CN105971662A - Method for gas extraction by coal seam roof weakening through L-shaped drilling staged fracturing - Google Patents

Method for gas extraction by coal seam roof weakening through L-shaped drilling staged fracturing Download PDF

Info

Publication number
CN105971662A
CN105971662A CN201610521767.8A CN201610521767A CN105971662A CN 105971662 A CN105971662 A CN 105971662A CN 201610521767 A CN201610521767 A CN 201610521767A CN 105971662 A CN105971662 A CN 105971662A
Authority
CN
China
Prior art keywords
roof
fracturing
type
pressure break
gas
Prior art date
Application number
CN201610521767.8A
Other languages
Chinese (zh)
Inventor
夏彬伟
王海洋
卢义玉
龚涛
葛兆龙
汤积仁
Original Assignee
重庆大学
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 重庆大学 filed Critical 重庆大学
Priority to CN201610521767.8A priority Critical patent/CN105971662A/en
Publication of CN105971662A publication Critical patent/CN105971662A/en

Links

Classifications

    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21FSAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
    • E21F7/00Methods or devices for drawing- off gases with or without subsequent use of the gas for any purpose

Abstract

The invention relates to a method for gas extraction by coal seam roof weakening through L-shaped drilling staged fracturing. The method comprises a step 1) of selecting drilling positions and parameters at a ground device corresponding to an exploited coal seam working face, and constructing an L-shaped drill hole; a step 2) of arranging a sleeve and a fracturing device in the L-shaped drill hole after the construction of the L-shaped drill hole, and utilizing a hydraulic jet staged fracturing method to fracture each preset fracturing site of a coal seam roof, so as to weaken the coal seam roof; a step 3) of dismantling the fracturing device and connecting the sleeve in the L-shaped drill hole to a gas extraction device, after fracturing operations are performed; a step 4) of starting coal mining operations of a coal mining working face, and extracting fracture zone gas through the gas extraction device while the coal mining working face moves forwards. According to the scheme, the problems that in the prior art, the gas extraction amount is limited, the extraction dynamics is insufficient, and the coal seam gas cannot be extracted and utilized in a large extent are solved.

