Method and system for evaluating bearing capacity of derrick of petroleum drilling machine

Abstract

The invention discloses a method and system for evaluating the bearing capacity of a derrick of a petroleum drilling machine, and the method comprises the following steps: applying load information for simulating the external force borne by the derrick in a working environment to a to-be-evaluated derrick, obtaining a first stress of the derrick, and calculating the bearing capacity of the derrick according to the first stress; obtaining a second stress representing the maximum static load borne by the to-be-evaluated derrick; utilizing the physical property parameters of the rod piece on the derrick to be evaluated to generate the maximum axial tension and compression stress allowed under the condition that the derrick only has the axial tension and compression stress; and the actual bearing capacity of the derrick to be evaluated is judged by comparing the second stress with the maximum axial tension and compression stress. According to the method, direct calculation of the bearing capacity of the derrick of the petroleum drilling machine is realized, the health condition of the derrick is reflected in time, and technical support is provided for taking measures such as maintenance and adjustment for performance degradation of the derrick to avoid emergencies.

Description

Technical Field

[0001] The present invention belongs to the technical field of derrick condition detection, and in particular relates to a method and system for evaluating the bearing capacity of an oil drilling rig derrick. Background Art

[0002] Most oil derrick structures are located in remote wild areas, exposed to wind and rain erosion all year round, with a harsh working environment, and large loads during operation, making them difficult to maintain. In addition, when the well site is transferred, it is inevitable to disassemble, transport the oil derrick structure. Further combined with the problems of degradation, fatigue, corrosion, etc. that are prone to occur in the material properties of the oil derrick structure, it has led to damages such as cracks and deformations in the steel structure of the oil derrick, thereby reducing the bearing capacity of the oil derrick structure and shortening the service life of the steel structure of the oil derrick. The degradation of the performance of the oil derrick structure will not only affect the process of oil and gas field development, but may even cause the sudden collapse of the steel structure of the oil derrick, resulting in major economic losses and casualties.

[0003] In the process of implementing the present invention, the inventor found that the decline in the bearing capacity of the oil drilling rig derrick is mainly divided into the following three situations:

[0004] (1) Excessive local stress. When the derrick undergoes local deformation or sudden overload, etc., it will cause excessive local stress in the derrick. When the stress value exceeds the stress threshold of the derrick member, fatigue fracture of the derrick member may occur, which may cause the entire derrick to malfunction and even lead to personal injury accidents.

[0005] (2) Derrick inclination. After long-term service of the metal derrick, affected by the lateral wind load and the unevenness of the derrick foundation settlement process, the overall inclination of the derrick will occur. The inclination of the metal derrick during use directly leads to the deviation of the lifting center line. At this time, the overall force of the derrick is uneven, making the inclination degree of the derrick more serious, which has a very serious impact on the production safety of oil extraction.

[0006] (3) Fault vibration. When the hoisting system of the metal derrick hoists heavy objects, it is subjected to violent impacts or frequent starts and stops, which will form exciting forces. If the exciting force is too large or the exciting frequency is close to the natural frequency of the derrick, it will not only affect the normal operation of the hoist, but may also resonate with the metal derrick, increasing the amplitude of the derrick structure and causing the derrick vibration to intensify. At the same time, the fault vibration will also affect the normal operation of the equipment, threaten the structural safety of the equipment, and reduce the bearing capacity of the equipment. In addition, the fault vibration will also generate extremely loud noises, causing noise pollution.

[0007] At present, there is no convenient operation evaluation system for the derrick bearing capacity. There is an urgent need for a technical means to directly calculate the derrick bearing capacity through specification parameters to timely reflect the health status of the oil drilling rig derrick, so as to timely take measures such as maintenance and adjustment for the degradation of the derrick performance, thereby effectively avoiding emergencies. Summary of the Invention

[0008] To solve the above problems, an embodiment of the present invention provides a method for evaluating the bearing capacity of an oil drilling rig derrick, including: applying load information for simulating the external forces borne by the derrick in its working environment to the derrick to be evaluated, obtaining the first stress of the derrick, and obtaining a second stress representing the maximum static load that the derrick to be evaluated can withstand according to the first stress; using the physical property parameters of the members on the derrick to be evaluated to generate the maximum allowable axial tensile and compressive stress under the condition that only axial tensile and compressive stresses exist in the derrick; determining the actual bearing capacity of the derrick to be evaluated by comparing the second stress with the maximum axial tensile and compressive stress.

[0009] Preferably, the first stress includes a first axial tensile and compressive stress, a first transverse bending stress, and a first longitudinal bending stress. Among them, in the step of obtaining the second stress representing the maximum static load that the derrick to be evaluated can withstand according to the first stress, it includes: based on the first stress, using the linear extrapolation principle to respectively predict the change trends of the first axial tensile and compressive stress, the first transverse bending stress, and the first longitudinal bending stress with the change of the load intensity, and extracting the axial tensile and compressive stress, transverse bending stress, and longitudinal bending stress corresponding to the maximum static load from the stress change trend information, so as to obtain the second stress.

[0010] Preferably, in the step of using the physical property parameters of the members on the derrick to be evaluated to generate the maximum allowable axial tensile and compressive stress under the condition that only axial tensile and compressive stresses exist in the derrick, it includes: using the physical property parameters and combining the member connection state parameters to respectively obtain the actual slenderness ratio of the member and the slenderness ratio critical value for distinguishing the elastic buckling state and the inelastic buckling state of the member; analyzing and comparing the actual slenderness ratio with the slenderness ratio critical value to obtain the maximum axial tensile and compressive stress.

[0011] Preferably, in the process of obtaining the actual slenderness ratio, it includes: respectively calculating the transverse slenderness ratio and the longitudinal slenderness ratio of the member, and when the transverse slenderness ratio is greater than the longitudinal slenderness ratio, taking the transverse slenderness ratio as the actual slenderness ratio, otherwise, taking the longitudinal slenderness ratio as the actual slenderness ratio.

