Long-combustion pulse type clean detonation system and performance testing method

Abstract

The invention discloses a long-combustion pulse type clean detonation system and a performance testing method, and relates to the technical field of oil and gas well perforation. The device comprises a test target, a sleeve is installed in the test target, the top of the sleeve is in threaded connection with a sleeve joint, the center position of the sleeve joint is in threaded connection with a pulse detonation grain assembly, and the middle position of the pulse detonation grain assembly is in threaded connection with an ignition plug. The high-combustion-rate propellant and the low-combustion-rate propellant are poured in sequence to form a gradual-change-combustion-rate propelling system, the combustion mode is layer-by-layer combustion, high-combustion-rate pressurization is fast, formation fracturing is facilitated, later low-combustion-rate long-time combustion is formed, formation fracture extension is facilitated, high-combustion-rate and low-combustion-rate alternate combustion is achieved, and multiple pulse type pressure fluctuation is formed after combustion; the combustion time can be prolonged, the seam extending effect can be improved, the combustion reliability can also be improved, the outer shell is a combustible shell, few residues are left after combustion, and it is guaranteed that a shaft is clean.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas well perforation, in particular to a long combustion pulse clean deflagration system and a performance testing method. Background Art

[0002] In the process of oil and gas well development, facing wells with dense formations, low porosity and low permeability, wells with oil and water in the same layer, or wells close to low water but need fracturing, the use of deflagration fracturing technology to apply pressure to the formation perforation channel to form multiple cracks, increase the conductivity of the reservoir, and improve the oil flow efficiency is currently the main means of increasing oil field production. However, the existing fracturing bombs are caseless fracturing bombs, which are ignited by detonating cords or explosive columns to form a fragmentation-type surface-increasing combustion. Under the high-pressure environment of the wellbore, the burning time is only tens of milliseconds to hundreds of milliseconds. It has a good unblocking effect for contaminated wells and wells with serious blockages, but the cracks formed by the cracking are short and narrow, which is not conducive to communicating the production layer. At the same time, the ground test of the combustion performance of deflagration fracturing mainly uses high-energy gas generated by deflagration at normal temperature and pressure to break the concrete target, and then measures the length and width of the cracks in the concrete target. Although this method can reflect the energy released by the combustion of the deflagration fracturing bomb to a certain extent, it cannot truly simulate the effect of the deflagration fracturing under the high-pressure environment of the wellbore, and cannot give the correct value for the estimation and calculation of the operating capacity. Therefore, this test method has great limitations and is misleading.

[0003] The existing patent (CN201711428950.4) discloses a safe high-energy gas fracturing device, including an ignition ring and a gas-producing ring. The device is filled from the inside out by using an ignition ring of energetic material that does not produce gas and a gas-producing ring of insensitive gas-producing agent. Although it is safer during use, it does not solve the problem of fast combustion underground. For this reason, we propose a long-burning pulse clean deflagration system and a performance testing method. Summary of the invention

[0004] The purpose of the present invention is to provide a long-burning pulse clean deflagration system and a performance testing method, which utilizes high and low burning rate propellants to be cast in sequence to form a gradual burning rate propulsion system, and adopts an electric heater ignition method to ignite the propellant column. The combustion method is layer-by-layer combustion. The high burning rate increases the pressure quickly, which is beneficial to formation fracturing. The subsequent low burning rate forms a long-term combustion, which is beneficial to the extension of formation cracks.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a long-burning pulse clean deflagration system and a performance testing method, comprising a test target, a sleeve is installed inside the test target, a sleeve joint is threadedly connected to the top of the sleeve, a pulse deflagration charge column assembly is threadedly connected to the center of the sleeve joint, an ignition plug is threadedly connected to the middle of the pulse deflagration charge column assembly, a sealed conductive pin is installed inside the ignition plug, a pressure cap is coaxially installed above the sealed conductive pin, and the pressure cap is threadedly connected to the ignition plug, the sealed conductive pin is located in the inner hole of the pulse deflagration charge column assembly, and is used to ignite the pulse deflagration charge column assembly, and when the pulse deflagration charge column assembly burns, high and low burning rates are alternately burned to form high-temperature and high-pressure gas to act on the test target;

[0006] The top of the sleeve joint is threadedly connected with a pressure joint, and the pressure joint is located on one side of the ignition plug.

