CN107313716B - Drilling method for coal-bed gas well crossing goaf by composite plugging broken rock at hole bottom - Google Patents
Drilling method for coal-bed gas well crossing goaf by composite plugging broken rock at hole bottom Download PDFInfo
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- 238000005553 drilling Methods 0.000 title claims abstract description 118
- 239000011435 rock Substances 0.000 title claims abstract description 68
- 238000000034 method Methods 0.000 title claims abstract description 38
- 239000002131 composite material Substances 0.000 title claims abstract description 18
- 238000004519 manufacturing process Methods 0.000 claims abstract description 30
- 239000003245 coal Substances 0.000 claims abstract description 20
- 239000007788 liquid Substances 0.000 claims abstract description 15
- 239000006260 foam Substances 0.000 claims abstract description 10
- 238000010276 construction Methods 0.000 claims description 24
- 238000007789 sealing Methods 0.000 claims description 20
- 239000011257 shell material Substances 0.000 claims description 20
- 239000004568 cement Substances 0.000 claims description 19
- 239000002002 slurry Substances 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 229910000831 Steel Inorganic materials 0.000 claims description 6
- 230000000149 penetrating effect Effects 0.000 claims description 6
- 238000007711 solidification Methods 0.000 claims description 6
- 230000008023 solidification Effects 0.000 claims description 6
- 239000010959 steel Substances 0.000 claims description 6
- 230000000903 blocking effect Effects 0.000 claims description 4
- 239000002689 soil Substances 0.000 claims description 4
- 239000004035 construction material Substances 0.000 claims description 3
- 238000005516 engineering process Methods 0.000 abstract description 8
- 230000006641 stabilisation Effects 0.000 abstract 1
- 238000011105 stabilization Methods 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 16
- 239000011440 grout Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 238000005065 mining Methods 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 description 1
- 239000003830 anthracite Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 239000004088 foaming agent Substances 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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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
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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
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
- E21B21/14—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor using liquids and gases, e.g. foams
-
- 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
-
- 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
- E21B33/14—Methods or devices for cementing, for plugging holes, crevices or the like for cementing casings into boreholes
-
- 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
- E21B7/20—Driving or forcing casings or pipes into boreholes, e.g. sinking; Simultaneously drilling and casing boreholes
- E21B7/208—Driving or forcing casings or pipes into boreholes, e.g. sinking; Simultaneously drilling and casing boreholes using down-hole drives
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- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Mechanical Engineering (AREA)
- Earth Drilling (AREA)
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
Abstract
The invention belongs to the technical field of coal bed gas resource exploitation, and provides a drilling method for a coal bed gas well through a goaf by using a hole bottom composite plugging broken rock mass, which aims at solving the problems that drilling is difficult and potential safety hazards exist during drilling when a coal bed gas well is constructed through the goaf; the surrounding rock breaking rock mass of the drilling hole is constructed in three stages, wherein auxiliary measures of injecting foam liquid into the hole bottom are implemented in the middle breaking rock mass section, auxiliary measures of grouting the hole bottom are implemented in the remarkable breaking rock mass section, and casing drilling measures are implemented in the caving zone cavity section. The broken rock mass section and the caving zone cavity are safely and efficiently penetrated; meanwhile, the comprehensive stabilization technology of the surface casing, the technical casing and the production casing is utilized, so that the overall rigidity and stability of the well drilling are greatly enhanced.
Description
Technical Field
The invention belongs to the technical field of coal bed gas resource exploitation, and particularly relates to a drilling method for a coal bed gas well of a hole bottom composite plugging broken rock body to pass through a goaf.
Background
The drilling method mainly comprises mud circulation drilling and pneumatic down-the-hole hammer drilling, wherein a surface sleeve is used at the shallow part of the drilling, and a broken rock section can be protected by a technical sleeve to prevent hole collapse. The casing and borehole wall gap is filled with cement slurry.
