WO2024078506A1 - 一种煤矿瓦斯深孔区域化抽采方法与装置 - Google Patents

一种煤矿瓦斯深孔区域化抽采方法与装置 Download PDF

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Publication number
WO2024078506A1
WO2024078506A1 PCT/CN2023/123822 CN2023123822W WO2024078506A1 WO 2024078506 A1 WO2024078506 A1 WO 2024078506A1 CN 2023123822 W CN2023123822 W CN 2023123822W WO 2024078506 A1 WO2024078506 A1 WO 2024078506A1
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WIPO (PCT)
Prior art keywords
drilling
fracturing
pressure
coal
hole
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PCT/CN2023/123822
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English (en)
French (fr)
Inventor
刘见中
孙海涛
王清峰
武文宾
胡运兵
王昊
赵旭生
闫保永
李良伟
雷毅
康厚清
王振
王然
陈泽平
孙朋
孙东玲
李日富
王国震
宁二强
祝琨
刘延保
姚壮壮
李彦明
潘雪松
段天柱
刘洋
胡万利
崔少北
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中国煤炭科工集团有限公司
中煤科工集团重庆研究院有限公司
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Publication of WO2024078506A1 publication Critical patent/WO2024078506A1/zh

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Classifications

    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B7/00Special methods or apparatus for drilling
    • E21B7/04Directional drilling
    • E21B7/046Directional drilling horizontal drilling
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B4/00Drives for drilling, used in the borehole
    • E21B4/02Fluid rotary type drives
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/006Production of coal-bed methane
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/25Methods for stimulating production
    • E21B43/26Methods for stimulating production by forming crevices or fractures
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B44/00Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions
    • E21B44/005Below-ground automatic control systems
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B47/00Survey of boreholes or wells
    • E21B47/02Determining slope or direction
    • E21B47/022Determining slope or direction of the borehole, e.g. using geomagnetism
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B47/00Survey of boreholes or wells
    • E21B47/12Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
    • E21B47/13Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling by electromagnetic energy, e.g. radio frequency
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B49/00Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21FSAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
    • E21F7/00Methods or devices for drawing- off gases with or without subsequent use of the gas for any purpose
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88Radar or analogous systems specially adapted for specific applications
    • G01S13/885Radar or analogous systems specially adapted for specific applications for ground probing
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01VGEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/12Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with electromagnetic waves

