Method for forming complex crack network by utilizing multistage fire blast of chemical hydrogen generation

Abstract

The invention provides a method for forming a complex crack network by utilizing chemical hydrogen generation multi-stage burning explosion. The method comprises the following steps: (1) preparing gas generation particles; (2) an electric spark device is assembled, and an underground electric spark module of the electric spark device is hung on the second drillable bridge plug; (3) putting a first drillable bridge plug into the rear end of the appointed position of the pre-drilled vertical shaft; (4) gas production particles are put into a designated position in the vertical shaft, and then water is injected; (5) putting a second drillable bridge plug into the front end of the appointed position of the vertical shaft; (6) igniting by using an electric spark device; (7) drilling off the first drillable bridge plug and the second drillable bridge plug by using a drill bit; (8) repeating the steps (3)-(7) in a pre-drilled horizontal shaft; and (9) standing until the mixture of hydrogen and oxygen in the reservoir is fully detonated, and forming a new fracture network in the reservoir. By means of the method, more branch fractures can be made, the reservoir diversion effect is enhanced, the diversion capacity is improved, the reservoir recovery rate is effectively increased, and the method is suitable for being used in low-permeability reservoirs.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas reservoir engineering, and in particular to a method for forming a complex fracture network by utilizing chemical hydrogen generation multi-stage explosion. Background Art

[0002] At present, the main method for unconventional reservoir fracture network fracturing is the dense-cut hydraulic fracturing technology. The fracturing fluid used is added with chemical reagents such as viscosity enhancers, drag reducers, and surfactants. The fracturing fluid will also form a large amount of flocculent sediments when it breaks and flows back, which is extremely harmful to the reservoir and seriously hinders the migration of oil and gas. On the other hand, there are many problems in the production of hydrogen by electrolysis of water:

[0003] (1) The ratio of hydrogen and oxygen produced by water electrolysis is fixed, and the application conditions are limited;

[0004] (2) The safety factor of the water electrolysis process in the wellbore is very low, and accidents are prone to go out of control;

[0005] (3) The electrolysis of water is limited by the conditions and the location where it occurs, and cannot be applied to multi-stage explosions in reservoirs.

[0006] To sum up, it is necessary to make further innovations on existing technologies. Summary of the invention

[0007] In response to the technical problems existing in the above-mentioned background technology, the present invention proposes a method for forming a complex fracture network by multi-stage explosion of chemical hydrogen production. Gas-producing particles are injected into the reservoir. The hydrogen-oxygen mixture releases extremely high pressure at the moment of detonation, which can quickly form and expand cracks in the formation, forming a new fracture network, thereby increasing the permeability of the reservoir and the oil and gas flow channels, solving the problems faced by traditional hydraulic fracturing technology and improving oil and gas recovery rates.

[0008] In order to solve the above technical problems, the present invention provides a method for forming a complex crack network by using chemical hydrogen generation multi-stage explosion, which comprises the following steps:

[0009] (1) Preparation of gas-generating particles

[0010] The gas-producing particles prepared on the ground in advance are placed in the reservoir to react with the water in the reservoir to generate a mixture of hydrogen and oxygen;

[0011] (2) assembling an electric spark device, wherein the electric spark device is divided into a ground electric spark module and a downhole electric spark module, and hanging the downhole electric spark module of the electric spark device on the second drillable bridge plug;

[0012] (3) placing a first drillable bridge plug into the rear end of a designated position of a pre-drilled vertical wellbore;

[0013] (4) placing the prepared gas-producing particles into a designated position in the vertical wellbore and then injecting water;

[0014] (5) placing a second drillable bridge plug into the front end of the designated position of the vertical wellbore;

[0015] (6) Ignition using an electric spark device;

[0016] (7) after a sufficient time has passed to allow the mixture of hydrogen and oxygen to be fully detonated, drilling out the first drillable bridge plug and the second drillable bridge plug using a drill bit;

[0017] (8) placing a first drillable bridge plug at the rear end of a designated position in a pre-drilled horizontal wellbore, placing gas-producing particles, and then injecting water, and then placing a second drillable bridge plug with an electric spark device at the front end of the designated position, waiting for the gas-producing particles to react with water to generate hydrogen and oxygen, sending an ignition command, and after a sufficient time for the hydrogen and oxygen mixture to fully explode, using a drill bit to drill out the first drillable bridge plug and the second drillable bridge plug;

[0018] (9) Wait for the hydrogen and oxygen mixture in the reservoir to be fully detonated, eventually forming a new fracture network in the reservoir.