[0007] Furthermore, the test target includes a rock layer built on the outside of the casing, the rock layer and the casing have a clearance fit, the fitting clearance is no more than 2 mm, and is filled with concrete, a concrete layer is poured on the outside of the rock layer, and the outer surface of the concrete layer is covered with a target sleeve;

[0008] The side wall of the casing is provided with a plurality of through holes 1 in the radial direction, and the side wall of the rock layer is provided with through holes 2 in the radial direction at positions corresponding to the through holes 1 on the casing, and one end of the through holes 2 located on the outside is sealed by concrete.

[0009] Furthermore, the pulse deflagration charge column assembly is located in the casing, and the space between the pulse deflagration charge column assembly and the casing is filled with clean water. The pulse deflagration charge column assembly includes a combustible shell threadedly connected to the casing joint, and a plurality of high-burning-rate charge columns and low-burning-rate charge columns are cast from bottom to top inside the combustible shell, and the high-burning-rate charge columns and the low-burning-rate charge columns are cast alternately in sequence.

[0010] Furthermore, a truncated cone-shaped inner cavity is provided at the top of the combustible shell, and the cone angle of the truncated cone inner cavity is set to 0°-120°, the depth is greater than 3mm, and a sealing ring is provided between the top of the combustible shell and the sleeve joint.

[0011] Furthermore, an electric heater is installed at the bottom end of the combustible shell, the electric heater is installed in the bottom layer of high-burning rate powder column, the top end of the electric heater is connected to a quick plug wire, and the top end of the quick plug wire is connected to the sealed conductive pin.

[0012] Furthermore, sealing rings are provided between the sleeve and the sleeve joint, and between the combustible shell and the ignition plug.

[0013] Furthermore, the combustible shell is made of aluminum alloy, the outer diameter of the combustible shell is set to 30mm-178mm, and the wall thickness is not less than 5mm.

[0014] Furthermore, the thickness of the low burning rate grain and the high burning rate grain are both greater than 50 mm, and both the low burning rate grain and the high burning rate grain are made of ammonium perchlorate, terminal hydroxyl polybutadiene and aluminum powder. The burning rate of the low burning rate grain is 1 mm / s-5 mm / s, and the burning rate of the high burning rate grain is 8 mm / s-12 mm / s.

[0015] Furthermore, the sleeve is configured as a round tube, the outer diameter of the round tube is greater than 60 mm, the height of the round tube is configured to be 300 mm-1800 mm, the bottom of the round tube is closed, and an opening is configured at the top.

[0016] According to a second aspect of the present invention, the present invention provides a performance test method for a long combustion pulse clean type deflagration system and a performance test method, which is used to perform a combustion performance test on the above-mentioned long combustion pulse clean type deflagration system and a performance test method, comprising the following steps:

[0017] S1. First, thread the pulse deflagration charge assembly to the ignition plug, and then install the pressure cap and the sealing conductive pin in the ignition plug;

[0018] S2. Install the sealed conductive pin installed on the ignition plug in the inner hole of the pulse deflagration charge, and connect the sealed conductive pin to the electric heater through a quick plug wire;

[0019] S3. Thread the casing joint to the casing of the test target, further thread the pressure joint to the casing joint, connect the pressure pipeline and the pressure device to pressurize the casing, connect the sealed conductive pin and wire, pass 110V DC, and ignite successfully in about 15 seconds;

[0020] S4. Finally, the combustion performance is reflected by testing the length, width and number of cracks formed in the target rock pores.

