Three-dimensional well group fracturing casing mechanical response modeling analysis method

Abstract

The invention provides a three-dimensional well group fracturing casing mechanical response modeling analysis method which comprises the following steps: performing three-dimensional geomechanical modeling of the whole area of a three-dimensional well group to obtain a three-dimensional geomechanical model; performing near-wellbore geomechanical modeling on the basis of the three-dimensional geomechanical model to obtain a near-wellbore model; and setting two studies to solve the near wellbore model. Reference is provided for casing deformation position and casing deformation quantity prediction in the three-dimensional well group fracturing process, and the casing damage risk existing in the actual fracturing operation process is prevented and reduced in advance.

Description

Technical Field

[0001] This invention relates to the field of mechanical simulation analysis technology for oil and gas well casing, and in particular to a method for modeling and analyzing the mechanical response of fracturing casing in three-dimensional well groups. Background Technology

[0002] Shale oil, as an emerging petroleum resource, has become a global exploration and development hotspot and is considered a strategic substitute for stabilizing and increasing crude oil production in my country. Conventional vertical well fracturing for shale oil production is ineffective and difficult to establish production, while single horizontal well development struggles to effectively utilize thick vertical reservoirs. Using a three-dimensional well network of well groups can develop shale oil reservoirs more effectively than single wells, maximizing reservoir reserves control and improving development efficiency.

[0003] As the sole conduit for fracturing operations in shale oil multi-well groups, the structural integrity of the casing is crucial for ensuring the safe and efficient development of shale oil. Compared to traditional single-well fracturing operations, multi-well group fracturing involves more and more complex fractures, significant inter-well interference, and a more prominent issue of casing integrity. Therefore, accurately modeling the fracturing casing in multi-well groups and employing a combined global-local approach to conduct mechanical response analysis, clarifying the distribution patterns of casing stress and deformation, is of great significance for the study of casing integrity in multi-well group fracturing.

[0004] In recent years, various research institutions and scholars have successively proposed mechanical analysis methods for fracturing casing. For example, Chinese patent application CN112257230A, published on January 22, 2021, entitled "A Mechanical Analysis and Calculation Method for Casing under Alternating Pressure in Horizontal Wells," discloses a method for analyzing and calculating the mechanical distribution and radial displacement of the casing under alternating pressure in horizontal wells. This method can be used to solve problems such as unclear mechanical analysis and uncertain calculation methods when alternating pressure exists within the casing during existing horizontal well fracturing processes. However, fracturing operations in shale oil multi-stage well groups can cause inter-well stress disturbance effects, resulting in significant changes in the load on the horizontal well casing. In such cases, this method cannot be used for casing mechanical response analysis.

[0005] Furthermore, CN115324560A, "A Method for Determining the Location of Fracturing-Induced Oil and Gas Casing Deformation Using In-Ground Stress Field Simulation," discloses a method for determining the location of fracturing-induced oil and gas casing deformation using in-ground stress field simulation. This method can predict the location of fracturing-induced oil and gas casing deformation by constructing a detailed in-ground stress field for a block and using this detailed in-ground stress field as input data for subsequent fracturing and casing deformation simulations. However, this analytical method only considers the induced in-ground stress changes during single-well fracturing and cannot simulate the induced stress field changes during fracturing of a three-dimensional well group, thus failing to accurately obtain the stress and deformation patterns of the fracturing casing in a three-dimensional well group.

[0006] Current casing mechanical response analysis and modeling methods do not consider the interference effect of inter-well fracturing stress in 3D well groups, resulting in an inability to provide a detailed description of the loads and boundary conditions of each casing within the 3D well group. This leads to inaccurate mechanical response analysis of fracturing casing in 3D well groups. Therefore, establishing a mechanical response modeling and analysis method suitable for fracturing casing in 3D well groups is an important prerequisite for further research on the integrity of casing in shale oil 3D well groups. Summary of the Invention

[0007] In view of the above problems, the present invention is proposed to provide an integrated digital twin characterization method for fracturing that overcomes or at least partially solves the above problems.

