CN117386447A - Staged fracturing grouting curtain device and method for advanced drilling of water bearing layer on top plate of coal bed - Google Patents
Staged fracturing grouting curtain device and method for advanced drilling of water bearing layer on top plate of coal bed Download PDFInfo
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- 239000003245 coal Substances 0.000 title claims abstract description 71
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 71
- 238000005553 drilling Methods 0.000 title claims abstract description 44
- 238000000034 method Methods 0.000 title claims description 24
- 238000012856 packing Methods 0.000 claims abstract description 11
- 238000003825 pressing Methods 0.000 claims description 29
- 238000002347 injection Methods 0.000 claims description 20
- 239000007924 injection Substances 0.000 claims description 20
- 238000013461 design Methods 0.000 claims description 13
- 239000004576 sand Substances 0.000 claims description 11
- 239000012530 fluid Substances 0.000 claims description 9
- 238000006073 displacement reaction Methods 0.000 claims description 8
- 239000007788 liquid Substances 0.000 claims description 8
- 239000000654 additive Substances 0.000 claims description 3
- 230000000996 additive effect Effects 0.000 claims description 3
- 230000000844 anti-bacterial effect Effects 0.000 claims description 3
- 239000003899 bactericide agent Substances 0.000 claims description 3
- 238000011010 flushing procedure Methods 0.000 claims description 3
- 238000003801 milling Methods 0.000 claims description 3
- 238000005507 spraying Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 abstract description 11
- 230000009467 reduction Effects 0.000 abstract description 4
- 238000005065 mining Methods 0.000 description 13
- 230000000694 effects Effects 0.000 description 6
- 230000002265 prevention Effects 0.000 description 5
- 238000010276 construction Methods 0.000 description 4
- 230000009466 transformation Effects 0.000 description 4
- 230000000903 blocking effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000003673 groundwater Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000011440 grout Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
- E02D3/12—Consolidating by placing solidifying or pore-filling substances in the soil
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/13—Methods or devices for cementing, for plugging holes, crevices or the like
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
- E21B43/267—Methods for stimulating production by forming crevices or fractures reinforcing fractures by propping
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B7/00—Special methods or apparatus for drilling
- E21B7/04—Directional drilling
- E21B7/046—Directional drilling horizontal drilling
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B7/00—Special methods or apparatus for drilling
- E21B7/18—Drilling by liquid or gas jets, with or without entrained pellets
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Abstract
The invention discloses a system for advanced drilling staged fracturing grouting curtain of a coal seam roof aquifer, which comprises a first releasing device, a lower centralizer, a hydraulic anchor, an upper centralizer, an oil pipe passing packer, an injector, a pressure-retaining packing device and a pressure-guiding falling device which are coaxially connected in sequence from back to front; by arranging a plurality of horizontal branch wells, a relatively continuous water-blocking and water-blocking wall body is formed in the vertical direction, the water-blocking and water-blocking wall body in the roof aquifer is built, the water inflow of the coal face is greatly reduced, the water reduction of the coal face of a mine is realized, the safety production requirement of the mine is ensured, and the advanced productivity of the mine is fully released.
Description
Technical Field
The invention belongs to the technical field of mine water control, relates to advanced drilling staged fracturing, and in particular relates to an advanced drilling staged fracturing grouting curtain device and method for a seam roof aquifer.
Background
The sandstone aquifer water disaster on the coal seam roof is different from the type of water burst of the bottom plate Ort ash and water permeation in the sky, the main water outlet positions are a stope face and a goaf, the water inflow change regularity is obvious, and the method has the characteristics of weak burst, no serious disasters caused under the normal water inflow condition, and the like, but has high water inflow intensity and long duration, so that the normal and safe production of a mine is seriously affected.
After the coal seam is mined, the roof water guide fracture zone develops upwards, and the water-resisting layer is destroyed to influence the roof aquifer, so that aquifer water enters the underground, and mine water burst is caused. Taking the Erdos basin as an example, the sandstone aquifer on the roof of the coal seam is usually mainly composed of sandstone, a mudstone thin layer and a lens body, and the whole aquifer is composed of sandstone, conglomerate and a small amount of mudstone medium, so that the vertical heterogeneity is strong.
