WO2023227051A1 - 矿井下压裂及注支撑剂一体化装置及施工方法 - Google Patents

矿井下压裂及注支撑剂一体化装置及施工方法 Download PDF

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Publication number
WO2023227051A1
WO2023227051A1 PCT/CN2023/096204 CN2023096204W WO2023227051A1 WO 2023227051 A1 WO2023227051 A1 WO 2023227051A1 CN 2023096204 W CN2023096204 W CN 2023096204W WO 2023227051 A1 WO2023227051 A1 WO 2023227051A1
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WIPO (PCT)
Prior art keywords
pressure
sand
valve
fracturing
proppant
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PCT/CN2023/096204
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English (en)
French (fr)
Inventor
黄炳香
李浩泽
赵兴龙
陈树亮
邵鲁英
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中国矿业大学
徐州佑学矿业科技有限公司
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Publication of WO2023227051A1 publication Critical patent/WO2023227051A1/zh

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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/006—Production of coal-bed methane
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/25—Methods for stimulating production
    • E21B43/26—Methods for stimulating production by forming crevices or fractures
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/25—Methods for stimulating production
    • E21B43/26—Methods for stimulating production by forming crevices or fractures
    • E21B43/267—Methods for stimulating production by forming crevices or fractures reinforcing fractures by propping
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/10—Geothermal energy

Definitions

  • the invention belongs to the technical field of mining engineering and relates to fracturing-proppant injection equipment, specifically an integrated device and construction method for underground fracturing and proppant injection.
  • the main component of coalbed methane is methane, which releases less CO2 per unit of combustion than coal and oil. It does not produce ash or release toxins, making it a relatively clean energy source.
  • mining of coal seam methane also reduces the methane content of coal seams and gas pressure within coal seams, greatly reduces the probability of coal and gas outbursts and gas explosion accidents, and effectively ensures safe and efficient production of coal mines.
  • coal seams in China are low-permeability coal seams, with permeability generally ranging from 0.052 to 1.120mD.
  • Coalbed methane extraction is relatively difficult. Hydraulic fracturing, CO 2 phase change fracturing, nitrogen fracturing, etc. are often used to transform coal seams. Activate the bedding and cleats on both sides of the main fracture to form a complex interpenetrating fracture network system, increase the internal porosity of the coal seam, and improve its permeability.
  • Fracturing also changes the stress distribution in the coal seam fracture area, breaks the adsorption analysis equilibrium state of coal bed methane, and turns the adsorbed gas into a free state, making it easier to extract coal bed methane.
  • the commonly used fracturing methods include conventional fracturing and pulse fracturing.
  • Conventional fracturing uses a high-pressure and large-flow pump to inject fracturing fluid into the reservoir. Main hydraulic fractures are easily formed in the reservoir, resulting in local stress concentration. , there are fewer branch cracks.
  • pulse fracturing uses pulse circulation pump injection. Under the action of high-frequency pulse water pressure, the coal body is fatigued and damaged, resulting in hydraulic fractures in multiple directions that are not controlled by ground stress. At the same time, high-frequency pulse When water pressure impacts the coal body, it is easy to activate the original cracks in the coal body, causing the hydraulic cracks to communicate with the natural cracks to form a complex crack network. Both fracturing methods can be used to increase reservoir permeability. Conventional fracturing produces long fractures, while pulse fracturing produces many fractures.
  • the proppant distribution in the fractures with continuous sand injection is relatively dense, and the fracture closure rate is low.
  • the conductivity is relatively low; the proppant distribution in the fractures with pulse sand injection is columnar. , the conductivity of fractures is high, but the closure rate of fractures in unsupported areas is high, and the proppant spacing needs to be reasonably controlled so that there are still fluid channels in the fractures between proppant columns under the action of closing stress; multiple particle sizes and types Sand injection can provide reasonable proppant particle sizes and types for different fracture areas.
  • small particle size and high strength proppant is required at the fracture tip, and larger particle size or mixed particle size proppant is needed in the middle section of the fracture area to improve
  • the pores in the proppant area, and large-size proppant should be injected at the entrance of the fracture to prevent small-size proppant from migrating from the fracture to the inside of the borehole during drainage.
  • the multi-size and multi-type sand injection process is complicated. Therefore, different fracturing methods and sand injection methods can be used in different reservoir geological conditions and working environments.
  • the device includes a fracturing system and a proppant injection system.
  • the fracturing system includes a high-pressure pump or pulse pump connected end-to-end by high-pressure hoses, a high-pressure seal installation rod joint, and a high-pressure seal. Installation rod, hole sealer, high-pressure thin hose and hand pump.
  • the high-pressure pump or pulse pump and the high-pressure seal installation rod joint are connected through a high-pressure hose through a high-pressure pump outlet valve or pulse pump outlet valve, and are connected sequentially through a tee Connected to the fracturing valve, high-pressure hose pressure relief valve, flow sensor, and pressure sensor;
  • the proppant injection system includes a pressure balance valve connected end to end by rigid high-pressure pipes, a high-pressure sand tank pressure relief valve, a low-pressure sand adding port, and a low-pressure sand adding port. valve, high-pressure sand tank, high-pressure sand adding valve and sand injection pump.
  • the sand injection pump is connected with a fluid mixing inlet valve and a mixed fluid outlet valve.
  • the pressure balance valve and fluid mixing inlet valve are connected to the fracturing system through a high-pressure hose, and the mixing
  • the fluid outlet valve is connected to the high-pressure hose pressure relief valve through a high-pressure hose;
  • the flow sensor, pressure sensor and high-pressure sand tank are connected to the measurement and control instrument through a flow measurement line, a pressure measurement line and a sand quantity measurement line respectively.
  • the proppant injection system is vertical or horizontal.
  • the vertical sand injection system includes a high-pressure end rotating mechanism and a screw propelling mechanism.
  • the high-pressure end rotating mechanism controls the rotation of the screw propelling mechanism through the magnetic coupling of the large magnetic rotating mechanism.
  • the motor can be used horizontally, and the screw propulsion mechanism can be used vertically.
  • the motor controls the rotation of the high-pressure end rotating mechanism through the steering mechanism (such as the steering gear).
  • the screw propulsion mechanism enters a certain height inside the high-pressure sand tank to prevent the proppant from being stored in the high-pressure sand tank. The bottom is clogged.
  • the high-pressure sand tank is equipped with a stirring device.
  • the sand injection pump includes a high-pressure end rotating mechanism and a screw propelling mechanism.
  • the high-pressure end rotating mechanism rotates through large magnetic force.
  • the magnetic coupling of the mechanism controls the rotation of the screw propelling mechanism.
  • the fracturing valve, high-pressure hose pressure relief valve, and high-pressure pump outlet valve are high-pressure and wear-resistant ball valves.
  • the high-pressure sealing installation rod and hole sealer are hollow high-pressure resistant rods.
  • the flow sensor and the pressure sensor are high pressure resistant sensors.
  • the construction method of the integrated device for underground fracturing and proppant injection in any of the above mentioned mines includes the following steps:
  • a crawler drill to drill holes in the coal seam to a depth greater than 20m to avoid penetration of fracturing cracks into the tunnel;
  • the pressure balance valve Connect the pressure balance valve to the low-pressure sand adding valve and the high-pressure sand tank through a rigid high-pressure pipe.
  • the low-pressure sand adding valve is connected to the low-pressure sand adding port through a rigid high-pressure pipe.
  • the high-pressure sand tank is connected to the high-pressure sand adding valve and connected through a rigid high-pressure pipe. to the sand injection pump;
  • the sand injection pump is connected between the fluid mixing inlet valve and the mixed fluid outlet valve;
  • fracturing For high-pressure fracturing, close the fluid mixing inlet valve, mixed fluid outlet valve, pressure balance valve, high-pressure sand tank pressure relief valve, pulse pump outlet valve, low-pressure sand adding valve, and high-pressure sand adding valve, and open the fracturing valve and high-pressure pump.
  • the outlet valve uses a hand pump to inject fluid into the hole sealer through a high-pressure thin hose, causing the hole sealer to expand and seal the hole, and then inject high-pressure water through a high-pressure pump.
  • the high-pressure water passes through the high-pressure hose, high-pressure pump outlet valve, and tee in turn.
  • fracturing valve, flow sensor, pressure sensor, high-pressure seal installation rod joint, high-pressure seal installation rod, and hole sealer reach the fracturing position, the high-pressure water interacts with the borehole wall and forms fracturing cracks on the borehole wall. With the high pressure With the continuous injection of water, the cracks expand and extend to form a hydraulic fracture network;
  • Pulse fracturing close the fluid mixing inlet valve, mixed fluid outlet valve, pressure balance valve, high-pressure sand tank pressure relief valve, high-pressure pump outlet valve, low-pressure sand adding valve, high-pressure sand adding valve, and open the fracturing valve and pulse pump
  • the outlet valve uses a hand pump to inject fluid into the hole sealer through a high-pressure thin hose, causing the hole sealer to expand and seal the hole. Then pulse water is injected through the pulse pump. The pulse water passes through the high-pressure hose, pulse pump outlet valve, and tee in turn.
