A method and system for determining the timing of hydraulic fracturing roof cutting and pressure relief in a dynamic pressure roadway

Abstract

The present invention provides a method and system for determining the hydraulic fracturing roof cutting and pressure relief timing in dynamic pressure roadways, including: obtaining the original rock stress of multiple fracturing boreholes in a preset mining area of a coal mine; re-collecting the mining stress of multiple fracturing boreholes; calculating the maximum principal stress of each fracturing borehole respectively to determine the first included angle between the azimuth angle of the maximum principal stress and the axial direction of the roadway in the preset mining area of the coal mine, and the second included angle between the dip angle of the maximum principal stress and the direction perpendicular to the axial direction of the roadway; obtaining the preset minimum range of the first included angle and the second included angle, and determining several fracturing boreholes corresponding to the preset minimum range; determining the distance of several fracturing boreholes in front of the working face in the preset mining area of the coal mine as the optimal fracturing timing for fracturing operations. The present invention analyzes the stress evolution law of the rock formation, thereby obtaining the optimal fracturing timing of the rock formation, realizing that the cracks extend as much as possible along the vertical direction and the axial direction of the roadway, achieving the best roof cutting effect, and thus controlling the deformation of the dynamic pressure roadway.

Description

Technical Field

[0001] The present invention relates to the technical field of mine pressure and strata control, and particularly to a method and system for determining the hydraulic fracturing roof cutting and pressure relief timing of dynamic pressure roadways. Background Art

[0002] During the coal mining process, due to the large number of coal mining-induced roadways, the roadways affected by mining are severely deformed. Merely adopting means such as strengthening support and increasing coal pillars is difficult to effectively control the roadway deformation. It is generally believed that the long lateral overhanging roof distance in the goaf is the main reason for the dynamic pressure roadway to be in a high stress area and continue to deform. With the introduction of the hydraulic fracturing roof cutting technology in the coal mining field, it has been gradually widely applied in the deformation control of dynamic pressure roadways in recent years. The main principle is to pre-fracture the upper hard and difficult-to-collapse roof in advance by using the hydraulic fracturing method in front of the working face mining position. After the working face is mined, the upper hard and difficult-to-collapse roof will collapse towards the goaf more easily and quickly, thereby reducing the length and time of the overhanging roof, minimizing the lateral high stress concentration caused by the long-distance and large-area overhanging roof as much as possible, and then reducing the surrounding rock stress of the external dynamic pressure roadway and controlling the degree of roadway deformation and damage.

[0003] Although the hydraulic fracturing is used more in the current methods of pre-fracturing and roof cutting of hard roofs, due to the ever-changing geological conditions and mining conditions, the effects of many hydraulic fracturing pre-fracturing and roof cutting are very poor and fail to play the role of pressure relief and protection. The main reasons are that the setting of the fracturing holes is very random, the understanding of the propagation law of the hydraulic fracturing cracks is unclear, what the propagation direction of the cracks is after hydraulic fracturing, and whether it can play the role of roof cutting cannot be accurately obtained. Therefore, the hydraulic fracturing roof cutting and pressure relief effect cannot be guaranteed. Summary of the Invention

[0004] The present invention provides a method and system for determining the hydraulic fracturing roof cutting and pressure relief timing of dynamic pressure roadways to solve the defect in the prior art that the setting of the fracturing holes for the hydraulic fracturing pre-fracturing and roof cutting is relatively random, resulting in the inability to obtain the propagation law of the hydraulic fracturing cracks and thus the inability to estimate the propagation direction of the cracks after hydraulic fracturing.

[0005] In a first aspect, the present invention provides a method for determining the hydraulic fracturing roof cutting and pressure relief timing of dynamic pressure roadways, including:

[0006] Using the original hollow inclusion, obtaining the in-situ stress of multiple fracturing boreholes in the preset coal mining area.

[0007] Using the new hollow inclusion, re-collecting the mining-induced stress of the multiple fracturing boreholes multiple times.

