Micro-difference high-intensity electric explosion fracturing and permeability enhancement system and method for gas-bearing reservoirs and geothermal reservoirs

Abstract

The present invention proposes a micro-difference high-intensity electric explosion fracturing and permeability enhancement system and method for gas-bearing reservoirs and geothermal reservoirs. The permeability enhancement system includes N discharge electrodes, an electrode installation device, a plurality of high-voltage electric energy storage containers, a plurality of control switches, and N intelligent millisecond delay switches for respectively controlling the on and off of the N discharge electrodes; the electrode installation device includes N+1 installation disks arranged at intervals along the height direction, and a support blocking part and a discharge electrode are arranged between two adjacent installation disks; the support blocking part can block the shock wave emitted by the discharge electrode, and the circumferential angle of the support blocking part is adjustable. The present invention uses the support blocking part to form a blind area to block the shock wave, form a protection area, and realize directional regional fracturing; according to the actual situation of the reservoir, shock waves in different directions are released, and the intelligent delay switch is used to control the simultaneous / delayed release of the energy of the N discharge electrodes, and the superposition obtains stronger energy to improve the reservoir fracturing and permeability enhancement effect.

Description

Technical Field

[0001] The invention belongs to the technical field of coal seam fracturing and permeability enhancement, and specifically relates to a micro-difference high-intensity electric explosion fracturing and permeability enhancement system and a heat and energy extraction method for gas-bearing reservoirs and geothermal reservoirs. Background Art

[0002] Shale gas, coalbed methane, shallow biogas and tight sandstone gas are important components of unconventional natural gas. The development of unconventional natural gas in China is limited by the particularity of reservoir geology, resulting in low permeability, low reservoir pressure, and high horizontal ground stress. As a result, the exploitation and utilization of unconventional oil and gas has always been at a low level.

[0003] The shock wave generated by high-intensity electric detonation technology is conducive to the formation of a complex fracture network in the gas-bearing reservoir. When the shock wave acts on the reservoir, the stress value carried by the shock wave is greater than the compressive or tensile strength of the reservoir, and the reservoir ruptures to produce cracks. The stress shock wave penetrates the cracks and continues to propagate. As the transmission distance increases, the energy carried by the shock wave dissipates, and the stress value decreases, causing it to decay into a seismic stress wave. The seismic wave generates shear waves at the interface between different media, stripping off the adhesive on the surface of the seepage channel and unblocking the gas migration channel in the reservoir. The vibration of the seismic wave on the reservoir can also increase the micro-cracks in the reservoir and reduce the surface tension, which is beneficial to the desorption and diffusion of natural gas molecules inside the reservoir, and strengthening the extraction of unconventional natural gas such as shale gas, shallow biogas and tight sandstone gas, which is conducive to filling the gap between natural gas supply and demand and realizing the safe and efficient development and utilization of clean energy.

[0004] For example, the multi-channel segmented micro-difference rock breaking system and method based on high-intensity electric blasting technology disclosed in CN 202410139862.6 utilizes the millisecond delay characteristics of multiple high-voltage electric energy storage containers and intelligent millisecond delay switches to achieve controllable explosion energy and ensure high accuracy of energy output. It also utilizes the characteristics of segmented arrangement of discharge electrodes in the blast hole to achieve multi-layer rock mass with different micro-difference fracturing strengths in different energy segments. However, the circumferential angle of the shock wave released by the discharge electrode of this technology cannot be adjusted, and shock waves in different directions cannot be released according to the actual conditions of different layers of rock mass.

[0005] In addition, geothermal energy, as an important clean and renewable energy, has the characteristics of low carbon, environmental protection, stability and high efficiency. Compared with wind energy, solar energy and other energy sources, it is not affected by external factors such as seasons, climate, day and night, and the power generation efficiency is 73%, which is about 5.2 times that of solar energy and 3.5 times that of wind energy. It is a realistic and competitive new energy. The efficient development and utilization of renewable heat energy inside the earth is conducive to alleviating the problem of national energy shortage. Geothermal development and utilization mostly adopts the creation of micro-crack networks inside geothermal reservoirs to increase fluid seepage and increase heat exchange area. The existing technology is to introduce fracturing fluid into geothermal holes to fractur the reservoir to create cracks, but due to the pump pressure limit of the fracturing fluid, the fracturing range of geothermal reservoirs is limited, and the permeability effect is poor. Summary of the invention

[0006] The present invention aims to solve the technical problems existing in the prior art. The first purpose of the present invention is to provide a micro-difference high-intensity electric detonation fracturing permeability enhancement system for gas-containing reservoirs and geothermal reservoirs. The second purpose of the present invention is to provide a method for extracting heat and energy using the aforementioned permeability enhancement system.

