LU500251B1 - Method for fixed-point collapse protection of upward gas extraction borehole - Google Patents
Method for fixed-point collapse protection of upward gas extraction borehole Download PDFInfo
- Publication number
- LU500251B1 LU500251B1 LU500251A LU500251A LU500251B1 LU 500251 B1 LU500251 B1 LU 500251B1 LU 500251 A LU500251 A LU 500251A LU 500251 A LU500251 A LU 500251A LU 500251 B1 LU500251 B1 LU 500251B1
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- Prior art keywords
- gas extraction
- cylindrical
- coal
- borehole
- upward gas
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- 238000000605 extraction Methods 0.000 title claims abstract description 70
- 238000000034 method Methods 0.000 title claims abstract description 32
- 239000003245 coal Substances 0.000 claims abstract description 70
- 239000000463 material Substances 0.000 claims abstract description 10
- 238000001514 detection method Methods 0.000 claims abstract description 5
- 230000005484 gravity Effects 0.000 claims abstract description 5
- 238000011065 in-situ storage Methods 0.000 claims abstract description 5
- 238000003780 insertion Methods 0.000 claims description 16
- 230000037431 insertion Effects 0.000 claims description 16
- 238000009826 distribution Methods 0.000 claims description 4
- 229910000278 bentonite Inorganic materials 0.000 claims description 3
- 239000000440 bentonite Substances 0.000 claims description 3
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 3
- 238000005065 mining Methods 0.000 abstract description 4
- 230000000694 effects Effects 0.000 abstract description 2
- 230000002265 prevention Effects 0.000 abstract description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 238000010586 diagram Methods 0.000 description 2
- 239000002817 coal dust Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000000887 hydrating effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
Classifications
-
- 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
- E21F7/00—Methods or devices for drawing- off gases with or without subsequent use of the gas for any purpose
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- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
Disclosed is a method for fixed-point collapse protection of an upward gas extraction borehole, wherein the method comprises the following steps: performing in situ detection on a fracture of the upward gas extraction borehole with a borehole detector to determine each easily-collapsed position in the upward gas extraction borehole and a length thereof; and pushing prefabricated cylindrical coal into the gas extraction borehole, thus, extracting a pushing rod from the upward gas extraction borehole when the cylindrical coal is pushed to the easily-collapsed position that needs protection, wherein at the moment, under the effect of its gravity, the cylindrical coal itself can be fixed to the easily-collapsed position of the upward gas extraction borehole by means of compressing and clamping action of two extending barb structures, and the smoothness of a gas extraction channel can be guaranteed by through holes at the center, such that fixed-point and fixed-length collapse prevention of the gas extraction borehole is achieved. In addition, the barb structures are made from a PVC material, which does not affect subsequent coal mining. As the cylindrical coal is similar to a coal body in component, the quality of mined coal is not affected, such that the quality of mined coal is ensured.
Description
BL-5247 vs S00275 1 METHOD FOR FIXED-POINT COLLAPSE PROTECTION OF UPWARD
TECHNICAL FIELD The present invention relates to a method for preventing collapse of a gas extraction borehole, in particular to a method for fixed-point collapse protection of an upward gas extraction borehole.
BACKGROUND With advantages of easy construction, low cost and the like, gas extraction by downhole drilling has been widely applied in gas control of coal mines in China. However, affected by factors such as crustal stress and a gas pressure, a problem of collapse of a borehole in a gas extraction process of a soft seam is severe. Collapse of the borehole blocks a channel through which gas flows outward, which will affect efficient extraction of gas and downhole gas control remarkably to affect safe production of a mine. The soft seam accounts for a huge proportion in workable seams in China, and collapse of the borehole of the soft seam is a major problem of restricting efficient extraction of downhole gas. At present, a sieve tube is primarily sent to the borehole to prevent collapse of the borehole. However, as coal dust is reserved in the formed borehole to different extents and the borehole of the soft seam collapses locally within a short time, efficient extraction of borehole gas is affected as the sieve tube cannot penetrate through a region of the collapse of the borehole usually in actual use.
