CN117514108A - Ultrasonic-hydraulic acupoint-making pressure-relief composite fracturing permeability-increasing system and application method - Google Patents

Abstract

The invention provides an ultrasonic-hydraulic hole making pressure relief composite fracturing and permeability increasing system and an application method thereof, wherein the permeability increasing system comprises a drill rod, a drilling machine connected with the drill rod, an ultrasonic transducer arranged in the drill rod and a hydraulic hole making nozzle arranged on the side wall of the drill rod; the drill rod is also provided with a water through pipeline, a hole packer connected with the drill rod and used for sealing a gap between the inner wall of the drill hole and the outer wall of the drill rod is arranged at the orifice of the drill hole, the hole packer is connected with a water inlet pipe communicated with the water through pipeline, and a water inlet valve is arranged on the water inlet pipe; the section of the drill rod provided with the ultrasonic transducer is provided with a water cavity, water can enter the water cavity through a water passage pipeline, and the water in the water passage pipeline or the water cavity can be sprayed to a coal seam through a hydraulic cavity making nozzle to make a cavity. The invention integrates three functions of directional drilling of a drill rod, hydraulic cave-making transformation of macroscopic cracks of a coal body and high-frequency ultrasonic transformation of a micro-seam net structure of the coal body, and can carry out full-aperture structural transformation and infiltration enhancement on macroscopic and microscopic cracks and pores.

Description

Ultrasonic-hydraulic acupoint-making pressure-relief composite fracturing permeability-increasing system and application method

Technical Field

The invention belongs to the technical field of coal seam permeability enhancement, and particularly relates to an ultrasonic-hydraulic acupoint-making pressure-relief composite fracturing permeability-increasing system and an application method thereof.

Background

Most of coal beds in China are high-gas-pressure, high-ground-stress and low-permeability coal beds, gas power phenomenon is serious in the coal bed exploitation process, geological conditions are complex, air permeability of the coal beds is poor, and extraction utilization rate of most of the coal beds is low. In the prior art, the conventional hydraulic fracturing technology cannot control the cracking position and the expansion direction of the coal body cracks, and the crack extension range is smaller, so that the water locking phenomenon is easy to occur, and a gas running channel is blocked.

The hydraulic cave-making method is based on hydraulic coal mining, and is formed by injecting water into a coal body under high pressure, the high pressure water is loaded to act on the coal body to crush the coal body, the crushed coal and released gas are discharged out of a hole, the coal bed generates displacement, the stress is redistributed, the stress near a cave-making cavity is reduced, the number of pore cracks in the coal is obviously increased, and the purposes of releasing the ground stress and improving the air permeability are achieved. For example, CN202010539985.0 discloses a front-end power type hydraulic large-diameter staged hole-making pressure relief and reflection-increasing device and method, which are mainly used for large-diameter hole making in the hydraulic hole-making reflection-increasing process of underground coal seams, staged hole making is realized by disassembling an elongated jet rod, and three-dimensional hole making is realized by transverse rotation of a drill rod and longitudinal rotation of a jet device.

The hydraulic hole making pressure relief has good reconstruction effect on macroscopic cracks of a near hole area, but has general micro-cracks and pore effects on the near hole area, and meanwhile, the capability of reconstructing the macroscopic and microscopic cracks and the pore of a far hole area is very limited, and particularly, the gas extraction effect of the far hole area is limited, so that the improvement is necessary.

Disclosure of Invention

The invention aims to solve the technical problems in the prior art, and the first aim of the invention is to provide an ultrasonic-hydraulic acupoint-creating pressure-relief composite fracturing and permeability-increasing system, and the second aim of the invention is to provide an application method based on the ultrasonic-hydraulic acupoint-creating pressure-relief composite fracturing and permeability-increasing system.

In order to achieve the first object, the present invention adopts the following technical scheme: an ultrasonic-hydraulic hole-making pressure-relief composite fracturing permeability-increasing system is characterized in that a drilling hole is constructed in a coal seam, the drilling hole is a horizontal long drilling hole, and the permeability-increasing system comprises a drill rod, a drilling machine, an ultrasonic transducer and a hydraulic hole-making nozzle, wherein the drilling machine is connected with the drill rod and is positioned outside the drilling hole, the ultrasonic transducer is arranged in the drill rod, and the hydraulic hole-making nozzle is arranged on the side wall of the drill rod; the cable of the ultrasonic transducer passes through the drill rod and is connected with an ultrasonic generating system positioned outside the drill hole; the drill rod is also provided with a water passage pipeline extending along the length direction of the drill rod, a hole packer connected with the drill rod and used for sealing a gap between the inner wall of the drill hole and the outer wall of the drill rod is arranged at the orifice of the drill hole, the hole packer is connected with a water inlet pipe communicated with the water passage pipeline, the water inlet pipe is connected with a water source, and a water inlet valve is arranged on the water inlet pipe; the section of the drill rod provided with the ultrasonic transducer is provided with a water cavity, water can enter the water cavity through a water passage pipeline, and the water in the water passage pipeline or the water cavity can be sprayed to a coal seam through a hydraulic cavity making nozzle to make a cavity.

According to the technical scheme, the drilling machine and the drill rod are used for drilling, the ultrasonic generating system and the ultrasonic transducer are used for implementing ultrasonic anti-reflection, the drill rod can realize dual transportation of water injection and electric conduction in the drill rod, and the hole packer is used for plugging water injection in a drilling hole. The set of permeability increasing system integrates three functions of directional drilling of a drill rod, hydraulic cave-making reconstruction of macroscopic cracks of a coal body and high-frequency ultrasonic reconstruction of a coal body micro-seam net structure, combines two technologies of ultrasonic permeability increasing and hydraulic cave-making pressure relief, and can fully reconstruct far holes and near holes to avoid permeability increasing blank bands; meanwhile, the full-aperture structural transformation and permeation enhancement can be carried out on macro-aperture cracks and micro-aperture cracks.

