Precise classification and identification and targeted grouting plugging method for drill hole fractures

Abstract

The invention discloses an accurate classification and identification and targeted grouting plugging method for drill hole fractures. The method comprises the following steps: selecting three hole groups in bedding drill holes or crossing drill holes; searching cracks in the target drill hole by using an endoscope and numbering the cracks; preliminarily identifying the through condition of the three-hole group by adopting a rough sorting detection assembly; a subdivision detection assembly is assembled in the target drill hole, the capsule hole packer B and the capsule hole packer C are made to plug the two sides of the ith crack, a detection cavity is formed, and subdivision identification is conducted on the crack type in the target drill hole; all fractures in the target drill hole are identified and recorded; a retreating mode is adopted, a discharging opening of a grouting pipe is accurately aligned with each through type crack based on the identification and recording result, and targeted grouting plugging operation is conducted; and after the cement mortar is dried, gas in the coal seam is extracted. According to the method, accurate classification identification and targeted plugging can be carried out on fractures, efficient gas extraction operation can be achieved, and the probability of safety accidents can be reduced.

Description

Technical Field

[0001] This invention belongs to the field of precise classification and effective sealing technology of borehole fracture types, specifically a method for precise classification and identification of borehole fractures and targeted grouting sealing. Background Technology

[0002] In the extraction of deep-earth oil and gas resources, in-seam drilling and cross-seam drilling are effective measures to achieve efficient extraction of deep-earth oil and gas resources, and the sealing performance of the borehole determines the extraction efficiency. Typically, after drilling, a certain pressure relief space is formed within the coal seam (or rock strata). Under the action of triaxial geostress, the borehole wall deforms due to stress compression, resulting in numerous fractures around the borehole. Furthermore, under geostress, the roadway is prone to deformation, which also leads to numerous through-type fractures within the coal seam (or rock strata). Additionally, due to mining disturbances, numerous through-type fractures also appear in the coal seam (or rock strata) ahead of the working face. The presence of these through-type fractures creates significant resistance to the extraction of deep-earth oil and gas resources. These through-type fractures are the main cause of gas leakage, not only causing the loss of negative pressure during extraction and insufficient flow momentum of oil and gas resources, but also leading to air influx into the roadway, diluting the concentration of oil and gas resources and affecting the extraction efficiency and effectiveness. Therefore, accurately classifying and identifying the fractures in the coal seam (or rock strata) around the borehole, and achieving targeted sealing of the through fractures between the roadway and the coal seam (or rock strata), is a key prerequisite for ensuring gas extraction efficiency and reducing the incidence of safety accidents, and has important practical significance for efficient and safe production in coal mines.

[0003] Current borehole fracture plugging technologies generally have limitations. Most methods fail to accurately distinguish fracture types, adopting a "general grouting and comprehensive plugging" approach. This may block effective fractures that facilitate gas flow while overlooking through fractures that connect to the roadway, resulting in poor sealing and consequently affecting the efficiency and effectiveness of oil and gas extraction. At the same time, indiscriminate plugging also leads to waste of grouting materials and increased construction costs, seriously affecting the continuity and efficiency of oil and gas extraction.

[0004] Therefore, there is an urgent need to provide a method for accurate classification and identification of borehole fractures and targeted grouting to achieve accurate identification and targeted sealing of fracture types in boreholes, ensure borehole sealing, and ensure efficient extraction of oil and gas resources. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a method for precise classification and identification of borehole fractures and targeted grouting and sealing. This method is simple to implement and has low implementation costs. It can accurately classify and identify fractures and target and seal them, enabling efficient gas extraction and helping to reduce the probability of safety accidents. It has important practical significance for efficient and safe production in coal mines.