  • fracturing valve, flow sensor, pressure sensor, high-pressure seal installation rod joint, high-pressure seal installation rod, and hole sealer reach the fracturing position, the pulse water interacts with the borehole wall and forms a damage crack zone on the borehole wall. With the pulse With the continuous injection of water, the damaged fracture zone expands and extends to form a pulse hydraulic fracture network. After fracturing, turn off the high-pressure pump or pulse pump, and relieve the pressure on the pipeline through the high-pressure hose pressure relief valve. When the pressure reaches 0.5 ⁇ 1.0MPa , stop pressure relief and fracturing ends;
  • the high-pressure water discharged by the high-pressure pump or the pulse water discharged by the pulse pump after passing through the fluid mixing inlet valve, enters the screw propulsion mechanism of the sand injection pump, and is mixed with the proppant carried by the screw propulsion mechanism to form water-proppant solid-liquid
  • the two-phase fluid enters the fracturing-sand injection point through the mixed fluid outlet valve, high-pressure hose, flow sensor, pressure sensor, high-pressure seal installation rod joint, high-pressure seal installation rod, and hole sealer, and then enters the fracturing-sand injection point.
  • the high-pressure water or pulse water will After the water is injected for a period of time, open the pressure balance valve and the high-pressure sand adding valve, inject a section of proppant into the crack, and then inject a section of high-pressure water or pulse water, and repeat until the sand in the high-pressure sand tank is completely injected into the crack. , complete the pulse sand injection process;
  • Multi-particle size and multi-type sand injection When the time for the water-proppant solid-liquid mixture to be injected into the fracture network exceeds twice the fracturing time or the proppant in the high-pressure sand tank is completely injected into the fractures, stop injecting water into the fractures.
  • - Proppant solid-liquid mixed fluid complete the injection of the first proppant into the fracture, turn off the high-pressure pump or pulse pump, turn off the sand injection pump, open the high-pressure hose pressure relief valve to relieve pressure on the fracturing-sand injection system, close the pressure balance valve, High-pressure sand adding valve, slowly open the high-pressure sand tank pressure relief valve to relieve pressure in the high-pressure sand tank area.
  • the pressure balance valve and the high-pressure sand adding valve should be closed at this time, and only high-pressure water or pulse water should be injected into the crack. The high-pressure water or pulse water will flush out the sand-blocked interval.
  • the measurement and control instrument monitors When the pressure is no longer abnormal, open the pressure balance valve and high-pressure sand adding valve for sand injection;
  • the method of the present invention includes high-pressure fracturing continuous sand injection, high-pressure fracturing pulse sand injection, high-pressure fracturing multi-grain size multi-type sand injection, pulse fracturing continuous sand injection, pulse fracturing pulse sand injection, pulse fracturing multi-grain sand injection
  • high-pressure fracturing continuous sand injection high-pressure fracturing pulse sand injection
  • pulse fracturing pulse sand injection high-pressure fracturing multi-grain size multi-type sand injection
  • pulse fracturing continuous sand injection pulse fracturing pulse sand injection
  • pulse fracturing multi-grain sand injection There are many types of sand injection and other fracturing-sand injection methods.
  • the continuous sand injection for high-pressure fracturing is a method of continuously injecting proppant into the fracturing network after fracturing by a high-pressure pump; the pulse sand injection for high-pressure fracturing is intermittently injecting proppant into the fracturing network after fracturing by a high-pressure pump.
  • the method of pulse injection of proppant; the multi-particle size and multi-type sand injection for high-pressure fracturing is to sequentially inject different particle size proppant or different types of proppant or multi-particle size and multi-type proppant into the fracturing network after fracturing with a high-pressure pump.
  • the sand injection pump separates the screw propelling shaft from the high-pressure end rotating mechanism.
  • the screw propelling shaft and the high-pressure end rotating mechanism are coupled through the magnetic coupling of the large magnetic rotating mechanism to achieve rotational propulsion and sand delivery, which effectively solves the problem of the connection between the screw propelling shaft and the high-pressure end rotating mechanism. Seal issues.
  • a pressure balance valve is installed at the top of the sand tank.
  • the proppant in the sand tank is carried into the screw propulsion mechanism of the sand injection pump.
  • the proppant is transported to the fluid mixing inlet of the screw propulsion mechanism through the screw propulsion mechanism, and merges with the liquid-solid phase during the liquid-phase merging process.
  • the liquid-phase fluid carries the Transport the proppant into the fracture.
  • the proppant in the high-pressure sand tank migrates to the inside of the screw propulsion device under the action of water pressure and self-weight.
  • the proppant may be in the high-pressure sand adding valve. The section near the high-pressure sand tank is blocked, resulting in a large pressure difference between the left and right ends of the screw rotation and propelling shaft of the sand injection pump, which increases the wear of the screw rotation and propelling shaft.
  • a high-pressure stirring device needs to be connected to the high-pressure sand tank to make the support in the high-pressure sand tank
  • the agent distribution is relatively even, while avoiding the formation of sand blockage in the high-pressure sand tank near the high-pressure sand adding valve.
  • the proppant capacity in the high-pressure sand tank is a key factor affecting the fracturing sand injection process.
  • the pressure in the fracturing-sand injection system needs to be adjusted to a smaller range. If the pressure in the fracturing-sand injection system is in a high-pressure state, misoperation will result in sandblasting at the low-pressure sand injection end. There is potential danger to surrounding equipment, etc. Therefore, it is necessary to stop the high-pressure/pulse pump, remove the high pressure in the fracturing-sand injection system through the high-pressure hose pressure relief valve, and then replenish the amount of sand at the low-pressure sand adding port.
  • the high-pressure sand tank After filling the sand tank, sand is injected again. If the volume of the high-pressure sand tank is too small, proppant will need to be replenished multiple times, which will lead to complex sand injection operations, cumbersome processes, and low efficiency. However, if the high-pressure sand tank is too large, it will occupy a large space, and the working space in the underground tunnel is limited, so the high-pressure sand tank should not be too large. In order for the high-pressure sand tank to meet the tunnel space requirements and reduce the number of sand injections, the capacity of the high-pressure sand tank needs to be reasonably designed.
  • the proppant capacity in the high-pressure sand tank should be higher than half of the amount of sand added in a single time, so that the sand injection of a fracturing point can be completed at most twice;
  • the proppant capacity in the high-pressure sand tank should be greater than the amount of sand added in a single time, so that one sand addition can complete sand injection at a fracturing point;
  • the high-pressure sand tank should The proppant capacity within should ensure that each single particle size, single type or mixed particle size at each fracturing point can be injected in a single time; 4 Since the high-pressure sand tank is connected to the sand injection pump through a rigid pipe, the high-pressure sand tank is filled with The weight after being filled with proppant should ensure that it has little impact
  • the high pressure in the pipeline causes the pressure balance valve, fluid mixing inlet valve, high-pressure sand adding valve, mixed fluid outlet valve, fracturing valve and other valves to It is difficult to open, so preliminary pressure relief in the pipeline is required. If all the water in the pipeline is drained, not only will the drainage time be longer, but the crack opening will also be reduced. When the crack opening is small, when the water-sand mixture migrates to the crack entrance, it may cause sand blockage and pressure instantaneous When the water pressure increases, it is necessary to relieve the pressure and flush out the clogged area by injecting water, which reduces the work efficiency.
  • the high-pressure end rotating mechanism of the sand injection pump drives the screw to propel the rotating shaft to carry the proppant to the high-pressure fluid, forming a water-proppant solid-liquid two-phase mixed liquid.
  • the rotational speed of the screw propelling shaft is changed. , a certain amount of proppant is carried to the fluid mixing inlet end of the sand injection pump through the screw propelling the rotating shaft and mixed with the liquid phase to form a water-proppant solid-liquid two-phase mixed fluid.
  • the sand injection amount corresponding to each rotational speed is monitored, the sand injection amount at each rotational speed and the time required for the complete injection of sand in the high-pressure sand tank are calibrated, and the solid-liquid two-phase flow is quantitatively controlled by adjusting the rotational speed underground. proppant concentration.
  • the fluid flow and pressure in the high-pressure hose and the amount of sand in the high-pressure sand tank are monitored in real time by the measuring and control instrument. If the pressure in the high-pressure hose is higher than the maximum pressure of the fracturing-sand injection system, the high-pressure pump/pulse pump and sand injection are stopped. pump, and relieve the pressure on the pipeline; when the pressure suddenly increases rapidly during sand injection, it indicates that sand blockage may occur in the pipeline, and sand injection needs to be stopped.
  • the device of the present invention is designed to connect a high-pressure pump or a pulse pump to a high-pressure sand injection system to realize an integrated structure and construction method of post-mixed fracturing and proppant (sand) injection in underground mines.
  • This system realizes continuous sand injection and high-pressure fracturing through high-pressure pump outlet valve, pulse pump outlet valve, fluid mixing inlet valve, mixed fluid outlet valve, pressure balance valve, low-pressure sand adding valve, and high-pressure sand adding valve.
  • Fracturing-sand injection methods such as pulse sand injection for fracturing, multi-particle size and multi-type sand injection for high-pressure fracturing, continuous sand injection for pulse fracturing, pulse sand injection for pulse fracturing, and multi-particle size and multi-type sand injection for pulse fracturing can be used It meets various demands for fracturing sand injection methods in underground mines and has universal applicability.
  • This system uses measurement and control instruments to real-time monitor the flow, pressure, and sand volume in the sand tank during the fracturing and sand adding process, and can provide real-time warning of the situation in the pipeline. If the pipeline/crack is blocked by sand, the pump can be stopped immediately. This ensures the safety of the fracturing-sand injection process.
  • This system provides the capacity guidelines of high-pressure sand tanks, which can realize continuous sand injection, pulse sand injection, multi-particle size and multi-type sand injection and other processes through different sand tank capacities.
