CN114352252A - Permeability increasing technology for long drilling hole of underworkings - Google Patents
Permeability increasing technology for long drilling hole of underworkings Download PDFInfo
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- CN114352252A CN114352252A CN202111522685.2A CN202111522685A CN114352252A CN 114352252 A CN114352252 A CN 114352252A CN 202111522685 A CN202111522685 A CN 202111522685A CN 114352252 A CN114352252 A CN 114352252A
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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 DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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
- E21B43/2607—Surface equipment specially adapted for fracturing operations
Abstract
The invention discloses an anti-reflection technology for a long borehole of an underground roadway, and belongs to the technical field of coal mine gas extraction. The permeability-increasing technology comprises prepressing preparation, fracturing construction and post-fracturing operation; when preparing before pressing: drilling a long hole in a coal rock layer roadway needing ventilation, and sealing the hole after the hole is detected to be qualified; debugging equipment and fracturing pressure on the ground, and introducing fracturing fluid for fracturing construction after the equipment trial operation meets the set pressure; during fracturing construction: the packer and the sliding sleeve are arranged at intervals to realize multi-layer partial pressure, and the injection of fracturing fluid is stopped until a plurality of cracks appear in the coal rock layer; when in post-pressing operation: pressure maintaining and water discharging are carried out by utilizing the high-pressure water pipe and the fixing device, and safety accidents are avoided from the source. The technology solves the problems of low pumping drainage efficiency, short pumping cycle and poor pumping effect of the existing coal mine, improves the gas pumping efficiency and the pumping concentration, and meets the requirement of increasing the gas permeability of the coal rock layer in a mode of high safety and mechanization degree.
Description
Technical Field
The invention belongs to the technical field of coal mine gas extraction, and particularly relates to an anti-reflection technology for a long borehole of an underground roadway.
Background
The method has the advantages that a part of horizontal coal seams under a mine have the characteristics of low hardness, softness, high gas content, poor air permeability and the like, the hole forming length of a kilometer drill hole is generally 450-550 meters, and the negative pressure is directly used for belt pumping after the drill hole construction is finished.
Disclosure of Invention
The invention provides an anti-reflection technology for a long borehole of an underground roadway, and solves the problems of low pumping and drainage efficiency, short pumping and drainage period and poor pumping and drainage effect in the prior art.
In order to solve the technical problems, the technical scheme provided by the invention is as follows: an anti-reflection technology for long drilling hole in underground tunnel includes preparing before pressing, fracturing construction and after pressing,
a pre-pressing preparation stage: starting a plurality of drilling groups with three drilling holes as a group on a driving working surface in a roadway, wherein two drilling holes positioned above are extraction holes, the drilling hole at the bottom is a fracturing hole, and the distance between the drilling layer position and a coal seam roof is 3.5 meters; the three parallel drill holes are arranged at equal intervals, and the interval is 7.5 meters; injecting No. 425 cement into the fracturing hole to seal the hole;
and (3) fracturing construction stage: connecting and assembling equipment by using a high-pressure steel pipe and a high-pressure hose, performing trial operation on the equipment on the ground, and adjusting the equipment until the equipment has the pressure-bearing performance during fracturing; carrying out pressure test on the debugged equipment based on the pressure used in the normal fracturing stage, enabling the tested fracturing equipment to be matched and enter a drill hole, dividing the tested fracturing equipment into four sections with the length of 90-160 meters, and sequentially introducing industrial salt fracturing fluid which selects 1-1.5% of salt water for fracturing construction; the discharge capacity of the absorption capacity of the coal rock layer provided with the drill hole is smaller than that of the high-pressure fracturing fluid; after each section of drilling is finished, hole sealing is carried out by using a hole sealing pipe, and the steel pipe is connected to the grid by using an armor pipe;
and (3) pressing operation: and (4) adopting a high-pressure water pipe and a fixing device to perform pressure maintaining and water discharging on the drill hole filled with the fracturing fluid.