[0008] According to one aspect of the present invention, a method for modeling and analyzing the mechanical response of fracturing casing in a three-dimensional well group is provided, the method comprising:

[0009] Three-dimensional geomechanical modeling of the entire well group was carried out to obtain a three-dimensional geomechanical model;

[0010] Based on the aforementioned three-dimensional geomechanical model, near-wellbore geomechanical modeling is performed to obtain the near-wellbore model;

[0011] Two studies were set up to solve the near-wellbore model.

[0012] Optionally, the three-dimensional geomechanical modeling of the entire well group specifically includes:

[0013] A three-dimensional well group basic database within the block was constructed, and structural modeling, lithofacies modeling, and reservoir property modeling were performed to obtain a three-dimensional geomechanical model of the block.

[0014] Based on the fracturing design scheme developed by the three-dimensional well group, the fracturing construction process of the three-dimensional well group is simulated to generate an unstructured mesh and hydraulic fracture network after fracturing. This is then transformed into a new hydraulic fracture network that includes the pressure within the fracture, which is used to solve the formation stress field and displacement field after fracturing. Simulation data of formation displacement and stress distribution after fracturing are obtained and compared with the formation displacement and stress distribution before fracturing.

[0015] Optionally, the near-wellbore geomechanical modeling based on the three-dimensional geomechanical model specifically includes:

[0016] Based on the full-area three-dimensional geomechanical model of shale oil well groups, near-wellbore geomechanical models for various well locations were established, and corresponding mechanical material properties of casing, cement sheath and near-wellbore formation were added to obtain near-wellbore geomechanical models with added mechanical material properties.

[0017] The model is added with formation displacement fields before and after fracturing as boundary conditions for near-wellbore mechanical simulation analysis. The stress, strain and displacement changes of casing, cement sheath and near-wellbore formation under various well locations are solved to determine the casing locations with the maximum casing stress and formation displacement in each well location in the three-dimensional well group, which are regarded as the dangerous areas of wellbore structure.

[0018] Optionally, the setting of two studies to solve the near-wellbore model specifically includes:

[0019] Based on the structural parameters of the casing, cement sheath, and formation near the wellbore in the structurally hazardous area, a local three-dimensional finite element simulation model of the casing-cement sheath-formation was established.

[0020] Material properties are added to the three-dimensional finite element simulation model, and the contact relationships between the casing-cement sheath and the cement sheath-formation are set. The formation stress in the near-wellbore model analysis results is set as the external load of the local model, and the formation displacement is set as the external boundary condition of the local model. The internal pressure and temperature loads of the casing are set according to the fracturing construction parameters of the three-dimensional well group. The dynamic changes of casing stress and deformation during the fracturing construction of the three-dimensional well group are solved, and the strength verification and structural integrity analysis of the fracturing casing are performed.

[0021] Optionally, the basic database of the three-dimensional well group specifically includes: well location coordinates, well inclination, well trajectory, drilling stratification, logging data, and breakpoint data.

[0022] Optionally, when establishing near-wellbore geomechanical models for multiple well locations, homogenized modeling is adopted, and the casing, cement sheath, and near-wellbore formation materials are all single-layer homogeneous materials.

[0023] Optionally, the three-dimensional geomechanical modeling of the entire well group specifically includes:

[0024] Set up meshes for overlying, underlying, and lateral rock layers. The overlying rock layers generally extend to the ground surface. When extending the underlying rock layers, the depth should ensure that the entire model has a suitable aspect ratio. Extend the lateral rock layer mesh by extending to a specified distance or by a specified multiple. Add planes to the outer layer of the lateral mesh to ensure uniform application of boundary conditions. The planes should be set to rigid.