[0012] Preferably, the following expressions are used to calculate the transverse slenderness ratio and the longitudinal slenderness ratio respectively:

[0013]

[0014]

[0015] Among them, λ x represents the slenderness ratio in the transverse direction, r x represents the radius of gyration in the transverse direction, k represents the effective length coefficient of the member in the plane of bending, l represents the length of the member, and λ y represents the slenderness ratio in the longitudinal direction, r y represents the radius of gyration in the longitudinal direction.

[0016] Preferably, the critical value of the slenderness ratio is obtained by using the following expression:

[0017]

[0018] Among them, C c represents the critical value of the slenderness ratio, E represents the modulus of elasticity, and F y represents the minimum yield stress.

[0019] Preferably, in the process of analyzing and comparing the actual slenderness ratio with the critical value of the slenderness ratio to obtain the maximum axial tensile and compressive stress, it includes: according to the magnitude relationship between the actual slenderness ratio and the critical value of the slenderness ratio, selecting the corresponding calculation method of the maximum axial tensile and compressive stress to calculate the maximum axial tensile and compressive stress. Among them, if the actual slenderness ratio is greater than the critical value of the slenderness ratio, the following expression is used to calculate the maximum axial tensile and compressive stress:

[0020]

[0021] Among them, F a1 represents the maximum axial tensile and compressive stress when the actual slenderness ratio is greater than the critical value of the slenderness ratio, E represents the modulus of elasticity, and λ represents the actual slenderness ratio; or if the actual slenderness ratio is less than or equal to the critical value of the slenderness ratio, the following expression is used to calculate the maximum axial tensile and compressive stress:

[0022]

[0023] Among them, F a2 represents the maximum axial tensile and compressive stress when the actual slenderness ratio is less than or equal to the critical value of the slenderness ratio, C c represents the critical value of the slenderness ratio, and F y represents the minimum yield stress.

[0024] Preferably, in the step of determining the actual bearing capacity of the derrick to be evaluated by comparing the second stress with the maximum axial tensile and compressive stress, it includes: calculating the ratio of the tensile and compressive stress in the second stress to the maximum axial tensile and compressive stress, determining the magnitude relationship between the ratio and the preset bearing capacity determination threshold, and selecting the corresponding calculation method to calculate the bearing capacity strength coefficient for characterizing whether the derrick to be evaluated currently has the ability to bear the maximum static load, so as to calculate the actual bearing capacity of the derrick to be evaluated according to the bearing capacity strength coefficient. Wherein, if the ratio is less than or equal to the preset bearing capacity determination threshold, the first bearing capacity strength coefficient is calculated using the following expression as the current bearing capacity strength coefficient:

[0025]

[0026] Wherein, U c represents the first bearing capacity strength coefficient, f a represents the tensile and compressive stress, F a represents the maximum axial tensile and compressive stress when the actual slenderness ratio is greater than the slenderness ratio critical value or the maximum axial tensile and compressive stress when the actual slenderness ratio is less than or equal to the slenderness ratio critical value, F bx and F by respectively represent the allowable bending stresses in the transverse direction and the longitudinal direction of the member under the condition of only bending moment, f bx and f by respectively represent the transverse bending stress and the longitudinal bending stress; or if the ratio is greater than the preset bearing capacity determination threshold, the second bearing capacity strength coefficient and the third bearing capacity strength coefficient are calculated respectively using the following expressions as the current bearing capacity strength coefficient:

[0027]

[0028]

[0029] Wherein, U c1 and U c2 respectively represent the second bearing capacity strength coefficient and the third bearing capacity strength coefficient, C mx and C my respectively represent the stress fitting coefficients in the transverse direction and the longitudinal direction of the member, F’ ex and F’ ey respectively represent the Euler stresses in the transverse direction and the longitudinal direction of the member divided by the safety factor.

[0030] Preferably, in the process of calculating the actual bearing capacity of the derrick to be evaluated according to the bearing capacity strength coefficient, the following steps are included: when the first bearing capacity strength coefficient is less than or equal to 1, or both the second bearing capacity strength coefficient and the third bearing capacity strength coefficient are less than or equal to 1, it is determined that the current derrick has the ability to bear the maximum static load, and a first bearing capacity parameter is generated to quantitatively characterize the actual bearing capacity of the derrick when it has the ability to bear the maximum static load; when the first bearing capacity strength coefficient is greater than 1, or any one of the second bearing capacity strength coefficient and the third bearing capacity strength coefficient is greater than 1, it is determined that the current derrick does not have the ability to bear the maximum static load, and a second bearing capacity parameter is generated to quantitatively characterize the actual bearing capacity when the derrick does not have the ability to bear the maximum static load.

[0031] Preferably, in the process of generating the first bearing capacity parameter, the following steps are included: directly taking the maximum static load as the first bearing capacity parameter; and in the process of generating the second bearing capacity parameter, the following steps are included: when the ratio is less than or equal to the preset bearing capacity determination threshold, the derrick hook load value is obtained by assigning the corresponding bearing capacity strength coefficient as 1, and the current derrick hook load value is taken as the second bearing capacity parameter; when the ratio is greater than the preset bearing capacity determination threshold, and the second bearing capacity strength coefficient is less than or equal to / greater than 1, and the third bearing capacity strength coefficient is greater than / less than or equal to 1, the derrick hook load value is obtained by assigning the third bearing capacity strength coefficient / second bearing capacity strength coefficient as 1, and the current hook load value is taken as the second bearing capacity parameter; when the ratio is greater than the preset bearing capacity determination threshold, and both the second bearing capacity strength coefficient and the third bearing capacity strength coefficient are greater than 1, the corresponding derrick hook load values are respectively obtained by assigning both the current second bearing capacity strength coefficient and the third bearing capacity strength coefficient as 1, and the smaller derrick hook load value is taken as the second bearing capacity parameter.

[0032] In addition, the present invention also proposes a bearing capacity evaluation system for an oil drilling rig derrick. The bearing capacity evaluation system includes the following modules: a stress acquisition module, which is used to apply load information for simulating the external forces borne by the derrick to be evaluated in its working environment, obtain the first stress of the derrick, and obtain the second stress representing the maximum static load that the derrick to be evaluated can bear according to the first stress; a maximum axial tensile and compressive stress calculation module, which is used to generate the maximum allowable axial tensile and compressive stress under the condition that only axial tensile and compressive stresses exist in the derrick by using the physical property parameters of the members on the derrick to be evaluated; a bearing capacity evaluation module, which is used to determine the actual bearing capacity of the derrick to be evaluated by comparing the second stress with the maximum axial tensile and compressive stress.

