Composite frictional wear test piece, experimental device and simulation method

Abstract

The invention provides a composite frictional wear test piece, which comprises a driving mechanism used for being connected with a connecting shaft, the driving mechanism comprises a first connecting piece, a plurality of grooves arranged at the lower end surface of the first connecting piece at intervals along the circumferential direction, and a fastening mechanism arranged below the driving mechanism, and the friction mechanism is arranged between the driving mechanism and the fastening mechanism and comprises an annular friction part and a locking part, and the locking part is arranged on the upper end face of the friction part and used for being matched with the groove. By reasonably setting test parameters and a use method, the friction mechanism in the composite friction and wear test piece can be always in contact with the friction medium for friction and wear.

Description

Technical Field

[0001] The present invention relates to the technical field of safety in oil and gas resource development, and particularly to a composite friction and wear specimen, an experimental device and a simulation method. Background Art

[0002] Wear is a major cause leading to the failure of drill pipes and casings during the drilling process. The wear of drill pipes and casings is mainly caused by the contact between the rotating drill pipe and the casing under the conditions of bending deformation or high dogleg severity of the wellbore trajectory.

[0003] With the continuous exploration and exploitation of oil and gas moving deeper into unconventional environments such as ultra-deep wells, "high temperature, high pressure, high corrosion" working conditions, large displacement, multi-fishbone horizontal wells and offshore development, higher requirements are put forward for the performance of oil pipes. At present, the average exploitation depth of the main development blocks is 6800 m. Especially for high-yield gas fields, their high-quality integral reserves reach 1000×10^8 m 3 , the bottom hole pressure is close to 140 MPa, the completion depth exceeds 8000 m, and the exploration and development are extremely difficult. Under such ultra-deep, high-pressure and high-temperature working conditions, conventional steel drill strings not only bear extremely large loads, but also have to withstand complex loads such as internal pressure / external pressure, tension / compression, wear, rotational fatigue, bending, and temperature difference stress in the wellbore, resulting in long drilling cycles, frequent accidents and high costs in ultra-deep well drilling. During the drilling process of deep wells and ultra-deep wells, due to the intense friction and collision between the drill pipe and the outer layer of formation rocks and steel pipes during high-speed drilling in the wellbore, and the friction and wear process is more complex and harsh under the medium conditions of drilling fluid, it poses a great challenge to the wear resistance and service life of drill pipes / casings.

[0004] CN105891036B discloses a punching-sliding composite friction and wear test device and its method: clamping a spherical upper specimen on an upper fixture, and clamping a planar lower specimen with a lower fixture; controlling the up and down movement of the lower fixture through a precision screw lifting table to make the upper and lower specimens contact; the servo motor drives the upper specimen to perform reciprocating up and down movement at a set frequency f, number of times N and displacement S in turn through an eccentric disc, an upper joint bearing, a lower joint bearing, an impact shaft, a spring plate and an upper fixture, and reciprocatingly impacts the lower specimen; during the impact process, the spring plate is deformed by force, thereby realizing the punching-sliding composite friction and wear between the upper and lower specimens; at the same time, a three-dimensional dynamic piezoelectric sensor connected to the lower fixture measures the force borne by the lower specimen and sends it to the data acquisition and control system to analyze and obtain the friction coefficient and cycle number curve. The specimen of this device is spherical and can only achieve axial reciprocating friction and wear, and does not have the simulation conditions for rotational friction and wear.

[0005] CN110411882B discloses a multi-condition simulation tube inner wall friction and wear test device, including a test base, a rotating frame and a tube to be tested. Inside the tube to be tested, there is a stirrer for rotating and stirring a solution to simulate sand particle wear on the inner wall of the tube. Inside the tube to be tested, there is a hollow force-applying lever. At the bottom end of the force-applying lever, there is a bearing steel ball that fits and contacts the inner wall of the tube to be tested. Between the force-applying lever and the outer wall of the tube to be tested, there is a voltage sensor that monitors the resistance voltage division of the inner wall film layer of the tube to be tested and real-time characterizes the wear condition of the inner wall film layer of the tube to be tested through voltage signals. Gas that can enter near the friction interface to simulate the bubble disturbance effect during the friction and wear process is introduced into the inner hole of the force-applying lever. This device can realize the friction and wear test of the tube inner wall under conventional conditions, but it does not have the simulation conditions to achieve uniform friction on the entire surface of the specimen.

[0006] Therefore, in the art, there is a desire to provide a composite friction and wear specimen to solve the above technical problems. Summary of the Invention

[0007] The object of the present invention is to provide a composite friction and wear specimen, which can ensure that the friction mechanism in the composite friction and wear specimen can always contact the friction medium and perform friction and wear by reasonably setting test parameters and usage methods, realizing uniform friction throughout the entire process of the target, and further eliminating the situation of the friction halving area. In addition, an experimental device and a simulation method are also provided.

[0008] According to a first aspect of the present invention, there is provided a composite friction and wear specimen, including a driving mechanism for connecting with a connecting shaft. The driving mechanism includes a first connecting member, and a plurality of grooves arranged at intervals in the circumferential direction on the lower end surface of the first connecting member.

[0009] A fastening mechanism arranged below the driving mechanism, and

[0010] A friction mechanism arranged between the driving mechanism and the fastening mechanism, which includes a friction part configured in an annular form, and a locking part arranged on the upper end surface of the friction part and adapted to the groove.

[0011] In one embodiment, the first connecting member is configured in a cylindrical form. The fastening mechanism includes a fastener configured in a columnar form, and a locking member extending axially upward along the fastener.

[0012] Wherein, the locking member is configured to be able to extend into the first connecting member, so that a sealed connection is formed between the friction part and both the first connecting member and the fastener.

[0013] In one embodiment, the driving mechanism further includes a second connecting member extending axially upward along the first connecting member, and the driving mechanism is configured to form a threaded connection with the connecting shaft through the second connecting member.

[0014] In one embodiment, a stepped surface that extends radially inward and is used to abut against the connecting shaft is formed at the joint of the first connecting member and the second connecting member.

[0015] In one embodiment, the outer diameters of the first connecting member, the friction portion, and the fastener are all equal.

[0016] In one embodiment, the outer diameter of the friction portion is in the range of 20 mm to 30 mm.

[0017] In one embodiment, the composite friction and wear specimen includes through holes provided on the first connecting member and the fastener, and an iron rod that is adapted to the through holes and is rotationally fastened.

