Strength calculation method and device for downhole tool and calculation equipment

Abstract

The invention discloses a strength calculation method and device for a downhole tool and calculation equipment, and the method comprises the steps: constructing a strength calculation model of the downhole tool, and the strength calculation model comprises a downhole tool model, a well wall model and a bending drive well wall model; setting boundary conditions of the downhole tool model, the well wall model and the bending driving well wall model, and determining time steps for loading the boundary conditions; wherein the boundary conditions include conditions for limiting contact, axial rotation, displacement, fluid pressure, tension or pressure, torque and bending; and according to the time step, loading boundary conditions on the strength calculation model to obtain a stress result. Based on the method, the combined action of pressure, tension or pressure, torque, bending and axial rotation can be realized to realize strength calculation, so that bending simulation in different directions can be completed in one-time calculation.

Description

Technical Field

[0001] The present invention relates to a strength calculation method for a downhole tool, and in particular to a strength calculation method, device, computing equipment and computer storage medium for a downhole tool. Background Art

[0002] Downhole tools are subject to fluid pressure, axial tension or pressure, torque, and forced bending from the well wall. Figure 1 As shown. At the same time, the downhole tool itself will rotate, and the downhole tool will be affected by these loads. At this time, whether the structural strength of the downhole tool meets the requirements needs to be calculated.

[0003] At present, the strength calculations of downhole tools in China are mostly carried out under single or partial working conditions, such as strength simulation under specified pressure or strength simulation under the combined action of pressure and tension. More often, reference and analogy designs are carried out, and partial working condition simulations are carried out for local structures with large differences. It is difficult to achieve a simulation that is close to the actual bending of the tool in these working conditions. Many design simulations often use the three-point bending method for approximate simulation calculations. Such simulations can obtain relatively correct results when the bending stiffness of the tool does not change much. The structural stiffness of some tools, especially logging while drilling tools, varies greatly. At this time, the three-point bending simulation method cannot obtain satisfactory results. At the same time, such a simulation method is difficult to achieve the joint action with other working condition loads. In addition Figure 2 The schematic diagram of the structural features of downhole tools in various positions under general well conditions in the prior art is shown. Figure 2 It can be seen that the downhole tool is not a complete axisymmetric figure, and the stress results of bending in one direction may be very different from those of bending in another direction. In general simulation methods, bending in different directions requires multiple calculations. Summary of the invention

[0004] In view of the above problems, the present invention is proposed to provide a strength calculation method, apparatus, computing device and computer storage medium for downhole tools that overcome the above problems or at least partially solve the above problems.

[0005] According to one aspect of the present invention, there is provided a strength calculation method for a downhole tool, comprising:

[0006] Constructing a strength calculation model of the downhole tool, wherein the strength calculation model includes: a downhole tool model, a wellbore model and a bending-driven wellbore model;

[0007] Setting boundary conditions for the downhole tool model, the wellbore model, and the bending-driven wellbore model and determining the time step for loading the boundary conditions; wherein the boundary conditions include conditions for limiting contact, axial rotation, displacement, fluid pressure, tension or pressure, torque, and bending;

[0008] According to the time step, the boundary conditions are loaded on the strength calculation model to obtain the stress results.

[0009] In an optional embodiment, the downhole tool model is a model of stiffness variation with multiple diameter reductions; the wellbore model is a cylinder with an annular cross-section, wherein the inner hole diameter of the wellbore model is the actual measured downhole diameter; and the bending-driven wellbore model is determined based on the actual wellbore curvature.

[0010] In an optional embodiment, the boundary conditions further include:

[0011] Boundary condition 1: The downhole tool model and the wellbore model are set to be in contact;

[0012] Boundary condition 2: The wellbore model and the bending-driven wellbore model are set to be in contact;

[0013] Boundary condition 3: One end of the wellbore model is set to release the Z-axis rotation;

[0014] Boundary condition 4: The other end of the well wall model is set to restrict the movement of the well wall model in the Y-axis direction;

[0015] Boundary condition 5: one end of the downhole tool model is set to limit the movement of the downhole tool model in the Z-axis direction;

