CN102797448B - Retreating sectional type hydraulic cracking method - Google Patents
Retreating sectional type hydraulic cracking method Download PDFInfo
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- CN102797448B CN102797448B CN201210316418.4A CN201210316418A CN102797448B CN 102797448 B CN102797448 B CN 102797448B CN 201210316418 A CN201210316418 A CN 201210316418A CN 102797448 B CN102797448 B CN 102797448B
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Abstract
The invention relates to a retreating sectional type hydraulic cracking method. In the invention, a mounting rod specially used for cracking is adopted to convey a hole sealer to a set position of a cracking hole, hole sealing is carried out, and the hydraulic cracking method is implemented for one time; after cracking is completed, the hole sealer is externally moved at a set step pitch towards an orifice direction, and the hydraulic cracking method is continuously implemented; and with such a repeated way till the hole sealer is moved to the minimum hole sealing depth of the cracking hole, the integral retreating sectional type hydraulic cracking method is completed. With the retreating sectional type hydraulic cracking method disclosed by the invention, the defect of nonuniform deep drill hole cracking gap caused by deep hole cracking is effectively overcome, and therefore, the problem of external denseness and internal sparseness of the cracking gap is solved; the cracking position of a crack inside a drill hole is controlled, and the extended range of the cracking gap is enlarged, and therefore, the stress cracking effect of the retreating sectional type hydraulic cracking method for a deep hole is especially outstandingly improved; if the retreating sectional type hydraulic cracking method is simultaneously adopted for multiple holes, the cracking position of the crack inside the drill hole and the extending direction of the cracking gap can be effectively controlled, and therefore, the effect of directional cracking is achieved; and the retreating sectional type hydraulic cracking method has the advantages of simplicity, convenience for construction, easy operation, safety and reliability.
Description
Technical field
The present invention relates to a kind of hydraulic fracture method, especially a kind of retrogressing segmented hydraulic fracture method.
Background technology
Hydraulic fracture technology is applied in petroleum works the earliest to improve oil-poor well yield, is widely used in the fields such as Modern Coal exploitation, Development of Geothermal Resources, nuclear waste storage at present, demonstrates industrial application value widely.By means of the basic conception of hydraulic fracture, research and development coal and rock hydraulic fracture weakens with anti-reflection technology as one of key technology solving coal mining CONTROL OF STRATA MOVEMENT and gas preventing and control.
In the process of conventional coal seam hydraulic fracture, the expansion due to hydraulic fracture is subject to impact, the expansion table emersion time in crack and the inhomogeneities in space of geostatic stress and coal body hugger-pore system.Especially at highly gassy mine, the inhomogeneities of hydraulic fracture expansion causes gas to drive uneven basic reason.The coal body region gas that the inhomogeneities of hydraulic fracture spatial spread can make hydraulic pressure gradient little drives weak effect, even cannot drive, cause gas to be detained; The inhomogeneities of hydraulic fracture spatial spread easily blocks the migration pathway of gas in coal body, even trap coal gas, causes local gas content and pressure to raise.Conventional hydraulic fracturing process also can cause stress redistribution in coal body simultaneously, and stress raisers also can affect the permeability of coal body, and then unfavorable to gas migration.In addition, because the propagation direction in coal and rock hydrofracturing crack affects by fracturing boring stress field around, fracturing scope is by the impact of drilling depth, water injection pressure and water filling discharge capacity; Especially in deep hole hydraulic fracture method, the hydraulic pressure decay of fracturing boring deep is serious, cause the hydraulic fracture of deep hole fracturing to present " outer close interior dredge " and extremely uneven, in conventional hydraulic fracturing method, the single fracturing of single hole or porous is difficult to meet field hydraulic fracturing effect.
Summary of the invention
Technical problem: the object of the invention is the weak point overcome in prior art, provides a kind of retrogressing segmented hydraulic fracture method that method is simple, effective, uniformity is good, safe and reliable.