[0007] To achieve the above-mentioned first purpose, the present invention adopts the following technical scheme: a micro-difference high-intensity electric explosion fracturing and permeability enhancement system for gas-bearing reservoirs and geothermal reservoirs, comprising N discharge electrodes capable of releasing the same or different energies located in a reservoir shaft, an electrode installation device for installing the N discharge electrodes, a plurality of high-voltage electric energy storage containers with adjustable energy storage connected to the discharge electrodes by cables, a power supply for providing electric energy, a plurality of control switches for respectively controlling the on and off of the plurality of high-voltage electric energy storage containers, and N intelligent millisecond delay switches for respectively controlling the on and off of the N discharge electrodes, wherein N is an integer greater than or equal to 2; the electrode installation device comprises N+1 installation disks spaced apart in a height direction, a support blocking portion and a discharge electrode are arranged between two adjacent installation disks, and a cable laying channel for laying cables for the discharge electrodes is provided in the installation disk and the support blocking portion; the support blocking portion can block the shock wave emitted by the discharge electrode, the support blocking portion is circumferentially distributed outside the discharge electrode corresponding thereto, and the circumferential angle of the support blocking portion is adjustable.

[0008] The above technical scheme utilizes the support and blocking part to form a blind zone to block the shock wave. The reservoir in the blind zone ray area is no longer fractured, and a protection area can be formed to achieve directional regional fracture. The circumferential angle of the support and blocking part is adjustable, and shock waves in different directions can be released according to the actual situation of the reservoir. The intelligent delay switch is used to control the simultaneous / delayed release of the energy of N discharge electrodes, which can be superimposed to obtain stronger energy and improve the reservoir fracturing and permeability enhancement effect. Moreover, different output energies and delay times are set to cyclically layer and stagger the fracture of reservoirs at different positions at different angles, which can ultimately achieve high-energy, large-scale fracturing and permeability enhancement of reservoirs and efficiently develop and utilize clean energy.

[0009] In a preferred embodiment of the present invention, the support blocking portion includes a support bar located outside the discharge electrode, or a plurality of support sub-bars circumferentially distributed outside the discharge electrode, and the support bar / support sub-bars are detachably connected to the mounting plate.

[0010] The above technical solution can replace support strips of different circumferential lengths according to actual conditions to increase / decrease the range of the blind area, and can also adjust the position and range of the blind area by setting support sub-strips of different numbers / circumferential positions to further achieve directional treatment of cracks.

[0011] In a preferred embodiment of the present invention, a mounting plate connected to a supporting and blocking portion with adjustable circumferential angle is provided with a plurality of adjustment holes spaced apart circumferentially, and the supporting and blocking portion is detachably fixedly connected to some of the adjustment holes on the mounting plate by bolts.

[0012] The above technical solution utilizes bolts and a plurality of adjustment holes to adjust the circumferential spacing angle of the support blocking portion, and the connection is reliable.

[0013] In a preferred embodiment of the present invention, the discharge electrode is fixedly connected to the mounting plate above and / or below it; or the discharge electrode is suspended below the mounting plate above it through its cable.

[0014] In a preferred embodiment of the present invention, the delay time of N intelligent millisecond delay switches can be set, the delay time set for the N discharge electrodes is the same or different; and / or the energy output by the N discharge electrodes is the same or different.

[0015] In another preferred embodiment of the present invention, the penetration enhancement system also includes a wireless controller, the energy control end of the wireless controller is respectively connected to the enable ends of multiple high-voltage energy storage containers, and the discharge delay control end of the wireless controller is respectively connected to the enable ends of N intelligent millisecond delay switches.

[0016] The above technical solution charges and sets the voltage of the high-voltage energy storage container through a wireless controller, and sets the millisecond delay time of the intelligent millisecond delay switch through the wireless controller, which is more convenient to operate.

[0017] To achieve the above-mentioned second purpose, the present invention adopts the following technical scheme: a heat extraction and energy extraction method using a micro-difference high-intensity electric detonation fracturing and permeability enhancement system for gas-bearing reservoirs and geothermal reservoirs, comprising the following steps: constructing a micro-difference high-intensity electric detonation fracturing and permeability enhancement system; constructing an injection well and a production well extending into or penetrating the geothermal reservoir from the ground, injecting a heat exchange fluid into the injection well, and the production well is filled with a heat exchange fluid, and the heat exchange fluid is a discharge medium; installing an electrode installation device and N discharge electrodes in the production well and immersing them in the heat exchange fluid, so that the support and blocking parts at different heights correspond to the protection area of ​​the reservoir and the circumferential angles are equal, and the coverage area of ​​the shock wave emitted by the discharge electrode corresponds to the fracturing area and the circumferential angles are equal; setting the output energy of the N discharge electrodes and the delay time of the N intelligent millisecond delay switches, and implementing geothermal reservoir fracturing and permeability enhancement in the area where the injection well and the production well are located; installing a geothermal reservoir heat extraction and energy extraction device to extract heat and energy from the production well.