[0006] To achieve the above objectives, this invention provides a method for accurate classification and identification of borehole fractures and targeted grouting sealing. It employs a coarse classification detection component and a fine classification detection component. The coarse classification detection component includes three detection branches and a main detection pipeline. Each detection branch includes an auxiliary injection pipe A, a capsule sealer A mounted on the auxiliary injection pipe A, an SF6 sensor A installed at the air outlet of the auxiliary injection pipe A, an auxiliary pressure gauge installed at the air inlet of the auxiliary injection pipe A, and an auxiliary valve A installed at the air inlet of the auxiliary injection pipe A. The main detection pipeline includes a main injection pipe A, a main pressure gauge A installed at the air outlet of the main injection pipe A, and a main valve A installed at the air inlet of the main injection pipe A. The outlet end is connected to the inlet end of three auxiliary filling pipes A via a four-way fitting A; the subdivided detection component includes capsule sealers B and C distributed in opposite directions, a composite filling pipe inserted in capsule sealer C, and SF6 sensors B and C respectively installed on the outer side of capsule sealer B and capsule sealer C; the composite filling pipe is provided with a gas tracer injection pipe, a gas injection pipe and a fluorescent tracer injection pipe spaced apart inside, and a pressure sensor is installed at the outlet end of the composite filling pipe. At the same time, auxiliary valves D, B and F are connected in series at the inlet ends of the gas tracer injection pipe, the gas injection pipe and the fluorescent tracer injection pipe, respectively; The method includes the following steps: Step 1: Select the target borehole in the in-layer or cross-layer drilling, and make the target borehole, together with the left adjacent borehole and the right adjacent borehole, form a three-hole group; Step 2: Insert the endoscope into the target borehole and search for all fractures one by one from the borehole opening to the set depth. The total number of fractures (5) is recorded as follows: k Record the location and number of each crack; Step 3: Conduct a preliminary assessment of the continuity of the three-hole group; install the coarse-scale testing component in the three-hole group, open the main valve A and the three auxiliary valves A, and simultaneously pressurize the three boreholes with air through the main injection pipe A. When the reading of the auxiliary pressure gauge reaches the preset pressure value A, close the corresponding auxiliary valve A. After all three auxiliary valves A are closed, close the main valve A, and then open the three auxiliary valves A again; observe the reading of the main pressure gauge A within the set observation time A. P , if the number is shown P If the decrease is ≤5%, then the three-hole group does not connect with the roadway and is judged as a non-connecting hole group. If the reading... P If the decrease is greater than 5%, then the three-hole group is connected to the roadway and is judged as a through-type hole group; Step 4: Detailed identification of the fracture types in the target borehole; Remove the four-way fitting A, retain the two detection branches in the left and right adjacent boreholes, and replace the detection branch in the target borehole with a subdivision detection component, so that the capsule sealers B and C seal the first borehole. i The two sides of the crack form a detection cavity; S1: If the three-hole group is a non-through-hole group, it is further identified through the following process: S11: Open auxiliary valve B and inflate the detection chamber with air through the air injection pipe. When the preset pressure value B is reached, close auxiliary valve B; within the set observation time B, sense the pressure value through the air pressure sensor. P Ci If the pressure value P Ci If the decrease is ≤5%, then the first one is judged. i The fracture is classified as a Class 1 fracture and recorded as a non-penetrating fracture. If the pressure value... P Ci If the decrease is greater than 5%, then execute S12; S12: Open auxiliary valve D, inject tracer SF6 into the detection chamber through the gas tracer injection pipe. Simultaneously, within the set detection time A, use SF6 sensor A to detect two adjacent boreholes, and use SF6 sensors B and C to detect the outside of the detection chamber. If tracer SF6 is detected in any adjacent borehole, then the detection is determined to be... i The fracture is classified as a Class 2 fracture and recorded as a non-penetrating fracture; if tracer SF6 is not detected in any adjacent borehole, but is detected outside the detection chamber, then the fracture is classified as a Class 2 fracture. i The cracks are classified as Class 3 cracks and recorded as non-penetrating cracks; S2: If the three-hole group is a through-hole group, it is further identified through the following process: S21: Open auxiliary valve D and inject tracer SF6 into the detection chamber through the gas tracer injection pipe. Simultaneously, within the set detection time B, the roadway is detected using an SF6 tracer detector, and the outside of the detection chamber is detected using SF6 sensors B and C. If no tracer SF6 is detected in the roadway, then the following steps are determined: i The crack is one of the types 1 to 3, and S1 is repeated until the first crack is determined. i The type of fracture; if tracer SF6 is detected in the roadway, and tracer SF6 is also detected outside the detection chamber, then the fracture is determined to be the first fracture. i The crack is classified as a Class 5 crack and recorded as a through crack. If tracer SF6 is not detected outside the detection chamber, then S22 is executed. S22: Open auxiliary valve F, inject fluorescent tracer into the detection chamber through the fluorescent tracer injection tube, and simultaneously, within the set detection time C, detect the roadway using a fluorescent tracer detector; if fluorescent tracer is detected only at one location in the roadway, then the first detection is determined to be... i The fracture is classified as a Class 4 fracture and recorded as a through fracture; if fluorescent tracer is detected at two locations in the roadway, then the fracture is classified as Class 4. i The fractures were classified as Class 6 fractures and recorded as continuous fractures; Step 5: Complete drilling all holes in the target borehole following the method described in Step 4. k Identification and recording of cracks; Step Six: Insert the grouting pipe into the target borehole and, using a backward motion, precisely align the outlet of the grouting pipe with each through-type fracture based on the identification and recording results. Simultaneously control the grouting pump to start working and perform targeted grouting and sealing operations on each through-type fracture one by one until all through-type fracture sealing operations are completed. Then, control the grouting pump to stop. Step 7: After the cement mortar dries, establish the gas connection between the extraction pipeline network and the three-hole group, and then start the gas extraction device to extract gas from the coal seam.

