Ground directional drilling goaf passing leaking stoppage method

Abstract

The invention discloses a ground directional drilling goaf passing leaking stoppage method which comprises the steps that hole data of a goaf are obtained, and the hole data comprise the hole depth and the crack width; when the width of the crack is larger than 5 mm, a foundation plugging material is adopted for conducting foundation plugging on the hole of the goaf, and the foundation plugging material is an inert material and cement paste; judging whether basic plugging fails or not to obtain a first judgment result; if the first judgment result shows that the basic plugging fails, a flexible plugging material is adopted for conducting medium-term plugging on the holes in the goaf, and the flexible plugging material is a material formed by mixing hemp fiber, sawdust, soybeans and water. According to foundation plugging, a large channel is filled through particle bridging, a primary plugging layer is formed after cement paste is solidified, the flexible material can adapt to trace deformation of surrounding rock through deformation filling, and micro cracks of a foundation layer are plugged. Through graded gradient filling, the leaking stoppage effect can be greatly improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of coal mine safety, in particular to the field of coal mining and geological disaster control. BACKGROUND

[0002] Goaf is a "cave" produced by human mining of coal under the ground. Due to the strong concealment of underground goaf, poor regularity of spatial distribution characteristics, and difficulty in predicting the collapse of goaf roof, drilling accidents such as drill pipe sticking are prone to occur when drilling through goaf. Moreover, due to the full loss of drilling fluid, drilling control is greatly disturbed, and even drilling accidents occur. SUMMARY

[0003] The purpose of the present application is to provide a ground directional drilling through goaf plugging method for improving plugging efficiency.

[0004] To achieve the above purpose, the present application provides the following scheme: A ground directional drilling through goaf plugging method, the method comprising: Obtaining hole data of the goaf, the hole data comprising hole depth and crack width; When the crack width is greater than 5mm, a basic plugging material is used to plug the hole of the goaf, the basic plugging material being inert material and cement slurry; Judging whether the basic plugging is invalid, obtaining a first judgment result; If the first judgment result indicates that the basic plugging is invalid, a flexible plugging material is used to plug the hole of the goaf, the flexible plugging material being a mixture of hemp fiber, sawdust, soybeans and water.

[0005] In one or more embodiments, the basic plugging of the hole of the goaf with the basic plugging material specifically comprises: Determining a plugging area according to the hole data; Filling inert material into the hole of the goaf, wherein the filling amount of the inert material is 1.2-1.5 times the plugging area; Injecting cement slurry at a set rate, and monitoring the orifice pressure every 2 hours to ensure that the orifice pressure drop is ≤0.2MPa.

[0006] In one or more embodiments, the set rate is: an initial rate of 50-100L / min, which decreases to 30-50L / min when the orifice pressure rises to 1.5MPa, and the final pressure stabilizes at 2.0-2.5MPa.

[0007] In one or more embodiments, the base plugging of the cavity of the goaf with the base plugging material further comprises: real-time acquisition of the loss amount collected by the sensor; when the loss amount is greater than 15 m 3 / h, injecting inert material and cement slurry in 3-5 batches, each batch accounting for 20-30% of the total estimated amount, with an interval of 2-4 h.

[0008] In one or more embodiments, the base plugging of the cavity of the goaf with the base plugging material further comprises: when the loss amount is greater than 10 m 3 / h and the crack width is greater than 10 mm, increasing the amount of inert material to 1.5 times.

[0009] In one or more embodiments, determining whether the base plugging is ineffective comprises: real-time acquisition of the loss amount collected by the sensor; if the loss amount is greater than 10 m 3 / h and the pressure in the hole does not rise, it is determined that the plugging is ineffective.

[0010] In one or more embodiments, the mid-term plugging of the cavity of the goaf with the flexible plugging material comprises: preparing the flexible plugging material according to the design ratio; injecting the flexible plugging material into the cavity of the goaf, wherein the injection rate is controlled at 30 L / min and the orifice pressure is controlled at 1.8 MPa.