In the fracturing construction stage, a packer and sliding sleeve are combined at intervals to perform one-time construction pressure division and multilayer, and long drilling holes in a roadway are divided into four sections to perform layer-by-layer fracturing. Five packers and five sliding sleeves are sequentially arranged at intervals to form five stages for carrying out layered fracturing.
And in the fracturing construction stage, a packer and sliding sleeve combined mode is used for carrying out one-time construction pressure division on multiple layers, and long drilling holes in a roadway are divided into multiple layers for carrying out layer-by-layer fracturing. Such fracturing equipment setting can realize the single stage fracturing in proper order of same set of pump truck to reach the seepage flow ability maximize, improve water conservancy diversion nature and productivity. The drilling position setting ensures the safety, can achieve the excellent gas permeability effect and is convenient for fracturing operation. According to the excavation technology and the actual geological condition, the length of each section is set to be 90-160 meters, so that the normal operation of fracturing work is guaranteed.
Preferably, the fracturing equipment for fracturing construction is matched with a crawler belt conveying device to enable the equipment to move in a small space and realize the backward movement. The application of the crawler belt conveying equipment improves the flexibility of the movement track of the fracturing equipment and saves the space.
Further, the high pressure fracturing fluid continues to be injected until the bottom hole pressure of the borehole is overcome and the tensile strength of the coal formation is reached. Therefore, the crack state obtained by fracturing can meet the requirement, and the aim of increasing the gas permeability is fulfilled.
Further, after the fracturing construction is finished and the pressure is relieved, a steel fracturing pipe is recycled or the quality of the fracturing pipe is changed.
Through a coal mine underground fracturing hole, a high-pressure pump set is utilized to inject high-pressure (generally 20-100 MPa) fracturing fluid into a coal rock stratum at a discharge capacity exceeding the absorption capacity of the coal rock stratum, and when the pressure is gradually increased until the ground stress near the bottom of the hole is overcome and the tensile strength of the coal rock stratum is reached, cracks are generated in the coal rock stratum. And (3) continuously injecting the high-pressure fracturing fluid, so that on one hand, original cracks in the coal rock stratum are opened, extended and communicated with each other, and on the other hand, new cracks continue to extend forwards, thereby achieving the effect of increasing the permeability coefficient of the coal rock stratum. And the recycled steel fracturing pipe or the changed fracturing pipe material can be directly crushed without mechanical friction sparks during mining exposure, thereby ensuring the safety of operation.
Compared with the prior art, the invention has the substantial characteristics that:
the process has the advantages of mature technology, reliable equipment, high intelligent degree, good safety and better implementation, and is suitable for coal seams with soft coal quality, high gas content and poor air permeability under coal mines.
1. The single-hole gas extraction concentration of the fracturing hole is improved by more than 100%, the single-hole extraction purity is improved by more than 150%, the extraction standard reaching time can be shortened by half, the gas treatment period is shortened, and the extraction rate is improved;
2. the fracturing influences the radius to be about 30 meters, the extraction concentration of other drill holes in the influenced radius is improved by more than 50%, and the extraction purity is improved by more than 50%. The estimated stope face can reduce the drilling work amount by 40 percent, improve the extraction efficiency and save the construction cost and the construction time.
Drawings
The invention is further described with reference to the following figures and detailed description.
FIG. 1 is a process flow diagram of an anti-reflection technique of the present invention.
FIG. 2 is a plan projection diagram of a coal seam directional drilling design by utilizing the permeability increasing technology of the underground roadway long drilling.
FIG. 3 is a statistical table of extraction concentration data of verification holes No. 1 and No. 2.
FIG. 4 is a statistical table of extraction concentration data of No. 1, No. 2 and No. 3 holes.
FIG. 5 is a sampling concentration curve of verification holes No. 1 and No. 2.