Technical scheme: retrogressing multisection type hydraulic fracture method of the present invention, comprises the steps:
A. be the fracturing boring of 4 ~ 200 m by rig multiple degree of depth of constructing one by one in the coal and rock of pre-exploitation;
B. adopting many continued accesses fracturing together special mounting rod hole packer to be sent into respectively multiple fracturing boring interior extremely distance aperture degree of depth is that 3 ~ 160 m places carry out sealing of hole; The special mounting rod connected mode of described continued access fracturing is together for being threaded or snap joint connection;
C., the water injecting pipeline that mounting rod special with fracturing is connected is installed respectively at the aperture place that multiple fracturing is holed, on the water injecting pipeline at each fracturing drilling orifice place, stop valve and pressure meter are installed simultaneously, utilize equivalent current divider to be linked together by each water injecting pipeline, be connected with water injecting pump by equivalent current divider;
D. open water injecting pump, regulate equivalent current divider, water filling in the sealing of hole of being holed to one or more fracturing continuously by the special mounting rod of fracturing, carries out a circulation hydraulic fracturing;
When the water injection pressure monitoring one or more water injecting pipeline hydraulic fracture from pressure meter is less than 1 MPa, close the stop valve on one or more water injecting pipeline;
When the water injection pressure monitoring all water injecting pipeline hydraulic fractures from pressure meter is all less than 1 MPa, closes water injecting pump, complete this circulation hydraulic fracturing;
E. shift out step pitch 1 ~ 15 m by after hole packer release to fracturing drilling orifice direction, repeat steps d, again carry out a circulation hydraulic fracturing,
F. repeat step e many times, until hole packer retreats carry out last circulation hydraulic fracturing to the aperture degree of depth 1 ~ 15 m place apart from fracturing boring, complete and retreat segmented hydraulic fracture.
Beneficial effect: the present invention is conducive to the extraction of tight roof and the top reduction of coal, the transfer of stress field of the surrounding rock and coal-bed gas; Excellent to effect such as dynamic disaster such as control impulsion pressure, coal and gas prominent etc., single hole or porous is adopted to retreat segmented hydraulic fracture method, the crack starter location in crack and propagation direction and scope can be controlled in fracturing boring, and then ensures the uniformity of hydraulic fracture expansion.Especially at highly gassy mine, implementation result of the present invention is more obvious.This method can realize the transformation to Coal-body Structure, improves the gas permeability of coal and rock.For the coal seam of gas permeability, water under high pressure drives a large amount of free gas of free state from the crack, hole of coal body, the free gas in coal seam is ejected in advance by multiple gas pumping holes of water injection hole periphery, both the gas pressure in coal seam had been reduced, reduce outburst hazard, greatly reduce again the peak value of Gas during driving coal breakage, effectively prevent driving space gas exceeding limit.Meanwhile, coal body produces internal displacement and structural deterioration under the effect of water under high pressure, can reduce coal body elasticity, increases coal body plasticity, changes the stress state of coal body, reaches the effect of release and firedamp drainage, thus play protrusion-dispelling effect.In addition, hydraulic fracture and gas pumping hole can be utilized to carry out the moistening coal body of static pressure water filling to coal seam according to requirement of engineering after gas pumping is complete, water plays obvious inhibitory action to Gas, the desorption rate of residual gas in coal body can be reduced, gush out speed and the outburst amount of gas in corresponding reduction coal body; Coal body can be softened further simultaneously, increase plasticity and the cohesive strength of coal body, reduce coal and gas prominent further dangerous, reach the object of multistage, even, effective, safe fracturing.Its method is simple, and easy construction is safe and reliable, effective, has practicality widely.
Accompanying drawing explanation
Fig. 1 is that hydraulic fracture of the present invention arranges schematic diagram;
Fig. 2 (a) is the hydraulic fracture special mounting rod screw connection structure schematic diagram in the present invention.
Fig. 2 (b) is the hydraulic fracture special mounting rod fast connecting joint structural representation in the present invention.
In figure: 1-water injecting pump, 2-coal and rock, the special mounting rod of 3-fracturing, 3-1-mounting rod Special connecting joint, 3-2-mounting rod external screw thread connection end, 3-3-pipe bar, the built-in sealing ring of 3-4-, 3-5-snap joint connects male, and 3-6-snap joint connects female, 4-hole packer, 5-stop valve, 6-pressure meter, 7-equivalent current divider, 8-water injecting pipeline, 9-fracturing is holed.
