylinder 4 includes a first cylinder body 41. The first cylinder body 41 is slidably arranged outside the cylinder 3. The inner diameter of the first cylinder body 41 is larger than the outer diameter of the cylinder 3, that is, there is a certain distance between the inner wall of the first cylinder body 41 and the outer wall of the cylinder 3. A convex portion 42 is arranged on the inner wall of the first cylinder body 41. The thickness of the convex portion 42 is equal to the distance between the inner wall of the first cylinder body 41 and the outer wall of the cylinder 3, that is, the convex portion 42 can realize close contact with the outer wall of the cylinder 3; the specific shape of the convex portion 42 can be an annular convexity or a plurality of convexities arranged circumferentially. The convexities correspond to the through grooves 35 one by one. In this embodiment, the convex portion 42 can be used to squeeze the seal 6 to realize the radial inward movement of the seal 6 and snap it into the clamping groove 511. In a preferred case, in order to facilitate the up and down displacement of the sliding positioning cylinder 4, outer guiding strips 32 are arranged on the outer wall of the cylinder 3; a first sliding groove matching with the outer guiding strips 32 is arranged on the inner wall of the sliding positioning cylinder 4. The outer guiding strips 32 and the first sliding groove cooperate to limit the circumferential displacement of the sliding positioning cylinder 4, ensuring that the sliding positioning cylinder 4 can only perform vertical displacement. Furthermore, it can ensure that during the up and down displacement of the sliding positioning cylinder 4, the convex portion 42 can act on the seal 6. The specific sealing form of the seal 6 can adopt hard sealing or soft sealing. Among them, in the case of hard sealing, the seal 6 is made of a hard material and realizes sealing directly through the shape of the seal 6 in close contact with the clamping groove 511; in the case of soft sealing, the seal 6 is made of plastic and can use the plasticity of the plastic for sealing.

[0066] In this embodiment, considering that the usage environment of the downhole pressure monitoring device 100 is downhole, and the downhole environment has a relatively large pressure. If the sealing connection between the sealing cylinder 5 and the surrounding cylinder 3 is achieved only by the close contact between them, when there is a relatively large pressure downhole, there will be a relatively large pressure difference between the inner and outer sides of the surrounding cylinder 3. At this time, a downward pressure will be applied to the sealing cylinder 5, which will reduce the stability of the sealing connection between the sealing cylinder 5 and the surrounding cylinder 3. When the sealing cylinder 5 becomes unstable and moves downward, it may cause the flexible diaphragm 52 to be punctured by the pressure sensor 10 or cause damage to the pressure sensor 10. The downward direction in this embodiment refers to the position and direction shown by Figure 1 and can actually be understood as the axial inward direction of the surrounding cylinder 3.

[0067] In order to improve the stability of the sealing connection between the sealing cylinder 5 and the surrounding cylinder 3 in this embodiment, a sliding seal assembly is designed. This sliding seal assembly can not only improve the sealing performance between the sealing cylinder 5 and the surrounding cylinder 3, but also improve the stability of the sealing connection between the sealing cylinder 5 and the surrounding cylinder 3. In this embodiment, a through groove 35 is provided on the side wall of the surrounding cylinder 3. The through groove 35 is used to place the seal 6, and the seal 6 can perform radial displacement under the extrusion of the sealing cylinder 5 or the sliding positioning cylinder 4. When the seal 6 moves into the card slot 511, the seal 6 can not only achieve sealing, but also has a blocking effect on the downward displacement of the sealing cylinder 5, which can improve the compressive effect of the sealing cylinder 5, and thus improve the stability of its sealing connection with the surrounding cylinder 3.

