A high-energy gas fracturing method and system

Abstract

The application relates to the technical field of oil exploitation, and discloses a high-energy gas fracturing method and system. The method comprises the following steps: lowering a multichannel coiled tubing device into a well shaft, and making an electric shock and explosion device at the tail end of the multichannel coiled tubing device reach a target operation space. Setting a packer on the multichannel coiled tubing device to seal the target operation space from the upper and lower well shafts. Controlling the electric shock and explosion device to generate an electric shock and explosion in the target operation space. Injecting a nanometer metal dispersion liquid and a phase change expansion liquid into the target operation space through the multichannel coiled tubing device. Controlling the nanometer metal dispersion liquid and the phase change expansion liquid to mix in the target operation space to form a high-energy reaction mixture. Controlling the electric shock and explosion device to generate an electric shock and explosion in the high-energy reaction mixture to make the high-energy reaction mixture have a cascade reaction. The application has the effects of greatly saving water and reducing fracturing cost.

Description

Technical Field

[0001] This application relates to the field of oil extraction technology, and proposes a high-energy gas fracturing method and system. Background Technology

[0002] In the development of deep-earth resources such as oil and gas, coalbed methane, and geothermal energy, energy extraction is crucial. With societal development, the demand for energy is increasing, prompting continuous advancements in deep-earth resource development technologies. In the past, hydraulic fracturing was the primary method used to address deep-earth resource development challenges. Hydraulic fracturing is an effective method in the development of deep-earth porous resources. However, it consumes large amounts of water, resulting in high costs. Furthermore, the fracturing efficiency varies under different geological conditions. For example, in situations with poor top and bottom plate stress, poor lithological interlayer properties, or well-developed fracture systems in the target layer, most of the artificially injected fluid remains within the primary fractures, leading to poor fracturing effects.

[0003] Some technologies use phase change expanding liquids instead of water for fracturing. Although phase change expanding liquid fracturing consumes almost no water resources, like hydraulic fracturing, it requires large pressurization equipment to be set up on the ground to apply enormous pressure to the water or phase change expanding liquid. This increases the complexity of the equipment and the cost of fracturing.

[0004] The aforementioned technologies suffer from drawbacks such as high fracturing costs and high water resource requirements. Summary of the Invention

[0005] To reduce fracturing costs and water resource requirements, this application provides a high-energy gas fracturing method and system.

[0006] On the one hand, the high-energy gas fracturing method provided in this application adopts the following technical solution: A high-energy gas fracturing method, comprising: S2. Run the multi-channel coiled tubing into the wellbore and bring the electric detonation device at the end of the multi-channel coiled tubing into the target working space. S3. Operate the setting packer on the multi-channel coiled tubing equipment to separate the target working space from the upper and lower wellbore. S4. Control the electric detonation device to generate an electric detonation in the target work space; S5. Inject nano-metal dispersion and phase change expansion liquid into the target working space through the multi-channel continuous tubing equipment; S6. Control the mixing of the nano-metal dispersion and the phase change expansion liquid in the target working space to form a high-energy reaction mixture; S7. Control the electric detonation device to generate an electric detonation in the high-energy reaction mixture, so that the high-energy reaction mixture undergoes a cascade reaction. S8. Repeat steps S5-S7; wherein the cascade reaction is as follows: the electric detonation generates shock waves and thermal energy in the high-energy reaction mixture; the shock waves and thermal energy generated by the electric detonation cause the nano-metal dispersion to undergo a thermochemical reaction; the heat generated by the thermochemical reaction of the nano-metal dispersion causes the phase change expansion liquid to vaporize.

[0007] By employing the above-mentioned technical solution, a high-frequency shock wave is generated through initial electric shock detonation, inducing micro-fractures in the wellbore and near-wellbore zone, thus reducing formation fracturing pressure. Then, the shock wave and thermal energy generated by the electric shock detonation device trigger a thermochemical reaction between nano-metal particles and water. The thermochemical reaction generates high heat, causing the phase change expansion liquid to vaporize and expand instantaneously, producing a huge pressure pulse and significantly increasing the fracture volume. The nano-metal dispersion and the phase change expansion liquid are mixed only after injection into the target space and fractures, avoiding the risks of premature detonation or high-pressure transport that might occur with surface mixing. Multiple thermochemical reactions and the vaporization of the phase change expansion liquid achieve pulsed loading of the formation. This repeated impact loading can induce fatigue failure in the rock, forming a more complex fracture network structure than a single fracturing operation.