[0018] In the above technical scheme, the fracturing and permeability enhancement system is provided with an electrode installation device and N discharge electrodes, which can complete the release of shock waves in different directions by micro-difference high-intensity electric explosion. After the shock wave decays into a stress wave through the wall of the production well, it can be superimposed to fracture the geothermal reservoir under the action of the millisecond delay time. Different output energies and delay times are set to cyclically layer and stagger the fracturing of geothermal reservoirs at different positions by angles, and fracture and permeability enhancement of the geothermal reservoirs in the area where the injection well and the production well are located is implemented to generate cracks. The heat exchange fluid in the injection well enters the cracks to absorb the geothermal energy of the lower geothermal reservoir and then enters the production well, which is conducive to the efficient development of geothermal resources.

[0019] In another preferred embodiment of the present invention, when the electrode installation device and N discharge electrodes are installed in a production well, the following steps are also included: obtaining the rock powder distribution area of ​​the cross-sections at different heights of the production well; determining the angles of the protection areas and the angles of the fracturing areas at different heights according to the rock powder distribution area, so that the supporting and blocking parts at different heights correspond to the protection areas and the angles are equal, and the coverage area of ​​the shock wave emitted by the discharge electrode corresponds to the fracturing area and the angles are equal.

[0020] The above technical solution determines the angles of protection areas and fracturing areas at different heights according to the rock powder distribution areas in cross sections at different heights of the production well, making it easier to adjust the circumferential angle of the support and blocking part outside the production well in advance, which is more convenient than adjusting it in the production well.

[0021] In another preferred embodiment of the present invention, the specific method for setting the output energy of N discharge electrodes is:

[0022]

[0023] Among them, E iis the actual output energy of the i-th discharge electrode; K is the correction coefficient; ε is the energy loss coefficient; E0 is the standard output energy of the discharge electrode; h i is the thickness of the rock formation at the i-th discharge electrode; δ i The compressive strength of the rock formation at the i-th discharge electrode; σ i The tensile strength of the rock formation at the i-th discharge electrode; l i is the length of the structural surface at the i-th discharge electrode; R is the fracture radius formed by the shock wave generated by a single discharge electrode to destroy the rock mass; α is the energy superposition coefficient related to the delay time.

[0024] The above technical scheme comprehensively determines the actual output energy of the discharge electrode based on multiple factors such as the standard output energy of the discharge electrode, the thickness of the rock formation at the discharge electrode, the compressive strength and tensile strength of the rock formation at the discharge electrode, the length of the structural surface at the discharge electrode, and the fracture radius formed by the shock wave generated by a single discharge electrode to destroy the rock mass, and takes into account the energy loss coefficient to achieve the purpose of precise control.

[0025] In another preferred embodiment of the present invention, the specific method for setting the delay time of N intelligent millisecond delay switches is:

[0026]

[0027] Where ΔT is the delay time, s; K′ is the site coefficient related to rock properties and discharge parameters; The actual output energy of the first discharge electrode, J; The actual output energy of the second discharge electrode, J; c S is the propagation speed of the shock wave generated by the permeability enhancement system of the present invention, m / s; R is the fracture radius formed by the shock wave generated by a single discharge electrode to destroy the rock mass, m; α is the energy superposition coefficient related to the delay time; β is the delay time jump index.

[0028] The above technical scheme comprehensively determines the delay time of N intelligent millisecond delay switches based on multiple factors such as the ratio of the actual output energy of the first and second discharge electrodes, the propagation speed of the shock wave, and the fracture radius formed by the shock wave generated by a single discharge electrode to destroy the rock mass, so as to achieve the purpose of precise control.

[0029] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0031] Figure 1 It is a schematic structural diagram of a micro-difference high-intensity electric explosion fracturing and permeability enhancement system for gas-bearing reservoirs and geothermal reservoirs according to an embodiment.

[0032] Figure 2 It is a partial cross-sectional schematic diagram of N discharge electrodes installed in an electrode mounting device.

[0033] Figure 3 It is a structural diagram of the support bar.

[0034] Figure 4 It is a structural schematic diagram of a support bar with a through hole.

[0035] Figure 5 It is a schematic diagram of using the micro-difference high-intensity electric explosion fracturing and permeability enhancement system for gas-bearing reservoirs and geothermal reservoirs to extract thermal energy from geothermal reservoirs.