[0033] Compared with the prior art, one or more embodiments of the above solution may have the following advantages or beneficial effects:

[0034] The present invention provides a method and system for evaluating the bearing capacity of a derrick of an oil drilling rig. The method first applies load information for simulating the external forces borne by the derrick to be evaluated in its working environment, and then calculates the bearing capacity of the derrick to be evaluated for the maximum static load based on the strength theory and the principle of linear extrapolation, thereby obtaining the actual bearing capacity of the derrick to be evaluated. The present invention realizes the direct calculation of the bearing capacity of the derrick of the oil drilling rig, timely reflects the health status of the derrick, provides technical support for taking maintenance and adjustment measures to avoid sudden situations in response to the performance degradation of the derrick, and consumes less time and human resources.

[0035] Other features and advantages of the present invention will be described in the following specification, and some of them will become obvious from the specification, or can be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in the specification, claims, and drawings. Description of the Drawings

[0036] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0037] Figure 1 is a flowchart of the method for evaluating the bearing capacity of a derrick of an oil drilling rig according to an embodiment of the present application.

[0038] Figure 2 is a schematic diagram of the derrick structure of the method for evaluating the bearing capacity of a derrick of an oil drilling rig according to an embodiment of the present application.

[0039] Figure 3 is a schematic diagram of the strain gauge distribution of the members of the method for evaluating the bearing capacity of a derrick of an oil drilling rig according to an embodiment of the present application.

[0040] Figure 4 is a schematic diagram of the cross-sectional parameters of the members of the method for evaluating the bearing capacity of a derrick of an oil drilling rig according to an embodiment of the present application.

[0041] Figure 5 is a block diagram of the modules of the system for evaluating the bearing capacity of a derrick of an oil drilling rig according to an embodiment of the present application. Detailed Embodiments

[0042] The embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings and examples, so as to fully understand how the present invention uses technical means to solve technical problems and achieve the implementation process of technical effects and implement accordingly. It should be noted that as long as there is no conflict, the various embodiments in the present invention and the various features in each embodiment can be combined with each other, and the formed technical solutions are all within the protection scope of the present invention.

[0043] In addition, the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0044] At present, a convenient operation derrick bearing capacity evaluation system has not been formed. There is an urgent need for a technical means that can directly calculate the derrick bearing capacity through specification parameters to timely reflect the health status of the oil drilling rig derrick, so as to timely take measures such as maintenance and adjustment for the degradation of the derrick performance, thereby effectively avoiding emergencies.

[0045] Therefore, to solve the above problems, the present invention proposes a bearing capacity evaluation method and system for an oil drilling rig derrick. The method first applies load information for simulating the external forces borne by the derrick to be evaluated in its working environment, and then calculates the bearing capacity of the derrick to be evaluated for the maximum static load based on the strength theory and the principle of linear extrapolation, and further obtains the actual bearing capacity of the derrick to be evaluated. The present invention realizes the direct calculation of the bearing capacity of the oil drilling rig derrick, timely reflects the health status of the derrick, provides technical support for taking measures such as maintenance and adjustment for the degradation of the derrick performance to avoid emergencies, and consumes less time and human resources.

[0046] Example 1

[0047] Figure 1 It is a step diagram of the bearing capacity evaluation method for an oil drilling rig derrick in an embodiment of the present application. The following will refer to Figure 1 to illustrate each step of this method.

[0048] As Figure 1As shown, in step S110, load information for simulating the external forces borne by the derrick to be evaluated in its working environment is applied to the derrick to be evaluated, and the first stress of the derrick is obtained. Based on the first stress, the second stress representing the maximum static load that the derrick to be evaluated can bear is obtained. In practical applications, the external forces received by the derrick in different working environments are different. Therefore, in this embodiment, first, for the working environment of the derrick to be evaluated, load information matching the working environment is configured for the derrick to be evaluated. Then, the configured load information is loaded onto the derrick to be evaluated, enabling the derrick to be evaluated to bear simulated external forces identical to the changing external forces it bears in the corresponding working environment, thereby realizing the simulation of the external forces borne by the derrick to be evaluated in the corresponding working environment. Among them, the load information is loads with different strength levels that match the changing external forces borne by the derrick to be evaluated. After applying the load information to the derrick to be evaluated, the stress state corresponding to the derrick under the current load information is analyzed and obtained, denoted as the first stress. Next, based on the first stress, the stress state when the derrick to be evaluated bears the maximum static load is deduced, so as to represent the maximum static load that the derrick to be evaluated can bear with the second stress.

[0049] In the step of obtaining the second stress representing the maximum static load that the derrick to be evaluated can bear based on the first stress, based on the first stress, using the principle of linear extrapolation, the changing trends of the first tensile and compressive stress, the first transverse bending stress, and the first longitudinal bending stress with the change of load strength are respectively predicted, and the tensile and compressive stress, transverse bending stress, and longitudinal bending stress corresponding to the maximum static load are extracted from the information of the changing trends of each stress, thereby obtaining the second stress. Specifically, the first stress is a set of multiple types of stresses, including the first tensile and compressive stress, the first transverse bending stress, and the first longitudinal bending stress. Based on the linear relationship between the load applied to the derrick to be evaluated and the corresponding type of stress of the derrick, according to the load change characteristics in the configured load information, the change characteristics of the corresponding tensile and compressive stress, transverse bending stress, and longitudinal bending stress are obtained. Then, based on the obtained stress change characteristics, using the principle of linear extrapolation, the changing trends of the first tensile and compressive stress, the first transverse bending stress, and the first longitudinal bending stress with the change of load strength are respectively predicted. In practical applications, the maximum static load (the maximum hook load designed for the derrick) is the critical load that causes damage to the derrick. Therefore, in this embodiment, after obtaining the information on the changing trends of each stress with the change of load strength, the tensile and compressive stress, transverse bending stress, and longitudinal bending stress corresponding to the maximum static load are extracted from the change trend information as the set of maximum stresses of the derrick to be evaluated, denoted as the second stress.

