Layered gas injection control system and control method

Abstract

The embodiment of the present application provides a layered gas injection control system and a control method, which comprises: a tubing inserted into an oil well, a plurality of packers connected to the tubing, and a plurality of adjustable gas distribution nozzles connected to the tubing; the plurality of adjustable gas distribution nozzles are distributed in different oil layers, and each adjustable gas distribution nozzle is clamped between two adjacent packers; the adjustable gas distribution nozzle comprises a plurality of nozzles arranged in an up-down manner, and a blocking ball used for blocking the nozzles; the adjustable gas distribution nozzle is further provided with a ball thrower used for pushing the blocking ball to move up and down; the tubing has a hollow lumen, and the nozzles are communicated with the lumen. The adjustable gas distribution nozzle of the technical scheme adopts a multi-nozzle design, the effective flow area can be adjusted by ball blocking, the gas suction capacity of each oil layer can be accurately matched, and thus precise quantitative differentiated gas distribution is realized.

Description

Technical Field

[0001] This invention relates to the field of oil extraction technology and systems for controlling gas flow, and particularly to a stratified gas injection control system and a stratified gas injection control method. Background Technology

[0002] In the field of oil extraction, gas injection technology is a key means of developing difficult-to-access reserves such as low-permeability and extra-heavy oils. This is especially true for continental sedimentary reservoirs in my country, which have complex geological conditions and are generally characterized by strong inter-layer heterogeneity, numerous oil layers, large vertical span, and significant differences in inter-layer physical properties. Under the general gas injection development model, the injected fluid tends to preferentially enter high-permeability layers, leading to severe gas channeling. Medium and low-permeability layers are difficult to effectively drive, and a large amount of residual oil remains underground, which seriously restricts the improvement of reservoir recovery.

[0003] Compared to conventional water injection development, stratified gas injection, especially development using air as the injection medium, faces far more severe challenges. Air has low density, low viscosity, and strong oxidizing properties, and poses a high safety risk, placing extremely stringent requirements on the performance and processes of downhole injection equipment. As the core flow control component of stratified gas injection technology, the gas distribution device directly determines the accuracy of gas distribution across each layer and the stability of the injection process. However, traditional gas distribution devices and related technologies have significant problems: traditional gas distribution devices mostly use valve regulation, resulting in low gas distribution accuracy and difficulty in achieving quantitative differentiated gas distribution based on the gas absorption capacity of different formations. This leads to uneven displacement across layers, failing to fully utilize the remaining oil in low- and medium-permeability layers, and affecting the overall development effect. Therefore, how to achieve a precise and flexible stratified gas injection control system is a problem that needs to be solved. Summary of the Invention

[0004] This invention provides a stratified gas injection control system and method, which achieves precise quantitative differentiated gas distribution by setting an adjustable gas nozzle with multiple nozzles and adjusting the effective flow area of ​​the adjustable gas nozzle by ball-throwing and blocking.

[0005] To achieve the above objectives, in one aspect, embodiments of the present invention provide a stratified gas injection control system (or stratified gas injection string), comprising: tubing extending into an oil well, multiple packers connected to the tubing, and multiple adjustable gas nozzles connected to the tubing; the multiple adjustable gas nozzles are distributed vertically in different oil layers, and each adjustable gas nozzle is disposed between two adjacent packers; the adjustable gas nozzle includes multiple nozzles arranged vertically, and a plugging ball for sealing the nozzles; the tubing has a hollow cavity, and the nozzles communicate with the cavity.

[0006] Furthermore, the adjustable air nozzle also includes a ball carrier and a ball launcher; the ball carrier is provided with an annular ball carrier groove; there are one or more blocking balls; a spring is also provided in the ball carrier groove to compress the blocking balls; a push rod is provided at the lower end of the ball launcher, and the ball carrier includes an axially opened limiting groove, the push rod can move along the limiting groove, and the limiting groove intersects with the ball carrier groove.

[0007] Furthermore, a ball-receiving groove is provided on the outer surface of the push rod.

[0008] Furthermore, the stratified air injection control system also includes a ball launcher push ring, the outer wall of which is movably connected to the inner side of the adjustable air nozzle by a thread; the bottom of the ball launcher push ring is provided with an annular groove, and the top of the ball launcher is provided with a locking block, which is located in the groove.

[0009] Furthermore, the ball-throwing device's push ring also has a plug-in hole for connecting the adjustment equipment; the outer diameter of the adjustment equipment is smaller than the inner diameter of the tube.

[0010] Furthermore, the packers are connected to each other via pressure transmission lines.

[0011] Furthermore, the packer includes a first packer and a second packer; the first packer includes a main inlet pipe, which has a radial blind hole, a first axial passage, and a radial through hole connecting the cavity. One end of the first axial passage is connected to the hydraulic cavity of the rubber sleeve, and the other end of the first axial passage is connected to the inner end of the radial blind hole; a pressure-holding sleeve that can move axially is also fitted on the outside of the main inlet pipe, and a connecting groove that can simultaneously connect the radial blind hole and the radial through hole is formed on the inner side of the pressure-holding sleeve. The axial width of the connecting groove is greater than the distance between the radial blind hole and the radial through hole; the upper and lower ends of the connecting groove have an upper end face and a lower end face, respectively, and the area of ​​the upper end face is different from the area of ​​the lower end face.

