A method and system for unblocking a formation of an oil well using a gas

Abstract

The application relates to the technical field of oilfield formation plugging removal, in particular to a method and system for removing plugging of an oil well formation by using gas. The method comprises the following steps: compressing non-combustible gas to a preset pressure; and feeding the non-combustible gas into a plugging layer of the oil well in the form of a jet explosion; wherein the preset pressure is 10 MPa-30 MPa. The system comprises a central rod provided with a gas channel; a jet explosion device arranged in the gas channel, comprising a gas conveying pipeline, a hollow telescopic unit, a pressure relief cavity, a pressure relief part and at least one jet explosion port; the jet explosion port is arranged on the inner wall of the central rod and is communicated with the gas channel; the pressure relief part is arranged in the gas conveying pipeline and is communicated with the pressure relief cavity; the pressure relief cavity is arranged in the hollow telescopic unit; one end of the gas conveying pipeline is communicated with the gas channel and the gas conveying pipeline is communicated with the pressure relief cavity. The pressure and jetting mode of the non-combustible gas are limited, secondary precipitation is not generated, micro cracks can be generated to improve the seepage conditions of the formation, and the water-sensitive formation is not damaged.

Description

Technical Field

[0001] This application relates to the field of oilfield formation unblocking technology, and in particular to a method and system for unblocking oil well formations using gas. Background Technology

[0002] During oil well production, blockages can occur due to various reasons (such as incompatibility of influent fluids, migration of formation particles, and consolidation of asphalt and wax in the near-wellbore zone), leading to a decrease in near-wellbore permeability and consequently, a drop in production. For these types of wells, acidizing and physical methods are generally used to remove the blockage.

[0003] Acidizing unblocking works by using acidic unblocking agents to dissolve formation blockages without creating fractures, but it sometimes leads to secondary precipitation. Physical unblocking methods utilize ultrasound, negative pressure, oscillating cavitation, and plasma pulses for unblocking. While physical unblocking techniques are effective near-wellbore, their generally weak energy makes it difficult to improve near-wellbore permeability. Furthermore, current chemical and physical unblocking methods cause damage, especially in water-sensitive formations. Therefore, developing a gas-based unblocking method to effectively unblock formations while avoiding secondary precipitation and damage to water-sensitive formations is a pressing technical problem. Summary of the Invention

[0004] This application provides a method and system for unblocking oil well formations using gas, in order to solve the problem that existing methods of unblocking oil wells are prone to secondary precipitation and damage to water-sensitive formations.

[0005] In a first aspect, this application provides a method for unblocking oil well formations using gas, the method comprising:

[0006] Compress the non-flammable gas to a preset pressure;

[0007] The non-combustible gas is introduced into the oil well plugging layer by means of explosive jet to unblock the oil well formation;

[0008] The preset pressure is 10MPa to 30MPa.

[0009] Optionally, the non-flammable gas includes at least one of carbon dioxide, nitrogen, carbon tetrachloride, hydrogen chloride, chlorine, and inert gas.

[0010] Optionally, the depth of the oil well plugging layer from the oil well surface is ≥10m.

[0011] Secondly, this application provides a system for unblocking oil well formations using gas, the system comprising:

[0012] A central rod, wherein a gas passage is provided inside the central rod;

[0013] A detonating jet device is provided within the gas channel. The detonating jet device includes a gas supply pipe, a hollow telescopic unit, a pressure relief chamber, a pressure relief section, and at least one detonation port. One end of the gas supply pipe is connected to the gas channel. The pressure relief section is provided within the gas supply pipe and is connected to the pressure relief chamber. The pressure relief chamber is located within the hollow telescopic unit to enable the hollow telescopic unit to expand and contract within the gas channel and compress the non-combustible gas.

[0014] The detonation nozzle is located on the inner wall of the central rod, and the air inlet of the detonation nozzle is abutted against one end of the hollow telescopic unit. The hollow telescopic unit is located in the gas channel to realize the detonation jet of non-flammable gas from the detonation nozzle.

[0015] Optionally, the hollow telescopic unit includes a base, a piston, and a compression spring. The base is located inside the central rod, one end of the compression spring is nested on the base, and the other end of the compression spring abuts against the piston, so as to enable the piston of the hollow telescopic unit to slide within the gas channel.