Description

A kind of L-type drilling subsection pressure break weakens the mash gas extraction method of roof
Technical field
The present invention relates to gas pumping field, a kind of L-type drilling subsection pressure break weakens the mash gas extraction method of roof.
Background technology
China is coal production state maximum in the world and country of consumption, is also the most serious country of Gas Disaster, and Gas Disaster is seriously Govern the safety in production of China's coal-mine.In China, the coal of 94% is mined, however as colliery by well work method The underground mining degree of depth and the continuous of production capacity increase, and coal seam gas-bearing capacity and pressure constantly raise, and roof control is the most difficult, Mining face under mine danger is more and more higher.
Day by day severe for this and to deep formation exploitation will problems faced, China define a series of with pillar, Roof controlling method and gas lane extraction method, hole pumping and mining method and pipe laying that explosion, water filling softening and fracturing etc. are core are taken out Adopt the goaf gas pumping methods such as method.These roof controlling method and goaf gas pumping method serve in some mines Beneficial effect, but effect when each method is used alone after all is limited, and often due to the complex situations of down-hole cause these methods Its effect can not be fully played.It is limited primarily to extraction by losing coal and a small amount of coal seam again due to common goaf gas pumping method Loss out accumulates to the gas in goaf, and the liter of gas float-spreads and accumulation effect makes the gas density in goaf be distributed In lower low high situation, so the drainage tube of common gas pumping method is often because be arranged to close to base plate, cause watt This extraction concentration is low and is easily blocked by the rock of erecting dense individual props or destroys;When two drainage tubes are spaced farther out, leave pumping blind zone. It is inadequate that these reasons all will result in gas pumping amount finite sum extraction dynamics, does not reaches and makes coal-bed gas dramatically by extraction profit Purpose.
Summary of the invention
It is an object of the invention to provide a kind of L-type drilling subsection pressure break and weaken the mash gas extraction method of roof, it can solve Certainly in prior art, gas pumping amount finite sum extraction dynamics is inadequate, does not reaches and makes coal-bed gas dramatically by methane drainage and utilization project Problem.
To achieve the above object of the invention, technical scheme is as follows:
A kind of L-type drilling subsection pressure break weakens the mash gas extraction method of roof, it is characterised in that comprise the steps of:
1) bore position and parameter, construction L-type boring are chosen at the ground location that institute's mining coal seam work surface is corresponding.
2) in L-type is holed, arrange sleeve pipe and fracturing unit after described L-type drilling construction, utilize water-jet staged fracturing The each default pressure break place of method pressure break roof, to weaken roof.
3) after fracturing work completes, removal fracturing unit and by L-type hole in telescopic joint to gas pumping device.
4) coal mining activity of coal-face is started, and by gas pumping device extraction while coal-face elapses forward Fissure zone gas.
Preferably, described step 1) in, the boring of described L-type includes the straight hole section towards roof and parallel with roof Horizontal segment, described straight hole section and horizontal segment connect transition by inclination section, and the horizontal segment of L-type boring is arranged in preparation face Potential fissure zone above coal seamIn the range of;Wherein, HLminFor under fissure zone height Limit value, HLmaxFor fissure zone height upper limit value.
Preferably, described step 1) in, adjacent two L-type borings projection pitch on roof is L2, it is individual that L-type is holed Number N=L1/L2, wherein, L1For the length of working face of coal seam, L2The reference value obtained for numerical simulation or test.
Preferably, described step 2) in, along the opposite direction of drilling construction along drag fracturing equipment in the horizontal segment of L-type boring Fracturing string, the successively each default pressure break place of pressure break roof, spacing L of hydraulic jetting fracturing3Value is the distance of face roof under control.
Preferably, the leachy gas pumping pipe of tool is set in described sleeve pipe.
For overcoming the deficiencies in the prior art, it is mined out that the present invention utilizes same boring to carry out extraction after pressure break weakens roof District's fissure zone gas, it is by holing in ground construction L-type, utilizes L-type boring to drill in the roof of preparation face, The method using waterpower staged fracturing carries out staged fracturing to roof in drilling horizontal section is arranged in fissure zone, and pressure break weakens After top board, promote top board to elapse forward with work surface and be progressively caving, recycle former L-type and hole by post-fracturing fracture connectivity And position advantage, telescopic joint elapse post-fracturing forward to gas pumping device with coal-face, extraction fissure zone watt This.
The method can not only carry out staged fracturing to roof, reaches to weaken the purpose of roof;And can also realize respectively Plant reason and cause the extraction of the gas accumulated in above goaf fissure zone.The present invention is with L-type boring as carrier, by segmentation Fracturing technique combines with gas pumping technology, with the method probing into the multiplex pressure break mash gas extraction in an a kind of hole.Utilize same brill After hole carries out pressure break, mash gas extraction greatly reduces construction cost and time cost, drastically increases gas pumping efficiency.
The method have the advantages that
1) in potential fissure zone, carry out water-jet staged fracturing can promote the growth in crack in fissure zone in the future, promote that top board collapses Fall, release, weaken top board.
2), after implementing pressure break, it is provided that more gas migration passage, the gas accumulating in fissure zone is made to be easier to by extraction, And utilize negative pressure extraction can promote a large amount of desorbings of coal-bed gas, and make gas extraction concentration higher, extraction amount is bigger.
3) utilize same boring to carry out pressure break and construction cost and time cost had both been saved in extraction, also give full play to pressure break reduction Top board and in fissure zone the double dominant of mash gas extraction.
4) it is China's coal-mine roof control and gas control provides and a kind of is different from traditional New methods in working.
Accompanying drawing explanation
Fig. 1 is the structural representation of the L-type boring of the present invention;
Fig. 2 is that the vertical section of the L-type boring of the present invention arranges schematic diagram;