[0011] In one or more embodiments, the mid-term plugging of the cavity of the goaf with the flexible plugging material further comprises: real-time acquisition of the loss amount collected by the sensor; when the loss amount is greater than 12 m 3 / h, increasing the proportion of soybeans in the flexible inert material and re-preparing the flexible plugging material.

[0012] In one or more embodiments, the method further comprises: determining whether the mid-term plugging is ineffective, obtaining a second determination result; if the second determination result indicates that the mid-term plugging is ineffective, performing late-term plugging of the cavity of the goaf with a rigid plugging material, the rigid plugging material being a mixture of cement slurry and water glass, wherein the injection rate of the rigid inert material is controlled at 40 L / min and the orifice pressure is controlled at 2.4 MPa.

[0013] In one or more embodiments, the method further comprises: determining whether the late plugging is plugged failure, to obtain a third determination result; If the third determination result indicates that the late plugging is plugged failure, the rigid plugging material is used to perform late plugging on the hole of the goaf again until the plugging is successful.

[0014] In one or more embodiments, the base plugging material is a mixed material of rock debris with a particle size of 0.5-2 mm and cement slurry with a water-cement ratio of 1:1.2-1:1.5; The flexible plugging material is a mixed material of hemp fiber with a length of 5-10 mm, sawdust with a particle size of 1-3 mm and yellow beans with a particle size of 2-4 mm at a ratio of 1:2:1; The rigid plugging material is a double liquid slurry of cement slurry with a water-cement ratio of 1:1.0-1:1.2 and water glass with a modulus of 2.4-2.8 at a volume ratio of 3:1-5:1.

[0015] According to the specific embodiments of the present application, the following technical effects are disclosed: For cracks greater than 5 mm, first, the base plugging is adopted, if the plugging effect is good, the plugging is stopped, if the plugging effect is not good, the medium-term plugging is continued, that is, the flexible plugging material is used to perform medium-term reinforcement. The base plugging fills the large channel through "particle bridging", and the cement slurry forms a preliminary plugging layer after solidification, which can reduce the leakage from >30 m 3 / h to 15-20 m 3 / h. The flexible material can adapt to the micro deformation of the surrounding rock through "deformation filling", and plug the micro cracks of the base layer, avoiding the cracking of the plugging layer due to the displacement of the surrounding rock, and the leakage can be reduced to 5-10 m 3 / h. After the above hierarchical gradient filling, the plugging effect can be greatly improved.

[0016] It should be understood that the content described in the summary section is not intended to limit the key or important features of the embodiments of the present disclosure, nor to limit the scope of the present disclosure. Other features of the present disclosure will become apparent through the following description. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0018] Figure 1 Design a profile design drawing for directional drilling of the main hole in the damaged area of the goaf; Figure 2A flowchart of one embodiment of the ground directional drilling through the goaf plugging method provided by the present application is shown in the figure; Figure 3 A flowchart of another embodiment of the ground directional drilling through the goaf plugging method provided by the present application is shown in the figure. DETAILED DESCRIPTION

[0019] 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. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] In addition, the term "and / or" in this paper is only to describe the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can represent three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents an "or" relationship between the front and rear associated objects.

[0021] The goaf formed after the exploitation of coal resources often presents the typical characteristics of "multi-layer communication, dynamic development of fissures, and poor stability of surrounding rock". When directional drilling passes through these areas, three difficulties are often encountered in actual operation: first, the poor adaptability of the leakage channel, the existing technology relies on a single rigid material (such as pure cement slurry) or a single flexible material (such as pure sawdust), which cannot simultaneously cope with the composite leakage form of "macro leakage channel (diameter 5-20mm) + micro fissure (diameter 1-5mm)", resulting in a "large channel that cannot be blocked, and small fissures that cannot be tightly sealed"; second, the low controllability of the grouting process, the traditional method uses the "one-time full injection" process, which does not control the grouting pressure, rate, and setting time - high pressure can easily induce new fissures, and low pressure cannot penetrate the slurry; finally, the monitoring feedback is lagging, only monitoring a single parameter of the hole pressure or leakage amount, lacking visual detection means in the well, resulting in a "strong blindness" of the plugging scheme. In actual application, the plugging success rate is less than 60%, the single plugging time is more than 48 hours, the material loss rate is more than 60%, and the drill pipe sticking rate is more than 30%. These pain points seriously restrict the construction efficiency and safety, and it is urgent to build a "material-technology-monitoring" coordinated technical system.