[0007] As a preferred embodiment, the extraction pipeline network includes branch connecting pipelines, a capsule sealer D, an auxiliary valve C, a main connecting pipeline, a main pressure gauge B, a main valve B, and an extraction pipe; the capsule sealer D is fitted onto the outside of the air inlet section of the branch connecting pipeline; the auxiliary valve C is connected in series to the air outlet section of the branch connecting pipeline; the air inlet end of the main connecting pipeline is connected to the air outlet ends of the three branch connecting pipelines via a four-way fitting B; the main pressure gauge B is installed on the air inlet section of the main connecting pipeline; the main valve B is connected in series to the air outlet section of the main connecting pipeline; and the air inlet end of the extraction pipe is connected to the air outlet end of the main connecting pipeline.

[0008] As a preferred embodiment, in step four, S21, the SF6 tracer detector is installed on the tunnel wall.

[0009] As a preferred embodiment, in step four, S22, the optical tracer detector is installed on the tunnel wall.

[0010] As a preferred option, in step two, while numbering each crack, the depth information of each crack is recorded simultaneously.

[0011] This invention provides a method for precise classification and identification of borehole fractures and targeted grouting for sealing. First, by selecting a three-hole group and then selecting the central borehole for fracture detection and recording, preliminary identification of fracture continuity type can be efficiently achieved. Next, a coarse screening component is used to coarsely screen the fracture types, accurately and efficiently determining the connection status between the fracture and the roadway. Then, a finer detection component is used in conjunction with a tracer-based detection component to accurately and efficiently determine whether the fractures in the surrounding coal seam (or rock strata) are continuous fractures or... These are non-penetrating fractures. Based on this, targeted sealing is performed only on fractures that connect with the roadway. This can precisely block penetrating fractures that communicate with the roadway, achieving targeted sealing of penetrating fractures between the roadway and the coal seam (or rock strata). This effectively ensures borehole sealing, which not only improves the efficiency and effectiveness of oil and gas extraction but also effectively saves grouting materials and construction time, and helps reduce construction costs, ensuring the continuity and efficiency of oil and gas extraction. Finally, gas extraction is carried out through the extraction pipeline network.