A patent with the application publication number of CN109736875A provides a device and method for preventing collapse of a borehole of a seam. The method includes injecting porous concrete into an easily-collapsed section of the borehole to support the borehole actively. The porous concrete has the characteristics of high strength, high porosity and the like, and not only can support the easily-collapsed section of the borehole effectively, but also has a very good spatial pore characteristic, thereby, it is guaranteed that gas passes through freely. Although the method solves the 1
BL-5247 problem of preventing collapse of the borehole at different depths to a certain extent, ad there are still problems in a using process: (1) the method includes injecting a concrete material into the borehole at a fixed point, wherein the concrete material contains a lot of water, a soft coal body at an upper boundary of the easily-collapsed section is argillized when encountering with water and falls into the borehole to cover an upper side of the porous concrete material to plug a flowing channel of gas on the porous concrete so as to affect the smoothness of the gas flowing channel in the borehole; (2) water needed to be added to mix the porous concrete according to a formula is fixed, and as the borehole is dried, a lot of water in the mixed porous concrete is absorbed by the soft coal body in the collapsed section to lead to reduction of water for hydrating and hardening the porous concrete to further affect strength and performance of the porous concrete after solidification; and (3) the injected concrete material will be reserved in the gas extraction borehole continuously and the part of the concrete material will be mixed into mined coal to affect the quality of the mined coal when the part of coal body is mined in a later period.
SUMMARY Aiming at the problem in the prior art, the present invention provides a method for fixed-point collapse protection of an upward gas extraction borehole. The method not only can protect collapse of the upward gas extraction borehole effectively to guarantee smoothness of the gas extraction channel, but also does not affect the subsequent coal body mining and the quality of the mined coal as well.
In order to achieve the purpose, the technical scheme adopted by present invention is as follows: a method for fixed-point collapse protection of an upward gas extraction borehole, includes specific steps: A. performing in situ detection on a fracture of the upward gas extraction borehole with a borehole detector to determine each easily-collapsed position in the upward gas 2
BL-5247 extraction borehole and a length thereof by combining a fracture distribution and ad development condition in the borehole;
B. preparing a plurality of cylindrical coals, wherein through holes are formed in the centers of the cylindrical coals and axes of the through holes and axes of the cylindrical coals are coaxial, two mounting holes are symmetrically formed on the middle of a side wall of each of the cylindrical coals, a barb structure is arranged in each mounting hole and one end of each of the two barb structures extends out of the side wall of each of the cylindrical coals from the two mounting holes respectively, and the other end of each of the two barb structures is connected in the through holes through a elastic sheet, and at the moment, the two barb structures are in an initial unextended state; and arranging a pushing device, wherein the pushing device comprises a push-in rod and a plurality of connecting rods, the push-in rod is comprised of a rod body, an insertion tube and a baffle plate, one end of the insertion tube is coaxially and fixedly connected to one end of the rod body, the baffle plate is fixed to a connection of the rod body and the insertion tube, and the axis of the rod body is perpendicular to the baffle plate;
C. selecting one cylindrical coal, wherein the cylindrical coal is placed on the baffle plate, and the other end of the insertion tube extends into the through hole of the cylindrical coal, such that the cylindrical coal and the push-in rod are fixed relatively, then determining the deepest easily-collapsed position in the upward gas extraction borehole according to the step A, wherein the push-in rod with the cylindrical coal starts to extend into the upward gas extraction borehole, and the two barb structures are limited by an inner wall of the upward gas extraction borehole during the extending process, such that the two barb structures are compressed toward the through holes, and at this moment, the elastic sheet is stressed to deform, and thus, a elastic force of the elastic sheet is increased, and then the other end of the push-in rod is in threaded connection with one connecting rod, the expending of the cylindrical coal into the upward gas extraction borehole is continued, then the connecting rod is in threaded
3
BL-5247 connection to a next connecting rod, and the process is repeated until the cylindrical ad coals are conveyed to the uppermost end of the deepest easily-collapsed position of the upward gas extraction borehole, the plurality of connecting rods and the push-in rods are removed successively from the upward gas extraction borehole, and at the movement, as the cylindrical coal is only subjected to gravity action due to the absence of push-in force, the cylindrical coal has a trend of moving toward the lower side of the upward gas extraction borehole, the two barb structures are subjected to the elastic force action of the elastic sheet, such that the two barb structures extend toward two sides of each of the cylindrical coal, furthermore, the two barb structures are compressed and clamped to the inner wall of the upward gas extraction borehole, and the cylindrical coal is fixed at a current position; D. repeating the step C, then selecting one cylindrical coal to be placed below the previous cylindrical coal, repeating the process until a placement length of the cylindrical coal is larger than the length of the deepest easily-collapsed position, thereby fulfilling fixed-point protection of the easily-collapsed position; and E. selecting the easily-collapsed position closest to the easily-collapsed position in the step D from the easily-collapsed positions determined in the step A, then repeating the steps B and C to fulfill fixed point protection of the easily-collapsed position, and repeating the process like this till fulfilling fixed-point protection of all of the easily- collapsed positions of the upward gas extraction borehole.
