A method for exploring and treating a collapse column based on ground directional drilling

Abstract

The present application belongs to the technical field of coal mine geological guarantee and hydrogeological disaster prevention, and specifically relates to a collapse column exploration and treatment method based on ground directional drilling, which comprises the following steps: directional horizontal hole group Z1 adopts a lower, upper and middle treatment mode, first, the middle two treatment branch holes are drilled at the edge of the four ash along the fissure development zone to determine the boundary of the collapse column; second, the lower two treatment branch holes are drilled along the five ash on the profile to perform grouting treatment on the position below the collapse column cutting position; then, the upper two treatment branch holes are drilled along the one ash on the profile to perform grouting treatment on the position above the collapse column cutting position; finally, the remaining part is treated by grouting with the three treatment branch holes in the middle, and three mobile holes are additionally arranged to supplement the reinforcement of the collapse column; each treatment branch hole in directional cluster hole group J1 is drilled downward from the top of the collapse column to supplement the grouting reinforcement of the collapse column; the directional horizontal hole group Z1 and the directional cluster hole group J1 are combined to achieve the treatment purpose.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal mine geological guarantee and hydrogeological disaster prevention and control, and particularly relates to a collapse column exploration and treatment method based on ground directional drilling. BACKGROUND

[0002] In the process of coal mining, the collapse column is a special and difficult-to-treat geological structure, the internal rock of which is broken and loose in structure, and is easy to form a vertical water channel, so that the upper aquifer and the lower aquifer are in hydraulic connection. If it is left unattended, it will cause mine water inrush accidents, and even well flooding accidents in serious cases.

[0003] At present, the treatment method for treating the collapse column includes plugging the water channel, and the main plugging method for the water channel is grouting reinforcement. The traditional method mainly uses underground vertical drilling or inclined drilling grouting, and has problems of limited treatment range, low grouting precision and unstable effect, especially for the collapse column, the development boundary and water conductivity of which are uncertain, which further increases the treatment difficulty.

[0004] Therefore, a grouting treatment method with high precision and reliable effect is needed to completely plug the vertical water channel and cut off the hydraulic connection between the upper and lower aquifers. SUMMARY

[0005] The purpose of the present application is to provide a collapse column exploration and treatment method based on ground directional drilling, which completely plugs the vertical water channel and cuts off the hydraulic connection between the upper and lower aquifers, and eliminates the influence of the collapse column on coal seam mining.

[0006] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0007] A collapse column exploration and treatment method based on ground directional drilling, comprising the following steps:

[0008] S1, the position of the collapse column developed in the exploration area is explored by high-density three-dimensional seismic exploration, and the physical parameters of the collapse column from top to bottom in 72 coal, 82 coal, Taiyuan group and Ordovician limestone layers are obtained;

[0009] S2, hydrological long observation holes are drilled in three groups of layers of limestone in the upper group of Taiyuan group, limestone in the middle group of Taiyuan group and limestone in Ordovician group, and pumping test is carried out to obtain corresponding hydrogeological parameters and determine the hydraulic connection between the aquifers in the collapse column;

[0010] S3, selecting lower, upper and middle treatment modes, grouting the first to fifth limestone sections in the collapse column body;

[0011] In the directional horizontal hole plane, the collapse column development boundary is taken as the treatment range, and a directional horizontal hole group Z1 is arranged in the treatment range, and the directional horizontal hole group Z1 includes nine treatment branch holes and three mobile branch holes;

[0012] The nine treatment branch holes are Z1-1 hole, Z1-2 hole, Z1-3 hole, Z1-4 hole, Z1-5 hole, Z1-6 hole, Z1-7 hole, Z1-8 hole and Z1-9 hole, and the three mobile branch holes are Z1-mobile 1 hole, Z1-mobile 2 hole and Z1-mobile 3 hole.

[0013] The Z1-1 hole, the Z1-2 hole, the Z1-3 hole, the Z1-4 hole and the Z1-5 hole are horizontal exploration treatment holes, the Z1-6 hole and the Z1-7 hole are upper sealing holes and are located above the horizontal exploration treatment holes, the Z1-8 hole and the Z1-9 hole are lower sealing holes and are located below the horizontal exploration treatment holes, and the Z1-mobile 1 hole, the Z1-mobile 2 hole and the Z1-mobile 3 hole are supplementary reinforcement holes.

[0014] S4, the hole for treatment further includes a ground directional from hole, and the ground directional from hole is used for supplementally grouting and reinforcing the upper column body of the collapse column;

[0015] In the directional from hole plane, the collapse column development boundary is taken as the treatment range, and a directional from hole group J1 is arranged, and the directional from hole group J1 includes six treatment branch holes and two mobile branch holes.