[0022] In view of the above problems, the present application proposes a directional drilling plugging construction method based on gradient material hierarchical plugging, step-by-step grouting precise pressure control, and dynamic monitoring real-time feedback. Through the above optimization, the target realizes a plugging success rate of ≥95%, a material consumption reduction of ≥70%, and an in-hole accident rate of ≤5%, thereby ensuring the smooth implementation of directional drilling in the goaf.

[0023] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0024] Figure 2 A flowchart of an embodiment of the ground directional drilling through goaf plugging method provided by the present application is shown in FIG. 1. As shown in FIG. 1, the method comprises the following steps. Figure 2 Step 210: obtaining hole data of the goaf, wherein the hole data comprises hole depth and crack width; Step 220: when the crack width is greater than 5 mm, using a basic plugging material to perform basic plugging on the hole of the goaf, wherein the basic plugging material is inert material and cement slurry; the inert material can comprise inert granular material, fibrous material or sheet material, specifically, such as rock debris, fiber and mica sheet, etc.

[0025] Step 230: judging whether the basic plugging is invalid, to obtain a first judgment result; Step 240: if the first judgment result indicates that the basic plugging is invalid, using a flexible plugging material to perform interim plugging on the hole of the goaf, wherein the flexible plugging material is a mixture of hemp fiber, sawdust, soybeans and water.

[0026] In this embodiment, for cracks greater than 5 mm, first, basic plugging is performed, i.e., inert material and cement slurry are used for first plugging, if the plugging effect is good, the plugging is stopped, and the drill bit directly drills. If the plugging effect is not good, interim plugging is continued, i.e., flexible plugging material is used for interim reinforcement. The basic plugging fills large channels through "granular bridging", and the cement slurry forms a preliminary plugging layer after solidification, which can reduce the leakage from > 30 m 3 / h to 15-20 m 3 / h. The flexible material can adapt to the micro deformation of the surrounding rock through "deformation filling", and plug the micro cracks of the basic layer, avoiding cracking of the plugging layer due to displacement of the surrounding rock, and the leakage can be reduced to 5-10 m 3 / h. The above-mentioned gradient filling can greatly improve the plugging effect.

[0027] In one or more embodiments, the basic plugging material is a mixture of rock debris with a particle size of 0.5-2 mm, a composite plugging agent with an added amount of 3-5% of the mass of the cement slurry, and cement slurry with a water-cement ratio of 1:1.2-1:1.5.

[0028] This combination fills large channels through "granular bridging", the composite plugging agent forms a colloidal plugging gap, and the cement slurry forms a preliminary plugging layer after solidification, which can reduce the leakage from > 30 m 3 / h to 15-20 m 3 ​ / h.

[0029] The composite plugging agent can include: (1) Inert particle material: walnut shell powder, peanut shell powder, quartz sand, calcium carbonate particles, etc., which can be graded according to the leakage channel to quickly fill and form a preliminary plugging; (2) Fiber material: lignin fiber, polypropylene fiber, etc., which bridge to form a "fiber net" to intercept particles, strengthen the stability of the skeleton, and adapt to the fractured leakage layer; (3) Sheet material: mica sheet, graphite sheet, talc powder, etc., which fill the gaps to form a dense interface and reduce the permeability of the plugging layer.

[0030] In one or more embodiments, the base plugging material can be used to base plug the holes in the goaf, which can specifically include: determining the plugging area according to the hole data; filling inert material into the holes in the goaf, wherein the filling amount of the inert material is 1.2-1.5 times the plugging area; injecting cement slurry at a set rate, and monitoring the orifice pressure every 2 hours to ensure that the orifice pressure drop is ≤0.2 MPa.