[0008] Based on the in-situ stress and the mining-induced stress, calculate the maximum principal stress of each fracturing borehole respectively to determine the first included angle between the azimuth angle of the maximum principal stress and the axial direction of the roadway in the preset mining area of the coal mine, and the second included angle between the dip angle of the maximum principal stress and the direction perpendicular to the axial direction of the roadway;

[0009] Obtain the preset minimum range of the first included angle and the second included angle, and determine several fracturing boreholes corresponding to the preset minimum range;

[0010] Determine that the advanced distance of the several fracturing boreholes from the working face in the preset mining area of the coal mine is the optimal fracturing time for fracturing operations.

[0011] According to a method for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway provided by the present invention, before obtaining the in-situ stress of multiple fracturing boreholes in the preset mining area of the coal mine by using the original hollow inclusion, it further includes:

[0012] Starting from the roof rock stratum, drill a plurality of fracturing boreholes downward at a preset interval distance close to the projection direction of the coal pillar and away from the working face, and stop at the top of the roadway;

[0013] Among them, the plurality of fracturing boreholes are arranged at equal intervals, and the advancing direction of the plurality of fracturing boreholes is consistent with the advancing direction of the working face mining.

[0014] According to a method for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway provided by the present invention, obtaining the in-situ stress of multiple fracturing boreholes in the preset mining area of the coal mine by using the original hollow inclusion includes:

[0015] Install hollow inclusions in the plurality of fracturing boreholes;

[0016] Relieve the stress of the plurality of fracturing boreholes and withdraw the hollow inclusions;

[0017] Calculate and obtain the in-situ stress of the plurality of fracturing boreholes.

[0018] According to a method for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway provided by the present invention, using a new hollow inclusion to repeatedly collect the mining-induced stress of the plurality of fracturing boreholes includes:

[0019] Install the new hollow inclusion in the plurality of fracturing boreholes and grout and seal the new hollow inclusion;

[0020] After the grouted and sealed hollow inclusion is coupled with the rock mass, measure and calculate the mining-induced stress of the plurality of fracturing boreholes.

[0021] A method for determining the timing of roof cutting and pressure relief by hydraulic fracturing in dynamic pressure roadway provided by the present invention, based on the in-situ stress and the mining-induced stress, calculates the maximum principal stress of each fracturing borehole respectively, including:

[0022] Vectorially superpose the in-situ stress and the mining-induced stress to obtain the maximum principal stress.

[0023] A method for determining the timing of roof cutting and pressure relief by hydraulic fracturing in dynamic pressure roadway provided by the present invention, obtaining the preset minimum range of the first included angle and the second included angle, and determining several fracturing boreholes corresponding to the preset minimum range, including:

[0024] If it is determined that the first included angle corresponding to any fracturing borehole is close to the axial direction of the roadway, and the corresponding second included angle is close to the direction perpendicular to the axial direction of the roadway, and both the first included angle and the second included angle are within the preset minimum range, then determine the position corresponding to the any fracturing borehole as the starting value of the distance ahead of the working face;

[0025] If it is determined that the first included angle corresponding to any other fracturing borehole is far from the axial direction of the roadway, and the corresponding second included angle is far from the direction perpendicular to the axial direction of the roadway, and both the first included angle and the second included angle are within the preset minimum range, then determine the position corresponding to the any other fracturing borehole as the ending value of the distance ahead of the working face.

[0026] A method for determining the timing of roof cutting and pressure relief by hydraulic fracturing in dynamic pressure roadway provided by the present invention, the multiple fracturing boreholes are at least 2.

[0027] In a second aspect, the present invention also provides a system for determining the timing of roof cutting and pressure relief by hydraulic fracturing in dynamic pressure roadway, including:

[0028] An acquisition module, configured to use original hollow inclusion to acquire the in-situ stress of multiple fracturing boreholes in a preset mining area of a coal mine;

[0029] A collection module, configured to use new hollow inclusion to repeatedly collect the mining-induced stress of the multiple fracturing boreholes;

[0030] A calculation module, configured to calculate the maximum principal stress of each fracturing borehole respectively based on the in-situ stress and the mining-induced stress, so as to determine the first included angle between the azimuth angle of the maximum principal stress and the axial direction of the roadway in the preset mining area of the coal mine, and the second included angle between the dip angle of the maximum principal stress and the direction perpendicular to the axial direction of the roadway;

[0031] A processing module, configured to obtain the preset minimum range of the first included angle and the second included angle, and determine several fracturing boreholes corresponding to the preset minimum range;

[0032] A determination module, configured to determine that the advanced working face distance of the several fracturing boreholes in the preset mining area of the coal mine is the optimal fracturing timing for fracturing operations.