[0018] According to a second aspect of the present invention, there is provided an experimental device for simulating oil and gas drilling and production conditions, including the composite friction and wear specimen as described above, a connecting shaft for forming a threaded connection with the composite friction and wear specimen, and a friction medium for clamping the composite friction and wear specimen, wherein an inner peripheral surface of the friction medium forms a sealed connection with an outer peripheral surface of the composite friction and wear specimen.

[0019] In one embodiment, the connecting shaft includes a first connecting shaft portion connected to the composite friction and wear specimen, a second connecting shaft portion connected to an external driving mechanism, and a third connecting shaft portion provided between the first connecting shaft portion and the second connecting shaft portion, wherein an outer diameter of the third connecting shaft portion gradually increases in a direction from the first connecting shaft portion to the second connecting shaft portion.

[0020] In one embodiment, the external driving mechanism includes an axially reciprocating device and a rotator, and an installation portion that extends radially outward and is used to axially abut against the rotator is provided on the second connecting shaft portion.

[0021] The connecting shaft further includes a plurality of card slot portions that are circumferentially spaced apart on the second connecting shaft portion and are adapted to the rotator, and a joint portion that is provided above the card slot portions and is used to form a threaded connection with the axially reciprocating device, wherein the card slot portions are above the installation portion.

[0022] According to a third aspect of the present invention, there is provided a method for simulating oil and gas drilling and production conditions by using the experimental device as described above, including the following steps:

[0023] S1. The connecting shaft is connected to the composite friction and wear specimen; the composite friction and wear specimen is clamped by the friction medium;

[0024] S2. Set various experimental parameters; the connecting shaft is used to cause the composite friction and wear specimen to perform friction and wear in different ways within the height range of the friction medium;

[0025] S3. Remove the friction mechanism in the composite friction and wear specimen, clean, dry and weigh it to determine the friction weight loss; obtain the microscopic friction and wear morphology data by cutting the friction mechanism.

[0026] In one embodiment, the friction and wear modes in step S2 include axial reciprocating motion and / or rotational motion.

[0027] Compared with the prior art, the advantages of the present invention are as follows:

[0028] Firstly, the present invention can achieve various friction and wear motion forms for the complex working conditions of oil and gas drilling and production. For example, perform axial reciprocating motion alone, rotational motion alone, and composite motion (i.e., perform axial reciprocating motion and rotational motion simultaneously). And, by reasonably setting the test parameters and usage methods, it is ensured that the friction mechanism in the composite friction and wear specimen can always be in contact with the friction medium and perform friction and wear, realizing uniform friction throughout the whole process of the target, and further eliminating the situation of the friction half region.

[0029] Secondly, the composite friction and wear specimen in the present invention is constructed as a split specimen, that is, it consists of three sequentially connected parts (driving mechanism, fastening mechanism, and friction mechanism). Compared with the prior art, it can not only reduce the mass and volume of the specimen to be measured, but also improve the fault tolerance rate of the experiment.

[0030] In addition, due to the fact that during composite friction (axial reciprocating motion and / or rotational motion), the composite friction and wear specimen can be in full contact with the friction medium and perform reciprocating relative motion to ensure that the entire surface of the composite friction and wear specimen can achieve uniform and sufficient friction. Therefore, when measuring the friction and wear quality of the composite friction and wear specimen, it is only necessary to directly measure the friction mechanism. In this way, not only the mass and volume of the specimen to be measured are effectively reduced, but also the measurement accuracy of the friction and wear quality of the specimen is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be described in detail below with reference to the drawings. In the drawings:

[0032] Figure 1 Schematically shows the structure of the composite friction and wear specimen according to the present invention;

[0033] Figure 1aCross-sectional view of the composite friction and wear specimen according to the present invention;

[0034] Figure 2 Cross-sectional view of the driving mechanism in the composite friction and wear specimen according to the present invention;

[0035] Figure 3 Cross-sectional view of the friction mechanism in the composite friction and wear specimen according to the present invention;

[0036] Figure 3a is Figure 3 Cross-sectional view taken along line A-A in

[0037] Figure 4 Cross-sectional view of the fastening mechanism in the composite friction and wear specimen according to the present invention;

[0038] Figure 5 Schematically shows the structure of the connecting shaft in the experimental device according to the present invention;

[0039] Figure 5a is Figure 5 Cross-sectional view taken along line C-C in

[0040] Figure 6 Top view of the friction medium in the experimental device according to the present invention;

[0041] Figure 7 Schematically shows the first friction state of the experimental device according to the present invention;

[0042] Figure 8 Schematically shows the second friction state of the experimental device according to the present invention.

[0043] In the drawings, like parts are designated by like reference numerals. The drawings are not drawn to actual scale.

[0044] The meanings of the reference numerals in the drawings are as follows:

[0045] 10 driving mechanism, 11 first connecting member, 111 stepped surface, 12 groove, 13 second connecting member,

[0046] 20 fastening mechanism, 21 fastener, 22 locking member,

[0047] 30 friction mechanism, 31 friction portion, 32 locking portion,

[0048] 41 first through hole, 42 second through hole,

[0049] 100 composite friction and wear specimen,

[0050] 200 connecting shaft, 201 friction medium,

[0051] 210 First connecting shaft portion, 220 second connecting shaft portion, 221 mounting portion, 222 card slot portion, 223 engaging portion, 230 third connecting shaft portion. Detailed implementation

[0052] In order to make the technical solutions and advantages of the present invention clearer and more understandable, the exemplary embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than an exhaustive list of all embodiments. And without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0053] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of these features.

[0054] In the present invention, unless otherwise clearly defined and limited, the terms "mounting", "connecting", "coupling", "fixing", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements.

[0055] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] The present invention will be further described below with reference to the accompanying drawings.

[0057] Figure 1 Schematically shows the structure of the composite friction and wear specimen according to the present invention;

[0058] Figure 1a Is a cross-sectional view of the composite friction and wear specimen according to the present invention;

[0059] Figure 2 Is a cross-sectional view of the driving mechanism in the composite friction and wear specimen according to the present invention;

[0060] Figure 3 Is a cross-sectional view of the friction mechanism in the composite friction and wear specimen according to the present invention;

[0061] Figure 3a Is Figure 3 The sectional view at A-A in

[0062] Figure 4 Is a cross-sectional view of the fastening mechanism in the composite friction and wear specimen according to the present invention;

[0063] Figure 5 Schematically shows the structure of the connecting shaft in the experimental device according to the present invention;

[0064] Figure 5a is Figure 5 a cross-sectional view taken at C-C in;

[0065] Figure 6 is a top view of the friction medium in the experimental device according to the present invention;

[0066] Figure 7 Schematically shows the first friction state of the experimental device according to the present invention;

[0067] Figure 8 Schematically shows the second friction state of the experimental device according to the present invention.

