CN103883303A - Orientation jetting and fracturing exploitation method for coal bed gas under coal mine - Google Patents

Orientation jetting and fracturing exploitation method for coal bed gas under coal mine Download PDF

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Publication number
CN103883303A
CN103883303A CN201410163959.7A CN201410163959A CN103883303A CN 103883303 A CN103883303 A CN 103883303A CN 201410163959 A CN201410163959 A CN 201410163959A CN 103883303 A CN103883303 A CN 103883303A
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China
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coal
perforator
fracturing
pressure break
boring
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CN201410163959.7A
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Chinese (zh)
Inventor
李栋
郭臣业
覃乐
周东平
沈大富
周俊杰
张翠兰
张迪
向沉浅
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重庆市能源投资集团科技有限责任公司
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Priority to CN201410163959.7A priority Critical patent/CN103883303A/en
Publication of CN103883303A publication Critical patent/CN103883303A/en

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Abstract

The invention discloses an orientation jetting and fracturing exploitation method for coal bed gas under a coal mine. The method includes the steps that a drilled hole along a coal bed is formed in a top plate or a bottom plate; a fracturing pipe set and a radial perforator are placed in a first perforation position; the hole is sealed; the fracturing pump set and the perforator are connected with corresponding pump sets respectively, and a jet flow channel is formed by the perforator and used for communicating the coal bed and the drilled hole; annular fracturing liquid is injected into the drilled hole in a pressure mode, and meanwhile annular pressure is kept; the coal bed is continuously jetted for preset time so that cracks can be formed on coal bodies and extend in the bottom direction of jetting holes of the coal bed; jetting and fracturing are stopped at the same time, the perforator is moved to a next jetting position to form the jet flow channel, and then fracturing liquid is pressurize and jetted continuously; the steps of independently jetting a rock stratum and pressurizing and jetting the coal bed are repeatedly executed until jetting and fracturing at all positions in the drilled hole is finished, and then the coal bed gas is extracted. The orientation jetting and fracturing exploitation method has the advantages that the trend and the quantity of the cracks are controllable, exploitation efficiency of the coal bed is high, the gas disaster of the mine can be effectively prevented and treated, and economic and social benefits can be improved.

Description

A kind of method of vectored injection pressure break exploiting coal bed methane under coal mine

Technical field

The present invention relates to a kind of coal bed methane exploring method, the method for vectored injection pressure break exploiting coal bed methane under especially a kind of coal mine that is applicable to high gas low-permeable weak seam.

Background technology

Coal bed gas is a kind of energy of cleaning, but for coal production, is a kind of disaster source.How to realize the before efficient extraction coal bed gas of mining, reach the dual purpose of resources development and utilization and colliery mitigation, be the focus that people pay close attention to always.The method of the exploiting coal bed methane that now colliery down-hole application is more general is at present that after employing high-pressure hydraulic pressure break, the mode of extraction is exploited.The method is injected coal body by water under high pressure by boring, and coal body is pressed off to produce a large amount of cracks, reaches the object of efficient extraction coal bed gas.The defects such as press that to wear the required pressure of coal body high but the method exists, crack quantity and trend can not be controlled, and when the pressure break of multilayer position, need to carry out shutoff processing to the pressure break hole of fractured layer position, and engineering quantity is large therefore it exists, complex procedures, and the overall time of pressure break is long.Therefore, need badly and find a kind of high-pressure hydraulic pressure break controlled, efficient, simple to operate.

Summary of the invention

The object of the invention is the deficiency for existing Coal-seam Gas Recovery Technologies, the method of vectored injection pressure break exploiting coal bed methane under a kind of coal mine is provided, effectively to control crack quantity and trend, increase boring and coal seam contact area, improve coal-bed gas exploitation efficiency, the generation of control coal mine gas disaster, improves economic and social benefit.

