Tubular column deformation testing device and method under simulated internal pressure and external load composite working condition

Abstract

The invention discloses a tubular column deformation testing device for simulating an internal pressure and external load composite working condition. The tubular column deformation testing device comprises a tubular column clamp, a loading assembly, a deformation detection piece and a pressurizing assembly, the tubular column clamp comprises a supporting table. Two clamping supports are arranged on the supporting table; the loading assembly comprises two lower fixing seats and an upper fixing seat; the top of the lower fixing base is connected with a lower pressing head cutter. The bottom of the upper fixing base is connected with an upper pressing head cutter. The top end of the upper fixing seat is connected with a piston rod of the loading oil cylinder. The invention further discloses a tubular column deformation test method under the simulated curved surface external load working condition, a tubular column deformation test method under the simulated internal pressure and curved surface external load composite working condition, a tubular column deformation test method under the simulated internal pressure and shear load composite working condition and a tubular column deformation test method under the simulated internal pressure and bending load composite working condition. The testing device disclosed by the invention can be used for carrying out deformation test on the tubular column sample under the working condition of coexistence of external loads in various forms of internal pressure, shearing and bending.

Description

Technical Field

[0001] The invention belongs to the technical field of well cementing and completion design in the field of petroleum exploration, and in particular relates to a pipe string deformation testing device and method under a composite working condition of simulated internal pressure and external load. Background Art

[0002] In the process of shale gas exploitation, horizontal wells and large-scale volume fracturing are the key technologies for its successful development. During the fracturing of shale gas horizontal wells, the casing string will be subjected to multiple frequencies of severe internal pressure cycle loads and external squeeze loads, which will cause the casing string strength to yield and fail, resulting in small plastic deformation; in addition, the casing string may be subjected to shear stress loads caused by faults and cracks during the multi-stage fracturing process, resulting in shear deformation. That is, the force loads on the casing string of shale gas wells include internal pressure and external loads in various forms of shear and bending. Under the combined working conditions of internal pressure and external loads, the casing string will yield and fail to deform, threatening the integrity of the wellbore and causing adverse effects on production safety.

[0003] Therefore, it is very necessary to conduct deformation tests of the tubing under various load forms to evaluate the strength of the tubing before running the tubing string. The deformation test of the tubing string can provide a basis for failure judgment and deformation prediction of the casing string under multi-stage fracturing.

[0004] At present, the devices and methods for casing string deformation testing are mostly aimed at the stress scenarios of the strings during conventional oil and gas development, ignoring the coexistence of casing circulating internal pressure and various forms of external loads such as shear and bending during shale gas well fracturing.

[0005] Based on the above problems, the present application proposes a device and method for testing pipe deformation under conditions simulating combined internal pressure and external loads, which is capable of performing pipe deformation testing under conditions where internal pressure and various forms of external loads, such as shear and bending, coexist. Summary of the invention

[0006] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide a pipe string deformation testing device under a combined working condition of simulated internal pressure and external load.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] A pipe string deformation testing device under a combined working condition of simulated internal pressure and external load, comprising a pipe string clamp for clamping a pipe string sample, a loading assembly for applying an external load to the pipe string sample, a deformation detection member for detecting the deformation amount of the pipe string sample, and a pressurizing assembly for applying internal pressure to the pipe string sample;

[0009] The pipe column clamp comprises a support platform;

[0010] The support platform is provided with two parallel clamping supports capable of clamping pipe column samples of different lengths;

[0011] The loading assembly includes two lower fixing seats and an upper fixing seat;

[0012] The top of the lower fixing seat is detachably connected with a lower pressure head tool, and the lower fixing seat is arranged on the support platform and can move along the axial direction of the pipe column sample;

[0013] An upper pressure head tool is detachably connected to the bottom of the upper fixing seat, and the upper fixing seat is located on the upper part of the lower fixing seat;

[0014] The end surfaces where the lower pressure head tool and the upper pressure head tool are in contact with the pipe string sample are cylindrical in structure;

[0015] The top end of the upper fixing seat is fixedly connected to the bottom end of the piston rod of the loading cylinder, and the loading cylinder is fixedly arranged on the supporting platform.

[0016] Preferably, support plates are vertically fixedly arranged at the left and right ends of the support platform;

[0017] A guide rod is vertically fixed between the two support plates;

[0018] The clamping support is slidably matched with the guide rod.