[0012] This method is simple to implement and has low implementation costs. It can accurately classify and identify fissures and target them for sealing, enabling efficient gas extraction and helping to reduce the probability of safety accidents. It has important practical significance for efficient and safe coal mine production. Attached Figure Description

[0013] Figure 1 This is a flowchart of the present invention; Figure 2 This is a schematic diagram of in-bedding drilling in this invention; Figure 3 This is a schematic diagram illustrating the classification of Class 1 fractures in cross-layer drilling in this invention; Figure 4 This is a schematic diagram illustrating the classification of two types of fractures in cross-layer drilling in this invention; Figure 5 This is a schematic diagram of the classification of three types of fractures in cross-layer drilling in this invention; Figure 6 This is a schematic diagram of the classification of four types of fractures in cross-layer drilling in this invention; Figure 7 This is a schematic diagram of the classification of five types of fractures in cross-layer drilling in this invention; Figure 8 This is a schematic diagram of the classification of six types of fractures in cross-layer drilling in this invention; Figure 9 This is a schematic diagram of the coarse-grained detection component in this invention; Figure 10 This is a schematic diagram of the preliminary identification process using the coarse-score detection component in this invention; Figure 11 This is a schematic diagram of the subdivision detection component in the target borehole in this invention; Figure 12 This is a schematic diagram illustrating the fine-grained identification status of a borehole group using a fine-grained detection component in conjunction with two detection branches in a coarse-grained detection component. Figure 13 This is a schematic diagram of the extraction of the three-hole group after the sealing treatment according to the present invention.

[0014] In the diagram: 1. Three-hole group; 2. Target borehole; 3. Left adjacent borehole; 4. Right adjacent borehole; 5. Fracture; 6. Auxiliary valve C; 7. Main pressure gauge B; 8. Main valve B; 9. Roadway wall; 10. Extraction pipe; 11. Roadway; 12. Coal seam or rock strata; 13. In-seam borehole; 14. Working face intake airway; 15. Working face return airway; 16. Capsule sealer B; 17. Detection chamber; 18. Gas pressure sensor; 19. Composite injection pipe; 20. Gas tracer injection pipe; 21. Gas injection pipe; 22. Fluorescent tracer injection pipe. 23. Branch connecting pipe; 24. Main connecting pipe; 25. Capsule sealer C; 26. Auxiliary filling pipe A; 27. Capsule sealer A; 28. Auxiliary pressure gauge; 29. ​​Auxiliary valve A; 30. Main filling pipe A; 31. Main pressure gauge A; 32. Main valve A; 33. Capsule sealer D; 34. Auxiliary valve B; 35. SF6 sensor A; 36. SF6 sensor B; 37. SF6 sensor C; 38. Auxiliary valve D; 39. Auxiliary valve F; 40. Four-way fitting A; 41. Four-way fitting B; 42. Through-layer drilling. Detailed Implementation

[0015] The invention will now be further described with reference to the accompanying drawings.