[0021] The present invention has at least the following beneficial effects:

[0022] 1. The present invention adopts a direct current electric heater ignition method to ignite the charge. When the electric heater is heated to above 600°C, the charge can be reliably ignited. Compared with the existing detonating cord and charge crushing center tube combustion, the charge has better combustion stability and longer burning time. In addition, the present invention uses high and low burning rate propellants to cast in sequence to form a gradual burning rate propulsion system. The combustion method is layer-by-layer combustion. The high burning rate increases the pressure quickly, which is conducive to formation fracturing. The subsequent low burning rate forms a long-term combustion, which is conducive to the extension of formation cracks. The high and low burning rates burn alternately, and multiple pulsed pressure fluctuations are formed after combustion, which can not only increase the burning time and improve the seam extension effect, but also improve the combustion reliability.

[0023] 2. The present invention adopts pulse combustion, which is conducive to forming wellbore liquid impact vibration, and is conducive to clearing the perforation compaction zone and pollution. The outer shell of the pulse deflagration column is a combustible shell, and the release gas nozzle is designed as a frustum structure, which is conducive to increasing the combustion power of the column and reducing the vibration of the pipe column. There is little residual residue in the shell after combustion, which ensures the cleanliness of the wellbore.

[0024] 3. Compared with the existing ground test of deflagration fracturing combustion performance, which adopts the method of testing the deflagration effect by using high-energy gas to crack concrete targets during deflagration at normal temperature and pressure, the present invention uses rocks with the same physical properties as the downhole formation to manufacture target targets, and prefabricates perforation holes of the same size in advance to establish a downhole deflagration test under wellbore pressure, which can more accurately test the rock cracking and seam extension effects.

[0025] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a cross-sectional schematic diagram of the overall structure of the present invention;

[0027] Figure 2 For the present invention Figure 1 A magnified view of the structure at center

[0028] Figure 3 It is a cross-sectional schematic diagram of the pulse deflagration charge assembly of the present invention;

[0029] Figure 4 It is a partial cross-sectional schematic diagram of the target structure of the test object of the present invention;

[0030] Figure 5 It is a cross-sectional schematic diagram of the casing joint structure of the present invention;

[0031] Figure 6 It is a cross-sectional schematic diagram of the ignition plug structure of the present invention.

[0032] Reference numerals:

[0033] 1. Pulse deflagration charge assembly; 101. Combustible shell; 102. Low burning rate charge; 103. High burning rate charge; 104. Electric heater; 105. Quick plug; 2. Test target; 201. Casing; 202. Rock layer; 203. Concrete layer; 204. Target sleeve; 3. Pressure joint; 4. Casing joint; 5. Ignition plug; 6. Pressure cap; 7. Sealed conductive pin; 8. Sealing ring. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0035] Embodiment 1:

[0036] See also Figure 1-Figure 6 The present invention provides a technical solution: a long-burning pulse clean deflagration system and a performance test method, comprising a test target 2, wherein a sleeve 201 is installed inside the test target 2, a sleeve 201 joint is threadedly connected to the top of the sleeve 201, a pulse deflagration charge column assembly 1 is threadedly connected to the center of the sleeve 201 joint, an ignition plug 5 is threadedly connected to the middle of the pulse deflagration charge column assembly 1, a sealed conductive pin 7 is installed inside the ignition plug 5, a pressure cap 6 is coaxially installed above the sealed conductive pin 7, and the pressure cap 6 is threadedly connected to the ignition plug 5, the sealed conductive pin 7 is located in the inner hole of the pulse deflagration charge column assembly 1, and is used to ignite the pulse deflagration charge column assembly 1, and when the pulse deflagration charge column assembly 1 burns, high and low burning rates are alternately burned to form high-temperature and high-pressure gas to act on the test target 2;

[0037] The top of the sleeve 201 joint is threadedly connected with a pressure joint 3, and the pressure joint 3 is located on one side of the ignition plug 5.

