Grouting reinforcement method for directional drilling of goaf

Abstract

The invention provides a goaf directional drilling grouting reinforcement method which comprises the following steps: S1, determining a goaf treatment engineering grade and a design standard, and delimiting a goaf treatment range according to the engineering grade and the design standard; the method comprises the steps of S1, determining the position, coordinates and spatial arrangement of a drilling target spot, S2, determining the position, coordinates and planar arrangement of a directional well site, wellhead coordinates and planar arrangement of a directional well site, S4, designing a drilling track form and a drilling well bore structure, and S5, designing a drilling track form and a drilling well bore structure, the drilling track form comprising at least one of a straight line-curve form, a straight line-curve-straight line form and a straight line-curve-curve form. And S5, the drilling technology and drilling track control are determined, and drilling and drilling track control are conducted through directional drilling track measurement control equipment, near-bit geosteering equipment and rotary steering drilling equipment. The goaf directional drilling grouting reinforcement method is wide in treatment range, low in treatment cost and low in construction risk.

Description

Technical Field

[0001] The invention relates to the technical field of goaf grouting, and in particular to a goaf directional drilling grouting reinforcement method. Background Art

[0002] As the development of the mining area progresses from shallow to deep, the depth of goaf treatment continues to increase. The traditional technology of using vertical drilling to manage goaf faces many challenges, especially the complex environmental conditions in the goaf. Complex environmental conditions refer to the conditions that restrict the implementation of coal mining subsidence area management, mainly including: complex topography, landforms, environmental protection constraints and other conditions. As the depth of management increases, the length of a single borehole crossing the goaf section relative to the hole depth is getting smaller and smaller (the smaller the goaf drilling rate), the utilization rate of the borehole continues to decrease, and the proportion of drilling costs as an auxiliary process of the project in the total cost of the management project has increased significantly, resulting in its poor economic performance.

[0003] In addition, in actual projects, in order to save project investment, the drilling spacing can only be continuously increased, and the resulting safety hazards are prominent. The greater the depth of treatment, the greater the scope of treatment, and the need for a large number of temporary land acquisitions and construction access roads, further increasing the cost of treatment and the risk of construction. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, an embodiment of the present invention proposes a directional drilling grouting reinforcement method for goaf areas, which has a wide treatment range, low treatment cost and low construction risk.

[0006] The method for directional drilling and grouting reinforcement of goaf areas according to an embodiment of the present invention comprises the following steps:

[0007] S1. Determine the level and design standards of goaf area management engineering, and define the scope of goaf area management according to the engineering level and design standards;

[0008] S2. Determine the position, coordinates and spatial arrangement of the drilling target points within the goaf treatment range. The drilling target points are divided into first grouting target points and second grouting target points. The second grouting target points are arranged along the edge of the goaf treatment range. The ratio of the distance between two adjacent second grouting target points to the distance between two adjacent first grouting target points is 1 / 2 to 2 / 3, and the distance between two adjacent second grouting target points is not more than 20 meters.

[0009] S3, determine the directional well site location, wellhead coordinates and plane layout;

[0010] S4, designing a drilling trajectory shape and a drilling wellbore structure, wherein the drilling trajectory shape includes at least one of a straight line-curve shape, a straight line-curve-straight line shape, and a straight line-curve-curve shape;

[0011] S5. Determine the drilling process and drilling trajectory control, and use directional drilling trajectory measurement and control equipment, near-drill bit geological guidance equipment, and rotary guidance drilling equipment to control the drilling and drilling trajectory.

[0012] The method for directional drilling and grouting reinforcement of goaf areas in the embodiment of the present invention determines the treatment scope according to the spatial distribution and occurrence status of the goaf areas, and determines the branch grouting drilling target position and coordinates in combination with the surface engineering layout. Then, according to the purpose of grouting filling, the target accuracy and target area range are determined in combination with the size of the goaf areas, the development height of the collapse zone and the fracture zone. The drilling arrangement is optimized and the number of drilling holes is reduced, thereby improving the economy and safety of goaf area treatment, reducing the treatment cost, and at the same time reducing the scope of environmental impact, which is conducive to the sustainable development of resources.

