CN112593912B - Coal bed gas horizontal well power expanding, pressure relief and permeability increase extraction method - Google Patents
Coal bed gas horizontal well power expanding, pressure relief and permeability increase extraction method Download PDFInfo
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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 DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B29/00—Cutting or destroying pipes, packers, plugs, or wire lines, located in boreholes or wells, e.g. cutting of damaged pipes, of windows; Deforming of pipes in boreholes or wells; Reconditioning of well casings while in the ground
- E21B29/06—Cutting windows, e.g. directional window cutters for whipstock operations
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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 DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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 DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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 DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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
- E21B43/30—Specific pattern of wells, e.g. optimizing the spacing of wells
- E21B43/305—Specific pattern of wells, e.g. optimizing the spacing of wells comprising at least one inclined or horizontal well
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B7/00—Special methods or apparatus for drilling
- E21B7/04—Directional drilling
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B7/00—Special methods or apparatus for drilling
- E21B7/04—Directional drilling
- E21B7/046—Directional drilling horizontal drilling
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B7/00—Special methods or apparatus for drilling
- E21B7/20—Driving or forcing casings or pipes into boreholes, e.g. sinking; Simultaneously drilling and casing boreholes
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B7/00—Special methods or apparatus for drilling
- E21B7/28—Enlarging drilled holes, e.g. by counterboring
Abstract
A coal bed gas horizontal well power expanding, pressure relieving and permeability increasing extraction method belongs to the field of mine gas treatment and coal bed gas co-extraction, can solve the problems that the underground coal extraction work amount of the extraction of broken soft low-permeability coal bed gas is large, the cost is high, and potential safety hazards exist in the underground gas extraction, a ground horizontal well is arranged in a mine preparation area and an exploitation preparation area along the direction of a recovery working face for gas pre-extraction, a three-opening well body structure is mined out in the horizontal well, a steel sleeve or a glass steel sleeve is arranged under a three-opening open hole completion, high-pressure air power expanding and pressure relieving are carried out on the horizontal section, the expanding position and the number are determined according to an expanding process, the air power expanding method is adopted for pressure relief of a coal bed, the stress of the coal bed is released, methane in the coal bed is rapidly desorbed, the productivity of the ground coal bed gas well is improved, and the continuous high yield of the coal bed gas is ensured. The underground bottom suction roadway is gradually replaced, the underground gas pre-suction time is shortened, the potential safety hazard of underground gas outburst is eliminated, and the risk of gas overrun and the coal mining cost are reduced.
Description
Technical Field
The invention belongs to the technical field of mine gas treatment and coal bed gas co-extraction, and particularly relates to a coal bed gas horizontal well power diameter-expanding pressure-relief anti-reflection extraction method.
Background
The broken soft low-permeability coal bed has poor air permeability and strong gas adsorption capacity to the coal bed due to complex structure, brittle quality and ultralow permeability, and the technical problem of how to efficiently extract the gas in the broken soft low-permeability coal bed is always the extraction of the coal bed gas in the broken soft low-permeability coal bed. The ground extraction difficulty of the broken soft low-permeability coal bed gas is large, the extraction efficiency is low, the time is long, the cost is high, the broken soft low-permeability coal bed is always regarded as a forbidden area for the ground coal bed gas extraction, the total single well yield of the fracturing vertical well is low, the stable production period is short, the attenuation is fast, the extraction rate is low, the extraction technology is not broken through, and the broken soft low-permeability coal bed gas is a technical bottleneck which restricts the coal mine gas disaster prevention and control work and the coal bed gas industrialization development of China for many years.
The broken soft low-permeability coal seam in China is widely distributed, and the common pre-pumping method for the high-gas mine is a coal mine underground coal-drawing pressure-relief permeability-increasing technology at present. The technology for releasing pressure and increasing permeability of broken soft low-permeability high-gas mine underground coal drawing comprises a technology for drawing coal to release pressure by exploiting a protective layer formed by exploiting a thin coal layer or a soft rock layer (called as a protective layer) overlying or underlying a main mining coal layer, a technology for actively promoting high-pressure hydraulic cutting of coal walls of underground roadways or working faces of coal mines by using Zhaoyang and Hokkaido and a Lixiahong academy, and a technology for actively exploring the pressure release and coal drawing of underground gas drawing holes of coal mines by units such as a Jinyang and Hokkaido and a Lixiahong academy. The three underground coal drawing technologies have good pressure relief effect, but have large engineering quantity and high cost, and certain potential safety hazards exist in underground gas extraction.