[0033] In a third aspect, the present invention further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the method for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway as described in any one of the above.

[0034] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the method for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway as described in any one of the above.

[0035] In a fifth aspect, the present invention further provides a computer program product, including a computer program. When the computer program is executed by a processor, it implements the method for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway as described in any one of the above.

[0036] The method and system for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway provided by the present invention obtain relatively accurate values such as the original rock stress, mining stress, and their variation laws through measurement, analyze the stress evolution law of the rock formation, thereby obtaining the optimal fracturing timing of the rock formation, realizing that the cracks extend as much as possible along the vertical direction and the axial direction of the roadway, achieving the best roof cutting effect, and thus controlling the deformation of the dynamic pressure roadway. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0038] Figure 1 It is a schematic flowchart of the method for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway provided by the present invention;

[0039] Figure 2 It is a schematic diagram of the layout of typical fracturing boreholes provided by the present invention;

[0040] Figure 3 It is a schematic plan view of the positional relationship between the fracturing borehole and the working face provided by the present invention;

[0041] Figure 4 It is a schematic diagram of the installation position of the hollow inclusion stress gauge provided by the present invention;

[0042] Figure 5Schematic diagram of the optimal advanced distance and the optimal fracturing timing provided by the present invention;

[0043] Figure 6 Schematic structural diagram of the system for determining the hydraulic fracturing roof cutting and pressure relief timing of the dynamic pressure roadway provided by the present invention;

[0044] Figure 7 Schematic structural diagram of the electronic device provided by the present invention. Detailed implementation manners

[0045] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention.

[0046] Aiming at the problem that the evolution law of the rock stratum stress state under mining conditions is unclear, which affects the effect of dynamic pressure hydraulic fracturing roof cutting and pressure relief, the present invention proposes a method for analyzing and measuring the evolution law of the rock stratum stress state under mining conditions based on the stress relief method, so as to quantitatively obtain the advanced distance corresponding to the optimal fracturing timing in front of the working face, and achieve reasonable selection of the fracturing timing to control the crack propagation direction.

[0047] Figure 1 Schematic flow chart of the method for determining the hydraulic fracturing roof cutting and pressure relief timing of the dynamic pressure roadway provided by the present invention, as Figure 1 shown, including:

[0048] Step 100: Using the original hollow inclusion, obtain the in-situ stress of multiple fracturing boreholes in the preset mining area of the coal mine;

[0049] Step 200: Using the new hollow inclusion, collect the mining stress of the multiple fracturing boreholes again and again;

[0050] Step 300: Based on the in-situ stress and the mining stress, calculate the maximum principal stress of each fracturing borehole respectively, to determine the first included angle between the azimuth angle of the maximum principal stress and the axial direction of the roadway in the preset mining area of the coal mine, and the second included angle between the dip angle of the maximum principal stress and the vertical direction of the axial direction of the roadway;

[0051] Step 400: Obtain the preset minimum range of the first included angle and the second included angle, and determine several fracturing boreholes corresponding to the preset minimum range;

[0052] Step 500: Determine that the advanced distance of the several fracturing boreholes in the preset mining area of the coal mine is the optimal fracturing timing for fracturing operations.

[0053] In the preset mining area of a coal mine, usually in an area far from the influence of mining, multiple fracturing boreholes are set. Through the multiple fracturing boreholes, the stress of the rock formation above the roadway where the fracturing operation is carried out is measured by the stress relief method. The schematic diagram of a single fracturing borehole is as shown in Figure 2 the following figure.

[0054] First, through the original hollow inclusion, the in-situ stress of each fracturing borehole is calculated and measured. Then, a new hollow inclusion is reinstalled, and the mining stress of each fracturing borehole is calculated and measured. Further, the maximum principal stress of the fracturing borehole is obtained by comprehensively considering the in-situ stress and the mining stress.

[0055] It can be understood that since the propagation of hydraulic fracturing cracks generally occurs along the direction of the maximum principal stress of the rock mass, it is crucial to obtain the maximum principal stress of each fracturing borehole. By analyzing the parameters of the maximum principal stress, the optimal fracturing timing for implementing the fracturing borehole can be selected more accurately, ensuring that the propagation direction of the rock mass cracks can extend along the preset direction.