[0013] In some embodiments, in step S1,

[0014] The width of the goaf treatment range is determined by calculating the thickness of the overlying rock layer on the upper mountain boundary of the goaf collapse and the movement influence angle, that is: D i =h i cotφ+H i cotβ i , where D i h is the width of overburden movement in the uphill direction of mining collapse; i H is the thickness of the loose layer on the surface in the uphill direction of the mining collapse; i The thickness of the overlying bedrock in the uphill direction of the mining collapse; is the loose layer movement angle; β i It is the impact angle of overlying rock movement in the uphill direction of mining collapse.

[0015] In some embodiments, the depth of the goaf treatment range is 1 to 3 meters below the ground and the goaf collapse floor.

[0016] In some embodiments, in step S2, the following steps are also included:

[0017] The type of directional drilling and the profile of the hole are determined according to the thickness of the Quaternary loose layer, the vertical depth and the horizontal distance of the target point. The type of directional drilling is at least one of a unidirectional feather hole, a bidirectional feather hole, a multi-level branch directional hole and a multi-directional cluster hole.

[0018] In some embodiments, in step S2, the following steps are also included:

[0019] Sort the vertical depth and horizontal distance of each branch hole target point to determine the position and relative relationship of the inclination point and each branch point.

[0020] In some embodiments, in step S4,

[0021] The drilling wellbore structure is one of a two-opening structure, a three-opening structure or a structure combining multiple apertures and casing wall protection.

[0022] In some embodiments, in step S4, the diameter of the opening of the main well of the directional drilling is greater than or equal to 200 mm, and the diameter of the branch hole completion is greater than or equal to 120 mm.

[0023] In some embodiments, in step S4, the following steps are also included:

[0024] The drilling trajectory design includes: the branch point is determined, and the drilling trajectory is gradually moved from the branch point to the target point; the branch point is not determined, and the drilling trajectory is moved from the target point to the branch point step by step; the main hole and branch holes of multiple wells coexist, and the drilling trajectory is carried out in the order of main hole first and then branch holes.

[0025] In some embodiments, in step S4, the following steps are also included:

[0026] Calculate the curvature and length of the curved section, determine the length of each hole section, the vertex angle and azimuth of the starting and ending points of each hole section, and draw a three-dimensional curve graph and a two-dimensional projection graph of the drilling trajectory.

[0027] In some embodiments, the method for directional drilling and grouting reinforcement of goaf areas in the embodiment of the present invention further includes the following steps:

[0028] S6. Prevent accidents in boreholes and implement measures to deal with well collapse. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic flow chart of a method for directional drilling and grouting reinforcement of a goaf area according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0031] like Figure 1 As shown, the method for directional drilling and grouting reinforcement of goaf areas according to an embodiment of the present invention comprises the following steps:

[0032] S1. Determine the level and design standards of goaf governance engineering, and define the scope of goaf governance according to the level and design standards. It is understandable that the level and design standards of goaf governance engineering can be evaluated and analyzed by collecting relevant data such as geological data, mining history, and ground subsidence of the goaf to determine the stability and governance needs of the goaf. According to the evaluation results, the safety level of the goaf governance engineering is determined, such as level 1, level 2, or level 3. Then, the governance design standards are formulated according to the safety level, thereby determining the scope of goaf governance and marking it on the ground.

[0033] In some embodiments, in step S1, the width of the goaf treatment range is determined by calculating the thickness of the overlying rock layer on the upper boundary of the goaf collapse and the movement influence angle, that is: i =h i cotφ+H i cosβ i , where D i h is the width of overburden movement in the uphill direction of mining collapse; i H is the thickness of the loose layer on the surface in the uphill direction of the mining collapse; i The thickness of the overlying bedrock in the uphill direction of the mining collapse; is the loose layer movement angle; β i It is the impact angle of overlying rock movement in the uphill direction of mining collapse.