[0016] The six treatment branch holes are J1-1 hole, J1-2 hole, J1-3 hole, J1-4 hole, J1-5 hole and J1-6 hole, and the two mobile branch holes are J1-mobile 1 hole and J1-mobile 2 hole.

[0017] The J1-1 hole, the J1-2 hole, the J1-3 hole, the J1-4 hole, the J1-5 hole and the J1-6 hole are exploration treatment holes, and the J1-mobile 1 hole and the J1-mobile 2 hole are supplementary reinforcement holes.

[0018] Preferably, for the step S3, specifically, the step S3 includes the following steps.

[0019] S31, the collapse column development boundary is found out, the Z1-1 hole, the Z1-2 hole, the Z1-3 hole, the Z1-4 hole and the Z1-5 hole are drilled along the four ash layer positions, wherein the Z1-1 hole and the Z1-2 hole are drilled along the edge of the fracture development belt, the collapse column boundary is determined through the changes of the rock debris, drilling time and drilling fluid consumption in the drilling process, if a large amount of drilling fluid is lost or the water pressure test is lost in the drilling process, the hole is directly sealed at this time, and then the suspected collapse column boundary is further explored by continuously extending outward by 20-30 m until the drilling hole enters the normal stratum, and the collapse column boundary is determined through the above steps.

[0020] S32, after the boundary is found, firstly, Z1-8 hole and Z1-9 hole are drilled to 20-30 m below the four ash in the profile, the drilling trajectory is drilled to the final hole position in the five ash layer position before entering the collapse column front, the hole plane interval is 40-80 m, and the position below the collapse column cutting position is treated by grouting;

[0021] Secondly, Z1-6 hole and Z1-7 hole are drilled upwards along the four ash in the profile, the drilling trajectory is drilled to the final hole position in the five ash layer position before entering the collapse column front, the plane hole interval is 40-80 m, and the position above the collapse column cutting position is treated by grouting;

[0022] Finally, Z1-3 hole, Z1-4 hole and Z1-5 hole located in the middle position of Z1-1 hole and Z1-2 hole are used to treat the middle position of the collapse column cutting position by grouting.

[0023] S33, Z1-motor 1 hole, Z1-motor 2 hole and Z1-motor 3 hole are used to supplement the reinforcement of the collapse column according to the exploration and treatment situation.

[0024] Preferably, for step S4, specifically, it comprises:

[0025] S41, exploration and treatment holes J1-1 hole, J1-2 hole, J1-3 hole, J1-4 hole, J1-5 hole and J1-6 hole are drilled to the first to fourth ash layer position in turn through 72 coal seam and 82 coal seam;

[0026] Wherein, the directional from hole group J1 is drilled to the bottom in the 72 coal seam roof, and the final hole is in the four ash layer position, the final hole interval is 40 m, the grouting treatment effect of the collapse column is determined by the change of rock debris, drilling time and drilling fluid consumption during drilling, if a large amount of drilling fluid is lost or the water pressure test pressure is less than or equal to 10 MPa during drilling, the collapse column is supplemented by grouting treatment;

[0027] S42, J1-motor 1 hole and J1-motor 2 hole are used to supplement the reinforcement of the collapse column according to the exploration and treatment situation.

[0028] Preferably, the J1-1 hole, J1-2 hole, J1-3 hole, J1-4 hole, J1-5 hole and J1-6 hole of the directional from hole group J1 are arranged in an increasing manner according to the 60° azimuth angle from the drilling center.

[0029] Compared with the prior art, the present application has the following advantages:

[0030] The present application adopts the treatment mode of lower, upper and middle, firstly, Z1-1 hole and Z1-2 hole are used to find out the boundary of the collapse column cutting position, after the boundary is found out, Z1-8 hole and Z1-9 hole are used to carry out grouting treatment below the collapse column cutting position, secondly, Z1-6 hole and Z1-7 hole are used to carry out grouting treatment above the collapse column cutting position, finally, Z1-3 hole, Z1-4 hole and Z1-5 hole which are located in the middle position of Z1-1 hole and Z1-2 hole are used to carry out grouting treatment on the remaining part, so as to form a conical plugging water channel, cut off the hydraulic connection between Taiyuan and Ordovician limestone by grouting, eliminate the influence of the collapse column on coal seam mining, and solve the technical problems that the diffusion path of the slurry in the complex fracture network of the collapse column is difficult to control accurately and the plugging effect is not ideal.