[0012] Furthermore, one end of the rubber sleeve is provided with an end pipe passage, which is connected to the hydraulic cavity of the rubber sleeve; the first packer also includes a pressure relief sleeve for relieving pressure in the hydraulic cavity of the rubber sleeve, and a pressure relief inner liner is screwed to the inner side of the pressure relief sleeve to allow it to move up and down; a pressure relief outer sleeve is also fitted on the outer side of the pressure relief sleeve, and a pressure relief hole communicating with the outside is opened on the side wall of the pressure relief outer sleeve. When the pressure relief sleeve is at its extreme position close to the fixed end pipe of the first rubber sleeve, the bottom end of the pressure relief sleeve blocks the end pipe passage; when the pressure relief sleeve is away from the fixed end pipe of the first rubber sleeve, the pressure relief hole communicates with the end pipe passage.

[0013] Furthermore, a second axial passage is provided in the side wall of the liquid inlet main pipe, and a venting groove communicating with the second axial passage is provided in the inner side wall of the liquid inlet main pipe; an emergency pressure relief sleeve for venting the hydraulic cavity of the rubber sleeve is also sleeved inside the liquid inlet main pipe, and the emergency pressure relief sleeve can move up and down to open or block the passage between the venting groove and the cavity.

[0014] On the other hand, embodiments of the present invention also provide a layered gas injection control method, comprising: extending an oil pipe into a predetermined position in an oil well; setting a packer in the oil well by injecting pressurized liquid; determining the required flow rate for each adjustable gas nozzle located in different oil layers, and then determining the nozzle to be plugged in the adjustable gas nozzle according to the required flow rate, and then completing the plugging operation of the nozzle to be plugged by a ball launcher and a plugging ball; and performing gas injection operations on different oil layers through each adjustable gas nozzle.

[0015] In addition, embodiments of the present invention also provide an adjustable air nozzle for stratified air injection, the adjustable air nozzle comprising a plurality of nozzles arranged vertically and vertically, and a plugging ball for sealing the nozzles.

[0016] Furthermore, the adjustable air nozzle also includes a ball carrier and a ball launcher. The ball carrier is provided with an annular ball carrier groove; there are one or more blocking balls; a spring is also provided in the ball carrier groove to compress the blocking balls; a push rod is provided at the lower end of the ball launcher; the ball carrier includes an axially opened limiting groove, the push rod can move along the limiting groove, and the limiting groove intersects with the ball carrier groove.

[0017] Furthermore, in the adjustable valve, a ball-receiving groove is also provided on the outer surface of the push rod.

[0018] Furthermore, the adjustable air nozzle also includes a ball-throwing device push ring, the outer wall of which is movably connected to the inner side of the adjustable air nozzle by means of threads; the bottom of the ball-throwing device push ring is provided with an annular groove, and the top of the ball-throwing device is provided with a locking block, which is located in the groove.

[0019] The above technical solution has the following beneficial effects:

[0020] This technical solution no longer uses valves to regulate the flow rate of the gas distribution device as in existing technologies. Instead, each adjustable gas distribution nozzle is designed as a multi-nozzle device. When applied to different oil layers, the required flow rate is determined according to actual needs, and then the number of nozzles that the adjustable gas distribution nozzle needs to block is determined. The blocking operation can then be completed by throwing a ball, thereby adjusting the effective flow area of ​​the adjustable gas distribution nozzle, accurately matching the gas intake capacity of each oil layer, and achieving precise quantitative differentiated gas distribution.

[0021] In addition, this technical solution also has the following characteristics:

[0022] 1) All packers utilize prestressed expansion gas-tight packers. Multiple packers form a unified pressure system through pressure transmission lines, allowing for simultaneous setting with a single pressurization. This avoids the pressure unevenness and tubing deformation problems caused by conventional step-by-step setting, while effectively improving operational efficiency. Furthermore, the first packer automatically cuts off the hydraulic passage when its internal expansion pressure reaches 26MPa. After setting, it locks in place, ensuring reliable sealing. The internal pressure of the packer remains constant, unaffected by production pressure differential fluctuations, achieving long-term automatic pressure maintenance. Correspondingly, multiple second packers also simultaneously achieve automatic pressure maintenance.

[0023] 2) It can adopt a dual design of rotary unsealing and ball-drop hydraulic unsealing, combined with a synchronous unsealing mechanism, which makes the unsealing operation simple, avoids well jamming accidents, ensures the safe recovery of downhole tools, and reduces well workover risks and costs. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the overall structure of a layered gas injection control system according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the adjustable air nozzle in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram showing the connection between the ball launcher and the ball carrier in the adjustable air nozzle;

[0028] Figure 4 This is a diagram illustrating how the ball-slinging device moves the blocking ball.