[0008] Optionally, in step S5, the nano-metal dispersion includes nano-metal particles, a thickener, water, and an active agent.

[0009] By adopting the above technical solution, nano-metal powder, as a high-energy fuel, has an extremely high calorific value and can provide a sufficient heat source for the gasification of phase change expansion liquid. Thickeners and activators ensure that the nano-metal particles are uniformly dispersed in the liquid and do not settle, preventing blockage during pumping and ensuring a continuous and uniform reaction effect.

[0010] Optionally, in step S5, an oxide film is formed on the surface of the nano-metal particles.

[0011] By adopting the above technical solution, the oxide film can effectively prevent premature slow oxidation reactions between the nano-metal particles and the water-based carrier during storage and pumping. Only under the shock wave and thermal impact generated by a strong electric shock explosion will the oxide waterproof film on the nano-metal particles rupture, instantly exposing the nano-metal particles and causing a violent reaction, thus achieving precise control of the reaction time.

[0012] Optionally, in step S5, the nano-metal dispersion comprises 0.4-0.5% of the nano-metal particles by mass, 0.15-0.25% of the thickener by mass, 5-8% of the activator by mass, and water.

[0013] By adopting the above technical solution, a reasonable ratio range balances the viscosity of the liquid (facilitating particle carrying) and its flowability (reducing friction and facilitating pumping). A nano-metal particle concentration of 0.4-0.5% by mass of the nano-metal dispersion ensures sufficient heat generation while avoiding cost waste or unreacted residue clogging the formation due to excessive concentration.

[0014] Optionally, in step S5, the volume ratio of the nano-metal dispersion to the phase change expansion liquid is in the range of 1:5 to 1:4.

[0015] By adopting the above technical solution, the volume ratio of the nano-metal dispersion to the phase change expansion liquid ranges from 1:5 to 1:4. This ensures that the heat generated by the metal reaction is just enough to maximize the vaporization of all the phase change liquid, avoiding heat waste or incomplete vaporization of the working fluid, thereby achieving the maximum expansion work efficiency.

[0016] Optionally, in step S4, the target work space contains water for electric shock blasting.

[0017] By adopting the above technical solution, electric detonation can generate plasma channels and shock waves with extremely high energy conversion efficiency by discharging in water, thereby improving the fracturing effect of electric detonation on the surrounding rocks.

[0018] Optionally, the method may also include the following steps before step S2: S1. Perforate all predetermined target working spaces to establish connection channels between the wellbore and each formation.

[0019] By employing the above technical solution, perforations penetrate the casing and cement sheath, reducing the resistance to subsequent fluid entry into the formation. The orientation and depth of the perforation can guide the extension direction of the fracturing fracture, improving fracture control capabilities.

[0020] Optionally, after step S8, the method further includes: S9. Release the setting packer on the multi-channel coiled tubing equipment and lift the multi-channel coiled tubing equipment.

[0021] By adopting the above technical solution, the operation after the single-layer operation is completed is clarified, which facilitates rapid movement to the next layer for operation (drag fracturing) and improves the construction efficiency of multi-layer fracturing.

[0022] On the other hand, this application also discloses a high-energy gas fracturing system using the following technical solution.

[0023] A high-energy gas fracturing system, comprising: A multi-channel coiled tubing system is installed in the wellbore, and the multi-channel coiled tubing system is equipped with an electric detonation device. An electric detonation ground device is connected to the electric detonation device, and the electric detonation ground device is used to control the electric detonation device to generate an electric detonation in the target work space; A phase change expansion liquid pumping device is connected to the multi-channel coiled tubing equipment, and the phase change expansion liquid pumping device is used to pump phase change expansion liquid into the multi-channel coiled tubing equipment. A nano-metal dispersion pumping device is connected to the multi-channel continuous tubing equipment, and the nano-metal dispersion pumping device is used to pump nano-metal dispersion into the multi-channel continuous tubing equipment.

[0024] By adopting the above technical solution, both the phase change expansion liquid and the nano-metal dispersion have their own independent pumping equipment. This allows for the adjustment of the injection rate and ratio of the phase change expansion liquid and the nano-metal dispersion according to the formation conditions, thus achieving precise control of the fracturing process.

