CN112127854A - Staged fracturing and extraction method for long drill hole of coal seam and pressure-extraction integrated device - Google Patents
Staged fracturing and extraction method for long drill hole of coal seam and pressure-extraction integrated device Download PDFInfo
- Publication number
- CN112127854A CN112127854A CN202011007065.0A CN202011007065A CN112127854A CN 112127854 A CN112127854 A CN 112127854A CN 202011007065 A CN202011007065 A CN 202011007065A CN 112127854 A CN112127854 A CN 112127854A
- Authority
- CN
- China
- Prior art keywords
- fracturing
- hole
- ball
- pipe
- pressure
- 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.)
- Pending
Links
- 239000003245 coal Substances 0.000 title claims abstract description 59
- 238000000605 extraction Methods 0.000 title claims abstract description 54
- 238000007789 sealing Methods 0.000 claims abstract description 53
- 239000012530 fluid Substances 0.000 claims abstract description 51
- 238000000034 method Methods 0.000 claims abstract description 41
- 239000011148 porous material Substances 0.000 claims abstract description 20
- 230000001681 protective effect Effects 0.000 claims abstract description 12
- 238000005553 drilling Methods 0.000 claims description 33
- 239000002002 slurry Substances 0.000 claims description 20
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 17
- 238000010276 construction Methods 0.000 claims description 16
- 239000012266 salt solution Substances 0.000 claims description 12
- 230000009471 action Effects 0.000 claims description 8
- 239000004568 cement Substances 0.000 claims description 8
- 230000008569 process Effects 0.000 claims description 7
- 239000004576 sand Substances 0.000 claims description 6
- 230000011218 segmentation Effects 0.000 claims description 6
- 230000005484 gravity Effects 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 5
- 230000000149 penetrating effect Effects 0.000 claims description 5
- 239000011347 resin Substances 0.000 claims description 5
- 229920005989 resin Polymers 0.000 claims description 5
- 238000013461 design Methods 0.000 claims description 4
- 238000006073 displacement reaction Methods 0.000 claims description 4
- 238000002360 preparation method Methods 0.000 claims description 4
- 238000012856 packing Methods 0.000 claims description 3
- 239000013049 sediment Substances 0.000 claims description 3
- 238000010008 shearing Methods 0.000 claims description 3
- 238000007711 solidification Methods 0.000 claims description 3
- 230000008023 solidification Effects 0.000 claims description 3
- 238000005406 washing Methods 0.000 claims description 3
- 230000009977 dual effect Effects 0.000 claims 1
- 238000005086 pumping Methods 0.000 abstract description 12
- 230000000694 effects Effects 0.000 abstract description 8
- 238000005516 engineering process Methods 0.000 description 6
- 230000035699 permeability Effects 0.000 description 6
- 239000007788 liquid Substances 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 238000009412 basement excavation Methods 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
Images
Classifications
-
- 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
- E21B43/14—Obtaining from a multiple-zone well
-
- 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
-
- 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
- E21B34/00—Valve arrangements for boreholes or wells
- E21B34/06—Valve arrangements for boreholes or wells in wells
- E21B34/063—Valve or closure with destructible element, e.g. frangible disc
-
- 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
- E21B34/00—Valve arrangements for boreholes or wells
- E21B34/06—Valve arrangements for boreholes or wells in wells
- E21B34/08—Valve arrangements for boreholes or wells in wells responsive to flow or pressure of the fluid obtained
-
- 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
- E21B37/00—Methods or apparatus for cleaning boreholes or wells
- E21B37/06—Methods or apparatus for cleaning boreholes or wells using chemical means for preventing or limiting, e.g. eliminating, the deposition of paraffins or like substances
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/006—Production of coal-bed methane
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
- E21B43/261—Separate steps of (1) cementing, plugging or consolidating and (2) fracturing or attacking the formation
Landscapes
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Drilling And Exploitation, And Mining Machines And Methods (AREA)
Abstract
The invention discloses a method for staged fracturing and extraction of long drill holes of a coal seam and a pressure and extraction integrated device, wherein the method comprises the steps of hole sealing, fracturing and extraction; wherein, the hole sealing adopts the grouting hole sealing of the drill hole according to the full hole section under the condition that the sieve pores have the protective films; fracturing adopts a dissolvable fracturing ball pitching staged fracturing mode, and fracturing fluid passing through a sieve mesh penetrates through the rubber sheet and the corresponding hole sealing part and then is communicated with the coal bed; a fracturing cover is fixed by the provisional fixation pin that can utilize fracturing pressure to cut off among the fracturing unit for the fracture to under the fracturing fluid effect, promote fracturing cover to move in order to cut off provisional fixation pin and expose the sieve mesh. The pressure pumping integrated device is used for fracturing and coal seam gas pumping of the method. The method has the advantages that the method can realize multi-section staged fracturing, and can apply the pitching fracturing method to the coal seam; the pressure and pumping integrated device has the functions of fracturing and pumping, can effectively improve the pumping efficiency and reduce the pumping cost.
Description
Technical Field
The invention belongs to the field of coal bed gas development, and particularly relates to a long drilling staged fracturing and extraction method of a coal bed and a pressure and extraction integrated device.