[0016] like Figures 1 to 13As shown, this invention provides a method for accurate classification and identification of borehole fractures and targeted grouting sealing. It employs a coarse classification detection component and a fine classification detection component. The coarse classification detection component includes three detection branches and a main detection pipeline. Each detection branch includes an auxiliary injection pipe A26, a capsule sealer A27 mounted on the auxiliary injection pipe A26, an SF6 sensor A35 installed at the air outlet of the auxiliary injection pipe A26, an auxiliary pressure gauge 28 installed at the air inlet of the auxiliary injection pipe A26, and an auxiliary valve A29 installed at the air inlet of the auxiliary injection pipe A26. The main detection pipeline includes a main injection pipe A30, a main pressure gauge A31 installed at the air outlet of the main injection pipe A30, and a main valve A32 installed at the air inlet of the main injection pipe A30. The air outlet of the main injection pipe A30 is connected to a four-way fitting A. 40 is connected to the air inlet of three auxiliary filling tubes A26; the subdivision detection component includes capsule sealers B16 and C25 distributed in opposite directions, a composite filling tube 19 inserted in the capsule sealer C25, and SF6 sensors B36 and C37 respectively installed on the outer side of the capsule sealer B16 and the outer side of the capsule sealer C25; the composite filling tube 19 is provided with gas tracer injection tube 20, gas injection tube 21 and fluorescent tracer injection tube 22 spaced apart inside, and a pressure sensor 18 is installed at the air outlet of the composite filling tube 19. At the same time, auxiliary valves D38, B34 and F39 are connected in series at the air inlet of the gas tracer injection tube 20, gas injection tube 21 and fluorescent tracer injection tube 22 respectively; The method includes the following steps: Step 1: Select the target borehole 2 in the in-layer borehole 13 or the cross-layer borehole 42, and make the target borehole 2, together with the left adjacent borehole 3 and the right adjacent borehole 4, form a three-hole group 1. Figure 2 A schematic diagram showing the distribution of several in-seam boreholes 13 located between the intake airway 14 and the return airway 15 of the working face in the coal seam or rock strata 12 is presented. Step 2: Insert the endoscope into the target borehole 2 and search for all fractures 5 one by one from the borehole opening to the set depth. The total number of fractures (5) is recorded as follows: k Record the location of each crack and number it; Step 3: As Figure 9 and Figure 10As shown, a preliminary identification of the continuity of the three-hole group 1 is performed. A coarse-scale detection component is installed in the three-hole group 1, with the three detection branches extending into the three boreholes respectively. The borehole openings are sealed using the capsule sealing device A27. The main valve A32 and the three auxiliary valves A29 are opened, and air is synchronously injected into the three boreholes using the main injection pipe A30. When the reading of the auxiliary pressure gauge 28 reaches the preset pressure value A, the corresponding auxiliary valve A29 is closed. After all three auxiliary valves A29 are closed, the main valve A32 is closed, and then the three auxiliary valves A29 are opened again. The reading of the main pressure gauge A31 is observed within the set observation time A. P , if the number is shown P If the decrease is ≤5%, then the three-hole group 1 does not have a connection with roadway 11, and is judged as a non-connecting hole group. That is, all the fractures 5 in the three-hole group 1 are only type 1 to 3 fractures, and there are no fractures 5 that connect with roadway 11. If the reading P If the decrease is greater than 5%, then the three-hole group 1 is connected to the roadway 11 and is judged as a connected hole group. That is, the existence of type 1 to 3 fractures cannot be ruled out in the three-hole group 1, but it can be determined that there are type 4 to 6 fractures connected to the roadway 11 in the three-hole group 1. The fracture classification is shown in Table 1.

[0017] Type 1 fractures: These fractures are connected to only a single borehole and do not extend to other adjacent boreholes or penetrate the tunnel wall.

[0018] Type 2 fractures: With the target borehole 2 as the intermediate node, a communication channel is formed between the borehole and the fracture, but the end of the fracture 5 will not touch the roadway wall 9.

[0019] Type 3 fractures: These fractures extend only within a single borehole and exhibit multiple reversals and loops, such as annular fractures, without penetrating adjacent boreholes or tunnel walls.

[0020] Type 4 fractures: They simultaneously connect adjacent boreholes and penetrate the tunnel wall 9, forming a communication network of "tunnel - fracture - multiple boreholes".

[0021] Type 5 fracture: One end of fracture 5 communicates with the target borehole 2, and can pass through the borehole once or extend multiple times within the borehole. The other end penetrates the tunnel wall 9, but does not communicate with other adjacent boreholes.

[0022] Type 6 fractures: Both ends of fracture 5 are connected to the tunnel wall 9, and its extension path will pass through one or more boreholes. The target borehole 2 is only one of the "passage points" of fracture 5.