For achieving the above object, the present invention adopts following technical scheme:

A method for vectored injection pressure break exploiting coal bed methane under coal mine, comprises the following steps:

A, in roof or base plate, form along the boring in coal seam, between the center of this boring and coal seam, there is setpoint distance h;

B, enter pressure break pipe group and for the perforator of perforation radially at this embedded in hole, and this perforator is placed to the first perforation position that need to carry out pressure break;

C, described boring is carried out to sealing of hole by pressure break seal request, form sealing of hole section with the orifice end in boring, this sealing of hole section forms static seal with pressure break pipe group, and with the feed tube formation movable sealing of perforator;

D, pressure break pipe group is connected with fracturing pump group by pipe fitting; The feed tube of perforator is connected with perforation pump group;

E, by perforation pump group, the perforation medium pump that contains abrasive material is delivered to described perforator, and form jetting stream by perforator, this jetting stream is penetrated and is worn the branched hole that formation coal seam, rock stratum is communicated with described boring;

F, inject fracturing fluid by fracturing pump group and pressure break Guan Zuxiang boring internal pressure;

G, by this branched hole, setting-up time is sprayed in coal seam by described perforator, and spray simultaneously and by fracturing pump group, the interior fracturing fluid of holing is pressurizeed, and keep pressure and control fracturing flow quantity, so that the coal body in coal seam forms the fracturing crack extending along direction at the bottom of the Perforation of coal seam;

H, close fracturing pump group, described perforator is moved to next pressure break position, and form next branched hole by perforation pump group and perforator; Return to step g until in whole boring the injection pressure break of each pressure break position complete;

I, dismounting perforator, will hole and be connected with coal mine gas extraction system, carry out coal bed gas extraction.

Adopt the present invention of technique scheme, in perforation process, first perforation pump group is pumped into jet media ejector and by the nozzle of ejector, high pressure potential energy converting and energy is become to kinetic energy, ejector produces high rapid fire stream cutting rock stratum, forms the branched hole with certain diameter and the degree of depth being communicated with coal seam.After branched hole perforation completes, ejector continues coal seam to spray to form coal seam perforation take this branched hole as fluidic channel, and expulsion pressure is now less than coal and rock fracture pressure, and coal seam does not crack; Now, inject fracturing fluid in rockhole after and by fracturing pump, pressurize, form the environment stress of ejector, in the technical program, be called annular pressure.During thering is annular pressure, the swabbing action that the high-pressure spray of ejector produces annular pressure liquid by fluidic channel, fracturing fluid is assembled in fluidic channel and coal seam perforation, form the stack of expulsion pressure and frac pressure, both pressure fracture pressures higher than coal rock layer that superpose, make coal rock layer produce crack, form and spray pressure break.Meanwhile, the percussion of high-velocity fluid can produce microcrack on the perforation top in coal seam, has reduced to a certain extent coal rock layer initial cracking pressure, thereby promotes coal seam cracking.The crack of this injection pressure break produces and extends on coal rock layer perforation top, therefore sprays pressure break and can effectively control crack initiation direction and fracture extension direction, thereby can realize the control fracturing being evenly distributed.Due to the swabbing action of ejector high-pressure spray, ring control fracturing fluid is constantly introduced in perforation tunnel and coal seam perforation, now, by control suitable annular space inject of the fracturing fluid flow in order to the leakage of compensation boring, maintain pressure, guarantee the lasting extension in crack.Can form on a large scale and can equally distributed Fracture Networks the final extraction efficiency object that effectively improves coal bed gas that realizes by the injection pressure break of multiple desired locations in boring.In addition, the swabbing action of ejector high-pressure spray also makes annular pressure be less than the just pressure in branched hole and the coal seam Perforation of ejection electrodes, also be less than initial cracking pressure and the fracture propagation pressure of coal and rock simultaneously, therefore, cracking can not continued in the coal body of pressure break position beyond spray god's pressure break position in spraying, do not need the position of ftractureing to seal, its naturally have dynamic seal every effect, do not need that the branched hole at position, pressure break coal seam is carried out to shutoff and just can avoid refracturing.The present invention is specially adapted to two coal seams that coal seam spacing is less and sprays pressure break, is penetrated and is worn rock stratum, both sides, and then two coalbed methane reservoirs are sprayed to pressure break simultaneously between two coal seams in boring by two or more nozzles of ejector.