[0068] As Figure 1 、 1a and shown in 2, according to the first aspect of the present invention, there is provided a composite friction and wear specimen 100, which includes a driving mechanism 10 for forming a threaded connection with a connecting shaft 200. The driving mechanism 10 includes a first connecting member 11 configured in a cylindrical form, and a plurality of grooves 12 arranged at intervals in the circumferential direction at the lower end surface of the first connecting member 11.

[0069] In one embodiment, as Figure 1 、 1a and shown in 4, the composite friction and wear specimen 100 further includes a fastening mechanism 20 provided below the driving mechanism 10, and a friction mechanism 30 provided between the driving mechanism 10 and the fastening mechanism 20. Preferably, the friction mechanism 30 is configured to be able to maintain a stable posture under the action of the driving mechanism 10 and the fastening mechanism 20 to achieve the purpose of comprehensive and uniform friction.

[0070] According to the present invention, as Figure 1 、 1a 、3, 3a and shown in 4, the friction mechanism 30 includes a friction portion 31 configured in a ring form, and a locking portion 32 provided on the upper end surface of the friction portion 31. Among them, the locking portion 32 in the friction mechanism 30 can be nested in the groove 12 in the driving mechanism 10 so that the locking portion 32 and the groove 12 form a tight connection relationship.

[0071] When the friction mechanism 30 is docked with the driving mechanism 10, the locking portion 32 in the friction mechanism 30 can be adapted to the groove 12 in the driving mechanism 10, so as to promote a sealed connection relationship to be formed between the lower end surface of the first connecting member 11 and the upper end surface of the friction portion 31, further improving the stability of the friction portion 31 during the simulated friction process.

[0072] It is easy to understand that the cooperation relationship between the groove 12 in the driving mechanism 10 and the locking portion 32 in the friction mechanism 30 can effectively avoid the occurrence of frictional slip under large frictional forces, thereby ensuring that the friction mechanism 30 can be subjected to uniform and comprehensive friction.

[0073] In one embodiment, as Figure 4 shown, the fastening mechanism 20 includes a fastener 21 configured in the form of a cylinder, and a locking member 22 extending axially upward along the fastener 21. Among them, the outer diameter of the locking member 22 is smaller than the outer diameter of the fastener 21, and the fastening mechanism 20 is configured to be able to extend into the first connecting member 11 and form a threaded connection with the first connecting member 11 through the locking member 22 to improve the overall firmness of the composite friction and wear specimen 100.

[0074] In addition, by strengthening the connection relationship between the fastening mechanism 20 and the driving mechanism 10, it is possible to promote better sealing between the friction mechanism 30, the fastening mechanism 20, and the driving mechanism 10. Further, a sealed connection can be formed between the upper end surface of the friction portion 31 and the lower end surface of the first connecting member 11, and between the lower end surface of the friction portion 31 and the upper end surface of the fastener 21.

[0075] In this way, the friction mechanism 30 can always be located between the fastening mechanism 20 and the driving mechanism 10 during the simulated friction process to obtain a stable working environment.

[0076] In one embodiment, as Figure 2 shown, the driving mechanism 10 further includes a second connecting member 13 extending axially upward along the first connecting member 11. Preferably, the outer diameter of the second connecting member 13 is smaller than the outer diameter of the first connecting member 11, and the driving mechanism 10 is configured to be able to form a threaded connection with the connecting shaft 200 through the second connecting member 13, thereby improving the firmness between the composite friction and wear specimen 100 and the connecting shaft 200. In this way, the composite friction and wear specimen 100 and the connecting shaft 200 can achieve synchronous movement.

[0077] In one embodiment, as Figure 2 shown, a stepped surface 111 extending radially inward and used for abutting against the connecting shaft 200 is formed at the joint of the first connecting member 11 and the second connecting member 13. It is easy to understand that the connecting shaft 200 is sleeved outside the second connecting member 13 and can axially abut against the stepped surface 111 to further improve the firmness between the composite friction and wear specimen 100 and the connecting shaft 200.

[0078] In one embodiment, the outer diameters of the first connecting member 11, the friction portion 31, and the fastener 21 are all equal. In this way, when the composite friction and wear specimen 100 undergoes composite friction (axial reciprocating motion and / or rotational motion) in the friction medium 201 (introduced below), the composite friction and wear specimen 100 can be in full contact with the friction medium 201 and perform reciprocating relative motion to ensure that the entire surface of the composite friction and wear specimen 100 can achieve uniform and sufficient friction.

[0079] In one embodiment, the outer diameter of the friction portion 31 is in the range of 20 mm to 30 mm. It is easy to understand that the friction mechanism 30 in the present invention is the core part that bears friction and wear and conducts analysis and characterization.

[0080] According to the present invention, the composite friction and wear specimen 100 further includes through holes provided on the first connecting member 11 and the fastener 21, and an iron rod that is adapted to the through holes and is rotationally fastened.

[0081] Preferably, as Figure 1 and 1a shown, the through holes include a first through hole 41 on the first connecting member 11 and a second through hole 42 on the fastener 21; the iron rod includes a first iron rod for being installed in the first through hole 41 and a second iron rod for being installed in the second through hole 42.

[0082] It is easy to understand that by inserting the second iron rod into the second through hole 42 on the fastener 21, the driving mechanism 10 and the fastening mechanism 20 can be rotationally fastened by rotating the second iron rod, and then the driving mechanism 10 and the fastening mechanism 20 can be fixedly connected, so as to ensure the synchronous movement of the driving mechanism 10, the fastening mechanism 20, and the friction mechanism 30; by inserting the first iron rod into the first through hole 41 on the first connecting member 11, the connecting shaft 200 and the composite friction and wear specimen 100 can be rotationally fastened by rotating the first iron rod, and then the driving mechanism 10 and the fastening mechanism 20 can be fixedly connected, so as to ensure the synchronous movement of the connecting shaft 200 and the composite friction and wear specimen 100.

[0083] It is easy to understand that since the locking portion 32 in the friction mechanism 30 is nested in the groove 12 in the driving mechanism 10, the friction mechanism 30 and the driving mechanism 10 can move synchronously, which has been specifically introduced above and will not be elaborated here.

[0084] Compared with the prior art, the composite friction and wear specimen 100 in the present invention is constructed as a split specimen, that is, it is composed of three sequentially connected parts (the driving mechanism 10, the fastening mechanism 20, and the friction mechanism 30). In this way, not only can the mass and volume of the specimen to be measured be reduced, but also the error tolerance rate of the experiment can be improved.

