Coal seam floor hazard prevention and control method based on integral movement of drilling machine

Abstract

The invention provides a coal seam floor hazard prevention and control method based on drilling machine integral movement, and relates to the technical field of coal mine hazard prevention and control. The method comprises the steps that coal mine information is analyzed, an engineering range and a construction scheme are determined, the construction scheme comprises drilling design, and the drilling design comprises a main hole and a plurality of corresponding pinniform branch holes; drilling construction is conducted on the main hole through a drilling machine; the drilling machine is moved through the translation device, and the multiple pinniform branch holes are subjected to cross drilling construction; and the multiple pinniform branch holes are grouted through the main hole so as to isolate the water guide channel on the coal seam bottom plate. By means of the translation device, the drilling machine can move in a limited area, so that a plurality of pinniform branch holes can be constructed in a crossed mode at the same time in the same well field with the limited area, the construction period is greatly shortened, meanwhile, the invalid stop time caused by drilling grouting is shortened, and the efficiency of advanced prevention and treatment of high-pressure-bearing water disasters of a coal seam floor is improved.

Description

Technical Field

[0001] The present application relates to the technical field of coal mine hazard prevention and control, and in particular to a method for preventing and controlling coal seam floor hazards based on overall movement of a drilling rig. Background Art

[0002] As the mining of coal resources in the upper part of coal mines gradually becomes exhausted, the mining of coal resources in the lower part of coal mines often faces the threat of deep mining and high pressure water hazards. There are many mines in the country that are threatened by high pressure karst water hazards in the bottom plate. The high pressure karst water hazard accidents in the bottom plate are extremely harmful. Once the water bursts, it will bring disaster to the coal mine. Therefore, the advanced prevention and control of high pressure water hazards in the coal seam bottom plate has become a hot issue at present.

[0003] In the related art, the water-conducting channels developed on the upper part of the coal mine floor are isolated by drilling the main hole and each feather-shaped branch hole one by one, and injecting grout into the main hole and the feather-shaped branch holes, thereby achieving advanced prevention and control of high-pressure water hazards in the coal seam floor.

[0004] However, the method of drilling the main hole and each feather-shaped branch hole one by one and injecting grout into the main hole and the feather-shaped branch holes has the problems of long construction period and low efficiency.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present application, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0006] The present application provides a method for preventing and controlling coal seam floor hazards based on the overall movement of a drilling rig, which at least to a certain extent solves the problem of long construction period and low efficiency of the scheme for advanced prevention and control of high-pressure water hazards in coal seam floors.

[0007] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0008] According to one aspect of the present application, a method for preventing and controlling coal seam floor hazards based on the overall movement of a drilling rig is provided, and a translation device assisting the overall movement of the drilling rig includes: a translation base and a hydraulic cylinder support, and the hydraulic cylinder support is used to push and pull the drilling rig to move on the translation base. The method includes: analyzing coal mine information, determining the scope of the project and the construction plan, the construction plan includes a drilling design, and the drilling design includes a main hole and corresponding multiple feather-shaped branch holes; drilling the main hole by the drilling rig; moving the drilling rig by the translation device to cross-drill the multiple feather-shaped branch holes; grouting into the multiple feather-shaped branch holes through the main hole to isolate the water guide channel on the coal seam floor.

[0009] In one embodiment of the present application, it also includes: performing one or more tests including cuttings logging, drilling logging, hydrological observation, mud property testing, and gamma logging during the drilling construction of the main hole and the multiple feather-shaped branch holes, and adjusting the drilling construction plan based on the test results of the one or more tests.

[0010] In one embodiment of the present application, the process of cuttings logging includes: collecting cuttings at a preset position according to the logging interval and the delay time, wherein the delay time is the time required for the cuttings to return from the bottom of the well to the wellhead; cleaning the collected cuttings according to the lithology of the cuttings; and drying the cleaned cuttings.

[0011] In one embodiment of the present application, the late arrival time is calculated according to the following formula:

[0012]

[0013] Among them, t is the cuttings delay time; V is the annular space volume between the wellbore and the drill pipe; Q is the displacement of the drilling pump; D is the well diameter or drill bit diameter; d is the outer diameter of the drill pipe; H is the well depth.

