CN-122021157-A - Construction parameter optimization method and device for roof water jet slotting fracturing

CN122021157ACN 122021157 ACN122021157 ACN 122021157ACN-122021157-A

Abstract

The disclosure relates to a construction parameter optimization method and device for roof water jet slotted fracturing. The method comprises the steps of obtaining a geometric model and a fluid-solid coupling model of drilling, slotting and fracturing, generating a plurality of groups of construction parameters for roof water jet slotting and fracturing by means of an orthogonal design method, updating the geometric model based on the construction parameters for each group of construction parameters, inputting the construction parameters into the fluid-solid coupling model, carrying out numerical solution on the fluid-solid coupling model by means of an extended finite element method based on the updated geometric model to obtain extended path parameters and geometric parameters of a crack generated under the action of prefabricated slotting and hydraulic fracturing, calculating fracture pressure relief effect evaluation index values corresponding to each group of construction parameters based on the extended path parameters and the geometric parameters, and determining target construction parameters based on the fracture pressure relief effect evaluation index values corresponding to each group of construction parameters. The scheme improves the pressure relief effect of water jet slotting fracturing roof cutting.

Inventors

ZHANG CHENYANG
ZENG QINGDONG
LEI SHUN
MA HONGYUAN
YAN YAODONG

Assignees

中煤科工开采研究院有限公司

Dates

Publication Date: 20260512
Application Date: 20260128

Claims (10)