In a preferred embodiment of the invention, a through hole communicated with the water cavity is arranged on the side wall of the drill rod, and a valve for closing or opening the through hole is arranged in the drill rod; the valve comprises a baffle plate arranged on the inner wall of the drill rod and a driving mechanism for driving the baffle plate to move so as to open or close the through hole, and the driving mechanism drives the baffle plate to move along the axial direction and/or the circumferential direction of the drill rod so as to open or close the through hole.

According to the technical scheme, when the drill rod is conveyed into the drill hole through the drilling machine, the valve is closed, so that particles in the drill hole can be prevented from entering the drill rod through the through hole, and the through hole can be prevented from being blocked; when the ultrasonic anti-reflection coal bed is adopted, the valve is opened, water in the water passage is injected into the drill hole through the through hole, so that the ultrasonic anti-reflection operation is carried out in the hydraulic environment, the propagation of ultrasonic waves emitted by the ultrasonic transducer and the formation of ultrasonic cavitation jet effect are facilitated, and the anti-reflection effect is better.

In a preferred embodiment of the invention, the hole packer is sleeved outside the drill rod, the water inlet of the water passage pipeline is positioned in the drill rod section in the hole packer, and the side wall of the drill rod section in the hole packer is provided with a flow hole which is communicated with the water inlet of the water passage pipeline and the water outlet of the water inlet pipe at the same time.

In a preferred embodiment of the invention, the hole packer comprises a holder sleeved outside the drill rod and positioned outside the drill hole, and a water injection bag which is connected with the holder and is made of elastic material and positioned in the drill hole, wherein the water injection bag is sleeved outside the drill rod and used for sealing a gap between the inner wall of the drill hole and the outer wall of the drill rod; the water inlet pipe is arranged on the clamp holder, the clamp holder is also provided with a water injection port communicated with the bag, and the water injection port is provided with a water injection valve.

According to the technical scheme, water enters the water injection bag through the water injection pipe, the water injection bag expands, and a gap between the outer wall of the drill rod and the inner wall of the drill hole is sealed, so that the hole opening of the drill hole is closed.

In a preferred embodiment of the invention, a pressure sensor for detecting the pressure in the borehole is mounted on the drill rod; and/or the hole packer is also connected with water pressure monitoring equipment for monitoring water injection pressure in the drill hole.

According to the technical scheme, the pressure sensor is used for monitoring and recording the pressure change in the drill hole in real time, so that the hydraulic pressure monitoring equipment is beneficial to monitoring the water pressure change in the drill hole in real time.

In another preferred embodiment of the invention, the drill rod comprises a plurality of sections of sub drill rods which are sequentially connected, wherein each sub drill rod comprises a front terminal drill rod connected with a drill bit, a containing sub drill rod connected with the front terminal drill rod and used for installing an ultrasonic transducer and a hydraulic cavity-making nozzle, and a water-electricity double-pass sub drill rod which is positioned at the rear side of the ultrasonic transducer and connected with the containing sub drill rod, the water-passing pipeline is divided into a plurality of sections and is respectively arranged in the water-electricity double-pass sub drill rod, the containing sub drill rod is connected with the first section of water-electricity double-pass sub drill rod and the adjacent two sections of water-saving electric double-pass sub drill rods through sealing joints, the sealing joints are provided with conducting structures and pipe connecting structures, cables of the same loop in the adjacent two sections of water-saving electric double-pass sub drill rods are electrically connected through the conducting structures, and the adjacent two sections of water-passing pipelines are connected through the pipe connecting structures.

According to the technical scheme, water injection and conductive double conveying in the drill rod are realized through the hydropower double-photon drill rod; the drill rod consists of a plurality of sections of sub drill rods, a reasonable number of sub drill rods can be arranged according to the length of the drilled holes as required, and the plurality of sections of sub drill rods can be bent, so that the drill rod can be used for directional long drilling, and particularly can be used for drilling horizontal long drilling holes in the coal bed after downwards drilling from the ground to the coal bed.

In another preferred embodiment of the invention, the sealing joint comprises a male joint and a female joint which are fixedly connected with the end parts of the two water-saving electric double-pass sub drill rods respectively, the outer wall of the male joint is in threaded connection with the female joint, and the conductive structure comprises a male joint conductive head which is arranged at the outer end of the male joint and is electrically connected with a cable wire penetrating out of the electric double-pass sub drill rods, and a female joint conductive head which is arranged at the outer end of the female joint and is electrically connected with the cable wire penetrating out of the electric double-pass sub drill rods; the water through pipelines are coaxially arranged in the hydropower double-pass drill rod, and two adjacent water through pipelines are connected through threads, have the same rotation direction as the threads of the male connector and the female connector and have the same screw pitch; when the male connector and the female connector are in threaded connection, the male connector conductive head can be electrically connected with the female connector conductive head, and two adjacent water communication pipelines can be connected into a whole.

According to the technical scheme, after the male connector is spirally connected with the female connector, the male connector conductive head is in electrical contact with the female connector conductive head, so that the circuit is conducted, and when the male connector is in threaded connection with the female connector, two adjacent water communication pipelines are also connected into a whole, so that waterway conduction is realized. The male connector and the female connector are sealed by threads, so that the drill rod is sealed with the outside and the inside at the sealing joint, and the drill rod can be electrified by water and can be placed in liquid for use, such as ultrasonic and hydraulic composite anti-reflection.

In another preferred embodiment of the invention, the male connector conductive head is a conductive ring which is arranged outside the water pipeline and is coaxial with the male connector, and the female connector conductive head is a conductive block which is arranged outside the water pipeline and corresponds to the conductive ring in position; and/or the inner end of the female joint conductive head is fixedly connected with a conductive rod, the inner end of the conductive rod is electrically connected with a cable, a spring is sleeved outside the conductive rod, and the female joint conductive head and the conductive rod are elastically connected with the female joint through the spring; and/or all set up the insulator between water passage way outer wall and the water and electricity bi-pass sub drill rod inner wall, between water passage way outer wall and the male joint inner wall, and between water passage way outer wall and the female joint inner wall, the cable conductor inlays and establishes in the insulator, and conductive structure establishes on the insulator, and the cable conductor in the water and electricity bi-pass sub drill rod passes insulator and conductive structure electric connection.