[0025] Establish the constitutive relations of the material and determine that the rock is an anisotropic Mohr-Coulomb constitutive model, with the following relations:

[0026]

[0027] In the formula, R mc It is a measure of the shape of the yield surface on the π plane; is the soil friction angle, i.e., the inclination angle of the Mohr-Coulomb yield surface on the qp surface; C is the soil cohesion, MPa;

[0028] Input crack data, determine crack strength curves, perform crack direction analysis, and realize a discrete crack network model;

[0029] By setting the number of fracturing stages and the displacement parameters, a three-dimensional well group fracturing simulation of shale oil was conducted to obtain the formation stress field and displacement field after fracturing.

[0030] Optionally, the near-wellbore geomechanical modeling based on the three-dimensional geomechanical model specifically includes:

[0031] Determine the top and bottom depths of the near-wellbore model. For casing completion, the top depth starts from the wellhead.

[0032] The near-wellbore model is established based on cylindrical coordinates. After determining the inner and outer boundaries of the model, the number of meshes in the tangential, radial, and axial directions is input to complete the mesh generation.

[0033] After establishing the near-wellbore model mesh, mechanical modeling was performed, and the geomechanical simulation parameters of the rock were set respectively. The mud density was set according to the actual drilling parameters.

[0034] Add mechanical parameters for the sleeve and cement ring.

[0035] Optionally, the geomechanical simulation parameters of the rock may specifically include Young's modulus, Poisson's ratio, rock strength, pore pressure, geostress, and mud density.

[0036] Optionally, the mechanical parameters of the sleeve and cement ring specifically include: elastic parameters, sleeve strength, cement ring strength, and density.

[0037] This invention provides a method for modeling and analyzing the mechanical response of casing in three-dimensional well group fracturing. The method includes: performing three-dimensional geomechanical modeling of the entire three-dimensional well group to obtain a three-dimensional geomechanical model; performing near-wellbore geomechanical modeling based on the three-dimensional geomechanical model to obtain a near-wellbore model; and setting up two studies to solve the near-wellbore model. This provides a reference for predicting casing deformation location and deformation during three-dimensional well group fracturing, thereby preventing and reducing the risk of casing damage during actual fracturing operations.

[0038] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 A flowchart illustrating a method for modeling and analyzing the mechanical response of a three-dimensional well group fracturing casing, provided as an embodiment of the present invention. Detailed Implementation

[0041] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0042] The terms "comprising" and "having," and any variations thereof, in the specification, embodiments, claims, and drawings of this invention are intended to cover non-exclusive inclusion, such as including a series of steps or units.

[0043] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0044] like Figure 1 As shown, a three-dimensional well group fracturing casing mechanical response modeling and analysis method based on co-simulation includes:

[0045] Step S1: Construct a basic database of three-dimensional well groups within the block, perform structural modeling, lithofacies modeling, and reservoir attribute modeling to obtain a three-dimensional geomechanical model of the block; based on the fracturing design scheme developed by the three-dimensional well group, simulate the fracturing construction process of the three-dimensional well group, generate unstructured meshes and hydraulic fracture networks after fracturing, and transform them into new hydraulic fracture networks containing intra-fracture pressure to solve the formation stress field and displacement field after fracturing, so as to obtain simulation data of formation displacement and stress distribution after fracturing, and compare and analyze them with the formation displacement and stress distribution before fracturing.

[0046] Step S2: Based on the full-area three-dimensional geomechanical model of the shale oil well group, establish near-wellbore geomechanical models for different well locations, and add corresponding mechanical material properties of casing, cement sheath, and near-wellbore formation to obtain near-wellbore geomechanical models with added mechanical material properties; add formation displacement fields before and after fracturing to the model as boundary conditions for near-wellbore mechanical simulation analysis, solve for stress, strain, and displacement changes of casing, cement sheath, and near-wellbore formation at different well locations, and use this to determine the casing locations with the maximum casing stress and the maximum formation displacement at each well location in the three-dimensional well group, as the dangerous areas of the wellbore structure.

