An optimized method for assessing the connection quality of two tubular elements

Abstract

A method for connecting threaded portions (3, 4) of a first tubular element (1) and a second tubular element (2) is provided, the method comprising the step of obtaining a tightening graph and further comprising the step of evaluating a connection quality of the first tubular element (1) and the second tubular element (2) based on a first model and a second model by pass / fail of the obtained tightening graph and by assigning a connection status representing a conforming or non-conforming state of the connection of the first tubular element (1) and the second tubular element (2), respectively.

Description

[Technical Field]

[0001] The present invention relates generally to tubular threaded elements, and more particularly to a method for connecting a threaded portion of a first tubular element with a threaded portion of a second tubular element.

[0002] More particularly, the present invention relates to a method for assessing the compatibility of a connection between a threaded portion of a first tubular element and a threaded portion of a second tubular element. [Background technology]

[0003] In the field of oil and gas production, whether at an offshore or onshore facility where well drilling and production operations are carried out, the operations carried out include connecting tubular elements to each other and lowering them down the well to form a drilling string, or an oil or gas production string.

[0004] A male or female threaded portion disposed at one end of a first tubular element may be directly connected to a complementary threaded portion of a second tubular element.

[0005] In another scenario, the first and second tubular elements may be indirectly connected by an intermediate tubular element, such as a joint.

[0006] The tubular elements are assembled within defined constraints to meet the tightening and sealing requirements imposed by the working conditions and to ensure the integrity of the assembly in use throughout its service life.

[0007] However, connections can sometimes be made incorrectly, resulting in poor sealing in the line, damage to the tubular elements, and even premature separation.

[0008] Therefore, the quality of the fastening directly affects the sealing property and lifespan of the tubular element assembly, and therefore the quality of the connection must be evaluated based on whether the fastening is acceptable or not.

[0009] Conventionally, tools for connecting tubular elements include sensors configured to determine the torque applied during tightening and the number of turns of a first tubular element relative to a second tubular element. These tools make it possible to plot a graph (called a "tightening graph") showing the change in the value of the torque as a function of the number of turns during assembly.

[0010] A solution for assessing the quality of the connection between two tubular elements is to have an expert create a tightening chart.

[0011] However, this person may be exposed to risks associated with being on the platform where the connection is made, some criteria may not be clear to the worker, and the above type of assessment is dependent on the worker's skills and therefore may not be sufficiently reliable.

[0012] Other known methods for assessing the connection quality of two tubular elements are automated and based on machine learning. They rely on a number of parameters of the resulting tightening graph.

[0013] Based on the values ​​of these parameters, a connection status of the tubular elements, representing a conforming or non-conforming state, is associated with the tightening graph, which allows defining whether the connection conforms or does not conform to the required specifications.

[0014] However, the probability of an unsatisfactory evaluation remains high. This probability needs to be reduced. Some mismatched connections may be erroneously determined to be properly connected, and vice versa. An improper connection can have dramatic safety and environmental consequences. Techniques for evaluating tubular element connections need to be improved to improve the integrity of the formed string. Summary of the Invention [Problem to be solved by the invention]

[0015] The present invention therefore aims to overcome the above-mentioned drawbacks and relates to a method for connecting tubular threaded elements, which allows the quality of the connection to be evaluated accurately and reliably. [Means for solving the problem]

[0016] Therefore, a method is proposed for connecting a first threaded portion of a first tubular element with a second threaded portion of a second tubular element, wherein the first and second threaded portions have a predetermined optimum torque corresponding to the torque to be reached in the final position of the connection. engaging the first threaded portion with the second threaded portion; rotating the first tubular element relative to the second tubular element to tighten the threaded portion; obtaining a tightening graph showing the torque applied during tightening of the first threaded portion against the second threaded portion to a final position as a function of the amount of relative rotation between the first tubular element and the second tubular element, e.g., as a function of the number of rotations of the first tubular element relative to the second tubular element; Includes:

[0017] The method further includes evaluating the connection quality of the first and second tubular elements based on the first and second models by assigning a pass / fail rating to the obtained tightening graph and a connection status representing a conforming or non-conforming state of the connection between the first and second tubular elements, respectively. The first model is configured to reject the tightening graph when at least one primary numerical variable of the obtained tightening graph is outside a range of reference values ​​associated with the at least one primary numerical variable. The range of reference values ​​represents a conforming state of the connection between the first and second tubular elements. The second model is based on a machine learning-driven algorithm based on a reference variable of a reference tightening graph. The reference tightening graph is stored, for example, in a database. The second model is configured to evaluate the connection quality of the first and second tubular elements as a reference variable when the obtained tightening graph was previously passed by the first model.

