CN106285679B - A kind of presplitting and the method for softening igneous rock tight roof - Google Patents

A kind of presplitting and the method for softening igneous rock tight roof Download PDF

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Publication number
CN106285679B
CN106285679B CN201610659540.XA CN201610659540A CN106285679B CN 106285679 B CN106285679 B CN 106285679B CN 201610659540 A CN201610659540 A CN 201610659540A CN 106285679 B CN106285679 B CN 106285679B
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igneous rock
rock
softening
pressure
tight roof
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CN201610659540.XA
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Chinese (zh)
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CN106285679A (en
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冯国瑞
郭军
申辰
王贵文
戚庭野
闫勇敢
张玉江
李振
杜献杰
白锦文
康立勋
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太原理工大学
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    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21CMINING OR QUARRYING
    • E21C41/00Methods of underground or surface mining; Layouts therefor
    • E21C41/16Methods of underground mining; Layouts therefor
    • E21C41/18Methods of underground mining; Layouts therefor for brown or hard coal
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21CMINING OR QUARRYING
    • E21C37/00Other methods or devices for dislodging with or without loading
    • E21C37/06Other methods or devices for dislodging with or without loading by making use of hydraulic or pneumatic pressure in a borehole
    • E21C37/12Other methods or devices for dislodging with or without loading by making use of hydraulic or pneumatic pressure in a borehole by injecting into the borehole a liquid, either initially at high pressure or subsequently subjected to high pressure, e.g. by pulses, by explosive cartridges acting on the liquid

Abstract

The invention discloses a kind of presplitting and the method for softening igneous rock tight roof, while superjacent is exploited, grasping coal seam spacing up and down, under the premise of interlayer nature of ground and the intrusion situation of igneous rock competent bed, while superjacent is exploited, by drilling in top floor undulation reasonable Arrangement, high pressure acid solution is injected, the pressure of acid solution is injected by fracture acidizing unit allocation, on the one hand hard igneous rock rock stratum is made to generate crack using pressure;On the other hand further hard igneous rock rock stratum is softened using the chemical reaction of acid solution effect, finally realizes the effect of safe and efficient rupture and the lower hard igneous rock top plate in coal seam of softening.This method drills acid filling while superjacent is exploited, and destroys the tight roof structure of underlying seam, reduces its intensity;Weaken even avoid underlying seam exploitation when, igneous rock tight roof working face is normally exploited and to personnel equipment may caused by harm.