  • the horizontal sand injection system of this system can back-calculate the sand content in the high-pressure sand tank by monitoring the weight change of the sand injection system, and correct the high-pressure sand through the relationship between the viscosity of the mixture in the high-pressure sand tank and the proppant concentration.
  • the sand content in the tank is finally displayed in real time by the measurement and control instrument; the vertical sand injection system can control the sand concentration through the speed of the screw.
  • the sand injection pump of this system separates the screw propelling shaft from the high-pressure end rotating mechanism.
  • the screw propelling shaft and the high-pressure end rotating mechanism are magnetically coupled through the large magnetic rotating mechanism to achieve rotational propulsion and sand delivery, effectively solving the problem of the screw propelling shaft and the high-pressure end rotating mechanism.
  • the connection sealing problem of the high-pressure end rotating mechanism is a problem of the high-pressure end rotating mechanism.
  • This system provides an alternating process of fracturing and sand injection.
  • When draining water open the pressure relief valve of the high-pressure hose.
  • valve open the fluid mixing inlet valve, pressure balance valve, high-pressure sand adding valve, and mixed fluid outlet valve, and then perform the sand injection process.
  • Figure 1 is a schematic structural diagram of the integrated device for underground fracturing and proppant injection (horizontal type) of the present invention
  • Figure 2 is a schematic structural diagram of the integrated device for underground fracturing and proppant injection (vertical) in the mine according to the present invention
  • an integrated device for underground fracturing and proppant injection in a mine includes a fracturing system and a proppant injection system.
  • the fracturing system includes a high-pressure pump 1 or a high-pressure hose 10 connected end to end.
  • the high-pressure hose 10 is connected to the high-pressure pump outlet valve 3 or the pulse pump outlet valve 4, and is sequentially connected to the fracturing valve 25, the high-pressure hose pressure relief valve 17, the flow sensor 6, and the pressure sensor 7 through the tee 5; proppant is injected
  • the system includes a pressure balance valve 8 connected end to end by a rigid high-pressure pipe 19, a high-pressure sand tank pressure relief valve 29, a low-pressure sand adding port 12, a low-pressure sand adding valve 11, a high-pressure sand tank 13, a high-pressure sand adding valve 14 and a sand injection pump.
  • the sand injection pump 15 is connected with a fluid mixing inlet valve 9 and a mixed fluid outlet valve 16, in which the pressure balance valve 8 and the fluid mixing inlet valve 9 are connected through high-pressure glue.
  • the pipe 10 is connected to the fracturing system, and the mixed fluid outlet valve 16 is connected to the high-pressure hose pressure relief valve 17 through the high-pressure hose 10; the flow sensor 6, the pressure sensor 7 and the high-pressure sand tank 13 pass through the flow measuring line 21 and the pressure measuring line respectively. 22 and the sand measurement line 20 are connected to the measurement and control instrument 18.
  • the proppant injection system is either vertical or horizontal.
  • the high-pressure sand tank 13 is provided with a stirring device 30.
  • the sand injection pump 15 includes a high-pressure end rotating mechanism and a screw propelling mechanism.
  • the high-pressure end rotating mechanism controls the rotation of the screw propelling mechanism through the magnetic coupling of the large magnetic rotating mechanism.
  • the fracturing valve 25, the high-pressure hose pressure relief valve 17, and the high-pressure pump outlet valve 3 are high-pressure and wear-resistant ball valves.
  • the high-pressure seal installation rod 24 and the hole sealer 26 are hollow high-pressure resistant rods.
  • Flow sensor 6 and pressure sensor 7 are high pressure resistant sensors.
  • the construction process of the integrated device is:
  • Installation and drilling 1 Use a crawler drill to drill holes in the coal seam. The drilling depth should be greater than 20m to avoid penetration of fracturing cracks into the tunnel; 2 Connect the hole sealer 26, high-pressure seal installation rod 24, and high-pressure seal installation rod joint 23 and high-pressure hose 10 are connected and sealed in sequence through threads; 3 Connect the pressure sensor 7, flow sensor 6, high-pressure hose pressure relief valve 17, tee 5, fracturing valve 25, mixed fluid outlet valve 16, fluid mixing inlet valve 9, pressure Balance valve 8, high-pressure pump outlet valve 3 and pulse pump outlet valve 4 are connected through high-pressure hose 10; 4 Connect high-pressure pump outlet valve 3 to high-pressure pump 1, and pulse pump outlet valve 4 to pulse pump 2; 5 Connect the pressure balance valve 8 is connected to the low-pressure sand adding valve 11 and the high-pressure sand tank 13 through the rigid high-pressure pipe 19.
  • the low-pressure sand adding valve 11 is connected to the low-pressure sand adding port 12 through the rigid high-pressure pipe 19.
  • the high-pressure sand tank 13 is connected to the high-pressure sand adding valve 14 and is connected to the high-pressure sand adding valve 14 through the rigid high-pressure pipe 19.
  • the high-pressure pipe 19 is connected to the sand injection pump 15; 6
  • the sand injection pump 15 is connected between the fluid mixing inlet valve 9 and the mixed fluid outlet valve 16.
  • Tee 5, fracturing valve 25, flow sensor 6, pressure sensor 7, high-pressure seal installation rod joint 23, high-pressure seal installation rod 24, and hole sealer 26 reach the fracturing position, and the high-pressure water interacts with the borehole wall and forms a Fracturing cracks form on the borehole wall. With the continuous injection of high-pressure water, the cracks expand and extend to form a hydraulic fracture network. 2Pulse fracturing. Close the fluid mixing inlet valve 9, the mixed fluid outlet valve 16, the pressure balance valve 8, the high-pressure sand tank pressure relief valve 29, the high-pressure pump outlet valve 3, the low-pressure sand adding valve 11, the high-pressure sand adding valve 14, and open the fracturing valve 25, Pulse pump outlet valve 4.
  • the fluid is injected into the hole sealer 26 through the high-pressure thin hose 27 through the hand pump 28, so that the hole sealer 26 expands and seals the hole, and then pulse water is injected through the pulse pump 2, and the pulse water passes through the high-pressure hose 10 and the pulse pump outlet valve in sequence. 4. Tee 5. Fracturing valve 25. Flow sensor 6. Pressure sensor 7. High-pressure seal mounting rod joint 23. When the high-pressure seal installation rod 24 and hole sealer 26 reach the fracturing position, the pulse water interacts with the borehole wall and forms a damage crack zone on the borehole wall. With the continuous injection of pulse water, the damage crack zone expands and extends to form a pulse hydraulic crack. network. After fracturing, turn off the high-pressure pump 1 or pulse pump 2, and relieve pressure on the pipeline through the high-pressure hose pressure relief valve 17. When the pressure reaches 0.5 to 1.0 MPa, stop pressure relief and the fracturing ends.
  • the high-pressure water discharged by the high-pressure pump 1 or the pulse water discharged by the pulse pump 2 after passing through the fluid mixing inlet valve 9, enters the screw propulsion mechanism of the sand injection pump 15, and is mixed with the proppant carried by the screw propulsion mechanism to form water-support
  • the solid-liquid two-phase fluid enters the pressure through the mixed fluid outlet valve 16, the high-pressure hose 10, the flow sensor 6, the pressure sensor 7, the high-pressure seal installation rod joint 23, the high-pressure seal installation rod 24, and the hole sealer 26. crack-sand injection point, and then enter the fracture network formed by fracturing.
  • Sand injection process 1Continuous sand injection.
  • time for the water-proppant solid-liquid mixture to be injected into the fracture network exceeds twice the fracturing time or the proppant in the high-pressure sand tank 13 is completely injected into the fractures, stop injecting the water-proppant solid-liquid mixture into the fractures and inject
  • the sand is finished, turn off the high-pressure pump 1 or pulse pump 2, turn off the sand injection pump 15, and open the high-pressure hose pressure relief valve 17 to relieve the pressure on the fracturing-sand injection system.
  • the pressure is low or the high-pressure hose pressure relief valve 17 no longer sprays
  • the first proppant is injected into the fracture.
  • Turn off the high-pressure pump 1 or pulse pump 2 turn off the sand injection pump 15, open the high-pressure hose pressure relief valve 17 to relieve pressure on the fracturing-sand injection system, close the pressure balance valve 8 and the high-pressure sand adding valve 14, and slowly open the high-pressure sand tank to unload.
  • the pressure valve 29 relieves the pressure in the high-pressure sand tank area.
  • the sand content in the high-pressure sand tank can be back-calculated by monitoring the weight change of the sand injection system, and the high-pressure sand tank can be corrected through the relationship between the viscosity of the mixture in the high-pressure sand tank and the proppant concentration.
  • the amount of sand is finally displayed in real time through the measurement and control instrument.
  • the dynamic viscosity of a two-phase mixture is not easy to obtain. According to experience and analysis, the viscosity ⁇ h of the mixture is a function of the dispersion volume fraction, which can be expressed as
  • the default value is 0.62 for particles and 1 for droplets/bubbles.

