Evaluation method of the effect of pile insertion on the stability of large diameter steel cylinders in jack-up drilling vessels

Abstract

The present invention discloses a method for evaluating the influence of pile insertion of a jack-up drilling ship on the stability of a large-diameter steel cylinder, including: establishing soil components, steel cylinder components, and pile shoe components; assigning material section properties to the three components; obtaining an assembly model; creating a gravity analysis step and a load analysis step; setting the contact properties between the soil and the steel cylinder, setting boundary conditions; meshing; applying gravity and pile shoe penetration loads, and establishing a three-dimensional finite element numerical simulation model, etc. The present invention discloses a method for evaluating the influence of pile insertion of a jack-up drilling ship on the stability of a large-diameter steel cylinder, and establishes a practical engineering numerical simulation calculation method, which can effectively evaluate the influence of pile insertion of a drilling ship on the stability of an adjacent steel cylinder under different working conditions, and promotes the progress of the analysis technology of large deformation engineering problems of marine rock and soil.

Description

Technical Field

[0001] The invention relates to a numerical simulation analysis method for large deformation of marine rock and soil, and in particular to an evaluation method for the influence of pile insertion of a jack-up drilling ship on the stability of a large-diameter steel cylinder. Background Art

[0002] my country's Bohai Sea navigation area is rich in oil and gas resources. Considering the safety of navigation and underwater facilities, it is necessary to use protective structures under the seabed mud surface to protect the underwater production system to ensure the safe operation of oil and gas fields. At present, the underwater protective structure is a large-diameter thin-walled steel cylinder. Usually, self-elevating drilling platforms are used for drilling and well repair operations in the Bohai Sea oil and gas fields. Due to the limited length of the drilling platform's operating arm, the distance between the platform pile shoe and the steel cylinder may be relatively close. During the process of the pile shoe being inserted into place, the surrounding soil undergoes great plastic deformation, which in turn squeezes the adjacent steel cylinder structure. Under the action of the soil squeezing force, the steel cylinder produces uncertain stress and deformation, which seriously affects its safety and stability. Therefore, it is necessary to evaluate the impact of pile insertion by a self-elevating drilling ship on the stability of the steel cylinder.

[0003] During the pile insertion process of the jack-up drilling vessel, the surrounding soil undergoes great plastic deformation, which is a typical large deformation problem of marine rock and soil. Usually, when the soil deformation is extremely large, the conventional small strain Lagrangian finite element method has serious mesh distortion and cannot be effectively solved. However, the Coupled Eulerian-Lagrangian (CEL) method, which can effectively simulate large deformation of rock and soil, has a small stable time increment in simulation calculation and a high computing time cost due to the thin wall thickness of the steel cylinder. Therefore, it is necessary to improve the existing numerical simulation method to improve the calculation efficiency and ensure the accuracy of the calculation results. Summary of the invention

[0004] The purpose of the present invention is to provide an evaluation method for the influence of pile insertion of a jack-up drilling ship on the stability of a large-diameter thin-walled steel cylinder. The influence of pile insertion of a drilling ship on the stability of a large-diameter thin-walled steel cylinder is studied by numerical simulation using ABAQUS finite element software. The CEL algorithm is used to analyze the movement of the surrounding soil and the stress, strain and deformation of the steel cylinder during the pile shoe penetration process, thereby ensuring the calculation efficiency and the accuracy of the calculation results, and providing a basis for the stability evaluation of the large-diameter thin-walled steel cylinder during the pile shoe penetration process of the drilling ship.

[0005] The present invention provides a method for evaluating the influence of pile insertion of a jack-up drilling ship on the stability of a large-diameter steel cylinder, comprising:

[0006] Using ABAQUS finite element software, according to the size of the pile shoe and the steel cylinder and the distance between the edge of the pile shoe and the edge of the steel cylinder, the soil component, the steel cylinder component and the pile shoe component are established respectively, wherein the soil component includes a cavity;

[0007] According to the soil parameters of the oil and gas field and the material parameters of the steel cylinder and pile shoe, the cross-sectional properties of the materials of the three components, namely the soil component, the steel cylinder component and the pile shoe component, are assigned;

[0008] According to the distance between the pile shoe and the steel cylinder, the soil component, the steel cylinder component and the pile shoe component and the cross-sectional properties of the materials of the respective components are assembled to obtain an assembly model;

[0009] According to the assembly model, create a gravity analysis step and a load analysis step;

[0010] Setting the contact properties between the soil and the steel cylinder of the assembly model and setting the boundary conditions;

[0011] Meshing the assembly model according to the components;

[0012] Gravity is applied in the gravity analysis step, and the pile shoe penetration load is applied in the load analysis step, so as to establish a complete three-dimensional finite element numerical simulation model;

[0013] Submit the three-dimensional finite element numerical simulation model, select the double-precision calculation mode, and calculate the stress, strain and deformation of the large-diameter steel cylinder during the drilling ship pile shoe penetration process;

[0014] The cloud charts of the calculated results of stress, strain and deformation of the steel cylinder during the penetration of the drilling ship pile shoe are analyzed to determine the changing rules of the calculated results of stress, strain and deformation of the steel cylinder at different penetration depths.