[0019] Preferably, a clamping cylinder is provided at each of the ends of the two support plates facing away from each other;

[0020] The piston rod end of the clamping oil cylinder passes through the corresponding support plate and is fixedly connected to the corresponding clamping support.

[0021] Preferably, an adjustment cylinder is provided at each of the ends of the two support plates facing away from each other;

[0022] The piston rod end of the adjusting oil cylinder passes through the corresponding supporting plate and is fixedly connected to the corresponding lower fixing seat.

[0023] Preferably, four supporting columns are fixed vertically upward on the top of the support platform;

[0024] An upper crossbeam is fixedly arranged on the top of the load-bearing column;

[0025] The loading cylinder is fixedly arranged on the upper cross beam.

[0026] Preferably, a load sensor is arranged between the upper fixing seat and the piston rod of the loading cylinder.

[0027] Preferably, the pressurizing component comprises a water pressure pump station, and the outlet of the water pressure pump station is connected to a water supply pipe;

[0028] Sealing covers are arranged at both ends of the pipe column sample, and one of the sealing covers is provided with a water injection port which is connected to the interior of the pipe column sample and can be connected to a water supply pipe.

[0029] Preferably, the deformation detection member is an outer wall clamping distance meter used to measure the change in the outer diameter of the pipe string sample;

[0030] The outer wall clamping distance meter comprises a deformation measuring sensor 1, a hook, and a deformation line 1 extending in the vertical direction and arranged between the deformation measuring sensor 1 and the hook; the deformation line 1 is located on the vertical center plane in the left-right direction of the upper fixing seat;

[0031] The deformation measurement sensor 1 is fixedly arranged on the front end surface of the upper fixing seat;

[0032] The hook is fixedly arranged on one of the lower fixing seats.

[0033] Preferably, the deformation detection member is an inner wall multi-arm rangefinder for measuring the change in the inner diameter of the pipe string sample;

[0034] The inner wall multi-arm rangefinder comprises a support base, on which a support guide column extending vertically upward is fixedly arranged;

[0035] The support guide column is provided with a first arm extending in the horizontal direction, and the position of the first arm in the vertical direction of the support guide column is adjustable;

[0036] A second arm extending in the horizontal direction is arranged on the support guide column at the upper part of the first arm, and the second arm is slidably matched with the support guide column in the vertical direction;

[0037] A spring support plate is arranged on the support guide column between the first arm and the second arm, and a spring capable of pressing toward the second arm is fixedly arranged on the upper part of the spring support plate;

[0038] A bull's eye bearing is provided on the bottom side of the end of the first arm away from the supporting guide column and on the top side of the end of the second arm away from the supporting guide column;

[0039] A second deformation line extending in a vertical direction is arranged between the first arm and the second arm, and a second deformation measuring sensor for detecting a deformation amount of the second deformation line is arranged on the second arm.

[0040] The invention also discloses a method for testing pipe column deformation under a simulated curved surface external load condition.

[0041] The pipe string deformation test method under the condition of simulating curved surface external load is implemented by using a pipe string deformation test device under the condition of simulating internal pressure and external load, and includes the following steps:

[0042] Step 11: Determine the lower pressure head tool and the upper pressure head tool that match the pipe string sample to be tested;

[0043] Step 12: Select a tool having a set curved surface angle from the lower punch tool and the lower punch tool determined in step 11;

[0044] Step 13: Install the lower pressure head tool selected in step 12 on one of the lower fixed seats, and install the upper pressure head tool selected in step 12 on the upper fixed seat;

[0045] Step 14: Align the lower pressure head tool and the upper pressure head tool up and down by adjusting the oil cylinder accordingly;

[0046] Step 15: Place the middle of the pipe sample on the lower pressure head tool;

[0047] Step 16: Install an inner wall multi-arm distance meter on the pipe string sample for measuring the change of the outer diameter of the pipe string sample;

[0048] Step 17: The loading cylinder controls the upper pressure head tool to move downward until it contacts the surface of the pipe string sample;

[0049] Step 18: The loading cylinder controls the lower pressure head tool to move downward at a set speed to apply pressure to the pipe string sample until the pipe string sample yields;

[0050] In this process, the load sensor detects the test pressure applied by the loading cylinder to the pipe sample, and the inner wall multi-arm distance meter measures the change in the inner diameter of the pipe sample;

[0051] The data monitored by the load sensor and the inner wall multi-arm distance meter are transmitted to the computer to obtain the relationship curve between the load test pressure and the change in inner diameter of the curved surface of the pipe string sample.