[0031] Through the integrated process of exploration-treatment-verification of the collapse column, the exploration and treatment holes J1-1 hole, J1-2 hole, J1-3 hole, J1-4 hole, J1-5 hole and J1-6 hole of the directional from type hole group J1 pass through 72 coal seam and 82 coal seam in turn, drill into the first to fourth ash layer, and treat the upper part of the collapse column cutting, each branch hole of the construction is an exploration hole, which can explore the development range of the collapse column, is a treatment hole, which realizes grouting treatment while exploring, is a verification hole, which verifies the grouting treatment effect, changes the separate construction of the exploration hole, the treatment hole and the verification hole, the low engineering efficiency and the situation that the information cannot guide the treatment in real time, realizes the treatment idea from the underground treatment to the upper treatment, achieves the purpose of accurate exploration, and forms a complete and systematic technical scheme. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The profile schematic diagram of the directional horizontal hole group Z1 and the directional from type hole group J1 of the collapse column exploration and treatment method based on the ground directional drilling is provided for the present application.

[0033] Figure 2 The plane schematic diagram of the directional horizontal hole group Z1 of the collapse column exploration and treatment method based on the ground directional drilling is provided for the present application.

[0034] Figure 3 The treatment branch hole section schematic diagram of the directional horizontal hole group Z1 of the collapse column exploration and treatment method based on the ground directional drilling is provided for the present application.

[0035] Figure 4 The mobile branch hole section schematic diagram of the directional horizontal hole group Z1 of the collapse column exploration and treatment method based on the ground directional drilling is provided for the present application.

[0036] Figure 5 The plane schematic diagram of the directional from type hole group J1 of the collapse column exploration and treatment method based on the ground directional drilling is provided for the present application. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application.

[0038] Embodiment one

[0039] In the process of coal mining, collapse column is a special and difficult to manage geological structure, its internal rock is broken, loose structure, easy to form vertical water channel, so that the upper aquifer such as Taihuashui and the lower aquifer such as Ordovician limestone have hydraulic connection, leading to the increase of mine water inflow, even causing water inrush accident, seriously threatening the safety production of coal mine.

[0040] Reference Figures 1-5 A kind of collapse column exploration and management method based on ground directional drilling, comprising the following steps,

[0041] S1, according to high-density three-dimensional seismic exploration, one collapse column with a diameter greater than 20m is found to develop in the coal seam in the exploration area, the long axis is 44m and the short axis is 41m in the 72 coal seam, the area is about 1400m 2 ; the long axis is 64m and the short axis is 56m in the 82 coal seam, the area is about 2820m 2 ; the long axis is 86m and the short axis is 63m in Taihuashui, the area is about 4160m 2 ; the long axis is 95m and the short axis is 78m in Ordovician limestone, the area is about 5820m 2 ;

[0042] S2, three ground drillings of supplementary exploration engineering construction, 2020-T1 hole belongs to Taiyuan group upper group limestone hole, 2020-T3 hole belongs to Ordovician limestone hole, 2022-Taihuashui observation 2 hole belongs to Taiyuan group middle group limestone hole, all of which carry out pumping test and obtain corresponding hydrogeological parameters, to determine the hydraulic connection between each group of aquifers in the collapse column, the results show that there is a vertical water channel in this area, and Taihuashui and Ordovician limestone have direct hydraulic connection. The monitoring data before management shows that Taiyuan group upper group limestone, middle group limestone and Ordovician limestone show unified water level characteristics.

[0043] S3, select lower, upper and middle management mode, grouting in one to five limestone segments in the collapse column body, the grouting thickness is 60m, and the vertical water channel is blocked.

[0044] Among them, the development boundary of the collapse column is expanded by 20m on the plane of the directional horizontal hole as the management range, the directional horizontal hole group Z1 is arranged in the management range, the directional horizontal hole group Z1 includes 9 management branch holes and 3 mobile branch holes, and a single directional horizontal hole group Z1 can realize the exploration and management of the collapse column, thereby reducing the construction cost, saving the construction land occupation and relieving the environmental protection pressure;

[0045] 9 governance branch holes are Z1-1 hole, Z1-2 hole, Z1-3 hole, Z1-4 hole, Z1-5 hole, Z1-6 hole, Z1-7 hole, Z1-8 hole, Z1-9 hole, 3 motor branch holes are Z1-motor 1 hole, Z1-motor 2 hole, Z1-motor 3 hole;

[0046] Among them, Z1-1 hole, Z1-2 hole, Z1-3 hole, Z1-4 hole, Z1-5 hole are horizontal exploration and management holes, Z1-6 hole, Z1-7 hole are upper sealing holes, which are above the horizontal exploration and management holes, Z1-8 hole, Z1-9 hole are lower sealing holes, which are below the horizontal exploration and management holes, Z1-motor 1 hole, Z1-motor 2 hole, Z1-motor 3 hole are supplementary reinforcement holes;

[0047] For step S3, specifically, it includes:

