Oil and gas string abrasion testing device and method

Abstract

The invention discloses an oil and gas string abrasion testing device which comprises a supporting seat, and a simulation shaft assembly, a composite motion mechanism, a contact load applying mechanism and an abrasion measuring mechanism are arranged on the supporting seat. The simulation wellbore assembly comprises a simulation wellbore cavity which is connected with a fluid supply mechanism. The composite motion mechanism comprises a positioning shaft and a power assembly driving the positioning shaft to move. The positioning shaft is located on the upper portion of the simulation shaft cavity. The contact load applying mechanism comprises two symmetrical clamping thrust plates used for clamping an outer sample and an applying assembly used for providing clamping force and lateral force, and the part, used for clamping the outer sample, of each clamping thrust plate is located in the simulation shaft cavity. The invention further discloses an oil and gas pipe column abrasion testing method. According to the invention, multi-medium curved surface friction contact of friction between the drill rod and the sleeve and friction between the sleeve and well wall rock mass can be simulated, so that experimental support is provided for subsequent safety evaluation of the sleeve and safety guarantee of a shaft in a full life cycle.

Description

Technical Field

[0001] The invention belongs to the technical field of pipe string wear testing in the process of oil and gas field development and drilling, and in particular relates to an oil and gas pipe string wear testing device and method. Background Art

[0002] With the development of deep and ultra-deep fractured gas reservoirs, the proportion of directional wells, extended reach wells, horizontal wells, and deep wells has increased. The characteristics of high wellbore curvature, large wellbore deformation, and complex drilling fluid system are prominent, resulting in: (1) During the drilling process, the outer wall of the drill pipe contacts the inner wall of the upper secondary casing at multiple angles, and rotates and rubs in a complex drilling fluid environment (viscosity increases), damaging the inner wall of the casing; (2) During the process of drilling, the outer wall of the drill pipe contacts the inner wall of the casing head-on, reciprocating friction, damaging the inner wall of the casing; (3) During the process of casing lowering, the outer wall of the casing contacts the wellbore rock mass, and there is reciprocating and rotating composite friction of lifting and pressing up and down, causing outer wall wear damage. The above three processes seriously damage the casing wall, and there is a risk of wall wear failure, resulting in leakage accidents. Therefore, it is urgent to test the wear of the casing to prevent subsequent leakage accidents.

[0003] Existing testing devices and methods for casing friction and wear are mostly completed by a pin-type testing machine. The wear test between two planes performed by the pin-type testing machine cannot effectively simulate the on-site working conditions (friction between two curved rings).

[0004] Based on the above problems, the present application proposes an oil and gas pipe wear testing device and method, which can simulate the curved friction contact between the drill pipe and the casing, and the friction between the casing and the well wall rock, thereby providing experimental support for the subsequent casing safety evaluation and the safety assurance of the wellbore throughout its life cycle. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide an oil and gas pipe string wear testing device.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] An oil and gas pipe string wear test device, comprising a support seat, on which a simulated wellbore assembly for simulating the physical environment of the wellbore is arranged, a composite motion mechanism for driving an inner sample to perform up and down reciprocating motion or rotational motion or up and down reciprocating and rotational composite motion, a contact load applying mechanism for clamping an outer sample and applying a lateral force to a contact surface between the outer sample and the inner sample, and a wear measuring mechanism for measuring the wear amount of the inner sample or the outer sample;

[0008] The simulated wellbore assembly comprises a simulated wellbore cavity fixedly arranged on a support seat, and the simulated wellbore cavity is connected to a fluid supply mechanism for providing simulated wellbore fluid;

[0009] The composite motion mechanism comprises a positioning shaft for mounting the internal sample and a power assembly for driving the positioning shaft to move, wherein the positioning shaft is located at the upper part of the simulated wellbore cavity;

[0010] The contact load applying mechanism comprises two symmetrical clamping thrust plates for clamping the external sample and an applying assembly for providing clamping force and lateral force. The part of the clamping thrust plate for clamping the external sample is located in the simulated wellbore cavity.

[0011] Preferably, the support seat comprises a transparent cover, and a support frame is arranged on the top of the transparent cover;

[0012] The top of the simulated wellbore cavity is fixedly connected to the bottom end of the top plate of the transparent cover, and a through hole matching the wellhead of the simulated wellbore cavity is arranged on the top plate of the transparent cover.

[0013] Preferably, the fluid supply mechanism comprises a liquid storage tank for storing drilling fluid and a sand adding tank for storing rock cuttings;

[0014] The outlet pipe of the liquid storage tank and the outlet pipe of the sand adding tank are connected to the inlet pipe of the hydraulic pump after being collected;

[0015] The outlet pipe of the hydraulic pump is connected to one end of a liquid inlet pipeline, and the other end of the liquid inlet pipeline is connected to the bottom inlet of the simulated wellbore cavity.

[0016] Preferably, a one-way valve is provided on the liquid inlet pipeline, and the flow direction allowed in the one-way valve is from the hydraulic pump to the simulated wellbore cavity.

[0017] Preferably, a micro-agitator is provided at the inner bottom end of the simulated wellbore cavity.

[0018] Preferably, a heating wire is provided on the outer wall of the simulated wellbore cavity.

[0019] Preferably, the power assembly comprises a reciprocating loading cylinder fixedly arranged on the support frame, and the piston rod end of the reciprocating loading cylinder is rotationally matched with the turntable;

[0020] Two guide rods are vertically fixed at the bottom end of the turntable;

[0021] The guide rod and the first pulley are slidably matched in the vertical direction;

[0022] The lower part of the outer wall of the first pulley is rotatably matched with the support frame; the upper part of the outer wall of the first pulley is connected to a driving component used to drive the first pulley to rotate;

[0023] The bottom end of the guide rod is fixedly connected to the connecting plate;

[0024] The positioning shaft is fixedly arranged at the bottom end of the connecting plate, and the positioning shaft is coaxially arranged with the first pulley.

[0025] Preferably, the driving assembly comprises a driving motor fixedly mounted on the supporting frame, and the output shaft end of the driving motor is coaxially fixedly connected to the second pulley;

[0026] A transmission belt is arranged between the upper portion of the outer side wall of the first pulley and the outer side wall of the second pulley.

[0027] Preferably, the applying assembly comprises two loading cylinders respectively connected to corresponding clamping thrust plates;

[0028] The loading cylinder is fixedly arranged on the supporting frame;

[0029] The piston rod of the loading cylinder is fixedly connected to the corresponding clamping thrust plate.

[0030] Preferably, the clamping thrust plate comprises a connecting portion for connecting to the loading cylinder, a mounting portion for mounting the external specimen, and an adapter plate for connecting the mounting portion and the connecting portion;

[0031] The installation portion is located in the simulated wellbore cavity.

[0032] Preferably, the mounting portion is provided with a slot for placing an external sample, and the two slots for clamping the thrust plates are arranged facing each other.

[0033] Preferably, the wear measuring mechanism includes a displacement sensor and a weighing instrument for weighing the inner sample and the outer sample before and after the test;

[0034] There are two displacement sensors, which are respectively arranged on two loading cylinders.

[0035] The invention also discloses a method for testing oil and gas pipe string wear.