[0014] In one embodiment of the present application, the calculation method of the late time is: select a physical object whose size and density are within a preset difference with the cuttings, and put the physical object into the drill pipe, record the pump start time after the physical object is put in and the return time of the physical object, calculate the time difference between the pump start time and the return time, and obtain the cycle period; calculate the late time according to the cycle period and using the following formula:

[0015] t=t 1 -t 0

[0016]

[0017] Where, t is the late time; t 1 is the cycle period; t 0 V is the time it takes for the object to descend along the drill pipe to the bottom of the well; 1 V is the internal volume of the drill pipe; 2 is the internal volume of the drill collar; d 1 is the inner diameter of the drill pipe; d 2 is the inner diameter of the drill collar; L 1 is the length of the drill pipe; L 2 is the length of the drill collar; G is the mud displacement.

[0018] In one embodiment of the present application, the drilling fluid logging includes: measuring and recording the routine performance of the drilling fluid once at a first preset time interval, measuring and recording the full performance of the drilling fluid once at a second preset time interval, and continuously measuring and recording the routine performance of the drilling fluid when drilling into a coal seam hole section or finding abnormal gas display.

[0019] In one embodiment of the present application, the grouting into the plurality of feather-like branch holes through the main hole includes: flushing the plurality of feather-like branch holes; conducting a water pressure test to measure the water permeability of a unit receiving layer; determining the density of the slurry according to the water permeability and preparing the slurry; and grouting into the plurality of feather-like branch holes through three stages of normal pressure grouting, pressurized grouting and high pressure grouting.

[0020] In one embodiment of the present application, the water permeability can be calculated by the following formula:

[0021]

[0022] Among them, q is the water permeability; U is the pressure flow rate in the water pressure test; P is the total pressure acting in the test pressure section in the water pressure test; L is the length of the test pressure section.

[0023] In one embodiment of the present application, it also includes: collecting geological, hydrogeological, geophysical, and underground mining data of the coal mine; analyzing the data and the main hole, using the main hole as a ground gas hole, and determining the final hole target position of the ground gas hole; opening a hole in the underground tunnel of the coal mine and drilling to the final hole target position; continuing to drill to the final hole target position on the basis of the main hole, and when drilling to a preset distance before the final hole target position, installing a target guidance system on the drilling rig, and lowering a signal receiving probe into the underground borehole, adjusting the ground drilling trajectory according to the magnetic guidance data to drill the remaining hole section, so that the hole section drilled from the underground tunnel is connected to the main hole.

[0024] In one embodiment of the present application, after drilling is continued towards the final hole target position based on the main hole, when the deviation between the final hole position of the main hole and the final hole target position exceeds the inclination deviation threshold, a new borehole is reconstructed in the underground tunnel according to the final hole position of the main hole for docking.

[0025] The technical solution provided by the embodiments of the present application includes at least the following beneficial effects:

[0026] The technical solution provided in the embodiment of the present application utilizes a translation device to enable the drilling rig to move within a limited area, so that multiple feather-shaped branch holes can be cross-constructed simultaneously in the same well site with a limited area. Compared with the method of drilling the main hole and each feather-shaped branch hole one by one and grouting into the main hole and the feather-shaped branch holes, the construction period is greatly shortened, and the ineffective waiting time caused by drilling and grouting is reduced, thereby improving the efficiency of advanced prevention and control of high-pressure water hazards in the coal seam floor.

[0027] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A flow chart showing a method for preventing and controlling coal seam floor hazards based on overall movement of a drilling rig in one embodiment of the present application;

[0030] Figure 2 A flow chart showing coal mine gas control using a main hole for controlling high-pressure water hazards on a coal floor in another embodiment of the present application is shown. DETAILED DESCRIPTION

[0031] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0032] In addition, the accompanying drawings are only schematic illustrations of the present application and are not necessarily drawn to scale. The same reference numerals in the drawings represent the same or similar parts, and thus their repeated descriptions will be omitted. It should be noted that the concepts of "first", "second", etc. mentioned in the present application are only used to distinguish different preset durations, etc.

[0033] The promotion and application of horizontal directional drilling technology in coal mine water prevention and control is becoming more and more common. Multiple boreholes are often arranged in the same well site. However, due to the limitations of site terrain and other conditions, each main hole and the corresponding multiple feather-shaped branch holes need to be drilled separately, resulting in low construction period and efficiency.

[0034] When the inventor studied how to improve construction efficiency, he found that when multiple drilling rigs cannot be placed for construction at the same time due to site terrain and other conditions, a translation device can be configured and used to move the drilling rig to achieve simultaneous cross-construction of multiple boreholes in the same well site with a limited area, thereby shortening the construction period, reducing the ineffective waiting time caused by drilling and grouting, and rationally optimizing resource allocation.