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  • Geology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • Physics & Mathematics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
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  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
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Abstract

矿井下压裂及注支撑剂一体化装置及施工方法被公开，装置包括压裂系统和注支撑剂系统。装置实现了高压压裂连续注砂、高压压裂脉冲注砂、高压压裂多粒径多类型注砂、脉冲压裂连续注砂、脉冲压裂脉冲注砂、脉冲压裂多粒径多类型注砂等压裂-注砂方法，可满足矿井下对压裂注砂方式的多种需求，具有普适性。

Description

矿井下压裂及注支撑剂一体化装置及施工方法 技术领域
本发明属于采矿工程技术领域，涉及压裂-注支撑剂设备，具体为矿井下压裂及注支撑剂一体化装置及施工方法。
背景技术
煤层气主要成分为甲烷，每单位燃烧后释放的CO2比煤、石油少，且不产生灰烬，不释放毒素，是一种较清洁能源。同时，开采煤层气，除了提供经济价值外，还降低了煤层甲烷含量、煤层内气体压力，大幅度降低煤与瓦斯突出、瓦斯爆炸事故发生的概率，有效保障煤矿安全高效生产。这些优势使煤层气有望成为未来能源结构的重要组成部分。
然而，我国86％煤层都属于低透气性煤层，渗透率一般介于0.052～1.120mD，煤层气开采较为困难，常采用水力压裂、CO2相变致裂、氮气致裂等方式改造煤层，激活主裂缝两侧的层理与割理，形成相互贯穿的复杂裂缝网络体系，增加煤层内部空隙率，提升其渗透性。压裂还改变了煤层裂缝区域应力分布，打破煤层气的吸附解析平衡状态，使吸附气体变为游离态，易于煤层气抽采。压裂的关键是能否形成具有较高导流能力的裂缝。然而，在闭合应力作用下，裂缝易于闭合，因此在压裂施工过程中，为保证泵注停止和返排后裂缝处于张开状态，需要在压裂液中加入支撑剂支撑裂缝，维持裂缝的导流能力。
目前常用的压裂注砂方式主要分为地面压裂注砂和井下压裂注砂两种，其中，地面压裂注砂已经较为成熟，瓦斯抽采浓度较高，但是随着埋深增加，支撑剂运移距离较远，易出现砂堵现象，且瓦斯抽采成本较高；然而，目前由于井下作业空间有限，环境适应性要求较高，缺少井下压裂注砂设备，瓦斯抽采效率较低，有效抽采时间较短。
发明内容
解决的技术问题：为了克服现有技术的不足，提供一种能够适应矿井下工作环境，实现井下压裂-注砂一体化，实现连续/脉冲/多粒径多类型等多方式注砂，从而适用于井下注砂的多种环境需求，在压裂裂缝内形成最优的支撑剂分布方式，保证裂缝长时有效导流能力，增加瓦斯有效抽采时间，提高瓦斯抽采效率；鉴于此，本发明提供了矿井下压裂及注支撑剂一 体化装置及施工方法。
技术方案：目前常用的压裂方法有常规压裂和脉冲压裂两种方法，常规压裂采用高压大流量泵向储层注入压裂液，储层中易形成主要水力裂缝，产生局部应力集中，分支裂缝较少。与常规压裂相比，脉冲压裂通过脉冲循环泵注，在高频脉冲水压力作用下，使煤体疲劳破坏，产生不受地应力控制的多个方向上的水力裂缝，同时高频脉冲水压冲击煤体，容易激活煤体原生裂缝，使得水力裂缝与天然裂缝沟通，形成复杂的裂缝网路。两种压裂方式均可用于储层增透，常规压裂形成的裂缝长，脉冲压裂形成的裂缝多。
连续注砂在裂缝内的支撑剂分布较为密集，裂缝的闭合速率较低，但是由于支撑剂占据的裂缝空间较大，导流能力相对较低；脉冲注砂在裂缝内的支撑剂呈柱状分布，裂缝的导流能力较高，但是未支撑区域的裂缝闭合速率较高，需合理控制支撑剂间距，使支撑剂柱之间的裂缝在闭合应力作用下依旧存在流体通道；多粒径多类型注砂可针对不同裂缝区域给定合理的支撑剂粒径和类型，例如在裂缝尖端需要小粒径高强度的支撑剂，中间段裂缝区域需要较大粒径或多粒径混合支撑剂，提高支撑剂区域的孔隙，而在裂缝入口位置应注入大粒径支撑剂防止在排采时小粒径支撑剂从裂缝内运移到钻孔内部，但是多粒径多类型注砂工艺较复杂。因此，在不同的储层地质条件和工作环境可采用不同的压裂方法和注砂方法。
矿井下压裂及注支撑剂一体化装置，所述装置包括压裂系统和注支撑剂系统，压裂系统包括由高压胶管首尾依次连接的高压泵或脉冲泵、高压密封安装杆接头、高压密封安装杆、封孔器、高压细软管和手压泵，其中高压泵或脉冲泵与高压密封安装杆接头之间经高压胶管连接有高压泵出口阀或脉冲泵出口阀，并通过三通顺次与压裂阀、高压胶管卸压阀、流量传感器、压力传感器连接；注支撑剂系统包括由刚性高压管首尾依次连接的压力平衡阀、高压砂罐卸压阀、低压加砂口、低压加砂阀、高压砂罐、高压加砂阀和注砂泵，注砂泵上连接有流体混合入口阀和混合流体出口阀，其中压力平衡阀和流体混合入口阀通过高压胶管接入压裂系统，混合流体出口阀通过高压胶管与高压胶管卸压阀连接；所述流量传感器、压力传感器和高压砂罐分别通过流量测线、压力测线和砂量测线与测控仪连接。
优选的，注支撑剂系统为立式或卧式。所述的立式注砂系统包括高压端旋转机构和螺杆推进机构，高压端旋转机构通过大磁力旋转机构的磁力耦合控制螺杆推进机构旋转，在安全要求较高或对高度要求较高的条件下，可将电机采用卧式，螺杆推进机构采用立式，电机通过转向机构(例如转向齿轮)控制高压端旋转机构的旋转，螺杆推进机构进入高压砂罐内部一定高度，防止支撑剂在高压砂罐底部堵塞。
优选的，高压砂罐内设有搅拌装置。
优选的，注砂泵包括高压端旋转机构和螺杆推进机构，高压端旋转机构通过大磁力旋转 机构的磁力耦合控制螺杆推进机构旋转。
优选的，压裂阀、高压胶管卸压阀、高压泵出口阀为抗高压耐磨球阀。
优选的，高压密封安装杆和封孔器为中空抗高压杆。
优选的，流量传感器和压力传感器是抗高压传感器。
以上任一所述矿井下压裂及注支撑剂一体化装置的施工方法，所述方法包括以下步骤：
S1、安装及钻孔
a、通过履带钻机在煤层钻孔，钻孔深度大于20m，避免压裂裂缝与巷道贯穿；
b、将封孔器、高压密封安装杆、高压密封安装杆接头和高压胶管依次通过螺纹连接并密封；
c、将压力传感器、流量传感器、高压胶管卸压阀、三通、压裂阀、混合流体出口阀、流体混合入口阀、压力平衡阀、高压泵出口阀和脉冲泵出口阀通过高压胶管连接；
d、将高压泵出口阀与高压泵连接，脉冲泵出口阀与脉冲泵连接；
e、将压力平衡阀通过刚性高压管与低压加砂阀和高压砂罐连接，低压加砂阀通过刚性高压管与低压加砂口连接，高压砂罐连接高压加砂阀并通过刚性高压管连接到注砂泵；
f、注砂泵连接在流体混合入口阀和混合流体出口阀之间；
S2、压裂
a、高压压裂，关闭流体混合入口阀、混合流体出口阀、压力平衡阀、高压砂罐卸压阀、脉冲泵出口阀、低压加砂阀、高压加砂阀，打开压裂阀、高压泵出口阀，通过手压泵将流体经过高压细软管注入到封孔器，使封孔器膨胀封孔，再通过高压泵注入高压水，高压水依次经过高压胶管、高压泵出口阀、三通、压裂阀、流量传感器、压力传感器、高压密封安装杆接头、高压密封安装杆、封孔器到达压裂位置，高压水与钻孔壁面作用并在钻孔壁面形成压裂裂缝，随着高压水的持续注入，裂缝扩展延伸形成水压裂缝网络；
b、脉冲压裂，关闭流体混合入口阀、混合流体出口阀、压力平衡阀、高压砂罐卸压阀、高压泵出口阀、低压加砂阀、高压加砂阀，打开压裂阀、脉冲泵出口阀，通过手压泵将流体经过高压细软管注入到封孔器，使封孔器膨胀封孔，再通过脉冲泵注入脉冲水，脉冲水依次经过高压胶管、脉冲泵出口阀、三通、压裂阀、流量传感器、压力传感器、高压密封安装杆接头、高压密封安装杆、封孔器到达压裂位置，脉冲水与钻孔壁面作用并在钻孔壁面形成损伤裂缝带，随着脉冲水的持续注入，损伤裂缝带扩展延伸形成脉冲水压裂缝网络，压裂结束后，关闭高压泵或脉冲泵，通过高压胶管卸压阀对管路进行卸压，当压力达到0.5～1.0MPa时，停止卸压，压裂结束；