[0050] Furthermore, in step S120, using the physical property parameters of the members on the derrick to be evaluated, the maximum allowable axial tensile and compressive stress under the condition that only axial tensile and compressive stresses exist in the derrick is generated. Figure 2It is a schematic diagram of the derrick structure of the bearing capacity evaluation method for the oil drilling rig derrick according to the embodiment of the present application. Refer to Figure 2 , in practical applications, the derrick is composed of members. Therefore, when applying loads, the bearing capacity of the derrick is determined by the stress state of the members. Therefore, in this embodiment, the axial tensile and compressive stresses in the stress state of the members are taken as the main factors affecting the bearing capacity of the derrick to be evaluated, and the physical property parameters of the members on the derrick to be evaluated are used to analyze the stress state of the members when the derrick bears the load. Then, according to the analysis results, the maximum axial tensile and compressive stresses allowed for the members under the condition that only axial tensile and compressive stresses exist in the derrick are generated, and the maximum axial tensile and compressive stresses of the members are used as the basis for judging the bearing capacity of the derrick to be evaluated. Accordingly, the present invention only needs to collect the stress information of the members constituting the derrick to be evaluated to obtain the bearing capacity of the derrick to be evaluated, which has strong versatility and simple operation.

[0051] In the step of generating the maximum axial tensile and compressive stresses allowed under the condition that only axial tensile and compressive stresses exist in the derrick by using the physical property parameters of the members on the derrick to be evaluated, first, the actual slenderness ratio of the members and the slenderness ratio critical value for distinguishing the elastic buckling state and the inelastic buckling state of the members are respectively obtained by using the physical property parameters in combination with the member connection state parameters; then, the actual slenderness ratio is analyzed and compared with the slenderness ratio critical value to obtain the maximum axial tensile and compressive stresses. The bearing capacity calculation of the derrick needs to consider the influence of the additional eccentricity caused by the elastoplastic deformation of the members under the action of external loads, and this influence can be reflected by the slenderness ratio. Accordingly, in this embodiment, the actual slenderness ratio of the members is calculated by using the parameters such as the member length, cross-sectional shape, and cross-sectional size in the physical property parameters in combination with the radius of gyration in the member connection state parameters. In this embodiment, the slenderness ratio critical value for distinguishing the elastic buckling state and the inelastic buckling state of the members is calculated by using the elastic modulus and the minimum yield stress in the physical property parameters. In practical applications, if the actual slenderness ratio is greater than the slenderness ratio critical value, it means that a plastic zone will appear when the member buckles; if the actual slenderness ratio is less than the slenderness ratio critical value, it means that no plastic zone will appear when the member buckles. Therefore, in this embodiment, by analyzing and comparing the actual slenderness ratio with the slenderness ratio critical value, the maximum axial tensile and compressive stresses of the members can be obtained, and the maximum axial tensile and compressive stresses obtained in this way conform to the actual working conditions, and the actual bearing capacity of the derrick to be evaluated that conforms to the actual working conditions can be obtained.

[0052] In the process of obtaining the actual slenderness ratio, the transverse slenderness ratio and the longitudinal slenderness ratio of the member are calculated respectively. When the transverse slenderness ratio is greater than the longitudinal slenderness ratio, the transverse slenderness ratio is taken as the actual slenderness ratio; otherwise, the longitudinal slenderness ratio is taken as the actual slenderness ratio. The slenderness ratio is an index used to evaluate the stiffness performance of members. In this embodiment, the transverse slenderness ratio and the longitudinal slenderness ratio of the member are calculated respectively, so as to judge the easiness of buckling and deformation of the member in the transverse and longitudinal directions, and the slenderness ratio representing the easy occurrence of instability is used to characterize the critical state of the derrick to be evaluated that is prone to instability. Therefore, in this embodiment, the slenderness ratio representing the easy occurrence of instability is taken as the actual slenderness ratio. The larger the actual slenderness ratio, the easier it is to occur instability. Therefore, when the transverse slenderness ratio is greater than the longitudinal slenderness ratio in this embodiment, the transverse slenderness ratio is taken as the actual slenderness ratio; otherwise, the longitudinal slenderness ratio is taken as the actual slenderness ratio.

[0053] In the embodiment of the present application, the following expressions are used to calculate the transverse slenderness ratio and the longitudinal slenderness ratio respectively:

[0054]

[0055]

[0056] Among them, λ x represents the transverse slenderness ratio, r x represents the transverse radius of gyration, k represents the effective length coefficient of the member in the plane of bending, l represents the length of the member, λ y represents the longitudinal slenderness ratio, r y represents the longitudinal radius of gyration.

[0057] Figure 3 is the schematic diagram of the strain gauge distribution of the member in the method for evaluating the bearing capacity of the derrick of the oil drilling rig in the embodiment of the present application. Figure 4 is the schematic diagram of the cross-sectional parameters of the member in the method for evaluating the bearing capacity of the derrick of the oil drilling rig in the embodiment of the present application. Referring to Figure 3 and Figure 4 , in a specific embodiment of the present application, four strain gauges are pasted on the members constituting the derrick to be evaluated in sequence to collect the stress information of the derrick to be evaluated, and the following expression is used to calculate the first stress of the derrick to be evaluated with the current "H"-shaped cross-section member:

[0058]

[0059]

[0060]

[0061] Among them, f a1 represents the first tensile and compressive stress, f bx1 and f by1respectively represent the first transverse bending stress and the first longitudinal bending stress, σ 1 , σ 2 , σ 3 and σ 4 respectively represent the measured stress values at different positions on the derrick.

[0062] For the "H"-shaped member, the corresponding transverse radius of gyration and longitudinal radius of gyration are calculated using the following expressions:

[0063]

[0064]

[0065] where b represents the width of the connecting rod of the member, h represents the inner width of the member, H represents the outer width of the member, and B represents the height of the member.