Fig. 3 is that the horizontal profile of the L-type boring of the present invention arranges schematic diagram;
Fig. 4 is the principle schematic of the water-jet that the present invention uses;
Fig. 5 is the drag fracturing design sketch of the present invention;
Fig. 6 is the gas pumping design sketch of the present invention.
Description of reference numerals: R-radius of turn;A-straight hole section;B-inclination section;C-horizontal segment;D-caving zone;E-fissure zone; F-warp damage;M-mining thickness (for accumulative mining height during separate zone production);L1-face length;L2-the spacing of wells;L3- Hydraulic jetting fracturing spacing (distance of face roof under control);1-L type is holed;2-fracturing fracture;3-fracturing fluid;4-annular fluid;5-nozzle; 6-annular space low-pressure area;Nip in 7-annular space;8-annular space higher-pressure region;9-gas.
Detailed description of the invention
The invention will be further described with embodiment below in conjunction with the accompanying drawings.
The step of the present invention is as follows:
1) bore position and parameter, construction L-type boring 1 are chosen at the ground location that institute's mining coal seam work surface is corresponding.
According to surface-underground contrast plan, find the ground location that preparation face institute mining coal seam is corresponding, select one group of ground even, sky Spacious, traffic and convenient construction, the construction site not threatened by natural disasters such as flood, fire and landslides carries out L-type drilling construction. Select TD2000/600 type hydraulic pressure top drive drilling, use advanced Technology of Directional Drilling to carry out directly in selected surface drilling position Adjust gyroscope angle after the section construction of hole and carry out inclination section construction (as shown in Figure 1).
Notable, to 2/3 times in the middle part of potential fissure zone above coal seam, preparation face for making pressure break weaken top board after gas extracting result In fissure zone altitude range, i.e. existIn the range of, it is adjusted to be parallel to coal by drilling rod The position of layer, and run through the roof treating pressure break.
Wherein, HLminAccording to empirical equation gained fissure zone height lower limit, m;HLmaxSplit according to empirical equation gained Gap band height upper limit value, m;Fissure zone height HLDetermined by following formula:
Competent bed:
Medium ground:
In formula, M is mining thickness, for accumulative mining height, m during separate zone production.
Adjacent two L-type borings projection pitch on roof is L2, number N=L of L-type boring1/L2, after calculating four House five enters value;Wherein, L1For the length of working face of coal seam, L2The reference value obtained for numerical simulation or test.L-type is holed Arrange as shown in Figure 2 and Figure 3.
2) in L-type boring 1, arrange sleeve pipe and fracturing unit after described L-type drilling construction, utilize water-jet segmentation pressure The each default pressure break place of the method pressure break roof split, to weaken roof.
Described step 2) in, for making top board can be caving in time after pressure break, hydraulic jetting fracturing spacing L3Value is the distance of face roof under control, logical Cross the fracturing string of drag fracturing equipment nozzle is dragged to each pressure break place (such as Fig. 5) can pressure break all required pressure breaks successively Place.
3) after fracturing work completes, removal fracturing unit and by L-type boring 1 in telescopic joint to gas pumping device.In standard Before standby work surface seam mining, first desire pressure break place each to top board carries out sufficient hydraulic jetting fracturing, pressure break terminate after successively Fracturing unit is taken apart from boring, but retains the sleeve pipe in boring, and by telescopic joint to gas pumping device, under One step extraction fissure zone gas is prepared.
4) coal mining activity of coal-face is started, and by gas pumping device extraction while coal-face elapses forward Fissure zone gas 9.
Step (3) proceeds by coal mining activity after completing, and elapses forward with coal-face, and top board is progressively caving, and gas 9 is gradually Run up to above fissure zone, extraction fissure zone gas 9 while mining.If occurring during extraction, sleeve pipe is blocked, can Enter under in sleeve pipe and carry leachy gas pumping pipe.
If occurring during extraction, sleeve pipe is blocked, can arrange the leachy gas pumping pipe of tool in described sleeve pipe.
In step (1), L-type boring 1 completes to load in backward boring sleeve pipe, utilizes water-jet specific purpose tool to produce high speed and high pressure Fluid is shot through sleeve pipe and balkstone forms eyelet, and fracturing fluid is supercharging in injection channel under high pressure effect, and annular fluid makes Annular pressure raise, frac fluid pressure and annular pressure exceed roof strata fracture pressure after being overlapped mutually time roof strata then by Press off;This water-jet principle (such as Fig. 4) is by Bernoulli equation:Getting, fluid is when by spraycan The pressure energy of fluid is converted into kinetic energy, carries out perforation under high velocity fluid strikes effect, and after perforation forms crack, fluid sprays Entering crack and maintain extension and the extension in crack together with annular fluid, whole injection fracturing process uses principles of hydrodynamics to realize Packing, it is not necessary to mechanical packing.
Roof is cranny development after injection pressure break, and the top board above work surface elapses forward with work surface and is gradually caving, work In face of work, the top board of side gradually ruptures under pressure break crack and mining influence, sinks, and its gravity is applied on coal body press the most further Crisp coal body, makes the gas in coal body enter into extraction scope along pressure break crack;The gas in goaf spills into fissure zone top also Within the scope of extraction, and extraction after pressure break, gas extraction concentration is higher, and it is wider that energy extraction is arrived, as long as L-type is bored Coal seam under hole 1 horizontal segment covers also has not been adopted, and has necessity of gas pumping, all can carry out lasting gas pumping operation.Pressure Split after gas extraction schematic diagram as shown in Figure 6.
The present invention answers China's each big colliery management top board and the demand of mash gas extraction, caters to the inexorable trend of following coal deep mining, In conjunction with staged fracturing technology and gas pumping technology, it is place and the gas ease of methane accumulation at Overlying Strata In A Face fissure zone Under the theoretical direction of the passage dissipated, in potential fissure zone, arrange L-type boring 1, and lead to extraction as pressure break with L-type boring 1 Road carries out pressing crack construction and mash gas extraction, and final realization weakens top board and extraction fissure zone gas, for China's pressure break roof, Mash gas extraction provides a kind of New methods in working.