[0016] Boundary condition 6: Set the fluid pressure exerted by the fluid in the well wall on the downhole tool model;

[0017] Boundary condition 7: Set the axial tension or pressure along the X-axis at the other end of the downhole tool model;

[0018] Boundary condition 8: Set the torque along the X-axis at the other end of the downhole tool model;

[0019] Boundary condition 9: setting the axial angular displacement of the other end of the downhole tool model along the X-axis; and Boundary condition 10: setting the movement value of the bending-driven well wall model along the Y-axis direction;

[0020] Among them, the X-axis is the length direction along the well wall model, the Y-axis is the bending direction of the bending-driven well wall model, and the Z-axis is perpendicular to the X-axis and the Y-axis.

[0021] In an optional embodiment, determining the time step for loading the boundary condition further includes:

[0022] According to the axial angular displacement of boundary condition 9, the total number of time steps is determined to be n, where n is greater than 1;

[0023] Determine the time step range used to load each boundary condition, as well as the loading values ​​of some boundary conditions at each time step.

[0024] In an optional implementation, the time step range for loading each boundary condition is specifically determined as follows: the time step range for loading boundary condition 1, boundary condition 2, boundary condition 3, boundary condition 4, boundary condition 5, and boundary condition 6 is determined to be 1 to n; the time step range for loading boundary condition 7, boundary condition 8, boundary condition 9, and boundary condition 10 is determined to be 2 to n;

[0025] Determining the loading values ​​of some boundary conditions at each time step further includes: determining that the loading value of boundary condition 9 at each time step increases by multiples; and determining that the loading values ​​of boundary condition 6, boundary condition 7, boundary condition 8 and boundary condition 10 at each time step are respectively maximum values.

[0026] In an optional implementation, after obtaining the stress result, the method further includes:

[0027] Check whether the contact surface between the downhole tool model and the wellbore model is interpenetrating. If so, the boundary conditions need to be reset.

[0028] Check whether the contact between the wellbore model and the bending-driven wellbore model is good. If not, the boundary conditions need to be reset.

[0029] In an optional implementation, after obtaining the stress result, the method further includes:

[0030] Check that all boundary conditions are fully enforced; and

[0031] View the stress results at each time step.

[0032] According to another aspect of the present invention, there is provided a strength calculation device for a downhole tool, the device comprising:

[0033] A construction module is used to construct a strength calculation model of a downhole tool, wherein the strength calculation model includes: a downhole tool model, a well wall model and a bending-driven well wall model;

[0034] A setting module, used to set the boundary conditions of the downhole tool model, the wellbore model and the bending-driven wellbore model and determine the time step for loading the boundary conditions; wherein the boundary conditions include conditions for limiting contact, axial rotation, displacement, fluid pressure, tension or pressure, torque and bending;

[0035] The loading module is used to load boundary conditions on the strength calculation model according to the time step and obtain stress results.

[0036] According to another aspect of the present invention, there is provided a computing device, comprising: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus;

[0037] The memory is used to store at least one executable instruction, and the executable instruction enables the processor to execute operations corresponding to the strength calculation method for downhole tools.

[0038] According to another aspect of the present invention, a computer storage medium is provided, in which at least one executable instruction is stored, and the executable instruction enables a processor to execute operations corresponding to the strength calculation method for downhole tools as described above.

[0039] According to the strength calculation method, device, computing equipment and computer storage medium for downhole tools of the present invention, a strength calculation model of downhole tools is constructed, wherein the strength calculation model includes: a downhole tool model, a well wall model and a bending-driven well wall model; boundary conditions of the downhole tool model, the well wall model and the bending-driven well wall model are set and the time step for loading the boundary conditions is determined; wherein the boundary conditions include conditions for limiting contact, axial rotation, displacement, fluid pressure, tension or pressure, torque and bending; according to the time step, the boundary conditions are loaded on the strength calculation model to obtain stress results. Based on the strength calculation method for downhole tools of this scheme, pressure, tension or pressure, torque, bending and axial rotation can be realized to realize strength calculation by joint action, so that bending simulations in different directions can be completed in one calculation.