Description

A kind of presplitting and the method for softening igneous rock tight roof
Technical field
The present invention relates to a kind of presplitting and softening igneous rock tight roof, ensure that working face is safe and efficient and are invaded by igneous rock Enter the method in area, and in particular to a kind of method for drilling in advance, noting the rupture of high pressure acid solution and softening igneous rock tight roof belongs to In coal mining technology field.
Background technology
With the increasingly reduction of Jurassic coal carbon resource, the exploitation of Carbon Permian seam is gradually unfolded, and becomes and work as Under main coal seam.However, the sill that wherein Igneous rock invasion after is formed and its right changeable in the coal measure strata complex geologic conditions The destruction of coal rock layer property becomes the very always factor for restricting coal seam safety and high efficiency.The intrusion of igneous rock, on the one hand makes coal Layer silication is serious, loses a large amount of fat coals, on the other hand forms tight roof, change coal seam rock property and structure.
Hard igneous rock top plate due to intensity it is high, it is fine and close with integrality is good, joint and cranny development are inadequate, exists The features such as the dirt band of high stability cause the top plate during working face extraction to be not easy to be caving, especially in first weighting Before, top plate easily forms large area and hangs top, serious possibly even to form ore deposit shake.This not only causes working face to leak out seriously, A series of problems, such as easily causing face gas accumulation and spontaneous combustion in goaf, and hang when top is caving and generate in large area Strong impact air-flow, easily lead to working face occur such as Gas Outburst impact disaster, the person of serious threat coal miner The steady running of safety and production equipment brings severe challenge to Safety of Coal Mine Production.
However, igneous rock top plate into harm often have certain sudden, caused to in-situ processing greatly tired Difficulty seriously restricts safe and efficient production.Such as Datong Mine Area exploitation Carbon Permian seam group, the coal measure strata minable coal seam For the coal seam of mountain 4, No. 2 coal seams, No. 3 coal seams, 3-5 super high seams and No. 8 coal seams.Each coal seam is in various degree by igneous rock Intrusion, and the top of 3-5 super high seams is formed large-scale igneous rock tight roof by large area stratiform Igneous rock invasion. Super high seam adopts that range is big in itself, along with the influence of tight roof, often generates uncontrollable roof accident.
The method of existing processing tight roof mainly has hydrofracturing softening top plate (104790951 A of Chinese patent CN Method and device of the reduction away from coal seam 100~350m high position tight roofs is disclosed, 103527198 B of Chinese patent CN are disclosed Cut tight roof top coal hydraulic fracture control method) and explosion presplitting softening (103206903 B of Chinese patent CN are disclosed A kind of tight roof orientation pressure-bearing Blasting Control method, it is deep that Chinese patent CN 103278055 B disclose a kind of tight roof Top pressure relief method is cut in hole presplit blasting).The mode complex management of explosion presplitting, is related to explosive, detonator is regulated the traffic, and blows out Want strict implement " a big gun tri-inspection system " and " three people's linkage blasting systems ";The pernicious gases such as a large amount of CO that explosion instantaneously generates are to mine Ventilation safety management causes tremendous influence, forms security risk;And explosion financial cost is higher.By the prior art and equipment Limitation, equipment requirement condition is high and there are some potential safety problems under the conditions of high pressure water injection, therefore the hydraulic pressure under the conditions of tight roof Fracturing reduction technical controlling effect is not notable.In addition, above-mentioned two classes method is implemented in the exploitation in this coal seam engineering, it is right Production efficiency in coal seam has significant effect, and the uncontrollable situation of top plate easily occurs in the process for handling top plate, for The safety of working face has great threat.It, just will be hard before the coal seam with tight roof is exploited if can be by certain method Top plate gives presplitting and softening, in advance excludes potential threat existing for tight roof, can be achieved with the safety of working face in this way Efficiently production.And in fact, away from there are two layers of Main workable coal seams in the range of 30m above Permo-Carboniferous system 3-5 super high seams, The respectively coal seam of mountain 4 and No. 2 coal seams, and the mining conditions of this two layers of coal are relatively easy, and hard apart from lower part igneous rock Top plate is closer to the distance, thus provides good implementation condition to shift to an earlier date presplitting and softening lower part igneous rock tight roof.
Invention content