[0034] The determination of the scope of governance in the goaf area includes two steps: the scope of governance plane and the scope of governance depth in the coal mining subsidence area: the determination of the scope of governance plane in the coal mining subsidence area, that is, the scope of governance plane should be determined by fully considering factors such as the size of the buildings (structures) to be protected, the topography and the formation conditions, etc., which specifically includes three parts: the basic size of protection, the width of the enclosure belt and the width of the impact of mining overburden movement. The determination of the depth range of goaf area governance, preferably, the depth of the goaf area governance range is 1 to 3 meters below the ground to the goaf collapse floor. Since there is a cavity area below the collapse floor of the goaf, if no reinforcement and governance is carried out, the existence of the cavity may cause the ground to continue to sink, and even cause a larger range of ground collapse. Extending the governance range to 1 to 3 meters below the collapse floor can ensure that the cavity is fully filled, thereby effectively preventing ground subsidence and collapse and reducing the risk of re-sinking.

[0035] S2. Within the goaf management range, determine the location, coordinates and spatial arrangement of the drilling target points. The drilling target points are divided into the first grouting target points and the second grouting target points. The second grouting target points are arranged along the edge of the goaf management range. The ratio of the distance between two adjacent second grouting target points to the distance between two adjacent first grouting target points is 1 / 2 to 2 / 3, and the distance between two adjacent second grouting target points is not more than 20 meters.

[0036] It is understandable that the plane layout and spacing of the drilling targets must be determined comprehensively based on field tests, goaf types and characteristics; in areas with rich experience in engineering management, it can be determined based on factors such as mining methods, overburden stratum structure and lithology, recovery rate, roof management methods, gaps in caving zones and fissure zones, fissure distribution and connectivity, and the level of management engineering. Among them, if the outer side of the management project is still a goaf, it is necessary to ensure that the ratio of the distance between two adjacent second grouting targets to the distance between two adjacent first grouting targets is 1 / 2 to 2 / 3, so as to avoid the negative effects of too small spacing between the drilling targets, which will lead to increased engineering costs and reduced construction efficiency.

[0037] In some embodiments, step S2 also includes the following steps: determining the directional drilling type and the hole profile according to the thickness of the Quaternary loose layer, the vertical depth and the horizontal distance of the target point, and the directional drilling type is at least one of a unidirectional feather hole, a bidirectional feather hole, a multi-level branch directional hole and a multi-directional cluster hole.

[0038] It is understandable that unidirectional feather holes can effectively expand the scope of treatment in one direction and reduce interference with other areas. Bidirectional feather holes can effectively treat in two directions at the same time, improving work efficiency. Multi-level branch directional holes can treat different depth layers in a targeted manner to improve the treatment effect. Multi-directional cluster holes start from multiple main holes and concentrate on drilling towards the central area or a certain target to form a cluster structure. Multi-directional cluster holes are suitable for concentrated treatment of a specific area or target, such as groundwater resource development, pollution control, etc. Multi-directional cluster holes can concentrate forces for efficient treatment.

[0039] Therefore, in actual engineering, based on factors such as the thickness of the Quaternary loose layer, the vertical depth and horizontal distance of the target point, the above factors can be comprehensively evaluated to select the most suitable directional drilling type and hole profile to achieve the best treatment effect.

[0040] In some embodiments, step S2 also includes the following steps: sorting the vertical depths and horizontal distances of the target points of each branch hole, and determining the positions and relative relationships of the inclination point and each branch point.

[0041] First, it is necessary to collect or measure the vertical depth and horizontal distance data of each branch hole target. These data are usually obtained through geological exploration, drilling logs, geophysical measurements, etc. The collected data is organized into a table or database format for easy analysis and processing. The data usually includes information such as the name, coordinates (X, Y, Z), vertical depth, and horizontal distance of the target. Use data analysis software or programming languages ​​(such as Python, MATLAB, etc.) to sort the data. Sort by vertical depth or horizontal distance, depending on the design requirements.

