Search

CN-122006173-A - Injection detection separated coal fire crack identification plugging method and plugging system

CN122006173ACN 122006173 ACN122006173 ACN 122006173ACN-122006173-A

Abstract

The invention discloses a method and a system for identifying and plugging cracks of coal fire separated by injection detection, which relate to the field of coal field drilling and coal field fire area treatment, wherein the plugging method forms a drilling network for the construction of the coal fire area, selecting observation holes to perform combined electro-magnetic scanning, acquiring data vectors before and after the tracer medium is injected, reconstructing three-dimensional conductivity and permeability distribution of underground cracks, acquiring three-dimensional spatial spread of the cracks, and determining grouting amount of the tracer plugging material; the system integrates heat radiation drilling, crack identification, plugging and control depth, and completes the whole flow of high-temperature pore forming, trace injection, electromagnetic scanning, inversion imaging, targeted grouting and effect verification. The invention realizes the double-parameter joint inversion of conductivity and magnetic conductivity, solves the problems that natural geological anomalies and crack channels cannot be distinguished by single electric method/magnetic method detection, the inversion results are false and abnormal, and the like, realizes true three-dimensional and high-resolution stereo imaging of crack space distribution and connectivity, and provides a high-precision target for targeted grouting.

Inventors

  • XIN HAIHUI
  • BAI GUANGYU
  • CAO KAI
  • ZHANG LONG
  • YANG YI
  • ZHANG PENGCHENG
  • HUANG YINGMING
  • LI KUIKUI

Assignees

  • 中国矿业大学
  • 鄂尔多斯应用技术学院

Dates

Publication Date
20260512
Application Date
20260415

Claims (10)