Aiming at the characteristics of the roof aquifer, the prevention and control methods such as underground drainage, height-limited exploitation, height control of the water guide fracture zone and the like are generally adopted to ensure that the water guide fracture zone does not or a small amount of water guide fracture zone does not reach the roof aquifer, but the prevention and control methods belong to passive prevention and control measures, so that the efficient production of a mine can be directly limited greatly, the coal recovery rate is reduced, and coal resources are wasted. Meanwhile, as the modern coal mining degree of the mine is high and the prevention and control effect is not ideal, an effective roof-covering aquifer prevention and control technology and method cannot be established at present.
In summary, the existing technology for preventing and treating the coal seam roof water is difficult to meet the safety production requirements of modern mines, and cannot effectively release the advanced productivity of the mines.
Disclosure of Invention
Aiming at the defects and shortcomings in the prior art, the invention provides a device and a method for advanced drilling staged fracturing grouting curtain of a coal seam roof aquifer, which are used for solving the technical problems that a coal seam roof water control method in the prior art influences coal exploitation efficiency and is difficult to meet mine safety production requirements.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a system for advanced drilling staged fracturing grouting curtain of a coal seam roof aquifer comprises a first releasing device, a lower centralizer, a hydraulic anchor, an upper centralizer, an oil pipe passing packer, an injector, a pressure-retaining packer and a pressure guide stripper which are coaxially connected in sequence from back to front;
the pressure maintaining and packing device comprises a pressure maintaining and packing device releasing device and a built-in one-way valve which are coaxially communicated from back to front, and a leakage-proof device packer is sleeved outside the built-in one-way valve.
The invention also has the following technical characteristics:
specifically, a connecting device is further arranged between the hydraulic anchor and the upper centralizer.
The method is realized by the aid of the system for the advanced drilling staged fracturing grouting curtain of the coal seam roof aquifer, and comprises the following steps of:
step 1, completing the design of a plurality of branch horizontal wells in a reconstruction area; the design comprises the layout position of each branch horizontal well, all fracturing sections of each branch horizontal well and perforation grouting positions of each fracturing section;
step 2, drilling of the first branch horizontal well is completed;
step 3, using a continuous oil pipe to lower a coal seam roof aquifer advanced drilling staged fracturing grouting curtain to a perforation grouting position of a first fracturing section of a first branch horizontal well by using a system, and completing hydraulic injection operation of the first fracturing section of the first branch horizontal well;
step 4, completing fracturing operation of a first fracturing section of the first branch horizontal well by adopting ground fracturing equipment to form a first crack space body;
step 5, completing high-pressure grouting operation on the first crack space body by adopting ground grouting equipment, and obtaining a first grouting modified crack filling body after the grouting operation is finished;
step 6, lifting the continuous oil pipe, continuously pressurizing to separate the packer from the pressure-maintaining packer, completing setting of the packer by the leak-proof device, leaving the pressure-maintaining packer in the first branch horizontal well, and then lifting out the advanced drilling staged fracturing grouting curtain of the water-bearing layer of the coal seam roof by using the system;
step 7, after the first grouting reconstruction crack filling body is coagulated, drilling down to carry out milling operation on the pressure maintaining packing device, and then completing flushing operation on the branch horizontal well to complete sectional fracturing reconstruction grouting operation of a first fracturing section of the first branch horizontal well;
step 8, analogizing in sequence, repeating the steps 3 to 7, and completing the sectional fracturing reconstruction grouting operation of the residual fracturing section of the first branch horizontal well;
and 9, repeating the steps 2 to 8 by analogy, and completing the sectional fracturing reconstruction grouting operation of all the branch horizontal wells.
Further, the vertical distance between adjacent branch horizontal wells in the plurality of branch horizontal wells in step 1 is 50-80 meters.
Further, the horizontal distance of the ith fracturing stage of the adjacent branch horizontal well is 20-40 meters, wherein i is more than or equal to 1.