[0047] Step S3: Based on the structural parameters of the casing, cement sheath, and formation near the wellbore in the structurally hazardous area, establish a local three-dimensional finite element simulation model of the casing-cement sheath-formation. Add material properties to the model, set the contact relationships between the casing-cement sheath and the cement sheath-formation, set the formation stress in the near-wellbore model analysis results as the external load of the local model, set the formation displacement as the external boundary condition of the local model, and set the internal pressure and temperature loads of the casing according to the fracturing operation parameters of the three-dimensional well group to solve the dynamic changes of casing stress and deformation during the fracturing operation of the three-dimensional well group, and perform strength verification and structural integrity analysis of the fracturing casing.

[0048] In step S1, the data required for the basic database of shale oil three-dimensional well groups include: well location coordinates, well inclination, well trajectory, drilling stratification, logging data, and breakpoint data.

[0049] In step S2, when establishing near-wellbore geomechanical models for different well locations, homogenization modeling is adopted, and the casing, cement sheath, and near-wellbore formation materials are all single-layer homogeneous materials.

[0050] In step S2, when establishing near-wellbore geomechanical models for different well locations, the dimensions of the near-wellbore geomechanical models are determined based on the wellbore structure data in the design requirements. The near-wellbore model includes the near-wellbore formation, cement sheath, and casing from the outside to the inside, and the outer diameter and wall thickness of the casing and cement sheath are set.

[0051] In step S2, when establishing near-wellbore geomechanical models for different well locations, the material property parameters of the rock are set, including: Young's modulus, Poisson's ratio, density, degree of consolidation, rock strength, friction angle, etc. In addition, the material property parameters of the casing also need to be set, including: Young's modulus, Poisson's ratio, yield strength, and density, etc.

[0052] In step S3, when establishing a local three-dimensional finite element simulation model of the casing-cement sheath-formation, the casing, cement sheath, and formation are all simulated using solid elements.

[0053] In step S3, the contact relationship between the casing-cement sheath and the cement sheath-formation is set to surface-to-surface contact.

[0054] In step S3, the maximum value of formation displacement and the formation stress at the corresponding location in the near-wellbore geomechanical model are extracted. The formation displacement is added as a displacement constraint on the upper and lower sides of the local casing-cement sheath-formation three-dimensional finite element simulation model. At the same time, the formation stress is added as an initial geostress field around the local casing-cement sheath-formation three-dimensional finite element simulation model. The casing stress and deformation distribution in the local casing-cement sheath-formation three-dimensional finite element simulation model are calculated.

[0055] Step S1, in performing three-dimensional geomechanical modeling of the entire well group, specifically includes the following steps:

[0056] ① Set up meshes for overlying, underlying, and lateral rock layers. Overlying rock layers generally extend to the ground surface to facilitate the calculation of overlying pressure through rock density. When extending the underlying rock layers, its depth should ensure that the entire model has a suitable aspect ratio. Extend the lateral rock layer mesh by extending it to a specified distance or by a specified multiple. Add a plane to the outer layer of the lateral mesh to ensure uniform application of boundary conditions. This plane should be set to rigid.

[0057] ②Establish the constitutive relations of the material and determine that the rock is an anisotropic Mohr-Coulomb constitutive model, with the following relations:

[0058]

[0059] In the formula, R mc It is a measure of the shape of the yield surface on the π plane; θ is the soil friction angle, i.e., the inclination angle of the Mohr-Coulomb yield surface on the qp surface; C is the soil cohesion, MPa.

[0060] ③ Input crack data, determine crack strength curve, perform crack direction analysis, and realize discrete crack network model.

[0061] ④ Set construction parameters such as the number of fracturing stages and the displacement rate, and conduct fracturing simulation of shale oil three-dimensional well groups to obtain the formation stress field and displacement field after fracturing.

[0062] Step S2 involves performing near-wellbore geomechanical modeling based on the three-dimensional geomechanical model of the entire well group. This includes elastic parameters, strength parameters, faults / fractures, and the magnitude and direction of the geostress field. These three-dimensional attribute parameters will be used to define the parameters and boundary conditions of the near-wellbore geomechanical model. The specific steps for near-wellbore geomechanical modeling are as follows:

[0063] ① First, determine the top and bottom depths of the near-wellbore model. For casing completion, the top depth starts from the wellhead.