Background
Due to the complexity of geological conditions of coal in Chongqing areas, after main coal measure strata are deposited, strong tectonic movement is carried out, coal body structures are damaged strongly, coal beds of the Chongqing areas are mostly soft coal beds, the Chongqing areas have the characteristics of low coal bed hardness, high gas pressure and content, poor air permeability and the like, and the difficulty in extracting coal bed gas (gas) is high. Through many years of exploration, the hydraulic fracturing permeability increase is one of key technical measures for gas extraction of a low-permeability coal seam, a core technology of water treatment of gas and a working mode of firstly pressing and then pumping are formed, and a certain effect is achieved. However, this method has the following limitations: (1) the conventional fracturing drilling mainly adopts floor roadway cross-layer drilling or the coal seam bedding drilling for fracturing, and the construction amount of the roadway and the drilling is large and the cost is high; (2) each fracturing drill hole is usually fractured at the bottom of the hole only once, so that the number of the fracturing drill holes is large, the hole sealing and fracturing cost is high, the single-hole fracture influence range is small, the gas extraction quantity is small, the drill hole utilization rate is low, the extraction efficiency is low, the standard reaching time is long, and the extraction, extraction and excavation deployment are short; the method for increasing the permeability of large-area regionalized hydraulic fracturing and efficiently extracting gas is urgently needed to be developed.
Along with the development of unconventional oil and gas industry, horizontal well drilling technology and multi-stage staged fracturing technology are rapidly developed, and accordingly the horizontal well drilling technology is widely applied to long-borehole drilling in coal mines, but in the staged fracturing technology, due to the limitation of narrow space in coal mines, huge ground fracturing equipment cannot be accommodated, the power of an underground fracturing pump set is limited, the construction displacement is far smaller than that of the ground fracturing pump set, the requirement for increasing the permeability of the whole long-borehole fracturing cannot be met, and therefore research and development of the coal-bed directional long-borehole staged fracturing permeability increasing and gas extraction technology and equipment are urgently needed. The uniform permeability increase of the regional coal seam is realized, the gas extraction effect is improved, and the gas dynamic disaster risk is reduced.
At present, the research of the underground coal mine directional long drilling hole staged fracturing technology is carried out domestically, a pitching fracturing method of bag staged hole sealing is generally adopted, although the method can realize the reutilization of a fracturing tool, in the practical application of the method, the fracturing tool is difficult to take out due to the fact that the fracturing tool falls off after staged fracturing in the open hole directional long drilling hole, once the fracturing tool cannot be taken out due to the limitation of the size of a sliding sleeve, a sliding sleeve opening of the sliding sleeve becomes a unique channel for communicating a coal bed with a drilling hole, the pumping efficiency after the fracturing is greatly influenced due to the limitation of the opening size of the sliding sleeve opening, the application place of the method is greatly limited, and the method is particularly difficult to be applied to the coal bed with serious block falling phenomenon. For this reason, improvements are required.
Disclosure of Invention
The invention aims to overcome the defect that the existing ball throwing fracturing is difficult to apply to the coal seam, and provides a method for staged fracturing and extraction of long drilled holes of the coal seam, wherein hole sealing of the method is carried out on the drilled holes according to a full-hole section grouting hole sealing mode under the condition that a sieve hole has a protective film; fracturing adopts a dissolvable fracturing ball pitching staged fracturing mode, fracturing fluid penetrating through a sieve mesh penetrates through a rubber sheet and a hole sealing section corresponding to a hole sealing part and then is communicated with a coal bed, and fracturing is carried out by replacing the fracturing fluid with a saline solution; the dissolvable fracturing ball is made of low-density resin materials, the specific gravity of the dissolvable fracturing ball is smaller than that of fracturing fluid, the dissolvable fracturing ball can be soaked and dissolved through salt solution, a fracturing sleeve in a fracturing device for fracturing is fixed by a temporary fixing pin which can be sheared by fracturing pressure, the dissolvable fracturing ball pushes the fracturing sleeve to move under the action of the fracturing fluid so as to shear the temporary fixing pin and expose a sieve hole, and after fracturing construction is completely completed, the salt solution is used as displacing liquid to dissolve the fracturing ball, so that full-path extraction is realized. The method adopts full-hole section grouting and hole sealing, so that the fracturing device does not need to be taken out for recycling after fracturing and extraction are finished, and can be mined along with media in the coal seam mining process, so that the block falling phenomenon does not need to be considered, and the method can be conveniently used for fracturing and extraction of the coal seam. The second purpose of the invention is to provide a pressure and extraction integrated device for realizing the integrated operation of dissolving ball fracturing and gas extraction, so as to improve the construction convenience and reduce the extraction cost.
In order to achieve the first object, the invention adopts the following technical scheme.
A method for staged fracturing and extraction of long drill holes of a coal seam comprises the steps of hole sealing, fracturing and extraction; wherein, hole sealing is carried out according to a full-hole section grouting hole sealing mode under the condition that a protective film is wrapped outside the sieve holes; fracturing adopts a dissolvable fracturing ball pitching staged fracturing mode, fracturing fluid penetrating through a sieve mesh penetrates through a rubber sheet and a hole sealing section corresponding to a hole sealing part and then is communicated with a coal bed, and fracturing is carried out by replacing the fracturing fluid with a saline solution; the dissolvable fracturing ball is made of low-density resin materials, the specific gravity of the dissolvable fracturing ball is smaller than that of fracturing fluid, the dissolvable fracturing ball can be soaked and dissolved through salt solution, a fracturing sleeve in the fracturing device for fracturing is fixed by a temporary fixing pin which can be cut by fracturing pressure, and the dissolvable fracturing ball pushes the fracturing sleeve to move under the action of the fracturing fluid so as to cut the temporary fixing pin and expose a sieve pore.