Further, the design of the adjacent branch horizontal wells meets the following conditions: in the vertical direction, the lowest point of the ith fracturing crack of the upper branch horizontal well is lower than the highest point of the ith fracturing crack of the lower branch horizontal well, and an included angle between a connecting line between the highest point of the ith fracturing crack of the lower branch horizontal well and the lowest point of the ith fracturing crack of the upper branch horizontal well and an extension line of the ith fracturing crack of the lower branch horizontal well is 45-90 degrees.
Further, the hydraulic jetting operation for completing the first fracturing section of the first branch horizontal well in the step 3 specifically includes the following substeps:
3.1, lowering a coal seam roof aquifer advanced drilling staged fracturing grouting curtain system to a perforation grouting position of a first fracturing stage of a branch horizontal well by using a continuous oil pipe, and performing injection operation at the perforation grouting position by using an injector, wherein the injection operation adopts a large-displacement and circumferential perforation mode, and the injection displacement is 2.0-2.5 m 3 The spraying liquid is clean water;
step 3.2, lifting the continuous oil pipe for 20-25 meters after the injection operation is finished;
step 3.3, pressing the ground, and after the set first pressing pressure is reached, opening the hydraulic anchor and then setting on the well wall; continuously pressing until reaching a set second pressing pressure, and realizing pressure setting after expanding the oil pipe passing packer; after continuing to press until reaching the set third pressing pressure, the leakage-proof device packer is permanently set on the well wall; and continuously pressing until the set fourth pressing pressure is reached, then disengaging the pressure guide stripper, lifting the system for the advanced drilling staged fracturing grouting curtain of the water-bearing layer of the top plate of the coal seam, and completing the hydraulic injection operation of the first fracturing section of the first branch horizontal well.
Further, in the step 3.3, the first pressing pressure is less than the second pressing pressure is less than the third pressing pressure is less than the fourth pressing pressure.
Furthermore, in the fracturing operation in the step 4, active water fracturing fluid is adopted, medium sand with 20/40 meshes and coarse sand with 16/20 meshes are used as supporting media, and the displacement of the fracturing fluid is 14-16 m 3 Per min, the sand adding strength is 14-18m 3 The ratio of the pre-liquid is more than 80 percent;
the active water fracturing fluid comprises the following components in percentage by mass: 1 to 2 percent of KCl, 0.5 to 1 percent of cleanup additive, 0.5 to 1 percent of bactericide and the balance of water.
Compared with the prior art, the invention has the following technical effects:
(1) The system for advanced drilling staged fracturing grouting curtain of the coal seam roof aquifer can realize perforation, fracturing and grouting integrated operation; and the process pipe column has the advantages of simple structure, flexible construction method, simple operation and high efficiency.
(2) The method can form a stable crack space body in the coal seam roof aquifer, and the formed crack space body is not closed, so that a basic condition is provided for subsequent grouting and water reduction; the grouting reconstruction crack filling body which can be used as a stable water-blocking and water-blocking wall body is formed by grouting, so that the underground water runoff direction of a roof aquifer is changed, and the underground water runoff cannot be flushed to a coal face in a large range; through setting up a plurality of horizontal branch wells, form relative continuous water blocking and water insulating wall in vertical direction, finally established the water blocking and water insulating wall in the roof aquifer, have safe water insulating effect to the coal mining district in the pit, greatly reduced the water inflow of coal face, realize the water reduction of mine coal face, ensured the safe production requirement of mine, fully released the advanced productivity of mine.
Drawings
FIG. 1 is a schematic flow chart of the method of the present invention;
FIG. 2 is a schematic diagram of the system of the present invention;
FIG. 3 is a schematic view of the structure of the pressure-retaining packing device;
FIG. 4 is a schematic view of a plurality of branch horizontal wells of the present invention;
FIG. 5 is a schematic diagram of runoff before modification of a roof aquifer of a coal seam;
FIG. 6 is a schematic diagram of runoff after reconstruction of a roof aquifer of a coal seam.
