CN113216962B - Synergistic anti-reflection desorption promotion experimental system and method for ultrasonic activated fracturing fluid - Google Patents
Synergistic anti-reflection desorption promotion experimental system and method for ultrasonic activated fracturing fluid Download PDFInfo
- Publication number
- CN113216962B CN113216962B CN202110721069.3A CN202110721069A CN113216962B CN 113216962 B CN113216962 B CN 113216962B CN 202110721069 A CN202110721069 A CN 202110721069A CN 113216962 B CN113216962 B CN 113216962B
- Authority
- CN
- China
- Prior art keywords
- ultrasonic
- coal seam
- sodium percarbonate
- water injection
- holes
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000012530 fluid Substances 0.000 title claims abstract description 70
- 238000003795 desorption Methods 0.000 title claims abstract description 46
- 230000002195 synergetic effect Effects 0.000 title claims abstract description 32
- 238000000034 method Methods 0.000 title claims description 12
- 239000003245 coal Substances 0.000 claims abstract description 232
- 238000002347 injection Methods 0.000 claims abstract description 189
- 239000007924 injection Substances 0.000 claims abstract description 189
- 238000005553 drilling Methods 0.000 claims abstract description 146
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 139
- VTIIJXUACCWYHX-UHFFFAOYSA-L disodium;carboxylatooxy carbonate Chemical compound [Na+].[Na+].[O-]C(=O)OOC([O-])=O VTIIJXUACCWYHX-UHFFFAOYSA-L 0.000 claims abstract description 108
- 229940045872 sodium percarbonate Drugs 0.000 claims abstract description 108
- 239000007788 liquid Substances 0.000 claims abstract description 54
- 238000000605 extraction Methods 0.000 claims abstract description 47
- 238000002474 experimental method Methods 0.000 claims abstract description 16
- 238000005336 cracking Methods 0.000 claims abstract description 11
- 230000009471 action Effects 0.000 claims abstract description 10
- 239000007864 aqueous solution Substances 0.000 claims abstract description 7
- 230000001737 promoting effect Effects 0.000 claims abstract description 6
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 32
- 229910052708 sodium Inorganic materials 0.000 claims description 32
- 239000011734 sodium Substances 0.000 claims description 32
- 230000000694 effects Effects 0.000 claims description 21
- 238000007789 sealing Methods 0.000 claims description 16
- 238000011065 in-situ storage Methods 0.000 claims description 14
- 208000010392 Bone Fractures Diseases 0.000 claims description 10
- 206010017076 Fracture Diseases 0.000 claims description 10
- 230000001976 improved effect Effects 0.000 claims description 9
- 230000004913 activation Effects 0.000 claims description 8
- 230000000977 initiatory effect Effects 0.000 claims description 5
- 239000000126 substance Substances 0.000 claims description 5
- 238000002604 ultrasonography Methods 0.000 claims description 5
- 230000003213 activating effect Effects 0.000 claims description 4
- 230000004048 modification Effects 0.000 claims description 4
- 238000012986 modification Methods 0.000 claims description 4
- 238000009434 installation Methods 0.000 claims description 3
- 230000003667 anti-reflective effect Effects 0.000 claims 3
- 230000035699 permeability Effects 0.000 abstract description 17
- 230000001965 increasing effect Effects 0.000 abstract description 12
- 238000005265 energy consumption Methods 0.000 abstract description 3
- 238000005516 engineering process Methods 0.000 description 13
- 150000003254 radicals Chemical class 0.000 description 5
- 239000000243 solution Substances 0.000 description 3
- 230000001133 acceleration Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000001028 reflection method Methods 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- PVGBHEUCHKGFQP-UHFFFAOYSA-N sodium;n-[5-amino-2-(4-aminophenyl)sulfonylphenyl]sulfonylacetamide Chemical compound [Na+].CC(=O)NS(=O)(=O)C1=CC(N)=CC=C1S(=O)(=O)C1=CC=C(N)C=C1 PVGBHEUCHKGFQP-UHFFFAOYSA-N 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C37/00—Other methods or devices for dislodging with or without loading
- E21C37/06—Other methods or devices for dislodging with or without loading by making use of hydraulic or pneumatic pressure in a borehole
- E21C37/12—Other methods or devices for dislodging with or without loading by making use of hydraulic or pneumatic pressure in a borehole by injecting into the borehole a liquid, either initially at high pressure or subsequently subjected to high pressure, e.g. by pulses, by explosive cartridges acting on the liquid
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/006—Production of coal-bed methane
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C39/00—Devices for testing in situ the hardness or other properties of minerals, e.g. for giving information as to the selection of suitable mining tools
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
- E21F17/18—Special adaptations of signalling or alarm devices
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/10—Geothermal energy
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- Geophysics (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Physical Water Treatments (AREA)
- Drilling And Exploitation, And Mining Machines And Methods (AREA)
Abstract
The invention discloses a synergistic permeability-increasing desorption-promoting experimental system of an ultrasonic activated fracturing fluid, which comprises a plurality of coal seam drilling holes arranged in a coal seam, wherein each coal seam drilling hole is internally provided with a water injection branch pipe and an ultrasonic transducer; hole packer is set at the hole of each coal seam drilling hole; the water injection branch pipes in the coal seam drilling holes and the connecting lines of the ultrasonic transducers extend out of the coal seam drilling holes; the water injection branch pipe extends out of the coal seam drilling hole and is connected with a liquid injection main pipe, the liquid injection main pipe is connected with a liquid injection box, and sodium percarbonate aqueous solution for promoting desorption of coal seam gas under the action of ultrasonic waves is contained in the liquid injection box; a liquid injection pump is arranged on the liquid injection main pipe; the connecting line of the ultrasonic transducer is connected with an ultrasonic generator. The invention also discloses a corresponding experimental method. The invention promotes the desorption of coal seam gas while increasing the permeability of the coal seam, greatly improves the volume fraction of the gas to be pumped and the daily extraction pure quantity, shortens the fracturing time, thereby improving the efficiency, and reduces the cracking pressure, thereby reducing the energy consumption, and has good popularization and application values.
Description
Technical Field
The invention relates to a coal seam gas extraction technology, which is particularly suitable for low-permeability high-gas coal seams.
Background
Coal bed gas is also called as coalbed methane, is disaster causing gas for causing coal mine gas disasters, and is also a clean energy source which is endowed in the coal bed and is associated with coal. The pre-gas extraction can reduce the gas content and pressure of the coal bed, and reduce or eliminate the risk of coal and gas outburst. However, about 70% of high-gas outburst coal seams in China have the characteristics of low porosity, poor permeability and high adsorptivity, and simultaneously as the coal seam mining depth is increased, the ground stress is gradually increased, the air permeability of the coal seam is continuously reduced, and the gas desorption is difficult in the extraction process, so that the outburst prevention effect of the area of the technical measure of pre-extraction of gas is poor, and the normal production succession of a mine is further influenced.