[0064] ② The near-wellbore model is established based on the cylindrical coordinate system. After determining the inner and outer boundaries of the model, the number of tangential, radial and axial meshes is input to complete the mesh generation.

[0065] ③ After establishing the near-wellbore model mesh, mechanical modeling is performed, setting the geomechanical simulation parameters for the rock, including Young's modulus, Poisson's ratio, rock strength, pore pressure, in-situ stress, and mud density. The mud density is set according to the actual drilling parameters. The geomechanical simulation parameters of the rock are derived from the three-dimensional geomechanical attribute volume established in S1 above, and can be directly converted and read.

[0066] ④ Based on this, add the mechanical parameters of the casing and cement ring. These include elastic parameters (elastic modulus, Poisson's ratio), casing strength (yield strength, soft / hardening coefficient), cement ring strength (uniaxial compressive strength, hardening coefficient, internal friction angle, tensile strength, expansion angle), and density.

[0067] In step S2 above, after completing the near-wellbore geomechanical modeling, two studies are set up to solve the near-wellbore model. Study 1 solves for the comprehensive stress of the casing in the near-wellbore model, which includes the casing Mises stress, radial stress, and circumferential stress. The location of the maximum Mises stress is designated as the casing's critical area. Study 2 solves for the stress and displacement field distribution of the formation at this location in the near-wellbore model, including the maximum and minimum horizontal and vertical in-situ stresses at this location, as well as the formation displacement at this location. The solved formation stress and displacement fields can provide load conditions and constraint relationships for the next step of local casing-cement sheath-formation composite structure modeling and mechanical analysis, and can provide a basis for further analysis of the dynamic changes in casing stress and deformation during fracturing operations.

[0068] Step S3, the specific steps for modeling the local casing-cement sheath-formation assembly are as follows:

[0069] ① Determine the unit types for casing, cement sheath, and formation structure, simulate each structure using solid elements, and establish casing, cement sheath, and formation according to design requirements.

[0070] ②Based on the elastic modulus, Poisson's ratio, cohesion, and internal friction angle in the design requirements, establish the structural material properties of the casing, cement sheath, and formation, and assign corresponding structures.

[0071] ③ Combine the casing, cement sheath, and formation into a single composite structure, and establish contact models between the outer wall of the casing and the inner wall of the cement sheath, and between the outer wall of the cement sheath and the inner wall of the formation, all set as surface-to-surface contact relationships. Add contact attributes, including normal and tangential forces between the contact surfaces. The normal contact attribute is hard contact, meaning that the magnitude of the contact pressure that can be transmitted between the contact surfaces is unlimited; the tangential contact attribute is Coulomb friction, that is, using the coefficient of friction to represent the frictional characteristics between the contact surfaces, which can be expressed as:

[0072] τ=μ×p

[0073] In the formula, τ is the shear stress near the street, μ is the friction coefficient, and p is the normal contact pressure.

[0074] ④ Four analysis steps are set up to calculate the comprehensive stress of the casing during fracturing. Analysis step 1 is set as a static analysis step to perform in-situ stress balance on the casing-cement sheath-formation composite model; analysis step 2 is set as a static analysis step to simulate the effect of formation slip on the casing and perform static analysis; analysis step 3 is a dynamic analysis step to simulate the pressure alternation process inside the casing during fracturing operations and perform dynamic analysis.

[0075] ⑤ Apply the corresponding loads and boundary condition constraints in each analysis step. In analysis step 1, apply an initial stress field to the model, including the maximum horizontal stress, minimum horizontal stress, and vertical stress; apply fixed constraints in the x-direction to the planes at both ends of the model, fixed constraints in the y-direction to the planes at the front and rear of the model, and fully fixed constraints to the bottom of the model. In analysis step 2, apply displacement loads along the formation slip direction to the model by creating boundary conditions. In analysis step 3, apply internal pressure loads to the inner surface of the casing, and simulate the fracturing process by defining a load change time history curve.