[0066] Next, the slenderness ratio critical value is the boundary value for distinguishing elastic buckling and inelastic buckling. Therefore, in this embodiment, the elastic modulus of the member material and the minimum yield stress of the member material are used as the data basis for calculating the slenderness ratio critical value, and the slenderness ratio critical value is obtained using the following expression:

[0067]

[0068] where C c represents the slenderness ratio critical value, E represents the elastic modulus, and F y represents the minimum yield stress.

[0069] Furthermore, in the process of analyzing and comparing the actual slenderness ratio and the slenderness ratio critical value to obtain the maximum axial tensile and compressive stress, according to the magnitude relationship between the actual slenderness ratio and the slenderness ratio critical value, the corresponding maximum axial tensile and compressive stress calculation method is selected to calculate the maximum axial tensile and compressive stress. Specifically, when the actual slenderness ratio is greater than the slenderness ratio critical value, it indicates that a plastic zone will appear when the member on the derrick to be evaluated buckles, and when the actual slenderness ratio is less than the slenderness ratio critical value, it indicates that no plastic zone will appear when the member buckles. Therefore, based on the appearance characteristics of the aforementioned two plastic zones, this embodiment calculates the corresponding maximum axial tensile and compressive stress respectively, so that the final evaluation result is more in line with the actual situation.

[0070] In the embodiment of the present application, if the actual slenderness ratio is greater than the slenderness ratio critical value, the maximum axial tensile and compressive stress is calculated using the following expression:

[0071]

[0072] where F a1 represents the maximum axial tensile and compressive stress when the actual slenderness ratio is greater than the slenderness ratio critical value, E represents the elastic modulus, and λ represents the actual slenderness ratio;

[0073] Alternatively, if the actual slenderness ratio is less than or equal to the critical slenderness ratio, the maximum axial tensile and compressive stress is calculated using the following expression:

[0074]

[0075] where F a2 represents the maximum axial tensile and compressive stress when the actual slenderness ratio is less than or equal to the critical slenderness ratio.

[0076] After obtaining the second stress and the maximum axial tensile and compressive stress, in step S130, the actual bearing capacity of the derrick to be evaluated is determined by comparing the second stress with the maximum axial tensile and compressive stress. In the embodiment of the present application, based on the magnitude relationship between the tensile and compressive stress (the tensile and compressive stress in the second stress) of the member under the maximum hook load designed for the derrick and the allowable axial tensile and compressive stress (the maximum axial tensile and compressive stress) that can be adopted when there is only axial tensile and compressive stress, the actual bearing capacity of the derrick to be evaluated is obtained.

[0077] In the step of determining the actual bearing capacity of the derrick to be evaluated by comparing the second stress with the maximum axial tensile and compressive stress, the ratio of the tensile and compressive stress in the second stress to the maximum axial tensile and compressive stress is calculated, the magnitude relationship between the ratio and the preset bearing capacity determination threshold is determined, and the corresponding calculation method is selected to calculate the bearing capacity strength coefficient used to characterize whether the derrick to be evaluated currently has the ability to bear the maximum static load, so as to calculate the actual bearing capacity of the derrick to be evaluated according to the bearing capacity strength coefficient. Specifically, in this embodiment, the preset bearing capacity determination threshold is used as the evaluation criterion for evaluating whether the derrick to be evaluated can bear the maximum static load, where the preset bearing capacity determination threshold represents the critical ratio between the second stress and the maximum axial tensile and compressive stress when the derrick to be evaluated can bear the maximum static load. Accordingly, by determining the magnitude relationship between the ratio and the preset bearing capacity determination threshold, when the derrick to be evaluated can bear the maximum static load, the bearing capacity strength coefficient used to characterize that the derrick to be evaluated currently has the ability to bear the maximum static load is calculated, or when the derrick to be evaluated cannot bear the maximum static load, the bearing capacity strength coefficient used to characterize that the derrick to be evaluated currently does not have the ability to bear the maximum static load is calculated, and then the actual bearing capacity of the derrick to be evaluated is calculated according to the corresponding bearing capacity strength coefficient. In this embodiment, the preset bearing capacity determination threshold is preferably 0.15.

[0078] In the embodiment of the present application, if the ratio is less than or equal to the preset bearing capacity determination threshold, the first bearing capacity strength coefficient is calculated using the following expression as the current bearing capacity strength coefficient:

[0079]

[0080] where U crepresents the first bearing capacity strength coefficient, f a represents the tensile and compressive stress, F a represents the maximum axial tensile and compressive stress when the actual slenderness ratio is greater than the critical slenderness ratio or the maximum axial tensile and compressive stress when the actual slenderness ratio is less than or equal to the critical slenderness ratio, F bx and F by respectively represent the allowable bending stresses in the transverse direction and the longitudinal direction of the member under the condition of only the existence of bending moment, f bx and f by respectively represent the transverse bending stress and the longitudinal bending stress;

[0081] Alternatively, if the ratio is greater than the preset bearing capacity determination threshold, the second bearing capacity strength coefficient and the third bearing capacity strength coefficient are respectively calculated using the following expressions as the current bearing capacity strength coefficient:

[0082]

[0083]

[0084] wherein, U c1 and U c2 respectively represent the second bearing capacity strength coefficient and the third bearing capacity strength coefficient, C mx and C my respectively represent the stress fitting coefficients in the transverse direction and the longitudinal direction of the member, F’ ex and F’ ey respectively represent the Euler stresses in the transverse direction and the longitudinal direction of the member divided by the safety factor.

[0085] In a specific embodiment of the present application, it is preferred that the stress fitting coefficients C mx and C my in the transverse direction and the longitudinal direction of the member both represent 0.85.