[0052] The invention also discloses a pipe column deformation testing method under a composite working condition of simulating internal pressure and curved surface external load.

[0053] The pipe string deformation test method under the combined working condition of simulating internal pressure and curved surface external load is implemented by using a pipe string deformation test device under the combined working condition of simulating internal pressure and external load, and includes the following steps:

[0054] Step 21: Determine the lower pressure head tool and the upper pressure head tool that match the pipe string sample to be tested;

[0055] Step 22: Install the lower pressure head tool selected in step 21 on one of the lower fixed seats, and install the upper pressure head tool selected in step 21 on the upper fixed seat;

[0056] Step 23: Align the lower pressure head tool and the upper pressure head tool up and down by adjusting the oil cylinder accordingly;

[0057] Step 24: Place the middle of the pipe string sample on the lower pressure head tool, install sealing covers on both ends of the pipe string sample, and then adjust the positions of the two clamping supports through two clamping cylinders to clamp the pipe string sample;

[0058] Step 25: Installing an outer wall clamping distance meter on the pipe string sample for measuring the change of the outer diameter of the pipe string sample;

[0059] Step 26: Connect the water supply pipe to the water injection port of one of the sealing covers, and inject water into the pipe string sample through the hydraulic pump station to increase the pressure, so that the hydraulic load value in the pipe string sample reaches the set internal pressure value;

[0060] Step 27: The loading cylinder controls the upper pressure head tool to move downward until it contacts the surface of the pipe string sample;

[0061] Step 28: The loading cylinder controls the lower pressure head tool to move downward to reach the set maximum force value of the external extrusion load;

[0062] In this process, the load sensor detects the external squeeze load value applied by the loading cylinder to the pipe sample, and the outer wall clamping distance meter measures the change in the outer diameter of the pipe sample;

[0063] The data monitored by the load sensor and the outer wall clamping distance meter are transmitted to the computer to obtain the relationship curve between the internal pressure of the pipe string sample and the external load value-outer diameter change under the composite working condition of the curved surface external load.

[0064] The invention also discloses a method for testing pipe column deformation under a composite working condition of simulated internal pressure and shear load.

[0065] The pipe string deformation test method under the combined working condition of simulated internal pressure and shear load is implemented by using a pipe string deformation test device under the combined working condition of simulated internal pressure and external load, and includes the following steps:

[0066] Step 31: Determine a lower pressure head tool and an upper pressure head tool that match the pipe string sample to be tested;

[0067] Step 32: Install the lower pressure head tool selected in step 31 on one of the lower fixed seats, and install the upper pressure head tool selected in step 31 on the upper fixed seat;

[0068] Step 33: Adjust the oil cylinder accordingly so that the distance between the lower pressure head tool and the upper pressure head tool reaches the set offset distance;

[0069] Step 34: Place the pipe string sample on the lower pressure head tool, and make the upper pressure head tool located in the middle of the pipe string sample; install sealing covers at both ends of the pipe string sample, and then adjust the positions of the two clamping supports through two clamping cylinders to clamp the pipe string sample;

[0070] Step 35: Installing an outer wall clamping distance meter on the pipe string sample for measuring the change of the inner diameter of the pipe string sample;

[0071] Step 36: Connect the water supply pipe to the water injection port of one of the sealing covers, and inject water into the pipe string sample through the hydraulic pump station to increase the pressure, so that the hydraulic load value in the pipe string sample reaches the set internal pressure value;

[0072] Step 37: The loading cylinder controls the upper pressure head tool to move downward until it contacts the surface of the pipe string sample;

[0073] Step 38: The loading cylinder controls the lower pressure head tool to move downward to reach the set maximum shear load;

[0074] In this process, the load sensor detects the shear load value applied by the loading cylinder to the pipe sample, and the outer wall clamping distance meter measures the change in the outer diameter of the pipe sample;

[0075] The data monitored by the load sensor and the outer wall clamping distance meter are transmitted to the computer to obtain the relationship curve between the shear load value and the outer diameter change under the combined working condition of the internal pressure and shear load of the pipe string sample.

[0076] The invention also discloses a pipe column deformation testing method under a composite working condition of simulated internal pressure and bending load.