[0031] In this embodiment, the inert material can be rock debris with a particle size of 0.5-2 mm.

[0032] The plugging area can be calculated according to the hole depth and crack width, or can be determined empirically according to historical data.

[0033] When grouting, the orifice pressure is detected in real time, and the grouting rate is adjusted according to the orifice pressure, which is beneficial to realize effective plugging and reduce slurry loss.

[0034] In one or more embodiments, on the basis of the above embodiments, the set rate can be: an initial rate of 50-100 L / min, which is reduced to 30-50 L / min when the orifice pressure rises to 1.5 MPa, and the final pressure is stabilized at 2.0-2.5 MPa.

[0035] In this embodiment, the cement slurry is injected at a high rate in the initial stage, and the grouting rate is reduced after the effective plugging is formed, i.e. the orifice pressure starts to rise. The grouting rate is adjusted in real time according to the orifice pressure, so as to adjust in real time according to the grouting effect.

[0036] In one or more embodiments, the base plugging material used to base plug the holes in the goaf can also include: real-time acquisition of the leakage amount collected by the sensor; when the leakage amount is greater than 15 m3 When the leakage is greater than 15 m

[0037] In this embodiment, the leakage is also monitored on the basis of the detection of the hole pressure. When the leakage is greater than 15 m 3 / h, it indicates that the leakage is relatively large, and the plugging effect is not good. The inert material and the cement slurry can be injected in batches, and the next grouting is performed after a fixed time interval and after the condensation of the previous slurry. In this way, the plugging effect is better. The set value 15 m 3 / h is an empirical value obtained through multiple tests, and can be adjusted according to actual conditions.

[0038] In one or more embodiments, the basic plugging of the hole of the goaf by the basic plugging material further includes: When the leakage is greater than 10 m 3 / h and the crack width is greater than 10 mm, the amount of inert material is increased to 1.5 times.

[0039] In this embodiment, if the leakage does not decrease and the crack width of the hole is too large, i.e., greater than 10 mm, it indicates that the hole is too large and is not easy to be plugged and formed. Therefore, it is suggested to increase the amount of inert material, for example, to 1.5 times of the planned amount. The types of the inert material can be operated according to the description of embodiment one, which is not repeated here.

[0040] In one or more embodiments, determining whether the basic plugging is failed can specifically include: Real-time acquisition of the hole pressure and the leakage; If the leakage is greater than 10 m 3 / h and the hole pressure does not increase, it is determined that the plugging is failed.

[0041] In this embodiment, two monitoring data, the hole pressure and the leakage, are collected simultaneously, and whether the plugging is successful is comprehensively determined according to the two indexes. If the leakage is greater than 10 m 3 / h and the hole pressure does not increase, it indicates that the plugging material is not fixed and is continuously lost. Therefore, it can be determined that the hole is not successfully plugged.

[0042] In one or more embodiments, the intermediate plugging of the hole of the goaf by the flexible plugging material specifically includes: The flexible plugging material is prepared according to a designed proportion; The flexible plugging material is injected into the hole of the goaf, wherein the grouting rate is controlled to be 30 L / min, and the hole pressure is controlled to be 1.8 MPa.

[0043] In this embodiment, when the medium-term plugging is carried out, first, the flexible plugging material is prepared, the hemp fiber with a length of 5-10 mm, sawdust with a particle size of 1-3 mm and soybeans with a particle size of 2-4 mm are mixed at a ratio of 1:2:1, and then injected into the hole of the goaf. The flexible plugging material can adapt to the micro deformation of the surrounding rock through "deformation filling", plug the micro cracks of the basic layer, avoid the cracking of the plugging layer due to the displacement of the surrounding rock, and the leakage amount can be reduced to 5-10 m 3 / h.

[0044] It should be noted that the medium-term plugging also needs to control the grouting speed, at this time the speed is not easy to be fast, and it also needs to be adjusted in real time according to the orifice pressure. Among them, the orifice pressure is controlled at 1.8 MPa, which is more appropriate.