[0018] The first model, based on primary numerical variables, allows for a complete interpretation of the graph's failures and allows for accurate identification of the cause of the failure. The second model, based on a machine-learned algorithm, provides a historical summary of tightening curves that were deemed compliant or non-compliant by expert technical judgment. Typically, the second model is a decision algorithm based on a learned numerical model.

[0019] To be able to drive the model, the tightening graph and tightening parameters need to be reduced to a list of numerical variables, called criterion variables, that correlate to the success or failure of the connection. Thus, the second model does not, strictly speaking, use explicit criteria, but rather criterion variables, each of which describes a property of the graph (e.g., area under the curve, torque difference between two points, slope, etc.).

[0020] In this way, the first and second models combined can provide sufficient performance to assess the suitability of the resulting connection.

[0021] Preferably, the training is performed by segmenting a population of initial reference graphs, the suitability of which is determined, for example, by expert technical judgment. A first portion of this population is used for training itself by an algorithm, such as a random forest algorithm. Another portion of this population is used to measure the validity of the predictions of the algorithm trained in this way. This segmentation can be performed repeatedly to statistically confirm the performance of the model. In this way, the second model complements the first model, being able to detect with good accuracy almost all graphs previously rejected by expert technical judgment. The second model not only applies the rules applied by the first model, but also explicitly attempts to reproduce past labeling, thereby detecting more past rejections.

[0022] However, unlike the first model, the decisions of the second model are difficult to interpret, making it difficult to understand why the graph failed. Therefore, preferably, the tightening graph is first evaluated using the first model, and if the tightening graph obtained by the first model is classified as conforming, the tightening graph obtained by the second model is then evaluated. This strategy can empirically provide an optimal balance between detection performance, interpretability of the decisions, and model robustness.

[0023] Advantageously, the primary numerical variables include one or more of the following variables: torque at the final position, torque at the shoulder position where the respective shoulders of the first and second tubular elements come into contact, the amount of relative rotation between the first and second tubular elements between the shoulder position and the final position (e.g., the number of rotations between the shoulder position and the final position), the slope of the graph between the shoulder position and the final position, torque at the sealing position where the respective sealing seats of the first and second tubular elements come into contact, and / or the amount of relative rotation between the first and second tubular elements between the sealing position and the shoulder position (e.g., the number of rotations between the sealing position and the shoulder position).

[0024] Preferably, some of the reference tightening graphs (e.g., reference graphs of the database before training with the second model) are associated with a conforming or non-conforming state of the connection according to the technical judgment of the expert. Further, some of the reference tightening graphs (e.g., reference graphs of the database obtained from training with the second model) are associated with a conforming or non-conforming state of the connection according to training without the technical judgment of the expert.

[0025] According to one embodiment, the criterion variables include one or more secondary numerical variables. The second model evaluates the connection quality of the first tubular element and the second tubular element as a function of the one or more secondary numerical variables. The one or more secondary numerical variables are calculated based on the respective primary numerical variables and minimum and maximum criterion values. The minimum and maximum criterion values ​​define a range of criterion values ​​associated with the primary numerical variables. The one or more secondary numerical variables are calculated according to the following formula:

[0026]

number

[0027] Preferably, the reference variables include one or more standardized variables. Preferably, the second model evaluates the connection quality of the first tubular element and the second tubular element based on one or more standardized variables calculated as a function of each primary numerical variable. The primary numerical variables represent torque. The one or more standardized variables are equal to the ratio of the corresponding primary numerical variable to the optimal torque.

[0028] Advantageously, the reference variable comprises a sum of torque losses between two successive points on the graph. Preferably, the second model is capable of evaluating the connection quality of the first tubular element and the second tubular element as a function of a standardized value of the sum of torque losses between two successive points on the obtained tightening graph. The standardized value is equal to the ratio of the sum of torque losses to the optimal torque.

[0029] Advantageously, the reference variable comprises a gradient between the shoulder position and the final position. Preferably, the second model is capable of evaluating the connection quality of the first tubular element and the second tubular element as a function of the variation of the gradient between the shoulder position and the final position of the obtained tightening graph.

[0030] Advantageously, the reference variable includes a maximum torque loss value between two consecutive points on the graph, the consecutive points being located between the sealing position and the shoulder position and / or between the shoulder position and the final position. Preferably, the second model is capable of evaluating the connection quality of the first tubular element and the second tubular element as a function of a normalized value of the maximum torque loss value between two consecutive points on the obtained tightening graph. The normalized value is equal to the ratio of the maximum torque loss value to the optimal torque.