[0077] The pipe string deformation test method under the combined working condition of simulating internal pressure and bending load is implemented by using a pipe string deformation test device under the combined working condition of simulating internal pressure and external load, and includes the following steps:

[0078] Step 41: Determine a lower pressure head tool and an upper pressure head tool that match the pipe string sample to be tested;

[0079] Step 42: Install the lower pressure head tool selected in step 41 on the two lower fixed seats respectively, and install the upper pressure head tool selected in step 41 on the upper fixed seat;

[0080] Step 43: The two lower pressure head tools are symmetrically distributed on both sides of the upper pressure head tool by adjusting the oil cylinder accordingly, and the distance between the two lower pressure head tools reaches the set tool spacing;

[0081] Step 44: placing the pipe string sample on the lower pressure head tool, and making the upper pressure head tool be located in the middle of the pipe string sample; installing sealing covers at both ends of the pipe string sample, and then adjusting the positions of the two clamping supports by two clamping cylinders so as to clamp the pipe string sample;

[0082] Step 45: Installing an outer wall clamping distance meter on the pipe string sample for measuring the change of the inner diameter of the pipe string sample;

[0083] Step 46: Connect the water supply pipe to the water injection port of one of the sealing covers, and inject water into the pipe string sample through the hydraulic pump station to increase the pressure, so that the hydraulic load value in the pipe string sample reaches the set internal pressure value;

[0084] Step 47: The loading cylinder controls the upper pressure head tool to move downward until it contacts the surface of the pipe string sample;

[0085] Step 48: The loading cylinder controls the lower pressure head tool to move downward to reach the set maximum bending load;

[0086] In this process, the load sensor detects the bending load value applied by the loading cylinder to the pipe sample, and the outer wall clamping distance meter measures the change in the outer diameter of the pipe sample;

[0087] The data monitored by the load sensor and the outer wall clamping distance meter are transmitted to the computer to obtain the relationship curve between the internal pressure of the pipe string sample and the bending load value-outer diameter change under the combined working condition of the bending load.

[0088] The beneficial effects of the present invention are:

[0089] The testing device of the present invention can perform deformation tests on tubing samples under conditions where internal pressure, shear and bending and other forms of external loads coexist. The test results and rules can be used to subsequently evaluate and predict the reliability and safe service life of the tubing on site, thereby providing a theoretical basis and experimental support for the development of wellbore integrity safety assurance technology during shale gas well development. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] 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.

[0091] Figure 1 It is a schematic diagram of the structure of a pipe string deformation testing device under a combined working condition of simulating internal pressure and external load of the present invention;

[0092] Figure 2 It is a structural schematic diagram of the pipe column clamp and the loading assembly in the present invention;

[0093] Figure 3 3 is a schematic diagram of the structure of a pipe string deformation testing device under a combined working condition of simulating internal pressure and external load in Example 3 of the present invention;

[0094] Figure 4 Schematic diagram of the curved surface angles of the upper pressure head tool and the lower pressure head tool in the present invention;

[0095] Figure 5 is a curve diagram showing the relationship between the test pressure and the change in outer diameter of the curved surface of the pipe string sample when the curved surface angle of the lower pressure head tool and the upper pressure head tool is 120° in Example 4 of the present invention;

[0096] Figure 6 is a curve diagram showing the relationship between the test pressure and the change in outer diameter of the curved surface of the pipe string sample when the curved surface angle of the lower pressure head tool and the upper pressure head tool is 140° in Example 5 of the present invention;

[0097] Figure 7 is a schematic structural diagram of a pipe string deformation testing device under a combined working condition of simulating internal pressure and external load in Example 6 of the present invention;

[0098] Figure 8 is a curve diagram showing the relationship between the internal pressure of the pipe string sample and the external load value-outer diameter change under the composite working condition of the curved surface external load in Example 7;

[0099] Fig. 9 : is a schematic structural diagram of a pipe string deformation testing device under a combined working condition of simulating internal pressure and external load in Example 8 of the present invention;

[0100] Fig.10 is a curve diagram showing the relationship between the shear load value and the inner diameter change under the combined working condition of the internal pressure and shear load of the pipe string sample in Example 9 of the present invention;

[0101] Fig.11 1 is a schematic diagram of the structure of a pipe string deformation testing device under a combined working condition of simulating internal pressure and external load in Example 10 of the present invention;

