Method for predicting high-temperature fatigue life of rod body thread of aluminum alloy drill rod

Abstract

The invention relates to the technical field of aluminum alloy drill rods, in particular to an aluminum alloy drill rod body thread high-temperature fatigue life prediction method, which comprises the following steps: establishing a drill string dynamic model to obtain load spectrum initial data; establishing an aluminum alloy drill rod body thread thermal-mechanical coupling finite element model to obtain initial stress-strain distribution; performing a high-temperature fatigue test to obtain fatigue life data of the aluminum alloy material at different temperatures; establishing a high-temperature fatigue damage model; and constructing a high-temperature fatigue life prediction model based on the load spectrum initial data, the initial stress-strain distribution, the fatigue life data and the high-temperature fatigue damage model. Therefore, the problems that the fatigue failure mechanism of the aluminum alloy drill rod body thread in the high-temperature environment is not explored, the coupling effect of creep damage and fatigue damage is not fully considered, the influence rule of vibration load characteristics on the fatigue life and the failure mode is not clear, and engineering practice cannot be accurately guided are solved.

Description

Technical Field

[0001] The present application relates to the technical field of aluminum alloy drill rods, and in particular to a method for predicting the high-temperature fatigue life of aluminum alloy drill rod body threads. Background Art

[0002] With the growing demand for resources, my country has made significant progress in ultra-deep well engineering (≥6,000m), surpassing the United States in terms of number and setting a series of Asian drilling records, such as "Songke 2 Well" and "Pengshen 6 Well." However, the characteristics of ultra-deep wells, such as high well temperature, high pressure, long tubing, large wellbore diameter, and high corrosion, pose many challenges to drilling projects.

[0003] In related technologies, the minimum number of samples required under different coefficient of variation conditions can be calculated based on the confidence and error of the remaining service life prediction of the drill pipe, and the working load borne by the drill pipe during service can be calculated through sampling and processing, thereby obtaining the fatigue life. Fatigue tests can also be carried out with the empirical tensile strength as the test load to estimate the conditional fatigue limit strength, and the conditional fatigue limit strength under the specified life can be calculated by gradually increasing or decreasing the value as the loading load.

[0004] However, in the relevant technologies, there is a lack of in-depth research on the fatigue failure mechanism of aluminum alloy drill pipe body threads under high temperature environment, the coupling effect of creep damage and fatigue damage has not been fully considered, and the influence of vibration load characteristics on fatigue life and failure mode has not been clarified. It is impossible to accurately guide engineering practice and urgently needs improvement. Summary of the Invention

[0005] The present application provides a method for predicting the high-temperature fatigue life of aluminum alloy drill pipe body threads to address the problems in related technologies, such as the lack of research on the fatigue failure mechanism of aluminum alloy drill pipe body threads in high-temperature environments, the failure to fully consider the coupling effect of creep damage and fatigue damage, and the lack of clear influence of vibration load characteristics on fatigue life and failure mode, which cannot accurately guide engineering practice.

[0006] The first aspect of the present application provides a method for predicting the high-temperature fatigue life of an aluminum alloy drill pipe body thread, which is applied to a model building stage, wherein the method comprises the following steps: establishing a drill string dynamics model according to the aluminum alloy drill pipe drill string structure to obtain initial data of a load spectrum acting on a high-temperature fatigue test of the aluminum alloy drill pipe body thread; establishing a thermal-mechanical coupling finite element model of the aluminum alloy drill pipe body thread to obtain an initial stress-strain distribution of the aluminum alloy drill pipe body thread; performing a high-temperature fatigue test on the aluminum alloy material used for the aluminum alloy drill pipe body thread to obtain fatigue life data of the aluminum alloy material used at different temperatures; establishing a high-temperature fatigue damage model of the aluminum alloy material used based on the fatigue life data and continuous damage mechanics, wherein the high-temperature fatigue damage model includes creep damage evolution and fatigue damage evolution; and constructing a high-temperature fatigue life prediction model for predicting the high-temperature fatigue life of the aluminum alloy drill pipe body thread based on the initial data of the load spectrum, the initial stress-strain distribution, the fatigue life data, the creep damage evolution and the fatigue damage evolution in the high-temperature fatigue damage model.

[0007] Optionally, in one embodiment of the present application, the drill string dynamics model is a beam-shell combined unit model that takes temperature effects into account, wherein the drill string dynamics model is established based on the aluminum alloy drill pipe drill string structure, including: determining the contact state between the drill string and the well wall based on the target contact model; dividing the area between the drill string and the well wall into a first contact area and a second contact area based on the contact state, wherein the contact time between the drill string and the well wall in the first contact area is much greater than the contact time between the drill string and the well wall in the second contact area; constructing a shell unit model in the drill string dynamics model based on the first contact area; constructing a beam unit model in the drill string dynamics model based on the second contact area; combining the shell unit model and the beam unit model to construct a drill string grid model; and constructing the drill string dynamics model based on the drill string grid model and the Lagrange equation.

[0008] Optionally, in one embodiment of the present application, the mesh model of the aluminum alloy drill pipe body thread thermal-mechanical coupling finite element model may be, but is not limited to, a three-dimensional hexahedral mesh model, and the load boundary of the aluminum alloy drill pipe body thread thermal-mechanical coupling finite element model may be, but is not limited to, the initial load spectrum data of a single cycle obtained from the drill string dynamics model.

[0009] Optionally, in one embodiment of the present application, before performing a high-temperature fatigue test on the aluminum alloy material used for the aluminum alloy drill pipe body thread, the process further includes: collecting sample information of the aluminum alloy material subjected to the high-temperature fatigue test; determining temperature information of the aluminum alloy material subjected to the high-temperature fatigue test based on the sample information; and obtaining geometric information of the aluminum alloy drill pipe body thread and material information of the aluminum alloy material used based on the sample information.

[0010] Optionally, in one embodiment of the present application, a high-temperature fatigue damage model of the aluminum alloy material used is established based on the fatigue life data and continuous damage mechanics, wherein the high-temperature fatigue damage model includes creep damage evolution and fatigue damage evolution, including: based on the drill string dynamics model, extracting the longitudinal vibration load curve acting on the aluminum alloy drill pipe body thread; processing the longitudinal vibration load curve to obtain the load spectrum data required for the high-temperature fatigue test; using the load spectrum data to perform a high-temperature fatigue test on the aluminum alloy material used to obtain the creep evolution parameters of the creep damage evolution and the fatigue evolution parameters of the fatigue damage evolution.

[0011] Optionally, in one embodiment of the present application, the expression of the drill string dynamics model may be, but is not limited to:

[0012]

[0013] Among them, M is the overall mass matrix, C is the overall damping matrix, K(T) is the overall stiffness matrix, the stiffness matrix is a function of temperature, F is the external force on the whole, and u is the displacement matrix. is the velocity matrix, is the acceleration matrix.

[0014] Optionally, in one embodiment of the present application, the expression for creep damage evolution may be, but is not limited to:

[0015]

[0016] Where σ(t) is the stress per cycle that changes with time, t is time, and D c is creep damage, A is the inverse term parameter of stress on creep, r is the exponential term parameter of stress on creep, (1+r) is the multiplier term parameter of stress on creep, m1 is the influence parameter of the current cycle creep cumulative damage on the next cycle creep damage increment, dD c is the creep damage increment of a single cycle under high temperature creep;

[0017] The expression of fatigue damage evolution can be, but is not limited to:

[0018]

[0019] Among them, σ a is the stress amplitude, σ m is the mean stress, σ r is the average stress ratio, T is the temperature, D f is fatigue damage, B, C and E are weight coefficients of stress amplitude, mean stress and mean stress ratio respectively, M is the influencing parameter on stress amplitude, mean stress or mean stress ratio, N is fatigue life, β(T) is damage index, m2 is the influencing parameter of current cycle fatigue cumulative damage on next cycle fatigue damage increment, dD f It is the fatigue damage increment of a single cycle under mechanical fatigue.

[0020] Optionally, in one embodiment of the present application, the expression of the high temperature fatigue damage model may be, but is not limited to:

[0021] dD=f(dD c ,dD f ),

[0022] Among them, dD is the damage increment of a single cycle under the combined action of high-temperature creep and mechanical fatigue. When damage does not occur, D = 0. When D accumulates to 1, failure occurs.