The present invention is intended to provide a kind of method of presplitting and softening igneous rock tight roof, is working in practice for engineering Face directly implements top plate presplitting and there are problems that influencing the safe and efficient production of working face, while top contiguous seams are exploited It drills in its floor strata (i.e. the roof strata of underlying seam), and injects high pressure acid solution, realize under rupturing and softening in advance The purpose of portion coal seam tight roof is avoiding tight roof accident, under the premise of fully ensuring that working face personnel and equipment safety, The production efficiency of working face is improved to greatest extent.
The present invention provides a kind of presplitting and the method for softening igneous rock tight roof, this method is between coal seam up and down is grasped Away from before the intrusion situation (specifically including Igneous rock invasion layer position and thickness) of interlayer nature of ground and igneous rock competent bed It puts, while superjacent is exploited, by drilling in top floor undulation, injects high pressure acid solution, pass through pressure break acid Change the pressure of unit allocation injection acid solution, on the one hand hard igneous rock rock stratum is made to generate crack using pressure;On the other hand profit Further hard igneous rock rock stratum is softened with the chemical reaction effect of acid solution, it is final to realize rupture and the lower coal of softening The effect of the hard igneous rock top plate of layer.
Specifically, the above method includes the following steps:
Step 1:By surface drilling coring and the method for physical prospecting (electrical method and magnetic method), the property of exploiting field coal rock layer is determined With composition situation.Determine that the physico-mechanical properties of upper and lower coal seam spacing and each rock stratum of interlayer and petrology are special by laboratory test Property;
Step 2:The depth of drilling that the spacing of coal seam up and down determined according to previous step determines.According to hard igneous rock Mechanical property determine fracturing pump provide pressure.The acid solution according to used in determining the mineral composition of igneous rock and chemical composition Concentration;
Step 3:By analyzing ultimate strength that stent bears compared with the actual strength that stent is born, igneous rock is determined The permission broken mechanics of tight roof, and the spacing of wells is determined according to this;
Step 4:After determining the spacing of wells, when implementing driller's operation, to ensure good fracturing effect, avoid simultaneously Occur cutting top phenomenon during lower seam mining, drilling need to be in 15 °~45° angle with vertical direction;
Step 5:After completing drilling according to above-mentioned steps, acid solution and right is injected into drilling using fracture acidizing unit Drilling carries out pressure break and softening;
Step 6:After complete pressure break and softening operation, acid solution remaining in drilling is recycled;
Step 7:Complete a pressure break after, with the superjacent advance of the face to pre-set pressure break apart from when It repeats the above steps, continues to carry out pressure break to igneous rock tight roof.
In said program, drilling depth is the interlamellar spacing of upper and lower two layers of coal, and bore diameter is 75~100mm.
The spacing of wells determines to be determined by equation below in the above method:
In formula:p0For stent ultimate strength allowed to bear;LkFor the stent distance of face roof under control;M is makees top plate thickness;γ is top plate Rock unit weight.
Calculating gained igneous rock tight roof according to the formula allows broken mechanics to be the spacing of wells;
In said program, determine that the property of coal rock layer and composition situation is taken to specifically include intrusion layer position and the thickness of igneous rock Degree;The physico-mechanical properties of interlayer rock stratum include the fundamental strength parameter of igneous rock, mainly have compression strength, tensile strength and resist Cut intensity;Mainly the mineral composition comprising igneous rock and its content, emphasis consider the content of carbonate mineral to petrology characteristic.
The pressure of fracturing pump offer is mainly determined according to the intensity of igneous rock and its residing layer position in said program, the pressure There can be the following formula to determine:
Wherein:pbFor the fracture pressure for the palisades that drill, MPa;
poFor the pore pressure of rock, MPa;
efFor the intensity of tensile stress of rock, i.e. rupture stress, MPa;
ehFor stratum minimum horizontal principal stress, MPa;
eHFor stratum maximum horizontal principal stress, MPa;
Z is poroelasticity constant;
OcFor the contact porosity of rock, %.
These parameters can be measured by laboratory test.
The determining of the concentration of acid solution need to determine according to the content of carbonate mineral contained in igneous rock in said program, And the content of carbonate mineral can analyze acquisition by X-ray diffraction (XRD) in igneous rock.The principle of hydrochlorate reaction is as follows:
2H++CO3 -2=H2O+CO2
Fracture acidizing unit mainly preserves device by fracturing pump, digital control system, pipe-line system and fracturing fluid in said program Composition.The HCl solution that mass concentration is 15%~28% is pumped into drilling by fracturing pump, pumping pressure is set, to fire Diagenesis tight roof carries out pressure break, while reacts softening with what carbonate mineral contained in igneous rock carried out using acid solution Igneous rock.The acid solution in drilling is recycled after completing pressure break.
