Method for pre-extracting coal seam gas during construction of large-aperture drill hole by raise boring machine

Abstract

The invention provides a method for pre-extracting coal seam gas during large-aperture drilling in raise boring machine construction, which comprises the following steps of: firstly, dividing a plurality of candidate drilling positions in a construction area according to construction characteristics and large-aperture drilling requirements of a raise boring machine, and defining binary decision variables to represent drilling selection conditions and function types; secondly, according to the drilling influence radius and the two-dimensional coordinate, positive and negative pressure cooperative pressure field constraint is introduced, and it is ensured that the actual pressure field in the construction area meets preset target pressure distribution; then, an integer programming optimization model with the aim of minimizing the total number of drill holes is established, and construction safety and reasonable distribution of positive and negative pressure drill holes are ensured in combination with construction safety constraints, spatial spacing constraints and geometric arrangement constraints. And finally, an optimal drill hole layout scheme is obtained by solving the optimization model, decision variable values of all candidate positions are output, and the problems that in the coal seam gas pre-drainage process in the prior art, the number of drill holes is large, the construction period is long, and the positive and negative pressure cooperation effect is insufficient are solved.

Description

Technical Field

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

[0002] In the process of pre-extraction of coal seam gas, the raise boring machine, as a high-efficiency drilling equipment, has the ability to drill large-diameter holes in the raise boring construction, and can form a larger fracture field in the coal seam, thereby improving the coal seam gas extraction effect. In the existing technology, traditional drilling rigs are often used for multi-hole arrangement, which often has problems such as a large number of drilling holes, a long construction period, and insufficient positive and negative pressure synergy. Especially in the application scenario of the raise boring machine to construct large-diameter drilling holes for pre-extraction of coal seam gas, how to optimize the drilling arrangement, reduce the number of drilling holes, and shorten the construction period while ensuring the advantages of large-diameter drilling has become a technical problem that needs to be solved urgently. 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 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 a large-diameter hole using a raise boring machine, comprising the following steps:

[0005] S1. In the predetermined construction area, according to the construction characteristics of the raise boring machine and the large-aperture requirements, several potential candidate drilling locations are divided, and 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 represents the functional type of the drilling hole at candidate location i, where y i =1 means positive pressure function is adopted, y i =0 means negative pressure function is adopted;

[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 drilling holes;

[0010] S6. According to the influence radius R of each drilling hole i The positive and negative pressure coordinated 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, organize the objective function and all constraints into a standard integer programming model;

[0012] S8. Perform local search to obtain the optimal solution using integer programming solver;

[0013] S9. Output the decision variable value x of each candidate position i and 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 sampling point r, represents 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 position i to the sampling point r, and the trade-off coefficient λ, whose value is determined according to the field test data and simulation results.

[0017] Furthermore, step S6 also includes: introducing a spatial distance safety constraint, according to the operation requirements of the raise boring machine construction and large-diameter drilling, 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 also 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 in a predetermined area of ​​the position i.

[0019] Furthermore, the step S6 also includes: introducing construction equipment and safety constraints, and limiting the candidate positions 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) The present invention adopts candidate location division and integer programming model to reduce the number of drilling holes as much as possible while ensuring the construction effect. This not only reduces the construction investment and drilling costs, but also shortens the construction period and improves the overall operation efficiency;

[0022] 2) The present invention simultaneously introduces positive pressure and negative pressure functions, and through the reasonable configuration of each drilling function type, the entire construction area forms a pressure field that meets the expected goal. The synergy 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 ensures that the minimum construction spacing requirements are met between any two boreholes by adding spatial distance safety constraints, effectively preventing equipment collision and mutual interference. The introduction of geometric constraints and construction equipment and safety constraints ensures that the drilling arrangement meets the operating range of the raise boring machine and the safety technical requirements for large-diameter drilling construction;

[0024] 4) The present invention uses integer programming and local search methods to solve the problem, which can quickly find the optimal or approximate optimal solution under complex conditions of multiple constraints and multiple objectives, providing a reliable decision-making basis for on-site construction. The penalty term for pressure distribution deviation in the objective function makes the optimization solution closer to the actual needs of the site;

[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 It is a flow chart 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 further described in detail below with reference to the accompanying drawings of this specification.

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

[0029] S1. In the predetermined construction area, according to the construction characteristics of the raise boring machine and the large-aperture requirements, several potential candidate drilling locations are divided, and 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 represents the functional type of the drilling hole at candidate location i, where y i =1 means the positive pressure (pre-extraction gas pre-cracking) function is adopted, y i=0 means the negative pressure function (gas extraction) is adopted;

[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 drilling 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 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 position i to the sampling point r, and the trade-off coefficient λ, whose value is determined according to the field test data and simulation results.

[0036] S6. According to the influence radius R of each drilling hole i The positive and negative pressure coordinated pressure field constraints are introduced into the two-dimensional coordinates to describe the influence 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 . In order to achieve the positive and negative pressure synergy effect similar to the five-flowered layout, geometric constraints are introduced to stipulate that for each candidate position i selected as a positive pressure hole, at least k negative pressure holes must be configured in the predetermined area of ​​position i. Furthermore, step S6 also includes: introducing construction equipment and safety constraints, limiting the candidate positions to meet the operating range of the raise boring machine and the safety technical requirements of large-diameter drilling construction, and ensuring that the model solution is feasible in practical applications.

[0037] S7, organize 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. Perform local search to obtain the optimal solution using integer programming solver;

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

[0041] Working principle:

[0042] The present invention achieves global optimization of the drilling arrangement scheme by constructing a mathematical model of drilling arrangement and using integer programming discrete optimization solution. Under the premise of ensuring the synergistic effect of positive and negative pressures and the formation of a large-aperture fracture field, the scheme minimizes the number of drilling holes and dynamically optimizes the construction scheduling, thereby improving the pre-extraction gas efficiency and reducing the construction cost.

[0043] The parts not described in detail in the present invention are all known technologies to those skilled in the art. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of 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. In the predetermined construction area, according to the construction characteristics of the raise boring machine and the large-aperture requirements, several potential candidate drilling locations are divided, and 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 represents the functional type of the drilling hole at candidate location i, where y i =1 means positive pressure function is adopted, y i =0 means negative pressure function is adopted; 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 drilling holes; S6. According to the influence radius R of each drilling hole i The positive and negative pressure coordinated 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, organize the objective function and all constraints into a standard integer programming model; S8. Perform local search to obtain the optimal solution using integer programming solver; S9. Output the decision variable value x of each candidate position i and i .

2. The method for pre-extracting coal seam gas by drilling large holes with 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 sampling point r, represents 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 position i to the sampling point r, and the trade-off coefficient λ, whose value is determined according to the field test data and simulation results.

3. The method for pre-extracting coal seam gas by drilling large holes with 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-extracting coal seam gas by drilling large holes with a raise boring machine according to claim 1, characterized in that: The step S6 also 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 in a predetermined area of ​​the position i.

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

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