[0036] A method for testing wear of an oil and gas pipe string is implemented using an oil and gas pipe string wear testing device, and comprises the following steps:

[0037] Step 11: According to the actual sizes of casing, drill pipe and well wall in the target work area, the sizes of the inner sample and the outer sample are determined according to the similarity principle, wherein the materials used for the inner sample and the outer sample are the same as those in the target work area; the corresponding inner sample and the outer sample are prepared according to the size and material and weighed respectively by a weighing instrument to obtain the initial weight of the inner sample and the initial weight of the outer sample;

[0038] Step 12: Determine the test temperature in the simulated wellbore cavity and the amount of sand carried by the fluid entering the simulated wellbore cavity according to the downhole temperature of the target work area, the drilling fluid system, and the particle size of the rock cuttings;

[0039] Step 13: Determine the rotation speed of the inner sample according to the drilling pipe rotation speed or the casing running rotation speed and the size scaling ratio.

[0040] Step 14: Use Landmark wellplan software to calculate the lateral force on the drill pipe or casing in the target work area, and then determine the lateral contact force of the sample based on the stress similarity principle;

[0041] Step 15: According to the drilling speed of the drill pipe or the lifting and lowering speed of the casing in the target work area, the up and down reciprocating speed of the internal sample is determined based on the similarity principle;

[0042] Step 16: Determine the inclination angle of the inner hole centerline of the outer sample according to the wellbore trajectory inclination angle in the target work area;

[0043] Step 17: Inject the mixed fluid into the simulated wellbore cavity according to the drilling fluid, cuttings particle size, and sand carrying capacity of the fluid determined in step 12, and turn on the micro-agitator at the same time;

[0044] Step 18: Using the heating wire, the temperature in the simulated wellbore cavity reaches the test temperature determined in step 12;

[0045] Step 19: The inner sample determined in step 11 is fixedly connected to the positioning shaft, and the outer sample determined in step 11 is clamped between two clamping thrust plates;

[0046] Step 20: First, applying the sample contact lateral force determined in step 14 to the contact surface between the inner sample and the outer sample through one of the loading cylinders;

[0047] Then start the reciprocating loading cylinder to make the internal sample reciprocate up and down at the up and down reciprocating speed determined in step 15;

[0048] Finally, the driving motor is started to rotate the internal sample at the rotation speed determined in step 13;

[0049] The timing starts from the time when the inner sample starts to move until the friction and wear test reaches the set test time; during this process, the displacement sensor detects the change in the distance between the corresponding side clamping thrust plate and the positioning axis;

[0050] Step 21: After the set test time is reached, the loading cylinder, the reciprocating loading cylinder and the driving motor are turned off in sequence;

[0051] Step 22: Stop heating the heating wire, remove the one-way valve after the temperature cools down, and drain the sand-carrying mud in the simulated wellbore cavity;

[0052] Step 23: Take out the outer sample, dismantle the inner sample, and weigh the inner sample and the outer sample after the test using a weighing instrument to obtain the final weight of the inner sample and the final weight of the outer sample.

[0053] Step 24: The sum of the distance changes between the two clamping thrust plates and the positioning axis is taken as the wear depth of the contact surface of the specimen;

[0054] The difference between the initial weight and the final weight of the internal sample is taken as the wear change of the internal sample;

[0055] The difference between the initial weight and the final weight of the external specimen is taken as the wear change of the external specimen.

[0056] The beneficial effects of the present invention are:

[0057] The present invention fully considers the wear environment coupled with complex working conditions faced by the casing string during wellbore operations, changes the previous simulation of only a single rotational friction motion form, and realizes the reciprocating-rotational composite friction motion form between the inner sample and the outer sample through the setting of the composite motion mechanism. It can be used to simulate the casing wall wear process under rotation, reciprocating and the composite form of the two, and then can simulate the multi-medium curved surface friction contact of the friction between the drill pipe and the casing, and the friction between the casing and the well wall rock, thereby providing experimental support for the subsequent casing safety evaluation and the safety guarantee of the wellbore throughout the life cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0059] Figure 1 It is a structural schematic diagram of the oil and gas pipe string wear testing device of the present invention;

[0060] Figure 2 It is a schematic diagram of the structure of the clamping thrust plate in the present invention;

[0061] Figure 3 is a graph showing the change of friction force obtained in Example 6 with the test time;

[0062] Figure 4 is a graph showing the variation of the friction force obtained in Example 7 with the test time;

[0063] in:

[0064] 01-Internal sample;

[0065] 02-External specimen;

[0066] 1-Simulated wellbore cavity;

[0067] 2-Liquid storage tank;

[0068] 3- Add sand tank;

[0069] 4-Hydraulic pump;

[0070] 5-Liquid inlet pipeline;

[0071] 51- one-way valve;

[0072] 6- Transparent cover;

[0073] 7- Support frame;

[0074] 8- Micro stirrer;

[0075] 9- heating wire;

[0076] 10- reciprocating loading cylinder;

[0077] 11- Turntable;

[0078] 12-guide rod;

[0079] 13- first pulley;

[0080] 14- positioning axis;

[0081] 15-clamping thrust plate;

[0082] 151-connecting part;

[0083] 152-installation part;

[0084] 153-adapter board;

[0085] 154-card slot;

[0086] 16-connecting plate;

[0087] 17- driving motor;

[0088] 18- second pulley;

[0089] 19- transmission belt;

[0090] 20- loading cylinder;

[0091] 21-Guide cylinder. DETAILED DESCRIPTION

[0092] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0093] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0094] In the present invention, the directions or positional relationships indicated by terms such as "upper", "lower", "bottom", "top", etc. are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention. They do not specifically refer to any part or element in the present invention and cannot be understood as limitations on the present invention.

[0095] In the present invention, terms such as "connected" and "connection" should be understood in a broad sense, indicating that the connection can be fixed, integral or detachable; it can be directly connected or indirectly connected through an intermediate medium. Relevant scientific research or technical personnel in this field can determine the specific meaning of the above terms in the present invention according to specific circumstances, and they should not be understood as limiting the present invention.

[0096] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0097] Embodiment 1:

[0098] like Figure 1 As shown, an oil and gas pipe string wear test device includes a support seat, on which a simulated wellbore assembly for simulating the physical environment of the wellbore is arranged, a composite motion mechanism for driving an inner sample 01 to perform up and down reciprocating motion or rotational motion or up and down reciprocating and rotational composite motion, a contact load applying mechanism for clamping an outer sample 02 and applying a lateral force to the contact surface between the outer sample 02 and the inner sample 01, and a wear measuring mechanism for measuring the wear amount of the inner sample 01 or the outer sample 02;

[0099] The simulated wellbore assembly includes a simulated wellbore cavity 1 fixedly arranged on a support seat. The simulated wellbore cavity 1 in the present application is a corrosion-resistant and high-temperature resistant metal cylindrical shell. The simulated wellbore cavity 1 is connected to a fluid supply mechanism for providing simulated wellbore fluid, wherein the simulated wellbore fluid is a mixed fluid of drilling fluid and rock cuttings; an external sample 02 and simulated wellbore fluid are placed inside the simulated wellbore cavity 1;

[0100] The composite motion mechanism includes a positioning shaft 14 for mounting the internal sample 01 and a power assembly for driving the positioning shaft 14 to move, wherein the positioning shaft 14 is located at the upper part of the simulated wellbore cavity 1;

[0101] The contact load application mechanism includes two symmetrical clamping thrust plates 15 for clamping the external sample 02 and an application component for providing clamping force and lateral force. The portion of the clamping thrust plates 15 for clamping the external sample 02 is located in the simulated wellbore cavity 1.