[0035] A method for preventing and controlling coal seam floor hazards based on overall movement of a drilling rig in one embodiment of the present application may include the following S101 to S104.

[0036] S101, analyzing coal mine information, determining the scope of the project and the construction plan, the construction plan including drilling design, the drilling design including the main hole and corresponding multiple feather-shaped branch holes.

[0037] In one embodiment, the drilling design includes the position of the main hole, the position of each feather-shaped branch hole under the main hole, and the direction of the drilling.

[0038] In one embodiment, the drilling design also includes technical requirements for drilling during drilling. The embodiments of the present application do not limit what the technical requirements specifically include. For example, the technical requirements may include the following content.

[0039] 1. During the drilling process, the construction shall be strictly carried out according to the design parameters. At the same time, actual drilling monitoring shall be carried out according to the design requirements, and the construction parameters and measures shall be adjusted in time.

[0040] 2. The wellbore azimuth is strictly controlled in the deflection section, and the azimuth is controlled within the first angle range of the designed azimuth. The closing azimuth of the deflection section shall not exceed the first angle of the designed wellbore. The embodiments of the present application do not limit the specific range of the first angle range and the first angle. For example, the first angle range is (-2, 2) degrees, and the first angle is 1.5 degrees.

[0041] 3. The directional layer-following trajectory of each feather-shaped branch hole group should be constructed in the set gray layer. The layer position should be strictly controlled during the construction of all drilling groups, and the layer (depth) rate shall not be less than the first threshold percentage (the specific value of the first threshold percentage is not limited in the embodiments of the present application. For example, 80%); the actual trajectory of the horizontal branch hole shall not deviate from the designed trajectory by more than the threshold trajectory deviation (the specific value of the threshold trajectory deviation is not limited in the embodiments of the present application. For example, 2 meters), and the hole section exceeding the threshold trajectory deviation shall not exceed the second threshold percentage of the whole hole section (the specific value of the second threshold percentage is not limited in the embodiments of the present application. For example, 15%).

[0042] 4. Logging: For rock cuttings logging, sand samples are not collected for the Quaternary system, and the bedrock interface needs to be determined. One bag of sand samples is collected at a certain interval (for example, 1 meter) in the bedrock section until drilling is completed, identification is done, stratigraphic profiles are established, rock cuttings logging tables are sorted and summarized on site, and preliminary judgments and divisions of the strata are made. During the drilling process, a gamma probe is added to the drilling instrument to obtain the formation gamma parameters at any time.

[0043] 5. Before each drilling, the drilling tool must be measured and the well depth must be calibrated. The well depth error must not exceed the threshold well depth error (the embodiment of the present application does not limit the specific value of the threshold well depth error. For example, 0.5 meters).

[0044] 6. Simple hydrological observation: The construction site is equipped with hydrogeological engineers to carry out hydrological observation and analysis. The full performance of the mud is measured every second preset time (the specific value of the second preset time is not limited in the embodiments of this application, for example, the first preset time is 8 hours), and the general mud properties (for example, density, viscosity) are measured every first preset time (the specific value of the first preset time is not limited in the embodiments of this application, for example, the first preset time is 2 hours); the water level (including the liquid level in the mud pool and the liquid level in the well) is measured once after each drilling and before drilling; the drilling fluid consumption adopts an automatic monitoring system, and the system is set to record once every preset interval (for example, 30 minutes), and the observation is intensified when necessary. If a large amount of water leakage, drill drop, buried drill, water gushing, etc. are found during the drilling process, the current drilling depth, layer and flushing fluid consumption should be recorded in detail.

[0045] 7. Use thin mud or solid-free mud for drilling.

[0046] 8. Each drilling rig at the construction site is equipped with a hydrogeological engineer who can adjust the drilling trajectory at any time according to the conditions in the hole.

[0047] In one embodiment, the grouting design includes the technical requirements for grouting during grouting. The embodiments of the present application do not limit what the technical requirements specifically include. For example, the technical requirements for grouting may include the following.

[0048] 1. Grouting target layer: determine the grouting target layer of each feather branch hole; for example, the grouting target layer of a feather branch hole is Limestone or its top sandstone.

