CN111255430A - Hydraulic sand fracturing system and fracturing method - Google Patents
Hydraulic sand fracturing system and fracturing method Download PDFInfo
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- 239000004576 sand Substances 0.000 title claims abstract description 107
- 238000000034 method Methods 0.000 title claims abstract description 25
- 238000000605 extraction Methods 0.000 claims abstract description 67
- 239000003245 coal Substances 0.000 claims abstract description 35
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 27
- 238000007599 discharging Methods 0.000 claims abstract description 17
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 103
- 238000007789 sealing Methods 0.000 claims description 35
- 239000002002 slurry Substances 0.000 claims description 18
- 239000006004 Quartz sand Substances 0.000 claims description 9
- 239000004568 cement Substances 0.000 claims description 6
- 238000005553 drilling Methods 0.000 claims description 6
- 229920002635 polyurethane Polymers 0.000 claims description 6
- 239000004814 polyurethane Substances 0.000 claims description 6
- 239000011083 cement mortar Substances 0.000 claims description 5
- 238000010276 construction Methods 0.000 claims description 5
- 230000009471 action Effects 0.000 claims description 4
- 238000004140 cleaning Methods 0.000 claims description 4
- 238000005086 pumping Methods 0.000 claims description 4
- 238000003825 pressing Methods 0.000 claims description 3
- 239000012530 fluid Substances 0.000 description 6
- 230000008030 elimination Effects 0.000 description 5
- 238000003379 elimination reaction Methods 0.000 description 5
- 239000003814 drug Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 239000011435 rock Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 229920001730 Moisture cure polyurethane Polymers 0.000 description 1
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
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- 239000000203 mixture Substances 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
- E21B43/267—Methods for stimulating production by forming crevices or fractures reinforcing fractures by propping
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/13—Methods or devices for cementing, for plugging holes, crevices or the like
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/006—Production of coal-bed methane
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/18—Repressuring or vacuum methods
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
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- 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
- E21F7/00—Methods or devices for drawing- off gases with or without subsequent use of the gas for any purpose
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Abstract
The invention provides a hydraulic sand fracturing system which comprises a drill hole constructed from a roadway to a coal seam to be extracted, wherein an extraction pipe with an end part extending to the coal seam to be extracted is arranged in the drill hole, and a through hole is formed in the partial surface of the extraction pipe, which is positioned in the coal seam area to be extracted; the end part, located in the roadway, of the extraction pipe is respectively connected with an exhaust pipeline and a fracturing pipeline through a tee joint, the other end of the fracturing pipeline is connected with a sand adding device, the sand adding device comprises a cavity, an inlet and an outlet are respectively arranged at two axial ends of the cavity, a sand adding opening is formed above the cavity, a sand discharging opening is formed below the cavity, and valves are arranged on the sand adding opening and the sand discharging opening; the inlet is communicated with a water supply system, and the outlet is communicated with the sand adding pipeline; the invention also provides a hydraulic sand fracturing method. The hydraulic sand fracturing system and the fracturing method provided by the invention have the advantages that: through introducing the sand adding device, the sand adding fracturing is conveniently realized, the use is convenient, and the extraction efficiency is high.
Description
Technical Field
The invention relates to the technical field of coal mine gas extraction, in particular to a hydraulic sand fracturing system and a hydraulic sand fracturing method.
Background
In order to ensure safe production, gas extraction is needed before coal seam exploitation, at present, drilling is mainly adopted for coal seam construction, and gas in the coal seam is extracted from a pipeline in the drilling hole through hydraulic fracturing of the coal seam, however, for the coal seam with poor air permeability, coal seam cracks can be quickly sealed after hydraulic fracturing, so that the extraction effect is poor, and the outburst elimination time is long, and the patent application CN110005393A discloses that the fracturing effect is improved by adding quartz sand into water; however, the sand adding system provided by the method is complex, a large amount of calculation is needed to determine working parameters and specific working modes, and the requirement of rapid construction of a mine is not met.