[0036] The figure marks in the drawings of the specification include: power supply 1, system main switch 2, control switch 3, high-voltage energy storage container 4, intelligent millisecond delay switch 5, cable 6, electrode installation device 7, large cable conduction hole 8, small cable conduction hole 9, discharge electrode 10, discharge electrode positive pole 101, discharge electrode negative pole 102, installation plate 11, support blocking part 12, adjustment hole 13, through hole 14. DETAILED DESCRIPTION

[0037] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0038] In the description of the present invention, it is to be understood that the terms “longitudinal”, “lateral”, “vertical”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside” and “outside” etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0039] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0040] Embodiment 1

[0041] This embodiment provides a micro-difference high-intensity electric explosion fracturing and permeability enhancement system for gas-bearing reservoirs and geothermal reservoirs, such as Figure 1 As shown, in a preferred embodiment, the permeability enhancement system includes N discharge electrodes 10 capable of releasing the same or different energies and located in a vertical shaft of a reservoir (including a gas-bearing reservoir and a geothermal reservoir), an electrode installation device 7 for installing the N discharge electrodes 10, a plurality of high-voltage electric energy storage containers 4 with adjustable energy storage connected to the discharge electrodes 10 via cables 6, a power supply 1 for providing electric energy, a plurality of control switches 3 for respectively controlling the on and off of the plurality of high-voltage electric energy storage containers 4, and N intelligent millisecond delay switches 5 for respectively controlling the on and off of the N discharge electrodes 10, wherein N is an integer greater than or equal to 2.

[0042] like Figure 1 As shown, the electrode installation device 7 includes N+1 installation plates 11 spaced apart in the height direction, and a support and blocking portion 12 and a discharge electrode 10 are arranged between two adjacent installation plates 11. Specifically, the discharge electrode 10 can be fixed to the installation plate 11 above and / or below it, or the discharge electrode 10 can be suspended below the installation plate 11 above it through its cable 6. The installation plate 11 and the support and blocking portion 12 are both provided with a laying channel for laying the cable 6 of the discharge electrode 10, so as to facilitate the laying of the cable 6. Figure 1 and Figure 3 As shown, the wiring channel of the mounting plate 11 is a hollow interior thereof, and a large cable conducting hole 8 communicating with the wiring channel is provided in the middle of the top mounting plate 11, and the cables 6 of the N discharge electrodes 10 are inserted through the large cable conducting hole 8, and the wiring channel of the supporting blocking portion 12 is a small cable conducting hole 9 penetrating vertically.

[0043] The support and blocking part 12 can block the shock wave emitted by the discharge electrode 10. The support and blocking part 12 is circumferentially distributed outside the corresponding discharge electrode 10, and the circumferential angle of the support and blocking part 12 is adjustable. The discharge electrode 10, the cable 6 and the electrode mounting device 7 all have the characteristics of high and low temperature resistance, high compressive strength, and high mechanical strength. In particular, the cable 6 must be reliably sealed and can prevent liquid (such as water) from immersion.

[0044] Among them, the power supply 1 provides the electric energy required by the equipment of the entire infiltration system. The power supply 1 is externally connected to the system main switch 2, which can control the power on of the entire infiltration system. A plurality of control switches 3 are connected on the line after the system main switch 2, and the plurality of control switches 3 are respectively connected to a plurality of high-voltage electric energy storage containers 4. N intelligent millisecond delay switches 5 are connected on the line after the high-voltage electric energy storage container 4, and the N intelligent millisecond delay switches 5 are respectively connected to the N discharge electrodes 10 through N cables 6. The cable 6 is a high-voltage cable. The electric energy of the high-voltage electric energy storage container 4 is transmitted to the corresponding discharge electrode 10 through the cable 6, forming a shock wave-induced fracturing and infiltration reservoir. Preferably, the number of high-voltage electric energy storage containers 4 is adapted to the number of layers of the reservoir in which the shaft is located. For example, three high-voltage electric energy storage containers 4 are provided, and correspondingly, there are also three control switches 3. At least one discharge electrode 10 is arranged corresponding to each reservoir layer in a shaft, that is, at least one discharge electrode 10 is provided corresponding to one high-voltage electric energy storage container 4. This embodiment is described by taking one discharge electrode 10 as an example, and then the three high-voltage electric energy storage containers 4 are respectively connected to three discharge electrodes 10.