Therefore, an economical and efficient ground coal digging and pressure relief technology is urgently needed to be researched to replace underground coal digging and gas pre-pumping, the potential safety hazard of underground gas overrun is effectively eliminated, and the commercial exploitation of broken soft low-permeability coal bed gas is realized.
Disclosure of Invention
The invention provides a coal bed gas horizontal well power expanding, pressure releasing and permeability increasing extraction method, aiming at the problems that the underground coal extraction engineering quantity of the broken soft low-permeability coal bed gas is large, the cost is high, and certain potential safety hazards exist in underground gas extraction.
The invention provides a coal bed gas horizontal well power diameter expanding pressure relief anti-reflection extraction technology, and particularly relates to a broken soft low-permeability coal bed gas extraction technology. The method comprises the steps of arranging ground horizontal wells along the direction of a stope face in a mine preparation area and an exploitation preparation area for gas pre-pumping, hollowing out a three-opening well body structure in the horizontal wells, putting steel sleeves or glass steel sleeves in a three-opening open-hole well completion, carrying out high-pressure air power expanding pressure relief on the horizontal section, determining expanding positions and quantity according to an expanding process, and relieving pressure of a coal bed by adopting an air power expanding method so as to release the stress of the coal bed, rapidly desorb methane in the coal bed, improve the productivity of the ground coal bed gas well and ensure the continuous high yield of the coal bed gas. The underground bottom suction roadway is gradually replaced, underground gas pre-suction time is shortened, the potential safety hazard of underground gas outburst is eliminated, the risk of gas overrun and the coal mining cost are reduced, and safe, high-yield and high-efficiency coal mine production is finally realized.
The invention adopts the following technical scheme:
a coal bed gas horizontal well power expanding, pressure relief and permeability increase extraction method comprises the following steps:
step one, a drainage and production well drilling completion project: selecting three drainage and mining methods according to the dip angle of the coal seam and the ground condition: adopting an engineering well drainage and production, a near-end butt joint well drainage and production or a far-end butt joint well drainage and production;
step two, horizontal well drilling engineering: a hole with the diameter of 444.5mm is drilled to be 10m below the stable bedrock, a surface casing pipe with the diameter of 339.7mm is put in, and the well cementation returns to the hole opening; secondly, opening a hole with the diameter of 311mm to be 5m above the coal seam roof, putting a 244.5mm technical casing into the hole, and cementing the well and returning to the hole opening; the diameter of the three-opening hole is 215.9mm to the position of a final hole;
thirdly, horizontal segment butt joint: when in butt joint, an EM-MWD instrument is used for the horizontal well, an RMRS instrument is used for the vertical well, and target point data calculated by the RMRS is the relative position calculated according to the bottom of the horizontal well;
fourthly, casing completion: three-opening cementing is not performed, and three-opening casing is completed by selecting a glass fiber reinforced plastic casing;
fifthly, discharging and plugging the production well: the plugging position is selected to be 1m above the butt joint position of the horizontal well;
sixthly, milling the casing pipe section: windowing the horizontal well section;
seventh step, well washing: flushing the fragments after milling the sections of the three-opening sleeve in the horizontal well, and flushing the fragments and coal powder in the well to the ground by utilizing a positive circulation well flushing mode of liquid outlet of a liquid inlet ring of the continuous oil pipe;
eighthly, mechanically expanding the diameter: expanding from 311mm to 500mm, and adopting foam slurry as circulating liquid;
ninth step, secondary well washing: flushing the fragments and coal powder in the well after mechanical diameter expansion to the ground by using a positive circulation well flushing mode of liquid outlet of the liquid inlet annulus of the continuous oil pipe;
tenth step, power expanding: adopting a reverse mode, carrying out high-pressure air power expanding one by one, carrying out power expanding by using a high-pressure air medium, and returning pulverized coal to the ground in the blowout process;
step eleven, pressure building and open flow: closing the well and holding the pressure for 5min, after the pressure is stabilized, opening a ground blowout valve instantly, starting pressure relief and blowout to ensure that a coal bed near the well hole is damaged and collapsed, ejecting coal briquettes, rock debris and desorbed coal bed gas which is vibrated by pressure out of the well along with atomized air or atomized nitrogen, allowing the coal briquettes and the rock debris to enter a coal briquette collecting tank along with a transportation pipeline, opening a blowout preventer valve after blowout, closing a ground blowout manifold, and starting to circulate the coal dust in the well by using air until the coal dust does not return obviously, wherein the period is 1 power expanding period;