In order to improve the gas extraction effect, the desorption and seepage of the coal bed gas are accelerated while the gas permeability of the coal bed is improved. The coal seam permeability increasing technology widely applied at present mainly comprises hydraulic fracturing, high-pressure water jet, microwave excitation and deep hole CO 2 Explosion presplitting and the like, a single coal seam permeability increasing technology is adopted in actual engineering practice, and although the coal seam permeability can be improved to a certain extent, each technology has the use condition and limitation, the coal seam permeability and gas desorption are difficult to simultaneously consider, and the gas extraction lifting effect is limited.
The ultrasonic wave is used as a novel technology for treating the oil layer, has the advantages of no pollution, low energy consumption, quick effect and the like, can enable the fracturing fluid to generate cavitation phenomenon at high temperature and low pressure, and achieves better effect in the aspect of petroleum yield increase through the effects of improving the permeability of the oil rock mass, reducing viscosity, removing scale, removing blockage and the like.
In the field of permeability improvement of low permeability coal seams, because a single ultrasonic technology is difficult to crack coal bodies in a large range, the low permeability coal seam is usually matched with hydraulic fracturing measures.
Because hydraulic fracturing of a coal layer is usually carried out at low temperature (15-25 ℃) and high pressure (25-30 MPa) in actual engineering, in order to fully exert the fracturing and permeability increasing effects of ultrasonic cavitation on coal bodies, the temperature of fracturing fluid is required to be continuously increased, and the engineering energy consumption and difficulty are increased.
Therefore, in order to overcome the defects in the prior art, it is necessary to develop a synergistic anti-reflection method for enhancing gas extraction by modifying coal bodies in situ by using an ultrasonic activated fracturing fluid.
Disclosure of Invention
The invention aims to provide a synergistic permeability-increasing desorption-promoting experimental system for an ultrasonic activated fracturing fluid, which can be used for increasing permeability of a coal bed and simultaneously promoting desorption of gas in the coal bed.
In order to achieve the purpose, the synergistic permeability-increasing desorption-promoting experimental system of the ultrasonic activated fracturing fluid comprises a plurality of coal seam drilling holes arranged in a coal seam, wherein each coal seam drilling hole is internally provided with a water injection branch pipe and an ultrasonic transducer; hole packer is set at the hole of each coal seam drilling hole; the water injection branch pipes in the coal seam drilling holes and the connecting lines of the ultrasonic transducers penetrate through the corresponding hole sealing devices to extend out of the coal seam drilling holes;
the water injection branch pipe extends out of the coal seam drilling hole and is connected with a liquid injection main pipe, the liquid injection main pipe is connected with a liquid injection box, and sodium percarbonate aqueous solution for promoting desorption of coal seam gas under the action of ultrasonic waves is filled in the liquid injection box, wherein the mass concentration of the sodium percarbonate is 0.1-10 per mill; a liquid injection pump is arranged on the liquid injection main pipe; the connecting line of the ultrasonic transducer is connected with an ultrasonic generator positioned outside the coal layer.
And a stop valve is respectively arranged at the part outside the coal seam drilling holes of each water injection branch pipe.
A plurality of non-ultrasonic reference drill holes are also arranged in the coal layer, water injection branch pipes are arranged in the non-ultrasonic reference drill holes, and hole sealing devices are arranged at the hole openings of the non-ultrasonic reference drill holes; the water injection branch pipes in the non-ultrasonic reference holes respectively penetrate through the corresponding hole packer to extend out of the non-ultrasonic reference holes and are connected with the liquid injection main pipe; and the outer part of each water injection branch pipe without the ultrasonic reference drill hole is respectively provided with a stop valve.
The coal seam is also internally provided with a plurality of sodium percarbonate-free reference drill holes, water injection branch pipes are arranged in the sodium percarbonate-free reference drill holes, and hole sealing devices are arranged at the hole openings of the sodium percarbonate-free reference drill holes; the water injection branch pipes in the reference holes without sodium percarbonate respectively penetrate through the corresponding hole packer and extend out of the reference holes without sodium percarbonate; the outer parts of the drill holes of the water injection branch pipes of the reference drill holes without sodium percarbonate are respectively provided with a stop valve, the water injection branch pipes of the reference drill holes without sodium percarbonate are respectively connected with a water injection main pipe, the water injection main pipe is connected with a clear water tank, and a water injection pump is arranged on the water injection main pipe.
The invention also discloses an anti-reflection and desorption promotion experimental method using the ultrasonic activated fracturing fluid synergistic anti-reflection and desorption promotion experimental system, which comprises the following steps in sequence:
step 1 is drilling:
specifically, coal seam drilling holes are constructed on a coal seam 1 in a roadway, the coal seam drilling holes are used as hydraulic fracturing drilling holes and gas extraction drilling holes, and the distance between adjacent coal seam drilling holes is 5-60 meters;
step 2 is a synergistic permeability-increasing desorption-promoting experimental system for installing an ultrasonic activated fracturing fluid:
arranging water injection branch pipes in coal seam drilling holes, wherein each water injection branch pipe is connected with a liquid injection tank through a liquid injection main pipe;
arranging ultrasonic transducers in each coal seam drilling hole, wherein the ultrasonic transducers are connected to an ultrasonic generator through connecting lines; sealing the coal seam drilling holes by using a hole packer;
completing the installation of a synergistic permeability-increasing desorption-promoting experimental system of the ultrasonic activated fracturing fluid at the coal seam;
step 3 is feeding:
specifically, industrial sodium percarbonate is added into a liquid injection box, and the mass concentration of the sodium percarbonate is 0.1 to 10 per mill of hydraulic fracturing liquid after the sodium percarbonate is dissolved in water;
step 4 is low-pressure liquid injection:
the method comprises the steps of opening a stop valve corresponding to each coal seam drilling hole, starting a liquid injection pump, setting the liquid injection pressure to be 4-10 MPa, injecting hydraulic fracturing fluid into each coal seam drilling hole, and allowing the hydraulic fracturing fluid to infiltrate into a coal body through primary cracks of the coal seam under the pressure;
step 5 is the synergistic anti-reflection and desorption promotion of ultrasound and sodium percarbonate:
after the injection pump displays that the injection pressure reaches the preset injection pressure, starting an ultrasonic generator in each coal seam drilling hole, transmitting 35-40 kHz ultrasonic waves into the coal seam drilling holes through an ultrasonic transducer, activating sodium percarbonate in hydraulic fracturing fluid, and enabling high-activity free radicals generated by activation to perform in-situ modification chemical action with the surface of the coal body, so that the gas desorption rate of the coal body is improved, and the mechanical strength of the coal body is reduced;
turning off the ultrasonic generator after each ultrasonic transducer is operated for 30-60 minutes;
step 6 is hydraulic fracturing;
setting the injection pressure of an injection pump to be 35 MPa, carrying out hydraulic fracturing, and enabling the activated hydraulic fracturing fluid to further infiltrate into the deep part of a coal seam at a coal seam drilling position under high pressure, so as to modify more coal bodies in situ; recording the cracking pressure of the coal seam and the time for fracturing;
step 7, finishing the anti-reflection desorption promotion operation:
specifically, when the pressure of the liquid injection pump is continuously lower than 18MPa for 3 minutes, the fracturing is finished, the collaborative anti-reflection and desorption promotion experimental system of the ultrasonic activated fracturing liquid is removed, the hydraulic fracturing liquid is returned, the fracturing extraction holes are connected into a gas extraction system to carry out gas extraction, and the concentration of the extracted gas of each drilling hole and the extraction scalar information are monitored and recorded through the gas extraction system.