Reference numerals meaning:
1-first releasing, 2-lower centralizer, 3-hydraulic anchor, 4-upper centralizer, 5-through oil pipe packer, 6-injector, 7-pressure maintaining packer, 8-pressure guiding stripper and 9-connecting device;
11-a first horizontal well group, 12-a second horizontal well group;
121-a first branch horizontal well, 122-a second branch horizontal well;
releasing the pressure maintaining packer, arranging a check valve in the pressure maintaining packer and arranging a packer in the pressure maintaining packer and the pressure maintaining packer in the pressure maintaining packer, wherein the check valve is arranged in the pressure maintaining packer and the pressure maintaining packer is arranged in the pressure maintaining packer;
101-coal bed, 102-roof aquifers.
Detailed Description
The present invention will be described in detail below with reference to the drawings and examples so that those skilled in the art can better understand the present invention. It is to be expressly noted that in the description below, detailed descriptions of known functions and designs are omitted here as perhaps obscuring the present invention.
In the present invention, unless otherwise indicated, terms such as "upper, lower, bottom, and top" are used generally to refer to the definition of the drawing plane of the corresponding drawing, and "inner, outer" are used to refer to the definition of the outline of the corresponding drawing.
The target mining area is a mining area to be treated by water damage, one or more adjacent working surfaces to be treated are generally selected, a treatment boundary is set for the target mining area according to exploration data obtained by earlier exploration, a reconstruction area of a roof aquifer of a coal seam is determined, a plurality of branch horizontal wells for reconstruction are arranged in the roof aquifer of the coal seam in the reconstruction area, a relatively continuous vertical plane-shaped water-blocking wall body is established in the roof aquifer of the coal seam (the thickness is generally 200-600 m), lateral water supply intensity of the water-containing layer is cut off or weakened in the reconstruction area, a vertical sandstone body water-blocking curtain is formed, water inflow of the coal mining area is reduced, roof fissure zones developed after water in the coal mining area is effectively reduced or blocked from entering a mine, and thus safety production of the mine is ensured.
Example 1
According to the technical scheme, as shown in fig. 1 and 2, the embodiment provides a system for advanced drilling staged fracturing grouting curtain of a coal seam roof aquifer, which comprises a first releasing device 1, a lower centralizer 2, a hydraulic anchor 3, an upper centralizer 4, an oil pipe passing packer 5, an injector 6, a pressure maintaining and isolating device 7 and a pressure guiding and isolating device 8 which are coaxially connected and arranged from back to front in sequence;
the pressure maintaining packer device 7 comprises a pressure maintaining packer device releasing device 71 and a built-in one-way valve 72 which are coaxially communicated from back to front, and a leakage-proof device packer 73 is sleeved outside the built-in one-way valve.
The hydraulic anchor 3 is used for improving the stability of underground operation of the whole system, the upper centralizer 4 is used for being matched with a lower centralizer stabilizing device, the oil pipe passing packer 5 is used for sealing a fracturing operation section and a non-fracturing operation section, the fracturing force gathering effect is achieved, the ejector 6 is used for manufacturing stratum weak points, the ejector operation is completed, the pressure maintaining sealing device 7 is used for improving grouting reconstruction to form a water blocking wall effect, slurry is guaranteed not to flow back, and the pressure guiding stripper 8 is used for a grouting operation channel after fracturing is finished.
As a preferred solution of this embodiment, a connection device 9 is further provided between the hydraulic anchor 3 and the upper centralizer 4.
The using process of the device is as follows: the method comprises the steps that a coiled tubing is used for leading the water-bearing layer of a coal seam roof to drill into a staged fracturing grouting curtain in advance, the injection operation is completed by means of an injector 6, the coiled tubing is lifted up after the injection operation is finished, the ground starts to be pressurized, and after the third pressurizing pressure is reached, a leakage-proof device packer 73 is set on a well wall; after the grouting reconstruction operation of the fracturing cracks is completed, lifting the coiled tubing, after the lifting force reaches the falling pressure, releasing the release 71 of the pressure-maintaining packing device to enable the pressure-maintaining packing device 7 to be arranged in a branch horizontal well, and then lifting out other parts of the advanced drilling staged fracturing grouting curtain system for the water-bearing layer of the coal seam roof to complete pressure-maintaining packing of the first fracturing section; due to the action of the built-in one-way valve 72 of the pressure-retaining and isolating device 7d, the grout cannot return into the branch horizontal well, and all grouting can enter the stratum, so that the effectiveness of grouting is ensured.