[0102] Preferably, the support seat comprises a transparent cover 6, and a support frame 7 is arranged on the top of the transparent cover 6;

[0103] The top of the simulated wellbore cavity 1 is fixedly connected to the bottom end of the top plate of the transparent cover 6 , and a through hole matching the wellhead of the simulated wellbore cavity 1 is provided on the top plate of the transparent cover 6 .

[0104] Preferably, the fluid supply mechanism comprises a liquid storage tank 2 for storing drilling fluid and a sand adding tank 3 for storing rock cuttings;

[0105] The outlet pipe of the liquid storage tank 2 and the outlet pipe of the sand adding tank 3 are connected to the inlet pipe of the hydraulic pump 4 after being collected;

[0106] The outlet pipe of the hydraulic pump 4 is connected to one end of the liquid inlet pipeline 5 , and the other end of the liquid inlet pipeline 5 is connected to the bottom inlet of the simulated wellbore cavity 1 .

[0107] Specifically, valves are provided on the outlet pipe of the liquid storage tank 2 and the outlet pipe of the sand adding tank 3.

[0108] Preferably, a one-way valve 51 is provided on the liquid inlet pipeline 5 , and the allowed flow direction in the one-way valve 51 is from the hydraulic pump 4 to the simulated wellbore cavity 1 .

[0109] Preferably, a micro-stirrer 8 is provided at the inner bottom end of the simulated wellbore cavity 1, and the micro-stirrer 8 is used to stir the simulated wellbore fluid composed of drilling fluid and cuttings in the simulated wellbore cavity 1, so as to simulate the wellbore fluid movement environment.

[0110] Preferably, a heating wire 9 is provided on the outer wall of the simulated wellbore cavity 1 to achieve temperature control of the simulated wellbore cavity 1 .

[0111] Embodiment 2:

[0112] like Figure 1 As shown, an oil and gas pipe string wear test device includes a support seat, on which a simulated wellbore assembly for simulating the physical environment of the wellbore is arranged, a composite motion mechanism for driving an inner sample 01 to perform up and down reciprocating motion or rotational motion or up and down reciprocating and rotational composite motion, a contact load applying mechanism for clamping an outer sample 02 and applying a lateral force to the contact surface between the outer sample 02 and the inner sample 01, and a wear measuring mechanism for measuring the wear amount of the inner sample 01 or the outer sample 02;

[0113] The simulated wellbore assembly includes a simulated wellbore cavity 1 fixedly arranged on a support seat. The simulated wellbore cavity 1 in the present application is a corrosion-resistant and high-temperature resistant metal cylindrical shell. The simulated wellbore cavity 1 is connected to a fluid supply mechanism for providing simulated wellbore fluid, wherein the simulated wellbore fluid is a mixed fluid of drilling fluid and rock cuttings; an external sample 02 and simulated wellbore fluid are placed inside the simulated wellbore cavity 1;

[0114] The composite motion mechanism includes a positioning shaft 14 for mounting the internal sample 01 and a power assembly for driving the positioning shaft 14 to move, wherein the positioning shaft 14 is located at the upper part of the simulated wellbore cavity 1;

[0115] The contact load application mechanism includes two symmetrical clamping thrust plates 15 for clamping the external sample 02 and an application component for providing clamping force and lateral force. The portion of the clamping thrust plates 15 for clamping the external sample 02 is located in the simulated wellbore cavity 1.

[0116] Preferably, the support seat comprises a transparent cover 6, and a support frame 7 is arranged on the top of the transparent cover 6;

[0117] The top of the simulated wellbore cavity 1 is fixedly connected to the bottom end of the top plate of the transparent cover 6 , and a through hole matching the wellhead of the simulated wellbore cavity 1 is provided on the top plate of the transparent cover 6 .

[0118] Preferably, the fluid supply mechanism comprises a liquid storage tank 2 for storing drilling fluid and a sand adding tank 3 for storing rock cuttings;

[0119] The outlet pipe of the liquid storage tank 2 and the outlet pipe of the sand adding tank 3 are connected to the inlet pipe of the hydraulic pump 4 after being collected;

[0120] The outlet pipe of the hydraulic pump 4 is connected to one end of the liquid inlet pipeline 5 , and the other end of the liquid inlet pipeline 5 is connected to the bottom inlet of the simulated wellbore cavity 1 .

[0121] Specifically, valves are provided on the outlet pipe of the liquid storage tank 2 and the outlet pipe of the sand adding tank 3.

[0122] Preferably, a one-way valve 51 is provided on the liquid inlet pipeline 5 , and the allowed flow direction in the one-way valve 51 is from the hydraulic pump 4 to the simulated wellbore cavity 1 .

[0123] Preferably, a micro-stirrer 8 is provided at the inner bottom end of the simulated wellbore cavity 1, and the micro-stirrer 8 is used to stir the simulated wellbore fluid composed of drilling fluid and cuttings in the simulated wellbore cavity 1, so as to simulate the wellbore fluid movement environment.

[0124] Preferably, a heating wire 9 is provided on the outer wall of the simulated wellbore cavity 1 to achieve temperature control of the simulated wellbore cavity 1 .

[0125] Preferably, the power assembly includes a reciprocating loading cylinder 10 fixedly arranged on the support frame 7, and the piston rod end of the reciprocating loading cylinder 10 is rotationally matched with the turntable 11. Specifically, the piston rod end of the reciprocating loading cylinder 10 is rotationally matched with the turntable 11 through a bearing;

[0126] Two guide rods 12 are vertically fixedly arranged at the bottom end of the rotating disk 11;

[0127] The guide rod 12 and the first pulley 13 are slidably matched in the vertical direction. Specifically, the guide rod 12 and the first pulley 13 are slidably matched in the vertical direction through a linear bearing.

[0128] The lower part of the outer wall of the first pulley 13 is rotatably matched with the support frame 7. Specifically, the lower part of the outer wall of the first pulley 13 is rotatably matched with the support frame 7 through a bearing; the upper part of the outer wall of the first pulley 13 is connected to a driving component used to drive the first pulley 13 to rotate;

[0129] The bottom end of the guide rod 12 is fixedly connected to the connecting plate 16;

[0130] The positioning shaft 14 is fixedly arranged at the bottom end of the connecting plate 16, and the positioning shaft 14 is coaxially arranged with the first pulley 13;

[0131] Preferably, the driving assembly comprises a driving motor 17 fixedly mounted on the supporting frame 7, and the output shaft end of the driving motor 17 is coaxially fixedly connected to the second pulley 18;

[0132] A transmission belt 19 is disposed between an upper portion of an outer side wall of the first pulley 13 and an outer side wall of the second pulley 18 .

[0133] When the driving motor 17 is not running and the reciprocating loading cylinder 10 is running: the piston rod of the reciprocating loading cylinder 10 drives the positioning shaft 14 to reciprocate up and down through the turntable 11, the guide rod 12, and the connecting plate 16. When the internal sample 01 is installed on the positioning shaft 14, the internal sample 01 is reciprocated up and down.