[0038] According to the technical solution of this embodiment, the test target 2 includes a rock layer 202 built on the outside of the casing 201, the rock layer 202 and the casing 201 have a clearance fit, the clearance is no more than 2 mm, and the rock layer 202 is filled with concrete, a concrete layer 203 is poured on the outside of the rock layer 202, and a target sleeve 204 is sleeved on the outer surface of the concrete layer 203;

[0039] The side wall of the casing 201 is provided with a plurality of through holes 1 in the radial direction, and the side wall of the rock layer 202 is provided with through holes 2 in the radial direction at positions corresponding to the through holes 1 on the casing 201. The diameters of through holes 1 and 2 are equal, and the outer end of through holes 2 is sealed by concrete, and the sealing length is not less than 20 mm.

[0040] Furthermore, the sleeve 201 is configured as a round tube, the outer diameter of the round tube is greater than 60 mm, and the height of the round tube can be set to 300 mm-1800 mm. According to the technical solution of this embodiment, the sleeve 201 is a 177.8 mm round tube with a height of 1600 mm. The material is steel pipe L80, and the bottom of the round tube is closed and an opening is provided at the top. A sealing ring 8 is provided between the sleeve 201 and the sleeve joint 4 to enhance the sealing performance between the two.

[0041] Furthermore, the through hole 1 is a spiral drill hole in the radial direction at a distance of 400 mm from the upper end surface of the casing 201, the through hole 1 has a hole diameter of 20 mm, the number of holes is 16, the hole spacing is 62.5 mm, and the phase is 90°.

[0042] According to the technical solution of this embodiment, the rock layer 202 is natural rock with an outer diameter of 200mm-1000mm and a height of 300mm-1800mm. The inner cavity aperture and depth are matched with the sleeve 201 gap, the matching gap is not greater than 2mm, and concrete is used for filling. Specifically, sandstone is selected as the rock with a uniaxial compressive strength of 60MPa, an outer diameter of 800mm, a height of 1600mm, and a center hole diameter of 180mm. The 177.8mm sleeve 201 is placed in the center hole and filled with concrete. Then, drilling is performed from the outside in the radial drilling direction of the sleeve 201. The drilling diameter is set to 20mm, and the outer hole is blocked with concrete with a blocking length of 20mm.

[0043] The target sleeve 204 is set as a circular iron plate, the thickness of the iron plate can be set to 1mm-3mm, the diameter is not less than 2000mm, and the height is set to 300mm-1800mm. According to the technical solution of this embodiment, the thickness of the iron plate is 2mm, the diameter is 5000mm, and the height is 1600mm. After the casing 201 and the rock layer 202 are assembled, the tool is placed in the center of the target sleeve 204. Finally, concrete is poured between the target sleeve 204 and the rock layer 202. The pouring height is 1400mm. The formula of the concrete is: cement: quartz sand: water = 2:5:1.

[0044] According to the technical solution of this embodiment, the pulse deflagration charge column assembly 1 is located in the sleeve 201, and the space between the pulse deflagration charge column assembly 1 and the sleeve 201 is filled with clean water. The pulse deflagration charge column assembly 1 includes a combustible shell 101 threadedly connected to the joint of the sleeve 201, and a sealing ring 8 is arranged between the top of the combustible shell 101 and the joint of the sleeve 201. The material of the combustible shell 101 is mainly a tube material with strength and flammability such as hard aluminum or aluminum alloy, and the outer diameter can be set to 30mm-178mm, and the wall thickness is not less than 5mm. The top of the combustible shell 101 is provided with an external thread and an annular groove, and the annular groove is used to install the sealing ring 8. The top of the inner top of the combustible shell 101 is set as a truncated cone inner cavity, and the inner cavity cone angle is set to 0°-120°, and the depth is set to be more than 3mm.