the tenth step and the eleventh step are continuously circulated in the 2 nd power expanding process until the coal powder return amount is very small under the same pressure, the gas injection pressure is gradually increased until no coal powder returns obviously, and the next power expanding coal-digging period is prepared after the preset coal-digging amount is reached;
step eleven, pore diameter filling: selecting a filling material with rich hole cracks for supporting the hole diameter to prevent cave collapse, simultaneously facilitating the production of coal bed gas and water or selecting a soluble filling material, and injecting a corresponding solution to dissolve the filling material after dissolving the bridge plug;
step thirteen, sealing the pore diameter: after the first large aperture is finished, setting and sealing the formed large aperture by adopting a dissolvable bridge plug to form the next aperture;
and fourteenth, dissolving the bridge plug and the pore diameter: after all the apertures are manufactured according to the design, circulation is performed, corresponding dissolving liquid capable of dissolving the bridge plug is injected, and the 'soluble bridge plug' and the aperture fillers are dissolved in sequence;
a fifteenth step, well cleaning: carrying out well dredging and well washing on the horizontal well, selecting a continuous oil pipe to inject well washing liquid into the horizontal well, and carrying coal dust and rock debris in the well to the ground;
sixthly, removing the oil extraction well and unsealing: utilizing a drill bit to destroy a plugging bridge plug in the drainage and production well or salvage the salvage type bridge plug;
seventeenth step, discharging and fishing sand in the production well: carrying out ground sand bailing treatment on debris such as rock debris, coal dust and the like entering the drainage and production well;
eighteenth, arranging and mining equipment: the drainage and mining mode comprises positive pressure drainage and negative pressure drainage, and is selected according to the conditions in the well;
nineteenth step, drainage and mining: aiming at a power expanding, pressure relieving and anti-reflection horizontal well, a drainage and mining scheme is formulated, and a positive pressure extraction and negative pressure extraction composite extraction method is adopted; simultaneously performing ground extraction at the two ends of the drainage and extraction well and the engineering well; and the engineering well is not provided with a drainage and extraction device, and the well mouth is directly merged into an air pipeline for extraction by utilizing a four-way device.
The selection method of the drainage and mining method in the first step is as follows: when the inclination angle of the target coal seam is larger, the target coal seam is an upward slope along the horizontal section direction of the horizontal well, and when the engineering well drilling meets the coal seam and is positioned at the relatively low end, the engineering well is selected for drainage and mining or the near-end butt-joint well is selected for drainage and mining; the target coal seam is in a downhill slope along the horizontal section direction of the horizontal well, and when the drainage and production well drill is positioned at the relatively low end of the coal seam, the far-end butt well is utilized for drainage and production.
In the first step, the structure of the drainage and production well body is as follows: drilling a hole with the diameter of 311mm to 10m below bedrock, putting a 244.5mm technical casing, and cementing and returning to the hole opening; and the diameter of the second opening is 215.9mm, drilling is finished until the diameter is 30m below a target coal seam, a production casing pipe with the diameter of 139.7mm is put in, and well cementation is carried out.
And in the third step, the horizontal section is in butt joint with the whole-root recorded data of the well section of 70m-40m, the half-root recorded data of the well section of 40m-20m and the recorded data of 3 meters of the well section from 20m to the last.
The diameter of the glass fiber reinforced plastic sleeve in the fourth step is 177.8mm or 139.7 mm.
In the fifth step, the plugging material comprises a drillable bridge plug or a salvageable bridge plug.
And in the sixth step, the distance between the windows is 25-50 m.
The gas displacement of the high-pressure air medium in the tenth step is more than 90m3Min, and the output pressure is more than 2 MPa.
The method for selecting the drainage and mining mode in the eighteenth step comprises the following steps: water exists in the well at the early stage, drainage and production are carried out by adopting a drainage and depressurization mode, and the method comprises two schemes of a sucker-rod pump and a rodless pump; in the later period of drainage and extraction, in order to quickly extract coal bed gas, a water ring vacuum pump is used for negative pressure extraction; wherein the rod pump comprises a tubular pump, a screw pump, an electric submersible pump and a jet pump; the rodless pump includes a submersible diaphragm pump.