[0045] In one or more embodiments, the medium-term plugging of the hole of the goaf by the flexible plugging material further comprises: real-time acquisition of the leakage amount collected by the sensor; when the leakage amount is greater than 12 m 3 / h, increase the proportion of soybeans in the flexible inert material, that is, mix hemp fiber, sawdust and soybeans at a ratio of 1:2:2, and re-prepare the flexible plugging material.

[0046] In this embodiment, if the leakage amount is too large during the medium-term plugging, it is considered that the plugging gap of the early-stage basic plugging is too large and no effective plugging is formed, so the amount of soybeans is increased and the particle size is increased.

[0047] In one or more embodiments, the medium-term plugging of the hole of the goaf by the flexible plugging material further comprises: when the leakage amount is 5-10 m 3 / h and the crack width is 5-10 mm, the ratio of hemp fiber, sawdust and soybeans in the flexible plugging material is adjusted to 1:2:2. This is done to increase the particle size of the flexible plugging material and increase the probability of wall hanging, which is beneficial to form plugging and improve the plugging effect.

[0048] In one or more embodiments, the method can further comprise: judging whether the medium-term plugging is plugging failure, to obtain a second judgment result; if the second judgment result indicates that the medium-term plugging is plugging failure, using a rigid plugging material for late-stage plugging of the hole of the goaf, the rigid plugging material being a material mixed by cement slurry and water glass, wherein the grouting rate of the rigid inert material is controlled at 40 L / min, and the orifice pressure is controlled at 2.4 MPa.

[0049] In this embodiment, if the medium-term plugging is carried out, it is still unsuccessful (the leakage amount is greater than 5 m 3 / h), and can also be carried out late plugging, that is, using rigid plugging material for perfusion, at which time pressure and speed control are also needed. The late strengthening plugging forms a rigid stable layer, using cement slurry (water-cement ratio 1:1.0-1:1.2) + water glass (modulus 2.4-2.8), volume ratio 3:1-5:1. The double-liquid slurry initial setting time is 5-15 min, and the 24h compressive strength is ≥15MPa, forming a high-strength rigid layer outside the flexible reinforcing layer, and finally controlling the loss to be <5m 3 / h.

[0050] In one or more embodiments, the method can further comprise: judging whether the late plugging is plugging failure, to obtain a third judgment result; if the third judgment result indicates that the late plugging is plugging failure, using rigid plugging material to re-plug the hole of the goaf for late plugging until plugging is successful.

[0051] After the three stages of early basic plugging, medium-term flexible plugging and late rigid plugging, most of the empty space will be successfully plugged. However, for extreme cases, if the plugging effect is still not good, late plugging can be performed again to consolidate the plugging effect. This step is only a remedial measure and is rarely encountered.

[0052] Figure 3 Another flowchart of the ground directional drilling through the goaf plugging method according to another embodiment of the application is provided. As Figure 3 described, comprising the following steps: 1. Start plugging operation; 2. First, carry out early basic plugging (crack width is greater than 5mm), and the plugging material is: rock debris + composite plugging agent + cement slurry.

[0053] 3. Effect evaluation is carried out on the early basic plugging, if the effect is good (loss is less than 5m 3 / h), directly stop plugging and carry out normal drilling. If the effect is not good, medium-term flexible reinforcement is carried out.

[0054] 4. Medium-term flexible reinforcement, and the material selected is: hemp + sawdust + soybeans.

[0055] 5. Effect evaluation is carried out on the medium-term flexible reinforcement, if the effect is good (loss is less than 5m 3 / h), directly stop plugging and carry out normal drilling. If the effect is not good, late strengthening plugging is carried out.

[0056] 6. Late strengthening plugging, and the material used is: cement slurry + water glass double-liquid slurry.

[0057] 7. Effect evaluation is performed on the late-stage reinforced plugging, if the effect is good (the leakage is less than 5 m 3 / h), the plugging is directly stopped, and normal drilling is performed. If the effect is not good, the late-stage reinforced plugging is continuously performed until the effect is good (the leakage is less than 5 m 3 / h).