[0042] S3. Determine the directional well site location, wellhead coordinates and plan layout.

[0043] It is understandable that the location and layout of the directional well site mainly include the following steps: The location selection of the directional well site should fully consider the topography of the project area, try to avoid unfavorable geological areas such as landslides and mudslides, and combine the traffic road conditions to comprehensively determine the location of the directional well site from the aspects of the cost of the treatment project and the grouting effect; the layout of the well site should follow the principles of efficiency and safety, and make full use of the terrain to save land and facilitate construction on the premise of meeting the different well site area requirements for different types of drilling rigs. Reduce the impact of the well site on the environment and improve the sustainability of the well site; set up sewage collection systems such as sewage pools and sedimentation tanks in the directional well site, and arrange drainage systems around the well site to take flood prevention measures in the rainy season. Strengthen on-site safety management, set up entry instructions and well site safety status reminder signs in conspicuous locations at the well site.

[0044] S4. Designing a drilling trajectory shape and a drilling wellbore structure, wherein the drilling trajectory shape includes at least one of a straight line-curve shape, a straight line-curve-straight line shape, and a straight line-curve-curve shape.

[0045] It is understandable that the drilling trajectory in the form of a straight line-curve starts and ends at a straight line segment, with a curve in the middle. The curve part allows the drilling trajectory to bypass obstacles or adapt to specific geological structures, and can effectively avoid underground obstacles such as rocks, caves, etc., adapt to stratum changes, and reduce damage to drilling tools caused by sudden changes in strata; the drilling trajectory in the form of a straight line-curve-straight line has a curve connecting the two straight line segments. It is suitable for drilling projects that need to start vertically from the ground and then turn horizontally or at a specific angle, suitable for underground pipelines, tunnels and other projects, and can reduce damage to the surface while ensuring construction safety. It is suitable for deep and long-distance drilling operations, improves drilling efficiency and success rate, and facilitates subsequent pipeline installation and maintenance; the drilling trajectory in the form of a straight line-curve-curve consists of two curve segments and a straight line segment in the middle. It is suitable for situations with complex geological conditions and where the drilling direction needs to be adjusted multiple times. It can better adapt to complex and changeable geological structures, reduce uncertainty in the drilling process, and improve the flexibility and applicability of drilling. Especially in areas with varying degrees of softness or hardness of strata or many underground obstacles, it enhances the ability to adjust the drilling trajectory, helps to achieve precise drilling, improves drilling accuracy, and ensures that the drilling trajectory is consistent with design requirements.

[0046] In addition, the drilling trajectory can also adopt a variety of trajectory combinations, such as straight line-curve-straight line-curve-straight line, to ensure drilling efficiency under different working conditions, ensure construction safety and reduce construction costs.

[0047] In some embodiments, in step S4, the drilling wellbore structure is a two-opening structure, a three-opening structure, or a multi-level aperture and casing wall combination structure.

[0048] It can be understood that the two-opening structure means that the well body is divided into two main parts. First, a larger hole is drilled as the first opening, then casing is lowered and cement is carried out, and then a smaller hole is drilled in the casing as the second opening. The two-opening structure reduces the stability problem of the well wall and better supports the well wall. The second opening wellbore is smaller, which is convenient for fine control of drilling direction and trajectory. It is suitable for simpler geological conditions and scenarios with higher requirements for well wall stability. The three-opening structure is based on the two-opening structure, and then a level of wellbore is added. That is, the first opening wellbore is drilled first, then casing is lowered, the second opening wellbore is drilled in the casing, casing is lowered again, and finally the third opening wellbore is drilled in the second opening casing, so as to better adapt to complex geological conditions, especially deep layers or those with In areas with multiple strata of different properties, multi-level casing protection can better control the stability of the well wall and reduce the risk of hole collapse. It is suitable for deep drilling or mining projects that require the insertion of multiple casing layers. The multi-level aperture structure means that the well body is composed of multiple well sections with different apertures. Each well section can be inserted with casing of corresponding sizes and protected by walls. It can be four, five or even more levels according to needs. The multi-level aperture structure greatly improves the adaptability to complex geological conditions. Suitable aperture and casing design can be used in each geological layer of different properties. Through multi-level casing, different strata can be more effectively isolated to prevent fluid cross-talk between strata, enhance the stability of the well wall, reduce construction risks, and improve project safety.