Definitions

  • the present invention relates to the field of underground coal mine gas extraction, and in particular to a method and device for deep hole regional extraction of coal mine gas.
  • the regional outburst prevention measures for pre-extraction of coal seam gas based on through-layer drilling can achieve regional pre-extraction of the entire section and start mining work after meeting the required indicators.
  • the biggest problem of this method is the large amount of engineering, long construction period and high cost.
  • Some coal mines need to arrange three to four rock tunnels to make the through-layer drilling cover the entire section of the coal seam.
  • the excavation speed of the rock tunnel is lagging, the drilling construction period and pre-extraction time are long, and the overall cost is high.
  • the existing downhole measurement device is 5 to 8 meters away from the drill bit, and the trajectory parameters are mainly static measurements, which leads to a lag in drilling trajectory measurement and control.
  • the operation of existing directional drilling rigs and the adjustment of drilling trajectories rely heavily on manual experience. The operators have large differences in experience levels, resulting in large errors in drilling trajectory adjustment.
  • the main purpose of the present invention is to solve the problems that it is currently impossible to guide drilling rig construction through geological detection while drilling, the existing directional drilling rig operation and drilling trajectory adjustment are heavily dependent on manual experience, there is no system for parameter design, and hydraulic fracturing is not carried out while drilling, so as to achieve the measurement of geological information of directional long boreholes while drilling, autonomous adjustment of drilling process parameters based on geological information detected while drilling, and hydraulic fracturing while drilling, so as to form a set of regionalized deep hole extraction equipment and method for coal mines with a simple system, simple operation and easy implementation, covering the entire mining area.
  • the coal mine gas deep hole regional extraction device of the embodiment of the present disclosure includes a high-pressure and large-flow centralized fluid supply device, a drilling radar geological detection device, a deep hole adaptive directional drilling device, an electromagnetic transmission high-pressure sealed pipe string, and an open hole drilling and segmented fracturing tool string;
  • the high-pressure and large-flow centralized fluid supply device is provided with a dual-pump structure, the outlet of the dual-pump structure is connected to the drilling and fracturing dual-mode fluid supply switching structure, and the high-pressure and large-flow centralized fluid supply device is connected to the electromagnetic transmission high-pressure sealed pipe string;
  • the electromagnetic transmission high-pressure sealed pipe string provides fracturing fluid for the open hole drilling and segmented fracturing tool string, and provides drilling fluid for the screw motor of the deep hole adaptive directional drilling device;
  • the drilling radar geological detection device is respectively connected to the open hole drilling and segmented fracturing tool string and the screw motor of the deep hole adaptive directional drilling device, and transmits signals through
  • the high-pressure and high-flow centralized fluid supply device is connected in sequence by a water tank, a dual-pump structure, a drilling and fracturing dual-mode fluid supply switching structure, a high-pressure hose, an orifice device, and a remote controller.
  • the dual pump structure is provided with a high-pressure small-flow pump group and a low-pressure large-flow pump group.
  • the high-pressure small-flow pump group and the low-pressure large-flow pump group are connected together on the same chassis and are connected together to a water tank and a remote controller.
  • a one-way valve inside the orifice device, one end of the one-way valve is threadedly connected to the electromagnetic transmission high-pressure sealing pipe column, and the other end of the one-way valve is connected to the high-pressure hose; a rotating water supply structure is provided at the end of the one-way valve connected to the high-pressure hose, and the one-way valve controls the fluid to pass only from one side of the high-pressure hose to one side of the electromagnetic transmission high-pressure sealing pipe column, and a pressure gauge and a pressure relief valve are also provided on one side of the electromagnetic transmission high-pressure sealing pipe column; when the high-pressure and large-flow centralized fluid supply device is used for fracturing, fracturing fluid is added to the water tank, and when the high-pressure and large-flow centralized fluid supply device is used for drilling, drilling fluid is added to the water tank.
  • the deep hole adaptive directional drilling device includes a drill bit, a near-drill-bit while-drilling measurement device, a screw motor, and an adaptive directional drilling rig host.
  • a near-bit measurement while drilling device is used to measure drilling trajectory parameters, and at the same time receive geological data information detected by a while drilling radar geological detection device, and transmit the data information to the adaptive directional drilling rig host through electromagnetic transmission high-pressure sealed pipe string. After data analysis and processing, the thrust and rotation speed are adaptively adjusted.
  • the drill bit, the near-drill bit measurement while drilling device, and the screw motor are connected in sequence; the screw motor is connected to the drilling radar geological detection device; the adaptive directional drilling rig main unit is connected to the electromagnetic transmission high-pressure sealing pipe column, and is connected to the high-pressure and large-flow centralized fluid supply device through a high-pressure hose.
  • the adaptive directional drilling rig main unit includes an anchoring cylinder group, an adaptive feeding device, a motor assembly, a fuel tank assembly, an adaptive power head, an explosion-proof computer, and a tracked vehicle platform; the anchoring cylinder group, the adaptive feeding device, the motor assembly, the fuel tank assembly, and the explosion-proof computer are all integrated on the tracked vehicle platform; the adaptive power head is located on the adaptive feeding device, providing rotational power for directional drilling and accurately adjusting the facing angle of the screw motor tool; the adaptive feeding device provides the propulsion force required for drilling.
  • the electromagnetic transmission high-pressure sealing column is a center tube-free structure, and uses electromagnetic induction to transmit signals.
  • the pressure-bearing capacity of the sealing structure is greater than the maximum pressure of the high-pressure and large-flow centralized liquid supply device, and does not affect signal transmission.
  • the electromagnetic transmission high-pressure sealed pipe string transmits drilling fluid to the screw motor during the drilling process, transmits fracturing fluid to the open hole downhole segmented fracturing tool string during the fracturing process, transmits drilling rig command signals during the drilling and fracturing processes and feeds back detection result information of the downhole radar geological detection device and drill bit status information.
  • the open hole drilling staged fracturing tool string includes an upper conversion structure, an upper packer, an upper stabilizer, a dual-mode pressure differential sliding sleeve and screen integrated short section, a lower stabilizer, a lower packer, and a lower conversion structure, wherein the upper conversion structure is connected to the drilling radar geological detection device, and the lower conversion structure is connected to the electromagnetic transmission high-pressure sealing pipe column; the upper conversion structure, the upper packer, the upper stabilizer, the dual-mode pressure differential sliding sleeve and screen integrated short section, the lower stabilizer, the lower packer, and the lower conversion structure are all provided with an electromagnetic transmission structure; the dual-mode pressure differential sliding sleeve and screen integrated short section includes two parts: a dual-mode pressure differential sliding sleeve and a screen, wherein the dual-mode pressure differential sliding sleeve is provided with a drilling fracturing dual-mode structure, and the screen is used for high-pressure water discharge.
  • the dual-mode differential pressure sleeve automatically switches between the drilling mode and the fracturing mode by adjusting the fluid supply pressure of the high-pressure and high-flow centralized fluid supply device.
  • the fluid supply pressure is below Pd , it is the drilling mode, and when the fluid supply pressure is greater than Pd , it is the fracturing mode, where Pd is adjustable between 10 and 20 MPa.
  • high-pressure water does not enter the upper packer, the lower packer and the screen, avoiding expansion of the upper packer and the lower packer and water discharge from the screen, and high-pressure water only enters the screw motor and provides power; in fracturing mode, high-pressure water does not enter the screw motor, the upper packer and the lower packer expand to seal the hole, and water discharges from the screen to perform staged internal fracturing.
  • the dual-mode differential pressure sleeve closes the upper packer and the lower packer in the fracturing mode, and the upper packer and the lower packer are depressurized and contracted.
  • the radar geological detection device while drilling includes a transmitting conformal antenna array, a transmitter control circuit, a receiver control circuit, a radar signal processor, a MEMS acceleration sensor, and a receiving conformal antenna array.
  • the radar signal processor processes the signal as follows: after transmitting a conformal antenna array to spirally scan the entire surrounding space, an intermittent radar reflection interface is formed, and the coal-rock interface at the top and bottom of the mining face is extracted in three-dimensional space to provide a stratified boundary for spatial division; the radar wave propagates in the coal seam, and the amplitude will attenuate with the increase of the propagation distance, and the phase will also shift accordingly.
  • the radar wave will be deflected and reflected; through the amplitude intensity and phase shift of the reflected wave, the tomography theory is used to invert the coal seam properties on the radar wave path to characterize the change information of the coal seam.
  • tetrahedral partitioning units are used to partition the three-dimensional space, thereby discretizing the entire three-dimensional space; regional encryption is performed for small-scale aperture constraints near the borehole; and the partitioning size is increased in the detection edge area.
  • the deep hole regional extraction method of coal mine gas in the embodiment of the present disclosure uses the deep hole regional extraction device of coal mine gas as described in any of the above embodiments, including the following steps:
  • Step 1 obtaining the geological environment, stress state and physical and mechanical parameters of the coal-rock layer, the parameters of the coal-rock layer include the coal-rock solidity coefficient f 1 , the roof solidity coefficient f 2 , the section strike length L, the section dip length N, the coal-rock thickness h, the coal-rock tensile strength ⁇ t , the coal-rock burial depth H, the coal-rock original horizontal maximum principal stress ⁇ H , the coal-rock original horizontal minimum principal stress ⁇ h , the pore pressure P 0 , the relative dielectric constant ⁇ r of the underground medium, and the water absorption coefficient ⁇ 2 of the roof and floor rock layers;
  • Step 2 designing the extraction drilling type and corresponding drilling parameters according to the acquired coal rock layer parameters and design formula
  • Step 3 using a deep hole adaptive directional drilling device, according to the extraction drilling parameters set in step 2, based on the geological information detected in real time and continuously by the drilling radar geological detection device during the drilling process, the propulsion force and rotation speed of the deep hole adaptive directional drilling device are adaptively adjusted to perform top plate parallel directional long drilling construction;
  • Step 4 according to the parameters of the target coal rock layer for fracturing, calculate the fracture pressure Pk of the coal layer, the pump pressure Pw of the fracturing pump and the amount of fracturing water Vwater ;
  • Step 5 calculating the length W of the fracturing segment of the top plate parallel directional long drilling and the distance U between the fracturing segments;
  • Step 6 performing hydraulic fracturing operation using the parameters obtained in steps 4 and 5 as design parameters;
  • Step 7 drain and seal the hole after fracturing, and connect the extraction device for extraction.
  • the extraction drilling type design method in step 2 is as follows:
  • the extraction drilling types are divided into two types: long directional drilling parallel to the roof and long directional drilling parallel to the roof + branch holes. Assuming that the ratio of the roof solidity coefficient f2 to the coal seam solidity coefficient f1 is D, D is calculated as follows:
  • the drilling parameter design method corresponding to the extraction drilling type in step 2 is as follows:
  • the drill bit When constructing branch holes, the drill bit passes through the coal seam and enters the bottom plate to a depth of x, where x is 5 to 10 m.
  • the drilling radar geological detection device in step 3 performs real-time and continuous detection during the drilling process.
  • the specific process is: during detection, the receiver control circuit synchronizes the instructions of the transmitter control circuit, and senses the posture of the drilling radar geological detection device in real time through the MEMS acceleration sensor, and starts one or more groups of corresponding transmitting conformal antenna arrays and receiving conformal antenna arrays according to its own posture to perform detection data collection and data analysis, and invert the geological information around the directional detection borehole; the drilling radar geological detection device transmits the coal-rock interface information to the deep hole adaptive directional drilling rig device through the electromagnetic transmission high-pressure sealed pipe string, and adjusts the screw motor azimuth and inclination in real time according to the coal-rock interface information during the drilling process to ensure the designed layer position of the drilling hole.
  • the calculation formula for the depth H of the target body at the coal-rock interface detected by the while-drilling radar geological detection device is as follows:
  • c is the speed of light
  • ⁇ r is the relative dielectric constant of the underground medium
  • the calculation formula of the sensing direction of the drilling radar geological detection device itself is as follows:
  • is the angle between the main detection direction of the while drilling radar geological detection device and the normal direction of the coal-rock interface;
  • g y is the initial horizontal radial direction sensor axis acceleration measurement value of the while drilling radar geological detection device;
  • g z is the initial vertical direction sensor axis acceleration measurement value of the while drilling radar geological detection device.
  • ⁇ h is the original horizontal minimum principal stress of the coal seam
  • ⁇ H is the original horizontal maximum principal stress of the coal seam
  • ⁇ t is the tensile strength of the coal rock
  • P 0 is the pore pressure
  • PH is the pressure of the liquid column in the fracturing pipeline
  • PH ⁇ gHc
  • is the density of the fracturing fluid
  • g is the acceleration of gravity
  • Hc is the height difference of the electromagnetic transmission high-pressure sealing pipe column, which is the elevation of the final hole minus the elevation of the opening
  • Pr is the friction resistance of the fracturing fluid along the way
  • Pr aLg ⁇ 1
  • Lg is the length of the pipeline
  • ⁇ 1 is the friction coefficient
  • a 1MPa/km
  • the fracturing water volume Vwater is estimated.
  • Vwater 0.02Vbody ⁇ 2
  • step 5 the length W of the fracturing segment parallel to the top plate and the distance U between the fracturing segments are calculated as follows:
  • f1 is the solidity coefficient of the coal seam
  • f2 is the solidity coefficient of the roof
  • M is the distance between the directional long borehole and the coal seam
  • h is the thickness of the coal seam
  • 1m 3/2 .
  • step 6 performs hydraulic fracturing operations according to design parameters.
  • the specific steps are as follows:
  • the high-pressure and large-flow centralized fluid supply device is started and controlled according to the staged hydraulic fracturing parameter design to start fracturing, and the fracturing pressure is adjusted to be higher than the pump pressure Pw of the fracturing pump.
  • the fracturing water volume Vwater is completed, the first stage fracturing at the bottom of the hole is stopped, and the electromagnetic transmission high-pressure sealing string is dragged to drive the open hole while drilling staged fracturing tool string, so that the distance between the upper packer and the lower packer position of the first stage fracturing is the fracturing stage spacing U, and the second stage fracturing is carried out.
  • the above steps are repeated until all staged fracturing are completed.
  • step 6 performs hydraulic fracturing operations according to design parameters.
  • the specific steps are as follows:
  • the dual-mode pressure difference sliding sleeve screen integrated short section to control the spacing between the upper packer and the lower packer, so that the spacing is greater than the length of the borehole in the coal seam section.
  • the first branch hole is constructed at the bottom of the hole.
  • the positions of the upper packer and the lower packer are adjusted so that the two are located at the bottom and roof of the coal seam respectively; according to the staged hydraulic fracturing parameter design, start and control the high-pressure and large-flow centralized fluid supply device to start fracturing, adjust the fracturing pressure to be higher than the fracturing pump pressure Pw , and stop the fracturing of the first branch hole when the fracturing water volume Vwater is completed; drag the electromagnetic transmission high-pressure sealing pipe string to make the drill bit at the opening point of the second branch hole, the distance between the second opening point and the first opening point is O, start drilling the second branch hole and perform drilling fracturing, and repeat the above steps until all branch holes are fracturing.
  • a temporary negative pressure device is installed at the borehole mouth to extract positive pressure gas generated during drainage to prevent excessive gas inside the drilling site.
  • cement mortar is used to seal the hole.
  • VP is within the range of 0.2 to 0.5 m 3 /h. After sealing, the hole is connected to an extraction device for extraction.
  • the present invention discloses a method and device for regionalized deep-hole extraction of coal mine gas, which has a simple structure and is easy to operate.
  • a high-pressure, large-flow centralized fluid supply device and an electromagnetic transmission high-pressure sealed pipe column are used in common during drilling and fracturing.
  • a drilling radar geological detection device does not need to be drilled out before detection. The detection result directly guides the drilling process.
  • the drilling process operates autonomously.
  • the open-hole staged fracturing tool string can be operated while drilling, so that large-area advanced and efficient gas extraction without tunneling can be realized in coal mines with soft coal seams as the main components.
  • FIG1 is a schematic diagram of the deep hole regional extraction process of coal mine gas disclosed in the present invention.
  • FIG2 is a three-dimensional schematic diagram of the arrangement of regionalized deep-hole extraction drilling holes for coal mine gas disclosed in the present invention
  • FIG3 is a general schematic diagram of the deep hole regionalized extraction device for coal mine gas disclosed in the present invention.
  • FIG4 is a schematic diagram of a radar geological detection device while drilling disclosed in the present invention.