Detailed description of the invention
Below in conjunction with accompanying drawing, embodiments of the invention are further described:
The present invention a kind of retreats segmented hydraulic fracture method, is first the fracturing boring 9 of 4 ~ 200 m by rig multiple degree of depth of constructing one by one in the coal and rock 2 of pre-exploitation, and it 9 is the straight angle or elevation angle linear arrangement that multiple fracturing is holed; Then adopt the special mounting rod of many continued accesses fracturing together 3 to be sent into respectively by hole packer 4 to being that 3 ~ 160 m places carry out sealing of hole apart from the aperture degree of depth in multiple fracturing boring 9, described hole packer 4 adopts capsule fracturing hole packer or capsule fracturing packer.Described continued access fracturing together special mounting rod 3 connected mode is for being threaded or snap joint connection; The water injecting pipeline 8 that mounting rod 3 special with fracturing is connected is installed respectively at the aperture place of multiple fracturing boring 9, simultaneously each fracturing hole 9 aperture places water injecting pipeline 8 on stop valve 5 and pressure meter 6 are installed, utilize equivalent current divider 7 to be linked together by each water injecting pipeline 8, be connected with water injecting pump 1 by equivalent current divider 7.
During work, open water injecting pump 1, regulate equivalent current divider 7 continuously to water filling in the sealing of hole of one or more fracturing boring 9, carry out a circulation hydraulic fracturing; When the water injection pressure monitoring one or more water injecting pipeline 8 hydraulic fracture from pressure meter 6 is less than 1 MPa, close the stop valve 5 on one or more water injecting pipeline 8; When the water injection pressure monitoring all water injecting pipeline 8 hydraulic fractures from pressure meter 6 is all less than 1 MPa, closes water injecting pump 1, complete a circulation hydraulic fracturing; Step pitch 1 ~ 15 m is shifted out to fracturing 9 directions, aperture of holing by after hole packer 4 release, repeat water filling in one or more fracturing boring 9, shift out after hole packer 4 release to direction, aperture again afterwards, go round and begin again, carry out repeatedly circulation hydraulic fracturing, until hole packer 4 retreats carry out last circulation hydraulic fracturing to the aperture degree of depth 1 ~ 15 m place apart from fracturing boring 9, exit hole packer 4, complete and retreat segmented hydraulic fracture.
embodiment one:certain pit coal layer is thick about 2.51 m on average, buried depth 800 about m, and this ocurrence of coal seam is stablized, and structure is simple, and seam inclination is about 0 ° ~ 6 °, average 4 °.Tax is stored in group middle and lower part, Shanxi, lower distance Taiyuan group top limestone about 50 m, seat earth sandstone 36.6 m, upper apart from K
4aluminium matter mud stone 51.51 m, top board is Sandy Silt or sandstone, and base plate is Sandy Silt and siltstone, and coal seam is more stable.Gas bearing capacity is about 11.15m
3/ t, gas pumping radius is 5 m, and Permeability Coefficent in Coal Seam is 0.0861 m
3/ (MPa
2.d).Coal seam Failure type belongs to III ~ IV class coal, relative gas pressure 1.12 ~ 1.7 MPa, and solid coefficient is 0.22 ~ 0.4059, and the gas diffusion initial speed in coal seam is 12.957 ~ 14.000, and coal seam gas-bearing capacity is 6.15 ~ 17.59 m
3/ t, this coal seam is coal and gas prominent coal seam, and coal dust does not have explosion hazard.
According to on-site actual situations, be 0 °, fan-shaped, plane fracturing boring 9 at driving face 3 inclination angles of meeting head on to construct along coal seam, i.e. straight angle linear arrangement.Bore diameter is 75 mm, hole depth 200 m, the spacing of wells is 2.0 m, adopt and select single hole to carry out hydraulic fracture mode to carry out coal seam extinction and gas is driven, be that the capsule fracturing packer 4 of φ 75 mm is sent in a fracturing boring 9 to being that 160 m places carry out sealing of hole apart from the aperture degree of depth by diameter by the special mounting rod 3 of fracturing of many continued accesses snap joint connected mode together, the special mounting rod 3 of fracturing of described snap joint connected mode is by pipe bar 3-3, the snap joint being located at pipe bar 3-3 side connects male 3-5 and is connected female 3-6 formation with the snap joint of opposite side, snap joint connection female 3-6 is set with sealing ring 3-4, the water injecting pipeline 8 that the special mounting rod 3 of the fracturing be connected with snap joint is connected is installed respectively at the aperture place of this fracturing boring 9, simultaneously this fracturing hole 9 aperture places water injecting pipeline 8 on stop valve 5 and pressure meter 6 are installed, utilize equivalent current divider 7 to be linked together by each water injecting pipeline 8, be connected with water injecting pump 1 by equivalent current divider 7.