[0029] Figure 5 This is a schematic diagram of the ball-throwing machine;

[0030] Figure 6 This is a schematic diagram of the structure of the first packer in an embodiment of the present invention;

[0031] Figure 7 yes Figure 6 A magnified view of a section at point A in the middle;

[0032] Figure 8 yes Figure 7 A schematic diagram showing the movement of the central pressure sliding sleeve;

[0033] Figure 9 yes Figure 6 A magnified view of a section at point B in the middle;

[0034] Figure 10 yes Figure 9 A schematic diagram showing the movement of the pressure relief sleeve.

[0035] Figure 11 yes Figure 6 A magnified view of a section at point C;

[0036] Figure 12 yes Figure 11 A schematic diagram of the emergency pressure relief sleeve after it has been moved;

[0037] Figure 13 This is a schematic diagram of the external shape of the testing device in an embodiment of the present invention;

[0038] Figure 14 This is a photograph of the ZQK342-110 packer in a specific embodiment of the present invention;

[0039] Figure 15 The above is a photograph of the ZJZQK342-110 packer in a specific embodiment of the present invention.

[0040] Figure 16 This is a photograph of the adjustable air nozzle in a specific embodiment of the present invention;

[0041] Figure 17 These are actual photographs of the tubing anchors used in specific embodiments of the present invention;

[0042] Figure 18 These are photographs of the actual testing equipment in a specific embodiment of the present invention.

[0043] Icon labels:

[0044] 1. First packer;

[0045] 101. Upper end pipe; 102. Pressure relief inner liner pipe; 103. Pressure relief outer sleeve pipe; 1031. Pressure relief hole; 104. Pressure relief sliding sleeve; 1041. Second sealing ring; 105. First rubber sleeve fixed end pipe; 1051. End pipe passage; 106. Rubber sleeve inner liner pipe; 107. Rubber sleeve; 1071. Rubber sleeve hydraulic chamber; 108. Second rubber sleeve fixed end pipe;

[0046] 109. Pressure-holding sleeve; 1091. Communicating groove; 1092. Upper end face; 1093. Lower end face; 1094. First sealing ring;

[0047] 110. Main inlet pipe; 1101. Radial through hole; 1102. Radial blind hole; 1103. First axial passage; 1104. Second axial passage; 1105. Connecting passage; 1106. Drainage channel;

[0048] 111. First packer connector; 113. Emergency pressure relief sleeve; 1131. Third sealing ring;

[0049] 2. Second packer; 21. Second packer connector;

[0050] 3. Adjustable air nozzle; 31. Ball thrower push ring; 311. Plug-in hole; 312. Slot; 32. Adjustable air nozzle main pipe; 33. Ball thrower; 331. Locking block; 332. Push rod; 3321. Ball receiving slot;

[0051] 34. Ball carrier; 341. Ball carrier ring groove; 342. Spring; 343. Limiting groove; 35. Blocking ball; 36. Nozzle assembly; 361. Nozzle; 37. Nozzle assembly inner liner;

[0052] 4. Tubing anchor; 5. Tubing; 51. Lumen; 6. Pressure transmission line; 7. Adjustment equipment; 71. Fin;

[0053] 8. Unsealing ball; 9. Oil layer; 10. Oil well. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] like Figure 1 , Figure 2 As shown, this embodiment of the invention provides a layered gas injection control system, including: an oil pipe 5 extending into an oil well 10, multiple packers connected to the oil pipe 5, and multiple adjustable gas nozzles 3 connected to the oil pipe 5; the multiple adjustable gas nozzles 3 are distributed vertically in different oil layers 9, and each adjustable gas nozzle 3 is disposed between two adjacent packers; the adjustable gas nozzle 3 includes multiple vertically arranged nozzles 361 and a plugging ball 35 for plugging the nozzles 361; the adjustable gas nozzle 3 is also provided with a ball launcher 33 for pushing the plugging ball 35 up and down; the oil pipe 5 has a hollow cavity 51, and the nozzles 361 are connected to the cavity 51.

[0056] To address the aforementioned problems, in this embodiment of the invention, instead of using valves to regulate the flow rate of the gas distribution device as in the prior art, the gas distribution device is configured as an adjustable gas nozzle 3, such as... Figure 2As shown, multiple holes arranged vertically are opened on the tubular nozzle assembly 36, and a nozzle 361 of equal diameter (e.g., φ2) is installed in each hole. When the oil layer 9 where the adjustable air nozzle 3 is located requires a large gas flow rate, all nozzles 361 can be kept open. When the oil layer 9 requires a small gas flow rate, the corresponding nozzle 361 can be blocked by a ball-throwing operation with a blocking ball 35, thereby reducing the number of available nozzles 361 and thus reducing the effective flow area of ​​the adjustable air nozzle 3. Therefore, by blocking different numbers of nozzles 361, the flow rate of the adjustable air nozzle 3 can be adjusted step by step, accurately matching the gas intake capacity of each oil layer 9, and achieving precise quantitative differential gas distribution.

[0057] During the setting stage, by introducing hydraulic medium (such as water) into the lumen 51, the packer can be expanded and locked against the sidewall of the well 10 to achieve the fixation of the stratified gas injection control system; during the gas injection stage, by introducing special medium into the lumen 51, gas with a set pressure is generated after reaction, and the gas will be sprayed outward from the open nozzle 361 into the oil layer 9.