FIG. 6 is a hole extraction concentration curve of No. 1, No. 2 and No. 3.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that, as the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, their indicated orientations or positional relationships are based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" as appearing herein are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
Examples
An anti-reflection technology for long drilling holes in underground roadways comprises fracturing preparation, fracturing construction and post-fracturing operation.
First, preparation of fracturing
And in the fracturing preparation stage, drilling construction and hole sealing operation are sequentially carried out.
3 drill holes are designed on the tunneling working face in the auxiliary transportation roadway of the existing working face: no. 1, No. 2 and No. 3, and advanced treatment before tunneling is carried out. The hole opening distance of each hole is 7.5 meters, the final hole distance is 7.5 meters, the hole depth is 252 meters, and the distance between the drilling layer and the coal seam roof is 3.5 meters. The 3 drill holes are parallel holes, wherein the 3 drill holes are fracturing holes, the 1 drill hole and the 2 drill holes are extraction holes, the hole-opening azimuth angles of the 3 drill holes are all 0 degrees, the hole-opening inclination angles are all 0 degrees, and branch points are not reserved in the drill holes. And after drilling and forming holes, sealing holes by using a hole sealing pipe with the diameter of 153 mm, and connecting the grid by using an armored pipe with the diameter of 133 mm.
When the fracturing pipe is put down, the fracture pipe is blocked at the position of 154-155 meters, and the hole is positioned and sealed at the position. 750kg of No. 425 cement is used, and the injection amount is about 900L. Stopping injecting until the return product of the slurry return pipe is mixed cement slurry, and starting fracturing after the mixture is solidified for 48 hours.
Second, fracturing construction
And in the fracturing construction stage, the operations of assembling fracturing equipment, detecting the test running state of the equipment, selecting fracturing fluid and determining fracturing pressure are carried out.
And a DN80mm high-pressure steel pipe manifold system is selected for the fracturing. The high-pressure straight pipe plug valve mainly comprises a high-pressure straight pipe, a plug valve, a one-way valve, a reducer union, a tee joint and the like, and points needing to be pitched, leveled or turned are connected by adopting high-pressure hoses. In order to ensure the fracturing effect, an industrial salt fracturing fluid system (1-1.5% concentration saline water) is adopted for fracturing. In order to facilitate the uniform dissolution of the brine, fine-grained industrial salt is selected and added at the inlet of the water storage bag by using a funnel.
Construction discharge capacity: 1.5-1.2m3Min; the fracturing orifice is controlled by a KY25/35 type fracturing valve group or a 70MPa cock valve group; ensuring that the highest construction pressure limit is less than or equal to 25 MPa; liquid amount: the packer is injected in a grading way and is arranged at intervals with the sliding sleeve; the total construction liquid consumption is 400 and 550.
The fracturing is divided into 4 sections, wherein the first section is 154.5 meters, the second section is 133 meters, the third section is 111.5 meters, and the fourth section is 90 meters. And carrying out 42m planting on the co-injection liquid amount in the first stage of fracturing construction. And carrying out the second stage of fracturing construction by using the co-injection liquid amount 79 m. And carrying out the third fracturing construction by using the co-injection liquid amount 88 m. And carrying out the fourth stage of fracturing construction by using the co-injection liquid amount 82 m.
1. The extraction data of the No. 1 extraction hole and the No. 2 extraction hole before fracturing hole construction are shown in the attached drawing 3;
2. the extraction data of the No. 1 extraction hole, the No. 2 extraction hole and the No. 3 fracturing hole after the fracturing hole construction are shown in the attached figure 4;
3. as shown in fig. 5, the extraction concentration curves of the extraction holes No. 1 and No. 2 are compared with extraction data, and the extraction concentrations of the extraction holes No. 1 and No. 2 after the fracturing of the fracturing hole No. 3 are greatly improved, the mixing amount is not obviously changed, and the extraction purity is obviously improved;
4. through data analysis of extraction concentration curves of drill holes 1, 2 and 3 shown in fig. 6, the extraction concentration of the fracturing hole 3 is far higher than that of the extraction holes 1 and 2. The extraction mixing amount of the No. 3 fracturing hole is slightly higher than that of the No. 1 and No. 2 extraction holes, and the extraction purity is far higher than that of the No. 1 and No. 2 extraction holes.