[0102] Fig.12 is a curve diagram showing the relationship between the internal pressure of the pipe column sample and the bending load value-inner diameter change under the bending load composite working condition in Example 11 of the present invention;

[0103] Fig.13 It is a structural schematic diagram of the outer wall clamping distance meter in the present invention;

[0104] Fig.14 It is a structural schematic diagram of the inner wall multi-arm rangefinder in the present invention;

[0105] in:

[0106] 0- column sample;

[0107] 1- Support table;

[0108] 101-support plate;

[0109] 102-guide rod;

[0110] 103-clamping cylinder;

[0111] 104- base;

[0112] 105-adjust the oil cylinder;

[0113] 106- load bearing column;

[0114] 107-upper beam;

[0115] 2- Clamping support;

[0116] 3-Lower fixing seat;

[0117] 4-lower pressure head tool;

[0118] 5-Loading cylinder;

[0119] 6-upper fixed seat;

[0120] 7- Upper pressure head tool;

[0121] 8- Load sensor;

[0122] 9- Water pressure pump station;

[0123] 901-Water supply pipe.

[0124] 10- Sealing cover;

[0125] 1001-Water injection port;

[0126] 11-Outer wall clamping distance meter;

[0127] 1101- deformation measurement sensor 1; 1102- deformation line 1; 1103- hook;

[0128] 12-inner wall multi-arm rangefinder; 1201-support base; 1202-support guide column; 1203-first arm; 1204-second arm; 1205-spring support plate; 1206-spring; 1207-bull's eye bearing; 1208-deformation line 2; 1209-deformation measurement sensor 2. DETAILED DESCRIPTION

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0134] Embodiment 1:

[0135] like Figure 1-2 As shown, a pipe string deformation testing device under a combined working condition of simulated internal pressure and external load comprises a pipe string clamp for clamping a pipe string sample 0, a loading assembly for applying an external load to the pipe string sample 0, a deformation detection member for detecting the deformation amount of the pipe string sample 0, and a pressurizing assembly for applying internal pressure to the pipe string sample 0;

[0136] The pipe column clamp comprises a support platform 1; specifically, a base 104 is provided at the bottom of the support platform 1;

[0137] The support platform 1 is provided with two parallel clamping supports 2 capable of clamping pipe column samples 0 of different lengths;

[0138] The loading assembly includes two lower fixing seats 3 and an upper fixing seat 6;

[0139] The top of the lower fixing seat 3 is detachably connected with a lower pressure head tool 4, and the lower fixing seat 6 is arranged on the support platform 1 and can move along the axial direction of the pipe column sample 0;

[0140] An upper pressure head tool 7 is detachably connected to the bottom of the upper fixing seat 6, and the upper fixing seat 6 is located on the upper part of the lower fixing seat 3;

[0141] The end surfaces where the lower pressure head tool 4 and the upper pressure head tool 7 are in contact with the pipe string sample 0 are cylindrical structures, which are used to simulate the curved surface ground stress load conditions of the pipe string in the real environment;

[0142] The top end of the upper fixing seat 6 is fixedly connected to the bottom end of the piston rod of the loading cylinder 5 , and the loading cylinder 5 is fixedly arranged on the supporting platform 1 .

[0143] Preferably, support plates 101 are vertically fixedly arranged at the left and right ends of the support platform 1;

[0144] A guide rod 102 is vertically fixed between the two support plates 101;

[0145] The clamping support 2 is in sliding cooperation with the guide rod 102 .

[0146] Specifically, four guide rods 102 distributed in a rectangular shape are vertically fixed between the two support plates 101;

[0147] The clamping support 2 is in sliding cooperation with the four guide rods 102 .

[0148] Preferably, each of the two support plates 101 facing away from each other is provided with a clamping cylinder 103;

[0149] The piston rod end of the clamping oil cylinder 103 passes through the corresponding support plate 101 and is fixedly connected to the corresponding clamping support 2 .

[0150] The left clamping support 2 is slidable along the guide rod 102 by the left clamping cylinder 103, and the right clamping support 2 is slidable along the guide rod 102 by the right clamping cylinder 103, so that the distance between the two clamping supports 2 can be adjusted, thereby achieving the clamping of pipe samples 0 of different lengths.

[0151] Preferably, an adjustment cylinder 105 is provided at each of the two back-facing ends of the two support plates 101;

[0152] The piston rod end of the adjustment oil cylinder 105 passes through the corresponding support plate 101 and is fixedly connected to the corresponding lower fixing seat 3 .