[0015] Preferably, a cavity at a certain height is arranged above the soil of the soil component, and the interior of the steel cylinder is arranged as a cavity.

[0016] Preferably, the soil and the cavity are Eulerian materials, and their respective material properties are given by an initial predefined field.

[0017] Preferably, the gravity analysis step and the load analysis step are created by using an explicit dynamic algorithm, soil stress equilibrium is performed in the gravity analysis step, and pile shoe penetration analysis is performed in the load analysis step.

[0018] Preferably, a universal contact is set between the steel cylinder and the soil body; and a velocity boundary and an Euler non-reflection boundary are set on the bottom and side surfaces of the Euler soil body in the assembly model.

[0019] Preferably, the soil in the area where the pile shoe is located is set to a fine grid, and the soil in the area outside the pile shoe is set to a grid from dense to sparse.

[0020] The invention also discloses a device for measuring the influence of pile insertion of a self-elevating drilling ship on the stability of a large-diameter steel cylinder, comprising:

[0021] The first processing unit is used to use ABAQUS finite element software to respectively establish a soil component, a steel cylinder component and a pile shoe component according to the sizes of the pile shoe and the steel cylinder and the distance between the edge of the pile shoe and the edge of the steel cylinder, wherein the soil component includes a cavity;

[0022] The second processing unit is used to assign cross-sectional properties of the materials of the soil component, the steel cylinder component and the pile shoe component according to the soil parameters of the oil and gas field site and the material parameters of the steel cylinder and the pile shoe;

[0023] The third processing unit is used to assemble the soil component, the steel cylinder component and the pile shoe component and the cross-sectional properties of the materials of the respective components according to the distance between the pile shoe and the steel cylinder to obtain an assembly model;

[0024] A fourth processing unit, used for creating a gravity analysis step and a load analysis step according to the assembly model;

[0025] a fifth processing unit, used to set the contact properties between the soil and the steel cylinder of the assembly model and to set the boundary conditions;

[0026] A sixth processing unit, configured to perform grid division on the assembly model according to the components;

[0027] A seventh processing unit is used to apply gravity in the gravity analysis step and apply the pile shoe penetration load in the load analysis step, so as to establish a complete three-dimensional finite element numerical simulation model;

[0028] An eighth processing unit is used to submit the three-dimensional finite element numerical simulation model, select a double-precision calculation mode, and calculate the stress, strain, and deformation of the large-diameter steel cylinder during the drilling ship pile shoe penetration process;

[0029] The ninth processing unit is used to analyze the cloud diagram of the calculation results of the stress, strain and deformation of the steel cylinder during the penetration of the drilling ship pile shoe, and determine the change law of the calculation results of the stress, strain and deformation of the steel cylinder at different penetration depths.

[0030] The present invention also discloses a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned evaluation method are implemented.

[0031] The present invention also discloses a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned evaluation method when executing the computer program.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention discloses a method for evaluating the influence of pile insertion by a jack-up drilling ship on the stability of a large-diameter steel cylinder: the large-deformation finite element method of rock and soil is adopted, the large-diameter steel cylinder is regarded as a shell, and Lagrangian materials are adopted; the soil is regarded as a solid, and Euler materials are adopted; the pile shoe is regarded as a rigid body, and no deformation is generated during the calculation process. The large-diameter steel cylinder is discretized into shell units, and the soil is discretized into Euler units. The double-precision mode is used to calculate the cylinder stress and deformation of the steel cylinder during the penetration of the drilling ship pile shoe into the soil, and then the stability of the steel cylinder is accurately evaluated. The method for evaluating the influence of pile insertion by a jack-up drilling ship on the stability of a large-diameter steel cylinder disclosed by the present invention establishes a practical engineering numerical simulation calculation method, which can quickly evaluate the degree of influence of the drilling ship pile insertion on the adjacent steel cylinder under different working conditions, and promotes the progress of the analysis technology of large-deformation engineering problems in marine rock and soil. DETAILED DESCRIPTION

[0034] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0035] Example 1

[0036] Example 1 provides a method for evaluating the effect of pile insertion of a jack-up drilling ship on the stability of a large-diameter steel cylinder, the evaluation method comprising the following steps:

[0037] Step A: Using ABAQUS finite element software, according to the size of the pile shoe and the steel cylinder and the distance between the edge of the pile shoe and the edge of the steel cylinder, three parts are established, namely: soil part, steel cylinder part, and pile shoe part. Among them, the soil part includes cavities, and Euler materials are used to simulate soil and cavities, rigid bodies are used to simulate pile shoes, and shells are used to simulate large-diameter steel cylinders.