[0031] Advantageously, the primary numerical variables include a tightening speed. Preferably, the first model is capable of evaluating the connection quality of the first and second tubular elements as a function of the tightening speed during connection of the first and second tubular elements.

[0032] According to one embodiment, the primary variable comprises a loss of linearity of the graph between the shoulder position and the final position. Preferably, the first model is capable of evaluating the connection quality of the first tubular element and the second tubular element as a function of the loss of linearity obtained between the shoulder position and the final position for the obtained tightening graph.

[0033] Advantageously, the primary numerical variable comprises a maximum torque loss value between two successive points of the graph, the two successive points being located between the shoulder position and the final position. Preferably, the first model is capable of evaluating the connection quality of the first tubular element and the second tubular element as a function of a maximum torque loss value between two successive points of the obtained tightening graph, the two successive points being located between the shoulder position and the final position.

[0034] Advantageously, the primary numerical variable comprises the amount of relative rotation between the first and second tubular elements, for example as a number of rotations, during the torque loss occurring between the shoulder position and the final position. Preferably, the first model is capable of evaluating the connection quality of the first and second tubular elements as a function of the amount of relative rotation between the first and second tubular elements during the torque loss occurring between the shoulder position and the final position.

[0035] Advantageously, the primary numerical variable comprises the amount of relative rotation between the first and second tubular elements, for example as a number of rotations, between the engagement position and the final position. The engagement position is the position before the relative rotation between the first and second tubular elements. Preferably, the first model evaluates the connection quality of the first and second tubular elements as a function of the amount of relative rotation between the first and second tubular elements between the engagement position and the final position.

[0036] Advantageously, the primary numerical variable comprises a maximum torque before the sealing position. Preferably, the first model is capable of evaluating the connection quality of the first and second tubular elements as a function of the maximum torque value of the tightening graph obtained before the sealing position. The tightening graph obtained is rejected by the first model when the maximum torque value is above 10% of the optimal torque.

[0037] Preferably, the second model includes one or more of the failure criteria of the first model, i.e. the criterion variables include one or more primary numerical variables. [Brief explanation of the drawings]

[0038] Further objects, advantages and features of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings. [Figure 1A] FIG. 2 is a cross-sectional view of a first tubular element and a second tubular element to be connected in a clamped position. [Figure 1B] FIG. 2 is a cross-sectional view of a first tubular element and a second tubular element to be connected in a sealing position. [Figure 1C] FIG. 1C is a cross-sectional view of a first tubular element and a second tubular element to be connected in a shoulder position. [Figure 2] 10 is a tightening graph showing the torque applied during connection of a first tubular element and a second tubular element as a function of the number of turns by the first tubular element relative to the second tubular element. DETAILED DESCRIPTION OF THE INVENTION

[0039] 1A, 1B and 1C show different steps in the connection of a first tubular element 1 and a second tubular element 2. FIG.

[0040] In the embodiment shown, the tubular element 1 is a sleeve-type junction adapted to connect a second tubular element 2 with a third tubular element (not shown).

[0041] The first tubular element 1 and the second tubular element 2 each comprise a threaded portion 3 and 4, advantageously arranged at one of their ends. The thread 5 of the threaded portion 3 and the thread 6 of the threaded portion 4 are configured to interact.

[0042] Also, the first tubular element 1 comprises a first sealing seat 7 and the second tubular element 2 comprises a second sealing seat 8. The sealing seats are formed from surfaces intended to seal the assembly when the tubular elements 1 and 2 are connected.

[0043] Furthermore, the first tubular element 1 comprises a first shoulder 9 and the second tubular element 2 comprises a second shoulder 10. The shoulders 9 and 10 form stops for fastening.

[0044] The sealing seats 7 and 8 and the shoulders 9 and 10, respectively, are configured to interact with each other.

[0045] There are tubular elements without stops. There are tubular elements without sealing seats. There are tubular elements without stops or sealing seats. The invention is suitable for partial application to the connection of these types of tubular elements and can be applied to the graph section from the start of the connection to the contact between the sealing seats, to the graph section from the contact between the sealing seats to the end of the connection, or to the graph section from the start of the connection to the end of the connection where there is no contact or stop between the sealing seats during the connection.

[0046] To connect two tubular elements 1 and 2, the connection method comprises the step of engaging a first tubular element 1 with a second tubular element 2. More particularly, the connection method comprises the step of engaging a first threaded portion 3 with a second threaded portion 4.

[0047] To tighten the threaded portions 3 and 4 , the first tubular element 1 is rotated relative to the second tubular element 2 .