[0068] Among them, the specific shapes of the seal 6 and the through groove 35 are not limited, as long as it can meet the requirement that the seal 6 can perform radial displacement in the through groove 35 under the extrusion of the sealing cylinder 5 or the sliding positioning cylinder 4, and after the seal 6 is extruded into the card slot 511, the seal 6 can block the through groove 35. Preferably, the shape of the card slot 511 matches the shape of the end of the seal 6 inserted into the card slot 511, so that after the seal 6 is extruded into the card slot 511, the card slot 511 is filled, further meeting the requirements of improving the stability of the sealing cylinder 5 and the sealing performance between the sealing cylinder 5 and the surrounding cylinder 3. In this embodiment, 6 through grooves 35 are provided on the side wall of the surrounding cylinder 3 in the same circumferential direction. The axial width of the through groove 35 gradually increases from the inside to the outside, and the innermost end of the through groove 35 is a circular hole, that is, the end of the through groove 35 close to the inside of the surrounding cylinder 3 has the smallest size. More specifically, both the innermost end and the outermost end of the through groove 35 are circular holes. The innermost end refers to the end close to the inside of the surrounding cylinder 3. The axial sectional curve of the inner wall of the through groove 35, the seal 6 is a sealing sphere, and the diameter of the sealing sphere is greater than the width of the surrounding cylinder 3, that is, the diameter of the sealing sphere is greater than the radial width of the through groove 35, and the diameter of the sealing sphere is greater than or equal to the axial width of the innermost end of the through groove 35; as Figure 1 shown, the radial width of the through groove 35 refers to Figure 1 the horizontal direction in Figure 1in the vertical direction.

[0069] In a preferred case, a limiting plate 31 is provided below the through groove 35 on the outer wall of the surrounding cylinder 3; the sliding seal assembly further includes a first spring 7, and the first spring 7 is arranged between the limiting plate 31 and the protruding part 42. In this embodiment, the first spring 7 is wound around the outside of the surrounding cylinder 3. In the above manner, only one first spring 7 can be directly provided, and the following settings can also be made: a plurality of independent first springs 7 are arranged between the limiting plate 31 and the protruding part 42, and the first springs 7 are arranged in the space surrounded by the surrounding cylinder 3, the protruding part 42, the limiting plate 31 and the first cylinder body 41.

[0070] The working process of the sliding seal assembly in this embodiment is as follows:

[0071] As Figure 3 shown, an axial thrust is applied to the sliding positioning cylinder 4 through an operating rod. The specific operation is to directly abut or clamp the end of an operating rod against the top of the first cylinder body 41 to apply an axial thrust, so that the sliding positioning cylinder 4 moves downward, and the protruding part 42 moves below the through groove 35. At this time, although there is a certain distance between the first cylinder body 41 above the protruding part 42 and the surrounding cylinder 3, it can still block the seal 6 to prevent the seal 6 from moving out of the through groove 35 under the extrusion of the sealing cylinder 5. And at this time, the first spring 7 is compressed between the limiting plate 31 and the protruding part 42; then the sealing cylinder 5 is inserted into the open end of the surrounding cylinder 3, and the second cylinder body 51 is in close contact with the surrounding cylinder 3. Under the extrusion of the second cylinder body 51, the seal 6 moves radially outward and is blocked by the first cylinder body 41 above the protruding part 42. When the card slot 511 moves to the position opposite to the through groove 35, the sealing cylinder 5 is no longer moved. At this time, the measuring end of the pressure sensor 10 abuts against the flexible diaphragm 52; then the operating rod is removed, and the sliding positioning cylinder 4 moves upward under the restoring force of the first spring 7 until the protruding part 42 squeezes the seal 6 into the card slot 511. At this time, as Figure 1 shown, the protruding part 42 closes the outermost end of the through groove, the seal 6 is clamped at the innermost end of the through groove 35 by the protruding part 42, and a part of the seal 6 is placed in the card slot 511 to support the sealing cylinder 5 and improve its stability.

[0072] In a preferred case, the installation cavity 12 has an open end, and the downhole pressure monitoring device further includes:

[0073] A sealing cover 2 for closing the open end of the installation cavity 12. Among them, the sealing cover 2 is connected to the side wall of the measuring column 1 by bolts, and a through hole 21 communicating with the installation cavity 12 is provided on the sealing cover 2; preferably, a filter element is provided in the through hole 21, and the filter element can prevent mud and sand in the well from entering the installation cavity 12.