[0023] A second aspect embodiment of the present application provides a method for predicting the high-temperature fatigue life of an aluminum alloy drill pipe body thread, which is applied to a model application stage, wherein the method comprises the following steps: obtaining actual temperature information of an actual aluminum alloy drill pipe body thread and actual drill string motion state information; inputting the actual temperature information and the actual drill string motion state information into a pre-constructed high-temperature fatigue life prediction model to obtain a high-temperature fatigue life prediction result of the actual aluminum alloy drill pipe body thread, wherein the pre-constructed high-temperature fatigue life prediction model is obtained from a high-temperature fatigue damage model.

[0024] In a third aspect, an embodiment of the present application provides a device for predicting the high-temperature fatigue life of an aluminum alloy drill pipe body thread, which is applied to a model building stage, wherein the device comprises: a first building module for establishing a drill string dynamics model according to the aluminum alloy drill pipe drill string structure to obtain initial load spectrum data acting on a high-temperature fatigue test of the aluminum alloy drill pipe body thread; a second building module for establishing a thermal-mechanical coupling finite element model of the aluminum alloy drill pipe body thread to obtain the initial stress-strain distribution of the aluminum alloy drill pipe body thread; a test module for performing a high-temperature fatigue test on the aluminum alloy material used for the aluminum alloy drill pipe body thread , to obtain fatigue life data of the aluminum alloy material used at different temperatures; a third construction module is used to establish a high-temperature fatigue damage model of the aluminum alloy material used based on the fatigue life data and continuous damage mechanics, wherein the high-temperature fatigue damage model includes creep damage evolution and fatigue damage evolution; a fourth construction module is used to construct a high-temperature fatigue life prediction model for predicting the high-temperature fatigue life of the aluminum alloy drill pipe body thread based on the initial load spectrum data, the initial stress-strain distribution, fatigue life data, creep damage evolution and fatigue damage evolution in the high-temperature fatigue damage model.

[0025] Optionally, in one embodiment of the present application, the drill string dynamics model is a beam-shell combination unit model that takes temperature influence into account, wherein the first construction module includes: a determination unit for determining the contact state between the drill string and the well wall according to a target contact model; a division unit for dividing the area between the drill string and the well wall into a first contact area and a second contact area according to the contact state, wherein the contact time between the drill string and the well wall in the first contact area is much greater than the contact time between the drill string and the well wall in the second contact area; a first construction unit for constructing a shell unit model in the drill string dynamics model based on the first contact area; a second construction unit for constructing a beam unit model in the drill string dynamics model based on the second contact area; a third construction unit for combining the shell unit model and the beam unit model to construct a drill string grid model; and a fourth construction unit for constructing the drill string dynamics model based on the drill string grid model and the Lagrange equation.

[0026] Optionally, in one embodiment of the present application, the mesh model of the aluminum alloy drill pipe body thread thermal-mechanical coupling finite element model may be, but is not limited to, a three-dimensional hexahedral mesh model, and the load boundary of the aluminum alloy drill pipe body thread thermal-mechanical coupling finite element model may be, but is not limited to, the initial load spectrum data of a single cycle obtained from the drill string dynamics model.

[0027] Optionally, in one embodiment of the present application, it further includes: an acquisition module for acquiring sample information of the aluminum alloy material subjected to a high-temperature fatigue test before the aluminum alloy material used for the aluminum alloy drill pipe body thread is subjected to a high-temperature fatigue test; a determination module for determining temperature information of the aluminum alloy material subjected to the high-temperature fatigue test based on the sample information; and a first acquisition module for acquiring geometric information of the aluminum alloy drill pipe body thread and material information of the aluminum alloy material used based on the sample information.

[0028] Optionally, in one embodiment of the present application, the third building module includes: an extraction unit for extracting the longitudinal vibration load curve acting on the thread of the aluminum alloy drill pipe body based on the drill string dynamics model; a processing unit for processing the longitudinal vibration load curve to obtain the load spectrum data required for the high temperature fatigue test; and a generation unit for using the load spectrum data to perform a high temperature fatigue test on the aluminum alloy material used to obtain the creep evolution parameters of the creep damage evolution and the fatigue evolution parameters of the fatigue damage evolution.

[0029] Optionally, in one embodiment of the present application, the expression of the drill string dynamics model may be, but is not limited to:

[0030]

[0031] Among them, M is the overall mass matrix, C is the overall damping matrix, K(T) is the overall stiffness matrix, the stiffness matrix is a function of temperature, F is the external force on the whole, and u is the displacement matrix. is the velocity matrix, is the acceleration matrix.

[0032] Optionally, in one embodiment of the present application, the expression for creep damage evolution may be, but is not limited to:

[0033]

[0034] Where σ(t) is the stress per cycle that changes with time, t is time, and D c is creep damage, A is the inverse term parameter of stress on creep, r is the exponential term parameter of stress on creep, (1+r) is the multiplier term parameter of stress on creep, m1 is the influence parameter of the current cycle creep cumulative damage on the next cycle creep damage increment, dD c is the creep damage increment of a single cycle under high temperature creep;

[0035] The expression of fatigue damage evolution can be, but is not limited to:

[0036]

[0037] Among them, σ a is the stress amplitude, σ m is the mean stress, σ r is the average stress ratio, T is the temperature, D f is fatigue damage, B, C and E are weight coefficients of stress amplitude, mean stress and mean stress ratio respectively, M is the influencing parameter on stress amplitude, mean stress or mean stress ratio, N is fatigue life, β(T) is damage index, m2 is the influencing parameter of current cycle fatigue cumulative damage on next cycle fatigue damage increment, dD f It is the fatigue damage increment of a single cycle under mechanical fatigue.

[0038] Optionally, in one embodiment of the present application, the expression of the high temperature fatigue damage model may be, but is not limited to:

[0039] dD=f(dD c ,dD f ),

[0040] Among them, dD is the damage increment of a single cycle under the combined action of high-temperature creep and mechanical fatigue. When damage does not occur, D = 0. When D accumulates to 1, failure occurs.

[0041] The fourth aspect of the present application provides a high-temperature fatigue life prediction device for an aluminum alloy drill pipe body thread, which is applied to a model application stage, wherein the device includes: a second acquisition module for acquiring actual temperature information and actual drill string motion state information of an actual aluminum alloy drill pipe body thread; a prediction module for inputting the actual temperature information and the actual drill string motion state information into a pre-constructed high-temperature fatigue life prediction model to obtain a high-temperature fatigue life prediction result of the actual aluminum alloy drill pipe body thread, wherein the pre-constructed high-temperature fatigue life prediction model is obtained from a high-temperature fatigue damage model.

[0042] A fifth aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for predicting the high-temperature fatigue life of the aluminum alloy drill pipe body thread as described in the above embodiment.

[0043] A sixth aspect of the present application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned method for predicting the high-temperature fatigue life of the thread of an aluminum alloy drill pipe body.

[0044] A seventh aspect of the present application provides a computer program product, including a computer program, which, when executed, implements the above-mentioned method for predicting the high-temperature fatigue life of the thread of the aluminum alloy drill pipe body.

[0045] The embodiment of the present application can use the drill string dynamics model to obtain the initial data of the load spectrum, use the thermal-mechanical coupling finite element model to obtain the initial stress-strain distribution, and conduct high-temperature fatigue tests to obtain fatigue life data at different temperatures, and then establish a high-temperature fatigue damage model, so as to construct a high-temperature fatigue life prediction model using the initial data of the load spectrum, the initial stress-strain distribution, the fatigue life data, and the high-temperature fatigue damage model. By establishing a high-temperature fatigue damage model from a microscopic level, considering the damage evolution process inside the material, coupling creep damage and fatigue damage, and describing the changes in the microstructure of the material during high-temperature fatigue, the high-temperature fatigue life prediction model can more accurately reflect the damage accumulation and failure process of the material at the microscopic scale. The fatigue failure mechanism of the aluminum alloy drill pipe body thread under high-temperature environment is deeply studied, which provides a more solid theoretical basis for the safe application of aluminum alloy drill pipe in ultra-deep wells, and provides more reliable technical support and theoretical supplement for ultra-deep well drilling projects. This solves the problems in related technologies, such as the lack of research on the fatigue failure mechanism of aluminum alloy drill pipe body threads in high temperature environments, the failure to fully consider the coupling effect of creep damage and fatigue damage, the lack of clear influence of vibration load characteristics on fatigue life and failure mode, and the inability to accurately guide engineering practice.