[0048] The tool used for the connection is a tightening wrench. This tightening wrench is equipped with a gripper and a motor for rotating the first tubular element 1 and the second tubular element 2 relative to each other. The tightening wrench is also equipped with sensors for measuring the number of rotations and the tightening torque. These sensors are connected to an electronic unit, which allows data on torque and rotation, as well as data on the assembly being performed, to be stored. The electronic unit is connected to a processing unit containing processing algorithms. The processing unit is also equipped with a user interface for displaying evaluation results and / or tightening graphs obtained during the connection.

[0049] The method therefore includes a step of obtaining a set of points constituting a tightening graph representing the torque applied during tightening of the first tubular element 1 to its final position as a function of the number of rotations of the first tubular element 1 relative to the second tubular element 2.

[0050] A typical profile of a graph showing the torque applied during tightening as a function of the number of revolutions, known as a torque / revolution graph, is shown in Figure 2. It can be seen that the resulting graph contains three parts with different slopes.

[0051] The first portion 11 corresponds to the engagement of the first tubular element 1 and the second tubular element 2 and the tightening of the threaded portions 3 and 4, as shown in Figure 1A. The threads 5 and 6 gradually come into contact and a higher torque is applied.

[0052] At the contact point R1, the first sealing seat 7 of the first tubular element 1 comes into contact with the second sealing seat 8 of the second tubular element 2. The tubular elements 1 and 2 are then in what is called the sealing position, as shown in Figure 1B.

[0053] The increased friction caused by the contact of the sealing seats 7 and 8 causes a change in the slope, in particular an increase in the applied torque per revolution, resulting in the second part 12 of the graph.

[0054] With continued tightening of the threaded portions 3 and 4, the rotation of the first tubular element 1 relative to the second tubular element 2 reaches the shoulder point Rs. Here, the tubular elements 1 and 2 are in what is called the shoulder position, as shown in FIG. 1C, where the first shoulder 9 of the first tubular element 1 comes into contact with the second shoulder 10 of the second tubular element 2. The increased friction between the respective surfaces of the shoulders 9 and 10 is added to the friction resulting from the contact between the threads 5 and 6 and the friction between the sealing seats 7 and 8, resulting in a change in slope again and a significant increase in the applied torque, resulting in a third portion 13 of the graph extending to the final point Rf where the tubular elements reach their final position.

[0055] In the present invention, the final position means the position of the first tubular element 1 and the second tubular element 2 when the maximum tightening torque is applied and the connection is completed.

[0056] The contact point Rl, the shoulder point Rs, the final point Rf of the tightening graph and the slope coefficient S between the shoulder point Rs and the final point Rf are parameters of the tightening graph that can be taken into account to determine the suitability of the connection of the first tubular element 1 and the second tubular element 2. The value of each of these parameters depends on the type of tubular elements to be connected.

[0057] The slope coefficient S is the ratio of the torque at the shoulder point Ts, the torque at the final point Tf, and the optimum torque T * The slope coefficient can be calculated based on the slope between the shoulder position and the final position, as a function of the optimal torque T * This is defined as the division by the following formula:

[0058]

number

[0059] Optimal Torque T * means the predetermined torque to be reached in the final position, which is specific to the model of the tubular element and the model of the joint to be connected.

[0060] The connection method comprises a step of assessing the connection quality of the first tubular element 1 and the second tubular element 2 based on a failure model of the first and second tightening graphs.

[0061] The first and second models pass or fail the resulting tightening graph as a function of the fail criteria. If the resulting tightening graph is passed, a connection status representative of a conforming state of the connection of the first tubular element 1 and the second tubular element 2 is assigned to the tightening graph. If the resulting tightening graph is failed, a connection status representative of a non-conforming state of the connection of the first tubular element 1 and the second tubular element 2 is assigned to the tightening graph.

[0062] The automation resulting from the assessment of the connection quality of the tubular elements by the first and second models allows to eliminate the human factor during the assessment of the conformity of the connection and thus improves the accuracy of the assessment.

[0063] The first model is configured to reject the tightening graph when the value of at least one primary numerical variable A of the obtained tightening graph deviates from a range of reference values ​​representing the compatibility state of the connection of the first tubular element 1 and the second tubular element 2.

[0064] The first model can rely on an algorithm.

[0065] The second model is based on an algorithm driven by machine learning or artificial intelligence. In particular, the algorithm is driven based on reference variables of a reference tightening graph stored in a database.

[0066] Each of the reference variables considered in the algorithm of the second model represents a feature of the tightening graph.