The main problems existing in the prior art are that the mountain and western jin city anthracite mining industry group limited responsibility company coal and coalbed methane co-mining national key laboratory technicians combine with the construction site analysis: (1) For mud circulation drilling, mud leakage occurs when the mud passes through a fracture zone or a caving zone of a goaf, and the mud cannot be drilled; (2) For pneumatic down-the-hole hammer drilling, high-pressure gas leakage can occur when a fracture zone or a caving zone passing through a goaf, and the problems that no return air or a large amount of gas flows out of a wellhead, so that safe drilling cannot be continued to a designed depth and the like exist; (3) In broken sections of rock mass, the phenomenon of drill sticking and clamping exists, and the phenomenon of drill falling occurs in the cavity area of the caving zone, so that the problem of production safety can be caused.
Disclosure of Invention
Aiming at the problems that drilling is difficult and potential safety hazards exist during drilling when a coal-bed gas well is constructed through a goaf, the invention further provides a drilling method for the coal-bed gas well through the goaf by using a hole bottom to block broken rock bodies in a composite manner.
The invention adopts the following technical scheme:
a drilling method for a coal-bed gas well of a hole bottom composite plugging broken rock body to pass through a goaf adopts a triple sleeve structure and a three-opening drilling construction process, wherein the well body of the coal-bed gas well consists of a first-opening drilling hole, a surface sleeve, a second-opening drilling hole, a technical sleeve, a third-opening drilling hole and a production sleeve, the goaf is penetrated in the two-opening drilling stage, and the broken rock body of surrounding rock of the coal-bed gas well is drilled in the two-opening drilling construction process; the drilling surrounding rock breaking rock mass is sequentially divided into three stages for construction, wherein the first stage is to implement auxiliary measures of injecting foam liquid into the hole bottom of a medium breaking rock mass section, the second stage is to implement auxiliary measures of grouting into the hole bottom of a remarkable breaking rock mass section, and the third stage is to implement casing drilling measures for a caving zone cavity section.
And the top end orifices of the surface sleeve, the technical sleeve and the production sleeve are connected and coupled to form a stable pipe well structure system.
The specific drilling construction process comprises the following steps:
1) Positioning an orifice of a coal-bed gas well and preparing construction materials;
2) Drilling construction, namely penetrating through the fourth system to about 5m below the bedrock surface, and finishing drilling;
3) The surface sleeve is put in, a gap between a drill hole and the surface sleeve is formed, and an outer layer sleeve shell material is injected for waiting for solidification;
4) After the shell materials of the outer layer are initially set, performing secondary drilling construction by adopting a pneumatic down-the-hole hammer, penetrating through weak broken rock bodies, entering medium broken rock bodies, injecting foam liquid, reducing the air leakage of the broken rock bodies and reducing the leakage of high-pressure air;
5) Continuously drilling until the rock mass is obviously broken, if a large amount of air leakage and blocking occur, providing a pneumatic down-the-hole hammer, grouting at the bottom of a hole by using a segmented high-pressure grouting device to form a grouting body with the diameter being 2 times that of the drilled hole, and drilling by using the pneumatic down-the-hole hammer; repeating the step 5) until drilling is carried out until the caving zone is formed;
6) The technical sleeve is put into, a pneumatic down-the-hole hammer drills with the sleeve, directly penetrates through the caving zone cavity, and is lifted when drilling to the extremely broken rock area at the lower part of the caving zone cavity, and the segmented high-pressure grouting device is put into the sleeve again for grouting at the bottom of the hole for waiting for solidification;
7) After the primary setting of the grouting body at the bottom of the hole, drilling the grouting body into a coal seam bottom plate by adopting a pneumatic down-the-hole hammer and a pipe to about 20m, and finishing drilling the hole;
8) Grouting at the bottom of the second drilled hole under high pressure to enable cement paste to return to the caving zone cavity; injecting an inner layer sleeve shell material between the technical sleeve and the surface sleeve, and waiting for solidification to ensure that the top end and the bottom end of the technical sleeve are stable;
9) Drilling construction of three drill holes, namely drilling to a bottom plate of the lower coal seam, and finishing the three drill holes;
10 A production sleeve is put in, cement slurry is injected into the bottom of the three drilled holes at high pressure, and the slurry returns to the hole opening along the gap between the production sleeve and the technical sleeve;
11 Locking the surface sleeve, the technical sleeve and the production sleeve at the orifice part by using locking steel fasteners, thus completing the drilling construction.