By adopting the scheme, the hole sealing is carried out according to the full-hole section grouting hole sealing mode under the condition that the sieve holes have the protective films; fracturing adopts a dissolvable fracturing ball pitching staged fracturing mode, fracturing fluid penetrating through a sieve mesh penetrates through a rubber sheet and a hole sealing section corresponding to a hole sealing part and then is communicated with a coal bed, and fracturing is carried out by replacing the fracturing fluid with a saline solution; the dissolvable fracturing ball is made of low-density resin materials, the specific gravity of the dissolvable fracturing ball is smaller than that of fracturing fluid, the dissolvable fracturing ball can be soaked and dissolved through salt solution, a fracturing sleeve in a fracturing device for fracturing is fixed by a temporary fixing pin which can be sheared by fracturing pressure, the dissolvable fracturing ball pushes the fracturing sleeve to move under the action of the fracturing fluid so as to shear the temporary fixing pin and expose a sieve hole, and after fracturing construction is completely completed, the salt solution is used as displacing liquid to dissolve the fracturing ball, so that full-path extraction is realized. Because the method adopts the hole sealing mode of the full depth direction of the drilled hole, the hole sealing is not required to be carried out in a subsection mode; and after fracturing and extraction, fracturing devices or tools such as fracturing pipes do not need to be taken out, the operation is convenient, the efficiency is high, the construction efficiency can be effectively improved, and the construction cost is reduced. And the fracturing sleeve can be arranged as required, is not limited by the size and specification of the conventional sliding sleeve, and can meet the length requirement of 2-3 meters.
Preferably, the salt solution is injected as a displacement fluid for the fracturing fluid after completion of all staged fracturing. Compared with staged injection of replacement fluid, the dissolvable fracturing ball with the plugging effect caused by the replacement fluid can be prevented from being dissolved in the fracturing process, the plugging effect is weakened, and the staged fracturing effect is reduced.
Further preferably, the method is carried out according to the following steps:
the method comprises the following steps that firstly, a long drilling driller conducts directional long drilling of the coal seam along the coal seam trend in the coal seam, the drilling length is more than 200 meters, and the hole diameter is not less than 120 mm;
secondly, preparing fracturing, namely performing on-site preparation work of a hydraulic fracturing pump, a sand adding pump set, a high-pressure manifold, a staged packing and fracturing tool, fracturing fluid and fracturing sand according to fracturing construction requirements;
thirdly, determining a segmentation scheme, and designing the number of the directional long drill holes of the coal seam and the corresponding segment length according to the long drill hole forming data;
fourthly, preparing a fracturing device, preparing and forming the corresponding pipe section members of the fracturing device according to the segmentation quantity and the corresponding indexing length design result, and connecting the pipe section members into the fracturing device;
fifthly, placing a drilling hole dredging and fracturing device, after dredging a well, washing the well, and removing sediments in the hole, placing the main body part of the fracturing device into the drilling hole to a set position, exposing the orifice of a fracturing pipe of the fracturing device outside the drilling hole, and centralizing the fracturing pipe by using a centralizer and making the fracturing pipe concentric with the drilling hole;
sixthly, sealing and fixing the hole, namely injecting cement slurry from the grouting pipe until the slurry return pipe returns slurry, performing secondary grouting by using the slurry return pipe so as to fill the annular space between the fracturing device and the inner wall of the drilled hole with the cement slurry, and waiting for solidification;
seventhly, connecting the fracturing device with a fracturing pump, and connecting an exposed pipe orifice of the fracturing device with the fracturing pump through a high-pressure pipeline;
the eighth step, throwing ball for fracturing, throwing a dissolvable fracturing ball matched with the fracturing sleeve of the corresponding fracturing section into the fracturing pipe, starting a fracturing pump, and throwing the dissolvable fracturing ball to a ball seat part of the fracturing sleeve of the corresponding section by fracturing fluid according to a pressure value lower than the fracturing pressure so as to realize the sealing of the fracturing pipe and the fracturing section;
step nine, boosting pressure and fracturing, continuously injecting water and pressurizing to enable the pressure of the fracturing fluid to be raised to the range of the fracturing pressure, applying the fracturing pressure through a dissolvable fracturing ball, shearing off a corresponding temporary fixing pin to enable a fracturing sleeve to move so as to open a sieve pore, utilizing the fracturing fluid to penetrate through a protective rubber sheet, forming a jet flow channel communicated with a coal bed on a corresponding hole sealing section, and then performing anti-reflection fracturing on the coal bed of the fracturing section;
tenth step, judging whether the fracturing construction is finished or not, and judging whether a fracturing section which is not fractured exists in a fracturing section adjacent to the fracturing section; if yes, returning to the ninth step; if not, executing the next step;
step eleven, injecting a saline solution, and injecting the saline solution with a set proportion to replace fracturing fluid, wherein the saline solution is used for dissolving fracturing balls;
the twelfth step, maintaining the pressure, namely maintaining the pressure for a set time after injecting the saline solution with a set concentration and a set amount, so that after the fracturing balls are dissolved, all the fracturing sections can be communicated through a fracturing pipe;
and thirteenth, gas extraction, namely connecting the fracturing pipe of the fracturing device with an extraction pipeline, and performing gas extraction.
The staged fracturing construction and gas extraction can be carried out smoothly, the construction efficiency is improved, and the construction cost is reduced.
Preferably, the set value of the fracturing pressure is 20MPa to 37 MPa. The hole sealing section positioned outside the sieve holes is ensured to form a channel for communicating the coal bed and the interior of the fracturing pipe through sieve hole jet flow, the coal bed is fully fractured, and the anti-reflection effect is improved.
Preferably, the fracturing pump consists of a single pump, or a double pump or a plurality of pumps are connected in parallel to form a fracturing pump group. The fracturing fluid can be selected according to different occasions and fracturing requirements, and flexible application is ensured. In the fracturing pump set scheme, only 1 fracturing pump is started when the dissolvable fracturing ball is delivered. Reduce energy consumption and ensure smooth and reliable ball throwing.
In order to achieve the second object, the present invention adopts the following technical solutions.