[0067] When the obtained tightening graph has previously been passed by the first model, the second model evaluates the connection quality of the first tubular element 1 and the second tubular element 2 to confirm or deny the passing of the tightening graph by the first model.

[0068] That is, the evaluation of the connection quality of the first tubular element 1 and the second tubular element 2 is carried out in a first step by a first failing model, and in a second step by a second model when the tightening graph has previously been passed by the first model.

[0069] The primary numerical variable A may be determined on the tightening graph based on parameters including the contact point Rl, the shoulder point Rs, the final point Rf, and / or the slope coefficient S between the shoulder point Rs and the final point Rf on the tightening graph.

[0070] In the illustrated embodiment, the primary numerical variables A considered by the first model are the torque at the final position Tf, the torque at the shoulder position Ts, the rotational speed ΔR between the shoulder position and the final position. s-f , and a slope coefficient S.

[0071] According to one embodiment, the torque Tl at the sealing position and the number of rotations ΔR between the sealing position and the shoulder position are l-s Other primary numeric variables A can be considered, such as:

[0072] For each of the primary numerical variables A considered, a minimum criterion A min and maximum reference value A max The range of reference values ​​is then determined, which is representative of the compatibility of the connection of the first tubular element 1 and the second tubular element 2.

[0073] According to one embodiment, the minimum reference value A min and maximum reference value A maxcan be determined based on a reference graph that is stored in a database and associated with a connection status representing a compatible or incompatible state of the connection of a reference first tubular element and a reference second tubular element for each type of tubular element and model of the joint to be connected.

[0074] A reference graph that is successfully connected is associated with a conforming state, and conversely, a reference graph that fails to connect is associated with an unconforming state.

[0075] Preferably, the reference tightening graphs are stored in a database. These reference graphs in the database are associated with a conforming or non-conforming state of the connection, preferably according to the technical judgment of an expert. If the connection proves to be successful, the expert can associate a "conforming" status with the obtained reference graph, thereby passing the connection of the reference tubular elements. Conversely, if the connection proves to be unsuccessful, the expert can associate a "non-conforming" status with the obtained reference graph, thereby failing the connection of the reference tubular elements. In this way, a reliable and comprehensive database can be obtained.

[0076] In the illustrated embodiment, the first model is a function of the torque at the final position Tf, the torque at the shoulder position Ts, the number of rotations ΔR between the shoulder position and the final position. s-f , and the slope coefficient S are respectively associated with the minimum reference value A min or the associated maximum reference value A max If the tightening graph exceeds the

[0077] To improve the accuracy of the assessment of the connection, additional rejection criteria can be incorporated into the first model.

[0078] Advantageously, the first model is able to evaluate the connection quality of the first tubular element 1 and the second tubular element 2 as a function of the tightening speed, where too high a speed, especially at the shoulder, may indicate a poor connection.

[0079] Preferably, the tightening graph is rejected when the tightening speed exceeds a predetermined threshold (eg, 5 revolutions per minute).

[0080] According to one embodiment, the rejection criteria for the first model can be based on determining a loss of linearity between the shoulder position and the final position, which, in particular, can indicate plastic deformation and slippage.

[0081] Linear interpolation can be performed by plotting a straight line between the shoulder point Rs and the final point Rf, passing through the 25% and 75% indexes. Then, the maximum distance between the tightening graph obtained during the connection method and the straight line is calculated.

[0082] The loss of linearity is the average deviation of the graph from the linear interpolation of the optimum torque T * Preferably, the absolute value of the mean deviation is calculated by an algorithm driven by machine learning, which results in a high coefficient of oscillation due to linear interpolation, making it easier to determine.

[0083] When the distance gained by this loss of linearity exceeds a predetermined threshold, the tightening graph is rejected.

[0084] Advantageously, the first model is capable of evaluating the connection quality of the first tubular element 1 and the second tubular element 2 as a function of the maximum torque loss value between two consecutive points of the tightening graph obtained between the shoulder position and the final position.

[0085] In particular, the determination of the maximum torque loss value is advantageous for detecting slip-related connection defects and can generally indicate the appearance of noise in the power cable.

[0086] The maximum torque loss value means the maximum torque loss determined on the tightening graph.

[0087] Advantageously, the rejection criterion of the first model may be based on the number of revolutions made during the torque loss that occurs between the shoulder position and the final position.

[0088] A short-term torque loss may simply correspond to an artifact, however, if the number of revolutions made during the torque loss exceeds a predetermined threshold, the torque loss can be interpreted as the occurrence of a fault resulting in a mismatched connection.

[0089] Advantageously, the first model is capable of evaluating the connection quality of the first tubular element 1 and the second tubular element 2 as a function of the number of rotations Rf at the final position in order to reject graphs that are too short, indicating an incompatible state of the connection.

