A sleeve type electronic cabin structure of a logging while drilling instrument and a strength checking method thereof

Abstract

The application belongs to the technical field of logging while drilling, and discloses a sleeve type electronic cabin structure of a logging while drilling instrument and a strength checking method thereof. The sleeve type electronic cabin structure of the logging while drilling instrument comprises a drill collar male head, a drill collar female head threadedly connected with the drill collar male head, and a sleeve arranged on the drill collar male head and located between a male head shoulder of the drill collar male head and a female head shoulder of the drill collar female head. The length L of the sleeve is L0+A+B, wherein L0 is the distance between the male head shoulder and the female head shoulder when the drill collar female head is connected with the drill collar male head and the sleeve is not installed, A is a sleeve length compensation value under the action of a threaded axial force F, and B is a sleeve length compensation value caused by a threaded fit clearance. The sleeve type electronic cabin structure of the logging while drilling instrument can keep the contact end surfaces of the sleeve and the drill collar male head and the contact end surfaces of the sleeve and the drill collar female head in the sleeve type electronic cabin structure of the logging while drilling instrument sealed at all times.

Description

Technical Field

[0001] This invention relates to the field of logging while drilling technology, specifically to a sleeve-type electronic cabin structure for logging while drilling instruments and its strength verification method. Background Technology

[0002] Logging while drilling (LOW) refers to the process by which logging instruments measure downhole engineering and geological parameters during drilling and transmit the results to the surface in real time for processing using a data transmission system. The instruments that perform these measurement functions are called LOW instruments. Therefore, LOW instruments also function as drill collars while performing logging operations. LOW instruments are structurally more complex than ordinary drill collars, for example… Figure 1 As shown, a portion of the drill collar wall thickness needs to be removed to create space (i.e., the electronics compartment 4') for housing circuit boards and sensors, etc. The existing electronics compartment structure 100' can be arranged near the male drill collar head 1' and near the female drill collar head 2'; these two forms are respectively called a sleeve-type electronics compartment structure and an insert-type electronics compartment structure.

[0003] like Figure 1 As shown, the connection between the male drill collar 1' and the female drill collar 2' is achieved through a rotary shoulder thread 3', which is a tapered thread with a shoulder surface on both the male and female threads. This rotary shoulder thread 3' serves both a connection and a seal. When tightened to the specified torque, the shoulder surface of a standard rotary shoulder thread 3' is compressed by the axial force of the thread, thus creating a seal. When tightened to the rated torque, the standard rotary shoulder thread 3' distributes the torque value proportionally between the threaded joint and the shoulder. However, as... Figure 2 As shown, the sleeve-type electronic compartment structure 100” modifies the standard rotating shoulder thread 3', so that the shoulder surface of the threaded male end 1 is moved away by a certain distance, and then the sleeve 6 is used to compensate for the distance the shoulder is moved away. The contact end face of the sleeve 6 and the drill collar female end 2, as well as the contact end face of the sleeve 6 and the drill collar male end 1, are subjected to the thread axial force, thereby forming contact pressure to achieve the sealing effect.

[0004] However, as Figure 3 As shown, during the process of the logging-while-drilling instrument entering the curved wellbore 200, when the degree of curvature of the logging-while-drilling instrument is large, the contact end face between the sleeve 6 and the drill collar female head 2, as well as the contact end face between the sleeve 6 and the drill collar male head 1, may separate, thereby losing the sealing function. Ultimately, this will lead to damage to the circuit boards and sensors and other components inside the logging-while-drilling instrument sleeve-type electronic compartment structure 100". Summary of the Invention

[0005] To ensure that the contact surfaces between the sleeve and the male drill collar, as well as the contact surfaces between the sleeve and the female drill collar, in the sleeve-type electronic compartment structure of the logging-while-drilling instrument can always maintain a sealing effect, this invention proposes a sleeve-type electronic compartment structure for logging-while-drilling instruments and its strength verification method.

[0006] The logging-while-drilling instrument sleeve-type electronic compartment structure according to the present invention includes: a drill collar male head, a drill collar female head threadedly connected to the drill collar male head, and a sleeve sleeved on the drill collar male head and located between the male head shoulder of the drill collar male head and the female head shoulder of the drill collar female head, wherein the length of the sleeve L = L0 + A + B, where L0 is the distance between the male head shoulder and the female head shoulder when the drill collar female head and the drill collar male head are connected and the sleeve is not installed, A is the sleeve length compensation value under the action of the thread axial force F, and B is the sleeve length compensation value caused by the thread fit clearance.

