Compressed air energy storage horizontal well high-frequency injection and production pipe column and completion method

Abstract

The application is a compressed air energy storage horizontal well high-frequency injection and production pipe column and completion method, the injection and production pipe column is connected with downhole combined sealing device, downhole annular flow limiting device and downhole safety valve from bottom to top through tubing, the downhole combined sealing device is inserted and connected by prepositioning working barrel and sealing working barrel, the sealing insert barrel seals the sealing insert barrel sealing cavity of prepositioning lower outer barrel, the sealing assembly seals the sealing part sealing cavity of prepositioning lower outer barrel, the downhole annular flow limiting device is provided with a skin bowl and a center tube, the flow limiting plate of the staggered collection flow channel is fixed in the flow limiting plate mounting groove in the wall of the center tube, and the seat sealing hole and the seat sealing boost hole are arranged in the wall without the flow limiting plate mounting groove. The injection and production pipe column provided by the application has the reverse well washing function, the scaling and waxing in the tubing are cleaned through the reverse circulation of the well washing fluid with the cleaning function, the maintenance is realized without moving the pipe column, the conventional operation cost and time are reduced, and the working efficiency of the gas storage is improved.

Description

TECHNICAL FIELD

[0001] The application relates to the field of gas storage construction in oil field development of the petroleum industry and the field of carbon dioxide injection technology, and particularly relates to a compressed air energy storage horizontal well high-frequency injection and production pipe column and a well completion method. BACKGROUND

[0002] An underground gas storage has advantages such as safety and large storage capacity, and in particular, the construction of a compressed air energy storage type gas storage, because the stored energy is electric energy, compressed air is only a medium in energy conversion, and when the air is applied, the air needs to be converted into electric energy again through a turbine, so that the displacement, anchoring, sealing, corrosion resistance and anti-fouling of the injection and production pipe column are more demanding.

[0003] The injection and production pipe column in the existing natural gas storage has a long injection and production cycle and low frequency, and the air-tight packer used in the pipe column can meet the injection and production requirements, for example, the patent technologies disclosed in the authorized announcement CN112647857B and the authorized announcement CN206205797U, both of which use a packer for anchoring and sealing.

[0004] However, if the above technologies are applied to the injection and production pipe column of the compressed air storage, the packer cannot meet the injection and production requirements. The working state of the injection and production pipe column of the compressed air storage under harsh working conditions is fully analyzed and described in the articles such as "Dynamic characteristics of flow-induced vibration and buckling of gas storage injection and production pipe column" and "Buckling behavior of gas storage tubing under multi-cycle injection and production conditions".

[0005] The site selection of a domestic storage area is mostly a depleted oil and gas reservoir area, and compared with a salt cavern type gas storage or a cavity type gas storage, the characteristics of the gas storage layer for storing gas are small storage capacity, thin reservoir, large interlayer difference, serious sand production and strong geological heterogeneity, and the edge and bottom water is active.

[0006] In order to meet the conditions such as storage capacity, injection and production displacement and pressure of the depleted oil and gas reservoir area, the well type of the injection and production well is suitable to be a horizontal well structure, but most of the built compressed air storage selects a salt cavern type and adopts a straight and inclined well structure. Therefore, a new type of injection and production pipe column and a matching process are urgently needed to solve the above problems. SUMMARY

[0007] To solve the above problems, the application provides a compressed air energy storage horizontal well high-frequency injection and production pipe column and a completion method, mainly to solve the problem that the injection and production pipe columns used in the existing salt cavern type and depleted gas storage cannot meet the injection and production pipe column use requirements in the compressed air energy storage established by the depleted reservoir, and to provide an injection and production pipe column suitable for the high-frequency injection and production of the compressed air energy storage horizontal well. The production efficiency of the compressed air energy storage is improved, and the injection and production benefits are improved.

[0008] The technical solution of the application is: a compressed air energy storage horizontal well high-frequency injection and production pipe column, which is provided with a tubing and a downhole safety valve, wherein: the injection and production pipe column is sequentially connected with a downhole combined sealing device, a downhole annular flow limiting device and the downhole safety valve through the tubing from bottom to top, the downhole combined sealing device is inserted and connected by a preset working barrel and a sealing working barrel; in the preset working barrel, a preset locking ring provided with a dog tooth is installed between a preset upper outer barrel and a preset lower outer barrel, the preset upper outer barrel is connected with the preset lower outer barrel, and the preset working barrel is advanced and lowered into a preset horizontal section in the well with the completion pipe column; the sealing working barrel comprises a sealing part mainly composed of a sealing insert barrel and a sealing assembly, and an inner barrel; the inner barrel is provided with a backwashing hole and a backwashing control hole, and the outer circle of a limiting step three in the inner barrel is processed with a dog tooth; the sealing working barrel is connected at the lower end of the injection and production pipe column and lowered into the preset working barrel, the inner barrel is connected with the dog tooth in the preset locking ring, the sealing insert barrel seals a sealing insert barrel sealing cavity of the preset lower outer barrel, and the sealing assembly seals a sealing part sealing cavity of the preset lower outer barrel; the downhole annular flow limiting device is provided with a skin bowl and a central tube, a flow limiting plate of a staggered collection flow channel is fixed in a flow limiting plate mounting groove in the wall of the central tube, and a seat sealing hole and a seat sealing boosting hole are arranged in the wall without the flow limiting plate mounting groove; above a pushing barrel limiting step of the central tube, a flow limiting device sliding barrel, the skin bowl and an upper pushing barrel are sequentially installed from top to bottom; the flow limiting device limiting ring installed with a locking ring is arranged in the flow limiting device sliding barrel above the skin bowl, and the locking ring is installed in a locking ring groove in the outer circle of the central tube; the upper pushing barrel is matched with the flow limiting device locking ring in the locking ring mounting groove of the central tube through the dog tooth.

[0009] Preferably, the sealing working barrel is further provided with an upper locking ring, a working barrel sliding barrel, a working barrel spring, a disc spring, a middle locking ring and a sealing compression ring, the upper locking ring, the working barrel sliding barrel and the working barrel spring are sequentially installed above the limiting step three from top to bottom; the disc spring, the sealing insert barrel, the middle locking ring, the sealing assembly, the sealing compression ring are sequentially installed below the limiting step three from top to bottom.

[0010] Preferably, the top of the ring body of the preset locking ring is provided with a locking ring torque transmission spline, the lower inner circle of the preset locking ring is provided with a dog tooth, and the preset locking ring is an open ring with a straight or inclined through slot opened axially; the preset upper outer cylinder is a non-equal-diameter cylindrical body, the upper inner cavity of the preset upper outer cylinder is provided with an internal thread for connecting with the well completion string, the lower part is a threaded inner cavity, and the middle inner cavity is provided with a locking ring limiting step and an upper outer cylinder torque transmission spline on the inner circle of the locking ring limiting step; the upper outer cylinder torque transmission spline can cooperate with the locking ring torque transmission spline on the top of the ring body of the preset locking ring, and the preset locking ring after cooperation is located in the locking ring installation cavity between the locking ring limiting step and the threaded inner cavity of the lower part.

[0011] Preferably, the preset lower outer cylinder is a non-equal-diameter cylindrical body, the outer circles of the two ends of the preset lower outer cylinder are provided with external threads and can be connected with the internal threads in the threaded inner cavities of the lower part of the preset upper outer cylinder and the lower casing thread in the well completion string respectively; the upper inner cavity of the preset lower outer cylinder is a sealing plug sealing cavity, and the lower inner cavity is a sealing element sealing cavity; the sealing plug sealing cavity is a conical cavity.

[0012] Preferably, the sealing plug can be made of rubber or high polymer material, soft metal or memory alloy material, the lower outer circle of the sealing plug is a conical outer circle which cooperates with the sealing plug sealing cavity of the preset lower outer cylinder; a disc spring top ring is further arranged between the disc spring and the sealing plug.

[0013] Preferably, the inner cylinder is a non-equal-diameter cylindrical body, the injection and production string connecting thread and the spare part connecting thread are arranged at the upper and lower ends of the inner cylinder respectively; the outer circle of the inner cylinder is sequentially provided with limiting step one, limiting step two, limiting step three, limiting step four and limiting step five from top to bottom, and the outer circles of the limiting step one, limiting step two, limiting step three, limiting step four and limiting step five are all precisely processed outer circle surfaces.

[0014] Preferably, the backwashing hole and the backwashing control hole are arranged in the limiting step one, the backwashing hole is arranged in the outer circle below the injection and production string connecting thread and is provided with sealing ring groove one and a sealing ring on the upper and lower sides of the backwashing hole; the backwashing control hole is arranged at the root of the limiting step one and at least one sealing ring groove two is arranged on the top outer circle of the limiting step two; the limiting step three has the largest outer diameter and is provided with a dog tooth on the outer circle, the middle locking ring connecting thread is arranged at the lower end of the outer circle of the limiting step four; the spare part connecting thread is arranged at the lower part of the limiting step five.