[0090] For example, a tightening graph may be rejected when the number of revolutions Rf at the final position is below a predetermined threshold (eg, equal to one revolution).

[0091] Advantageously, the first model evaluates the connection quality of the first tubular element and the second tubular element as a function of the value of the maximum torque before the sealing position. The tightening graph obtained shows the connection quality of the first tubular element and the second tubular element as a function of the value of the maximum torque before the sealing position. * is rejected by the first model when it exceeds 10% of the

[0092] The first model is a combination of numerical criteria that represent distinct causes of failure in the tightening graph. Each of these failure criteria is calculated based on a numerical criterion and a minimum or maximum threshold value for that criterion. This first model is adaptive and can identify failure scenarios that correspond to the most frequent problems that occur when connecting two tubular elements 1, 2. It can also identify the cause of failure and the level at which the threshold is exceeded, and is fully interpretable.

[0093] Preferably, when the first model fails the tightening graph, the failure criteria on which the assignment of a status representing a non-conforming condition is based is displayed to notify the operator of the specific cause.

[0094] Also preferably, the second model is capable of evaluating the connection quality of the first tubular element and the second tubular element as a function of one or more secondary numerical variables B. Each of the secondary numerical variables B is related to the primary numerical variable A and a minimum reference value A that defines a range of reference values ​​according to the following formula: min and maximum reference value A max It is calculated based on:

[0095]

number

[0096] The calculated secondary numeric variable B is used to calculate the minimum reference value A. min and maximum reference value A max The deviation of the primary numerical variable A from the range of reference values ​​defined by can be measured more easily and with higher sensitivity. If the calculated secondary numerical variable B is below 0 or above 1, this means that the primary numerical variable A is not included in the range of reference values. The algorithm rejects the tightening graph, which is associated with a non-conforming state of the connection.

[0097] As a result, finer and more reliable discrimination regarding fastening quality is possible across various joint models.

[0098] In the illustrated embodiment, the secondary numerical variable B is a torque Tf at the final position, a torque Ts at the shoulder position, and a rotation speed ΔR between the shoulder position and the final position. s-f , and a slope coefficient S.

[0099] For example, the secondary numerical variable Bf related to the final torque is calculated according to the following formula:

[0100]

number

[0101] Preferably, the second model is capable of evaluating the connection quality of the first tubular element 1 and the second tubular element 2 based on one or more standardized variables C. The standardized variables C are calculated as a function of a linear numerical variable A representing the torque. The standardized variables are used to estimate the optimum torque T * It is equal to the ratio of the primary numeric variable A to . It is defined by the following formula:

[0102]

number

[0103] For example, the normalized variable related to the final torque is calculated according to the following formula:

[0104]

number

[0105] In the illustrated embodiment, the normalized variable C is the torque at the final position Tf, the torque at the shoulder position Ts, the torque at the sealing position Tl, the delta torque ΔT between the sealing position and the shoulder position l-s and the delta torque ΔT between the shoulder position and the final position s-f It is calculated based on:

[0106] Delta torque ΔT between the sealing position and the shoulder position l-scorresponds to the difference in torque value measured between the sealing position and the shoulder position.

[0107] Preferably, the second model is capable of rejecting the tightening graph as a function of the sum of the torque losses between two consecutive points on the tightening graph obtained, which makes it possible to detect, in particular, interferences in the threads. In this context, the normalized value is calculated by multiplying the calculated sum of the torque losses by a predetermined optimum torque T. * It is calculated and defined by dividing by

[0108] Advantageously, the second model is capable of evaluating the connection quality of the first tubular element 1 and the second tubular element 2 as a function of the variation of the slope after the shoulder position of the obtained tightening graph.

[0109] The slope variation is the deviation from the list defined by the slope between the shoulder position and the final position of the obtained tightening graph, which is the optimum torque T. * It is equal to divided by.

[0110] Advantageously, the second model can evaluate the connection quality of the first tubular element 1 and the second tubular element 2 as the maximum torque loss value between two consecutive points of the tightening graph obtained between the sealing position and the shoulder position and / or between the shoulder position and the final position.

[0111] Further advantageously, the rejection criterion based on maximum torque loss is based on the optimum torque T * The torque loss can be evaluated based on a normalized value equal to the ratio of the maximum torque loss value to the

[0112] Additionally, the failure criteria based on maximum torque loss may be evaluated based on a normalized value equal to the ratio of the maximum torque loss value to the shoulder torque Ts.