[0038] Euler materials are used to simulate soil and cavities. The reason is that the pile shoe of the jack-up drilling platform penetrates deep into the soil layer, causing large deformation of the surrounding soil. The grid nodes and material points of conventional Lagrangian materials are shared. When the soil deformation is large, the grid is severely distorted and the calculation results cannot converge. The grid nodes and material points of Euler materials are separated from each other. When the material is deformed, the material points flow in the grid, which can effectively simulate and solve the problem of extremely large deformation of the soil.

[0039] The length of the horizontal long side of the soil and cavity parts is approximately twice the sum of the maximum cross-sectional size of the pile shoe, the minimum horizontal distance between the edge of the pile shoe and the edge of the steel cylinder, and the diameter of the steel cylinder; the length of the horizontal short side is approximately twice the sum of the maximum cross-sectional size of the pile shoe and the diameter of the steel cylinder.

[0040] A hole at a certain height is set above the soil because during the penetration of the pile shoe, the surrounding soil may bulge upward due to the squeezing force of the pile shoe. The hole provides sufficient flow space for the bulging soil to reveal the movement pattern of the soil. At the same time, the inside of the steel cylinder is set as a hole to simulate the hollowness of the steel cylinder.

[0041] Rigid bodies are used to simulate pile shoes. The reasons are as follows: compared with the stiffness and deformation of the soil, the stiffness of the pile shoes is large, and their deformation during the penetration process is very small and can be ignored. Secondly, the influence of the pile shoes on the stability of the steel cylinder during the penetration process mainly studies the plastic deformation of the surrounding soil and the deformation and stress of the steel cylinder under the action of the soil squeezing force, and does not focus on the deformation caused by the pile shoes. Therefore, in order to improve the calculation efficiency and save the calculation cost, the pile shoes are set as rigid bodies.

[0042] The three-dimensional deformable shell is used to simulate the large diameter steel cylinder because the ratio of the steel cylinder diameter to the wall thickness is very large (about 1000), which belongs to the thin-walled shell structure. At the same time, the three-dimensional shell simulation can effectively improve the calculation efficiency.

[0043] Step B: According to the soil parameters of the oil and gas field and the material parameters of the steel cylinder and pile shoe, the material section properties of the soil and cavity components, the steel cylinder components and the pile shoe components are established and assigned.

[0044] The soil and cavity are Eulerian materials, and their respective material properties are given by initial predefined fields;

[0045] Step C: assembling the soil and cavity components, the steel cylinder components and the pile shoe components according to the distance between the pile shoe and the steel cylinder;

[0046] Step D: Create gravity analysis step and load analysis step for the assembly model established in step C;

[0047] After the components are assembled, the explicit dynamics algorithm is used to create gravity analysis steps and load analysis steps. The soil stress balance is performed in the gravity analysis step, and the pile shoe penetration analysis is performed in the load analysis step.

[0048] Step E: for the assembly model in steps C and D, set the contact properties between the soil and the steel cylinder, and set the boundary conditions;

[0049] In the assembly model, a general contact is set between the steel cylinder and the soil; in the assembly model, velocity boundaries and Euler non-reflection boundaries are set on the bottom and side surfaces of the Euler soil.

[0050] Step F: Mesh the assembly models in steps C, D and E according to their components;

[0051] When meshing, a reasonable mesh size as well as coarse mesh and fine mesh areas should be determined.

[0052] The soil in the area where the pile shoe is located is set to a fine grid, and the soil in the area outside the pile shoe is set to a grid from dense to sparse;

[0053] Step G: Apply gravity in the gravity analysis step established in step D; apply the pile shoe penetration load in the load analysis step established in step D, and establish a complete three-dimensional finite element numerical simulation model.

[0054] Step H: After step G is completed, submit the three-dimensional finite element numerical simulation model, select the double-precision calculation mode, and calculate the stress, strain and deformation of the large-diameter steel cylinder during the drilling ship pile shoe penetration process;

[0055] The default calculation accuracy of ABAQUS finite element software is single precision. This method selects double precision to effectively calculate the stress, strain and deformation of the steel cylinder during the drilling ship pile insertion process.

[0056] Step I: After the calculation of step H is completed, the cloud diagram of the calculation results of stress, strain and deformation of the steel cylinder during the drilling ship pile shoe penetration process is analyzed to determine the change law of the calculation results of stress, strain and deformation of the steel cylinder at different penetration depths.