[0074] In a preferred case, the open end of the surrounding cylinder 3 is arranged opposite to the sealing cover 2, specifically as shown in Figure 1 As shown, a sealing cover 2 is provided on the side wall of the measuring column 1. The open end of the surrounding cylinder 3 and the sealing cover 2 are located on the same side of the axis of the measuring column 1, and there is a distance between the end of the open end of the surrounding cylinder 3 and the sealing cover 2. An annular baffle 34 is provided at the end of the open end of the surrounding cylinder 3. The thickness of the annular baffle 34 is smaller than that of the surrounding cylinder 3. An equal-pressure chamber 13 is formed inside the annular baffle 34. The equal-pressure chamber 13 is communicated with the underground environment through a through hole 21. The effect of the above setting is that after the open end of the installation cavity 12 is closed by the sealing cover 2, only the equal-pressure chamber 13 inside the annular baffle 34 is communicated with the underground environment, which will not only not affect the pressure acquisition of the underground by the pressure sensor 10, but also be beneficial to protecting components such as the sliding positioning cylinder 4 and the sealing member 6. To achieve the above effect, the end of the open end of the surrounding cylinder 3 can also be abutted against the sealing cover 2. Preferably, an annular baffle 34 with a thickness smaller than that of the surrounding cylinder 3 is provided, which can reduce the friction between the sealing cylinder 5 and the surrounding cylinder 3 during the installation process.

[0075] The usage method of the underground pressure monitoring device based on wireless data transmission in this embodiment includes the following steps:

[0076] S1. Remove the sealing cover 2 and the sealing cylinder 5, fix the pressure sensor 10 inside the surrounding cylinder 3, and make the measuring end of the pressure sensor 10 located at the open end of the surrounding cylinder 3;

[0077] S2. Apply an axial thrust to the sliding positioning cylinder 4 through an operating rod, so that the sliding positioning cylinder 4 moves downward, the protruding portion 42 moves below the through groove 35, and the first spring 7 is compressed;

[0078] S3. Insert the sealing cylinder 5 into the open end of the surrounding cylinder 3. Under the extrusion of the second cylinder body 51, the sealing member 6 moves radially outward. When the card slot 511 moves to a position opposite to the through groove 35, stop moving the sealing cylinder 5. At this time, the measuring end of the pressure sensor 10 is in contact with the flexible diaphragm 52;

[0079] S4. Under the restoring force of the first spring 7, the sliding positioning cylinder 4 moves upward until the protruding portion 42 moves to a position opposite to the through groove 35. At this time, under the extrusion of the protruding portion 42, the sealing member 6 moves radially inward and enters the card slot 511; Install the sealing cover 2;

[0080] S5. After connecting the underground pressure monitoring device 100 with the connecting cylinder body 200 and the guiding and anchoring device 300, move the underground pressure monitoring device 100 to a designated position underground through a ground hoisting device; The underground pressure monitoring device 100 in this embodiment is provided with a displacement sensor.

[0081] In this embodiment, a closed cavity for installing the pressure sensor 10 is arranged inside the measuring column 1, and the closed cavity is sealed by a sealing cylinder 5 provided with a flexible diaphragm 52. At the same time, the outer space of the flexible diaphragm 52 communicates with the downhole space, so that the pressure received by the flexible diaphragm 52 can reflect the downhole pressure. By abutting the measuring end of the pressure sensor 10 against the flexible diaphragm 52, the pressure sensor 10 directly uses the pressure received by the flexible diaphragm 52 to reflect the downhole pressure, avoiding the problem of low service life caused by the high temperature and corrosion of the downhole environment when the pressure sensor is directly exposed to the downhole environment to measure the downhole pressure. Moreover, the way of arranging the sliding seal assembly in cooperation with the sealing cylinder 5 in this embodiment can not only arrange the pressure sensor 10 in a closed cavity, but also ensure that the sealing cylinder 5 still has good stability under the well pressure.