Simultaneously carrying out an ultrasonic-free comparison experiment and a sodium percarbonate-free comparison experiment, specifically comprising the following steps:
the coal seam is also internally provided with a plurality of ultrasonic reference-free drilling holes and a plurality of sodium percarbonate reference-free drilling holes, water injection branch pipes are arranged in the ultrasonic reference-free drilling holes, and hole sealing devices are arranged at the hole openings of the ultrasonic reference-free drilling holes; the water injection branch pipes in the non-ultrasonic reference drilling holes respectively penetrate through the corresponding hole packer to extend out of the non-ultrasonic reference drilling holes; the outer part of each water injection branch pipe without the ultrasonic reference drill hole is respectively provided with a stop valve;
the coal seam is also internally provided with a plurality of sodium percarbonate-free reference drill holes, water injection branch pipes are arranged in the sodium percarbonate-free reference drill holes, and hole sealing devices are arranged at the hole openings of the sodium percarbonate-free reference drill holes; the water injection branch pipes in the reference holes without sodium percarbonate respectively penetrate through the corresponding hole packer and extend out of the reference holes without sodium percarbonate; the outer parts of the drill holes of the water injection branch pipes of the reference drill holes without sodium percarbonate are respectively provided with a stop valve, the water injection branch pipes of the reference drill holes without sodium percarbonate are respectively connected with a water injection main pipe, the water injection main pipe is connected with a clear water tank, and a water injection pump is arranged on the water injection main pipe;
in the step 1, when a coal seam is drilled in a roadway towards the coal seam, an ultrasonic reference-free drill hole and a sodium percarbonate reference-free drill hole are simultaneously constructed, and the ultrasonic reference-free drill hole and the sodium percarbonate reference-free drill hole are used as hydraulic fracturing drill holes and gas extraction drill holes;
the coal seam drilling holes and the ultrasonic reference-free drilling holes and the sodium percarbonate reference-free drilling holes are collectively called as fracturing extraction holes, and the distance between adjacent fracturing extraction holes is 5-60 meters;
in the step 2, water injection branch pipes are arranged in each ultrasonic reference-free drilling hole and each sodium percarbonate-free reference drilling hole, the water injection branch pipes of the ultrasonic reference-free drilling holes are connected with a water injection tank through a water injection main pipe, and the water injection branch pipes of the sodium percarbonate-free reference drilling holes are connected with the water injection tank through the water injection main pipe;
arranging an ultrasonic transducer in the reference borehole without sodium percarbonate, wherein the ultrasonic transducer is connected to an ultrasonic generator through a connecting line;
sealing the reference drilling hole without ultrasonic and the reference drilling hole without sodium percarbonate by using a hole packer;
in the step 3, adding water into a water injection tank as hydraulic fracturing fluid without sodium percarbonate;
in the step 4, the stop valves corresponding to the reference drilling holes without ultrasonic and the reference drilling holes without sodium percarbonate are opened, the water injection pump is started while the water injection pump is started, the water injection pressure is set to be 4-10 MPa, the water injection pump injects hydraulic fracturing fluid containing sodium percarbonate into the reference drilling holes without ultrasonic, and the water injection pump injects hydraulic fracturing fluid without sodium percarbonate into the reference drilling holes without sodium percarbonate;
the hydraulic fracturing fluid seeps into the coal body through the primary fracture of the coal bed under the pressure of 4-10 MPa;
in the step 5, starting an ultrasonic generator at each reference drilling hole without sodium percarbonate, and enabling an ultrasonic transducer in the reference drilling hole without sodium percarbonate to also emit ultrasonic waves of 35-40 kHz, wherein the ultrasonic waves and the hydraulic fracturing fluid without sodium percarbonate act on a coal body simultaneously;
in step 6, for each ultrasound-free reference borehole: the hydraulic fracturing fluid is further permeated to the deep part of the coal seam at the position without the ultrasonic reference drill hole under high pressure, and the coal body where the seepage is performed is modified in situ;
for each sodium percarbonate free reference borehole: setting the water injection pressure of a water injection pump to be 35 MPa, carrying out hydraulic fracturing, and enabling hydraulic fracturing fluid to further infiltrate to the deep part of the coal seam at the reference drilling position without sodium percarbonate under high pressure;
in the step 7, for each ultrasonic reference-free borehole, the parameter characteristic indicating the end of fracturing is that the pressure of the injection pump is lower than 18MPa for 3 minutes continuously;
for each reference borehole without sodium percarbonate, the parameter characteristic indicating the end of fracturing is that the pressure of the water injection pump is lower than 18MPa for 3 minutes continuously.
Recording the coal seam cracking pressure and the fracturing time of each non-ultrasonic reference drill hole; the fracture initiation pressure and time to fracture of the coal seam at each reference borehole without sodium percarbonate were recorded.
The invention has the following advantages:
sodium percarbonate is an efficient and environment-friendly medicament, can be used for in-situ restoration of polluted sites after activation, and has high use safety, wide action range and no secondary pollution. The invention uses the sodium percarbonate solution activated by ultrasound to regulate the surface polarity of the coal body and reduce the physical strength of the coal body; sodium percarbonate is introduced into hydraulic fracturing fluid, and is activated by adopting an ultrasonic technology, so that the surface polarity of the coal body can be regulated and controlled to accelerate the desorption of coal seam gas, and meanwhile, the physical strength of the coal body is reduced, and the cracking of the coal body and the expansion and extension of cracks are promoted.
The essence of the technology is different from the prior permeability-increasing technology in that the technology not only carries out permeability increase of the coal bed, but also accelerates desorption of the gas in the coal bed, is a technology integrating the desorption acceleration and the permeability increase, can extract more gas from the coal bed, further reduces the risk of outburst accidents of the coal and the gas, and improves the recycling rate of the gas. In the prior technical scheme of coal seam permeability improvement, the desorption rate of coal seam gas is not improved, only coal seam cracks are simply expanded or extended, the gas can flow out along the cracks conveniently, and the desorption promotion effect is not achieved.