[0134] When the driving motor 17 is running and the reciprocating loading cylinder 10 is not running: the driving motor 17 drives the second pulley 18 to rotate, the second pulley 18 drives the first pulley 13 to rotate through the transmission belt 19, the rotation of the first pulley 13 drives the turntable 11 and the connecting plate 16 to rotate through the guide rod 12, and finally realizes the rotation movement of the positioning shaft 14; when the internal sample 01 is installed on the positioning shaft 14, the rotation movement of the internal sample 01 is finally realized;

[0135] When the driving motor 17 and the reciprocating loading cylinder 10 are running, the positioning shaft 14 realizes the up and down reciprocating rotation compound motion. When the internal sample 01 is installed on the positioning shaft 14, the up and down reciprocating rotation compound motion of the internal sample 01 is finally realized.

[0136] Embodiment 3:

[0137] like Figure 1 As shown, an oil and gas pipe string wear test device includes a support seat, on which a simulated wellbore assembly for simulating the physical environment of the wellbore is arranged, a composite motion mechanism for driving an inner sample 01 to perform up and down reciprocating motion or rotational motion or up and down reciprocating and rotational composite motion, a contact load applying mechanism for clamping an outer sample 02 and applying a lateral force to the contact surface between the outer sample 02 and the inner sample 01, and a wear measuring mechanism for measuring the wear amount of the inner sample 01 or the outer sample 02;

[0138] The simulated wellbore assembly includes a simulated wellbore cavity 1 fixedly arranged on a support seat. The simulated wellbore cavity 1 in the present application is a corrosion-resistant and high-temperature resistant metal cylindrical shell. The simulated wellbore cavity 1 is connected to a fluid supply mechanism for providing simulated wellbore fluid, wherein the simulated wellbore fluid is a mixed fluid of drilling fluid and rock cuttings; an external sample 02 and simulated wellbore fluid are placed inside the simulated wellbore cavity 1;

[0139] The composite motion mechanism includes a positioning shaft 14 for mounting the internal sample 01 and a power assembly for driving the positioning shaft 14 to move, wherein the positioning shaft 14 is located at the upper part of the simulated wellbore cavity 1;

[0140] The contact load application mechanism includes two symmetrical clamping thrust plates 15 for clamping the external sample 02 and an application component for providing clamping force and lateral force. The portion of the clamping thrust plates 15 for clamping the external sample 02 is located in the simulated wellbore cavity 1.

[0141] Preferably, the support seat comprises a transparent cover 6, and a support frame 7 is arranged on the top of the transparent cover 6;

[0142] The top of the simulated wellbore cavity 1 is fixedly connected to the bottom end of the top plate of the transparent cover 6 , and a through hole matching the wellhead of the simulated wellbore cavity 1 is provided on the top plate of the transparent cover 6 .

[0143] Preferably, the fluid supply mechanism comprises a liquid storage tank 2 for storing drilling fluid and a sand adding tank 3 for storing rock cuttings;

[0144] The outlet pipe of the liquid storage tank 2 and the outlet pipe of the sand adding tank 3 are connected to the inlet pipe of the hydraulic pump 4 after being collected;

[0145] The outlet pipe of the hydraulic pump 4 is connected to one end of the liquid inlet pipeline 5 , and the other end of the liquid inlet pipeline 5 is connected to the bottom inlet of the simulated wellbore cavity 1 .

[0146] Specifically, valves are provided on the outlet pipe of the liquid storage tank 2 and the outlet pipe of the sand adding tank 3.

[0147] Preferably, a one-way valve 51 is provided on the liquid inlet pipeline 5 , and the allowed flow direction in the one-way valve 51 is from the hydraulic pump 4 to the simulated wellbore cavity 1 .

[0148] Preferably, a micro-stirrer 8 is provided at the inner bottom end of the simulated wellbore cavity 1, and the micro-stirrer 8 is used to stir the simulated wellbore fluid composed of drilling fluid and cuttings in the simulated wellbore cavity 1, so as to simulate the wellbore fluid movement environment.

[0149] Preferably, a heating wire 9 is provided on the outer wall of the simulated wellbore cavity 1 to achieve temperature control of the simulated wellbore cavity 1 .

[0150] Preferably, the power assembly includes a reciprocating loading cylinder 10 fixedly arranged on the support frame 7, and the piston rod end of the reciprocating loading cylinder 10 is rotationally matched with the turntable 11. Specifically, the piston rod end of the reciprocating loading cylinder 10 is rotationally matched with the turntable 11 through a bearing;

[0151] Two guide rods 12 are vertically fixedly arranged at the bottom end of the rotating disk 11;

[0152] The guide rod 12 and the first pulley 13 are slidably matched in the vertical direction. Specifically, the guide rod 12 and the first pulley 13 are slidably matched in the vertical direction through a linear bearing.

[0153] The lower part of the outer wall of the first pulley 13 is rotatably matched with the support frame 7. Specifically, the lower part of the outer wall of the first pulley 13 is rotatably matched with the support frame 7 through a bearing; the upper part of the outer wall of the first pulley 13 is connected to a driving component used to drive the first pulley 13 to rotate;

[0154] The bottom end of the guide rod 12 is fixedly connected to the connecting plate 16;

[0155] The positioning shaft 14 is fixedly arranged at the bottom end of the connecting plate 16, and the positioning shaft 14 is coaxially arranged with the first pulley 13;

[0156] Preferably, the driving assembly comprises a driving motor 17 fixedly mounted on the supporting frame 7, and the output shaft end of the driving motor 17 is coaxially fixedly connected to the second pulley 18;

[0157] A transmission belt 19 is disposed between an upper portion of an outer side wall of the first pulley 13 and an outer side wall of the second pulley 18 .

[0158] Preferably, the applying assembly comprises two loading cylinders 20 respectively connected to corresponding clamping thrust plates 15;

[0159] The loading cylinder 20 is fixedly arranged on the support frame 7;

[0160] The piston rod of the loading cylinder 20 is fixedly connected to the corresponding clamping thrust plate 15 to control the left and right movement of the corresponding clamping thrust plate 15 .

[0161] Specifically, the piston rod of the loading cylinder 20 is fixedly connected to the corresponding clamping thrust plate 15 via a guide cylinder 21 , and the guide cylinder 21 is slidably matched with the support frame 7 in the left-right direction.

[0162] Preferably, Figure 2 As shown, the clamping thrust plate 15 includes a connecting portion 151 for connecting with the loading cylinder 20, a mounting portion 152 for mounting the external specimen 02, and an adapter plate 153 for connecting the mounting portion 152 and the connecting portion 151;

[0163] The installation portion 152 is located in the simulated wellbore cavity 1 .

[0164] Preferably, the mounting portion 152 is provided with a slot 154 for placing the external sample 02 , and the two slots 154 for clamping the thrust plates 15 are arranged facing each other.

[0165] When in use, the two loading cylinders 20 control the two clamping thrust plates 15 to move toward each other until the outer sample 02 is clamped in the slot 154, and the inner sample 01 passes through the middle through hole of the outer sample 02; when lateral force needs to be applied, the corresponding side loading cylinder 20 applies lateral force to the contact surface between the outer sample 02 and the inner sample 01 through the clamping thrust plate 15 on the corresponding side, so as to simulate the lateral force bearing condition during the friction of the tubing in on-site downhole operations.