[0048] S31, find out the development boundary of the collapse column, Z1-1 hole, Z1-2 hole, Z1-3 hole, Z1-4 hole, Z1-5 hole are drilled along the four ash layer; wherein Z1-1 hole, Z1-2 hole are drilled along the edge of the fracture development zone, the collapse column boundary is determined by the changes of rock debris, drilling time and drilling fluid consumption during drilling, if a large amount of drilling fluid loss occurs during drilling or pressure test loses pressure, at this time, the hole is directly sealed, then continue to expand 20-30m to explore the boundary of the collapse column, until the borehole enters the normal stratum, so as to determine the boundary of the collapse column repeatedly;

[0049] S32, after the boundary is found out, firstly, Z1-8 hole, Z1-9 hole are drilled 20-30m below the four ash in the profile, the final hole position is in the five ash layer, the hole plane distance is 40-80m, the lower part of the collapse column cutting position is treated by grouting; secondly, Z1-6 hole, Z1-7 hole are drilled 20-30m upward along the four ash in the profile, the final hole is in the one ash, the plane hole distance is 40-80m, the upper part of the collapse column cutting position is treated by grouting; finally, Z1-3 hole, Z1-4 hole, Z1-5 hole which are located in the middle position of Z1-1 hole and Z1-2 hole are used to treat the remaining part by grouting, forming a conical plugging water channel, cutting off the hydraulic connection between the Taiyuan and Ordovician ash through grouting, eliminating the influence of the collapse column on coal mining, solving the technical problems of difficult to accurately control the diffusion path of the slurry in the complex fracture network of the collapse column and poor plugging effect;

[0050] S33, use Z1-motor 1 hole, Z1-motor 2 hole, Z1-motor 3 hole to supplement and reinforce the collapse column according to the exploration and management situation.

[0051] Among them, for the case that the horizontal hole group is arranged on one side and the other side may not be well managed, the length of the horizontal section can be appropriately extended according to the actual exploration results of the borehole to ensure that the end at least exceeds the collapse column boundary by 20m;

[0052] After the implementation of the directional horizontal hole group Z1 of the grouting project, the target layer hydraulic system presents significant differentiation: the 2020-T1 hole still maintains a 2.0 MPa orifice pressure after the grouting stops and the pressure is stable, compared with the 2020-T3 hole-12.0 m water level elevation and the 2022-Taigui observation 2 hole 0.22 MPa orifice pressure, forming an obvious hydraulic gradient, confirming that the hydraulic connection channel between the upper group limestone, the middle group limestone and the Ordovician limestone of the Taiyuan group has been effectively blocked.

[0053] S4, the hole for treatment also includes a ground directional from hole, and the ground directional from hole is used for supplementary grouting reinforcement on the upper column body of the collapse column;

[0054] The development boundary of the collapse column is expanded by 20 m on the plane of the directional from hole as the treatment range, the collapse column body is guaranteed to be out of the collapse column, then enters the complete rock stratum section, the directional from hole group J1 is set, the directional from hole group J1 includes a total of 6 treatment branch holes and 2 mobile branch holes, and the 6 branch holes are arranged in an increasing manner according to a 60° azimuth angle from the center of the drilling hole;

[0055] The 6 treatment branch holes are respectively J1-1 hole, J1-2 hole, J1-3 hole, J1-4 hole, J1-5 hole and J1-6 hole, and the 2 mobile branch holes are respectively J1-mobile 1 hole and J1-mobile 2 hole;

[0056] The J1-1 hole, the J1-2 hole, the J1-3 hole, the J1-4 hole, the J1-5 hole and the J1-6 hole are exploration and treatment holes, the J1-mobile 1 hole and the J1-mobile 2 hole are supplementary reinforcement holes, and a complete and systematic technical scheme is formed.

[0057] For step S4, specifically, the following steps are included:

[0058] S41, the exploration and treatment holes J1-1 hole, J1-2 hole, J1-3 hole, J1-4 hole, J1-5 hole and J1-6 hole drill through the 72 coal seam and the 82 coal seam in sequence and drill into the first to fourth ash layer;

[0059] The directional from hole group J1 is drilled to the bottom in the 72 coal seam roof and is drilled to the end in the fourth ash layer, and the end hole spacing is 40 m, the grouting treatment effect of the collapse column is determined through the changes of the rock cuttings, drilling time and drilling fluid consumption in the drilling process, and if a large amount of drilling fluid is lost or the water pressure test pressure is low in the drilling process, the collapse column is supplemented with grouting treatment.

[0060] S42, the J1-mobile 1 hole and the J1-mobile 2 hole are used to supplement and reinforce the collapse column according to the exploration and treatment.

[0061] During the construction of J1 hole group, the hole pressure of 2020-T1 hole was stabilized at 1.1 MPa, the hole water level of 2020-T3 hole was continuously kept at-7.8 m elevation, and the interlayer hydraulic system did not appear abnormal fluctuation, further verifying that the new water channel was not formed between the one-to-two lime-shale system and the one-to-five lime-shale system, marking that the target layer isolation of the collapse column grouting plugging project was successfully achieved.