The invention has the following beneficial effects:
according to the invention, ground horizontal wells are arranged in the mine preparation area and the exploitation preparation area along the direction of a stope face for gas pre-pumping, the horizontal wells are exploited to form a three-opening well body structure, steel sleeves or glass steel sleeves are arranged in the three-opening well completion, the horizontal section is subjected to subsection power cave making and coal digging according to the cave making process to determine the cave making positions and the quantity, and the air power cave making method is adopted to relieve the pressure of the coal bed, so that the stress of the coal bed is released, the methane in the coal bed is quickly desorbed, the productivity of ground coal bed gas wells is improved, and the continuous high yield of the coal bed gas is ensured.
The invention achieves the following effects: the purpose of efficiently and quickly pumping the coal bed gas by the ground well of the broken soft low-permeability coal mine is achieved through the implementation of the scheme, the pre-pumping time of the coal bed gas is shortened, and the continuous high yield of the ground well is realized. The underground gas pre-pumping tunnel is gradually replaced, underground gas pre-pumping time is shortened, the potential safety hazard of underground gas outburst is eliminated, the risk of gas overrun and the coal mining cost are reduced, and the safe, high-yield and high-efficiency production of the broken soft low-permeability coal mine is finally realized.
Drawings
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is a schematic structural view of a horizontal shaft of a coal bed methane ground coal extraction well according to the present invention;
FIG. 3 is a schematic diagram of a horizontal well drainage scheme for coal bed methane ground coal extraction according to the present invention;
wherein: 1-one opening; 2-deflecting point; 3-opening for two times; 4-a landing site; 5-coal bed; 6-three opening; 7-pressure relief holes; 8-drainage and production of the engineering well; 9-near end butt joint well drainage and production; and 10-remote end butting well drainage.
Detailed Description
1) And (3) well drilling and completion engineering of drainage and production wells:
the drainage and mining method is preferably as follows: according to the dip angle of the coal seam and the concrete condition of the ground, three drainage and mining methods are selected: and (4) adopting an engineering well drainage and production, a near-end butt joint well drainage and production and a far-end butt joint well drainage and production. When the inclination angle of the target coal seam is larger, the target coal seam is an upward slope along the horizontal section direction of the horizontal well, and when the engineering well drilling is in a relatively low end in the coal seam, the engineering well can be selected for drainage and mining or a near-end butt well can be selected for drainage and mining; the target coal seam is downhill along the horizontal section direction of the horizontal well, and when the drainage and production well drill is positioned at the relatively low end of the coal seam, a far-end butt well can be utilized for drainage and production.
The well body structure of the drainage and production well: and (3) drilling a hole with the diameter of 311mm to 10m below the bedrock, putting a 244.5mm technical casing, and cementing and returning to the hole opening. And the diameter of the second opening is 215.9mm, drilling is finished until the diameter is 30m below a target coal seam, a production casing pipe with the diameter of 139.7mm is put in, and well cementation is carried out.
2) Horizontal well drilling engineering: and (3) opening the hole with the diameter of 444.5mm to be 10m below the stable bedrock, setting an 339.7mm surface casing pipe, and cementing and returning to the hole opening. And the hole diameter of the second opening is 311mm, the hole diameter is 5m above the coal seam roof, a 244.5mm technical casing is put in, and the well cementation returns to the hole opening. The diameter of the three-opening hole is 215.9mm, and the position of the final hole is reached.
3) Butt joint of horizontal sections: the horizontal communication well is a corresponding vertical well drilled through by the horizontal well, the horizontal well mainly comprises coal seam geosteering and final target point butt joint, an EM-MWD instrument is used for the horizontal well during butt joint, and an RMRS instrument is used for the vertical well. The target point data calculated by RMRS is the relative position calculated according to the bottom of the horizontal well. Generally, data are recorded once for the whole well section of 70m-40m, once for the half well section of 40m-20m and data are recorded for 3 m from 20m to the last well section. If a special is encountered, the recorded data may be encrypted.
4) Casing completion: three-opening cementing is not performed, in order to reduce the workload of cutting a steel sleeve and the potential safety hazard of underground cutting of a casing pipe during later coal mining, the three-opening casing pipe is completed by selecting a glass steel sleeve pipe, and the specification of the glass steel sleeve pipe is 177.8mm or 139.7 mm.