[0056] For the receiving points of each fracturing borehole, analyze the evolution law of the stress state at different positions in the rock formation during the process of gradually approaching the working face from a position far from the coal mining face, including the magnitudes, azimuth angles, dip angles, etc. of the three-dimensional stresses.

[0057] Furthermore, in the actual mining process, it is expected that the hydraulic fracturing cracks can be as close as possible to the vertical direction of the rock formation, that is, the vertical direction of the roadway axis, so as to achieve an ideal hydraulic fracturing roof cutting effect. However, it is often impossible to completely achieve the vertical effect. The present invention sets a preset minimum range of an included angle, that is, respectively measure whether the azimuth angle of the maximum principal stress and the included angle with the roadway axis in the preset mining area of the coal mine is as small as possible, and whether the dip angle of the maximum principal stress and the included angle with the vertical direction of the roadway axis is also as small as possible. Here, the azimuth angle and the dip angle are understood as the projections in the horizontal plane and the vertical plane respectively in the three-dimensional direction.

[0058] During the process of gradually measuring multiple fracturing boreholes, when the included angle corresponding to each fracturing borehole gradually approaches the vertical direction and then gradually moves away from the vertical direction during the measurement, it can be determined that the distance interval between these fracturing boreholes can be determined as the distance ahead of the working face. Within this distance ahead of the working face, the fracturing operation can be carried out to obtain the optimal fracturing timing.

[0059] The present invention obtains relatively accurate values such as the in-situ stress, mining stress and their variation laws through measurement, analyzes the stress evolution law of the rock formation, thereby obtaining the optimal fracturing timing of the rock formation, realizing that the cracks extend as much as possible along the vertical direction and the roadway axis, achieving the best roof cutting effect, and thus controlling the deformation of the dynamic pressure roadway.

[0060] Based on the above embodiments, before obtaining the in-situ stress of multiple fracturing boreholes in a preset mining area of a coal mine by using the original hollow inclusion, the following steps are further included:

[0061] Starting from the roof rock stratum, drill multiple fracturing boreholes obliquely downward at a preset interval distance away from the working face in the direction close to the projection of the coal pillar, and end at the top of the roadway;

[0062] Among them, the multiple fracturing boreholes are arranged at equal intervals, and the advancing direction of the multiple fracturing boreholes is consistent with the advancing direction of the working face coal mining.

[0063] It should be noted that in the present invention, by gradually arranging multiple fracturing boreholes in a preset mining area of a coal mine and analyzing them one by one, the variation law of multiple maximum principal stresses is obtained.

[0064] As Figure 3 shown, it schematically shows the planar projection effect of the positions of multiple fracturing boreholes. From the top-down projection direction, from left to right are the working face, the roadway, and the coal pillar.

[0065] The setting principle of multiple fracturing boreholes is in an area far from the mining influence, such as an area more than 300 m away from the coal mining face. Starting from the roof rock stratum, drill holes obliquely downward in the direction close to the projection of the coal pillar and end at the top of the roadway. The advancing sequence of drilling is consistent with the advancing direction of the working face coal mining; at the same time, multiple fracturing boreholes are usually arranged at equal interval distances, such as an interval of 10 m, and the inclined angle is usually between 45 degrees and 80 degrees, and is commonly set between 60 degrees and 80 degrees.

[0066] By setting the sequence of fracturing boreholes consistent with the advancing direction of the working face, the present invention can more accurately analyze and measure the in-situ stress, mining stress and their variation laws, so as to obtain the optimal fracturing timing.

[0067] Based on any of the above embodiments, obtaining the in-situ stress of multiple fracturing boreholes in a preset mining area of a coal mine by using the original hollow inclusion includes:

[0068] Install hollow inclusions in the multiple fracturing boreholes;

[0069] Relieve the stress of the multiple fracturing boreholes and withdraw the hollow inclusions;

[0070] Calculate and obtain the in-situ stress of the multiple fracturing boreholes.

[0071] Specifically, for obtaining the in-situ stress by testing, the present invention first drills boreholes, then installs hollow inclusions, then relieves the stress and withdraws the hollow inclusions, and calculates the stress at the test position, that is, the in-situ stress is obtained.

