Method for determining collapse pressure in deep coalbed methane horizontal well, apparatus, device, and storage medium

Abstract

The present application provides a method for determining collapse pressure in a deep coalbed methane horizontal well, an apparatus, a device, and a storage medium. The method comprises: for each well section of a target horizontal well, on the basis of rock mechanical parameters of the well section and a preset horizontal principal stress formula, determining a horizontal principal stress corresponding to the well section; on the basis of the horizontal principal stress corresponding to the well section, and pre-acquired cohesion, internal friction angle, formation pore pressure, and effective stress coefficient, incrementing drilling-fluid hydrostatic pressure from zero, and iteratively processing a collapse-strength function until the value of the collapse-strength function is equal to zero; and determining the drilling-fluid hydrostatic pressure corresponding to the collapse-strength function that is equal to zero as the collapse pressure corresponding to the well section. In the present application, on the basis of a microstructural in-situ stress model and in consideration of impact factors such as the drilling-fluid hydrostatic pressure and a pore-pressure change in a wellbore filtration zone, the determination of collapse pressure is accurate and reliable, providing technical support for wellbore stability, drilling-fluid density optimization design, reduction of downhole complex accidents, and increase of drilling speed and drilling efficiency in the deep coalbed methane horizontal well.

Description

Method, device and equipment for determining collapse pressure of deep coal rock gas horizontal well and storage medium

[0001] The present application claims priority to the Chinese patent application No. 202411262130.2, filed on September 10, 2024, and entitled "Method, device and equipment for determining collapse pressure of horizontal well and storage medium", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of unconventional reservoir collapse pressure prediction, in particular to a method, device and equipment for determining collapse pressure of deep coal rock gas horizontal well and storage medium. BACKGROUND

[0003] Coal rock gas is a new type of natural gas resource between conventional gas and coal rock gas, which has the characteristics of coexistence of conventional reservoir and unconventional reservoir, symbiosis of free gas and adsorbed gas, complementary accumulation and orderly distribution of self-source gas and other-source gas. Deep coal rock gas generally refers to coal rock gas with a burial depth of more than 1500 meters, and its accumulation mechanism and geological conditions are more complex than those of shallow coal rock gas. With the increase of burial depth, the formation temperature, formation pressure and stress will increase significantly, and the difficulty and cost of exploration and development will also increase.

[0004] During the drilling process of deep coal rock gas, downhole complications frequently occur. During the scale test of deep coal rock gas horizontal well, complex accidents such as reaming difficulty and sticking caused by the collapse of the horizontal section well wall cause frequent engineering sidetracking. Collapse and pressure buildup have become an important factor affecting drilling efficiency, and an accurate and reliable collapse pressure calculation method is urgently needed in the industry. The main collapse pressure calculation models are based on the Mohr-Coulomb strength criterion and rely on geostress data to calculate the collapse pressure.

[0005] However, the selection of the geostress calculation model and method in the above method has a great influence on the determination of the final collapse pressure, which may cause the lack of necessary parameters, resulting in the inability to determine or low precision. SUMMARY

[0006] The present application provides a method, device and equipment for determining collapse pressure of deep coal rock gas horizontal well and storage medium to solve the problem of low calculation precision of collapse pressure in the prior art.

[0007] In a first aspect, the present application provides a method for determining collapse pressure of deep coal rock gas horizontal well, comprising:

[0008] For each well section of the target horizontal well, the horizontal principal stress corresponding to the well section is determined based on the rock mechanics parameters of the well section and a preset horizontal principal stress formula, and the horizontal principal stress formula is determined based on the vertical stress component, the macroscopic structure component and the local microscopic structure component.

[0009] Based on the horizontal principal stress corresponding to the well section, the pre-acquired cohesion, internal friction angle, formation pore pressure, effective stress coefficient, the liquid column pressure is accumulated from 0, and the capacity function is iteratively processed until the value of the capacity function is equal to 0, the capacity function representing the ability of the rock inside the formation to resist the shear force of the well wall;

[0010] The liquid column pressure corresponding to the capacity function being 0 is determined as the collapse pressure corresponding to the well section.

[0011] In combination with the first aspect, in some embodiments, the determination of the horizontal principal stress corresponding to the well section based on the rock mechanics parameters of the well section and the preset horizontal principal stress formula comprises:

[0012] For each well section, the formation pore pressure, the effective stress coefficient and the coal rock Poisson's ratio corresponding to the well section are acquired;

[0013] Based on the vertical stress corresponding to the well section, the formation pore pressure, the effective stress coefficient, the coal rock Poisson's ratio and the vertical stress component, the vertical stress component value corresponding to the well section is determined;

[0014] Based on the preset first tectonic stress coefficient and second tectonic stress coefficient, the vertical stress, the formation pore pressure, the effective stress coefficient and the macroscopic tectonic component, the macroscopic tectonic component value corresponding to the well section is determined;

[0015] Based on the preset third tectonic stress coefficient, the Young's modulus corresponding to the well section, the curvature coefficient corresponding to the well section, the coal rock Poisson's ratio and the local microscopic tectonic component, the local microscopic tectonic component value corresponding to the well section is determined;

[0016] The vertical stress component value, the macroscopic tectonic component value and the local microscopic tectonic component value are superimposed to obtain the horizontal principal stress corresponding to the well section.

[0017] In combination with the first aspect, in some embodiments, the iterative processing of the capacity function based on the horizontal principal stress corresponding to the well section, the pre-acquired cohesion, internal friction angle, formation pore pressure, effective stress coefficient, the liquid column pressure accumulated from 0, comprises:

[0018] Step 1, for each well section, according to a preset initial liquid column pressure, a preset seepage effect coefficient, a preset coordinate transformation coefficient, the formation pore pressure, a preset porosity corresponding to the well section, a preset permeability coefficient, the vertical stress, the maximum horizontal principal stress and the minimum horizontal principal stress in the horizontal principal stress, the three-way stress corresponding to the well section is calculated, the three-way stress includes radial stress, circumferential stress and vertical stress;

[0019] Step 2, the radial stress is determined as the minimum principal stress, and the circumferential stress is coordinate-transformed and the transformed circumferential stress is determined as the maximum principal stress;

[0020] Step 3, based on the minimum principal stress, the maximum principal stress, the internal friction angle, the formation pore pressure and the effective stress coefficient, the shear stress and the normal stress corresponding to the well section are calculated;

[0021] Step 4, according to the shear stress, the normal stress, the internal friction angle, the formation pore pressure, the effective stress coefficient and the cohesion, the value of the capacity function is calculated;

[0022] Step 5, the initial liquid column pressure is accumulated and updated to obtain a new liquid column pressure, and steps 1 to 5 are repeated until the value of the capacity function is 0.

[0023] In combination with the first aspect, in some embodiments, the method further comprises:

[0024] For each well section, based on the effective stress coefficient, the coal rock Poisson's ratio and the porosity, the seepage effect coefficient is determined.

[0025] In combination with the first aspect, in some embodiments, the method further comprises:

[0026] For each well section, according to a preset inclination angle and a well circumference angle, the coordinate transformation coefficient is determined.

[0027] In combination with the first aspect, in some embodiments, before the macroscopic tectonic component value corresponding to the well section is determined based on the preset first tectonic stress coefficient and the second tectonic stress coefficient, the vertical stress, the formation pore pressure, the effective stress coefficient and the macroscopic tectonic component, the method further comprises:

[0028] The pre-acquired elastic mechanics parameters and the data of the research area where the target horizontal well is located are brought into the vertical stress component, the macroscopic tectonic component and the local microscopic tectonic component to obtain a simultaneous equation, the elastic mechanics parameters are obtained based on rock mechanics experiments;

[0029] solving the simultaneous equations to obtain the first tectonic stress coefficient, the second tectonic stress coefficient and the third tectonic stress coefficient.