[0153] The left adjustment cylinder 105 realizes the position adjustment of the left lower fixing seat 3, and the right adjustment cylinder 105 realizes the position adjustment of the right lower fixing seat 3, thereby realizing the adjustment of the vertical distance between the lower pressure head tool 4 and the upper pressure head tool 7.

[0154] Preferably, four supporting columns 106 are fixedly arranged vertically upward on the top of the support platform 1;

[0155] An upper crossbeam 107 is fixedly disposed on the top of the supporting column 106;

[0156] The loading cylinder 5 is fixedly arranged on the upper cross beam 107 .

[0157] Preferably, a load sensor 8 is provided between the upper fixing seat 6 and the piston rod of the loading cylinder 5 .

[0158] Preferably, the pressurizing component comprises a water pressure pump station 9, and the outlet of the water pressure pump station 9 is connected to a water supply pipe 901;

[0159] Sealing covers 10 are provided at both ends of the pipe column sample 0 , and one of the sealing covers 10 is provided with a water injection port 1001 which is connected to the interior of the pipe column sample 0 and can be connected to the water supply pipe 901 .

[0160] The water supply pipe 901 is connected to the water injection port 1001 to realize the internal water supply pressurization of the pipe column sample 0.

[0161] Preferably, the deformation detection member is an outer wall clamping distance meter 11 for measuring the change of the outer diameter of the pipe column sample 0;

[0162] like Fig.13 As shown, the outer wall clamping distance meter 11 includes a deformation measurement sensor 1101, a hook 1103, and a deformation line 1102 extending in the vertical direction between the deformation measurement sensor 1101 and the hook 1103; the deformation line 1102 is located on the vertical center plane in the left-right direction of the upper fixing seat 6;

[0163] The deformation measurement sensor 1101 is fixedly arranged on the front end surface of the upper fixing seat 6, and is used to detect the deformation amount of the deformation line 1102;

[0164] The hook 1103 is fixedly disposed on one of the lower fixing seats 3 .

[0165] When in use, after the lower pressure head tool 4 and the upper pressure head tool 7 contact the pipe column sample 0, the deformation line 1102 is hung on the hook 1103; when the pipe column sample 0 is squeezed and deformed, the deformation line 1102 will follow the deformation of the pipe column sample 0 and produce vertical deformation, and the deformation will be reflected in the deformation measurement sensor 1101 through the deformation line 1102, thereby measuring the change in the outer diameter of the pipe column sample 0.

[0166] Specifically, in the present application, the clamping cylinder 103, the adjusting cylinder 105, and the loading cylinder 5 are all connected to the hydraulic oil station, wherein the connection between the clamping cylinder 103, the adjusting cylinder 105, and the loading cylinder 5 and the hydraulic oil station are all prior arts, and the specific connection method will not be repeated here.

[0167] Embodiment 2:

[0168] Different from the embodiment 1, the deformation detection member is an inner wall multi-arm distance meter 12 for measuring the change of the inner diameter of the pipe column sample 0.

[0169] like Fig.14 As shown, the inner wall multi-arm rangefinder 12 includes a support base 1201, and a support guide column 1202 extending vertically upward is fixedly arranged on the support base 1201;

[0170] The support guide column 1202 is provided with a first arm 1203 extending in the horizontal direction, and the position of the first arm 1203 in the vertical direction of the support guide column 1202 is adjustable;

[0171] A second arm 1204 extending in the horizontal direction is provided on the support guide column 1202 at the upper part of the first arm 1203, and the second arm 1204 and the support guide column 1202 are slidably matched in the vertical direction; specifically, the second arm 1204 and the support guide column 1202 are slidably matched in the vertical direction through a linear bearing;

[0172] A spring support plate 1205 is provided on the support guide column 1202 between the first arm 1203 and the second arm 1204, and a spring 1206 capable of pressing against the second arm 1204 is fixedly provided on the upper portion of the spring support plate 1205;

[0173] The bottom side of the end of the first arm 1203 away from the support guide column 1202 and the top side of the end of the second arm 1204 away from the support guide column 1202 are both provided with a bull's eye bearing 1207;

[0174] A second deformation line 1208 extending in the vertical direction is arranged between the first arm 1203 and the second arm 1204 , and a second deformation measuring sensor 1209 for detecting the deformation amount of the second deformation line 1208 is arranged on the second arm 1204 .