[0072] The present invention uses the stress relief method to obtain the in-situ stress of the hydraulic fracturing borehole, which has the characteristics of convenient operation, simple calculation, and intuitive data acquisition.

[0073] Based on any of the above embodiments, the step of re-collecting the mining-induced stress of the multiple hydraulic fracturing boreholes by using the new hollow inclusion includes:

[0074] Install the new hollow inclusion in the multiple hydraulic fracturing boreholes, and grout and seal the new hollow inclusion;

[0075] After the grouted and sealed hollow inclusion is coupled with the rock mass, measure and calculate the mining-induced stress of the multiple hydraulic fracturing boreholes.

[0076] Specifically, on the basis of the foregoing embodiment, the hollow inclusion is withdrawn from the hydraulic fracturing borehole, a new hollow inclusion is installed in the hydraulic fracturing borehole, and then grouted and sealed. After achieving good coupling with the rock mass, the mining-induced stress is measured by using a hollow inclusion stress gauge. The hollow inclusion stress gauge is mainly used to measure the three-dimensional stress in rocks and concrete. The installation schematic diagram is as Figure 4 shown.

[0077] The present invention further calculates the acting stress of the grouted and sealed hollow inclusion on the hydraulic fracturing borehole, which has the characteristic of accurate calculation.

[0078] Based on any of the above embodiments, the step of calculating the maximum principal stress of each hydraulic fracturing borehole based on the in-situ stress and the mining-induced stress includes:

[0079] Perform vector superposition on the in-situ stress and the mining-induced stress to obtain the maximum principal stress.

[0080] Specifically, after obtaining the in-situ stress and the mining-induced stress respectively, the present invention further obtains the absolute stress at this point, that is, the maximum principal stress, through vector superposition.

[0081] Here, by obtaining the in-situ stress of the rock formation before installing the hollow inclusion, and obtaining the mining-induced stress after installing the new hollow inclusion and grouting and sealing it, and performing vector superposition, the maximum principal stress of the hydraulic fracturing borehole is comprehensively obtained, fully considering the evolution law of the stress state at different positions in the rock formation during the whole process from far away from the coal mining face to gradually approaching the working face, including the magnitude, azimuth angle, and dip angle of the three-dimensional stress, etc.

[0082] The present invention measures the in-situ stress and the mining-induced stress respectively, fully considers the comprehensive stress of the hydraulic fracturing borehole, can obtain a relatively accurate absolute stress value, and is convenient for determining the optimal fracturing timing subsequently.

[0083] Based on any of the above embodiments, the step of obtaining the preset minimum range of the first included angle and the second included angle, and determining several hydraulic fracturing boreholes corresponding to the preset minimum range includes:

[0084] If it is determined that the first included angle corresponding to any one of the fracturing boreholes is close to the axial direction of the roadway, and the corresponding second included angle is close to the direction perpendicular to the axial direction of the roadway, and both the first included angle and the second included angle are within the preset minimum range, then determine the position corresponding to any one of the fracturing boreholes as the starting value of the advanced working face distance;

[0085] If it is determined that the first included angle corresponding to any other fracturing borehole is far from the axial direction of the roadway, and the corresponding second included angle is far from the direction perpendicular to the axial direction of the roadway, and both the first included angle and the second included angle are within the preset minimum range, then determine the position corresponding to any other fracturing borehole as the ending value of the advanced working face distance.

[0086] Specifically, according to the stress state evolution law of the present invention, the first included angle between the azimuth angle of the maximum principal stress and the axial direction of the roadway, and the second included angle between the dip angle of the maximum principal stress and the direction perpendicular to the axial direction of the roadway are judged, and the above two included angles are simultaneously constrained, so that the position where the maximum principal stress should be as close as possible to the vertical direction is an ideal fracturing borehole, and it is necessary to accurately calculate the relative position with the working face, and determine a relatively effective distance range as the preset minimum range corresponding to the advanced working face distance.