1. The construction parameter optimization method for roof water jet slotting fracturing is characterized by comprising the following steps of: The method comprises the steps of obtaining a geometric model of drilling, slotting and fracturing and a fluid-solid coupling model, wherein the geometric model is constructed based on geomechanical parameters of a target coal mine roof, and the fluid-solid coupling model is used for simulating the expansion process of hydraulic fracturing prefabricated slots under the action of hydraulic fracturing; generating a plurality of groups of construction parameters for roof water jet slotting and fracturing by using an orthogonal design method; Updating the geometric model based on the construction parameters aiming at each group of construction parameters, inputting the construction parameters into the fluid-solid coupling model, and carrying out numerical solution on the fluid-solid coupling model by adopting an extended finite element method based on the updated geometric model to obtain extended path parameters and geometric parameters of a crack network formed by extension under the simulated prefabrication slit hydraulic fracturing effect; based on the expansion path parameters and the geometric parameters, calculating fracturing pressure relief effect evaluation index values corresponding to each group of construction parameters; and determining target construction parameters from the plurality of groups of construction parameters based on the fracturing pressure relief effect evaluation index values corresponding to each group of construction parameters.
2. The construction parameter optimization method for roof water jet slotted fracturing of claim 1, wherein the construction parameters include any one or more of: the number, length, width, depth, inclination and azimuth angle of the prefabricated cracks, and the time of hydraulic fracturing, the viscosity of fracturing fluid, the displacement and the pressure drilling interval after the prefabricated cracks, and the drilling length.
3. The construction parameter optimization method for roof water jet slotted fracturing according to claim 1, wherein the performing numerical solution on the fluid-solid coupling model by adopting an extended finite element method based on the updated geometric model comprises: determining the positions of the drill holes in the updated geometric model, and the neighborhood region and the non-neighborhood region of the drill holes; Grid division is carried out on the neighborhood region according to a first size, and grid division is carried out on the non-neighborhood region according to a second size, so that a geometric model after grid division is obtained, wherein the first size is smaller than the second size; And carrying out numerical solution on the fluid-solid coupling model by adopting an extended finite element method based on the geometrical model after grid division.
4. The method for optimizing construction parameters for roof water jet slot fracturing according to claim 3, wherein said meshing said neighborhood region according to a first size and said meshing said non-neighborhood region according to a second size comprises: Grid division is carried out on the neighborhood region according to the first size in a structured grid division mode; And carrying out grid division on the non-neighborhood region according to the second size by adopting a sweeping grid division mode.
5. The construction parameter optimization method for roof water jet slotted fracturing according to claim 1, wherein the calculating the fracturing pressure relief effect evaluation index value corresponding to each group of construction parameters based on the expansion path parameters and the geometric parameters comprises: for each group of construction parameters, respectively determining azimuth deviation index, density index and area index of the crack network based on crack propagation path parameters and geometric parameters corresponding to the construction parameters; determining a fracturing pressure relief effect evaluation index value based on the azimuth deviation index, the density index and the area index.
6. The construction parameter optimization method for roof water jet slotted fracturing of claim 5, wherein the determining a fracturing pressure relief effect evaluation index value based on the azimuth deviation index, the density index, and the area index comprises: Calculating a fracturing pressure relief effect evaluation index value by adopting the following formula: wherein A is an azimuth deviation index, B is the density index, C is an area index, W 1 is the weight of A, W 2 is the weight of B, W 3 is the weight of C, the sum of W 1 、W 2 、W 3 is 1, E is a fracturing pressure relief effect evaluation index value, and E takes a value in a range of 0-1.
7. The construction parameter optimization method for roof water jet slotted fracturing of claim 1, wherein the propagation path parameters include hydraulic fracture network azimuth, and the geometric parameters include fracture network area density, fracture network length, fracture network height and fracture network area; the method for respectively determining the azimuth deviation index, the density index and the area index of the hydraulic fracture network based on the expansion path parameters and the geometric parameters corresponding to the construction parameters comprises the following steps: the deviation index of the hydraulic fracture network orientation was calculated using the following formula: Wherein A is the azimuth deviation index of the hydraulic fracture network, For the hydraulic fracture network azimuth, Azimuth angle for coal seam inclination; The density index of the hydraulic fracture network was calculated using the following formula: wherein B is the density index of the hydraulic fracture network, In order to achieve the density of the stitch net, As a reference value for the maximum density, As a reference value for the minimum density, For the total length of the slit, Is the volume of the fracturing area; the area index of the hydraulic fracture network was calculated using the following formula: Wherein, C is the area index of the hydraulic fracture network, l is the length of the fracture network, h is the height of the fracture network, r is the area of the fracture network, For the minimum stitch area reference value, Is the maximum seam area reference value.
8. The construction parameter optimization method for roof water jet slotted fracturing according to claim 1, wherein the determining the target construction parameter based on the fracturing pressure relief effect evaluation index value corresponding to each set of construction parameters comprises: selecting a group of construction parameters with highest fracture pressure relief effect evaluation index values as target construction parameters, or Sequencing according to the fracturing pressure relief effect evaluation index values from large to small, and selecting the construction parameters corresponding to the first n fracturing pressure relief effect evaluation index values as candidate construction parameters so that a user can select and obtain target construction parameters from n groups of candidate construction parameters.
9. A construction parameter optimizing device for roof water jet slot fracturing is characterized in that includes: The system comprises an acquisition unit, a hydraulic fracturing unit and a hydraulic fracturing unit, wherein the acquisition unit is used for acquiring a geometric model and a fluid-solid coupling model of drilling slot fracturing, the geometric model is constructed based on geomechanical parameters of a target coal mine roof, and the fluid-solid coupling model is used for simulating the expansion process of hydraulic fracturing prefabricated slots under the action of hydraulic fracturing; The generation unit is used for generating a plurality of groups of construction parameters for roof water jet slotting and fracturing by using an orthogonal design method; the solving unit is used for updating the geometric model based on the construction parameters aiming at each group of construction parameters, inputting the construction parameters into the fluid-solid coupling model, and carrying out numerical solution on the fluid-solid coupling model by adopting an extended finite element method based on the updated geometric model to obtain the extended path parameters and the geometric parameters of the crack generated by the hydraulic fracturing prefabricated slotting; The evaluation unit is used for calculating fracture pressure relief effect evaluation index values corresponding to each group of construction parameters based on the expansion path parameters and the geometric parameters; And the determining unit is used for determining the target construction parameters based on the fracturing pressure relief effect evaluation index value corresponding to each group of construction parameters.
10. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the method according to any one of claims 1 to 8 when the computer program is executed.