[0085] In addition, during compound friction (axial reciprocating motion and / or rotational motion), the compound friction and wear specimen 100 can come into sufficient contact with the friction medium 201 and perform reciprocating relative motion to ensure that the entire surface of the compound friction and wear specimen 100 can achieve uniform and sufficient friction. Therefore, when measuring the friction and wear quality of the compound friction and wear specimen 100, it is only necessary to directly measure the friction mechanism 30. In this way, not only is the mass and volume of the specimen to be measured effectively reduced, but also the measurement accuracy of the friction and wear quality of the specimen is improved.

[0086] According to the second aspect of the present invention, as Figure 1 、 5 shown in FIG. 6, an experimental device for simulating oil and gas drilling and production conditions is provided, including the compound friction and wear specimen 100 as described above, a connecting shaft 200 for forming a threaded connection with the compound friction and wear specimen 100, and a friction medium 201 for clamping the compound friction and wear specimen.

[0087] In an embodiment of the present invention, as Figure 7 and 8 shown in FIG., two friction media 201 are provided and are respectively located on both sides of the compound friction and wear specimen 100. Preferably, the inner surface of the friction medium 201 is configured as an arc surface. Therefore, during the simulation of friction, the inner peripheral surface of the friction medium 201 can form a sealed connection with the outer peripheral surface of the compound friction and wear specimen 100, thereby ensuring that the entire surface of the compound friction and wear specimen 100 can uniformly and sufficiently friction with the friction medium 201, and further improving the measurement accuracy of the friction and wear quality of the compound friction and wear specimen 100.

[0088] In a specific embodiment, the friction medium 201 is mainly made of media such as rock formations and casings that cause material friction loss. The friction medium 201 is configured as a cuboid with an overall length of 35 - 40 mm, a width of 35 mm, and a height of 60 - 100 mm, and an arc-shaped groove with a diameter consistent with the outer diameter of the friction component and a radian between 60° and 180° is provided on one side.

[0089] During the simulation experiment, the two friction media 201 are arranged oppositely on both sides of the compound friction and wear specimen 100, and the same inward loads are respectively applied. At the same time, the compound friction and wear specimen 100 performs compound friction and wear motion under the action of the connecting shaft 200.

[0090] It should be noted that assuming the friction medium 201 is placed at a height of X mm, since the thickness of the friction part 31 in the friction mechanism 30 is 10 mm, the axial reciprocating stroke (Y) ≤ ±(X - 10) mm. In this way, it can be ensured that the friction part 31 can always be in full contact with the friction medium 201 and carry out friction and wear work, while the rotation speed and reciprocating frequency need to be calculated according to the actual working conditions on site and parameters such as the axial reciprocating frequency and axial reciprocating stroke.

[0091] That is: Rotating friction speed = (π * outer diameter of the composite friction and wear specimen * rotation speed) / 60

[0092] Reciprocating friction speed = 2 * axial reciprocating stroke * axial reciprocating frequency

[0093] In one embodiment, as Figure 5 shown, the connecting shaft 200 includes a first connecting shaft portion 210 connected to the composite friction and wear specimen 100, a second connecting shaft portion 220 connected to an external driving mechanism (not shown), and a third connecting shaft portion 230 disposed between the first connecting shaft portion 210 and the second connecting shaft portion 220.

[0094] Preferably, the outer diameter of the third connecting shaft portion 230 gradually increases from the first connecting shaft portion 210 to the second connecting shaft portion 220, so as to ensure full cooperation with the size of the composite friction and wear specimen 100.

[0095] Preferably, inside the first connecting shaft portion 210 of the present invention, there is a φ20 internal thread section with a length of about 40 mm, so that it can form a threaded connection with the fastener 21 to ensure that the connecting shaft 200 can move in coordination with the composite friction and wear specimen 100.

[0096] In a specific embodiment, threads are formed on the outer wall of the fastener 21, so that it can form a threaded connection with the first connecting shaft portion 210 of the connecting shaft 200 to improve the firmness of the connecting shaft 200 and the composite friction and wear specimen 100.

[0097] In a preferred embodiment, the external driving mechanism includes an axial reciprocator (not shown) and a rotator (not shown). Among them, the axial reciprocator can drive the connecting shaft 200 and the composite friction and wear specimen 100 to perform axial reciprocating motion; the rotator can drive the connecting shaft 200 and the composite friction and wear specimen 100 to perform rotational motion.

[0098] It is easy to understand that the composite friction and wear specimen 100 in the present invention can perform axial reciprocating motion alone, can also perform rotational motion alone, and can also complete axial reciprocating motion and rotational motion simultaneously.

[0099] In one embodiment, asFigure 5 As shown, an installation part 221 that extends radially outward and is used to axially abut against the rotator is provided on the second connecting shaft part 220, thereby providing a good supporting environment for the rotator and cooperating with the card slot part 222 (introduced below) to improve the firmness between the rotator and the connecting shaft 200.

[0100] Preferably, the size of the installation part 221 in the present invention is φ53, and the table width is about 6.5 mm.

[0101] In one embodiment, as Figure 5 and 5a shown, the connecting shaft 200 further includes a plurality of card slot parts 222 that are circumferentially spaced apart on the second connecting shaft part 220 and are used to adapt to the rotator. Thus, under the combined action of the card slot part 222 and the installation part 221, the rotator can be firmly installed on the connecting shaft 200.

[0102] Preferably, the card slot part 222 is located above the installation part 221.

[0103] In one embodiment, as Figure 6 shown, the connecting shaft 200 further includes an engaging part 223 that is provided above the card slot part 222 and is used to form a threaded connection with the axially reciprocating device. It is easy to understand that the axially reciprocating device can be firmly installed on the connecting shaft 200 through the engaging part 223, thereby helping to achieve the purpose of driving the connecting shaft 200 and the composite friction and wear test piece 100.

[0104] Preferably, the cooperation between the engaging part 223 and the card slot part 222 can firmly install the axially reciprocating device and the rotator on the connecting shaft 200, thereby avoiding the occurrence of gaps and the situation of rotation / reciprocating motion lag during the experiment.

[0105] According to the third aspect of the present invention, a method for simulating the oil and gas drilling and production working conditions by using the experimental device as described above is provided, including the following steps.

[0106] Step 1: Fix the connecting shaft 200 and the composite friction and wear test piece 100 in a fixed connection; apply a lateral load through two friction media 201 to clamp the composite friction and wear test piece 100;

[0107] Step 2: Set various experimental parameters; make the composite friction and wear test piece perform different types of friction and wear within the height range of the friction medium 201 through the connecting shaft 200.