[0058] The tubing 5 is not necessarily a single, continuous pipe from top to bottom; it can also be composed of multiple pipes connected together. For example, some pipe sections can be distributed within the adjustable nozzle 3 or the packer, and all pipe sections can be connected together to form the integral tubing 5.

[0059] Furthermore, the specific method for adjusting the effective flow area of ​​the adjustable air nozzle 3 by means of a ball-throwing motion is as follows: Figure 2 , Figure 3 , Figure 4As shown: The adjustable air nozzle 3 also includes a fixedly installed ball carrier 34, which has an annular ball carrier groove 341. There are one or more blocking balls 35. When there are multiple blocking balls 35, they are arranged in the ball carrier groove 341 (an annular cover plate is fitted on the outside of the ball carrier groove 341, and the groove depth and width of the ball carrier groove 341 are only slightly larger than the diameter of the blocking balls 35, thus ensuring that the multiple blocking balls 35 are arranged in an orderly annular pattern), and all the blocking balls 35 are squeezed together by a spring 342. A push rod 332 is provided at the lower end of the ball launcher 33. The ball carrier 34 includes an axially opened limiting groove 343, and the width of the limiting groove 343 is greater than that of one blocking ball 35 and less than the sum of the diameters of two blocking balls 35. When the ball launcher 33 moves downwards under control, the push rod 332 moves downwards along the limiting groove 343. Simultaneously, the ball-carrying ring groove 341 is positioned perpendicular to the axial direction, and the limiting groove 343 intersects the ball-carrying ring groove 341 perpendicularly. Therefore, after the push rod 332 enters the ball-carrying ring groove 341, it pushes a blocking ball 35 (which was originally located at the intersection of the limiting groove 343 and the ball-carrying ring groove 341) downwards out of the ball carrier 34 and continues to move. During this movement, because the nozzle assembly 36 is also fitted with a nozzle assembly liner 37, the cavity between the two forms a movement path for the push rod 332, so the blocking ball 35 will not move radially. When the blocking ball 35 approaches a nozzle 361 to be blocked, under the push of the gas, the blocking ball 35 automatically enters the inlet of the nozzle 361, blocking the nozzle 361.

[0060] Furthermore, to make the blocking ball 35 more stable during movement, an opening can be made on the outer surface of the pusher 332. Figure 5 The ball-holding groove 3321 shown has an open top surface and two open sides (although the left and right sides of the ball-holding groove 3321 are also open, the pressure on both sides is balanced under the action of pressurized gas, so even if the blocking ball 35 moves outside the limiting groove 343, it can maintain balance and will not move circumferentially). The thickness of the lower end is less than that of the upper end. Before the ball-throwing operation, the ball-throwing device 33 is in the uppermost extreme position. At this time, the lower part of the ball-holding groove 3321 occupies the position where the limiting groove 343 and the ball-carrying ring groove 341 intersect. Therefore, the blocking ball 35 in the ball-carrying ring groove 341 will not enter the limiting groove 343. When the ball-holding groove 3321 moves to the position of the ball-carrying ring groove 341, the blocking ball 35 will enter the ball-holding groove 3321 under the push of the spring 342.

[0061] Furthermore, in order to enable the ball-throwing device 33 to move in a controlled manner, such as Figure 2 , Figure 3As shown, the layered air injection control system also includes a ball-slinger push ring 31. The outer wall of the ball-slinger push ring 31 has an external thread, and the inner side of the adjustable air nozzle main pipe 32 has a corresponding internal thread. When the ball-slinger push ring 31 is rotated, the ball-slinger push ring 31 will move up and down because the adjustable air nozzle main pipe 32 is fixed. At the same time, the bottom of the ball-slinger push ring 31 has an annular groove 312, and the top of the ball-slinger 33 has a locking block 331. The locking block 331 is engaged in the groove 312, that is, the ball-slinger 33 can rotate relative to the ball-slinger push ring 31. Therefore, under the drive of the ball-slinger push ring 31, the ball-slinger 33 can move up and down.

[0062] Furthermore, it is obviously difficult to directly and manually rotate the ball-throwing device to push the ring 31 outside the oil well 10. In order to achieve the ball-throwing operation, it can be equipped with... Figure 13 The adjustment device 7 shown can extend into the lumen 51. An additional [feature / feature] is also provided on the ball-throwing device push ring 31. Figure 3 As shown in the insertion hole 311, after the adjustment device 7 is extended to the predetermined height position, its fins 71 are unfolded and inserted into the insertion hole 311. Then, by rotating the fins 71, the ball throwing operation can be realized. In practical applications, the adjustment device 7 can be equipped with structures such as motors and screws to achieve automated operation. At the same time, it can also be equipped with magnetic positioning instruments, control modules, anti-collision devices, etc., to better meet the usage requirements. Among them, the control module can integrate temperature sensors and pressure sensors for accurate testing of the temperature and pressure of each layer. The gas injection volume can be accurately calculated, and it can also be connected to a PLT gas meter to directly read various parameters.