The synergistic permeability-increasing desorption-promoting experimental system of the ultrasonic activated fracturing fluid is simple in structure and convenient for permeability-increasing desorption-promoting operation. And due to the arrangement of each stop valve, partial coal seam drilling can be conveniently enhanced according to actual conditions. Particularly, when the anti-reflection desorption promotion operation is carried out on a plurality of coal seam drilling holes at the same time, the completion time of each coal seam drilling hole is asynchronous, and the stop valve can be arranged to close one corresponding stop valve when one coal seam drilling hole is arranged.
The ultrasonic transducer is not arranged in the ultrasonic reference-free borehole, so that the anti-reflection and desorption promotion effects without the synergistic effect of ultrasonic waves can be compared conveniently. In the invention, as the ultrasonic wave can activate sodium percarbonate, the high-activity free radical generated by the activation has a chemical action with the surface of the coal body, the surface polarity of the coal body is changed, and the physical strength of the coal body is reduced, so that the anti-reflection and desorption promotion effects under the synergistic action of the ultrasonic wave and the sodium percarbonate aqueous solution are far stronger than those under the non-synergistic action.
The sodium percarbonate-free reference drill hole is filled with water instead of sodium percarbonate aqueous solution, so that the anti-reflection and desorption promotion effects without the synergistic effect of sodium percarbonate can be compared conveniently.
The anti-reflection and desorption-promoting experimental method is convenient to implement, and the method can be directly applied to coal seam exploitation practice after the ultrasonic-free comparison experiment and the sodium percarbonate-free comparison experiment in claim 6 are removed (the technical scheme in claim 5), and can be directly used as an actual anti-reflection and desorption-promoting method for a coal seam, so that coal seam gas desorption is promoted while coal seam anti-reflection, the volume fraction of gas drainage is greatly improved, daily extraction scalar is greatly improved, fracturing time is shortened, the time efficiency of gas extraction is improved, the cracking pressure is reduced, the electric energy consumed by a pump in hydraulic fracturing operation is reduced, and the method has the remarkable technical effects of saving energy and reducing consumption, improving the time efficiency of gas extraction, improving the gas extraction quantity and the like and has good popularization and application values.
Drawings
Fig. 1 is a schematic structural view of the present invention.
Detailed Description
As shown in fig. 1, the experimental system for synergistic permeability-increasing desorption-promoting of the ultrasonic activated fracturing fluid comprises a plurality of coal seam drilling holes 1 arranged in a coal seam 3, wherein each coal seam drilling hole 1 is internally provided with a water injection branch pipe 2 and an ultrasonic transducer 4; hole packer 5 is arranged at the hole opening of each coal seam drilling hole 1; the water injection branch pipes 2 in the coal seam drilling holes 1 and the connecting lines of the ultrasonic transducers 4 penetrate through the corresponding hole sealers 5 and extend out of the coal seam drilling holes 1;
the water injection branch pipe 2 extends out of the coal seam drilling hole 1 and is connected with a liquid injection main pipe 6, the liquid injection main pipe 6 is connected with a liquid injection box 7, sodium percarbonate aqueous solution for promoting the desorption of the gas of the coal seam 3 under the action of ultrasonic waves is filled in the liquid injection box 7, and the mass concentration of the sodium percarbonate is 0.1-10 mill (including two end values); a liquid injection pump 8 is arranged on the liquid injection main pipe 6; the ultrasonic generator 9 positioned outside the coal seam 3 is connected with the connecting line of the ultrasonic transducer 4. The connection line of the ultrasonic transducer 4 is preferably a pressure-resistant waterproof cable. The synergistic permeability-increasing desorption-promoting experimental system of the ultrasonic activated fracturing fluid is simple in structure and convenient for permeability-increasing desorption-promoting operation.
The part outside the coal seam drilling holes 1 of each water injection branch pipe 2 is respectively provided with a stop valve 11. The arrangement of each stop valve 11 is convenient for carrying out anti-reflection on part of the coal seam drilling holes 1 according to actual conditions. Particularly, when the anti-reflection and desorption promotion operations are performed on a plurality of coal seam drilling holes 1 at the same time, the completion time of each coal seam drilling hole 1 is asynchronous, and the stop valve 11 can be arranged to close one corresponding stop valve 11 when one coal seam drilling hole 1 is completed.
The coal seam 3 is also internally provided with a plurality of non-ultrasonic reference drill holes 10, water injection branch pipes 2 are arranged in the non-ultrasonic reference drill holes 10, and hole packer 5 is arranged at the hole openings of each non-ultrasonic reference drill hole 10; the water injection branch pipes 2 in the non-ultrasonic reference drilling holes 10 respectively penetrate through the corresponding hole packer 5 to extend out of the non-ultrasonic reference drilling holes 10 and are connected with the liquid injection main pipe 6; the outer part of the water injection branch pipe 2 of each non-ultrasonic reference drill hole 10 is respectively provided with a stop valve 11.
The ultrasonic transducer 4 is not arranged in the ultrasonic reference-free drill hole 10, so that the anti-reflection and desorption promotion effects without the synergistic effect of ultrasonic waves can be compared conveniently. In the invention, as the ultrasonic wave can activate sodium percarbonate, the high-activity free radical generated by the activation has a chemical action with the surface of the coal body, the surface polarity of the coal body is changed, and the physical strength of the coal body is reduced, so that the anti-reflection and desorption promotion effects under the synergistic action of the ultrasonic wave and the sodium percarbonate aqueous solution are far stronger than those under the non-synergistic action.
The coal seam 3 is also internally provided with a plurality of sodium percarbonate-free reference drill holes 12, the sodium percarbonate-free reference drill holes 12 are internally provided with water injection branch pipes 2, and the hole openings of the sodium percarbonate-free reference drill holes 12 are respectively provided with a hole packer 5; the water injection branch pipes 2 in the reference drilling holes 12 without sodium percarbonate respectively penetrate through the corresponding hole packer 5 to extend out of the reference drilling holes 12 without sodium percarbonate; the outer part of the water injection branch pipe 2 of each sodium percarbonate free reference drill hole 12 is respectively provided with a stop valve 11, the water injection branch pipe 2 of each sodium percarbonate free reference drill hole 12 is respectively connected with a water injection main pipe 13, the water injection main pipe 13 is connected with a clear water tank 14, and the water injection main pipe 13 is provided with a water injection pump 15.
The absence of sodium percarbonate reference borehole 12 is not filled with aqueous sodium percarbonate but water, which facilitates comparison of the anti-reflection and desorption promoting effects without synergistic effect of sodium percarbonate.