[0015] Preferably, the center locking ring is provided with a center hole and the inner circle is provided with a thread, and the inner thread of the inner circle is threadedly connected with the center locking ring after the center locking ring is sleeved on the outside of the inner cylinder; the sealing assembly is a combined seal, which at least includes a sealing ring and a polytetrafluoroethylene-made protective ring respectively installed on both sides of the sealing ring, and the outer diameter of the sealing ring is greater than the inner diameter of the sealing cavity of the preset lower outer cylinder; the sealing compression ring is threadedly connected with the spare part of the lower part of the limiting step, and the lower compression ring and the dissolvable plug are further connected below the sealing compression ring.

[0016] Preferably, the inner circle of the working cylinder sliding cylinder is processed into two sections of inner diameters with the small section being installed on the outside of the limiting step one of the inner cylinder and the large section being installed on the outside of the limiting step two, and the two sections of inner diameters of the inner circle of the working cylinder sliding cylinder are both finished surfaces; in the normal working state, the small section of the inner diameter of the working cylinder sliding cylinder blocks the backwashing hole, and the large section of the inner diameter is in communication with the backwashing control hole.

[0017] Preferably, the skin bowl is installed in the flow limiting device sliding cylinder and the lower part is located between the flow limiting device sliding cylinder and the upper pushing cylinder, and the sealing surface of the outer circle of the center pipe is provided with a sealing element; the staggered collection flow channel is composed of a main channel groove processed in the center of the flow limiting plate and auxiliary channel grooves in communication with the main channel groove; the limiting plate installation groove provided on the outer wall of the center pipe and the flow limiting plate are provided in more than one set, and the flow limiting plate is welded in the limiting plate installation groove.

[0018] Preferably, the main channel groove is a straight groove passing through both ends of the flow limiting plate body; the auxiliary channel grooves are arranged on both sides of the main channel groove and have arc-shaped and downward inclined shapes, and the auxiliary channel grooves on both sides are staggered and connected head to tail in the main channel groove.

[0019] Preferably, the locking ring and the flow limiting device locking ring are both broken rings provided with axial notches, the axial notches are oblique notches with an oblique angle of 1-89 degrees or vertical notches; the inner diameter of the locking ring in the natural state is smaller than the outer diameter of the center pipe section; the outer circle of the flow limiting device locking ring is processed into a zigzag shape and can be matched with the zigzag-shaped inner circle of the upper pushing cylinder.

[0020] Preferably, the upper pushing cylinder is a non-equal-diameter cylindrical body provided with an upper cylinder body and a retreat-stopping thread provided in a lower cylinder body, the inner diameter of the upper cylinder body is smaller than that of the lower cylinder body, at least one auxiliary sealing liquid passing groove is provided on the outer wall of the upper cylinder body, and the auxiliary sealing liquid passing groove is in communication with the top of the upper cylinder body; the inner circle of the lower cylinder body of the upper pushing cylinder is provided with a retreat-stopping thread, and the retreat-stopping thread is a zigzag-shaped thread and can be matched with the zigzag-shaped thread of the outer circle of the flow limiting device locking ring.

[0021] Preferably, the outer circle of the center pipe below the limiting step of the upper pushing cylinder is processed into a continuation thread, and the continuation thread can be threadedly connected with the auxiliary sealing liquid passing groove.

[0022] Preferably, the said auxiliary washing anti-spray mechanism is provided with a flow limiting device upper outer cylinder, a flow limiting device lower outer cylinder, a lower pushing cylinder, a flow limiting device spring and a limiting cylinder, the two ends of the flow limiting device upper outer cylinder are respectively connected with the continuation thread in the central pipe and the flow limiting device lower outer cylinder, the said lower pushing cylinder and flow limiting device spring are installed in the flow limiting device lower outer cylinder, the said limiting cylinder is installed below the flow limiting device spring and is threadedly connected with the flow limiting device lower outer cylinder, and at least one auxiliary washing anti-spray liquid passage is provided in the limiting cylinder.

[0023] Preferably, the inner circle of the flow limiting device lower outer cylinder is a non-equal-diameter inner circle, and the internal threads at the two ends are respectively threadedly connected with the flow limiting device upper outer cylinder and the limiting cylinder; an inner taper matching surface is arranged between the two non-equal-diameter inner circles of the flow limiting device lower outer cylinder, and the inner taper matching surface is a lower inclined surface.

[0024] Preferably, the said lower pushing cylinder is a non-equal-diameter cylindrical body, the upper outer wall of the lower pushing cylinder is an outer taper matching surface, the outer taper matching surface is an upper inclined surface and can be matched with the inner taper matching surface in the flow limiting device lower outer cylinder, and at least one sealing ring groove is processed in the outer taper matching surface; the flow limiting device spring is installed in the inner cavity below the spring limiting step in the lower pushing cylinder.

[0025] Preferably, the upper outer circle of the limiting cylinder is provided with an external thread and can be threadedly connected with the flow limiting device lower outer cylinder; the auxiliary washing anti-spray liquid passage arranged in the outer wall of the limiting cylinder is a through slot from top to bottom and at least one is provided; the flow limiting device upper outer cylinder is a non-equal-diameter cylindrical body, and the internal and external threads in the cylinder bodies at the upper and lower ends can be respectively connected with the continuation thread of the central pipe and the flow limiting device lower outer cylinder, and the lower inner cavity of the flow limiting device upper outer cylinder after being connected with the central pipe is in communication with the limiting plate installation groove.

[0026] Preferably, a centralizer is connected in the high-frequency injection and production pipe column in the straight well section on the upper and lower sides of the said downhole annulus flow limiting device, and a flow joint is connected in the high-frequency injection and production pipe column in the straight well section on the upper and lower sides of the said downhole safety valve; the oil pipe includes a small-diameter oil pipe, a large-diameter oil pipe and a small-diameter thickened oil pipe, the centralizer and the downhole annulus flow limiting device are connected in series in the small-diameter oil pipe, the downhole safety valve and the flow joint are connected in series in the large-diameter oil pipe, and the small-diameter thickened oil pipe and the downhole gas-solid separator are connected in series between the small-diameter oil pipe and the sealing working cylinder.

[0027] Preferably, the said downhole gas-solid separator is provided with a separator upper connector, an outer shell, a sand filtering cylinder, a cyclone vane and a separator lower connector, the sand filtering cylinder with a centralizer and the cyclone vane are respectively installed in the upper and lower parts of the outer shell, a sealing ring is installed between the upper end of the outer shell and the sand filtering cylinder and is threadedly connected with the separator upper connector; a sealing ring is installed between the lower part of the outer shell and the separator lower connector and is threadedly connected with the separator lower connector, and the cyclone vane is blocked in the outer shell.

[0028] Preferably, the upper inner cavity of the outer shell is larger than the lower inner cavity, and a tapered transition cavity is arranged in the middle of the inner cavity; a hole or a groove is arranged in the barrel of the sand filter; the centralizer is arranged at the lower end of the barrel of the sand filter, and the outer diameter of the centralizer is equal to or greater than the maximum inner diameter of the tapered transition cavity of the outer shell; the rotational flow piece is a twisted plate structure, and the equivalent circle outer diameter, the twisted pitch and the thickness of the plate after twisting are matched with the spiral groove processed in the lower inner cavity of the outer shell.

[0029] The well completion method applied to the high-frequency injection-production pipe string of the compressed air energy storage horizontal well comprises the following steps: A, a preset working barrel in a downhole combined sealing device is connected in series in a predetermined position of a well completion pipe string, and the well completion pipe string is lowered into a well for well completion; B, the sealing working barrel is connected to the lower end of the injection-production pipe string and is lowered into the well, the sealing working barrel is pressed down through the injection-production pipe string, and anchoring and sealing of the injection-production pipe string and the well completion pipe string are realized; C, a forward pressure test is performed on the downhole annulus flow limiting device, and whether the injection-production pipe string leaks is tested; D, if the injection-production pipe string does not leak in the pressure test, the downhole annulus flow limiting device is started; E, after the downhole annulus flow limiting device is started, reverse well flushing is continued, and whether the downhole combined sealing device works normally is verified; F, after the downhole combined sealing device is verified to work normally, casing protection fluid is injected; G, the well flushing pipeline is switched to a forward well flushing process, the ground is pressurized after a period of time, the soluble plug in the downhole combined sealing device is broken, and the well completion of the high-frequency injection-production pipe string of the horizontal well is realized.

[0030] Compared with the prior art, the injection-production pipe string has the following advantages: (1) the injection-production pipe string provided by the application adopts a downhole combined sealing device, the preset working barrel in the downhole combined sealing device is lowered into a preset horizontal section of the well together with the well completion pipe string in advance, efficient anchoring of the injection-production pipe string is realized, and the problem that the slips in the packer are prone to loosening and failure under the condition of high-frequency injection-production stress alternation is solved. Meanwhile, the injection-production pipe string provided by the application can also be used in a well for injecting carbon dioxide.