[0113] Furthermore, the second model can evaluate the connection quality of the first tubular element 1 and the second tubular element 2 as a function of the maximum torque value before the sealing position and / or between the sealing position and the shoulder position. The tightening graph can be used to determine the connection quality of the first tubular element 1 and the second tubular element 2 as a function of the maximum torque value before the sealing position and / or between the sealing position and the shoulder position. * is rejected by the second model when it exceeds 10% of the

[0114] Preferably, the normalized value is defined as the maximum torque divided by the shoulder torque Ts, where a high value can indicate a problem with the joint.

[0115] Furthermore, the rejection criterion for the second model is the value of the area defined between the graph and the X-axis, i.e., the number of revolutions for the last two revolutions is the optimum torque T * This can be based on the value divided by . This allows to specifically reject tightening graphs that do not have a contact point Rl or a shoulder point Rs.

[0116] The second model is based on a machine learning driven algorithm. To drive the model, the tightening graph and tightening parameters are reduced to a list of criterion variables that correlate with tightening success or failure. Each criterion variable represents a feature of the tightening graph.

[0117] Preferably, from a performance standpoint, the second model includes one or more of the failure criteria of the first model. Increasing the number of variables describing the graph makes it easier for the algorithm to classify the graph. Training is then performed on a database of reference tightening graphs.

[0118] The method for connecting a first tubular element 1 and a second tubular element 2 can include a step of assessing the connection quality as a function of a rejection criterion specific thereto, and then establishing a score by means of a second model.

[0119] For example, if the score of the second model is above a predetermined threshold, the tightening graph is rejected. Conversely, if the score is below the threshold, the tightening graph is passed.

[0120] This second machine learning model is able to detect with very high accuracy almost all of the tightening graphs that were rejected by the first model.

[0121] The first and second models are complementary and are able to detect approximately 70% and 99% of failure scenarios, respectively. This strategy of evaluating the connection quality of the two tubular elements empirically provides an optimal balance between detection performance, interpretability of the decisions, and robustness of the overall model.

[0122] This combination allows for the detection of almost all non-compliant connections in an automated manner, without human intervention.

Claims

1. A method for connecting a first threaded portion (3) of a first tubular element (1) with a second threaded portion (4) of a second tubular element (2), wherein said first threaded portion (3) and said second threaded portion (4) are threaded to a predetermined optimum torque (T) corresponding to the torque to be reached in the final position of the connection. ＊ ) wherein the method comprises: engaging the first threaded portion (3) with the second threaded portion (4); rotating the first tubular element (1) relative to the second tubular element (2) to tighten the first threaded portion (3) and the second threaded portion (4); obtaining a tightening graph showing the torque applied during tightening of the first threaded portion (3) onto the second threaded portion (4) to the final position as a function of the amount of relative rotation between the first tubular element (1) and the second tubular element (2); Including, evaluating the connection quality of the first tubular element (1) and the second tubular element (2) based on a first model and a second model by passing or failing the obtained tightening graph and by assigning a connection status representing a conforming or non-conforming state of the connection of the first tubular element (1) and the second tubular element (2), the first model is configured to reject the tightening graph when at least one primary numerical variable (A) of the obtained tightening graph is outside a range of reference values ​​associated with the at least one primary numerical variable (A), the range of reference values ​​representing a compatibility state of the connection of the first tubular element (1) and the second tubular element (2); the second model is based on an algorithm driven by machine learning based on reference variables of a reference tightening graph, the second model being configured to evaluate the connection quality of the first tubular element (1) and the second tubular element (2) as a function of the reference variables when the obtained tightening graph has previously been passed by the first model, The reference variables include one or more secondary numerical variables (B), and the second model evaluates the connection quality of the first tubular element and the second tubular element as a function of the one or more secondary numerical variables (B), the one or more secondary numerical variables (B) being calculated based on each of the primary numerical variables (A) and a minimum reference value (A min ) and a maximum reference value (A max ), the minimum reference value (A min ) and the maximum reference value (A max ) defining a range of reference values ​​associated with the primary numerical variable (A), and the one or more secondary numerical variables (B) being calculated according to the following formula: [Equation 7] where B represents the secondary numerical variable, A represents the primary numerical variable, A min represents the minimum reference value equal to the lower limit of the range of reference values ​​associated with the primary numerical variable, and A max represents the maximum reference value equal to the upper limit of the range of reference values ​​associated with the primary numerical variable. method.