[0045] The electric energy of the high-voltage electric energy storage container 4 of the present invention is released through the corresponding discharge electrode 10 to form a shock wave. By setting an intelligent millisecond delay switch 5 to control the circuit on and off of the discharge electrode 10 during the millisecond delay time, and utilizing the characteristics of the layered arrangement of the discharge electrode 10 in the shaft, segmented micro-difference fracturing of multiple layers of reservoirs is achieved. In addition, by adjusting the circumferential angle of the support and blocking portion 12 in advance, the support and blocking portions 12 outside the three discharge electrodes 10 are circumferentially layered and staggered in angle, and the support and blocking portions 12 are used to form a blind area to block the shock wave. The reservoir in the blind area ray area is no longer fractured, and a protection area can be formed to achieve directional regional fracturing. The supporting and blocking parts 12 are circumferentially layered and staggered in angles. The three discharge electrodes 10 can complete the release of shock waves in different directions by micro-difference high-intensity electric explosion. After the shock wave decays into a stress wave through the shaft wall, it can be superimposed to fracture the reservoir under the action of millisecond delay time. By setting different output energies and delay times of the discharge electrodes 10, the reservoirs at different positions are fractured in a cyclic layered and staggered manner at different angles, and ultimately high-energy, large-scale fracturing and permeability-enhancing reservoirs can be achieved, and clean energy can be efficiently developed and utilized.

[0046] One discharge electrode 10 of the present invention corresponds to two mounting plates 11 and one supporting and blocking portion 12, and is a three-section structure. When the circumferential angle of the supporting and blocking portion 12 is adjusted, the cable 6 remains in the supporting and blocking portion 12 and is not exposed.

[0047] Preferably, water is poured into the shaft, and the three discharge electrodes 10 are immersed in the water for operation. The water mainly provides the liquid-electric effect of the electric detonation fracturing and permeability enhancement system, thereby generating a shock wave. This operation mode is to break through the water medium to form a spherical shock wave (blocked by the discharge electrode positive electrode 101 and the discharge electrode negative electrode 102 above and below), and the corresponding blind area is also blocked due to the support blocking part 12.

[0048] In the present invention, the delay time of the three intelligent millisecond delay switches 5 can be set, and the delay time can be set to 0-30ms (incremented by 1ms), and the delay time set for the three discharge electrodes 10 is the same or different. For example, the same delay time of 1ms-30ms can be set between the three discharge electrodes 10 to perform micro-difference high-intensity electric explosion fracturing and permeability reservoir enhancement, or the three discharge electrodes 10 can be set with a delay time of 0ms to perform fracturing and permeability reservoir enhancement at the same time. Among them, from the perspective of shock waves, when the delay time of the three discharge electrodes 10 is the same, the energy superposition of simultaneous operations is the largest; when the delay time of the three discharge electrodes 10 is different, there may be a situation where the peaks and troughs cancel each other during the delayed operation. By setting different delay times, while obtaining the same fracturing effect, it can be ensured that the protected buildings at a long distance are not harmed by vibration.

[0049] In the present invention, the energy output by the three discharge electrodes 10 is the same or different. The energy output calculation formula of a single discharge electrode 10 is E=CU2(1 / 2), and the energy output of a single discharge electrode 10 is 0-600 kJ. Different / same electric energy is stored in three high-voltage electric energy storage containers 4, so that different / same energy release of the three discharge electrodes 10 can be realized to fracture the reservoir.

[0050] In another preferred embodiment of the present invention, the penetration system also includes a wireless controller (not shown in the figure), and the energy control end of the wireless controller is respectively connected to the enable ends of the three high-voltage electric energy storage containers 4, so that the three groups of high-voltage electric energy storage containers 4 can be charged and the voltage can be set through the wireless controller; the discharge delay control end of the wireless controller is respectively connected to the enable ends of the three intelligent millisecond delay switches 5, so that the millisecond delay time of the intelligent millisecond delay switch 5 can be set through the wireless controller, and the electric energy stored in the high-voltage electric energy storage container 4 can be released.

[0051] like Figure 1 and Figure 2 As shown, in one embodiment of the present invention, the support blocking portion 12 is a support bar located outside the discharge electrode 10, the support bar is an arc-shaped block, and the support bar is detachably connected to the mounting plate 11. By adjusting the circumferential position of the support bar, the circumferential position of the blind area can be changed to change the circumferential orientation of the shock wave; by replacing support bars of different circumferential lengths, the range of the protection area and the range of the fracture-inducing area can be adjusted.

[0052] It should be noted that the support blocking portion 12 may also be composed of a plurality of support sub-strips circumferentially distributed outside the discharge electrode 10, one of the support sub-strips being provided with a wiring channel for passing the cable 6, and the support sub-strips being detachably connected to the mounting plate 11, thereby a suitable number of support sub-strips may be selected according to actual conditions to form a blind area.