[0086] In the embodiments of the present application, the Euler stresses in the transverse direction and the longitudinal direction of the member divided by the safety factor are calculated using the following expressions:

[0087]

[0088]

[0089] Further, in the process of calculating the actual load-bearing capacity of the derrick to be evaluated according to the load-bearing capacity strength coefficient, when the first load-bearing capacity strength coefficient is less than or equal to 1, or both the second load-bearing capacity strength coefficient and the third load-bearing capacity strength coefficient are less than or equal to 1, it is determined that the current derrick has the ability to bear the maximum static load, and a first bearing capacity parameter is generated to quantitatively characterize the actual load-bearing capacity of the derrick when it has the ability to bear the maximum static load; when the first load-bearing capacity strength coefficient is greater than 1 or any one of the second load-bearing capacity strength coefficient and the third load-bearing capacity strength coefficient is greater than 1, it is determined that the current derrick does not have the ability to bear the maximum static load, and a second bearing capacity parameter is generated to quantitatively characterize the actual load-bearing capacity when the derrick does not have the ability to bear the maximum static load. Specifically, in this embodiment, the load-bearing capacity strength coefficient is used to determine whether the current derrick has the ability to bear the maximum static load, and then based on the determination result, the first bearing capacity parameter or the second bearing capacity parameter for characterizing the actual load-bearing capacity of the derrick is obtained.

[0090] In a specific embodiment of the present application, under the condition of , if U C ≤1, it is determined that the current derrick has the ability to bear the maximum static load; if U C >1, it is determined that the current derrick does not have the ability to bear the maximum static load. Under the condition of , if U C1 ≤1, U C2 ≤1, it is determined that the current derrick has the ability to bear the maximum static load; if U C1 ≤1, U C2 >1, it is determined that the current derrick does not have the ability to bear the maximum static load; if U C1 >1, U C2 ≤1, it is determined that the current derrick does not have the ability to bear the maximum static load; if U C1 >1, U C2 >1, it is determined that the current derrick does not have the ability to bear the maximum static load. After obtaining the determination result of the ability of the current derrick to bear the maximum static load, a first bearing capacity parameter that quantitatively characterizes the actual load-bearing capacity when the derrick has the ability to bear the maximum static load and matches the corresponding condition is generated, and a second bearing capacity parameter that quantitatively characterizes the actual load-bearing capacity when the derrick does not have the ability to bear the maximum static load is generated.

[0091] When it is determined that the current derrick has the ability to bear the maximum static load, a first bearing capacity parameter is generated. Among them, in the process of generating the first bearing capacity parameter, it includes: directly using the maximum static load as the first bearing capacity parameter. The maximum static load in this embodiment is the maximum design hook load of the current derrick to be evaluated, so in this embodiment, the maximum static load is directly used as the first bearing capacity parameter. In other words, when and U C ≤1, and when and U C1 ≤ 1, U C2 ≤ 1, the first bearing capacity parameter is the maximum static load.

[0092] When it is determined that the current derrick does not have the ability to bear the maximum static load, a second bearing capacity parameter is generated. During the generation of the second bearing capacity parameter, when the ratio is less than or equal to the preset bearing capacity determination threshold, the derrick hook load value is obtained by assigning the corresponding bearing capacity strength coefficient as 1, and the current derrick hook load value is used as the second bearing capacity parameter; when the ratio is greater than the preset bearing capacity determination threshold, and the second bearing capacity strength coefficient is less than or equal to / greater than 1, and the third bearing capacity strength coefficient is greater than / less than or equal to 1, the derrick hook load value is obtained by assigning the third bearing capacity strength coefficient / second bearing capacity strength coefficient as 1, and the current hook load value is used as the second bearing capacity parameter; when the ratio is greater than the preset bearing capacity determination threshold, and both the second bearing capacity strength coefficient and the third bearing capacity strength coefficient are greater than 1, the corresponding derrick hook load values are obtained by assigning both the current second bearing capacity strength coefficient and the third bearing capacity strength coefficient as 1, and the smaller derrick hook load value is used as the second bearing capacity parameter.

[0093] Specifically, when and U C > 1, the load data of each strength level with strength lower than the maximum static load in the hook load information is used to calculate the corresponding bearing capacity strength coefficient, so as to fit the correlation between the load and the bearing capacity strength coefficient, and the bearing capacity strength coefficient is assigned as 1. Combining the foregoing correlation, the current maximum bearing capacity of the derrick to be evaluated is obtained. Accordingly, the derrick hook load value representing the current maximum bearing capacity of the derrick to be evaluated is obtained and used as the second bearing capacity parameter.

[0094] When and U C1 ≤ 1, U C2 > 1, the load data of each strength level with strength lower than the maximum static load in the hook load information is used to calculate the corresponding bearing capacity strength coefficient, so as to fit the correlation between the load and the bearing capacity strength coefficient U C2 between, and the bearing capacity strength coefficient U C2 is assigned as 1. Combining the foregoing correlation, the current maximum bearing capacity of the derrick to be evaluated is obtained. Accordingly, the derrick hook load value representing the current maximum bearing capacity of the derrick to be evaluated is obtained and used as the second bearing capacity parameter.

[0095] When and U C1 > 1, U C2When ≤ 1, load data of each strength level with strength lower than the maximum static load in the hook load information is used to calculate the corresponding bearing capacity strength coefficient, so as to fit the correlation between the load and the bearing capacity strength coefficient U C1 between, and assign the bearing capacity strength coefficient U C1 as 1. Combining the aforementioned correlation, the current maximum bearing capacity of the derrick to be evaluated is obtained. Accordingly, the derrick hook load value representing the current maximum bearing capacity of the derrick to be evaluated is obtained and used as the second bearing capacity parameter.

[0096] When and U C1 > 1, U C2 > 1, load data of each strength level with strength lower than the maximum static load in the hook load information is used to calculate the corresponding bearing capacity strength coefficient, so as to respectively fit the correlation between the load and the bearing capacity strength coefficient U C1 and U C2 between, and assign the bearing capacity strength coefficient U C1 and U C2 as 1 respectively. Combining the corresponding correlations mentioned above, the current maximum bearing capacities of the derrick to be evaluated corresponding to U C1 and U C2 are obtained respectively. Accordingly, the derrick hook load values corresponding to U C1 and U C2 are calculated respectively, and the smaller derrick hook load value is used as the second bearing capacity parameter.