[0046] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0048] Figure 1 This is a flow chart of a method for predicting high-temperature fatigue life of aluminum alloy drill pipe body threads according to an embodiment of the present application;

[0049] Figure 2 A block diagram of a drill string dynamics model provided according to one embodiment of the present application;

[0050] Figure 3 A schematic block diagram of a three-dimensional hexahedral mesh model provided according to one embodiment of the present application;

[0051] Figure 4 A flowchart of a thermal-mechanical coupling finite element model calculation according to one embodiment of the present application;

[0052] Figure 5A flowchart of constructing a high-temperature fatigue life prediction model according to one embodiment of the present application;

[0053] Figure 6 This is a block diagram of a device for predicting the high-temperature fatigue life of an aluminum alloy drill pipe body thread according to an embodiment of the present application;

[0054] Figure 7 This is a flow chart of a method for predicting high-temperature fatigue life of aluminum alloy drill pipe body threads according to another embodiment of the present application;

[0055] Figure 8 This is a block diagram of a device for predicting high-temperature fatigue life of aluminum alloy drill pipe body threads according to another embodiment of the present application;

[0056] Figure 9 A schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0057] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0058] The following describes the high-temperature fatigue life prediction method for aluminum alloy drill pipe body threads in the embodiment of the present application with reference to the accompanying drawings. In response to the problem mentioned in the above background technology that there is a lack of research on the fatigue failure mechanism of aluminum alloy drill pipe body threads in high temperature environments, the coupling effect of creep damage and fatigue damage is not fully considered, and the influence of vibration load characteristics on fatigue life and failure mode is not clarified, and engineering practice cannot be accurately guided, the present application provides a high-temperature fatigue life prediction method for aluminum alloy drill pipe body threads. In this method, the drill string dynamics model can be used to obtain the initial data of the load spectrum, the thermal-mechanical coupling finite element model can be used to obtain the initial stress-strain distribution, and high-temperature fatigue tests can be carried out to obtain fatigue life data at different temperatures, and then a high-temperature fatigue damage model can be established, so that the initial data of the load spectrum can be used to obtain the initial stress-strain distribution. The high-temperature fatigue life prediction model is constructed by combining initial data, initial stress-strain distribution, fatigue life data, and high-temperature fatigue damage model. By establishing a high-temperature fatigue damage model at the microscopic level, considering the damage evolution process inside the material, coupling creep damage and fatigue damage, and describing the changes in the material microstructure during high-temperature fatigue, the high-temperature fatigue life prediction model can more accurately reflect the damage accumulation and failure process of the material at the microscopic scale. The fatigue failure mechanism of aluminum alloy drill pipe body threads under high-temperature environments is deeply studied, providing a more solid theoretical foundation for the safe application of aluminum alloy drill pipes in ultra-deep wells, and providing more reliable technical support and theoretical supplements for ultra-deep well drilling projects. As a result, the problems in related technologies such as the lack of research on the fatigue failure mechanism of aluminum alloy drill pipe body threads under high-temperature environments, the failure to fully consider the coupling effect of creep damage and fatigue damage, and the failure to clarify the influence of vibration load characteristics on fatigue life and failure mode, which cannot accurately guide engineering practice, are solved.

[0059] Specifically, Figure 1 The present invention provides a flowchart of a method for predicting the high-temperature fatigue life of aluminum alloy drill pipe body threads according to an embodiment of the present application.

[0060] like Figure 1 As shown, the high-temperature fatigue life prediction method for aluminum alloy drill pipe body threads is applied in the model building stage, wherein the method includes the following steps:

[0061] In step S101, a drill string dynamics model is established according to the aluminum alloy drill pipe drill string structure to obtain initial load spectrum data acting on a high temperature fatigue test of an aluminum alloy drill pipe body thread.

[0062] In some embodiments, the embodiments of the present application can study the influence of the longitudinal vibration of the drill string on the high-temperature fatigue failure mechanism of the aluminum alloy drill pipe body thread. By establishing a beam-shell combined unit model, the Lagrange equation is used to obtain the unit dynamic equation and integrate it to obtain the dynamic equation of the drill string dynamic model. At the same time, a target contact model of the drill string and the well wall is established, and the drill string dynamic model is solved using an explicit dynamic algorithm. The motion characteristics of the drill string are analyzed, and the longitudinal vibration load curve acting on the aluminum alloy drill pipe body thread is extracted. The longitudinal vibration load characteristics at different positions from the vibration source are analyzed, and the rain flow counting method is used to process the longitudinal vibration load curve to obtain the load spectrum, thereby providing accurate load spectrum initial data for subsequent high-temperature fatigue tests on the aluminum alloy drill pipe body thread.

[0063] Among them, in the embodiments of the present application, the longitudinal vibration load characteristics may include but are not limited to the maximum stress amplitude, average stress, average stress ratio, etc., and the present application does not impose specific restrictions.

[0064] For example, the embodiment of the present application can obtain the overall drill string vibration parameters according to the aluminum alloy drill pipe drill string structure, establish a drill string dynamics model, and obtain the initial load spectrum data. The schematic diagram of the drill string dynamics model is as follows: Figure 2 shown.

[0065] The embodiment of the present application establishes a drill string dynamics model, analyzes the influence of factors such as rotational speed, bit pressure, friction coefficient and the gap between the drill string and the well wall on the vortex state of the drill string, and studies the influence of the position, temperature, rotation speed and other factors of the aluminum alloy drill rod on the vortex of the drill string, thereby providing overall load boundary conditions for subsequent analysis; when analyzing the influence of the longitudinal vibration of the drill string on the fatigue life of the thread, the transmission law of the vibration load at different positions is studied, the longitudinal vibration load characteristics are determined, and a macro-level input is provided for the local thread analysis.

[0066] Optionally, in one embodiment of the present application, the drill string dynamics model is a beam-shell combined unit model that takes temperature effects into account, wherein the drill string dynamics model is established based on the aluminum alloy drill pipe drill string structure, including: determining the contact state between the drill string and the wellbore wall based on the target contact model; dividing the area between the drill string and the wellbore wall into a first contact area and a second contact area based on the contact state, wherein the contact time between the drill string and the wellbore wall in the first contact area is much greater than the contact time between the drill string and the wellbore wall in the second contact area; constructing a shell unit model in the drill string dynamics model based on the first contact area; constructing a beam unit model in the drill string dynamics model based on the second contact area; combining the shell unit model and the beam unit model to construct a drill string mesh model; and constructing the drill string dynamics model based on the drill string mesh model and the Lagrange equation. The expression of the drill string dynamics model may be, but is not limited to,:

[0067]

[0068] Among them, M is the overall mass matrix, C is the overall damping matrix, K(T) is the overall stiffness matrix, the stiffness matrix is a function of temperature, F is the external force on the whole, and u is the displacement matrix. is the velocity matrix, is the acceleration matrix.

[0069] In some embodiments, to balance calculation speed and accuracy, the present invention uses shell elements for modeling in the first contact area and beam elements for modeling in the second contact area. A drill string mesh model is then established, and the Lagrange equations are used to derive the dynamic equations for the shell element model and the beam element model. These equations are then combined to construct a drill string dynamic model. The expression for the drill string dynamic model may be, but is not limited to, the following:

[0070]

[0071] Among them, M is the overall mass matrix, C is the overall damping matrix, K(T) is the overall stiffness matrix, the stiffness matrix is a function of temperature, F is the external force on the whole, and u is the displacement matrix. is the velocity matrix, is the acceleration matrix.

[0072] In the embodiment of the present application, the first contact area and the second contact area can be determined by the target contact model. It can be understood that the embodiment of the present application can judge the contact state between the well wall and the drill string by the distance between the well wall and the drill string: when the well wall and the drill string are not in contact, d n >0; when the well wall contacts the drill string, d n =0(where d n is the normal distance between the well wall and the drill string), wherein the contact time between the drill string and the well wall in the first contact area is much greater than the contact time between the drill string and the well wall in the second contact area.

[0073] In addition, it should be noted that the embodiments of the present application can use an explicit dynamics algorithm to solve the drill string dynamics model and analyze the drill string motion characteristics under different working conditions.

[0074] In the embodiment of the present application, at the macro scale, the drill string dynamics model adopts a beam-shell combined unit model, and the Lagrange equation is used to obtain the dynamic equations of the shell unit model and the beam unit model, and they are combined to obtain the dynamic equations of the drill string dynamics model. At the same time, the contact state between the drill string and the well wall is determined through the target contact model, and the explicit dynamics algorithm is used to solve the drill string dynamics model and analyze the drill string motion characteristics.