Claims (5)

1. the mash gas extraction method of a L-type drilling subsection pressure break reduction roof, it is characterised in that comprise the steps of:
1) bore position and parameter, construction L-type boring are chosen at the ground location that institute's mining coal seam work surface is corresponding;
2) in L-type is holed, arrange sleeve pipe and fracturing unit after described L-type drilling construction, utilize water-jet staged fracturing The each default pressure break place of method pressure break roof, to weaken roof;
3) after fracturing work completes, removal fracturing unit and by L-type hole in telescopic joint to gas pumping device;
4) coal mining activity of coal-face is started, and by gas pumping device extraction while coal-face elapses forward Fissure zone gas.
A kind of L-type drilling subsection pressure break the most according to claim 1 weakens the mash gas extraction method of roof, its feature It is, described step 1) in, the boring of described L-type includes the straight hole section towards roof and the level parallel with roof Section, described straight hole section connects transition with horizontal segment by inclination section, and the horizontal segment of L-type boring is arranged on coal seam, preparation face The potential fissure zone of sideIn the range of;
Wherein, HLminFor fissure zone height lower limit, HLmaxFor fissure zone height upper limit value.
A kind of L-type drilling subsection pressure break the most according to claim 1 weakens the mash gas extraction method of roof, its feature It is, described step 1) in, adjacent two L-type borings projection pitch on roof is L2, the number of L-type boring N=L1/L2, wherein, L1For the length of working face of coal seam, L2The reference value obtained for numerical simulation or test.
A kind of L-type drilling subsection pressure break the most according to any one of claim 1 to 3 weakens the mash gas extraction of roof Method, it is characterised in that described step 2) in, along the opposite direction of drilling construction along drag fracturing in the horizontal segment of L-type boring The fracturing string of equipment, the successively each default pressure break place of pressure break roof, spacing L of hydraulic jetting fracturing3Value is control top Away from.
A kind of L-type drilling subsection pressure break the most according to claim 4 weakens the mash gas extraction method of roof, its feature It is, the leachy gas pumping pipe of tool is set in described sleeve pipe.
CN201610521767.8A 2016-07-05 2016-07-05 Method for gas extraction by coal seam roof weakening through L-shaped drilling staged fracturing CN105971662A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201610521767.8A CN105971662A (en) 2016-07-05 2016-07-05 Method for gas extraction by coal seam roof weakening through L-shaped drilling staged fracturing