[0031] (2) The injection-production pipe string provided by the application has a reverse well flushing function, can clean the scale and wax in the oil pipe by reverse circulation of the well flushing fluid after a normal injection-production cycle ends, realizes maintenance without moving the pipe string, reduces the conventional operation cost and time, prolongs the service life of the injection-production pipe string, and improves the working efficiency of the gas storage.

[0032] (3) The inner barrel of the sealing working barrel in the application has a reverse well flushing function, is more likely to perform well killing by reverse circulation when blowout occurs, effectively reduces the difficulty of well killing when blowout occurs, and improves the safety factor of the injection-production well from the process principle.

[0033] (4) the downhole combined sealing device in the application compared with the packer used in the existing pipe string, its working principle is simple and reliable, improves the anchoring sealing capacity, enhances the safety of the whole pipe string and tool, the provided backwashing process channel greatly reduces the downhole accident probability caused by the scale blockage or wax blockage in the pipe string after the injection-production well is put into production.

[0034] (5) the injection-production pipe string provided in the application realizes the requirement of the oil sleeve annulus blowout prevention under the premise of ensuring the backwashing channel of the injection-production pipe string, improves the safety of the whole injection-production pipe string.

[0035] (6) the application makes the unlimited injection and replacement of the casing protection fluid possible through the backwashing process channel, can well prevent the corrosion in the oil sleeve annulus of the well, reduces the requirement for the well completion casing material, greatly saves the well completion cost.

[0036] (7) the well completion method provided in the application can check the reliability of the injection-production pipe string in each step in the well completion process, eliminates the injection-production pipe string with hidden dangers into the well.

[0037] In summary, the application improves the safety of the whole pipe string, provides the backwashing process channel, greatly reduces the downhole accident probability caused by the scale blockage in the oil pipe and the requirement for the casing material, prolongs the service life of the injection-production pipe string, improves the working efficiency of the gas storage, has good economic benefit and social benefit, and has great popularization space. BRIEF DESCRIPTION OF DRAWINGS

[0038] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, illustrate the application together with the embodiments of the application, and do not constitute a limitation on the application. In the drawings: Figure 1 is the overall structure schematic diagram of the injection-production pipe string in the application.

[0039] Figure 2 is the structure schematic diagram of the preset working barrel in the application.

[0040] Figure 3 is the structure schematic diagram of the upper outer barrel in the application. Figure 2

[0041] Figure 4 is the structure schematic diagram of the locking ring in the application. Figure 2

[0042] Figure 5 is the structure schematic diagram of the sealing working barrel in the application.

[0043] Figure 6 is the structure schematic diagram of the inner barrel in the application. Figure 5 ​​​

[0044] Figure 7 For Figure 1 Structure diagram of the middle annular space flow limiting device.

[0045] Figure 8 For Figure 7 Structure diagram of the middle central pipe.

[0046] Figure 9 For Figure 7 Structure diagram of the middle upper pushing cylinder.

[0047] Figure 10 For Figure 7 Structure diagram of the middle flow limiting plate.

[0048] Figure 11 For Figure 7 Structure diagram of the middle lower outer cylinder.

[0049] Figure 12 For Figure 7 Structure diagram of the middle lower pushing cylinder.

[0050] Figure 13 For Figure 7 Structure diagram of the middle limiting cylinder.

[0051] Figure 14 For Figure 1 Structure diagram of the middle downhole gas-solid separator.

[0052] Figure 15 For Figure 14 Structure diagram of the middle cyclone vane.

[0053] In the figure: preset working cylinder 1, sealing working cylinder 2, small diameter oil pipe 3, downhole annular space flow limiting device 4, large diameter oil pipe 5, downhole safety valve 6, flow short section 7, centralizer 8, small diameter thickened oil pipe 9, downhole gas-solid separator 10; preset working cylinder 1: preset upper outer cylinder 1-1, upper outer cylinder torque transmission spline 1-11; preset locking ring 1-2, locking ring torque transmission spline 1-21; preset lower outer cylinder 1-3.

[0054] Sealing working barrel 2: inner barrel 2-1, backwashing hole 2-101, sealing ring groove one 2-102, limiting step one 2-103, backwashing control hole 2-104, sealing ring groove two 2-105, limiting step two 2-106, limiting step three 2-107, limiting step four 2-108, middle locking ring connecting thread 2-109, limiting step five 2-110; upper locking ring 2-2, working barrel sliding barrel 2-3, working barrel spring 2-4, disc spring 2-5, disc spring top ring 2-6, sealing plug 2-7, middle locking ring 2-8, working barrel limiting ring 2-9, sealing assembly 2-10, sealing compression ring 2-11, lower compression ring 2-12; downhole annular flow limiting device 4, upper joint 4-1, central pipe 4-2, limiting plate mounting groove 4-2-1, seat sealing hole 4-2-2, locking ring groove 4-2-3, seat sealing boost hole 4-2-4, locking ring mounting groove 4-2-5, upper push barrel limiting step 4-2-6, continuation thread 4-2-7, flow limiting device sliding barrel 4-3, locking ring 4-4, flow limiting device limiting ring 4-5, leather cup 4-6, upper push barrel 4-7, retreat stop thread 4-7-1, upper barrel body 4-7-2, flow limiting device locking ring 4-8, flow limiting device upper outer barrel 4-9, flow limiting plate 4-10, main channel groove 4-10-1, auxiliary channel groove 4-10-2, flow limiting device lower outer barrel 4-11, inner taper matching surface 4-11-1, lower push barrel 4-12, outer taper matching surface 4-12-1, flow limiting device spring 4-13, limiting barrel 4-14, flow limiting device lower outer barrel 4-11, inner taper matching surface 4-11-1, lower push barrel 4-12, outer taper matching surface 4-12-1, flow limiting device spring 4-13, limiting barrel 4-14, backwashing and blowout prevention flow passage 4-14-1;

[0055] Downhole gas-solid separator 10: separator upper joint 10-1, outer shell 10-2; sand filter barrel 10-3, centralizer 10-3-1, cyclone vane 10-4, separator lower joint 10-5. DETAILED DESCRIPTION

[0056] The accompanying drawings are only used for reference and illustration, and are not used to limit the protection scope of the present application. The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the present application.

[0057] In order to make the purpose, technical solutions and advantages of the present application more clear and explicit, the present application will be further described in detail in combination with the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not used to limit the present application.

[0058] In the description of the present application, it should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0059] Referring to Figures 1-13 A compressed air energy storage horizontal well high-frequency injection and production pipe string is provided with a tubing and a downhole safety valve 6, wherein: the injection and production pipe string is connected with a downhole combined sealing device, a downhole annular flow limiting device 4 and the downhole safety valve 6 in sequence from bottom to top through the tubing, the downhole combined sealing device is inserted and connected by a preset working barrel 1 and a sealing working barrel 2; in the preset working barrel 1, a preset locking ring 1-2 with a dog tooth is installed between a preset upper outer barrel 1-1 and a preset lower outer barrel 1-3, the preset upper outer barrel 1-1 is connected with the preset lower outer barrel 1-3, and the preset working barrel (1) is advanced into a preset horizontal section in the well with a well completion pipe string; the sealing working barrel 2 includes a sealing part mainly composed of a sealing insertion barrel 2-7 and a sealing assembly 2-10, and an inner barrel 2-1; the inner barrel 2-1 is provided with a backwashing hole 2-101 and a backwashing control hole 2-104, and the outer circle of a limiting step three 2-107 in the inner barrel 2-1 is processed with a dog tooth; the sealing working barrel 2 is connected at the lower end of the injection and production pipe string and is inserted into the preset working barrel 1, the inner barrel 2-1 is matched with the dog tooth in the preset locking ring 1-2, the sealing insertion barrel 2-7 seals a sealing insertion barrel sealing cavity of the preset lower outer barrel 1-3, and the sealing assembly 2-10 seals a sealing piece sealing cavity of the preset lower outer barrel 1-3; the downhole annular flow limiting device 4 is provided with a leather cup 4-6 and a central pipe 4-2, a flow limiting plate 4-10 of a staggered converging flow channel is fixed in a flow limiting plate mounting groove 4-2-1 in the wall of the central pipe 4-2 and is provided with a seat sealing hole 4-2-2 and a seat sealing boost hole 4-2-4 in the wall without the flow limiting plate mounting groove 4-2-1; above a top pushing barrel limiting step 4-2-6 of the central pipe 4-2, a flow limiting device sliding barrel 4-3, the leather cup 4-6 and an upper top pushing barrel 4-7 are installed in sequence from top to bottom; the flow limiting device sliding barrel 4-3 above the leather cup 4-6 is internally provided with a flow limiting device limiting ring 4-5 on which a locking ring 4-4 is installed, and the locking ring 4-4 is installed in a locking ring groove 4-2-3 of the outer circle of the central pipe 4-2; the upper top pushing barrel 4-7 is matched with a flow limiting device locking ring 4-8 installed in a locking ring mounting groove 4-2-5 of the central pipe 4-2 through a dog tooth.