[0049] 2. Grouting principles and grouting stopping methods: Follow the principle of first thin and then thick, and then re-inject thick slurry, stop grouting at the hole mouth, and grout horizontal branch holes in sections or forward grouting. Continuous grouting is combined with intermittent grouting, and the intermittent grouting time is not less than the preset grouting interval (for example, 12 hours).

[0050] 3. Grouting material: Select the grouting material. For example, 32.5 slag silicate cement is generally used; in special cases, medium and fine sand is selected as aggregate.

[0051] 4. Grouting parameters:

[0052] 4.1. Slurry specific gravity and proportion. For example, the slurry specific gravity is 1.2-1.5; for example, the water-cement ratio is 3.0:1, the specific gravity is 1.20; the water-cement ratio is 2.0:1, the specific gravity is 1.29; the water-cement ratio is 1.4:1, the specific gravity is 1.39; the water-cement ratio is 1.0:1, the specific gravity is 1.51.

[0053] 4.2. Pump capacity. For example, 3.6~60m 3 / h (cubic meters / hour).

[0054] 4.3. Final grouting pressure. For example, the final grouting pressure shall be no less than 1.5 times the hydrostatic pressure of the Ordovician limestone aquifer at the maximum vertical depth of the horizontal section of the borehole.

[0055] 5. Single hole grouting end standard: grouting final pressure reaches the design pressure; or, the final grouting pump volume is 3.6m 3 / h and maintain for more than 30 minutes; or, the unit water absorption rate of the drilling hole in the grouting section is not more than 0.01L / min (liter / minute).

[0056] In one embodiment, the construction plan also includes a specific construction plan for drilling holes and a specific construction plan for grouting into a plurality of feather-shaped branch holes.

[0057] S102, drilling the main hole by using a drilling rig.

[0058] The process of drilling the main hole by means of a drilling rig may include: drilling a straight hole section and lowering pipes to protect the wall; drilling an inclined hole section (directional hole section) and lowering pipes to protect the wall.

[0059] S103, moving the drilling rig by means of a translation device to perform cross drilling of a plurality of feather-shaped branch holes.

[0060] According to the construction design, for the feather-shaped branch holes that can be cross-constructed, cross-construction is carried out by moving the drilling rig with a translation device.

[0061] The translation device includes a translation base and a hydraulic cylinder support, and the hydraulic cylinder support is used to push and pull the drilling rig to move on the translation base.

[0062] In one embodiment, during the drilling construction of the main hole and multiple feather-shaped branch holes, one or more tests including cuttings logging, drilling logging, hydrological observation, mud property testing, and gamma logging are performed, and the drilling construction plan is adjusted based on the test results of one or more tests.

[0063] In one embodiment, the process of cuttings logging includes: collecting cuttings at a preset position according to the logging interval and the delay time, where the delay time is the time required for the cuttings to return from the bottom of the well to the wellhead; cleaning the collected cuttings according to the lithology of the cuttings; and drying the cleaned cuttings.

[0064] In one embodiment, the late time is calculated according to the following formula 1:

[0065]

[0066] Among them, t is the cuttings delay time; V is the annular space volume between the wellbore and the drill pipe; Q is the displacement of the drilling pump; D is the well diameter or drill bit diameter; d is the outer diameter of the drill pipe; H is the well depth.

[0067] In another embodiment, the late time is calculated by selecting a physical object whose size and density are within a preset difference with the cuttings, and inserting the physical object into the drill pipe, recording the pump start time after inserting the physical object and the return time of the physical object, and calculating the time difference between the pump start time and the return time to obtain the cycle period;

[0068] Calculate the late time based on the cycle period using the following formula 2 and formula 3:

[0069] t=t 1 -t 0 (2)

[0070]

[0071] Where, t is the late time; t 1 is the cycle period; t 0 V is the time it takes for the object to descend along the drill pipe to the bottom of the well; 1 V is the internal volume of the drill pipe; 2 is the internal volume of the drill collar; d 1 is the inner diameter of the drill pipe; d 2 is the inner diameter of the drill collar; L 1 is the length of the drill pipe; L 2 is the length of the drill collar; G is the mud displacement.

[0072] In another embodiment, the late time can be measured by the marker layer method. When the coal seam is exposed, the drilling time will suddenly increase, the drilling pressure will change dramatically, and the time when the marker layer is observed on the vibrating screen is the late time.

[0073] It should be noted that the late time increases with the increase of well depth. Generally, the late time is measured once at a certain interval as the late time within the interval.