[0019] The method of forming a complex crack network by multi-stage explosion of chemical hydrogen generation, wherein the gas-producing raw material is composed of solid particles in the following mass percentages: 55%-60% sodium peroxide particles, 35%-40% pure aluminum, 3%-4% magnesium powder, and the rest is silicon powder.

[0020] The method of forming a complex crack network by multi-stage explosion of chemical hydrogen generation, wherein the specific process of preparing the gas-generating particles in step (1) is: melting the pure aluminum at a high temperature of 660°C-670°C for 10-20 minutes, adding the magnesium powder and silicon powder and uniformly mixing to obtain a mixture, applying the mixture to the outer layer of the sodium oxide particles, and after completely cooling to a solid, using a water-soluble shell to wrap the solid, the total particle size range of the gas-generating particles is 3mm-5mm, and the compressive strength of the gas-generating particles is 8MPa-12Mpa, thereby obtaining the gas-generating particles.

[0021] The method of forming a complex crack network by multi-stage explosion of chemical hydrogen generation, wherein the volume ratio of the water-soluble shell to the solid matter is 1:1.

[0022] The method of forming a complex crack network by multi-stage explosion of chemical hydrogen generation, wherein: the surface spark module in step (2) includes a high voltage power supply, a control unit, a remote controller, a data transmission module and a surface sensor, and the downhole spark module includes an ignition rod, an ignition coil and a spark plug;

[0023] The electric spark device in step (2) is assembled as follows: the high-voltage power supply is electrically connected to the control unit, and the control unit is electrically connected to the remote controller, the data transmission module, the ground sensor and the ignition rod respectively; the ignition rod is electrically connected to the ignition coil, and the ignition coil is electrically connected to the spark plug; the ignition rod, the ignition coil and the spark plug are hung on the second drillable bridge plug.

[0024] The method of forming a complex fracture network by multi-stage explosion of chemical hydrogen generation, wherein: in step (3), the first drillable bridge plug is lowered into the rear end of a designated position in the wellbore through a continuous oil pipe.

[0025] The method of using chemical hydrogen generation multi-stage explosion to form a complex fracture network, wherein: in the step (4), the prepared gas-generating particles are placed through a continuous oil pipe; and the ratio of the total volume of the gas-generating particles to the volume of the injected water is 1:8, and the water-soluble shell on the surface of the gas-generating particles is waited to dissolve in the water, and the exposed soluble aluminum alloy and sodium peroxide then react with water to generate hydrogen and oxygen.

[0026] The method of forming a complex fracture network by multi-stage explosion of chemical hydrogen generation, wherein: the step (5) is to place a second drillable bridge plug into the front end of a designated position in the vertical wellbore through a continuous oil pipe.

[0027] The method of using chemical hydrogen generation multi-stage explosion to form a complex fracture network, wherein the specific process of step (6) is: an operator sends an ignition command to the control unit through a ground remote controller, and after the control unit recognizes the command, it transmits the command to the ignition rod in the vertical wellbore through the data transmission module. After receiving the command, the ignition rod activates the ignition coil, and the ignition coil generates an electric spark after generating a sufficient voltage difference, and the environmental parameters during the ignition process are monitored by the ground sensor.

[0028] The method of forming a complex fracture network by multi-stage explosion of chemical hydrogen generation, wherein the step (9) is to wait for 5-7 hours to ensure that the hydrogen-oxygen mixture in the reservoir is fully detonated.

[0029] By adopting the above technical solution, the present invention has the following beneficial effects:

[0030] The method of forming a complex fracture network by multi-stage explosion of chemical hydrogenation is reasonably conceived. The water formed by hydrogen explosion does not harm the reservoir. The process is environmentally friendly. The solid particle chemical hydrogenation process is introduced to realize artificial control of the gas production ratio and the gas production speed, thereby ensuring the flexibility of application scenarios. Multi-stage explosion fracturing can be realized to form a more complex fracture network system.