[0007] Furthermore, the sleeve length compensation value A under the action of the thread axial force F is the sum of the value of the sleeve being compressed and shortened by the thread axial force F and the value of the drill collar male being stretched.

[0008] Furthermore, the formula for calculating the axial force F of the thread is:

[0009]

[0010] Where θ is half of the tooth angle, P is the pitch, f is the coefficient of friction, and R... t Rs is half the thread pitch diameter at 1 / 2 of the thread engagement length, Rs is half the center diameter of the shoulder contact ring, and T is the torque applied to the thread.

[0011] Furthermore, the sleeve length compensation value A under the action of thread axial force F is obtained through finite element analysis: when thread axial force F is applied to the end face of the drill collar and the end face of the sleeve respectively, the displacement values ​​of the two end faces are obtained respectively. The sleeve length compensation value A under the action of thread axial force F is the sum of the absolute values ​​of the average values ​​of the two end face displacement values.

[0012] Furthermore, the formula for calculating the sleeve length compensation value B caused by the thread fit clearance is as follows:

[0013] B = δ × φ,

[0014] Where δ is the clearance between the male and female threads, and φ is the thread taper.

[0015] The strength verification method for the sleeve-type electronic compartment structure of the logging-while-drilling instrument according to the present invention includes the following steps:

[0016] Step S1: Calculate and determine the length L of the sleeve, where L = L0 + A + B, where L0 is the distance between the male shoulder of the drill collar and the female shoulder of the drill collar when the female drill collar is connected to the male drill collar and the sleeve is not installed, A is the sleeve length compensation value under the action of the thread axial force F, and B is the sleeve length compensation value caused by the thread fit clearance.

[0017] Step S2: Based on the length L0 of the sleeve, establish an assembly model of the sleeve-type electronic cabin structure of the logging-while-drilling instrument, and apply working condition parameters to the assembly model to simulate the real working environment of the assembly model. The working condition parameters include: the preset working parameters of the assembly model and the boundary condition parameters set for the assembly model.

[0018] Step S3: Obtain the equivalent stress distribution diagram of the assembly model to determine whether the sleeve-type electronic cabin structure of the logging-while-drilling instrument meets the strength requirements.

[0019] Furthermore, in step S1, the sleeve length compensation value A under the action of the thread axial force F is obtained through finite element analysis: the thread axial force F is applied to the drill collar end face and the sleeve end face respectively, and the displacement values ​​of the two end faces are obtained. The compensation value A is the sum of the absolute values ​​of the average values ​​of the two end face displacement values.

[0020] Furthermore, in step S2, the preset working parameters of the assembly model include: the working torque N of the logging-while-drilling instrument during drilling, the dogleg degree M, the rated tightening torque T of the thread, the length C of the sleeve-type electronic cabin structure of the logging-while-drilling instrument, and the loading angle E.

[0021] Furthermore, the formula for calculating the loading angle E is:

[0022]

[0023] Further, in step S2, the boundary condition parameters set for the assembly model include: setting boundary condition one for one end face of the sleeve-type electronic cabin structure of the logging-while-drilling instrument: the movement in the X, Y, and Z directions is set to 0, the rotation in the X and Y directions is set to 0, and the rotation angle in the Z direction is set to E; setting boundary condition two for the other end face of the sleeve-type electronic cabin structure of the logging-while-drilling instrument: the rotation in the Z direction is set to E, the remaining degrees of freedom are released, and the torque in the X direction is N; the contact between each part is set according to the actual relationship, wherein the sleeve end face and the drill collar end face are set with an interference offset, the value of which is A+B.

[0024] Compared with the prior art, the electronic cabin structure of the logging-while-drilling instrument of the present invention compensates for the length of the sleeve. This compensation is due to two factors: the compensation value A caused by the axial force F of the thread and the compensation value B caused by the thread fit clearance. This ensures that the contact end faces of the sleeve and the drill collar male head and the sleeve and the drill collar female head of the logging-while-drilling instrument electronic cabin structure can always maintain a sealing effect during downhole service. At the same time, it can also prevent the female thread from cracking and the thread side from sticking due to greater pressure, thus effectively improving the service life and reliability of the electronic cabin structure of the logging-while-drilling instrument of the present invention. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the electronic compartment structure of a logging-while-drilling instrument in the prior art, showing the standard threaded fit between the male and female drill collars;

[0026] Figure 2 This is a structural diagram of a sleeve-type electronic compartment structure for logging-while-drilling instruments in the prior art.

[0027] Figure 3 This is a schematic diagram of the bending of a logging-while-drilling instrument with a sleeve-type electronic cabin structure when it enters a curved well.