[0045] A plurality of high burning rate powder columns 103 and low burning rate powder columns 102 are poured from bottom to top inside the combustible shell 101, and the high burning rate powder columns 103 and the low burning rate powder columns 102 are poured alternately in sequence. The formula of the low burning rate powder columns 102 and the high burning rate powder columns 103 is mainly ammonium perchlorate, terminal hydroxyl polybutadiene and aluminum powder. The two are mainly adjusted by the particle size of the ammonium perchlorate used and the addition of catalysts such as iron oxide. The burning rate of the low burning rate powder column 102 is 1mm / s-5mm / s, and the burning rate of the high burning rate powder column 103 is 8mm / s-12mm / s The electric heater 104 has a power of 35W, a power supply voltage of DC 110V, a stainless steel cylindrical shape, a diameter of 6mm, and a length of 10mm. It is manufactured by a casting method. First, a certain amount of high burning rate agent is cast into the inner cavity of the combustible shell, and the electric heater 104 and the quick plug-in wire 105 are buried in the agent and solidified to form a high burning rate column 103. Then, a certain amount of low burning rate agent is cast into the combustible shell and solidified into shape. The two agents are cast into the shell in sequence, and the thickness of the column after each layer of solidification is set to be more than 50mm.

[0046] It should be noted that a sealing ring 8 is provided between the combustible shell 101 and the ignition plug 5 to enhance the sealing performance therebetween, so that a closed cavity is formed inside the combustible shell 101 .

[0047] Next, the technical solution of the present invention is described in conjunction with specific embodiments:

[0048] A long combustion pulse clean deflagration system and performance testing method, comprising:

[0049] Pulse deflagration charge assembly 1, test target 2, pressure joint 3, sleeve joint 4, ignition plug 5, pressure cap 6, sealing conductive pin 7 and sealing ring 8;

[0050] The pulse deflagration charge assembly 1 comprises a combustible shell 101, a low burning rate charge 102, a high burning rate charge 103, an electric heater 104 and a quick plug-in wire 105, wherein the combustible shell 101 is made of hard aluminum tube material, with an outer diameter of 89 mm, a wall thickness of 10 mm, a length of 1000 mm, a thread at one end of Tr60×4, an assembly sealing ring of Ф55×3.5, and a truncated cone inner cavity of the combustible shell 101 with an inner cavity cone angle of 120° and an inner cavity depth of 12 mm;

[0051] Furthermore, the formula of the low burning rate charge 102 and the high burning rate charge 103 is mainly ammonium perchlorate, terminal hydroxyl polybutadiene and aluminum powder, the particle size of the high burning rate ammonium perchlorate is 5 μm, the iron oxide content is 3%, the particle size of the low burning rate ammonium perchlorate is 150 μm, the burning rate of the low burning rate charge 102 is 3 mm / s, and the burning rate of the high burning rate charge 103 is 12 mm / s; the power of the electric heater 104 is 35W, the power supply voltage is DC 110V, the stainless steel cylinder is 6 mm in diameter, and the length is 10 mm. The pulsed deflagration charge group Component 1 is manufactured by a casting method. First, a high burning rate charge 103 is cast into the inner cavity of a combustible shell 101, and an electric heater 104 and a quick plug-in wire 105 are buried in the charge and solidified to form a high burning rate charge 103 with a charge thickness of 100 mm. Then, a certain mass of low burning rate agent is cast into the combustible shell 101 and solidified to form a charge with a thickness of 200 mm. The two agents are cast into the shell in sequence, with a total casting thickness of 700 mm. The high burning rate charge 103 is 3 layers, and the low burning rate charge 102 is 2 layers.