Third, after pressing operation
The high-pressure water pipe and the fixing device are used for maintaining pressure and draining water, so that the propping agent is prevented from returning to cracks along with high-viscosity fracturing fluid, and the increasing effect is ensured.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (5)
1. An anti-reflection technology for long drilling holes of underground roadways is characterized in that: comprises pre-pressing preparation, fracturing construction and post-pressing operation,
a pre-pressing preparation stage: starting a plurality of drilling groups with three drilling holes as a group on a driving working surface in a roadway, wherein two drilling holes positioned above are extraction holes, the drilling hole at the bottom is a fracturing hole, and the distance between the drilling layer position and a coal seam roof is 3.5 meters; the three parallel drill holes are arranged at equal intervals, and the interval is 7.5 meters; injecting No. 425 cement into the fracturing hole to seal the hole;
and (3) fracturing construction stage: connecting and assembling equipment by using a high-pressure steel pipe and a high-pressure hose, performing trial operation on the equipment on the ground, and adjusting the equipment until the equipment has the pressure-bearing performance during fracturing; carrying out pressure test on the debugged equipment based on the pressure used in the normal fracturing stage, enabling the tested fracturing equipment to be matched and enter a drill hole, dividing the tested fracturing equipment into four sections with the length of 90-160 meters, and sequentially introducing industrial salt fracturing fluid which selects 1-1.5% of salt water for fracturing construction; the discharge capacity of the absorption capacity of the coal rock layer provided with the drill hole is smaller than that of the high-pressure fracturing fluid; after each section of drilling is finished, hole sealing is carried out by using a hole sealing pipe, and the steel pipe is connected to the grid by using an armor pipe;
and (3) pressing operation: and (4) adopting a high-pressure water pipe and a fixing device to perform pressure maintaining and water discharging on the drill hole filled with the fracturing fluid.
2. The anti-reflection technology for the long borehole of the underground roadway according to claim 1, characterized in that: in the fracturing construction stage, a packer and sliding sleeve are combined at intervals to perform one-time construction pressure division and multilayer, and long drilling holes in a roadway are divided into four sections to perform layer-by-layer fracturing.
3. The anti-reflection technology for the long borehole of the underground roadway according to claim 1, characterized in that: the fracturing equipment for fracturing construction is matched with a crawler belt conveying device to enable the equipment to move in a small space and realize backward movement.
4. The anti-reflection technology for the long borehole of the underground roadway according to claim 1, characterized in that: and continuously injecting the high-pressure fracturing fluid until the pressure at the bottom of the drilled hole is overcome and the tensile strength of the coal stratum is achieved.
5. The anti-reflection technology for the long borehole of the underground roadway according to claim 1, characterized in that: and after the fracturing construction is finished and the pressure is relieved, recovering the steel fracturing pipe or changing the quality of the fracturing pipe.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111522685.2A CN114352252A (en) | 2021-12-14 | 2021-12-14 | Permeability increasing technology for long drilling hole of underworkings |
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| CN202111522685.2A CN114352252A (en) | 2021-12-14 | 2021-12-14 | Permeability increasing technology for long drilling hole of underworkings |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114856512A (en) * | 2022-06-14 | 2022-08-05 | 六盘水师范学院 | Method for extracting gas from salinity crystallization permeability-increasing coal seam |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114856512A (en) * | 2022-06-14 | 2022-08-05 | 六盘水师范学院 | Method for extracting gas from salinity crystallization permeability-increasing coal seam |
| CN114856512B (en) * | 2022-06-14 | 2023-04-18 | 六盘水师范学院 | Method for extracting gas from salinity crystallization permeability-increasing coal seam |
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