[0016] Optionally, the piston has a hollow channel that connects to the pressure relief chamber, and the compression spring is located inside the hollow channel.

[0017] Optionally, a gas storage chamber is provided between the piston and the gas passage, the diameter of the gas storage chamber is smaller than the diameter of the piston, and the depth of the gas storage chamber is smaller than the depth of the explosion port.

[0018] Optionally, the pressure relief section includes a first pressure relief valve, a second pressure relief valve, and a pressure relief hole. The first pressure relief valve is located at one end of the gas transmission pipeline to control the gas pressure in the gas transmission pipeline. The first pressure relief valve is connected to the second pressure relief valve, and the second pressure relief valve is connected to the pressure relief hole to control the gas pressure in the gas transmission pipeline.

[0019] Optionally, the system further includes:

[0020] At least one anti-surge plate is provided on the outer wall of the central rod, and at least one well-washing channel is provided on the anti-surge plate;

[0021] The anti-impact disc is disposed above the explosive jet device; and / or,

[0022] The anti-impact plate is located below the explosive jet device.

[0023] Optionally, the system further includes:

[0024] At least one centralizer, the centralizer comprising an elastic support ring and a curved fixing screw, the elastic support ring being fixed to the outer wall of the central rod, the curved fixing screw being fixedly connected to the elastic support ring, and the curved fixing screw being abutting against the oil well pipeline;

[0025] The centralizer is located between the anti-impact plate and the explosive jet device.

[0026] The technical solutions provided in this application have the following advantages compared with the prior art:

[0027] This application provides a method for unblocking oil well formations using gas. Compared to traditional chemical and physical unblocking methods, this method uses non-flammable gas as the main unblocking material and limits the pressure and injection method of the non-flammable gas. The non-flammable gas is ejected under high pressure through a burst. The high-pressure non-flammable gas generates a gas shock wave in the oil well pipeline due to gas pressure, thereby unblocking the blockage through vibration and agitation without producing secondary precipitation. At the same time, because the high-pressure non-flammable gas has high energy, it can generate micro-fractures to improve formation seepage conditions without producing other fluids, thus avoiding damage to water-sensitive formations. Therefore, by using non-flammable gas at a preset pressure, the method can effectively unblock the formation while avoiding secondary precipitation and damage to water-sensitive formations. Attached Figure Description

[0028] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A flowchart illustrating the method provided in the embodiments of this application;

[0031] Figure 2 This is a schematic diagram of the system provided in the embodiments of this application;

[0032] Figure 3 A schematic diagram of the explosive jet device provided in this application example;

[0033] Figure 4 This is a schematic diagram of the anti-impact disc structure provided in an embodiment of this application;

[0034] Figure 5 This is a schematic diagram of the centralizer structure provided in an embodiment of this application;

[0035] Figure 6 This is a schematic diagram of a hexahedral mesh model simulation of a secondary impact under a nitrogen pressure of 30 MPa, as provided in Embodiment 7 of this application.

[0036] Among them, 1-center rod, 11-gas channel, 2-explosive jet device, 21-gas pipeline, 22-hollow telescopic unit, 221-base, 222-piston, 223-compression spring, 224-hollow channel, 23-pressure relief chamber, 24-pressure relief part, 241-first pressure relief valve, 242-second pressure relief valve, 243-pressure relief hole, 25-explosive nozzle, 26-gas storage chamber, 3-anti-impact plate, 31-well washing channel, 4-centralizer, 41-elastic support ring, 42-curved fixing screw. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0039] like Figure 1 As shown in the figure, this application provides a method for unblocking oil well formations using gas, the method comprising:

[0040] S1. Compress the non-flammable gas to a preset pressure;

[0041] S2. The non-combustible gas is introduced into the oil well plugging layer by means of a jet to unblock the oil well formation;

[0042] The preset pressure is 10MPa to 30MPa.

[0043] In this embodiment of the application, the positive effect of limiting the preset pressure to 10MPa to 30MPa is that within this pressure range, the pressure of the non-combustible gas can meet the requirements for unblocking, while avoiding damage to water-sensitive formations caused by excessive pressure. Furthermore, within this pressure range, microcracks can be generated at the blockage site to improve formation seepage conditions.