[0063] Furthermore, in addition to improvements to the traditional gas distribution device, this embodiment of the invention also improves the packers of existing technologies to solve the problems of uneven pressure and tubing deformation caused by the step-by-step setting of existing packers, and effectively improves operational efficiency. Therefore, in this technical solution, all packers expand and de-seal simultaneously. The advantage of simultaneous packer de-sealment is that it avoids well jamming accidents caused by step-by-step de-sealment. To achieve simultaneous de-sealment, the expansion fluid of all packers must be in the same pressure system. Therefore, as... Figure 1 As shown, multiple packers are connected in series through pressure transmission line 6 (outer diameter 4mm). Since they are in the same pressure system, synchronous setting and unsealing can be achieved, thus improving operational efficiency.

[0064] In addition, in order to achieve the automatic pressure holding function described later, the packer is divided into two types: one is a first packer 1 with automatic pressure holding function (preferably set at the position closest to the wellhead, which can also be called the top packer), and the other is a second packer 2 with a structure that is basically the same as that of a conventional packer. One first packer 1 is set, and multiple second packers 2 can be set (this technical solution can achieve effective separation of 6 layers or more), and the number is determined according to actual needs. The first packer 1 is provided with a first packer connector 111, and the second packer 2 is provided with a second packer connector 21. During setting, the hydraulic medium in the lumen 51 enters the first packer 1 and then exits from the first packer connector 111, and enters the second packer 2 located in the second layer through the second packer connector 21, thereby realizing series connection. If there are other second packers 2 below, the bottom of the second packer 2 in the second layer is connected to another second packer connector 21, through which hydraulic medium is supplied to the second packer 2 in the third layer, and so on, until all packers are connected in series for synchronous operation.

[0065] Furthermore, this technical solution improves upon conventional packers. Conventional packers are equipped with expandable rubber sleeves that expand when hydraulic medium is introduced into them, thereby clamping the outer wall onto the inner wall of the well 10 and securing the entire stratified gas injection control system. In addition to this basic function, the first packer 1 in this technical solution can automatically cut off the fluid inlet passage under specific pressure, thus achieving automatic pressure maintenance.

[0066] The structure of the first packer 1 is as follows: Figure 6 , Figure 7 As shown:

[0067] The first packer 1 includes a liquid inlet main pipe 110, which has a radial through hole 1101, a radial blind hole 1102, and a first axial passage 1103. The radial through hole 1101 penetrates the side wall of the liquid inlet main pipe 110. One end of the first axial passage 1103 is connected to the hydraulic chamber 1071 of the rubber sleeve, and the other end of the first axial passage 1103 is connected to the inner end of the radial blind hole 1102. A pressure-holding sleeve 109 that can move axially is also fitted on the outside of the liquid inlet main pipe 110. An annular connecting groove 1091 is formed on the inner side of the pressure-holding sleeve 109, and the axial width of the connecting groove 1091 is greater than the distance between the radial blind hole 1102 and the radial through hole 1101. That is, at the beginning of the setting stage, the hydraulic medium in the cavity 51 enters the connecting groove 1091 through the radial through hole 1101, and then enters the first axial passage 1103 through the radial blind hole 1102. The hydraulic medium entering the first axial passage 1103 flows into the rubber sleeve hydraulic chamber 1071 (located between the outside of the rubber sleeve liner tube 106 and the inside of the rubber sleeve 107). The upper and lower ends of the rubber sleeve 107 are fixed by the first rubber sleeve fixed end tube 105 and the second rubber sleeve fixed end tube 108, respectively. Therefore, the hydraulic medium causes the middle part of the rubber sleeve 107 to expand under pressure and form a waist drum shape, thereby making the expanded rubber sleeve 107 clamped on the side wall of the oil well 10. At the same time, the hydraulic medium also flows into all the second packers 2 below, causing the rubber sleeves of the second packers 2 to expand synchronously and achieve setting.

[0068] To achieve automatic pressure holding, such as Figure 7 As shown, the connecting groove 1091 has an upper end face 1092 and a lower end face 1093 at its upper and lower ends, respectively. The area of ​​the upper end face 1092 is different from the area of ​​the lower end face 1093. During the setting process, the liquid medium in the connecting groove 1091 will exert pressure on the two end faces. Due to the difference in area, the forces acting on the two end faces are naturally different, for example... Figure 7 In the middle section, the lower end face 1093 has a larger groove width and area, thus experiencing greater force. When the pressure of the liquid medium in the connecting groove 1091 reaches a preset value, the pressure difference between the two end faces also reaches a threshold, causing the pressure-holding sleeve 109 to slide downwards until it reaches a limited position (achieved through a limiting device, etc.). At this point, the state is as follows: Figure 8As shown, the movement of the pressure-holding sleeve 109 prevents the connecting groove 1091 from simultaneously connecting the radial through hole 1101 and the radial blind hole 1102. The presence of the first sealing ring 1094 ensures that the liquid medium will not enter the radial blind hole 1102 through the gap between the pressure-holding sleeve 109 and the liquid inlet main pipe 110. At this time, the liquid inlet passage is closed, and the hydraulic medium in the pipe cavity 51 can no longer enter the rubber sleeve hydraulic chamber 1071 and the second packer 2 through the radial through hole 1101. Correspondingly, even if the pressure in the pipe cavity 51 is released, the hydraulic medium in the first packer 1 and the second packer 2 will not return to the pipe cavity 51. This achieves the pressure holding of the first packer 1 and the second packer 2. Only after taking appropriate joint measures will all the packers connected in series be unsealed at the same time. Only then can the stratified gas injection control system be removed from the oil well 10. The simultaneous unsealing method can effectively avoid the well jamming accident that is easily caused by the step-by-step unsealing in the prior art.