In the present invention, annular fracturing flow quantity should be controlled according to situations such as bore leaking, fracture extension and droop loss.

Described branched hole also has the part that stretches into coal seam.Further to improve the guiding function of coal seam being sprayed to pressure break.

Preferably, the distance in described boring and coal seam is 0.5~1.0m.Boring should, according to selecting factors such as the perforation abilities of roof and floor lithologic and perforator, be determined with the steadiness principle high with spraying pressure break operating efficiency of guaranteeing to hole in injection fracturing process with the distance in coal seam.

Preferably, the diameter of described boring is more than or equal to 120mm.Fully to meet and to insert, take out pressure break pipe group and the needed space of perforator, easily collapse if geostatic stress, the tectonic stress etc. of General Requirements boring bore position are large or coal and rock is more broken, can cased hole completion.

The present invention's beneficial effect is compared with prior art that the present invention has guaranteed the stability of boring by drilling well in Seam Roof And Floor, avoided borehole collapse in coal seam; Pressure break direction, position and quantity are controlled, have guaranteed the connectedness in boring and coal seam; Reduce nearly boring area stress and concentrated, be conducive to improve nearly boring area permeability; Reduce coal seam fracture pressure, contribute to formation and the extension in crack; Perforation and pressure break connection are done, and have reduced workload; By annular pressure control, save the link that shutoff is carried out in the boring to pressing off layer position; Can directly successively carry out accurate perforating and fracturing to target zone position; Can construct in the random layer position that needs pressure break, the while is unrestricted for crack quantity, can effectively improve the extraction efficiency of coal bed gas.

Accompanying drawing explanation

Fig. 1 adopts the inventive method to carry out coal seam to spray the schematic diagram of pressure break.

The specific embodiment

Below in conjunction with accompanying drawing, the present invention is further illustrated, but therefore do not limit the present invention among described practical range.

Referring to Fig. 1, a kind of method of vectored injection pressure break exploiting coal bed methane under coal mine, comprises the following steps:

A, the boring 1 that formation is 120mm along coal seam and diameter in roof or base plate, between the center of this boring 1 and coal seam, having setpoint distance h is 0.5~1.0m;

B, in this boring 1, insert pressure break pipe group 2 and for the perforator 3 of perforation radially, and this perforator 3 is placed to the first perforation position that need to carry out pressure break;

C, described boring 1 is carried out to sealing of hole by pressure break seal request, form sealing of hole section 4 with the orifice end in boring 1, this sealing of hole section 4 forms static seal with pressure break pipe group 2, and forms movable sealing with the feed tube 31 of perforator 3;

D, pressure break pipe group 2 is connected with fracturing pump group 5 by pipe fitting; The feed tube of perforator 3 31 is connected with perforation pump group 6;

E, by perforation pump group 6, the perforation medium pump that contains abrasive material is delivered to described perforator 3, and form jetting stream by perforator 3, this jetting stream is penetrated and is worn the branched hole 8 that formation coal seam, rock stratum 7 is communicated with described boring 1, and this branched hole 8 has the part that stretches into coal seam 7, and this part forms coal seam perforation;

F, inject fracturing fluid by fracturing pump group 5 and pressure break pipe group 2 to boring 1 internal pressure, to form the annular fracturing liquid of ejector 3;