S3、水-支撑剂固液混合液注入裂缝网络
a、关闭压裂阀、高压胶管卸压阀、高压砂罐卸压阀，打开压力平衡阀、流体混合入口阀、混合流体出口阀、高压加砂阀，打开高压泵或脉冲泵，打开注砂泵，开启搅拌装置，将高压砂罐内的支撑剂搅拌均匀；
b、由高压泵排出的高压水或脉冲泵排出的脉冲水，在经过流体混合入口阀后，进入到注砂泵螺杆推进机构，与螺杆推进机构携带的支撑剂混合为水-支撑剂固液两相流体，两相流体依次通过混合流体出口阀、高压胶管、流量传感器、压力传感器、高压密封安装杆接头、高压密封安装杆、封孔器进入到压裂-注砂点，之后进入已压裂形成的裂缝网络；
S4、注砂工艺
a、连续注砂，当水-支撑剂固液混合液注入裂缝网络的时间超过压裂时长的2倍或者高压砂罐内的支撑剂完全注入裂缝内，停止向裂缝内注入水-支撑剂固液混合流体，注砂结束，关闭高压泵或脉冲泵，关闭注砂泵，打开高压胶管卸压阀对压裂-注砂系统卸压，当压力小于0.5MPa或高压胶管卸压阀处不再喷高压水时，停止卸压，关闭搅拌装置；
b、脉冲注砂，当水-支撑剂固液混合液注入量达到设定值时，停止向裂缝内注入水-支撑剂固液混合流体，第一次注砂结束，关闭压力平衡阀和高压加砂阀，仅向裂缝内注高压水或脉冲水，高压水或脉冲水将已注入裂缝内的支撑剂向前推进冲散，使其呈柱状分布，裂缝导流能力高，高压水或脉冲水注入一段时间后，打开压力平衡阀和高压加砂阀，在裂缝内注入一段支撑剂，之后再注入一段高压水或脉冲水，以此往复，直至高压砂罐内的砂量完全注入裂缝内，完成脉冲注砂工艺；
c、多粒径多类型注砂，当水-支撑剂固液混合液注入裂缝网络的时间超过压裂时长的2倍或者高压砂罐内的支撑剂完全注入裂缝时，停止向裂缝内注入水-支撑剂固液混合流体，完成第一种支撑剂注入裂缝，关闭高压泵或脉冲泵，关闭注砂泵，打开高压胶管卸压阀对压裂-注砂系统卸压，关闭压力平衡阀、高压加砂阀，缓慢打开高压砂罐卸压阀对高压砂罐区域进行卸压，当不再喷高压水，关闭高压砂罐卸压阀，打开低压加砂阀，通过低压加砂口对高压砂罐补充不同粒径或不同类型或混合型的支撑剂，当支撑剂填充满时，关闭低压加砂阀、打开高压加砂阀和压力平衡阀，重复步骤c再次进行加砂，以此往复，直到完成全部类型、粒径、混合的注砂流程；
S5、注砂过程中异常监测
当测控仪显示出现异常压力时，此时应关闭压力平衡阀和高压加砂阀，仅向裂缝内注入高压水或脉冲水，由高压水或脉冲水将砂堵区间冲开，当测控仪监测的压力不再异常时，再打开压力平衡阀和高压加砂阀进行注砂；
S6、注顶替液
当向裂缝内注入水-支撑剂固液混合液结束后，再向裂缝内注入3～5min的高压水，使管路内及近孔口区域的支撑剂向裂缝内部运移；
S7、卸压撤杆
a、关闭注砂泵，关闭高压泵或脉冲泵，通过高压胶管卸压阀对管路进行卸压，当压力小于0.5MPa或不再喷高压水时，再卸压3～5min，保证管路内的压力完全卸除；
b、将高压胶管从高压密封安装杆接头拆除，待高压密封安装杆接头不再出水或水量极小时，通过手压泵对封孔器卸压；
S8、瓦斯抽采
将高压密封安装杆与封孔器撤出钻孔，接上抽采管路对该区域煤层进行瓦斯抽采；
将矿井下压裂及注支撑剂一体化装置移动到下一个钻孔，重复步骤S1-S8，实现整个工作面或指定区域的卸压抽采。
本发明所述方法包括高压压裂连续注砂、高压压裂脉冲注砂、高压压裂多粒径多类型注砂、脉冲压裂连续注砂、脉冲压裂脉冲注砂、脉冲压裂多粒径多类型注砂等压裂-注砂方法。所述的高压压裂连续注砂是通过高压泵压裂后在压裂缝网内连续注入支撑剂的方法；所述的高压压裂脉冲注砂是通过高压泵压裂后在压裂缝网内间断脉冲注入支撑剂的方法；所述的高压压裂多粒径多类型注砂是通过高压泵压裂后在压裂缝网内依次注入不同粒径支撑剂或不同类型支撑剂或多粒径多类型混合支撑剂的方法；所述的脉冲压裂连续注砂是通过脉冲泵压裂后在压裂缝网内连续注入支撑剂的方法；所述的脉冲压裂脉冲注砂是通过脉冲泵压裂后在压裂缝网内间断脉冲注入支撑剂的方法；所述的脉冲压裂多粒径多类型注砂是通过脉冲泵压裂后在压裂缝网内依次注入不同粒径支撑剂或不同类型支撑剂或多粒径类型混合支撑剂的方法。
本发明所述一体化装置克服的技术难点及工作原理在于：
1.压裂-注砂系统密封
注砂泵将螺杆推进转轴与高压端旋转机构分离，将螺杆推进转轴与高压端旋转机构通过大磁力旋转机构的磁力耦合实现旋转推进送砂，有效解决了螺杆推进转轴与高压端旋转机构的连接密封问题。
2.注砂过程中的压力平衡
在注砂时，如果高压砂罐和注砂泵区域形成一个封闭空间，在高压水经过流体混合入口进入注砂泵时，会在致使高压砂罐和注砂泵的封闭空间形成高负压吸力，为避免高压砂罐和注砂泵在高负压下变形，砂罐的强度和刚度需要提高，同时由于没有压力平衡系统，高压砂罐内的支撑剂无法进入液相形成固液混合流体，不能达到支撑剂运移到裂缝内的要求。为避 免高负压对支撑剂运移和设备强度的影响，在砂罐上口设置压力平衡阀，通过在高压砂罐上方注入与管路内近似同压力的流体，和支撑剂的自重，将高压砂罐内的支撑剂携带进入注砂泵的螺旋推进机构，通过螺旋推进机构将支撑剂运输到螺旋推进机构流体混合入口端，与液相汇合过程流固两相汇合流体，在液相流体携带下将支撑剂运输到裂缝内。
3.注砂过程中的颗粒运移
在采用卧式注砂系统注砂时，高压砂罐内的支撑剂在水压力和自重作用下向螺杆推进装置内部运移，在支撑剂运移过程中可能会使支撑剂在高压加砂阀近高压砂罐段堵塞，致使注砂泵螺杆旋转推进转轴左右两端压差较大，对螺杆旋转推进转轴磨损增加，因此需在高压砂罐内连接高压搅拌装置，使高压砂罐内的支撑剂分布相对均匀，同时避免在高压砂罐近高压加砂阀位置形成砂堵。
4.砂罐体积匹配准则
在压裂注砂系统中，高压砂罐内支撑剂容量是影响压裂注砂工艺流程的关键因素。当在支撑剂补充时，需将压裂-注砂系统内的压力调节到较小范围，若压裂-注砂系统内的压力处于高压状态，若操作失误将导致低压注砂端喷砂，对周围设备等存在潜在危险。因此需停止高压/脉冲泵后，将压裂-注砂系统内的高压通过高压胶管卸压阀卸除，之后在低压加砂口补充砂量，将砂罐填充满后，进行再次注砂。如果高压砂罐的体积太小，将需要多次补充支撑剂，这将会导致注砂操作复杂，工艺繁琐，效率较低。然而，若高压砂罐体积太大，将会占用较大的空间，而井下巷道内的作业空间有限，故高压砂罐的体积不宜过大。为使高压砂罐既可以满足巷道空间要求又可以减少注砂次数，需合理的设计高压砂罐的容量。现给出高压砂罐设计的原则：①在连续注砂时，高压砂罐内的支撑剂容量应高于单次加砂量的一半，使其最多两次完成一个压裂点的注砂；②在脉冲注砂时，高压砂罐内的支撑剂容量应大于单次加砂量，达到一次加砂完成一个压裂点的注砂；③在多粒径多类型注砂时，高压砂罐内的支撑剂容量应保证每个压裂点每种单一粒径、单一类型或混合粒径都可以单次注完；④由于高压砂罐通过刚性管连接到注砂泵，因此高压砂罐装满支撑剂后的重量应保证对注砂泵的运行影响较小；⑤由于井下作业空间有限，所以高压砂罐与注砂泵的整体的高度应小于1.2m，便于在井下放置注砂泵，同时便于加砂工作。
5.压裂与注砂交替的过程
通过高压泵或脉冲泵注水在煤储层内压裂形成缝网后，由于管路内的高压致使压力平衡阀、流体混合入口阀、高压加砂阀、混合流体出口阀、压裂阀等阀门打开较困难，所以需要对管路内进行初步卸压。如果将管路内的水全部排出，不仅排水时间较长，还会致使裂缝张开度降低。裂缝张开度较小时，当水砂混合液运移到裂缝入口，可能会导致堵砂，压力瞬间 增高，需要卸压通过注水将堵塞区域冲开，工作效率降低，因此，在排水时，打开高压胶管卸压阀，当管路内水压力在0.5～1.0MPa时，停止卸压，在低压下关闭压裂阀，打开流体混合入口阀、压力平衡阀、高压加砂阀、混合流体出口阀，再进行注砂工艺。
6.注砂量的控制方法
注砂通过注砂泵的高压端旋转机构带动螺杆推进转轴将支撑剂携带到高压流体，形成水-支撑剂固液两相混合液体，通过控制高压端旋转机构的转速，改变螺杆推进转轴的转速，通过螺杆推进转轴将定量的支撑剂携带到注砂泵流体混合入口端与液相混合形成水-支撑剂固液两相混合流体。在出厂时通过监测各个转速对应的注砂量，标定各转速下的注砂量和高压砂罐内砂量完全注完所需的时间，在井下通过调整转速实现定量控制固液两相流内的支撑剂浓度。