[0053] like Figure 1 and Figure 2 As shown, in the present invention, a plurality of adjustment holes 13 are arranged at intervals in the circumferential direction on the mounting plate 11 connected to the support and blocking portion 12 whose circumferential angle is adjustable, and the support and blocking portion 12 is detachably fixedly connected to some of the adjustment holes 13 on the mounting plate 11 by bolts. This embodiment is described by taking the arrangement of three discharge electrodes 10 as an example, and accordingly, the number of the support and blocking portions 12 is three, and the number of the mounting plates 11 is four. The middle support and blocking portion 12 is fixedly connected to the mounting plates 11 on both sides thereof, and only the upper and lower support and blocking portions 12 are detachably fixedly connected to the adjustment holes 13 on the corresponding mounting plates 11 by bolts. At this time, the circumferential position of the middle support and blocking portion 12 can also be changed by rotating the electrode mounting device 7.

[0054] like Figure 1 and Figure 2 As shown, specifically, the adjustment holes 13 on the top and bottom mounting plates 11 are through holes, and the adjustment holes 13 on the two middle mounting plates 11 are blind holes. The upper bolts pass through the adjustment holes 13 of the top mounting plate 11 and the support blocking portion 12 from top to bottom in sequence and are threadedly connected to the adjustment holes 13 on the mounting plate 11 below it, and the lower bolts pass through the adjustment holes 13 of the bottom mounting plate 11 and the support blocking portion 12 from bottom to top in sequence and are threadedly connected to the adjustment holes 13 on the mounting plate 11 above it.

[0055] like Figure 1 and Figure 4 As shown, preferably, a plurality of adjustment holes 13 are evenly distributed on the mounting plate 11 in the circumferential direction, and the upper and lower support and blocking parts 12 have a plurality of through holes 14 evenly distributed in the circumferential direction corresponding to the positions of the adjustment holes 13, and the bolts can be simultaneously inserted into the adjustment holes 13 and the through holes 14. For example, if there are fifteen adjustment holes 13 (the number of adjustment holes 13 is equally divided according to the number of discharge electrodes 10), then the central angle between two adjustment holes 13 is 24°, and there are six through holes 14 on the upper and lower support and blocking parts 12, and the central angle of the support and blocking parts 12 is 120°, then it can be determined that the blind area of ​​a single discharge electrode 10 is 120°, and the operating area (fracture-causing area) of the shock wave of a single discharge electrode 10 is 240°, and correspondingly, when the blind area is increased, the operating area will be reduced.

[0056] Embodiment 2

[0057] The present invention provides a method for extracting heat and energy by using the micro-difference high-intensity electric explosion fracturing and permeability enhancement system of embodiment 1, such as Figure 1 and Figure 5 As shown, the following steps are included:

[0058] S1. Construct a micro-difference high-intensity electric explosion fracturing and permeation enhancement system, which consists of a power supply 1, a system main switch 2, a control switch 3, a high-voltage electric energy storage container 4 and an intelligent millisecond delay switch 5. Figure 5 The electrode installation device 7 can control the circumferential position of the shock wave generated by the three discharge electrodes 10. Looking down at the shaft, the circumferential spacing angle of the three support and blocking parts 12 is 120° (specifically, it can be adjusted by bolts and adjustment holes 13). Looking straight at the shaft, the spacing distance of the three discharge electrodes 10 is 0.5m.

[0059] S2. Injection wells and production wells are constructed from the ground that extend into or penetrate the geothermal reservoir. Perforating bullets are preferably used to perforate the wellbore of the injection well and production well near the geothermal reservoir, and cementing is performed to provide an operating basis for the discharge electrode 10 to fracture and increase the permeability of the reservoir. Heat exchange fluid is injected into the injection well, and the production well is filled with heat exchange fluid. The heat exchange fluid is a discharge medium, preferably water, or an aqueous solution of sodium chloride, which can conduct electricity and can be used as a heat storage medium.

[0060] S3. By lowering the cable 6, the electrode installation device 7 and N (N is three as an example) discharge electrodes 10 are installed in the production well and immersed in the heat exchange fluid, so that the support and blocking parts 12 at different heights correspond to the protection area of ​​the reservoir and have equal circumferential angles, and the coverage area of ​​the shock wave emitted by the discharge electrode 10 corresponds to the fracturing area and has equal circumferential angles. Among them, for shallower than 1000m, the wellhead preset fixed bracket combined with the electric winch can be used to lower the cable 6 to the fracturing target layer, and for deeper than 1000m, a well repair vehicle combined with an electric winch and a steel rod bundled with the cable 6 that can be connected in sections are used. It is preferred that the distance between the electrode installation device 7 and the end of the oil rod is 1-2m, and the cable 6 is slowly lowered by the well repair vehicle to allow the electrode installation device 7 and the discharge electrode 10 to reach the fracturing target layer.