The invention also discloses an anti-reflection and desorption promotion experimental method using the ultrasonic activated fracturing fluid synergistic anti-reflection and desorption promotion experimental system, which comprises the following steps in sequence:
step 1 is drilling:
specifically, coal seam drilling holes 1 are constructed on a coal seam 3 in a roadway, the coal seam drilling holes 1 are used as hydraulic fracturing drilling holes and gas extraction drilling holes, and the distance between adjacent coal seam drilling holes 1 is 5-60 meters (including two end values);
step 2 is a synergistic permeability-increasing desorption-promoting experimental system for installing an ultrasonic activated fracturing fluid:
specifically, water injection branch pipes 2 are arranged in each coal seam drilling hole 1, and each water injection branch pipe 2 is connected with a liquid injection box 7 through a liquid injection main pipe 6;
an ultrasonic transducer 4 is arranged in each coal seam borehole 1, where the ultrasonic transducer 4 is connected to an ultrasonic generator 9 by a connecting line; sealing the coal seam drilling holes 1 by using a hole packer 5; the installation of a synergistic permeability-increasing desorption-promoting experimental system of the ultrasonic activated fracturing fluid is completed at the coal seam 3;
step 3 is feeding:
specifically, industrial sodium percarbonate is added into a liquid injection box 7, and the mass concentration of the sodium percarbonate is 0.1 to 10 per mill of hydraulic fracturing liquid after the sodium percarbonate is dissolved in water;
step 4 is low-pressure liquid injection:
specifically, a stop valve 11 corresponding to each coal seam drilling hole 1 is opened, a liquid injection pump 8 is started, the liquid injection pressure is set to be 4-10 MPa (including two end values), hydraulic fracturing fluid is injected into each coal seam drilling hole 1, and the hydraulic fracturing fluid seeps into a coal body through primary cracks of a coal seam 3 under the pressure;
step 5 is the synergistic anti-reflection and desorption promotion of ultrasound and sodium percarbonate:
specifically, after the injection pump 8 displays that the injection pressure reaches the preset injection pressure, an ultrasonic transducer 4 in each coal seam drilling hole 1 is started, 35-40 kHz ultrasonic waves are emitted into the coal seam drilling holes 1 through the ultrasonic transducer 4, sodium percarbonate in hydraulic fracturing fluid is activated, high-activity free radicals generated by activation and the surface of the coal body generate in-situ modification chemical action, so that the gas desorption rate of the coal body is improved, and the mechanical strength of the coal body is reduced;
after each ultrasonic transducer 4 is operated for 30-60 minutes (including two end values), the ultrasonic generator 9 is turned off so as to turn off each ultrasonic transducer 4;
step 6 is hydraulic fracturing;
the initiation pressure of the hydraulic fracturing of the coal seam 3 is 25-30 MPa, the injection pressure of the injection pump 8 is set to be 35 MPa for the sake of stability, the hydraulic fracturing is carried out, the activated hydraulic fracturing fluid further infiltrates into the deep part of the coal seam 3 at the position of the coal seam drilling hole 1 under high pressure, and more coal bodies are modified in situ on the basis of the step 5; recording the cracking pressure of the coal seam and the time for fracturing;
step 7, finishing the anti-reflection desorption promotion operation:
specifically, when the pressure of the injection pump 8 is continuously lower than 18MPa for 3 minutes, the completion of fracturing is indicated, the collaborative permeability-increasing desorption-promoting experimental system of the ultrasonic activated fracturing fluid is dismantled, the hydraulic fracturing fluid is returned, the fracturing extraction holes are connected into the gas extraction system to carry out gas extraction, and the concentration of extracted gas of each drilling hole and the extraction scalar information are monitored and recorded through the gas extraction system.
The gas extraction system is provided with a gas detector and other devices, and is preferably provided with a CGWZ-100 (A) -Z type pipeline gas comprehensive parameter tester manufactured by optical technology Co., ltd. Monitoring and recording the concentration of the extracted gas and the extraction scalar information of each borehole by the gas extraction system is a conventional technology, and the gas extraction system is not described in detail.
In the process of the anti-reflection desorption acceleration experimental method, ultrasound-free comparison experiments and sodium percarbonate-free comparison experiments are carried out simultaneously, and the method specifically comprises the following steps:
in the step 1, when a coal seam drilling hole 1 is constructed towards a coal seam 3 in a roadway, an ultrasonic-free reference drilling hole 10 and a sodium percarbonate-free reference drilling hole 12 are constructed simultaneously, and the ultrasonic-free reference drilling hole 10 and the sodium percarbonate-free reference drilling hole 12 are used as hydraulic fracturing drilling holes and gas extraction drilling holes;
the coal seam drilling hole 1, the ultrasonic reference-free drilling hole 10 and the sodium percarbonate-free reference drilling hole 12 are collectively called as fracturing extraction holes, and the distance between adjacent fracturing extraction holes is 5-60 meters (including two end values);
in the step 2, water injection branch pipes 2 are arranged in each ultrasonic reference-free drilling hole 10 and each sodium percarbonate-free reference drilling hole 12, the water injection branch pipes 2 of the ultrasonic reference-free drilling holes 10 are connected with a water injection tank 7 through a water injection main pipe 6, and the water injection branch pipes 2 of the sodium percarbonate-free reference drilling holes 12 are connected with a water injection tank 14 through a water injection main pipe 13;
an ultrasonic transducer 4 is arranged in the reference borehole 12 without sodium percarbonate, where the ultrasonic transducer 4 is connected to an ultrasonic generator 9 by means of a connection line;
sealing the reference drill hole 10 without ultrasound and the reference drill hole 12 without sodium percarbonate by using a hole packer 5;
in step 3, water is added into the water injection tank 14 as hydraulic fracturing fluid without sodium percarbonate;
in the step 4, the stop valves 11 corresponding to the ultrasonic reference-free drilling holes 10 and the sodium percarbonate-free reference drilling holes 12 are opened, the water injection pump 15 is started, the water injection pressure is set to be 4-10 MPa (including two end values), the water injection pump 8 injects hydraulic fracturing fluid containing sodium percarbonate into the ultrasonic reference-free drilling holes 10, and the water injection pump 15 injects hydraulic fracturing fluid containing no sodium percarbonate into the sodium percarbonate-free reference drilling holes 12;
the hydraulic fracturing fluid seeps into the coal body through the primary fracture of the coal bed 3 under the pressure of 4-10 MPa;
in the step 5, starting an ultrasonic generator 9 at each sodium percarbonate free reference drill hole 12, and enabling an ultrasonic transducer 4 in each sodium percarbonate free reference drill hole 12 to also emit ultrasonic waves of 35-40 kHz, wherein the ultrasonic waves and the hydraulic fracturing fluid without sodium percarbonate act on a coal body simultaneously; providing conditions for obtaining contrast data;
in step 6, for each ultrasound-free reference borehole 10: the hydraulic fracturing is carried out under the condition that the hydraulic fracturing fluid is further permeated to the deep part of the coal bed 3 at the position of the non-ultrasonic reference drill hole 10 under high pressure, and the coal body where the seepage is carried out is modified in situ;
for each sodium percarbonate free reference borehole 12: setting the water injection pressure of the water injection pump 15 to be 35 MPa, carrying out hydraulic fracturing, and enabling the hydraulic fracturing fluid to further infiltrate to the deep part of the coal seam 3 at the sodium percarbonate-free reference drill hole 12 under high pressure;
in the step 7, for each ultrasonic reference-free borehole 10, the parameter characteristic indicating the end of fracturing is that the pressure of the injection pump 8 is lower than 18MPa for 3 minutes continuously;
for each reference borehole without sodium percarbonate, the parameter characteristic indicating the end of fracturing is that the pressure of the water injection pump 15 is lower than 18MPa for 3 minutes in succession.