  • FIG5 is a schematic diagram of a mainframe of an adaptive directional drilling rig disclosed in the present invention.
  • FIG6 is a schematic diagram of an open hole staged fracturing while drilling tool string according to the present invention.
  • Figures 3-6 are schematic diagrams of the overall and components of the deep hole regional extraction device for coal mine gas disclosed in the present invention.
  • the deep hole regional extraction device for coal mine gas includes a high-pressure and high-flow centralized liquid supply device, a radar geological detection device while drilling 4, a deep hole adaptive directional drilling device, an electromagnetic transmission high-pressure sealing pipe string 5, and a naked hole while drilling segmented fracturing tool string.
  • the high-pressure, high-flow centralized liquid supply device is connected in sequence by a water tank 701, a dual-pump structure 702, a drilling and fracturing dual-mode liquid supply switching structure 703, a high-pressure hose 704, an orifice device 705, and a remote controller 706.
  • the dual-pump structure 702 is provided with a high-pressure, low-flow pump group and a low-pressure, high-flow pump group, which are connected together on the same chassis and connected together to the water tank 701 and the remote controller 706.
  • the dual-pump structure 702 is provided with a high-pressure, low-flow pump group and a low-pressure, high-flow pump group, which are connected together on the same chassis and connected together to the water tank 701 and the remote controller 706.
  • a rotating water supply structure is provided at the end of the one-way valve connected to the high-pressure hose 704, and the one-way valve controls the fluid to pass only from one side of the high-pressure hose 704 to the other side of the electromagnetic transmission high-pressure sealed pipe column 5.
  • a pressure gauge and a pressure relief valve are also provided on one side of the electromagnetic transmission high-pressure sealed pipe column 5; when the high-pressure and large-flow centralized liquid supply device is used for fracturing, fracturing fluid is added to the water tank 701, and when the high-pressure and large-flow centralized liquid supply device is used for drilling, drilling fluid is added to the water tank 701.
  • the deep hole adaptive directional drilling device includes a drill bit 1, a near-drill bit while drilling measurement device 2, a screw motor 3, and an adaptive directional drilling machine mainframe 6.
  • the drill bit 1, the near-drill bit while drilling measurement device 2, and the screw motor 3 are connected in sequence; the screw motor 3 is connected to the while drilling radar geological detection device 4; the adaptive directional drilling machine mainframe 6 is connected to the electromagnetic transmission high-pressure sealed pipe column 5, and is connected to the high-pressure and high-flow centralized fluid supply device through a high-pressure hose 704.
  • the near-drill bit while drilling measurement device 2 is used to measure the drilling trajectory parameters, and at the same time receives the geological data information detected by the while drilling radar geological detection device 4, and transmits the data information to the adaptive directional drilling machine mainframe 6 through the electromagnetic transmission high-pressure sealed pipe column 5. After data analysis and processing, the propulsion force and rotation speed are adaptively adjusted.
  • the electromagnetic transmission high-pressure sealed pipe string 5 is a structure without a central tube, and adopts electromagnetic induction to transmit signals.
  • the pressure bearing capacity of the sealing structure is greater than the maximum pressure of the high-pressure and large-flow centralized fluid supply device, and does not affect signal transmission.
  • the electromagnetic transmission high-pressure sealed pipe string 5 transmits drilling fluid for the screw motor 3 during drilling, transmits fracturing fluid for the open-hole segmented fracturing tool string during fracturing, transmits drilling rig command signals, and feeds back the detection result information of the drilling radar geological detection device 4 and the status information of the drill bit 1 during drilling and fracturing.
  • the high-pressure and large-flow centralized fluid supply device is connected to the drilling and fracturing dual-mode fluid supply switching structure 703 at the outlet of the dual pump structure 702, and is connected to the electromagnetic transmission high-pressure sealed pipe string 5 through the orifice device 705.
  • the drilling radar geological detection device is respectively connected to the screw motor 3 of the open-hole segmented fracturing tool string and the deep hole adaptive directional drilling rig device, and transmits signals through the electromagnetic transmission high-pressure sealed pipe string 5.
  • the radar geological detection device 4 for drilling includes a transmitting conformal antenna array 401, a transmitter control circuit 402, a receiver control circuit 403, a radar signal processor 404, a MEMS acceleration sensor 405, and a receiving conformal antenna array 406.
  • the signal processing process of the radar signal processor 404 is as follows: after the transmitting conformal antenna array 401 spirally scans the entire surrounding space, a discontinuous radar reflection interface is formed, and the top and bottom coal-rock interfaces of the mining working face are extracted in the three-dimensional space to provide a layered boundary for space segmentation; when the radar wave propagates in the coal seam, the amplitude will attenuate with the increase of the propagation distance, and the phase will also shift accordingly.
  • the radar wave will be deflected and reflected; through the amplitude intensity and phase shift of the reflected wave, the tomography theory is used to invert the coal seam properties on the radar wave path to characterize the change information of the coal seam.
  • the segmentation of the three-dimensional space specifically adopts a tetrahedral segmentation unit to discretize the entire three-dimensional space; for the small-scale aperture constraints near the borehole, regional encryption is performed; in the detection edge area, the segmentation size is increased.
  • the main unit 6 of the adaptive directional drilling rig provides propulsion and rotational power for directional drilling.
  • the main unit 6 of the adaptive directional drilling rig includes an anchoring cylinder group 601, an adaptive feeding device 602, a motor assembly 603, a fuel tank assembly 604, an adaptive power head 605, an explosion-proof computer 606, and a crawler platform 607;
  • the anchoring cylinder group 601, the adaptive feeding device 602, the motor assembly 603, the fuel tank assembly 604, and the explosion-proof computer 606 are all integrated on the crawler platform 607;
  • the adaptive power head 605 is located on the adaptive feeding device 602, providing rotational power for directional drilling and accurately adjusting the tool face angle of the screw motor 3;
  • the adaptive feeding device 602 provides the propulsion required for drilling.
  • the open hole drilling staged fracturing tool string includes an upper conversion structure 801, an upper packer 802, an upper stabilizer 803, a dual-mode pressure differential sliding sleeve and screen integrated short section 804, a lower stabilizer 805, a lower packer 806, and a lower conversion structure 807.
  • the upper conversion structure 801 is connected to the drilling radar geological detection device 4, and the lower conversion structure 807 is connected to the electromagnetic transmission high-pressure sealing pipe column 5;
  • the upper conversion structure 801, the upper packer 802, the upper stabilizer 803, the dual-mode pressure differential sliding sleeve and screen integrated short section 804, the lower stabilizer 805, the lower packer 806, and the lower conversion structure 807 are all provided with an electromagnetic transmission structure;
  • the dual-mode pressure differential sliding sleeve and screen integrated short section 804 includes two parts, a dual-mode pressure differential sliding sleeve and a screen, wherein the dual-mode pressure differential sliding sleeve is provided with a drilling fracturing dual-mode structure, and the screen is used for high-pressure water discharge.
  • the dual-mode differential pressure sleeve automatically switches between the drilling mode and the fracturing mode by adjusting the fluid supply pressure of the high-pressure and high-flow centralized fluid supply device.
  • the drilling mode is when the fluid supply pressure is below P d
  • the fracturing mode is when the fluid supply pressure is greater than P d , wherein P d is adjustable between 10 and 20 MPa.
  • high-pressure water does not enter the upper packer 802, the lower packer 806, and the screen tube, so as to avoid the expansion of the upper packer 802 and the lower packer 806 and the water discharge of the screen tube.
  • the high-pressure water only enters the screw motor 3 and provides power.
  • the high-pressure water does not enter the screw motor 3, the upper packer 802 and the lower packer 806 expand and seal the hole, and the screen tube discharges water for staged internal fracturing.
  • the dual-mode differential pressure sleeve closes the upper packer 802 and the lower packer 806 in the fracturing mode, and the upper packer 802 and the lower packer 806 are depressurized and contracted.
  • the open hole staged fracturing while drilling tool string is also provided with a fracturing while drilling electromagnetic transmission communication structure, and data is transmitted through the electromagnetic transmission communication structure.
  • the deep hole regional extraction method of coal mine gas in Example 1 includes the following steps.
  • Step 2 Based on the coal and rock layer parameters obtained, design the extraction drilling type and corresponding drilling parameters according to the following method.
  • Drainage drilling type classification Drainage drilling types are divided into two types: roof parallel directional long drilling and roof parallel directional long drilling + branch holes.
  • the ratio of roof solidity coefficient to coal seam solidity coefficient is set to D, and D is a dimensionless parameter. The small value represents the possibility of the roof extending the cracks to the coal seam through hydraulic fracturing. Whether to design branch holes is determined based on the possibility. D is calculated as follows:
  • f1 is the solidity coefficient of the coal seam
  • f2 is the solidity coefficient of the roof
  • D ⁇ 2 a long directional borehole parallel to the roof + a branch hole are used.
  • D>2 is calculated, so the type of extraction drilling used is a long directional borehole parallel to the roof.
  • the receiver control circuit 403 synchronizes the transmitter control circuit 402 instructions, and senses the device posture in real time through the MEMS acceleration sensor 405, and starts one or more corresponding transmitting conformal antenna arrays 401 and receiving conformal antenna arrays 406 according to their own postures to collect detection data and analyze data, and invert the geological information around the directional detection borehole.
  • the drilling radar geological detection device 4 transmits the coal-rock interface information to the deep hole adaptive directional drilling device through the electromagnetic transmission high-pressure sealing pipe string 5, and adjusts the screw motor 3 azimuth and inclination in real time according to the coal-rock interface information during the drilling process to ensure the designed layer position of the drilling hole.
  • the target depth H of the coal-rock interface detected by the drilling radar is calculated as follows:
  • c is the speed of light and ⁇ r is the relative dielectric constant of the underground medium.
  • the calculation formula of the sensing direction of the drilling radar geological detection device 4 itself is as follows:
  • is the angle between the main detection direction of the drilling radar geological detection device 4 and the normal direction of the coal-rock interface;
  • g y is the initial horizontal radial direction sensor axis acceleration measurement value of the drilling radar geological detection device 4;
  • g z is the acceleration measurement value of the drilling radar geological detection device 4 Initial vertical sensing axis acceleration measurement.
  • Step 4 Calculate the fracture pressure P k , fracturing pump pressure P w , and fracturing water volume V water of the coal seam according to the geological environment, stress state, physical mechanics and other parameters of the target coal rock layer for fracturing, so as to provide data for subsequent staged fracturing operation while drilling.
  • the fracture pressure P k of coal seam is calculated according to the following formula.
  • P k 3 ⁇ h - ⁇ H + ⁇ t -P 0
  • ⁇ h is the original horizontal minimum principal stress of the coal seam
  • ⁇ H is the original horizontal maximum principal stress of the coal seam
  • ⁇ t is the tensile strength of coal rock
  • P 0 is the pore pressure.
  • the fracturing water volume Vwater is estimated.
  • Vwater 0.02Vbody ⁇ 2
  • Vbody is the volume of the coal seam within the designed fracturing influence range, and the volume of the coal seam estimated based on the drilling spacing segmentation parameters is about 2250m3 ;
  • Vwater 45m3 .
  • Step 5 calculate the length W of the fracturing segment and the distance U between the fracturing segments of the directional long borehole parallel to the roof.
  • the length W of the fracturing segment of the long directional drilling parallel to the roof and the distance U between the fracturing segments are calculated as follows:
  • f1 is the solidity coefficient of the coal seam
  • f2 is the solidity coefficient of the roof
  • M is the distance between the directional long borehole and the coal seam
  • h is the thickness of the coal seam
  • 1m 3/2 .
  • Step 6 Perform hydraulic fracturing operations according to the above design parameters.
  • Step 7 After fracturing, drain the water, seal the hole, and connect the extraction device for extraction.
  • a temporary negative pressure device at the hole mouth to extract the positive pressure gas during the drainage process to prevent the gas inside the drilling site from exceeding the limit.
  • V P is within the range of 0.2 to 0.5 m 3 /h.
  • the deep hole regionalized coal mine gas extraction method in Example 2 comprises the following steps:
  • Step 2 Based on the coal and rock layer parameters obtained, design the extraction drilling type and corresponding drilling parameters according to the following method.
  • Drainage drilling type classification Drainage drilling types are divided into two types: long directional drilling parallel to the roof and long directional drilling parallel to the roof + branch holes.
  • the ratio of the roof solidity coefficient to the coal seam solidity coefficient is set to D.
  • the D value is a dimensionless parameter.
  • the size of D represents the possibility of the roof extending the cracks to the coal seam through hydraulic fracturing. Whether to design a branch hole is determined based on the possibility. D is calculated as follows:
  • f1 is the solidity coefficient of the coal seam
  • f2 is the solidity coefficient of the roof
  • D is calculated to be 1.6.
  • D>2 a long directional borehole parallel to the roof is used
  • D ⁇ 2 a long directional borehole parallel to the roof + a branch hole is used.
  • the D value calculated in this embodiment is less than 2, so the type of extraction drilling used is a long directional borehole parallel to the roof + a branch hole.
  • the receiver control circuit 403 synchronizes the transmitter control circuit 402 instructions, and senses the device posture in real time through the MEMS acceleration sensor 405, and starts one or more corresponding transmitting conformal antenna arrays 401 and receiving conformal antenna arrays 406 according to their own postures to collect detection data and analyze data, and invert the geological information around the directional detection borehole.
  • the drilling radar geological detection device 4 transmits the coal-rock interface information to the deep hole adaptive directional drilling device through the electromagnetic transmission high-pressure sealing pipe string 5, and adjusts the screw motor 3 azimuth and inclination in real time according to the coal-rock interface information during the drilling process to ensure the designed layer position of the drilling hole.
  • the depth H of the target body at the coal-rock interface detected by the drilling radar geological detection device 4 is calculated as follows:
  • c is the speed of light and ⁇ r is the relative dielectric constant of the underground medium.
  • the calculation formula of the sensing direction of the drilling radar geological detection device 4 itself is as follows:
  • is the angle between the main detection direction of the while drilling radar geological detection device 4 and the normal direction of the coal-rock interface;
  • g y is the initial horizontal radial direction sensing axis acceleration measurement value of the while drilling radar geological detection device 4;
  • g z is the initial vertical direction sensing axis acceleration measurement value of the while drilling radar geological detection device 4.
  • Step 4 Calculate the fracture pressure P k , fracturing pump pressure P w , and fracturing water volume V water of the coal seam according to the geological environment, stress state, physical mechanics and other parameters of the target coal rock layer for fracturing, so as to provide data for subsequent staged fracturing operation while drilling.
  • ⁇ h is the original horizontal minimum principal stress of the coal seam
  • ⁇ H is the original horizontal maximum principal stress of the coal seam
  • ⁇ t is the tensile strength of coal rock
  • P 0 is the pore pressure.
  • the pump pressure of the fracturing pump Pw 22.5MPa.
  • the fracturing water volume Vwater is estimated.
  • Vwater 0.02Vbody ⁇ 2
  • V is the volume of the coal seam within the designed fracturing influence range.
  • ⁇ 2 is the water absorption coefficient of the top and bottom strata, and is determined by the solidity coefficient f2 of the top strata.
  • Vwater 39.06m3 .
  • Step 5 calculate the length W of the fracturing segment of the long directional borehole parallel to the top plate and the distance U between the fracturing segments.
  • the drilling type selected this time is the long directional borehole parallel to the top plate + branch hole, so this step does not need to be calculated.
  • Step 6 Perform hydraulic fracturing operations according to the above design parameters.
  • the electromagnetic transmission high-pressure sealing string 5 is dragged to make the drill bit at the opening point of the second branch hole.
  • the second branch hole is drilled and fracturing is performed while drilling. This is repeated until all branch holes are fractured.
  • Step 7 After fracturing, drain the water, seal the hole, and connect the extraction device for extraction.
  • a temporary negative pressure device at the hole mouth to extract the positive pressure gas during the drainage process to prevent the gas inside the drilling site from exceeding the limit.
  • V P is within the range of 0.2 to 0.5 m 3 /h.
  • first and second are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated.
  • a feature defined as “first” or “second” may explicitly or implicitly include at least one of the features.
  • “plurality” means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
  • the terms “installed”, “connected”, “connected”, “fixed” and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined.
  • installed installed”, “connected”, “connected”, “fixed” and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined.
  • the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.
  • a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium.
  • a first feature being “above”, “above” or “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature.
  • a first feature being “below”, “below” or “below” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. This means that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is smaller in level than the second feature.
  • the terms “one embodiment”, “some embodiments”, “examples”, “specific examples”, or “some examples” and the like mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure.
  • the schematic representations of the above terms do not necessarily refer to the same embodiment or example.
  • the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner.
  • those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