[0057] The present invention discloses a method for evaluating the influence of pile insertion of a jack-up drilling ship on the stability of a large-diameter steel cylinder. The method mainly adopts the following methods in the CEL finite element method: using Euler materials to simulate soil and cavities, using rigid bodies to simulate pile shoes, and using three-dimensional shells to simulate large-diameter steel cylinders. Double-precision algorithms are used to calculate the stress, strain and deformation of the steel cylinder during the penetration of the drilling ship pile shoes.

[0058] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A method for evaluating the effect of pile insertion on the stability of a large diameter steel cylinder by a jack-up drilling vessel, characterized in that: include: Using ABAQUS finite element software, according to the size of the pile shoe and the steel cylinder and the distance between the edge of the pile shoe and the edge of the steel cylinder, the soil component, the steel cylinder component and the pile shoe component are established respectively, wherein the soil component includes a cavity; According to the soil parameters of the oil and gas field and the material parameters of the steel cylinder and pile shoe, the cross-sectional properties of the materials of the three components, namely the soil component, the steel cylinder component and the pile shoe component, are assigned; According to the distance between the pile shoe and the steel cylinder, the soil component, the steel cylinder component and the pile shoe component and the cross-sectional properties of the materials of the respective components are assembled to obtain an assembly model; According to the assembly model, create a gravity analysis step and a load analysis step; Setting the contact properties between the soil and the steel cylinder of the assembly model and setting the boundary conditions; Meshing the assembly model according to the components; Gravity is applied in the gravity analysis step, and the pile shoe penetration load is applied in the load analysis step, so as to establish a complete three-dimensional finite element numerical simulation model; Submit the three-dimensional finite element numerical simulation model, select the double-precision calculation mode, and calculate the stress, strain and deformation of the large-diameter steel cylinder during the drilling ship pile shoe penetration process; The cloud charts of the calculated results of stress, strain and deformation of the steel cylinder during the penetration of the drilling ship pile shoe are analyzed to determine the changing rules of the calculated results of stress, strain and deformation of the steel cylinder at different penetration depths.

2. The evaluation method according to claim 1, characterized in that: A cavity at a certain height is arranged above the soil of the soil component, and the interior of the steel cylinder is arranged as a cavity.

3. The evaluation method according to claim 2, characterized in that: The soil and the cavity are Eulerian materials, and their respective material properties are given by an initial predefined field.

4. The evaluation method according to claim 1, characterized in that: The gravity analysis step and the load analysis step are created by using an explicit dynamic algorithm. The soil stress balance is performed in the gravity analysis step, and the pile shoe penetration analysis is performed in the load analysis step.

5. The evaluation method according to claim 1, characterized in that: A general contact is set between the steel cylinder and the soil; velocity boundaries and Euler non-reflection boundaries are set on the bottom and side of the Euler soil in the assembly model.

6. The evaluation method according to claim 1, characterized in that: The soil in the area where the pile shoe is located is set to a fine grid, and the soil in the area outside the pile shoe is set to a grid from dense to sparse.

7. A device for evaluating the effect of pile insertion on the stability of a large diameter steel cylinder of a jack-up drilling vessel, characterized in that: include The first processing unit is used to use ABAQUS finite element software to respectively establish a soil component, a steel cylinder component and a pile shoe component according to the sizes of the pile shoe and the steel cylinder and the distance between the edge of the pile shoe and the edge of the steel cylinder, wherein the soil component includes a cavity; The second processing unit is used to assign cross-sectional properties of the materials of the soil component, the steel cylinder component and the pile shoe component according to the soil parameters of the oil and gas field site and the material parameters of the steel cylinder and the pile shoe; The third processing unit is used to assemble the soil component, the steel cylinder component and the pile shoe component and the cross-sectional properties of the materials of the respective components according to the distance between the pile shoe and the steel cylinder to obtain an assembly model; A fourth processing unit, used for creating a gravity analysis step and a load analysis step according to the assembly model; a fifth processing unit, used to set the contact properties between the soil and the steel cylinder of the assembly model and to set the boundary conditions; A sixth processing unit, configured to perform grid division on the assembly model according to the components; A seventh processing unit is used to apply gravity in the gravity analysis step and apply the pile shoe penetration load in the load analysis step, so as to establish a complete three-dimensional finite element numerical simulation model; An eighth processing unit is used to submit the three-dimensional finite element numerical simulation model, select a double-precision calculation mode, and calculate the stress, strain, and deformation of the large-diameter steel cylinder during the drilling ship pile shoe penetration process; The ninth processing unit is used to analyze the cloud diagram of the calculation results of the stress, strain and deformation of the steel cylinder during the penetration of the drilling ship pile shoe, and determine the change law of the calculation results of the stress, strain and deformation of the steel cylinder at different penetration depths.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the evaluation method according to any one of claims 1 to 6 are implemented.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the evaluation method described in any one of claims 1 to 6 are implemented.