[0052] The test target 2 mainly includes a casing 201, rock, concrete and a target casing 204. The casing 201 is a 177.8 mm round tube with a height of 1600 mm. The material is L80 and the bottom is welded. The through hole 1 is a spiral drill hole in the radial direction at a distance of 400 mm from the upper end face. The hole diameter is 20 mm, the number of holes is 16 holes, the hole spacing is 62.5 mm, and the phase is 90°. The rock is selected as sandstone with a uniaxial compressive strength of 60 MPa, an outer diameter of 800 mm, a height of 1600 mm, and a center hole diameter of 180 mm. The 77.8 mm casing 201 is placed in the center hole and filled with concrete. Then, the casing 201 is drilled from the outside in the radial drilling direction. The drilling diameter is set to 20 mm. The outer hole is blocked with concrete. The blocking length is 20 mm. The target sleeve 204 is a circular iron plate with a thickness of 2 mm, a diameter of 5000 mm, and a height of 1600 mm. The sandstone is placed in the center of the target sleeve 204. Finally, concrete is poured between the target sleeve 204 and the rock. The pouring height is 1400 mm. The formula of concrete is: cement: quartz sand: water = 2:5:1.

[0053] The outer diameter of the pressure joint 3 is 25 mm, the designed external thread type is M20×1.5, and the assembly sealing ring 8 is Ф8×1.8.

[0054] The outside of the casing joint 4 is provided with external threads and sealing ring grooves, the external thread buckle type is 6-1 / 4"-6ACME-2G, the size of the assembly sealing ring 8 is Ф150×5.3, the internal thread of the center hole is Tr60×4, the internal thread of the connecting pressure head is M20×1.5 20mm away from the center hole, and a Ф3mm through hole is provided at the lower end of the internal thread hole.

[0055] The ignition plug 5 is provided with external threads and sealing ring grooves on the outside, the external thread buckle type is M40×2, the size of the assembly sealing ring 8 is Ф36×2.65, the center hole is provided with an internal thread of M10×1, and a Ф5mm through hole is provided at the bottom.

[0056] Specifically, after the pulse deflagration charge column assembly 1 is connected to the casing joint 4 and lowered into the test target 2, the designed pressure is applied to the casing joint 4, and the sealed conductive pin 7 is connected and the wire is powered on for ignition. The high and low burning rate propellants burn layer by layer. The high burning rate increases the pressure quickly and the formation quickly fractures. The low burning rate forms a long-term combustion and extends longer formation cracks. The high and low burning rates burn alternately to form high-temperature and high-pressure gases to act on the test target 2, forming multiple cracks. The number, length and width of the cracks are measured, and the deflagration effect under simulated different working conditions is accurately evaluated. At the same time, the external shell is a combustible shell, and there is little residual residue after combustion, which ensures the cleanliness of the wellbore.

[0057] To sum up, in this embodiment, high and low burning rate propellant agents are cast in sequence to form a gradual burning rate propulsion system, and the combustion method is layer-by-layer combustion. After the low burning rate burns for a certain period of time, the high burning rate starts to burn to increase the wellbore pressure. After the combustion is stable, the low burning rate starts to burn. The high burning rate increases the pressure quickly, which is beneficial to the formation fracturing. The subsequent low burning rate forms a long-term combustion, which is beneficial to the extension of the formation cracks. The high and low burning rates burn alternately, and multiple pulsed pressure fluctuations are formed after combustion, which can not only increase the combustion time and improve the seam extension effect, but also improve the combustion reliability. At the same time, the outer shell of the pulsed deflagration column is a combustible shell, and the gas release nozzle is designed as a truncated cone structure, which is not only conducive to increasing the combustion power of the column and reducing the vibration of the pipe column, but also there is little residual residue in the shell after combustion, which ensures the cleanliness of the wellbore.