7.管路内预警
通过测控仪实时监测高压胶管内的流体流量和压力以及高压砂罐中的砂量，若高压胶管内的压力高于压裂-注砂系统的最大压力时，停止高压泵/脉冲泵和注砂泵，并对管路进行卸压；当注砂时压力突然快速增加时，表明管路内可能出现砂堵，需停止注砂，仅通过高压泵/脉冲泵注水将砂堵部分冲开，之后再次进行注砂；当砂罐内的砂量显示注完后，再注水3～5min，保证管路内的支撑剂全部压裂裂缝网络，并为返排提供有效空间，同时在卸压时要缓慢，防止返排时将支撑剂携带出裂缝。
有益效果：
1.本发明所述装置设计了高压泵或脉冲泵连接高压注砂系统，实现矿井下后混式压裂-注支撑剂(砂)一体化结构及施工方法。
2.本套系统通过高压泵出口阀、脉冲泵出口阀、流体混合入口阀、混合流体出口阀、压力平衡阀、低压加砂阀、高压加砂阀，实现了高压压裂连续注砂、高压压裂脉冲注砂、高压压裂多粒径多类型注砂、脉冲压裂连续注砂、脉冲压裂脉冲注砂、脉冲压裂多粒径多类型注砂等压裂-注砂方法，可满足矿井下对压裂注砂方式的多种需求，具有普适性。
3.本套系统通过测控仪实时监控压裂-加砂过程中的流量、压力、砂罐砂量，可对管路内情况实时预警，若管路/裂缝内砂堵，可立刻停泵，保证了压裂-注砂过程的安全。
4.本套系统给出了高压砂罐的容量准则，可通过不同的砂罐容量实现连续注砂、脉冲注砂、多粒径多类型注砂等工艺。
5.本套系统卧式注砂系统可通过监测注砂系统的重量变化来反算高压砂罐内的含砂量，通过高压砂罐内的混合物粘度与支撑剂浓度间的关系式修正高压砂罐内的含砂量，最终通过测控仪实时显示注砂量；立式注砂系统可通过螺杆的转速控制加砂浓度。
6.本套系统的注砂泵将螺杆推进转轴与高压端旋转机构分离，将螺杆推进转轴与高压端旋转机构通过大磁力旋转机构的磁力耦合实现旋转推进送砂，有效解决了螺杆推进转轴与高压端旋转机构的连接密封问题。
7.本套系统给出了压裂与注砂交替过程，在排水时，打开高压胶管卸压阀，当管路内水压力在0.5～1.0MPa时，停止卸压，在低压下关闭压裂阀，打开流体混合入口阀、压力平衡阀、高压加砂阀、混合流体出口阀，再进行注砂工艺。
附图说明
图1是本发明矿井下压裂及注支撑剂(卧式)一体化装置结构示意图；
图2是本发明矿井下压裂及注支撑剂(立式)一体化装置结构示意图；
图中，1、高压泵，2、脉冲泵，3、高压泵出口阀，4、脉冲泵出口阀，5、三通，6、流量传感器，7、压力传感器，8、压力平衡阀，9、流体混合入口阀，10、高压胶管，11、低压加砂阀，12、低压加砂口，13、高压砂罐，14、高压加砂阀，15、注砂泵，16、混合流体出口阀，17、高压胶管卸压阀，18、测控仪，19、刚性高压管，20、砂量测线，21、流量测线，22、压力测线，23、高压密封安装杆接头，24、高压密封安装杆，25、压裂阀，26、搅拌装置，27、高压细软管，28、手压泵，29、高压砂罐卸压阀，30、搅拌装置。
具体实施方式
以下实施例进一步说明本发明的内容，但不应理解为对本发明的限制。在不背离本发明精神和实质的情况下，对本发明方法、步骤或条件所作的修改和替换，均属于本发明的范围。若未特别指明，实施例中所用的技术手段为本领域技术人员所熟知的常规手段。
实施例1
如图1或图2所示，矿井下压裂及注支撑剂一体化装置，所述装置包括压裂系统和注支撑剂系统，压裂系统包括由高压胶管10首尾依次连接的高压泵1或脉冲泵2、高压密封安装杆接头23、高压密封安装杆24、封孔器26、高压细软管27和手压泵28，其中高压泵1或脉冲泵2与高压密封安装杆接头23之间经高压胶管10连接有高压泵出口阀3或脉冲泵出口阀4，并通过三通5顺次与压裂阀25、高压胶管卸压阀17、流量传感器6、压力传感器7连接；注支撑剂系统包括由刚性高压管19首尾依次连接的压力平衡阀8、高压砂罐卸压阀29、低压加砂口12、低压加砂阀11、高压砂罐13、高压加砂阀14和注砂泵15，注砂泵15上连接有流体混合入口阀9和混合流体出口阀16，其中压力平衡阀8和流体混合入口阀9通过高压胶 管10接入压裂系统，混合流体出口阀16通过高压胶管10与高压胶管卸压阀17连接；所述流量传感器6、压力传感器7和高压砂罐13分别通过流量测线21、压力测线22和砂量测线20与测控仪18连接。
注支撑剂系统为立式或卧式。
高压砂罐13内设有搅拌装置30。
注砂泵15包括高压端旋转机构和螺杆推进机构，高压端旋转机构通过大磁力旋转机构的磁力耦合控制螺杆推进机构旋转。
压裂阀25、高压胶管卸压阀17、高压泵出口阀3为抗高压耐磨球阀。
高压密封安装杆24和封孔器26为中空抗高压杆。
流量传感器6和压力传感器7是抗高压传感器。
所述一体化装置的施工过程为：
1、安装及钻孔：①通过履带钻机在煤层钻孔，钻孔深度应大于20m，避免压裂裂缝与巷道贯穿；②将封孔器26、高压密封安装杆24、高压密封安装杆接头23和高压胶管10依次通过螺纹连接并密封；③将压力传感器7、流量传感器6、高压胶管卸压阀17、三通5、压裂阀25、混合流体出口阀16、流体混合入口阀9、压力平衡阀8、高压泵出口阀3和脉冲泵出口阀4通过高压胶管10连接；④将高压泵出口阀3与高压泵1连接，脉冲泵出口阀4与脉冲泵2连接；⑤将压力平衡阀8通过刚性高压管19与低压加砂阀11和高压砂罐13连接，低压加砂阀11通过刚性高压管19与低压加砂口12连接，高压砂罐13连接高压加砂阀14并通过刚性高压管19连接到注砂泵15；⑥注砂泵15连接在流体混合入口阀9和混合流体出口阀16之间。
2、压裂：①高压压裂。关闭流体混合入口阀9、混合流体出口阀16、压力平衡阀8、高压砂罐卸压阀29、脉冲泵出口阀4、低压加砂阀11、高压加砂阀14，打开压裂阀25、高压泵出口阀3。通过手压泵28将流体经过高压细软管27注入到封孔器26，使封孔器26膨胀封孔，再通过高压泵1注入高压水，高压水依次经过高压胶管10、高压泵出口阀3、三通5、压裂阀25、流量传感器6、压力传感器7、高压密封安装杆接头23、高压密封安装杆24、封孔器26到达压裂位置，高压水与钻孔壁面作用并在钻孔壁面形成压裂裂缝，随着高压水的持续注入，裂缝扩展延伸形成水压裂缝网络。②脉冲压裂。关闭流体混合入口阀9、混合流体出口阀16、压力平衡阀8、高压砂罐卸压阀29、高压泵出口阀3、低压加砂阀11、高压加砂阀14，打开压裂阀25、脉冲泵出口阀4。通过手压泵28将流体经过高压细软管27注入到封孔器26，使封孔器26膨胀封孔，再通过脉冲泵2注入脉冲水，脉冲水依次经过高压胶管10、脉冲泵出口阀4、三通5、压裂阀25、流量传感器6、压力传感器7、高压密封安装杆接头23、 高压密封安装杆24、封孔器26到达压裂位置，脉冲水与钻孔壁面作用并在钻孔壁面形成损伤裂缝带，随着脉冲水的持续注入，损伤裂缝带扩展延伸形成脉冲水压裂缝网络。压裂结束后，关闭高压泵1或脉冲泵2，通过高压胶管卸压阀17对管路进行卸压，当压力达到0.5～1.0MPa时，停止卸压，压裂结束。
3、水-支撑剂固液混合液注入裂缝网络。①关闭压裂阀25、高压胶管卸压阀17、高压砂罐卸压阀29，打开压力平衡阀8、流体混合入口阀9、混合流体出口阀16、高压加砂阀14，打开高压泵1或脉冲泵2，打开注砂泵15，开启搅拌装置30，将高压砂罐13内的支撑剂搅拌均匀。②由高压泵1排出的高压水或脉冲泵2排出的脉冲水，在经过流体混合入口阀9后，进入到注砂泵15螺杆推进机构，与螺杆推进机构携带的支撑剂混合为水-支撑剂固液两相流体，两相流体依次通过混合流体出口阀16、高压胶管10、流量传感器6、压力传感器7、高压密封安装杆接头23、高压密封安装杆24、封孔器26进入到压裂-注砂点，之后进入已压裂形成的裂缝网络。