[0082] The downhole pressure monitoring device based on wireless data transmission in this embodiment can be used for downhole pressure monitoring during oil or natural gas exploitation.

[0083] Embodiment 2:

[0084] As Figures 7 - 8 shown, this embodiment is based on Embodiment 1, and the difference from Embodiment 1 is that the shape of the through groove 35 is different. In this embodiment, both the innermost end and the outermost end of the through groove 35 are circular holes, and the axial section of the inner wall of the through groove 35 is a straight line. That is, in this embodiment, the through groove 35 is a regular frustum-shaped hole, and the minimum inner diameter of the frustum-shaped hole is smaller than the diameter of the sealing sphere.

[0085] Embodiment 3:

[0086] As Figure 9 shown, this embodiment is based on Embodiment 1, and the difference from Embodiment 1 is that the shape of the seal 6 is different. In this embodiment, the seal 6 is a sealed ellipsoid, and the major axis of the sealed ellipsoid is greater than the width of the surrounding cylinder 3, that is, the length of the major axis of the sealed ellipsoid is greater than the radial width of the through groove 35, and the length of the minor axis of the sealed ellipsoid is greater than or equal to the axial width of the through groove 35.

[0087] Embodiment 4:

[0088] As Figure 10 shown, this embodiment is based on Embodiment 1, and the difference from Embodiment 1 is that the shapes of the through groove 35 and the seal 6 are different. In this embodiment, the through groove 35 is an equi-width strip-shaped groove, and the seal 6 is a strip-shaped seal body that is slidably and sealedly connected to the through groove 35. The length of the strip-shaped seal body is greater than the width of the surrounding cylinder 3, and both ends of the strip-shaped seal body are arc surfaces.

[0089] The above specific embodiments have further elaborated on the purpose, technical solution and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0090] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the conditions under which the present invention can be implemented. Therefore, they do not have a substantial technical meaning. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of clear description and are not used to limit the scope within which the present invention can be implemented. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope within which the present invention can be implemented.

Claims

1. An underground pressure monitoring device based on wireless data transmission, characterized in that, Comprising: A measuring column (1) with an installation cavity (12) communicated with the downhole environment provided therein; A surrounding cylinder (3) disposed in the installation cavity (12), one end of the surrounding cylinder (3) being an open end, and a through groove (35) being provided on the side wall of the surrounding cylinder (3); A sealing cylinder (5) for closing the open end of the surrounding cylinder (3), the sealing cylinder (5) including a second cylinder body (51), a flexible diaphragm (52) being provided in the second cylinder body (51), and a clamping groove (511) opposite to the through groove (35) being provided on the outer wall of the second cylinder body (51); A pressure sensor (10) disposed in the surrounding cylinder (3), the measuring end of the pressure sensor (10) being in contact with the flexible diaphragm (52); A sliding seal assembly for realizing the sealed connection between the sealing cylinder (5) and the surrounding cylinder (3), the sliding seal assembly including a sliding positioning cylinder (4) and a seal (6), the seal (6) being disposed in the through groove (35), the seal (6) being capable of radially displacing under the extrusion of the sliding positioning cylinder (4) or the sealing cylinder (5), the sliding positioning cylinder (4) being slidably disposed on the outer wall of the surrounding cylinder (3), and a protruding portion (42) being provided on the inner wall of the sliding positioning cylinder (4), the protruding portion (42) being used for squeezing and fixing the seal (6) in the clamping groove (511); The installation cavity (12) has an open end, and the downhole pressure monitoring device further includes: A sealing cover (2) for closing the open end of the installation cavity (12), a through hole (21) communicated with the installation cavity (12) being provided on the sealing cover (2); A filter element being provided in the through hole (21); An outer guiding strip (32) being provided on the outer wall of the surrounding cylinder (3); a first sliding groove cooperating with the outer guiding strip (32) being provided on the inner wall of the sliding positioning cylinder (4).