[0074] In one embodiment, drilling fluid logging includes: measuring and recording the routine performance of the drilling fluid once at a first preset time interval, measuring and recording the full performance of the drilling fluid once at a second preset time interval, and continuously measuring and recording the routine performance of the drilling fluid when drilling into a coal seam hole section or discovering abnormal gas display.

[0075] In one embodiment, the interval requirement of logging while drilling is: one point is recorded at a certain distance (for example, 1 m) from the bedrock section to the completion of the well.

[0076] When logging during drilling, it is necessary to record the sudden change points during drilling at any time in order to timely discover coal seams, target limestone layers, etc., accurately determine the depth and thickness of the formations, and try to keep the drilling parameters relatively stable in order to improve the effectiveness of the drilling parameters in reflecting the lithology of the formations and record the non-geological factors that cause the drill to get stuck.

[0077] In addition, the drilling tool length and hole depth need to be checked frequently. The hole depth must be checked after each branch hole is drilled. The hole depth error must not exceed the error threshold percentage of the total length of the branch hole (for example, 1.5%). The number of missed drilling points in the whole hole must not exceed the total missed threshold percentage (for example, 0.5%), and the drilling time points of the target layer section must not be missed.

[0078] The technical requirements for hydrological observations can be as follows.

[0079] 1. During the whole hole drilling process, simple hydrological observation records should be made strictly in accordance with the drilling requirements.

[0080] 2. Measure the water level (fluid level in the wellbore) after each start of drilling and before each lowering of the drill; record the drilling fluid consumption (liquid level in the mud pool) every certain period of drilling (for example, 1 hour). When drilling into leaks, caves, large fissures, and severely collapsed layers in the fractured zone, the start and end depth records must be detailed and clear.

[0081] 3. Consumption observation: observe once at regular intervals (for example, 1 hour). For trips less than 1 hour (taking 1 hour as an example), observe once for each trip. When drilling fluid leakage is found, observe once every 10 to 30 minutes. When all the drilling fluid is lost, the pump should be turned on to measure the maximum leakage.

[0082] 4. Water level observation: Observe the water level once after each drilling and before each drilling, and measure the water temperature in case of abnormal conditions.

[0083] 5. The drilling consumption and water level observation times should reach 100% of the required times.

[0084] In some embodiments, measurement while drilling may also be performed during the drilling construction process.

[0085] Measurement while drilling technology: Directional drilling is carried out using wireless inclinometers in the inclination section and horizontal section, and the wellbore trajectory is accurately controlled, and geological guidance is carried out in conjunction with drilling logging, cuttings logging and other methods.

[0086] The main purpose of measurement while drilling:

[0087] 1. In the vertical well section, real-time well inclination monitoring is carried out and the screw is lowered for inclination correction control when necessary.

[0088] 2. In the deflection section, through directional control, the actual drilling depth trajectory is drilled according to the design, and a smooth trajectory is drilled to avoid doglegs. This is beneficial to underground safety.

[0089] 3. In the horizontal section, adjust the well inclination according to the occurrence of the target layer to ensure effective drilling in the target layer.

[0090] 4. Purpose of geological guidance: Combined with logging, gamma while drilling and other means, accurately determine the formation changes. The main task before entering the window is to provide the target layer change of the window entry point, provide target data for orientation, adjust the next step trajectory in time, and finally reach the appropriate well inclination angle to drill into the target layer. The purpose of the horizontal section is to calculate the inclination and structural conditions of the target layer in real time, provide well inclination instructions for orientation, and control the well inclination change to keep drilling in the target layer.

[0091] Measurement while drilling: Gamma measurement data while drilling plays an important guiding role in constructing horizontal sections. Generally, the distance between the drill bit and the target limestone layer is judged based on the gamma amplitude of the drilled stratum. When the gamma amplitude is low, the lithology is limestone. When the gamma amplitude is high, the drill bit is close to the coal (mudstone) layer. Therefore, based on the gamma measurement data while drilling, the drilling status of the drill bit in the horizontal section can be judged. When the target layer is about to be drilled out, the directional data can be corrected, the wellbore trajectory can be adjusted in time, and the drill bit can be kept running in the target layer.