[0058] Embodiment 2:

[0059] This embodiment provides a performance test method for a long combustion pulse clean type deflagration system and a performance test method, which is used to perform a combustion performance test on the above-mentioned long combustion pulse clean type deflagration system and a performance test method, and includes the following steps:

[0060] S1. First, the pulse deflagration charge assembly 1 is threadedly connected to the ignition plug 5, and then the pressure cap 6 and the sealing conductive pin 7 are installed in the ignition plug 5;

[0061] S2. The sealed conductive pin 7 mounted on the ignition plug 5 is installed in the inner hole of the pulse deflagration charge, and the sealed conductive pin 7 is connected to the electric heater 104 through a quick plug wire 105;

[0062] S3. The sleeve 201 joint is threadedly connected to the sleeve 201 of the test target 2, and the pressure joint 3 is further threadedly connected to the sleeve 201 joint, and the pressure pipeline and the pressure device are connected to the sleeve 201 to pressurize 10MPa, and the sealed conductive pin 7 is connected to the plug wire, and the ignition is successful in about 15s by passing 110V DC;

[0063] S4. Finally, the combustion performance is reflected by testing the length, width and number of cracks formed in the rock pores of target 2.

[0064] The specific test method is as follows:

[0065] (1) Different MPa pressures are applied to the test target 2 through the pressure joint 3, and the length, width and number of cracks formed in the pores of the same rock layer 202 are observed and measured after the pulse deflagration charge assembly 1 with the same charge amount is burned;

[0066] (2) Under the same pressure environment, after the pulse deflagration charge assembly 1 with different charge amounts is burned, the length, width and number of cracks formed in the pores of the same rock layer 202 are observed and measured;

[0067] (3) Under the same pressure environment, after the pulse deflagration charge assembly 1 with the same charge amount is burned, the length, width and number of cracks formed in the pores of the same rock layer 202 with different strengths are observed and measured;

[0068] (4) Under the same pressure environment, after the pulse deflagration charge assembly 1 with the same charge amount is burned, the length, width and number of cracks formed in the pores of different types of rock layers 202 with the same strength are observed and measured.

[0069] In summary, compared with the existing ground test of deflagration fracturing combustion performance which mainly adopts the method of testing the deflagration effect by generating high-energy gas by deflagration at normal temperature and pressure to crack concrete targets, this embodiment uses rocks with the same physical property parameters as the downhole formation to manufacture target targets, and prefabricates perforation channels of the same size in advance to establish a downhole deflagration test under wellbore pressure, which can more accurately test the rock cracking and seam extension effects.

[0070] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0071] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. When an element is referred to as being "assembled on", "installed on", "fixed on" or "set on" another element, it can be directly on the other element or there can also be a centered element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be a centered element at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and are not intended to be the only implementation method.

[0072] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0073] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

Claims

1. A long combustion pulse clean deflagration system and performance test method, comprising a test target (2), characterized in that: A sleeve (201) is installed inside the test target (2), the top of the sleeve (201) is threadedly connected to a sleeve (201) joint, the center of the sleeve (201) joint is threadedly connected to a pulse deflagration charge column assembly (1), the middle of the pulse deflagration charge column assembly (1) is threadedly connected to an ignition plug (5), a sealed conductive pin (7) is installed inside the ignition plug (5), a pressure cap (6) is coaxially installed above the sealed conductive pin (7), and the pressure cap (6) is threadedly connected to the ignition plug (5), the sealed conductive pin (7) is connected to the pulse deflagration charge column assembly (1) for igniting the pulse deflagration charge column assembly (1), and when the pulse deflagration charge column assembly (1) burns, high and low burning rates are alternately burned to form high-temperature and high-pressure gas to act on the test target (2); The top of the sleeve (201) joint is threadedly connected to a pressure joint (3), and the pressure joint (3) is located on one side of the ignition plug (5).

2. A long combustion pulse clean deflagration system and performance testing method according to claim 1, characterized in that: The test target (2) comprises a rock layer (202) built on the outside of a casing (201); the rock layer (202) and the casing (201) are gap-matched, the gap is no greater than 2 mm, and is filled with concrete; a concrete layer (203) is cast on the outside of the rock layer (202), and a target sleeve (204) is sleeved on the outer surface of the concrete layer (203); The side wall of the casing (201) is provided with a plurality of through holes 1 in the radial direction, and the side wall of the rock layer (202) is provided with through holes 2 in the radial direction at positions corresponding to the through holes 1 on the casing (201), and the outer end of the through holes 2 is sealed by concrete.