[0076] ⑥ Divide the casing and cement sheath into two parts using a central plane, and mesh them using three-dimensional eight-node hexahedral solid elements. Distribute 16 elements circumferentially, 2 elements radially, and 40 elements along the length of the casing and cement sheath cross-section. Refine the formation so that it can be meshed using three-dimensional eight-node hexahedral solid elements. The seeding density on the cross-section should be 1-2m, and the seeding density along the length of the casing should be 3-4m.

[0077] ⑦ The equivalent stress and displacement of the casing are calculated, and their dynamic changes during the fracturing process are determined.

[0078] This invention conducts joint simulation mechanical response analysis of fracturing casing in 3D well groups using different software. It considers both the influence of stress disturbance between wells in the 3D well group and the alternating load effect inside the casing during fracturing operations. Through detailed analysis from the overall to the local, it can accurately calculate the circumferential stress, radial stress, axial stress, and equivalent stress of the casing at each well location during the fracturing operation of the 3D well group, and determine the casing deformation law and the magnitude of the deformation. It is a complete mechanical analysis process for 3D well group casing, which is of great significance for carrying out research on the integrity of fracturing casing in shale oil 3D well groups. At the same time, it can provide a reference for predicting the casing deformation location and deformation during the fracturing process of 3D well groups, so as to prevent and reduce the casing damage risk in actual fracturing operations.

[0079] Beneficial effects: Based on the geomechanical simulation model of a three-dimensional well group, this invention determines the changes in formation stress and displacement before and after fracturing operations, and then establishes a near-wellbore geomechanical simulation model of the three-dimensional well group. It calculates the equivalent stress of the casing, formation stress, and formation displacement at each well location, and determines the location with the maximum equivalent stress of the casing as the casing danger zone. Furthermore, it establishes a local three-dimensional finite element simulation model of the casing-cement sheath-formation at the casing danger zone, uses the formation stress at this location calculated above as the initial stress field, uses the formation displacement at this location as the external displacement boundary condition, and applies internal temperature and pressure loads to the casing according to the fracturing operation parameters to calculate the magnitude of casing stress and deformation law during fracturing operations.

[0080] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for modeling and analyzing the mechanical response of fracturing casing in a three-dimensional well group, characterized in that, The modeling and analysis methods include: Three-dimensional geomechanical modeling of the entire well group was carried out to obtain a three-dimensional geomechanical model; Based on the aforementioned three-dimensional geomechanical model, near-wellbore geomechanical modeling is performed to obtain the near-wellbore model; Two studies were set up to solve the near-wellbore model.

2. The method for modeling and analyzing the mechanical response of fracturing casing in a three-dimensional well group according to claim 1, characterized in that, The specific steps of performing three-dimensional geomechanical modeling of the entire well group area include: A three-dimensional well group basic database within the block was constructed, and structural modeling, lithofacies modeling, and reservoir property modeling were performed to obtain a three-dimensional geomechanical model of the block. Based on the fracturing design scheme developed by the three-dimensional well group, the fracturing construction process of the three-dimensional well group is simulated to generate an unstructured mesh and hydraulic fracture network after fracturing. This is then transformed into a new hydraulic fracture network that includes the pressure within the fracture, which is used to solve the formation stress field and displacement field after fracturing. Simulation data of formation displacement and stress distribution after fracturing are obtained and compared with the formation displacement and stress distribution before fracturing.

3. The method for modeling and analyzing the mechanical response of fracturing casing in a three-dimensional well group according to claim 1, characterized in that, The near-wellbore geomechanical modeling based on the aforementioned three-dimensional geomechanical model specifically includes: Based on the full-area three-dimensional geomechanical model of shale oil well groups, near-wellbore geomechanical models for various well locations were established, and corresponding mechanical material properties of casing, cement sheath and near-wellbore formation were added to obtain near-wellbore geomechanical models with added mechanical material properties. The model is added with formation displacement fields before and after fracturing as boundary conditions for near-wellbore mechanical simulation analysis. The stress, strain and displacement changes of casing, cement sheath and near-wellbore formation under various well locations are solved to determine the casing locations with the maximum casing stress and formation displacement in each well location in the three-dimensional well group, which are regarded as the dangerous areas of wellbore structure.