[0031] The present invention injects gas-producing particles into the reservoir. The hydrogen-oxygen mixture releases extremely high pressure at the moment of detonation, which can quickly form and expand cracks in the formation and form a new crack network, thereby increasing the permeability of the reservoir and the oil and gas flow channels, solving the problems faced by traditional hydraulic fracturing technology and improving oil and gas recovery rates.

[0032] The present invention can create more branch fractures, enhance the reservoir diversion effect, improve the diversion capacity, effectively increase the reservoir recovery rate, and is suitable for use in low permeability reservoirs.

[0033] The present invention also has the following characteristics and advantages:

[0034] (1) The control unit of the electric spark device can control the timing of ignition to avoid premature or late detonation, which is more flexible;

[0035] (2) The choice of a water-soluble shell on the particle surface can control the time when the internal aluminum alloy and sodium peroxide begin to react with water;

[0036] (3) Based on the volume of water injected, the chemical equations for the reaction of aluminum powder and water to generate hydrogen, and the reaction of sodium peroxide and water to generate oxygen (2Al+6H2O→2Al(OH)3+3H2, 2Na2O2+2H2O→4NaOH+O2), the ratio of hydrogen and oxygen generated can be inferred, and the ratio of the mixed gas can be controlled;

[0037] (4) Compared with traditional hydraulic fracturing, hydrogen detonation reduces the impact on groundwater and the environment to a certain extent, while reducing the use of water resources;

[0038] (5) Compared with hydraulic fracturing, the process of hydrogen explosion to form a fracture network can more quickly increase the bottom permeability and form a complex fracture network structure, thereby accelerating the flow of oil and gas and the speed of production.

[0039] (6) By adjusting the position of the drillable bridge plug and controlling the hydrogen and oxygen generation ratio, the location and size of the fractures can be regulated to improve the mining effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 A flow chart of the method of forming a complex crack network by multi-stage explosion of chemical hydrogen generation according to the present invention;

[0042] Figure 2A schematic diagram of gas-producing particles in a vertical wellbore and injected water not reacting in a reservoir involved in the method of forming a complex fracture network by multi-stage explosion of chemical hydrogen generation according to the present invention;

[0043] Figure 3 It is a schematic diagram of the method of forming a complex fracture network by multi-stage explosion of chemical hydrogen generation in the present invention, in which the gas-producing particles in the vertical wellbore and the injected water have partially reacted in the reservoir to produce hydrogen and oxygen;

[0044] Figure 4 A schematic diagram of the method of forming a complex fracture network by multi-stage explosion of chemical hydrogen generation in the present invention, in which hydrogen and oxygen in a vertical wellbore are completely detonated and fractures in a reservoir are formed;

[0045] Figure 5 A schematic diagram of gas-producing particles in a horizontal wellbore and injected water not reacting in a reservoir involved in the method of forming a complex fracture network by multi-stage explosion of chemical hydrogen generation according to the present invention;

[0046] Figure 6 It is a schematic diagram of the method of forming a complex fracture network by multi-stage explosion of chemical hydrogen generation in the present invention, in which gas-producing particles in a horizontal wellbore and injected water have partially reacted in the reservoir to produce hydrogen and oxygen;

[0047] Figure 7 This is a schematic diagram of the formation of fractures in the reservoir in which hydrogen and oxygen in the horizontal wellbore are completely detonated in the method of forming a complex fracture network by multi-stage explosion of chemical hydrogen generation according to the present invention.

[0048] Notes:

[0049] 1-vertical wellbore, 2-first drillable bridge plug, 3-gas-producing particles, 4-injected water, 5-second drillable bridge plug, 6-electric spark device, 7-hydrogen, 8-oxygen, 9-new fracture network, 10-horizontal wellbore. DETAILED DESCRIPTION

[0050] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] The present invention is further explained below in conjunction with specific implementation modes.