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Abstract

公开了一种煤矿瓦斯深孔区域化抽采装置,包括高压大流量集中供液装置、随钻雷达地质探测装置(4)、深孔自适应定向钻机装置、电磁传输高压密封管柱(5)、裸眼随钻分段压裂工具串;随钻雷达地质探测装置在钻进过程中实时连续探测地质构造与煤岩交界面;深孔自适应定向钻机装置基于探测结果自适应调节推进力、回转速度,以提高钻进效率,降低钻进过程卡钻和抱钻概率;能够有效指导大区域瓦斯治理尤其是松软煤层的抽采钻孔设计、随钻雷达地质探测、自适应钻进、主孔分段压裂和分支钻孔随钻压裂的实施,从而对以松软煤层为主的煤矿实现井下无巷化大区域瓦斯超前高效抽采;还公开了使用该装置的方法。

Description

一种煤矿瓦斯深孔区域化抽采方法与装置
相关申请的交叉引用
本申请基于申请号为202211253874.9、申请日为2022年10月13日的中国专利申请提出,并要求该中国专利申请的优先权,该中国专利申请的全部内容在此引入本申请作为参考。
技术领域
本公开涉及煤矿井下瓦斯抽采领域,具体涉及一种煤矿瓦斯深孔区域化抽采的方法与装置。
背景技术
以2009年《防治煤与瓦斯突出规定》发布为标志,“区域防突措施先行、局部防突措施补充”的防突工作原则被提出,我国正式进入了以区域防突为主的区域瓦斯治理第一阶段。第一阶段区域预抽要求的范围比较小,仍然存在周期性的循环交替问题。对于一个走向1000m长的区段而言,需要交替数十个循环才能完成工作面回采巷道的掘进,防突与掘进作业的矛盾对立没有从根本上得到解决,抽采的时间、质量难以可靠保证的问题仍然存在,甚至还很严重。以穿层钻孔为主的预抽煤层瓦斯区域防突措施,能够做到对整个区段进行区域预抽并达到要求指标后再开始采掘工作。但该方式的最大问题是工程量大、工期长、成本高。部分煤矿需布置三至四条岩巷才能使穿层钻孔覆盖整个区段煤层,岩巷掘进速度滞后、钻孔施工工期和预抽时间长,整体成本高。
2019年版《防治煤与瓦斯突出细则》(简称《防突细则》)首次将“定向长钻孔预抽煤巷条带煤层瓦斯”列为区域防突措施,控制范围有所提升,但抽、掘交替问题仍然存在,千米工作面要交替多次。这不仅影响综合掘进速度,关键是只要存在掘进等抽采的情况,就会有抽采效果难以保证的问题。在钻进及控制方面,当区域范围增大后,区域内煤层及顶底板赋存条件变化多端,对钻孔轨迹控制的要求更高,现有随钻测量装置远离钻头5~8m,且轨迹参数以静态测量为主,这导致钻孔轨迹测量和控制滞后。另外现有定向钻机操作和钻孔轨迹调整严重依赖人工经验,操作人员因经验水平差异大,造成钻孔轨迹调整误差大。
此外,很大部分未采用增渗措施的定向长钻孔存在“打得进,抽不出”问题,这种钻孔施工成本高效果低的原因主要是当前的水力压裂与钻孔施工作业不紧密,设备不通用,施工后未进行增渗作业,钻机撤场后更无法进行增渗作业,而目前最适合于定向长钻孔的增渗技术仍然是水力压裂,因此亟需一套结构简单操作便利的钻孔与水力压裂装置。
综上,针对当前的瓦斯治理技术无法避免抽、掘、采交替的问题或采用专用治理巷道工程量大的问题,亟需一种以整个采区为范围的煤矿井下深孔区域化抽采方法及装置对煤层瓦斯进行抽采。基于该方法及装置能实现随钻探测、自适应钻进,实现整个采区超前预抽,最终达到一个采区预抽达标后,再投入该区段的采掘目标,避免或尽可能减少在一个区段内的抽、掘、采交替。
发明内容
本公开的主要目的在于解决目前无法做到随钻地质探测指导钻机施工、现有定向钻机操作和钻孔轨迹调整严重依赖人工经验、参数设计无体系、水力压裂不随钻等问题,实现定向长钻孔地质信息随钻测量、基于随钻探测地质信息的钻进工艺参数自主调节、水力压裂随钻化,形成一套***简单操作简实施简便的以整个采区为范围的煤矿井下深孔区域化抽采装置及方法。
为实现上述目的,本公开的技术方案是:
本公开实施例的煤矿瓦斯深孔区域化抽采装置包括高压大流量集中供液装置、随钻雷达地质探测装置、深孔自适应定向钻机装置、电磁传输高压密封管柱、裸眼随钻分段压裂工具串;高压大流量集中供液装置设置有双泵结构,双泵结构出口连接钻进压裂双模式供液切换结构,高压大流量集中供液装置连接电磁传输高压密封管柱;电磁传输高压密封管柱为裸眼随钻分段压裂工具串提供压裂液,为深孔自适应定向钻机装置的螺杆马达提供钻进液;随钻雷达地质探测装置分别与裸眼随钻分段压裂工具串和深孔自适应定向钻机装置的螺杆马达连接,并通过电磁传输高压密封管柱传输信号;裸眼随钻分段压裂工具串设置有随钻压裂电磁传输通讯结构和双模式压差滑套,通过电磁传输通讯结构传输数据,通过双模式压差滑套切换钻进模式和压裂模式。
在一些实施例中,高压大流量集中供液装置由水箱、双泵结构、钻进压裂双模式供液切换结构、高压胶管、孔口装置、远程控制器依次连接。
在一些实施例中,双泵结构设置有高压小流量泵组、低压大流量泵组,高压小流量泵组和低压大流量泵组共同连接在同一底盘上,共同连接水箱及远程控制器。
在一些实施例中,孔口装置内部有单向阀,单向阀的一端与电磁传输高压密封管柱螺纹连接,单向阀的另一端与高压胶管连接;单向阀与高压胶管连接的一端设置有旋转输水结构,单向阀控制流体仅能由高压胶管一侧至电磁传输高压密封管柱一侧通过,电磁传输高压密封管柱一侧还设置有压力表和卸压阀;当高压大流量集中供液装置用于压裂时,在水箱内添加压裂液,当高压大流量集中供液装置用于钻进时,在水箱内添加钻进液。
在一些实施例中,深孔自适应定向钻机装置包括钻头、近钻头随钻测量装置、螺杆马达、自适应定向钻机主机。
在一些实施例中,近钻头随钻测量装置用于测量钻孔轨迹参数,同时接收来自随钻雷达地质探测装置探测的地质数据信息,通过电磁传输高压密封管柱将数据信息传输至自适应定向钻机主机上,经过数据分析及处理后,自适应调节推进力和回转速度。
在一些实施例中,钻头、近钻头随钻测量装置、螺杆马达依次连接;螺杆马达与随钻雷达地质探测装置连接;自适应定向钻机主机与电磁传输高压密封管柱连接,并通过高压胶管与高压大流量集中供液装置连接。
在一些实施例中,自适应定向钻机主机包括锚固油缸组、自适应给进装置、电动机组件、油箱组件、自适应动力头、防爆电脑、履带车平台;锚固油缸组、自适应给进装置、电动机组件、油箱组件、防爆电脑均集成在履带车平台上;自适应动力头位于自适应给进装置上,为定向钻孔提供回转动力并精确调整螺杆马达工具面向角角度;自适应给进装置提供钻孔所需的推进力。
在一些实施例中,电磁传输高压密封管柱为无中心管结构,采用电磁感应方式进行信号传输,密封结构承压能力大于高压大流量集中供液装置最高压力,且不影响信号传输。
在一些实施例中,电磁传输高压密封管柱在钻进过程中为螺杆马达传输钻进液,在压裂过程中为裸眼随钻分段压裂工具串传输压裂液,在钻进和压裂过程中传输钻机指令信号并反馈随钻雷达地质探测装置探测结果信息和钻头的状态信息。
在一些实施例中,裸眼随钻分段压裂工具串包括上转换结构、上封隔器、上扶正器、双模式压差滑套筛管一体化短节、下扶正器、下封隔器、下转换结构,其中上转换结构与随钻雷达地质探测装置连接,下转换结构与电磁传输高压密封管柱连接;上转换结构、上封隔器、上扶正器、双模式压差滑套筛管一体化短节、下扶正器、下封隔器、下转换结构均设置有电磁传输结构;双模式压差滑套筛管一体化短节包含双模式压差滑套和筛管两部分,其中双模式压差滑套设置有钻进压裂双模式结构,筛管用于高压水出水。
在一些实施例中,双模式压差滑套通过调节高压大流量集中供液装置的供液压力自动切换钻进模式和压裂模式,供液压力在Pd以下时为钻进模式,供液压力大于Pd时为压裂模式,其中Pd在10~20MPa之间可调。
在一些实施例中,在钻进模式时高压水不进入上封隔器、下封隔器和筛管,避免上封隔器和下封隔器膨胀以及筛管出水,高压水只进入螺杆马达并提供动力;在压裂模式时,高压水不进入螺杆马达,上封隔器、下封隔器膨胀封孔,筛管出水进行分段内压裂,压力降至Pd以下时双模式压差滑套关闭压裂模式上封隔器、下封隔器,上封隔器和下封隔器卸压收缩。
在一些实施例中,随钻雷达地质探测装置包括发射共形天线阵列、发射机控制电路、接收机控制电路、雷达信号处理器、MEMS加速度传感器、接收共形天线阵列。
在一些实施例中,雷达信号处理器对信号的处理过程为:发射共形天线阵列螺旋式扫描周边全部空间后,形成间断式的雷达反射界面,在三维空间中提取采掘工作面顶底煤岩分界面,为空间剖分提供分层边界;雷达波在煤层中传播,振幅会随着传播距离的增加而衰减,相位也随之偏移,在地层界面,雷达波会出现偏转和反射;通过反射波的振幅强度与相位偏移,利用层析成像理论,反演雷达波路径上的煤层属性,表征煤层的变化信息。
在一些实施例中,对三维空间的剖分采用四面体剖分单元,从而离散整个三维空间;对于钻孔附近小尺度的孔径约束,进行区域化加密;在探测边缘区域,增大剖分尺寸。
本公开实施例的煤矿瓦斯深孔区域化抽采方法,应用如上述任一实施例中所述的煤矿瓦斯深孔区域化抽采装置,包括以下步骤:
步骤1,获取煤岩层的地质环境、应力状态和物理力学参数,煤岩层的参数包括煤层坚固性系数f1、顶板坚固性系数f2、区段走向长度L、区段倾向长度N、煤层厚度h、煤岩抗拉强度σt、煤层埋深H、煤层原始水平最大主应力σH、煤层原始水平最小主应力σh、孔隙压力P0、地下介质的相对介电常数εr、顶底板岩层吸水系数λ2
步骤2,根据获取的煤岩层的参数和设计公式设计抽采钻孔类型及对应钻孔参数;
步骤3,采用深孔自适应定向钻机装置,根据步骤2中设置的抽采钻孔参数,基于随钻雷达地质探测装置在钻进过程中实时连续探测的地质信息,自适应调节深孔自适应定向钻机装置的推进力和回转速度,进行顶板平行定向长钻孔施工;
步骤4,根据压裂目标煤岩层的参数,计算煤层的破裂压力Pk、压裂泵泵压Pw以及压裂水量V
步骤5,计算顶板平行定向长钻孔压裂分段长度W和压裂段间距U;
步骤6,以步骤4和步骤5得到的参数作为设计参数进行水力压裂作业;
步骤7,压裂后进行排水、封孔,连接抽采装置进行抽采。
在一些实施例中,其中步骤2的抽采钻孔类型设计方法如下:
抽采钻孔类型分为顶板平行定向长钻孔和顶板平行定向长钻孔+分支孔两种类型,设顶板坚固性系数f2与煤层坚固性系数f1比值为D,D按下式计算:
其中D>2时采用顶板平行定向长钻孔,D≤2时,采用顶板平行定向长钻孔+分支孔。
在一些实施例中,其中步骤2的抽采钻孔类型对应的钻孔参数设计方法如下:
分支孔施工时钻头穿过煤层并进入底板深度为x,x取值为5~10m;
顶板平行定向长钻孔参数:顶板平行定向长钻孔层位在煤层上方M处,钻孔长度为K,钻孔间距为P,钻孔个数为B,M、K、P、B值分别按下式计算,其中ε=1m2
M=2h-f2
K=L+30