G, by this branched hole 8, setting-up time is sprayed in coal seam 7 by described perforator 3, and spray simultaneously and by fracturing pump group 5, the 1 interior fracturing fluid of holing is pressurizeed, annular fracturing liquid enters in branched hole 8 and coal seam perforation in the high-speed jet of perforator 3 under the pumping ejector action of branched hole 8 interior formation, and assemble in branched hole 8 and coal seam perforation, at the bottom of the hole of coal seam perforation, form the initial cracking pressure that pressure after annular space supercharging is greater than coal seam 7, so that cracking at the bottom of the Perforation of coal seam, keep pressure and control fracturing flow quantity, so that the coal body in coal seam 7 forms the fracturing crack extending along direction at the bottom of the Perforation of coal seam,

H, close fracturing pump group 5, described perforator 3 is moved to next pressure break position, and form next branched hole 8 by perforation pump group 6 and perforator 3; Return to step g until in whole boring 1 the injection pressure break of each pressure break position complete;

I, remove perforator 3, will hole 1 is connected with coal mine gas extraction system, carries out coal bed gas extraction.

In the present embodiment, the diameter of described boring 1 also can be other appropriate values that are greater than 120mm.

In the present embodiment, described boring also can be formed in seat earth 10.

Although combine above accompanying drawing, embodiments of the present invention are described, but those of ordinary skill in the art also can recognize making various variations or modification in the scope of claims, these modifications and variations are interpreted as within scope of the present invention and intention.

Claims (4)

1. a method for vectored injection pressure break exploiting coal bed methane under coal mine, is characterized in that, comprises the following steps:
A, in roof or base plate, form along the boring (1) in coal seam, between the center of this boring (1) and coal seam, there is setpoint distance (h);
B, in this boring (1), insert pressure break pipe group (2) and for the perforator of perforation (3) radially, and this perforator (3) is placed to the first perforation position that need to carry out pressure break;
C, described boring (1) is carried out to sealing of hole by pressure break seal request, form sealing of hole section (4) with the orifice end in boring (1), this sealing of hole section (4) forms static seal with pressure break pipe group (2), and forms movable sealing with the feed tube (31) of perforator (3);
D, pressure break pipe group (2) is connected with fracturing pump group (5) by pipe fitting; The feed tube of perforator (3) (31) is connected with perforation pump group (6);
E, by perforation pump group (6), the perforation medium pump that contains abrasive material is delivered to described perforator (3), and forming jetting stream by perforator (3), this jetting stream is penetrated and is worn the branched hole (8) that formation coal seam, rock stratum (7) is communicated with described boring (1);
F, inject fracturing fluid by fracturing pump group (5) and pressure break pipe group (2) to boring (1) internal pressure;
G, by described perforator (3) by this branched hole (8) to coal seam (7) spray setting-up time, and spray simultaneously and by fracturing pump group (5), the interior fracturing fluid of boring (1) is pressurizeed, and keep pressure and control fracturing flow quantity, so that the coal body of coal seam (7) forms the fracturing crack extending along direction at the bottom of the Perforation of coal seam;
H, close fracturing pump group (5), described perforator (3) is moved to next pressure break position, and form next branched hole (8) by perforation pump group (6) and perforator (3); Return to step g until in whole boring (1) the injection pressure break of each pressure break position complete;
I, dismounting perforator (3), will hole (1) is connected with coal mine gas extraction system, carries out coal bed gas extraction.
2. the method for vectored injection pressure break exploiting coal bed methane under coal mine according to claim 1, is characterized in that, described branched hole (8) also has the part that stretches into coal seam (7).
3. the method for vectored injection pressure break exploiting coal bed methane under coal mine according to claim 1 and 2, is characterized in that, described boring (1) is 0.5~1.0m with the distance (h) in coal seam.
4. the method for vectored injection pressure break exploiting coal bed methane under coal mine according to claim 1 and 2, is characterized in that, the diameter of described boring is more than or equal to 120mm.
CN201410163959.7A 2014-04-23 2014-04-23 Orientation jetting and fracturing exploitation method for coal bed gas under coal mine CN103883303A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104763398A (en) * 2015-02-11 2015-07-08 中国石油集团长城钻探工程有限公司 Mining method for deformed coal coalbed methane for V-shaped well bottom plate auxiliary layer
CN106285768A (en) * 2016-08-04 2017-01-04 重庆大学 CO2directional blasting crack initiation couples anti-reflection gas pumping method with fracturing
CN106437638A (en) * 2016-10-10 2017-02-22 太原理工大学 Method for improving coal bed gas recovery efficiency by electrochemistry
CN109339855A (en) * 2018-11-27 2019-02-15 中煤科工集团西安研究院有限公司 Continuous pipe perforation staged fracturing method in coal mine gas extraction jumping chisel hole sleeve
CN110130897A (en) * 2019-06-13 2019-08-16 中国神华能源股份有限公司 Roof weakening solution danger method
CN110259447A (en) * 2019-06-07 2019-09-20 太原理工大学 Underground coal mine oriented perforating pressure break cuts top release shield lane method
CN110953015A (en) * 2019-12-25 2020-04-03 太原理工大学 Soft low-permeability coal seam long-drill-hole directional segmented fracturing efficient gas extraction method