[0087] Such as Figure 5 shown, when the positions of the fracturing boreholes are advanced one by one, the first included angle and the second included angle of each fracturing borehole are calculated in turn. When the first included angle corresponding to a certain fracturing borehole begins to approach the axial direction of the roadway, and the second included angle begins to approach the direction perpendicular to the axial direction of the roadway, and both are within the preset minimum range, then it can be determined that the position corresponding to this point is the starting value of the advanced working face distance to be determined, as shown in Figure 5 point A shown in

[0088] Correspondingly, as the test continues, when the first included angle corresponding to a certain fracturing borehole begins to deviate from the axial direction of the roadway, and the second included angle begins to deviate from the direction perpendicular to the axial direction of the roadway, and still within the preset minimum range, then it can be determined that the position corresponding to this point is the ending value of the advanced working face distance to be determined, as shown in Figure 5 point B shown in

[0089] Take the distance between point A and point B as the advanced working face distance, that is, corresponding to the optimal fracturing timing.

[0090] Here, during the fracturing process of the present invention, through the actual measurement of the fracture propagation law, the relationship between the fracture propagation path and the maximum principal stress evolution can be verified, and it effectively overcomes the limitation that the expansion of hydraulic fracturing fractures is affected by many factors such as the stress environment, primary fractures, rock formation structure, and fracturing parameters, and its propagation law cannot be accurately obtained by theoretical calculation or numerical simulation calculation.

[0091] Based on any of the above embodiments, the plurality of fracturing boreholes is at least 2.

[0092] Optionally, the installation quantity of the fracturing boreholes involved in the present invention can be determined according to the actual vertical height of the fracturing boreholes, and is at least not less than 2 for mutual verification. In actual layout, usually multiple test points need to be set within a certain distance range to obtain more accurate measurement data.

[0093] The system for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway provided by the present invention will be described below. The system for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway described below can be mutually corresponding and referred to with the method for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway described above.

[0094] Figure 6 is a schematic structural diagram of the system for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway provided by the present invention, as Figure 6 shown, including: an acquisition module 61, a collection module 62, a calculation module 63, a processing module 64, and a determination module 65, wherein:

[0095] The acquisition module 61 is used to obtain the in-situ stress of a plurality of fracturing boreholes in a preset mining area of a coal mine by using an original hollow inclusion; the collection module 62 is used to repeatedly collect the mining-induced stress of the plurality of fracturing boreholes by using a new hollow inclusion; the calculation module 63 is used to calculate the maximum principal stress of each fracturing borehole based on the in-situ stress and the mining-induced stress, so as to determine the first included angle between the azimuth angle of the maximum principal stress and the axial direction of the roadway in the preset mining area of the coal mine, and the second included angle between the dip angle of the maximum principal stress and the direction perpendicular to the axial direction of the roadway; the processing module 64 is used to obtain the preset minimum range of the first included angle and the second included angle, and determine a plurality of fracturing boreholes corresponding to the preset minimum range; the determination module 65 is used to determine that the distance of the plurality of fracturing boreholes in front of the working face in the preset mining area of the coal mine is the optimal fracturing timing for fracturing operations.

[0096] The present invention obtains relatively accurate values such as in-situ stress, mining-induced stress and their variation laws through measurement, analyzes the stress evolution law of the rock formation, thereby obtains the optimal fracturing timing of the rock formation, realizes that the fractures expand as much as possible along the vertical direction and the axial direction of the roadway, achieves the best roof cutting effect, and thus controls the deformation of the dynamic pressure roadway.

[0097] Figure 7 illustrates a schematic diagram of the physical structure of an electronic device, as Figure 7 shown, the electronic device may include: a processor 710, a communications interface 720, a memory 730, and a communication bus 740. Among them, the processor 710, the communication interface 720, and the memory 730 communicate with each other through the communication bus 740. The processor 710 may call the logical instructions in the memory 730 to execute a method for determining the hydraulic fracturing roof cutting and pressure relief timing in a dynamic pressure roadway. The method includes: using an original hollow inclusion to obtain the in-situ stress of multiple fracturing boreholes in a preset mining area of a coal mine; using a new hollow inclusion to repeatedly collect the mining stress of the multiple fracturing boreholes; based on the in-situ stress and the mining stress, calculating the maximum principal stress of each fracturing borehole respectively to determine the first included angle between the azimuth angle of the maximum principal stress and the axial direction of the roadway in the preset mining area of the coal mine, and the second included angle between the dip angle of the maximum principal stress and the direction perpendicular to the axial direction of the roadway; obtaining the preset minimum range of the first included angle and the second included angle, and determining several fracturing boreholes corresponding to the preset minimum range; determining that the distance of the several fracturing boreholes from the working face in the preset mining area of the coal mine is the optimal fracturing timing for fracturing operations.