[0061] S4, setting the output energy of the three discharge electrodes 10 and the delay time of the three intelligent millisecond delay switches 5 through the wireless controller, cyclically layering and staggering the fracturing and permeability enhancement of geothermal reservoirs at different positions from bottom to top, implementing the fracturing and permeability enhancement of geothermal reservoirs in the areas where the injection wells and production wells are located to generate fissures, so that the heat exchange fluid injected from the injection well enters the fissures to absorb geothermal energy and then enters the production well.

[0062] S5. Install geothermal reservoir heat and energy extraction equipment to extract heat and energy from production wells, and use the obtained heat energy to generate electricity through geothermal power stations.

[0063] Among them, before the electrode installation device 7 and the three discharge electrodes 10 are installed in the production well, the following steps are also performed: obtaining the rock powder distribution area of ​​the cross section at different heights of the production well; then determining the angles of the protection area and the angles of the fracturing area at different heights according to the rock powder distribution area, so that the support blocking parts 12 at different heights correspond to the protection area and the angles are equal, and the coverage area of ​​the shock wave emitted by the discharge electrode 10 corresponds to the fracturing area and the angles are equal.

[0064] The specific method for setting the output energy of the three discharge electrodes 10 is as follows:

[0065]

[0066] Among them, E i is the actual output energy of the i-th discharge electrode, J; K is the correction coefficient; ε is the energy loss coefficient; E0 is the standard output energy of the discharge electrode, J; h i is the thickness of the rock layer at the i-th discharge electrode, m; δ i The compressive strength of the rock formation at the i-th discharge electrode, Pa; σ i Tensile strength of the rock formation at the i-th discharge electrode, Pa; l i is the length of the structural surface at the i-th discharge electrode, m; R is the fracture radius formed by the shock wave generated by a single discharge electrode to destroy the rock mass, m; α is the energy superposition coefficient related to the delay time.

[0067] It should be noted that in the above formulas, all coefficients are constants obtained through experiments.

[0068] The specific method for setting the delay time of the three intelligent millisecond delay switches 5 is as follows:

[0069]

[0070] Where ΔT is the delay time, s; K′ is the site coefficient related to rock properties and discharge parameters; is the actual output energy of the first discharge electrode, J; is the actual output energy of the second discharge electrode, J; c S is the propagation speed of the shock wave generated by the permeability enhancement system, m / s; R is the fracture radius formed by the shock wave generated by a single discharge electrode to destroy the rock mass, m; α is the energy superposition coefficient related to the delay time; β is the delay time jump index.

[0071] It should be noted that in the above formula, all coefficients are constants obtained through experiments, and when α and β are not 1, c needs to be removed. S , the unit of R is only taken as the numerical value for calculation. After the calculation is completed and the result is obtained, ΔT is added with the unit s.

[0072] In this embodiment, the three supporting and blocking parts 12 corresponding to the three discharge electrodes 10 are staggered and distributed in circumferential layers through the electrode installation device 7, so that the micro-difference high-intensity electric detonation technology can release shock waves in different directions. After the shock waves are attenuated into stress waves through the wall of the production well, they can be superimposed to fracture the geothermal reservoir under the action of the millisecond delay time. Different output energies and delay times are set to cycle, layer, and stagger the fracture of geothermal reservoirs at different positions at different angles, and finally high-energy, large-scale fracture and permeability geothermal reservoirs can be achieved and geothermal resources can be efficiently developed and utilized. In the description of this specification, the description of the reference terms "preferred embodiment", "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. 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.

[0073] Although the 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 claims and their equivalents.

Claims

1. A micro-difference high-intensity electric explosion fracturing permeability enhancement system for gas-bearing reservoirs and geothermal reservoirs, the permeability enhancement system comprising N discharge electrodes capable of releasing the same or different energies located in a reservoir shaft, an electrode mounting device for mounting the N discharge electrodes, a plurality of high-voltage electric energy storage containers with adjustable energy storage connected to the discharge electrodes by cables, a power supply for providing electric energy, a plurality of control switches for respectively controlling the on and off of the plurality of high-voltage electric energy storage containers, and N intelligent millisecond delay switches for respectively controlling the on and off of the N discharge electrodes, wherein N is an integer greater than or equal to 2; characterized in that: The electrode installation device comprises N+1 installation plates arranged at intervals in the height direction, a support blocking portion and the discharge electrode are arranged between two adjacent installation plates, and a cable laying channel for laying cables of the discharge electrode is provided in the installation plate and the support blocking portion; The support and blocking parts can block the shock waves emitted by the discharge electrode. The support and blocking parts are circumferentially distributed outside the discharge electrode corresponding thereto, and the circumferential angle of the support and blocking parts is adjustable. A plurality of adjustment holes spaced apart in the circumferential direction are arranged on the mounting plate connected to the support and blocking part whose circumferential angle is adjustable. The support and blocking part is detachably fixedly connected to some of the adjustment holes on the mounting plate by bolts.