Disclosure of Invention
The invention aims to provide a hydraulic sand fracturing system and a hydraulic sand fracturing method which are simple in structure and convenient to work.
The invention solves the technical problems through the following technical scheme: a hydraulic sand adding fracturing system comprises a drill hole constructed from a roadway to a coal seam to be extracted, wherein an extraction pipe with an end part extending to the coal seam to be extracted is arranged in the drill hole, and a through hole is formed in the partial surface of the extraction pipe, which is positioned in the area of the coal seam to be extracted; the end part, located in the roadway, of the extraction pipe is respectively connected with an exhaust pipeline and a fracturing pipeline through a tee joint, the other end of the fracturing pipeline is connected with a sand adding device, the sand adding device comprises a cavity, an inlet and an outlet are respectively arranged at two axial ends of the cavity, a sand adding opening is formed above the cavity, a sand discharging opening is formed below the cavity, and valves are arranged on the sand adding opening and the sand discharging opening; the inlet is communicated with a water supply system, and the outlet is communicated with the sand adding pipeline.
During operation, if sand adding and fracturing are not needed, quartz sand does not need to be placed in the sand adding device, clean water is directly supplied to the extraction pipe by an external water supply system to serve as fracturing fluid, the quartz sand is added into the sand adding device through the sand adding opening when the sand is needed, water is supplied to the sand adding device under the condition that valves of the sand adding opening and the sand discharging opening are in a closed state, and the fracturing fluid after sand adding is supplied to the extraction pipe. The fracturing fluid advances along the extraction pipe and is sprayed out of the through hole, cracks are generated in the coal seam to be extracted, the fracturing pipeline is closed after the fracturing operation is finished, the exhaust pipeline is opened, and gas in the coal seam to be extracted enters the extraction pipe from the through hole for extraction and outburst elimination through negative pressure extraction, so that outburst elimination extraction is quickly and safely realized, the production safety is ensured, and the extraction efficiency is improved; and after the sand fracturing is finished, the residual quartz sand can be discharged through the sand discharge port.
Preferably, the tee bend is provided with the valve respectively with two branches of exhaust pipe and fracturing pipeline intercommunication, adopts automatic gate valve on at least the branch road with the sand-adding pipeline intercommunication, automatic gate valve includes the flashboard of following the linear motion switching and the sharp drive unit of drive flashboard action.
Preferably, a first hole sealing section is arranged at one end, close to the roadway, in the drill hole, and a second hole sealing section is arranged at a position, from the first hole sealing section to the through hole, of the lowest part of the extraction pipe; the first hole sealing section is used for sealing a hole by using polyurethane, and the length of the first hole sealing section is not less than 2 m; and sealing the second sealing section by using cement mortar.
The invention also provides a hydraulic sand fracturing method, which comprises the following steps:
step A: drilling holes from a low roadway to a high coal seam to be extracted;
and B: an extraction pipe, a grouting pipe and a slurry return pipe are respectively arranged in the drill hole, the end part of the extraction pipe is provided with a through hole which can be plugged, the through hole is approximately positioned at the central height position of the coal seam to be extracted, and the end part of the grouting pipe is 3-4 m away from the mouth part of the drill hole; the end part of the pulp return pipe is 1m-2m below the through hole at the lowest part of the extraction pipe;
and C: the method comprises the following steps that the end part, located in a roadway, of an extraction pipe is connected with an exhaust pipeline and a fracturing pipeline through a tee joint respectively, the exhaust pipeline is communicated with a gas pumping and discharging system, and the other end of the fracturing pipeline is connected with a sand adding device;
step D: arranging a first hole sealing section at one end of the drill hole in the roadway;
step E: after the construction of the first hole sealing section is finished, injecting cement slurry into the hole through the grouting pipe by using a grouting pump until the slurry return pipe returns, and cleaning the slurry return pipe by using clear water;
step F: after the cement slurry is solidified, performing secondary grouting from the slurry return pipe, sealing the through hole of the extraction pipe after the slurry return of the extraction pipe is finished, continuing performing pressurized grouting through the slurry return pipe, opening the through hole of the extraction pipe after the grouting is finished, cleaning the extraction pipe by using clear water, and obtaining a second hole sealing section after the secondary grouting is solidified;
step G: pressing clear water into the coal seam to be extracted through the extraction pipe to form a crack; and then quartz sand is put into a sand adding device for sand adding and fracturing.