The outer layer shell material and the inner layer shell material are respectively prepared by mixing cement, soil and water according to the ratio of 1:1.5:1.80.
The grouting at the bottom of the hole is also pure cement slurry with the water cement ratio of 0.5-1.0.
Step 10) when the production casing is lowered, the pipe orifice of the production casing is at least 0.5m higher than the ground surface.
The method comprises the steps that a sectional high-pressure grouting device is adopted during hole bottom grouting, the sectional high-pressure grouting device comprises a pipe body, the pipe body is of a three-section integrated structure, the middle part of the pipe body is provided with a flower pipe with a plurality of grouting grooves, the upper part and the lower part of the pipe body are respectively provided with screw threads, the screw threads at the upper part and the lower part are respectively provided with a grouting plug combination, a section between the upper grouting plug combination and the lower grouting plug combination is a grouting section, and the upper grouting plug combination can move up and down along the screw threads at the upper part of the grouting device; the top of the screw thread at the upper part of the grouting device is provided with a locking joint for being matched and connected with a drill rod and a grouting pipe.
The slurry stop plug combination comprises a clamping bolt, a rubber sealing ring and an elastic soft rubber ring, wherein the clamping bolt is connected with a screw thread in a matched manner, and the rubber sealing ring and the elastic soft rubber ring are parallel to each other and are coaxially and closely sleeved between the clamping bolt and the sleeve to form a double-layer sealing slurry stop structure. The rubber sealing ring is arranged on the outer side of the elastic soft rubber ring. Namely, for the upper grout stop combination, the elastic soft rubber ring is arranged below the rubber sealing ring, and for the lower grout stop combination, the elastic soft rubber ring is arranged above the rubber sealing ring, so that the inner side is described relative to grouting liquid, the elastic soft rubber ring forms a first layer of seal which is in direct contact with the grouting liquid, and the rubber sealing ring forms a second layer of seal.
The length of the grouting section is 0.5-1m.
The grouting grooves are rectangular notches parallel to the axis direction of the pipe body, at least three layers of the grouting grooves are arranged along the axis direction of the pipe body, each layer of grouting grooves is at least 3 notches, and the notches of the adjacent layers of grouting grooves are arranged in a staggered mode. Ensuring uniform slurry outlet in the grouting section.
The invention mainly solves the following technical problems:
(1) And (3) a drilling technology for safely and efficiently penetrating through the broken rock mass section. The combined drilling measure that a pneumatic down-the-hole hammer is combined with the hole bottom to inject foam liquid is adopted in the medium broken rock mass section (middle upper part of a fracture zone); a combined drilling measure of pneumatic down-the-hole hammer combined with hole bottom grouting is adopted in a section (lower part of a fracture zone) of the remarkable broken rock mass.
(2) And the drilling technology for safely and efficiently penetrating through the caving zone. The method is a measure of adopting a pneumatic down-the-hole hammer to combine with pipe drilling at the caving zone cavity, and adopting proper grouting at the bottom of the caving zone cavity to strengthen broken rock mass so as to root the technical casing.
(3) The comprehensive stabilizing technology of the surface layer sleeve, the technical sleeve and the production sleeve. Filling the outer shell material in the surface sleeve and a drilling gap; the gap between the technical sleeve at the upper part of the orifice and the surface sleeve is filled with an inner sleeve shell material, and the gap between the technical sleeve at the bottom of the two-hole drilling and the hole wall is filled with cement paste, so that the upper end and the lower end of the technical sleeve are stable; the cement slurry is filled into the hole openings in the production sleeve, the technical sleeve and the three drilling gaps, so that the overall rigidity and stability of drilling are greatly enhanced.
Meanwhile, the following technical problems can be solved by utilizing the sectional high-pressure grouting device:
(a) Grouting between the casing and the well wall in sections in the casing is realized, and the length of the grouting section can be selected;
(b) Setting a double-layer grouting valve to realize high-pressure grouting;
(c) The independent high-pressure grouting pipe is arranged, and the common exploration drill pipe can be connected with a grouting device, so that grouting equipment is simplified.