[0075] In step S102, a thermal-mechanical coupling finite element model of the aluminum alloy drill pipe body threads is established to obtain the initial stress and strain distribution of the aluminum alloy drill pipe body threads. The mesh model of the thermal-mechanical coupling finite element model of the aluminum alloy drill pipe body threads may be, but is not limited to, a three-dimensional hexahedral mesh model, and the load boundary of the thermal-mechanical coupling finite element model of the aluminum alloy drill pipe body threads may be, but is not limited to, initial load spectrum data from a single cycle obtained from the drill string dynamics model.

[0076] In some embodiments, the process of establishing the three-dimensional hexahedral mesh model of the embodiment of the present application can be: through the mathematical description of the thread profile, a piecewise function of the thread profile is obtained, the profile is modeled based on the MATLAB software using a loop algorithm and node and unit information is assigned to obtain the hexahedral mesh information of the threaded portion, and then based on the end face features of the threaded portion, the shoulder, thread retraction transition portion and rod portion are described by function, and node and unit information are assigned, and finally a three-dimensional hexahedral mesh model that can accurately describe the geometric characteristics of the thread is established, as shown in the schematic diagram. Figure 3 shown.

[0077] In some embodiments, the process of establishing the thermomechanical coupling finite element model of the embodiment of the present application can be as follows: considering the actual environment and stress conditions of the aluminum alloy drill pipe body thread in the ultra-deep well, a thermomechanical coupling finite element model is established, wherein the embodiment of the present application can use constants to describe the density and thermal conductivity (because they are basically stable at different temperatures), and write the elastic modulus and elastoplastic constitutive model of the aluminum alloy as a function of temperature to reflect the nonlinear and thermomechanical coupling properties of the material. A full coupling method is used for coupling calculation, the mechanical control equation is established based on the principle of virtual work, the contact heat transfer process is determined by the contact state, the nonlinear contact heat transfer equation is derived, and the penalty function is used to solve the contact equation. Finally, the thermomechanical coupling implicit dynamics algorithm is used to perform numerical calculations on the thermomechanical coupling finite element model to analyze the initial stress and strain distribution under the combined action of high temperature and longitudinal vibration load.

[0078] In addition, it should be noted that in the embodiment of the present application, the load boundary of the thermal-mechanical coupling finite element model can be, but is not limited to, the initial load spectrum data of a single cycle obtained from the drill string dynamics model, and the present application does not impose any specific restrictions.

[0079] For example, the embodiments of the present application are combined with Figure 4 As shown in the figure, the calculation process of the thermal-mechanical coupling finite element model is introduced.

[0080] Step S401: Drill pipe joint parameters are input.

[0081] Step S402: Generate a network in MATLAB.

[0082] Step S403: Outputting the mesh file of the tool joint.

[0083] Step S404: Import the grid file.

[0084] Step S405: Input material parameters.

[0085] Step S406: Create a cross section.

[0086] Step S407: Analysis step.

[0087] Step S408: Loading and boundary condition input.

[0088] Step S409: Calculation.

[0089] Step S410: Output the result.

[0090] In the embodiments of the present application, an accurate three-dimensional hexahedral mesh model is established for the thread at the mesoscopic scale, and the complex contact nonlinearity and material nonlinearity of the threaded connection are taken into account to study the initial stress-strain distribution of the thread under high temperature and longitudinal vibration load; by conducting high-temperature fatigue tests and orthogonal high-temperature fatigue tests, the influence of factors such as temperature, stress ratio, and stress amplitude on the fatigue life and failure mode of the thread is analyzed, the fatigue failure mechanism of the thread in the local area is studied, and the creep damage evolution and fatigue damage evolution are revealed.

[0091] Optionally, in one embodiment of the present application, before performing a high-temperature fatigue test on the aluminum alloy material used for the aluminum alloy drill pipe body thread, the process further includes: collecting sample information of the aluminum alloy material undergoing the high-temperature fatigue test; determining temperature information of the aluminum alloy material undergoing the high-temperature fatigue test based on the sample information; and obtaining geometric information of the aluminum alloy drill pipe body thread and material information of the aluminum alloy material used based on the sample information.

[0092] In some embodiments, the embodiments of the present application can sample from the vicinity of the aluminum alloy drill pipe body thread to determine the aluminum alloy material used for the aluminum alloy drill pipe body thread, and then obtain sample information corresponding to the high-temperature fatigue test of the aluminum alloy material based on the aluminum alloy material, and use XRD to obtain material information of the aluminum alloy material used, such as the type of internal elements and the content of each element, etc., which is not specifically limited in this application, and use a metallographic microscope to observe the geometric information of the aluminum alloy drill pipe body thread, such as eutectic silicon, dendrites, various metal compounds, pores and casting defects, etc., which is not specifically limited in this application, to provide material information for the aluminum alloy material used in subsequent research.

[0093] In addition, the embodiment of the present application conducts a high-temperature fatigue test within the temperature range in which the aluminum alloy material used undergoes high-temperature fatigue, and the temperature range can be 388K to 433K. The specific setting can be made by technicians in this field according to actual conditions, and this application does not impose any specific restrictions.

[0094] For example, the embodiment of the present application takes 2024 aluminum alloy drill pipe as an example. Its initial melting point is 775K (502°C), the permissible temperature is 433K (160°C), and the temperature at which high-temperature fatigue occurs is 388K (115°C). Therefore, the embodiment of the present application can select a range of 388K-20K to 433K+20K for high-temperature fatigue testing to better study the influence of temperature on the fatigue life of the aluminum alloy drill pipe body thread. Among them, ±20K can be understood as the temperature range can be offset by 20K above and below 388K, and by 20K above and below 433K. This application does not impose specific restrictions.

[0095] Illustratively, the embodiment of the present application can determine the aluminum alloy material used for the aluminum alloy drill rod body thread based on the interference fit between the aluminum alloy drill rod body thread and the steel joint, and obtain sample information of the high-temperature fatigue test of the aluminum alloy material used, and then conduct a high-temperature fatigue test on the aluminum alloy material used to obtain fatigue life data at different temperatures, and at the same time analyze the cyclic stress-strain curve, and use a scanning electron microscope and a transmission electron microscope to perform microscopic analysis on the fracture of the failed sample, observe the microscopic characteristics, study the high-temperature fatigue failure mechanism, and explore the creep damage evolution and fatigue damage evolution.

[0096] In step S103, a high temperature fatigue test is performed on the aluminum alloy material used for the threads of the aluminum alloy drill pipe body to obtain fatigue life data of the aluminum alloy material at different temperatures.

[0097] In some embodiments, the high-temperature fatigue test of the aluminum alloy material used in the aluminum alloy drill rod body thread of the embodiment of the present application is used to obtain fatigue life data of the aluminum alloy material used at different temperatures, which can be used for parameter fitting of the fatigue damage formula and creep damage formula in the high-temperature fatigue damage model.

[0098] Among them, the high-temperature fatigue test in the embodiment of the present application may include but is not limited to an orthogonal high-temperature fatigue test and a high-temperature fatigue test, which can be specifically set by technicians in this field according to actual conditions, and this application does not impose any specific restrictions.

[0099] Among them, in the orthogonal high temperature fatigue test of the embodiment of the present application, a 5-factor 4-level orthogonal table can be selected for test design, as shown in Table 1. The main contents can be: selecting the maximum stress amplitude, average stress, average stress ratio and temperature as influencing factors, selecting appropriate differences to establish the number of levels (such as taking 4 levels as an example, this application does not make specific restrictions), and carrying out orthogonal high temperature fatigue tests with fatigue life as the evaluation index. Selecting a 5-factor 4-level orthogonal table (such as L 16 (4 5), not specifically limited in this application, experimental design was conducted. Range analysis, variance analysis, and error analysis were performed based on the experimental results to study the influence of various factors on fatigue life, explore the primary factors affecting high-temperature fatigue life, and provide a theoretical basis for optimizing drilling parameters. Table 1 is a table of factor levels based on orthogonal high-temperature fatigue testing, provided according to one embodiment of this application.

[0100] Table 1

[0101]

[0102] Furthermore, the embodiment of the present application conducts a high-temperature fatigue test on the aluminum alloy material used based on a 5-factor 4-level orthogonal table, and its fatigue life data is shown in Table 2, wherein Table 2 is a schematic table of fatigue life data of the orthogonal high-temperature fatigue test of the aluminum alloy material provided according to one embodiment of the present application.