4. The method for modeling and analyzing the mechanical response of fracturing casing in a three-dimensional well group according to claim 1, characterized in that, The specific steps for solving the near-wellbore model using two studies include: Based on the structural parameters of the casing, cement sheath, and formation near the wellbore in the structurally hazardous area, a local three-dimensional finite element simulation model of the casing-cement sheath-formation was established. Material properties are added to the three-dimensional finite element simulation model, and the contact relationships between the casing-cement sheath and the cement sheath-formation are set. The formation stress in the near-wellbore model analysis results is set as the external load of the local model, and the formation displacement is set as the external boundary condition of the local model. The internal pressure and temperature loads of the casing are set according to the fracturing construction parameters of the three-dimensional well group. The dynamic changes of casing stress and deformation during the fracturing construction of the three-dimensional well group are solved, and the strength verification and structural integrity analysis of the fracturing casing are performed.

5. The method for modeling and analyzing the mechanical response of fracturing casing in a three-dimensional well group according to claim 1, characterized in that, The basic database of the three-dimensional well group specifically includes: well location coordinates, well inclination, wellbore trajectory, drilling stratification, logging data, and breakpoint data.

6. The method for modeling and analyzing the mechanical response of fracturing casing in a three-dimensional well group according to claim 3, characterized in that, When establishing near-wellbore geomechanical models for various well locations, homogeneous modeling is adopted, and the casing, cement sheath, and near-wellbore formation materials are all single-layer homogeneous materials.

7. The method for modeling and analyzing the mechanical response of fracturing casing in a three-dimensional well group according to claim 1, characterized in that, The specific steps of performing three-dimensional geomechanical modeling of the entire well group area include: Set up meshes for overlying, underlying, and lateral rock layers. The overlying rock layers generally extend to the ground surface. When extending the underlying rock layers, the depth should ensure that the entire model has a suitable aspect ratio. Extend the lateral rock layer mesh by extending to a specified distance or by a specified multiple. Add planes to the outer layer of the lateral mesh to ensure uniform application of boundary conditions. The planes should be set to rigid. Establish the constitutive relations of the material and determine that the rock is an anisotropic Mohr-Coulomb constitutive model, with the following relations: In the formula, R mc It is a measure of the shape of the yield surface on the π plane; is the soil friction angle, i.e., the inclination angle of the Mohr-Coulomb yield surface on the qp surface; C is the soil cohesion, MPa; Input crack data, determine crack strength curves, perform crack direction analysis, and realize a discrete crack network model; By setting the number of fracturing stages and the displacement parameters, a three-dimensional well group fracturing simulation of shale oil was conducted to obtain the formation stress field and displacement field after fracturing.

8. The method for modeling and analyzing the mechanical response of fracturing casing in a three-dimensional well group according to claim 1, characterized in that, The near-wellbore geomechanical modeling based on the aforementioned three-dimensional geomechanical model specifically includes: Determine the top and bottom depths of the near-wellbore model. For casing completion, the top depth starts from the wellhead. The near-wellbore model is established based on cylindrical coordinates. After determining the inner and outer boundaries of the model, the number of meshes in the tangential, radial, and axial directions is input to complete the mesh generation. After establishing the near-wellbore model mesh, mechanical modeling was performed, and the geomechanical simulation parameters of the rock were set respectively. The mud density was set according to the actual drilling parameters. Add mechanical parameters for the sleeve and cement ring.

9. The method for modeling and analyzing the mechanical response of fracturing casing in a three-dimensional well group according to claim 8, characterized in that, The specific geomechanical simulation parameters of the rock include Young's modulus, Poisson's ratio, rock strength, pore pressure, geostress, and mud density.

10. The method for modeling and analyzing the mechanical response of fracturing casing in a three-dimensional well group according to claim 8, characterized in that, The mechanical parameters of the casing and cement ring specifically include: elastic parameters, casing strength, cement ring strength, and density.

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