Further, the cylindrical coals are prepared by mixing pulverized coal powder and bentonite, a diameter of each of the cylindrical coals is 0.8-0.9 times of a diameter of the borehole, the cylindrical coal has a length of 0.2-0.4 m, and a diameter of each of the through holes is 0.5-0.6 time of the diameter of each of the cylindrical coals.
Further, a diameter of each of the two fully unfolded barb structures is 1.1-1.12 times of the diameter of the borehole, and the barb structure and the elastic sheet are made from PVC materials.
4
BL-5247 Further, the rod body has a length of 1.15-1.7 m, the insertion tube has a length of ad
0.15-0.2 m, and the connecting rod has a length of 1-1.5 m.
By performing in situ detection on a fracture of the upward gas extraction borehole by adopting a borehole detector to determine each easily-collapsed position in the upward gas extraction borehole and a length thereof by combining a fracture distribution and development condition in the borehole, it is favorable to determine the position needing fixed-point protection of the gas extraction borehole. The cylindrical coals internally provided with the through holes are pushed into the gas extraction borehole and are provided with the barb structures, thus, a pushing rod is extracted from the upward gas extraction borehole when the cylindrical coal is pushed to the easily- collapsed position that needed protection, wherein at the moment, under the effect of its gravity, the cylindrical coal itself can be fixed to the easily-collapsed position of the upward gas extraction borehole by means of compressing and clamping action of two extending barb structures, and the smoothness of a gas extraction channel can be guaranteed by through holes at the center, such that fixed-point and fixed-length collapse prevention of the gas extraction borehole is achieved. In addition, the barb structures are made from a PVC material, which does not affect subsequent coal body mining. As the cylindrical coal is similar to a coal body in component, the quality of the mined coal is ensured. Therefore, the method not only can protect collapse of the upward gas extraction borehole effectively to guarantee smoothness of the gas extraction channel, but also does not affect the subsequent coal body mining and the quality of the mined coal as well.
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a section view of the cylindrical coals in the present invention; Fig. 2 is a top view of the Fig. 1; Fig. 3 1s a structural schematic diagram of the push-in rod in the present invention; Fig. 4 is a layout protecting schematic diagram of the present invention.
BL-5247 In the drawings, 1, cylindrical coal, 1-1, through hole, 1-2, barb structure, 2, push- 17000851 in rod, 2-1, insertion tube, 2-2, baffle plate, 2-3, rod body, 3, upward gas extraction bore hole, 4, seam.
DETAILED DESCRIPTION Further description of the present invention will be made below.
As shown in the Fig. 1 to Fig. 4, the method includes the specific steps: A. in situ detection is performed on a fracture of the upward gas extraction borehole with a borehole detector to determine each easily-collapsed position in the upward gas extraction borehole and a length thereof by combining a fracture distribution and development condition in the borehole 3; B. a plurality of cylindrical coals 1 are prepared, wherein through holes 1-1 are formed in the centers of the cylindrical coals 1 and axes of the through holes 1-1 and axes of the cylindrical coals are coaxial; two mounting holes are symmetrically formed on the middle of a side wall of each of the cylindrical coals 1, a barb structure 1-2 1s arranged in each mounting hole and one end of each of the two barb structures 1-2 extends out of the side wall of each of the cylindrical coals 1 from the two mounting holes respectively, and the other end of each of the two barb structures 1-2 1s connected in the through holes through a elastic sheet, and at the moment, the two barb structures 1-2 are in an initial unextended state; and a pushing device is arranged, wherein the pushing device includes a push-in rod 2 and a plurality of connecting rods, the push-in rod is comprised of a rod body 2-3, an insertion tube 2-1 and a baffle plate 2-2, one end of the insertion tube 2-1 is coaxially and fixedly connected to one end of the rod body 2-3, the baffle plate 2-2 is fixed to a connection of the rod body 2-3 and the insertion tube 2-1, and the axis of the rod body 2-3 is perpendicular to the baffle plate 2-2; C, one cylindrical coal is selected, wherein the cylindrical coal 1 is placed on the baftle plate 2-2, and the other end of the insertion tube 2-1 extends into the through hole 1-1 of the cylindrical coal 1, such that the cylindrical coal 1 and the push-in rod 2 are 6
BL-5247 fixed relatively, then the deepest easily-collapsed position is determined in the upward ad gas extraction borehole 3 according to the step A, wherein the push-in rod 2 with the cylindrical coal 1 starts to extend into the upward gas extraction borehole 3, and the two barb structures 1-2 are limited by an inner wall of the upward gas extraction borehole 3 during the extending process, such that the two barb structures 1-2 are compressed toward the through holes 1-1, and at this moment, the elastic sheet is stressed to deform, and thus, an elastic force of the elastic sheet is increased, and then the other end of the push-in rod 2 is in threaded connection with one connecting rod, the expending of the cylindrical coal into the upward gas extraction borehole 3 is continued, then the connecting rod is in threaded connection to a next connecting rod, and the process is repeated until the cylindrical coals 1 are conveyed to the uppermost end of the deepest easily-collapsed position of the upward gas extraction borehole 3, the plurality of connecting rods and the push-in rods 2 are removed successively from the upward gas extraction borehole 3, and at the movement, as the cylindrical coal 1 is only subjected to gravity action due to the absence of push-in force, the cylindrical coal 1 has a trend of moving toward the lower side of the upward gas extraction borehole 3, the two barb structures 1-2 are subjected to the elastic force action of the elastic sheet, such that the two barb structures 1-2 extend toward two sides of each of the cylindrical coal 1, furthermore, the two barb structures 1-2 are compressed and clamped to the inner wall of the upward gas extraction borehole 3, and the cylindrical coal 1 is fixed at a current position;