[0103] Table 2

[0104]

[0105]

[0106] The embodiment of the present application conducts high-temperature fatigue tests on the aluminum alloy material used for the aluminum alloy drill pipe body thread, obtains fatigue life data of the aluminum alloy material at different temperatures, analyzes the influence of temperature on fatigue life and cyclic stress-strain curves, explores the influence of temperature on cyclic soft hardening, and provides parameter support for modeling.

[0107] In step S104, a high-temperature fatigue damage model of the aluminum alloy material is established based on fatigue life data and continuum damage mechanics, wherein the high-temperature fatigue damage model includes creep damage evolution and fatigue damage evolution.

[0108] In some embodiments, the embodiments of the present application can use scanning electron microscopy and transmission electron microscopy to perform microscopic analysis on the fracture of each sample, explore the creep damage evolution and fatigue damage evolution under longitudinal vibration load, and establish creep and fatigue damage evolution formulas respectively, establish a high-temperature fatigue damage model, calculate the total damage increment, and determine failure when the total damage increment reaches 1; based on the results of high-temperature fatigue tests and orthogonal high-temperature fatigue tests of materials, the parameters in the high-temperature fatigue damage model are fitted and solved, and the high-temperature fatigue damage model is written into a script program, and iterative calculations are performed based on the initial stress-strain distribution to predict the fatigue life of the aluminum alloy drill pipe body thread.

[0109] At the microscopic scale, the embodiments of the present application can establish a high-temperature fatigue damage model based on continuum damage mechanics at the microscopic level, consider the damage evolution process inside the aluminum alloy material used, couple creep damage and fatigue damage, and describe the changes in the microstructure of the material during the high-temperature fatigue test; observe the microscopic characteristics of the fracture and the changes in the microstructure through microanalysis technology, determine the microscopic parameters in the high-temperature fatigue damage model, and enable the high-temperature fatigue life prediction model to more accurately reflect the damage accumulation and failure process of the material at the microscopic scale.

[0110] Among them, when observing the microscopic characteristics of the fracture and the changes in microstructure through microscopic analysis technology, the embodiments of the present application can use technical means such as scanning electron microscopy and transmission electron microscopy to compare the distribution characteristics of the fracture morphology, brittle fracture surface, microcracks, tearing edges and dimples, as well as the appearance of dislocations and subgrain boundaries, and explore the coupling effect of creep damage and fatigue damage under longitudinal vibration load from a microscopic perspective, providing theoretical support for the determination of high-temperature fatigue life prediction model parameters.

[0111] Optionally, in one embodiment of the present application, a high-temperature fatigue damage model for the aluminum alloy material used is established based on fatigue life data and continuous damage mechanics, wherein the high-temperature fatigue damage model includes creep damage evolution and fatigue damage evolution, including: extracting the longitudinal vibration load curve acting on the aluminum alloy drill pipe body thread based on the drill string dynamics model; processing the longitudinal vibration load curve to obtain the load spectrum data required for high-temperature fatigue testing; and using the load spectrum data to perform a high-temperature fatigue test on the aluminum alloy material used to obtain creep evolution parameters for creep damage evolution and fatigue evolution parameters for fatigue damage evolution. The expression for creep damage evolution can be, but is not limited to,:

[0112]

[0113] Where σ(t) is the stress per cycle that changes with time, t is time, and D c is creep damage, A is the inverse term parameter of stress on creep, r is the exponential term parameter of stress on creep, (1+r) is the multiplier term parameter of stress on creep, m1 is the influence parameter of the current cycle creep cumulative damage on the next cycle creep damage increment, dD c is the creep damage increment of a single cycle under high temperature creep;

[0114] The expression of fatigue damage evolution can be, but is not limited to:

[0115]

[0116] Among them, σ a is the stress amplitude, σ m is the mean stress, σ r is the average stress ratio, T is the temperature, Df is fatigue damage, B, C and E are weight coefficients of stress amplitude, mean stress and mean stress ratio respectively, M is the influencing parameter on stress amplitude, mean stress or mean stress ratio, N is fatigue life, β(T) is damage index, m2 is the influencing parameter of current cycle fatigue cumulative damage on next cycle fatigue damage increment, dD f It is the fatigue damage increment of a single cycle under mechanical fatigue.

[0117] The expression of high temperature fatigue damage model can be but not limited to:

[0118] dD=f(dD c ,dD f ),

[0119] Among them, dD is the damage increment of a single cycle under the combined action of high-temperature creep and mechanical fatigue. When damage does not occur, D = 0. When D accumulates to 1, failure occurs.

[0120] In some embodiments, the embodiments of the present application can use the drill string dynamics model to extract the longitudinal vibration load curve acting on the aluminum alloy drill pipe body thread, and process the longitudinal vibration load curve to obtain the load spectrum data required for the high-temperature fatigue test, and obtain the creep evolution parameters of the creep damage evolution and the initial fatigue evolution parameters of the fatigue damage evolution after the high-temperature fatigue test.

[0121] In the embodiment of the present application, the general expression of creep damage evolution can be, but is not limited to,:

[0122] dD c =f c (σ(t),T,D c )dt,

[0123] Among them, σ(t) is the stress that changes with time in each cycle, t is time, which will affect the material parameters in the model, D c It is creep damage.

[0124] Furthermore, in the embodiment of the present application, taking into account the nonlinearity of continuum damage mechanics and the influence of temperature on material properties, the specific expression of creep damage evolution can be, but is not limited to:

[0125]

[0126] Where σ(t) is the stress per cycle that changes with time, t is time, and D c is creep damage, A is the inverse term parameter of stress on creep, r is the exponential term parameter of stress on creep, (1+r) is the multiplier term parameter of stress on creep, m1 is the influence parameter of the current cycle creep cumulative damage on the next cycle creep damage increment, dDc is the creep damage increment of a single cycle under high temperature creep.

[0127] It can be seen from this that the creep damage increment in the embodiment of the present application is related to stress, temperature, material properties and creep cumulative damage.

[0128] In the embodiment of the present application, the general expression of fatigue damage evolution can be, but is not limited to:

[0129] dD f =f f (σ a ,σ m2 ,σ r ,T,D f )dN,

[0130] Among them, σ a is the stress amplitude, σ m2 is the mean stress, σ r is the average stress ratio, T is the temperature, which will affect the material parameters in the model, D f It is fatigue damage.

[0131] Furthermore, the embodiment of the present application is based on the classic fatigue damage model proposed by Lemaitre et al. Since the embodiment of the present application adds the influence of mean stress and mean stress ratio, an improved fatigue damage model is proposed. The specific expression of fatigue damage evolution can be, but is not limited to:

[0132]

[0133] Among them, σ a is the stress amplitude, σ m is the mean stress, σ r is the average stress ratio, T is the temperature, D f is fatigue damage, B, C and E are weight coefficients of stress amplitude, mean stress and mean stress ratio respectively, M is the influencing parameter on stress amplitude, mean stress or mean stress ratio, N is fatigue life, β(T) is the damage index, which is used to consider the effect of temperature change, m2 is the influencing parameter of the current cycle fatigue cumulative damage on the next cycle fatigue damage increment, dD f It is the fatigue damage increment of a single cycle under mechanical fatigue.

[0134] Furthermore, the embodiment of the present application takes into account the combined effect of fatigue damage and creep damage on the total damage amount. Therefore, the expression of the high temperature fatigue damage model can be, but is not limited to,:

[0135] dD=f(dD c ,dD f ),

[0136] Among them, dD is the damage increment of a single cycle under the combined action of high-temperature creep and mechanical fatigue. When damage does not occur, D = 0. When D accumulates to 1, failure occurs.

[0137] For example, the embodiment of the present application can be fitted according to the data in Table 2 to obtain the values of parameters A, r, m1, m2, B, C, E, M, and β(T), and their values can be: A=443.22979660772404, r=0.00705325180155316, m1=m2=113.14983852592127, B=0.47210734929832116, C=0.4691152459324417, E=-54.120298750690544, M=41687.64302531112, β(T)=-112.92006587577892, thereby obtaining a high-temperature fatigue damage model and completing the microscopic high-temperature fatigue damage mechanics description.

[0138] In step S105, a high temperature fatigue life prediction model for predicting the high temperature fatigue life of aluminum alloy drill pipe body threads is constructed based on the initial load spectrum data, initial stress-strain distribution, fatigue life data, creep damage evolution and fatigue damage evolution in the high temperature fatigue damage model.