[0062] Among them, the borehole structure is a three-opening well diameter structure commonly used in directional holes, the first opening diameter D3 is 311 mm, down to the complete bedrock surface, φ244.48×8.94 mm through the casing is lowered to isolate the topsoil layer, and the cementing returns to the orifice; the second opening diameter D2 is 215.9 mm, down to the target interval, that is, the four lime of directional horizontal hole and the top of 72 coal of directional cluster hole, φ177.8×8.05 mm through the casing is lowered, and the cementing returns to the orifice; the third opening diameter D1 is 152 mm, the bare hole section to the final hole position.

[0063] It should be noted that directional drilling while drilling must be used, and the drilling trajectory is monitored and checked in real time to ensure that the inclination, horizontal displacement and full angle change rate meet the requirements;

[0064] The hole orientation is strictly controlled during the build-up section, and the orientation is controlled within ±2° of the designed orientation. The closed orientation of the build-up section should not exceed 1.5° of the designed hole orientation;

[0065] Regular inspection and calibration of the drilling monitoring equipment should be strengthened to ensure that the equipment is sensitive and accurate, and the drilling trajectory change is closely monitored. The distance between each monitoring point should not be more than 10 m, the error of the drilling trajectory of the build-up section and the designed trajectory should not be more than 2 m, and the error of the key drop point should not be more than 1.5 m;

[0066] According to the different drilling time of different well depth, the rock stratum is accurately positioned; the loose layer does not need to take sand sample, but the bedrock interface must be determined; every 1 m of the loose layer is taken to the completion of drilling, and the identification is done well, the drilling cuttings logging table is sorted and summarized on site, and the stratum is preliminarily judged and divided;

[0067] The drilling time logging interval requirement is: 1 point per 1 m from the bedrock section to the completion of drilling;

[0068] Drilling fluid logging: full performance test every 8 hours; density and viscosity performance test every 2 hours; when gas show anomaly is found in coal seam well section, continuous measurement of drilling fluid density and viscosity is required, and good records are kept;

[0069] The purpose of simple hydrological observation is to obtain the true water level of the injection section, and comprehensively analyze the regional groundwater flow field, water-rich characteristics and drillability within the treatment range. Measure the water level once after each drilling and before each drilling. Measure the water level once before each water pressure test; record the drilling fluid consumption every 2 hours of drilling, and record the drilling fluid consumption every 1 hour after entering the limestone. If the drilling fluid consumption is less than 1 hour but more than 30 minutes, the drilling fluid consumption should also be observed; If water leakage, hole collapse, hole shrinkage, and other phenomena occur during drilling, the layer, depth, and value of the occurrence should be recorded in detail, and important links such as diameter change and layer change should also be recorded in detail. Consumption observation: when drilling fluid leakage is found, observe every 10-30 minutes, and when drilling fluid is completely lost, the maximum leakage should be measured by opening the pump;

[0070] According to the drilled lithology and the design treatment target layer, the drilling trajectory should be adjusted in time to ensure that the drilling is conducted along the designed layer or depth.

[0071] Water pressure test conditions: water pressure test before grouting in each grouting section, unit water absorption rate of whole hole pressure test ≯1Lu;

[0072] The purpose of water pressure test after grouting is to verify the grouting treatment effect to some extent by comparing the change of water absorption rate before and after grouting.

[0073] Grouting conditions: during the construction of three openings, except for the directional horizontal hole group Z1 boundary hole, if the leakage is >5m 3 / h, stop drilling and grout; if the leakage is ≤5m 3 / h, drill at most 100m for grouting;

[0074] During the grouting process, the water pressure test and grouting process should be recorded in detail; the specific gravity, pump capacity, pump pressure, and hole pressure of each tank of grout should be measured and recorded according to the format of the grouting report record table; the grouting amount data, water pressure test data before and after grouting should be collected in time, and the grouting effect should be analyzed to provide a basis for the next construction.

[0075] Grouting materials and grout proportioning:

[0076] Cement: P.O 42.5 ordinary portland cement should be used, which should meet the national GB175-2007 standard, and cement affected by moisture and clumping or expired cement should not be used;

[0077] Grout proportioning: after water pressure test before grouting, cement single liquid grout is used for grouting in the injection layer, the specific gravity of the grout is adjusted between 1.2 and 1.6 from small to large, and the early stage is mainly filled with thin grout, and the specific gravity of the grout is gradually adjusted according to the hole pressure in the middle and late stages;

[0078] Grouting end criteria:

[0079] The final pressure of grouting is designed to be the orifice pressure, which is greater than 10 MPa in principle, the final volume of grouting is less than 60 L / min, and the stable time is greater than 30 min. The pressure greater than 10 MPa is 1.5 times of the hydrostatic pressure, and the grouting pressure is different at different depths. The final volume of grouting is less than 60 L / min, and the stable time is greater than 30 min.