5) Plugging a drainage and production well: in order to ensure smooth cave building of the horizontal section, the drainage and production well is plugged, the plugging position is 1m above the butt joint position of the horizontal well, and plugging materials can be selected from drillable bridge plugs or salvageable bridge plugs.
6) Milling the casing section: and windowing is carried out at a certain interval in the horizontal well section, the interval can be selected from 25-50m, and the windowing number is determined according to factors such as coal extraction quantity, coal reservoir permeability and the like.
7) Well flushing: and flushing the fragments after milling the sections of the three-opening sleeve in the horizontal well, and flushing the fragments and coal powder in the well to the ground by utilizing a positive circulation well flushing mode of liquid outlet of a liquid inlet ring of the continuous oil pipe.
8) Mechanical expanding: expanding from 311mm to 500 mm; foam slurry is used as circulating liquid.
9) And (3) secondary well flushing: and the well washing mode of positive circulation of liquid outlet of the liquid inlet annulus of the continuous oil pipe is utilized again, and the fragments and the coal powder in the well after the mechanical diameter expansion are washed to the ground.
10) Power expanding: by backward type, high-pressure air is carried out one by oneAnd expanding the power. The high-pressure air medium is used for power expanding, and the pulverized coal is returned to the ground in the open-flow process. The required gas displacement is more than 90m3Min, and the output pressure is more than 2 MPa.
11) Pressure building and open flow: and (3) closing the well and stopping pressure for 5min, instantly opening a ground blowout valve after the pressure is stable, starting pressure relief and blowout to ensure that the coal bed near the well hole is damaged to a certain extent and collapsed, and spraying the coal blocks, the rock debris and the coal bed gas desorbed by the coal blocks and the rock debris under the pressure vibration out of the well along with atomized air or atomized nitrogen. The coal blocks and the rock debris enter a coal block collecting tank along with a transportation pipeline. And after blowout, opening a valve of the blowout preventer, and closing the ground blowout manifold. And (3) starting to circulate the coal dust in the well by using air until the coal dust is not obviously returned, wherein the number of the coal dust is 1 power expanding period.
And (3) continuously circulating the steps 10 and 11 in the 2 nd power expanding process until the coal powder return amount is very small under the same pressure, and gradually increasing the gas injection pressure until no coal powder returns obviously. And after the preset coal drawing amount is reached, preparing the next power expanding coal drawing period.
12) And (3) filling the aperture: the filling material with abundant hole cracks is selected for supporting the hole diameter to prevent cave collapse, and meanwhile, the output of coal bed gas and water is facilitated. Alternatively, a soluble filler material can be chosen, and the filler can be dissolved away by injecting a corresponding dissolving liquid after the bridge plug is dissolved.
13) Pore diameter sealing: after the first large aperture is finished, setting and sealing the formed large aperture by adopting a dissolvable bridge plug to form the next aperture.
14) Dissolving the bridge plug and the pore diameter: after all the apertures are manufactured according to the design, circulation is performed, corresponding dissolving liquid capable of dissolving the bridge plug is injected, and the 'soluble bridge plug' and the aperture fillers are dissolved in sequence.
15) Well cleaning: and (4) dredging and washing the horizontal well, injecting the washing liquid into the horizontal well by selecting a continuous oil pipe, and carrying the coal dust and the rock debris in the well to the ground.
16) And (3) deblocking the drainage and production well: and (4) damaging the plugging bridge plug in the drainage and production well by using the drill bit, and fishing if the plugging bridge plug is a salvageable bridge plug.
17) And (3) discharging and extracting well sand: and carrying out ground sand pumping treatment on debris such as rock debris, coal dust and the like entering the drainage and production well.
18) Arranging and mining equipment: the drainage and mining modes are divided into positive pressure drainage and negative pressure drainage. In the early stage, if water exists in a well, drainage and production are carried out by adopting a drainage and depressurization mode, and the drainage and production method comprises two schemes of a sucker-rod pump (comprising a tubular pump, a screw pump, an electric submersible pump, a jet pump and the like) and a rodless pump (an oil-submersible diaphragm pump and the like). In the later stage of drainage and mining, in order to quickly extract coal bed gas, a water ring vacuum pump can be used for negative pressure extraction.
19) Drainage and mining: and (3) aiming at the power expanding, pressure relieving and anti-reflection horizontal well, a proper drainage and mining scheme is formulated, and a positive pressure extraction and negative pressure extraction composite extraction method can be adopted. And the drainage and production well and the engineering well can simultaneously perform ground drainage at two ends. The engineering well mouth does not need to be provided with drainage and extraction equipment, and the well mouth is directly merged into an air pipeline for drainage by utilizing a four-way device.