[0040] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0042] Figure 1 A schematic diagram showing the force of a downhole tool when passing through a curved well section in the prior art is shown;

[0043] Figure 2 It is a schematic diagram of the structural features of downhole tools in various positions under general well conditions in the prior art;

[0044] Figure 3A schematic flow chart of a strength calculation method for a downhole tool provided by an embodiment of the present invention is shown;

[0045] Figure 4 A schematic diagram showing the structure of a strength calculation model provided by an embodiment of the present invention is shown;

[0046] Figure 5 A schematic diagram of calculating the radius of curvature and the maximum displacement provided by an embodiment of the present invention is shown;

[0047] Figures 6 to 9 A schematic diagram showing boundary conditions of a downhole tool model, a wellbore model and a bending-driven wellbore model provided in an embodiment of the present invention;

[0048] Fig.10 A schematic diagram of the contact interface between the well wall model and the bending-driven well wall model in an embodiment of the present invention is shown;

[0049] Fig.11 A schematic diagram of a bending-driven wellbore model provided in Example 1 of the present invention is shown;

[0050] Fig.12 A schematic diagram of a strength calculation model provided in Example 1 of the present invention is shown;

[0051] Fig.13 A schematic diagram of the contact interface between the downhole tool model and the well wall model of Example 1 of the present invention is shown;

[0052] Fig.14 A schematic diagram showing an expected bending state of a downhole tool model according to Example 1 of the present invention is shown;

[0053] Fig.15 A schematic diagram showing an actual bending state of a downhole tool model according to Example 1 of the present invention is shown;

[0054] Fig.16 A side view showing an actual bending state of the downhole tool model of Example 1 of the present invention;

[0055] Figures 17A-17D A schematic diagram of stress results of Example 2 of the present invention at some time steps is shown;

[0056] Fig.18 A functional structure diagram of a strength calculation device for a downhole tool provided by an embodiment of the present invention is shown; and

[0057] Fig.19 A schematic diagram of the structure of a computing device provided in Embodiment 3 of the present invention is shown. DETAILED DESCRIPTION

[0058] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0059] Figure 3 FIG. 1 is a flow chart of a strength calculation method for a downhole tool provided by an embodiment of the present invention; Figure 3 As shown, the method includes:

[0060] Step S110, constructing a strength calculation model of the downhole tool, wherein the strength calculation model includes: a downhole tool model, a wellbore model and a bending-driven wellbore model.

[0061] Specifically, the strength calculation method for downhole tools of this embodiment is particularly suitable for strength calculation of downhole tools under comprehensive working conditions. Figure 4 FIG. 4 shows a schematic diagram of the structure of the strength calculation model provided by an embodiment of the present invention. Figure 4 As shown, the strength calculation model includes three parts, a downhole tool model, a wellbore model and a bending-driven wellbore model, wherein the downhole tool model needs to be modeled according to the actual results. In this example, the downhole tool model is a model of stiffness variation with multiple diameter reductions; the wellbore model is a cylinder with an annular cross-section, wherein the inner hole diameter of the wellbore model is the actually measured downhole diameter; and the bending-driven wellbore model is determined based on the actual wellbore curvature.

[0062] Figure 5 FIG. 4 shows a schematic diagram of calculating the curvature radius and the maximum displacement provided by an embodiment of the present invention, as shown in FIG. Figure 5 As shown, according to the given wellbore curvature, the curvature radius and maximum displacement of the curved drive well wall can be calculated, and the curved drive well wall model can be established based on the curvature radius and maximum displacement of the curved drive well wall. When the full angle change rate is known, the bending angle θ when the downhole tool length is L can be known. According to the following formulas (1) and (2), the curvature radius R and deflection of the curved drive well wall can be further calculated.

[0063]

[0064] Step S120, setting boundary conditions of the downhole tool model, the wellbore model and the bending-driven wellbore model and determining the time step for loading the boundary conditions; wherein the boundary conditions include conditions for limiting contact, axial rotation, displacement, fluid pressure, tension or pressure, torque and bending.