2. The primary numerical variable (A) is a torque (Tf) at the final position, a torque (Ts) at a shoulder position where the shoulders (9, 10) of the first tubular element (1) and the second tubular element (2) come into contact, and a relative rotation amount (ΔR) between the first tubular element (1) and the second tubular element (2) between the shoulder position and the final position. ｓ－ｆ ), the slope of the tightening graph between the shoulder position and the final position, the torque (Tl) at the sealing position where the sealing seats (7, 8) of the first tubular element and the second tubular element come into contact, and / or the amount of relative rotation (ΔR ｌ－ｓ 2. The method of claim 1, wherein the variable comprises one or more of the following:

3. 3. The method of claim 2, wherein the reference variable comprises a gradient between the shoulder position and the final position, and the second model evaluates the connection quality of the first tubular element and the second tubular element as a function of variation in the gradient between the shoulder position and the final position of the obtained tightening graph.

4. The reference variables include a maximum torque loss value between two consecutive points of the tightening graph, the two consecutive points being located between the sealing position and the shoulder position and / or between the shoulder position and the final position, and the second model evaluates the connection quality of the first tubular element (1) and the second tubular element (2) as a function of a standardized value of the maximum torque loss value between the two consecutive points of the obtained tightening graph, the standardized value being a function of the optimum torque (T ＊ 4. The method of claim 2 or 3, wherein the ratio of the maximum torque loss value to the maximum torque loss value is equal to the ratio of the maximum torque loss value to the maximum torque loss value.

5. 3. The method according to claim 2, wherein the primary numerical variable (A) comprises a loss of linearity of the tightening graph between the shoulder position and the final position, and the first model evaluates the connection quality of the first tubular element (1) and the second tubular element (2) for the obtained tightening graph as a function of the loss of linearity obtained between the shoulder position and the final position.

6. 3. The method of claim 2, wherein the primary numerical variable (A) includes a relative rotation amount between the first tubular element (1) and the second tubular element (2) during a torque loss occurring between the shoulder position and the final position, and the first model evaluates the connection quality of the first tubular element (1) and the second tubular element (2) as a function of the relative rotation amount between the first tubular element (1) and the second tubular element (2) during a torque loss occurring between the shoulder position and the final position.

7. 3. The method of claim 2, wherein the primary numerical variable (A) comprises a relative rotation amount between the first tubular element (1) and the second tubular element (2) between an engagement position and the final position, the engagement position being a position before relative rotation between the first tubular element (1) and the second tubular element (2), and the first model evaluates the connection quality of the first tubular element (1) and the second tubular element (2) as a function of the relative rotation amount between the first tubular element (1) and the second tubular element (2) between the engagement position and the final position.

8. The primary numerical variable (A) comprises a maximum torque value before the sealing position, and the first model evaluates the connection quality of the first tubular element (1) and the second tubular element (2) as a function of the maximum torque value of the tightening graph obtained before the sealing position, and the tightening graph obtained is such that the maximum torque value is equal to the optimum torque (T ＊ 3. The method of claim 2, wherein the first model is rejected when the first model exceeds 10% of the first model.

9. 7. The method according to claim 2, wherein the primary numerical variable (A) comprises a maximum torque loss value between two consecutive points of the tightening graph, the two consecutive points being located between the shoulder position and the final position, and the first model evaluates the connection quality of the first tubular element (1) and the second tubular element (2) as a function of the maximum torque loss value between two consecutive points of the obtained tightening graph.

10. The method of claim 1 , wherein a portion of the baseline tightening graph is associated with a conforming or non-conforming state of the connection according to expert engineering judgment.

11. The reference variables include one or more standardized variables (C), and the second model evaluates the connection quality of the first tubular element and the second tubular element based on the one or more standardized variables (C) calculated as a function of each of the primary numerical variables (A), the primary numerical variables (A) representing torque, and the one or more standardized variables (C) representing the optimum torque (T ＊ 2. The method of claim 1, wherein the ratio of the corresponding primary numerical variable (A) to the corresponding primary numerical variable (A).

12. The reference variable comprises a sum of torque losses between two successive points of the tightening graph, and the second model evaluates the connection quality of the first tubular element (1) and the second tubular element (2) as a function of a standardized value of the sum of torque losses between two successive points of the obtained tightening graph, and the standardized value is used to determine the optimum torque (T ＊ 2. The method of claim 1, wherein the calculated torque loss is equal to the ratio of the sum of the calculated torque losses to the calculated torque loss.

13. 2. The method of claim 1, wherein the primary numerical variable (A) comprises a tightening speed, and the first model evaluates the connection quality of the first tubular element (1) and the second tubular element (2) as a function of the tightening speed during connection of the first tubular element (1) and the second tubular element (2).

14. The method of claim 1 , wherein the second model includes one or more rejection criteria of the first model.

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