4、注砂工艺。①连续注砂。当水-支撑剂固液混合液注入裂缝网络的时间超过压裂时长的2倍或者高压砂罐13内的支撑剂完全注入裂缝内，停止向裂缝内注入水-支撑剂固液混合流体，注砂结束，关闭高压泵1或脉冲泵2，关闭注砂泵15，打开高压胶管卸压阀17对压裂-注砂系统卸压，当压力较小或高压胶管卸压阀17处不再喷高压水时，停止卸压，关闭搅拌装置30。②脉冲注砂。当水-支撑剂固液混合液注入量达到设定的第一次脉冲注砂量时，停止向裂缝内注入水-支撑剂固液混合流体，第一次注砂结束。关闭压力平衡阀8和高压加砂阀14，仅向裂缝内注高压水或脉冲水，高压水或脉冲水将已注入裂缝内的支撑剂向前推进冲散，使其呈柱状分布，裂缝导流能力高。高压水或脉冲水注入一段时间后，打开压力平衡阀8和高压加砂阀14，在裂缝内注入一段支撑剂，之后再注入一段高压水或脉冲水，以此往复，直至高压砂罐13内的砂量完全注入裂缝内，完成脉冲注砂工艺。③多粒径多类型注砂。当水-支撑剂固液混合液注入裂缝网络的时间超过压裂时长的2倍或者高压砂罐13内的支撑剂完全注入裂缝时，停止向裂缝内注入水-支撑剂固液混合流体，完成第一种支撑剂注入裂缝。关闭高压泵1或脉冲泵2，关闭注砂泵15，打开高压胶管卸压阀17对压裂-注砂系统卸压，关闭压力平衡阀8、高压加砂阀14，缓慢打开高压砂罐卸压阀29对高压砂罐区域进行卸压，当不再喷高压水，关闭高压砂罐卸压阀29，打开低压加砂阀11，通过低压加砂口12对高压砂罐13补充不同粒径或不同类型或混合型的支撑剂，当支撑剂填充满时，关闭低压加砂阀11、打开高压加砂阀14和压力平衡阀8，重复③再次进行加砂，以此往复，直到完成全部类型、粒径、混合的注砂流程。此外，采用卧式注砂系统时，通过监测注砂系统的重量变化来反算高压砂罐内的含砂量，通过高压砂罐内的混合物粘度与支撑剂浓度间的关系式修正高压砂罐内的含 砂量，最终通过测控仪实时显示注砂量。两相混合物的动态粘度不易获取，根据经验和分析得到混合物粘度μh为分散体积分数的函数，可以表示为
式中，μy是液体的动力粘度，Pa·s；μg是固体的动力粘度，Pa·s；φg是固相的体积分数，无量纲(dimensionless)；φgmax是最大充填限度，固体颗粒默认值为0.62，液滴/气泡默认值为1。
5、注砂过程中异常监测。当测控仪18显示出现异常压力时，可能是裂缝或管路内出现砂堵，此时应关闭压力平衡阀8和高压加砂阀14，仅向裂缝内注入高压水或脉冲水，由高压水或脉冲水将砂堵区间冲开，当测控仪18监测的压力不再异常时，再打开压力平衡阀8和高压加砂阀14进行注砂。
6、注顶替液。当向裂缝内注入水-支撑剂固液混合液结束后，再向裂缝内注入3～5min的高压水，使管路内及近孔口区域的支撑剂向裂缝内部运移。
7、卸压撤杆。①关闭注砂泵15,关闭高压泵1或脉冲泵2，通过高压胶管卸压阀17对管路进行卸压，当压力较小或不再喷高压水时，再卸压3～5min，保证管路内的压力完全卸除。②将高压胶管10从高压密封安装杆接头23拆除，待高压密封安装杆接头23不再出水或水量极小时，通过手压泵28对封孔器26卸压。
8、瓦斯抽采。将高压密封安装杆24与封孔器26撤出钻孔，接上抽采管路对该区域煤层进行瓦斯抽采。
将压裂-注砂系统移动到下一个钻孔，重复第1～8步，实现该工作面或指定区域的卸压抽采。

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  1. 矿井下压裂及注支撑剂一体化装置，其特征在于，所述装置包括压裂系统和注支撑剂系统，压裂系统包括由高压胶管(10)首尾依次连接的高压泵(1)或脉冲泵(2)、高压密封安装杆接头(23)、高压密封安装杆(24)、封孔器(26)、高压细软管(27)和手压泵(28)，其中高压泵(1)或脉冲泵(2)与高压密封安装杆接头(23)之间经高压胶管(10)连接有高压泵出口阀(3)或脉冲泵出口阀(4)，并通过三通(5)顺次与压裂阀(25)、高压胶管卸压阀(17)、流量传感器(6)、压力传感器(7)连接；注支撑剂系统包括由刚性高压管(19)首尾依次连接的压力平衡阀(8)、高压砂罐卸压阀(29)、低压加砂口(12)、低压加砂阀(11)、高压砂罐(13)、高压加砂阀(14)和注砂泵(15)，注砂泵(15)上连接有流体混合入口阀(9)和混合流体出口阀(16)，其中压力平衡阀(8)和流体混合入口阀(9)通过高压胶管(10)接入压裂系统，混合流体出口阀(16)通过高压胶管(10)与高压胶管卸压阀(17)连接；所述流量传感器(6)、压力传感器(7)和高压砂罐(13)分别通过流量测线(21)、压力测线(22)和砂量测线(20)与测控仪(18)连接。
  2. 根据权利要求1所述的矿井下压裂及注支撑剂一体化装置，其特征在于，注支撑剂系统为立式或卧式。
  3. 根据权利要求1所述的矿井下压裂及注支撑剂一体化装置，其特征在于，高压砂罐(13)内设有搅拌装置(30)。
  4. 根据权利要求1所述的矿井下压裂及注支撑剂一体化装置，其特征在于，注砂泵(15)包括高压端旋转机构和螺杆推进机构，高压端旋转机构通过大磁力旋转机构的磁力耦合控制螺杆推进机构旋转。
  5. 根据权利要求1所述的矿井下压裂及注支撑剂一体化装置，其特征在于，压裂阀(25)、高压胶管卸压阀(17)、高压泵出口阀(3)为抗高压耐磨球阀。
  6. 根据权利要求1所述的矿井下压裂及注支撑剂一体化装置，其特征在于，高压密封安装杆(24)和封孔器(26)为中空抗高压杆。
  7. 根据权利要求1所述的矿井下压裂及注支撑剂一体化装置，其特征在于，流量传感器(6)和压力传感器(7)是抗高压传感器。
  8. 权利要求1-7任一所述矿井下压裂及注支撑剂一体化装置的施工方法，其特征在于，所述方法包括以下步骤：
    S1、安装及钻孔
    a、通过履带钻机在煤层钻孔，钻孔深度大于20m，避免压裂裂缝与巷道贯穿；
    b、将封孔器(26)、高压密封安装杆(24)、高压密封安装杆接头(23)和高压胶管(10)依次通过螺纹连接并密封；
    c、将压力传感器(7)、流量传感器(6)、高压胶管卸压阀(17)、三通(5)、压裂阀(25)、混合流体出口阀(16)、流体混合入口阀(9)、压力平衡阀(8)、高压泵出口阀(3)和脉冲泵出口阀(4)通过高压胶管(10)连接；
    d、将高压泵出口阀(3)与高压泵(1)连接，脉冲泵出口阀(4)与脉冲泵(2)连接；
    e、将压力平衡阀(8)通过刚性高压管(19)与低压加砂阀(11)和高压砂罐(13)连接，低压加砂阀(11)通过刚性高压管(19)与低压加砂口(12)连接，高压砂罐(13)连接高压加砂阀(14)并通过刚性高压管(19)连接到注砂泵(15)；
    f、注砂泵(15)连接在流体混合入口阀(9)和混合流体出口阀(16)之间；
    S2、压裂
    a、高压压裂，关闭流体混合入口阀(9)、混合流体出口阀(16)、压力平衡阀(8)、高压砂罐卸压阀(29)、脉冲泵出口阀(4)、低压加砂阀(11)、高压加砂阀(14)，打开压裂阀(25)、高压泵出口阀(3)，通过手压泵(28)将流体经过高压细软管(27)注入到封孔器(26)，使封孔器(26)膨胀封孔，再通过高压泵(1)注入高压水，高压水依次经过高压胶管(10)、高压泵出口阀(3)、三通(5)、压裂阀(25)、流量传感器(6)、压力传感器(7)、高压密封安装杆接头(23)、高压密封安装杆(24)、封孔器(26)到达压裂位置，高压水与钻孔壁面作用并在钻孔壁面形成压裂裂缝，随着高压水的持续注入，裂缝扩展延伸形成水压裂缝网络；
    b、脉冲压裂，关闭流体混合入口阀(9)、混合流体出口阀(16)、压力平衡阀(8)、高压砂罐卸压阀(29)、高压泵出口阀(3)、低压加砂阀(11)、高压加砂阀(14)，打开压裂阀(25)、脉冲泵出口阀(4)，通过手压泵(28)将流体经过高压细软管(27)注入到封孔器(26)，使封孔器(26)膨胀封孔，再通过脉冲泵(2)注入脉冲水，脉冲水依次经过高压胶管(10)、脉冲泵出口阀(4)、三通(5)、压裂阀(25)、流量传感器(6)、压力传感器(7)、高压密封安装杆接头(23)、高压密封安装杆(24)、封孔器(26)到达压裂位置，脉冲水与钻孔壁面作用并在钻孔壁面形成损伤裂缝带，随着脉冲水的持续注入，损伤裂缝带扩展延伸形成脉冲水压裂缝网络，压裂结束后，关闭高压泵(1)或脉冲泵(2)，通过高压胶管卸压阀(17)对管路进行卸压，当压力达到0.5～1.0MPa时，停止卸压，压裂结束；