Therefore, the grouting device is used for grouting and reinforcing the outside of the casing pipe of the coal-bed gas well, high-pressure grouting with variable section length can be realized in a designated drilling inner section or position, surrounding rock of the casing pipe outer well wall in a designated area is reinforced, the casing pipe is closely attached to the well wall, and the stability of the coal-bed gas well is greatly enhanced.
Drawings
FIG. 1 is a sectional view of a stage of drilling;
FIG. 2 is a sectional view of a two-hole drilling stage;
FIG. 3 is a sectional view of a three-hole drilling stage;
fig. 4 is a schematic structural view of a segmented high pressure grouting device.
1. A fourth line; 2. weak broken rock mass (bedrock deflection zone); 3. medium crushed rock mass (upper middle of fracture zone); 4. significant breaking of the rock mass (lower fracture zone); 5. a caving zone cavity; 6. an upper coal seam; 7. a coal seam floor; 8. a lower coal seam; 9. an orifice; 10. a first drill hole; 11. a surface layer sleeve; 12. an outer shell material; 13. a technical sleeve; 14. an inner layer shell material; 15. drilling holes at two times; 16. grouting the bottom of the hole; 17. grouting outside the technical sleeve; 18. three-hole drilling; 19. producing a sleeve; 20. producing a sleeve external grouting body; 21. locking notch steel firmware;
31. a drill rod; 32. grouting pipe; 33. a sleeve; 34. a lock joint; 35. screw threads are arranged at the upper part of the grouting device; 36. clamping bolts; 37. a rubber seal ring; 38. an elastic soft rubber ring; 39. grouting grooves; 40. screw threads at the bottom of the grouting device; 41. a tube body.
Detailed Description
Aiming at unfavorable geological conditions of drilling of a coal-bed gas well with a large number of broken rock bodies or cavities in a goaf, the invention solves the technical problem of difficult drilling of broken rock bodies or cavity sections of the goaf by combining auxiliary technologies such as foam liquid injection at the bottom of a hole, hole bottom grouting at the position of a key broken rock body, sleeve follow-up and stable grouting at the end part of a technical sleeve and the like. The technical key point is that the coal-bed gas well is constructed by three perforated diameter drilling holes in sequence in stages, and the goaf is penetrated in two drilling holes. Wherein, the auxiliary measure of injecting foam liquid into the hole bottom is implemented in the middle broken rock mass section (middle upper part of the fracture zone); performing hole bottom grouting auxiliary measures on a section (lower part of a fracture zone) of the remarkable broken rock mass; implementing a casing drilling measure at the caving zone cavity; grouting the top end and the bottom end of the technical sleeve to stabilize the pipe body, and finally welding the surface sleeve, the technical sleeve and the production sleeve into a whole at the orifice to finish drilling construction.
The construction process mainly relates to the following key technologies:
(1) A sectional composite plugging technology for surrounding rock breaking of coal-bed gas well. Comprising the following steps: in the first stage, in a medium broken rock mass (middle upper part of a fracture zone) 3, foam liquid (the concentration of a foaming agent and the pump quantity are adjusted according to working conditions) is injected into the bottom of a hole, so that the air leakage of the broken rock mass is reduced, and the drilling efficiency is improved. In the second stage, the remarkable broken rock mass (lower part of a fracture zone) 4 is subjected to grouting at the bottom of a hole by adopting a segmented high-pressure grouting device to form a grouting body 16 with the diameter being 2 times that of a drilled hole, the grouting body is pure cement slurry (the cement ratio is 0.5-1.0, the accelerator water glass is 3 percent, and 1 percent of glass fiber is added if necessary), so that the seriously broken rock mass is effectively plugged and reinforced, accidents such as drilling sticking of a pneumatic down-the-hole hammer and air leakage of high-pressure air are avoided, and the construction safety is improved.