[0058] In the embodiment two, only the plugging process is described, and the specific plugging details can be referred to the specific description of other embodiments, which will not be described here.

[0059] The three core invention points are cooperated in the application, and the specific details of the invention points are as follows: (1) Gradient plugging material selection and staged plugging.

[0060] According to the logic of "macro channel filling → micro crack reinforcement → rigid layer strengthening", the materials are selected in three stages. The early-stage basic plugging is aimed at the macro leakage channel with a diameter of 5-20 mm, and uses the combination of rock debris (particle size 0.5-2 mm, proportion 40-50%) + composite plugging agent + cement slurry (water-cement ratio 1:1.5). This combination fills the large channel through "particle bridging", the composite plugging agent forms a colloidal gap, and the cement slurry forms a preliminary plugging layer after solidification, which can reduce the leakage from >30 m 3 / h to 15-20 m 3 / h. The medium-term flexible reinforcement processes the micro cracks with a diameter of 1-5 mm, and the material is hemp fiber (length 5-10 mm, proportion 25%) + sawdust (particle size 1-3 mm, proportion 50%) + soybean (particle size 2-4 mm, proportion 25%), which is mixed with water in a mass ratio of 1:2 to form a paste. The flexible material can adapt to the micro deformation of the surrounding rock through "deformation filling" to plug the micro cracks of the basic layer, avoid the cracking of the plugging layer due to the displacement of the surrounding rock, and reduce the leakage to 5-10 m 3 / h. The late-stage reinforced plugging forms a rigid stable layer, and uses cement slurry (water-cement ratio 1:1.0-1:1.2) + water glass (modulus 2.4-2.8) with a volume ratio of 3:1-5:1. The initial setting time of the double liquid slurry is 5-15 min, and the 24h compressive strength is ≥15 MPa. The high-strength rigid layer is formed outside the flexible reinforcement layer, and finally the leakage is controlled to be <5 m 3 / h.

[0061] (2) Step-by-step grouting and pressure control adopts a three-step process of "filling-grouting-setting" combined with an intermittent adjustment mechanism. In the first step of filling, inert material (particle size 1 / 3-1 / 2 of the leakage channel diameter) is added at a rate of ≤50 kg / min, with a filling volume of 1.2-1.5 times the estimated leakage space volume. After filling, the amount of slurry returned must be ≥80% of the injected volume. In the second step of grouting, the initial rate is 50-100 L / min (slurry diffusion stage). After the orifice pressure rises to 1.5 MPa, it decreases to 30-50 L / min (slurry penetration stage), and finally stabilizes at 2.0-2.5 MPa (strictly prohibited from exceeding 2.5 MPa). In the third step of setting, cement slurry sets for ≥24 hours, and double-liquid slurry sets for ≥2 hours. During this period, the orifice pressure is monitored every 2 hours to ensure a pressure drop ≤0.2 MPa. For leakage >15 m³... 3 For complex channels with a flow rate of / h, grouting is carried out in 3-5 batches, with each batch using 20-30% of the total estimated amount, with an interval of 2-4 hours. During this period, the morphology of the sealing layer is observed using downhole television. If leakage is still significant, the proportion of water glass is increased in the next batch.

[0062] (3) A dynamic monitoring and feedback system is constructed using a dual-dimensional feedback mechanism of "multi-parameter monitoring + visual detection". Borehole multi-parameter monitoring instrument (accuracy: water level ±0.1m, leakage ±0.5m) 3 Data ( / h, orifice pressure ±0.05MPa) is recorded every 5 minutes. If the leakage is >10m 3 If the pressure does not increase at a rate of / h, it is considered a "seal-closing failure" and refilling is required. High-definition downhole television (resolution ≥720P, detection depth ≥300m, positioning accuracy ±0.5m) is used once before each stage of sealing (to identify the location of leakage, fracture width / direction) and once after curing (to verify the integrity of the sealing layer), providing a basis for adjusting the plan.