The coal seam long-drilled hole staged fracturing and extraction device comprises a fracturing pipe, wherein at least two sieve hole pipes with sieve holes are connected in series on the fracturing pipe, a fracturing sleeve is in sliding fit in the sieve hole pipes, a ball seat structure for accommodating a fracturing ball capable of being dissolved is arranged on the fracturing sleeve, a first retaining ring is arranged on the fracturing pipe located at the inner end of the fracturing sleeve through an annular groove and used for limiting the position of the fracturing sleeve during fracturing, and guide shoes are connected in series on a pipe section of the fracturing pipe close to the bottom of a drilled hole; from the hole bottom of the drill hole to the hole opening, inner hole channels of the ball seat structure on the fracturing sleeve are sequentially enlarged and can pass through the dissolvable fracturing ball which is close to the fracturing section and faces the direction of the hole bottom; a pressure relief bypass and a ball throwing bypass are arranged at the end part of the fracturing pipe exposed out of the drill hole, a pressure relief valve is arranged on the pressure relief bypass, and an outlet end of the pressure relief bypass is provided with an interface connected with a gas-water separator; the pressure relief bypass is detachably connected with a gas-water separator through the interface; the fracturing sleeve is fixedly connected with the sieve hole pipe through a temporary fixing pin; the fracturing sleeve can move along with the soluble fracturing ball in the process that the fracturing fluid pushes and presses the soluble fracturing ball so as to shear the temporary fixing pin and open the sieve pore; the outside of each sieve pore is wrapped with a sieve pore protective film; and a ball throwing valve is arranged on the ball throwing bypass.
By adopting the device of the scheme, at least two sieve hole pipes with sieve holes are connected in series on the fracturing pipe, so that a staged fracturing mode structure suitable for ball-throwing fracturing is formed, when the fracturing ball is a soluble ball, after fracturing is completed in all fracturing sections, fracturing fluid is replaced by using a salt solution, and the fracturing ball is dissolved, so that the interior of the fracturing pipe is smooth; meanwhile, the pipe orifice of the fracturing pipe is respectively provided with a ball throwing port and a gas-water separator interface through two bypasses and is controlled by corresponding control valves, so that the ball throwing port can realize fracturing ball throwing, the gas-water separator interface can be connected with a gas-water separator, and then a gas extraction system is connected, and the purpose that the fracturing pipe is used as a gas extraction pipe is realized, so that the gas extraction preparation work is reduced, the extraction efficiency is effectively improved, and the extraction cost is reduced. The first baffle ring is used for blocking a corresponding fracturing sleeve in the fracturing process, and fracturing pressure is transmitted to the fracturing sleeve through the pressure ball and then sequentially transmitted to a hole bottom rock body through the fracturing sleeve, the first baffle ring, the fracturing pipe and the guide shoe; the outside of each sieve pore is wrapped with a sieve pore protection film to form protection to the sieve pore when grouting and sealing the holes, so that the sieve pore is prevented from being blocked by hole sealing cement slurry, the films can be easily pierced by jet flow formed by fracturing fluid through the sieve pore, and a channel communicated with a coal bed is ejected at a hole sealing section to realize fracturing and gas extraction.
Preferably, a centralizer is arranged between the fracturing pipe and the inner wall of the drill hole, and the centralizer is close to the hole opening of the drill hole. So that the fracturing pipe can be temporarily fixed in the middle of the drilled hole, the size of the annular space is ensured to be uniform, and the reliability of hole sealing is ensured.
Preferably, a second retaining ring is further arranged on the fracturing pipe through another annular groove; the second baffle ring is in an elastic baffle ring structure; the fracturing sleeve front end is the toper, and the fracturing sleeve can utilize the toper structure expansion second of front end to keep off the ring under the exogenic action to move to the opposite side from one side that the second kept off the ring. After fracturing and fracturing are completed, the fracturing sleeve is limited between the two retaining rings, so that sieve holes are prevented from being blocked by the fracturing sleeve, and smoothness of fracturing and extraction channels is ensured; and the second baffle ring is outwards expanded under the extrusion of the front-end taper structure of the fracturing sleeve so as to form a space for the fracturing sleeve to pass through. Preferably, the inner hole of the first baffle ring is in a taper hole shape, and the taper hole and the outer taper of the fracturing sleeve form a taper fit structure so as to enhance the supporting strength of the fracturing sleeve on the dissolvable fracturing ball and improve the fracturing bearing capacity.
The invention has the advantages that the staged fracturing and extraction method can realize multistage staged fracturing, can conveniently and reliably apply the ball throwing fracturing method of the soluble ball to the coal bed without considering the dropping factor, and can realize gas extraction by using the fracturing pipe after the fracturing ball is dissolved by the saline solution; the pressure and pumping integrated device has the functions of fracturing and pumping, can effectively improve the pumping efficiency and reduce the pumping cost.
Drawings
Fig. 1 is a schematic structural view of the integrated press-drawing device of the present invention. This figure is also used to illustrate staged fracturing methods.
Fig. 2 is a schematic view of the connection structure of the fracturing sleeve and the perforated pipe in the device of the invention.
FIG. 3 is an enlarged view of portion A of FIG. 1 according to the present invention.
Detailed Description
The invention will be further described with reference to the drawings, but the invention is not limited thereby within the scope of the embodiments described.
