Directional hydraulic fracturing top coal method for weakening between fully mechanized coal face frameArt
The present invention relates to a kind of method that top-coal caving face coal weakens, directional hydraulic fracturing between particularly a kind of fully mechanized coal face frameTop coal method for weakening.
Background technology
Longwall top coal caving technology is because of features such as its production capacity are big, efficiency is high, profitable, it has also become the head of high and extra-high seam miningChoosing method, although Longwall top coal caving technology is widely used the most at home, but knowable to longwall top coal caving is put into practice, the rate of recoveryThe low common problem being still fully mechanized coal face, the fully mechanized coal face relatively big in particular for top coal Polodyakonov coefficient coefficient, toughness is strongerFor, this phenomenon is particularly evident.Longwall top-coal caving weakens technology at present mainly has: shallow blasting, work between work face frameThe methods such as deep hole blasting in face crossheading or technique lane, ahead work face water filling softening.Wherein work shallow blasting between face frame due to weakThe substantivity changed, top coal weakens effect clearly, but in view of its safety issue, this kind of method is prohibited by country；In return airway or technique lane, deep hole blasting cost height, poor controllability, be easily generated a large amount of dust during blowing out, and deteriorates workFace environment, easily causes gas explosion in highly gassy mine, easily causes roof fall accident at loose roof working face；Working face surpassesFront water filling softening technology water injection time is longer, water injection rate is relatively big, and for the coal body that, porosity little to infiltration coefficient is low, effect is poor.The top coal method for weakening that the present invention provides can realize the orientation of coal specific region, complete top, fixed point above support and weaken, and has intoThis is low, controllability good, effect outstanding feature, and working face top-coal recovery rate can be significantly improved.
Summary of the invention
The technical problem to be solved is for above-mentioned the deficiencies in the prior art, it is provided that a kind of low cost, controllability be good,Orientation top coal method for weakening between effect significant fully mechanized coal face frame.
The technical solution adopted for the present invention to solve the technical problems comprises the steps:
(1) utilize intelligent television borehole imaging technology, crushing voerhead coal state above support is detected, determines above support completeCoal region, whole top；
(2) using pneumatically or hydraulically jumbolter vertical or fracturing boring that tilts to construct between fully mechanized coal face support frame, boring is deepSpend to coal region, complete top；
(3) exit drilling rod, change slotting drill bit, and import at the bottom of drilling hole, rotary rig, manually slot；
(4) take out drilling rod and slotting drill bit, high pressure sealing formula mounting rod is connected with hydraulic expansion type high pressure hole packer, and by waterPower expansion type high pressure hole packer is sent at slotting position 10cm；
(5) high-pressure rubber pipe, stop valve and high pressure sealing formula mounting rod being connected, the high-pressure rubber pipe other end connects high-pressure pump；
(6) opening high-pressure pump, open stop valve, inject water under high pressure by high-pressure rubber pipe in fracturing is holed, hydraulic expansion type is highPressure hole packer starts to expand, it is achieved sealing of hole and directional fracturing；
(7) when on hydrofracturing pipeline, Pressure gauge numerical value presents bust trend, wedge-shaped slot tip ruptures, and forms Oriented Fracture,Water under high pressure, along the continuous outward expansion of this Oriented Fracture, reaches 12mim～15mim when the pressure break time, and fracturing radius interior orientation crack is passed throughLogical, close high-pressure pump and stop valve, stop high-pressure hydraulic pressure break；
(8) taking out hydraulic expansion type high pressure hole packer, repeating above-mentioned (2)～(7) process, until completing all borehole fracturings.
Drilling rod used by step (2) described construction drill isDrill rod special, boring aperture isThe spacing of wellsFor 15m.
Step (4) described high pressure sealing formula mounting rod is a diameter ofHydraulic expansion type high pressure hole packer is a diameter of
Step (6) described hydraulic expansion type high pressure hole packer expands the pressure of sealing of hole and is not less than 4MPa, and high-pressure pump fracturing pressure existsMore than 20MPa.