[0030] In combination with the first aspect, in some embodiments, the method further comprises:

[0031] For each well section, a tectonic feature parameter corresponding to the well section is extracted according to a pre-acquired tectonic map, and coordinate conversion is performed to obtain a converted tectonic feature parameter, the tectonic feature parameter including longitude data, latitude data and elevation data;

[0032] According to the converted tectonic feature parameter, surface fitting is performed to obtain a curvature coefficient corresponding to the well section.

[0033] In a second aspect, the application provides a device for determining a collapse pressure of a deep coal rock gas horizontal well, comprising:

[0034] A calculation module is configured to determine, for each well section of a target horizontal well, a horizontal principal stress corresponding to the well section based on rock mechanics parameters of the well section and a preset horizontal principal stress formula, the horizontal principal stress formula being determined based on a vertical stress component, a macroscopic tectonic component and a local microscopic tectonic component;

[0035] An iteration module is configured to, based on the horizontal principal stress corresponding to the well section, a pre-acquired cohesion, an internal friction angle, a formation pore pressure and an effective stress coefficient, accumulate a liquid column pressure from 0, and iteratively process a capacity function until the capacity function is equal to 0, the capacity function representing a capacity of rock inside a formation to resist a shear force of a well wall;

[0036] A determination module is configured to determine, as a collapse pressure corresponding to the well section, the liquid column pressure corresponding to the capacity function being 0.

[0037] In combination with the second aspect, in some embodiments, the calculation module comprises:

[0038] An acquisition unit is configured to, for each well section, acquire a formation pore pressure, an effective stress coefficient and a coal rock Poisson's ratio corresponding to the well section;

[0039] A first calculation unit is configured to determine, based on a vertical stress corresponding to the well section, the formation pore pressure, the effective stress coefficient, the coal rock Poisson's ratio and the vertical stress component, a vertical stress component value corresponding to the well section;

[0040] A second calculation unit is configured to determine, based on a preset first tectonic stress coefficient and a second tectonic stress coefficient, the vertical stress, the formation pore pressure, the effective stress coefficient and the macroscopic tectonic component, a macroscopic tectonic component value corresponding to the well section;

[0041] A third calculation unit is configured to determine a local micro-structure component value of the well section based on a preset third structure stress coefficient, a Young's modulus corresponding to the well section, a curvature coefficient corresponding to the well section, the coal rock Poisson's ratio, and the local micro-structure component.

[0042] A superposition unit is configured to superimpose the vertical stress component value, the macro-structure component value, and the local micro-structure component value to obtain a horizontal principal stress corresponding to the well section.

[0043] In combination with the second aspect, in some embodiments, the iteration module comprises:

[0044] A first calculation unit is configured to calculate, for each well section, a three-way stress corresponding to the well section based on a preset initial liquid column pressure, a preset seepage effect coefficient, a preset coordinate transformation coefficient, the formation pore pressure, a preset porosity corresponding to the well section, a preset permeability coefficient, the vertical stress, a maximum horizontal principal stress and a minimum horizontal principal stress in the horizontal principal stress.

[0045] A determination unit is configured to determine the radial stress as a minimum principal stress, and to perform coordinate transformation on the circumferential stress and determine the transformed circumferential stress as a maximum principal stress.

[0046] A second calculation unit is configured to calculate, based on the minimum principal stress, the maximum principal stress, the internal friction angle, the formation pore pressure, and the effective stress coefficient, a shear stress and a normal stress corresponding to the well section.

[0047] A third calculation unit is configured to calculate, based on the shear stress, the normal stress, the internal friction angle, the formation pore pressure, the effective stress coefficient, and the cohesion, a value of the capability function.

[0048] An iteration unit is configured to update the initial liquid column pressure cumulatively to obtain a new liquid column pressure, and repeat the foregoing operations until the value of the capability function is 0.

[0049] In combination with the second aspect, in some embodiments, the iteration module further comprises:

[0050] A fourth calculation unit is configured to determine, for each well section, the seepage effect coefficient based on the effective stress coefficient, the coal rock Poisson's ratio, and the porosity.

[0051] In combination with the second aspect, in some embodiments, the iteration module further comprises:

[0052] A fifth calculation unit is configured to determine, for each well section, the coordinate transformation coefficient based on a preset inclination angle and a well circumference angle.

[0053] In some embodiments, the computing module further comprises:

[0054] a unit for bringing the pre-acquired elastic mechanics parameters, data of the target horizontal well in the research area into the vertical stress component, the macroscopic structure component and the local microscopic structure component to obtain a simultaneous equation, the elastic mechanics parameters being obtained based on rock mechanics experiments;

[0055] a solving unit for solving the simultaneous equation to obtain the first structure stress coefficient, the second structure stress coefficient and the third structure stress coefficient.

[0056] In some embodiments, the computing module further comprises:

[0057] a unit for extracting, for each well section, the corresponding structure feature parameters of the well section according to the pre-acquired structure map and performing coordinate conversion to obtain converted structure feature parameters, the structure feature parameters including longitude data, latitude data and elevation data;

[0058] a fitting unit for performing surface fitting according to the converted structure feature parameters to obtain the curvature coefficient corresponding to the well section.

[0059] In a third aspect, the present application provides an electronic device, comprising: a processor, and a memory and a display connected to the processor in communication;

[0060] The memory stores computer execution instructions.

[0061] The processor executes the computer execution instructions stored in the memory to implement the horizontal well collapse pressure determination method according to any one of the first aspect.

[0062] In a fourth aspect, the present application provides a computer readable storage medium, the computer readable storage medium storing computer execution instructions, the computer execution instructions being executed by a processor to implement the deep coal rock gas horizontal well collapse pressure determination method according to any one of the first aspect.

[0063] In a fifth aspect, the present application provides a computer program product, the computer program product comprising a computer program, the computer program being executed by a processor to implement the deep coal rock gas horizontal well collapse pressure determination method according to any one of the first aspect.

[0064] The deep coal rock gas horizontal well collapse pressure determination method, device, equipment and storage medium provided by the application, for each well section of the target horizontal well, based on the rock mechanics parameters of the well section and the preset horizontal principal stress formula, determine the horizontal principal stress corresponding to the well section, based on the horizontal principal stress corresponding to the well section, the pre-acquired cohesion, internal friction angle, formation pore pressure, effective stress coefficient, start accumulating the liquid column pressure from 0, iterate the capacity function until the value of the capacity function is equal to 0, and then determine the liquid column pressure corresponding to the capacity function of 0 as the collapse pressure corresponding to the well section. Through the above method, the microstructure-based geomechanical model is used as the basis, and the influences of the liquid column pressure, wellbore filtration zone pore pressure change and other factors are considered, the determination of the collapse pressure is accurate and reliable, which can provide technical support for the stability of the deep coal horizontal well wall, the optimization design of the drilling fluid density, the reduction of downhole complex accidents and the realization of drilling speed and efficiency improvement. BRIEF DESCRIPTION OF DRAWINGS

[0065] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate an embodiment consistent with the present application and, together with the description, serve to explain the principles of the application.