2. The downhole pressure monitoring device based on wireless data transmission according to claim 1, characterized in that The open end of the surrounding cylinder (3) is disposed opposite to the sealing cover (2), and there is a spacing between the end portion of the open end of the surrounding cylinder (3) and the sealing cover (2). An annular baffle (34) is provided at the end portion of the open end of the surrounding cylinder (3), and an equal-pressure cavity (13) is formed inside the annular baffle (34), and the equal-pressure cavity (13) is communicated with the downhole environment through the through hole (21); or the end portion of the open end of the surrounding cylinder (3) abuts against the sealing cover (2).

3. The downhole pressure monitoring device based on wireless data transmission according to claim 1, characterized in that A limiting plate (31) is provided on the outer wall of the surrounding cylinder (3) below the through groove (35); the sliding seal assembly further includes a first spring (7), and the first spring (7) is disposed between the limiting plate (31) and the protruding portion (42).

4. The downhole pressure monitoring device based on wireless data transmission according to claim 1, characterized in that, The axial width of the through groove (35) gradually increases from inside to outside, and the innermost end of the through groove (35) is a circular hole; the seal (6) is a sealed sphere or a sealed ellipsoid, the diameter of the sealed sphere being greater than the width of the surrounding cylinder (3); the major axis of the sealed ellipsoid being greater than the width of the surrounding cylinder (3).

5. The downhole pressure monitoring device based on wireless data transmission according to claim 1, characterized in that, Both the innermost end and the outermost end of the through groove (35) are circular holes.

6. The downhole pressure monitoring device based on wireless data transmission according to claim 1, wherein The through groove (35) is a strip-shaped groove with a constant width, the seal (6) is a strip-shaped sealing body that is slidably and sealingly connected to the through groove (35), the length of the strip-shaped sealing body is greater than the width of the surrounding cylinder (3), and both ends of the strip-shaped sealing body are arc surfaces.

7. The downhole pressure monitoring device based on wireless data transmission according to claim 1, characterized in that Inner guiding strips (33) are provided on the inner wall of the surrounding cylinder (3), and second sliding grooves that cooperate with the inner guiding strips (33) are provided on the outer wall of the second cylinder body (51); the outer wall of the second cylinder body (51) is in close contact with the inner wall of the surrounding cylinder (3).

8. The downhole pressure monitoring device based on wireless data transmission according to claim 7, characterized in that, The second sliding groove is provided above the clamping groove (511).

9. The method of using the downhole pressure monitoring device based on wireless data transmission according to any one of claims 1-8, characterized in that, It includes the following steps: S1. Fix the pressure sensor (10) inside the surrounding cylinder (3) so that the measuring end of the pressure sensor (10) is located at the open end of the surrounding cylinder (3); S2. Apply an axial thrust to the sliding positioning cylinder (4) through an operating rod to move the sliding positioning cylinder (4) downward so that the protruding portion (42) moves below the through groove (35); S3. Insert the sealing cylinder (5) into the open end of the surrounding cylinder (3). Under the extrusion of the second cylinder body (51), the seal (6) moves radially outward. When the clamping groove (511) moves to a position opposite to the through groove (35), stop moving the sealing cylinder (5). At this time, the measuring end of the pressure sensor (10) abuts against the flexible diaphragm (52); S4. Apply an axial pulling force to the sliding positioning cylinder (4) through the operating rod to move the sliding positioning cylinder (4) upward until the protruding portion (42) moves to a position opposite to the through groove (35). At this time, under the extrusion of the protruding portion (42), the seal (6) moves radially inward into the clamping groove (511).

10. Application of the downhole pressure monitoring device based on wireless data transmission according to any one of claims 1-8, characterized in that, It is used for downhole pressure monitoring during oil or natural gas extraction.

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