CN-122021400-A - Method, device and storage medium for constructing damage constitutive model of coal rock

CN122021400ACN 122021400 ACN122021400 ACN 122021400ACN-122021400-A

Abstract

The application discloses a method and a device for constructing a damage constitutive model for coal rock and a storage medium, and belongs to the technical field of coal rock damage. The method comprises the steps of obtaining a plurality of coal rock air pressure damage factors of coal rock under a plurality of coal rock air pressures, a plurality of coal rock hydration damage factors under a plurality of drilling fluid soaking time periods and a coal rock load damage factor under a load stress effect, determining a plurality of coal rock total damage factors according to each coal rock air pressure damage factor, each coal rock hydration damage factor and the coal rock load damage factor, determining a coal rock maximum nominal stress-coal rock damage-coal rock maximum effective stress relation according to the plurality of coal rock total damage factors and the obtained coal rock maximum residual stress, and constructing a nominal stress-damage-strain relation according to the nominal stress-damage-effective stress relation and the preset strain-effective stress relation to represent a coal rock damage constitutive model which can improve the prediction accuracy of the coal rock damage degree.

Inventors

ZHANG HUI
Lv Kunhong
LI JUN
An Jintao
WANG XINRUI
YANG HONGWEI
LIAN WEI
ZHANG GENG

Assignees

中国石油大学(北京)

Dates

Publication Date: 20260512
Application Date: 20251226

Claims (10)

1. The construction method of the damage constitutive model for the coal rock is characterized by comprising the following steps of: respectively acquiring a plurality of coal rock air pressure damage factors corresponding to the coal rock under a plurality of coal rock air pressures, a plurality of coal rock hydration damage factors corresponding to the coal rock under a plurality of drilling fluid soaking time periods and a coal rock load damage factor under the action of load stress; Determining a plurality of coal rock total damage factors of the coal rock according to the coal rock air pressure damage factors, the coal rock hydration damage factors and the coal rock load damage factors; Determining a coal rock maximum nominal stress-coal rock damage-coal rock maximum effective stress relation corresponding to the coal rock according to a plurality of coal rock total damage factors and the pre-acquired coal rock maximum residual stress of the coal rock; And constructing a coal rock maximum nominal stress-coal rock damage-coal rock strain relation of the coal rock according to the coal rock maximum nominal stress-coal rock damage-coal rock maximum effective stress relation and a preset coal rock maximum strain-coal rock maximum effective stress relation so as to represent a damage constitutive model of the coal rock.
2. The method of constructing according to claim 1, wherein the determining a plurality of total damage factors of the coal rock based on each of the gas pressure damage factors of the coal rock, each of the hydration damage factors of the coal rock, and the load damage factor of the coal rock includes: Wherein, the Is the total damage factor of the coal and the rock, Is the gas pressure damage factor of the coal rock, Is the hydration damage factor of the coal rock, Is a coal rock load damage factor.
3. The method of claim 1, wherein the coal rock hydration damage factor is determined by the following equation: Wherein, the Is the hydration damage factor of the coal rock, For the average hydration volume of the coal rock, For the hydration damage coefficient, the water-soluble polymer, For an initial coal rock bulk modulus of the coal rock, In order to preset the effective stress coefficient of the steel, In order to achieve the chemical potential of the drilling fluid, For the concentration of the drilling fluid, Is the coefficient of hydration expansion associated with the chemical potential of the drilling fluid.
4. The method of claim 1, wherein the coal rock maximum nominal stress-coal rock damage-coal rock maximum effective stress relationship is determined by the following equation: Wherein, the Is the maximum nominal stress of the coal rock, For the maximum effective stress of the coal rock, Is the maximum residual stress of the coal rock, Is the total damage factor of coal and rock.
5. The method of claim 1, wherein the coal rock maximum nominal stress-coal rock damage-coal rock strain relationship comprises the following formula: Wherein, the Is the maximum nominal stress of the coal rock, For the maximum strain level of the coal rock, As an initial coal-rock elastic modulus of the coal rock, For the poisson's ratio of the coal rock, For a minimum nominal stress of the coal rock, For the maximum residual stress of the coal rock, Is the total damage factor of coal and rock.
6. The method of claim 1, wherein the constructing method further comprises: Acquiring a coal rock pressure value corresponding to the coal rock pressure born by the coal rock, a drilling fluid soaking time of the coal rock in the drilling fluid and a load stress value corresponding to a load stress effect; Determining peak value coal rock maximum nominal stress, peak value coal rock strain degree, coal rock damage elastic modulus, weibull distribution shape parameter, weibull distribution proportion parameter and coal rock maximum residual stress of the coal rock under the coupling action of coal rock gas pressure action, drilling fluid hydration action and load stress action according to the coal rock gas pressure value, the drilling fluid soaking time length and the load stress value; Based on the coal rock damage constitutive model, determining a stress-strain theoretical curve of the coal rock under the coupling action of the gas pressure action of the coal rock, the hydration action of drilling fluid and the loading stress action according to the maximum nominal stress of the peak coal rock, the strain degree of the peak coal rock, the damage elastic modulus of the coal rock, the Weibull distribution shape parameter, the Weibull distribution proportion parameter and the maximum residual stress of the coal rock; and judging whether the damage constitutive model of the coal rock is effective or not according to the stress-strain theoretical curve and a preset stress-strain experimental curve.
7. The method of claim 6, wherein determining whether the damage constitutive model of the coal rock is valid based on the stress-strain theoretical curve and a preset stress-strain experimental curve comprises: determining the curve coincidence degree between the stress-strain theoretical curve and a preset stress-strain experimental curve; Under the condition that the curve overlap ratio is larger than or equal to a preset curve overlap ratio threshold value, determining that the damage constitutive model of the coal rock is effective; And under the condition that the curve coincidence degree is smaller than a preset curve coincidence degree threshold value, determining that the damage constitutive model of the coal rock is invalid.
8. A construction device for a damage constitutive model of coal rock, characterized by comprising: A memory configured to store instructions, and A processor configured to invoke the instructions from the memory and when executing the instructions is capable of implementing a method of constructing a damage constitutive model for coal rock according to any of claims 1 to 7.
9. A construction apparatus for a damage constitutive model of coal rock, characterized by comprising: the construction device for a damage constitutive model of coal rock according to claim 8.
10. A machine-readable storage medium having instructions stored thereon for causing a machine to perform the method of constructing a damage constitutive model for coal rock according to any one of claims 1 to 7.