(2) The triple sleeve structure well drilling construction of the coal bed gas well and the connection coupling technology thereof. Comprising the following steps: the surface sleeve 11 penetrates through the stratum of the fourth system 1 and is embedded and fixed on the underlying bedrock by about 5m; the technical sleeve penetrates through the deflection zone 2, the upper part 3 and the lower part 4 in the fracture zone, the caving zone and the cavity 5 of the fracture zone from the orifice 9, and is combined with the following pipe drilling to reach about 20m in the coal bed bottom plate 7; after the three-hole drilling 18 is finished, the production sleeve 19 is installed in full hole depth, and the pipe orifice of the production sleeve is 0.5m higher than the orifice; and the triple sleeves are connected and coupled with each other to form a tube well structure with higher rigidity. Wherein, the outer surface sleeve 11 is filled with an outer sleeve shell material 12 (the proportion: cement: soil: water=1:1.5:1.80), the surface sleeve 11 and the technical sleeve 13 are bonded by an inner sleeve shell material 14 (the proportion: cement: soil: water=1:1.5:1.80), and the bottom of the technical sleeve 13 is bonded on the wall of the two-open drill hole 15 by a technical sleeve outer grouting body 17; the production casing 19 and the technical casing 13 are bonded by the production casing external grouting body 20; the surface sleeve 11, the technical sleeve 13 and the production sleeve 19 are welded by adopting a locking steel fastener 21 at the orifice to form a stable pipe well structure system.
The specific drilling construction process comprises the following steps:
1) Positioning a coal bed gas well orifice 9 and preparing construction materials;
2) Constructing a first drilling hole 10, penetrating through the fourth system 1 to about 5m below the bedrock surface, and finishing the first drilling hole;
3) The surface sleeve 11 is put in, an open drill hole 10 is arranged at a gap with the surface sleeve 11, an outer shell material 12 is injected, and the surface sleeve is waiting for solidification;
4) After the outer shell material 12 is initially set, a pneumatic down-the-hole hammer is adopted to carry out two-hole drilling 15 construction, the two-hole drilling passes through a weak broken rock mass (bedrock deflection zone) 2, enters a medium broken rock mass (middle upper part of a fracture zone) 3, and foam liquid is injected, so that the air leakage of the broken rock mass is reduced, and the high-pressure gas leakage is reduced;
5) And continuing drilling until the rock mass (lower part of a fracture zone) 4 is obviously broken, if a great amount of phenomena such as air leakage and blocking occur, providing a pneumatic down-the-hole hammer, grouting at the bottom of a hole by using a segmented high-pressure grouting device to form a grouting body 16 with the diameter being 2 times that of the drilled hole, and drilling by using the pneumatic down-the-hole hammer. Repeating the step 5) until drilling to the caving hole 5.
6) And (3) a technical sleeve 13 is put into, a pneumatic down-the-hole hammer drills with the sleeve, directly penetrates through the caving zone cavity 5, drills up when drilling to a very broken rock area at the lower part of the caving zone, and is put into a segmented high-pressure grouting device again to perform grouting at the bottom of the hole, and waiting for solidification.
7) And after the primary setting of the grouting body 16 at the bottom of the hole, drilling the hole into the coal seam floor 7 by using a pneumatic down-the-hole hammer and a pipe to about 20m, and finishing the secondary drilling 15.
8) Grouting at the bottom of the second drilling hole 15 under high pressure to enable cement slurry to return to the caving zone cavity 5; an inner layer casing material 14 is injected between the technical casing 13 and the surface casing 11 for curing, so that the top end and the bottom end of the technical casing are stable.
9) And (3) drilling the three-way drilling hole 18, drilling to the bottom plate of the lower coal seam 8, and finishing the three-way drilling hole 18.
10 A production casing 19 is run in, the pipe orifice is 0.5m above the ground surface, and cement slurry is injected at high pressure at the bottom of the three-hole drill hole 18, so that the slurry returns to the hole orifice along the gap between the production casing 19 and the technical casing 13.
11 At the position of the orifice 9, the surface casing 11, the technical casing 13 and the production casing 19 are locked by using a locking steel fastener 21, thus completing the drilling construction.