Preferably, the sand adding device comprises a cavity, an inlet and an outlet are respectively arranged at two axial ends of the cavity, a sand adding port is arranged above the cavity, a sand discharging port is arranged below the cavity, and valves are respectively arranged at the sand adding port and the sand discharging port; the inlet is communicated with a water supply system, and the outlet is communicated with the sand adding pipeline.
Preferably, the first hole sealing section is a polyurethane hole sealing section with the length not less than 2 m; the polyurethane is prepared from the medicine A and the medicine B according to the mass part ratio of 1: 1; the A medicine is polyurethane prepolymer, and the B medicine is a mixture of curing agent and auxiliary agent.
Preferably, the cement mortar of the second hole sealing section is prepared according to the mass part ratio of 0.8:1 of water and cement.
Preferably, the second grouting is carried out 12 hours after the first grouting, and the pressure of the grouting return pipe under pressure is not less than 4 MPa.
Preferably, the tee bend is provided with the valve respectively with two branches of exhaust duct and fracturing pipeline intercommunication, and the branch road of at least with fracturing pipeline intercommunication is automatic gate valve, automatic gate valve includes the flashboard of following the rectilinear motion switching and the sharp drive unit of drive flashboard action.
Preferably, in the step G, at least 50t of clean water is pressed into the extraction pipe, and then sand fracturing is performed according to the proportion of adding 9.6kg of sand into every 10t of water.
The hydraulic sand fracturing system and the fracturing method provided by the invention have the advantages that: by introducing the sand adding device, sand adding fracturing is conveniently realized, the use is convenient, and the extraction efficiency is high; automatic control of sand fracturing is realized through the automatic gate valve, and safety is improved.
Drawings
FIG. 1 is a schematic diagram of a hydraulic sanding system provided by an embodiment of the present invention;
FIG. 2 is a schematic diagram of an automatic gate valve of a hydraulic sanding system provided in accordance with an embodiment of the present invention;
fig. 3 is a schematic diagram of the internal structure of a borehole of the hydraulic sanding system according to the embodiment of the present invention.
Detailed Description
In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.
As shown in fig. 1, the embodiment provides a hydraulic sand fracturing system, which comprises a drill hole 3 constructed from a roadway 1 to a coal seam 2 to be extracted, an extraction pipe 4 with the end part extending to the coal seam 2 to be extracted is arranged in the drill hole 3, a through hole 41 is arranged on the partial surface of the extraction pipe 4 in the coal seam 2 to be extracted, the end part of the extraction pipe 4 in the roadway is respectively connected with an exhaust pipeline 43 and a fracturing pipeline 44 through a tee joint 42, the exhaust pipeline 43 is connected with a gas pumping and exhausting system, the other end of the fracturing pipeline 44 is connected with a sand adding device 5, the sand adding device 5 comprises a cylindrical cavity 51, an inlet 52 communicated with a water supply system and an outlet 53 communicated with the fracturing pipeline 44 are respectively arranged at two axial ends of the cavity 51, a sand adding port 54 is arranged above the cavity 51, a sand discharging port 55 is arranged below the cavity 51, and valves (not shown) are respectively arranged on the sand adding port 54 and the sand discharging port 55.