[0052] like Figure 1 As shown, this embodiment provides a method for forming a complex crack network by using chemical hydrogen generation multi-stage explosion, comprising the following steps:

[0053] S001. Preparation of gas-generating particles 3

[0054] The gas-generating particles 3 prepared on the ground in advance are placed in the reservoir to react with the water in the reservoir to generate a mixture of hydrogen 7 and oxygen 8. The process is as follows: Figure 2 As shown, pure aluminum is melted at a high temperature of 660°C-670°C, magnesium powder and silicon powder are added and evenly mixed to obtain a mixture A, and the mixture A is applied to the outer layer of sodium peroxide particles. After being completely cooled to a solid B, the solid B is wrapped with a water-soluble shell to obtain gas-generating particles 3 (as shown in FIG. Figure 3 As shown). The raw materials include sodium peroxide, aluminum, magnesium, silicon, and a water-soluble shell; in the solid particles, by mass percentage, 55%-60% sodium peroxide, 35%-40% aluminum, 3%-4% magnesium, and the rest is silicon; the volume ratio of the water-soluble shell to the solid particles is 1:1, and the total particle size of the gas-generating particles 3 is 3mm-5mm. In the preparation process of the gas-generating particles 3, pure aluminum is melted at a high temperature of 660-670°C, and the melting time is 10-20min. Magnesium powder and silicon powder are added and mixed evenly. When the temperature of the mixture drops to 600°C, it is applied to the surface of sodium peroxide, and finally wrapped with a water-soluble shell. The total particle size of the gas-generating particles 3 is in the range of 3mm-5mm, and the compressive strength of the gas-generating particles 3 is 8MPa-12Mpa. Thus, the gas-generating particles 3 are obtained.

[0055] S002, assembly of electric spark device 6

[0056] Assemble the electric spark device 6, which is divided into a ground electric spark module and a downhole electric spark module, and hang the downhole electric spark module of the electric spark device 6 on the second drillable bridge plug 5; the electric spark device 6 includes a high-voltage power supply, a control unit, a remote controller, a data transmission module, a ground sensor, an ignition rod, an ignition coil and a spark plug;

[0057] The connection sequence of the electric spark device 6 is: high voltage power supply → control unit → remote controller, data transmission module, ground sensor, ignition rod, ignition rod → ignition coil → spark plug, reservoir sensor → data transmission module. The underground module ignition rod, ignition coil and spark plug are hung on the drillable bridge plug 2.

[0058] S003, lowering a first drillable bridge plug 2 into the rear end of a designated position of a pre-drilled vertical wellbore 1 through a coiled tubing.

[0059] S004, placing the prepared gas-producing particles 3 into a designated position in the vertical wellbore 1, and then injecting water 4;

[0060] Specifically, the prepared gas-generating particles 3 are placed through a coiled tubing, and then water 4 is injected; wherein the volume ratio of the total volume of the gas-generating particles 3 to the injected water 4 is 1:8, and the water-soluble shell on the surface of the gas-generating particles 3 is waited to dissolve in the injected water 4, and the exposed soluble aluminum alloy and sodium peroxide then react with the injected water 4 to generate hydrogen 7 and oxygen 8 (such as Figure 3 shown).

[0061] S005. Place a second drillable bridge plug 5 into the front end of a designated position in the vertical wellbore 1 through the coiled tubing.

[0062] S006. Ignition is performed using the electric spark device 6. The specific process is as follows: the operator sends an ignition command through the ground remote control. After the control unit recognizes the signal, it transmits the command to the ignition rod in the vertical wellbore 1 through the data transmission module. After receiving the command, the ignition rod activates the ignition coil. The ignition coil generates a sufficient voltage difference to cause the spark plug to generate an electric spark. The ground sensor can monitor the environmental parameters during the ignition process.

[0063] S007, after a sufficient period of time, the mixture is fully detonated (such as Figure 4 As shown), the first drillable bridge plug 2 and the second drillable bridge plug 5 are drilled out using a drill bit.

[0064] S008, repeat the above steps S003-S007 at the designated position in the horizontal wellbore 10. Figure 5-6 The specific process is: first, place the first drillable bridge plug 2 into the rear end of the designated position in the horizontal wellbore 10, place the gas-producing particles 3, then inject water 4, and then place the second drillable bridge plug 5 with an electric spark device 6 into the front end of the designated position, wait for the gas-producing particles 3 to react with the injected water 4 to completely generate hydrogen 7 and oxygen 8, send an ignition command, wait for a long enough time for the mixture of hydrogen 7 and oxygen 8 to fully explode, and then use a drill bit to drill out the first drillable bridge plug 2 and the second drillable bridge plug 5 to achieve multi-stage combustion and explosion of the reservoir.