[0166] Embodiment 4:

[0167] like Figure 1 As shown, an oil and gas pipe string wear test device includes a support seat, on which a simulated wellbore assembly for simulating the physical environment of the wellbore is arranged, a composite motion mechanism for driving an inner sample 01 to perform up and down reciprocating motion or rotational motion or up and down reciprocating and rotational composite motion, a contact load applying mechanism for clamping an outer sample 02 and applying a lateral force to the contact surface between the outer sample 02 and the inner sample 01, and a wear measuring mechanism for measuring the wear amount of the inner sample 01 or the outer sample 02;

[0168] The simulated wellbore assembly includes a simulated wellbore cavity 1 fixedly arranged on a support seat. The simulated wellbore cavity 1 in the present application is a corrosion-resistant and high-temperature resistant metal cylindrical shell. The simulated wellbore cavity 1 is connected to a fluid supply mechanism for providing simulated wellbore fluid, wherein the simulated wellbore fluid is a mixed fluid of drilling fluid and rock cuttings; an external sample 02 and simulated wellbore fluid are placed inside the simulated wellbore cavity 1;

[0169] The composite motion mechanism includes a positioning shaft 14 for mounting the internal sample 01 and a power assembly for driving the positioning shaft 14 to move, wherein the positioning shaft 14 is located at the upper part of the simulated wellbore cavity 1;

[0170] The contact load application mechanism includes two symmetrical clamping thrust plates 15 for clamping the external sample 02 and an application component for providing clamping force and lateral force. The portion of the clamping thrust plates 15 for clamping the external sample 02 is located in the simulated wellbore cavity 1.

[0171] Preferably, the support seat comprises a transparent cover 6, and a support frame 7 is arranged on the top of the transparent cover 6;

[0172] The top of the simulated wellbore cavity 1 is fixedly connected to the bottom end of the top plate of the transparent cover 6 , and a through hole matching the wellhead of the simulated wellbore cavity 1 is provided on the top plate of the transparent cover 6 .

[0173] Preferably, the fluid supply mechanism comprises a liquid storage tank 2 for storing drilling fluid and a sand adding tank 3 for storing rock cuttings;

[0174] The outlet pipe of the liquid storage tank 2 and the outlet pipe of the sand adding tank 3 are connected to the inlet pipe of the hydraulic pump 4 after being collected;

[0175] The outlet pipe of the hydraulic pump 4 is connected to one end of the liquid inlet pipeline 5 , and the other end of the liquid inlet pipeline 5 is connected to the bottom inlet of the simulated wellbore cavity 1 .

[0176] Specifically, valves are provided on the outlet pipe of the liquid storage tank 2 and the outlet pipe of the sand adding tank 3.

[0177] Preferably, a one-way valve 51 is provided on the liquid inlet pipeline 5 , and the allowed flow direction in the one-way valve 51 is from the hydraulic pump 4 to the simulated wellbore cavity 1 .

[0178] Preferably, a micro-stirrer 8 is provided at the inner bottom end of the simulated wellbore cavity 1, and the micro-stirrer 8 is used to stir the simulated wellbore fluid composed of drilling fluid and cuttings in the simulated wellbore cavity 1, so as to simulate the wellbore fluid movement environment.

[0179] Preferably, a heating wire 9 is provided on the outer wall of the simulated wellbore cavity 1 to achieve temperature control of the simulated wellbore cavity 1 .

[0180] Preferably, the power assembly includes a reciprocating loading cylinder 10 fixedly arranged on the support frame 7, and the piston rod end of the reciprocating loading cylinder 10 is rotationally matched with the turntable 11. Specifically, the piston rod end of the reciprocating loading cylinder 10 is rotationally matched with the turntable 11 through a bearing;

[0181] Two guide rods 12 are vertically fixedly arranged at the bottom end of the rotating disk 11;

[0182] The guide rod 12 and the first pulley 13 are slidably matched in the vertical direction. Specifically, the guide rod 12 and the first pulley 13 are slidably matched in the vertical direction through a linear bearing.

[0183] The lower part of the outer wall of the first pulley 13 is rotatably matched with the support frame 7. Specifically, the lower part of the outer wall of the first pulley 13 is rotatably matched with the support frame 7 through a bearing; the upper part of the outer wall of the first pulley 13 is connected to a driving component used to drive the first pulley 13 to rotate;

[0184] The bottom end of the guide rod 12 is fixedly connected to the connecting plate 16;

[0185] The positioning shaft 14 is fixedly arranged at the bottom end of the connecting plate 16, and the positioning shaft 14 is coaxially arranged with the first pulley 13;

[0186] Preferably, the driving assembly comprises a driving motor 17 fixedly mounted on the supporting frame 7, and the output shaft end of the driving motor 17 is coaxially fixedly connected to the second pulley 18;

[0187] A transmission belt 19 is disposed between an upper portion of an outer side wall of the first pulley 13 and an outer side wall of the second pulley 18 .

[0188] Preferably, the applying assembly comprises two loading cylinders 20 respectively connected to corresponding clamping thrust plates 15;

[0189] The loading cylinder 20 is fixedly arranged on the support frame 7;

[0190] The piston rod of the loading cylinder 20 is fixedly connected to the corresponding clamping thrust plate 15 to control the left and right movement of the corresponding clamping thrust plate 15 .

[0191] Specifically, the piston rod of the loading cylinder 20 is fixedly connected to the corresponding clamping thrust plate 15 via a guide cylinder 21 , and the guide cylinder 21 is slidably matched with the support frame 7 in the left-right direction.

[0192] Preferably, Figure 2 As shown, the clamping thrust plate 15 includes a connecting portion 151 for connecting with the loading cylinder 20, a mounting portion 152 for mounting the external specimen 02, and an adapter plate 153 for connecting the mounting portion 152 and the connecting portion 151;

[0193] The installation portion 152 is located in the simulated wellbore cavity 1 .

[0194] Preferably, the mounting portion 152 is provided with a slot 154 for placing the external sample 02 , and the two slots 154 for clamping the thrust plates 15 are arranged facing each other.

[0195] When in use, the two loading cylinders 20 control the two clamping thrust plates 15 to move toward each other until the outer sample 02 is clamped in the slot 154, and the inner sample 01 passes through the middle through hole of the outer sample 02; when lateral force needs to be applied, the corresponding side loading cylinder 20 applies lateral force to the contact surface between the outer sample 02 and the inner sample 01 through the clamping thrust plate 15 on the corresponding side, so as to simulate the lateral force bearing condition during the friction of the tubing in on-site downhole operations.

[0196] Preferably, the wear measuring mechanism includes a displacement sensor and a weighing instrument for weighing the inner sample 01 and the outer sample 02 before and after the test;

[0197] There are two displacement sensors, which are respectively arranged on two loading cylinders 20, for measuring the distance change value of the corresponding side clamping thrust plate 15 relative to the positioning shaft 14; the sum of the distance change values ​​of the two clamping thrust plates 15 relative to the positioning shaft 14 is used as the wear depth of the sample contact surface.