3. A long combustion pulse clean deflagration system and performance testing method according to claim 2, characterized in that: The pulse deflagration charge assembly (1) is located in a sleeve (201), and the space between the pulse deflagration charge assembly (1) and the sleeve (201) is filled with clean water. The pulse deflagration charge assembly (1) comprises a combustible shell (101) threadedly connected to a joint of the sleeve (201), and a plurality of high-burning-rate charge columns (103) and low-burning-rate charge columns (102) are cast from bottom to top inside the combustible shell (101), and the high-burning-rate charge columns (103) and the low-burning-rate charge columns (102) are cast alternately in sequence.

4. A long combustion pulse clean deflagration system and performance testing method according to claim 3, characterized in that: The top of the combustible shell (101) is provided with a truncated cone-shaped inner cavity, the cone angle of the truncated cone inner cavity is set to 0°-120°, the depth is greater than 3 mm, and a sealing ring (8) is provided between the top of the combustible shell (101) and the joint of the sleeve (201).

5. A long combustion pulse clean deflagration system and performance testing method according to claim 4, characterized in that: An electric heater (104) is installed at the bottom end of the combustible shell (101), and the electric heater (104) is installed in the high-burning-rate powder column (103) at the bottom layer. A quick plug wire (105) is connected to the top end of the electric heater (104), and the top end of the quick plug wire (105) is connected to the sealed conductive pin (7).

6. A long combustion pulse clean deflagration system and performance testing method according to claim 5, characterized in that: Sealing rings (8) are provided between the sleeve (201) and the sleeve joint (4), and between the combustible shell (101) and the ignition plug (5).

7. A long combustion pulse clean deflagration system and performance testing method according to claim 5, characterized in that: The combustible shell (101) is made of aluminum alloy, the outer diameter of the combustible shell (101) is set to 30 mm-178 mm, and the wall thickness is not less than 5 mm.

8. A long combustion pulse clean deflagration system and performance testing method according to claim 7, characterized in that: The thickness of the low burning rate powder column (102) and the high burning rate powder column (103) are both greater than 50 mm. The low burning rate powder column (102) and the high burning rate powder column (103) are both made of ammonium perchlorate, terminal hydroxyl polybutadiene and aluminum powder. The burning rate of the low burning rate powder column (102) is 1 mm / s-5 mm / s, and the burning rate of the high burning rate powder column (103) is 8 mm / s-12 mm / s.

9. A long combustion pulse clean deflagration system and performance testing method according to claim 8, characterized in that: The sleeve (201) is configured as a round tube, the outer diameter of the round tube is greater than 60 mm, the height of the round tube is configured to be 300 mm-1800 mm, the bottom of the round tube is closed, and the top is configured to be open.

10. A performance test method for a long combustion pulse clean deflagration system and a performance test method, used for performing a combustion performance test on a long combustion pulse clean deflagration system and a performance test method as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: S1. First, the pulse deflagration charge assembly (1) is threadedly connected to the ignition plug (5), and then the pressure cap (6) and the sealing conductive pin (7) are installed in the ignition plug (5); S2. The sealed conductive pin (7) mounted on the ignition plug (5) is installed in the inner hole of the pulse deflagration charge, and the sealed conductive pin (7) is connected to the electric heater (104) through a quick plug wire (105); S3. The sleeve (201) joint is threadedly connected to the sleeve (201) of the test target (2), and the pressure joint (3) is further threadedly connected to the sleeve (201) joint, and the pressure pipeline and the pressure device are connected to the sleeve (201) to pressurize, and the sealed conductive pin (7) is connected to the plug wire, and a direct current of 110V is passed to ignite successfully in about 15s; S4. Finally, the combustion performance is reflected by testing the length, width and number of cracks formed in the rock pores of the target (2).

Images