[0080] The standard of full-hole unit water absorption rate: after the branch hole grouting, the full-hole water pressure test is carried out, and the unit water absorption rate q is not greater than 0.01 L / min·m·m, that is, 1 Lu, which means that the hole reaches the grouting end standard.

[0081] Grouting and hole sealing: when the final hole grouting reaches the end standard, the specific gravity of the slurry is appropriately increased to realize the purpose of continuous grouting and hole sealing. The grouting project installs a grouting recorder and provides online monitoring services for the mine. During the grouting period, the mine can monitor the grouting flow, pressure, and density at any time.

[0082] Drilling fluid consumption analysis:

[0083] The drilling fluid consumption of the Z1-8 hole of the Z1 three-opening section of the directional horizontal hole group Z1 is located between 1.20-7.20 m 3 / h, which is greater than 5 m 3 / h, which is abnormal consumption; according to the consumption analysis, the hole initially uncovers the collapse column at 1460-1493 m; after grouting, the consumption of the remaining branch holes during drilling is located in the range of 0-4.20 m 3 / h, which is less than 5 m 3 / h, which is normal consumption; the consumption of the formula hole during drilling is located in the range of 0-0.40 m 3 / h, which is less than 5 m 3 / h, which is normal consumption; it is believed that after the grouting treatment of the Z1 hole group, the subsequent construction drilling uncovers the collapse column formation, and after the grouting transformation, the column is basically filled and blocked, and the grouting treatment effect of the collapse column is remarkable.

[0084] Cuttings logging analysis:

[0085] When drilling Z1-8 reached the collapse column section, cuttings logging showed large pieces of rock cuttings and flaking, indicating abrupt changes in lithology and lithological mixing, consistent with typical characteristics of a collapse column fracture zone. After the initial exposure, grouting was implemented, with a total of 9232 tons of cement injected. Subsequent branch holes Z1-3, Z1-5, Z1-7, Z1-Mobile 1, Z1-Mobile 2, and Z1-Mobile 3 all showed dense filling of cement fragments in the exposed section, indicating that the grout effectively bridged the fractures and formed a water-blocking barrier. Holes Z1-1, Z1-2, Z1-4, Z1-6, and Z1-9 failed to capture characteristic rock fragments of the collapse column throughout the entire process, confirming the irregularity of the column boundary. Combined with the borehole trajectory and plan profile analysis, the original design boundary of the collapse column shifted 60m to the southeast, measuring 99.4m in length and 82.6m in width on the fourth ash layer, resulting in the exposure depth of the Z1 borehole group being concentrated in the range of 1444-1569m. The adjusted exposure range of the J1 follower borehole group shows that the column extends significantly vertically, with its top located below coal seam 82.

[0086] Drilling logging analysis:

[0087] The drilling efficiency of borehole Z1-8 (1460-1557m) fluctuates, indicating poor formation integrity and classifying it as an anomalous formation. Similarly, the drilling efficiency of borehole Z1-7 (1460-1490m) suddenly decreases, indicating poor formation integrity and classifying it as an anomalous formation. The drilling efficiency of borehole Z1-3 (1440-1533m) also fluctuates, indicating poor formation integrity and classifying it as an anomalous formation. The drilling efficiency of borehole J1-3 (1040-1070m) also fluctuates, indicating poor formation integrity and classifying it as an anomalous formation.

[0088] Gamma logging analysis:

[0089] The gamma-ray durium (WDG) values ​​in boreholes Z1-8 (1460-1557m) are significantly higher than those in the limestone formation, with noticeable fluctuations, indirectly indicating a stratigraphic anomaly in this section. Similarly, the WDG values ​​in boreholes Z1-7 (1460-1493m) are also significantly higher than those in the limestone formation, with noticeable fluctuations, indirectly indicating a stratigraphic anomaly in this section. The WDG values ​​in boreholes Z1-3 (1451-1477m and 1503-1508m) show significant fluctuations, indirectly indicating a stratigraphic anomaly in this section. The WDG values ​​in boreholes J1-5 (1125-1181m) are also significantly higher than those in the limestone formation, with noticeable fluctuations, indirectly indicating a stratigraphic anomaly in this section. Finally, the WDG values ​​in boreholes J1-2 (1136-1196m) are also significantly higher than those in the limestone formation, with noticeable fluctuations, indirectly indicating a stratigraphic anomaly in this section.