[0060] The downhole combined sealing device in the application is composed of two parts, pre-setting working barrel 1 and sealing working barrel 2, and is used in cooperation. The inner wall of pre-setting locking ring 1-2 in pre-setting working barrel 1 is processed with a ratchet, and the upper end is processed with locking ring torque transmission spline 1-21 matched with upper outer barrel torque transmission spline 1-11 in pre-setting upper outer barrel 1-1. The two are matched through spline to realize torque transmission function. The ratchet of the inner wall of pre-setting locking ring 1-2 is matched with the ratchet in inner barrel 2-1 to realize axial one-way locking function.

[0061] According to the process requirement, when the cup 4-6 is seated, the liquid flows from the inside of the oil pipe through the seat hole 4-2-2 into the gap between the flow limiting device sliding cylinder 4-3 and the flow limiting device limiting ring 4-5, pushes the flow limiting device sliding cylinder 4-3 to move upward, and the cup 4-6 is released from the flow limiting device sliding cylinder 4-3. With the liquid entering through the seat hole 4-2-4, the upper pushing cylinder 4-7 moves upward and pushes the cup 4-6 to death in the oil jacket annulus, realizing the isolation between the flow limiting device sliding cylinder 4-3 and the casing. At this time, the reverse well washing operation can be carried out through the staggered collection flow channel in the flow limiting plate 4-10.

[0062] When the well bottom pressure rises and blowout occurs, the well fluid is blocked from flowing upward through the staggered collection flow channel in the flow limiting plate 4-10, effectively slowing down the flow speed of the well fluid and weakening the intensity of the blowout, which gives valuable time for the ground to fight the blowout.

[0063] The flow limiting plate 4-10 in the device is provided with a staggered collection flow channel and is fixed in the flow limiting plate mounting groove 4-2-1 in the wall of the central pipe 4-2. The seat hole 4-2-2 and the seat hole 4-2-4 are arranged in the wall of the central pipe 4-2 without the flow limiting plate mounting groove 4-2-1.

[0064] The cup 4-6 is installed in the flow limiting device sliding cylinder 4-3 and the lower part is located between the flow limiting device sliding cylinder 4-3 and the upper pushing cylinder 4-7. The flow limiting device limiting ring 4-5 installed with the lock ring 4-4 is installed in the flow limiting device sliding cylinder 4-3 above the cup 4-6. The lock ring 4-4 installed in the lock ring groove 4-2-3 of the outer circle of the central pipe 4-2 locks the flow limiting device limiting ring 4-5 at the inner top end of the flow limiting device sliding cylinder 4-3 outside the central pipe 4-2. The flow limiting device locking ring 4-8 is installed in the locking ring mounting groove 4-2-5 of the central pipe 4-2 and is matched with the upper pushing cylinder 4-7 through the ratchet. The flow limiting device locking ring 4-8 is fixed in the locking ring mounting groove 4-2-5 and cannot move axially. The upper pushing cylinder 4-7 can move upward along the flow limiting device locking ring 4-8, expand the cup 4-6, and seal the annulus between the flow limiting device sliding cylinder 4-3 and the casing.

[0065] The downhole annular flow limiting device 4 can not only backwash the well while sealing the oil sleeve annulus by using the leather cup 4-6, but also can throttle and flow limit the upwelling well fluid through the flow limiting plate 4-10, and is connected in the injection and production pipe column through the upper joint 4-1.

[0066] The downhole annular flow limiting device 4 can control blowout of the gas storage injection and production well, increase a safety guarantee, avoid adverse consequences caused by blowout, improve economic benefits and has remarkable use effect.

[0067] On the basis of the above-mentioned embodiment one, the application also has the following embodiments:

[0068] A preferred embodiment: the sealing working barrel 2 is further provided with an upper locking ring 2-2, a working barrel sliding barrel 2-3, a working barrel spring 2-4, a disc spring 2-5, a middle locking ring 2-8 and a sealing compression ring 2-11, the upper locking ring 2-2, the working barrel sliding barrel 2-3 and the working barrel spring 2-4 are sequentially installed above the limiting step three 2-107 from top to bottom, the disc spring 2-5, the sealing insert barrel 2-7, the middle locking ring 2-8, the sealing assembly 2-10 and the sealing compression ring 2-11 are sequentially installed below the limiting step three 2-107 from top to bottom. The sealing working barrel 2 connected with the preset working barrel 1 is below the limiting step three 2-107 tightly connected with the dog tooth buckle, and is further provided with the disc spring 2-5 and the disc spring top ring 2-6, the disc spring top ring 2-6 can effectively transmit axial pressure, compress the disc spring 2-5 and store a certain tonnage of pressure when the injection and production pipe column is pressed down, the dog tooth buckle between the preset working barrel 1 and the sealing working barrel 2 can be prevented from creeping within a pitch range, and the middle locking ring 2-8 threadedly connected with the inner barrel 2-1 is further arranged below the sealing insert barrel 2-7 to limit and tightly press the sealing insert barrel 2-7.

[0069] A preferred embodiment: the ring body top of the preset locking ring 1-2 is provided with a locking ring torque transmission spline 1-21, the lower inner circle of the preset locking ring 1-2 is provided with a dog tooth buckle, and the preset locking ring 1-2 is an open ring with straight or inclined through grooves opened axially; the preset upper outer barrel 1-1 is a non-equal-diameter cylindrical body, the upper inner cavity of the preset upper outer barrel 1-1 is provided with an inner thread connected with the well completion pipe column, the lower inner cavity is a threaded inner cavity, the middle inner cavity is provided with a locking ring limiting step, and the inner circle of the locking ring limiting step is provided with an upper outer barrel torque transmission spline 1-11; the upper outer barrel torque transmission spline 1-11 can cooperate with the locking ring torque transmission spline 1-21 at the ring body top of the preset locking ring 1-2, and the preset locking ring 1-2 after cooperation is just located in the locking ring mounting cavity between the locking ring limiting step and the threaded inner cavity of the lower part.

[0070] A preferred embodiment: the preset lower outer cylinder 1-3 is a non-equal diameter cylindrical body, both ends of the preset lower outer cylinder 1-3 are provided with external threads and can be respectively connected with the internal threads in the threaded inner cavity of the lower part of the preset upper outer cylinder 1-1 and the lower casing thread in the completion string; the upper inner cavity of the preset lower outer cylinder 1-3 is a sealing sleeve sealing cavity, and the lower inner cavity is a sealing element sealing cavity; the sealing sleeve sealing cavity is a conical cavity.

[0071] A preferred embodiment: the sealing sleeve 2-7 can be made of rubber or high polymer material, soft metal or memory alloy material, the lower outer circle of the sealing sleeve 2-7 is a conical outer circle which cooperates with the sealing sleeve sealing cavity of the preset lower outer cylinder 1-3; a disc spring top ring 2-6 is further arranged between the disc spring 2-5 and the sealing sleeve 2-7. The high polymer material includes engineering resin and engineering plastic, and the soft metal includes copper and lead. The disc spring top ring 2-6 can protect the top end of the sealing sleeve 2-7 and provide a tightening force to prevent the loosening of the cog when working, thereby improving and strengthening the tightening effect of the disc spring 2-5 on the sealing sleeve 2-7 and further improving the sealing effect.

[0072] A preferred embodiment: the inner cylinder 2-1 is a non-equal diameter cylindrical body, the upper and lower ends of the inner cylinder 2-1 are respectively provided with injection-production string connecting threads and spare part connecting threads; the outer circle of the inner cylinder 2-1 is sequentially provided with a limiting step one 2-103, a limiting step two 2-106, a limiting step three 2-107, a limiting step four 2-108 and a limiting step five 2-110 from top to bottom, and the outer circles of the limiting step one 2-103, the limiting step two 2-106, the limiting step three 2-107, the limiting step four 2-108 and the limiting step five 2-110 are all precisely processed outer circle surfaces.

[0073] A preferred embodiment: the backwashing hole 2-101 and the backwashing control hole 2-104 are arranged in the limiting step one 2-103, the backwashing hole 2-101 is arranged in the outer circle below the injection-production string connecting threads and sealing rings are arranged on both sides of the backwashing hole 2-101; the backwashing control hole 2-104 is arranged at the root of the limiting step one 2-103 and at least one sealing ring groove two 2-105 is arranged on the top outer circle of the limiting step two 2-106; the limiting step three 2-107 has the largest outer diameter and has a cog processed on the outer circle, a middle locking ring connecting thread 2-109 is arranged at the lower end of the outer circle of the limiting step four 2-108; a spare part connecting thread is processed on the lower part of the limiting step five 2-110.