D. the step C is repeated, then one cylindrical coal 1 is selected to be placed below the previous cylindrical coal, the process is repeated until a placement length of the cylindrical coal 1 is larger than the length of the deepest easily-collapsed position, thereby fulfilling fixed-point protection of the easily-collapsed position; and
E. the easily-collapsed position closest to the easily-collapsed position is selected in the step D from the easily-collapsed positions determined in the step A, then the steps B and C are repeated to fulfill fixed point protection of the easily-collapsed position,
7
BL-5247 and repeating the process like this till fulfilling fixed-point protection of all of the 17000881 easily-collapsed positions of the upward gas extraction borehole.
Further, the cylindrical coals are prepared by mixing pulverized coal powder and bentonite, a diameter of each of the cylindrical coals is 0.8-0.9 times of a diameter of the borehole, the cylindrical coal has a length of 0.2-0.4 m, and a diameter of each of the through holes is 0.5-0.6 times of the diameter of each of the cylindrical coals.
Further, a diameter of each of the two fully unfolded barb structures is 1.1-1.12 times of the diameter of the borehole, and the barb structure and the elastic sheet are made from PVC materials.
Further, the rod body has a length of 1.15-1.7 m, the insertion tube has a length of
0.15-0.2 m, and the connecting rod has a length of 1-1.5 m.
8
Claims (4)
1. A method for fixed-point collapse protection of an upward gas extraction borehole, characterized by comprising the following steps: A. performing in situ detection on a fracture of the upward gas extraction borehole with a borehole detector to determine each easily-collapsed position in the upward gas extraction borehole and a length thereof by combining a fracture distribution and development condition in the borehole; B. preparing a plurality of cylindrical coals, wherein through holes are formed in the centers of the cylindrical coals and axes of the through holes and axes of the cylindrical coals are coaxial; two mounting holes are symmetrically formed on the middle of a side wall of each of the cylindrical coals, a barb structure is arranged in each mounting hole and one end of each of the two barb structures extends out of the side wall of each of the cylindrical coals from the two mounting holes respectively, and the other end of each of the two barb structures is connected in the through holes through a elastic sheet, and at the moment, the two barb structures are in an initial unextended state; and arranging a pushing device, wherein the pushing device comprises a push-in rod and a plurality of connecting rods, the push-in rod is comprised of a rod body, an insertion tube and a baffle plate, one end of the insertion tube is coaxially and fixedly connected to one end of the rod body, the baffle plate is fixed to a connection of the rod body and the insertion tube, and the axis of the rod body is perpendicular to the baffle plate; C. selecting one cylindrical coal, wherein the cylindrical coal is placed on the baffle plate, and the other end of the insertion tube extends into the through hole of the cylindrical coal, such that the cylindrical coal and the push-in rod are fixed relatively, then determining the deepest easily-collapsed position in the upward gas extraction borehole according to the step A, wherein the push-in rod with the cylindrical coal starts to extend into the upward gas extraction borehole, and the two barb structures are limited by an inner wall of the upward gas extraction borehole during the extending 9
BL-5247 process, such that the two barb structures are compressed toward the through holes, and ad at this moment, the elastic sheet is stressed to deform, and thus, a elastic force of the elastic sheet is increased, and then the other end of the push-in rod is in threaded connection with one connecting rod, the expending of the cylindrical coal into the upward gas extraction borehole is continued, then the connecting rod is in threaded connection to a next connecting rod, and the process is repeated until the cylindrical coals are conveyed to the uppermost end of the deepest easily-collapsed position of the upward gas extraction borehole, the plurality of connecting rods and the push-in rods are removed successively from the upward gas extraction borehole, and at the movement, as the cylindrical coal is only subjected to gravity action due to the absence of push-in force, the cylindrical coal has a trend of moving toward the lower side of the upward gas extraction borehole, the two barb structures are subjected to the elastic force action of the elastic sheet, such that the two barb structures extend toward two sides of each of the cylindrical coal, furthermore, the two barb structures are compressed and clamped to the inner wall of the upward gas extraction borehole, and the cylindrical coal is fixed at a current position; D. repeating the step C, then selecting one cylindrical coal to be placed below the previous cylindrical coal, repeating the process until a placement length of the cylindrical coal is larger than the length of the deepest easily-collapsed position, thereby fulfilling fixed-point protection of the easily-collapsed position; and E. selecting the easily-collapsed position closest to the easily-collapsed position in the step D from the easily-collapsed positions determined in the step A, then repeating the steps B and C to fulfill fixed point protection of the easily-collapsed position, and repeating the process like this till fulfilling fixed-point protection of all of the easily- collapsed positions of the upward gas extraction borehole.