[0028] Figure 4 This is a schematic diagram of the sleeve-type electronic compartment structure of the logging-while-drilling instrument according to an embodiment of the present invention;

[0029] Figure 5 The rotating shoulder threaded fit between the male and female drill collar heads in the sleeve-type electronic compartment structure of the logging-while-drilling instrument according to an embodiment of the present invention;

[0030] Figure 6 for Figure 4 The diagram shows the threaded axial force action of the sleeve-type electronic compartment structure of the logging-while-drilling instrument.

[0031] Figure 7 This is a displacement diagram of the threaded shoulder end face in the sleeve-type electronic compartment structure of the logging-while-drilling instrument according to an embodiment of the present invention.

[0032] Figure 8 This is a schematic diagram illustrating the application of boundary conditions to the sleeve-type electronic compartment structure of the logging-while-drilling instrument according to an embodiment of the present invention.

[0033] Figure 9 for Figure 8 The stress distribution diagram shows the stress magnitude of the sleeve-type electronic cabin structure of the logging-while-drilling instrument under the boundary conditions shown. Detailed Implementation

[0034] To better understand the purpose, structure, and function of this invention, the invention will be described in further detail below with reference to the accompanying drawings.

[0035] Figure 4 The structure of a sleeve-type electronic cabin structure 100 for logging-while-drilling instruments according to an embodiment of the present invention is shown. (Combined with...) Figure 4 and Figure 6 As shown, the logging-while-drilling instrument sleeve-type electronic compartment structure 100 may include: a drill collar male head 1, a drill collar female head 2 connected to the drill collar male head 1 via a rotating shoulder thread 3, and a sleeve 6 sleeved on the drill collar male head 1 and located between the male shoulder of the drill collar male head 1 and the female shoulder of the drill collar female head 2. An electronic compartment 4 for holding circuit boards and sensors is formed between the sleeve 6 and the drill collar male head. The length L of the sleeve 6 is L0 + A + B, where L0 is the distance between the male shoulder and the female shoulder when the drill collar female head 2 is connected to the drill collar male head 1 and the sleeve 6 is not installed, A is the sleeve length compensation value under the action of the thread axial force F, and B is the sleeve length compensation value caused by the thread fit clearance.

[0036] In existing technologies, such as Figure 2 As shown, after the drill collar female head 2 is tightened relative to the drill collar male head 1 with the rated thread torque, if the length of the sleeve 6 is not compensated, the actual length of the sleeve 6 will be less than L0 after compression. At this time, the threaded pair will rotate more to compensate for the axial distance. Due to the certain taper angle of the thread, the threaded female head has more expansion than originally designed, and the threaded male head has more compression than originally designed. The ratio of torque distributed between the threaded pair and the shoulder surface changes. The torque distributed on the threaded pair will increase, and the torque distributed on the shoulder surface will decrease. With such a structure, after working in the curved downhole environment, the threaded female thread will be more prone to cracking, and the thread tooth side will be under greater pressure, which may cause sticking and prevent the thread from being properly loosened. At the same time, the contact stress between the contact end faces of the sleeve and the drill collar male head, and between the sleeve and the drill collar female head, will decrease, resulting in a decrease in sealing ability. To maintain consistent performance with standard thread designs, ensuring a consistent seal between the contact surfaces of the sleeve and the drill collar male and female heads in the logging-while-drilling instrument sleeve-type electronic cabin structure, and to guarantee the service life and reliability of the logging-while-drilling instrument sleeve-type electronic cabin structure 100, this invention compensates for the length of the sleeve 6. This compensation is achieved through two parts: a compensation value A resulting from the axial force F of the thread, and a compensation value B resulting from the thread fit clearance.

[0037] According to the present invention, the sleeve length compensation value A under the action of the thread axial force F is the sum of the value at which the sleeve 6 is compressed and shortened by the thread axial force F and the value at which the drill collar male head 1 is stretched. The formula for calculating the thread axial force F is:

[0038]

[0039] Among them, such as Figure 5 As shown, θ is half the tooth angle, P is the pitch, f is the coefficient of friction, and R... t Rs is half the thread pitch diameter at 1 / 2 of the thread engagement length, Rs is half the center diameter of the shoulder contact ring, and T is the torque applied to the thread.

[0040] Furthermore, such as Figure 6 As shown, the sleeve length compensation value A under the action of thread axial force F can be obtained through finite element analysis: the thread axial force F is applied to the end face of the drill collar and the end face of the sleeve 6 respectively, and the displacement values ​​of the two end faces are obtained respectively. The sleeve length compensation value A under the action of thread axial force F is the sum of the absolute values ​​of the average values ​​of the two end face displacement values.