Example 2
In this embodiment, the roof of the coal seam of a certain coal mine in the Shaanxi long mining area is sandy mudstone and sandstone, the boundary of the coal seam and the roof strata is in an integrated state, the drillability of the roof strata is strong, but the mine is influenced by the massive gushing of roof water, and is identified as a mine of a very complex hydrogeological type, and the gushing water amount is 1000-3000m 3 And/h, seriously threatening the safety production of the underground coal mine, enabling the mine production to be in a high-water damage risk operation state for a long time, severely restricting the efficient mining of the mine, and failing to fully release the mine productivity. .
As shown in fig. 1, the embodiment discloses a method for advanced drilling staged fracturing grouting curtain of a coal seam roof aquifer, which is implemented by a system for advanced drilling staged fracturing grouting curtain of the coal seam roof aquifer provided by embodiment 1, and comprises the following steps:
step 1, determining a reconstruction area of a coal seam roof aquifer according to mining area exploration data acquired in a previous period, and completing design of a plurality of branch horizontal wells arranged in the coal seam roof aquifer in the reconstruction area, wherein the design comprises layout positions of each branch horizontal well, all fracturing sections of each branch horizontal well and perforation grouting positions of each fracturing section;
in this embodiment, as shown in fig. 6, two branch horizontal well groups are designed in the roof aquifer, namely a first horizontal well group 11 and a second horizontal well group 12, and the setting directions of the two branch horizontal well groups are opposite, each branch horizontal well group comprises three branch horizontal wells which are arranged in parallel, the construction direction of each fracturing section of each horizontal branch well is from top to bottom, for several branch horizontal wells on the right side, the construction direction of each fracturing section of each horizontal branch well is from right to left, for several branch horizontal wells on the left side, the construction direction of each fracturing section of each horizontal branch well is from left to right,
as a preferable scheme of the embodiment, in the designed multiple branch horizontal wells, the vertical distance between the adjacent branch horizontal wells is 50-80 meters.
In the prior art, the fracturing displacement (8-12 m 3 Per min), sand ratio (10-14 m 3 And/m) and sand concentration, and the like, and can realize the vertical height control of the fracturing cracks of each fracturing position, thereby ensuring that the vertical spacing between adjacent horizontal wells meets the design requirement.
As shown in FIG. 4, as a preferable scheme of the present embodiment, the horizontal distance of the ith fracturing stage of the adjacent branch horizontal wells is 20 to 40 m, i.e., i.gtoreq.1, that is, the horizontal distance between the 1 st fracturing stage of the first branch horizontal well 121 and the 1 st fracturing stage of the second branch horizontal well 122 is 20 to 40 m, the horizontal distance between the 2 nd fracturing stage of the first branch horizontal well 121 and the 2 nd fracturing stage of the second branch horizontal well 122 is 20 to 40 m, and so on.
The design of the adjacent branch horizontal well meets the following conditions: in the vertical direction, the lowest point of the ith fracturing fracture of the upper branch horizontal well (the first branch horizontal well 121 in this embodiment) is lower than the highest point of the ith fracturing fracture of the lower branch horizontal well (the second branch horizontal well 122 in this embodiment), and the angle between the line between the highest point of the ith fracturing fracture of the lower branch horizontal well (the second branch horizontal well 121 in this embodiment) and the lowest point of the ith fracturing fracture of the upper branch horizontal well (the first branch horizontal well 121 in this embodiment) and the extension line of the ith fracturing fracture of the lower branch horizontal well is 45 ° to 90 °.
The purpose of this design is: intersecting the planar water-blocking walls of the adjacent branch horizontal wells to realize cross verification layout and provide a precedent condition for the establishment of continuous planar water-blocking walls in the treatment area.