[0065] S009: Wait for the mixture of hydrogen 7 and oxygen 8 in the reservoir to be fully detonated (such as Figure 7 As shown), a new fracture network 9 is eventually formed in the reservoir; as the oil production increases significantly during the oil production process, it is shown that the method of forming a complex fracture network 9 by hydrogen explosion is realized; specifically, waiting for 5-7 hours is required to ensure that the hydrogen-oxygen mixture in the reservoir is fully detonated.

[0066] The technical principle of the present invention is: the sodium peroxide and aluminum alloy wrapped in the prepared gas-producing particles 3 can both react chemically with the injected water 4, and the soluble shell on the surface of the particles ensures the stability of the particles during transportation. The first drillable bridge plug 2 and the second drillable bridge plug 5 are used to construct a closed area at a designated position in the wellbore. When the water-soluble shell on the surface of the gas-producing particles 3 dissolves in the injected water 4, the internal aluminum alloy is exposed and begins to react with the injected water 4 to generate hydrogen 7. As the aluminum alloy reacts completely, the sodium peroxide wrapped therein begins to contact the injected water 4 and reacts with it to produce oxygen 8. At this time, a potentially explosive hydrogen-oxygen mixed gas environment is formed in the closed area. When the operator sends an instruction to the electric spark ignition module located underground through the surface control unit, spark discharge is triggered, resulting in a controlled explosion of the hydrogen-oxygen mixed gas in the closed space. The high pressure and high temperature generated at the moment of the reaction work together to promote the formation and development of new cracks, thereby achieving the purpose of the present invention.

[0067] Monitoring revealed that after the intralayer explosion was achieved by detonating hydrogen 7, a relatively complex fracture network system was formed in the reservoir, providing more seepage channels for the oil and gas in the formation and improving the oil and gas recovery rate.

[0068] Example 1

[0069] A method for forming a complex crack network 9 by using chemical hydrogen generation multi-stage explosion according to embodiment 1 of the present invention comprises the following steps:

[0070] S101, prepare gas-generating particles 3, that is, prepare 35% pure aluminum, 3% magnesium powder, 4% silicon powder, and 58% sodium peroxide. Melt pure aluminum at 660°C for 15 minutes, add magnesium powder and silicon powder and mix them evenly, and then apply mixture A on the surface of sodium peroxide when the temperature drops to 600°C. After it is completely cooled to solid B, wrap the surface of B with a polyvinyl alcohol shell, and the volume ratio of the polyvinyl alcohol shell to the solid particles is 1:1, so as to obtain gas-generating particles 3 with a particle size range of 3 mm.

[0071] S102, assemble the electric spark device 6, and the connection order is: high voltage power supply → control unit → remote control, data transmission module, ground sensor, ignition rod, ignition rod → ignition coil → spark plug, reservoir sensor → data transmission module. Hang the underground module ignition rod, ignition coil and spark plug on the second drillable bridge plug 5.

[0072] S103, placing the first drillable bridge plug 2 into the pre-drilled vertical wellbore 1 at the rear end of the designated position through the coiled tubing.

[0073] S104, gas-producing particles 3 are lowered into a designated position in the vertical wellbore 1 through a coiled tubing, and then water 4 is injected, with the total volume of the particles and the volume of the injected water 4 being 1:8.

[0074] S105 , placing the second drillable bridge plug 5 into the vertical wellbore 1 at the front end of the designated position through the coiled tubing.

[0075] S106, sending an ignition command through the remote controller of the electric spark device 6, the control unit of the electric spark device 6 recognizes the signal and transmits it to the ignition rod of the vertical wellbore 1 through the data transmission module, and the ignition rod activates the ignition coil after receiving the command, and the ignition coil generates enough voltage difference to make the spark plug generate electric spark.

[0076] S107, after the explosion in the reservoir, use a drill bit to drill out the first drillable bridge plug 2 and the second drillable bridge plug 5;

[0077] S108 . Repeat the above steps S103 to S107 in the pre-drilled horizontal wellbore 10 .

[0078] S109, waiting for about 5 hours to ensure that the mixture of hydrogen 7 and oxygen 8 in the reservoir is fully detonated and a new fracture network 9 is formed in the reservoir.