[0065] Specifically, Figures 6 to 9A schematic diagram showing boundary conditions of a downhole tool model, a wellbore model and a bending-driven wellbore model provided in an embodiment of the present invention is shown. The boundary conditions further include:

[0066] Boundary condition 1: The downhole tool model and the wellbore model are set to contact (such as Figure 6 shown);

[0067] Boundary condition 2: The wellbore model and the bending-driven wellbore model are set to contact (such as Figure 6 shown);

[0068] Boundary condition 3: One end of the wellbore model is set to release the Z-axis rotation (such as Figure 7 shown);

[0069] Boundary condition 4: The other end of the well wall model is set to limit the movement of the well wall model in the Y axis (such as Figure 7 shown);

[0070] Boundary condition 5: One end of the downhole tool model is set to limit the movement of the downhole tool model in the Z-axis direction (such as Figure 8 shown);

[0071] Boundary condition 6: Set the fluid pressure exerted by the fluid in the well wall on the downhole tool model (such as Figure 8 shown);

[0072] Boundary condition 7: Set the axial tension or pressure along the X-axis at the other end of the downhole tool model (such as Figure 8 shown);

[0073] Boundary condition 8: Set the torque along the X-axis at the other end of the downhole tool model (such as Figure 8 shown);

[0074] Boundary condition 9: Set the axial angular displacement of the other end of the downhole tool model along the X-axis (such as Figure 8 shown); and

[0075] Boundary condition 10: Set the movement value of the bending-driven wellbore model along the Y-axis direction (such as Fig. 9 shown);

[0076] Among them, the X-axis is the length direction along the well wall model, the Y-axis is the bending direction of the bending-driven well wall model, and the Z-axis is perpendicular to the X-axis and the Y-axis.

[0077] Specifically, determining the time step for loading boundary conditions further includes:

[0078] According to the axial angular displacement of boundary condition 9, the total number of time steps is determined to be n, where n is greater than 1;

[0079] Determine the time step range used to load each boundary condition, as well as the loading values ​​of some boundary conditions at each time step.

[0080] In an optional embodiment, determining the time step range for loading each boundary condition is specifically as follows: determining that the time step range for loading boundary conditions 1-10 is 1 to n; determining the loading value of some boundary conditions at each time step further includes: determining that the loading value of boundary condition 9 at each time step increases by multiples; determining that the loading values ​​of boundary condition 6, boundary condition 7, boundary condition 8 and boundary condition 10 at each time step are respectively maximum values.

[0081] In another optional embodiment, the time step range for loading each boundary condition is determined as follows: the time step range for loading boundary conditions 1, boundary conditions 2, boundary conditions 3, boundary conditions 4, boundary conditions 5 and boundary conditions 6 is determined to be 1 to n; the time step range for loading boundary conditions 7, boundary conditions 8, boundary conditions 9 and boundary conditions 10 is determined to be 2 to n; the loading value of some boundary conditions at each time step further includes: determining that the loading value of boundary condition 9 at each time step increases by multiples; determining that the loading values ​​of boundary conditions 6, boundary conditions 7, boundary conditions 8 and boundary conditions 10 at each time step are respectively the maximum values. In this embodiment, each boundary condition is gradually loaded in a gradually increasing manner, so that a large stress range can be obtained in actual calculations without considering the strength limitations of structures such as downhole tools.

[0082] In an optional implementation, the bending-driven wellbore model is set to be rigid, and the downhole tool model and the wellbore model can be gridded according to actual conditions.

[0083] Step S130, loading boundary conditions on the strength calculation model according to the time step to obtain stress results.

[0084] Specifically, use the penetration tool to check whether the contact surface between the downhole tool model and the wellbore model is penetrated. If so, it is necessary to reset boundary condition 1; check whether the wellbore model and the bending drive wellbore model are in good contact. If not, it is necessary to reset boundary condition 2, such as Fig.10 As shown, set the lower limit of the solid line (the black solid line in the middle of the grid, which can be displayed as a red solid line in the actual instrument) to -0.1, check the display length of the solid line, and if there is a solid line in the middle area of ​​the entire length, it means that the contact is good. If not, you need to reset boundary condition 2 and the grid size and re-solve the calculation. After ensuring that boundary conditions 1 and 2 are set valid, check whether all boundary conditions under the comprehensive working condition are effective through dynamic display; and check the stress results under each time step and select the maximum value of the stress result at each time step.