Claims (9)
1. A coal bed gas horizontal well power expanding, pressure relief and permeability increase extraction method is characterized by comprising the following steps: the method comprises the following steps:
step one, a drainage and production well drilling completion project: selecting three drainage and mining methods according to the dip angle of the coal seam and the ground condition: adopting an engineering well drainage and production, a near-end butt joint well drainage and production or a far-end butt joint well drainage and production;
step two, horizontal well drilling engineering: a hole with the diameter of 444.5mm is drilled to be 10m below the stable bedrock, a surface casing with the diameter of 339.7mm is put in, and the well cementation returns to the hole opening; secondly, opening a hole with the diameter of 311mm to be 5m above the coal seam roof, putting a 244.5mm technical casing into the hole, and cementing the well and returning to the hole opening; the diameter of the three-opening hole is 215.9mm to the position of a final hole;
thirdly, horizontal segment butt joint: when in butt joint, an EM-MWD instrument is used for the horizontal well, an RMRS instrument is used for the vertical well, and target point data calculated by the RMRS is the relative position calculated according to the bottom of the horizontal well;
fourthly, casing completion: three-opening cementing is not performed, and three-opening casing is completed by selecting a glass fiber reinforced plastic casing;
fifthly, discharging and plugging the production well: the plugging position is selected to be 1m above the butt joint position of the horizontal well;
sixthly, milling the casing pipe section: windowing the horizontal well section;
seventh step, well washing: flushing the fragments after milling the sections of the three-opening sleeve in the horizontal well, and flushing the fragments and coal powder in the well to the ground by utilizing a positive circulation well flushing mode of liquid outlet of a liquid inlet ring of the continuous oil pipe;
eighthly, mechanically expanding the diameter: expanding from 311mm to 500mm, and adopting foam slurry as circulating liquid;
ninth, secondary well washing: flushing the fragments and coal powder in the well after mechanical diameter expansion to the ground by using a positive circulation well flushing mode of liquid outlet of the liquid inlet annulus of the continuous oil pipe;
tenth step, power expanding: adopting a backward mode, carrying out high-pressure air power expanding one by one, carrying out power expanding by utilizing a high-pressure air medium, and returning the pulverized coal to the ground in the blowout process;
step eleven, pressure building and open flow: closing the well and holding the pressure for 5min, after the pressure is stabilized, opening a ground blowout valve instantly, starting pressure relief and blowout to ensure that a coal bed near the well hole is damaged and collapsed, ejecting coal briquettes, rock debris and desorbed coal bed gas which is vibrated by pressure out of the well along with atomized air or atomized nitrogen, allowing the coal briquettes and the rock debris to enter a coal briquette collecting tank along with a transportation pipeline, opening a blowout preventer valve after blowout, closing a ground blowout manifold, and starting to circulate the coal dust in the well by using air until the coal dust does not return obviously, wherein the period is 1 power expanding period;
the tenth step and the eleventh step are continuously circulated in the 2 nd power expanding process until the coal powder return amount is very small under the same pressure, the gas injection pressure is gradually increased until no coal powder returns obviously, and the next power expanding coal-digging period is prepared after the preset coal-digging amount is reached;
step eleven, pore diameter filling: selecting a filling material with rich hole cracks for supporting the hole diameter to prevent cave collapse, simultaneously facilitating the production of coal bed gas and water or selecting a soluble filling material, and injecting a corresponding solution to dissolve the filling material after dissolving the bridge plug;
step thirteen, sealing the pore diameter: after the first large aperture is finished, setting and sealing the formed large aperture by adopting a dissolvable bridge plug to form the next aperture;
and fourteenth, dissolving the bridge plug and the pore diameter: after all the apertures are manufactured according to the design, circulation is performed, corresponding dissolving liquid capable of dissolving the bridge plug is injected, and the 'soluble bridge plug' and the aperture fillers are dissolved in sequence;
a fifteenth step, well flushing: carrying out well dredging and well washing on the horizontal well, selecting a continuous oil pipe to inject well washing liquid into the horizontal well, and carrying coal dust and rock debris in the well to the ground;
sixthly, removing the oil extraction well and unsealing: utilizing a drill bit to destroy a plugging bridge plug in the drainage and production well or salvage the salvage type bridge plug;
seventeenth step, discharging and fishing sand in the production well: carrying out ground sand pumping treatment on debris such as rock debris, coal dust and the like entering the drainage and production well;
eighteenth, arranging and mining equipment: the drainage and mining mode comprises positive pressure drainage and negative pressure drainage, and is selected according to the conditions in the well;
nineteenth step, drainage and mining: aiming at a power expanding, pressure relieving and anti-reflection horizontal well, a drainage and mining scheme is formulated, and a positive pressure extraction and negative pressure extraction composite extraction method is adopted; simultaneously performing ground extraction at the two ends of the drainage and production well and the engineering well; and the engineering well is not provided with a drainage and extraction device, and the well mouth is directly merged into an air pipeline for extraction by utilizing a four-way device.