[0025] Optionally, the system also includes a packer setting pump, a monitoring device, and a circulation tank. The multi-channel coiled tubing equipment is equipped with a packer setting device, and the packer setting pump is connected to the packer setting device. The multi-channel coiled tubing equipment is equipped with multiple sensors, and the monitoring device is connected to the sensors. The circulation tank is connected to the wellbore via a pipeline and is used to contain wastewater from the wellbore.

[0026] By adopting the above technical solutions, the monitoring equipment can monitor the pressure and vibration data inside the wellbore in real time, helping users to determine the opening status of fractures and the effect of fracturing in the formation, thereby facilitating the adjustment of parameters for the next cycle. The setting packer ensures that fracturing is applied to a specific section, while the circulation tank enables the recycling and treatment of waste liquid, meeting environmental protection requirements and preventing well site pollution.

[0027] In summary, this application includes at least one of the following beneficial technical effects: 1. High-frequency shock waves are generated through initial electric shock detonation, creating micro-fractures in the wellbore and near-wellbore zone, reducing formation fracturing pressure. Then, the shock waves and thermal energy generated by the electric shock detonation device trigger a thermochemical reaction between nano-metal particles and water. The thermochemical reaction generates high heat, causing the phase change expansion liquid to vaporize and expand instantaneously, producing a huge pressure pulse and significantly increasing the fracture volume. The nano-metal dispersion and the phase change expansion liquid are mixed only after injection into the target space and fractures, avoiding the risks of premature detonation or high-pressure transport that might occur with surface mixing. Multiple thermochemical reactions and the vaporization of the phase change expansion liquid achieve pulsed loading of the formation. This repeated impact loading can induce fatigue failure in the rock, forming a more complex fracture network structure than a single fracturing operation. 2. Nano-metal powders, as high-energy fuels, have extremely high calorific value, providing ample heat for the gasification of phase-change expanding liquids. Thickeners and activators ensure that the nano-metal particles are uniformly dispersed in the liquid and do not settle, preventing blockage during pumping and ensuring a continuous and uniform reaction effect. 3. The oxide film effectively prevents premature and slow oxidation reactions between the nano-metal particles and the water-based carrier during storage and pumping. Only under the shock wave and thermal impact generated by a strong electric shock explosion will the oxide film on the nano-metal particles rupture, instantly exposing the nano-metal particles and causing a violent reaction, thus achieving precise control of the reaction time. 4. Both the phase change expansion liquid and the nano-metal dispersion have their own independent pumping equipment, which allows for the adjustment of the injection rate and ratio of the phase change expansion liquid and the nano-metal dispersion according to the formation conditions, thus achieving precise control of the fracturing process. Attached Figure Description

[0028] Figure 1 This is a schematic flowchart of a high-energy gas fracturing method according to an embodiment of this application; Figure 2 This is a schematic diagram of a high-energy gas fracturing system according to an embodiment of this application; Figure 3 This is a cross-sectional view of a multi-channel coiled tubing device of a high-energy gas fracturing system according to an embodiment of this application.

[0029] Explanation of reference numerals in the attached drawings: 10. Multi-channel coiled tubing equipment; 11. Coiled tubing channel; 12. Cable; 13. Rubber coating on multi-channel coiled tubing; 20. Setting packer pumping equipment; 30. Monitoring equipment; 40. Electric detonation ground equipment; 50. Phase change expansion liquid pumping equipment; 60. Nano-metal dispersion pumping equipment; 70. Circulation tank. Detailed Implementation

[0030] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0031] This application discloses a high-energy gas fracturing method.

[0032] Figure 1 This is a schematic flowchart of a high-energy gas fracturing method according to an embodiment of this application. (Refer to...) Figure 1 The high-energy gas fracturing method includes: S1. Perforate all predetermined target working spaces to establish connection channels between the wellbore and each formation.

[0033] S2. Lower the multi-channel coiled tubing equipment 10 into the wellbore and bring the electric detonation device at the end of the multi-channel coiled tubing equipment 10 into the target working space.

[0034] S3. Operate the packer on the multi-channel coiled tubing equipment 10 to separate the target working space from the upper and lower wellbore.

[0035] S4. Control the electric detonation device to generate an electric detonation in the target work space.

[0036] S5. Inject nano-metal dispersion and phase change expansion liquid into the target working space through the multi-channel continuous tubing equipment 10.