[0097] Furthermore, in this embodiment, a preset safety level bearing capacity threshold for evaluating the safety degree of the derrick is also preset in advance. After obtaining the first bearing capacity parameter or the second bearing capacity parameter, based on the preset safety level bearing capacity threshold, the safety level of the derrick to be evaluated is calibrated, so as to generate the safety level information of the current derrick to be evaluated, so as to intuitively reflect the health status of the derrick.

[0098] Example 2

[0099] Based on the bearing capacity evaluation method for the oil drilling rig derrick described in the above-mentioned Embodiment 1, the embodiment of the present invention also provides a bearing capacity evaluation system for the oil drilling rig derrick (hereinafter referred to as "bearing capacity evaluation system"). Figure 5 It is the module block diagram of the bearing capacity evaluation system for the oil drilling rig derrick in the embodiment of the present application.

[0100] As Figure 5As shown in the figure, the bearing capacity evaluation system in the embodiment of the present invention includes: a stress acquisition module 51, a maximum axial tensile and compressive stress calculation module 52, and a bearing capacity evaluation module 53. The stress acquisition module 51 is implemented according to the method described in step S110 above, and is configured to apply load information for simulating the external forces borne by the derrick to be evaluated in its working environment, obtain the first stress of the derrick, and obtain the second stress representing the maximum static load that the derrick to be evaluated can bear based on the first stress; the maximum axial tensile and compressive stress calculation module 52 is implemented according to the method described in step S120 above, and is configured to generate the maximum axial tensile and compressive stress allowed under the condition that only axial tensile and compressive stresses exist in the derrick by using the physical property parameters of the members on the derrick to be evaluated; the bearing capacity evaluation module 53 is implemented according to the method described in step S130 above, and is configured to determine the actual bearing capacity of the derrick to be evaluated by comparing the second stress obtained by the stress acquisition module 51 with the maximum axial tensile and compressive stress calculated by the maximum axial tensile and compressive stress calculation module 52.

[0101] The present invention discloses a method and system for evaluating the bearing capacity of an oil drilling rig derrick. The method first applies load information for simulating the external forces borne by the derrick to be evaluated in its working environment, and then calculates the bearing capacity of the derrick to be evaluated for the maximum static load based on the strength theory and the linear extrapolation principle, so as to obtain the actual bearing capacity of the derrick to be evaluated. The present invention realizes the direct calculation of the bearing capacity of the oil drilling rig derrick, timely reflects the health status of the derrick, provides technical support for taking maintenance and adjustment measures to avoid sudden situations due to the performance degradation of the derrick, and consumes less time and human resources. The present invention does not affect oil drilling and production operations, is not affected by climate and surrounding equipment, can accurately predict the bearing capacity of the in-use oil derrick in real time, and gets rid of the restriction of natural environmental conditions.

[0102] As mentioned above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

[0103] Of course, the present invention may also have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes and deformations should all belong to the protection scope of the claims of the present invention.

[0104] Those skilled in the art should understand that the above-mentioned modules or steps of the present invention can be implemented by a general-purpose computing device. They can be concentrated on a single computing device or distributed on a network composed of multiple computing devices. Optionally, they can be implemented by program codes executable by the computing device, so that they can be stored in a storage device and executed by the computing device, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0105] Although the disclosed embodiments of the present invention are as above, the above content is only an embodiment adopted for the convenience of understanding the present invention and is not intended to limit the present invention. Any person skilled in the art within the technical field to which the present invention pertains may make any modifications and variations in the form of implementation and details without departing from the spirit and scope disclosed by the present invention. However, the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A method for evaluating the bearing capacity of an oil drilling rig derrick, characterized in that, it includes: Applying load information for simulating the external forces borne by the derrick to be evaluated in its working environment to obtain the first stress of the derrick, and based on the first stress, obtaining a second stress characterizing the maximum static load that the derrick to be evaluated can bear; Using the physical property parameters of the members on the derrick to be evaluated to generate the maximum allowable axial tensile and compressive stresses under the condition that only axial tensile and compressive stresses exist in the derrick; Determining the actual bearing capacity of the derrick to be evaluated by comparing the second stress with the maximum axial tensile and compressive stresses.

2. The bearing capacity evaluation method according to claim 1, characterized in that, the first stress includes a first axial tensile and compressive stress, a first transverse bending stress, and a first longitudinal bending stress, wherein, in the step of obtaining a second stress characterizing the maximum static load that the derrick to be evaluated can bear based on the first stress, it includes: Based on the first stress, using the principle of linear extrapolation, respectively predicting the change trends of the first axial tensile and compressive stress, the first transverse bending stress, and the first longitudinal bending stress with the change of load intensity, and extracting the axial tensile and compressive stress, transverse bending stress, and longitudinal bending stress corresponding to the maximum static load from the information of each stress change trend, so as to obtain the second stress.

3. The bearing capacity evaluation method according to claim 1 or 2, characterized in that, in the step of using the physical property parameters of the members on the derrick to be evaluated to generate the maximum allowable axial tensile and compressive stresses under the condition that only axial tensile and compressive stresses exist in the derrick, it includes: Using the physical property parameters and combining with the member connection state parameters to respectively obtain the actual slenderness ratio of the member and the slenderness ratio critical value for distinguishing the elastic buckling state and the inelastic buckling state of the member; Analyzing and comparing the actual slenderness ratio with the slenderness ratio critical value to obtain the maximum axial tensile and compressive stresses.

4. The bearing capacity evaluation method according to claim 3, characterized in that, in the process of obtaining the actual slenderness ratio, it includes: Respectively calculating the transverse slenderness ratio and the longitudinal slenderness ratio of the member, and when the transverse slenderness ratio is greater than the longitudinal slenderness ratio, taking the transverse slenderness ratio as the actual slenderness ratio, otherwise, taking the longitudinal slenderness ratio as the actual slenderness ratio.

5. The bearing capacity evaluation method according to claim 4, characterized in that, using the following expressions to respectively calculate the transverse slenderness ratio and the longitudinal slenderness ratio: Among them, λ x represents the lateral slenderness ratio, r x represents the lateral radius of gyration, k represents the effective length factor of the member in the bending plane, l represents the length of the member, λ y represents the longitudinal slenderness ratio, r y represents the longitudinal radius of gyration.