[0092] Borehole trajectory control measures: The equipment is installed and debugged strictly according to the drilling rig standards, especially the deviation of the crown block, turntable and hole mouth is less than the first preset value (for example, 10mm), and the test run is carried out according to the regulations. The next construction step can be carried out only after the requirements are met. Strengthen the inspection and calibration of MWD (Measurement While Drilling) equipment to ensure that the equipment is sensitive and accurate. When the mud is completely lost and cannot be returned, the MWD equipment will stop working. Drilling should not continue at this time. When drilling is required, the footage should be controlled not to exceed the second preset value (for example, 5m). In order to ensure that the MWD drilling monitoring equipment receives good signals, the solid content of rock cuttings and other solids in the mud should be controlled (less than 0.3%).

[0093] S104, grouting is performed through the main hole into multiple feather-shaped branch holes to isolate the water-conducting channels on the coal seam floor.

[0094] In one embodiment, grouting into a plurality of feather-shaped branch holes through a main hole may include: flushing the plurality of feather-shaped branch holes; conducting a water pressure test to determine the water permeability of a unit receiving layer; determining the density of the slurry according to the water permeability and preparing the slurry; and grouting into the plurality of feather-shaped branch holes through three stages: normal pressure grouting, pressurized grouting, and high pressure grouting.

[0095] The purpose of flushing the multiple feather-shaped branch holes is to remove the mud skin on the hole wall through the circulating mud, so as to achieve the purpose of flushing the cracks in the hole.

[0096] The operation process of flushing multiple feather-shaped branch holes is to circulate the drilling fluid after drilling to the final hole. During the circulation process, the drill tool needs to be moved up and down to ensure the safety of the drill tool. The remaining rock debris in the hole is brought up through circulation until there is no rock debris in the drilling fluid returned to the hole. Then the borehole is replaced with slurry, the mud in the hole is replaced with clean water, and the clean water is circulated (the circulation time should be no less than 1 hour). The drill tool must be moved frequently during the circulation of clean water, and the safety of the hole is ensured by lifting the drill tool during the circulation of clean water.

[0097] The purpose of the water pressure test with clean water before grouting is to dredge the grouting pipeline and the rock cracks in the hole, measure the water permeability of the unit receiving layer, and re-determine the amount of leakage through the change, providing a solid basis for grouting. The results of the water pressure test are expressed as the water permeability q.

[0098] In one embodiment, the water permeability can be calculated by the following formula 4:

[0099]

[0100] Among them, q is the water permeability; U is the pressure flow rate in the water pressure test; P is the total pressure acting in the test pressure section in the water pressure test; L is the length of the test pressure section.

[0101] Normal pressure grouting stage: At the beginning of grouting, there is only lime water in the cracks. After the slurry is injected, since the density of the slurry is greater than the density of the lime water in the cracks, the slurry can enter the cracks by its own weight and play the role of replacing the lime water.

[0102] Pressurized grouting stage: The grouting pressure in this stage is generally 2 to 3 MPa (megapascals). Grouting is carried out in still water with the pressure at the hole gradually increasing. The purpose is to block small crack channels. Under the action of pressure, the slurry can further diffuse horizontally and vertically, thereby increasing the control range of drilling grouting and making the originally isolated cement firmly connected into a whole.

[0103] High-pressure grouting stage: The later high-pressure grouting is to consolidate the effect of the previous grouting. Due to the high head pressure of Ordnance Gray Water, the head pressure is generally around 6-8Mpa, and the solidification compressive strength of pressurized grouting cement is less than the head pressure. Therefore, in the later stage of pressurized grouting, the cement injection volume should be adjusted and the grouting pressure should be increased. According to the requirements, the bottom pressure of the grouting hole in the high-pressure grouting stage is 1.5-2 times the hydrostatic pressure of Ordnance Gray Water. When the pressure stabilizes, stop grouting and sweep the hole.

[0104] In one embodiment, after grouting is completed, each feather-shaped branch hole is sealed. The sealing cement slurry should be returned from the bottom of the hole to the next branch inclination point, and a high-grade cement is used as a cement plug at the inclination point.

[0105] The sealing hole injection of cement slurry should be carried out by the method of segmented grouting with a bare drill pipe, that is, after injecting a certain height of cement slurry, the drill tool of the corresponding height should be pulled out. Each injection generally does not exceed 100m. After the cement slurry is injected back out of the drill pipe mouth at the bottom of the well, the drill tool must be moved until the drill tool is completely in the casing or pulled out of the wellhead.