[0037] S6. Control the mixing of the nano-metal dispersion and the phase change expansion liquid in the target working space to form a high-energy reaction mixture.

[0038] S7. Control the electric detonation device to generate an electric detonation in the high-energy reaction mixture, so that the high-energy reaction mixture undergoes a cascade reaction.

[0039] S8. Repeat steps S5-S7.

[0040] S9. Release the setting packer on the multi-channel coiled tubing equipment 10 and lift the multi-channel coiled tubing equipment 10.

[0041] The steps described above are explained in detail below.

[0042] In step S1, perforations are made in all predetermined target working spaces to establish connection channels between the wellbore and various formations. Typically, a suitable perforating projectile (the core of the shaped charge perforation, containing high-energy explosive and a specially shaped charge liner) is selected based on parameters such as the rock mechanical properties of the target reservoir, the steel grade and thickness of the casing, and the strength of the cement sheath. The selected perforating projectile is then installed into the perforator according to predetermined perforation density (number of perforations per meter, e.g., 12 perforations / meter), perforation phase (angular distribution of perforations around the wellbore circumference, e.g., 60°, 90°, 120°, etc.), and perforation azimuth (for horizontal wells, directional perforation is required). The perforator can be cable-delivered or tubing-delivered. The assembled perforator is then lowered into the wellbore via cable or tubing.

[0043] Then, depth calibration is performed using logging instruments (such as natural gamma logging) to ensure that the perforating projectile on the perforator is precisely aligned with the predetermined target working space. Once the perforator is precisely positioned, the user sends an electrical signal via cable to detonate the detonator inside the perforator. The detonator detonates the explosive, and the enormous energy generated by the explosion propels and crushes the shaped charge liner. Under the effect of the shaped charge effect, the metal material of the shaped charge liner is plasticized and concentrated into a super-high-speed metal jet with a velocity of 7000-10000 meters per second. This highly concentrated metal jet has extremely strong penetrating power; it instantly penetrates the fluid inside the wellbore, the steel casing, and the cement sheath outside the casing in sequence, and enters and penetrates the target reservoir rock, forming a channel extending from the inside of the wellbore to the depths of the formation, i.e., the perforation channel. After perforation is completed, the perforator is retrieved from the wellbore. At this point, the connection channel between the wellbore and the formations is established.

[0044] In step S2, the multi-channel coiled tubing equipment 10 is lowered into the wellbore, and the electric detonation device at the end of the multi-channel coiled tubing equipment 10 is brought into the target working space.

[0045] First, the electric detonation device is connected to the ends of the first outer and inner tubing. Then, the multi-channel coiled tubing unit 10 is lowered into the wellbore, with the workover rig providing the power for lifting and lowering. During the lowering process, the total length of the lowered multi-channel coiled tubing unit 10 is measured in real time using a depth counter on the drill rig. The user determines the precise depth of the target reservoir based on pre-existing logging data (such as gamma ray and resistivity curves). By comparing the lowering depth of the multi-channel coiled tubing unit 10 with the logging depth, the outlet of the electric detonation device is precisely aligned with the section containing the perforation hole. In this embodiment, the voltage of the electric detonation device is greater than 10KV, and the capacitance is greater than 5000uF.

[0046] In step S3, the packer on the multi-channel coiled tubing unit 10 is set to isolate the target working space from the upper and lower wellbore. Typically, fluid is first pumped downwards from the surface through one channel (e.g., the inner tube) of the multi-channel tubing string. Simultaneously, a temporary plugging device (such as a ball seat for ball setting) is located at the end of the tubing string. The fluid cannot flow out, causing the pressure inside the tubing string to rise rapidly. This increased pressure acts on the hydraulic chamber inside the packer. When the pressure reaches a preset value, it pushes a piston inside the packer. The piston's movement compresses the rubber sealing element wrapped around the packer. Under pressure, the rubber element expands radially outwards and adheres tightly to the well wall (casing inner wall) with a large positive pressure, forming a hydraulic seal. Simultaneously, the piston movement also drives a set of slips. The slips are metal blocks with sharp teeth that are pushed outwards and firmly grip the casing wall, acting as an anchor to prevent the packer from moving under high pressure.