As shown in Figure 1, opening water injecting pump 1, by regulating equivalent current divider 7 continuously to water filling in a fracturing boring 9, carrying out a circulation hydraulic fracturing; When the water injection pressure monitoring this water injecting pipeline 8 hydraulic fracture from pressure meter 6 is less than 1 MPa, closes water injecting pump 1, complete this circulation hydraulic fracturing; Step pitch 15 m is shifted out to fracturing 9 directions, aperture of holing by after the release of capsule fracturing packer 4, repeat above step, again carry out a circulation hydraulic fracturing, go round and begin again, until capsule fracturing packer 4 retreats carry out last circulation hydraulic fracturing to the aperture degree of depth 15 m place apart from fracturing boring 9, exit capsule fracturing packer 4, complete and retreat segmented hydraulic fracture.
embodiment two:certain pit coal layer average thickness 1.5 m, inclination angle average out to 6 °, seam hardness
f=2; Immediate roof is light grey medium sandstone, average thickness 2.28 m; Old top is grey black Sandy Silt, average thickness 5.33 m.According to on-site actual situations, need to construct one by one the hydraulic fracture boring 9 that 90 °, several inclination angles, linear, vertical top board upwards arrange by Mian Ce lane side of taking over job at air way first advance 30 m, i.e. elevation angle linear arrangement.Fracturing bore diameter is 32 mm, hole depth 4 m, and the spacing of wells is 0.5 m, successively along the construction of advance of the face direction, carries out the directed joint-cutting gob side entry retaining of top board.Adopting the special mounting rod of fracturing 3 of many continued accesses thread connecting mode together the capsule fracturing hole packer 4 of φ 32 mm to be sent into respectively multiple fracturing boring 9 interior extremely distance aperture degree of depth is that 3 m places carry out sealing of hole, the special mounting rod 3 of fracturing of described thread connecting mode comprises pipe bar 3-3, the both sides of pipe bar 3-3 are screwed pipe 3-2, screwed pipe 3-2 is equipped with the mounting rod Special connecting joint 3-1 of next screwed pipe of continued access 3-2, built-in sealing ring 3-4 is equipped with at the middle part of mounting rod Special connecting joint 3-1; The water injecting pipeline 8 that mounting rod 3 special with the fracturing of thread connecting mode is connected is installed respectively at the aperture place of multiple fracturing boring 9, simultaneously each fracturing hole 9 aperture places water injecting pipeline 8 on stop valve 5 and pressure meter 6 are installed, utilize equivalent current divider 7 to be linked together by each water injecting pipeline 8, be connected with water injecting pump 1 by equivalent current divider 7.
Open water injecting pump 1, regulate equivalent current divider 7 continuously to water filling in multiple fracturing boring 9, carry out a circulation hydraulic fracturing; When the water injection pressure monitoring one or more water injecting pipeline 8 hydraulic fracture from pressure meter 6 is less than 1 MPa, close the stop valve 5 on one or more water injecting pipeline 8; When the water injection pressure monitoring all water injecting pipeline 8 hydraulic fractures from pressure meter 6 is all less than 1 MPa, closes water injecting pump 1, complete this circulation hydraulic fracturing; Step pitch 1 m is shifted out to fracturing 9 directions, aperture of holing by after the release of capsule fracturing hole packer 4, repeat above step, again carry out a circulation hydraulic fracturing, until capsule fracturing hole packer 4 retreats carry out last circulation hydraulic fracturing to the aperture degree of depth 1 m place apart from fracturing boring 9, exit capsule fracturing hole packer 4, complete and retreat segmented hydraulic fracture.