[0049] Preferably, in step S4, the opening diameter of the main well of the directional drilling is greater than or equal to 200 mm, and the completion diameter of the branch hole is greater than or equal to 120 mm. Large-diameter openings can speed up drilling, because a larger drill bit can cut more rock in the same time. The larger completion diameter of the branch hole is conducive to improving the construction efficiency of the branch hole, facilitating the lowering of drilling tools and logging tools, thereby improving construction efficiency. In addition, large-diameter openings in the main well are conducive to forming a stable borehole wall, enhancing borehole stability, and reducing the risk of hole collapse. Larger branch apertures help maintain the stability of the branch hole section, especially in soft or broken rock formations.

[0050] In some embodiments, step S4 also includes the following steps: the drilling trajectory design includes: the branch point has been determined, and the drilling trajectory is gradually moved from the branch point to the target point; the branch point has not been determined, and the drilling trajectory is moved from the target point to the branch point step by step; the main hole and branch holes of multiple wells coexist, and the drilling trajectory is carried out in the order of main hole first and then branch holes.

[0051] It can be understood that the drilling trajectory also includes the selection of the locations of the inclination points and branch points. The locations of the inclination points and branch points should be selected in stable rock formations, avoiding hard, brittle, broken rock formations, caves and sand layers; the spacing between the upper and lower inclination points should be determined according to the drillability of the formation, and the minimum spacing should not be less than 5m; the locations of the inclination points of different branch holes should be sorted and determined according to the water-to-vertical ratio of each branch hole. The inclination points of branch holes with large water-to-vertical ratios should be arranged in the upper part of the borehole, and the inclination points of branch holes with small water-to-vertical ratios should be arranged in the deep part of the borehole; inclination points, branch points and inclination hole sections shall not be selected in weathering zones.

[0052] In addition, in the drilling and cementing process, after the directional drilling casing is lowered and installed in place, petroleum cement is used for cementing. The density of cement slurry should not be less than 1.85g / cm 3 When the cement slurry returns to the ground from the annular space between the casing and the well wall, the effect can be terminated. After the cementing is completed, it must be waited for 24 hours for pressure testing. The test pressure is 1.0 to 1.2 times the designed grouting pressure. If the pressure drop is less than 20% and does not exceed 0.50MPa within 30 minutes, it is considered qualified and the cementing quality evaluation is carried out.

[0053] In some embodiments, step S4 also includes the following steps: calculating the curvature and length of the curved segment, determining the length of each hole segment, the vertex angle and azimuth of the starting and ending points of each hole segment, and drawing a three-dimensional curve graph and a two-dimensional projection graph of the drilling trajectory.

[0054] It is understandable that accurate calculation and drawing can ensure that drilling is carried out along the predetermined trajectory. Understanding the specific shape and parameters of the drilling trajectory helps to optimize the wellbore structure design. Three-dimensional curve graphs and two-dimensional projection graphs can provide references for subsequent drilling operations, such as side drilling and branch hole construction, thereby achieving problem diagnosis and guiding subsequent construction.

[0055] S5. Determine the drilling process and drilling trajectory control, and use directional drilling trajectory measurement and control equipment, near-drill bit geological guidance equipment, and rotary guidance drilling equipment to control the drilling and drilling trajectory.

[0056] Directional drilling trajectory measurement and control equipment can be divided into wired while drilling system and wireless while drilling system according to the different signal media; the wired while drilling measurement system transmits measurement signals through the center cable-type drilling tool, keeps the drill pipe column without rotating during drilling, relies on the single-bend screw motor at the bottom of the hole to drive the drill bit to rotate for rock crushing drilling, continuous deflection, and implement continuous sliding directional drilling; the wireless while drilling measurement system frees directional drilling from dependence on cable-type drilling tools, realizes the transition of MWD signal from wired transmission to wireless transmission, and develops a composite directional drilling equipment for wireless while drilling measurement of special-shaped drill pipes (including triangular drill pipes, spiral drill pipes, etc.).