[0047] After setting, the user will pressurize the annulus (the annular space between the multi-channel tubing and the casing) in the upper wellbore to test whether the packer can withstand the pressure without leakage. If the pressure is stable, it proves that the sealed target working space has been successfully established.

[0048] In step S4, the electric detonation device is controlled to generate an electric detonation within the target working space. The target working space contains water for electric detonation. The ground user activates the pulse power system to charge the capacitor bank, raising its voltage to tens of thousands of volts or even higher. Once charging is complete, the user issues a command through the control system, and the enormous electrical energy stored in the capacitor bank is instantaneously applied between the two electrodes downhole via a high-voltage cable in the form of an extremely high current (tens of thousands of amperes) and an extremely short duration (microseconds). The powerful current pulse breaks through the liquid between the two electrodes, creating a plasma channel. The temperature of this channel instantly soars to tens of thousands of degrees Celsius, and the pressure rapidly increases to thousands or even tens of thousands of atmospheres. The high-temperature, high-pressure plasma channel expands outward at an explosive speed, strongly compressing the surrounding liquid, thereby generating an extremely steep hydraulic shock wave with extremely high peak pressure. This spherical or columnar shock wave propagates in the liquid at the speed of sound, violently impacting the rock surface of the target reservoir through the perforation orifice. The enormous stress pulse far exceeds the dynamic tensile strength of the rock, causing it to fracture instantaneously and form a complex initial fracture network radiating outward from the perforation hole. This process may be repeated multiple times in a single operation to produce more complex fractures.

[0049] In step S5, a nano-metal dispersion and a phase change expansion liquid are injected into the target working space through the multi-channel coiled tubing equipment 10. The nano-metal dispersion comprises nano-metal particles, a thickener, water, and an activator. An oxide film is formed on the surface of the nano-metal particles. The nano-metal dispersion comprises 0.4-0.5% of the total mass of the nano-metal particles, 0.15-0.25% of the total mass of the thickener, and 5-8% of the total mass of the activator and water. The volume ratio of the nano-metal dispersion to the phase change expansion liquid is in the range of 1:5 to 1:4. The nano-metal particles can be nano-aluminum metal particles or their nano-alloy particles. The phase change expansion liquid can be liquid carbon dioxide. The thickener can be guar gum, and the activator can be potassium chloride (KCl) or sodium chloride (NaCl).

[0050] To ensure the formation of subsequent cascade reactions, it is necessary to control the combination of nano-metal particles with different particle sizes. A combination of nano-metal particles with sizes ranging from 50nm to 1000nm is mainly used. The smaller-sized nano-metal particles primarily function to lower the trigger temperature of the thermal reaction (by approximately 40-60%), while the larger-sized nano-metal particles mainly protect more nano-metal particles from oxidation during preparation and transportation through an externally formed oxide film. There are no significant restrictions on the proportion of aluminum powder of different particle sizes.

[0051] At least two independent high-pressure pumping systems (such as skid-mounted plunger pumps) are required on the ground. One pump set is connected to one channel of a multi-channel column (such as the central tube) to pump the nano-metal dispersion, and the other pump set is connected to another channel (such as the annulus) to pump the phase change expansion liquid.

[0052] During the pumping process, the pumping volume and rate of the two liquids are strictly monitored and controlled using high-precision flow meters and pressure sensors. The two liquids travel thousands of meters from the ground within their respective pipelines, ultimately being injected into the enclosed working space from different outlets on the multi-channel coiled tubing unit 10. Throughout the entire transport process, they remain physically isolated and do not come into contact with each other.

[0053] In step S6, the nano-metal dispersion and the phase change expansion liquid are mixed within the target working space to form a high-energy reaction mixture. This typically employs a high-pressure jet impingement mixing process. The multi-channel coiled tubing unit 10 has a precisely designed flow channel. When the two liquids are pumped in, they are ejected at high speed through specially designed nozzles. The nozzles are precisely designed to either collide with each other or intersect at a specific angle. The two liquids form two or more powerful jets at extremely high speeds (determined by the ground pump pressure). When these high-speed jets violently collide within a pre-set formation fracture, the enormous kinetic energy is instantly converted into intense turbulence and shear force. Under this chaotic turbulent action, the two liquids are torn apart and dispersed at both macroscopic and microscopic levels, and forced to form a homogeneous mixture within milliseconds.