  1. 1. The method for identifying and plugging the coal fire cracks by injection detection separation is characterized by comprising the following steps of: S1, constructing a coal fire area to form a drilling network comprising injection holes and observation holes; Selecting a drilling hole positioned at the center of a crack development expected area as an injection hole, and taking at least 2 adjacent drilling holes on the periphery of the drilling hole as observation holes; S2, selecting at least one observation hole to perform combined electro-magnetic scanning, wherein the combined electro-magnetic scanning is well-ground combined electro-magnetic scanning and/or cross-hole combined electro-magnetic scanning, and acquiring a background field multi-physical quantity data vector comprising potential data and magnetic field data before injection ; Continuously injecting trace medium with obvious difference of conductivity and magnetic conductivity into the injection hole, moving trace medium along the fracture network under the action of pressure, and making combined electro-magnetic scanning again to obtain multi-physical data vector of excitation field ; S3-1, defining a double-parameter model of the underground medium Constructing an inversion objective function comprising a data fitting term and a model regularization term ; S3-2, solving the nonlinear inversion problem of the step S3-1 by adopting a Gaussian-Newton iteration method, reconstructing three-dimensional conductivity and permeability distribution of the underground fracture, and calculating final model parameter change distribution ; As a final model of the output it is, Is an initial background model, the Directly characterizing the three-dimensional spatial spread of the crack filled with the tracer medium; S4, determining grouting amount of the tracer plugging material based on three-dimensional space spread of the cracks, injecting the tracer plugging material preset with conductive and magnetic components into a plugging target point, and verifying grouting plugging effect.
  2. 2. The method for identifying and plugging the coal fire cracks by means of separation by injection and detection according to claim 1, wherein the method comprises the following steps of, In step S3-1, an inversion objective function comprising a data fitting term and a model regularization term is constructed : Wherein, the For the parameter variation distribution of each grid unit in the final underground three-dimensional space, the non-zero area represents the crack filled with the tracer medium; The data weighting matrix is used for normalizing the signal-to-noise ratio difference of different observed data; The magnetic field partial derivative submatrix is formed by combining and splicing a potential partial derivative submatrix of a high-density electrical method and a magnetic field partial derivative submatrix of a magnetic measurement in a well; The regularization factor is used for adjusting weight balance between the data fitting degree and the model smoothness; A model roughness matrix; A square representing the euclidean norm of the vector for quantizing the magnitude of the residual; For time-shifted differential observation data vectors, the calculation formula is: ; in step S3-2, the method specifically comprises the following loop iteration steps: S3-2-1, initializing iteration, namely enabling the iteration times to be equal to An initial background model As an initial model of inversion, setting a residual error convergence threshold and the maximum iteration times; S3-2-2, forward response and joint sensitivity jacobian matrix dynamic update based on current first Model for multiple iterations Numerical simulation is carried out by utilizing a multi-physical-field positive algorithm, and theoretical response of the current model is calculated Simultaneously recalculate the current joint sensitivity jacobian matrix ; S3-2-3, constructing a correction regularization normal equation set; introducing model corrections To construct a normal equation set containing the double differential residual term: Wherein, the Is the first Model correction of the next iteration; is the first Current joint sensitivity jacobian matrix for a secondary iteration Is used to determine the transposed matrix of (a), Weighting matrices for data Is a transposed matrix of (a); theoretical response for the initial background model; s3-2-4, solving a model correction amount: The normal equation set in the step S3-2-3 is solved by using the conjugate gradient least square method iteration to obtain the model correction quantity of the current iteration step ; S3-2-5, updating model parameters: The obtained model correction amount Superimposed to the current model, update subsurface medium parameters: Wherein, the For the next parameter of the subsurface medium, Is the current underground medium parameter; For iterative search steps, dynamically determined by a line search algorithm to ensure inversion of the objective function Is in monotonous descending trend; s3-2-6, judging convergence conditions and outputting results: calculating the norm of the current iteration data residual error and model correction If it is less than the set convergence threshold, or the number of iterations Triggering a stop condition when the set maximum number of times is reached, ending the iteration loop, and outputting a final underground medium double-parameter model If the stopping condition is not satisfied, then Returning to execute the step S3-2-2 to enter the next cycle; S3-2-7, extracting abnormal crack spread: From the final model of the output Calculating final model parameter variation distribution 。