The construction process mainly involves the following key part connection:
(1) The surface sleeve 11 and the hole wall gap of an open drill hole 10 are bonded by the shell material 12;
(2) The top end part of the pipe orifice of the technical sleeve 13 is bonded on the surface sleeve 11 through an inner layer sleeve shell material 14, and the bottom of the sleeve is bonded on the wall of the two open holes 15 through a technical sleeve outer grouting body 17;
(3) The production casing 19 and the technical casing 13 are bonded by the production casing external grouting body 20;
(4) The orifices of the surface sleeve 11, the technical sleeve 13 and the production sleeve 19 are welded together by locking notch steel fasteners 21.
When grouting, a sectional high-pressure grouting device shown in fig. 4 is adopted, the pipe body of the sectional high-pressure grouting device is divided into an upper part, a middle part and a lower part, the upper part of the grouting device is provided with screw threads with the length of 0.1-0.5m, the middle part of the grouting device is provided with a flower pipe part with 3 pairs of grouting grooves, the length of the grouting device is about 0.5m, and the lower part of the grouting device is provided with screw threads with the length of 0.2 m. And the grouting stopper combination (comprising three clamping bolts, a rubber sealing ring and an elastic soft rubber ring) is arranged at the screw thread at the upper part of the grouting device and the screw thread at the bottom of the grouting device. The upper grouting stop combination can move along the screw thread at the upper part of the grouting device, so that grouting between the sleeve and the well wall is realized in sections in the sleeve, the length of a grouting section can be selected, and the length range is generally selected to be 0.5-1.0m. The rubber sealing ring and the elastic soft rubber ring are arranged in the grouting plug combination, the grouting plug combination has the double-layer grouting effect, the elastic soft rubber ring is pressed and closely attached to the sleeve under the grouting pressure effect, the grouting performance is remarkably improved, and high-pressure grouting is realized.
The special lock joint can be connected with the drill rod, the grouting pipe and the screw thread at the upper part of the grouting device, the drill rod can select a common exploration drill rod, the grouting pipe adopts a high-pressure grouting pipe, the flexibility of equipment material selection is improved, and the cost is reduced.
The use flow of the sectional high-pressure grouting device is as follows:
(1) And selecting a grouting device pipe body with a proper diameter, and preparing corresponding accessories including a drill rod, a grouting pipe, a lock joint, a clamping bolt, a rubber sealing ring, an elastic soft rubber ring and the like.
(2) The lower grout stop plug combination (comprising three clamping bolts, a rubber sealing ring and an elastic soft rubber ring) is screwed on the screw buckle at the bottom of the grouting device in sequence.
(3) The upper grouting stop combination (comprising three clamping bolts, a rubber sealing ring and an elastic soft rubber ring) is screwed on the screw thread on the upper part of the grouting device in sequence, and the length of the grouting section is adjusted according to the requirement, so that the grouting stop combination is stopped at a certain fixed position.
(4) And (3) connecting the first section of drill rod and the corresponding grouting pipe with the locking joint in a threaded manner, and hoisting the grouting device into the sleeve.
(5) According to the method, the drill rod and the grouting pipe are sequentially connected to reach the part needing grouting in the sleeve.
(6) And injecting clean water from the grouting pipe at high pressure at the pipe orifice of the ground, enabling the high-pressure water to enter the grouting device, extruding the elastic soft rubber ring to be closely adhered to the pipe wall, and grouting Kong Pokai on the sleeve.
(7) And (3) preparing grouting liquid at a ground wellhead, injecting the grouting liquid from a grouting pipe at high pressure, and pressing the grouting liquid into a gap between a sleeve and a well wall from a sleeve grouting hole, so that sectional grouting reinforcement is realized.
(8) The grouting device can be lifted to the pipe orifice in time to reach the grouting requirement, and the grouting device is flushed.
The connection points and the relation of the sectional high-pressure grouting device are as follows:
the drill rod is connected with the grouting pipe through a lock joint, and the lock joint is connected with the upper grouting device through threads. The grouting stopper combination at the upper part of the grouting device comprises clamping bolts (3), a rubber sealing ring and an elastic soft rubber ring, wherein the grouting stopper combination is provided with an inner ring, inner sleeve threads in the inner ring sequentially pass through one end of the upper part of the grouting device and are screwed to a fixed position along the threads at the upper part of the grouting device. The rubber sealing ring and the elastic soft rubber ring are clamped by the clamping bolts. The grouting stopper assembly at the lower part of the grouting device comprises clamping bolts (3), a rubber sealing ring and an elastic soft rubber ring, wherein the grouting stopper assembly is provided with an inner ring, inner sleeve threads in the inner ring sequentially pass through screw threads at the bottom of the grouting device and are screwed to a fixed position. The rubber sealing ring and the elastic soft rubber ring are clamped by three clamping bolts. The upper and lower slurry stop plug combination is closely attached to the sleeve.