Recording the coal seam fracture initiation pressure and the time for fracturing at each non-ultrasonic reference borehole 10; the fracture initiation pressure and time to fracture of the coal seam at each reference borehole 12 without sodium percarbonate was recorded.
Table 1, borehole fracturing parameters and gas drainage records:
as can be seen from the data in Table 1, the in-situ modified coal enhanced gas extraction method of the ultrasonic activated fracturing fluid of the invention can reduce the cracking pressure of a coal bed by about 5MPa compared with the method without using ultrasonic waves and only using sodium percarbonate solution, reduce the time for fracturing by about 20 minutes, and increase the volume fraction of the extracted gas by more than 21 percent (more times) and increase the daily gas extraction pure quantity by about 3 times.
As can be seen from the data in Table 1, the in-situ modified coal enhanced gas extraction method of the ultrasonic activated fracturing fluid has the advantages that compared with the method adopting ultrasonic wave and hydraulic fracturing but not adopting sodium percarbonate solution, the cracking pressure of a coal bed can be reduced by about 4MPa, the time for fracturing is reduced by about 20 minutes, the volume fraction lifting amount of extracted gas is more than 18 percent (at least doubled), and the daily gas extraction pure amount is increased to 2-4 times.
The invention can obviously reduce the risk of coal and gas outburst, improve the gas drainage efficiency and save the production cost, has great progress compared with the existing hydraulic fracturing reinforced coal seam gas drainage technology, and has wide practicability in the technical field.
Analysis considered that: the technology of the patent activates sodium percarbonate in the hydraulic fracturing fluid to generate high-activity free radicals through ultrasonic waves, carries out in-situ modification on the surface of the coal bed, and accelerates desorption of coal bed gas through regulating and controlling the polarity of the surface of the coal; the surface of the coal bed is modified to be favorable for absorbing and activating the fracturing fluid by the coal body, the ultrasonic activation of sodium percarbonate enables the fracturing fluid to be alkaline (pH=10-11), the mechanical strength of the coal is obviously reduced after the ultrasonic activation of sodium percarbonate acts on the coal bed, the cracking pressure of the coal bed is reduced, and the coal penetrating length of a crack is increased; ultrasonic waves generate a local thermal effect at a coal-water interface, thermal stress of the coal promotes crack expansion and extension, and the fracturing fluid is promoted to further infiltrate into the deep part of the coal bed, so that a net-shaped crack is formed in cooperation with hydraulic fracturing, and seepage and migration of coal bed gas are facilitated.
The applicant also makes control experiments on the contact angle of the coal surface and the physical properties of the coal after being wetted by different fracturing fluids for the same coal sample, and the results are shown in table 2:
table 2, coal surface contact angle and coal physical properties of coal samples after being wetted by different fracturing fluids:
as can be seen from table 2, the use of ultrasonic waves (+clear water) alone or industrial sodium percarbonate alone only had a slight effect on the coal surface polarity and the coal mechanical strength, whereas the use of an ultrasonically activated sodium percarbonate fracturing fluid significantly increased the coal surface polarity (contact angle reduced by more than 27% compared to no treatment), significantly reduced the coal mechanical strength (reduced by more than 39.8% compared to no treatment).
Claims (6)
1. Ultrasonic activated fracturing fluid's collaborative anti-reflection promotes desorption experimental system, including setting up a plurality of coal seam drilling in the coal seam, its characterized in that: water injection branch pipes and ultrasonic transducers are arranged in the coal seam drilling holes; hole packer is set at the hole of each coal seam drilling hole; the water injection branch pipes in the coal seam drilling holes and the connecting lines of the ultrasonic transducers penetrate through the corresponding hole sealing devices to extend out of the coal seam drilling holes;
the water injection branch pipe extends out of the coal seam drilling hole and is connected with a liquid injection main pipe, the liquid injection main pipe is connected with a liquid injection box, and sodium percarbonate aqueous solution for promoting desorption of coal seam gas under the action of ultrasonic waves is filled in the liquid injection box, wherein the mass concentration of the sodium percarbonate is 0.1-10 per mill; a liquid injection pump is arranged on the liquid injection main pipe; the connecting circuit of the ultrasonic transducer is connected with an ultrasonic generator positioned outside the coal layer;
the ultrasonic transducer is used for transmitting ultrasonic waves of 35-40 kHz into the coal seam drilling hole (1) and activating sodium percarbonate in the hydraulic fracturing fluid.
2. The synergistic antireflective desorption-promoting experimental system of an ultrasonically activated fracturing fluid of claim 1, wherein: and a stop valve is respectively arranged at the part outside the coal seam drilling holes of each water injection branch pipe.
3. The synergistic antireflective desorption-promoting experimental system of an ultrasonically activated fracturing fluid according to claim 1 or 2, wherein: a plurality of non-ultrasonic reference drill holes are also arranged in the coal layer, water injection branch pipes are arranged in the non-ultrasonic reference drill holes, and hole sealing devices are arranged at the hole openings of the non-ultrasonic reference drill holes; the water injection branch pipes in the non-ultrasonic reference holes respectively penetrate through the corresponding hole packer to extend out of the non-ultrasonic reference holes and are connected with the liquid injection main pipe; and the outer part of each water injection branch pipe without the ultrasonic reference drill hole is respectively provided with a stop valve.
4. The synergistic antireflective desorption-promoting experimental system of an ultrasonically activated fracturing fluid of claim 3, wherein: the coal seam is also internally provided with a plurality of sodium percarbonate-free reference drill holes, water injection branch pipes are arranged in the sodium percarbonate-free reference drill holes, and hole sealing devices are arranged at the hole openings of the sodium percarbonate-free reference drill holes; the water injection branch pipes in the reference holes without sodium percarbonate respectively penetrate through the corresponding hole packer and extend out of the reference holes without sodium percarbonate; the outer parts of the drill holes of the water injection branch pipes of the reference drill holes without sodium percarbonate are respectively provided with a stop valve, the water injection branch pipes of the reference drill holes without sodium percarbonate are respectively connected with a water injection main pipe, the water injection main pipe is connected with a clear water tank, and a water injection pump is arranged on the water injection main pipe.