[0066] FIG. 1 is a flowchart of the deep coal rock gas horizontal well collapse pressure determination method according to an embodiment of the present application;

[0067] FIG. 2 is a flowchart of the deep coal rock gas horizontal well collapse pressure determination method according to an embodiment of the present application;

[0068] FIG. 3 is a flowchart of the deep coal rock gas horizontal well collapse pressure determination method according to an embodiment of the present application;

[0069] FIG. 4 is a schematic diagram of horizontal section division of horizontal well X01;

[0070] FIG. 5 is a schematic diagram of surface fitting;

[0071] FIG. 6 is a structural diagram of the deep coal rock gas horizontal well collapse pressure determination device according to an embodiment of the present application;

[0072] FIG. 7 is a structural diagram of the deep coal rock gas horizontal well collapse pressure determination device according to an embodiment of the present application;

[0073] FIG. 8 is a structural diagram of the deep coal rock gas horizontal well collapse pressure determination device according to an embodiment of the present application;

[0074] FIG. 9 is a structural diagram of an electronic device according to an embodiment of the present application.

[0075] The present application has been shown and described with reference to the preferred embodiments. Equivalent mechanisms and methods incorporating the spirit of the present application are intended to be within the scope of the dependent claims. DETAILED DESCRIPTION

[0076] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The description herein is intended for illustrating the conceptual aspects of the present application by way of example and is not intended to limit the scope of the present application in any way. Further, the description of the exemplary embodiments is intended for describing the apparatus and methods in accordance with some aspects of the present application, as detailed in the appended claims.

[0077] Coal rock gas, also known as "gas", is natural gas stored in coal seams, which is unconventional natural gas stored in coal seams in adsorbed state. Deep coal rock gas usually refers to coal rock gas with a burial depth of more than 1500 meters, and its accumulation mechanism and geological conditions are more complex than those of shallow coal rock gas. With the increase of burial depth, the formation temperature, formation pressure and stress will increase significantly, and the exploration and development difficulty and cost will also increase. During the drilling of deep coal rock gas, downhole complexities frequently occur. During the scale test of deep coal rock gas horizontal wells, the difficulties in reaming and sticking caused by the collapse of the well wall in the horizontal section cause the frequent occurrence of engineering sidetracking, and collapse and pressure build-up have become important factors affecting the drilling efficiency. Therefore, there is an urgent need for an accurate and reliable collapse pressure calculation method. At present, the main collapse pressure calculation models are based on the Mohr-Coulomb strength criterion and rely on the calculation of collapse pressure by using the in-situ stress data. However, the selection of the in-situ stress calculation model and method in the above method has a great influence on the determination of the final collapse pressure, which may cause the lack of necessary parameters, resulting in the inability to determine or low precision.

[0078] To solve the above problems, the application provides a deep coal rock gas horizontal well collapse pressure determination method, device, equipment and storage medium, which realizes high-precision determination of the horizontal well collapse pressure. Specifically, the current main collapse pressure calculation model is based on the Mohr-Coulomb strength criterion, and relies on the ground stress data to calculate the collapse pressure. The selection of the ground stress calculation model and method has a great influence on the calculation result of the final collapse pressure. If the shale mineral component content, mud filtrate invasion amount and shale hydration rock mechanics parameters are considered, the shale collapse pressure can be calculated more reliably. However, there are great differences between coal rock and shale in lithology, physical property, mechanical strength and pore structure, so the method does not have popularization and application value in the field of deep coal rock gas collapse pressure calculation. If the coal seam is regarded as being composed of discrete blocks, the stress analysis of the coal block most likely to collapse between two face cleats is carried out, and then a collapse pressure calculation model is established. The method has certain reference value for shallow coal rock gas with poor coal structure and fragmented structure, but deep coal rock gas is mainly of primary structure and has good medium structure, so the method is not applicable in the field of deep coal rock gas. Considering these problems, the inventor studies whether a reliable ground stress calculation model can be used as the basis to establish a wellbore stress distribution model in polar coordinates considering the influence of factors such as initial stress, liquid column pressure and wellbore filtration zone pore pressure change, and fully considers the influence of ground stress, well trajectory and drilling fluid soaking time on the stability of the coal rock wellbore. Based on this, the technical scheme of the application is proposed.

[0079] The technical scheme of the application and how the technical scheme solves the above technical problems will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described again in some embodiments. The embodiments of the application will be described below with reference to the drawings.

[0080] FIG. 1 is a flowchart of a deep coal rock gas horizontal well collapse pressure determination method according to an embodiment of the application. As shown in FIG. 1, the method comprises the following steps.

[0081] S101: For each well section of the target horizontal well, based on the rock mechanics parameters of the well section and the preset horizontal principal stress formula, the horizontal principal stress corresponding to the well section is determined.

[0082] In this step, the horizontal principal stress is one of the key factors affecting the stability of the well wall, which is directly related to whether the well wall rock can withstand various mechanical actions in the drilling process without collapse, so the accuracy of the horizontal principal stress is important when determining the collapse pressure. Therefore, for each section of the target horizontal well, rock mechanics experiments are performed on the section to obtain rock mechanics parameters. Based on the rock mechanics parameters, the horizontal principal stress of the section is determined by the horizontal principal stress formula. The horizontal principal stress formula can be expressed as: horizontal principal stress = vertical stress component + macroscopic structure component + local microscopic structure component.

[0083] Specifically, for each section, the formation pore pressure, effective stress coefficient and coal rock Poisson's ratio corresponding to the section are obtained. Based on the vertical stress, formation pore pressure, effective stress coefficient, coal rock Poisson's ratio and vertical stress component corresponding to the section, the vertical stress component value corresponding to the section is determined. The pre-obtained elastic mechanics parameters and data of the research area where the target horizontal well is located are brought into the vertical stress component, macroscopic structure component and local microscopic structure component to obtain a system of equations. The system of equations is solved to obtain the first, second and third structure stress coefficients. Based on the pre-set first and second structure stress coefficients, vertical stress, formation pore pressure, effective stress coefficient and macroscopic structure component, the macroscopic structure component value corresponding to the section is determined. For each section, the structure feature parameters corresponding to the section are extracted from the pre-obtained structure map and are subjected to coordinate transformation to obtain transformed structure feature parameters. Curve fitting is performed according to the transformed structure feature parameters to obtain the curvature coefficient corresponding to the section. Based on the pre-set third structure stress coefficient, Young's modulus corresponding to the section, curvature coefficient corresponding to the section, coal rock Poisson's ratio and local microscopic structure component, the local microscopic structure component value corresponding to the section is determined. The vertical stress component value, macroscopic structure component value and local microscopic structure component value are superimposed to obtain the horizontal principal stress corresponding to the section

[0084] S102: Based on the horizontal principal stress corresponding to the section, the pre-obtained cohesion, internal friction angle, formation pore pressure, effective stress coefficient, the liquid column pressure is accumulated from 0, and the capacity function is iteratively processed until the value of the capacity function is equal to 0.

[0085] S103: The liquid column pressure corresponding to the capacity function of 0 is determined as the collapse pressure corresponding to the section.

[0086] After determining the horizontal principal stress corresponding to each section, in order to accurately and efficiently determine the collapse pressure, the capacity function can be iteratively processed until the value of the capacity function is 0. The capacity function represents the ability of the rock inside the formation to resist the shear force of the well wall.

[0087] The ability of the rock inside the formation to resist the shear force of the wellbore wall plays a crucial role in determining the collapse pressure. The ability directly affects the stability of the wellbore wall and is one of the key factors in assessing whether the wellbore wall will collapse during drilling. The ability of the rock inside the formation to resist shear failure is an inherent property of the rock material itself, including two main parameters, cohesion and internal friction angle. The shear strength of the rock (including cohesion and internal friction angle) is a key parameter in determining the size of the collapse pressure. When the shear strength of the rock inside the formation is high, the wellbore wall rock can withstand greater shear force without failure, thereby improving the stability of the wellbore wall. Conversely, if the shear strength of the rock is low, the wellbore wall may collapse under the action of a smaller shear force.