[0108] Step 3: Stop the experiment when the preset time is reached. Remove the friction mechanism 30 from the composite friction and wear specimen 100, clean, dry, and weigh it to determine the friction weight loss. Then, use a wire cutting device (not shown) to cut out the part of the friction mechanism 30 that needs to observe the microtopography, and then use a scanning electron microscope (not shown) to observe the microtopography and obtain relevant data.

[0109] It should be noted that the main research objectives are selected according to the drilling construction stage, operation area, and reservoir properties. The main research objectives mainly include friction and wear components (drill pipes, casings, etc.), friction and wear target materials (metal materials determined according to oil pipes), friction and wear block materials (metals, rocks, etc.), and friction and wear methods (rotary friction, reciprocating friction, composite friction).

[0110] In Step 1, adjust the axial position of the composite friction and wear specimen 100 through the connecting shaft 200 so that the upper end face of the friction medium 201 is flush with the upper end face of the friction mechanism 30 or the lower end face of the friction medium 201 is flush with the lower end face of the friction mechanism 30.

[0111] The main experimental parameters in Step 2 mainly include the outer diameter of the composite friction and wear specimen (20 - 30 mm), rotational speed (5 - 250 r / min), axial reciprocating speed (0.02 - 1.0 m / s), axial reciprocating stroke (0 - ±50 mm), axial reciprocating frequency (2 - 15 Hz), lateral load (0.1 - 10 KN), height of the friction and wear block (60 - 100 mm), and arc of the groove of the friction and wear block (60 - 180°).

[0112] In Step 2, it should be noted that assuming the height of the friction medium 201 placed is X mm, since the thickness of the friction part 31 in the friction mechanism 30 is 10 mm, the axial reciprocating stroke (Y) ≤ ±(X - 10) mm. In this way, it can be ensured that the friction part 31 can always be in full contact with the friction medium 201 and perform friction and wear work, while the rotational speed and reciprocating frequency need to be calculated according to the actual on-site working conditions and parameters such as the axial reciprocating frequency and axial reciprocating stroke.

[0113] That is: Rotary friction speed = (π * outer diameter of the composite friction and wear specimen * rotational speed) / 60

[0114] Reciprocating friction speed = 2 * axial reciprocating stroke * axial reciprocating frequency

[0115] In Step 3, a ultrasonic cleaning machine (not shown) is needed to clean the friction part 31 in the friction mechanism 30 and then dry it. Subsequently, use a balance with an accuracy of one ten-thousandth (not shown) to weigh the friction mechanism 30, and take the average of 3 times.

[0116] In Step 2, different friction modes include performing axial reciprocating motion alone, performing rotational motion alone, and compound motion (i.e., performing axial reciprocating motion and rotational motion simultaneously).

[0117] In Step 3, it is necessary to cut the friction mechanism 30 and obtain its microscopic friction and wear morphology data through SEM. (SEM in the present invention is a scanning electron microscope)

[0118] The assembly process of the relevant experimental device is briefly described below.

[0119] First, the driving mechanism 10, the fastening mechanism 20, and the friction mechanism 30 are fixedly connected by threads and slots (the locking portion 32 in the friction mechanism 30 and the groove 12 in the driving mechanism 10).

[0120] Then, the second iron rod is inserted into the second through hole 42 on the fastener 21 to achieve rotational fastening.

[0121] Finally, the assembled composite friction and wear specimen 100 is fixedly connected to the connecting shaft 200 by threads, and the first iron rod is inserted into the first through hole 41 on the first connecting member 11 to achieve rotational fastening.

[0122] The first embodiment of the present invention is introduced below: During the drilling process, the drill pipe (composite friction and wear specimen 100) is eccentrically worn with the casing.

[0123] During the drilling process, due to the drill pipe being prone to bending deformation when drilling downward under the formation resistance, and coming into contact with the upper casing to cause friction and wear, resulting in the failure of the drill pipe / casing. The friction and wear form is a composite friction mode combining reciprocating friction and rotational friction.

[0124] S1: Select the main research objectives according to the drilling construction stage, operation area, and reservoir properties:

[0125] (1) Composite friction and wear specimen 100: Drill pipe, made of G105 steel;

[0126] (2) Friction medium 201: Casing, made of P110 steel;

[0127] (3) Friction and wear mode: Composite friction (performing axial reciprocating motion and rotational motion simultaneously).

[0128] S2: Define the friction and wear experiment parameters according to the research requirements

[0129] (1) Outer diameter of the composite friction and wear specimen 100: 20 mm;

[0130] (2) Rotational speed: 20 r / min;

[0131] (3) Axial reciprocating speed: 0.5 m / s;

[0132] (4) Axial reciprocating stroke: 50 mm;

[0133] (5) Axial reciprocating frequency: 10 Hz;

[0134] (6) Lateral load: 50 KN;

[0135] (7) Height of friction medium 201: 60 mm;

[0136] (8) Groove radian of friction medium 201: 60°

[0137] S3: After cleaning and drying the friction mechanism 30 in the composite friction and wear specimen 100 using an ultrasonic cleaner, weigh the friction assembly using a balance with a precision of one ten-thousandth, and take the average of three measurements;

[0138] S4: Install the experimental device

[0139] (1) Connect the three parts (drive mechanism 10, fastening mechanism 20, friction mechanism 30) of the composite friction and wear specimen 100 through threads and slots, and use an iron rod to insert into the through holes reserved on the drive mechanism 10 and the fastening mechanism 20 for fastening;

[0140] (2) Connect the composite friction and wear specimen 100 and the connecting shaft 200 through threads, and use an iron rod to insert into the through hole reserved on the drive mechanism 10 for fastening;

[0141] (3) Install two corresponding friction media 201 at the designated positions on the friction and wear testing machine (experimental device) and fix them;

[0142] (4) Adjust the reciprocating motion mechanism of the friction and wear testing machine to make the upper end of the friction mechanism 30 in the composite friction and wear specimen 100 level with the friction medium 201;

[0143] (5) Set the pressure loads on both sides of the friction medium 201 according to the experimental requirements and apply them to the target value to make the two friction media 201 tightly clamp the composite friction and wear specimen 100, and then put the composite friction and wear specimen 100 and the friction medium 201 into the drilling fluid;

[0144] S5: Set the operating values of the friction and wear testing machine according to the experimental parameters determined in S2;

[0145] S6: Start the experiment, make the friction mechanism 30 always within the height range of the friction medium 201, contact the friction medium 201 and conduct friction and wear;

[0146] S7: When it reaches 300 min, stop the experiment, remove the friction mechanism 30 from the composite friction and wear specimen 100, clean, dry, and weigh it to determine the friction weight loss; then, use a wire cutting device (not shown) to cut out the part of the friction mechanism 30 that needs to observe the microscopic morphology, and then use a scanning electron microscope (not shown) to observe the microscopic morphology and obtain relevant data.