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CN102213077A (en) * 2011-05-25 2011-10-12 煤炭科学研究总院沈阳研究院 Coal seam reaming system using three-dimensional (3D) swirling water jet and reaming and fracturing method for permeability enhancement
CN102493833A (en) * 2011-11-25 2012-06-13 重庆市能源投资集团科技有限责任公司 Depressurized extraction method for cutting through roof or floor of coal seam by abrasive water jet
CN103147734A (en) * 2013-03-08 2013-06-12 中煤科工集团重庆研究院 Method for multi-section hydraulic fracture along coal layer of underground coal mine
CN103174453A (en) * 2013-03-28 2013-06-26 重庆大学 Layered hydraulic fracturing method of underground coal mine multiple coal seams
CN103696800A (en) * 2013-12-18 2014-04-02 中国矿业大学 Drilling, cutting, pressing and pumping method

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Publication number Priority date Publication date Assignee Title
NO833683L (en) * 1982-10-12 1984-04-13 Flow Ind Inc Procedure and apparatus for quarrying rock or bedrock, especially without the use of explosives
CN101575983A (en) * 2009-02-27 2009-11-11 河南省煤层气开发利用有限公司 Directional fracturing permeability improvement outburst elimination method in coal mine and device thereof.
CN101963066A (en) * 2010-03-03 2011-02-02 北京鑫源九鼎科技有限公司 Method for drawing out methane from bedding plane of coal seam by hydraulic fracturing
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104763398A (en) * 2015-02-11 2015-07-08 中国石油集团长城钻探工程有限公司 Mining method for deformed coal coalbed methane for V-shaped well bottom plate auxiliary layer
CN106285768A (en) * 2016-08-04 2017-01-04 重庆大学 CO2directional blasting crack initiation couples anti-reflection gas pumping method with fracturing
CN106437638A (en) * 2016-10-10 2017-02-22 太原理工大学 Method for improving coal bed gas recovery efficiency by electrochemistry
CN106437638B (en) * 2016-10-10 2019-11-12 太原理工大学 A kind of method that electrochemistry improves coal bed gas recovery ratio
CN109339855A (en) * 2018-11-27 2019-02-15 中煤科工集团西安研究院有限公司 Continuous pipe perforation staged fracturing method in coal mine gas extraction jumping chisel hole sleeve
CN110259447A (en) * 2019-06-07 2019-09-20 太原理工大学 Underground coal mine oriented perforating pressure break cuts top release shield lane method
CN110130897A (en) * 2019-06-13 2019-08-16 中国神华能源股份有限公司 Roof weakening solution danger method
CN110953015A (en) * 2019-12-25 2020-04-03 太原理工大学 Soft low-permeability coal seam long-drill-hole directional segmented fracturing efficient gas extraction method

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Application publication date: 20140625