顶板平行定向长钻孔+分支孔参数:顶板平行定向长钻孔层位在煤层上方M处,钻孔长度为K,钻孔间距为P,钻孔主孔个数为B,分支钻孔间距O=P,分支孔个数为q,q按下式计算:
在一些实施例中,其中步骤3中的随钻雷达地质探测装置在钻进过程中实时连续探测,具体过程为:探测时,接收机控制电路同步发射机控制电路的指令,并通过MEMS加速度传感器实时感知随钻雷达地质探测装置姿态,根据自身姿态启动一组或多组相应的发射共形天线阵列和接收共形天线阵列进行探测数据采集工作与数据分析,反演出定向探测钻孔周围地质信息;随钻雷达地质探测装置将煤岩交界面信息通过电磁传输高压密封管柱传输给深孔自适应定向钻机装置,在钻进过程中根据煤岩交界面信息实时调整螺杆马达方位与倾角,保证钻孔设计层位。
在一些实施例中,其中随钻雷达地质探测装置探测煤岩交界面目标体深度H计算公式如下:
上式中,v为电磁波在介质中的波速;t为探测仪器测量的电磁波走时;x为发射共形天线阵列与接收共形天线阵列之间的距离;v值可用宽角法直接测量或根据近似计算公式计算:
上式中,c为光速,εr为地下介质的相对介电常数;
随钻雷达地质探测装置自身感知方向计算公式如下:
上式中,θ为随钻雷达地质探测装置探测主方向与煤岩交界面法线方向角度;gy为随钻雷达地质探测装置初始水平径向方向传感轴加速度测量值;gz为随钻雷达地质探测装置初始竖直方向传感轴加速度测量值。
在一些实施例中,其中步骤4中煤层的破裂压力Pk,计算公式如下:
Pk=3σhHt-P0
上式中:σh为煤层原始水平最小主应力,σH为煤层原始水平最大主应力,σt为煤岩抗拉强度,P0为孔隙压力;
计算需要的压裂泵泵压Pw,Pw计算公式如下:
Pw=Pk+PH+Pr
上式中:PH为压裂管路液柱压力,PH=ρgHc,ρ为压裂液密度;g为重力加速度,Hc为电磁传输高压密封管柱高差,为钻孔终孔标高减去开口标高;Pr为压裂液沿程摩阻,Pr=aLgλ1,Lg为管路长度,λ1为摩阻系数,a=1MPa/km;
依据压裂目标煤岩层设计的钻孔间距参数,考虑压力水漏失,估算压裂水量V
V计算公式如下
V=0.02Vλ2
上式中V为设计的压裂影响范围煤层体积;λ2为顶底板岩层吸水系数,根据顶板坚固性系数f2取值:f2>2时,λ2取值为1,f2为其它数值时,λ2=1.7-0.35f2
在一些实施例中,其中步骤5中顶板平行定向长钻孔压裂分段长度W和压裂段间距U按下式计算:

上式中,f1为煤层坚固性系数,f2为顶板坚固性系数,M为定向长钻孔距煤层距离,h为煤层厚度,β=1m3/2
在一些实施例中,其中步骤6根据设计参数进行水力压裂作业,对于顶板平行定向长钻孔随钻压裂作业,具体步骤如下:
利用煤矿瓦斯深孔区域化抽采装置进行钻孔施工前,调节好双模式压差滑套筛管一体化短节来控制上封隔器与下封隔器之间的间距至顶板平行定向长钻孔压裂分段长度W;
顶板平行定向长钻孔施工完成后,根据分段水力压裂参数设计启动并控制高压大流量集中供液装置开始压裂,调节压裂压力至高于压裂泵泵压Pw,完成压裂水量V时停止孔底第1段压裂,拖动电磁传输高压密封管柱带动裸眼随钻分段压裂工具串,使上封隔器距第1段压裂的下封隔器位置的距离为压裂段间距U进行第2段压裂,重复上述步骤直至所有分段压裂完成。
在一些实施例中,其中步骤6根据设计参数进行水力压裂作业,对于顶板平行定向长钻孔+分支孔随钻压裂作业,具体步骤如下:
利用煤矿瓦斯深孔区域化抽采装置进行钻孔施工前,调节好双模式压差滑套筛管一体化短节来控制上封隔器与下封隔器之间的间距,使该间距大于钻孔在煤层段内的长度,顶板平行定向长钻孔施工完后,在孔底开始施工第1个分支孔,施工完成后调整上封隔器与下封隔器的位置使两者分别处于煤层底板和煤层顶板;根据分段水力压裂参数设计启动并控制高压大流量集中供液装置开始压裂,调节压裂压力至高于压裂泵泵压Pw,完成压裂水量V时停止第1个分支孔压裂;拖动电磁传输高压密封管柱使钻头处于第2个分支孔开孔点,第2个开孔点距第1个开孔点的距离为O,开始钻进第2个分支孔并进行随钻压裂,重复上述步骤直至所有分支孔压裂完成。
在一些实施例中,其中步骤7压裂后进行排水时,钻孔孔口安装临时负压装置,用于抽吸排水过程中出现的正压瓦斯,防止钻场内部瓦斯超限,排水至排水流量小于VP时采用水泥砂浆封孔,VP在0.2~0.5m3/h内取值,封孔后连接抽采装置进行抽采。
本公开的一种煤矿瓦斯深孔区域化抽采的方法与装置,结构简单,操作简便,在钻进和压裂时共用高压大流量集中供液装置和电磁传输高压密封管柱,随钻雷达地质探测装置无需退钻后再探测,探测结果直接指导钻进过程,钻进过程自主作业,裸眼分段压裂工具串可随钻作业,可实现以松软煤层为主的煤矿井下无巷化大区域瓦斯超前高效抽采。
附图说明
图1为本公开的煤矿瓦斯深孔区域化抽采流程示意图;
图2为本公开的煤矿瓦斯深孔区域化抽采钻孔布置立体示意图;
图3为本公开的煤矿瓦斯深孔区域化抽采装置总体示意图;
图4为本公开的随钻雷达地质探测装置示意图;
图5为本公开的自适应定向钻机主机示意图;
图6为本公开的裸眼随钻分段压裂工具串示意图。
附图标记:1-钻头;2-近钻头随钻测量装置;3-螺杆马达;4-随钻雷达地质探测装置;401-发射共形天线阵列;402-发射机控制电路;403-接收机控制电路;404-雷达信号处理器;405-MEMS加速度传感器;406-接收共形天线阵列;407-煤岩交界面Ⅰ;408-煤岩交界面Ⅱ;5-电磁传输高压密封管柱;6-自适应定向钻机主机;601-锚固油缸组;602-自适应给进装置;603-电动机组件;604-油箱组件;605-自适应动力头;606-防爆电脑;607-履带车平台;701-水箱;702-双泵结构;703-钻进压裂双模式供液切换结构;704-高压胶管;705-孔口装置;706-远程控制器;801-上转换结构;802-上封隔器;803-上扶正器;804-双模式压差滑套筛管一体化短节;805-下扶正器;806-下封隔器;807-下转换结构。
具体实施方式
下面详细描述本公开的实施例,所述实施例的示例在附图中示出。下面通过参考附图描述的实施例是示例性的,旨在用于解释本公开,而不能理解为对本公开的限制。
以下通过特定的具体实例说明本公开的实施方式,本领域技术人员可由本说明书所揭露的内容轻易地了解本公开的其他优点与功效。本公开还可以通过另外不同的具体实施方式加以实施或应用,本说明书中的各项细节也可以基于不同观点与应用,在没有背离本公开的精 神下进行各种修饰或改变。需要说明的是,以下实施例中所提供的图示仅以示意方式说明本公开的基本构想,在不冲突的情况下,以下实施例及实施例中的特征可以相互组合。
其中,附图仅用于示例性说明,表示的仅是示意图,而非实物图,不能理解为对本公开的限制;为了更好地说明本公开的实施例,附图某些部件会有省略、放大或缩小,并不代表实际产品的尺寸;对本领域技术人员来说,附图中某些公知结构及其说明可能省略是可以理解的。
本公开实施例的附图中相同或相似的标号对应相同或相似的部件;在本公开的描述中,需要理解的是,若有术语“上”、“下”、“左”、“右”、“前”、“后”等指示的方位或位置关系为基于附图所示的方位或位置关系,仅是为了便于描述本公开和简化描述,而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作,因此附图中描述位置关系的用语仅用于示例性说明,不能理解为对本公开的限制,对于本领域的普通技术人员而言,可以根据具体情况理解上述术语的具体含义。
图3-6为本公开的煤矿瓦斯深孔区域化抽采装置的总体示意图及各组成部分的示意图。具体而言,煤矿瓦斯深孔区域化抽采装置包括高压大流量集中供液装置、随钻雷达地质探测装置4、深孔自适应定向钻机装置、电磁传输高压密封管柱5、裸眼随钻分段压裂工具串。
参见图3,高压大流量集中供液装置由水箱701、双泵结构702、钻进压裂双模式供液切换结构703、高压胶管704、孔口装置705、远程控制器706依次连接。双泵结构702设置有高压小流量泵组、低压大流量泵组,高压小流量泵组和低压大流量泵组共同连接在同一底盘上,共同连接水箱701及远程控制器706。双泵结构702设置有高压小流量泵组、低压大流量泵组,高压小流量泵组和低压大流量泵组共同连接在同一底盘上,共同连接水箱701及远程控制器706。孔口装置705内部有单向阀,一端与电磁传输高压密封管柱5螺纹连接,一端与高压胶管704连接;单向阀与高压胶管704连接的一端设置有旋转输水结构,单向阀控制流体仅能由高压胶管704一侧至电磁传输高压密封管柱5一侧通过,电磁传输高压密封管柱5一侧还设置有压力表、卸压阀;当高压大流量集中供液装置用于压裂时,在水箱701添加压裂液,当高压大流量集中供液装置用于钻进时,在水箱701内添加钻进液。
参见图3,深孔自适应定向钻机装置包括钻头1、近钻头随钻测量装置2、螺杆马达3、自适应定向钻机主机6。钻头1、近钻头随钻测量装置2、螺杆马达3依次连接;螺杆马达3与随钻雷达地质探测装置4连接;自适应定向钻机主机6与电磁传输高压密封管柱5连接,并通过高压胶管704与高压大流量集中供液装置连接。近钻头随钻测量装置2用于测量钻孔轨迹参数,同时接收来自随钻雷达地质探测装置4探测的地质数据信息,通过电磁传输高压密封管柱5将数据信息传输至自适应定向钻机主机6上,经过数据分析及处理后,自适应调节推进力和回转速度。
参见图3,电磁传输高压密封管柱5为无中心管结构,采用电磁感应方式进行信号传输,密封结构承压能力大于高压大流量集中供液装置最高压力,且不影响信号传输。电磁传输高压密封管柱5在钻进过程中为螺杆马达3传输钻进液,在压裂过程中为裸眼随钻分段压裂工具串传输压裂液,在钻进和压裂过程中传输钻机指令信号、反馈随钻雷达地质探测装置4探测结果信息和钻头1的状态信息。高压大流量集中供液装置在双泵结构702出口连接钻进压裂双模式供液切换结构703,并通过孔口装置705连接电磁传输高压密封管柱5。随钻雷达地质探测装置分别与裸眼随钻分段压裂工具串和深孔自适应定向钻机装置的螺杆马达3连接,并通过电磁传输高压密封管柱5传输信号。
参见图3和图4,随钻雷达地质探测装置4包括发射共形天线阵列401、发射机控制电路402、接收机控制电路403、雷达信号处理器404、MEMS加速度传感器405、接收共形天线阵列406。雷达信号处理器404的信号处理过程为:发射共形天线阵列401螺旋式扫描周边全部空间后,形成间断式的雷达反射界面,在三维空间中提取采掘工作面顶底煤岩分界面,为空间剖分提供分层边界;雷达波在煤层中传播,振幅会随着传播距离的增加而衰减,相位也随之偏移,在地层界面,雷达波会出现偏转和反射;通过反射波的振幅强度与相位偏移,利用层析成像理论,反演雷达波路径上的煤层属性,表征煤层的变化信息。对三维空间的剖分具体采用四面体剖分单元,从而离散整个三维空间;对于钻孔附近小尺度的孔径约束,进行区域化加密;在探测边缘区域,增大剖分尺寸。
参见图3和图5,自适应定向钻机主机6为定向钻孔提供推进力和回转动力。自适应定向钻机主机6包括锚固油缸组601、自适应给进装置602、电动机组件603、油箱组件604、自适应动力头605、防爆电脑606、履带车平台607;锚固油缸组601、自适应给进装置602、电动机组件603、油箱组件604、防爆电脑606均集成在履带车平台607上;自适应动力头605位于自适应给进装置602上,为定向钻孔提供回转动力和精确调整螺杆马达3工具面向角角度;自适应给进装置602提供钻孔所需的推进力。
参见图3和图6,裸眼随钻分段压裂工具串包括上转换结构801、上封隔器802、上扶正器803、双模式压差滑套筛管一体化短节804、下扶正器805、下封隔器806、下转换结构807,上述部件依次螺纹连接,其中上转换结构801与随钻雷达地质探测装置4连接,下转换结构807与电磁传输高压密封管柱5连接;上转换结构801、上封隔器802、上扶正器803、双模式压差滑套筛管一体化短节804、下扶正器805、下封隔器806、下转换结构807均设置有电磁传输结构;双模式压差滑套筛管一体化短节804包含双模式压差滑套和筛管两部分,其中双模式压差滑套设置有钻进压裂双模式结构,筛管用于高压水出水。双模式压差滑套通过调节高压大流量集中供液装置的供液压力来自动切换钻进模式和压裂模式,供液压力在Pd以下为钻进模式,供液压力大于Pd时为压裂模式,其中Pd在10~20MPa之间可调。在钻进模式时高压水不进入上封隔器802、下封隔器806和筛管,避免上封隔器802和下封隔器806膨胀以及筛管出水,高压水只进入螺杆马达3并提供动力。在压裂模式时,高压水不进入螺杆马达3,上封隔器802、下封隔器806膨胀封孔,筛管出水进行分段内压裂,压力降至Pd以下时双模式压差滑套关闭压裂模式上封隔器802、下封隔器806,上封隔器802和下封隔器806卸压收缩。裸眼随钻分段压裂工具串还设置有随钻压裂电磁传输通讯结构,并通过电磁传输通讯结构传输数据。
结合图1-2,说明本公开的煤矿瓦斯深孔区域化抽采方法,应用了图3-6所示出的煤矿瓦斯深孔区域化抽采装置。实施例1中的煤矿瓦斯深孔区域化抽采方法,包括以下步骤。
步骤1,获取煤岩层的地质环境、应力状态、物理力学等参数:假设获取到的煤层坚固性系数f1=0.5、顶板坚固性系数f2=2、区段走向长度L=1200m、区段倾向长度N=600m、煤层厚度h=2m、煤岩抗拉强度σt=1.2MPa、煤层埋深H=600m、煤层原始水平最大主应力σH=24MPa、煤层原始水平最小主应力σh=15MPa、孔隙压力P0=0.5MPa,地下介质的相对介电常数εr=6、顶底板岩层吸水系数λ2=0.25。
步骤2,根据获取的煤岩层参数,按下述方法设计抽采钻孔类型及对应钻孔参数。
抽采钻孔类型划分:抽采钻孔类型分为顶板平行定向长钻孔和顶板平行定向长钻孔+分支孔两种类型,设顶板坚固性系数与煤层坚固性系数比值为D,D值为无量纲参数,D的大 小代表顶板通过水力压裂将裂缝扩展到煤层的可能性大小,根据可能性大小判定是否设计分支孔,D按下式计算:
式中,f1为煤层坚固性系数,f2为顶板坚固性系数,经计算D=4。当D>2时采用顶板平行定向长钻孔,当D≤2时,采用顶板平行定向长钻孔+分支孔。本实施例中计算的D>2,因此采用的抽采钻孔类型为顶板平行定向长钻孔。
将顶板平行定向长钻孔层位设计在煤层上方M处,钻孔长度为K,,钻孔间距为P,钻孔个数为B,M、K、P、B值分别按下式计算,其中ε=1m2
M=2h-f2
K=L+30