The present invention realizes the general principle that between fully mechanized coal face frame, directional hydraulic fracturing top coal weakens: utilize water under high pressure to complete topThe wedge-shaped slot that coal region artificially manufactures is oriented pressure break, under water under high pressure effect, produces stress collection drastically at wedge-shaped slot tipIn, when wedge-shaped slot tip concentrated stress exceedes the fracturing intensity of coal body, coal body will be first in wedge-shaped slot tip fracturing, and at waterExtend along this fracture propagation under the continuation effect of pressure, the most through with adjacent pressure break porous dehiscence gap, thus formed in coal region, complete topPlane of weakness, reduces the thickness of layering, reduces intensity and the integrality in coal seam, the final smooth recovery realizing top coal.
The invention has the beneficial effects as follows, to possess between the fully mechanized coal face frame of " low cost, controllability are good, effect is notable " featureDirectional hydraulic fracturing top coal weakens technology, solve the cost height of current top-coal caving face coal reductions technology existence, poor controllability,The problem of DeGrain, improves the caving ability of top-coal caving face coal, it is ensured that the high-recovery exploitation of fully mechanized coal face.
Accompanying drawing explanation
The present invention is further described with embodiment below in conjunction with the accompanying drawings.
Fig. 1 is that working face directional hydraulic fracturing top of the present invention coal weakens A-A profile
Fig. 2 is working face directional hydraulic fracturing top of the present invention coal weakened planes figure
1-wedge-shaped slot in Fig. 1；2-Oriented Fracture；3-fracturing is holed；4-hydraulic expansion type high pressure hole packer；5-supportTop, top coal；6-integrated caving hydraulic support；7-high pressure sealing formula mounting rod；8-stop valve；9-Pressure gauge；10-high-pressure gluePipe
3-fracturing boring in Fig. 2；6-integrated caving hydraulic support；11-fully mechanized coal face
Detailed description of the invention
Below in conjunction with accompanying drawing, embodiments of the invention are further described:
Certain pit coal layer average thickness 13.7m, for middle hard coal seam, seam inclination 1～3 °, uses mining technology to carry out back production,Coal cutting height 3.2m, average caving coal height 10.5m, before directional hydraulic fracturing, working face top-coal recovery rate is 40%～50%, rootUnderstanding according to intelligent television imaging technique detection analysis, above force piece, more than 4.5m top coal integrality is preferable.According to sceneActual conditions, for completely coal region, top weakening more than support 4.5m, put comprehensive initially with pneumatically or hydraulically jumbolterVertical construction fracturing boring (3) between working face (11) interior integrated caving hydraulic support (6) frame, spacing of wells 15m, bore diameter is50mm, drilling depth 6.5m；Next exits drilling rod, changes slotting drill bit, and imports at the bottom of drilling hole, and rotary rig is formedWedge-shaped slot (1)；Take out drilling rod and slotting drill bit subsequently, by high pressure sealing formula mounting rod (7) and hydraulic expansion type high pressure hole packer(4) connect, and hydraulic expansion type high pressure hole packer (4) is sent at slotting position 10cm；Then by high-pressure rubber pipe (10),Pressure gauge (9), stop valve (8) and high pressure sealing formula mounting rod (7) are connected, and high-pressure rubber pipe (10) other end connects heightPress pump；Open high-pressure pump, open stop valve (8), in fracturing boring (3), inject water under high pressure by high-pressure rubber pipe (10),Hydraulic expansion type high pressure hole packer (4) starts expansion and realizes sealing of hole and directional fracturing；When Pressure gauge (9) numerical value in fracturing pipelineDuring bust, wedge-shaped slot (1) tip ruptures, and forms Oriented Fracture (2), water under high pressure along Oriented Fracture (2) constantly outward expansion,Reaching 12mim～15mim when the pressure break time, in fracturing radius, crack is through, closes high-pressure pump and stop valve (8), stops high pressureFracturing；Finally taking out hydraulic expansion type high pressure hole packer (4), repeat above step, again carrying out drilling depth is 8.5mPosition directional fracturing.