[0074] A preferred embodiment: the center lock ring 2-8 is provided with a center hole and the inner circle is provided with threads, and after the center lock ring 2-8 is sleeved on the outside of the inner cylinder 2-1, the internal threads of the inner circle are threadedly connected with the center lock ring connecting threads 2-109, thereby providing support for the sealing plug 2-7; the sealing assembly 2-10 is a combined seal, which at least includes a sealing ring and a polytetrafluoroethylene-made protective ring installed on both sides of the sealing ring, respectively, and the outer diameter of the sealing ring is greater than the inner diameter of the sealing cavity of the preset lower outer cylinder 1-3; the sealing compression ring 2-11 is threadedly connected with the spare part connecting threads of the lower part of the limiting step five 2-110, and the lower compression ring 2-12 and the dissolvable plug are further connected below the sealing compression ring 2-11, thereby further providing compression and locking force for the sealing assembly 2-10 and the sealing compression ring 2-11 and preventing the sealing compression ring 2-11 from loosening.

[0075] A preferred embodiment: the inner circle of the working cylinder sliding cylinder 2-3 is processed into two sections of inner diameters with the small section being on the outside of the limiting step one 2-103 of the inner cylinder 2-1 and the large section being on the outside of the limiting step two 2-106; both sections of the inner circle of the working cylinder sliding cylinder 2-3 are precision finished surfaces; in the normal working state, the small section of the working cylinder sliding cylinder 2-3 blocks the backwashing hole 2-101, and the large section is in communication with the backwashing control hole 2-104. In the process of backwashing, pumping casing protection fluid into the annulus between the oil jacket and the casing, and reverse circulation well killing, under the action of pressure difference, the working cylinder sliding cylinder 2-3 moves downward to expose the backwashing hole 2-101, forming a backwashing channel; the backwashing control hole 2-104 discharges the liquid in the inner cavity of the working cylinder sliding cylinder 2-3 to the inside of the oil pipe, preventing the formation of a dead space and hindering the downward movement of the working cylinder sliding cylinder 2-3 when it moves downward. After the backwashing operation is completed, under the pushing force of the working cylinder spring 2-4, the working cylinder sliding cylinder 2-3 moves upward and closes the backwashing hole 2-101, sealing the oil jacket communication channel.

[0076] In addition to the sealing plug 2-7 being able to achieve sealing between the preset working cylinder 1 and the sealing working cylinder 2, the sealing assembly 2-10 is further provided below the sealing plug 2-7, which at least includes a sealing ring and two protective rings, thereby further providing a sealing barrier for the device, ensuring the sealing effect of the device, prolonging the service life of the sealing tool and the injection-production pipe column, and reducing production costs.

[0077] The working principle of the downhole combined sealing device is to first fix the preset working cylinder 1 downhole, and then connect the sealing working cylinder 2 to the lowermost end of the injection-production pipe column, and then lower the injection-production pipe column into the well.

[0078] When the sealing working barrel 2 is inserted into the pre-working barrel 1, the sealing insert barrel 2-7 and the sealing assembly 2-10 cooperate with the corresponding sealing surface in the pre-working barrel 1 to achieve the sealing of the oil jacket annulus; at the same time, the external wall of the limiting step three 2-107 of the inner barrel 2-1 of the sealing working barrel 2 cooperates with the pre-locking ring 1-2 in the pre-working barrel 1 to achieve axial locking; in addition, a part of the injection and production string is pressed down, and the tonnage is transmitted to the disc spring 2-5 through the sealing insert barrel 2-7, the disc spring 2-5 is compressed and stores a certain tonnage of pressure, preventing the ratchet from creeping within one pitch.

[0079] The disc spring 2-5 can always ensure the tension of the ratchet in the pre-working barrel 1 and the sealing working barrel 2, and reduce the damage of the sealing assembly 2-10 caused by the creep of the injection and production string. The sliding sleeve 2-3 is in a closed state during normal operation, and when the injection and production string needs to be backwashed, pumped into the casing protection fluid or encounters a well blowout accident, the well washing fluid or the kill fluid can be pumped into the oil jacket annulus, providing a process channel for the cleaning or well killing operation of the injection and production string.

[0080] A preferred embodiment is shown in Figure 7 , Figure 8 and Figure 10 The skin bowl 4-6 is installed in the flow limiting device sliding barrel 4-3 and the lower part is located between the flow limiting device sliding barrel 4-3 and the upper pushing barrel 4-7, and the sealing surface of the outer circle of the center pipe 4-2 is installed with a sealing element; the staggered collection flow channel is composed of the main channel groove 4-10-1 processed in the center of the flow limiting plate 4-10 and the auxiliary channel groove 4-10-2 connected with the main channel groove 4-10-1; the limiting plate installation groove 4-2-1 and the flow limiting plate 4-10 provided on the outer wall of the center pipe 4-2 are set in more than one set, and the flow limiting plate 4-10 is welded in the limiting plate installation groove 4-2-1.

[0081] A preferred embodiment is shown in Figure 7 , Figure 8 and Figure 10 The main channel groove 4-10-1 is a straight groove passing through both ends of the flow limiting plate 4-10; the auxiliary channel groove 4-10-2 is arranged on both sides of the main channel groove 4-10-1 and has an arc-shaped downward inclined shape, and the auxiliary channel grooves 4-10-2 on both sides are connected in a staggered manner in the main channel groove 4-10-1. The staggered collection flow channel in the flow limiting plate 4-10 can also have other forms and structures, and in principle, the liquid flow from above the invention should flow smoothly, and the liquid flow from below the invention should be difficult to return upward.

[0082] In a preferred embodiment: both the locking ring 4-4 ​​and the flow-limiting device locking ring 4-8 are broken rings with axial cuts. The axial cuts are either oblique cuts or vertical cuts with an angle between 1 degree and 89 degrees. The inner diameter of the locking ring 4-4 ​​in its natural state is smaller than the outer diameter of the central pipe 4-2 section it is in. This is mainly to take into account installation issues. The inner diameter of the locking ring 4-4 ​​is slightly smaller than the outer diameter of the upper part of the central pipe 4-2. After installation and restoration, it can still be locked in the locking ring groove 4-2-3. The outer circle of the flow-limiting device locking ring 4-8 is machined with toothed threads and can cooperate with the toothed threads machined on the inner circle of the upper push cylinder 4-7.

[0083] In a preferred embodiment: the upper push cylinder 4-7 is a non-uniform diameter cylindrical body, having an upper cylinder 4-7-2 and a backstop thread 4-7-1 disposed in the lower cylinder. The inner diameter of the upper cylinder 4-7-2 is smaller than the inner diameter of the lower cylinder. At least one sealing liquid passage groove 4-7-3 is provided on the outer wall of the upper cylinder 4-7-2, and the sealing liquid passage groove 4-7-3 communicates with the top of the upper cylinder 4-7-2. The inner circle of the lower cylinder of the upper push cylinder 4-7 is provided with a backstop thread 4-7-1, which is a toothed thread and can engage with the toothed thread on the outer circle of the locking ring 4-8 of the flow limiting device.

[0084] In a preferred embodiment, the outer circle of the central tube 4-2 below the upper push cylinder limiting step 4-2-6 is machined with a continuing thread 4-2-7, which can be threadedly connected to the washing and anti-spray mechanism.

[0085] A preferred embodiment: See Figure 12 The anti-spray mechanism includes an upper outer cylinder 4-9 of the flow limiting device, a lower outer cylinder 4-11 of the flow limiting device, a lower push cylinder 4-12, a spring 4-13 of the flow limiting device, and a limiting cylinder 4-14. The two ends of the upper outer cylinder 4-9 of the flow limiting device are respectively threaded to the continuation thread 4-2-7 in the central tube 4-2 and the lower outer cylinder 4-11 of the flow limiting device. The lower push cylinder 4-12 and the spring 4-13 of the flow limiting device are installed inside the lower outer cylinder 4-11 of the flow limiting device. The limiting cylinder 4-14 is installed below the spring 4-13 of the flow limiting device and is threaded to the lower outer cylinder 4-11 of the flow limiting device. The limiting cylinder 4-14 is provided with at least one anti-spray liquid passage groove 4-14-1. This prevents incoming water and liquid from below the annular flow restrictor from entering the upper part of the annular flow restrictor through the lower push cylinder 4-12, while allowing incoming water and liquid from above the annular flow restrictor to enter the lower part of the annular flow restrictor by pushing open the lower push cylinder 4-12 held in place by the spring 4-13 of the flow restrictor.