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201610521767.8A CN105971662A (en) 2016-07-05 2016-07-05 Method for gas extraction by coal seam roof weakening through L-shaped drilling staged fracturing

Publications (1)

Publication Number Publication Date
CN105971662A true CN105971662A (en) 2016-09-28

Family

ID=56954915

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201610521767.8A CN105971662A (en) 2016-07-05 2016-07-05 Method for gas extraction by coal seam roof weakening through L-shaped drilling staged fracturing

Country Status (1)

Country Link
CN (1) CN105971662A (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106761406A (en) * 2016-12-02 2017-05-31 淮北矿业(集团)有限责任公司 A kind of ground L-type mash gas pumping drilling
CN107387082A (en) * 2017-07-31 2017-11-24 山西晋城无烟煤矿业集团有限责任公司 A kind of method for weakening coal seam tight roof
CN109519211A (en) * 2019-01-15 2019-03-26 中煤科工集团重庆研究院有限公司 A method of coal bed gas surface well extraction minery gas is taken out using pre-
CN110067592A (en) * 2019-03-25 2019-07-30 大同煤矿集团有限责任公司 Top plate gas cooperative control method based on tight roof ground fracturing
CN110080769A (en) * 2019-05-09 2019-08-02 大同煤矿集团有限责任公司 A kind of coal mine faces sky stope drift active workings tight roof ground and precisely cuts top pressure relief method
CN110173240A (en) * 2019-06-19 2019-08-27 陕西浩兴坤达新能源科技有限公司 A kind of coal mine gas drainage method
CN110306961A (en) * 2019-06-19 2019-10-08 陕西浩兴坤达新能源科技有限公司 It is a kind of along roof Floor water horizontal well drilling well staged fracturing method
WO2019228042A1 (en) * 2018-07-03 2019-12-05 安徽理工大学 Hydraulic perforation unmanned gas extraction method

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
CN102080526A (en) * 2011-01-17 2011-06-01 河南理工大学 Method for extracting gas from bedding level fractured well of ground coal seam roof
CN102086774A (en) * 2011-01-17 2011-06-08 中联煤层气国家工程研究中心有限责任公司 Drainage method of gas in coal bed
CN102852546A (en) * 2011-06-30 2013-01-02 河南煤业化工集团研究院有限责任公司 Method for pre-pumping coal roadway stripe gas of single soft protruded coal seam of unexploited area
RU2571464C1 (en) * 2014-12-12 2015-12-20 Федеральное государственное автономное образовательное учреждение высшего профессионального образования "Национальный исследовательский технологический университет "МИСиС" Preliminary degassing of coal series and worked-out area

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
CN102080526A (en) * 2011-01-17 2011-06-01 河南理工大学 Method for extracting gas from bedding level fractured well of ground coal seam roof
CN102086774A (en) * 2011-01-17 2011-06-08 中联煤层气国家工程研究中心有限责任公司 Drainage method of gas in coal bed
CN102852546A (en) * 2011-06-30 2013-01-02 河南煤业化工集团研究院有限责任公司 Method for pre-pumping coal roadway stripe gas of single soft protruded coal seam of unexploited area
RU2571464C1 (en) * 2014-12-12 2015-12-20 Федеральное государственное автономное образовательное учреждение высшего профессионального образования "Национальный исследовательский технологический университет "МИСиС" Preliminary degassing of coal series and worked-out area