[0054] In step S7, the electric detonation device is controlled to generate an electric detonation in the high-energy reaction mixture, causing a cascade reaction in the high-energy reaction mixture. After the control console sends an electric detonation command to the electric detonation device, a high-voltage electric pulse reaches the electric detonation device downhole within microseconds via a cable. The electric detonation device is activated, releasing initial energy (high temperature, high pressure) sufficient to trigger the main reaction. The nano-metal particles undergo a violent, near-explosive thermochemical reaction with water. The core chemical reaction principle is (taking nano-aluminum metal particles as an example): 2Al (solid) + 3H2O (liquid / gas) = ​​Al2O3 (solid) + 3H2 (gas) + Q (16kJ / g).

[0055] This thermochemical reaction releases enormous chemical energy in a very short time, manifesting as temperatures of thousands of degrees Celsius and the presence of primary reaction gases. The immense heat generated by the thermochemical reaction is instantly transferred to the homogeneously mixed phase-change expanding liquid. Under high temperature and pressure, the phase-change expanding liquid absorbs energy far exceeding its boiling point, undergoing flash evaporation and instantly transforming from a liquid state into superheated steam under ultra-high pressure and ultra-high temperature. This physical phase change process efficiently converts the heat energy released by the chemical reaction into enormous volume expansion energy. The dramatic expansion of the phase-change expanding liquid, combined with the gases produced by the thermochemical reaction itself, causes the pressure within the target working space to surge dramatically to thousands or even tens of thousands of atmospheres (tens to hundreds of megapascals).

[0056] This high-temperature, high-pressure, high-energy gas, composed of chemically reacted gases and vaporized phase-change expanding liquids, becomes the direct working medium for fracturing. Because the rate of pressure increase far exceeds the rate of gas loss through permeation into the formation, the high-energy gas acts like a powerful, all-pervasive wedge. It first penetrates the initial fracture network, as this is the path of least resistance for pressure release. Driven by the immense pressure, stress concentrates at the tip of the initial fracture, causing it to rapidly expand, extend, and potentially connect with naturally occurring micro-fractures in the formation, ultimately forming an interconnected, three-dimensional, and complex fracturing network.

[0057] Taking nano-aluminum metal particles as an example, the final core reaction product is aluminum oxide (Al2O3). Crystalline aluminum oxide can act as a proppant in the cracks. Although the overall amount of aluminum oxide is relatively small, it is evenly distributed throughout the crack network, thus providing a flow-guiding and support effect.

[0058] In step S8, steps S5-S7 are executed cyclically. The first pulse not only creates a crack, but more importantly, it temporarily alters the stress state of the rock mass surrounding the crack. The second pressure pulse acts within a modified, dynamic stress field. This readily induces the main crack to bifurcate, deflect, and generate secondary microcracks.

[0059] The total amount of injected nano-metal dispersion and phase change expansion liquid, as well as the number of injection fracturing operations, can be adjusted according to the fracturing energy requirements of different target layers and fracture monitoring results. The total amount of nano-metal dispersion and phase change expansion liquid injected initially is controlled at 100m³. 3 Within this range. For target layers with low ground stress and well-developed original cracks, a construction method that reduces the number of passes and increases the amount of each pass is adopted; for target layers with high ground stress and no well-developed original cracks, a construction method that increases the number of passes is adopted.

[0060] In step S9, the setting packer on the multi-channel coiled tubing assembly 10 is released, and the multi-channel coiled tubing assembly 10 is lifted. For mechanical packers, specific operations on the entire tubing string are typically required from ground equipment, such as lifting the tubing string. This action triggers the contraction of the mechanical slips and rubber sleeves inside the packer, causing it to disengage from the casing wall. For hydraulic packers, release is achieved by changing the fluid pressure in a control line or main pipeline. After the packer release is confirmed, the coiled tubing assembly begins to lift the multi-channel coiled tubing assembly 10.

[0061] The implementation principle of a high-energy gas fracturing method according to an embodiment of this application is as follows: A high-frequency shock wave is generated through an initial electric detonation, creating micro-fractures in the wellbore and near-wellbore zone, reducing formation fracturing pressure. Then, the shock wave and thermal energy generated by the electric detonation device trigger a thermochemical reaction between the nano-metal particles and water. The thermochemical reaction generates high heat, causing the phase-change expansion liquid to instantly vaporize and expand, generating a huge pressure pulse and significantly increasing the fracture volume. The nano-metal dispersion and the phase-change expansion liquid are mixed only after injection into the target space and fractures, avoiding the high-pressure transport risks that may arise from surface mixing. Multiple thermochemical reactions and the vaporization of the phase-change expansion liquid achieve pulsed loading of the formation. This repeated impact load can induce fatigue failure in the rock, forming a more complex fracture network structure than a single fracturing operation.