[0057] Directional drilling trajectory measurement and control equipment can be divided into: measurement while drilling equipment (MWD), logging while drilling equipment (LWD), and seismic detection while drilling equipment (SWD) according to different measurement parameters.

[0058] The Measure While Drilling equipment is mainly used to measure the wellbore trajectory parameters while drilling, including: well inclination, azimuth, tool face angle and auxiliary parameters such as temperature, etc. It is currently the most commonly used directional measurement method.

[0059] Logging While Drilling (LWD) is a measurement system based on MWD that has the functions of formation data acquisition and geological guidance. In addition to the acquisition of MWD measurement parameters, the system adds the acquisition of formation evaluation parameters (such as resistivity, natural gamma, neutron density, etc.) and drilling engineering parameters (drilling rig torque, vibration, drilling pressure, etc.); the system can determine the formation lithology changes and formation fluid characteristics around the wellbore through near-bit gamma rays, resistivity and other data, and can use near-bit inclination parameters to predict the relative position and development trend of the wellbore trajectory in the formation, providing guidance for subsequent drilling.

[0060] Seismic While Drilling (SWD) is a new interdisciplinary equipment developed on the basis of traditional ground seismic detection methods and in combination with drilling engineering on the existing vertical seismic profiling (VSP) equipment. Its principle is to use the vibration of the rotating drill bit during drilling as the downhole seismic source, bury the detector at the top of the drill pipe and near the wellbore, and receive the drill bit vibration signal through the drill pipe and the formation respectively; the drill pipe signal and the ground wave detector signal are connected through the cross-correlation device to obtain the inverse VSP information of the wellbore seismic wave, so as to realize the continuous collection of direct wave information and reflected wave information during the continuous drilling process of the roller drill bit.

[0061] The near-bit geological guidance equipment system consists of several parts, including a measuring and transmission motor, positive pulse wireless measurement while drilling, wireless signal reception, ground information processing and guidance decision software, etc., to realize the processing and guidance decision of drilling geological data information; the equipment has the characteristics of short measurement blind area, high instrument resolution, fast data transmission speed, and strong signal processing and recognition capabilities. The system installs the well inclination, azimuth and gamma sensors in a certain arrangement on the curved shell of the power drill, realizing integration with the induction resistivity meter; by using short transmission equipment, the measurement data is transmitted to the ground via MWD to obtain the best well inclination, azimuth parameters, gamma and resistivity information, thereby realizing the selection and control of the best position for the drill to pass through the formation.

[0062] Rotary steerable drilling equipment (RSS) is a new type of automatic drilling steering control equipment, which can complete the steering action in real time during the rotary drilling of the drill string; compared with the current sliding drilling directional equipment, this equipment has the characteristics of high wellbore trajectory control accuracy, flexible orientation, small friction torque, and low accident rate in the well. It can significantly improve the drilling capacity and adapt to complex geological conditions underground; this equipment can achieve sliding while rotating, and the wellbore trajectory formed is smoother than that of motor-guided drilling tools, which is one of the main development directions of directional drilling equipment.

[0063] That is to say, the directional drilling grouting reinforcement method for goaf areas of the embodiment of the present invention can also integrate and process multi-source geological data, extract useful information data, and establish a digital model of geological structure with a certain accuracy through various rules, simulate the spatial structure of the geological body with the greatest realism, and intuitively display the underground situation in front of the staff, thereby providing scientific assistance to the design and implementation of the project.

[0064] In some embodiments, the goaf directional drilling grouting reinforcement method of the embodiment of the present invention further includes the following steps: S6, preventing accidents in the borehole and implementing measures to deal with well collapse.