[0086] A preferred embodiment: See Figure 11, the inner circle of the lower outer cylinder 4-11 of the flow limiting device is a non-equal-diameter inner circle, and the internal threads at both ends are respectively threadedly connected with the upper outer cylinder 4-9 and the limiting cylinder 4-14 of the flow limiting device; the inner tapered matching surface 4-11-1 is arranged between the two outer non-equal-diameter inner circles of the lower outer cylinder 4-11 of the flow limiting device, and the inner tapered matching surface 4-11-1 is a lower inclined surface.

[0087] A preferred embodiment is shown in the following table: Figure 12 , the lower pushing cylinder 4-12 is a non-equal-diameter cylindrical body, the upper outer wall of the lower pushing cylinder 4-12 is an outer tapered matching surface 4-12-1, the outer tapered matching surface 4-12-1 is an upper inclined surface and can be matched with the inner tapered matching surface 4-11-1 in the lower outer cylinder 4-11 of the flow limiting device, and at least one sealing ring groove is processed in the outer tapered matching surface 4-12-1; the spring 4-13 of the flow limiting device is installed in the inner cavity below the spring limiting step 4-12-2 in the lower pushing cylinder 4-12.

[0088] A preferred embodiment is shown in the following table: Figure 13 , the upper outer circle of the limiting cylinder 4-14 is provided with external threads and can be threadedly connected with the lower outer cylinder 4-11 of the flow limiting device; the washing and anti-spray overflow liquid groove 4-14-1 arranged in the outer wall of the limiting cylinder 4-14 is a through groove from top to bottom and at least one groove is arranged; the upper outer cylinder 4-9 of the flow limiting device is a non-equal-diameter cylindrical body, and the internal and external threads in the cylinder bodies at the upper and lower ends can be respectively threadedly connected with the continuation threads 4-2-7 of the central pipe 4-2 and the lower outer cylinder 4-11 of the flow limiting device, and the lower inner cavity of the upper outer cylinder 4-9 of the flow limiting device after being connected with the central pipe 4-2 is in communication with the limiting plate mounting groove 4-2-1. In the annular flow limiting device, sealing elements are arranged in the sealing matching surfaces between the components.

[0089] The washing and anti-spray mechanism connected with the lower part of the central pipe 4-2 adds another protection for the blowout prevention and the limited flow throttling when the well kicks and the well blows. The water from the reverse well washing above the device can increase the pump pressure, push away the lower pushing cylinder 4-12, and spray from the washing and anti-spray overflow liquid groove 4-14-1 to the oil-casing annulus to perform reverse circulation well washing.

[0090] When the downhole pressure increases and the well blows, due to the isolation of the cup 4-6 and the inner and outer tapered matching surfaces in the lower outer cylinder 4-11 and the lower pushing cylinder 4-12 of the flow limiting device, the water and liquid cannot return from the washing and anti-spray overflow liquid groove 4-14-1 of the limiting cylinder 4-14; if the washing and anti-spray mechanism fails, the inner and outer tapered matching surfaces in the lower outer cylinder 4-11 and the lower pushing cylinder 4-12 of the flow limiting device cannot be sealed and cannot realize the one-way flow control function, and the liquid flow can only pass through the staggered collection flow channels in the flow limiting plate 4-10, and when the liquid passes through the staggered collection flow channels, due to the mutual impact of the liquid flow directions in the main channel groove 4-10-1 and the auxiliary channel groove 4-10-2, the upwelling flow and pressure are greatly reduced, which gives more time for the ground workers to prevent the blowout.

[0091] A preferred embodiment: the high-frequency injection and production string in the straight well section on both sides of the downhole annulus flow-restricting device 4 is connected with a centralizer 8, and the high-frequency injection and production string in the straight well section on both sides of the downhole safety valve 6 is connected with a flow sub 7; the tubing includes a small-diameter tubing 3, a large-diameter tubing 5, and a small-diameter thickened tubing 9, the centralizer 8 and the downhole annulus flow-restricting device 4 are connected in series in the small-diameter tubing 3, the downhole safety valve 6 and the flow sub 7 are connected in series in the large-diameter tubing 5, and the small-diameter thickened tubing 9 and the downhole gas-solid separator 10 are connected in series between the small-diameter tubing 3 and the sealing working barrel 2. The tubing includes a small-diameter tubing 3, a large-diameter tubing 5, and a small-diameter thickened tubing 9, the centralizer 8 and the downhole annulus flow-restricting device 4 are connected in series in the small-diameter tubing 3, the downhole safety valve 6 and the flow sub 7 are connected in series in the large-diameter tubing 5. The downhole safety valve 6 is provided with flow subs 7 at both ends to ensure the stability of the fluid flow in the tubing. The downhole annulus flow-restricting device 4 is provided with centralizers 8 at both ends to improve the centralization of the device and ensure the normal operation of the device. The tubing is provided with three types, the small-diameter thickened tubing 9 is connected in the injection and production string in the hole-shaping section, the small-diameter tubing 3 is connected in the middle of the string, and the large-diameter tubing 5 is connected in the upper part of the string, so as to adjust the pressure by changing the flow area of the fluid and slow down the formation of scale.

[0092] A preferred embodiment: the downhole gas-solid separator 10 is provided with a separator upper connector 10-1, an outer shell 10-2, a sand filter 10-3, a cyclone vane 10-4, and a separator lower connector 10-5, the sand filter 10-3 with a centralizing vane 10-3-1 and the cyclone vane 10-4 are respectively installed in the upper part and the lower part of the outer shell 10-2, the separator upper connector 10-1 is threadedly connected with the sand filter 10-3 and a sealing ring is installed between the upper end of the outer shell 10-2 and the sand filter 10-3, the outer shell 10-2 is threadedly connected with the separator lower connector 10-5 at the lower part and a sealing ring is installed, and the cyclone vane 10-4 is blocked in the outer shell 10-2.

[0093] A preferred embodiment: the inner cavity of the upper part of the outer shell 10-2 is larger than that of the lower part, a tapered transition cavity is arranged in the middle of the inner cavity, a hole or a groove is arranged in the barrel of the sand filter 10-3, the centralizing vane 10-3-1 is arranged at the lower end of the barrel of the sand filter 10-3 and is equal to or larger than the maximum inner diameter of the tapered transition cavity in the outer shell 10-2, the sand filter 10-3 is a barrel structure, the upper end is processed with threads to be connected with the separator upper connector 10-1, and the sand filter 10-3 in the application adopts a slotted screen pipe, but is not limited to the slotted screen pipe, and can be a screen cloth type or a pre-packed sand filter structure; the cyclone vane 10-4 is a twisted plate structure, and the equivalent circle outer diameter after twisting, the pitch after twisting, and the thickness of the plate are matched with the spiral groove processed in the lower part of the inner cavity of the outer shell 10-2.

[0094] The working principle of the downhole gas-solid separator 10 is that when fluid is produced, it passes through the cyclone plate 10-4 at high speed, causing the fluid to rotate at high speed while advancing, and due to the different densities of gas and solids, the small sand particles in the gas flow are thrown to the periphery into the sand storage cavity of the outer shell 10-2 under the action of centrifugal force, thereby reducing the erosion of the high-speed gas flow on the inner wall of the tubing in the build-up section.

[0095] The well completion method applied to the high-frequency injection and production string of the compressed air energy storage horizontal well comprises the following steps: A, the pre-set working barrel 1 in the downhole combined sealing device is connected in series at a predetermined position in the well completion string and is lowered into the well for completion; B, the sealing working barrel 2 is connected to the lower end of the injection and production string and is lowered into the well, and the sealing working barrel 2 is pressed down through the injection and production string to anchor and seal the injection and production string and the well completion string; C, the downhole annulus flow limiting device is positively pressure tested and sealed, and whether the injection and production string leaks is tested at the same time; during the process, if the injection and production string leaks in the positive rotation, the injection and production string is replaced.

[0096] D, if the injection and production string does not leak in the pressure test, the downhole annulus flow limiting device 4 is started; during the process, the connection sleeve valve pipeline is pressed by the oil-casing annulus, and the downhole annulus flow limiting device 4 is started, and if the pressure suddenly drops, it proves that the starting is successful.

[0097] E, after the downhole annulus flow limiting device 4 is started, the reverse well flushing is continued to verify whether the downhole combined sealing device works normally; during the process, if there is return fluid in the wellhead tubing, it proves that the reverse washing channel in the downhole combined sealing device is normally opened; then the well flushing pipeline is reversed to the positive washing process for pressure testing, and if the pressure does not decrease to the predetermined value, it proves that the reverse washing channel in the downhole combined sealing device is normally closed.

[0098] F, after the downhole combined sealing device is verified to work normally, the casing protection liquid is injected; during the process, the well flushing pipeline is reversed to the reverse washing process, and the quantitative casing protection liquid is injected into the oil-casing annulus.