Description

Method, device and storage medium for constructing damage constitutive model of coal rock Technical Field The application relates to the technical field of coal rock damage, in particular to a method and a device for constructing a damage constitutive model of coal rock and a storage medium. Background With the progress of unconventional natural gas exploration technology, deep coal and rock gas resource exploration and development are advanced. In the deep coal rock gas development process, coal rock is easy to produce degradation damage, and main reasons of the coal rock include pore pressure change, fluid-solid coupling effect, temperature effect, chemical effect and the like, wherein the hydration effect of drilling fluid and the coal rock gas pressure effect are key factors for influencing the stability of the coal rock. In the prior art, drucker-Prager damage criteria are adopted to respectively quantify damage to coal and rock caused by drilling fluid hydration or coal and rock gas absorption, however, drucker-Prager damage criteria only quantify damage to coal and rock caused by drilling fluid hydration or coal and rock gas pressure under the condition of processing different rock types and more complex stress states, and accurate prediction results of coal and rock degradation damage are difficult to obtain. Therefore, the prior art has the problem of lower accuracy in predicting the degree of damage to coal rock degradation. Disclosure of Invention The embodiment of the application aims to provide a method, a device, equipment and a storage medium for constructing a damage constitutive model of coal rock, which are used for solving the problem of low accuracy in predicting the degradation damage degree of the coal rock in the prior art. In order to achieve the above object, a first aspect of the present application provides a method for constructing a damage constitutive model for coal rock, the method comprising: Respectively acquiring a plurality of coal rock air pressure damage factors corresponding to the coal rock under a plurality of coal rock air pressures, a plurality of coal rock hydration damage factors corresponding to the coal rock under a plurality of drilling fluid soaking time periods and a coal rock load damage factor under the action of load stress; determining a plurality of total damage factors of the coal rock according to the air pressure damage factors of the coal rock, the hydration damage factors of the coal rock and the load damage factors of the coal rock; Determining a coal rock maximum nominal stress-coal rock damage-coal rock maximum effective stress relation corresponding to the coal rock according to the total damage factors of the plurality of coal rocks and the pre-acquired coal rock maximum residual stress of the coal rock; And constructing a coal rock maximum nominal stress-coal rock damage-coal rock strain relation according to the coal rock maximum nominal stress-coal rock damage-coal rock maximum effective stress relation and the preset coal rock maximum strain-coal rock maximum effective stress relation so as to represent a coal rock damage constitutive model. In the embodiment of the application, the coal rock total damage factor of the coal rock is determined according to the coal rock air pressure damage factor, the coal rock hydration damage factor and the coal rock load damage factor, and the method comprises the following steps: Wherein, the Is the total damage factor of the coal and the rock,Is the gas pressure damage factor of the coal rock,Is the hydration damage factor of the coal rock,Is a coal rock load damage factor. In the embodiment of the application, the coal rock hydration damage factor is determined by the following formula: Wherein, the Is the hydration damage factor of the coal rock,Is the average hydration volume of the coal rock,For the hydration damage coefficient, the water-soluble polymer,Is the initial coal rock volume modulus of the coal rock,In order to preset the effective stress coefficient of the steel,In order to achieve the chemical potential of the drilling fluid,For the concentration of the drilling fluid,Is the coefficient of hydration expansion associated with the chemical potential of the drilling fluid. In the embodiment of the application, the relationship between the maximum nominal stress of the coal rock and the maximum effective stress of the coal rock and the coal rock damage is determined by the following formula: Wherein, the Is the maximum nominal stress of the coal rock,For the maximum effective stress of the coal rock,Is the maximum residual stress of the coal rock,Is the total damage factor of coal and rock. In the embodiment of the application, the relationship between the maximum nominal stress of the coal and the coal damage and the coal strain comprises the following formula: Wherein, the Is the maximum nominal stress of the coal rock,Coal rock being coal rock the degree of maximum strain is determin