[0065] It is understandable that since the purpose of the drilling operation is to grout the goaf, drilling in the dynamic fractured strata, especially in the bottom exploration section, will cause drilling fluid leakage; after the drilling fluid leaks, it must not be plugged, and drilling must be carried out to eliminate the leakage. At the same time, close attention should be paid to the transmission of the MWD measurement while drilling signal, and preparations should be made at any time to lift the drill and inject grout after the signal disappears after the loss of return leakage, and the following preventive measures should be taken: achieving balanced drilling is the prerequisite for safe drilling; adopting a reasonable drill tool structure and appropriately increasing the annular flow section; ensuring good wellbore quality is crucial to prevent doglegs; maintaining the stability of the drilling fluid, minimizing the water loss of the drilling fluid, enhancing the wall-building and plugging ability of the drilling fluid, so that it can form a thin and dense mud cake on the well wall in a short time, and ensuring the rheological properties of the drilling fluid, Keep the well wall and the drill collar annulus in a laminar state to reduce the hydraulic erosion of the well wall by the slurry flow; control the drilling and lowering speeds, and the mud pump should be started and operated smoothly to try to reduce any form of excitation pressure and suction pressure. In the seriously collapsed well section, the further mechanical damage of the drilling tool to the well wall should be reduced; when drilling is stopped for a long time in the well, the circulation position of the drilling fluid must be constantly changed, and fixed-point circulation is prohibited; when drilling is started, the circulating fluid in the well should be continuously replenished to maintain the pressure balance in the well. If gas invasion occurs underground, the gas should be removed in time and the pressure of the liquid column should be kept at a normal state; if leakage occurs underground, measures should be taken to try the best to maintain the pressure of the liquid column in the well, and effectively prevent and plug leakage; adhere to the reaming system during drilling to ensure that the wellbore is unobstructed during construction; in the well section with frequent collapse, adjust the mud properties in advance.

[0066] The measures for handling well collapse include: optimizing and adjusting the performance of drilling fluid to make it have good rock-carrying, slag-discharging and suspension capabilities; trying to maintain smooth circulation in the well, moving the drill bit up and down, and keeping the drill bit in a free state. If the circulation pressure increases, even if the displacement is reduced, the purpose of maintaining circulation must be achieved; if a well collapse occurs during drilling, the drill bit should be immediately lifted off the bottom of the well. Except for connecting a single root and tripping the drill, the rotation of the drill bit should not be interrupted, and the speed should be strictly controlled within 80 rpm; increase the circulation displacement to bring the collapsed material out of the ground in time. If the collapse is serious, replace it with an ordinary drill bit. Each time a single thread is connected, the hole must be reamed, and the single thread must be connected only after the bottom hole circulation, so as to achieve "late stop and early start", and the drill can be started only after the drilling fluid has been thoroughly circulated; according to the nature of the operation, the hole must be reamed or reversed to restore the well to normal; if there is still severe resistance and torque in the well after multiple reaming, the drilling fluid density must be increased, but sufficient margin should be left to ensure that any pressure fluctuation will not leak the formation; if the well has collapsed and the drill is stuck, it is recommended to move the drill bit up and down if possible to allow the collapsed material to fall below the drill bit. If the drill bit is stuck, it must be released in time with a jar, as it is crucial to lose time.

[0067] Therefore, the directional drilling and grouting reinforcement method for goaf areas of the embodiment of the present invention determines the treatment scope according to the spatial distribution and occurrence status of the goaf areas, and determines the branch grouting drilling target position and coordinates in combination with the surface engineering layout. Then, according to the purpose of grouting filling, combined with the goaf area size, collapse zone and fracture zone development height, the target accuracy and target area range are determined, the drilling arrangement is optimized, and the number of drilling holes is reduced, thereby improving the economy and safety of goaf area treatment, reducing treatment costs, and at the same time reducing the scope of environmental impact, which is conducive to the sustainable development of resources.