Beneficial effects of the present invention:
(1) with it is existing to the technology of top plate drilling presplitting compared with, this method is to drill to bottom plate, and difficulty of construction significantly drops Low, operability is stronger;
(2) compared with the method for the presplitting top plate of deep hole blasting, this method can avoid the hidden danger that explosion presplitting is brought, such as Encounter operating environment gas bearing capacity it is high when, very big security risk that explosion has;
(3) compared with the method for the hydraulic fracturing used in existing coal mine, this method carries out pressure break with acid solution, faces For the higher igneous rock tight roof of carbonate mineral component content, softening and presplitting effect are more obvious;
(4) physics is rented rupture and is combined well with chemical action softening by this method, can guarantee pole under the premise of safety Big degree puies forward the efficiency of processing tight roof problem.
Description of the drawings
Fig. 1 is presplitting and softening igneous rock tight roof schematic diagram.
Fig. 2 is Section A-A drilling arrangement schematic diagram in Fig. 1.
Fig. 3 is section B-B drilling arrangement schematic diagram in Fig. 1.
Fig. 4 is pressure break, bating effect figure.
Fig. 5 is Tashan Mountain mine stratigraphic column.
1 is superjacent in figure, and 2 be interlayer rock stratum, and 3 be hard igneous rock rock stratum, and 4 be underlying seam, and 5 be pressure break machine Group, 6 be hydraulic support, and 7 be drilling, and 8 be the spacing of wells, and 9 be bore angle, and 10 be acid solution, and 11 be fracturing fracture.
Specific embodiment
It is further illustrated the present invention below by embodiment, but is not limited to following embodiment.
Embodiment:
By taking Datong District's ore deposit Carbon Permian seam as an example, minable coal seam distribution situation is as shown in table 1, Tashan Mountain mine stratigraphic column Shape figure is as shown in Figure 5.
1 Datong Mine Area Permo-Carboniferous system minable coal seam distribution situation of table
With reference to table 1 and Fig. 5 it is found that Tashan Mountain mine Permo-Carboniferous system minable coal seam is mountain4Number coal seam and 3-5 coal seams, No. 2 Coal seam is invaded seriously by igneous rock (lamprophyre), can not largely be adopted, and is invaded at the top of 3-5 super high seams by stratiform lamprophyre, Thickness is most thick reaches 6m, mountain for intrusion4Number coal seam can be adopted by lamprophyre intrusion part.Wherein, mountain4Number coal seam and 3-5 super high seams Average headway is 26m.
There are problems that rhythm tight roof for lower part super high seam, on top mountain4The long-armed work in number coal seam Make face and top mountain is exploited using longwork using the method for the presplitting softening that drills4While number coal seam, before hydraulic support It drills immediately below direction, concrete operations are as follows:
(1) it while superjacent 1 is exploited, arranges drilling 7 to the tight roof of underlying seam 4 and injects acid solution 10;It is drilled into the hard igneous rock rock stratum 3 above the 3-5# coal seams of lower part, is drilled along superjacent working face cloth with 80mm drill bits It puts, bore angle 9 is determined as 15 °.It is utilized with reference to the supporting intensity of interlayer nature of ground and lower part working surface hydraulic support 6 following Formula determines that the spacing of wells 8 is:
In formula:Stent ultimate strength p allowed to bear0For 1.5MPa;Stent distance of face roof under control LkFor 5m;Igneous rock tight roof Thickness m is 6m;Hard igneous rock balkstone unit weight γ is 2700N/m3
(2) pressure for being pumped into hydrochloric acid solution is controlled by Frac unit 5, until higher than stratum rock rupture pressure or being more than Intrinsic fracture clossing pressure;The mass fraction of hydrochloric acid is 20%.
It is determined as according to the intensity of hard igneous rock top plate and its crustal stress of residing layer position, the pressure for being pumped into acid solution 15.5MPa。
Rock rupture pressure is determined by the following formula:
Wherein:pbFor the fracture pressure for the palisades that drill, MPa;
poFor the pore pressure of rock, MPa;
efFor the intensity of tensile stress of rock, i.e. rupture stress, MPa;
ehFor stratum minimum horizontal principal stress, MPa;
eHFor stratum maximum horizontal principal stress, MPa;
Z is poroelasticity constant;
OcFor the contact porosity of rock, %.
According to tunnel passing through solution cavity in Taishan mine coal petrography mechanical characteristic, the pore pressure p of rock is determinedoFor 12MPa, the intensity of tensile stress of rock efFor 8MPa, stratum maximum horizontal principal stress eHWith stratum minimum horizontal principal stress ehRespectively 12MPa and 9MPa, rock touch Point porosity Oc0.5, poroelasticity constant Z is taken to take 0.035, substituting into rock rupture pressure formula can must drill the rupture pressures of palisades Power is 15.5MPa.
(3) pass through pressure break and emollescence so that after hard igneous rock top plate forms crack 11, stand 8 hours and recycle Acid solution in drilling;
(4) it after working face pushes ahead the distance (43m) of a spacing of wells, repeats the above steps.