[0098] In addition, when the logical instructions in the above-mentioned memory 730 are implemented in the form of software functional units and sold or used as an independent product, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0099] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the method for determining the hydraulic fracturing roof cutting and pressure relief timing provided by the above-mentioned various methods. The method includes: using an original hollow inclusion to obtain the in-situ stress of multiple fracturing boreholes in a preset mining area of a coal mine; using a new hollow inclusion to repeatedly collect the mining stress of the multiple fracturing boreholes; based on the in-situ stress and the mining stress, calculating the maximum principal stress of each fracturing borehole respectively to determine the first angle between the azimuth angle of the maximum principal stress and the axial direction of the roadway in the preset mining area of the coal mine, and the second angle between the dip angle of the maximum principal stress and the direction perpendicular to the axial direction of the roadway; obtaining the preset minimum range of the first angle and the second angle, and determining several fracturing boreholes corresponding to the preset minimum range; determining the distance of the several fracturing boreholes in front of the working face in the preset mining area of the coal mine as the optimal fracturing timing for fracturing operations.

[0100] In another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it realizes the method for determining the hydraulic fracturing roof cutting and pressure relief timing provided by the above-mentioned various methods. The method includes: using an original hollow inclusion to obtain the in-situ stress of multiple fracturing boreholes in a preset mining area of a coal mine; using a new hollow inclusion to repeatedly collect the mining stress of the multiple fracturing boreholes; based on the in-situ stress and the mining stress, calculating the maximum principal stress of each fracturing borehole respectively to determine the first angle between the azimuth angle of the maximum principal stress and the axial direction of the roadway in the preset mining area of the coal mine, and the second angle between the dip angle of the maximum principal stress and the direction perpendicular to the axial direction of the roadway; obtaining the preset minimum range of the first angle and the second angle, and determining several fracturing boreholes corresponding to the preset minimum range; determining the distance of the several fracturing boreholes in front of the working face in the preset mining area of the coal mine as the optimal fracturing timing for fracturing operations.

[0101] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0102] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the timing of hydraulic fracturing roof cutting and pressure relief in dynamic pressure roadway, characterized in that, Including: Using the original hollow inclusion, obtaining the in-situ stress of multiple fracturing boreholes in the preset mining area of the coal mine; Using a new hollow inclusion to repeatedly collect the mining stress of the multiple fracturing boreholes; Based on the in-situ stress and the mining stress, calculating the maximum principal stress of each fracturing borehole respectively to determine the first included angle between the azimuth angle of the maximum principal stress and the axial direction of the roadway in the preset mining area of the coal mine, and the second included angle between the dip angle of the maximum principal stress and the direction perpendicular to the axial direction of the roadway; Obtaining the preset minimum range of the first included angle and the second included angle, and determining several fracturing boreholes corresponding to the preset minimum range; Determining that the advanced working face distance of the several fracturing boreholes in the preset mining area of the coal mine is the optimal fracturing timing for fracturing operations; Before obtaining the in-situ stress of multiple fracturing boreholes in the preset mining area of the coal mine by using the original hollow inclusion, it further includes: Starting from the roof rock stratum, drilling multiple fracturing boreholes obliquely downward in the direction close to the projection direction of the coal pillar and at a preset interval distance away from the working face, and ending at the top of the roadway; Among them, the multiple fracturing boreholes are arranged at equal intervals, and the advancing direction of the multiple fracturing boreholes is consistent with the advancing direction of the working face coal mining; The obtaining the preset minimum range of the first included angle and the second included angle, and determining several fracturing boreholes corresponding to the preset minimum range includes: If it is determined that the first included angle corresponding to any fracturing borehole is close to the axial direction of the roadway, and the corresponding second included angle is close to the direction perpendicular to the axial direction of the roadway, and both the first included angle and the second included angle are within the preset minimum range, then determining the position corresponding to the any fracturing borehole as the starting value of the advanced working face distance; If it is determined that the first included angle corresponding to any other fracturing borehole is far from the axial direction of the roadway, and the corresponding second included angle is far from the direction perpendicular to the axial direction of the roadway, and both the first included angle and the second included angle are within the preset minimum range, then determining the position corresponding to the any other fracturing borehole as the ending value of the advanced working face distance.