[0099] G, the well flushing pipeline is reversed to the positive washing process, the ground pressure is tested after a period of time, the soluble plug in the downhole combined sealing device is broken, and the well completion of the high-frequency injection and production string of the horizontal well is realized. If there is any abnormal condition in the above process steps, the injection and production string needs to be replaced in the positive rotation.

[0100] The working principle of the injection and production string is that after the normal injection and production cycle is completed, the injection and production string is cleaned inside by the reverse well flushing method with the descaling, derusting and de-waxing liquid, so as to prevent a large amount of scale from blocking the injection and production string channel due to the high strength and high frequency of the injection and production air, and the annulus casing protection liquid is replaced, so as to reduce the cost and time of replacing the injection and production string, prolong the service life of the injection and production string, and improve the use efficiency of the gas storage.

[0101] The above-described embodiments are merely typical embodiments of the present application, but the present application is not limited to these embodiments. Those skilled in the art can make modifications to the technical solutions recorded in the above-described embodiments, or make equivalent replacements to some of the technical features, without departing from the spirit and essence of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and essence of the present application shall be included in the protection scope of the present application. Therefore, the protection scope is not limited to the above description.

Claims

1. A high-frequency injection-production tubing string for a compressed air energy storage horizontal well, equipped with tubing and a downhole safety valve (6), characterized in that, The injection and production tubing string is connected from bottom to top to the downhole combined sealing device, the downhole annular flow limiting device (4), and the downhole safety valve (6) via tubing. The downhole combined sealing device is formed by inserting a pre-set working cylinder (1) and a sealing working cylinder (2). In the pre-set working cylinder (1), a pre-set locking ring (1-2) with a toothed buckle is installed between the pre-set upper outer cylinder (1-1) and the pre-set lower outer cylinder (1-3). The pre-set upper outer cylinder (1-1) is connected to the pre-set lower outer cylinder (1-3). The pre-set working cylinder (1) is lowered into the preset horizontal section in the well in advance with the completion tubing string. The sealing working cylinder (2) mainly consists of a sealing insert (2-7). The sealing component consists of a sealing assembly (2-10) and an inner cylinder (2-1); the inner cylinder (2-1) is provided with a backwash hole (2-101) and a backwash control hole (2-104), and the outer circle of the limiting step three (2-107) in the inner cylinder (2-1) is machined with a toothed thread; the sealing working cylinder (2) is connected to the lower end of the injection and production tubing and lowered into the pre-set working cylinder (1), the inner cylinder (2-1) is connected to the toothed thread in the pre-set locking ring (1-2), the sealing insert (2-7) seals the sealing insert sealing cavity of the pre-set lower outer cylinder (1-3), and the sealing assembly (2-10) seals the sealing element of the pre-set lower outer cylinder (1-3). The wellbore annular flow limiting device (4) is equipped with a cup (4-6) and a central tube (4-2). The flow limiting plate (4-10) of the intersecting and converging flow channels is fixed in the flow limiting plate mounting groove (4-2-1) in the wall of the central tube (4-2). A sealing hole (4-2-2) and a sealing booster hole (4-2-4) are provided in the wall of the tube without the flow limiting plate mounting groove (4-2-1). Above the upper push cylinder limiting step (4-2-6) of the central tube (4-2), the flow limiting device slide cylinder (4-3), the cup (4-6) and the upper push cylinder (4-7) are installed from top to bottom. The flow limiting device above the cup (4-6) is... The sliding cylinder (4-3) contains a flow limiting device limiting ring (4-5) with a locking ring (4-4) installed inside. The locking ring (4-4) is installed in the locking ring groove (4-2-3) on the outer circle of the central tube (4-2). The upper push cylinder (4-7) and the flow limiting device locking ring (4-8) installed in the locking ring mounting groove (4-2-5) of the central tube (4-2) are engaged by a toothed thread. The oil pipe includes a small diameter oil pipe (3), a large diameter oil pipe (5) and a small diameter thickened oil pipe (9). The small diameter thickened oil pipe (9) and the downhole gas-solid separator (10) are connected in series between the small diameter oil pipe (3) and the sealing working cylinder (2).

2. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 1, characterized in that, The sealing working cylinder (2) is also provided with an upper locking ring (2-2), a working cylinder slide (2-3), a working cylinder spring (2-4), a disc spring (2-5), a middle locking ring (2-8), and a sealing pressure ring (2-11). The upper locking ring (2-2), the working cylinder slide (2-3), and the working cylinder spring (2-4) are installed in sequence from top to bottom above the limiting step three (2-107); the disc spring (2-5), the sealing insert (2-7), the middle locking ring (2-8), the sealing assembly (2-10), and the sealing pressure ring (2-11) are installed in sequence from top to bottom below the limiting step three (2-107).

3. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 2, characterized in that, The pre-set locking ring (1-2) has a locking ring transmission spline (1-21) at the top of its ring body, and a toothed thread on the lower inner circle of the pre-set locking ring (1-2). The pre-set locking ring (1-2) is an open ring with a straight or oblique through groove in the axial direction. The pre-set upper outer cylinder (1-1) is a non-uniform diameter cylindrical body. The upper inner cavity of the pre-set upper outer cylinder (1-1) has an internal thread for connection with the completion tubing string. The lower part is a threaded inner cavity, and the middle inner cavity has a locking ring limiting step. The upper outer cylinder transmission spline (1-11) is located on the inner circle of the locking ring limiting step. The upper outer cylinder transmission spline (1-11) can cooperate with the locking ring transmission spline (1-21) at the top of the pre-set locking ring (1-2). After cooperation, the pre-set locking ring (1-2) is located in the locking ring mounting cavity between the locking ring limiting step and the lower threaded inner cavity.

4. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 3, characterized in that, The pre-set lower outer cylinder (1-3) is a non-uniform diameter cylindrical body. Both ends of the pre-set lower outer cylinder (1-3) are provided with external threads and can be connected to the internal threads in the threaded inner cavity of the lower part of the pre-set upper outer cylinder (1-1) and the lower casing thread in the completion string, respectively. The upper inner cavity of the pre-set lower outer cylinder (1-3) is a sealing insert sealing cavity, and the lower inner cavity is a sealing element sealing cavity. The sealing insert sealing cavity is a conical cavity.

5. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 2, characterized in that, The sealing insert (2-7) can be made of polymer material, soft metal or shape memory alloy. The lower outer circle of the sealing insert (2-7) is a conical outer circle, which cooperates with the sealing cavity of the pre-set lower outer cylinder (1-3). A disc spring top ring (2-6) is also installed between the disc spring (2-5) and the sealing insert (2-7).

6. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 5, characterized in that, The inner cylinder (2-1) is a non-uniform diameter cylindrical body. The upper and lower ends of the inner cylinder (2-1) are respectively provided with injection and extraction tubing connection threads and spare parts connection threads. The outer circle of the inner cylinder (2-1) is provided with limiting steps one (2-103), two (2-106), three (2-107), four (2-108), and five (2-110) from top to bottom. The outer circles of the limiting steps one (2-103), two (2-106), three (2-107), four (2-108), and five (2-110) are all precision machined outer circles.

7. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 6, characterized in that, The backwash hole (2-101) and backwash control hole (2-104) are located in the first limiting step (2-103). The backwash hole (2-101) is located in the outer circle below the injection and production tubing connection thread, and a sealing ring groove and a sealing ring are provided on the upper and lower sides of the backwash hole (2-101). The backwash control hole (2-104) is located at the root of the first limiting step (2-103), and at least one sealing ring groove (2-105) is provided on the top outer circle of the second limiting step (2-106). The third limiting step (2-107) has the largest outer diameter and has a toothed thread machined on its outer circle. A central locking ring connection thread (2-109) is provided at the lower end of the outer circle of the fourth limiting step (2-108). A spare component connection thread is machined at the lower part of the fifth limiting step (2-110).

8. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 7, characterized in that, The central locking ring (2-8) has a central hole and an inner thread. After the central locking ring (2-8) is fitted outside the inner cylinder (2-1), the inner thread of its inner circle is threadedly connected to the central locking ring connecting thread (2-109). The sealing assembly (2-10) is a combined sealing element, which includes at least one sealing ring and protective rings made of polytetrafluoroethylene respectively installed on both sides of the sealing ring. The outer diameter of the sealing ring is larger than the inner diameter of the sealing cavity of the sealing element in the pre-set lower outer cylinder (1-3). The sealing pressure ring (2-11) is threadedly connected to the spare part at the lower part of the limiting step five (2-110), and a lower pressure ring (2-12) and a soluble plug are also connected below the sealing pressure ring (2-11).

9. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 8, characterized in that, The inner circle of the working cylinder slide (2-3) is machined with two sections of inner diameter, one smaller at the top and one larger at the bottom. The smaller inner diameter section is installed outside the first limiting step (103) of the inner cylinder (2-1), and the larger inner diameter section is installed outside the second limiting step (106). Both sections of the inner circle of the working cylinder slide (2-3) are precision machined surfaces. Under normal working conditions, the smaller inner diameter section of the working cylinder slide (2-3) blocks the backwash hole (2-101), and the larger inner diameter section is connected to the backwash control hole (2-104).

10. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 1, characterized in that, The cup (4-6) is installed inside the flow limiting device slide (4-3) and its lower part is located between the flow limiting device slide (4-3) and the upper push cylinder (4-7). The sealing surface of the outer circle of the central tube (4-2) is equipped with a seal. The staggered converging flow channel is composed of a main channel groove (4-10-1) machined in the center of the flow limiting plate (4-10) and an auxiliary channel groove (4-10-2) connected to the main channel groove (4-10-1). The limiting plate mounting groove (4-2-1) and the flow limiting plate (4-10) set on the outer wall of the central tube (4-2) are set in more than one set. The flow limiting plate (4-10) is welded in the limiting plate mounting groove (4-2-1).

11. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 10, characterized in that, The main channel groove (4-10-1) is a straight groove that runs through both ends of the flow limiting plate (4-10); the auxiliary channel grooves (4-10-2) are arranged on both sides of the main channel groove (4-10-1) and the flow channel shape is arc-shaped and downward sloping. The auxiliary channel grooves (4-10-2) arranged on both sides are staggered and connected end to end in the main channel groove (4-10-1).

12. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 11, characterized in that, Both the locking ring (4-4) and the flow limiting device locking ring (4-8) are broken rings with axial cuts. The axial cuts are either oblique cuts or vertical cuts with an angle between 1 degree and 89 degrees. The inner diameter of the locking ring (4-4) in its natural state is smaller than the outer diameter of the central pipe (4-2) segment. The outer circle of the flow limiting device locking ring (4-8) is machined with toothed threads and can cooperate with the toothed threads machined on the inner circle of the upper push cylinder (4-7).

13. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 12, characterized in that, The upper push cylinder (4-7) is a non-uniform diameter cylindrical body, with an upper cylinder (4-7-2) and a backstop thread (4-7-1) provided in the lower cylinder. The inner diameter of the upper cylinder (4-7-2) is smaller than the inner diameter of the lower cylinder. At least one sealing liquid passage groove (4-7-3) is provided on the outer wall of the upper cylinder (4-7-2), and the sealing liquid passage groove (4-7-3) is connected to the top of the upper cylinder (4-7-2). The inner circle of the lower cylinder of the upper push cylinder (4-7) is provided with a backstop thread (4-7-1), and the backstop thread (4-7-1) is a toothed thread that can cooperate with the toothed thread on the outer circle of the locking ring (4-8) of the flow limiting device.

14. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 13, characterized in that, The outer circle of the central tube (4-2) below the upper push cylinder limiting step (4-2-6) is machined with a continuation thread (4-2-7), which can be threaded to the washing and anti-spray mechanism.

15. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 14, characterized in that, The anti-spray mechanism for washing includes an upper outer cylinder (4-9) of a flow limiting device, a lower outer cylinder (4-11) of a flow limiting device, a lower push cylinder (4-12), a spring (4-13) of a flow limiting device, and a limiting cylinder (4-14). The two ends of the upper outer cylinder (4-9) of the flow limiting device are respectively connected to the connecting thread (4-2-7) in the central tube (4-2) and the lower outer cylinder (4-11) of the flow limiting device. The lower push cylinder (4-12) and the spring (4-13) of the flow limiting device are installed inside the lower outer cylinder (4-11) of the flow limiting device. The limiting cylinder (4-14) is installed below the spring (4-13) of the flow limiting device and is threadedly connected to the lower outer cylinder (4-11) of the flow limiting device. The limiting cylinder (4-14) is provided with at least one anti-spray liquid passage groove (4-14-1).

16. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 15, characterized in that, The inner circle of the lower outer cylinder (4-11) of the flow limiting device is a non-equal diameter inner circle and the internal threads at both ends are threadedly connected to the upper outer cylinder (4-9) and the limiting cylinder (4-14) of the flow limiting device, respectively; an inner conical mating surface (4-11-1) is provided between the two outer non-equal diameter inner circles of the lower outer cylinder (4-11) of the flow limiting device, and the inner conical mating surface (4-11-1) is a downward inclined surface.

17. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 16, characterized in that, The lower push cylinder (4-12) is a non-uniform diameter cylindrical body. The upper outer wall of the lower push cylinder (4-12) is an outer conical mating surface (4-12-1). This outer conical mating surface (4-12-1) is an upwardly inclined surface and can cooperate with the inner conical mating surface (4-11-1) in the lower outer cylinder (4-11) of the flow limiting device. At least one sealing ring groove is machined in the outer conical mating surface (4-12-1). The flow limiting device spring (4-13) is installed in the inner cavity below the spring limiting step (4-12-2) in the lower push cylinder (4-12).

18. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 17, characterized in that, The upper outer circle of the limiting cylinder (4-14) is provided with an external thread and can be threadedly connected to the lower outer cylinder (4-11) of the flow limiting device; the auxiliary washing and anti-spray liquid overflow groove (4-14-1) provided in the outer wall of the limiting cylinder (4-14) is an upper and lower through groove and at least one is provided; the upper outer cylinder (4-9) of the flow limiting device is a non-uniform diameter cylindrical body and the internal and external threads in the upper and lower ends of the cylinder can be threadedly connected to the continuation thread (4-2-7) of the central tube (4-2) and the lower outer cylinder (4-11) of the flow limiting device, respectively; the lower inner cavity of the upper outer cylinder (4-9) of the flow limiting device after being connected to the central tube (4-2) is connected to the limiting plate mounting groove (4-2-1).

19. A high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 18, characterized in that, The downhole annular flow limiting device (4) is connected to a centralizer (8) in the high-frequency injection and production tubing of the vertical well section on both sides of the downhole safety valve (6), and a flow section (7) is connected to the high-frequency injection and production tubing of the vertical well section on both sides of the downhole safety valve (6); the centralizer (8) and the downhole annular flow limiting device (4) are connected in series in the small-diameter tubing (3), and the downhole safety valve (6) and the flow section (7) are connected in series in the large-diameter tubing (5).

20. A high-frequency injection-production tubing string for a compressed air energy storage horizontal well as described in claim 19, characterized in that, The downhole gas-solid separator (10) is provided with an upper separator connector (10-1), an outer shell (10-2), a filter cartridge (10-3), a swirl vane (10-4), and a lower separator connector (10-5). The filter cartridge (10-3) with a centralizing plate (10-3-1) and the swirl vane (10-4) are respectively installed on the upper and lower parts of the outer shell (10-2). The upper end of the outer shell (10-2) is threaded to the upper separator connector (10-1) between the filter cartridge (10-3) and the upper separator connector (10-1) and a sealing ring is installed. The lower part of the outer shell (10-2) is threaded to the lower separator connector (10-5) and a sealing ring is installed, sealing the swirl vane (10-4) inside the outer shell (10-2).

21. The high-frequency injection-production tubing string for compressed air energy storage horizontal wells as described in claim 20, characterized in that, The upper inner cavity of the outer shell (10-2) is larger than the lower inner cavity, and a conical transition cavity is provided in the middle of the inner cavity. The filter cylinder (10-3) has holes or grooves in its cylinder. Two or more straightening plates (10-3-1) are provided and are located at the lower end of the filter cylinder (10-3). The outer diameter of the straightening plate (10-3-1) is equal to or greater than the maximum inner diameter of the conical transition cavity in the outer shell (10-2). The swirl plate (10-4) is a twisted plate structure. Its equivalent circle outer diameter after twisting, its pitch after twisting, and the thickness of the plate match the spiral groove machined in the lower inner cavity of the outer shell (10-2).

22. A well completion method applied to a high-frequency injection-production tubing string for a compressed air energy storage horizontal well according to any one of claims 1-21, characterized in that: Includes the following steps: A. Connect the pre-set working cylinder (1) in the downhole combined sealing device to the predetermined position in the completion string and lower it into the well for completion; B. Connect the sealing working cylinder (2) to the lower end of the injection and production string and lower it into the well. Press down the sealing working cylinder (2) through the injection and production string to achieve anchoring and sealing between the injection and production string and the completion string; C. Press down to seal the downhole annular flow limiting device (4) and test whether the injection and production string is leaking; D. If the pressure test shows no leakage in the injection and production string, start the downhole annular flow limiting device (4); E. After starting the downhole annular flow limiting device (4), continue to pressurize to perform backwashing and verify whether the downhole combined sealing device is working properly; F. After verifying that the downhole combined sealing device is working properly, inject casing protection fluid; G. Switch the well washing pipeline to the forward well washing process, let it stand for a period of time, and then pressurize the surface to remove the soluble plug in the downhole combined sealing device to achieve completion of the horizontal well high-frequency injection and production string.

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