The salt solution is injected as a displacement fluid of a fracturing fluid after all staged fracturing is completed; the method is specifically carried out according to the following steps:
the method comprises the following steps that firstly, a long drilling driller conducts directional long drilling of the coal seam along the coal seam trend in the coal seam, the drilling length is more than 200 meters, and the hole diameter is not less than 120 mm;
secondly, preparing fracturing, namely performing on-site preparation work of a hydraulic fracturing pump, a sand adding pump set, a high-pressure manifold, a staged packing and fracturing tool, fracturing fluid and fracturing sand according to fracturing construction requirements;
thirdly, determining a segmentation scheme, and designing the number of the directional long drill holes of the coal seam and the corresponding segment length according to the long drill hole forming data;
fourthly, preparing a fracturing device, preparing and forming the corresponding pipe section members of the fracturing device according to the segmentation quantity and the corresponding indexing length design result, and connecting the pipe section members into the fracturing device;
fifthly, placing a drilling hole dredging and fracturing device, after dredging a well, washing the well, and removing sediments in the hole, placing the main body part of the fracturing device into the drilling hole to a set position, exposing the orifice of a fracturing pipe of the fracturing device outside the drilling hole, and centralizing the fracturing pipe by using a centralizer and making the fracturing pipe concentric with the drilling hole;
sixthly, sealing and fixing the hole, namely injecting cement slurry from the grouting pipe until the slurry return pipe returns slurry, performing secondary grouting by using the slurry return pipe so as to fill the annular space between the fracturing device and the inner wall of the drilled hole with the cement slurry, and waiting for solidification;
seventhly, connecting the fracturing device with a fracturing pump, and connecting an exposed pipe orifice of the fracturing device with the fracturing pump through a high-pressure pipeline;
the eighth step, throwing ball for fracturing, throwing a dissolvable fracturing ball matched with the fracturing sleeve of the corresponding fracturing section into the fracturing pipe, starting a fracturing pump, and throwing the dissolvable fracturing ball to a ball seat part of the fracturing sleeve of the corresponding section by fracturing fluid according to a pressure value lower than the fracturing pressure so as to realize the sealing of the fracturing pipe and the fracturing section;
step nine, boosting pressure and fracturing, continuously injecting water and pressurizing to enable the pressure of the fracturing fluid to be raised to the range of the fracturing pressure, applying the fracturing pressure through a dissolvable fracturing ball, shearing off a corresponding temporary fixing pin to enable a fracturing sleeve to move so as to open a sieve pore, utilizing the fracturing fluid to penetrate through a protective rubber sheet, forming a jet flow channel communicated with a coal bed on a corresponding hole sealing section, and then performing anti-reflection fracturing on the coal bed of the fracturing section;
tenth step, judging whether the fracturing construction is finished or not, and judging whether a fracturing section which is not fractured exists in a fracturing section adjacent to the fracturing section; if yes, returning to the ninth step; if not, executing the next step;
step eleven, injecting a saline solution, and injecting the saline solution with a set proportion to replace fracturing fluid, wherein the saline solution is used for dissolving fracturing balls;
step ten, sealing holes and maintaining pressure, wherein after a salt solution with a set amount is injected, the sealing holes and the maintaining pressure are carried out for a set time, so that after the fracturing balls are dissolved, all fracturing sections can be communicated through fracturing pipes;
thirteenth step, connecting the extraction pipeline, connecting the gas-water separator by using a pressure relief bypass, and connecting the gas-water separator with an external extraction pipeline through an air extraction interface of the gas-water separator;
and fourteenth, gas extraction, namely opening a control valve on the pipeline to extract gas.
Wherein the set value of the fracturing pressure is 20MPa to 37 MPa; the fracturing pump consists of a single pump or a double pump or a plurality of pumps which are connected in parallel to form a fracturing pump group. In the fracturing pump set scheme, only 1 fracturing pump is started when the dissolvable fracturing ball is delivered.
In the method, secondary grouting hole sealing can be performed by utilizing the slurry return pipe of the fracturing device so as to enhance the hole sealing effect or eliminate the hidden trouble of poor hole sealing.
Embodiment 2, referring to fig. 1, 2, and 3, a coal seam long borehole staged fracturing and extraction device includes a fracturing pipe 1, where the fracturing pipe 1 is connected in series with at least two perforated pipes having sieve holes 9, the perforated pipes are in sliding fit with a fracturing sleeve 2, the fracturing sleeve 2 has a ball seat structure for receiving a fracturing ball 7, the fracturing pipe 1 located at the inner end of the fracturing sleeve 2 is provided with a first retaining ring 15 through an annular groove, the first retaining ring 15 is used for limiting the position of the fracturing sleeve 2 during fracturing, and a guide shoe 3 is connected in series on a pipe section of the fracturing pipe 1 near the bottom of the perforated hole; from the hole bottom of the drilled hole to the orifice, inner hole channels of the ball seat structure on the fracturing sleeve 2 are sequentially enlarged and can pass through the dissolvable fracturing ball 7 for fracturing close to the fracturing section towards the hole bottom direction; a pressure relief bypass 4 and a ball throwing bypass 11 are arranged at the end part of the fracturing pipe 1 exposed out of the drill hole, a pressure relief valve 5 is arranged on the pressure relief bypass 4, and an outlet end of the pressure relief bypass 4 is provided with a connector connected with a gas-water separator; the pressure relief bypass 4 is detachably connected with a gas-water separator 6 through the interface, and the gas-water separator 6 is provided with a separation gas outlet 6a and a separation liquid outlet 6 b; the fracturing sleeve 2 is fixedly connected with the sieve hole pipe through a temporary fixing pin 8; the fracturing sleeve 2 can move along with the soluble fracturing ball 7 in the process that the fracturing fluid pushes and presses the soluble fracturing ball 7 so as to shear the temporary fixing pin 8 and open the sieve hole 9; the outside of the sieve pore 9 is wrapped with a sieve pore protective film 10; and a ball throwing valve 12 is arranged on the ball throwing bypass 11. When the fracturing sleeve is manufactured, the diameter of the through hole in the sleeve wall of the fracturing sleeve meets the requirement of the extraction drift diameter, and is larger than the aperture of the fracturing sleeve only used for fracturing.