[0041] For example, the specific values ​​in the structure of a certain instrument are: Rs = 79.625 mm; Rt = 56.375 mm; P = 8.5 mm; θ = 30°; f = 0.08; T = 34000 Nm. The result is F = 2615 kN.

[0042] Take half of the model, and in the assembly environment, apply a force of 1307.5 kN to both the end face of the drill collar and the end face of the sleeve, and obtain the displacement values ​​of the two end faces, such as... Figure 7 As shown, the compensation value A is the sum of the absolute values ​​of the average values ​​of the two end face displacements, which is 1.9 mm.

[0043] According to the present invention, the formula for calculating the sleeve length compensation value B caused by the thread fit clearance is as follows:

[0044] B = δ × φ,

[0045] Where δ is the clearance between the male and female threads, and φ is the thread taper.

[0046] The original standard rotary shoulder thread structure, without weakening the male shoulder, uses a tapered fit. As torque is applied, the tapered surface continues to rise, leading to expansion of the female thread and compression of the male thread. Although this difference is not significant, it still causes the male and female threads to press against each other, resulting in an interference fit between the male and female major diameters. This makes the thread profile prone to damage. While standard rotary shoulder structures are easily repaired after thread damage without affecting other structures, the logging-while-drilling instrument's sleeve-type electronic cabin structure 100 has undergone significant modifications compared to the original rotary shoulder structure, incorporating more detailed functional structures. Repairing these structures would impact other functionalities and be very costly. To avoid interference fits and further improve structural reliability, a compensation value B needs to be designed.

[0047] Furthermore, this invention also proposes a strength verification method for the sleeve-type electronic cabin structure of a logging-while-drilling instrument, comprising the following steps: Step S1, calculating and determining the length L of the sleeve 6, where L = L0 + A + B, where L0 is the distance between the male shoulder of the drill collar male head 1 and the female shoulder of the drill collar female head 2 when the drill collar female head 2 is connected to the drill collar male head 1 and the sleeve 6 is not installed, A is the sleeve length compensation value under the action of the thread axial force F, and B is the sleeve length compensation value caused by the thread fit clearance; Step S2, establishing an assembly model of the sleeve-type electronic cabin structure 100 of the logging-while-drilling instrument based on the length L0 of the sleeve 6, and applying working condition parameters to the assembly model to simulate the real working environment of the assembly model. The working condition parameters include: the preset working parameters of the assembly model and the boundary condition parameters set for the assembly model; Step S3, obtaining the equivalent stress distribution diagram of the assembly model to determine whether the sleeve-type electronic cabin structure of the logging-while-drilling instrument meets the strength requirements.

[0048] According to the present invention, in step S1, the sleeve length compensation value A under the action of the thread axial force F and the sleeve length compensation value B caused by the thread fit clearance can be obtained by the aforementioned method.

[0049] According to the present invention, in step S2, the preset working parameters of the assembly model may include: the working torque N of the logging-while-drilling instrument during drilling, the dogleg degree M, the rated tightening torque T of the thread, the length C of the sleeve-type electronic cabin structure of the logging-while-drilling instrument, and the loading angle E.

[0050] Furthermore, the formula for calculating the loading angle E is:

[0051]

[0052] According to the present invention, in step S2, as Figure 8 As shown, the boundary condition parameters set for the assembly model may include: setting boundary condition one for one end face 101 of the logging-while-drilling instrument sleeve-type electronic cabin structure 100: the movement in the X, Y, and Z directions is set to 0, the rotation in the X and Y directions is set to 0, and the rotation angle in the Z direction is set to E; setting boundary condition two for the other end face 102 of the logging-while-drilling instrument sleeve-type electronic cabin structure 100: the rotation in the Z direction is set to E, the other degrees of freedom are released, and the torque in the X direction is N; the contact between each part is set according to the actual relationship, wherein the sleeve end face and the drill collar nut end face are set with an interference offset, the value of which is A+B.