[0175] Before the test, adjust the position of the first arm 1203 on the support guide column 1202 so that the bull's eye bearing on the first arm 1203 contacts the lower inner wall of the pipe column sample 0, and the bull's eye bearing on the second arm 1204 contacts the upper inner wall of the pipe column sample 0 under the action of the spring 1206, and the position where the bull's eye bearing contacts the inner wall of the pipe column sample 0 is located on the vertical center plane in the left and right directions of the upper fixed seat 6.

[0176] When the tubular sample 0 is squeezed and deformed, the bull's eye bearing on the second arm 1204 will change its vertical position following the deformation of the tubular sample 0. This change will be reflected in the deformation measurement sensor 1209 through the deformation line 1102, thereby measuring the change in the inner diameter of the tubular sample 0.

[0177] Its technical features are the same as those in Example 1.

[0178] Embodiment 3:

[0179] The method for testing the deformation of a pipe string under a simulated curved surface external load condition is implemented using the pipe string deformation testing device under a simulated internal pressure and external load combined condition in Example 2, and includes the following steps:

[0180] Step 11: Determine the lower pressure head tool 4 and the upper pressure head tool 7 that match the pipe string sample 0 to be tested;

[0181] Step 12: Select a tool with a set curved surface angle from the lower pressure head tool 4 and the lower pressure head tool 7 determined in step 11; wherein the curved surface angles of the upper pressure head tool 7 and the lower pressure head tool 4 are as follows: Figure 4 As shown;

[0182] Step 13: Install the lower pressure head tool 4 selected in step 12 on one of the lower fixing seats 3, and install the upper pressure head tool 7 selected in step 12 on the upper fixing seat 6; remove the other lower fixing seat 3, for example, only keep the lower fixing seat 3 on the right side and remove the lower fixing seat 3 on the left side;

[0183] Step 14: Align the lower pressure head tool 4 and the upper pressure head tool 7 vertically by adjusting the oil cylinder 105 accordingly;

[0184] Step 15: placing the middle part of the pipe column sample 0 on the lower pressure head tool 7;

[0185] Step 16: Install an inner wall multi-arm distance meter 12 on the pipe string sample 0 for measuring the change in the outer diameter of the pipe string sample 0; wherein, in Example 3, the structure of the pipe string deformation test device under the combined working condition of simulating internal pressure and external load is as follows: Figure 3 As shown;

[0186] Step 17: The loading cylinder 5 controls the upper pressure head tool 7 to move downward until it contacts the surface of the pipe string sample 0;

[0187] Step 18: The loading cylinder 5 controls the lower pressure head tool 7 to move downward at a set speed to apply pressure to the pipe string sample 0 until the pipe string sample 0 yields;

[0188] In this process, the load sensor 8 detects the test pressure applied by the loading cylinder 5 to the pipe string sample 0, and the inner wall multi-arm distance meter 12 measures the change in the inner diameter of the pipe string sample 0;

[0189] The data monitored by the load sensor 8 and the inner wall multi-arm distance meter 12 are transmitted to the computer to obtain the relationship curve between the load test pressure on the curved surface and the change in inner diameter of the pipe string sample 0.

[0190] Embodiment 4:

[0191] The method for testing the deformation of a pipe string under a simulated curved surface external load condition is implemented using the pipe string deformation testing device under a simulated internal pressure and external load combined condition in Example 2, and includes the following steps:

[0192] Step 11: Determine the lower pressure head tool 4 and the upper pressure head tool 7 that match the pipe string sample 0 to be tested;

[0193] The specifications of the pipe column sample 0 to be tested in Example 4 are: outer diameter 139.7 mm, wall thickness 10.25 m, length 1 m;

[0194] Column sample 0 steel grade: P110;

[0195] The length of the lower pressure head tool 4 and the upper pressure head tool 7 along the axial direction of the pipe string sample 0 is 260 mm;

[0196] Step 12: Select a tool having a set curved surface angle from the lower pressure head tool 4 and the upper pressure head tool 7 determined in step 11;

[0197] Among them, the curved surface angle of the lower pressure head tool 4 and the upper pressure head tool 7 is 120°;

[0198] Step 13: Install the lower pressure head tool 4 selected in step 12 on one of the lower fixed seats 3, and install the upper pressure head tool 7 selected in step 12 on the upper fixed seat 6;