    S3、水-支撑剂固液混合液注入裂缝网络
    a、关闭压裂阀(25)、高压胶管卸压阀(17)、高压砂罐卸压阀(29)，打开压力平衡阀(8)、流体混合入口阀(9)、混合流体出口阀(16)、高压加砂阀(14)，打开高压泵(1)或脉冲泵(2)，打开注砂泵(15)，开启搅拌装置(30)，将高压砂罐(13)内的支撑剂搅拌均 匀；
    b、由高压泵(1)排出的高压水或脉冲泵(2)排出的脉冲水，在经过流体混合入口阀(9)后，进入到注砂泵(15)螺杆推进机构，与螺杆推进机构携带的支撑剂混合为水-支撑剂固液两相流体，两相流体依次通过混合流体出口阀(16)、高压胶管(10)、流量传感器(6)、压力传感器(7)、高压密封安装杆接头(23)、高压密封安装杆(24)、封孔器(26)进入到压裂-注砂点，之后进入已压裂形成的裂缝网络；
    S4、注砂工艺
    a、连续注砂，当水-支撑剂固液混合液注入裂缝网络的时间超过压裂时长的2倍或者高压砂罐(13)内的支撑剂完全注入裂缝内，停止向裂缝内注入水-支撑剂固液混合流体，注砂结束，关闭高压泵(1)或脉冲泵(2)，关闭注砂泵(15)，打开高压胶管卸压阀(17)对压裂-注砂系统卸压，当压力小于0.5MPa或高压胶管卸压阀(17)处不再喷高压水时，停止卸压，关闭搅拌装置(30)；
    b、脉冲注砂，当水-支撑剂固液混合液注入量达到设定值时，停止向裂缝内注入水-支撑剂固液混合流体，第一次注砂结束，关闭压力平衡阀(8)和高压加砂阀(14)，仅向裂缝内注高压水或脉冲水，高压水或脉冲水将已注入裂缝内的支撑剂向前推进冲散，使其呈柱状分布，裂缝导流能力高，高压水或脉冲水注入一段时间后，打开压力平衡阀(8)和高压加砂阀(14)，在裂缝内注入一段支撑剂，之后再注入一段高压水或脉冲水，以此往复，直至高压砂罐(13)内的砂量完全注入裂缝内，完成脉冲注砂工艺；
    c、多粒径多类型注砂，当水-支撑剂固液混合液注入裂缝网络的时间超过压裂时长的2倍或者高压砂罐(13)内的支撑剂完全注入裂缝时，停止向裂缝内注入水-支撑剂固液混合流体，完成第一种支撑剂注入裂缝，关闭高压泵(1)或脉冲泵(2)，关闭注砂泵(15)，打开高压胶管卸压阀(17)对压裂-注砂系统卸压，关闭压力平衡阀(8)、高压加砂阀(14)，缓慢打开高压砂罐卸压阀(29)对高压砂罐区域进行卸压，当不再喷高压水，关闭高压砂罐卸压阀(29)，打开低压加砂阀(11)，通过低压加砂口(12)对高压砂罐(13)补充不同粒径或不同类型或混合型的支撑剂，当支撑剂填充满时，关闭低压加砂阀(11)、打开高压加砂阀(14)和压力平衡阀(8)，重复步骤c再次进行加砂，以此往复，直到完成全部类型、粒径、混合的注砂流程；
    S5、注砂过程中异常监测
    当测控仪(18)显示出现异常压力时，此时应关闭压力平衡阀(8)和高压加砂阀(14)，仅向裂缝内注入高压水或脉冲水，由高压水或脉冲水将砂堵区间冲开，当测控仪(18)监测的压力不再异常时，再打开压力平衡阀(8)和高压加砂阀(14)进行注砂；
    S6、注顶替液
    当向裂缝内注入水-支撑剂固液混合液结束后，再向裂缝内注入3～5min的高压水，使管路内及近孔口区域的支撑剂向裂缝内部运移；
    S7、卸压撤杆
    a、关闭注砂泵(15)，关闭高压泵(1)或脉冲泵(2)，通过高压胶管卸压阀(17)对管路进行卸压，当压力小于0.5MPa或不再喷高压水时，再卸压3～5min，保证管路内的压力完全卸除；
    b、将高压胶管(10)从高压密封安装杆接头(23)拆除，待高压密封安装杆接头(23)不再出水或水量极小时，通过手压泵(28)对封孔器(26)卸压；
    S8、瓦斯抽采
    将高压密封安装杆(24)与封孔器(26)撤出钻孔，接上抽采管路对该区域煤层进行瓦斯抽采；
    将矿井下压裂及注支撑剂一体化装置移动到下一个钻孔，重复步骤S1-S8，实现整个工作面或指定区域的卸压抽采。
  9. 根据权利要求8所述的矿井下压裂及注支撑剂一体化装置的施工方法，其特征在于，S4注砂工艺中维持装置压力平衡的方法为：注砂时，高压砂罐(13)和注砂泵(15)区域形成封闭空间，在高压水经过流体混合入口进入注砂泵(15)时，会在致使高压砂罐(13)和注砂泵(15)的封闭空间形成高负压吸力，为避免高负压对支撑剂运移和设备强度的影响，在砂罐上口设置压力平衡阀(8)，通过在高压砂罐(13)上方注入与管路内近似同压力的流体，结合支撑剂的自重，将高压砂罐(13)内的支撑剂携带进入注砂泵(15)的螺旋推进机构，通过螺旋推进机构将支撑剂运输到螺旋推进机构流体混合入口端，与液相汇合形成流固两相汇合流体，在液相流体携带下将支撑剂运输到裂缝内。
  10. 根据权利要求8所述的矿井下压裂及注支撑剂一体化装置的施工方法，其特征在于，S4注砂工艺中，维持螺杆推进转轴与高压端旋转机构连接密封的方法为：注砂泵(15)将螺杆推进转轴与高压端旋转机构分离，并将螺杆推进转轴与高压端旋转机构通过大磁力旋转机构的磁力耦合实现旋转推进送砂。
  11. 根据权利要求8所述的矿井下压裂及注支撑剂一体化装置的施工方法，其特征在于，采用卧式注砂系统注砂时，促进注砂过程中颗粒运移的方法为：高压砂罐(13)内连接高压搅拌装置，使高压砂罐(13)内的支撑剂分布相对均匀，同时避免在高压砂罐(13)靠近高压加砂阀(14)位置形成砂堵。
  12. 根据权利要求8所述的矿井下压裂及注支撑剂一体化装置的施工方法，其特征在于，压裂 与注砂交替过程的控制方法为：通过高压泵(1)或脉冲泵(2)注水在煤储层内压裂形成缝网后，需要对管路内进行初步卸压；排水时，打开高压胶管卸压阀(17)，当管路内水压力在0.5～1.0MPa时，停止卸压，在低压下关闭压裂阀(25)，打开流体混合入口阀(9)、压力平衡阀(8)、高压加砂阀(14)、混合流体出口阀(16)，再进行注砂工艺。
  13. 根据权利要求8所述的矿井下压裂及注支撑剂一体化装置的施工方法，其特征在于，砂罐体积匹配的方法为：当在支撑剂补充时，停止高压/脉冲泵后，将压裂-注砂系统内的高压通过高压胶管卸压阀(17)卸除，之后在低压加砂口补充砂量，将砂罐填充满后，进行再次注砂；其中，高压砂罐(13)设计的方法为：①在连续注砂时，高压砂罐(13)内的支撑剂容量高于单次加砂量的一半，使其最多两次完成一个压裂点的注砂；②在脉冲注砂时，高压砂罐(13)内的支撑剂容量大于单次加砂量，达到一次加砂完成一个压裂点的注砂；③在多粒径多类型注砂时，高压砂罐(13)内的支撑剂容量保证每个压裂点每种单一粒径、单一类型或混合粒径都能单次注完；④高压砂罐(13)与注砂泵(15)的整体高度小于1.2m，便于在井下放置注砂泵，同时便于加砂工作。
  14. 根据权利要求8所述的矿井下压裂及注支撑剂一体化装置的施工方法，其特征在于，注砂量控制方法为：通过注砂泵(15)的高压端旋转机构带动螺杆推进转轴将支撑剂携带到高压流体，形成水-支撑剂固液两相混合液体，通过控制高压端旋转机构的转速，改变螺杆推进转轴的转速，通过螺杆推进转轴将定量的支撑剂携带到注砂泵(15)流体混合入口端与液相混合形成水-支撑剂固液两相混合流体；在出厂时通过监测各个转速对应的注砂量，标定各转速下的注砂量和高压砂罐(13)内砂量完全注完所需的时间，在井下通过调整转速实现定量控制固液两相流内的支撑剂浓度。
  15. 根据权利要求8所述的矿井下压裂及注支撑剂一体化装置的施工方法，其特征在于，管路内预警方法为：通过测控仪实时监测高压胶管内的流体流量和压力以及高压砂罐(13)中的砂量，高压胶管内的压力高于压裂-注砂系统的最大压力时，停止高压泵(1)、脉冲泵(2)和注砂泵(15)，并对管路进行卸压；当注砂时压力突然快速增加时，需停止注砂，通过高压泵(1)、脉冲泵(2)注水将砂堵部分冲开，之后再次进行注砂；当砂罐内的砂量显示注完后，再注水3～5min，保证管路内的支撑剂全部压裂裂缝网络。
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