[0106] The technical solution provided in the embodiment of the present application utilizes a translation device to enable the drilling rig to move within a limited area, so that multiple feather-shaped branch holes can be cross-constructed simultaneously in the same well site with a limited area. Compared with the method of drilling the main hole and each feather-shaped branch hole one by one and grouting into the main hole and the feather-shaped branch holes, the construction period is greatly shortened, and the ineffective waiting time caused by drilling and grouting is reduced, thereby improving the efficiency of advanced prevention and control of high-pressure water hazards in the coal seam floor.

[0107] By using the overall mobile device of the drilling rig, multiple boreholes can be constructed simultaneously in the same well site with a limited area, reducing the ineffective downtime caused by drilling and grouting, shortening the construction period, rationally optimizing resource allocation, and improving drilling efficiency by 85%. This can provide ideas and important basis for the management of ground areas in coal mines, bring greater economic benefits, avoid the waste of resources caused by grouting stops, and have greater social benefits.

[0108] In one embodiment, the main hole for controlling high-pressure water hazards on the coal floor can also be used to control coal mine gas. The control process may include S201 to S204.

[0109] S201, collect data on coal mine geology, hydrogeology, geophysical exploration, and underground mining.

[0110] S202, analyzing the data and the main hole, taking the main hole as the ground gas hole, and determining the final hole target position of the ground gas hole.

[0111] S203, opening a hole in an underground tunnel of a coal mine and drilling to a final hole target position.

[0112] S204, continue drilling towards the final hole target position based on the main hole, and when the preset distance is reached before the final hole target position, install the target guidance system on the drilling rig, and lower the signal receiving probe into the underground borehole, adjust the ground drilling trajectory according to the magnetic guidance data to drill the remaining hole section, so that the hole section drilled from the underground tunnel is connected with the main hole.

[0113] In order to achieve the successful docking of the ground borehole and the underground tunnel, a docking matching borehole needs to be pre-constructed underground, and after the hole is opened, it is drilled in the direction of the target position of the ground gas hole. Once the casing is drilled, it is lowered. After the casing is lowered and fixed, the orifice high-pressure gate valve should be installed. The lowered casing and gate valve must be pressure tested, and the next step can be carried out only after the pressure test is qualified.

[0114] After drilling to the final hole target position according to the ground drilling final hole position, an expansion drill bit is used to expand the hole at the bottom of the well. The length of the expansion section of the expansion hole is a first preset length (for example, 3m), and the diameter of the expansion section is expanded according to the maximum allowable capacity of the equipment.

[0115] The process of connecting the main hole with the borehole in the underground tunnel can include:

[0116] 1. According to the ground drilling (main hole) construction situation, when the ground drilling reaches the second preset length (for example, 100m) before the final hole target position, the drill is started and the drilling target guidance system is installed.

[0117] 2. Lower the signal receiving probe into the underground borehole, adjust the ground drilling trajectory according to the magnetic guidance data, and drill the remaining hole section to ensure the connection between the two wells.

[0118] 3. Before penetration, reserve a second preset length (for example, 10m), pull out the probe, close the high-pressure gate valve at the orifice, and take safety precautions. To ensure safety, reinforce the orifice casing with anchor rods and cables to prevent the casing from being rushed out by high pressure. When penetration occurs, personnel must evacuate the site and set up a safe isolation area to complete the final connection.

[0119] 4. If the deviation distance between the ground borehole and the target point exceeds the inclination capacity during docking, the underground borehole needs to select a suitable location to re-construct a borehole for docking.

[0120] When the amount of mud returned from the local hole suddenly decreases, the pump pressure suddenly decreases, and the downhole hole casing and gate valve shake, the downhole professional personnel will slightly open the downhole high-pressure gate valve. If mud gushes out, it means that the connection is successful. If there is no mud gushes out, analyze the cause and take measures to connect again until it is successful.

[0121] In one embodiment, after drilling is completed towards the final hole target position based on the main hole, when the deviation between the final hole position of the main hole and the final hole target position exceeds the deflection deviation threshold, a new borehole is constructed in the underground tunnel according to the final hole position of the main hole for docking.

[0122] The method of using the main hole for controlling high-pressure water hazards on the coal floor to control gas in coal mines has achieved "one hole for multiple uses", reduced the total engineering workload of advanced prevention and control of high-pressure water hazards and gas control on the coal floor, improved construction efficiency, and reduced control costs.

[0123] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope of the present application is indicated by the appended claims.