2. The method for fixed-point collapse protection of the upward gas extraction borehole according to claim 1, characterized in that the cylindrical coals are prepared by mixing pulverized coal powder and bentonite, a diameter of each of the cylindrical
BL-5247 coals is 0.8-0.9 times of a diameter of the borehole, the cylindrical coal has a length of 17000881
0.2-0.4 m, and a diameter of each of the through holes is 0.5-0.6 time of the diameter of each of the cylindrical coals.
3. The method for fixed-point collapse protection of the upward gas extraction borehole according to claim 1, characterized in that a diameter of each of the two fully unfolded barb structures is 1.1-1.12 times of the diameter of the borehole, and the barb structure and the elastic sheet are made from PVC materials.
4. The method for fixed-point collapse protection of the upward gas extraction borehole according to claim 1, characterized in that the rod body has a length of 1.15-
1.7 m, the insertion tube has a length of 0.15-0.2 m, and the connecting rod has a length of 1-15 m.
11
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010523587.XA CN111472834B (en) | 2020-06-10 | 2020-06-10 | Method for preventing upward gas extraction borehole from collapsing at fixed point |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| LU500251B1 true LU500251B1 (en) | 2021-12-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| LU500251A LU500251B1 (en) | 2020-06-10 | 2021-06-07 | Method for fixed-point collapse protection of upward gas extraction borehole |
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| CN (1) | CN111472834B (en) |
| LU (1) | LU500251B1 (en) |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102635393A (en) * | 2012-05-09 | 2012-08-15 | 中国矿业大学 | Combined hole sealing method for gas extracting and drilling delaying self-expansion capsule-paste |
| CN103195471B (en) * | 2013-04-22 | 2015-05-20 | 中国矿业大学 | Method for preventing drilling collapse of downhole coal bed |
| CN205714086U (en) * | 2016-03-07 | 2016-11-23 | 安徽理工大学 | A kind of mash gas pumping drilling fixed point aperture guard device |
| CN105804691B (en) * | 2016-03-28 | 2018-08-31 | 中国矿业大学 | A kind of gas in mine mash gas pumping drilling is without pipe method for sealing |
| CN207229158U (en) * | 2017-10-13 | 2018-04-13 | 临沂矿业集团有限责任公司 | Colliery or rock mass gas pumping test equipment |
| CN107654255B (en) * | 2017-11-06 | 2019-12-10 | 兖矿贵州能化有限公司 | Device that collapses is prevented to drainage drilling fixed point guard hole |
| CN207960570U (en) * | 2017-12-20 | 2018-10-12 | 中国矿业大学(北京) | A kind of mash gas pumping drilling Stability Maintenance material and installation aiding device |
| CN109736875B (en) * | 2018-12-11 | 2020-03-24 | 太原理工大学 | Coal seam drilling anti-collapse device and anti-collapse method |
| CN110454115A (en) * | 2019-09-10 | 2019-11-15 | 河南理工大学 | A kind of mash gas pumping drilling hole sealing device and method for sealing |
| CN111021960B (en) * | 2019-12-23 | 2021-04-02 | 山西潞安矿业集团慈林山煤业有限公司李村煤矿 | Method for improving stability of extraction drill hole of low-permeability soft coal seam |
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2020
- 2020-06-10 CN CN202010523587.XA patent/CN111472834B/en active Active
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- 2021-06-07 LU LU500251A patent/LU500251B1/en active IP Right Grant
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| Publication number | Publication date |
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| CN111472834B (en) | 2021-11-09 |
| CN111472834A (en) | 2020-07-31 |
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Effective date: 20211207 |