[0139] As a possible implementation method, the embodiment of the present application can comprehensively consider the initial data of the load spectrum, the initial stress-strain distribution, the fatigue life data, the creep damage evolution and the fatigue damage evolution, etc. when constructing a high-temperature fatigue life prediction model for predicting the high-temperature fatigue life of the aluminum alloy drill pipe body thread. This application does not impose any specific restrictions.

[0140] It can be understood that the embodiment of the present application obtains fatigue life data of aluminum alloy materials based on high-temperature fatigue tests, fits and solves various parameters of the high-temperature fatigue damage model, determines appropriate fatigue parameters, and writes the derived high-temperature fatigue damage model into a script program. Iterative calculations are performed based on the initial data of the load spectrum, the initial stress-strain distribution, and the fatigue life data to construct a high-temperature fatigue life prediction model. The high-temperature fatigue life prediction model can reveal the fatigue life and dangerous areas of the aluminum alloy drill pipe body thread, and explore the influence of different parameters on fatigue life and methods to improve fatigue life.

[0141] For example, combined Figure 5 As shown, the process of the high temperature fatigue life prediction model in the embodiment of the present application can be:

[0142] Step S501: extracting a longitudinal vibration load curve acting on the threads of the aluminum alloy drill pipe body.

[0143] Step S502: Process the longitudinal vibration load curve using the rain flow counting method to obtain a load spectrum.

[0144] Step S503: Obtain load boundaries at different temperatures.

[0145] In the embodiment of the present application, the load boundary may be, but is not limited to, initial load spectrum data of a single cycle obtained from a drill string dynamics model.

[0146] Step S504: establishing a mesh model of the thermal-mechanical coupling finite element model.

[0147] In the embodiment of the present application, the mesh model of the thermal-mechanical coupling finite element model may be, but is not limited to, a three-dimensional hexahedral mesh model.

[0148] Step S505: Calculate the initial stress and strain distribution of the aluminum alloy drill pipe body thread using a thermal-mechanical coupling finite element model.

[0149] Step S506: using the drill string dynamics model to obtain initial load spectrum data for the high-temperature fatigue test on the aluminum alloy material.

[0150] Step S507: performing a high temperature fatigue test.

[0151] Step S508: Acquire the creep damage evolution and fatigue damage evolution of the aluminum alloy drill material and construct a high-temperature fatigue damage model.

[0152] Step S509: fitting and solving the parameters in the high temperature fatigue damage model.

[0153] Step S510: performing iterative calculations to construct a high-temperature fatigue life prediction model.

[0154] Among them, the embodiment of the present application obtains fatigue life data of aluminum alloy materials based on high-temperature fatigue tests, fits and solves various parameters of the high-temperature fatigue damage model, determines appropriate fatigue parameters, and writes the derived high-temperature fatigue damage model into a script program. Iterative calculations are performed based on the initial data of the load spectrum, the initial stress-strain distribution, and the fatigue life data to construct a high-temperature fatigue life prediction model.

[0155] According to the high-temperature fatigue life prediction method for aluminum alloy drill pipe body threads proposed in the embodiment of the present application, the drill string dynamics model can be used to obtain initial load spectrum data, the thermal-mechanical coupling finite element model can be used to obtain initial stress-strain distribution, and high-temperature fatigue tests can be performed to obtain fatigue life data at different temperatures, and then a high-temperature fatigue damage model can be established. The high-temperature fatigue life prediction model is constructed using the initial load spectrum data, initial stress-strain distribution, fatigue life data, and high-temperature fatigue damage model. By establishing a high-temperature fatigue damage model at a microscopic level, the damage evolution process inside the material is considered, creep damage and fatigue damage are coupled, and the changes in the microstructure of the material during the high-temperature fatigue process are described, so that the high-temperature fatigue life prediction model more accurately reflects the damage accumulation and failure process of the material at the microscopic scale. The fatigue failure mechanism of the aluminum alloy drill pipe body threads under high-temperature environments is deeply studied, which provides a more solid theoretical basis for the safe application of aluminum alloy drill pipes in ultra-deep wells and provides more reliable technical support and theoretical supplements for ultra-deep well drilling projects. This solves the problems in related technologies, such as the lack of research on the fatigue failure mechanism of aluminum alloy drill pipe body threads in high temperature environments, the failure to fully consider the coupling effect of creep damage and fatigue damage, the lack of clear influence of vibration load characteristics on fatigue life and failure mode, and the inability to accurately guide engineering practice.

[0156] Next, a device for predicting the high-temperature fatigue life of aluminum alloy drill rod body threads according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0157] Figure 6 The present invention is a block diagram of a device for predicting the high-temperature fatigue life of an aluminum alloy drill pipe body thread according to an embodiment of the present application.

[0158] like Figure 6 As shown, the aluminum alloy drill pipe body thread high temperature fatigue life prediction device 60 is applied to the model construction stage, wherein the device 60 includes: a first construction module 601, a second construction module 602, a test module 603, a third construction module 604 and a fourth construction module 605.

[0159] The first building module 601 is used to establish a drill string dynamics model according to the aluminum alloy drill pipe drill string structure to obtain initial load spectrum data acting on the high temperature fatigue test of the aluminum alloy drill pipe body thread.

[0160] The second building module 602 is used to establish a thermal-mechanical coupling finite element model of the aluminum alloy drill pipe body thread to obtain the initial stress and strain distribution of the aluminum alloy drill pipe body thread.

[0161] The test module 603 is used to perform a high temperature fatigue test on the aluminum alloy material used for the aluminum alloy drill pipe body thread to obtain fatigue life data of the aluminum alloy material used at different temperatures.

[0162] The third building module 604 is used to establish a high-temperature fatigue damage model of the aluminum alloy material used based on fatigue life data and continuum damage mechanics, wherein the high-temperature fatigue damage model includes creep damage evolution and fatigue damage evolution.

[0163] The fourth construction module 605 is used to construct a high-temperature fatigue life prediction model for predicting the high-temperature fatigue life of the aluminum alloy drill pipe body thread based on the initial load spectrum data, the initial stress-strain distribution, the fatigue life data, the creep damage evolution and the fatigue damage evolution in the high-temperature fatigue damage model.

[0164] Optionally, in one embodiment of the present application, the drill string dynamics model is a beam-shell combination unit model that takes temperature effects into account, wherein the first construction module 601 includes: a determination unit, a division unit, a first construction unit, a second construction unit, a third construction unit, and a fourth construction unit.

[0165] The determination unit is used to determine the contact state between the drill string and the well wall according to the target contact model.

[0166] The dividing unit is used to divide the area between the drill string and the well wall into a first contact area and a second contact area according to the contact state, wherein the contact time between the drill string and the well wall in the first contact area is much longer than the contact time between the drill string and the well wall in the second contact area.

[0167] The first construction unit is used to construct a shell element model in the drill string dynamics model based on the first contact area.

[0168] The second construction unit is used to construct a beam unit model in the drill string dynamics model based on the second contact area.

[0169] The third construction unit is used to combine the shell element model and the beam element model to construct a drill string mesh model.

[0170] The fourth construction unit is used to construct a drill string dynamics model based on the drill string grid model and the Lagrange equation.

[0171] Optionally, in one embodiment of the present application, the mesh model of the thermal-mechanical coupling finite element model of the aluminum alloy drill pipe body thread may be, but is not limited to, a three-dimensional hexahedral mesh model, and the load boundary of the thermal-mechanical coupling finite element model of the aluminum alloy drill pipe body thread may be, but is not limited to, the initial load spectrum data of a single cycle obtained from the drill string dynamics model.

[0172] Optionally, in one embodiment of the present application, it further includes: a collection module, a determination module and a first acquisition module.

[0173] The acquisition module is used to collect sample information of the high-temperature fatigue test of the aluminum alloy material used for the aluminum alloy drill rod body thread before the high-temperature fatigue test is performed on the aluminum alloy material.

[0174] The determination module is used to determine the temperature information of the aluminum alloy material undergoing high temperature fatigue test based on the sample information.

[0175] The first acquisition module is used to acquire geometric information of the aluminum alloy drill rod body thread and material information of the aluminum alloy material used based on the sample information.

[0176] Optionally, in one embodiment of the present application, the third construction module 604 includes: an extraction unit, a processing unit, and a generation unit.

[0177] The extraction unit is used to extract the longitudinal vibration load curve acting on the thread of the aluminum alloy drill pipe body based on the drill string dynamics model.