[0069] Furthermore, in order to achieve unsealing, this technical solution sets up two methods: rotational unsealing and ball-throwing hydraulic unsealing, where rotational unsealing can be used as the standard operating method, and ball-throwing hydraulic unsealing is used as an emergency treatment method.

[0070] To achieve rotational unsealing, this technical solution incorporates the following design:

[0071] One end of the rubber sleeve 107 is connected to a first rubber sleeve fixed end tube 105. The first rubber sleeve fixed end tube 105 has an end tube passage 1051, and the end tube passage 1051 is connected to the rubber sleeve hydraulic chamber 1071. The first packer 1 also includes a pressure relief sleeve 104 that can move axially. A pressure relief inner liner 102 is screwed to the inner side of the pressure relief sleeve 104. A pressure relief outer sleeve 103 is also sleeved on the outer side of the pressure relief sleeve 104. A pressure relief hole 1031 communicating with the outside is opened on the side wall of the pressure relief outer sleeve 103.

[0072] like Figure 9 As shown, when the pressure relief sleeve 104 is at its limit position near the fixed end pipe 105 of the first rubber sleeve, the bottom end of the pressure relief sleeve 104 blocks the end pipe passage 1051, and a second sealing ring 1041 for preventing leakage is provided on the outer side of the pressure relief sleeve 104. At this time, the hydraulic medium in the end pipe passage 1051 is in a closed state and cannot be discharged from the pressure relief hole 1031. When the operator rotates the upper end pipe 101, the pressure relief inner liner 102 connected to the upper end pipe 101 will rotate synchronously. The rotation of the pressure relief inner liner 102 allows the pressure relief sleeve 104 to move upward (the pressure relief sleeve 104 has a limit to ensure that it only moves axially and does not rotate). When the bottom end of the pressure relief sleeve 104 moves away from the outlet of the end pipe passage 1051, as... Figure 10As shown, the end pipe passage 1051 is connected to the pressure relief hole 1031, and the hydraulic medium in all packers is discharged along the pressure relief hole 1031 into the oil well 10 outside the stratified gas injection control system. After the pressure is lost, the first packer 1 and the second packer 2 are reset, realizing synchronous unsealing.

[0073] If the above-mentioned rotational unsealing fails due to unforeseen circumstances, hydraulic ball-throwing unsealing can be used as an emergency measure. To achieve hydraulic ball-throwing unsealing, this technical solution is designed as follows:

[0074] A second axial passage 1104 is also provided in the side wall of the liquid inlet main pipe 110, and a venting groove 1106 communicating with the second axial passage 1104 is also provided in the inner side wall of the liquid inlet main pipe 110 (the venting groove 1106 is also connected to the connector communication passage 1105 so as to transport the liquid medium to the second packer 2 through the first packer connector 111); an emergency pressure relief sleeve 113 is also sleeved on the inner side of the liquid inlet main pipe 110, and the emergency pressure relief sleeve 113 can move up and down to open or block the passage between the venting groove 1106 and the pipe cavity 51.

[0075] like Figure 11 As shown, when the emergency pressure relief sleeve 113 is in its initial upper position, its top end face is pressed against the limiting groove opened on the liquid inlet main pipe 110. At this time, the emergency pressure relief sleeve 113 separates the relief groove 1106 from the pipe cavity 51, and due to the presence of the third sealing ring 1131, the hydraulic medium in the relief groove 1106 will not leak into the pipe cavity 51 along the gap. When using ball-throwing hydraulic unsealing, first, the unsealing ball 8 is thrown into the oil pipe 5, so that the unsealing ball 8 is pressed against the upper end face of the emergency pressure relief sleeve 113. Then, hydraulic pressure is applied to the pipe cavity 51 to push the unsealing ball 8 downward, thereby driving the emergency pressure relief sleeve 113 downward. When the emergency pressure relief sleeve 113 moves to the upper end face of the pipe cavity 51, the unsealing ball 8 is pushed downward, thereby driving the emergency pressure relief sleeve 113 downward. Figure 12 In the indicated position, the vent 1106 is no longer obstructed by the emergency pressure relief sleeve 113, thus achieving communication between the vent 1106 and the cavity 51, as shown. Figure 12 As shown by the hollow arrow, the hydraulic medium in the relief tank 1106 flows back into the cavity 51 (after the emergency relief sleeve 113 moves into place, the hydraulic pressure pushing the unsealing ball 8 is removed, so the pressure inside the cavity 51 is much less than the pressure inside the packer), so that all packers are released from pressure and synchronous unsealing is achieved.

[0076] To secure the downhole portion of the stratified gas injection string and ensure it does not creep and maintains a long-term seal, a tubing anchor 4 can be installed at the bottom of the packer. Additionally, components such as a tubing setting spring eliminator can also be installed.