According to the technical scheme, the male connector conductive head is a conductive ring, and the male connector conductive head and the female connector conductive head can be contacted for conduction no matter the circumferential positions of the male connector and the female connector; by arranging the spring, when errors exist in the machining dimension of the parts, the male connector and the female connector can be still guaranteed to be connected into a whole through threads, the male connector conductive head can be always contacted with the female connector conductive head, and the conduction of an electric loop is guaranteed; the inner wall of the sub drill rod is isolated from the cable, and the water pipeline is isolated from the cable through an insulator, so that the sealing is ensured; and the conductive structure is arranged on the insulator to avoid short circuit.

In order to achieve the second purpose, the invention adopts the following technical scheme: an application method of an ultrasonic-hydraulic acupoint-creating pressure-relief composite fracturing permeation-increasing system comprises the following steps:

selecting a target coal seam, and constructing a borehole in the target coal seam or rock stratum by using a drilling machine;

step two: determining the hole making size and hole making interval, and making a hole making scheme;

step three: connecting an ultrasonic transducer and a hydraulic hole making nozzle with a drill rod, and conveying the drill rod into the bottom of a drilling hole by a drilling machine;

step four: opening a water inlet valve, injecting water into the drill rod through the hole packer, and injecting high-pressure water to the appointed hole making point of the coal seam by a hydraulic hole making nozzle to make the hole;

step five: sealing the hole of the drill hole by using a hole sealer, connecting a cable of an ultrasonic transducer with an ultrasonic generating system, injecting water into the drill hole through the hole sealer and a drill rod, starting water pressure monitoring equipment, and monitoring the water pressure change in the drill hole in real time until the whole drill hole is filled;

step six: after the drill hole is filled with water, an ultrasonic generating system is started, an ultrasonic transducer emits ultrasonic waves, and hydraulic ultrasonic anti-reflection operation is carried out;

step seven: after the hydraulic ultrasonic anti-reflection operation is finished, the ultrasonic generating system is closed, and the ultrasonic operation is stopped;

step eight: after the anti-reflection operation of a section of length in the drilling hole is completed, opening the hole packer, withdrawing a drill rod of a certain length, and circularly operating the steps four to seven until the anti-reflection operation of the last anti-reflection point is finished after the withdrawal;

step nine: and after the anti-reflection is finished, discharging accumulated water in the drill hole, withdrawing the drill rod, and connecting the drill hole into a gas extraction pipeline to perform gas extraction.

According to the technical scheme, hydraulic cave making is firstly carried out to generate a large number of macroscopic fracture structures, and a gas seepage channel in a coal body is opened; and then high-frequency ultrasonic excitation is carried out to assist in generating a large number of micro-gap net structures, so that a gas diffusion channel in the coal body is improved. The large-scale fracture channel formed by hydraulic cavitation is beneficial to the propagation of water in a coal seam, and can strengthen the subsequent ultrasonic cavitation effect; similarly, the high-frequency ultrasonic wave can improve the micro-scale stitch net structure in the coal, and make up the defect of hydraulic hole making in micro-stitch net reconstruction. The hydraulic cave-making cooperated with the ultrasonic wave anti-reflection coal bed can efficiently reform full-scale hole and crack structures in coal, is beneficial to the breaking through of diffusion and seepage channels of gas in the coal body, greatly improves the desorption-diffusion-seepage of the gas in the coal, furthest improves the gas migration channels of the coal bed, solves the problem of limited bottleneck structure of migration, and finally improves the gas extraction quantity.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

fig. 1 is a schematic structural diagram of an ultrasonic-hydraulic cavitation pressure relief composite fracturing and permeability increasing system according to a first embodiment.

Fig. 2 is a schematic view of the drill rod according to the first embodiment.

Fig. 3 is a schematic view of the structure of the ultrasonic transducer installed in the receiving sub drill pipe.

Fig. 4 is a schematic structural view of a sealing joint in the first embodiment.

Fig. 5 is a schematic structural diagram of an ultrasonic-hydraulic cavitation pressure relief composite fracturing and permeability increasing system in the second embodiment.

Reference numerals in the drawings of the specification include: drill pipe 10, front terminal drill pipe 101, accommodation sub drill pipe 102, hydropower bi-pass sub drill pipe 103, drill bit 104, through hole 111, valve 12, shutter 121, driving mechanism 122, connection hole 123, water passage pipe 124, sealing joint 20, male joint 21, female joint 22, male joint conductive head 231, female joint conductive head 232, conductive rod 233, spring 234, stopper 235, insulator 24, ultrasonic transducer 30, hydraulic cavitation nozzle 40, hole packer 50, holder 51, pocket 52, water inlet pipe 53, water inlet valve 54, water injection pipe 55, water injection valve 56, drill 60, cable 70, hydraulic pressure monitoring device 80, computer 90, electric pulse discharge electrode 100, conductive gel injection mechanism 110.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.

In the description of the present invention, it should be understood that the terms "longitudinal," "transverse," "vertical," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate or are based on the orientation or positional relationship shown in the drawings, merely to facilitate description of the invention and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be configured and operated in a particular orientation, and thus should not be construed as limiting the invention.

In the description of the present invention, unless otherwise specified and defined, it should be noted that the terms "mounted," "connected," and "coupled" are to be construed broadly, and may be, for example, mechanical or electrical, or may be in communication with each other between two elements, directly or indirectly through intermediaries, as would be understood by those skilled in the art, in view of the specific meaning of the terms described above.