[0088] If the ability of the rock inside the formation to resist the shear force of the wellbore wall is 0, any small shear force will cause the wellbore wall to collapse. In this case, the only way to maintain the stability of the wellbore wall is to balance the formation pressure by the drilling fluid column pressure to prevent the wellbore wall from being subjected to excessive shear force. Therefore, the fluid column pressure at this time is the collapse pressure. The fluid column pressure can be set to 0 to start accumulation, and then the ability function is iteratively calculated based on the horizontal principal stress, cohesion, internal friction angle, formation pore pressure, and effective stress coefficient corresponding to the well section. When the value of the ability function is 0, the fluid column pressure is the collapse pressure corresponding to the well section.

[0089] Specifically, for each well section, the seepage effect coefficient is calculated based on the effective stress coefficient, coal rock Poisson's ratio, and porosity. The coordinate transformation coefficient is calculated according to the preset inclination angle and the angle around the well. The three-dimensional stress corresponding to the well section is calculated according to the pre-set initial fluid column pressure, the pre-set seepage effect coefficient, the pre-set coordinate transformation coefficient, the formation pore pressure, the pre-set porosity corresponding to the well section, the pre-set permeability coefficient, the vertical stress, the maximum and minimum horizontal principal stresses in the horizontal principal stress, and then the radial stress is determined as the minimum principal stress, the circumferential stress is coordinate-transformed and the transformed circumferential stress is determined as the maximum principal stress. The shear stress and normal stress corresponding to the well section are calculated based on the minimum principal stress, the maximum principal stress, the internal friction angle, the formation pore pressure, and the effective stress coefficient. The value of the ability function is calculated according to the shear stress, the normal stress, the internal friction angle, the formation pore pressure, the effective stress coefficient, and the cohesion. The initial fluid column pressure is updated by accumulation to obtain a new fluid column pressure, and the above operations are repeated until the value of the ability function is 0.

[0090] The deep coal rock gas horizontal well collapse pressure determination method provided in the embodiment is based on the rock mechanics parameters of each well section of the target horizontal well and a preset horizontal principal stress formula, determines the horizontal principal stress corresponding to the well section, based on the horizontal principal stress corresponding to the well section, the pre-acquired cohesion, internal friction angle, formation pore pressure, and effective stress coefficient, accumulates the liquid column pressure from 0, iteratively processes the capacity function until the value of the capacity function is equal to 0, and then determines the liquid column pressure corresponding to the capacity function of 0 as the collapse pressure corresponding to the well section. Through the above method, the collapse pressure is determined based on the microstructure-based geomechanical model, and the influences of the liquid column pressure, the wellbore filtration zone pore pressure change and other factors are considered, so that the determination of the collapse pressure is accurate and reliable, which can provide technical support for the wellbore stability of the deep coal horizontal well, the optimization design of the drilling fluid density, the reduction of downhole complex accidents, and the realization of drilling speed and efficiency improvement.

[0091] FIG. 2 is a flowchart of the deep coal rock gas horizontal well collapse pressure determination method provided in the embodiment of the application. As shown in FIG. 2, based on the above embodiment, step S101 specifically includes:

[0092] S201: For each well section, acquire the formation pore pressure, effective stress coefficient and coal rock Poisson's ratio corresponding to the well section.

[0093] In this step, in order to accurately calculate the horizontal principal stress corresponding to each well section, the formation pore pressure, effective stress coefficient and coal rock Poisson's ratio corresponding to each well section are important parameters for determining the horizontal principal stress, so the formation pore pressure, effective stress coefficient and coal rock Poisson's ratio corresponding to each well section can be pre-acquired.

[0094] Specifically, the formation pore pressure and effective stress coefficient corresponding to each well section are acquired by querying the geological data of the target horizontal well. The coal rock Poisson's ratio is obtained through the rock triaxial compression experiment, wherein the transverse strain value and the longitudinal strain value are determined according to the experimental data obtained through the rock triaxial compression experiment, and then the coal rock Poisson's ratio is calculated according to the following formula:

[0095] It should be noted that the confining pressure in the above rock triaxial compression experiment is set as the in-situ effective stress of the coal seam.

[0096] S202: Based on the vertical stress, formation pore pressure, effective stress coefficient, coal rock Poisson's ratio and vertical stress component corresponding to the well section, determine the vertical stress component value corresponding to the well section.

[0097] In this step, after obtaining the formation pore pressure, effective stress coefficient and coal rock Poisson's ratio of each well section, the vertical stress component value corresponding to each well section is calculated based on the vertical stress, formation pore pressure, effective stress coefficient, coal rock Poisson's ratio and vertical stress component corresponding to each well section.

[0098] Specifically, the vertical stress component is represented as:

[0099] Wherein, σ H V , σ h V are the components caused by the vertical stress in the maximum horizontal principal stress direction and the minimum horizontal principal stress direction, MPa, v represents the coal rock Poisson's ratio, σ V represents the vertical stress, P p represents the formation pore pressure, and a represents the effective stress coefficient.

[0100] S203: Determine the macroscopic tectonic component value corresponding to the well section based on the preset first tectonic stress coefficient and second tectonic stress coefficient, vertical stress, formation pore pressure, effective stress coefficient and macroscopic tectonic component.

[0101] In this step, based on the macroscopic tectonic component, the first tectonic stress coefficient and the second tectonic stress coefficient, the vertical stress, the formation pore pressure and the effective stress coefficient are used to determine the macroscopic tectonic component value corresponding to each well section.

[0102] Specifically, the macroscopic tectonic component is represented as:

[0103] σ h mac = β1(σ V - αP p )

[0104] σ H mac = β2(σ V - αP p )

[0105] In the formula, σ H mac , σ h mac are the components caused by the macroscopic tectonic in the maximum horizontal principal stress direction and the minimum horizontal principal stress direction, MPa, σ V represents the vertical stress, P p represents the formation pore pressure, a represents the effective stress coefficient, and β1 and β2 represent the first tectonic stress coefficient and the second tectonic stress coefficient, which are calculated based on geological data in advance.

[0106] S204: Determine the local micro-structural component value corresponding to each well section based on the preset third tectonic stress coefficient, the Young's modulus corresponding to the well section, the curvature coefficient corresponding to the well section, the coal rock Poisson's ratio and the local micro-structural component.

[0107] In this step, based on the local micro-structural component, the third tectonic stress coefficient and the Young's modulus corresponding to each well section, the curvature coefficient corresponding to the well section, the coal rock Poisson's ratio are determined to determine the local micro-structural component value corresponding to each well section.

[0108] Specifically, the local micro-structural component is represented as:

[0109] Wherein, σ x represents the stress component of the local micro-structural component corresponding to the x-axis direction in the rectangular coordinate system, σ y represents the stress component of the local micro-structural component corresponding to the y-axis direction in the rectangular coordinate system, τ xy represents the shear stress of the x-y plane, E represents the Young's modulus, v represents the coal rock Poisson's ratio, a, b, c represent the curvature coefficient, β3 represents the third tectonic stress coefficient, and the curvature coefficient and the third tectonic stress coefficient are calculated based on the geological data in advance.

[0110] S205: Superimpose the vertical stress component value, the macro-structural component value and the local micro-structural component value to obtain the horizontal principal stress corresponding to the well section.

[0111] In this step, after calculating the vertical stress component value, the macro-structural component value and the local micro-structural component value of each well section through the foregoing steps, the vertical stress component value, the macro-structural component value and the local micro-structural component value are superimposed according to the calculation method of the horizontal principal stress corresponding to each well section in the foregoing embodiment, so as to obtain the horizontal principal stress corresponding to each well section.