5. An anti-reflection and desorption promotion experimental method using the synergistic anti-reflection and desorption promotion experimental system of the ultrasonic activated fracturing fluid, which is characterized by comprising the following steps in sequence:
step 1 is drilling:
specifically, coal seam drilling holes (1) are constructed in a roadway towards a coal seam, the coal seam drilling holes are used as hydraulic fracturing drilling holes and gas extraction drilling holes, and the distance between adjacent coal seam drilling holes is 5-60 meters;
step 2 is a synergistic permeability-increasing desorption-promoting experimental system for installing an ultrasonic activated fracturing fluid:
arranging water injection branch pipes in coal seam drilling holes, wherein each water injection branch pipe is connected with a liquid injection tank through a liquid injection main pipe;
arranging ultrasonic transducers in each coal seam drilling hole, wherein the ultrasonic transducers are connected to an ultrasonic generator through connecting lines; sealing the coal seam drilling holes by using a hole packer;
completing the installation of a synergistic permeability-increasing desorption-promoting experimental system of the ultrasonic activated fracturing fluid at the coal seam;
step 3 is feeding:
specifically, industrial sodium percarbonate is added into a liquid injection box, and the mass concentration of the sodium percarbonate is 0.1 to 10 per mill of hydraulic fracturing liquid after the sodium percarbonate is dissolved in water;
step 4 is low-pressure liquid injection:
the method comprises the steps of opening a stop valve corresponding to each coal seam drilling hole, starting a liquid injection pump, setting the liquid injection pressure to be 4-10 MPa, injecting hydraulic fracturing fluid into each coal seam drilling hole, and allowing the hydraulic fracturing fluid to infiltrate into a coal body through primary cracks of the coal seam under the pressure;
step 5 is the synergistic anti-reflection and desorption promotion of ultrasound and sodium percarbonate:
after the injection pump displays that the injection pressure reaches the preset injection pressure, starting an ultrasonic generator in each coal seam drilling hole, transmitting 35-40 kHz ultrasonic waves into the coal seam drilling holes through an ultrasonic transducer, activating sodium percarbonate in hydraulic fracturing fluid, and enabling high-activity free radicals generated by activation to perform in-situ modification chemical action with the surface of the coal body, so that the gas desorption rate of the coal body is improved, and the mechanical strength of the coal body is reduced;
turning off the ultrasonic generator after each ultrasonic transducer is operated for 30-60 minutes;
step 6 is hydraulic fracturing;
setting the injection pressure of an injection pump to be 35 MPa, carrying out hydraulic fracturing, and enabling the activated hydraulic fracturing fluid to further infiltrate into the deep part of a coal seam at a coal seam drilling position under high pressure, so as to modify more coal bodies in situ; recording the cracking pressure of the coal seam and the time for fracturing;
step 7, finishing the anti-reflection desorption promotion operation:
specifically, when the pressure of the liquid injection pump is continuously lower than 18MPa for 3 minutes, the fracturing is finished, the collaborative anti-reflection and desorption promotion experimental system of the ultrasonic activated fracturing liquid is removed, the hydraulic fracturing liquid is returned, the fracturing extraction holes are connected into a gas extraction system to carry out gas extraction, and the concentration of the extracted gas of each drilling hole and the extraction scalar information are monitored and recorded through the gas extraction system.
6. The method for anti-reflection desorption promotion experiment according to claim 5, wherein:
simultaneously carrying out an ultrasonic-free comparison experiment and a sodium percarbonate-free comparison experiment, specifically comprising the following steps:
the coal seam is also internally provided with a plurality of ultrasonic reference-free drilling holes and a plurality of sodium percarbonate reference-free drilling holes, water injection branch pipes are arranged in the ultrasonic reference-free drilling holes, and hole sealing devices are arranged at the hole openings of the ultrasonic reference-free drilling holes; the water injection branch pipes in the non-ultrasonic reference drilling holes respectively penetrate through the corresponding hole packer to extend out of the non-ultrasonic reference drilling holes; the outer part of each water injection branch pipe without the ultrasonic reference drill hole is respectively provided with a stop valve;
the coal seam is also internally provided with a plurality of sodium percarbonate-free reference drill holes, water injection branch pipes are arranged in the sodium percarbonate-free reference drill holes, and hole sealing devices are arranged at the hole openings of the sodium percarbonate-free reference drill holes; the water injection branch pipes in the reference holes without sodium percarbonate respectively penetrate through the corresponding hole packer and extend out of the reference holes without sodium percarbonate; the outer parts of the drill holes of the water injection branch pipes of the reference drill holes without sodium percarbonate are respectively provided with a stop valve, the water injection branch pipes of the reference drill holes without sodium percarbonate are respectively connected with a water injection main pipe, the water injection main pipe is connected with a clear water tank, and a water injection pump is arranged on the water injection main pipe;
in the step 1, when a coal seam is drilled in a roadway towards the coal seam, an ultrasonic reference-free drill hole and a sodium percarbonate reference-free drill hole are simultaneously constructed, and the ultrasonic reference-free drill hole and the sodium percarbonate reference-free drill hole are used as hydraulic fracturing drill holes and gas extraction drill holes;
the coal seam drilling holes and the ultrasonic reference-free drilling holes and the sodium percarbonate reference-free drilling holes are collectively called as fracturing extraction holes, and the distance between adjacent fracturing extraction holes is 5-60 meters;
in the step 2, water injection branch pipes are arranged in each ultrasonic reference-free drilling hole and each sodium percarbonate-free reference drilling hole, the water injection branch pipes of the ultrasonic reference-free drilling holes are connected with a water injection tank through a water injection main pipe, and the water injection branch pipes of the sodium percarbonate-free reference drilling holes are connected with the water injection tank through the water injection main pipe;
arranging an ultrasonic transducer in the reference borehole without sodium percarbonate, wherein the ultrasonic transducer is connected to an ultrasonic generator through a connecting line;
sealing the reference drilling hole without ultrasonic and the reference drilling hole without sodium percarbonate by using a hole packer;
in the step 3, adding water into a water injection tank as hydraulic fracturing fluid without sodium percarbonate;
in the step 4, the stop valves corresponding to the reference drilling holes without ultrasonic and the reference drilling holes without sodium percarbonate are opened, the water injection pump is started while the water injection pump is started, the water injection pressure is set to be 4-10 MPa, the water injection pump injects hydraulic fracturing fluid containing sodium percarbonate into the reference drilling holes without ultrasonic, and the water injection pump injects hydraulic fracturing fluid without sodium percarbonate into the reference drilling holes without sodium percarbonate;