[0077] In addition, this embodiment of the invention also provides an adjustable air nozzle 3 for layered air injection. The adjustable air nozzle 3 includes a plurality of nozzles 361 arranged vertically and vertically, and a blocking ball 35 for blocking the nozzles 361.

[0078] Furthermore, the adjustable air nozzle 3 also includes a ball carrier 34 and a ball launcher 33. The ball carrier 34 is provided with an annular ball carrier groove 341; there are one or more blocking balls 35; a spring 342 for squeezing the blocking balls 35 is also provided in the ball carrier groove 341; a push rod 332 is provided at the lower end of the ball launcher 33; the ball carrier 34 includes an axially opened limiting groove 343, the push rod 332 can move along the limiting groove 343, and the limiting groove 343 intersects with the ball carrier groove 341.

[0079] Furthermore, a ball-receiving groove 3321 is provided on the outer surface of the push rod 332.

[0080] Furthermore, the adjustable air nozzle 3 also includes a ball-throwing device push ring 31, the outer wall of which is movably connected to the inner side of the adjustable air nozzle 3 by means of threads; the bottom of the ball-throwing device push ring 31 is provided with an annular groove 312, and the top of the ball-throwing device 33 is provided with a locking block 331, and the locking block 331 is located in the groove 312.

[0081] This invention also provides a stratified gas injection control method, which employs the aforementioned stratified gas injection control system, comprising:

[0082] S101. Insert the tubing into the predetermined position in the oil well;

[0083] S102. The packer is set in the oil well by injecting pressurized fluid;

[0084] S103. For each adjustable air nozzle located in different oil layers, first determine the required flow rate, then determine the nozzle to be blocked in the adjustable air nozzle according to the required flow rate, and then complete the blocking operation of the nozzle to be blocked by the ball thrower and the blocking ball.

[0085] S104. Gas injection is performed on different oil layers through various adjustable gas nozzles.

[0086] In one specific embodiment, the adjustable air nozzle 3 is made of 17-4PH material, with a temperature resistance of 250℃ and a pressure resistance of 60MPa; the packers (including the first packer ZQK342-110 and the second packer ZJZQK342-110) are made of 17-4PH steel, with a temperature resistance of 250℃ and a pressure resistance of 60MPa, and are also resistant to carbon dioxide and hydrogen sulfide, as well as oxygen corrosion; the tubing anchor 4 is made of 42CrMo, with a temperature resistance of 250℃ and a pressure resistance of 60MPa; and the adjustment device 7 is made of 17-4PH material, with a temperature resistance of 120℃ and a pressure resistance of 45MPa.

[0087] The ZQK342-110 packer features: rotational unsealing without pressure relief, reliable setting without rebound; an added release system ensures reliable unsealing, and dual unsealing methods prevent well jamming; the 107 rubber sleeve is made of fluororubber, with a temperature resistance of 250℃, a pressure resistance of 60MPa, and resistance to oxygen corrosion; it employs both metal sealing and rubber ring sealing, a composite method for greater reliability.

[0088] The ZJZQK342-110 packer is used to separate oil layers. Its features include: it can achieve the function of setting two or more layers at the same time, with reliable setting; it can be used in multiple layers, achieving effective separation of 6 layers or more; it can achieve the function of setting and unsetting simultaneously with the ZQK342-110 packer, making it less prone to well sticking.

[0089] The orifice diameter of nozzle 361 is set to φ2mm. The gas injection volume can be precisely controlled by the ball dropping operation. The nozzle 361 is coated with ceramic lining, which can withstand the erosion of high pressure gas and can be operated repeatedly. When the adjustable gas nozzle 3 is lowered into the well, it is arranged between two packers to achieve replacement without dead zone and achieve the purpose of safe gas injection.

[0090] In this specific embodiment, the sealing pressure is 26 MPa. At this pressure, the first packer automatically maintains pressure, thereby enabling all packers connected in series to maintain pressure. This function allows the packers to be unaffected by external pressure and avoids interlayer interference. In conventional packers, the packer will contract and unseal when the pressure in the lumen 51 decreases.

[0091] The operation flow of this specific embodiment is as follows:

[0092] 1) Preparations before running into the well: Perform full well cleaning and scraping of oil well 10, and scrape at least 3 times within a range of ±20 meters from the packer insertion position;

[0093] 2) The tubing should be lowered at a uniform speed and smoothly;

[0094] 3) After the data is verified to be correct after the insertion, first set the tubing anchor 4. The setting is considered qualified when the load is reduced to 0.

[0095] 4) Pressurize the oil pipe 5 to set the packers, stabilize the pressure at 5MPa, 10MPa and 15MPa for 5 minutes each, and then pressurize until each packer is set.

[0096] 5) After the packer is set, a sealing test is performed;

[0097] 6) Remove the well repair machine after the sealing is completed;

[0098] 7) Perform ball-throwing (blocking ball 35) operation according to the requirements of each oil layer to adjust each adjustable air nozzle 3;

[0099] 8) The adjustment and testing equipment 7 can be connected to the gas meter to measure the gas distribution of each layer and make corrections and adjustments until the requirements are met.