[0023] Step 4: Detailed identification of the type 5 of fracture 5 in target borehole 2; like Figure 11 and Figure 12As shown, remove the four-way fitting A4, retain the two detection branches in the left adjacent borehole 3 and the right adjacent borehole 4, and replace the detection branch in the target borehole 2 with a subdivision detection component, so that the capsule sealer B16 and the capsule sealer C25 seal the first borehole. i Both sides of the crack 5 form a detection cavity 17; ensuring that only the first crack exists in the detection cavity 17. i There is one crack 5, and no other cracks 5; S1: If the three-hole group 1 is a non-through-hole group, it is identified through the following process: S11: As Figure 11 and Figure 12 As shown, the auxiliary valve B34 is opened, and air is injected into the detection chamber 17 through the air injection pipe 21. When the preset pressure value B is reached, the auxiliary valve B34 is closed; the pressure value is sensed by the air pressure sensor 18 within the set observation time B. P Ci If the pressure value P Ci If the decrease is ≤5%, then the first one is judged. i Crack 5 is classified as a Class 1 crack and recorded as a non-penetrating crack. If the pressure value... P Ci If the decrease is greater than 5%, then execute S12; S12: As Figure 11 and Figure 12 As shown, the auxiliary valve D38 is opened, and a set amount of tracer SF6 is injected into the detection chamber 17 through the gas tracer injection pipe 20. Simultaneously, within a set detection time A, the SF6 sensor A35 detects two adjacent boreholes (left adjacent borehole 3 and right adjacent borehole 4), and the SF6 sensors B36 and C37 detect the outside of the detection chamber 17. If tracer SF6 is detected in any adjacent borehole, then the first borehole is considered to be in the first detection chamber. i Fracture 5 is classified as a Class 2 fracture and recorded as a non-penetrating fracture; if tracer SF6 is not detected in any adjacent borehole, but is detected outside detection chamber 17, then the fracture is classified as a Class 2 fracture. i Crack 5 is classified as a Class 3 crack and is recorded as a non-penetrating crack; S2: If the three-hole group 1 is a through-hole group, it is identified through the following process: S21: As Figure 11 and Figure 12 As shown, the auxiliary valve D38 is opened, and a set amount of tracer SF6 is injected into the detection chamber 17 through the gas tracer injection pipe 20. Simultaneously, within the set detection time B, the SF6 tracer detector detects the roadway 11, and the SF6 sensors B36 and C37 detect the outside of the detection chamber 17. If no tracer SF6 is detected in the roadway 11, then the first detection is considered complete. iCrack 5 is one of the types 1 to 3 cracks, and S1 is repeated until the first crack is determined. i The type of crack 5; if tracer SF6 is detected in roadway 11, and tracer SF6 is also detected outside detection chamber 17, then the crack is determined to be the first one. i Crack 5 is a type 5 crack and is recorded as a through crack. If tracer SF6 is not detected outside the detection chamber 17, then S22 is executed. S22: As Figure 11 and Figure 12 As shown, the auxiliary valve F39 is opened, and a set amount of fluorescent tracer is injected into the detection chamber 17 through the fluorescent tracer injection tube 22. Simultaneously, within a set detection time C, the fluorescent tracer detector is used to detect the tunnel 11. If fluorescent tracer is detected only at one location in the tunnel 11, then the first detection is considered complete. i Crack 5 is classified as a Class 4 crack and recorded as a through crack; if fluorescent tracer is detected at two locations in roadway 11, then the crack is classified as Class 4. i Crack 5 is classified as a type 6 crack and is recorded as a through crack; Step 5: Complete drilling all holes in target borehole 2 in the manner described in Step 4. k Identification and recording of crack 5; Step 6: Insert the grouting pipe into the target borehole 2, and use a backward method. Based on the identification and recording results, accurately align the outlet of the grouting pipe with each through-type fracture, and simultaneously control the grouting pump to start working. Perform targeted grouting and sealing operations on each through-type fracture one by one until all through-type fracture sealing operations are completed, and then control the grouting pump to stop. Step 7: After the cement mortar dries, establish the gas connection between the extraction pipeline network and the three-hole group 1, and then start the gas extraction device to extract the gas in the coal seam.

[0024] As a preferred embodiment, the extraction pipeline network includes branch connecting pipelines 23, capsule sealer D33, auxiliary valve C6, main connecting pipeline 24, main pressure gauge B7, main valve B8, and extraction pipe 10; the capsule sealer D33 is fitted outside the air inlet section of the branch connecting pipeline 23; the auxiliary valve C6 is connected in series to the air outlet section of the branch connecting pipeline 23; the air inlet end of the main connecting pipeline 24 is connected to the air outlet ends of the three branch connecting pipelines 23 through a four-way fitting B41; the main pressure gauge B7 is installed on the air inlet section of the main connecting pipeline 24; the main valve B8 is connected in series to the air outlet section of the main connecting pipeline; and the air inlet end of the extraction pipe 10 is connected to the air outlet end of the main connecting pipeline 24.