经计算M=2m,K=1230m,P=25m,B=21.6。
步骤3,采用深孔自适应定向钻机装置,根据步骤2中的抽采钻孔设计参数,基于随钻雷达地质探测装置在钻进过程中实时连续探测地质信息,自适应调节深孔自适应定向钻机装置推进力、回转速度等,以提高钻进效率,降低钻进过程卡钻、抱钻概率,并始终保持钻孔轨迹处于煤层上方M=2m处进行顶板平行定向长钻孔施工。
随钻雷达地质探测装置4实时探测时接收机控制电路403同步发射机控制电路402指令,并通过MEMS加速度传感器405实时感知装置姿态,根据自身姿态启动一组或多组相应的发射共形天线阵列401和接收共形天线阵列406进行探测数据采集工作与数据分析,反演出定向探测钻孔周围地质信息。随钻雷达地质探测装置4将煤岩交界面信息通过电磁传输高压密封管柱5传输给深孔自适应定向钻机装置,在钻进过程中根据煤岩交界面信息实时调整螺杆马达3方位与倾角,保证钻孔设计层位。
随钻雷达探测煤岩交界面目标体深度H按下式计算:
式中,v为电磁波在介质中的波速;t为探测仪器测量的电磁波走时;x为发射共形天线阵列401与接收共形天线阵列406之间距离;v值可用宽角法直接测量,也可根据近似计算公式:
式中,c为光速,εr为地下介质的相对介电常数。
随钻雷达地质探测装置4自身感知方向计算公式如下:
式中,θ为随钻雷达地质探测装置4探测主方向与煤岩交界面法线方向角度;gy为随钻雷达地质探测装置4初始水平径向方向传感轴加速度测量值;gz为随钻雷达地质探测装置4 初始竖直方向传感轴加速度测量值。
步骤4,根据压裂目标煤岩层的地质环境、应力状态、物理力学等参数,计算煤层的破裂压力Pk、压裂泵泵压Pw、压裂水量V,为后续随钻分段压裂作业提供数据。
煤层的破裂压力Pk,按下式计算。
Pk=3σhHt-P0
式中:σh为煤层原始水平最小主应力,σH为煤层原始水平最大主应力,σt为煤岩抗拉强度,P0为孔隙压力。通过计算煤层的破裂压力Pk=21.7MPa。
根据计算的Pk值及其他参数计算需要的压裂泵泵压Pw,Pw按下式计算。
Pw=Pk+PH+Pr
PH为压裂管路液柱压力,PH=ρgHc;ρ为压裂液密度,本次假设采用清水作为压裂液ρ=1000kg/m3;g为重力加速度,取g=10N/kg;Hc为电磁传输高压密封管柱高差,根据经验的开孔高度1m,结合煤层厚度和钻孔层位值,钻孔终孔标高减去开口标高计算得Hc=3m,经计算PH=0.03MPa;Pr为压裂液沿程摩阻,Pr=aLgλ1,Lg为管路长度,假设为0.1km,λ1为摩阻系数,假设管路摩阻系数λ1=8,a=1MPa/km,计算得Pr=0.8MPa。经计算压裂泵泵压Pw=22.53MPa。
依据压裂目标煤岩层设计的钻孔间距等参数,考虑压力水漏失,估算压裂水量V
V按下式计算:
V=0.02Vλ2
式中V为设计的压裂影响范围煤层体积,根据钻孔间距分段参数等估算的煤层体积约为2250m3;λ2为顶底板岩层吸水系数,依顶板岩层坚固性系数f2取值:f2>2时,λ2取值1,f2为其它数值时,λ2=1.7-0.35f2。经计算V=45m3
步骤5,计算顶板平行定向长钻孔压裂分段长度W和压裂段间距U。
顶板平行定向长钻孔压裂分段长度W和压裂段间距U按下式计算:

上式中,f1为煤层坚固性系数,f2为顶板坚固性系数,M为定向长钻孔距煤层距离,h为煤层厚度,β=1m3/2。经计算顶板平行定向长钻孔压裂分段长度W=5m,压裂段间距U=40m。
步骤6,根据上述设计参数进行水力压裂作业。
顶板平行定向长钻孔随钻压裂作业:利用整套煤矿瓦斯深孔区域化抽采装置进行钻孔施工前,调节好双模式压差滑套筛管一体化短节804来控制上封隔器802与下封隔器806之间的间距至W=5m。顶板平行定向长钻孔施工完后,根据分段水力压裂参数设计启动并控制高压大流量集中供液装置开始压裂,调节压裂压力至高于压裂泵泵压Pw=22.53MPa,完成压裂水量V=45m3时停止孔底第1段压裂,拖动电磁传输高压密封管柱5带动裸眼随钻分段压裂工具串,使上封隔器距第1段压裂的下封隔器位置的距离为压裂段间间距U=40m进行第2段压裂,重复以此直至所有分段压裂完成。
步骤7,压裂后进行排水、封孔、连接抽采装置进行抽采,压裂后进行排水时,孔口安装临时负压装置,用于抽吸排水过程中的正压瓦斯,防止钻场内部瓦斯超限,排水至排水流量小于VP时采用水泥砂浆封孔,VP在0.2~0.5m3/h内取值,封孔后连接抽采装置进行抽采。压裂后,排水、封孔、连接抽采装置进行抽采。
实施例2中的煤矿瓦斯深孔区域化抽采方法,包括以下步骤:
步骤1,获取煤岩层的地质环境、应力状态、物理力学等参数:假设获取到的煤层坚固性系数f1=1.5、顶板坚固性系数f2=2.4、区段走向长度L=1200m、区段倾向长度N=600m、煤层厚度h=2m、煤岩抗拉强度σt=1.2MPa、煤层埋深H=600m、煤层原始水平最大主应力σH=24MPa、煤层原始水平最小主应力σh=15MPa、孔隙压力P0=0.5MPa,地下介质的相对介电常数εr=6、顶底板岩层吸水系数λ2=0.25。
步骤2,根据获取的煤岩层参数,按下述方法设计抽采钻孔类型及对应钻孔参数。
抽采钻孔类型划分:抽采钻孔类型分为顶板平行定向长钻孔和顶板平行定向长钻孔+分支孔两种类型,设顶板坚固性系数与煤层坚固性系数比值为D,D值为无量纲参数,D的大小代表顶板通过水力压裂将裂缝扩展到煤层的可能性大小,根据可能性大小判定是否设计分支孔,D按下式计算:
式中,f1为煤层坚固性系数,f2为顶板坚固性系数,经计算D=1.6。。当D>2时采用顶板平行定向长钻孔,当D≤2时,采用顶板平行定向长钻孔+分支孔。本实施例计算的D值小于2,因此采用的抽采钻孔类型为顶板平行定向长钻孔+分支孔。
将顶板平行定向长钻孔层位设计在煤层上方M处,钻孔长度为K,,钻孔间距为P,钻孔个数为B,M、K、P、B值分别按下式计算,其中ε=1m2
M=2h-f2
K=L+30