Claims (10)
1. A drilling method for a coal-bed gas well of a hole bottom composite plugging broken rock body to pass through a goaf adopts a triple sleeve structure and a three-opening drilling construction process, wherein the well body of the coal-bed gas well consists of a first-opening drilling hole (10) and a surface sleeve (11), a second-opening drilling hole (15) and a technical sleeve (13), a third-opening drilling hole (18) and a production sleeve (19), and the goaf is passed through at the two-opening drilling stage, and the drilling method is characterized in that: when the secondary drilling construction is carried out through the goaf, sectional composite blocking is carried out on the broken rock mass of the surrounding rock of the coal bed gas well; the drilling surrounding rock breaking rock mass is sequentially divided into three stages for construction, wherein the first stage is to implement auxiliary measures of injecting foam liquid into the hole bottom in the section of the medium breaking rock mass (3), the second stage is to implement auxiliary measures of grouting into the hole bottom in the section of the remarkable breaking rock mass (4), and the third stage is to implement casing drilling measures in the section of the caving zone (5).
2. The method for drilling the coal-bed gas well through the goaf by using the hole bottom composite plugging broken rock mass according to claim 1, wherein the method comprises the following steps: the top end orifices of the surface casing (11), the technical casing (13) and the production casing (19) are connected and coupled to form a stable pipe well structure system.
3. The drilling method for the coal-bed gas well of the hole bottom composite plugging broken rock body to pass through the goaf according to claim 2, which is characterized in that the specific drilling construction process comprises the following steps:
1) Positioning a coal bed gas well orifice (9), and preparing construction materials;
2) Constructing a first drilling hole (10), penetrating through the fourth system (1) to be below the bedrock surface, and finishing the first drilling hole;
3) The surface sleeve (11) is put in, and an outer layer sleeve shell material (12) is injected into a gap between the drill hole (10) and the surface sleeve (11) for waiting to solidify;
4) After the outer shell material (12) is initially set, a pneumatic down-the-hole hammer is adopted to perform two-hole drilling (15) construction, the two-hole drilling penetrates through the weak broken rock mass (2), enters the medium broken rock mass (3), and is injected with foam liquid, so that the air leakage of the broken rock mass is reduced, and the leakage of high-pressure air is reduced;
5) Continuously drilling until the rock mass (4) is obviously broken, if a large amount of air leakage and blocking occur, providing a pneumatic down-the-hole hammer, grouting at the bottom of a hole by using a segmented high-pressure grouting device to form a grouting body (16) with the diameter being 2 times that of the drilled hole, and drilling by using the pneumatic down-the-hole hammer; repeating the step 5) until drilling to the caving zone cavity (5);
6) A technical sleeve (13) is put into, a pneumatic down-the-hole hammer drills with the sleeve, directly penetrates through the caving zone cavity (5), drills up when drilling to a very broken rock area at the lower part of the caving zone cavity (5), and is put into a segmented high-pressure grouting device again to perform grouting at the bottom of the hole, and waiting for solidification;
7) After the primary setting of the hole bottom grouting body (16), drilling into the coal seam bottom plate (7) by adopting a pneumatic down-the-hole hammer and a pipe, and finishing the two-hole drilling (15);
8) Grouting the bottom of the two holes (15) under high pressure to enable cement paste to return to the caving zone cavity (5); injecting an inner layer sleeve shell material (14) between the technical sleeve (13) and the surface sleeve (11) for curing, so that the top end and the bottom end of the technical sleeve (13) are stable;
9) Drilling construction of a three-way drilling hole (18), wherein the three-way drilling hole (18) is drilled to the bottom plate of the lower coal seam (8);
10 A production casing (19) is put in, cement slurry is injected into the bottom of a three-hole drill (18) at high pressure, and the slurry is returned to the orifice along the gap between the production casing (19) and the technical casing (13);
11 The surface sleeve (11), the technical sleeve (13) and the production sleeve (19) are locked at the orifice (9) by using a locking steel fastener (21), so that the drilling construction is completed.