[0147] S8: The experiment ends.

[0148] The second embodiment of the present invention is introduced below: During the process of casing running, the casing (composite friction and wear specimen 100) undergoes friction and wear with the formation.

[0149] During the process of casing running, the casing rotates and is lowered in the wellbore following the crown block. Due to the uneven surface of the wellbore, the casing undergoes friction and wear during the lowering process, and the friction and wear form is a composite friction mode combining reciprocating friction and rotational friction.

[0150] S1: Select the main research objectives according to the drilling construction stage, operation area, and reservoir properties:

[0151] (1) Composite friction and wear specimen 100: Casing, the material is N80 steel;

[0152] (2) Friction medium 201: Rock;

[0153] (3) Friction and wear mode: Composite friction (axial reciprocating motion and rotational motion are carried out simultaneously).

[0154] S2: Define the friction and wear experiment parameters according to the research requirements

[0155] (1) The outer diameter of the composite friction and wear specimen 100 is 30 mm;

[0156] (2) Rotational speed: 50 r / min;

[0157] (3) Axial reciprocating speed: 0.6 m / s;

[0158] (4) Axial reciprocating stroke: 60 mm;

[0159] (5) Axial reciprocating frequency: 10 Hz;

[0160] (6) Lateral load: 50 KN;

[0161] (7) The height of the friction medium 201: 70 mm;

[0162] (8) The groove radian of the friction medium 201: 90°;

[0163] S3: After cleaning and drying the friction mechanism 30 in the composite friction and wear specimen 100 using an ultrasonic cleaner, weigh the friction mechanism 30 using a balance with a precision of one ten-thousandth, and take the average value of three measurements.

[0164] S4: Install the experimental device.

[0165] (1) Connect the three parts (driving mechanism 10, fastening mechanism 20, friction mechanism 30) of the composite friction and wear specimen 100 through threads and slots, and use an iron rod to extend into the through holes reserved on the driving mechanism 10 and the fastening mechanism 20 for fastening.

[0166] (2) Connect the composite friction and wear specimen 100 to the connecting shaft 200 through threads, and use an iron rod to extend into the through hole reserved on the driving mechanism 10 for fastening.

[0167] (3) Install two corresponding friction media 201 at the designated positions on the friction and wear testing machine (experimental device) and fix them.

[0168] (4) Adjust the reciprocating motion mechanism of the friction and wear testing machine so that the upper end of the friction mechanism 30 in the composite friction and wear specimen 100 is flush with the friction medium 201.

[0169] (5) Set the pressure loads on both sides of the friction medium 201 according to the experimental requirements and apply them to the target value so that the two friction media 201 tightly clamp the composite friction and wear specimen 100. Then, place the composite friction and wear specimen 100 and the friction medium 201 into the drilling fluid.

[0170] S5: Set the operating values of the friction and wear testing machine according to the experimental parameters determined in S2.

[0171] S6: Start the experiment, so that the friction mechanism 30 is always within the height range of the friction medium 201, contact the friction medium 201 and carry out friction and wear.

[0172] S7: When it reaches 300 minutes, stop the experiment, remove the friction mechanism 30 in the composite friction and wear specimen 100, clean, dry, and weigh it to determine the friction weight loss. Then, use a wire cutting device (not shown) to cut out the part of the friction mechanism 30 that needs to observe the microscopic morphology, and then use a scanning electron microscope (not shown) to observe the microscopic morphology and obtain relevant data.

[0173] S8: The experiment ends.

[0174] The following introduces the third embodiment of the present invention: The friction and wear between the drill pipe (composite friction and wear specimen 100) and the casing during the process of tripping in and out of the drill pipe.

[0175] During the process of tripping in and out the drill pipe, due to the drill pipe process, it bends under the action of force and contacts the casing, and friction and wear occur with the casing during the process of being lifted, and the form of friction and wear is reciprocating friction.

[0176] S1: Select the main research objectives according to the drilling construction stage, operation area, and reservoir properties:

[0177] (1) Composite friction and wear specimen 100: drill pipe, with the material being E75 steel;

[0178] (2) Friction medium 201: casing, with the material being TP140 steel;

[0179] (3) Friction and wear mode: reciprocating friction (axial reciprocating motion and rotational motion are carried out simultaneously).

[0180] S2: Define the friction and wear test parameters according to the research requirements

[0181] (1) Outer diameter of the composite friction and wear specimen 100: 20 mm;

[0182] (3) Axial reciprocating speed: 0.9 m / s;

[0183] (4) Axial reciprocating stroke: 90 mm;

[0184] (5) Axial reciprocating frequency: 10 Hz;

[0185] (6) Lateral load: 30 KN;

[0186] (7) Height of the friction medium 201: 100 mm;

[0187] (8) Groove radian of the friction medium 201: 60°

[0188] S3: Use an ultrasonic cleaner to clean and then dry the friction mechanism 30 in the composite friction and wear specimen 100, and then use a balance with an accuracy of one ten-thousandth to weigh the friction components, and take the average value of 3 times;

[0189] S4: Install the experimental device

[0190] (1) Connect the three parts (driving mechanism 10, fastening mechanism 20, friction mechanism 30) of the composite friction and wear specimen 100 through threads and slots, and use an iron rod to penetrate the through holes reserved on the driving mechanism 10 and the fastening mechanism 20 for fastening;

[0191] (2) Connect the composite friction and wear specimen 100 with the connecting shaft 200 through threads, and use an iron rod to penetrate the through hole reserved on the driving mechanism 10 for fastening;

[0192] (3) Install two corresponding friction media 201 at the designated positions of the friction and wear testing machine (experimental device) and fix them.

[0193] (4) Adjust the reciprocating motion mechanism of the friction and wear testing machine so that the upper end of the friction mechanism 30 in the composite friction and wear specimen 100 is flush with the friction medium 201.

[0194] (5) Set the pressure loads on both sides of the friction medium 201 according to the experimental requirements and apply them to the target value, so that the two friction media 201 tightly clamp the composite friction and wear specimen 100. Then, place the composite friction and wear specimen 100 and the friction medium 201 into the drilling fluid.

[0195] S5: Set the operating values of the friction and wear testing machine according to the experimental parameters determined in S2.