[0178] The processing unit is used to process the longitudinal vibration load curve to obtain the load spectrum data required for high temperature fatigue testing.

[0179] The generating unit is used to perform a high temperature fatigue test on the aluminum alloy material used by using the load spectrum data to obtain creep evolution parameters of creep damage evolution and fatigue evolution parameters of fatigue damage evolution.

[0180] Optionally, in one embodiment of the present application, the expression of the drill string dynamics model may be, but is not limited to:

[0181]

[0182] Among them, M is the overall mass matrix, C is the overall damping matrix, K(T) is the overall stiffness matrix, the stiffness matrix is a function of temperature, F is the external force on the whole, and u is the displacement matrix. is the velocity matrix, is the acceleration matrix.

[0183] Optionally, in one embodiment of the present application, the expression for creep damage evolution may be, but is not limited to:

[0184]

[0185] Where σ(t) is the stress per cycle that changes with time, t is time, and D c is creep damage, A is the inverse term parameter of stress on creep, r is the exponential term parameter of stress on creep, (1+r) is the multiplier term parameter of stress on creep, m1 is the influence parameter of the current cycle creep cumulative damage on the next cycle creep damage increment, dD cis the creep damage increment of a single cycle under high temperature creep;

[0186] The expression of fatigue damage evolution can be, but is not limited to:

[0187]

[0188] Among them, σ a is the stress amplitude, σ m is the mean stress, σ r is the average stress ratio, T is the temperature, D f is fatigue damage, B, C and E are weight coefficients of stress amplitude, mean stress and mean stress ratio respectively, M is the influencing parameter on stress amplitude, mean stress or mean stress ratio, N is fatigue life, β(T) is damage index, m2 is the influencing parameter of current cycle fatigue cumulative damage on next cycle fatigue damage increment, dD f It is the fatigue damage increment of a single cycle under mechanical fatigue.

[0189] Optionally, in one embodiment of the present application, the expression of the high temperature fatigue damage model may be, but is not limited to:

[0190] dD=f(dD c ,dD f ),

[0191] Among them, dD is the damage increment of a single cycle under the combined action of high-temperature creep and mechanical fatigue. When damage does not occur, D = 0. When D accumulates to 1, failure occurs.

[0192] It should be noted that the above explanation of the embodiment of the method for predicting the high-temperature fatigue life of aluminum alloy drill pipe body threads is also applicable to the device for predicting the high-temperature fatigue life of aluminum alloy drill pipe body threads of this embodiment, and will not be repeated here.

[0193] According to the high-temperature fatigue life prediction device for aluminum alloy drill pipe body threads proposed in the embodiment of the present application, the drill string dynamics model can be used to obtain initial load spectrum data, the thermal-mechanical coupling finite element model can be used to obtain initial stress-strain distribution, and high-temperature fatigue tests can be performed to obtain fatigue life data at different temperatures, and then a high-temperature fatigue damage model can be established. The high-temperature fatigue life prediction model is constructed using the initial load spectrum data, initial stress-strain distribution, fatigue life data, and high-temperature fatigue damage model. By establishing a high-temperature fatigue damage model from a microscopic level, the damage evolution process inside the material is considered, creep damage and fatigue damage are coupled, and the changes in the microstructure of the material during the high-temperature fatigue process are described, so that the high-temperature fatigue life prediction model more accurately reflects the damage accumulation and failure process of the material at the microscopic scale. The fatigue failure mechanism of the aluminum alloy drill pipe body threads under high-temperature environments is deeply studied, which provides a more solid theoretical basis for the safe application of aluminum alloy drill pipes in ultra-deep wells and provides more reliable technical support and theoretical supplements for ultra-deep well drilling projects. This solves the problems in related technologies, such as the lack of research on the fatigue failure mechanism of aluminum alloy drill pipe body threads in high temperature environments, the failure to fully consider the coupling effect of creep damage and fatigue damage, the lack of clear influence of vibration load characteristics on fatigue life and failure mode, and the inability to accurately guide engineering practice.

[0194] The above embodiment describes the model building stage. The following describes an embodiment of the model application stage.

[0195] Figure 7 The present invention is a flowchart of a method for predicting the high-temperature fatigue life of aluminum alloy drill pipe body threads according to another embodiment of the present application.

[0196] like Figure 7 As shown, the high-temperature fatigue life prediction method for aluminum alloy drill pipe body threads is applied in the model application stage, wherein the method includes the following steps:

[0197] In step S701, actual temperature information of the actual aluminum alloy drill rod body thread and actual drill string motion state information are obtained.

[0198] In step S702, the actual temperature information and the actual drill string motion state information are input into a pre-built high-temperature fatigue life prediction model to obtain a high-temperature fatigue life prediction result of the actual aluminum alloy drill pipe body thread, wherein the pre-built high-temperature fatigue life prediction model is obtained from a high-temperature fatigue damage model.

[0199] As a possible implementation method, the embodiment of the present application can obtain the actual temperature information of the aluminum alloy drill pipe body thread and the actual drill string motion state information, and input the actual temperature information and the actual drill string motion state information into a pre-built high-temperature fatigue life prediction model to obtain a high-temperature fatigue life prediction result. Among them, the embodiment of the present application obtains load spectrum data through the drill string dynamics model, and the load spectrum data acts on the thermal-mechanical coupling finite element model. The initial stress distribution obtained by the thermal-mechanical coupling finite element model is used as the initial condition of the high-temperature fatigue damage model to calculate the fatigue life, thereby obtaining a high-temperature fatigue life prediction result.

[0200] According to the high-temperature fatigue life prediction method for aluminum alloy drill pipe body threads proposed in the embodiments of the present application, the actual temperature information of the aluminum alloy drill pipe body threads and the actual drill string motion state information obtained can be input into a pre-built high-temperature fatigue life prediction model, thereby obtaining the high-temperature fatigue life prediction result of the actual aluminum alloy drill pipe body threads. By establishing a high-temperature fatigue damage model at the microscopic level, considering the damage evolution process within the material, coupling creep damage and fatigue damage, and describing the changes in the material microstructure during the high-temperature fatigue process, the high-temperature fatigue life prediction model more accurately reflects the damage accumulation and failure process of the material at the microscale. The fatigue failure mechanism of aluminum alloy drill pipe body threads under high-temperature environments is deeply studied, providing a more solid theoretical foundation for the safe application of aluminum alloy drill pipes in ultra-deep wells and providing more reliable technical support and theoretical supplements for ultra-deep well drilling projects. Thus, the present invention solves the problems in the related art of the lack of research on the fatigue failure mechanism of aluminum alloy drill pipe body threads under high-temperature environments, the lack of sufficient consideration of the coupling effect of creep damage and fatigue damage, and the lack of clear rules on the influence of vibration load characteristics on fatigue life and failure mode, which cannot accurately guide engineering practice.

[0201] Next, a device for predicting the high-temperature fatigue life of aluminum alloy drill rod body threads according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0202] Figure 9 The present invention is a block diagram of a device for predicting high-temperature fatigue life of aluminum alloy drill pipe body threads according to another embodiment of the present application.

[0203] like Figure 8 As shown, the aluminum alloy drill pipe body thread high temperature fatigue life prediction device 80 is applied in the model application stage, wherein the device 80 includes: a second acquisition module 801 and a prediction module 802.

[0204] The second acquisition module 801 is used to acquire actual temperature information of the aluminum alloy drill rod body thread and actual drill string motion state information.

[0205] The prediction module 802 is used to input the actual temperature information and the actual drill string motion state information into a pre-built high-temperature fatigue life prediction model to obtain a high-temperature fatigue life prediction result of the actual aluminum alloy drill pipe body thread, wherein the pre-built high-temperature fatigue life prediction model is obtained from the high-temperature fatigue damage model.

[0206] It should be noted that the above explanation of the embodiment of the method for predicting the high-temperature fatigue life of aluminum alloy drill pipe body threads is also applicable to the device for predicting the high-temperature fatigue life of aluminum alloy drill pipe body threads of this embodiment, and will not be repeated here.