Claims (7)

1. a kind of presplitting and the method for softening igneous rock tight roof, it is characterised in that:Include the following steps:
Step 1:By surface drilling coring and the method for physical prospecting, determine the property of exploiting field coal rock layer and composition situation, pass through reality It tests room experiment and determines coal seam spacing and the physico-mechanical properties of each rock stratum of interlayer and petrology characteristic up and down;
Step 2:The depth of drilling that the spacing of coal seam up and down determined according to previous step determines, according to the power of hard igneous rock It learns property and determines the pressure that fracturing pump provides, acid solution is dense according to used in determining the mineral composition of igneous rock and chemical composition Degree;
Step 3:By analyzing ultimate strength that stent bears compared with the actual strength that stent is born, determine that igneous rock is hard The permission broken mechanics of top plate, and the spacing of wells is determined according to this;
Step 4:After determining the spacing of wells, when implementing driller's operation, to ensure good fracturing effect, while lower coal is avoided Occur cutting top phenomenon in layer recovery process, drilling need to be in 15 °~45° angle with vertical direction;
Step 5:After completing drilling according to above-mentioned steps, acid solution inject into drilling using fracture acidizing unit and to drilling Carry out pressure break and softening;
Step 6:After complete pressure break and softening operation, acid solution remaining in drilling is recycled;
Step 7:Complete a pressure break after, with the superjacent advance of the face to pre-set pressure break apart from when repeat Above-mentioned steps continue to carry out pressure break to igneous rock tight roof.
2. presplitting according to claim 1 and the method for softening igneous rock tight roof, it is characterised in that:Step 1 institute is really The property and composition situation of fixed exploiting field coal rock layer include intrusion layer position and the thickness of igneous rock;The physical mechanics property of interlayer rock stratum Matter includes the fundamental strength parameter of igneous rock:Compression strength, tensile strength and shearing strength;Petrology characteristic includes igneous rock Mineral composition and its content, the content including carbonate mineral.
3. presplitting according to claim 1 and the method for softening igneous rock tight roof, it is characterised in that:Step 2 determines Drilling depth be upper and lower two layers of coal interlamellar spacing, bore diameter be 75~100mm.
4. presplitting according to claim 1 and the method for softening igneous rock tight roof, it is characterised in that:Step 2 determines The concentration of acid solution need to be determined according to the content of carbonate mineral contained in igneous rock, and carbonate mineral in igneous rock Content can be obtained by X-ray diffraction analysis.
5. presplitting according to claim 1 and the method for softening igneous rock tight roof, it is characterised in that:The spacing of wells by Equation below determines:
In formula:p0For stent ultimate strength allowed to bear;LkFor the stent distance of face roof under control;M is makees top plate thickness;γ is balkstone Unit weight.
6. presplitting according to claim 1 and the method for softening igneous rock tight roof, it is characterised in that:Step 3 pressure break The pressure that pump provides determines that the pressure is determined by the following formula according to the intensity and its residing layer position of igneous rock:
Wherein:pbFor the fracture pressure for the palisades that drill, MPa;
poFor the pore pressure of rock, MPa;
efFor the intensity of tensile stress of rock, i.e. rupture stress, MPa;
ehFor stratum minimum horizontal principal stress, MPa;
eHFor stratum maximum horizontal principal stress, MPa;
Z is poroelasticity constant;
OcFor the contact porosity of rock, %;
These parameters are measured by laboratory test;
Calculating gained igneous rock tight roof according to the formula allows broken mechanics to be the spacing of wells.
7. presplitting according to claim 1 and the method for softening igneous rock tight roof, it is characterised in that:Step 5 is related to Fracture acidizing unit device preserved by fracturing pump, digital control system, pipe-line system and fracturing fluid form;By fracturing pump by concentration HCl solution for 15%~28% is pumped into drilling, sets pumping pressure, carries out pressure break to igneous rock tight roof, simultaneously Softening igneous rock is reacted with what carbonate mineral contained in igneous rock carried out using acid solution, it will be in drilling after completion pressure break Acid solution recycled.
CN201610659540.XA 2016-08-11 2016-08-11 A kind of presplitting and the method for softening igneous rock tight roof CN106285679B (en)

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