[0079] Monitoring revealed that after the intralayer explosion was achieved by detonating hydrogen 7, a relatively complex fracture network system was formed in the reservoir, providing more seepage channels for the oil and gas in the formation and improving the oil and gas recovery rate.

[0080] Example 2

[0081] A method for forming a complex crack network 9 by using chemical hydrogen generation multi-stage explosion according to embodiment 2 of the present invention comprises the following steps:

[0082] S201, prepare gas-generating particles 3, that is, prepare 38% pure aluminum, 2% magnesium powder, 3% silicon powder, and 57% sodium peroxide. Melt pure aluminum at 670°C for 10 minutes, add magnesium powder and silicon powder and mix them evenly, and then apply the mixture A on the surface of sodium peroxide when the temperature drops to 600°C. After it is completely cooled to a solid B, wrap the surface of B with a polyethylene glycol shell, and the volume ratio of the polyethylene glycol shell to the solid particles is 1:1. After applying evenly, gas-generating particles 3 with a particle size range of 5 mm are obtained.

[0083] S202, assemble the electric spark device 6, the connection sequence of the electric spark device 6 is: high voltage power supply → control unit → remote controller, data transmission module, ground sensor, ignition rod, ignition rod → ignition coil → spark plug, reservoir sensor → data transmission module. Hang the underground module ignition rod, ignition coil and spark plug on the second drillable bridge plug 5.

[0084] S203, placing the first drillable bridge plug 2 into the pre-drilled vertical wellbore 1 at the rear end of the designated position through the coiled tubing.

[0085] S204, lowering gas-producing particles 3 into a designated position in the vertical wellbore 1 through a coiled tubing, and then injecting water 4, with the total volume of the particles and the volume of the injected water 4 being 1:8.

[0086] S205, placing the second drillable bridge plug 5 into the vertical wellbore 1 at the front end of the designated position through the coiled tubing.

[0087] S206, sending an ignition command through the remote controller, the control unit recognizes the signal and transmits it to the ignition rod in the vertical shaft 1 through the data transmission module, the ignition rod activates the ignition coil after receiving the command, and the ignition coil generates enough voltage difference to make the spark plug generate electric spark.

[0088] S207 . After the explosion in the reservoir, the first drillable bridge plug 2 and the second drillable bridge plug 5 are drilled out using a drill bit.

[0089] S208 . Repeat the above steps S203 to S207 in the pre-drilled horizontal wellbore 10 .

[0090] S209, waiting for about 7 hours to ensure that the hydrogen-oxygen mixture in the reservoir is fully detonated and a new fracture network 9 is formed in the reservoir, as shown in S9 in the attached figure.

[0091] Monitoring revealed that after the intralayer explosion was achieved by detonating hydrogen 7, a relatively complex fracture network system was formed in the reservoir, which increased the seepage channels of oil and gas in the formation and improved the oil and gas recovery rate.

[0092] The present invention injects gas-producing particles into the reservoir. The hydrogen-oxygen mixture releases extremely high pressure at the moment of detonation, which can quickly form and expand cracks in the formation and form a new crack network, thereby increasing the permeability of the reservoir and the oil and gas flow channels, solving the problems faced by traditional hydraulic fracturing technology and improving oil and gas recovery rates.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for forming a complex crack network by multi-stage explosion of chemical hydrogen generation, characterized in that: The following steps are involved: (1) Preparation of gas-generating particles The gas-producing particles prepared on the ground in advance are placed in the reservoir to react with the water in the reservoir to generate a mixture of hydrogen and oxygen; (2) assembling an electric spark device, wherein the electric spark device is divided into a ground electric spark module and a downhole electric spark module, and hanging the downhole electric spark module of the electric spark device on the second drillable bridge plug; (3) placing a first drillable bridge plug into the rear end of a designated position of a pre-drilled vertical wellbore; (4) placing the prepared gas-producing particles into a designated position in the vertical wellbore and then injecting water; (5) placing a second drillable bridge plug into the front end of the designated position of the vertical wellbore; (6) Ignition using an electric spark device; (7) after a sufficient time has passed to allow the mixture of hydrogen and oxygen to be fully detonated, drilling out the first drillable bridge plug and the second drillable bridge plug using a drill bit; (8) placing a first drillable bridge plug at the rear end of a designated position in a pre-drilled horizontal wellbore, placing gas-producing particles, and then injecting water, and then placing a second drillable bridge plug with an electric spark device at the front end of the designated position, waiting for the gas-producing particles to react with water to generate hydrogen and oxygen, sending an ignition command, and after a sufficient time for the hydrogen and oxygen mixture to fully explode, using a drill bit to drill out the first drillable bridge plug and the second drillable bridge plug; (9) Wait for the hydrogen and oxygen mixture in the reservoir to be fully detonated, eventually forming a new fracture network in the reservoir.