[0112] Optionally, on the basis of the above steps, before step S203, further comprising:

[0113] S206: Bring the pre-acquired elastic mechanics parameters and the data of the research area where the target horizontal well is located into the vertical stress component, the macro-structural component and the local micro-structural component to obtain the simultaneous equations.

[0114] S207: Solve the simultaneous equations to obtain the first tectonic stress coefficient, the second tectonic stress coefficient and the third tectonic stress coefficient.

[0115] Before calculating the horizontal principal stress of each well section, the tectonic stress coefficient needs to be calculated in advance.

[0116] Specifically, according to the data of the target horizontal well in the research area, the data of the horizontal principal stress, the elastic mechanics parameters obtained by the rock mechanics experiment, the effective stress coefficient, the formation pore pressure and the formation pore pressure coefficient are obtained, the obtained data are brought into the vertical stress component, the macroscopic structure component and the local microscopic structure component, and then the simultaneous equations are obtained by simultaneous equation, and the first structure stress coefficient, the second structure stress coefficient and the third structure stress coefficient are obtained by solving the simultaneous equations.

[0117] For example, by analyzing the vertical stress component, the macroscopic structure component and the local microscopic structure component, the vertical stress component is equal in each direction, and no special consideration is needed, the macroscopic structure component and the local microscopic structure component are different in direction, and then the same coordinate system is needed for calculation, and then the macroscopic structure component can be converted into the same coordinate system as the local microscopic structure component according to the coordinate conversion.

[0118] The specific conversion method can be converted by the following formula:

[0119] Wherein, L can be represented as:

[0120] And the macroscopic structure component can be converted to:

[0121] Wherein, σ x represents the stress component of the macroscopic structure component corresponding to the x-axis direction in the rectangular coordinate system, σ y represents the stress component of the macroscopic structure component corresponding to the y-axis direction in the rectangular coordinate system, τ xy represents the shear stress of the x-y plane corresponding to the macroscopic structure component,

[0122] And the horizontal maximum principal stress can be represented as:

[0123] Wherein, σ max is the horizontal maximum principal stress, MPa; is the angle between σ max and x-axis, rad.

[0124] For example, taking the geological data of well 8-9 and well 8-9 to 1 in the target horizontal well area as an example, the structure stress coefficient is solved, and the simultaneous equations are obtained as follows:

[0125] By solving the above simultaneous equations, the following is obtained:

[0126] The structural stress coefficient calculated above can be applied to any position in the target horizontal well region, and combined with the rock mechanics parameters of the position to obtain the magnitude and direction of the horizontal principal stress.

[0127] In one possible implementation manner, the step S101 can further include:

[0128] S208: For each well section, according to the pre-acquired structure map, the structure characteristic parameters corresponding to the well section are extracted, and coordinate conversion is performed to obtain the converted structure characteristic parameters.

[0129] S209: According to the converted structure characteristic parameters, surface fitting is performed to obtain the curvature coefficient corresponding to the well section.

[0130] It should be noted that in the calculation process of the local microstructure component, the different well sections correspond to different curvature coefficients, and therefore before the calculation of the local microstructure component of each well section, the curvature coefficient of each well section needs to be determined.

[0131] Specifically, for each well section, the structure characteristic parameters near the well location in the study area are extracted by using the structure map, the latitude-longitude-elevation data are extracted, and coordinate conversion is needed to convert the geodetic coordinates into X-Y-Z coordinates in the rectangular coordinate system. The binary quadratic fitting equation ω(x,y) of the block surface can be obtained by using the surface fitting tool, and the parameters a, b and c are extracted: ω(x,y) = ax 2 +by 2 +cxy+dx+ey+f.

[0132] In the formula, a, b, c, d, e and f all represent the curvature coefficient, which is dimensionless.

[0133] The deep coal rock gas horizontal well collapse pressure determination method provided in the embodiment is used for each well section, the formation pore pressure, the effective stress coefficient and the coal rock Poisson's ratio corresponding to the well section are obtained, the vertical stress component value corresponding to the well section is determined based on the vertical stress, the formation pore pressure, the effective stress coefficient, the coal rock Poisson's ratio and the vertical stress component of the well section, the pre-obtained elastic mechanics parameters and the data of the research area where the target horizontal well is located are brought into the vertical stress component, the macroscopic structure component and the local microscopic structure component to obtain the simultaneous equations, the first structure stress coefficient, the second structure stress coefficient and the third structure stress coefficient are obtained by solving the simultaneous equations, the macroscopic structure component value corresponding to the well section is determined based on the preset first structure stress coefficient and the second structure stress coefficient, the vertical stress, the formation pore pressure, the effective stress coefficient and the macroscopic structure component, for each well section, the structure characteristic parameters corresponding to the well section are extracted according to the pre-obtained structure map, and coordinate conversion is performed to obtain the converted structure characteristic parameters, the curvature coefficient corresponding to the well section is obtained by surface fitting according to the converted structure characteristic parameters. The local microscopic structure component value corresponding to the well section is determined based on the preset third structure stress coefficient, the Young's modulus corresponding to the well section, the curvature coefficient corresponding to the well section, the coal rock Poisson's ratio and the local microscopic structure component, and the vertical stress component value, the macroscopic structure component value and the local microscopic structure component value are superimposed to obtain the horizontal principal stress corresponding to the well section. Through the above method, the comprehensiveness, accuracy, scientificity, adaptability and intelligence are improved, and the prediction ability is enhanced, and the safety and efficiency of coal rock gas exploration and development are also improved.

[0134] FIG. 3 is a flowchart of the deep coal rock gas horizontal well collapse pressure determination method provided in the embodiment of the application, as shown in FIG. 3, on the basis of the foregoing embodiments, step S102 specifically includes:

[0135] Step 1, for each well section, the three-directional stresses corresponding to the well section are calculated according to the pre-set initial liquid column pressure, the preset seepage effect coefficient, the pre-set coordinate conversion coefficient, the formation pore pressure, the pre-set porosity corresponding to the well section, the pre-set permeability coefficient, the vertical stress, the maximum horizontal principal stress and the minimum horizontal principal stress in the horizontal principal stress.

[0136] In this step, the collapse pressure of each well section is also closely related to the stress state around the well wall, then the three-directional stresses of the well section are determined, wherein the three-directional stresses include the radial stress, the circumferential stress and the vertical stress.

[0137] Specifically, the three-directional stresses can be calculated by the following formula:

[0138] wherein, σ r is the radial stress, MPa; σ θσ is the circumferential stress, MPa; v For vertical stress, MPa; σ θz σ rθ τ rz σ is the stress component in cylindrical coordinates, MPa; σ is the coordinate transformation coefficient, dimensionless; H σ h These are the maximum and minimum horizontal principal stresses, respectively, in MPa; σ z Let be the vertical stress component in the cylindrical coordinate system, MPa; A, B, C, D, E, F, G, H, J are coordinate transformation coefficients; δ is the permeability coefficient, taken as 0.3; φ is the porosity; p i p is the liquid column pressure, in MPa. p The pressure is the bottom pore pressure, in MPa.

[0139] Step 2: Determine the radial stress as the minimum principal stress, perform coordinate transformation on the circumferential stress, and determine the transformed circumferential stress as the maximum principal stress.

[0140] In this step, the triaxial stress at the wellbore wall is obtained through the steps described above. The triaxial stress not only reflects the stress on the wellbore wall in different directions but also directly relates to its stability and resistance to collapse. The maximum principal stress typically determines the maximum stress on the wellbore wall in a particular direction. During drilling, if the maximum principal stress exceeds the compressive or tensile strength of the wellbore rock (depending on the nature of the stress), the wellbore wall may fail or collapse. The minimum principal stress reflects the minimum stress on the wellbore wall in a particular direction. Although the minimum principal stress itself does not directly determine the stability of the wellbore wall (because failure usually occurs in the direction of the maximum principal stress), the difference between it and the maximum principal stress (i.e., the stress difference) is an important parameter for assessing wellbore stability. A larger stress difference may mean that the wellbore wall is more susceptible to shear failure. Therefore, the maximum and minimum principal stresses are determined from the calculated triaxial stresses.