经计算M=1.6m,K=1230m,P=31..25m,B=17.28。
顶板平行定向长钻孔+分支孔参数:顶板平行定向长钻孔层位在煤层上方M处,钻孔长度为K,钻孔间距为P,钻孔个数为B,分支钻孔间距O=P=31.25m,分支孔个数为q,q按下式计算:
经计算q=39.36m。
步骤3,采用深孔自适应定向钻机装置,根据步骤2中的抽采钻孔设计参数,基于随钻雷达地质探测装置在钻进过程中实时连续探测地质信息,自适应调节深孔自适应定向钻机装置推进力、回转速度等,以提高钻进效率,降低钻进过程卡钻、抱钻概率,并始终保持钻孔轨迹处于煤层上方M=1.6m处进行顶板平行定向长钻孔施工。
随钻雷达地质探测装置4实时探测时接收机控制电路403同步发射机控制电路402指令,并通过MEMS加速度传感器405实时感知装置姿态,根据自身姿态启动一组或多组相应的发射共形天线阵列401和接收共形天线阵列406进行探测数据采集工作与数据分析,反演出定向探测钻孔周围地质信息。随钻雷达地质探测装置4将煤岩交界面信息通过电磁传输高压密封管柱5传输给深孔自适应定向钻机装置,在钻进过程中根据煤岩交界面信息实时调整螺杆马达3方位与倾角,保证钻孔设计层位。
随钻雷达地质探测装置4探测煤岩交界面目标体深度H按下式计算:
式中,v为电磁波在介质中的波速;t为探测仪器测量的电磁波走时;x为发射共形天线阵列401与接收共形天线阵列406之间距离;v值可用宽角法直接测量,也可根据近似计算公式计算:
式中,c为光速,εr为地下介质的相对介电常数。
随钻雷达地质探测装置4自身感知方向计算公式如下:
式中,θ为随钻雷达地质探测装置4探测主方向与煤岩交界面法线方向角度;gy为随钻雷达地质探测装置4初始水平径向方向传感轴加速度测量值;gz为随钻雷达地质探测装置4初始竖直方向传感轴加速度测量值。
步骤4,根据压裂目标煤岩层的地质环境、应力状态、物理力学等参数,计算煤层的破裂压力Pk、压裂泵泵压Pw、压裂水量V,为后续随钻分段压裂作业提供数据。
煤层的破裂压力Pk,按下式计算:
Pk=3σhHt-P0
上式中:σh为煤层原始水平最小主应力,σH为煤层原始水平最大主应力,σt为煤岩抗拉强度,P0为孔隙压力。通过计算煤层的破裂压力Pk=21.7MPa。
根据计算的Pk值及其他参数计算需要的压裂泵泵压Pw,Pw按下式计算。
Pw=Pk+PH+Pr
PH为压裂管路液柱压力,PH=ρgHc;ρ为压裂液密度,本次假设采用清水作为压裂液ρ=1000kg/m3;g为重力加速度,取g=10N/kg;Hc为电磁传输高压密封管柱高差,由开孔在煤层,最终分支孔进入煤层,高差忽略不计,因此按PH=0MPa计算;Pr为压裂液沿程摩阻,Pr=aLgλ1,Lg为管路长度,假设为0.1km,λ1为摩阻系数,假设管路摩阻系数λ1=8,计算得Pr=0.8MPa。经计算压裂泵泵压Pw=22.5MPa。
依据压裂目标煤岩层设计的钻孔间距等参数,考虑压力水漏失,估算压裂水量V
V按下式计算:
V=0.02Vλ2
式中V为设计的压裂影响范围煤层体积,根据钻孔间距分段参数等估算的煤层体积约 为1953m3;λ2为顶底板岩层吸水系数,依顶板岩层坚固性系数f2取值,f2>2时,λ2取值为1,f2为其它数值时,λ2=1.7-0.35f2。经计算V=39.06m3
步骤5,计算顶板平行定向长钻孔压裂分段长度W和压裂段间距U,本次选用的钻孔类型为顶板平行定向长钻孔+分支孔,因此该步骤无需进行计算。
步骤6,根据上述设计参数进行水力压裂作业。
顶板平行定向长钻孔+分支孔随钻压裂作业:利用整套煤矿瓦斯深孔区域化抽采装置进行钻孔施工前,调节好双模式压差滑套筛管一体化短节804来控制上封隔器802与下封隔器806之间的间距,使其大于钻孔在煤层段内的预计长度,顶板平行定向长钻孔施工完后,在孔底开始施工第1个分支孔,施工完后调整上封隔器802与下封隔器806的位置使其分别处于煤层底板和煤层顶板。根据分段水力压裂参数设计启动并控制高压大流量集中供液装置开始压裂,调节压裂压力至高于压裂泵泵压Pw=22.5MPa,完成压裂水量V=39.06m3时停止第1个分支孔压裂。拖动电磁传输高压密封管柱5使钻头处于第2个分支孔开孔点,第2个开孔点距第1个开孔点的距离为O=31.25m,开始钻进第2个分支孔并进行随钻压裂,重复以此直至所有分支孔压裂完成。
步骤7,压裂后进行排水、封孔、连接抽采装置进行抽采,压裂后进行排水时,孔口安装临时负压装置,用于抽吸排水过程中的正压瓦斯,防止钻场内部瓦斯超限,排水至排水流量小于VP时采用水泥砂浆封孔,VP在0.2~0.5m3/h内取值,封孔后连接抽采装置进行抽采。压裂后,排水、封孔、连接抽采装置进行抽采。
如上所述,结合附图所给出的方案内容,可以衍生出类似的方案,但凡对本公开的技术方案进行修改或者等同替换,而不脱离本技术方案的宗旨和范围,其均应涵盖在本公开的权利要求范围当中。
在本公开的描述中,需要理解的是,术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”“内”、“外”、“顺时针”、“逆时针”、“轴向”、“径向”、“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系,仅是为了便于描述本公开和简化描述,而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作,因此不能理解为对本公开的限制。
此外,术语“第一”、“第二”仅用于描述目的,而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此,限定有“第一”、“第二”的特征可以明示或者隐含地包括至少一个该特征。在本公开的描述中,“多个”的含义是至少两个,例如两个,三个等,除非另有明确具体的限定。
在本公开中,除非另有明确的规定和限定,术语“安装”、“相连”、“连接”、“固定”等术语应做广义理解,例如,可以是固定连接,也可以是可拆卸连接,或成一体;可以是机械连接,也可以是电连接或彼此可通讯;可以是直接相连,也可以通过中间媒介间接相连,可以是两个元件内部的连通或两个元件的相互作用关系,除非另有明确的限定。对于本领域的普通技术人员而言,可以根据具体情况理解上述术语在本公开中的具体含义。
在本公开中,除非另有明确的规定和限定,第一特征在第二特征“上”或“下”可以是第一和第二特征直接接触,或第一和第二特征通过中间媒介间接接触。而且,第一特征在第二特征“之上”、“上方”和“上面”可是第一特征在第二特征正上方或斜上方,或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”可 以是第一特征在第二特征正下方或斜下方,或仅仅表示第一特征水平高度小于第二特征。
在本公开中,术语“一个实施例”、“一些实施例”、“示例”、“具体示例”、或“一些示例”等意指结合该实施例或示例描述的具体特征、结构、材料或者特点包含于本公开的至少一个实施例或示例中。在本说明书中,对上述术语的示意性表述不必须针对的是相同的实施例或示例。而且,描述的具体特征、结构、材料或者特点可以在任一个或多个实施例或示例中以合适的方式结合。此外,在不相互矛盾的情况下,本领域的技术人员可以将本说明书中描述的不同实施例或示例以及不同实施例或示例的特征进行结合和组合。
尽管已经示出和描述了上述实施例,可以理解的是,上述实施例是示例性的,不能理解为对本公开的限制,本领域普通技术人员对上述实施例进行的变化、修改、替换和变型均在本公开的保护范围内。

Claims (26)