[0198] Specifically, a torque sensor is provided on the output shaft of the driving motor 17 to test the torque on the output shaft of the driving motor 17, and the torque of the positioning shaft 14 and the inner sample 01 is the same as the torque on the output shaft of the driving motor 17, thereby obtaining the torque of the positioning shaft 14 and the inner sample 01;

[0199] In the present application, the torque sensor is used to measure the torque during the rotational friction of the inner sample 01, and the friction force of the friction surface between the inner sample 01 and the outer sample 02 is obtained by calculation; the calculation formula is: F=M / R, where: F is the friction force, N; M is the measured torque, N·m; R is the radius of the inner sample 01; the calculated friction force is used for the subsequent calculation of the friction coefficient.

[0200] Embodiment 5:

[0201] A method for testing wear of an oil and gas pipe string is implemented using the oil and gas pipe string wear testing device in Example 4, and comprises the following steps:

[0202] Step 11: According to the actual sizes of casing, drill pipe and well wall in the target work area, the sizes of inner sample 01 and outer sample 02 are determined according to the similarity principle, wherein the materials used for inner sample 01 and outer sample 02 are the same as those in the target work area; according to the sizes and materials, the corresponding inner sample 01 and outer sample 02 are prepared and weighed respectively by a weighing instrument to obtain the initial weight of inner sample 01 and the initial weight of outer sample 02;

[0203] Step 12: Determine the test temperature in the simulated wellbore cavity 1 and the amount of sand carried by the fluid entering the simulated wellbore cavity 1 according to the downhole temperature of the target work area, the drilling fluid system, and the particle size of the rock cuttings;

[0204] Step 13: According to the drill pipe rotation speed or the casing running speed, the rotation speed of the inner sample 01 is determined according to the size scaling ratio.

[0205] Step 14: Use Landmark wellplan software to calculate the lateral force on the drill pipe or casing in the target work area, and then determine the lateral contact force of the sample based on the stress similarity principle;

[0206] Step 15: According to the drilling speed of the drill pipe or the casing lifting and lowering speed in the target work area, the up and down reciprocating speed of the inner sample 01 is determined based on the similarity principle;

[0207] Step 16: Determine the inclination angle of the inner hole centerline of the outer sample 02 according to the wellbore trajectory inclination angle in the target work area;

[0208] Step 17: Inject the mixed fluid into the simulated wellbore cavity 1 according to the drilling fluid, cuttings particle size, and sand carrying capacity of the fluid determined in step 12, and turn on the micro-stirrer 8 at the same time; stop injecting the fluid after the mixed fluid in the simulated wellbore cavity 1 reaches a preset height, wherein the height of the mixed fluid needs to immerse the outer sample 02;

[0209] Step 18: Using the heating wire 9, the temperature in the simulated wellbore cavity 1 reaches the test temperature determined in step 12;

[0210] Step 19: The inner sample 01 determined in step 11 is fixedly connected to the positioning shaft 14, and the outer sample 02 determined in step 11 is clamped between two clamping thrust plates 15;

[0211] Step 20: First, the sample contact lateral force determined in step 14 is applied to the contact surface between the inner sample 01 and the outer sample 02 through one of the loading cylinders 20;

[0212] Then, the reciprocating loading cylinder 10 is started to make the internal sample 01 reciprocate up and down at the up and down reciprocating speed determined in step 15;

[0213] Finally, the driving motor 17 is started to rotate the internal sample 01 at the rotation speed determined in step 13;

[0214] The timing starts from the time when the inner sample 01 starts to move, until the friction and wear test reaches the set test time; during this process, the displacement sensor detects the change in the distance between the corresponding side clamping thrust plate 15 and the positioning shaft 14;

[0215] Step 21: After the set test time is reached, the loading cylinder 20, the reciprocating loading cylinder 10 and the driving motor 17 are turned off in sequence;

[0216] Step 22: Stop heating the heating wire 9, remove the one-way valve after the temperature cools down, and drain the sand-carrying mud in the simulated wellbore cavity 1;

[0217] Step 23: Take out the outer sample 02, dismantle the inner sample 01, and weigh the inner sample 01 and the outer sample 02 after the test using a weighing instrument to obtain the final weight of the inner sample 01 and the final weight of the outer sample 02.

[0218] Step 24: The sum of the distance changes between the two clamping thrust plates 15 and the positioning shaft 14 is taken as the wear depth of the contact surface of the sample;

[0219] The difference between the initial weight and the final weight of the internal sample 01 is taken as the wear change of the internal sample 01;

[0220] The difference between the initial weight and the final weight of the external sample 02 is taken as the wear change of the external sample 02.

[0221] The present invention fully considers the wear environment coupled with complex working conditions faced by the casing string during wellbore operations, changes the previous simulation of only a single rotational friction motion form, and realizes the reciprocating-rotational composite friction motion form between the inner sample 01 and the outer sample 02 through the setting of the composite motion mechanism. It can be used to simulate the casing wall wear process under rotation, reciprocating and the composite form of the two, and then can simulate the multi-medium curved surface friction contact of the friction between the drill pipe and the casing, and the friction between the casing and the well wall rock, thereby providing experimental support for the subsequent casing safety evaluation and the safety guarantee of the wellbore throughout the life cycle.

[0222] Embodiment 6:

[0223] A method for testing wear of an oil and gas pipe string, simulating the friction between the outer wall of a drill pipe and the inner wall of a casing during drilling, is implemented using the oil and gas pipe string wear testing device in Example 4, and includes the following steps:

[0224] Step 11: In the drilling design of target area 1, the inner diameter of the three-open casing is 170mm and the outer diameter of the drill pipe is 127mm. According to the similarity principle, the inner diameter of the outer sample 02 and the outer diameter of the inner sample 01 are 56.7mm and 42.3mm respectively. The steel grade of the outer sample 02 is P110, and the steel grade of the inner sample 01 is G105.

[0225] The initial weight of the inner sample 01 and the initial weight of the outer sample 02 obtained by the weighing instrument are 2.34 kg and 3.27 kg respectively;

[0226] The inner sample 01 simulates the drill pipe, and the outer sample 02 simulates the sleeve;

[0227] Step 12: The downhole temperature of the target work area 1 is 82-92°C, the drilling fluid system is an oil-based drilling fluid, and the particle size of the rock cuttings is 0.3-0.5 cm; the test temperature in the simulated wellbore cavity 1 is determined to be 87°C and the sand carrying capacity of the fluid is 0.2 kg / L;

[0228] Step 13: According to the drill pipe rotation speed and the size scaling ratio, the rotation speed of the inner sample 01 is determined to be 60r / min.