[0068] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0069] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0070] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0071] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0072] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0073] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for directional drilling and grouting reinforcement of goaf areas, characterized in that: The following steps are involved: S1. Determine the level and design standards of goaf area management engineering, and define the scope of goaf area management according to the engineering level and design standards; S2. Determine the position, coordinates and spatial arrangement of the drilling target points within the goaf treatment range. The drilling target points are divided into first grouting target points and second grouting target points. The second grouting target points are arranged along the edge of the goaf treatment range. The ratio of the distance between two adjacent second grouting target points to the distance between two adjacent first grouting target points is 1 / 2 to 2 / 3, and the distance between two adjacent second grouting target points is not more than 20 meters. S3, determine the directional well site location, wellhead coordinates and plane layout; S4, designing a drilling trajectory shape and a drilling wellbore structure, wherein the drilling trajectory shape includes at least one of a straight line-curve shape, a straight line-curve-straight line shape, and a straight line-curve-curve shape; S5. Determine the drilling process and drilling trajectory control, and use directional drilling trajectory measurement and control equipment, near-drill bit geological guidance equipment, and rotary guidance drilling equipment to control the drilling and drilling trajectory.

2. The method for directional drilling and grouting reinforcement of goaf areas according to claim 1, characterized in that: In step S1, The width of the goaf treatment range is determined by calculating the thickness of the overlying rock layer on the upper mountain boundary of the goaf collapse and the movement influence angle, that is: D i =h i cotφ+H i cotβ i , where D i h is the width of overburden movement in the uphill direction of mining collapse; i H is the thickness of the loose layer on the surface in the uphill direction of the mining collapse; i The thickness of the overlying bedrock in the uphill direction of the mining collapse; is the loose layer movement angle; β i It is the impact angle of overlying rock movement in the uphill direction of mining collapse.

3. The method for directional drilling and grouting reinforcement of goaf area according to claim 2, characterized in that: The depth of the goaf area management range is 1 to 3 meters below the ground to the goaf collapse bottom.

4. The method for directional drilling and grouting reinforcement of goaf area according to claim 1, characterized in that: In step S2, the following steps are also included: The type of directional drilling and the profile of the hole are determined according to the thickness of the Quaternary loose layer, the vertical depth and the horizontal distance of the target point. The type of directional drilling is at least one of a unidirectional feather hole, a bidirectional feather hole, a multi-level branch directional hole and a multi-directional cluster hole.

5. The method for directional drilling and grouting reinforcement of goaf area according to claim 4, characterized in that: In step S2, the following steps are also included: Sort the vertical depth and horizontal distance of each branch hole target point to determine the position and relative relationship of the inclination point and each branch point.

6. The method for directional drilling and grouting reinforcement of goaf area according to claim 1, characterized in that: In step S4, The drilling wellbore structure is one of a two-opening structure, a three-opening structure or a structure combining multiple apertures and casing wall protection.

7. The method for directional drilling and grouting reinforcement of goaf area according to claim 6, characterized in that: In step S4, the diameter of the opening of the main well of the directional drilling is greater than or equal to 200 mm, and the diameter of the branch hole completion is greater than or equal to 120 mm.

8. The method for directional drilling and grouting reinforcement of goaf area according to claim 7, characterized in that: In step S4, the following steps are also included: The drilling trajectory design includes: the branch point is determined, and the drilling trajectory is gradually moved from the branch point to the target point; the branch point is not determined, and the drilling trajectory is moved from the target point to the branch point step by step; the main hole and branch holes of multiple wells coexist, and the drilling trajectory is carried out in the order of main hole first and then branch holes.

9. The method for directional drilling and grouting reinforcement of goaf area according to claim 8, characterized in that: In step S4, the following steps are also included: Calculate the curvature and length of the curved section, determine the length of each hole section, the vertex angle and azimuth of the starting and ending points of each hole section, and draw a three-dimensional curve graph and a two-dimensional projection graph of the drilling trajectory.

10. The method for directional drilling and grouting reinforcement of goaf areas according to any one of claims 1 to 9, characterized in that: The following steps are also included: S6. Prevent accidents in boreholes and implement measures to deal with well collapse.

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