6. The bearing capacity evaluation method according to any one of claims 3 to 5, characterized in that, using the following expression to obtain the slenderness ratio critical value: Among them, C c represents the slenderness ratio critical value, E represents the elastic modulus, and F y represents the minimum yield stress.

7. The bearing capacity evaluation method according to any one of claims 3 to 6, characterized in that, in the process of analyzing and comparing the actual slenderness ratio with the slenderness ratio critical value to obtain the maximum axial tensile and compressive stresses, it includes: According to the magnitude relationship between the actual slenderness ratio and the slenderness ratio critical value, selecting the corresponding maximum axial tensile and compressive stress calculation method to calculate the maximum axial tensile and compressive stresses, wherein, If the actual slenderness ratio is greater than the critical slenderness ratio, the maximum axial tensile and compressive stress is calculated using the following expression: Among them, F a1 represents the maximum axial tensile and compressive stress when the actual slenderness ratio is greater than the critical slenderness ratio, E represents the elastic modulus, and λ represents the actual slenderness ratio; or If the actual slenderness ratio is less than or equal to the critical slenderness ratio, the maximum axial tensile and compressive stress is calculated using the following expression: Among them, F a2 represents the maximum axial tensile and compressive stress when the actual slenderness ratio is less than or equal to the slenderness ratio critical value, C c represents the slenderness ratio critical value, F y represents the minimum yield stress.

8. The bearing capacity assessment method according to claim 7, characterized in that in the step of determining the actual bearing capacity of the derrick to be assessed by comparing the second stress with the maximum axial tensile and compressive stress, it includes: calculating the ratio of the tensile and compressive stress in the second stress to the maximum axial tensile and compressive stress, determining the magnitude relationship between the ratio and the preset bearing capacity determination threshold, and selecting the corresponding calculation method to calculate the bearing capacity strength coefficient used to characterize whether the derrick to be assessed currently has the ability to bear the maximum static load, so as to calculate the actual bearing capacity of the derrick to be assessed according to the bearing capacity strength coefficient, where if the ratio is less than or equal to the preset bearing capacity determination threshold, the first bearing capacity strength coefficient is calculated using the following expression as the current bearing capacity strength coefficient: Among them, U c represents the first bearing capacity strength coefficient, f a represents the tensile and compressive stress, F a represents the maximum axial tensile and compressive stress when the actual slenderness ratio is greater than the critical slenderness ratio or the maximum axial tensile and compressive stress when the actual slenderness ratio is less than or equal to the critical slenderness ratio, F bx and F by respectively represent the allowable bending stresses in the transverse direction and the longitudinal direction of the member under the condition of only bending moment, f bx and f by respectively represent the transverse bending stress and the longitudinal bending stress; or if the ratio is greater than the preset bearing capacity determination threshold, the second bearing capacity strength coefficient and the third bearing capacity strength coefficient are calculated using the following expressions respectively as the current bearing capacity strength coefficient: Among them, U c1 and U c2 represent the second bearing capacity strength coefficient and the third bearing capacity strength coefficient respectively, C mx and C my represent the stress fitting coefficients in the transverse direction and the longitudinal direction of the member respectively, F′ ex and F′ ey represent the Euler stresses in the transverse direction and the longitudinal direction of the member divided by the safety factor respectively.

9. The bearing capacity assessment method according to claim 8, characterized in that in the process of calculating the actual bearing capacity of the derrick to be assessed according to the bearing capacity strength coefficient, it includes: when the first bearing capacity strength coefficient is less than or equal to 1, or both the second bearing capacity strength coefficient and the third bearing capacity strength coefficient are less than or equal to 1, it is determined that the current derrick has the ability to bear the maximum static load, and a first bearing capacity parameter is generated to quantitatively characterize the actual bearing capacity of the derrick when it has the ability to bear the maximum static load; when the first bearing capacity strength coefficient is greater than 1, or any one of the second bearing capacity strength coefficient and the third bearing capacity strength coefficient is greater than 1, it is determined that the current derrick does not have the ability to bear the maximum static load, and a second bearing capacity parameter is generated to quantitatively characterize the actual bearing capacity when the derrick does not have the ability to bear the maximum static load.

10. The bearing capacity assessment method according to claim 9, characterized in that in the process of generating the first bearing capacity parameter, it includes: directly taking the maximum static load as the first bearing capacity parameter; and in the process of generating the second bearing capacity parameter, it includes: in the case where the ratio is less than or equal to the preset bearing capacity determination threshold, the derrick hook load value is obtained by assigning the corresponding bearing capacity strength coefficient to 1, and the current derrick hook load value is used as the second bearing capacity parameter; in the case where the ratio is greater than the preset bearing capacity determination threshold, and the second bearing capacity strength coefficient is less than or equal to / greater than 1, and the third bearing capacity strength coefficient is greater than / less than or equal to 1, the derrick hook load value is obtained by assigning the third bearing capacity strength coefficient / second bearing capacity strength coefficient to 1, and the current hook load value is used as the second bearing capacity parameter; When the ratio is greater than the preset bearing capacity determination threshold and both the second bearing capacity strength coefficient and the third bearing capacity strength coefficient are greater than 1, the corresponding derrick hook load values are obtained by assigning the current second bearing capacity strength coefficient and the third bearing capacity strength coefficient to 1 respectively, and the smaller derrick hook load value is taken as the second bearing capacity parameter.

11. A bearing capacity evaluation system for an oil drilling rig derrick, characterized in that, the bearing capacity evaluation system includes the following modules: a stress acquisition module, which is configured to apply load information for simulating the external forces borne by a derrick to be evaluated in its working environment, obtain the first stress of the derrick, and obtain the second stress representing the maximum static load that the derrick to be evaluated can bear according to the first stress; a maximum axial tensile and compressive stress calculation module, which is configured to generate the maximum allowable axial tensile and compressive stress under the condition that only axial tensile and compressive stresses exist in the derrick by using the physical property parameters of the members on the derrick to be evaluated; a bearing capacity evaluation module, which is configured to determine the actual bearing capacity of the derrick to be evaluated by comparing the second stress with the maximum axial tensile and compressive stress.

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