2. The method for determining the hydraulic fracturing roof cutting and pressure relief timing in a dynamic pressure roadway according to claim 1, wherein The obtaining the in-situ stress of multiple fracturing boreholes in the preset mining area of the coal mine by using the original hollow inclusion includes: Installing hollow inclusions in the multiple fracturing boreholes; Releasing the stress of the multiple fracturing boreholes and withdrawing the hollow inclusions; Calculating and obtaining the in-situ stress of the multiple fracturing boreholes.

3. The method for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway according to claim 1, wherein The using a new hollow inclusion to repeatedly collect the mining stress of the multiple fracturing boreholes includes: Installing the new hollow inclusion in the multiple fracturing boreholes and grouting and encapsulating the new hollow inclusion; After the grouted and encapsulated hollow inclusion is coupled with the rock mass, measuring and calculating to obtain the mining stress of the multiple fracturing boreholes.

4. The method for determining the hydraulic fracturing roof cutting and pressure relief timing in a dynamic pressure roadway according to claim 1, characterized in that The calculating the maximum principal stress of each fracturing borehole respectively based on the in-situ stress and the mining stress includes: Performing vector superposition on the in-situ stress and the mining stress to obtain the maximum principal stress.

5. The method for determining the hydraulic fracturing roof cutting and pressure relief timing of a dynamic pressure roadway according to any one of claims 1 to 4, characterized in that The multiple fracturing boreholes are at least 2.

6. A system for determining the timing of hydraulic fracturing and roof pressure relief in a dynamic pressure roadway, characterized in that, Including: An acquisition module for obtaining the in-situ stress of multiple fracturing boreholes in the preset mining area of the coal mine by using the original hollow inclusion; A collection module, configured to re-collect the mining-induced stress of the multiple fracturing boreholes multiple times by using a new hollow inclusion. A calculation module, configured to calculate the maximum principal stress of each fracturing borehole based on the virgin rock stress and the mining-induced stress, so as to determine a first included angle between the azimuth angle of the maximum principal stress and the axial direction of the roadway in the preset mining area of the coal mine, and a second included angle between the dip angle of the maximum principal stress and the direction perpendicular to the axial direction of the roadway. A processing module, configured to obtain a preset minimum range of the first included angle and the second included angle, and determine several fracturing boreholes corresponding to the preset minimum range. A determination module, configured to determine that the advanced working face distance of the several fracturing boreholes in the preset mining area of the coal mine is the optimal fracturing timing for fracturing operations. Before obtaining the virgin rock stress of multiple fracturing boreholes in the preset mining area of the coal mine by using the original hollow inclusion, the obtaining module is further configured to: Starting from the roof rock stratum, drill a plurality of fracturing boreholes downward obliquely in the direction close to the projection direction of the coal pillar and at a preset interval distance away from the working face, and stop at the top of the roadway. Wherein, the plurality of fracturing boreholes are arranged at equal intervals, and the advancing directions of the plurality of fracturing boreholes are consistent with the advancing direction of the working face mining. The processing module is specifically configured to: If it is determined that the first included angle corresponding to any one fracturing borehole is close to the axial direction of the roadway, and the corresponding second included angle is close to the direction perpendicular to the axial direction of the roadway, and both the first included angle and the second included angle are within the preset minimum range, then determine that the position corresponding to the any one fracturing borehole is the starting value of the advanced working face distance. If it is determined that the first included angle corresponding to any other fracturing borehole is far from the axial direction of the roadway, and the corresponding second included angle is far from the direction perpendicular to the axial direction of the roadway, and both the first included angle and the second included angle are within the preset minimum range, then determine that the position corresponding to the any other fracturing borehole is the ending value of the advanced working face distance.

7. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the method for determining the hydraulic fracturing roof cutting and pressure relief timing of the dynamic pressure roadway according to any one of claims 1 to 5.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method for determining the hydraulic fracturing roof cutting and pressure relief timing of the dynamic pressure roadway according to any one of claims 1 to 5.

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