A centralizer 13 is arranged between the fracturing pipe 1 and the inner wall of the drill hole, and the centralizer 13 is close to the hole opening of the drill hole. A second retaining ring 14 is further arranged on the fracturing pipe 1 through another annular groove; the second baffle ring 14 is an elastic baffle ring structure; the front end of the fracturing sleeve 2 is conical, and the fracturing sleeve 2 can expand the second retaining ring 14 by utilizing the conical structure at the front end under the action of external force so as to move from one side of the second retaining ring 14 to the other side. The inner hole of the first baffle ring 15 is in a taper hole shape, so that the taper hole is matched with an outer cone at the front end of the fracturing sleeve 2, the supporting strength of the fracturing sleeve 2 to the dissoluble fracturing ball 7 is enhanced, and the fracturing bearing capacity is improved.
In this implementation, be equipped with the interim fixed pin 8 that two circumferences distribute on fracturing cover 2, interim fixed pin 8 adopts aluminum alloy split pin structure, and 8 one end of interim fixed pin are fixed on fracturing cover 2, and the other end is worn to establish in the sieve mesh 9 that the sieve pore pipe corresponds the position.
The device of the embodiment also comprises a grouting pipe 16, a slurry return pipe 17, a pressure gauge 18 and a one-way valve 19; the grouting pipe 16 is used for injecting cement paste when drilling and sealing holes; the slurry return pipe 17 is mainly used for returning slurry to an orifice during grouting and hole sealing and can also be used for secondary grouting; the pressure gauge 18 is used for monitoring the pressure in the hole in the whole process; the check valve 19 is arranged at the pipe orifice of the fracturing pipe 1, and the check valve 19 is used for fracturing and pressure maintaining; the inlet end of the one-way valve 19 forms a pipeline connecting interface 20, and the fracturing pipe 1 is connected with a fracturing pump or a fracturing pump set through a high-pressure pipeline through the pipeline connecting interface 20.
In this implementation, fracturing cover 2 is equipped with two, and the hole passageway of two fracturing cover 2 is outwards crescent by the hole inner end, and the dissoluble fracturing ball that sits on the fracturing cover 2 near the hole bottom can pass the hole passageway of that fracturing cover 2 near the drill way.
The fracturing set 2 may also be provided in three, four or more, depending on the fracturing stage design requirements. Similarly, a dissolvable fracturing ball seated on a fracturing sleeve 2 near the bottom of the hole can pass through the internal bore passage of the immediately adjacent fracturing sleeve 2 near the direction of the orifice.
The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (10)
1. The method is characterized by comprising the steps of hole sealing, fracturing and extraction; wherein, hole sealing is carried out according to a full-hole section grouting hole sealing mode under the condition that a protective film is wrapped outside the sieve holes; fracturing adopts a dissolvable fracturing ball pitching staged fracturing mode, fracturing fluid penetrating through a sieve mesh penetrates through a rubber sheet and a hole sealing section corresponding to a hole sealing part and then is communicated with a coal bed, and fracturing is carried out by replacing the fracturing fluid with a saline solution; the dissolvable fracturing ball is made of low-density resin materials, the specific gravity of the dissolvable fracturing ball is smaller than that of fracturing fluid, the dissolvable fracturing ball can be soaked and dissolved through salt solution, a fracturing sleeve in the fracturing device for fracturing is fixed by a temporary fixing pin which can be cut by fracturing pressure, and the dissolvable fracturing ball pushes the fracturing sleeve to move under the action of the fracturing fluid so as to cut the temporary fixing pin and expose a sieve pore.
2. The method of claim 1, wherein the salt solution is injected as a displacement fluid for the fracturing fluid after completion of all staged fracturing.
3. A method according to claim 1 or 2, characterized by the following steps:
the method comprises the following steps that firstly, a long drilling driller conducts directional long drilling of the coal seam along the coal seam trend in the coal seam, the drilling length is more than 200 meters, and the hole diameter is not less than 120 mm;
secondly, preparing fracturing, namely performing on-site preparation work of a hydraulic fracturing pump, a sand adding pump set, a high-pressure manifold, a staged packing and fracturing tool, fracturing fluid and fracturing sand according to fracturing construction requirements;
thirdly, determining a segmentation scheme, and designing the number of the directional long drill holes of the coal seam and the corresponding segment length according to the long drill hole forming data;
fourthly, preparing a fracturing device, preparing and forming the corresponding pipe section members of the fracturing device according to the segmentation quantity and the corresponding indexing length design result, and connecting the pipe section members into the fracturing device;
fifthly, placing a drilling hole dredging and fracturing device, after dredging a well, washing the well, and removing sediments in the hole, placing the main body part of the fracturing device into the drilling hole to a set position, exposing the orifice of a fracturing pipe of the fracturing device outside the drilling hole, and centralizing the fracturing pipe by using a centralizer and making the fracturing pipe concentric with the drilling hole;
sixthly, sealing and fixing the hole, namely injecting cement slurry from the grouting pipe until the slurry return pipe returns slurry, performing secondary grouting by using the slurry return pipe so as to fill the annular space between the fracturing device and the inner wall of the drilled hole with the cement slurry, and waiting for solidification;
seventhly, connecting the fracturing device with a fracturing pump, and connecting an exposed pipe orifice of the fracturing device with the fracturing pump through a high-pressure pipeline;
the eighth step, throwing ball for fracturing, throwing a dissolvable fracturing ball matched with the fracturing sleeve of the corresponding fracturing section into the fracturing pipe, starting a fracturing pump, and throwing the dissolvable fracturing ball to a ball seat part of the fracturing sleeve of the corresponding section by fracturing fluid according to a pressure value lower than the fracturing pressure so as to realize the sealing of the fracturing pipe and the fracturing section;
step nine, boosting pressure and fracturing, continuously injecting water and pressurizing to enable the pressure of the fracturing fluid to be raised to the range of the fracturing pressure, applying the fracturing pressure through a dissolvable fracturing ball, shearing off a corresponding temporary fixing pin to enable a fracturing sleeve to move so as to open a sieve pore, utilizing the fracturing fluid to penetrate through a protective rubber sheet, forming a jet flow channel communicated with a coal bed on a corresponding hole sealing section, and then performing anti-reflection fracturing on the coal bed of the fracturing section;
tenth step, judging whether the fracturing construction is finished or not, and judging whether a fracturing section which is not fractured exists in a fracturing section adjacent to the fracturing section; if yes, returning to the ninth step; if not, executing the next step;
step eleven, injecting a saline solution, and injecting the saline solution with a set proportion to replace fracturing fluid, wherein the saline solution is used for dissolving fracturing balls;
the twelfth step, maintaining the pressure, namely maintaining the pressure for a set time after injecting the saline solution with a set concentration and a set amount, so that after the fracturing balls are dissolved, all the fracturing sections can be communicated through a fracturing pipe;
and thirteenth, gas extraction, namely connecting the fracturing pipe of the fracturing device with an extraction pipeline, and performing gas extraction.