[0085] The strength calculation method for downhole tools of this embodiment will be described below based on two specific examples.

[0086] Example 1

[0087] First, the radius R and deflection ω of the curved drive shaft wall are calculated based on the above equations (1) and (2): Fig.11 shown.

[0088] Secondly, set up the strength calculation model, such as Fig.12 shown.

[0089] Then, set boundary conditions 1-10, the specific settings are as follows:

[0090] Boundary condition 1: The downhole tool model and the wellbore model are set to be in contact;

[0091] Boundary condition 2: The wellbore model and the bending-driven wellbore model are set to be in contact;

[0092] Boundary condition 3: One end of the wellbore model is set to release the Z-axis rotation;

[0093] Boundary condition 4: The other end of the well wall model is set to restrict the movement of the well wall model in the Y-axis direction;

[0094] Boundary condition 5: One end of the downhole tool model is set to restrict the movement of the downhole tool model in the Z-axis direction;

[0095] Boundary condition 6: The fluid pressure exerted by the fluid in the well wall on the downhole tool model is 100 MPa;

[0096] Boundary condition 7: The axial tension or pressure along the X-axis at the other end of the downhole tool model is -1000N;

[0097] Boundary condition 8--Set the torque along the X-axis at the other end of the downhole tool model to 10000 N·mm;

[0098] Boundary condition 9--Set the axial angular displacement of the other end of the downhole tool model along the X-axis to 60°;

[0099] Boundary condition 10: Set the movement value of the bending-driven well wall model along the Y-axis to 19.5 mm.

[0100] Among them, the X-axis is the length direction along the well wall model, the Y-axis is the bending direction of the bending-driven well wall model, and the Z-axis is perpendicular to the X-axis and the Y-axis.

[0101] In this example, the specific values ​​of the boundary conditions are set for a clearer description of the technical solution and are not specifically limited. Those skilled in the art may set them according to actual needs.

[0102] The boundary condition time step is determined based on the set boundary conditions. Specifically, see Table 1-Table 4.

[0103] Table 1

[0104] Time(s) X(mm) Y(mm) RX(°) 0 0 0 0 1 0 0 0 2 0 0 30 3 0 0 60

[0105] Table 2

[0106] Time(s) Force (N) 0 -1000 1 -1000 2 -1000 3 -1000

[0107] Table 3

[0108]

[0109]

[0110] Table 4

[0111] Time(s) Pressure(MPa) 0 100 1 100 2 100 3 100

[0112] In this example, the axial angular displacement of the other end of the downhole tool model along the X-axis is 60°, as shown in Table 5. In this example, the number of segmentation steps is 3, the total number of time steps is 3, the first time step ends at 1s, the second time step ends at 2s, and the third time step ends at 3s; Tables 2-4 show the axial tension or pressure, the torque of the downhole tool model along the X-axis, and the fluid pressure of Example 1 of the present invention at each time step. Determine that the time step range for loading boundary conditions 1-10 is 1 to 3; determine that the loading value of some boundary conditions at each time step further includes: determine that the loading value of boundary condition 9 at each time step increases by multiples; determine that the loading values ​​of boundary conditions 6, boundary conditions 7, boundary conditions 8 and boundary conditions 10 at each time step are respectively the maximum values.

[0113] Table 5

[0114]

[0115] After setting the boundary conditions and determining the boundary condition time step, check the contact gap between boundary condition 2, i.e. the wellbore model and the bending drive wellbore model, to ensure good contact over the entire length. Use the penetration tool to check the penetration value of boundary condition 1. Fig.13 It can be seen that there is almost no penetration along the entire length, and the penetration value meets the requirements. The dynamic display can be used to check whether all boundary conditions under the comprehensive working conditions are effective. Fig.14 A schematic diagram showing an expected bending state of a downhole tool model according to Example 1 of the present invention is shown; Fig.15 A schematic diagram showing an actual bending state of a downhole tool model according to Example 1 of the present invention is shown; Fig.16 FIG. 1 shows a side view of the actual bending state of the downhole tool model of Example 1 of the present invention. Figure 14-16It can be seen that after all boundary conditions have taken effect, the stress results at different time steps are checked.