[0196] S6: Start the experiment, so that the friction mechanism 30 is always within the height range of the friction medium 201, contact with the friction medium 201 and carry out friction and wear.

[0197] S7: When it reaches 300 min, stop the experiment, remove the friction mechanism 30 in the composite friction and wear specimen 100, clean, dry and weigh it to determine the friction weight loss. Then, use a wire cutting device (not shown) to cut out the part of the friction mechanism 30 that needs to observe the microscopic morphology, and then use a scanning electron microscope (not shown) to observe the microscopic morphology and obtain relevant data.

[0198] S8: The experiment ends.

[0199] The following introduces the fourth embodiment of the present invention: the friction and wear between the drill pipe (composite friction and wear specimen 100) and the formation during horizontal well drilling.

[0200] During horizontal well drilling, the drill pipe rotates and advances forward. Under the action of its own gravity and the reverse pressure of the formation, the drill pipe bends, contacts the formation, and generates friction and wear. The friction and wear form is a composite friction mode combining reciprocating friction and rotational friction.

[0201] S1: Select the main research objectives according to the drilling construction stage, operation area, and nature of the oil and gas reservoir:

[0202] (1) Composite friction and wear specimen 100: drill pipe, made of G105 steel;

[0203] (2) Friction medium 201: rock;

[0204] (3) Friction and wear mode: composite friction (axial reciprocating motion and rotational motion are carried out simultaneously).:

[0205] S2: Define the friction and wear experimental parameters according to the research requirements

[0206] (1) Outer diameter of the composite friction and wear specimen: 20 mm;

[0207] (2) Rotational speed: 20 r / min;

[0208] (3) Axial reciprocating speed: 0.2 m / s;

[0209] (4) Axial reciprocating stroke: 40 mm;

[0210] (5) Axial reciprocating frequency: 5 Hz;

[0211] (6) Lateral load: 80 KN;

[0212] (7) Height of the friction medium 201: 60 mm;

[0213] (8) Groove radian of the friction medium 201: 90°

[0214] S3: After cleaning and drying the friction mechanism 30 in the composite friction and wear specimen 100 using an ultrasonic cleaner, weigh the friction assembly using a balance with an accuracy of one ten-thousandth, and take the average value of 3 measurements;

[0215] S4: Install the experimental device

[0216] (1) Connect the three parts (driving mechanism 10, fastening mechanism 20, friction mechanism 30) of the composite friction and wear specimen 100 through threads and slots, and use an iron rod to extend into the through holes reserved on the driving mechanism 10 and the fastening mechanism 20 for fastening;

[0217] (2) Connect the composite friction and wear specimen 100 to the connecting shaft 200 through threads, and use an iron rod to extend into the through hole reserved on the driving mechanism 10 for fastening;

[0218] (3) Install two corresponding friction media 201 at the designated positions on the friction and wear testing machine (experimental device) and fix them;

[0219] (4) Adjust the reciprocating motion mechanism of the friction and wear testing machine to make the upper end of the friction mechanism 30 in the composite friction and wear specimen 100 level with the friction medium 201;

[0220] (5) Set the pressure loads on both sides of the friction medium 201 according to the experimental requirements and apply them to the target value to tightly clamp the composite friction and wear specimen 100 with the two friction media 201, and then place the composite friction and wear specimen 100 and the friction medium 201 into the drilling fluid;

[0221] S5: Set the operating values of the friction and wear testing machine according to the experimental parameters determined in S2;

[0222] S6: Start the experiment, ensuring that the friction mechanism 30 is always within the height range of the friction medium 201, make contact with the friction medium 201, and conduct friction and wear tests.

[0223] S7: When it reaches 300 minutes, stop the experiment, remove the friction mechanism 30 from the composite friction and wear specimen 100, clean, dry, and weigh it to determine the friction weight loss. Then, use a wire cutting device (not shown) to cut out the part of the friction mechanism 30 that needs to observe the microscopic morphology, and then use a scanning electron microscope (not shown) to observe the microscopic morphology and obtain relevant data.

[0224] S8: The experiment ends.

[0225] The following introduces the fifth embodiment of the present invention: the friction and wear between the polished rod (composite friction and wear specimen 100) and the casing during oil well production

[0226] During oil well production, the polished rod of the sucker rod pump reciprocates up and down to extract crude oil to the ground. Once the polished rod bends and contacts the casing, resulting in friction and wear failure, it will seriously affect the production of the oil well.

[0227] S1: Select the main research objectives according to the drilling construction stage, operation area, and reservoir properties:

[0228] (1) Composite friction and wear specimen 100: polished rod, made of P110 steel;

[0229] (2) Friction medium 201: casing, made of N80 steel;

[0230] (3) Friction and wear method: reciprocating friction (axial reciprocating motion and rotational motion are carried out simultaneously).

[0231] S2: Define the friction and wear test parameters according to the research requirements

[0232] (1) Outer diameter of the composite friction and wear specimen: 30 mm

[0233] (3) Axial reciprocating speed: 0.25 m / s

[0234] (4) Axial reciprocating stroke: 50 mm

[0235] (5) Axial reciprocating frequency: 5 Hz

[0236] (6) Lateral load: 10 KN

[0237] (7) Height of the friction medium 201: 60 mm

[0238] (8) Groove radian of the friction medium 201: 120°

[0239] S3: After cleaning the friction mechanism 30 in the composite friction and wear specimen 100 using an ultrasonic cleaner and drying it, weigh the friction assembly using a balance with an accuracy of one ten-thousandth, and take the average value of three measurements.

[0240] S4: Install the experimental device.

[0241] (1) Connect the three parts (driving mechanism 10, fastening mechanism 20, and friction mechanism 30) of the composite friction and wear specimen 100 through threads and slots, and use an iron rod to extend into the through holes reserved on the driving mechanism 10 and the fastening mechanism 20 for fastening.

[0242] (2) Connect the composite friction and wear specimen 100 to the connecting shaft 200 through threads, and use an iron rod to extend into the through hole reserved on the driving mechanism 10 for fastening.

[0243] (3) Install two corresponding friction media 201 at the designated positions on the friction and wear testing machine (experimental device) and fix them.

[0244] (4) Adjust the reciprocating motion mechanism of the friction and wear testing machine so that the upper end of the friction mechanism 30 in the composite friction and wear specimen 100 is flush with the friction medium 201.

[0245] (5) Set the pressure loads on both sides of the friction medium 201 according to the experimental requirements and apply them to the target value so that the two friction media 201 tightly clamp the composite friction and wear specimen 100, and then place the composite friction and wear specimen 100 and the friction medium 201 into the drilling fluid.