During operation, if sand adding and fracturing are not needed, quartz sand does not need to be placed in the sand adding device, clean water is directly supplied to the extraction pipe 4 by an external water supply system to serve as fracturing fluid, the quartz sand is added into the sand adding device 5 through the sand adding opening when sand adding is needed, water is supplied to the sand adding device under the condition that valves of the sand adding opening 54 and the sand discharging opening 55 are in a closed state, and the fracturing fluid after sand adding is supplied to the extraction pipe 4. The fracturing fluid advances along the extraction pipe 4 and is sprayed out of the through hole 41, cracks are generated in the coal seam 2 to be extracted, the fracturing pipeline 44 is closed after the fracturing operation is finished, the exhaust pipeline 43 is opened, and gas in the coal seam 2 to be extracted enters the extraction pipe 4 from the through hole 41 for extraction and outburst elimination through negative pressure extraction, so that outburst elimination extraction is quickly and safely realized, the production safety is ensured, and the extraction efficiency is improved; and after the sand fracturing is finished, the residual quartz sand can be discharged through the sand discharge port 55.
Two branches of the tee joint 42, which are communicated with the exhaust pipeline 43 and the fracturing pipeline 44, are respectively provided with a valve, wherein at least the branch communicated with the fracturing pipeline 44 adopts an automatic gate valve 6, so that the remote control of the fracturing pipeline 44 is realized, and the liquid leakage is prevented from hurting operators when the fracturing pipeline 44 is opened and closed; referring to fig. 2, the automatic gate valve 6 includes a gate plate 61 moving linearly and a linear driving unit 62 driving the gate plate 61 to move, the linear driving unit 62 may be a driving mechanism such as an oil cylinder, an air cylinder, a screw nut pair, etc., in this embodiment, the air cylinder is selected, and air with a pressure of 0.3-0.6MPa is used as power, and a control switch of the air cylinder is remotely arranged by an electric wire, thereby conveniently realizing remote control.
Before fracturing and extraction, a drill hole needs to be plugged, referring to fig. 3, in the embodiment, a first hole sealing section 31 is arranged at one end, close to a roadway, of the drill hole, and a second hole sealing section 32 is arranged at a through hole 41 from the first hole sealing section 31 to the lowest part of an extraction pipe 4, wherein the first hole sealing section 31 is made of a polyurethane material with the length not less than 2 meters, and the main purpose of the method is to fix all parts with a rock wall of the drill hole; the second hole sealing section 32 is made of cement mortar, and cracks of a rock wall in the drilling process are sealed through grouting filling, so that gas is prevented from flowing to other positions along the cracks.
The extraction pipe 4 provided by the implementation adopts a multi-section spliced seamless steel pipe with the diameter of 25mm, so that the extraction pipe 4 can be arranged in the drill hole 3 section by section in a roadway; the joint of the seamless steel pipe adopts a special joint for connection and is wound and sealed by a thread seal tape.
The concrete dimensions of the sand adding device 5 selected in this embodiment are as follows: the diameter of the cavity 51 is 194mm, the wall thickness is 22mm, and the two ends of the cavity 51 are in streamline arc structures and the thickness is 30 mm; the length of the whole cavity 51 is 1500mm, the pressure resistance of the cavity is not less than 60MPa, the diameters of the inlet 52 and the outlet 53 are both 19mm, and the diameters of the sand adding port 54 and the sand discharging port 55 are respectively 31.5 mm.