[0062] This application also discloses a high-energy gas fracturing system.

[0063] Figure 2 This is a schematic diagram of a high-energy gas fracturing system according to an embodiment of this application. (Refer to...) Figure 2 The high-energy gas fracturing system includes a multi-channel coiled tubing unit 10, a packer setting pumping unit 20, a monitoring unit 30, an electric detonation surface unit 40, a phase change expansion liquid pumping unit 50, a nano-metal dispersion pumping unit 60, and a circulation tank 70. The packer setting pumping unit 20, the monitoring unit 30, the electric detonation surface unit 40, the phase change expansion liquid pumping unit 50, and the nano-metal dispersion pumping unit 60 are all connected to the multi-channel coiled tubing unit 10. The multi-channel coiled tubing unit 10 is used to extend into the wellbore.

[0064] The multi-channel coiled tubing equipment 10 is equipped with an electric detonation device. The electric detonation ground equipment 40 is connected to the electric detonation device and is used to control the electric detonation device to generate an electric detonation in the target work space.

[0065] The phase change expansion liquid pumping device 50 is connected to the multi-channel continuous tubing device 10, and the phase change expansion liquid pumping device 50 is used to pump the phase change expansion liquid into the multi-channel continuous tubing device 10. The nano-metal dispersion pumping device 60 is connected to the multi-channel continuous tubing device 10, and the nano-metal dispersion pumping device 60 is used to pump nano-metal dispersion into the multi-channel continuous tubing device 10.

[0066] The multi-channel coiled tubing equipment is equipped with a setting packer, and the setting packer pumping device 20 is connected to the setting packer. If all fracturing points in the entire well section are perforated in advance, a cross-packer packer should be selected; if a hydraulic jet perforation tool is used, a bottom packer can be selected.

[0067] The multi-channel coiled tubing unit 10 is equipped with multiple sensors, and the monitoring device 30 is connected to the sensors. The sensors are used to monitor parameters such as pressure and temperature during the fracturing process. The circulation tank 70 is connected to the wellbore via pipeline, and the circulation tank 70 is used to contain wastewater from the wellbore.

[0068] Figure 3 This is a cross-sectional view of a multi-channel coiled tubing device in a high-energy gas fracturing system according to an embodiment of this application. (Refer to...) Figure 3 The multi-channel coiled tubing device 10 is provided with multiple coiled tubing channels 11 and prefabricated cables 12. The multiple coiled tubing channels 11 and the prefabricated cables 12 are connected by rubber 13 covering the multi-channel coiled tubing. The prefabricated cables 12 are used to connect the electric detonation ground equipment 40 and the electric detonation device. The prefabricated cables 12 are also used to connect the monitoring equipment 30 and multiple sensors on the multi-channel coiled tubing device 10.

[0069] In this embodiment, the multi-channel coiled tubing device 10 has three coiled tubing channels 11. The first coiled tubing channel 11 is used to inject the nano-metal dispersion liquid, the second coiled tubing channel 11 is used to inject the phase change expansion liquid, and the third coiled tubing channel 11 is used to provide pressure to ensure the setting of the setting packer when the setting packer is required under certain completion conditions.

[0070] The multi-channel coiled tubing device 10 has a rectangular cross-section; therefore, the injection head of the multi-channel coiled tubing device 10 is equipped with a rectangular clamping block and a blowout preventer of corresponding size. The size and shape of the coiled tubing, as well as the injection head accessories, can be optimized subsequently based on the actual wellbore size and channel requirements.

[0071] The multi-channel coiled tubing equipment 10 is also equipped with a coupling positioning tool. The coupling positioning tool can be a mechanical positioning tool or a magnetic positioning tool. The mechanical positioning tool relies on the change of ground weight for positioning, while the magnetic positioning tool needs to be connected to a cable to use electromagnetic induction for positioning.