[0025] As a preferred embodiment, in step four, S21, the SF6 tracer detector is installed on the tunnel wall 9.

[0026] As a preferred embodiment, in step four, S22, the optical tracer detector is installed on the tunnel wall 9.

[0027] As a preferred option, in step two, while numbering each crack 5, the depth information of each crack 5 is recorded simultaneously.

[0028] This invention provides a method for precise classification and identification of borehole fractures and targeted grouting for sealing. First, by selecting a three-hole group and then selecting the central borehole for fracture detection and recording, preliminary identification of fracture continuity type can be efficiently achieved. Next, a coarse screening component is used to coarsely screen the fracture types, accurately and efficiently determining the connection status between the fracture and the roadway. Then, a finer detection component is used in conjunction with a tracer-based detection component to accurately and efficiently determine whether the fractures in the surrounding coal seam (or rock strata) are continuous fractures or... These are non-penetrating fractures. Based on this, targeted sealing is performed only on fractures that connect with the roadway. This can precisely block penetrating fractures that communicate with the roadway, achieving targeted sealing of penetrating fractures between the roadway and the coal seam (or rock strata). This effectively ensures borehole sealing, which not only improves the efficiency and effectiveness of oil and gas extraction but also effectively saves grouting materials and construction time, and helps reduce construction costs, ensuring the continuity and efficiency of oil and gas extraction. Finally, gas extraction is carried out through the extraction pipeline network.

[0029] This method is simple to implement and has low implementation costs. It can accurately classify and identify fissures and target them for sealing, enabling efficient gas extraction and helping to reduce the probability of safety accidents. It has important practical significance for efficient and safe production in coal mines.