The hydraulic sand fracturing method is illustrated below by taking a coal seam of a working face of Huainan mining group as an example, and the coal seam is solidThe measured gas pressure is 2.8MPa, and the gas content is 8.4m3T, original water content of coal bed is 1.6%, and permeability coefficient of coal bed is 0.022m2V (MPad); a plurality of extraction drill holes are constructed in a roadway, and the specific method comprises the following steps:
step A: constructing a drill hole 3 from a roadway 1 at a low position to a coal seam 2 to be extracted at a high position;
and B: an extraction pipe 4, a grouting pipe 7 and a slurry return pipe 8 are respectively arranged in the drill hole 3, a through hole 41 capable of being plugged is formed in the end part of the extraction pipe 4, the through hole 41 is approximately located at the central height position of the coal seam 2 to be extracted, and the end part of the grouting pipe 7 is 3-4 m away from the opening part of the drill hole; the end part of the pulp return pipe 8 is positioned 1m-2m below the through hole 41 at the lowest part of the extraction pipe 4;
and C: the end part, located in a roadway, of the extraction pipe 4 is respectively connected with an exhaust pipeline 43 and a fracturing pipeline 44 through a tee joint 42, the exhaust pipeline 43 is communicated with a gas pumping and drainage system, and the other end of the fracturing pipeline 44 is connected with a sand adding device 5; the sand adding device can use the sand adding device in the prior art
Step D: arranging a first hole sealing section 31 at one end of the drill hole 2 in the roadway 1; the first hole sealing section 31 is made of a polyurethane material, the length of the first hole sealing section is not less than 2m, the first hole sealing section is made of polyurethane bag foaming, and the polyurethane is prepared by mixing the medicine A and the medicine B in a ratio of 1:1 in parts by weight; in the embodiment, the A medicine is polyurethane prepolymer, and the B medicine is a mixture of curing agent and auxiliary agent; the extraction pipe 4, the grouting pipe 7 and the slurry return pipe 8 are fixedly matched with the drill hole 2 through the first hole sealing section 31;
step E: after the first hole sealing section 31 is constructed, cement slurry is injected into the drill hole 2 through the grouting pipe 7 by a grouting pump until the slurry return pipe 8 returns slurry, namely the cement slurry rises to the upper port of the slurry return pipe 8, and then the slurry return pipe 8 is cleaned by clear water to prevent the slurry return pipe 8 from being blocked by the slurry;
step F: after cement slurry is solidified, secondary grouting is performed from the slurry return pipe 8, the through hole 41 of the extraction pipe is sealed after slurry return of the extraction pipe 4 is performed, pressurized grouting is continuously performed through the slurry return pipe 8, the pressure of the pressurized grouting in the embodiment is not less than 4MPa, a large number of cracks are formed due to the fact that rock walls around the drill hole are damaged in the drilling construction process, the tightness of hole sealing is affected, the cracks can be sealed through the pressurized grouting, and the hole sealing effect is guaranteed. After grouting is finished, opening the through hole 41 of the extraction pipe 4, cleaning the extraction pipe 4 by using clear water, obtaining a second hole sealing section 32 after secondary grouting solidification, wherein the second hole sealing section 32 realizes filling and plugging of a gap inside the drill hole 2, and prevents gas from flowing to other positions along the drill hole 2; the cement mortar is prepared according to the mass ratio of water to cement of 0.8: 1.
Step G: and (3) pressing clear water into the extraction pipe 4 by using a fracturing pump to enable the coal seam to be extracted to form cracks so as to ensure that the sand adding channel is smooth, adding quartz sand into the sand adding device 5 to perform sand adding fracturing so as to ensure that the pores are kept open, and then performing extraction operation.
This implement structure that adds sand device 5 that provides includes the cavity 51 of tube-shape, cavity 51 axial both ends are equipped with respectively with the import 52 of water supply system intercommunication and with the export 53 of fracturing pipeline 44 intercommunication, cavity 51 top is provided with sand mouth 54, cavity 51 below is provided with row sand mouth 55, it all is provided with the valve to add sand mouth 54 and row sand mouth 55, specific size as follows: the diameter of the outer ring of the cavity 51 is 194mm, the wall thickness is 22mm, and the two ends of the cavity 51 are of streamline arc structures and the thickness is 30 mm; the length of the whole cavity 51 is 1500mm, the pressure resistance of the cavity is not less than 60MPa, the diameters of the inlet 52 and the outlet 53 are both 19mm, and the diameters of the sand adding port 54 and the sand discharging port 55 are respectively 31.5 mm.