[0072] The multi-channel coiled tubing equipment 10 is also equipped with a check valve. The check valve forms a barrier between the nano-metal dispersion injection channel inside the multi-channel coiled tubing equipment 10 and the electric detonation device. The check valve can also serve as a barrier between the bottom hole cascade reaction and the inside of the tubing.

[0073] The implementation principle of a high-energy gas fracturing system according to an embodiment of this application is as follows: both the phase change expansion liquid and the nano-metal dispersion have independent pumping equipment, which allows the injection rate and ratio of the phase change expansion liquid and the nano-metal dispersion to be adjusted according to the formation conditions, thereby achieving precise control of the fracturing process.

[0074] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A high-energy gas fracturing method, characterized in that, include: S2. The multi-channel coiled tubing equipment (10) is lowered into the wellbore, and the electric detonation device at the end of the multi-channel coiled tubing equipment (10) is brought into the target working space. S3. Operate the packer on the multi-channel coiled tubing equipment (10) to separate the target working space from the upper and lower wellbore. S4. Control the electric detonation device to generate an electric detonation in the target work space; S5. Inject nano-metal dispersion and phase change expansion liquid into the target working space through the multi-channel continuous tubing equipment (10); S6. Control the mixing of the nano-metal dispersion and the phase change expansion liquid in the target working space to form a high-energy reaction mixture; S7. Control the electric detonation device to generate an electric detonation in the high-energy reaction mixture, so that the high-energy reaction mixture undergoes a cascade reaction. S8. Repeat steps S5-S7; wherein the cascade reaction is as follows: the electric detonation generates shock waves and thermal energy in the high-energy reaction mixture; the shock waves and thermal energy generated by the electric detonation cause the nano-metal dispersion to undergo a thermochemical reaction; the heat generated by the thermochemical reaction of the nano-metal dispersion causes the phase change expansion liquid to vaporize.

2. The high-energy gas fracturing method according to claim 1, characterized in that, In step S5, the nano-metal dispersion includes nano-metal particles, thickener, water, and activator.

3. The high-energy gas fracturing method according to claim 2, characterized in that, In step S5, an oxide film is formed on the surface of the nano-metal particles.

4. The high-energy gas fracturing method according to claim 2, characterized in that, In step S5, the nano-metal dispersion comprises 0.4-0.5% of the nano-metal particles by mass, 0.15-0.25% of the thickener by mass, 5-8% of the activator by mass, and water.

5. The high-energy gas fracturing method according to claim 2, characterized in that, In step S5, the volume ratio of the nano-metal dispersion to the phase change expansion liquid is 1:5-1:

4.

6. The high-energy gas fracturing method according to claim 1, characterized in that, In step S4, the target work space contains water for electric shock blasting.

7. The high-energy gas fracturing method according to claim 1, characterized in that, The steps preceding step S2 also include: S1. Perforate all predetermined target working spaces to establish connection channels between the wellbore and each formation.

8. The high-energy gas fracturing method according to claim 1, characterized in that, The process after step S8 also includes: S9. Release the setting packer on the multi-channel coiled tubing equipment (10) and lift the multi-channel coiled tubing equipment (10).

9. A high-energy gas fracturing system, characterized in that, include: A multi-channel coiled tubing unit (10) is installed in the wellbore, and the multi-channel coiled tubing unit (10) is equipped with an electric detonation device; An electric detonation ground device (40) is connected to the electric detonation device, and the electric detonation ground device (40) is used to control the electric detonation device to generate an electric detonation in the target work space; A phase change expansion liquid pumping device (50) is connected to the multi-channel coiled tubing device (10), and the phase change expansion liquid pumping device (50) is used to pump phase change expansion liquid into the multi-channel coiled tubing device (10); A nano-metal dispersion pumping device (60) is connected to the multi-channel continuous tubing device (10), and the nano-metal dispersion pumping device (60) is used to pump nano-metal dispersion into the multi-channel continuous tubing device (10).

10. The high-energy gas fracturing system according to claim 9, characterized in that, It also includes a packer pumping device (20), a monitoring device (30), and a circulation tank (70). The multi-channel coiled tubing equipment (10) is equipped with a packer, and the packer pumping device (20) is connected to the packer. The multi-channel coiled tubing equipment (10) is equipped with multiple sensors, and the monitoring device (30) is connected to the sensors. The circulation tank (70) is connected to the wellbore through a pipeline and is used to contain wastewater in the wellbore.

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