4. The method of claim 3, wherein the fracture pressure set point is 20MPa to 37 MPa.
5. The method of claim 3, wherein the frac pump consists of a single pump or a dual or multiple pumps in parallel to form a frac pump group.
6. The method of claim 5, wherein in the frac pump set protocol, only 1 of the frac pumps is activated when delivering the dissolvable frac ball.
7. The coal seam long-drill-hole staged fracturing and extraction device is characterized by comprising a fracturing pipe (1), wherein at least two sieve hole pipes with sieve holes (9) are connected to the fracturing pipe (1) in series, a fracturing sleeve (2) is matched in the sieve hole pipes in a sliding mode, a ball seat structure for accommodating a fracturing ball (7) capable of being dissolved is arranged on the fracturing sleeve (2), a first retaining ring (15) is arranged on the fracturing pipe (1) located at the inner end of the fracturing sleeve (2) through an annular groove, the first retaining ring (15) is used for limiting the position of the fracturing sleeve (2) during fracturing, and guide shoes (3) are connected to a pipe section, close to the bottom of a drill hole, of the fracturing pipe (1) in series; from the hole bottom of the drill hole to the hole opening, inner hole channels of the ball seat structure on the fracturing sleeve (2) are sequentially enlarged and can pass through a dissoluble fracturing ball (7) which is close to a fracturing section and faces the direction of the hole bottom; a pressure relief bypass (4) and a ball throwing bypass (11) are arranged at the end part of the fracturing pipe (1) exposed out of the drill hole, a pressure relief valve (5) is arranged on the pressure relief bypass (4), and an outlet end of the pressure relief bypass (4) is provided with a connector connected with a gas-water separator; the pressure relief bypass (4) is detachably connected with a gas-water separator (6) through the interface; the fracturing sleeve (2) is fixedly connected with the sieve hole pipe through a temporary fixing pin (8); the fracturing sleeve (2) can move along with the soluble fracturing ball (7) in the process that the fracturing fluid pushes the soluble fracturing ball (7) so as to shear the temporary fixing pin (8) and open the sieve hole (9); the outside of the sieve pore (9) is wrapped with a sieve pore protective film (10); and a ball throwing valve (12) is arranged on the ball throwing bypass (11).
8. The device according to claim 7, characterized in that a centralizer (13) is arranged between the fracturing pipe (1) and the inner wall of the borehole, the centralizer (13) being close to the orifice of the borehole.
9. The device according to claim 7, characterized in that the fracturing pipe (1) is also provided with a second stop ring (14) by means of another annular groove; the second baffle ring (14) is in an elastic baffle ring structure; the front end of the fracturing sleeve (2) is conical, and the fracturing sleeve (2) can expand the second retaining ring (14) by utilizing the conical structure at the front end under the action of external force so as to move from one side of the second retaining ring (14) to the other side.