[0229] Step 14: Use Landmark wellplan software to calculate the lateral force on the wellbore string in the target work area 1, and obtain 400KN. Then, according to the principle of stress similarity, determine that the lateral contact force of the sample is 27KN;

[0230] Step 15: The default setting for the pure drilling process is that there is no reciprocating friction motion and the reciprocating speed is 0;

[0231] Step 16: Determine that the inclination angle of the inner hole of the outer sample 02 is 2.3° according to the wellbore trajectory inclination angle of 2.3° in the target work area 1;

[0232] Step 17: Inject the mixed fluid into the simulated wellbore cavity 1 according to the sand carrying volume of the fluid of 0.2 kg / L determined in step 12, and turn on the micro-stirrer 8 at the same time; stop injecting the fluid after the mixed fluid in the simulated wellbore cavity 1 reaches a preset height;

[0233] Step 18: Using the heating wire 9, the temperature in the simulated wellbore cavity 1 reaches the test temperature of 87° C. determined in step 12;

[0234] Step 19: The inner sample 01 determined in step 11 is fixedly connected to the positioning shaft 14, and the outer sample 02 determined in step 11 is clamped between two clamping thrust plates 15;

[0235] Step 20: First, a sample contact lateral force of 27 KN determined in step 14 is applied to the contact surface between the inner sample 01 and the outer sample 02 through one of the loading cylinders 20;

[0236] Start the driving motor 17 to rotate the internal sample 01 at a rotation speed of 60 r / min;

[0237] The timing starts from the time when the inner sample 01 starts to move, until the friction and wear test reaches the set test time of 1h; during this process, the displacement sensor detects the change in the distance between the corresponding side clamping thrust plate 15 and the positioning shaft 14;

[0238] In this process, the torque sensor measures the torque, transmits the data to the computer, calculates the friction force, and obtains the curve of friction force changing with the test time, such as Figure 3 As shown;

[0239] Step 21: After reaching the set test time of 1 hour, the loading cylinder 20 and the driving motor 17 are turned off in sequence;

[0240] Step 22: Stop heating the heating wire 9, remove the one-way valve after the temperature cools down, and drain the sand-carrying mud in the simulated wellbore cavity 1;

[0241] Step 23: Take out the outer sample 02, dismantle the inner sample 01, and weigh the inner sample 01 and the outer sample 02 after the test using a weighing instrument. The final weight of the inner sample 01 is 2.34 kg, and the final weight of the outer sample 02 is 2.58 kg.

[0242] Step 24: The sum of the distance changes of the two clamping thrust plates 15 relative to the positioning shaft 14 is 2.76 mm, and this value is used as the wear depth of the inner wall surface of the outer sample 02;

[0243] The difference between the initial weight and the final weight of the internal sample 01 is 0, which is taken as the wear change of the internal sample 01;

[0244] The difference between the initial weight and the final weight of the external sample 02 is 0.69 kg, which is taken as the wear change of the external sample 02.

[0245] Embodiment 7:

[0246] A method for testing wear of an oil and gas pipe string, simulating the friction between the outer wall of the casing and the well wall rock during the casing running process, is implemented using the oil and gas pipe string wear testing device in Example 4, and includes the following steps:

[0247] Step 11: In the drilling design of target area 2, the outer diameter of the four-open casing is 127mm and the well diameter is 168.28mm. According to the principle of similarity, the inner diameter of the outer sample 02 and the outer diameter of the inner sample 01 are 56.1mm and 42.3mm respectively. The outer sample 02 is shale rock mass, and the steel grade of the inner sample 01 is P110;

[0248] The initial weight of the inner sample 01 and the initial weight of the outer sample 02 obtained by the weighing instrument were 2.34 kg and 4.23 kg, respectively.

[0249] The inner sample 01 simulates the casing, and the outer sample 02 simulates the wellbore rock mass;

[0250] Step 12: The downhole temperature of the target work area 2 is 82-92°C, the drilling fluid system is oil-based drilling fluid, and the rock cuttings particle size is 0.3-0.5 cm; the test temperature in the simulated wellbore cavity 1 is determined to be 87°C and the sand carrying capacity of the fluid is 0.05 kg / L;

[0251] Step 13: According to the casing rotation speed and the size scaling ratio, the rotation speed of the inner sample 01 is determined to be 30 r / min.

[0252] Step 14: Use Landmark wellplan software to calculate the lateral force on the wellbore string in the target work area 2, and obtain 620KN. Then, according to the principle of stress similarity, determine that the lateral contact force of the sample is 31KN;

[0253] Step 15: According to the casing lifting and lowering speed, determine the reciprocating speed of the inner sample 01 to be 0.5m / s;

[0254] Step 16: According to the wellbore trajectory inclination angle of 4° in the target work area 2, determine that the inclination angle of the inner hole of the outer sample 02 is 4°;

[0255] Step 17: Inject the mixed fluid into the simulated wellbore cavity 1 according to the sand carrying volume of the fluid of 0.05 kg / L determined in step 12, and turn on the micro-stirrer 8 at the same time; stop injecting the fluid after the mixed fluid in the simulated wellbore cavity 1 reaches a preset height;

[0256] Step 18: Using the heating wire 9, the temperature in the simulated wellbore cavity 1 reaches the test temperature of 87° C. determined in step 12;

[0257] Step 19: The inner sample 01 determined in step 11 is fixedly connected to the positioning shaft 14, and the outer sample 02 determined in step 11 is clamped between two clamping thrust plates 15;

[0258] Step 20: First, the sample contact lateral force of 31 KN determined in step 14 is applied to the contact surface between the inner sample 01 and the outer sample 02 through one of the loading cylinders 20;

[0259] Start the reciprocating loading cylinder 10 to make the internal sample 01 reciprocate up and down at a speed of 0.5 m / s;

[0260] Start the driving motor 17 to rotate the internal sample 01 at a rotation speed of 30 r / min;

[0261] The timing starts from the time when the inner sample 01 starts to move, until the friction and wear test reaches the set test time of 15 minutes; during this process, the displacement sensor detects the change in the distance between the corresponding side clamping thrust plate 15 and the positioning shaft 14;

[0262] In this process, the torque sensor measures the torque, transmits the data to the computer, calculates the friction force, and obtains the curve of friction force changing with the test time, such as Figure 4 As shown;

[0263] Step 21: After the set test time of 10 minutes is reached, the loading cylinder 20, the reciprocating loading cylinder 10, and the driving motor 17 are closed in sequence;

[0264] Step 22: Stop heating the heating wire 9, remove the one-way valve after the temperature cools down, and drain the sand-carrying mud in the simulated wellbore cavity 1;

[0265] Step 23: Take out the outer sample 02, remove the inner sample 01, and weigh the inner sample 01 and the outer sample 02 after the test using a weighing instrument, and obtain a final weight of 2.07 kg for the inner sample 01 and a final weight of 4.23 kg for the outer sample 02;

[0266] Step 24: The sum of the distance changes of the two clamping thrust plates 15 relative to the positioning shaft 14 is 1.3 mm, and this value is used as the wear depth of the outer wall of the inner sample 01;

[0267] The difference between the initial weight and the final weight of the inner sample 01 is 0.27 kg, which is taken as the wear change of the inner sample 01;

[0268] The difference between the initial weight and the final weight of the external sample 02 is 0, which is taken as the wear change of the external sample 02.

[0269] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not a limitation of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the protection scope of the present invention.