[0044] In some alternative embodiments, the non-flammable gas includes at least one of carbon dioxide, nitrogen, carbon tetrachloride, hydrogen chloride, chlorine, and inert gases.

[0045] In this embodiment of the application, the specific composition of the non-flammable gas is defined, which can effectively ensure that the gas can reach the preset pressure range after compression. It can also ensure that no flammable gas or other flammable materials in the oil well will react during the explosion stage, thus preventing a safety accident.

[0046] Inert gases refer to the elemental forms of Group 0 elements, also known as rare gases, with helium or argon being the most commonly used.

[0047] In some alternative implementations, the well plugging layer is at a depth of ≥10m from the well surface.

[0048] In this embodiment of the application, the positive effect of limiting the depth of the plugging layer from the oil well surface to ≥10m is that within this depth range, since this application uses high-pressure gas explosion, and the gas can still maintain a relatively low pressure during pipeline transportation, it can achieve transportation at a deeper depth, thereby enabling the method to be used for plugging oil wells below 10m.

[0049] like Figure 2 As shown, based on a general inventive concept, this application provides a system for unblocking oil well formations using gas, the system comprising:

[0050] Central rod 1, wherein a gas channel 11 is provided inside the central rod 1;

[0051] A detonating jet device 2 is disposed within the gas channel 11. The detonating jet device 2 includes a gas supply pipe 21, a hollow telescopic unit 22, a pressure relief chamber 23, a pressure relief section 24, and at least one detonation port 25. One end of the gas supply pipe 21 is connected to the gas channel 11. The pressure relief section 24 is disposed within the gas supply pipe 21 and is connected to the pressure relief chamber 23. The pressure relief chamber 23 is disposed within the hollow telescopic unit 22 to enable the hollow telescopic unit 22 to extend and retract within the gas channel 11 and compress the non-combustible gas.

[0052] The detonation nozzle 25 is located on the inner wall of the central rod 1. The air inlet of the detonation nozzle 25 is abutted against one end of the hollow telescopic unit 22. The hollow telescopic unit 22 is located in the gas channel 11 to realize the detonation jet of non-combustible gas by the detonation nozzle 25.

[0053] In this embodiment, a detonating jet device 2 and a central rod 1 are introduced as a system for unblocking the well. Gas is introduced using the central rod 1, and the pressure relief section 24 is closed. This allows the gas to be compressed by the extension of the hollow telescopic unit 22 of the detonating jet device 2. After reaching the preset pressure, the pressure relief section 24 is opened to release the pressure, causing the hollow telescopic unit 22 to contract. This connects the detonation port 25 with the gas channel 11, allowing the gas to be compressed by the detonating jet device 2 and ejected through the detonation port 25, thereby unblocking the oil well.

[0054] The detonation port 25 refers to the outlet from which non-flammable gas is ejected. There can be multiple ports or only one port. Generally, two ports are set, and the two detonation ports 25 need to be set symmetrically to ensure that the balance of the central rod 1 is maintained while the gas is ejected and ejected, so as to avoid the central rod 1 colliding with the oil well channel and causing a safety accident.

[0055] The system is implemented based on the above method. The specific steps of the method can be referred to the above embodiments. Since the system adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0056] In some optional embodiments, the hollow telescopic unit 22 includes a base 221, a piston 222, and a compression spring 223. The base 221 is disposed inside the central rod 1. One end of the compression spring 223 is nested on the base 221, and the other end of the compression spring 223 abuts against the piston 222, so as to realize that the piston 222 of the hollow telescopic unit 22 slides in the gas channel 11.

[0057] In this embodiment, the hollow telescopic unit 22 is specifically composed of a base 221, a piston 222, and a compression spring 223. When the pressure relief section 24 is closed, as gas continuously enters the pressure relief chamber 23, the gas pushes the piston 222 into the gas channel 11, causing the piston 222 to break the connection between the explosion port 25 and the gas channel 11, thereby sealing the explosion port 25 and causing the gas pressure in the gas channel 11 to continuously increase. At this time, the compression spring 223 extends and retracts, keeping the piston 222 in an extended state. When the gas pressure reaches a preset pressure stage, the pressure relief section 24 is opened, so that the pressure in the pressure relief chamber 23 is less than the pressure in the gas channel 11. Under the action of pressure and the elastic force of the compression spring 223, the piston 222 is stretched towards the base 221, and the high-pressure gas in the gas channel 11 is released through the explosion port 25, thereby forming agitated gas fluctuations in the oil well pipeline and relieving the blockage of the oil well plug.