[0141] Specifically, since the triaxial stress obtained from the above steps is represented in cylindrical coordinates, it needs to be converted to a rectangular coordinate system when determining the principal stresses and minimum principal stresses.

[0142] Where X, Y, and Z represent coefficients, which are calculated using the following formula:

[0143] Where A, B, C, D, E, F, G, H, and J are coordinate transformation coefficients, and σ H σ h The maximum and minimum horizontal principal stresses are respectively, MPa and σ. v For vertical stress, MPa.

[0144] The transformed formula yields σ.j is the maximum principal stress, i.e. the circumferential stress, σ i is the minimum principal stress, i.e. the radial stress.

[0145] Step 3, based on the minimum principal stress, the maximum principal stress, the internal friction angle, the formation pore pressure and the effective stress coefficient, the shear stress and the normal stress corresponding to the well section are calculated.

[0146] In this step, after the minimum principal stress and the maximum principal stress are obtained, the shear stress and the normal stress of each well section are calculated based on the following formula:

[0147] wherein τ is the shear stress, MPa, σ n is the normal stress, MPa, σ1 is the maximum principal stress, σ3 is the minimum principal stress, P p represents the formation pore pressure, is the internal friction angle, and α represents the effective stress coefficient.

[0148] Step 4, according to the shear stress, the normal stress, the internal friction angle, the formation pore pressure, the effective stress coefficient and the cohesion, the value of the capacity function is calculated.

[0149] In this step, after the shear stress and the normal stress are calculated above, the capacity function is obtained based on the Mohr-Coulomb strength criterion, and the value of the capacity function is calculated based on the capacity function, the shear stress, the normal stress, the internal friction angle, the formation pore pressure, the effective stress coefficient and the cohesion.

[0150] Specifically, the capacity function is represented as:

[0151] wherein σ1 is the maximum principal stress, σ3 is the minimum principal stress, P p represents the formation pore pressure, is the internal friction angle, and α represents the effective stress coefficient, C0 is the cohesion, and M is a coefficient, p i is the liquid column pressure.

[0152] M can be calculated by the following formula:

[0153] wherein C0 is the cohesion, is the internal friction angle, τ is the shear stress, and σ n is the normal stress.

[0154] It should be noted that when the capacity function is calculated for the first time, the liquid column pressure is 0.

[0155] Step 5, the initial liquid column pressure is updated cumulatively to obtain a new liquid column pressure, and steps 1 to 5 are repeated until the value of the capacity function is 0.

[0156] By cumulatively updating the initial liquid column pressure, the new liquid column pressure is brought into the capacity function until the value of the capacity function is 0, and the calculation is ended.

[0157] Optionally, the well circumference angle is changed to increase the liquid column pressure from small to large, and the collapse pressure values under different well circumference angles can be obtained. The minimum value is the minimum well internal pressure that can maintain the surrounding rock of the horizontal well without shear failure, that is, the collapse pressure.

[0158] Optionally, on the basis of the above steps, step S102 can further include:

[0159] Step 6, for each well section, the seepage effect coefficient is calculated based on the effective stress coefficient, the coal rock Poisson's ratio and the porosity.

[0160] The seepage coefficient is a parameter describing the water permeability of fissured rock, which has an important influence on the stability of the well wall. In drilling operations, seepage may cause a pressure difference around the well wall, which will exert additional stress on the well wall. When the stress caused by seepage is superimposed on other stresses in drilling operations (such as formation pressure, drilling fluid pressure, etc.), the stress on the well wall may exceed its bearing capacity, thereby causing collapse. Seepage may also affect the stability of the well wall by changing the formation pressure distribution around the well wall. For example, seepage may cause the pore water pressure in the formation to decrease, thereby causing the effective stress of the formation to increase, which is not conducive to the stability of the well wall. Therefore, for each well section, the seepage effect coefficient of each well section is calculated, which can be calculated by the following formula:

[0161] Wherein, K1 is the seepage effect coefficient; α is the effective stress coefficient; v is the Poisson's ratio, and φ is the porosity.

[0162] Step 7, for each well section, the coordinate transformation coefficient is calculated according to the preset inclination angle and the well circumference angle.

[0163] In this step, the coordinate transformation coefficient of step 2 can be determined according to the inclination angle and the well circumference angle, which can be calculated by the following formula:

[0164] Wherein, the inclination angle of the horizontal well ψ is 90°, the inclination direction of the maximum horizontal principal stress Ω is changed by the well circumference angle θ.

[0165] It should be noted that in the process of updating the liquid column pressure, the well circumference angle is also changing, and the coordinate transformation coefficient is also changing constantly in the superposition process.

[0166] The deep coal rock gas horizontal well collapse pressure determination method provided by the embodiment is based on the effective stress coefficient, the coal rock Poisson's ratio and the porosity, calculates the seepage effect coefficient, and calculates the coordinate transformation coefficient according to the preset inclination angle and the well circumference angle. According to the preset initial liquid column pressure, the preset seepage effect coefficient, the preset coordinate transformation coefficient, the formation pore pressure, the preset porosity corresponding to the well section, the preset permeability coefficient, the vertical stress, the maximum horizontal principal stress and the minimum horizontal principal stress in the horizontal principal stress, the three-dimensional stress corresponding to the well section is calculated, and then the radial stress is determined as the minimum principal stress, the circumferential stress is converted in the coordinate and the converted circumferential stress is determined as the maximum principal stress, the shear stress and the normal stress corresponding to the well section are calculated based on the minimum principal stress, the maximum principal stress, the internal friction angle, the formation pore pressure and the effective stress coefficient, and then the value of the capacity function is calculated according to the shear stress, the normal stress, the internal friction angle, the formation pore pressure, the effective stress coefficient and the cohesion, the initial liquid column pressure is accumulated and updated to obtain a new liquid column pressure, and the above operation is repeated until the value of the capacity function is 0. By introducing the seepage effect coefficient and the coordinate transformation coefficient, the method more accurately reflects the spatial variation of the underground fluid flow and the stress state, thereby improving the accuracy of the collapse pressure prediction. Not only the basic parameters such as the formation pore pressure, the effective stress coefficient and the coal rock Poisson's ratio are considered, but also the complex factors such as the inclination angle, the well circumference angle, the seepage effect and the horizontal principal stress distribution are considered, so that the prediction result is more comprehensive and reliable. At the same time, the iterative method is used to continuously adjust the initial liquid column pressure to simulate the stress state and the failure process of the well wall under different pressure conditions, thereby improving the flexibility.

[0167] The following takes the horizontal section of the horizontal well X01 well as an example to describe the horizontal well collapse pressure determination method provided by the embodiment of the application. Specifically,

[0168] Table 1 is the coordinates and elevations of the extracted points in the first well section

[0169] Fig. 4 is a schematic diagram of the division of the horizontal section of the horizontal well X01 well, as shown in Fig. 4, the horizontal section of the horizontal well X01 well is divided into six sections. The longitude and latitude coordinates and the elevations of a plurality of points (20 to 30) in each section are extracted by using the construction diagram, the longitude and latitude-elevation data are extracted, and coordinate conversion is needed to convert the geodetic coordinates into X-Y-Z coordinates in the rectangular coordinate system, so as to facilitate the subsequent surface fitting. Table 1 is the coordinates and elevations of the extracted points in the first well section.