  3. 3. The method for identifying and plugging the coal fire cracks by means of separation by injection and detection according to claim 2, wherein the method comprises the following steps of, In the step S3-2-1, an initial background model is provided The construction process comprises the steps of carrying out data vector analysis on a plurality of physical quantities of a background field As input, combining the geological drilling histogram of the region and the priori information of the electrical/magnetic logging curve, utilizing a conventional smooth inversion algorithm to establish three-dimensional initial physical distribution grids of the underground space, endowing each grid with initial conductivity and magnetic conductivity values, and forming an initial background model ; In the step S3-2-2, the theoretical response of the current model Current joint sensitivity jacobian matrix The construction process comprises the steps of respectively establishing a control equation of a direct-current stable electric field and a static magnetic field in a three-dimensional medium and taking the control equation as a physical forward operator; for high density electrical methods, poisson's equation describing the stable electric field distribution is established: Wherein, the In the case of a divergence operator, For the purpose of the gradient operator, In order to be of electrical conductivity, Is of potential and conductivity And potential of All change along with the three-dimensional space coordinate; the point power source is supplied with a current density, In order for the intensity of the current to be high, As a dirac function, Position vector for point power supply; A position vector for an arbitrary point in three-dimensional space; For borehole magnetic measurements, a static magnetic field integral equation describing the abnormal field of magnetization is established: Wherein, the Is a vector of the spatial magnetic anomaly, Is vacuum magnetic permeability; Is magnetization intensity; Is the position vector of the observation point With the position vector of the source point of the underground field The difference is that the module length is ; Is a unit vector of the number of units, ; Integrating the volume in a three-dimensional space where the underground abnormal body is located; The poisson equation and the static magnetic field integral equation for stabilizing the electric field distribution are discretely solved by a finite element or finite volume method to obtain the theoretical response of the current model And extracting the partial derivative matrix to update the current joint sensitivity jacobian matrix The partial derivative matrix is formed by splicing a potential partial derivative submatrix of the current high-density electrical method and a magnetic field partial derivative submatrix of the current well magnetic survey.
  4. 4. The method for identifying and plugging the coal fire cracks by means of separation by injection and detection according to claim 1, wherein the method comprises the following steps of, In the step S4, the grouting amount of the tracer plugging material The calculation formula of (2) is as follows: Wherein, the Is the slurry diffusion loss coefficient; Space inversion of the volume of the crack for effective filling of the tracer medium; to image the total number of three-dimensional grids, For the index number of the grid cell, ; Is the first Monomeric element geometric volumes of the individual grids; is the first Equivalent crack porosity obtained by converting the grids based on an Azithro formula; is the first Inversion conductivity variation of the individual grids; Conductivity for the tracer medium; Is a cementation index.
  5. 5. The method for identifying and plugging the coal fire cracks by means of separation by injection and detection according to claim 1, wherein the method comprises the following steps of, The step S4 specifically includes the following steps: S4-1, grouting and plugging, namely determining a key crack channel as a grouting and plugging target point according to the three-dimensional space spread of the cracks obtained in the step S3, and injecting a tracer and plugging material preset with conductive and magnetic components into the plugging target point; S4-2, scanning and inverting again, namely repeating the step S2 after the tracer plugging material is solidified, obtaining a multi-physical-quantity data vector comprising potential data and magnetic field data after plugging, and inverting and imaging; S4-3, checking the blocking effectiveness: comparing and judging the latest inversion imaging result with the actual grouting engineering parameters: If the double physical field abnormality which is consistent with the electromagnetic response characteristic of the tracer plugging material is detected in the original crack target three-dimensional area, the inversion volume is obtained through a voxel integral formula And the actual recorded grouting amount If the error is within the set allowable threshold range, judging that grouting plugging is effective; Judging invalid and abnormal processing, wherein if any condition occurs that no obvious electromagnetic abnormality is detected in the target three-dimensional area, the electromagnetic abnormality area seriously deviates from a set plugging target point, and the volume is inverted And judging that the grouting plugging is invalid if the ratio of the actual grouting amount is smaller than 0.7.
  6. 6. A fire crack identification plugging system for a separated coal by injection, for implementing the fire crack identification plugging method for a separated coal by injection of claim 1, comprising: The drilling unit is used for drilling a drilling network comprising an injection hole and an observation hole for the construction of the coal fire area; The crack identification unit is provided with a pouring component for pouring a tracer medium into the pouring agent hole, an electro-magnetic detection component for carrying out combined electro-magnetic scanning to obtain potential data and magnetic field data, and an analysis component for constructing a model to obtain three-dimensional space distribution of cracks and verifying plugging effectiveness; The plugging unit is provided with a plugging part for pouring tracer plugging materials into the drilling hole; The control unit is used for controlling actions of the units, namely controlling the drilling unit to drill a coal fire area to form a drilling network, controlling the electric-magnetic detection component to acquire a background field electromagnetic response data vector before injection after the drilling network is completed, controlling the injection component to continuously inject a tracer medium into one or more injection holes, controlling the electric-magnetic detection component to acquire an excitation field electromagnetic response data vector during or after injection, and controlling the plugging unit to inject the tracer plugging material into the drilling hole after an analysis component construction model acquires a three-dimensional spatial spread of a crack.
  7. 7. The separated coal fire crack identification plugging system according to claim 6, wherein, The system also comprises a shallow treatment unit which is configured to be used for constructing an oxygen-isolated ecological matrix on the ground surface after the fire in the fire area of the coal field is deeply extinguished; The ecological matrix is formed by mixing 15-25 parts by weight of straw-based hydrogel microspheres, 30-40 parts by weight of red mud-biochar composite particles, 20-30 parts by weight of decomposed coal gangue powder and 2-5 parts by weight of arbuscular mycorrhizal fungi embedded slow release agent; the ecological matrix is mixed with water and then spread on the surface of the fire area, and the thickness is more than or equal to 20cm.
  8. 8. The separated coal fire crack identification plugging system according to claim 6, wherein, The drilling unit is provided with a heat dissipation drill rod, and the heat dissipation drill rod comprises: The drill rod (10) and the drill bit (20) are connected with each other, a closed heat dissipation cavity (31) is arranged in the drill bit (20), and the heat dissipation cavity (31) is filled with phase change materials; A cooling component, which is provided with an energy storage box (40) positioned in the drill rod (10) and at least one condensing box (32) positioned at the inner side of the energy storage box (40); The energy storage box (40) is fixedly arranged, liquid cryogenic working medium is stored in the energy storage box (40), the condensing box (32) is connected with the driving component (60) and driven to move radially, under the action of the driving component (60), when the temperature in the drill rod (10) exceeds a first temperature threshold value, the condensing box (32) moves to a contact position with the energy storage box (40) radially, when the temperature in the drill rod (10) falls below a second temperature threshold value, the condensing box (32) moves to a separation position with the energy storage box (40) radially, or when the rotating speed of the drill rod (10) exceeds a first rotating speed threshold value, the condensing box (32) moves to a contact position with the energy storage box (40) radially, and when the rotating speed of the drill rod (10) falls below a second rotating speed threshold value, the first temperature threshold value is larger than the second temperature threshold value, and the first rotating speed threshold value is larger than the second rotating speed threshold value; The condensing box (32) and the radiating cavity (31) are respectively connected with the return pipe (34) through the evaporating pipe (33) to form a closed loop, so that the phase change material can be evaporated into the condensing box (32) from the radiating cavity (31) and then flows back into the radiating cavity (31).
  9. 9. The separated coal fire crack identification plugging system according to claim 8, wherein, The driving component (60) is provided with a supporting cylinder (62), a supporting rod (64) and a memory alloy piece (61); One end of the supporting rod (64) is movably positioned in the supporting cylinder (62) and is contacted with the elastic piece (63), and the other end of the supporting rod is fixedly connected with the condensing box (32); An elastic piece (63) is arranged in the supporting cylinder (62), the elastic piece (63) is respectively contacted with the inner wall of the supporting cylinder (62) and the supporting rod (64), under the action of the elastic piece (63), the supporting rod (64) bears the elastic force towards the axis of the drill rod (10), and under the action of centrifugal force, the supporting rod (64) moves to compress the elastic piece (63); The memory alloy piece (61) is close to the axis of the drill rod (10), one end of the memory alloy piece (61) is fixed, the other end of the memory alloy piece is fixedly connected with the supporting cylinder (62), the drill bit (20) is provided with the heat conducting fin (22), one end of the heat conducting fin (22) extends to be connected with the memory alloy piece (61), and when the temperature reaches a first temperature threshold value, the memory alloy piece (61) is heated to be elongated; Or: The drill bit (20) is provided with a temperature sensor, the end side of the drill rod (10) is provided with an angular velocity sensor for sensing the rotating speed of the drill rod (10), and the driving part (60) is a driving rod and is fixed in the drill rod (10); the temperature sensor, the angular velocity sensor and the lead of the driving rod are led out through the electric slip ring and then connected with the controller, and the controller controls the action of the driving rod.
  10. 10. The separated coal fire crack identification plugging system of claim 8, further comprising: the central tube (50) is hollow and is coaxially positioned inside the drill rod (10) and the drill bit (20); The drill rod (10) comprises an inner drill rod and an outer drill rod, and an annular cavity (13) is formed between the inner drill rod and the outer drill rod; the inner drill rod is provided with an auxiliary vent hole (11) communicated with the annular cavity (13), the lower end of the annular cavity (13) is provided with a main vent hole (12) communicated with the outside, and the upper end of the annular cavity is connected with a first high-pressure air source through a first rotary joint, wherein the main vent hole (12) is inclined, and the lower end of the main vent hole faces a drill bit (20); the energy storage box (40) is positioned in the inner drill rod, and the upper end of the energy storage box is provided with a pressure release valve (41) connected with the auxiliary vent hole (11); Wherein the cryogenic working medium is liquid nitrogen; One end of the central tube (50) positioned at the drill bit (20) is provided with a sealing head (21), and one end positioned at the drill rod (10) can be connected with a slag discharging box and a second high-pressure air source in a switching way through a second rotary joint; The end socket (21) is arranged to open the port of the central tube (50) when receiving pressure from bottom to top and close the port of the central tube (50) when receiving pressure from top to bottom; The controller controls the inlet pressure of the first high-pressure air source and the second high-pressure air source.

Description

Injection detection separated coal fire crack identification plugging method and plugging system Technical Field The invention relates to a coal field drilling technology, belongs to the field of coal field fire zone treatment, and in particular relates to a coal fire crack identification and plugging method and a plugging system for injection detection separation. Background Coal field fire (coal fire) is a very destructive geological disaster, has the characteristics of wide combustion range, long duration, large treatment difficulty and the like, and mainly adopts a treatment technical route combining stripping, water injection, drilling, grouting and covering at present, but has the following problems in practical application: 1. The drilling is a key link before implementing underground grouting, because of the characteristic of high temperature of fire in a coal field, such as the surface temperature of a shallow fire area is often higher than 200 ℃, when a drill rod drills, the local hot spot temperature generated by high-speed friction between a drill bit and a high-temperature rock stratum can exceed 500 ℃, and the high-temperature drilling environment directly causes 1) rapid degradation of the cutting tooth material of the drill bit, hardness reduction, increased abrasion, frequent replacement, low operation efficiency and high cost, 2) the high-temperature drill bit is an ignition source, the coal bodies around the drill hole are extremely easy to ignite, secondary disasters are caused, so that the treatment work is the best, and the traditional high-pressure water injection cooling mode is adopted, but a large amount of cold water invades the high-temperature rock stratum to rapidly change the physical and mechanical properties of the high-temperature rock stratum, so that serious safety accidents such as landslide and the like are extremely easy to be induced; 2. The invention discloses a mine fire and surface fire coexistence coal field fire zone shallow oxygen control choking treatment method, which is characterized in that filling filler is filled into a cavity zone through shallow treatment drill holes, pre-cooling a shallow high temperature zone of the fire zone, carrying out layered blocking on the shallow zone after cooling, and monitoring a synchronous fire zone. However, the plugging range of the scheme depends on the judgment of a shallow macroscopic temperature field, the crack network is not subjected to targeted imaging, the spatial distribution and the permeation path of hidden cracks cannot be identified, so that grouting is still blind, and accurate plugging of a key oxygen supply channel is difficult to realize; At present, geophysical technology, including an electric method, a magnetic method, an acoustic method and the like, is mainly adopted for detecting the cracks. The detection cracks are mainly applied to the researches of underground water exploitation, reservoir oil gas exploitation, geological exploration, hydrogeology, environmental monitoring and the like, but belong to passive detection, and lack of special detection thought for coal fire cracks, and the Chinese patent publication No. CN121409762A discloses a coal fire area crack active enhancement detection test system and method. However, the scheme is used for laboratory mechanism research and method verification, lacks a nonlinear characteristic fracture inversion method aiming at strong contrast abnormality of the tracer, is limited to small-scale coal rock test pieces, does not relate to engineering drilling operation in a real field high-temperature fire area environment, lacks a multi-element coupling design of 'on-site drilling-detection inversion-quantitative plugging-effect verification', and is difficult to support on-site 'probing-then-plugging-on-demand' engineering logic. Disclosure of Invention The invention aims to provide a coal fire crack identification and plugging method and a plugging system for grouting and detection separation, wherein the plugging method remarkably improves the identification precision and reliability of hidden cracks, realizes double-parameter joint inversion of conductivity and magnetic conductivity, can solve the problems that natural geological anomalies and crack channels cannot be distinguished by single electric method/magnetic method detection, has a plurality of false anomalies of inversion results and poor positioning precision, realizes true three-dimensional and high-resolution three-dimensional imaging of crack space spread and connectivity, and provides a high-precision target for targeted grouting. In order to achieve the purpose, the method for identifying and plugging the coal fire cracks by the injection detection separation specifically comprises the following steps: S1, constructing a coal fire area to form a drilling network comprising injection holes and observation holes; Selecting a drilling hole positioned at the center of a crack development expe