The used fracturing pump is a BRW/200-56 type fracturing pump produced by Nanjing Liuhe coal mine machinery Co., Ltd, the flow is 200L/min, the inner diameter of the sand adding device 5 is about 150mm, the flow speed in the cavity 51 is about 0.19m/s, in order to ensure that the sand adding device 5 is not blocked, quartz sand can be dispersed when high-pressure water enters the cavity 51, the sand adding volume is 1/4 of the volume of the cavity 51, about 6.4L and the weight is 9.6kg, after long-term production observation and debugging, in the specific fracturing process, in order to ensure that the quartz sand is pressed into a hole and then smoothly enters a coal bed, a crack is formed on the coal body before sand adding, firstly 50t of clean water is used for fracturing to form the crack, then 9.6kg of quartz sand is added for sand adding and fracturing, all the quartz sand is basically pressed into the coal bed within 30 minutes, and the required water amount is about 10 t.
In hydraulic fracturing, due to the need of adding sand, the operation is often carried out on the orifice of the drill hole 2 and the high-pressure gate valve of the high-pressure pipeline, the potential danger of hurting people due to liquid leakage exists in the operation of personnel, two branches of the tee joint 42, the exhaust pipeline 43 and the fracturing pipeline 44 are respectively provided with a valve, wherein at least the branch communicated with the fracturing pipeline 44 adopts the automatic gate valve 6, so that the remote control of the fracturing pipeline 44 is realized, and the injury of the operating personnel due to liquid leakage when the fracturing pipeline 44 is opened and closed is prevented; referring to fig. 2, the automatic gate valve 6 includes a gate plate 61 moving linearly and a linear driving unit 62 driving the gate plate 61 to move, the linear driving unit 62 may be an oil cylinder, an air cylinder, a screw nut pair, or other driving mechanisms, in this embodiment, the air cylinder is selected, air with a pressure of 0.3-0.6MPa is used as power, and a control switch of the air cylinder is remotely arranged through an electric wire, so that remote control is conveniently achieved.
After fracturing is carried out by the method, the pure quantity investigation of the drainage of the hundreds of holes of the hydraulic fracturing section and the non-fracturing section is carried out, and the pure quantity of the hundreds of holes of the non-fracturing section is only 1m within 1 month after the drilling construction is finished3Min, the pure quantity of the hundred holes of the hydraulic fracturing section is 1.5-2.3 m3And the extraction effect is improved by 1.5-2.3 times per min, and the stability of the purity of the drilled hundred holes in the hydraulic fracturing section is good. The extraction rate standard reaching time of the fracturing extraction area is reduced by 26 days compared with that of the non-permeability-increasing area.
Claims (10)
1. The utility model provides a sand fracturing system is added to water conservancy which characterized in that: the method comprises the steps that a drill hole is formed in the roadway to be constructed in the coal seam to be extracted, an extraction pipe with the end part extending to the coal seam to be extracted is arranged in the drill hole, and through holes are formed in the partial surface of the extraction pipe, which is located in the coal seam area to be extracted; the end part, located in the roadway, of the extraction pipe is respectively connected with an exhaust pipeline and a fracturing pipeline through a tee joint, the other end of the fracturing pipeline is connected with a sand adding device, the sand adding device comprises a cavity, an inlet and an outlet are respectively arranged at two axial ends of the cavity, a sand adding opening is formed above the cavity, a sand discharging opening is formed below the cavity, and valves are arranged on the sand adding opening and the sand discharging opening; the inlet is communicated with a water supply system, and the outlet is communicated with the sand adding pipeline.