[0170] Fig. 5 is a schematic diagram of surface fitting, a quadratic surface is fitted by using the extracted data, as shown in Fig. 5, the coefficients of two quadratic terms and a cross term are determined, wherein a = -0.02273, b = 0.05687 and c = -0.0339.

[0171] Through well logging and laboratory experiments, the static rock mechanics data of the target layer are determined, including the elastic modulus of 6 GPa, the Poisson's ratio of 0.35, and the effective stress coefficient of 0.756; the formation pressure gradient of the target layer is determined by using injection pressure drop test data, which is 8.886 MPa / km; the component caused by the vertical stress of the target layer, the component caused by the macrostructure, and the component caused by the microstructure are calculated by using the vertical stress of the target layer, the formation pressure, the Poisson's ratio, and the effective stress coefficient. Based on the direction of the horizontal stress caused by the microstructure as the basic axis, the horizontal stress components in other directions are decomposed into the direction, an equation containing two macrostructure stress coefficients and one microstructure stress coefficient is established, the least square fitting solution is determined, and the structure coefficient is obtained.

[0172] By using the structure coefficient, the horizontal maximum principal stress σ H , the horizontal minimum principal stress σ h , and the overburden stress σ v of each section are calculated in combination with the Poisson's ratio, the elastic modulus, etc. of each section, and the corresponding vertical depth and the inclined depth interval MD of each section are read in the geological model, as shown in Table 2.

[0173] The well inclination direction of the relative maximum horizontal principal stress is taken as 90° (drilling most safely perpendicular to the direction of the maximum horizontal principal stress), the well inclination angle is taken as 90° (horizontal well), the hole wall angle θ is taken as 90°, the porosity φ is taken as 0.02, the formation pore pressure gradient P p is taken as 0.8886 MPa / km, the effective stress coefficient α is taken as 0.756, the coal rock Poisson's ratio v is taken as 0.35 measured by triaxial compression experiment, the internal friction is taken as 17 MPa, and the internal friction angle is taken as 25°. The intermediate parameters are calculated, in which the parameters A, B, C, D, E, F, G, H, J, K_1 of each section are dimensionless and are 7.50E-33, -1, 3, 1, -0.7, 0.7, -1.22E-16, 7.50E-33, 1.22E-16, 0.014892308 respectively. The different parameters of each section are listed in Table 3.

[0174] Table 2 stress and depth parameters of each section of the horizontal well

[0175] Table 3 intermediate parameters

[0176] In combination with the above parameters, the iterative method is used according to the calculation process, the liquid column pressure P i is accumulated starting from 0 until f(P i ) is 0, and the collapse pressure of each section is calculated, as shown in Table 4.

[0177] Table 4 collapse pressure of the horizontal well

[0178] Figure 6 is a structural schematic diagram of an embodiment of the device for determining the collapse pressure of a deep coal rock gas horizontal well provided by the present application, as shown in Figure 6, the device for determining the collapse pressure of a horizontal well 600 comprises:

[0179] The calculation module 601 is configured to, for each well section of the target horizontal well, calculate the horizontal principal stress corresponding to the well section based on the rock mechanics parameters of the well section and a preset horizontal principal stress formula, the horizontal principal stress formula being determined based on the vertical stress component, the macroscopic tectonic component and the local microscopic tectonic component.

[0180] The iteration module 602 is configured to, based on the horizontal principal stress corresponding to the well section, the pre-acquired cohesion, internal friction angle, formation pore pressure and effective stress coefficient, accumulate the liquid column pressure from 0, and iteratively calculate the capacity function until the capacity function is equal to 0, the capacity function representing the capacity of the rock inside the formation to resist the shear force of the well wall.

[0181] The determination module 603 is configured to determine the liquid column pressure corresponding to the capacity function being 0 as the collapse pressure corresponding to the well section.

[0182] Figure 7 is a structural schematic diagram of an embodiment of the device for determining the collapse pressure of a deep coal rock gas horizontal well provided by the present application, as shown in Figure 7, the calculation module 601 specifically comprises:

[0183] The acquisition unit 701 is configured to, for each well section, acquire the formation pore pressure, effective stress coefficient and coal rock Poisson's ratio corresponding to the well section;

[0184] The first calculation unit 702 is configured to calculate the vertical stress component value corresponding to the well section based on the vertical stress, formation pore pressure, effective stress coefficient, coal rock Poisson's ratio and vertical stress component corresponding to the well section;

[0185] The second calculation unit 703 is configured to calculate the macroscopic tectonic component value corresponding to the well section based on the preset first tectonic stress coefficient and second tectonic stress coefficient, vertical stress, formation pore pressure, effective stress coefficient and macroscopic tectonic component;

[0186] The third calculation unit 704 is configured to calculate the local microscopic tectonic component value corresponding to the well section based on the preset third tectonic stress coefficient, Young's modulus corresponding to the well section, curvature coefficient corresponding to the well section, coal rock Poisson's ratio and local microscopic tectonic component;

[0187] The superposition unit 705 is configured to superimpose the vertical stress component value, macroscopic tectonic component value and local microscopic tectonic component value to obtain the horizontal principal stress corresponding to the well section.

[0188] Optionally, the calculation module 701 further comprises:

[0189] The simultaneous unit 706 is configured to bring the pre-acquired elastic mechanics parameters and data of the research area where the target horizontal well is located into the vertical stress component, the macroscopic structure component and the local microscopic structure component to obtain the simultaneous equations, and the elastic mechanics parameters are obtained based on rock mechanics experiments.

[0190] The solving unit 707 is configured to solve the simultaneous equations to obtain the first structure stress coefficient, the second structure stress coefficient and the third structure stress coefficient.

[0191] The extraction and conversion unit 708 is configured to extract the structure feature parameters corresponding to each well section according to the pre-acquired structure map, and perform coordinate conversion to obtain the converted structure feature parameters, and the structure feature parameters include longitude data, latitude data and elevation data.

[0192] The fitting unit 709 is configured to perform surface fitting according to the converted structure feature parameters to obtain the curvature coefficient corresponding to the well section.

[0193] FIG. 8 is a structural schematic diagram of a deep coal rock gas horizontal well collapse pressure determination device according to an embodiment of the present application, as shown in FIG. 8, the iteration module 602 specifically includes:

[0194] The first calculation unit 801 is configured to calculate the three-way stress corresponding to each well section according to the pre-set initial liquid column pressure, the pre-set seepage effect coefficient, the pre-set coordinate conversion coefficient, the formation pore pressure, the pre-set porosity corresponding to the well section, the pre-set permeability coefficient, the vertical stress, the maximum horizontal principal stress and the minimum horizontal principal stress in the horizontal principal stress.

[0195] The determination unit 802 is configured to determine the radial stress as the minimum principal stress, and perform coordinate conversion on the circumferential stress and determine the converted circumferential stress as the maximum principal stress.

[0196] The second calculation unit 803 is configured to calculate the shear stress and the normal stress corresponding to the well section based on the minimum principal stress, the maximum principal stress, the internal friction angle, the formation pore pressure and the effective stress coefficient.

[0197] The third calculation unit 804 is configured to calculate the value of the capacity function according to the shear stress, the normal stress, the internal friction angle, the formation pore pressure, the effective stress coefficient and the cohesion.

[0198] The iteration unit 805 is configured to update the initial liquid column pressure to obtain a new liquid column pressure, and repeat the foregoing operations until the value of the capacity function is 0.

[0199] Optionally, the iteration module 702 further includes:

[0200] The fourth calculation unit 806 is configured to calculate, for each well section, a seepage effect coefficient based on the effective stress coefficient, the coal rock Poisson's ratio and the porosity.