2. The coal bed gas horizontal well power diameter expanding, pressure relieving and permeability increasing extraction method according to claim 1, characterized by comprising the following steps: the selection method of the drainage and mining method in the first step is as follows: when the inclination angle of the target coal seam is larger, the target coal seam is an upward slope along the horizontal section direction of the horizontal well, and when the engineering well drilling meets the coal seam and is positioned at the relatively low end, the engineering well is selected for drainage and mining or the near-end butt-joint well is selected for drainage and mining; the target coal seam is in a downhill slope along the horizontal section direction of the horizontal well, and when the drainage and production well drill is positioned at the relatively low end of the coal seam, the far-end butt well is utilized for drainage and production.
3. The coal bed gas horizontal well power diameter expanding, pressure relieving and permeability increasing extraction method according to claim 1, characterized by comprising the following steps: in the first step, the structure of the drainage and production well body is as follows: drilling a hole with the diameter of 311mm to 10m below bedrock, putting a 244.5mm technical casing, and cementing and returning to the hole opening; and the diameter of the second opening is 215.9mm, drilling is finished until the diameter is 30m below a target coal seam, a production casing pipe with the diameter of 139.7mm is put in, and well cementation is carried out.
4. The coal bed gas horizontal well power expanding, pressure relieving and permeability increasing extraction method according to claim 1, characterized by comprising the following steps: and in the third step, the horizontal section is in butt joint with the whole-root recorded data of the well section of 70m-40m, the half-root recorded data of the well section of 40m-20m and the recorded data of 3 meters of the well section from 20m to the last.
5. The coal bed gas horizontal well power diameter expanding, pressure relieving and permeability increasing extraction method according to claim 1, characterized by comprising the following steps: the diameter of the glass fiber reinforced plastic sleeve in the fourth step is 177.8mm or 139.7 mm.
6. The coal bed gas horizontal well power diameter expanding, pressure relieving and permeability increasing extraction method according to claim 1, characterized by comprising the following steps: and fifthly, the material used for plugging comprises a drillable bridge plug or a salvageable bridge plug.
7. The coal bed gas horizontal well power diameter expanding, pressure relieving and permeability increasing extraction method according to claim 1, characterized by comprising the following steps: and in the sixth step, the distance between the windows is 25-50 m.
8. The coal bed gas horizontal well power diameter expanding, pressure relieving and permeability increasing extraction method according to claim 1, characterized by comprising the following steps: the gas displacement of the high-pressure air medium in the tenth step is more than 90m3Min, and the output pressure is more than 2 MPa.
9. The coal bed gas horizontal well power diameter expanding, pressure relieving and permeability increasing extraction method according to claim 1, characterized by comprising the following steps: the selection method of the drainage and mining mode in the eighteenth step is as follows: water exists in the well at the early stage, drainage and production are carried out by adopting a drainage and depressurization mode, and the method comprises two schemes of a sucker-rod pump and a rodless pump; in the later period of drainage and extraction, in order to quickly extract coal bed gas, a water ring vacuum pump is used for negative pressure extraction; wherein the rod pump comprises a tubular pump, a screw pump, an electric submersible pump and a jet pump; the rodless pump includes a submersible diaphragm pump.
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| CN114607319B (en) * | 2022-03-28 | 2024-04-05 | 贵州省油气勘查开发工程研究院 | Method for improving coalbed methane yield of multi-branch butt joint well by intermittent circulating liquid injection |
| CN117287177A (en) * | 2023-08-18 | 2023-12-26 | 甘肃靖远煤电股份有限公司魏家地煤矿 | Coal-bed gas well aerodynamic hole making method based on continuous pressure holding and releasing |
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