2. The hydraulic sanding fracturing system of claim 1, wherein: the tee joint is provided with the valve respectively with two branches of exhaust pipe and fracturing pipeline intercommunication, adopts automatic gate valve on at least the branch of with the pipeline intercommunication that adds sand, automatic gate valve includes the flashboard along the linear motion switching and the sharp drive unit of drive flashboard action.
3. The hydraulic sanding fracturing system of claim 1, wherein: a first hole sealing section is arranged at one end, close to the roadway, in the drill hole, and a second hole sealing section is arranged at the position, from the first hole sealing section to the through hole, of the lowest part of the extraction pipe; the first hole sealing section is used for sealing a hole by using polyurethane, and the length of the first hole sealing section is not less than 2 m; and sealing the second sealing section by using cement mortar.
4. A hydraulic sand fracturing method is characterized in that: the method comprises the following steps:
step A: drilling holes from a low roadway to a high coal seam to be extracted;
and B: an extraction pipe, a grouting pipe and a slurry return pipe are respectively arranged in the drill hole, the end part of the extraction pipe is provided with a through hole which can be plugged, the through hole is approximately positioned at the central height position of the coal seam to be extracted, and the end part of the grouting pipe is 3-4 m away from the mouth part of the drill hole; the end part of the pulp return pipe is 1m-2m below the through hole at the lowest part of the extraction pipe;
and C: the method comprises the following steps that the end part, located in a roadway, of an extraction pipe is connected with an exhaust pipeline and a fracturing pipeline through a tee joint respectively, the exhaust pipeline is communicated with a gas pumping and discharging system, and the other end of the fracturing pipeline is connected with a sand adding device;
step D: arranging a first hole sealing section at one end of the drill hole in the roadway;
step E: after the construction of the first hole sealing section is finished, injecting cement slurry into the hole through the grouting pipe by using a grouting pump until the slurry return pipe returns, and cleaning the slurry return pipe by using clear water;
step F: after the cement slurry is solidified, performing secondary grouting from the slurry return pipe, sealing the through hole of the extraction pipe after the slurry return of the extraction pipe is finished, continuing performing pressurized grouting through the slurry return pipe, opening the through hole of the extraction pipe after the grouting is finished, cleaning the extraction pipe by using clear water, and obtaining a second hole sealing section after the secondary grouting is solidified;
step G: pressing clear water into the coal seam to be extracted through the extraction pipe to form a crack; and then quartz sand is put into a sand adding device for sand adding and fracturing.
5. The hydraulic sand fracturing method of claim 4, wherein: the sand adding device comprises a cavity, an inlet and an outlet are respectively arranged at two axial ends of the cavity, a sand adding opening is arranged above the cavity, a sand discharging opening is arranged below the cavity, and valves are respectively arranged at the sand adding opening and the sand discharging opening; the inlet is communicated with a water supply system, and the outlet is communicated with the sand adding pipeline.
6. The hydraulic sand fracturing method of claim 4, wherein: the first hole sealing section is a polyurethane hole sealing section with the length not less than 2 m.
7. The hydraulic sand fracturing method of claim 4, wherein: and cement mortar of the second hole sealing section is prepared according to the mass part ratio of water to cement of 0.8: 1.
8. The hydraulic sand fracturing method of claim 4, wherein: and performing secondary grouting after the primary grouting for 12 hours, wherein the pressure of the pressurized grouting of the slurry return pipe is not less than 4 MPa.
9. The hydraulic sand fracturing method of claim 4, wherein: the tee joint is provided with the valve respectively with two branches of exhaust duct and fracturing pipeline intercommunication, and the branch road that communicates with the fracturing pipeline at least is automatic gate valve, automatic gate valve includes the flashboard of following the rectilinear motion switching and the sharp drive unit of drive flashboard action.
10. The hydraulic sand fracturing method of claim 4, wherein: and G, at least pressing 50t of clean water into the extraction pipe, and then performing sand adding and fracturing according to the proportion of adding 9.6kg of sand into every 10t of water.
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