2. According to the micro-difference high-intensity electric detonation fracturing and permeability enhancement system for gas-bearing reservoirs and geothermal reservoirs in claim 1, the support and blocking part includes a support bar located outside the discharge electrode, or a plurality of support sub-bars distributed circumferentially outside the discharge electrode, and the support bar / support sub-bars are detachably connected to the mounting plate.

3. The micro-difference high-intensity electric detonation fracturing and permeability enhancement system for gas-bearing reservoirs and geothermal reservoirs according to claim 1 is characterized in that: The discharge electrode is fixedly connected to the mounting plate above and / or below the discharge electrode; Alternatively, the discharge electrode is suspended below the mounting plate above the discharge electrode through its cable.

4. The micro-difference high-intensity electric detonation fracturing and permeability enhancement system for gas-bearing reservoirs and geothermal reservoirs according to any one of claims 1 to 3, characterized in that: The delay time of the N intelligent millisecond delay switches can be set, and the delay time set for the N discharge electrodes is the same or different; And / or the energies output by the N discharge electrodes are the same or different.

5. The micro-difference high-intensity electric detonation fracturing and permeability enhancement system for gas-bearing reservoirs and geothermal reservoirs according to any one of claims 1-3, further comprising a wireless controller, wherein the energy control end of the wireless controller is respectively connected to the enable ends of the plurality of said high-voltage electric energy storage containers, and the discharge delay control end of the wireless controller is respectively connected to the enable ends of the N said intelligent millisecond delay switches.

6. A method for extracting heat and energy using the micro-difference high-intensity electric detonation fracturing permeability enhancement system for gas-bearing reservoirs and geothermal reservoirs according to any one of claims 1 to 5, characterized in that: The steps include: Constructing the micro-difference high-intensity electric explosion fracturing and permeability enhancement system; Constructing an injection well and a production well extending into or penetrating the geothermal reservoir from the ground, injecting a heat exchange fluid into the injection well, and filling the production well with a heat exchange fluid, wherein the heat exchange fluid is a discharge medium; An electrode installation device and N discharge electrodes are installed in a production well and immersed in a heat exchange fluid, so that the support and blocking parts at different heights correspond to the protection area of ​​the reservoir and have equal circumferential angles, and the coverage area of ​​the shock wave emitted by the discharge electrode corresponds to the fracturing area and has equal circumferential angles; Setting the output energy of N discharge electrodes and the delay time of N intelligent millisecond delay switches to implement fracturing and permeability enhancement of geothermal reservoirs in the areas where injection wells and production wells are located; Install geothermal reservoir heat and energy extraction equipment to extract heat and energy from production wells.

7. The heat and energy extraction method according to claim 6, characterized in that: Before installing the electrode installation device and N discharge electrodes in the production well, the following steps are also required: Obtain rock powder distribution areas at cross sections at different heights of the production well; The angles of the protection area and the fracturing area at different heights are determined according to the distribution area of ​​rock powder, so that the support and blocking parts at different heights correspond to the protection area and the angles are equal, and the coverage area of ​​the shock wave emitted by the discharge electrode corresponds to the fracturing area and the angles are equal.

8. The heat and energy extraction method according to claim 6, characterized in that: The specific method for setting the output energy of the N discharge electrodes is: Among them, E i is the actual output energy of the i-th discharge electrode; K is the correction coefficient; ε is the energy loss coefficient; E0 is the standard output energy of the discharge electrode; h i is the thickness of the rock formation at the i-th discharge electrode; δ i The compressive strength of the rock formation at the i-th discharge electrode; σ i The tensile strength of the rock formation at the i-th discharge electrode; l i is the length of the structural surface at the i-th discharge electrode; R is the fracture radius formed by the shock wave generated by a single discharge electrode to destroy the rock mass; α is the energy superposition coefficient related to the delay time.

9. The heat and energy extraction method according to claim 6, characterized in that: The specific method for setting the delay time of N intelligent millisecond delay switches is: Where ΔT is the delay time; K′ is the site coefficient related to rock properties and discharge parameters; E i 1 is the actual output energy of the first discharge electrode; E i 2 is the actual output energy of the second discharge electrode; c S is the propagation speed of the shock wave formed by the permeability enhancement system; R is the fracture radius formed by the shock wave generated by a single discharge electrode to destroy the rock mass; α is the energy superposition coefficient related to the delay time; β is the delay time jump index.

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