the hydraulic fracturing fluid seeps into the coal body through the primary fracture of the coal bed under the pressure of 4-10 MPa;
in the step 5, starting an ultrasonic generator at each reference drilling hole without sodium percarbonate, and enabling an ultrasonic transducer in the reference drilling hole without sodium percarbonate to also emit ultrasonic waves of 35-40 kHz, wherein the ultrasonic waves and the hydraulic fracturing fluid without sodium percarbonate act on a coal body simultaneously;
in step 6, for each ultrasound-free reference borehole: the hydraulic fracturing fluid is further permeated to the deep part of the coal seam at the position without the ultrasonic reference drill hole under high pressure, and the coal body where the seepage is performed is modified in situ;
for each sodium percarbonate free reference borehole: setting the water injection pressure of a water injection pump to be 35 MPa, carrying out hydraulic fracturing, and enabling hydraulic fracturing fluid to further infiltrate to the deep part of the coal seam at the reference drilling position without sodium percarbonate under high pressure;
in the step 7, for each ultrasonic reference-free borehole, the parameter characteristic indicating the end of fracturing is that the pressure of the injection pump is lower than 18MPa for 3 minutes continuously;
for each reference borehole without sodium percarbonate, the parameter characteristic indicating the end of fracturing is that the pressure of the water injection pump is lower than 18MPa for 3 minutes continuously;
recording the coal seam cracking pressure and the fracturing time of each non-ultrasonic reference drill hole; the fracture initiation pressure and time to fracture of the coal seam at each reference borehole without sodium percarbonate were recorded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110721069.3A CN113216962B (en) | 2021-06-28 | 2021-06-28 | Synergistic anti-reflection desorption promotion experimental system and method for ultrasonic activated fracturing fluid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110721069.3A CN113216962B (en) | 2021-06-28 | 2021-06-28 | Synergistic anti-reflection desorption promotion experimental system and method for ultrasonic activated fracturing fluid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113216962A CN113216962A (en) | 2021-08-06 |
| CN113216962B true CN113216962B (en) | 2023-11-17 |
Family
ID=77080998
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110721069.3A Active CN113216962B (en) | 2021-06-28 | 2021-06-28 | Synergistic anti-reflection desorption promotion experimental system and method for ultrasonic activated fracturing fluid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113216962B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114737938A (en) * | 2022-03-21 | 2022-07-12 | 重庆大学 | Coal seam ultrasonic activation staged fracturing device |
| CN115012893B (en) * | 2022-05-31 | 2024-04-16 | 贵州大学 | Ultrasonic wave cooperated hydraulic fracturing device for increasing yield of coalbed methane |
| CN116177637A (en) * | 2023-02-20 | 2023-05-30 | 长安大学 | Repairing system and method for ultrasonic-assisted reinforced underground water circulating well |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3934649A (en) * | 1974-07-25 | 1976-01-27 | The United States Of America As Represented By The United States Energy Research And Development Administration | Method for removal of methane from coalbeds |
| CN1221849A (en) * | 1997-09-22 | 1999-07-07 | 瓦斯塔资源有限公司 | Chemically induced stimulation of cleat formation in subterranean coal formation |
| CN107762549A (en) * | 2017-10-13 | 2018-03-06 | 临沂矿业集团有限责任公司 | The rock body quality of mine drilling anti-reflection formula gas pumping assay method in multistage interval |
| CN108868702A (en) * | 2018-06-21 | 2018-11-23 | 河南理工大学 | A kind of coal bed gas ultrasonic wave desorption extraction water discharge method |
| CN212003131U (en) * | 2020-03-31 | 2020-11-24 | 石家庄铁道大学 | Enhanced gas extraction system applying hot steam and microwave radiation in cooperation with permeability-increasing coal seam |
-
2021
- 2021-06-28 CN CN202110721069.3A patent/CN113216962B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3934649A (en) * | 1974-07-25 | 1976-01-27 | The United States Of America As Represented By The United States Energy Research And Development Administration | Method for removal of methane from coalbeds |
| CN1221849A (en) * | 1997-09-22 | 1999-07-07 | 瓦斯塔资源有限公司 | Chemically induced stimulation of cleat formation in subterranean coal formation |
| CN107762549A (en) * | 2017-10-13 | 2018-03-06 | 临沂矿业集团有限责任公司 | The rock body quality of mine drilling anti-reflection formula gas pumping assay method in multistage interval |
| CN108868702A (en) * | 2018-06-21 | 2018-11-23 | 河南理工大学 | A kind of coal bed gas ultrasonic wave desorption extraction water discharge method |
| CN212003131U (en) * | 2020-03-31 | 2020-11-24 | 石家庄铁道大学 | Enhanced gas extraction system applying hot steam and microwave radiation in cooperation with permeability-increasing coal seam |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113216962A (en) | 2021-08-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113216962B (en) | Synergistic anti-reflection desorption promotion experimental system and method for ultrasonic activated fracturing fluid | |
| AU2014336858B2 (en) | Method for enhanced fuel gas extraction by coal mine underground gas-liquid dual-phase alternating phase-driven fracturing of coal body | |
| CN109723404B (en) | Naked eye plugging device and method for coal gas exploration well | |
| CN102182499B (en) | Hydrofracturing-based method and equipment for diminishing dust and eliminating outburst of coal bed | |
| CN100516457C (en) | Chemical pulse compound unplugging method | |
| RU2358100C2 (en) | Procedure of hydraulic break of reservoir in well | |
| CN104632174A (en) | Coal seam liquid carbon dioxide fracturing device and method | |
| CN103924955A (en) | Shale gas well CO2 and slickwater mixing fracturing technology | |
| CN103233768B (en) | Horizontal-drilling staged-fracturing pressure relief method for underground coal bed | |
| CN112145144B (en) | Based on multistage liquid CO2Phase-change composite fracturing transformation system and method | |
| CN112832728B (en) | Shale reservoir fracturing method based on methane multistage combustion and explosion | |
| CN204419145U (en) | Coal seam liquid carbon dioxide fracturing device | |
| CN110578505B (en) | Drilling deslagging and oscillation fracturing gas extraction system and method based on nano fluid | |
| CN113236217A (en) | Device and method for permeability increasing of low-permeability coal seam by using high-power ultrasonic waves | |
| CN114165197B (en) | Pressure-relief and permeability-increasing device and method for pulse hydraulic fracturing coal seam | |
| CN206957684U (en) | A kind of roof fracturing system | |
| WO2012122636A1 (en) | Method and apparatus of hydraulic fracturing | |
| WO2019075885A1 (en) | Method of reforming coal-bed gas well employing controllable shock waves in combination with surge water injection pressurization | |
| CN109488299B (en) | Hydraulic fracturing softening device and method for hard rock of fully-mechanized rock-digging roadway | |
| CN106761650A (en) | Oil, many microcrack pressure break block releasing techniques of well | |
| RU2322586C2 (en) | Method for methane removal from coal deposit seams | |
| CN111236894A (en) | Seabed shallow layer natural gas hydrate exploitation device | |
| CN111119828B (en) | Method for fracturing coal bed gas reservoir by using nitrogen foam fracturing fluid | |
| RU2720717C1 (en) | Intensification method for well operation | |
| RU2485306C1 (en) | Method of hydraulic fracturing of well formation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |