A method for pre-extracting coal seam gas by drilling large holes with a raise boring machine

Abstract

The present invention provides a method for pre-extraction of coal seam gas by large-diameter drilling using a raise boring rig. First, a number of candidate drilling positions are divided within the construction area according to the construction characteristics of the raise boring rig and the requirements for large-diameter drilling, and binary decision variables are defined to characterize the drilling selection situation and functional type. Secondly, based on the drilling influence radius and two-dimensional coordinates, positive and negative pressure collaborative pressure field constraints are introduced to ensure that the actual pressure field in the construction area meets the preset target pressure distribution. Then, an integer programming optimization model with the goal of minimizing the total number of boreholes is established, and construction safety constraints, spatial spacing constraints, and geometric layout constraints are combined to ensure construction safety and a reasonable distribution of positive and negative pressure boreholes. Finally, by solving the optimization model, the optimal drilling layout plan is obtained, and the decision variable values ​​of each candidate position are output, which solves the problems of the large number of boreholes, long construction period, and insufficient positive and negative pressure collaborative effect in the coal seam gas pre-extraction process in the prior art.

Description

Technical Field

[0001] The invention relates to a method for pre-extracting coal seam gas by drilling large holes in a raise boring machine, belonging to the field of gas extraction methods. Background Art

[0002] During coal seam gas pre-extraction, raise boring rigs, as highly efficient drilling equipment, possess the ability to drill large-diameter holes during raise boring construction, creating larger fracture fields within the coal seam and thus improving coal seam gas extraction efficiency. Existing technologies often employ traditional drilling rigs for multi-hole arrangements, often resulting in numerous holes, long construction cycles, and insufficient synergy between positive and negative pressures. In particular, in the application scenario of raise boring rigs drilling large-diameter holes for coal seam gas pre-extraction, the question of how to optimize the hole arrangement, reduce the number of holes, and shorten the construction cycle while maintaining the advantages of large-diameter drilling has become a pressing technical challenge. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to design a method for pre-extracting coal seam gas by drilling large holes with a raise boring machine, so as to overcome the shortcomings of the prior art.

[0004] The technical solution of the present invention is to provide a method for pre-extracting coal seam gas by drilling large holes with a raise boring machine, comprising the following steps:

[0005] S1. Within the planned construction area, several potential candidate drilling locations are divided according to the construction characteristics of the raise boring rig and the large-diameter requirement. Each location is represented by an index i.

[0006] S2. Define binary decision variables x i If a large-diameter hole is selected for construction at candidate location i, then x i =1; otherwise x i =0;

[0007] S3. Define variable y i Indicates the functional type of the drilling at candidate location i, where y i =1 means positive pressure function is used, y i =0 means using negative pressure function;

[0008] S4. For each candidate position i, record its two-dimensional coordinates and pre-estimate the influence radius R of each borehole based on the large-diameter construction characteristics of the raise boring machine. i ;

[0009] S5. constructing an objective function to minimize the total number of selected drill holes;

[0010] S6, according to the influence radius R of each drilling i The positive and negative pressure collaborative pressure field constraints are introduced into the two-dimensional coordinates, requiring that the actual pressure field formed in the entire construction area is not lower than the target pressure distribution Ptarget (r);

[0011] S7. Arrange the objective function and all constraints into a standard integer programming model;

[0012] S8. Obtain the optimal solution by performing a local search using an integer programming solver;

[0013] S9. Output the decision variable value x of each candidate position i and y i .

[0014] Furthermore, the objective function is:

[0015]

[0016] Where n represents the total number of candidate drilling locations pre-divided in the construction area, r∈R represents all sampling points in the construction area, r represents the sampling point, R represents the construction area, P target (r) represents the ideal pressure set at the sampling point r, Indicates the pressure contribution of the selected borehole to the sampling point r, g i (y i ,r) indicates the function type y i The pressure contribution function of the borehole at the candidate location i to the sampling point r and the trade-off coefficient λ are determined based on the field test data and simulation results.

[0017] Furthermore, step S6 also includes: introducing a spatial distance safety constraint, according to the requirements of the raise boring machine construction and large-diameter drilling operation, ensuring that the Euclidean distance d(i, j) between any two selected drilling positions i and j is not less than the minimum construction spacing L min .

[0018] Furthermore, the step S6 further includes: introducing a geometric constraint, stipulating that for each candidate position i selected as a positive pressure hole, at least k negative pressure holes must be configured within a predetermined area of ​​the position i.

[0019] Furthermore, the step S6 also includes: introducing construction equipment and safety constraints, and limiting the candidate locations to meet the operating range of the raise boring machine and the safety technical requirements of large-diameter drilling construction.

[0020] The beneficial effects of the present invention are: compared with the prior art,

[0021] 1) By using candidate location partitioning and an integer programming model, the present invention can minimize the number of drill holes while ensuring construction results. This not only reduces construction investment and drilling costs, but also shortens the construction period and improves overall operational efficiency.

[0022] 2) By simultaneously introducing positive and negative pressure functions and rationally configuring the functional types of each drilling hole, the present invention creates a pressure field that meets the desired objectives throughout the construction area. The synergistic effect between the positive and negative pressure holes helps to more effectively form a large fracture field, thereby improving the extraction effect of coal seam gas;

[0023] 3) The invention incorporates spatial distance safety constraints to ensure that the minimum construction spacing requirements are met between any two boreholes, effectively preventing equipment collisions and mutual interference. The introduction of geometric constraints and construction equipment and safety constraints ensures that the drilling layout complies with the operating range of the raise boring rig and the safety and technical requirements for large-diameter drilling construction;

[0024] 4) This invention utilizes integer programming and local search methods to quickly find optimal or near-optimal solutions under complex conditions with multiple constraints and objectives, providing a reliable basis for decision-making during on-site construction. The penalty term for pressure distribution deviation in the objective function ensures that the optimization solution is more aligned with actual on-site needs.

[0025] 5) The present invention not only improves the efficiency of coal seam gas extraction, but also reduces safety risks and economic costs by reducing the number of drill holes, optimizing the drilling function configuration and shortening the construction period, thereby improving the technical level and economic benefits of the entire gas pre-extraction project. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Flowchart of the present invention. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be described in further detail below with reference to the accompanying drawings.

[0028] refer to Figure 1 A method for pre-extracting coal seam gas by drilling large-diameter holes using a raise boring machine comprises the following steps:

[0029] S1. Within the planned construction area, several potential candidate drilling locations are divided according to the construction characteristics of the raise boring rig and the large-diameter requirement. Each location is represented by an index i.

[0030] S2. Define binary decision variables x i If a large-diameter hole is selected for construction at candidate location i, then x i =1; otherwise x i =0;

[0031] S3. Define variable y i Indicates the functional type of the drilling at candidate location i, where y i =1 means using positive pressure (pre-extraction gas pre-cracking) function, y i=0 means using negative pressure function (gas extraction);

[0032] S4. For each candidate position i, record its two-dimensional coordinates and pre-estimate the influence radius R of each borehole based on the large-diameter construction characteristics of the raise boring machine. i ;

[0033] S5. Construct an objective function to minimize the total number of selected drill holes:

[0034]

[0035] Where n represents the total number of candidate drilling locations pre-divided in the construction area, r∈R represents all sampling points in the construction area, r represents the sampling point, R represents the construction area, P target (r) represents the ideal pressure set at the sampling point r, Indicates the pressure contribution of the selected borehole to the sampling point r, g i (y i ,r) indicates the function type y i The pressure contribution function of the borehole at the candidate location i to the sampling point r and the trade-off coefficient λ are determined based on the field test data and simulation results.

[0036] S6, according to the influence radius R of each drilling i The positive and negative pressure collaborative pressure field constraints are introduced in the two-dimensional coordinates to describe the impact of each large-diameter borehole on the surrounding coal seam pressure field, requiring that the actual pressure field formed in the entire construction area is not lower than the target pressure distribution P target (r); Introduce spatial distance safety constraints, according to the requirements of raise boring machine construction and large-diameter drilling operations, ensure that the Euclidean distance d(i, j) between any two selected drilling positions i and j is not less than the minimum construction spacing L min To achieve a synergistic effect of positive and negative pressures similar to a five-flowered layout, geometric constraints are introduced, stipulating that for each candidate location i selected as a positive pressure hole, at least k negative pressure holes must be configured within the predetermined area of ​​location i. Furthermore, step S6 also includes introducing construction equipment and safety constraints, limiting the candidate locations to meet the operating range of the raise boring rig and the safety and technical requirements for large-diameter drilling construction, ensuring that the model solution is feasible in practical applications.

[0037] S7. Arrange the objective function and all constraints into a standard integer programming model;

[0038] Limit the candidate locations to meet the operating range of the raise boring machine and the safety and technical requirements for large-diameter drilling construction;

[0039] S8. Obtain the optimal solution by performing a local search using an integer programming solver;

[0040] S9. Output the decision variable value x of each candidate positioni and y i .

[0041] Working principle:

[0042] This invention achieves global optimization of the drilling layout by constructing a mathematical model for drilling layout and employing integer programming discrete optimization. While ensuring the synergistic effect of positive and negative pressures and the formation of a large-aperture fracture field, this approach minimizes the number of drill holes and dynamically optimizes construction scheduling, thereby improving pre-extraction gas efficiency and reducing construction costs.

[0043] Any details not described in detail herein are well known to those skilled in the art. Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention, and such modifications or equivalents should be encompassed by the claims of the present invention.

Claims

1. A method for pre-extracting coal seam gas by drilling large holes with a raise boring machine, characterized in that: The following steps are involved: S1. Within the planned construction area, several potential candidate drilling locations are divided according to the construction characteristics of the raise boring rig and the large-diameter requirement. Each location is represented by an index i. S2. Define binary decision variables x i If a large-diameter hole is selected for construction at candidate location i, then x i =1; otherwise x i =0; S3. Define variable y i Indicates the functional type of the drilling at candidate location i, where y i =1 means positive pressure function is used, y i =0 means using negative pressure function; S4. For each candidate position i, record its two-dimensional coordinates and pre-estimate the influence radius R of each borehole based on the large-diameter construction characteristics of the raise boring machine. i ; S5. constructing an objective function to minimize the total number of selected drill holes; S6, according to the influence radius R of each drilling i The positive and negative pressure collaborative pressure field constraints are introduced into the two-dimensional coordinates, requiring that the actual pressure field formed in the entire construction area is not lower than the target pressure distribution P target (r); S7. Arrange the objective function and all constraints into a standard integer programming model; S8. Obtain the optimal solution by performing a local search using an integer programming solver; S9. Output the decision variable value x of each candidate position i and y i .

2. The method for pre-extraction of coal seam gas by large-diameter drilling using a raise boring machine according to claim 1, characterized in that: The objective function is: Where n represents the total number of candidate drilling locations pre-divided in the construction area, r∈R represents all sampling points in the construction area, r represents the sampling point, R represents the construction area, P target (r) represents the ideal pressure set at the sampling point r, Indicates the pressure contribution of the selected borehole to the sampling point r, g i (y i ,r) indicates the function type y i The pressure contribution function of the borehole at the candidate location i to the sampling point r and the trade-off coefficient λ are determined based on the field test data and simulation results.

3. The method for pre-extraction of coal seam gas by large-diameter drilling using a raise boring machine according to claim 1, characterized in that: The step S6 also includes: introducing a spatial distance safety constraint, according to the requirements of the raise boring machine construction and large-diameter drilling operation, ensuring that the Euclidean distance d(i, j) between any two selected drilling positions i and j is not less than the minimum construction spacing L min .

4. The method for pre-extraction of coal seam gas by large-diameter drilling using a raise boring machine according to claim 1, characterized in that: The step S6 further includes: introducing a geometric constraint, stipulating that for each candidate position i selected as a positive pressure hole, at least k negative pressure holes must be configured within a predetermined area of ​​the position i.

5. The method for pre-extraction of coal seam gas by large-diameter drilling using a raise boring machine according to claim 1, characterized in that: The step S6 further includes: introducing construction equipment and safety constraints, and limiting candidate locations to meet the operating range of the raise boring machine and safety technical requirements for large-diameter drilling construction.

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