[0058] In some alternative embodiments, the piston 222 is provided with a hollow channel 224, the hollow channel 224 is connected to the pressure relief chamber 23, and the compression spring 223 is disposed in the hollow channel 224.

[0059] In this embodiment, a hollow channel 224 is provided inside the piston 222, which not only expands the volume of the pressure relief chamber 23 and facilitates the extension and retraction of the piston 222, but also increases the extension and retraction length of the compression spring 223 and reduces the extension and retraction performance requirements of the compression spring 223.

[0060] In some optional embodiments, a gas storage chamber 26 is provided between the piston 222 and the gas passage 11, the diameter of the gas storage chamber 26 being smaller than the diameter of the piston 222, and the depth of the gas storage chamber 26 being smaller than the depth of the explosion port 25.

[0061] In this embodiment of the application, by setting up a gas storage chamber 26 and limiting the size and depth of the gas storage chamber 26, the pressure of the gas on the piston 222 can be increased through the gas storage chamber 26, which is smaller than the gas channel 11, so that the high-pressure gas can be ejected from the system more quickly through the detonation port 25.

[0062] In some optional embodiments, the pressure relief section 24 includes a first pressure relief valve 241, a second pressure relief valve 242, and a pressure relief hole 243. The first pressure relief valve 241 is located at one end of the gas transmission pipeline 21 to control the gas pressure of the gas transmission pipeline 21. The first pressure relief valve is connected to the second pressure relief valve, and the second pressure relief valve is connected to the pressure relief hole 243 to control the gas pressure of the gas transmission pipeline 21.

[0063] In this embodiment, the specific composition of the pressure relief section 24 is defined. Through two pressure relief valves, not only can the pressure of the pressure relief be reduced, but the pressure value of the first pressure relief valve can also be used to determine whether the pressure in the pipeline has reached the preset pressure, which facilitates accurate pressure relief operation. At the same time, the pressure value of the second pressure relief valve can also be used to determine when the pressure in the pressure relief chamber 23 can be balanced with the compression spring 223, so that the piston 222 is in the balanced position, thereby realizing the repeated movement of the compression spring 223 and realizing the opening and closing of the explosion port 25.

[0064] To ensure the safety of the pressure relief hole 243, this application also provides a plug, which is located at the air outlet end of the pressure relief hole 243 to prevent impurities from entering the pressure relief hole 243 and causing blockage.

[0065] In some alternative implementations, the system further includes:

[0066] At least one anti-impact plate 3 is provided on the outer wall of the central rod 1, and at least one well-washing channel 31 is provided on the anti-impact plate 3;

[0067] The anti-impact disc 3 is positioned above the explosive jet device 2; and / or,

[0068] The anti-impact disc 3 is located below the explosive jet device 2.

[0069] In this embodiment, the anti-surge plate 3 is introduced along with the well-washing channel 31. The anti-surge plate 3 can block the gas shock wave generated from moving up and down in the vertical direction, thereby reducing its propagation into the formation. At the same time, the well-washing channel 31 can ensure that well-washing and pressure operations can be carried out after or during the unblocking process.

[0070] To better realize the function of the anti-impact plate 3, an anti-impact plate 3 can generally be set above and below the explosion port 25 of the explosion jet device 2, so as to ensure the unblocking effect of the gas shock wave generated by the gas.

[0071] The anti-shock plate 3 is preferably made of rubber, which can effectively block the gas shock wave from moving up and down in the vertical direction and improve the unblocking efficiency.

[0072] To ensure pressure balance, the well-washing channels 31 are evenly distributed on the anti-surge plate 3, and the number of well-washing channels 31 is generally set to 4 according to the operation requirements and pressure requirements of the oil well.

[0073] In some alternative implementations, the system further includes:

[0074] At least one centralizer 4, the centralizer 4 including an elastic support ring 41 and a curved fixing screw 42, the elastic support ring 41 being fixed to the outer wall of the central rod 1, the curved fixing screw 42 being fixedly connected to the elastic support ring 41, and the curved fixing screw 42 being abutting against the oil well pipeline;

[0075] The centralizer 4 is located between the anti-impact plate 3 and the explosive jet device 2.

[0076] In this embodiment, a centralizer 4 is introduced into the system. The combination of an elastic support ring 41 and a curved fixing screw 42 is used. The curved fixing screw 42 abuts against the inner wall of the oil well pipeline, while the elastic support ring 41 connects the curved fixing screw 42 and the central rod 1. When the gas is ejected, the central rod 1 will swing under the action of the ejection force. At this time, the curved fixing screw 42 is subjected to pressure and abuts against the inner wall of the oil well pipeline. At this time, the elastic support ring 41 relieves part of the pressure on the curved fixing screw 42, preventing the central rod 1 from swinging, thereby preventing the disengagement phenomenon at the connection of the central rod 1.

[0077] The elastic support ring 41 refers to an elastic ring-shaped support, including rubber rings, plastic rings and elastic metal rings. The elastic support ring 41 is generally distributed at both ends where the curved fixing screw 42 and the center rod 1 contact.

[0078] The curved fixing screw 42 refers to a long screw with a curved surface. In this stabilizer 4, there can be multiple curved fixing screws 42, but they must be evenly distributed circumferentially on the surface of the central rod 1 to better prevent the central rod 1 from swinging.

[0079] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0080] Example 1

[0081] like Figure 1 As shown, a method for unblocking oil well formations using gas includes:

[0082] S1. Compress the non-flammable gas to a preset pressure;

[0083] S2. Inject non-flammable gas into the oil well plugging layer using a jet injection method to unblock the oil well formation;

[0084] The preset pressure is 20 MPa.

[0085] Non-flammable gases include at least one of carbon dioxide, nitrogen, carbon tetrachloride, hydrogen chloride, chlorine, and inert gases.

[0086] The depth of the plugging layer from the well surface is ≥10m.

[0087] like Figure 2 and Figure 3 As shown, a system for unblocking oil well formations using gas includes:

[0088] A detonating jet device 2 is disposed within the gas channel 11. The detonating jet device 2 includes a gas supply pipe 21, a hollow telescopic unit 22, a pressure relief chamber 23, a pressure relief section 24, and at least one detonation port 25. One end of the gas supply pipe 21 is connected to the gas channel 11. The pressure relief section 24 is disposed within the gas supply pipe 21 and is connected to the pressure relief chamber 23. The pressure relief chamber 23 is disposed within the hollow telescopic unit 22 to enable the hollow telescopic unit 22 to extend and retract within the gas channel 11 and compress the non-combustible gas.

[0089] The detonation nozzle 25 is located on the inner wall of the central rod 1. The air inlet of the detonation nozzle 25 is abutted against one end of the hollow telescopic unit 22. The hollow telescopic unit 22 is located in the gas channel 11 to realize the detonation jet of non-combustible gas by the detonation nozzle 25.

[0090] Example 2

[0091] Comparing Example 2 with Example 1, the difference between Example 2 and Example 1 is as follows:

[0092] like Figure 3 As shown, the hollow telescopic unit 22 includes a base 221, a piston 222 and a compression spring 223. The base 221 is located inside the central rod 1. One end of the compression spring 223 is nested on the base 221, and the other end of the compression spring 223 abuts against the piston 222, so that the piston 222 of the hollow telescopic unit 22 can slide in the gas channel 11.

[0093] The piston 222 has a hollow channel 224 inside, which connects to the pressure relief chamber 23. The compression spring 223 is located inside the hollow channel 224.

[0094] A gas storage chamber 26 is provided between the piston 222 and the gas passage 11. The diameter of the gas storage chamber 26 is smaller than the diameter of the piston 222, and the depth of the gas storage chamber 26 is smaller than the depth of the explosion port 25.

[0095] Example 3

[0096] Comparing Example 3 with Example 1, the difference between Example 3 and Example 1 is as follows:

[0097] like Figure 3 As shown, the pressure relief section 24 includes a first pressure relief valve 241, a second pressure relief valve 242, and a pressure relief hole 243. The first pressure relief valve 241 is located at one end of the gas transmission pipeline 21 to control the gas pressure of the gas transmission pipeline 21. The first pressure relief valve is connected to the second pressure relief valve, and the second pressure relief valve is connected to the pressure relief hole 243 to control the gas pressure of the gas transmission pipeline 21.

[0098] Example 4

[0099] Comparing Example 4 with Example 1, the difference between Example 4 and Example 1 is as follows:

[0100] like Figure 2 and Figure 4 As shown, the system also includes:

[0101] Two anti-impact plates 3 are provided on the outer wall of the central rod 1, and at least one well-washing channel 31 is provided on the anti-impact plate 3.

[0102] An anti-impact disc 3 is positioned above the explosive jet device 2; and / or,

[0103] The anti-impact plate 3 is located below the explosive jet device 2.

[0104] Example 5

[0105] Comparing Example 5 with Example 1, the difference between Example 5 and Example 1 is as follows:

[0106] like Figure 2 and Figure 5 As shown, the system also includes:

[0107] Two centralizers 4, each centralizer 4 includes an elastic support ring 41 and a curved fixing screw 42. The elastic support ring 41 is fixed to the outer wall of the central rod 1. The curved fixing screw 42 is fixedly connected to the elastic support ring 41. The curved fixing screw 42 abuts against the oil well pipeline.

[0108] The centralizer 4 is located between the anti-impact plate 3 and the explosive jet device 2.

[0109] Example 6

[0110] Comparing Example 6 with Example 1, the difference between Example 6 and Example 1 is as follows:

[0111] The preset pressure is 12 MPa.

[0112] Example 7

[0113] Comparing Example 7 with Example 1, the difference between Example 7 and Example 1 is as follows:

[0114] The preset pressure is 30 MPa.

[0115] Comparative Example 1

[0116] Comparative Example 1 and Example 1 will be compared. The difference between Comparative Example 1 and Example 1 is as follows:

[0117] The chemical unblocking method is used directly, and the chemical agents are acidic systems, generally including hydrochloric acid systems, oxalic acid systems, polyhydrogen acid systems, organophosphate systems, etc.

[0118] Comparative Example 2

[0119] Comparative Example 2 and Example 1 will be compared. The difference between Comparative Example 2 and Example 1 is as follows:

[0120] The preset pressure is 5 MPa.

[0121] Comparative Example 3

[0122] Comparative Example 3 and Example 1 will be compared. The difference between Comparative Example 3 and Example 1 is as follows:

[0123] The preset pressure is 40 MPa.

[0124] Relevant experimental and effect data: Secondary impact-induced cracking simulation was carried out using a hexahedral mesh model under a nitrogen pressure of 30 MPa. The simulation software used was ANSYS.

[0125] Simulation results show that in Comparative Example 2, the blockage layer could not be removed due to insufficient pressure; while in Comparative Example 3, although the explosion could proceed smoothly due to excessive pressure, the service life of the explosion nozzle was short due to the limitation of the spring force in the explosion nozzle. At the same time, the excessive ejection force caused the central rod to easily disengage.

[0126] Compared to Examples 1-7, Comparative Example 1 uses chemical agents that are prone to secondary precipitation at the outlet of the central rod, thus clogging the central rod, and may also cause damage in water-sensitive formations.

[0127] Simulations in Examples 1-7 show that when the detonation pressure reaches 30 MPa, the force generated after ejection from the injection chamber is 27 MPa, producing formation fractures of more than 5.5 m. This has a good effect on improving formation permeability and unblocking and increasing production.

[0128] One or more technical solutions in the embodiments of this application have at least the following technical effects or advantages:

[0129] (1) The present application provides a method for unblocking oil well formations using gas. It uses non-flammable gas as the main material for unblocking and limits the pressure and injection method of the non-flammable gas. It does not produce secondary precipitation, can generate microcracks to improve formation seepage conditions, and will not damage water-sensitive formations. It achieves effective unblocking of formations while avoiding secondary precipitation and damage to water-sensitive formations.