[0116] Example 2

[0117] First, the radius R and deflection ω of the bending-driven wellbore are calculated based on the above formulas (1) and (2). Secondly, the strength calculation model is set, and then the boundary conditions 1-10 are set. For details, please refer to Example 1, which will not be repeated here. The boundary condition time step is determined based on the set boundary conditions. In this example, the axial angular displacement of the other end of the downhole tool model along the X-axis is 60°, the number of segmentation steps is 8, and the total number of time steps is 8, among which the first time step ends at 1 second, the second time step ends at 1.25 seconds, the third time step ends at 1.5 seconds, the fourth time step ends at 1.75 seconds, the fifth time step ends at 1.85 seconds, the sixth time step ends at 1.925 seconds, the seventh time step ends at 2 seconds, and the eighth time step ends at 3 seconds. Determining the time step range for loading each boundary condition is specifically as follows: determining the time step range for loading boundary condition 1, boundary condition 2, boundary condition 3, boundary condition 4, boundary condition 5 and boundary condition 6 to be 1 to 8; determining the time step range for loading boundary condition 7, boundary condition 8, boundary condition 9 and boundary condition 10 to be 2 to 8; determining the loading value of some boundary conditions at each time step further includes: determining that the loading value of boundary condition 9 at each time step increases by multiples; determining that the loading values ​​of boundary condition 6, boundary condition 7, boundary condition 8 and boundary condition 10 at each time step are respectively maximum values. Figures 17A-17D A schematic diagram of stress results of Example 2 of the present invention at a partial time step is shown.

[0118] According to the strength calculation method for downhole tools of this embodiment, the combined action of pressure, tension or stress, torque, bending and axial rotation can be realized to realize strength calculation, so that bending simulation in different directions can be completed in one calculation.

[0119] Fig.18 FIG. 2 shows a functional structure diagram of a strength calculation device 200 for a downhole tool provided by an embodiment of the present invention. Fig.18 As shown, the strength calculation device 200 includes: a construction module 210 , a setting module 220 and a loading module 230 .

[0120] A construction module 210 is used to construct a strength calculation model of the downhole tool, wherein the strength calculation model includes: a downhole tool model, a wellbore model and a bending-driven wellbore model;

[0121] A setting module 220 is used to set boundary conditions of the downhole tool model, the wellbore model and the bending-driven wellbore model and determine a time step for loading the boundary conditions; wherein the boundary conditions include conditions for defining contact, axial rotation, displacement, fluid pressure, tension or pressure, torque and bending;

[0122] The loading module 230 is used to load boundary conditions on the strength calculation model according to the time step to obtain stress results.

[0123] In an optional embodiment, the downhole tool model is a model of stiffness variation with multiple diameter reductions; the wellbore model is a cylinder with an annular cross-section, wherein the inner hole diameter of the wellbore model is the actual measured downhole diameter; and the bending-driven wellbore model is determined based on the actual wellbore curvature.

[0124] In an optional embodiment, the boundary conditions further include:

[0125] Boundary condition 1: the downhole tool model and the well wall model are set to be in contact;

[0126] Boundary condition 2: the wellbore model and the bending driven wellbore model are set to be in contact;

[0127] Boundary condition 3: One end of the wellbore model is set to release the Z-axis rotation;

[0128] Boundary condition 4: The other end of the well wall model is set to restrict the movement of the well wall model in the Y-axis direction;

[0129] Boundary condition 5: one end of the downhole tool model is set to limit the movement of the downhole tool model in the Z-axis direction;

[0130] Boundary condition 6: Set the fluid pressure exerted by the fluid in the well wall on the downhole tool model;

[0131] Boundary condition 7: Set the axial tension or pressure along the X-axis at the other end of the downhole tool model;

[0132] Boundary condition 8: Set the torque along the X-axis at the other end of the downhole tool model;

[0133] Boundary condition 9: setting the axial angular displacement of the other end of the downhole tool model along the X-axis; and Boundary condition 10: setting the movement value of the bending-driven well wall model along the Y-axis direction;

[0134] Among them, the X-axis is the length direction along the well wall model, the Y-axis is the bending direction of the bending-driven well wall model, and the Z-axis is perpendicular to the X-axis and the Y-axis.