Step 2, selecting a well position on the ground according to the design of step 1, drilling a first branch horizontal well 121 for reconstruction of a water-bearing layer of a coal seam roof by means of a drilling tool in a forward drilling mode, and lifting the drilling tool up to lift the well head to the ground.
Step 3, using a continuous oil pipe to lower a coal seam roof aquifer advanced drilling staged fracturing grouting curtain to a perforation grouting position of a first fracturing stage of the first branch horizontal well 121 by using a system, and using an injector to perform injection operation at the perforation grouting position so as to complete hydraulic injection operation of the first fracturing stage of the first branch horizontal well;
the method specifically comprises the following steps:
3.1, lowering a coal seam roof aquifer advanced drilling staged fracturing grouting curtain system to a perforation grouting position of a first fracturing stage of a branch horizontal well by using a continuous oil pipe, and performing injection operation at the perforation grouting position by using an injector, wherein the injection operation adopts a large-displacement and circumferential perforation mode, and the injection displacement is 2.0-2.5 m 3 The spraying liquid is clean water;
step 3.2, lifting the continuous oil pipe for 20-25 meters after the injection operation is finished;
step 3.3, pressing the ground, and after the set first pressing pressure is reached, opening the hydraulic anchor and then setting on the well wall; continuously pressing until reaching a set second pressing pressure, and realizing pressure setting after expanding the oil pipe passing packer; after continuing to press until reaching the set third pressing pressure, the leakage-proof device packer is permanently set on the well wall; and continuously pressing until the set fourth pressing pressure is reached, then disengaging the pressure guide stripper, lifting the system for the advanced drilling staged fracturing grouting curtain of the water-bearing layer of the top plate of the coal seam, and completing the hydraulic injection operation of the first fracturing section of the first branch horizontal well.
Wherein the first pressure is less than the second pressure is less than the third pressure is less than the fourth pressure.
In this embodiment, the first pressing pressure is 10-12 MPa, the second pressing pressure is 16-20 MPa, the third pressing pressure is 22-24 MPa, and the fourth pressing pressure is 26-27 MPa.
Step 4, completing fracturing operation of a first fracturing section of the first branch horizontal well by adopting ground fracturing equipment to form a first crack space body;
in the fracturing operation of the embodiment, active water fracturing fluid is adopted, medium sand with the mesh of 20/40 (850-425 μm) and coarse sand with the mesh of 16/20 (1180-850 μm) are used as supporting mediums, and the displacement of the fracturing fluid is 14-16 m 3 Per min, sand adding strength of 14-18m 3 The ratio of the pre-liquid is more than 80 percent;
the active water fracturing fluid comprises the following components in percentage by mass: 1 to 2 percent of KCl, 0.5 to 1 percent of cleanup additive, 0.5 to 1 percent of bactericide and the balance of water.
Step 5, completing high-pressure grouting operation on the first crack space body by adopting ground grouting equipment, after the grouting standard is reached, displacing grouting liquid to the bottom of the well by adopting clear water, ensuring no grouting liquid in the continuous oil pipe, and obtaining a first grouting modified crack filling body after the grouting operation is finished;
step 6, lifting the coiled tubing, continuing to pressurize to separate the packer device releasing device from the pressure maintaining packer device, and completing setting of the leak-proof device packer, wherein as shown in fig. 4, the pressure maintaining packer device 7 is finally left in the first branch horizontal well, and grouting slurry cannot return to the branch horizontal well any more due to the action of the built-in check valve 72 of the pressure maintaining packer device 7, so that all grouting slurry enters the stratum, and the effectiveness of grouting is ensured; then, the advanced drilling staged fracturing grouting curtain of the water-bearing layer of the coal seam roof is lifted out by a system, and pressure maintaining and packing of the first fracturing section are completed;
step 7, after the first grouting reconstruction crack filling body is coagulated, drilling down to perform milling operation on the pressure maintaining and packing device 7, and then finishing flushing operation on the branch horizontal well, ensuring no barriers and residues in the branch horizontal well, and finishing staged fracturing reconstruction grouting operation of a first fracturing stage in the first branch horizontal well;
step 8, analogizing in sequence, repeating the steps 3 to 7, and completing the sectional fracturing reconstruction grouting operation of the residual fracturing section of the first branch horizontal well;
and 9, repeating the steps 2 to 8 by analogy, and completing the sectional fracturing reconstruction grouting operation of all the branch horizontal wells.