[0130] (2) The method of using gas to unblock oil well formations provided in this application embodiment can be applied to water-sensitive formations to achieve effective unblocking; it can also be used in low-permeability oil layers to improve the seepage conditions in the near-wellbore zone.

[0131] (3) The method of using gas to unblock oil well formations provided in this application embodiment has the following advantages compared with physical unblocking technology: first, the explosive force is large, which can play a dual role of unblocking and improving formation permeability; second, the unblocking is achieved by using gas, which is applicable to water-sensitive formations, coalbed methane and other formations.

[0132] (4) The system provided in this application embodiment uses gas to unblock the formation of oil wells, which can ensure that the generated gas shock wave can be effectively transmitted into the formation and the blockage can be efficiently discharged. At the same time, it can achieve well washing and pressure operation in special circumstances.

[0133] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0134] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the orientation shown in the accompanying drawings. Furthermore, in the description of this application, the terms "comprising," "including," etc., mean "including but not limited to."

[0135] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any actual relationship or order between these entities or operations. In this document, "and / or" describes the association between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0136] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A system for unblocking oil well formations using gas, characterized in that, The system includes: A central rod (1) is provided with a gas passage (11); A jetting device (2) is provided in the gas channel (11). The jetting device (2) includes a gas supply pipe (21), a hollow telescopic unit (22), a pressure relief chamber (23), a pressure relief part (24), and at least one jetting port (25). One end of the gas supply pipe (21) is connected to the gas channel (11). The pressure relief part (24) is provided in the gas supply pipe (21). The pressure relief part (24) is connected to the pressure relief chamber (23). The pressure relief chamber (23) is provided in the hollow telescopic unit (22) so as to realize the expansion and contraction of the hollow telescopic unit (22) in the gas channel (11) and compress the non-flammable gas. The detonation port (25) is located on the inner wall of the central rod (1). The air inlet of the detonation port (25) is connected to one end of the hollow telescopic unit (22). The hollow telescopic unit (22) is located in the gas channel (11) to realize the detonation jet of the detonation port (25) on the non-combustible gas.

2. The system according to claim 1, characterized in that, The hollow telescopic unit (22) includes a base (221), a piston (222), and a compression spring (223). The base (221) is located inside the central rod (1). One end of the compression spring (223) is nested on the base (221), and the other end of the compression spring (223) abuts against the piston (222) to enable the piston (222) of the hollow telescopic unit (22) to slide within the gas channel (11).

3. The system according to claim 2, characterized in that, The piston (222) is provided with a hollow channel (224), which is connected to the pressure relief chamber (23), and the compression spring (223) is located in the hollow channel (224).

4. The system according to claim 2, characterized in that, A gas storage chamber (26) is provided between the piston (222) and the gas passage (11). The diameter of the gas storage chamber (26) is smaller than the diameter of the piston (222), and the depth of the gas storage chamber (26) is smaller than the depth of the explosion port (25).

5. The system according to claim 1, characterized in that, The pressure relief section (24) includes a first pressure relief valve (241), a second pressure relief valve (242), and a pressure relief hole (243). The first pressure relief valve (241) is located at one end of the gas pipeline (21) to control the gas pressure of the gas pipeline (21). The first pressure relief valve is connected to the second pressure relief valve, and the second pressure relief valve is connected to the pressure relief hole (243) to control the gas pressure of the gas pipeline (21).

6. The system according to claim 1, characterized in that, The system also includes: At least one anti-surge plate (3) is provided on the outer wall of the central rod (1), and at least one well-washing channel (31) is provided on the anti-surge plate (3); The anti-impact disc (3) is positioned above the explosive jet device (2); and / or, The anti-impact plate (3) is located below the explosive jet device (2).

7. The system according to claim 6, characterized in that, The system also includes: At least one centralizer (4), the centralizer (4) includes an elastic support ring (41) and a curved fixing screw (42), the elastic support ring (41) is fixed to the outer wall of the central rod (1), the curved fixing screw (42) and the elastic support ring (41) are fixedly connected, and the curved fixing screw (42) is abutted against the oil well pipeline; The centralizer (4) is located between the anti-impact plate (3) and the explosive jet device (2).

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