[0063] This invention offers significant advantages: the success rate of leak sealing is increased from <60% in existing technologies to ≥95%, and the leakage rate is reduced from >50m³ in the initial stage. 3 / h stabilized and decreased to <5m 3 / h; the amount of cement used per application decreased by 70%, the cost of flexible materials was only 1 / 5 of that of chemical sealants, and the overall material cost decreased by 65%; the average time for a single sealant application was reduced from 48 hours to 19.2 hours (a reduction of 60%), effectively avoiding project delays caused by repeated sealant applications.

[0064] Taking the directional drilling and plugging project of the Gequan Mine No. 8 well as an example, the implementation process of this invention is explained in detail (the well traverses the goaf of the No. 2 coal seam and the lower No. 2 coal seam (e.g.) Figure 1 As shown), the initial leakage rate is 50m. 3 / h, there is a risk of the drill string getting stuck). I. Preliminary Survey Data Preparation: 2 Coal mining area (hole depth 110-120m, fissure width 10-15mm), 2 lower coal mining area (hole depth 180-190m, fissure width 8-12mm); equipment and materials: drilling multi-parameter monitor, high-definition downhole television; rock debris (0.5-2mm), composite plugging agent, cement, water glass (modulus 2.6), hemp, sawdust, soybeans.

[0065] II. Implementation steps Step 1: Pre-basis plugging (1) Filling: Artificial orifice into rock debris 8 tons (rate 40 kg / min), filling capacity is 1.3 times the estimated lost space (12m 3 ).

[0066] (2) Grouting: Inject composite plugging agent + cement slurry (water-cement ratio 1:1.3, 5 tons), initial rate 80L / min, pressure rises to 1.5MPa, then drops to 40L / min, the final pressure is stabilized at 2.2MPa.

[0067] (3) Waiting for condensation: After 24h monitoring, the orifice pressure drops by 0.1MPa (qualified), downhole television shows that the 110-120m area macro channel is basically filled, and the leakage is reduced to 18m 3 / h.

[0068] Step 2: Mid-term flexible reinforcement (1) Preparation of materials: hemp (0.75 tons) + sawdust (1.5 tons) + soybeans (0.75 tons), mixed with 3 tons of water into paste.

[0069] (2) Intermittent grouting: Injected in 2 batches (1.5 tons each, interval 3h), grouting rate 30L / min, pressure control at 1.8MPa.

[0070] (3) Verification: After waiting for 2h, the leakage is reduced to 9m 3 / h, downhole television shows that the 180-190m area micro fissure is basically plugged.

[0071] Step 3: Late-stage reinforcement plugging (1) Configuration of double liquid slurry: Cement slurry (water-cement ratio 1:1.1, 3 tons) + water glass (0.75 tons, volume ratio 4:1).

[0072] (2) Grouting: Rate 40L / min, pressure stabilized at 2.4MPa, grouting volume 4 tons.

[0073] (3) Waiting for condensation and verification: After waiting for 4h, the leakage is reduced to 3m 3 / h.

[0074] Step 4: Dynamic adjustment and accident prevention and control (whole process) monitoring: Pressure, loss, step 2 grouting loss temporarily increased to 12m 3 / h, by increasing the proportion of soybeans (adjust to 1:2:2), 1h later decreased to 8m 3 / h.

[0075] III. Implementation effect engineering index: A total of 4 times of plugging (including 1 time of intermittent adjustment), the final loss is stable at 3m 3 / h, successfully completed the second casing down to 240.33m.

[0076] Economic indicators: the lowest single cement consumption is 6 tons, which is reduced by 78.6% compared with the initial construction (28 tons), and the total material cost is saved by 126,000 yuan.

[0077] Efficiency index: single plugging time is shortened from 52 hours to 20 hours, which is shortened by 61.5%, and the construction period is advanced by 8 days.

[0078] In the specification, each embodiment is described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts of each embodiment can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the method part.