In this embodiment, a stable crack space body is formed in the roof aquifer of the coal seam by means of the three-component horizontal well in the transformation area (the arrow in the figure represents the water flow direction) as shown in fig. 6, the crack space body is grouted to form a grouting transformation crack filling body capable of being used as a stable water-blocking waterproof wall body, and the existence of the grouting transformation crack filling body changes the groundwater flow direction of the roof aquifer, so that the groundwater flow cannot be shoved to the coal face in a large range; finally, a relatively continuous vertical plane water-blocking wall body is formed, the lateral water supply intensity of the water-bearing layer can be cut off or weakened in the transformation area, a vertical sandstone body water-blocking curtain is formed, the underground coal mining area has a safe water-blocking effect, the water inflow of the coal mining area is reduced, the water of the water-bearing layer is effectively reduced or prevented from entering a mine through a roof fracture zone which develops after coal mining, the water reduction of a mine coal face is realized, the safety production requirement of the mine is guaranteed, and the advanced productivity of the mine is fully released.
The foregoing embodiments are merely examples provided for clarity of illustration and are not intended to be limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications which may be extended therefrom are within the scope of the present application.
Claims (9)
1. The system for the advanced drilling staged fracturing grouting curtain of the water-bearing layer of the coal seam roof comprises a first releasing device (1), a lower centralizer (2), a hydraulic anchor (3), an upper centralizer (4), an oil pipe passing packer (5), an injector (6), a pressure maintaining and isolating device (7) and a pressure guiding falling device (8) which are coaxially connected in sequence from back to front;
the pressure maintaining packer device (7) comprises a pressure maintaining packer device releasing device (71) and a built-in one-way valve (72) which are coaxially communicated from back to front, and a leakage-proof device packer (73) is sleeved outside the built-in one-way valve.
2. The system for advanced drilling staged fracturing grouting curtain for the coal seam roof aquifer of claim 1, wherein a connecting device (9) is further arranged between the hydraulic anchor (3) and the upper centralizer (4).
3. The method for the curtain grouting of the staged fracturing of the advanced drilling of the aquifer of the roof of the coal seam is realized by the system for the curtain grouting of the staged fracturing of the advanced drilling of the aquifer of the roof of the coal seam according to claim 1 or claim 2, and comprises the following steps:
step 1, completing the design of a plurality of branch horizontal wells in a reconstruction area; the design comprises the layout position of each branch horizontal well, all fracturing sections of each branch horizontal well and perforation grouting positions of each fracturing section;
step 2, drilling of the first branch horizontal well is completed;
step 3, using a continuous oil pipe to lower a coal seam roof aquifer advanced drilling staged fracturing grouting curtain to a perforation grouting position of a first fracturing section of a first branch horizontal well by using a system, and completing hydraulic injection operation of the first fracturing section of the first branch horizontal well;
step 4, completing fracturing operation of a first fracturing section of the first branch horizontal well by adopting ground fracturing equipment to form a first crack space body;
step 5, completing high-pressure grouting operation on the first crack space body by adopting ground grouting equipment, and obtaining a first grouting modified crack filling body after the grouting operation is finished;
step 6, lifting the continuous oil pipe, continuously pressurizing to separate the packer from the pressure-maintaining packer, completing setting of the packer by the leak-proof device, leaving the pressure-maintaining packer in the first branch horizontal well, and then lifting out the advanced drilling staged fracturing grouting curtain of the water-bearing layer of the coal seam roof by using the system;
step 7, after the first grouting reconstruction crack filling body is coagulated, drilling down to carry out milling operation on the pressure maintaining packing device, and then completing flushing operation on the branch horizontal well to complete sectional fracturing reconstruction grouting operation of a first fracturing section of the first branch horizontal well;
step 8, analogizing in sequence, repeating the steps 3 to 7, and completing the sectional fracturing reconstruction grouting operation of the residual fracturing section of the first branch horizontal well;
and 9, repeating the steps 2 to 8 by analogy, and completing the sectional fracturing reconstruction grouting operation of all the branch horizontal wells.