[0100] 9) When it is necessary to dismantle the equipment, the packer can be unsealed by the aforementioned rotational unsealing (achieved by rotating the upper tube 101) or by ball-throwing hydraulic unsealing (achieved by dropping the unsealing ball 8 and applying pressure):

[0101] In the above detailed description, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features of the single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, wherein each claim stands alone as a preferred embodiment of the invention.

[0102] The disclosed embodiments have been described above to enable any person skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit and scope of this disclosure. Therefore, this disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0103] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A stratified gas injection control system, characterized in that, include: The oil pipe (5) extends into the oil well (10), a plurality of packers connected to the oil pipe (5), and a plurality of adjustable air nozzles (3) connected to the oil pipe (5); the plurality of adjustable air nozzles (3) are distributed vertically in different oil layers (9), and each adjustable air nozzle (3) is located between two adjacent packers. The adjustable nozzle (3) includes a plurality of nozzles (361) arranged vertically, and a plugging ball (35) for sealing the nozzles (361). The oil pipe (5) has a hollow cavity (51) inside, and the nozzle (361) is connected to the cavity (51).

2. The stratified gas injection control system as described in claim 1, characterized in that, The adjustable air nozzle (3) also includes a ball carrier (34) and a ball thrower (33). The ball carrier (34) is provided with an annular ball carrier groove (341). There are one or more blocking balls (35). A spring (342) for squeezing the blocking balls (35) is also provided in the ball carrier groove (341). The ball thrower (33) is provided with a push rod (332) at its lower end. The ball carrier (34) includes an axially opened limiting groove (343). The push rod (332) can move along the limiting groove (343), and the limiting groove (343) intersects with the ball carrier ring groove (341).

3. The stratified gas injection control system as described in claim 2, characterized in that, The push rod (332) has a ball groove (3321) on its outer surface.

4. The stratified gas injection control system as described in claim 2, characterized in that, It also includes a ball-throwing device push ring (31), the outer wall of which is movably connected to the inner side of the adjustable air nozzle (3) by a thread; the bottom of the ball-throwing device push ring (31) is provided with an annular groove (312), the top of the ball-throwing device (33) is provided with a locking block (331), and the locking block (331) is located in the groove (312).

5. The stratified gas injection control system as described in claim 3, characterized in that, The ball thrower push ring (31) is also provided with a plug hole (311) for connecting the adjustment device (7); the outer diameter of the adjustment device (7) is smaller than the inner diameter of the cavity (51).

6. The stratified gas injection control system as described in claim 1, characterized in that, Each of the packers is connected in series via a pressure transmission line (6).

7. The stratified gas injection control system as described in claim 6, characterized in that, The packer includes a first packer (1) and a second packer (2); the first packer (1) includes a liquid inlet main pipe (110), the liquid inlet main pipe (110) is provided with a radial blind hole (1102), a first axial passage (1103), and a radial through hole (1101) connecting the cavity (51), one end of the first axial passage (1103) is connected to the hydraulic cavity (1071) of the rubber sleeve, and the other end of the first axial passage (1103) is connected to the inner end of the radial blind hole (1102); the outer side of the liquid inlet main pipe (110) is also provided with a pressure holding sleeve (109) that can move axially, and the inner side of the pressure holding sleeve (109) is provided with a connecting groove (1091) that can simultaneously connect the radial blind hole (1102) and the radial through hole (1101).

8. The stratified gas injection control system as described in claim 7, characterized in that, One end of the rubber sleeve (107) is provided with an end pipe passage (1051), and the end pipe passage (1051) is connected to the hydraulic cavity (1071) of the rubber sleeve; the first packer (1) also includes a pressure relief sleeve (104) for relieving pressure in the hydraulic cavity (1071) of the rubber sleeve, and a pressure relief inner liner (102) for moving the pressure relief sleeve (104) up and down is screwed to the inner side of the pressure relief sleeve (104); a pressure relief outer sleeve (103) is also provided on the outer side of the pressure relief sleeve (104), and a pressure relief hole (1031) communicating with the outside is opened on the side wall of the pressure relief outer sleeve (103).

9. The stratified gas injection control system as described in claim 7, characterized in that, The side wall of the liquid inlet pipe (110) is also provided with a second axial passage (1104), and the inner side wall of the liquid inlet pipe (110) is also provided with a venting groove (1106) that communicates with the second axial passage (1104); the inner side of the liquid inlet pipe (110) is also provided with an emergency pressure relief sleeve (113) for venting the hydraulic chamber (1071) of the rubber sleeve.

10. A method for controlling stratified gas injection, employing a stratified gas injection control system as described in any one of claims 1-9, characterized in that, include: The tubing is inserted into the oil well at a predetermined position; The packer is set in the oil well by injecting pressurized fluid; For each adjustable air nozzle located in different oil layers, the required flow rate is first determined, and then the nozzle to be blocked in the adjustable air nozzle is determined according to the required flow rate. Then, the nozzle to be blocked is blocked by the ball thrower and the blocking ball. Different oil layers are injected with air through various adjustable air nozzles.

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