[0135] In an optional embodiment, the loading module 230 is further adapted to:

[0136] According to the axial angular displacement of boundary condition 9, the total number of time steps is determined to be n, where n is greater than 1;

[0137] Determine the time step range used to load each boundary condition, as well as the loading values ​​of some boundary conditions at each time step.

[0138] In an optional implementation, the time step range for loading each boundary condition is specifically determined as follows: the time step range for loading boundary condition 1, boundary condition 2, boundary condition 3, boundary condition 4, boundary condition 5, and boundary condition 6 is determined to be 1 to n; the time step range for loading boundary condition 7, boundary condition 8, boundary condition 9, and boundary condition 10 is determined to be 2 to n;

[0139] Determining the loading values ​​of some boundary conditions at each time step further includes: determining that the loading value of boundary condition 9 at each time step increases by multiples; and determining that the loading values ​​of boundary condition 6, boundary condition 7, boundary condition 8 and boundary condition 10 at each time step are respectively maximum values.

[0140] In an optional embodiment, the device 200 further includes a first inspection module, and the first inspection module is adapted to:

[0141] After obtaining the stress results, check whether the contact surface between the downhole tool model and the wellbore model is penetrated. If so, the boundary conditions need to be reset;

[0142] Check whether the contact between the wellbore model and the bending-driven wellbore model is good. If not, the boundary conditions need to be reset.

[0143] In an optional embodiment, the device 200 further includes a second inspection module, and the second inspection module is adapted to:

[0144] After obtaining stress results, check that all boundary conditions are fully effective; and

[0145] View the stress results at each time step.

[0146] It can be seen that according to the strength calculation device for downhole tools of this embodiment, it is possible to realize the combined action of pressure, tension or pressure, torque, bending and axial rotation to realize strength calculation, so that bending simulation in different directions can be completed in one calculation.

[0147] According to an embodiment of the present invention, a non-volatile computer storage medium is provided. The computer storage medium stores at least one executable instruction. The computer executable instruction can execute the method in any of the above method embodiments.

[0148] Fig.19 A schematic diagram of the structure of a computing device provided by an embodiment of the present invention is shown. The specific embodiment of the present invention does not limit the specific implementation of the computing device.

[0149] like Fig.19 As shown, the computing device may include: a processor (processor) 302 , a communication interface (Communications Interface) 304 , a memory (memory) 306 , and a communication bus 308 .

[0150] The processor 302, the communication interface 304, and the memory 306 communicate with each other via the communication bus 308. The communication interface 304 is used to communicate with other devices such as a client or other server network elements. The processor 302 is used to execute the program 310, which can specifically execute the relevant steps in the above method embodiment.

[0151] Specifically, the program 310 may include program codes, which include computer operation instructions.

[0152] The processor 302 may be a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present invention. The one or more processors included in the computing device may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0153] The memory 306 is used to store the program 310. The memory 306 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.

[0154] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0155] Similarly, it should be understood that in order to streamline the present invention and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, the various features of the embodiments of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the following intention: that the claimed invention requires more features than the features explicitly recited in each claim. More specifically, as reflected in the claims below, inventive aspects lie in less than all the features of the individual embodiments disclosed above. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, with each claim itself serving as a separate embodiment of the present invention.

[0156] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and in addition they may be divided into a plurality of submodules or subunits or subcomponents. Except that at least some of such features and / or processes or units are mutually exclusive, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this manner may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0157] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the claims below, any one of the claimed embodiments may be used in any combination.

[0158] It should be noted that the above embodiments illustrate the present invention rather than limit it, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by means of hardware comprising a number of different elements and by means of a suitably programmed computer. In a unit claim enumerating a number of devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be understood as limitations on the order of execution.

Claims

1. A strength calculation method for downhole tools, characterized in that: include: Constructing a strength calculation model of the downhole tool, wherein the strength calculation model includes: a downhole tool model, a wellbore model and a bending-driven wellbore model; Setting boundary conditions of the downhole tool model, the wellbore model and the bending-driven wellbore model and determining a time step for loading the boundary conditions; wherein the boundary conditions include conditions for limiting contact, axial rotation, displacement, fluid pressure, tension or pressure, torque and bending; According to the time step, the boundary conditions are loaded on the strength calculation model to obtain stress results.