Description

Construction parameter optimization method and device for roof water jet slotting fracturing Technical Field The disclosure relates to the technical field of coal mine safety exploitation, in particular to a construction parameter optimization method and device for roof water jet slotting and fracturing. Background Rock burst is one of main disasters affecting safe and efficient production of coal mines, and multiple rock burst accidents in recent years cause casualties, so that huge economic loss and bad social influence are brought. Hydraulic fracturing after prefabricating cracks by water jet is one of important technical means for preventing and controlling rock burst disasters. The water jet slotting fracturing technology is that firstly, drilling holes with a certain depth (generally 30-80 m) are constructed on a roof, then water jet prefabricating cracks are adopted at a plurality of positions in the drilling holes, namely, prefabricating a plurality of sections of cracks at a plurality of intervals in one drilling hole, then high-pressure water is injected to fracture a roof stratum, a hydraulic fracture net is formed in an oriented mode through the guiding action of the prefabricating cracks, the hydraulic fracture net penetrates through the roof stratum to form a roof fracture surface, therefore, the roof cutting direction and the cutting position are changed manually, the dynamic load released by roof collapse is reduced, and the impact ground pressure source prevention and control are realized. The space form of the hydraulic fracture network is determined by two aspects, namely, the physical and mechanical property condition of the overlying roof stratum and the ground stress environment, which are objective conditions and cannot be changed, and the space form of the hydraulic fracture network is determined by the combined action of the two construction parameters of hydraulic fracturing after the water jet prefabricating the fracture, so that the pressure relief effect of the water jet fracture roof is finally affected. At present, the hydraulic fracturing roof-cutting construction parameters after water jet prefabricating cracks are usually determined based on engineering experience or by referring to the construction conditions of surrounding mines, so that the hydraulic fracturing roof-cutting construction parameters have extremely high blindness and subjectivity, lack of enough scientific basis, and the roof-cutting pressure relief effect is difficult to guarantee. Disclosure of Invention In order to overcome the problems in the related art, the present disclosure provides a construction parameter optimization method and apparatus for roof water jet slot fracturing. According to a first aspect of embodiments of the present disclosure, there is provided a construction parameter optimization method for roof water jet slot fracturing, including: The method comprises the steps of obtaining a geometric model of drilling, slotting and fracturing and a fluid-solid coupling model, wherein the geometric model is constructed based on geomechanical parameters of a target coal mine roof, and the fluid-solid coupling model is used for simulating the expansion process of hydraulic fracturing prefabricated slots under the action of hydraulic fracturing; generating a plurality of groups of construction parameters for roof water jet slotting and fracturing by using an orthogonal design method; Updating the geometric model based on the construction parameters aiming at each group of construction parameters, inputting the construction parameters into the fluid-solid coupling model, and carrying out numerical solution on the fluid-solid coupling model by adopting an extended finite element method based on the updated geometric model to obtain the extended path parameters and the geometric parameters of the crack generated by the hydraulic fracturing prefabricated slotting; based on the expansion path parameters and the geometric parameters, calculating fracturing pressure relief effect evaluation index values corresponding to each group of construction parameters; and determining target construction parameters based on the fracturing pressure relief effect evaluation index values corresponding to each group of construction parameters. According to a second aspect of embodiments of the present disclosure, there is provided a construction parameter optimization apparatus for roof water jet slot fracturing, comprising: The system comprises an acquisition unit, a hydraulic fracturing unit and a hydraulic fracturing unit, wherein the acquisition unit is used for acquiring a geometric model and a fluid-solid coupling model of drilling slot fracturing, the geometric model is constructed based on geomechanical parameters of a target coal mine roof, and the fluid-solid coupling model is used for simulating the expansion process of hydraulic fracturing prefabricated slots under the action of hydraulic fracturing; The g