Claims

1. An oil and gas pipe wear testing device, characterized in that: The invention comprises a support base, on which a simulated wellbore assembly for simulating the physical environment of the wellbore is arranged, a compound motion mechanism for driving the inner sample to perform up and down reciprocating motion or rotational motion or up and down reciprocating and rotational compound motion, a contact load applying mechanism for clamping the outer sample and applying lateral force to the contact surface between the outer sample and the inner sample, and a wear measuring mechanism for measuring the wear amount of the inner sample or the outer sample; The simulated wellbore assembly comprises a simulated wellbore cavity fixedly arranged on a support seat, and the simulated wellbore cavity is connected to a fluid supply mechanism for providing simulated wellbore fluid; The composite motion mechanism comprises a positioning shaft for mounting the internal sample and a power assembly for driving the positioning shaft to move, wherein the positioning shaft is located at the upper part of the simulated wellbore cavity; The contact load applying mechanism comprises two symmetrical clamping thrust plates for clamping the external sample and an applying assembly for providing clamping force and lateral force. The part of the clamping thrust plate for clamping the external sample is located in the simulated wellbore cavity.

2. The oil and gas pipe wear testing device according to claim 1, characterized in that: The support seat comprises a transparent cover, and a support frame is arranged on the top of the transparent cover; The top of the simulated wellbore cavity is fixedly connected to the bottom end of the top plate of the transparent cover, and a through hole matching the wellhead of the simulated wellbore cavity is arranged on the top plate of the transparent cover.

3. The oil and gas pipe wear testing device according to claim 1, characterized in that: The fluid supply mechanism includes a liquid storage tank for storing drilling fluid and a sand adding tank for storing rock cuttings; The outlet pipe of the liquid storage tank and the outlet pipe of the sand adding tank are connected to the inlet pipe of the hydraulic pump after being collected; The outlet pipe of the hydraulic pump is connected to one end of a liquid inlet pipeline, and the other end of the liquid inlet pipeline is connected to the bottom inlet of the simulated wellbore cavity.

4. The oil and gas pipe wear testing device according to claim 3, characterized in that: A one-way valve is arranged on the liquid inlet pipeline, and the flow direction allowed in the one-way valve is from the hydraulic pump to the simulated wellbore cavity.

5. The oil and gas pipe wear testing device according to claim 1, characterized in that: A micro stirrer is arranged at the inner bottom end of the simulated wellbore cavity.

6. The oil and gas pipe wear testing device according to claim 1, characterized in that: A heating wire is arranged on the outer wall of the simulated wellbore cavity.

7. The oil and gas pipe wear testing device according to claim 2, characterized in that: The power assembly comprises a reciprocating loading cylinder fixedly arranged on a support frame, and the piston rod end of the reciprocating loading cylinder is rotationally matched with the turntable; Two guide rods are vertically fixed at the bottom end of the turntable; The guide rod and the first pulley are slidably matched in the vertical direction; The lower part of the outer wall of the first pulley is rotatably matched with the support frame; the upper part of the outer wall of the first pulley is connected to a driving component used to drive the first pulley to rotate; The bottom end of the guide rod is fixedly connected to the connecting plate; The positioning shaft is fixedly arranged at the bottom end of the connecting plate, and the positioning shaft is coaxially arranged with the first pulley.

8. The oil and gas pipe string wear testing device according to claim 7, characterized in that: The driving assembly comprises a driving motor fixedly arranged on a supporting frame, and the output shaft end of the driving motor is coaxially fixedly connected with the second pulley; A transmission belt is arranged between the upper portion of the outer side wall of the first pulley and the outer side wall of the second pulley.

9. The oil and gas pipe wear testing device according to claim 8, characterized in that: The applying assembly includes two loading cylinders respectively connected to corresponding clamping thrust plates; The loading cylinder is fixedly arranged on the supporting frame; The piston rod of the loading cylinder is fixedly connected to the corresponding clamping thrust plate.

10. The oil and gas pipe string wear testing device according to claim 9, characterized in that: The clamping thrust plate includes a connecting portion for connecting to the loading cylinder, a mounting portion for mounting the external specimen, and an adapter plate for connecting the mounting portion and the connecting portion; The installation portion is located in the simulated wellbore cavity.

11. The oil and gas pipe string wear testing device according to claim 10, characterized in that: The mounting portion is provided with a slot for placing an external sample, and two slots for clamping thrust plates are arranged facing each other.

12. The oil and gas pipe string wear testing device according to claim 1, characterized in that: The wear measuring mechanism includes a displacement sensor and a weighing instrument for weighing the inner sample and the outer sample before and after the test; There are two displacement sensors, which are respectively arranged on two loading cylinders.

13. A method for testing wear of oil and gas pipes, characterized in that: The oil and gas pipe wear test device according to any one of claims 1 to 12 is used for implementation, comprising the following steps: Step 11: According to the actual sizes of casing, drill pipe and well wall in the target work area, the sizes of the inner sample and the outer sample are determined according to the similarity principle, wherein the materials used for the inner sample and the outer sample are the same as those in the target work area; the corresponding inner sample and the outer sample are prepared according to the size and material and weighed respectively by a weighing instrument to obtain the initial weight of the inner sample and the initial weight of the outer sample; Step 12: Determine the test temperature in the simulated wellbore cavity and the amount of sand carried by the fluid entering the simulated wellbore cavity according to the downhole temperature of the target work area, the drilling fluid system, and the particle size of the rock cuttings; Step 13: Determine the rotation speed of the inner sample according to the drilling pipe rotation speed or the casing running rotation speed and the size scaling ratio. Step 14: Use Landmark wellplan software to calculate the lateral force on the drill pipe or casing in the target work area, and then determine the lateral contact force of the sample based on the stress similarity principle; Step 15: According to the drilling speed of the drill pipe or the lifting and lowering speed of the casing in the target work area, the up and down reciprocating speed of the internal sample is determined based on the similarity principle; Step 16: Determine the inclination angle of the inner hole centerline of the outer sample according to the wellbore trajectory inclination angle in the target work area; Step 17: Inject the mixed fluid into the simulated wellbore cavity according to the drilling fluid, cuttings particle size, and sand carrying capacity of the fluid determined in step 12, and turn on the micro-agitator at the same time; Step 18: Using the heating wire, the temperature in the simulated wellbore cavity reaches the test temperature determined in step 12; Step 19: The inner sample determined in step 11 is fixedly connected to the positioning shaft, and the outer sample determined in step 11 is clamped between two clamping thrust plates; Step 20: First, applying the sample contact lateral force determined in step 14 to the contact surface between the inner sample and the outer sample through one of the loading cylinders; Then start the reciprocating loading cylinder to make the internal sample reciprocate up and down at the up and down reciprocating speed determined in step 15; Finally, the driving motor is started to rotate the internal sample at the rotation speed determined in step 13; The timing starts from the time when the inner sample starts to move until the friction and wear test reaches the set test time; during this process, the displacement sensor detects the change in the distance between the corresponding side clamping thrust plate and the positioning axis; Step 21: After the set test time is reached, the loading cylinder, the reciprocating loading cylinder and the driving motor are turned off in sequence; Step 22: Stop heating the heating wire, remove the one-way valve after the temperature cools down, and drain the sand-carrying mud in the simulated wellbore cavity; Step 23: Take out the outer sample, dismantle the inner sample, and weigh the inner sample and the outer sample after the test using a weighing instrument to obtain the final weight of the inner sample and the final weight of the outer sample. Step 24: The sum of the distance changes between the two clamping thrust plates and the positioning axis is taken as the wear depth of the contact surface of the specimen; The difference between the initial weight and the final weight of the internal sample is taken as the wear change of the internal sample; The difference between the initial weight and the final weight of the external specimen is taken as the wear change of the external specimen.

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