2. The strength calculation method according to claim 1, wherein: The downhole tool model is a model of stiffness variation with multiple diameter reductions; the wellbore model is a cylinder with an annular cross-section, wherein the inner hole diameter of the wellbore model is the actually measured downhole diameter; and the bending-driven wellbore model is determined based on the actual wellbore curvature.

3. The strength calculation method according to claim 1, characterized in that: The boundary conditions further include: Boundary condition 1: the downhole tool model and the well wall model are set to be in contact; Boundary condition 2: the wellbore model and the bending-driven wellbore model are set to be in contact; Boundary condition 3: one end of the well wall model is set to release the Z-axis rotation; Boundary condition 4: the other end of the well wall model is set to limit the movement of the well wall model in the Y-axis direction; Boundary condition 5: one end of the downhole tool model is set to limit the movement of the downhole tool model in the Z-axis direction; Boundary condition 6: setting the fluid pressure exerted by the fluid in the well wall on the downhole tool model; Boundary condition 7: setting the axial tension or pressure along the X-axis at the other end of the downhole tool model; Boundary condition 8: setting the torque along the X-axis at the other end of the downhole tool model; Boundary condition 9: setting the axial angular displacement of the other end of the downhole tool model along the X-axis; and Boundary condition 10: setting the movement value of the bending driven well wall model along the Y-axis direction; The X-axis is the length direction along the well wall model, the Y-axis is the bending direction of the bending-driven well wall model, and the Z-axis is perpendicular to the X-axis and the Y-axis.

4. The strength calculation method according to claim 3, characterized in that: The determining of the time step for loading the boundary condition further comprises: According to the axial angular displacement of the boundary condition 9, the total number of time steps is determined to be n, where n is greater than 1; Determine the time step range used to load each boundary condition, as well as the loading values ​​of some boundary conditions at each time step.

5. The strength calculation method according to claim 4, characterized in that: The time step range for loading each boundary condition is specifically determined as follows: the time step range for loading boundary condition 1, boundary condition 2, boundary condition 3, boundary condition 4, boundary condition 5 and boundary condition 6 is determined to be 1 to n; the time step range for loading boundary condition 7, boundary condition 8, boundary condition 9 and boundary condition 10 is determined to be 2 to n; Determining the loading value of the partial boundary condition at each time step further includes: determining that the loading value of the boundary condition 9 at each time step increases by multiples; Determine that the loading values ​​of boundary conditions 6, boundary conditions 7, boundary conditions 8 and boundary conditions 10 at each time step are respectively the maximum values.

6. The strength calculation method according to claim 3, characterized in that: After obtaining the stress result, the method further includes: Check whether the contact surface between the downhole tool model and the well wall model penetrates, and if so, reset the boundary condition; Check whether the well wall model and the bending driven well wall model are in good contact. If not, reset the boundary condition.

7. The strength calculation method according to claim 1, characterized in that: After obtaining the stress result, the method further includes: Check that all boundary conditions are fully enforced; and View the stress results at each time step.

8. A strength calculation device for downhole tools, characterized in that: include: A construction module, used to construct a strength calculation model of the downhole tool, wherein the strength calculation model includes: a downhole tool model, a well wall model and a bending-driven well wall model; A setting module, used to set the boundary conditions of the downhole tool model, the wellbore model and the bending-driven wellbore model and determine the time step for loading the boundary conditions; wherein the boundary conditions include conditions for limiting contact, axial rotation, displacement, fluid pressure, tension or pressure, torque and bending; A loading module is used to load the boundary conditions on the strength calculation model according to the time step to obtain stress results.

9. A computing device comprising: A processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the strength calculation method for downhole tools as described in any one of claims 1-7.

10. A computer storage medium, wherein at least one executable instruction is stored in the storage medium, wherein the executable instruction enables a processor to execute operations corresponding to the strength calculation method for a downhole tool as described in any one of claims 1 to 7.

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