4. A method of drilling in advance a staged fracturing grouting curtain for a roof aquifer of a coal seam as claimed in claim 3, wherein the vertical spacing between adjacent ones of the plurality of branch horizontal wells in step 1 is 50 to 80 meters.
5. A method for advanced drilling staged fracturing grouting curtain of a roof aquifer of a coal seam as claimed in claim 3, wherein the horizontal distance of the ith fracturing stage of the adjacent branch horizontal well is 20-40 m, wherein i is not less than 1.
6. A method for advanced drilling staged fracturing grouting curtain for a roof aquifer of a coal seam as claimed in claim 5, wherein the design of adjacent branch horizontal wells meets the following conditions: in the vertical direction, the lowest point of the ith fracturing crack of the upper branch horizontal well is lower than the highest point of the ith fracturing crack of the lower branch horizontal well, and an included angle between a connecting line between the highest point of the ith fracturing crack of the lower branch horizontal well and the lowest point of the ith fracturing crack of the upper branch horizontal well and an extension line of the ith fracturing crack of the lower branch horizontal well is 45-90 degrees.
7. A method for advanced drilling staged fracturing grouting curtain for a roof aquifer of a coal seam as claimed in claim 3, wherein the hydraulic jetting operation for completing the first fracturing section of the first branch horizontal well in step 3 comprises the following sub-steps:
step 3.1, using a continuous oil pipe to lower the system for advanced drilling staged fracturing grouting curtain of the water-bearing layer of the coal seam roof to the perforation grouting position of the first fracturing section of the branch horizontal well, and using an injector to perform injection operation at the perforation grouting position, wherein the injection operation is adoptedThe large-discharge and circumferential perforation mode is adopted, and the jet discharge capacity is 2.0-2.5 m 3 The spraying liquid is clean water;
step 3.2, lifting the continuous oil pipe for 20-25 meters after the injection operation is finished;
step 3.3, pressing the ground, and after the set first pressing pressure is reached, opening the hydraulic anchor and then setting on the well wall; continuously pressing until reaching a set second pressing pressure, and realizing pressure setting after expanding the oil pipe passing packer; after continuing to press until reaching the set third pressing pressure, the leakage-proof device packer is permanently set on the well wall; and continuously pressing until the set fourth pressing pressure is reached, then disengaging the pressure guide stripper, lifting the system for the advanced drilling staged fracturing grouting curtain of the water-bearing layer of the top plate of the coal seam, and completing the hydraulic injection operation of the first fracturing section of the first branch horizontal well.
8. A method for advanced drilling staged fracturing grouting curtain of a roof aquifer of a coal seam as claimed in claim 3, wherein in step 3.3, the first pressure < the second pressure < the third pressure < the fourth pressure.
9. The method for advanced drilling staged fracturing grouting curtain of the water-bearing layer of the coal seam roof as claimed in claim 3, wherein in the fracturing operation in the step 4, an active water fracturing fluid is adopted, 20/40 mesh medium sand and 16/20 mesh coarse sand are used as supporting mediums, and the displacement of the fracturing fluid is 14-16 m 3 Per min, sand adding strength of 14-18m 3 The ratio of the pre-liquid is more than 80 percent;
the active water fracturing fluid comprises the following components in percentage by mass: 1 to 2 percent of KCl, 0.5 to 1 percent of cleanup additive, 0.5 to 1 percent of bactericide and the balance of water.
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| CN202311381275.XA CN117386447A (en) | 2023-10-24 | 2023-10-24 | Staged fracturing grouting curtain device and method for advanced drilling of water bearing layer on top plate of coal bed |
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| CN202311381275.XA CN117386447A (en) | 2023-10-24 | 2023-10-24 | Staged fracturing grouting curtain device and method for advanced drilling of water bearing layer on top plate of coal bed |
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