  1. 一种煤矿瓦斯深孔区域化抽采装置,包括:高压大流量集中供液装置、随钻雷达地质探测装置(4)、深孔自适应定向钻机装置、电磁传输高压密封管柱(5)、裸眼随钻分段压裂工具串;
    所述高压大流量集中供液装置设置有双泵结构(702),双泵结构(702)出口连接钻进压裂双模式供液切换结构(703),所述高压大流量集中供液装置连接所述电磁传输高压密封管柱(5);所述电磁传输高压密封管柱(5)为裸眼随钻分段压裂工具串提供压裂液,为深孔自适应定向钻机装置的螺杆马达(3)提供钻进液;所述随钻雷达地质探测装置(4)分别与所述裸眼随钻分段压裂工具串和深孔自适应定向钻机装置的所述螺杆马达(3)连接,并通过所述电磁传输高压密封管柱(5)传输信号;所述裸眼随钻分段压裂工具串设置有随钻压裂电磁传输通讯结构和双模式压差滑套,通过电磁传输通讯结构传输数据,通过双模式压差滑套切换钻进模式和压裂模式。
  2. 根据权利要求1所述的煤矿瓦斯深孔区域化抽采装置,其中,所述高压大流量集中供液装置由水箱(701)、所述双泵结构(702)、所述钻进压裂双模式供液切换结构(703)、高压胶管(704)、孔口装置(705)、远程控制器(706)依次连接。
  3. 根据权利要求2所述的煤矿瓦斯深孔区域化抽采装置,其中,所述双泵结构(702)设置有高压小流量泵组、低压大流量泵组,高压小流量泵组和低压大流量泵组共同连接在同一底盘上,共同连接所述水箱(701)及所述远程控制器(706)。
  4. 根据权利要求2所述的煤矿瓦斯深孔区域化抽采装置,其中,所述孔口装置(705)内部有单向阀,所述单向阀的一端与所述电磁传输高压密封管柱(5)螺纹连接,所述单向阀的另一端与所述高压胶管(704)连接;所述单向阀与所述高压胶管(704)连接的一端设置有旋转输水结构,所述单向阀控制流体仅能由高压胶管(704)一侧至所述电磁传输高压密封管柱(5)一侧通过,所述电磁传输高压密封管柱(5)一侧还设置有压力表和卸压阀;当所述高压大流量集中供液装置用于压裂时,在所述水箱(701)内添加压裂液,当所述高压大流量集中供液装置用于钻进时,在所述水箱(701)内添加钻进液。
  5. 根据权利要求1所述的煤矿瓦斯深孔区域化抽采装置,其中,深孔自适应定向钻机装置包括钻头(1)、近钻头随钻测量装置(2)、螺杆马达(3)、自适应定向钻机主机(6)。
  6. 根据权利要求5所述的煤矿瓦斯深孔区域化抽采装置,其中,所述近钻头随钻测量装置(2)用于测量钻孔轨迹参数,同时接收来自所述随钻雷达地质探测装置(4)探测的地质数据信息,通过所述电磁传输高压密封管柱(5)将数据信息传输至所述自适应定向钻机主机(6)上,经过数据分析及处理后,自适应调节推进力和回转速度。
  7. 根据权利要求5所述的煤矿瓦斯深孔区域化抽采装置,其中,所述钻头(1)、所述近钻头随钻测量装置(2)、所述螺杆马达(3)依次连接;所述螺杆马达(3)与所述随钻雷达地质探测装置(4)连接;所述自适应定向钻机主机(6)与所述电磁传输高压密封管柱(5)连接,并通过高压胶管(704)与所述高压大流量集中供液装置连接。
  8. 根据权利要求5所述的煤矿瓦斯深孔区域化抽采装置,其中,所述自适应定向钻机主机(6)包括锚固油缸组(601)、自适应给进装置(602)、电动机组件(603)、油箱组件(604)、自适应动力头(605)、防爆电脑(606)、履带车平台(607);所述锚固油缸组(601)、所述自适应给进装置(602)、所述电动机组件(603)、所述油箱组件(604)、所述防爆电脑(606)均集成在所述履带车平台(607)上;所述自适应动力头(605)位于所述自适应给进装置(602)上,为定向钻孔 提供回转动力并精确调整所述螺杆马达(3)工具面向角角度;所述自适应给进装置(602)提供钻孔所需的推进力。
  9. 根据权利要求1所述的煤矿瓦斯深孔区域化抽采装置,其中,所述电磁传输高压密封管柱(5)为无中心管结构,采用电磁感应方式进行信号传输,密封结构承压能力大于高压大流量集中供液装置最高压力,且不影响信号传输。
  10. 根据权利要求9所述的煤矿瓦斯深孔区域化抽采装置,其中,所述电磁传输高压密封管柱(5)在钻进过程中为所述螺杆马达(3)传输钻进液,在压裂过程中为所述裸眼随钻分段压裂工具串传输压裂液,在钻进和压裂过程中传输钻机指令信号并反馈所述随钻雷达地质探测装置(4)探测结果信息和钻头(1)的状态信息。
  11. 根据权利要求1所述的煤矿瓦斯深孔区域化抽采装置,其中,所述裸眼随钻分段压裂工具串包括上转换结构(801)、上封隔器(802)、上扶正器(803)、双模式压差滑套筛管一体化短节(804)、下扶正器(805)、下封隔器(806)、下转换结构(807),其中上转换结构(801)与随钻雷达地质探测装置(4)连接,下转换结构(807)与电磁传输高压密封管柱(5)连接;所述上转换结构(801)、所述上封隔器(802)、所述上扶正器(803)、所述双模式压差滑套筛管一体化短节(804)、所述下扶正器(805)、所述下封隔器(806)、所述下转换结构(807)均设置有电磁传输结构;所述双模式压差滑套筛管一体化短节(804)包含双模式压差滑套和筛管两部分,其中所述双模式压差滑套设置有钻进压裂双模式结构,筛管用于高压水出水。
  12. 根据权利要求11所述的煤矿瓦斯深孔区域化抽采装置,其中,所述双模式压差滑套通过调节所述高压大流量集中供液装置的供液压力自动切换钻进模式和压裂模式,供液压力在Pd以下时为钻进模式,供液压力大于Pd时为压裂模式,其中Pd在10~20MPa之间可调。
  13. 根据权利要求12所述的煤矿瓦斯深孔区域化抽采装置,其中,在钻进模式时高压水不进入所述上封隔器(802)、所述下封隔器(806)和所述筛管,避免所述上封隔器(802)和所述下封隔器(806)膨胀以及所述筛管出水,高压水只进入所述螺杆马达(3)并提供动力;在压裂模式时,高压水不进入所述螺杆马达(3),所述上封隔器(802)、所述下封隔器(806)膨胀封孔,所述筛管出水进行分段内压裂,压力降至Pd以下时,所述双模式压差滑套关闭压裂模式所述上封隔器(802)、所述下封隔器(806),所述上封隔器(802)和所述下封隔器(806)卸压收缩。
  14. 根据权利要求1所述的煤矿瓦斯深孔区域化抽采装置,其中,所述随钻雷达地质探测装置(4)包括发射共形天线阵列(401)、发射机控制电路(402)、接收机控制电路(403)、雷达信号处理器(404)、MEMS加速度传感器(405)、接收共形天线阵列(406)。
  15. 根据权利要求14所述的煤矿瓦斯深孔区域化抽采装置,其中,所述雷达信号处理器(404)对信号的处理过程为:所述发射共形天线阵列(401)螺旋式扫描周边全部空间后,形成间断式的雷达反射界面,在三维空间中提取采掘工作面顶底煤岩分界面,为空间剖分提供分层边界;雷达波在煤层中传播,振幅会随着传播距离的增加而衰减,相位也随之偏移,在地层界面,雷达波会出现偏转和反射;通过反射波的振幅强度与相位偏移,利用层析成像理论,反演雷达波路径上的煤层属性,表征煤层的变化信息。
  16. 根据权利要求15所述的煤矿瓦斯深孔区域化抽采装置,其中,对所述三维空间的剖分采用四面体剖分单元,从而离散整个三维空间;对于钻孔附近小尺度的孔径约束,进行区域化加密;在探测边缘区域,增大剖分尺寸。
  17. 一种煤矿瓦斯深孔区域化抽采方法,应用如权利要求1~16中任一项所述的一种煤 矿瓦斯深孔区域化抽采装置,包括:
    步骤1,获取煤岩层的地质环境、应力状态和物理力学参数,所述煤岩层的参数包括煤层坚固性系数f1、顶板坚固性系数f2、区段走向长度L、区段倾向长度N、煤层厚度h、煤岩抗拉强度σt、煤层埋深H、煤层原始水平最大主应力σH、煤层原始水平最小主应力σh、孔隙压力P0、地下介质的相对介电常数εr、顶底板岩层吸水系数λ2
    步骤2,根据获取的煤岩层的参数和设计公式设计抽采钻孔类型及对应钻孔参数;
    步骤3,采用深孔自适应定向钻机装置,根据步骤2中设置的抽采钻孔参数,基于随钻雷达地质探测装置(4)在钻进过程中实时连续探测的地质信息,自适应调节深孔自适应定向钻机装置的推进力和回转速度,进行顶板平行定向长钻孔施工;
    步骤4,根据压裂目标煤岩层的参数,计算煤层的破裂压力Pk、压裂泵泵压Pw以及压裂水量V
    步骤5,计算顶板平行定向长钻孔压裂分段长度W和压裂段间距U;
    步骤6,以步骤4和步骤5得到的参数作为设计参数进行水力压裂作业;
    步骤7,压裂后进行排水、封孔,连接抽采装置进行抽采。
  18. 根据权利要求17所述的煤矿瓦斯深孔区域化抽采方法,其中步骤2的抽采钻孔类型设计方法如下:
    抽采钻孔类型分为顶板平行定向长钻孔和顶板平行定向长钻孔+分支孔两种类型,设顶板坚固性系数f2与煤层坚固性系数f1比值为D,D按下式计算:
    其中D>2时采用顶板平行定向长钻孔,D≤2时,采用顶板平行定向长钻孔+分支孔。
  19. 根据权利要求18所述的煤矿瓦斯深孔区域化抽采方法,其中步骤2的抽采钻孔类型对应的钻孔参数设计方法如下:
    分支孔施工时钻头(1)穿过煤层并进入底板深度为x,x取值为5~10m;
    顶板平行定向长钻孔参数:顶板平行定向长钻孔层位在煤层上方M处,钻孔长度为K,钻孔间距为P,钻孔个数为B,M、K、P、B值分别按下式计算,其中ε=1m2
    M=2h-f2
    K=L+30

    顶板平行定向长钻孔+分支孔参数:顶板平行定向长钻孔层位在煤层上方M处,钻孔长度为K,钻孔间距为P,钻孔主孔个数为B,分支钻孔间距O=P,分支孔个数为q,q按下式计算:
  20. 根据权利要求17所述的煤矿瓦斯深孔区域化抽采方法,其中步骤3中的随钻雷达地质探测装置(4)在钻进过程中实时连续探测,具体过程为:探测时,接收机控制电路(403)同步发射机控制电路(402)的指令,并通过MEMS加速度传感器(405)实时感知随钻雷达地质探测装置(4)姿态,根据自身姿态启动一组或多组相应的发射共形天线阵列(401)和接收共形天线阵列(406)进行探测数据采集工作与数据分析,反演出定向探测钻孔周围地质信息;随钻雷达地质探测装置(4)将煤岩交界面信息通过电磁传输高压密封管柱(5)传输给深孔自适应定向钻机装置,在钻进过程中根据煤岩交界面信息实时调整螺杆马达(3)方位与倾角,保证钻孔设计层位。
  21. 根据权利要求20所述的煤矿瓦斯深孔区域化抽采方法,其中随钻雷达地质探测装置(4)探测煤岩交界面目标体深度H计算公式如下:
    上式中,v为电磁波在介质中的波速;t为探测仪器测量的电磁波走时;x为发射共形天线阵列(401)与接收共形天线阵列(406)之间的距离;v值可用宽角法直接测量或根据近似计算公式计算:
    上式中,c为光速,εr为地下介质的相对介电常数;
    随钻雷达地质探测装置(4)自身感知方向计算公式如下:
    上式中,θ为随钻雷达地质探测装置(4)探测主方向与煤岩交界面法线方向角度;gy为随钻雷达地质探测装置(4)初始水平径向方向传感轴加速度测量值;gz为随钻雷达地质探测装置(4)初始竖直方向传感轴加速度测量值。
  22. 根据权利要求17所述的煤矿瓦斯深孔区域化抽采方法,其中步骤4中煤层的破裂压力Pk,计算公式如下:
    Pk=3σhHt-P0
    上式中:σh为煤层原始水平最小主应力,σH为煤层原始水平最大主应力,σt为煤岩抗拉强度,P0为孔隙压力;
    计算需要的压裂泵泵压Pw,Pw计算公式如下:
    Pw=Pk+PH+Pr
    上式中:PH为压裂管路液柱压力,PH=ρgHc,ρ为压裂液密度;g为重力加速度,Hc为电磁传输高压密封管柱(5)高差,为钻孔终孔标高减去开口标高;Pr为压裂液沿程摩阻,Pr=aLgλ1,Lg为管路长度,λ1为摩阻系数,a=1MPa/km;
    依据压裂目标煤岩层设计的钻孔间距参数,考虑压力水漏失,估算压裂水量V
    V计算公式如下:
    V=0.02Vλ2
    上式中V为设计的压裂影响范围煤层体积;λ2为顶底板岩层吸水系数,根据顶板坚固 性系数f2取值:f2>2时,λ2取值为1,f2为其它数值时,λ2=1.7-0.35f2
  23. 根据权利要求17所述的煤矿瓦斯深孔区域化抽采方法,其中步骤5中顶板平行定向长钻孔压裂分段长度W和压裂段间距U按下式计算:

    上式中,f1为煤层坚固性系数,f2为顶板坚固性系数,M为定向长钻孔距煤层距离,h为煤层厚度,β=1m3/2
  24. 根据权利要求17所述的煤矿瓦斯深孔区域化抽采方法,其中步骤6根据设计参数进行水力压裂作业,对于顶板平行定向长钻孔随钻压裂作业,具体步骤如下:
    利用煤矿瓦斯深孔区域化抽采装置进行钻孔施工前,调节好双模式压差滑套筛管一体化短节(804)来控制上封隔器(802)与下封隔器(806)之间的间距至顶板平行定向长钻孔压裂分段长度W;
    顶板平行定向长钻孔施工完成后,根据分段水力压裂参数设计启动并控制高压大流量集中供液装置开始压裂,调节压裂压力至高于压裂泵泵压Pw,完成压裂水量V时停止孔底第1段压裂,拖动电磁传输高压密封管柱(5)带动裸眼随钻分段压裂工具串,使上封隔器(802)距第1段压裂的下封隔器(806)位置的距离为压裂段间距U进行第2段压裂,重复上述步骤直至所有分段压裂完成。
  25. 根据权利要求17所述的煤矿瓦斯深孔区域化抽采方法,其中步骤6根据设计参数进行水力压裂作业,对于顶板平行定向长钻孔+分支孔随钻压裂作业,具体步骤如下:
    利用煤矿瓦斯深孔区域化抽采装置进行钻孔施工前,调节好双模式压差滑套筛管一体化短节(804)来控制上封隔器(802)与下封隔器(806)之间的间距,使该间距大于钻孔在煤层段内的长度,顶板平行定向长钻孔施工完后,在孔底开始施工第1个分支孔,施工完成后调整上封隔器(802)与下封隔器(806)的位置使两者分别处于煤层底板和煤层顶板;根据分段水力压裂参数设计启动并控制高压大流量集中供液装置开始压裂,调节压裂压力至高于压裂泵泵压Pw,完成压裂水量V时停止第1个分支孔压裂;拖动电磁传输高压密封管柱(5)使钻头(1)处于第2个分支孔开孔点,第2个开孔点距第1个开孔点的距离为O,开始钻进第2个分支孔并进行随钻压裂,重复上述步骤直至所有分支孔压裂完成。
  26. 根据权利要求17所述的煤矿瓦斯深孔区域化抽采方法,其中步骤7压裂后进行排水时,钻孔孔口安装临时负压装置,用于抽吸排水过程中出现的正压瓦斯,防止钻场内部瓦斯超限,排水至排水流量小于VP时采用水泥砂浆封孔,VP在0.2~0.5m3/h内取值,封孔后连接抽采装置进行抽采。
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