[0090] Through multi-level exploration using horizontal directional drilling, combined with multi-dimensional information analysis including cuttings logging, drilling fluid loss, drilling time analysis, natural gamma ray, and grouting volume, the development morphology of the collapse column has been basically determined. Compared with the analysis position before exploration, the center of the collapse column has shifted to the southeast direction by about 60m. The adjusted directional borehole group J1 revealed that the column extends significantly vertically, with the top located below coal seam 82.

[0091] Ground long observation hole water level analysis: before treatment monitoring data shows that the first two ash aquifer and the middle group limestone and ordovician limestone show unified water level characteristics;

[0092] After the implementation of grouting engineering, the target layer hydraulic system shows significant differentiation:

[0093] 2020-T1 hole belongs to the upper group limestone long observation hole of Taiyuan group, and still maintains 2.0 MPa orifice pressure after stopping grouting and pressure relief stabilization, compared with 2020-T3 hole ordovician limestone-12.0 m water level elevation and 2022-Taiyuan limestone observation 2 hole belongs to the middle group limestone long observation hole of Taiyuan group 0.22 MPa orifice pressure, forming obvious hydraulic gradient, confirming that the hydraulic connection channel between the first two ash and the middle group limestone and ordovician limestone has been effectively blocked;

[0094] During the construction of subsequent directional formula hole group J1, the pressure of 2020-T1 hole stabilized at 1.1 MPa, and the water level of 2020-T3 hole remained at-7.8 m elevation, and the interlayer hydraulic system did not appear abnormal fluctuation, further verifying that the first two ash to ordovician limestone system and the third opening layer did not form new water channel between the first five ash, which marked the success of the target layer isolation of subsidence column grouting plugging engineering.

[0095] 2022-Taiyuan limestone observation 2 hole is between five to eight ash, showing a slow rising trend during grouting, and slowly declining after grouting. Since five to eight ash and third opening layer belong to the middle group limestone karst fissure development zone, this phenomenon reflects the existence of weak permeable contact interface or local limited fracture network between the two, which is a small amount of hydraulic response, which is consistent with the normal dynamic characteristics of regional limestone aquifer system, and has essential difference with the abnormal water channel of the target layer of treatment engineering; The overall monitoring data shows that the project has successfully blocked the main water inrush risk channel in the influence area of subsidence column, and the reconstruction of aquifer system has reached the expected treatment goal.

[0096] The permeability of directional horizontal hole group Z1 after grouting is 0.0062-0.0089 Lu, which shows that after treatment, the formation is transformed into an aquifuge, and the effect of subsidence column treatment is remarkable; The permeability of directional formula hole group J1 is 0.0079-0.0098 Lu, which further verifies the obvious effect of previous treatment.

[0097] The final technical effect is:

[0098] The engineering accumulatively grouts 24 times, accumulatively injects cement 15001.65t, and the average unit grouting quantity of three openings is 2.561t / m; through statistics, the low-pressure stage injects cement 10872.5t, accounting for 72.5%, the medium-pressure stage injects cement 3135.5t, accounting for 20.9%, and the high-pressure stage injects cement 993.65t, accounting for 6.6%. The low-pressure grouting quantity is large, indicating that the fracture development in the treatment area is large and there is a large fracture channel, and the actual collapse column is exposed; the medium-pressure and high-pressure stage grouting quantity is small, indicating that the collapse column is basically filled and solidified after treatment, and there are only a few small seepage fracture channels; with the increase of the engineering grouting quantity, the initial pressure of the subsequent branch hole before grouting is significantly improved than that of the already constructed branch hole, indicating that the engineering grouting reconstruction effect is good.

[0099] In summary, the directional horizontal hole group Z1 is constructed in the order of lower, upper and middle, the ground direction is constructed from the branch hole of the hole group J1 to different directions, and the range of the collapse column is found out; through the cuttings logging, drilling fluid, observation of water level in the hole before grouting and dynamic change of nearby Taiyuan and Ordovician limestone water level, it is concluded that the collapse column treatment has shown significant effect through comprehensive analysis.