[0079] In this paper, specific examples are used to illustrate the principles and implementation methods of the present application. The above embodiment is only used to help understand the method and core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation and application range will be changed. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A method for sealing leaks through goaf areas using directional drilling on the ground, characterized in that, The method includes: Acquire borehole data in the goaf area, wherein the borehole data includes borehole depth and crack width; When the crack width is greater than 5 mm, the holes in the goaf are sealed with basic sealing material, which is an inert material and cement grout. Determine whether the basic sealing has failed to seal, and obtain the first determination result; If the first judgment result indicates that the basic sealing has failed, a flexible sealing material is used to temporarily seal the holes in the goaf. The flexible sealing material is a mixture of hemp fiber, sawdust, soybeans and water.

2. The method as described in claim 1, characterized in that, The basic sealing of the holes in the goaf using basic sealing materials specifically includes: The sealing area is determined based on the hole data; Inert material is filled into the cavities in the goaf, wherein the amount of inert material is 1.2-1.5 times the sealing area; Inject cement grout at the set rate and monitor the orifice pressure every 2 hours to ensure that the orifice pressure drop is ≤0.2MPa.

3. The method as described in claim 2, characterized in that, The set rate is as follows: the initial rate is 50-100 L / min, and when the orifice pressure rises to 1.5 MPa, it drops to 30-50 L / min, and finally the pressure stabilizes at 2.0-2.5 MPa.

4. The method as described in claim 2, characterized in that, The basic sealing of the holes in the goaf using basic sealing materials also includes: Real-time acquisition of leakage data collected by sensors; When the leakage is greater than 15m 3 When the volume is / h, inert material and cement slurry are injected in 3-5 batches, with each batch accounting for 20-30% of the total estimated volume, and the interval is 2-4 hours.

5. The method as described in claim 2, characterized in that, The basic sealing of the holes in the goaf using basic sealing materials also includes: When the leakage amount is >10m 3 When the crack width is greater than 10 mm, the amount of inert material is increased to 1.5 times.

6. The method as described in claim 1, characterized in that, Determining whether the basic sealing has failed includes: Real-time acquisition of orifice pressure and leakage; If the leakage amount is >10m 3 If the pressure inside the hole does not increase at / h, it is determined that the sealing has failed.

7. The method as described in claim 1, characterized in that, The intermediate sealing of the holes in the goaf using flexible sealing materials specifically includes: Mix the flexible sealing material according to the design ratio; The flexible sealing material is injected into the holes in the goaf, wherein the grouting rate is controlled at 30L / min and the orifice pressure is controlled at 1.8MPa.

8. The method as described in claim 7, characterized in that, The intermediate sealing of the holes in the goaf using flexible sealing materials also includes: Real-time acquisition of leakage data collected by sensors; When the leakage is greater than 12m 3 When / h, increase the proportion of soybeans in the flexible inert material and readjust the flexible sealing material.

9. The method as described in claim 1, characterized in that, The method further includes: Determine whether the intermediate-term sealing has failed to seal, and obtain a second determination result; If the second judgment result indicates that the intermediate sealing has failed, a rigid sealing material is used to seal the holes in the goaf. The rigid sealing material is a mixture of cement slurry and water glass. The grouting rate of the rigid inert material is controlled at 40 L / min, and the orifice pressure is controlled at 2.4 MPa.

10. The method as described in claim 9, characterized in that, The method further includes: Determine whether the subsequent sealing has failed to seal, and obtain a third determination result; If the third judgment result indicates that the subsequent sealing has failed, rigid sealing material is used to seal the holes in the goaf again until the sealing is successful.

11. The method as described in claim 8, characterized in that, The basic sealing material is a mixture of rock chips with a particle size of 0.5-2mm and cement slurry with a water-cement ratio of 1:1.2-1:1.5; The flexible sealing material is a mixture of hemp fiber with a length of 5-10 mm, sawdust with a particle size of 1-3 mm, and soybeans with a particle size of 2-4 mm in a ratio of 1:2:

1. The rigid sealing material is a two-component slurry made of cement grout with a water-cement ratio of 1:1.0-1:1.2 and water glass with a modulus of 2.4-2.8 mixed in a volume ratio of 3:1-5:1.

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