[0053] In step S3, the assembly model with preset working parameters and boundary condition parameters is meshed, and the results can be obtained by solving the problem using ANSYS. Figure 9 The equivalent stress distribution diagram of the assembly model shown.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A sleeve-type electronic compartment structure for logging-while-drilling instruments, characterized in that, include: The drill collar comprises a male drill collar, a female drill collar threadedly connected to the male drill collar, and a sleeve fitted onto the male drill collar and located between the male shoulder of the male drill collar and the female shoulder of the female drill collar, wherein the length of the sleeve is L = L0 + A + B, where L0 is the distance between the male shoulder and the female shoulder when the female drill collar is connected to the male drill collar and the sleeve is not installed, A is the sleeve length compensation value under the action of the threaded axial force F, and B is the sleeve length compensation value caused by the thread fit clearance. Wherein, the sleeve length compensation value A under the action of the thread axial force F is the sum of the value of the sleeve being compressed and shortened by the thread axial force F and the value of the drill collar male being stretched; the calculation formula for the sleeve length compensation value B caused by the thread fit clearance is: B = δ × φ Where δ is the clearance between the male and female threads, and φ is the thread taper.

2. The sleeve-type electronic cabin structure for logging-while-drilling instruments according to claim 1, characterized in that, The formula for calculating the axial force F of the thread is: Where θ is half of the tooth angle, P is the pitch, f is the coefficient of friction, and R... t Rs is half the thread pitch diameter at 1 / 2 of the thread engagement length, Rs is half the center diameter of the shoulder contact ring, and T is the torque applied to the thread.

3. The sleeve-type electronic cabin structure for logging-while-drilling instruments according to claim 2, characterized in that, The sleeve length compensation value A under the action of the thread axial force F is obtained through finite element analysis: the thread axial force F is applied to the end face of the drill collar and the end face of the sleeve respectively, and the displacement values ​​of the two end faces are obtained respectively. The sleeve length compensation value A under the action of the thread axial force F is the sum of the absolute values ​​of the average values ​​of the two end face displacement values.

4. A method for strength verification of a sleeve-type electronic cabin structure for logging-while-drilling instruments, characterized in that, Includes the following steps: Step S1: Calculate and determine the length L of the sleeve, where L = L0 + A + B, where L0 is the distance between the male shoulder of the drill collar and the female shoulder of the drill collar when the drill collar female and male are connected and the sleeve is not installed, A is the sleeve length compensation value under the action of the thread axial force F, and B is the sleeve length compensation value caused by the thread fit clearance. The sleeve length compensation value A under the action of the thread axial force F is the sum of the value by which the thread axial force F causes the sleeve to compress and shorten and the value by which the drill collar male is stretched. The formula for calculating the sleeve length compensation value B caused by the thread fit clearance is: B = δ × φ Where δ is the clearance between the male and female threads, and φ is the thread taper; Step S2: Based on the length L0 of the sleeve, establish an assembly model of the sleeve-type electronic cabin structure of the logging-while-drilling instrument, and apply working condition parameters to the assembly model to simulate the real working environment of the assembly model. The working condition parameters include: preset working parameters of the assembly model and boundary condition parameters set for the assembly model. Step S3: Obtain the equivalent stress distribution diagram of the assembly model to determine whether the sleeve-type electronic cabin structure of the logging-while-drilling instrument meets the strength requirements.

5. The strength verification method for the sleeve-type electronic cabin structure of the logging-while-drilling instrument according to claim 4, characterized in that, In step S1, the sleeve length compensation value A under the action of the thread axial force F is obtained by finite element analysis: the thread axial force F is applied to the drill collar end face and the sleeve end face respectively, and the displacement values ​​of the two end faces are obtained. The compensation value A is the sum of the absolute values ​​of the average values ​​of the two end face displacement values.

6. The strength verification method for the sleeve-type electronic cabin structure of the logging-while-drilling instrument according to claim 4, characterized in that, In step S2, the preset working parameters of the assembly model include: the working torque N of the logging-while-drilling instrument during drilling, the dogleg degree M, the rated tightening torque T of the thread, the length C of the sleeve-type electronic cabin structure of the logging-while-drilling instrument, and the loading angle E.

7. The strength verification method for the sleeve-type electronic compartment structure of the logging-while-drilling instrument according to claim 6, characterized in that, The formula for calculating the loading angle E is: 。 8. The strength verification method for the sleeve-type electronic cabin structure of the logging-while-drilling instrument according to claim 6, characterized in that, In step S2, the boundary condition parameters set for the assembly model include: setting boundary condition one for one end face of the logging-while-drilling instrument sleeve-type electronic cabin structure: the movement in the X, Y, and Z directions is set to 0, the rotation in the X and Y directions is set to 0, and the rotation angle in the Z direction is set to E; setting boundary condition two for the other end face of the logging-while-drilling instrument sleeve-type electronic cabin structure: the rotation in the Z direction is set to E, the remaining degrees of freedom are released, and the torque in the X direction is N; the contact between each part is set according to the actual relationship, wherein the sleeve end face and the drill collar nut end face are set with an interference offset, the value of which is A+B.

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