[0100] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A method for subsidence column exploration and treatment based on ground directional drilling, characterized in that, It comprises the following steps: S1, through high-density three-dimensional seismic exploration, the position of the collapse column developed in the exploration area is explored, and the physical parameters of the collapse column from top to bottom in 72 coal, 82 coal, Taiyuan group, and each layer of Ordovician limestone are explored; S2, through drilling hydrological long observation holes in three groups of strata of limestone in the upper group of Taiyuan group, limestone in the middle group of Taiyuan group, and Ordovician limestone, and carrying out pumping test, corresponding hydrogeological parameters are obtained, and the hydraulic connection between each group of aquifers in the collapse column is determined; S3, selecting lower, upper and middle treatment modes, and grouting in the first to fifth limestone sections in the collapse column body; Among them, the development boundary of the collapse column is taken as the treatment range on the plane of the directional horizontal hole, the directional horizontal hole group Z1 is arranged in the treatment range, the directional horizontal hole group Z1 comprises 9 treatment branch holes and 3 mobile branch holes; The 9 treatment branch holes are respectively Z1-1 hole, Z1-2 hole, Z1-3 hole, Z1-4 hole, Z1-5 hole, Z1-6 hole, Z1-7 hole, Z1-8 hole and Z1-9 hole, and the 3 mobile branch holes are respectively Z1-mobile 1 hole, Z1-mobile 2 hole and Z1-mobile 3 hole; Among them, Z1-1 hole, Z1-2 hole, Z1-3 hole, Z1-4 hole and Z1-5 hole are horizontal exploration and treatment holes, Z1-6 hole and Z1-7 hole are upper sealing holes and are above the horizontal exploration and treatment holes, Z1-8 hole and Z1-9 hole are lower sealing holes and are below the horizontal exploration and treatment holes, and Z1-mobile 1 hole, Z1-mobile 2 hole and Z1-mobile 3 hole are supplementary reinforcement holes; S4, the hole for treatment further comprises a ground directional from hole, and the ground directional from hole is used for supplementary grouting and reinforcement of the upper column body of the collapse column; Among them, the development boundary of the collapse column is taken as the treatment range on the plane of the directional from hole, the directional from hole group J1 is arranged, and the directional from hole group J1 comprises 6 treatment branch holes and 2 mobile branch holes; The 6 treatment branch holes are respectively J1-1 hole, J1-2 hole, J1-3 hole, J1-4 hole, J1-5 hole and J1-6 hole, and the 2 mobile branch holes are respectively J1-mobile 1 hole and J1-mobile 2 hole; Among them, J1-1 hole, J1-2 hole, J1-3 hole, J1-4 hole, J1-5 hole and J1-6 hole are exploration and treatment holes, and J1-mobile 1 hole and J1-mobile 2 hole are supplementary reinforcement holes.

2. The method for subsidence column exploration and treatment based on ground directional drilling according to claim 1, characterized in that, For step S3, specifically, it comprises the following steps: S31, the development boundary of the collapse column is found out, Z1-1 hole, Z1-2 hole, Z1-3 hole, Z1-4 hole and Z1-5 hole are drilled along the four limestone layers, wherein Z1-1 hole and Z1-2 hole are drilled along the edge of the fracture development belt, the collapse column boundary is determined through the changes of rock debris, drilling time and drilling fluid consumption in the drilling process, if a large amount of drilling fluid is lost or the water pressure test is lost in the drilling process, the hole is sealed directly at this time, 20-30m is further expanded to explore the suspected collapse column boundary, and the collapse column boundary is determined repeatedly until the drilling enters the normal stratum. S32, after the boundary is found, firstly, Z1-8 hole and Z1-9 hole are drilled at 20-30m below the four ash in the profile, the drilling trajectory is drilled in the five ash layer before entering the front of the collapse column until the final hole position, the hole plane spacing is 40-80m, the position below the collapse column cutting position is grouted; Secondly, Z1-6 hole and Z1-7 hole are drilled along the four ash upward in the profile, the drilling trajectory is drilled in the five ash layer before entering the front of the collapse column until the final hole position, the plane hole spacing is 40-80m, the position above the collapse column cutting position is grouted; Finally, Z1-3 hole, Z1-4 hole and Z1-5 hole which are located in the middle position of Z1-1 hole and Z1-2 hole are used to grout the middle position of the collapse column cutting position; S33, Z1-motor 1 hole, Z1-motor 2 hole and Z1-motor 3 hole are used to supplement the reinforcement of the collapse column according to the exploration and treatment situation.

3. The method according to claim 1, wherein, For step S4, specifically, it includes: S41, the exploration and treatment holes J1-1 hole, J1-2 hole, J1-3 hole, J1-4 hole, J1-5 hole and J1-6 hole pass through 72 coal seam and 82 coal seam in turn and drill into the first to fourth ash layer; Among them, the directional from hole group J1 opens the bottom in the 72 coal seam roof, and the final hole is in the fourth ash layer, the final hole spacing is 40m, the change of rock debris, drilling time and drilling fluid consumption during drilling process determines the grouting effect of the collapse column, if a large amount of drilling fluid loss occurs during drilling or the water pressure test pressure is less than or equal to 10MPa, the collapse column is supplemented and grouted; S42, J1-motor 1 hole and J1-motor 2 hole are used to supplement the reinforcement of the collapse column according to the exploration and treatment situation.

4. The method for subsidence column exploration and treatment based on ground directional drilling according to claim 1, characterized in that, The J1-1 hole, J1-2 hole, J1-3 hole, J1-4 hole, J1-5 hole and J1-6 hole of the directional from hole group J1 are arranged in increasing order of 60° azimuth angle from the drilling center.

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