[0207] According to the high-temperature fatigue life prediction device for aluminum alloy drill pipe body threads proposed in the embodiments of the present application, the actual temperature information of the aluminum alloy drill pipe body threads and the actual drill string motion state information obtained can be input into a pre-built high-temperature fatigue life prediction model, thereby obtaining the high-temperature fatigue life prediction result of the actual aluminum alloy drill pipe body threads. By establishing a high-temperature fatigue damage model at the microscopic level, considering the damage evolution process within the material, coupling creep damage and fatigue damage, and describing the changes in the material microstructure during the high-temperature fatigue process, the high-temperature fatigue life prediction model more accurately reflects the damage accumulation and failure process of the material at the microscale. The fatigue failure mechanism of aluminum alloy drill pipe body threads under high-temperature environments is deeply studied, providing a more solid theoretical foundation for the safe application of aluminum alloy drill pipes in ultra-deep wells and providing more reliable technical support and theoretical supplements for ultra-deep well drilling projects. Thus, the present invention solves the problems in the related art of the lack of research on the fatigue failure mechanism of aluminum alloy drill pipe body threads under high-temperature environments, the lack of sufficient consideration of the coupling effect of creep damage and fatigue damage, and the lack of clear rules on the influence of vibration load characteristics on fatigue life and failure mode, which cannot accurately guide engineering practice.

[0208] Figure 9 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. The electronic device may include:

[0209] A memory 901 , a processor 902 , and a computer program stored in the memory 901 and executable on the processor 902 .

[0210] When the processor 902 executes the program, the high-temperature fatigue life prediction method for the aluminum alloy drill pipe body thread provided in the above embodiment is implemented.

[0211] Furthermore, the electronic device further includes:

[0212] The communication interface 903 is used for communication between the memory 901 and the processor 902 .

[0213] The memory 901 is used to store computer programs that can be run on the processor 902 .

[0214] The memory 901 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0215] If the memory 901, processor 902, and communication interface 903 are implemented independently, the communication interface 903, memory 901, and processor 902 can be interconnected via a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 9 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0216] Optionally, in a specific implementation, if the memory 901, the processor 902 and the communication interface 903 are integrated on a chip, the memory 901, the processor 902 and the communication interface 903 can communicate with each other through an internal interface.

[0217] The processor 902 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0218] An embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the above-mentioned method for predicting the high-temperature fatigue life of the thread of the aluminum alloy drill pipe body is implemented.

[0219] An embodiment of the present application further provides a computer program product, including a computer program, which, when executed, implements the above-mentioned method for predicting the high-temperature fatigue life of the aluminum alloy drill pipe body thread.

[0220] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0221] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "N" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0222] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing a custom logical function or process step, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed in a different order than shown or discussed, including performing functions in a substantially simultaneous manner or in a reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application pertain.

[0223] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or N wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program can be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing it in other suitable ways as necessary, and then storing it in a computer memory.

[0224] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented using hardware, as in another embodiment, it can be implemented using any one or a combination of the following technologies known in the art: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0225] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0226] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0227] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A method for predicting the high-temperature fatigue life of aluminum alloy drill pipe body threads, characterized in that: Applied to the model building stage, wherein the method comprises the following steps: A drill string dynamics model was established based on the aluminum alloy drill pipe drill string structure to obtain initial load spectrum data for the high-temperature fatigue test of the aluminum alloy drill pipe body thread. Establishing a thermal-mechanical coupling finite element model of an aluminum alloy drill pipe body thread to obtain the initial stress and strain distribution of the aluminum alloy drill pipe body thread; Performing a high temperature fatigue test on the aluminum alloy material used for the aluminum alloy drill pipe body thread to obtain fatigue life data of the aluminum alloy material used at different temperatures; Establishing a high-temperature fatigue damage model for the aluminum alloy material based on the fatigue life data and continuum damage mechanics, wherein the high-temperature fatigue damage model includes creep damage evolution and fatigue damage evolution; Based on the initial load spectrum data, the initial stress-strain distribution, fatigue life data, creep damage evolution and fatigue damage evolution in the high-temperature fatigue damage model, a high-temperature fatigue life prediction model for predicting the high-temperature fatigue life of the aluminum alloy drill pipe body thread is constructed.

2. The method according to claim 1, characterized in that The drill string dynamics model is a beam-shell combined unit model that takes temperature effects into account. The drill string dynamics model is established based on the aluminum alloy drill pipe drill string structure, including: Determine the contact state between the drill string and the well wall according to the target contact model; Dividing the area between the drill string and the wellbore wall into a first contact area and a second contact area based on the contact state, wherein the contact time between the drill string and the wellbore wall in the first contact area is much longer than the contact time between the drill string and the wellbore wall in the second contact area; constructing a shell element model in the drill string dynamics model based on the first contact area; constructing a beam element model in the drill string dynamics model based on the second contact area; Combining the shell element model and the beam element model to construct a drill string grid model; The drill string dynamics model is constructed based on the drill string grid model and the Lagrange equation.

3. The method according to claim 1, characterized in that The mesh model of the aluminum alloy drill rod body thread thermal-mechanical coupling finite element model is a three-dimensional hexahedral mesh model, and the load boundary of the aluminum alloy drill rod body thread thermal-mechanical coupling finite element model is the initial load spectrum data of a single cycle obtained from the drill string dynamics model.

4. The method according to claim 1, wherein Before performing a high temperature fatigue test on the aluminum alloy material used for the thread of the aluminum alloy drill pipe body, the method further includes: Collecting sample information of the aluminum alloy material used for high temperature fatigue testing; Based on the sample information, determining temperature information of the aluminum alloy material used for the high temperature fatigue test; Based on the sample information, geometric information of the aluminum alloy drill rod body thread and material information of the aluminum alloy material used are obtained.

5. The method according to claim 1, wherein The high-temperature fatigue damage model of the aluminum alloy material used is established based on the fatigue life data and continuous damage mechanics, wherein the high-temperature fatigue damage model includes creep damage evolution and fatigue damage evolution, including: Extracting a longitudinal vibration load curve acting on the thread of the aluminum alloy drill pipe body based on the drill string dynamics model; processing the longitudinal vibration load curve to obtain load spectrum data required for performing the high temperature fatigue test; A high-temperature fatigue test is performed on the aluminum alloy material using the load spectrum data to obtain creep evolution parameters of the creep damage evolution and fatigue evolution parameters of the fatigue damage evolution.

6. The method according to claim 1, characterized in that The expression of the drill string dynamics model is: Among them, M is the overall mass matrix, C is the overall damping matrix, K(T) is the overall stiffness matrix, F is the external force on the whole, and u is the displacement matrix. is the velocity matrix, is the acceleration matrix.

7. The method according to claim 1, characterized in that in, The expression of creep damage evolution is: Where σ(t) is the stress per cycle that changes with time, t is time, and D c is creep damage, A is the inverse term parameter of stress on creep, r is the exponential term parameter of stress on creep, (1+r) is the multiplier term parameter of stress on creep, m1 is the influence parameter of the current cycle creep cumulative damage on the next cycle creep damage increment, dD c is the creep damage increment of a single cycle under high temperature creep; The expression of fatigue damage evolution is: Among them, σ a is the stress amplitude, σ m is the mean stress, σ r is the average stress ratio, T is the temperature, D f is fatigue damage, B, C and E are weight coefficients of stress amplitude, mean stress and mean stress ratio respectively, M is the influencing parameter on stress amplitude, mean stress or mean stress ratio, N is fatigue life, β(T) is damage index, m2 is the influencing parameter of current cycle fatigue cumulative damage on next cycle fatigue damage increment, dD f It is the fatigue damage increment of a single cycle under mechanical fatigue.

8. The method according to claim 1, characterized in that The expression of the high temperature fatigue damage model is: dD=f(dD c , dD f ), Among them, dD is the damage increment of a single cycle under the combined action of high-temperature creep and mechanical fatigue. When damage does not occur, D = 0. When D accumulates to 1, failure occurs.

9. A method for predicting the high-temperature fatigue life of aluminum alloy drill pipe body threads, characterized in that: The high-temperature fatigue life prediction method for aluminum alloy drill pipe body threads according to any one of claims 1 to 8 is applied to the model application stage, wherein the method comprises the following steps: Obtaining actual temperature information of the aluminum alloy drill pipe body thread and actual drill string motion status information; The actual temperature information and the actual drill string motion state information are input into a pre-constructed high-temperature fatigue life prediction model to obtain a high-temperature fatigue life prediction result of the actual aluminum alloy drill pipe body thread, wherein the pre-constructed high-temperature fatigue life prediction model is obtained from a high-temperature fatigue damage model.

10. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for predicting the high-temperature fatigue life of an aluminum alloy drill pipe body thread according to any one of claims 1 to 8 or the method for predicting the high-temperature fatigue life of an aluminum alloy drill pipe body thread according to claim 9.

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