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106761406A (en) * 2016-12-02 2017-05-31 淮北矿业(集团)有限责任公司 A kind of ground L-type mash gas pumping drilling
CN107387082A (en) * 2017-07-31 2017-11-24 山西晋城无烟煤矿业集团有限责任公司 A kind of method for weakening coal seam tight roof
WO2019228042A1 (en) * 2018-07-03 2019-12-05 安徽理工大学 Hydraulic perforation unmanned gas extraction method
CN109519211A (en) * 2019-01-15 2019-03-26 中煤科工集团重庆研究院有限公司 A method of coal bed gas surface well extraction minery gas is taken out using pre-
CN110067592A (en) * 2019-03-25 2019-07-30 大同煤矿集团有限责任公司 Top plate gas cooperative control method based on tight roof ground fracturing
CN110067592B (en) * 2019-03-25 2021-04-09 晋能控股煤业集团有限公司 Roof gas cooperative control method based on hard roof ground fracturing
CN110080769A (en) * 2019-05-09 2019-08-02 大同煤矿集团有限责任公司 A kind of coal mine faces sky stope drift active workings tight roof ground and precisely cuts top pressure relief method
CN110173240A (en) * 2019-06-19 2019-08-27 陕西浩兴坤达新能源科技有限公司 A kind of coal mine gas drainage method
CN110306961A (en) * 2019-06-19 2019-10-08 陕西浩兴坤达新能源科技有限公司 It is a kind of along roof Floor water horizontal well drilling well staged fracturing method

Similar Documents

Publication Publication Date Title
CN103670496B (en) Single low permeability outburst coal seam gob side entry retaining with take out section coal-bed gas method in advance
CN102747997B (en) Fire-flooding exploitation method used in later period of steam assisted gravity drainage (SAGD) of heavy oil reservoir
CN103527200B (en) Bottom-column-free sectional Rhombic room afterwards filling mining method
CN103953343B (en) A kind of method coal seam tight roof being controlled to caving
CN103527198B (en) Cut a tight roof/top coal hydraulic fracture control method
CN101446178B (en) Wind pressure air drilling equipment in downhole soft outbursting coal bed and process matched therewith
CN101403314B (en) Coal mine down-hole drilling hydraulic fracturing anti-reflection mash gas extraction technique
CN104131831B (en) A kind of coal bed gas well three-dimensional associating pumping method up and down
CN104847355B (en) Continuous mining method of medium-thick heavy pitch ore body empty field
CN102116140B (en) Construction method for enhancing extraction effect of ground coal bed gas
CN106640027B (en) The construction method of fracture-pore reservoir underground river type karst Reservoir Body space structure well pattern
CN100356036C (en) Method for pumping out gas from mining coal layer roof
CN100441831C (en) Ladder type mining method using united pillars to support roof and partition stope
CN101275469B (en) Yolk coal rock formation downward hole pumping and mining pressure relief mash gas construction method
CN104389631B (en) A kind of low air permeability coal seam slot and pressure break contract network anti-reflection method
CN101575983B (en) Directional fracturing permeability improvement outburst elimination method in coal mine and device thereof.
CN104100292A (en) Regional forced gas extraction method for single low-permeability outburst thick coal seam
Sang et al. Stress relief coalbed methane drainage by surface vertical wells in China
CN100462523C (en) Gob-side entry retaining Y-type ventilation goaf top plate pressure relief gas pumping mining method
CN102080526B (en) Method for extracting gas from bedding level fractured well of ground coal seam roof
CN102168575B (en) Loose blasting gas extraction technology for horizontal branch well of coal seam floor
CN101915072B (en) Method for extracting coal bed gas in stable mining region by ground well drilling
CN103089266A (en) Drift-pillar-free sublevel barnyard caving mining method of open pit transferred underground transitional period
CN104790951B (en) Weaken the method and device away from the high-order tight roofs of 100 ~ 350m of coal seam
CN102518436B (en) Method for controlling tectonic rock burst in coal mine tunneling

Legal Events

Date Code Title Description
PB01 Publication
C06 Publication
SE01 Entry into force of request for substantive examination
C10 Entry into substantive examination
RJ01 Rejection of invention patent application after publication

Application publication date: 20160928

RJ01 Rejection of invention patent application after publication