10. The device according to claim 9, characterized in that the inner bore of the first retaining ring (15) is in the form of a tapered bore, which is in a tapered fit with the outer taper of the fracturing sleeve (2).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011007065.0A CN112127854A (en) | 2020-09-22 | 2020-09-22 | Staged fracturing and extraction method for long drill hole of coal seam and pressure-extraction integrated device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011007065.0A CN112127854A (en) | 2020-09-22 | 2020-09-22 | Staged fracturing and extraction method for long drill hole of coal seam and pressure-extraction integrated device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112127854A true CN112127854A (en) | 2020-12-25 |
Family
ID=73842677
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011007065.0A Pending CN112127854A (en) | 2020-09-22 | 2020-09-22 | Staged fracturing and extraction method for long drill hole of coal seam and pressure-extraction integrated device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112127854A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113494264A (en) * | 2021-07-09 | 2021-10-12 | 中煤科工集团西安研究院有限公司 | Water-resisting layer reinforced grouting transformation device and method based on staged fracturing |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203271702U (en) * | 2013-03-26 | 2013-11-06 | 重庆松藻煤电有限责任公司 | Fracturing pipe in down hole hydraulic fracturing high-pressure seal hole |
| US8757265B1 (en) * | 2013-03-12 | 2014-06-24 | EirCan Downhole Technologies, LLC | Frac valve |
| CN104453778A (en) * | 2014-11-06 | 2015-03-25 | 中国石油天然气股份有限公司 | Fracture sliding sleeve with dissoluble ball seat and fracturing method |
| CN105156067A (en) * | 2015-10-09 | 2015-12-16 | 中煤科工集团重庆研究院有限公司 | Coal mine underground hydraulic fracturing drill hole sealing device and method |
| CN105201480A (en) * | 2015-10-14 | 2015-12-30 | 山西晋煤集团技术研究院有限责任公司 | Surface well-underground long borehole coal bed fracturing method |
| CN108643877A (en) * | 2018-05-21 | 2018-10-12 | 中国矿业大学 | Coal mine underground coal bed long drilled holes staged fracturing is anti-reflection and mash gas extraction method |
| CN111425178A (en) * | 2020-05-08 | 2020-07-17 | 重庆市能源投资集团科技有限责任公司 | Coal mine underground branch drilling staged fracturing permeability increasing method and pressure pumping integrated device |
-
2020
- 2020-09-22 CN CN202011007065.0A patent/CN112127854A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8757265B1 (en) * | 2013-03-12 | 2014-06-24 | EirCan Downhole Technologies, LLC | Frac valve |
| CN203271702U (en) * | 2013-03-26 | 2013-11-06 | 重庆松藻煤电有限责任公司 | Fracturing pipe in down hole hydraulic fracturing high-pressure seal hole |
| CN104453778A (en) * | 2014-11-06 | 2015-03-25 | 中国石油天然气股份有限公司 | Fracture sliding sleeve with dissoluble ball seat and fracturing method |
| CN105156067A (en) * | 2015-10-09 | 2015-12-16 | 中煤科工集团重庆研究院有限公司 | Coal mine underground hydraulic fracturing drill hole sealing device and method |
| CN105201480A (en) * | 2015-10-14 | 2015-12-30 | 山西晋煤集团技术研究院有限责任公司 | Surface well-underground long borehole coal bed fracturing method |
| CN108643877A (en) * | 2018-05-21 | 2018-10-12 | 中国矿业大学 | Coal mine underground coal bed long drilled holes staged fracturing is anti-reflection and mash gas extraction method |
| CN111425178A (en) * | 2020-05-08 | 2020-07-17 | 重庆市能源投资集团科技有限责任公司 | Coal mine underground branch drilling staged fracturing permeability increasing method and pressure pumping integrated device |
Non-Patent Citations (1)
| Title |
|---|
| 董国福等: "水力压裂增透技术在煤巷掘进中的应用", 《华北科技学院学报》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113494264A (en) * | 2021-07-09 | 2021-10-12 | 中煤科工集团西安研究院有限公司 | Water-resisting layer reinforced grouting transformation device and method based on staged fracturing |
| CN113494264B (en) * | 2021-07-09 | 2023-07-07 | 中煤科工集团西安研究院有限公司 | Waterproof layer reinforced grouting reconstruction device and method based on segmented fracturing |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108643877B (en) | Coal mine underground coal seam long drilling staged fracturing permeability-increasing and gas extraction method | |
| CN101915083B (en) | Method for extracting coalbed gases from coal mines by upper and lower combination | |
| CN105332684B (en) | A kind of water under high pressure is quick-fried and CO2The coal bed gas displacement extraction technique that pressure break is combined | |
| CN108757000A (en) | A kind of quick slot orientation fracturing system in underground based on drilling machine power and method | |
| CN101614135B (en) | Drilling-explosion-pumping triadic gas extraction method | |
| CN110953015B (en) | Soft low-permeability coal seam long-drill-hole directional segmented fracturing efficient gas extraction method | |
| CN103195468A (en) | System process for conducting efficient strengthened extraction in surrounding rock | |
| CN108547604B (en) | Drilling and stamping integrated device and method | |
| WO2019205516A1 (en) | System for extracting gas from tectonically-deformed coal seam in-situ by depressurizing horizontal well cavity | |
| CN108678802A (en) | A kind of coal mine bores, punching, takes out integrated outburst prevention device and method | |
| CN102704905A (en) | Segmental hydraulic fracturing coal seam pressure releasing device and method | |
| WO2019205515A1 (en) | Method of extracting gas from tectonically-deformed coal seam in-situ by depressurizing horizontal well cavity | |
| CN103939077A (en) | Perforation fracturing permeability-improvement method for high-stress low-porosity coal seam | |
| CN102080519A (en) | Method for extracting coal bed gas by negative pressure on ground through gas-coal simultaneous extraction | |
| CN113250670B (en) | Single-hole multi-section synchronous control fracturing coal body permeability increasing system and method | |
| CN102261261B (en) | Drilling and reflection reducing integrated device for tectonic coal development area | |
| CN103161493A (en) | Gas-liquid-solid three-phase coupling blasting weakening rock burst and permeability increasing method | |
| CN102434192A (en) | Device and method for enhancing coal seam fracturing effect | |
| CN112127854A (en) | Staged fracturing and extraction method for long drill hole of coal seam and pressure-extraction integrated device | |
| CN112593912B (en) | Coal bed gas horizontal well power expanding, pressure relief and permeability increase extraction method | |
| CN110410053A (en) | Coal mine roof plate pressure relief method based on eyelet supporting | |
| CN112343570A (en) | Coal mine porous hydraulic fracturing system and control method | |
| CN114961680B (en) | Near-coal-seam roof directional perforation-fracturing integrated device and use method thereof | |
| CN111425178A (en) | Coal mine underground branch drilling staged fracturing permeability increasing method and pressure pumping integrated device | |
| CN113494264B (en) | Waterproof layer reinforced grouting reconstruction device and method based on segmented fracturing |
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 | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20201225 |
|
| RJ01 | Rejection of invention patent application after publication |