2. The method for forming a complex crack network by multi-stage explosion of chemical hydrogen generation as claimed in claim 1, characterized in that: The gas production raw material is composed of solid particles in the following mass percentages: 55%-60% of sodium peroxide particles, 35%-40% of pure aluminum, 3%-4% of magnesium powder, and the rest is silicon powder.

3. The method for forming a complex crack network by multi-stage explosion of chemical hydrogen generation as claimed in claim 2, characterized in that: The specific process of preparing the gas-generating particles in the step (1) is as follows: the pure aluminum is melted at a high temperature of 660° C.-670° C. for 10-20 minutes, the magnesium powder and the silicon powder are added and uniformly mixed to obtain a mixture, the mixture is applied to the outer layer of the sodium oxide particles, and after the mixture is completely cooled to a solid state, the solid state is wrapped with a water-soluble shell. The total particle size of the gas-generating particles is in the range of 3 mm-5 mm, and the compressive strength of the gas-generating particles is 8 MPa-12 MPa, thereby obtaining the gas-generating particles.

4. The method for forming a complex crack network by multi-stage explosion of chemical hydrogen generation as claimed in claim 3, characterized in that: The volume ratio of the water-soluble shell to the solid matter is 1:

1.

5. The method for forming a complex crack network by multi-stage explosion of chemical hydrogen generation as claimed in claim 1, characterized in that: The surface spark module in step (2) includes a high voltage power supply, a control unit, a remote controller, a data transmission module and a surface sensor, and the downhole spark module includes an ignition rod, an ignition coil and a spark plug; The electric spark device in step (2) is assembled as follows: the high-voltage power supply is electrically connected to the control unit, and the control unit is electrically connected to the remote controller, the data transmission module, the ground sensor and the ignition rod respectively; the ignition rod is electrically connected to the ignition coil, and the ignition coil is electrically connected to the spark plug; the ignition rod, the ignition coil and the spark plug are hung on the second drillable bridge plug.

6. The method for forming a complex crack network by multi-stage explosion of chemical hydrogen generation as claimed in claim 1, characterized in that: In the step (3), the first drillable bridge plug is lowered into the rear end of a designated position in the wellbore through a continuous oil pipe.

7. The method for forming a complex crack network by multi-stage explosion of chemical hydrogen generation as claimed in claim 1, characterized in that: In the step (4), the prepared gas-generating particles are placed through a continuous oil pipe; and the ratio of the total volume of the gas-generating particles to the volume of the injected water is 1:8, and the water-soluble shell on the surface of the gas-generating particles is waited to dissolve in the water, and the exposed soluble aluminum alloy and sodium peroxide then react with water to generate hydrogen and oxygen.

8. The method for forming a complex crack network by multi-stage explosion of chemical hydrogen generation as claimed in claim 1, characterized in that: The step (5) is to place a second drillable bridge plug into the front end of a designated position in the vertical wellbore through a continuous oil pipe.

9. The method for forming a complex crack network by multi-stage explosion of chemical hydrogen generation as claimed in claim 1, characterized in that: The specific process of step (6) is as follows: the operator sends an ignition command to the control unit through the ground remote control. After the control unit recognizes the command, it transmits the command to the ignition rod in the vertical wellbore through the data transmission module. After receiving the command, the ignition rod activates the ignition coil. After the ignition coil generates a sufficient voltage difference, an electric spark is generated. The environmental parameters during the ignition process are monitored by the ground sensor.

10. The method for forming a complex crack network by multi-stage explosion of chemical hydrogen generation as claimed in claim 1, characterized in that: The step (9) is to wait for 5-7 hours to ensure that the hydrogen-oxygen mixture in the reservoir is fully detonated.

Images