Example 1

The embodiment provides an ultrasonic-hydraulic hole-making pressure-relief composite fracturing and permeability-increasing system and an application method thereof, wherein a drilling hole is constructed in a coal seam, and the drilling hole is a horizontal long drilling hole. As shown in FIG. 1, in a preferred embodiment, the anti-reflection system includes a drill pipe 10, a drill rig 60 coupled to the drill pipe 10 and located outside of the borehole, an ultrasonic transducer 30 mounted in the drill pipe 10, and a hydraulic cavitation nozzle 40 mounted on a sidewall of the drill pipe 10. Wherein, the cable 70 of the ultrasonic transducer 30 passes through the drill rod 10 to be connected with an ultrasonic generating system (not shown in the figure) located outside the drill hole, one or more ultrasonic transducers 30 are arranged at intervals in the length direction of the drill rod 10, and the plurality of ultrasonic transducers 30 are connected in parallel and/or in series to improve the anti-reflection effect, improve the anti-reflection efficiency and shorten the overall anti-reflection time. The hydraulic cavitation nozzles 40 are mounted on a section of the drill pipe 10 on the front side of the ultrasonic transducer 30, preferably with a plurality of hydraulic cavitation nozzles 40 spaced axially and/or circumferentially along the drill pipe 10.

The drill rod 10 is also provided with a water through pipeline 124 extending along the length direction, a hole packer 50 connected with the drill rod 10 and used for sealing a gap between the inner wall of the drill hole and the outer wall of the drill rod 10 is arranged at the hole opening of the drill hole, the hole packer 50 is connected with a water inlet pipe 53 communicated with the water through pipeline 124, the water inlet pipe 53 is connected with a water source (the water source can be a water pump or a tap), and the water inlet valve 54 is arranged on the water inlet pipe 53. The section of the drill pipe 10 where the ultrasonic transducer 30 is provided has a water chamber into which water can enter through the water passage 124, and the water in the water passage 124 or the water chamber can be injected into the coal seam through the hydraulic cavitation nozzle 40 to cavitate.

The hole packer 50 is sleeved outside the drill pipe 10, the water inlet of the water passage pipeline 124 is positioned in the section of the drill pipe 10 in the hole packer 50, and the side wall of the section of the drill pipe 10 positioned in the hole packer 50 is provided with a circulation hole 111 which is simultaneously communicated with the water inlet of the water passage pipeline 124 and the water outlet of the water inlet pipe 53. The hole packer 50 is also connected with a water pressure monitoring device 80 for monitoring water injection pressure in the drill hole, the water pressure monitoring device 80 is a pressure gauge or a pressure sensor, and a signal output end of the water pressure monitoring device 80 is connected with a computer 90.

By adopting the technical scheme, along with the drilling of the drill bit 104 of the drill rod 10, the ultrasonic transducer 30 and the hydraulic cavity-making nozzle 40 enter deep drilling holes, and the anti-reflection operation is carried out on the coal bed around the drilling holes while the drilling holes are drilled, so that the working efficiency is greatly improved; and the ultrasonic transducer 30 is arranged in the drill rod 10, so that the ultrasonic transducer 30 and the cable 70 thereof can be better protected.

Sealing the hole opening by using a hole packer 50, blocking water injected into the hole, enabling high-pressure water to enter the drill rod 10 from a water pipeline 124, injecting the water to a coal seam by using a hydraulic hole making nozzle 40 to make holes, and releasing the pressure by using the hydraulic hole making nozzle to generate macroscopic cracks in the coal seam; and then the ultrasonic transducer 30 is enabled to transmit ultrasonic waves through the ultrasonic generating system so as to reconstruct micro cracks and pore structures of the coal bed, macroscopic cracks generated by hydraulic cavitation pressure relief are beneficial to the propagation of water in the coal bed, the conduction range of the ultrasonic vibration cavitation effect can be promoted, the ultrasonic action effect and the action radius are further enhanced, and the high-power ultrasonic has a better far-hole reconstruction effect.

As shown in fig. 1, in a preferred embodiment, the packer 50 includes a holder 51 sleeved outside the drill pipe 10 and located outside the drill hole, and a water injection pocket 52 made of an elastic material and connected to the holder 51 and located inside the drill hole, wherein the holder 51 can be fixed on a coal seam outside the drill hole by a flange and bolts, and the water injection pocket 52 is sleeved outside the drill pipe 10 to close a gap between an inner wall of the drill hole and an outer wall of the drill pipe 10. The water inlet pipe 53 is arranged on the clamp holder 51, the clamp holder 51 is also provided with a water injection pipe 55 communicated with the bag 52, and the water injection pipe 55 is provided with a water injection valve 56; when the bore hole is closed, the water injection valve 56 is opened, high pressure water enters the water injection bag 52 through the water injection pipe 55, the water injection bag 52 expands, and the gap between the outer wall of the drill rod 10 and the inner wall of the bore hole is sealed to close the bore hole.

In another preferred embodiment, as shown in fig. 3, a through hole 111 communicating with the water chamber is provided on a side wall of the drill rod 10, and a valve 12 for closing or opening the through hole 111 is installed in the drill rod 10. When the drill rod 10 is conveyed into a drilling hole through the drilling machine 60, the valve 12 is closed, so that particles in the drilling hole can be prevented from entering the drill rod 10 through the through hole 111, and the through hole 111 can be prevented from being blocked by the particles; when hydraulic cavity making is carried out, the valve 12 is closed, water is prevented from flowing out through the through hole 111, high-pressure water is ensured to be sprayed to a coal bed from the hydraulic cavity making nozzle 40 to make cavities, and macroscopic cracks of the coal body are reformed; when the ultrasonic transducer 30 is electrified to enhance the permeability of the coal seam, the valve 12 is opened, and water in the water cavity enters the drill hole through the through hole 111 to perform ultrasonic permeability enhancement in a hydraulic environment.

Specifically, the valve 12 includes a baffle plate 121 disposed on an inner wall of the drill rod 10, and a driving mechanism 122 for driving the baffle plate 121 to move to open or close the through holes 111, for example, a plurality of through holes 111 are disposed on an annular side wall of the drill rod 10 in a matrix, the baffle plate 121 is an annular baffle plate 121, a plurality of connecting holes 123 corresponding to the plurality of through holes 111 are disposed on the baffle plate 121 in a matrix, when the through holes 111 are staggered from the connecting holes 123, the valve 12 is closed, and when the through holes 111 are aligned with the connecting holes 123, the valve 12 is opened. The baffle 121 is axially slidably connected with the inner wall of the drill rod 10, and the driving mechanism 122 is an electric push rod which is mounted on the inner wall of the drill rod 10 and connected with the baffle 121, and the electric push rod drives the baffle 121 to axially move along the drill rod 10 to open or close the through hole 111.

It should be noted that, the baffle 121 may also be slidably connected to the inner wall of the drill pipe 10 in the circumferential direction, and the driving mechanism 122 is also a rotating motor connected to the baffle 121, and the rotating motor drives the baffle 121 to move along the circumferential direction of the drill pipe 10 to open or close the through hole 111; of course, the baffle 121 may also be threadedly coupled to the inner wall of the drill rod 10, and the driving mechanism 122 may drive the baffle 121 to move helically (axially and/or circumferentially) relative to the drill rod 10 to open or close the through-hole 111.

In the present embodiment, the driving mechanism 122 is driven by electric power, and the driving mechanism 122 may be connected in parallel with the ultrasonic transducer 30 and supplied with power by the same cable 70; the driving mechanism 122 and the ultrasonic transducer 30 can also be independently powered, the cable 70 of the driving mechanism 122 and the cable 70 of the ultrasonic transducer 30 can be arranged side by side, and the cable 70 of the driving mechanism and the cable 70 of the ultrasonic transducer 30 are wound together by using insulating tape. Preferably, the drive mechanism 122 may be connected in parallel with the ultrasound transducer 30 and powered by the same cable 70.

In this embodiment, all the ultrasonic transducers 30 and the valves 12 at the corresponding positions thereof may be opened during specific operation, or an ultrasonic sensor or an image sensor may be disposed outside the drill pipe 10 to collect the crack distribution of the coal seam outside the drill pipe, and the valves 12 at the corresponding positions of the ultrasonic transducers 30 and the corresponding positions thereof (or nearest to the coal seam crack) at the coal seam crack are opened to open the corresponding through holes 111 on the side wall of the drill pipe 10. Further improving the anti-reflection efficiency and effectively protecting the ultrasonic transducer 30.

As shown in fig. 2, in the present invention, the drill pipe 10 includes a plurality of sub drill pipes connected in sequence, the sub drill pipes including a front terminal drill pipe 101 connected to a drill bit 104, a receiving sub drill pipe 102 connected to the front terminal drill pipe 101 for mounting the ultrasonic transducer 30 and the hydraulic cavitation nozzle 40, and a hydro-electric bi-pass sub drill pipe 103 connected to the receiving sub drill pipe 102 at the rear side of the ultrasonic transducer 30. The ultrasonic transducer 30 and the hydraulic cavity creation nozzle 40 are respectively installed in two sections of the accommodating sub drill pipes 102, the ultrasonic transducer 30 is located at the rear side of the hydraulic cavity creation nozzle 40, and the two sections of the accommodating sub drill pipes 102 are arranged in close proximity.

In this embodiment, as shown in fig. 4, the water passage pipe 124 is divided into several sections and is respectively disposed in the water and electricity bi-pass sub-drill pipes 103, the housing sub-drill pipe 102 (the drill pipe section where the ultrasonic transducer 30 is installed) is connected with the first water and electricity bi-pass sub-drill pipe 103 and the adjacent two water-saving electric bi-pass sub-drill pipes 103 by the sealing joint 20, the sealing joint 20 is provided with a conductive structure and a pipe connection structure, the cables 70 of the same circuit in the adjacent two water-saving electric bi-pass sub-drill pipes 103 are electrically connected by the conductive structure, and the adjacent two water passage pipes 124 are connected by the pipe connection structure.

In the present invention, the sealing joint may employ the structure disclosed in CN201610014975.9, CN201910498112.7, or the structure disclosed in the present application.

In a preferred embodiment, as shown in fig. 4, the sealing joint 20 comprises a male joint 21 and a female joint 22 which are fixedly connected (such as by bonding or welding) with the ends of two sections of sub drill pipes respectively, wherein the outer wall of the male joint 21 is in threaded connection with the inner wall of the female joint 22, preferably in conical threaded connection, and sealing adhesive tapes are wound at the threaded connection position of the male joint 21 and the female joint 22. When the male connector 21 and the female connector 22 are in threaded connection, the internal conductive structures are in contact, the circuit is conducted, and meanwhile, two adjacent water communication pipelines 124 can be connected into a whole, so that the waterway is conducted.

The water through pipes 124 are coaxially disposed in the water and electricity double-pass sub drill pipe 103, and two adjacent water through pipes 124 are connected by threads, and have the same direction and the same pitch as the threads of the male connector 21 and the female connector 22, so that when the male connector 21 and the female connector 22 are connected into a whole by threads, the two adjacent water through pipes 124 are also connected into a whole, thereby realizing water channel conduction.

The conductive structure includes a male connector conductive head 231 disposed at the outer end of the male connector 21 and electrically connected to the cable 70 penetrating through the hydropower bi-pass drill pipe 103, and a female connector conductive head 232 disposed at the outer end of the female connector 22 and electrically connected to the cable 70 penetrating through the hydropower bi-pass drill pipe 103, wherein the male connector conductive head 231 and the female connector conductive head 232 can be made of copper, and preferably, an anti-corrosion coating, such as tin-bismuth alloy, is added on the male connector conductive head 231 and the female connector conductive head 232. When the male connector 21 and the female connector 22 are screwed together, the male connector conductive head 231 can be in electrical contact with the female connector conductive head 232, so that the circuit is conducted.

In another preferred embodiment, as shown in fig. 4, the male connector conductive head 231 is a conductive ring coaxially arranged with the male connector 21 and annularly arranged outside the water passage 124, and the female connector conductive head 232 is a conductive block corresponding to the conductive ring position and arranged outside the water passage 124.

Further preferably, the inner end (the end close to the hydropower bi-pass drill rod 103) of the female connector conductive head 232 is fixedly connected with a conductive rod 233, the inner end of the conductive rod 233 is electrically connected with the cable 70, a spring 234 is sleeved outside the conductive rod 233, the female connector conductive head 232 and the conductive rod 233 are elastically connected with the female connector 22 together through the spring 234, and a limiting block 235 positioned in the hydropower bi-pass drill rod 103 is fixedly connected on the conductive rod 233 to prevent the female connector conductive head 232 and the conductive rod 233 from being separated from the female connector 22.

In another preferred embodiment, as shown in fig. 4, the insulator 24 is disposed between the outer wall of the water passage 124 and the inner wall of the hydroelectric bi-pipe 103, between the outer wall of the water passage 124 and the inner wall of the male connector 21, and between the outer wall of the water passage 124 and the inner wall of the female connector 22, and the insulator 24 is an insulating gel, such as a white or black insulating gel. The cable 70 is embedded in the insulator 24, the conductive structure is arranged at the outer end of the insulator 24, and the cable 70 in the hydroelectric bi-pass drill rod 103 passes through the insulator 24 to be electrically connected with the conductive structure.

Example two

The structure and principle of this embodiment are basically the same as those of the first embodiment, except that, as shown in fig. 5, an electric pulse discharge electrode 100 and a conductive gel injection mechanism 110 are further built in the drill rod of this embodiment, specifically, a section of accommodating sub drill rod 102 may be further connected to the rear end of the front terminal drill rod 101, the electric pulse discharge electrode 100 and the conductive gel injection mechanism 110 are installed in the accommodating sub drill rod 102 provided with the front side of the hydraulic cavitation nozzle 40, an opening for facilitating the extension and retraction of the conductive gel injection mechanism 110 is provided on the section of accommodating sub drill rod 102, a valve for closing the opening is provided at the opening, and the cable 70 of the electric pulse discharge electrode 100 passes through the drill rod 10 and is connected to an electric pulse generating system (not shown in the drawing) located outside the borehole.

After high-pressure water is sprayed to a coal seam through the hydraulic hole making nozzle 40 to make holes, the stress of the coal seam is redistributed, cracks are generated at the hole making positions, conductive gel is injected into the hole making holes through the conductive gel spraying mechanism 110, the conductive gel enters the cracks through the hole making holes, an electric pulse generating system is started, the electric pulse discharging electrode 100 is aligned to the conductive gel in the hole making holes to discharge directionally, electric energy is transmitted through the conductive gel when the electric pulse discharging electrode 100 discharges, the depth and width of the hole making holes and the cracks are increased, and the permeability increasing effect of macroscopic cracks is improved.

The conductive gel spraying mechanism 110 comprises a telescopic continuum robot and a spraying pipe carried by the continuum robot, the continuum robot is a flexible robot with a plurality of sections of mechanical arms, the shape of the continuum robot is variable, the spraying pipe is carried by the continuum robot, the outlet of the spraying pipe can extend into a crack, conductive gel can be injected into a hole of a coal seam, and electric energy is conveniently transmitted when the electric pulse discharge electrode 100 discharges.

In another preferred embodiment, the electrical pulse discharge electrode 100 comprises a main discharge electrode comprising a telescoping continuum robot and its carried discharge end, which discharges at the target site of the injection of conductive gel, ensuring energy transfer into the coal seam interior along the conductive gel, lengthening the fracture widening. Further preferably, the electric pulse discharge electrode 100 further comprises slave discharge electrodes distributed along the drill rod 10, wherein the discharge energy of the slave discharge electrodes is lower than that of the master discharge electrode, and when the master discharge electrode discharges, the slave discharge electrodes also discharge, so that the boosted energy is more beneficial to the coal seam cracking at the master discharge electrode.

In a more preferred embodiment of the present invention, the amount of the conductive gel sprayed gradually increases as the depth of the slit progresses, and the discharge energy of the main electrode gradually increases. Improving the permeability increasing effect of macroscopic cracks.

In another preferred embodiment, the anti-reflection system further comprises an acoustic wave probe and an acoustic wave receiving means (not shown in the figures). The sound wave exploration device can be placed into the ground through a drill hole in advance, and the direction of the sound wave emitted by the sound wave exploration device is controllable; the sonic receiving device is placed on the ground or in the drill pipe 10 and determines the fracture location, length and width based on the received sonic waves. The method is convenient for judging the positions of the cracks which specifically need to be enhanced in shattering and the width of the coal seam among the cracks.

Example III

The embodiment provides an application method of an ultrasonic-hydraulic acupoint pressure relief composite fracturing and permeability increasing system based on the first embodiment, as shown in fig. 1, the application method comprises the following steps:

selecting a target coal seam, constructing a borehole in the target coal seam or a rock stratum by using a drilling machine 60, arranging a pressure sensor in the middle of a drill rod 10, and monitoring and recording the pressure change in the borehole in real time by using the pressure sensor;

step two: according to the stress data of the pressure sensor and the original gas pressure of the coal seam, remotely simulating the hole making effect by using a computer 90 system, determining the hole making size and hole making interval, and making a hole making scheme;

step three: connecting the ultrasonic transducer 30 and the hydraulic cavity creation nozzle 40 with the drill rod 10, and conveying the drill rod 10 to the bottom of a drilling hole by using the drilling machine 60 according to the sequence of 'a drill bit 104-a front terminal drill rod 101-a containing sub drill rod 102 provided with the hydraulic cavity creation nozzle 40-an ultrasonic transducer provided with the ultrasonic transducer 30-a hydro-electric double-channel drill rod 103';

step four: opening a water inlet valve 54, injecting water into the drill rod 10 through the hole packer 50, and injecting high-pressure water to a designated hole making point of the coal seam by the hydraulic hole making nozzle 40 to make holes;

step five: the hole packer 50 is used for hole sealing, a cable 70 of the ultrasonic transducer 30 is connected with an ultrasonic generation system, a circuit and a waterway are conducted through a hydropower bi-pass drill rod 103, water is injected into a drill hole through the hole packer 50 and the drill rod 10, and the water pressure change in the drill hole is monitored in real time through the water pressure monitoring equipment 80 until the whole drill hole is filled;

step six: after the drill hole is filled with water, the ultrasonic generating system is started by utilizing the remote control of the computer 90, and the ultrasonic transducer 30 emits ultrasonic waves to perform hydraulic ultrasonic anti-reflection operation;

step seven: after the hydraulic ultrasonic anti-reflection operation is finished, the ultrasonic generating system is remotely controlled by the computer 90 to be closed, and the ultrasonic operation is stopped;

step eight: after the anti-reflection operation of a section of length in the drilling hole is completed, opening the hole packer 50, withdrawing the drill rod 10 with a certain length, and circularly operating the steps four to seven until the anti-reflection operation of the last anti-reflection point is completed;

step nine: and after the anti-reflection is finished, discharging accumulated water in the drill hole, withdrawing the drill rod 10, and connecting the drill hole into a gas extraction pipeline for gas extraction.

Example IV

The application method of the ultrasonic-hydraulic acupoint-creating pressure-relief composite fracturing and permeability-increasing system is basically the same as that of the third embodiment, and is different from that of the fourth embodiment in that the acupoint-creating process is different.

As shown in fig. 5, in the present embodiment, the hydraulic cavitation includes the steps of: opening a water inlet valve 54, injecting water into the drill rod 10 through the hole packer 50, and injecting high-pressure water to a designated hole making position of the coal seam by the hydraulic hole making nozzle 40 so as to perform preliminary hole making; the conductive gel injection mechanism 110 injects conductive gel into the acupoint; the method comprises the steps of starting an electric pulse generating system by utilizing remote control of a computer, charging a capacitor to a preset voltage, stopping charging, starting a high-voltage discharge switch of the electric pulse generating system after charging is completed, communicating the capacitor with an electric pulse discharge electrode 100, completing primary directional discharge by aiming at a hole making hole with conductive gel injected by the electric pulse discharge electrode 100, enabling the length of the hole making hole and a crack to be longer and the width to be larger by high-voltage electric pulse discharge, and performing secondary reconstruction of the hole making; after repeating the high-voltage pulse discharging operation a plurality of times, the high-voltage discharging switch of the electric pulse generating system is turned off, and the electric pulse discharging electrode 100 stops working.

Preferably, when the high-voltage pulse discharge is performed for secondary reconstruction of the hole making, the method further comprises the following steps:

s41, transmitting ultrasonic waves to different directions by the acoustic wave probing device, receiving the ultrasonic waves by the acoustic wave receiving device, probing a hole making device existing in the coal bed according to the time difference of transmission and reception, and judging the width and the length of the hole making device by the controller; if the width and length of the holes are lower than the threshold, executing step S42, otherwise judging whether the width of the coal seam between the holes exceeds the threshold, if so, executing step S42, otherwise exiting the program, wherein the middle positions of the two holes are the positions where the cracks are pre-generated;

s42, the controller controls the conductive gel injection mechanism 110 to move and inject conductive gel into the existing hole in the coal seam or at the position where the fracture is pre-generated (namely, the fracture is expected to be generated there);

s43, the controller controls the main discharge electrode of the electric pulse discharge electrode 100 to move to the injection position of the conductive gel and enables the discharge end to be in contact with the conductive gel;

and S44, controlling the main discharge electrode to discharge together with the auxiliary discharge electrode, wherein the discharge intensity of the main discharge electrode is stronger than that of the auxiliary discharge electrode, for example, gaussian distribution type energy distribution can be adopted, the energy of the main discharge electrode is strongest, and the discharge energy of the auxiliary discharge electrode which is farther from the main discharge electrode is lower.

In the description of the present specification, reference to the terms "preferred implementation," "one embodiment," "some embodiments," "example," "a particular example" or "some examples" and the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.

Claims (9)

1. An ultrasonic-hydraulic cave-making pressure-relief composite fracturing permeability-increasing system is characterized by comprising a drill rod, a drilling machine, an ultrasonic transducer and a hydraulic cave-making nozzle, wherein the drilling machine is connected with the drill rod and is positioned outside the drilling hole;

the cable of the ultrasonic transducer passes through the drill rod and is connected with an ultrasonic generating system positioned outside the drill hole;

the drill rod is also provided with a water passage pipeline extending along the length direction of the drill rod, a hole packer connected with the drill rod and used for sealing a gap between the inner wall of the drill rod and the outer wall of the drill rod is arranged at the orifice of the drill hole, the hole packer is connected with a water inlet pipe communicated with the water passage pipeline, the water inlet pipe is connected with a water source, and a water inlet valve is arranged on the water inlet pipe;

the section of the drill rod provided with the ultrasonic transducer is provided with a water cavity, water can enter the water cavity through a water passage pipeline, and the water in the water passage pipeline or the water cavity can be sprayed to a coal seam through the hydraulic cavity making nozzle to make a cavity.

2. The ultrasonic-hydraulic cavitation pressure relief composite fracturing and permeability increasing system according to claim 1, wherein a through hole communicated with the water cavity is arranged on the side wall of the drill rod, and a valve for closing or opening the through hole is arranged in the drill rod;

the valve comprises a baffle plate arranged on the inner wall of the drill rod and a driving mechanism for driving the baffle plate to move so as to open or close the through hole, and the driving mechanism drives the baffle plate to move along the axial direction and/or the circumferential direction of the drill rod so as to open or close the through hole.

3. The ultrasonic-hydraulic hole making pressure relief composite fracturing and permeability increasing system according to claim 1, wherein the hole packer is sleeved outside a drill rod, a water inlet of the water passage pipeline is positioned in a drill rod section in the hole packer, and a side wall of the drill rod section in the hole packer is provided with a flow hole which is simultaneously communicated with the water inlet of the water passage pipeline and the water outlet of the water inlet pipe.

4. The ultrasonic-hydraulic hole making pressure relief composite fracturing and permeability increasing system according to claim 3, wherein the hole packer comprises a holder sleeved outside the drill rod and positioned outside the drill hole, and a water injection bag made of elastic material and connected with the holder and positioned in the drill hole, and the water injection bag is sleeved outside the drill rod and used for sealing a gap between the inner wall of the drill hole and the outer wall of the drill rod;

the water inlet pipe is arranged on the clamp holder, the clamp holder is also provided with a water injection port communicated with the bag, and a water injection valve is arranged at the water injection port.

5. The ultrasonic-hydraulic cavitation pressure relief composite fracturing and permeability increasing system according to any one of claims 1-4, wherein a pressure sensor for detecting pressure in a borehole is installed on the drill rod;

and/or the hole packer is also connected with water pressure monitoring equipment for monitoring water injection pressure in the drill hole.

6. The ultrasonic-hydraulic hole making pressure relief composite fracturing and permeability increasing system according to any one of claims 1-4, wherein the drill rod comprises a plurality of sections of sub drill rods which are sequentially connected, each sub drill rod comprises a front terminal drill rod connected with a drill bit, a containing sub drill rod connected with the front terminal drill rod and used for installing an ultrasonic transducer and a hydraulic hole making nozzle, and a water-electricity double-way sub drill rod connected with the containing sub drill rod, wherein a water passage pipe is divided into a plurality of sections and is respectively arranged in the water-electricity double-way sub drill rod, the containing sub drill rod is connected with a first water-saving electric double-way sub drill rod and two adjacent water-saving electric double-way sub drill rods through sealing joints, the sealing joints are provided with conductive structures and pipe connecting structures, cables of the same circuit in the two adjacent water-saving electric double-way sub drill rods are electrically connected through the conductive structures, and the water passages of two adjacent sections are connected through the pipe connecting structures.

7. The ultrasonic-hydraulic cavitation pressure relief composite fracturing and permeability increasing system according to claim 6, wherein the sealing joint comprises a male joint and a female joint which are fixedly connected with the end parts of two water-saving electric double-pass sub drill rods respectively, the outer wall of the male joint is in threaded connection with the female joint, and the conductive structure comprises a male joint conductive head which is arranged at the outer end of the male joint and is electrically connected with a cable wire penetrating out of the electric double-pass sub drill rods, and a female joint conductive head which is arranged at the outer end of the female joint and is electrically connected with the cable wire penetrating out of the electric double-pass sub drill rods;

the water through pipelines are coaxially arranged in the hydropower double-pass sub drill rod, and two adjacent water through pipelines are connected through threads, have the same rotation direction as the threads of the male connector and the female connector and have the same screw pitch;

when the male connector and the female connector are in threaded connection, the male connector conductive head can be electrically connected with the female connector conductive head, and two adjacent water communication pipelines can be connected into a whole.

8. The ultrasonic-hydraulic acupoint pressure relief composite fracturing permeation increasing system according to claim 6, wherein the male connector conductive head is a conductive ring which is arranged outside a water pipeline in a surrounding manner and is coaxial with the male connector, and the female connector conductive head is a conductive block which is arranged outside the water pipeline and corresponds to the conductive ring in position;

and/or the inner end of the female joint conductive head is fixedly connected with a conductive rod, the inner end of the conductive rod is electrically connected with a cable, a spring is sleeved outside the conductive rod, and the female joint conductive head and the conductive rod are elastically connected with the female joint through the spring;

and/or all set up the insulator between water passage way outer wall and the water and electricity bi-pass sub drill rod inner wall, between water passage way outer wall and the male joint inner wall, and between water passage way outer wall and the female joint inner wall, the cable conductor inlays and establishes in the insulator, electrically conductive structure establishes on the insulator, and the cable conductor in the water and electricity bi-pass sub drill rod passes insulator and electrically conductive structure electric connection.

9. An application method of an ultrasonic-hydraulic acupoint pressure relief composite fracturing and permeability increasing system based on any one of claims 2-8, comprising the following steps:

selecting a target coal seam, and constructing a borehole in the target coal seam or rock stratum by using a drilling machine;

step two: determining the hole making size and hole making interval, and making a hole making scheme;

step three: connecting an ultrasonic transducer and a hydraulic hole making nozzle with a drill rod, and conveying the drill rod into the bottom of a drilling hole by a drilling machine;

step four: opening a water inlet valve, injecting water into the drill rod through the hole packer, and injecting high-pressure water to the appointed hole making point of the coal seam by a hydraulic hole making nozzle to make the hole;

step five: sealing the hole of the drill hole by using a hole sealer, connecting a cable of an ultrasonic transducer with an ultrasonic generating system, injecting water into the drill hole through the hole sealer and a drill rod, starting water pressure monitoring equipment, and monitoring the water pressure change in the drill hole in real time until the whole drill hole is filled;

step six: after the drill hole is filled with water, an ultrasonic generating system is started, an ultrasonic transducer emits ultrasonic waves, and hydraulic ultrasonic anti-reflection operation is carried out;

step seven: after the hydraulic ultrasonic anti-reflection operation is finished, the ultrasonic generating system is closed, and the ultrasonic operation is stopped;

step eight: after the anti-reflection operation of a section of length in the drilling hole is completed, opening the hole packer, withdrawing a drill rod of a certain length, and circularly operating the steps four to seven until the anti-reflection operation of the last anti-reflection point is finished after the withdrawal;

step nine: and after the anti-reflection is finished, discharging accumulated water in the drill hole, withdrawing the drill rod, and connecting the drill hole into a gas extraction pipeline to perform gas extraction.