[0246] S5: Set the operating values of the friction and wear testing machine according to the experimental parameters determined in S2.

[0247] S6: Start the experiment, so that the friction mechanism 30 is always within the height range of the friction medium 201, contact with the friction medium 201 and carry out friction and wear.

[0248] S7: When it reaches 300 minutes, stop the experiment, remove the friction mechanism 30 in the composite friction and wear specimen 100, clean, dry, and weigh it to determine the friction weight loss; then, use a wire cutting device (not shown) to cut out the part of the friction mechanism 30 that needs to observe the microtopography, and then use a scanning electron microscope (not shown) to observe the microtopography and obtain relevant data.

[0249] S8: The experiment ends.

[0250] Compared with the prior art, the advantages of the present invention are:

[0251] First, the present invention can achieve various friction and wear motion forms for complex working conditions in oil and gas drilling and production. For example, it can perform axial reciprocating motion alone, rotational motion alone, and compound motion (i.e., axial reciprocating motion and rotational motion simultaneously). Moreover, by reasonably setting test parameters and usage methods, it ensures that the friction mechanism 30 in the composite friction and wear specimen 100 can always be in contact with the friction medium 20 and conduct friction and wear, achieving uniform friction throughout the entire process of the target and further eliminating the situation of the friction halving region.

[0252] Second, the composite friction and wear specimen 100 in the present invention is constructed as a split specimen, that is, it consists of three sequentially connected parts (the driving mechanism 10, the fastening mechanism 20, and the friction mechanism 30). Compared with the prior art, it can not only reduce the mass and volume of the specimen to be measured but also improve the fault tolerance rate of the experiment.

[0253] In addition, since during composite friction (axial reciprocating motion and / or rotational motion), the composite friction and wear specimen 100 can be in full contact with the friction medium 201 and perform reciprocating relative motion to ensure that the entire surface of the composite friction and wear specimen 100 can achieve uniform and sufficient friction. Therefore, when measuring the friction and wear mass of the composite friction and wear specimen 100, it is only necessary to directly measure the friction mechanism 30. In this way, it not only effectively reduces the mass and volume of the specimen to be measured but also improves the measurement accuracy of the friction and wear mass of the specimen.

[0254] The above is only the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art can easily make changes or variations within the disclosure scope of the present invention, and such changes or variations should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A composite friction and wear specimen, comprising: A driving mechanism (10) for connecting with a connecting shaft (200), the driving mechanism (10) includes a first connecting member (11), and a plurality of grooves (12) arranged at intervals in the circumferential direction at the lower end surface of the first connecting member (11), A fastening mechanism (20) arranged below the driving mechanism (10), and A friction mechanism (30) arranged between the driving mechanism (10) and the fastening mechanism (20), which includes a friction portion (31) configured in an annular form, and a locking portion (32) arranged on the upper end surface of the friction portion (31) and adapted to the groove (12).

2. The composite friction and wear specimen according to claim 1, characterized in that, The first connecting member (11) is configured in a cylindrical form, the fastening mechanism (20) includes a fastener (21) configured in a columnar form, and a locking member (22) extending axially upward along the fastener (21), Wherein, the locking member (22) is configured to be able to extend into the first connecting member (11) so that a sealed connection is formed between the friction portion (31) and both the first connecting member (11) and the fastener (21).

3. The composite friction and wear specimen according to claim 2, characterized in that, The driving mechanism (10) further includes a second connecting member (13) extending axially upward along the first connecting member (11), and the driving mechanism (10) is configured to be able to form a threaded connection with the connecting shaft (200) through the second connecting member (13).

4. The composite friction and wear specimen according to claim 3, wherein A stepped surface (111) extending radially inward and adapted to abut against the connecting shaft (200) is formed at the joint of the first connecting member (11) and the second connecting member (13).

5. The composite friction and wear specimen according to claim 4, characterized in that, The outer diameters of the first connecting member (11), the friction portion (31) and the fastener (21) are all equal.

6. The composite friction and wear specimen according to claim 5, characterized in that, The outer diameter of the friction portion (31) is in the range of 20 mm to 30 mm.

7. The composite friction and wear specimen according to claim 6, wherein The composite friction and wear specimen includes through holes provided on the first connecting member (11) and the fastener (21), and an iron rod adapted to the through holes and rotationally fastened.

8. An experimental device for simulating oil and gas drilling and production conditions, comprising a composite friction and wear specimen according to any one of claims 1 to 7, a connecting shaft (200) for forming a threaded connection with the composite friction and wear specimen, and a friction medium (201) for clamping the composite friction and wear specimen, wherein, The inner circumferential surface of the friction medium (201) forms a sealed connection with the outer circumferential surface of the composite friction and wear specimen.

9. The experimental device according to claim 8, characterized in that, The connecting shaft (200) includes a first connecting shaft portion (210) connected to the composite friction and wear specimen, a second connecting shaft portion (220) connected to an external driving mechanism, and a third connecting shaft portion (230) arranged between the first connecting shaft portion (210) and the second connecting shaft portion (220), wherein the outer diameter of the third connecting shaft portion (230) gradually increases in the direction from the first connecting shaft portion (210) to the second connecting shaft portion (220).

10. The experimental device according to claim 9, characterized in that, The external driving mechanism includes an axially reciprocating device and a rotator, and an installation portion (221) extending radially outward and adapted to axially abut against the rotator is provided on the second connecting shaft portion (220). The connecting shaft (200) further includes a plurality of card slot portions (222) that are circumferentially spaced apart on the second connecting shaft portion (220) and are adapted to cooperate with the rotator, and an engaging portion (223) that is disposed above the card slot portion (222) and is adapted to form a threaded connection with the axial reciprocator, wherein the card slot portion (222) is above the mounting portion (221).

11. A method for simulating oil and gas drilling and production working conditions by using the experimental device according to any one of claims 8 to 10, comprising the following steps: S1. Connect the connecting shaft (200) to the composite friction and wear specimen; clamp the composite friction and wear specimen through the friction medium (201); S2. Set various experimental parameters; cause the composite friction and wear specimen to undergo different types of friction and wear within the height range of the friction medium (201) through the connecting shaft (200); S3. Remove the friction mechanism from the composite friction and wear specimen and clean, dry, and weigh it to determine the friction weight loss; obtain microscopic friction and wear morphology data by cutting the friction mechanism.

12. The method according to claim 11, wherein The friction and wear modes in step S2 include axial reciprocating motion and / or rotational motion.

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