4. The method for drilling a coal-bed gas well through a goaf by using the hole bottom composite plugging broken rock mass according to claim 3, wherein the method comprises the following steps: the outer shell material (12) and the inner shell material (14) are respectively prepared by mixing cement, soil and water according to the ratio of 1:1.5:1.80.
5. The method for drilling the coal-bed gas well through the goaf by using the hole bottom composite plugging broken rock mass according to claim 4, wherein the method comprises the following steps: the grouting at the bottom of the hole is also pure cement slurry with the water cement ratio of 0.5-1.0.
6. The method for drilling the coal-bed gas well through the goaf by using the hole bottom composite plugging broken rock mass according to claim 5, wherein the method comprises the following steps: step 10) when the production casing (19) is lowered, the pipe orifice of the production casing (19) is at least 0.5m higher than the surface of the earth.
7. The method for drilling the coal-bed gas well through the goaf by using the hole bottom composite plugging broken rock mass according to claim 6, wherein the method comprises the following steps: the method comprises the steps that a sectional high-pressure grouting device is adopted during hole bottom grouting, the sectional high-pressure grouting device comprises a pipe body (41), the pipe body (41) is of a three-section integrated structure, the middle part of the pipe body (41) is a flower pipe provided with a plurality of grouting grooves (39), the upper part and the lower part of the pipe body (41) are respectively provided with screw threads, a grouting plug combination is respectively arranged at the upper screw threads and the lower screw threads, a grouting section is arranged at a section between the upper grouting plug combination and the lower grouting plug combination, and the upper grouting plug combination can move up and down along the screw threads at the upper part of the grouting device; the top end of the screw thread at the upper part of the grouting device is provided with a locking joint (34) which is used for being matched and connected with a drill rod (31) and a grouting pipe (32).
8. The method for drilling the coal-bed gas well through the goaf by using the hole bottom composite plugging broken rock mass according to claim 7, wherein the method comprises the following steps: the slurry stop plug assembly comprises a clamping bolt (36), a rubber sealing ring (37) and an elastic soft rubber ring (38), wherein the clamping bolt (36) is connected with a screw thread in a matched manner, and the rubber sealing ring (37) and the elastic soft rubber ring (38) are mutually parallel and coaxially tightly sleeved between the clamping bolt (36) and the sleeve (33) to form a double-layer sealing slurry stop structure; in the axial direction, the rubber sealing ring (37) is farther from the grouting section than the elastic soft rubber ring (38).
9. The method for drilling the coal-bed gas well through the goaf by using the hole bottom composite plugging broken rock mass according to claim 8, wherein the method comprises the following steps: the length of the grouting section is 0.5-1m.
10. The method for drilling the coal-bed gas well through the goaf by using the hole bottom composite plugging broken rock mass according to claim 9, wherein the method comprises the following steps: the grouting grooves (39) are rectangular notches parallel to the axis direction of the pipe body (41), at least three layers of notches are arranged along the axis direction of the pipe body (41), each layer of notches is at least 3, and notches of adjacent layers of notches are arranged in a staggered mode.
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| CN109519149A (en) * | 2018-09-28 | 2019-03-26 | 山西晋城无烟煤矿业集团有限责任公司 | A kind of coal bed gas passes through the full well cementing method of goaf well |
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| CN109989752B (en) * | 2019-05-13 | 2023-12-19 | 西安科技大学 | Internal injection type static broken coal bed surrounding rock pressure relief device |
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| CN112855021A (en) * | 2021-01-20 | 2021-05-28 | 中煤科工集团西安研究院有限公司 | Coal mine goaf stratum reconstruction and horizontal well drilling completion method |
| CN112901247A (en) * | 2021-04-06 | 2021-06-04 | 中国矿业大学 | Coal mine underground multistage sleeve long-distance fire prevention and extinguishing drilling construction method |
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