Claims

1. A method for preventing and controlling coal seam floor hazards based on overall movement of a drilling rig, characterized in that: The translation device for assisting the overall movement of the drilling rig comprises: a translation base and a hydraulic cylinder support, wherein the hydraulic cylinder support is used to push and pull the drilling rig to move on the translation base, and the method comprises: Analyze coal mine information, determine the scope of the project and the construction plan, the construction plan includes a drilling design, the drilling design includes a main hole and corresponding multiple feather-shaped branch holes; Drilling the main hole by using the drilling rig; Moving the drilling rig by the translation device to perform cross drilling on the plurality of feather-shaped branch holes; Grouting is injected into the plurality of feather-shaped branch holes through the main hole to isolate the water-conducting channel on the coal seam floor.

2. The method according to claim 1, characterized in that: Also includes: During the drilling construction of the main hole and the multiple feather-shaped branch holes, one or more tests including cuttings logging, drilling logging, hydrological observation, mud property testing, and gamma logging are performed, and the drilling construction plan is adjusted according to the test results of the one or more tests.

3. The method according to claim 2, characterized in that The process of cuttings logging includes: picking up cuttings at a preset position according to the logging interval and the delay time, wherein the delay time is the time required for the cuttings to return from the bottom of the well to the wellhead; Clean the collected rock cuttings according to their lithology; The cleaned rock cuttings are dried.

4. The method according to claim 3, characterized in that The late time is calculated according to the following formula: Among them, t is the cuttings delay time; V is the annular space volume between the wellbore and the drill pipe; Q is the displacement of the drilling pump; D is the well diameter or drill bit diameter; d is the outer diameter of the drill pipe; H is the well depth.

5. The method according to claim 3, characterized in that: The calculation method of the late time is: select a physical object with a size and density within a preset difference with the cuttings, and put the physical object into the drill pipe, record the pump start time after the physical object is put in and the return time of the physical object, calculate the time difference between the pump start time and the return time, and obtain the cycle period; The late time is calculated according to the cycle period using the following formula: t=t1-t0 Among them, t is the delay time; t1 is the cycle period; t0 is the time for the object to descend along the drill pipe to the bottom of the well; V1 is the internal volume of the drill pipe; V2 is the internal volume of the drill collar; d1 is the inner diameter of the drill pipe; d2 is the inner diameter of the drill collar; L1 is the length of the drill pipe; L2 is the length of the drill collar; G is the mud displacement.

6. The method according to claim 2, characterized in that The drilling fluid logging includes: measuring and recording the conventional properties of the drilling fluid once at a first preset time interval, measuring and recording the full properties of the drilling fluid once at a second preset time interval, and continuously measuring and recording the conventional properties of the drilling fluid when drilling into a coal seam hole section or finding abnormal gas display.

7. The method according to claim 1, characterized in that The step of injecting grout into the plurality of feather-shaped branch holes through the main hole comprises: flushing the plurality of pinnate branch holes; Conduct water pressure test to determine the water permeability of unit receiving layer; Determining the density of the slurry according to the water permeability and preparing the slurry; Grouting is performed into the plurality of feather-shaped branch holes through three stages: normal pressure grouting, pressure grouting and high pressure grouting.

8. The method according to claim 7, characterized in that The water permeability can be calculated by the following formula: Among them, q is the water permeability; U is the pressure flow rate in the water pressure test; P is the total pressure acting in the test pressure section in the water pressure test; L is the length of the test pressure section.

9. The method according to claim 1, characterized in that: Also includes: Collect data on coal mine geology, hydrogeology, geophysical prospecting, and underground mining; Analyze the data and the main hole, use the main hole as a ground gas hole, and determine the terminal hole target position of the ground gas hole; Opening a hole in an underground tunnel of a coal mine and drilling a hole to the final hole target position; On the basis of the main hole, drilling continues towards the final hole target position, and when a preset distance is reached before drilling to the final hole target position, a target guidance system is installed on the drilling rig, and a signal receiving probe is lowered into the underground borehole, and the ground drilling trajectory is adjusted according to the magnetic guidance data to drill the remaining hole section, so that the hole section drilled from the underground tunnel is connected to the main hole.

10. The method according to claim 9, characterized in that After drilling is continued towards the final hole target position based on the main hole, when the deviation between the final hole position of the main hole and the final hole target position exceeds the inclination deviation threshold, a new borehole is constructed in the underground tunnel according to the final hole position of the main hole for docking.

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