Claims

1. A method for accurate classification and identification of drilling fissures and targeted grouting plugging, characterized in that, The application discloses a detection device for detecting whether a drill hole is connected with a roadway, and belongs to the technical field of drill hole detection. The method comprises the following steps: Step one: select a target drill hole (2) in a bedding drill hole (13) or a cross-layer drill hole (42), and make the target drill hole (2) and left and right adjacent drill holes (3 and 4) form a three-hole group (1) together; Step two: insert an endoscope into the target drill hole (2), and find all fissures (5) from the orifice to a set depth range one by one, the total number of the fissures (5) is recorded as k, and the position of each fissure (5) is recorded and numbered; Step three: preliminarily identify the through condition of the three-hole group (1); load a coarse detection assembly into the three-hole group (1), open the main valve A (32) and the three auxiliary valves A (29), simultaneously inflate the interiors of the three drill holes by using the main filling pipe A (30), when the reading of the auxiliary pressure gauge (28) reaches a preset pressure value A, close the corresponding auxiliary valve A (29), after the three auxiliary valves A (29) are all closed, close the main valve A (32), and then open the three auxiliary valves A (29) again; observe the reading P of the main pressure gauge A (31) within a set observation time A, if the reading P decreases by no more than 5%, the three-hole group (1) does not exist the condition of being connected with the roadway (11), and is determined as a non-through hole group, if the reading P decreases by more than 5%, the three-hole group (1) exists the condition of being connected with the roadway (11), and is determined as a through hole group. Step four: Subdivide the type of fissure (5) in the target borehole (2); Remove four-way pipe A (4), keep two detection branches in the left adjacent borehole (3) and the right adjacent borehole (4), replace the detection branch in the target borehole (2) with a subdivided detection assembly, and make the capsule seal B (16) and the capsule seal C (25) block on both sides of the ith fissure (5) to form a detection cavity (17); S1: If the three-hole group (1) is a non-penetrating hole group, the subdivision identification is performed by the following process: S11: open the auxiliary valve B (34), fill the detection cavity (17) with gas through the gas injection pipe (21), and close the auxiliary valve B (34) when the preset pressure value B is reached; sense the pressure value P through the gas pressure sensor (18) within the set observation time B Ci , if the pressure value P Ci decreases by ≤5%, determine that the i-th fracture (5) is a Class 1 fracture, and record it as a non-penetrating fracture, and if the pressure value P Ci decreases by >5%, perform S12; S12: Open the auxiliary valve D (38), inject the tracer SF6 into the detection cavity (17) through the gas tracer injection pipe (20), and at the same time, detect the two adjacent boreholes through the SF6 sensor A (35) within the set detection time A, and detect the outside of the detection cavity (17) through the SF6 sensor B (36) and the SF6 sensor C (37); If the tracer SF6 is detected in any adjacent borehole, it is determined that the ith fissure (5) is a 2-type fissure, and it is recorded as a non-penetrating fissure; If the tracer SF6 is not detected in any adjacent borehole, and at the same time, the tracer SF6 is detected outside the detection cavity (17), it is determined that the ith fissure (5) is a 3-type fissure, and it is recorded as a non-penetrating fissure; S2: If the three-hole group (1) is a penetrating hole group, the subdivision identification is performed by the following process: S21: Open the auxiliary valve D (38), inject the tracer SF6 into the detection cavity (17) through the gas tracer injection pipe (20), and at the same time, detect the roadway (11) through the SF6 tracer detector within the set detection time B, and detect the outside of the detection cavity (17) through the SF6 sensor B (36) and the SF6 sensor C (37); If the tracer SF6 is not detected in the roadway (11), it is determined that the ith fissure (5) is one of the 1-3 type fissures, and S1 is re-executed until the type of the ith fissure (5) is determined; If the tracer SF6 is detected in the roadway (11), and the tracer SF6 is detected outside the detection cavity (17), it is determined that the ith fissure (5) is a 5-type fissure, and it is recorded as a penetrating fissure, and when the tracer SF6 is not detected outside the detection cavity (17), S22 is executed; S22: Close the auxiliary valve F (39), inject the fluorescent tracer into the detection cavity (17) through the fluorescent tracer injection pipe (22), and at the same time, detect the roadway (11) through the fluorescent tracer detector within the set detection time C; If the fluorescent tracer is detected only in one place in the roadway (11), it is determined that the ith fissure (5) is a 4-type fissure, and it is recorded as a penetrating fissure; If the fluorescent tracer is detected in two places in the roadway (11), it is determined that the ith fissure (5) is a 6-type fissure, and it is recorded as a penetrating fissure; Step five: Complete the identification and recording of all k fissures (5) in the target borehole (2) according to the method in step four; Step six: extend the grouting pipe into the target borehole (2), use the retreating method, based on the identification and recording results, accurately align the discharge port of the grouting pipe with each through-type fracture, simultaneously control the grouting pump to start working, and perform targeted grouting and plugging operation on each through-type fracture one by one, until all through-type fracture plugging operations are completed, and the grouting pump is stopped; Step seven: after the cement mortar is dried, establish the gas path connection between the extraction pipe network and the three-hole group (1), and then start the gas extraction device to extract the gas in the coal seam.

2. The method according to claim 1, wherein, The extraction pipe network comprises a branch communication pipeline (23), a capsule hole sealer D (33), an auxiliary valve C (6), a main communication pipeline (24), a main pressure gauge B (7), a main valve B (8) and an extraction pipe (10); the capsule hole sealer D (33) is sleeved outside the gas inlet section of the branch communication pipeline (23); the auxiliary valve C (6) is connected in series on the gas outlet section of the branch communication pipeline (23); the gas inlet end of the main communication pipeline (24) is connected with the gas outlet ends of the three branch communication pipelines (23) through a four-way pipe fitting B (41); the main pressure gauge B (7) is installed on the gas inlet section of the main communication pipeline (24); the main valve B (8) is connected in series on the gas outlet section of the main communication pipeline; the gas inlet end of the extraction pipe (10) is connected with the gas outlet end of the main communication pipeline (24).

3. The method according to claim 1, wherein, In S21 of step four, the SF6 tracer detector is installed on the roadway wall (9).

4. The method according to claim 1, wherein, In S22 of step four, the optical tracer detector is installed on the roadway wall (9).

5. The method of claim 1, wherein the method further comprises: In step two, during the numbering of each fracture (5), the depth information of each fracture (5) is recorded synchronously. In step two, during the numbering of each fracture (5), the depth information of each fracture (5) is recorded synchronously.

Images