Claims (1)
1. retreat a segmented hydraulic fracture method, it is characterized in that comprising the steps:
A. be fracturing boring (9) of 4 ~ 200 m by rig multiple degree of depth of constructing one by one in the coal and rock (2) of pre-exploitation;
B. adopt the special mounting rod of many continued accesses fracturing together (3) to be sent into respectively by hole packer (4) to being that 3 ~ 160 m places carry out sealing of hole apart from the aperture degree of depth in multiple fracturing boring (9), the special mounting rod of described continued access fracturing together (3) connected mode is for being threaded or snap joint connection;
C., the water injecting pipeline (8) that mounting rod (3) special with fracturing is connected is installed respectively at the aperture place of multiple fracturing boring (9), on the water injecting pipeline (8) at each fracturing boring (9) aperture place, stop valve (5) and pressure meter (6) are installed simultaneously, utilize equivalent current divider (7) to be linked together by each water injecting pipeline (8), be connected with water injecting pump (1) by equivalent current divider (7);
D. open water injecting pump (1), regulate equivalent current divider (7), by the special mounting rod of fracturing (3) continuously to water filling in the sealing of hole of one or more fracturing boring (9), carry out a circulation hydraulic fracturing;
When the water injection pressure monitoring one or more water injecting pipeline (8) hydraulic fracture from pressure meter (6) is less than 1 MPa, close the stop valve (5) on one or more water injecting pipeline (8);
When the water injection pressure monitoring all water injecting pipelines (8) hydraulic fracture from pressure meter (6) is all less than 1 MPa, closes water injecting pump (1), complete this circulation hydraulic fracturing;
E. shift out step pitch 1 ~ 15 m by after hole packer (4) release to fracturing boring (9) direction, aperture, repeat steps d, again carry out a circulation hydraulic fracturing;
F. repeat step e many times, until hole packer (4) retreats carry out last circulation hydraulic fracturing to the aperture degree of depth 1 ~ 15 m place apart from fracturing boring (9), complete and retreat segmented hydraulic fracture.
2. retrogressing segmented hydraulic fracture method according to claim 1, is characterized in that: described multiple fracturing boring (9) constructed one by one in the coal and rock (2) of pre-exploitation is the straight angle or elevation angle linear arrangement.
3. retrogressing segmented hydraulic fracture method according to claim 1, it is characterized in that: the special mounting rod of fracturing (3) of described thread connecting mode comprises pipe bar (3-3), the both sides of pipe bar (3-3) are screwed pipe (3-2), screwed pipe (3-2) are equipped with the mounting rod Special connecting joint (3-1) of next screwed pipe of continued access (3-2); Built-in sealing ring (3-4) is equipped with at the middle part of mounting rod Special connecting joint (3-1).
4. retrogressing segmented hydraulic fracture method according to claim 1, is characterized in that: described hole packer (4) adopts capsule fracturing hole packer.
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| CN103541711B (en) * | 2013-10-21 | 2016-04-13 | 中国矿业大学 | Xuan Ding small-bore, coal-face termination hydraulic fracture control method |
| CN108678747B (en) * | 2018-04-28 | 2019-08-30 | 中国矿业大学 | A kind of method and apparatus of pulsed water fracturing control Top coal caving characteristic |
| CN111322048B (en) * | 2020-02-21 | 2021-11-09 | 中煤科工集团西安研究院有限公司 | Hard roof rock burst subsection direction-control fracturing treatment method |
| CN111322076A (en) * | 2020-03-03 | 2020-06-23 | 中国矿业大学 | Method for forming roadway scour-prevention weak structure through coal rock hydraulic fracturing |
Citations (3)
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|---|---|---|---|---|
| CN201953367U (en) * | 2010-12-30 | 2011-08-31 | 河南理工大学 | Underground drilling and pressurizing integrated staged fracturing device |
| CN102392677A (en) * | 2011-10-21 | 2012-03-28 | 河南煤业化工集团研究院有限责任公司 | Permeability improvement technology for coal bed gas reservoir cap by using three-dimensional fracture network modification |
| CN102628352A (en) * | 2012-04-23 | 2012-08-08 | 中国矿业大学 | Multi-section fixed point hydraulic fracturing method |
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| US7404441B2 (en) * | 2006-02-27 | 2008-07-29 | Geosierra, Llc | Hydraulic feature initiation and propagation control in unconsolidated and weakly cemented sediments |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201953367U (en) * | 2010-12-30 | 2011-08-31 | 河南理工大学 | Underground drilling and pressurizing integrated staged fracturing device |
| CN102392677A (en) * | 2011-10-21 | 2012-03-28 | 河南煤业化工集团研究院有限责任公司 | Permeability improvement technology for coal bed gas reservoir cap by using three-dimensional fracture network modification |
| CN102628352A (en) * | 2012-04-23 | 2012-08-08 | 中国矿业大学 | Multi-section fixed point hydraulic fracturing method |
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