[0201] The fifth calculation unit 807 is configured to calculate, for each well section, a coordinate transformation coefficient according to the preset inclination angle and the azimuth angle.

[0202] The deep coal rock gas horizontal well collapse pressure determination device provided by the above-mentioned embodiments can be used to execute the deep coal rock gas horizontal well collapse pressure determination method provided by any of the above-mentioned embodiments, and has similar implementation principles and technical effects, which will not be described herein again.

[0203] FIG. 9 is a structural schematic diagram of an electronic device provided by an embodiment of the present application. As shown in FIG. 9, the electronic device 900 includes a processor 902 and a memory 901 connected with the processor 902 in communication.

[0204] The memory 901 stores computer execution instructions.

[0205] The processor 902 executes the computer execution instructions stored in the memory 901 to implement the deep coal rock gas horizontal well collapse pressure determination method in any method embodiment.

[0206] The embodiment of the present application also provides a computer readable storage medium, and the computer readable storage medium stores computer execution instructions. When the processor executes the computer execution instructions, the computer execution instructions are used to implement the deep coal rock gas horizontal well collapse pressure determination method in any method embodiment.

[0207] The above-mentioned computer readable storage medium can be realized by any type of volatile or non-volatile storage devices or a combination thereof, such as static random access memory, electrically erasable programmable read-only memory, erasable programmable read-only memory, programmable read-only memory, read-only memory, magnetic storage, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0208] Optionally, the readable storage medium is coupled to the processor, so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in the device.

[0209] The embodiment of the present application further provides a computer program product, which comprises a computer program stored in a computer readable storage medium, at least one processor can read the computer program from the computer readable storage medium, and the at least one processor executes the computer program to implement the technical solutions provided by any of the method embodiments.

[0210] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0211] It is to be understood that the application is not limited to the precise details of design and construction described herein and illustrated in the drawings. The scope of the application is indicated by the appended claims rather than by the foregoing description.

Claims

1. A method for determining collapse pressure for a deep coal shale gas horizontal well, the method comprising: The method comprises the following steps: For each well section of the target horizontal well, the rock mechanics parameters of the well section and a preset horizontal principal stress formula are used to determine the corresponding horizontal principal stress of the well section, and the horizontal principal stress formula is determined based on a vertical stress component, a macroscopic structure component and a local microscopic structure component; Based on the corresponding horizontal principal stress of the well section, the pre-obtained cohesion, internal friction angle, formation pore pressure, effective stress coefficient, the liquid column pressure is accumulated from 0, and the capacity function is iteratively processed until the value of the capacity function is equal to 0, wherein the capacity function represents the ability of the rock inside the formation to resist the shear force of the well wall; The liquid column pressure corresponding to the capacity function of 0 is determined as the collapse pressure of the well section.

2. The method of claim 1, wherein, The method comprises the following steps: For each well section, the formation pore pressure, effective stress coefficient and coal rock Poisson's ratio corresponding to the well section are obtained; Based on the vertical stress, formation pore pressure, effective stress coefficient, coal rock Poisson's ratio and vertical stress component corresponding to the well section, the vertical stress component value corresponding to the well section is determined; Based on the preset first and second structure stress coefficients, vertical stress, formation pore pressure, effective stress coefficient and macroscopic structure component, the macroscopic structure component value corresponding to the well section is determined; Based on the preset third structure stress coefficient, Young's modulus, curvature coefficient, coal rock Poisson's ratio and local microscopic structure component corresponding to the well section, the local microscopic structure component value corresponding to the well section is determined; The vertical stress component value, macroscopic structure component value and local microscopic structure component value are superimposed to obtain the horizontal principal stress corresponding to the well section.

3. The method of claim 2, wherein, The method comprises the following steps: Step 1, for each well section, the initial liquid column pressure, preset seepage effect coefficient, pre-set coordinate transformation coefficient, formation pore pressure, preset porosity corresponding to the well section, pre-set permeability coefficient, vertical stress, maximum horizontal principal stress and minimum horizontal principal stress in the horizontal principal stress are used to calculate the three-dimensional stress corresponding to the well section, wherein the three-dimensional stress includes radial stress, circumferential stress and vertical stress; Step 2, the radial stress is determined as the minimum principal stress, and the circumferential stress is coordinate-transformed and the transformed circumferential stress is determined as the maximum principal stress; Step 3, based on the minimum principal stress, maximum principal stress, internal friction angle, formation pore pressure and effective stress coefficient, the shear stress and normal stress corresponding to the well section are calculated; Step 4, based on the shear stress, normal stress, internal friction angle, formation pore pressure, effective stress coefficient and cohesion, the value of the capacity function is calculated. Step 5, update the initial liquid column pressure accumulation to obtain a new liquid column pressure, and repeat steps 1 to 5 until the value of the capacity function is 0.

4. The method of claim 3, wherein, The method further comprises: For each well section, based on the effective stress coefficient, the coal rock Poisson's ratio and the porosity, the seepage effect coefficient is determined.

5. The method of claim 3, wherein, The method further comprises: For each well section, according to the preset inclination angle and the azimuth angle, the coordinate transformation coefficient is determined.

6. The method of claim 2, wherein, Before determining the macroscopic tectonic component value corresponding to the well section based on the preset first tectonic stress coefficient and the second tectonic stress coefficient, the vertical stress, the formation pore pressure, the effective stress coefficient and the macroscopic tectonic component, the method further comprises: The pre-acquired elastic mechanics parameters and the data of the research area where the target horizontal well is located are brought into the vertical stress component, the macroscopic tectonic component and the local microscopic tectonic component to obtain a system of equations, and the elastic mechanics parameters are obtained based on rock mechanics experiments; The system of equations is solved to obtain the first tectonic stress coefficient, the second tectonic stress coefficient and the third tectonic stress coefficient.

7. The method of claim 2, wherein, The method further comprises: For each well section, according to the pre-acquired tectonic map, the tectonic feature parameters corresponding to the well section are extracted, and coordinate conversion is performed to obtain converted tectonic feature parameters, and the tectonic feature parameters include longitude data, latitude data and elevation data; According to the converted tectonic feature parameters, surface fitting is performed to obtain the curvature coefficient corresponding to the well section.

8. A device for determining collapse pressure for a deep coal shale gas horizontal well, characterized by, It comprises: A calculation module is configured to determine, for each well section of a target horizontal well, a horizontal principal stress size and direction corresponding to the well section based on rock mechanics parameters of the well section and a preset horizontal principal stress formula, and the horizontal principal stress formula is determined based on a vertical stress component, a macroscopic tectonic component and a local microscopic tectonic component. An iteration module is configured to accumulate a liquid column pressure from 0 based on the horizontal principal stress size and direction corresponding to the well section, pre-acquired cohesion, internal friction angle, formation pore pressure, effective stress coefficient, and iteratively process a capacity function until the capacity function is equal to 0, and the capacity function represents the ability of the rock inside the formation to resist the shear force of the well wall. A determination module is configured to determine, as a collapse pressure corresponding to the well section, the liquid column pressure corresponding to the capacity function being 0.

9. An electronic device, comprising: It comprises: A processor and a memory and a display connected to the processor in communication; The memory stores computer execution instructions; The processor executes the computer execution instructions stored in the memory to implement the deep coal rock gas horizontal well collapse pressure determination method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer execution instructions, and the computer execution instructions are executed by the processor to implement the deep coal rock gas horizontal well collapse pressure determination method according to any one of claims 1 to 7.

11. A computer program product, characterised in that, The computer program product comprises a computer program, and the computer program is executed by the processor to implement the deep coal rock gas horizontal well collapse pressure determination method according to any one of claims 1 to 7.

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