[0199] Step 14: Align the lower pressure head tool 4 and the upper pressure head tool 7 vertically by adjusting the oil cylinder 105 accordingly;

[0200] Step 15: placing the middle part of the pipe column sample 0 on the lower pressure head tool 7;

[0201] Step 16: Installing an inner wall multi-arm distance meter 12 on the pipe string sample 0 for measuring the change in the outer diameter of the pipe string sample 0;

[0202] Step 17: The loading cylinder 5 controls the upper pressure head tool 7 to move downward until it contacts the surface of the pipe string sample 0;

[0203] Step 18: The loading cylinder 5 controls the lower pressure head tool 7 to move downward at a speed of 1 mm / min to apply pressure to the pipe string sample 0 until the pipe string sample 0 yields;

[0204] In this process, the load sensor 8 detects the test pressure applied by the loading cylinder 5 to the pipe string sample 0, and the inner wall multi-arm distance meter 12 measures the change in the inner diameter of the pipe string sample 0;

[0205] The data monitored by the load sensor 8 and the inner wall multi-arm distance meter 12 are transmitted to the computer to obtain the relationship curve between the load test pressure on the curved surface and the change in inner diameter of the pipe string sample 0.

[0206] Among them, the relationship curve between the curved surface external load test pressure and the inner diameter change of the pipe string sample 0 when the curved surface angle of the lower pressure head tool 4 and the upper pressure head tool 7 in Example 4 is 120° is as follows: Figure 5 As shown by Figure 5 It can be seen that when the external load test pressure on the curved surface reaches 1445KN and the pipe diameter changes to 7.2mm, the sample begins to yield, that is, the yield strength is 1445KN.

[0207] Embodiment 5:

[0208] The method for testing the deformation of a pipe string under a simulated curved surface external load condition is implemented using the pipe string deformation testing device under a simulated internal pressure and external load combined condition in Example 2, and includes the following steps:

[0209] Step 11: Determine the lower pressure head tool 4 and the upper pressure head tool 7 that match the pipe string sample 0 to be tested;

[0210] Among them, the specifications of the pipe column sample 0 to be tested in Example 5 are: outer diameter 139.7 mm, wall thickness 10.25 m, length 1 m;

[0211] Column sample 0 steel grade: P110;

[0212] The length of the lower pressure head tool 4 and the upper pressure head tool 7 along the axial direction of the pipe string sample 0 is 260 mm;

[0213] Step 12: Select a tool having a set curved surface angle from the lower pressure head tool 4 and the upper pressure head tool 7 determined in step 11;

[0214] Among them, the curved surface angle of the lower pressure head tool 4 and the upper pressure head tool 7 is 140°;

[0215] Step 13: Install the lower pressure head tool 4 selected in step 12 on one of the lower fixed seats 3, and install the upper pressure head tool 7 selected in step 12 on the upper fixed seat 6;

[0216] Step 14: Align the lower pressure head tool 4 and the upper pressure head tool 7 vertically by adjusting the oil cylinder 105 accordingly;

[0217] Step 15: placing the middle part of the pipe column sample 0 on the lower pressure head tool 7;

[0218] Step 16: Installing an inner wall multi-arm distance meter 12 on the pipe string sample 0 for measuring the change in the outer diameter of the pipe string sample 0;

[0219] Step 17: The loading cylinder 5 controls the upper pressure head tool 7 to move downward until it contacts the surface of the pipe string sample 0;

[0220] Step 18: The loading cylinder 5 controls the lower pressure head tool 7 to move downward at a speed of 1 mm / min to apply pressure to the pipe string sample 0 until the pipe string sample 0 yields;

[0221] In this process, the load sensor 8 detects the test pressure applied by the loading cylinder 5 to the pipe string sample 0, and the inner wall multi-arm distance meter 12 measures the change in the inner diameter of the pipe string sample 0;

[0222] The data monitored by the load sensor 8 and the inner wall multi-arm distance meter 12 are transmitted to the computer to obtain the relationship curve between the load test pressure on the curved surface and the change in inner diameter of the pipe string sample 0.

[0223] Among them, when the curved surface angle of the lower pressure head tool 4 and the upper pressure head tool 7 in Example 5 is 140°, the relationship curve between the curved surface external load test pressure and the inner diameter change of the pipe string sample 0 is as follows: Figure 6 As shown by Figure 6 It can be seen that when the external load test pressure of the curved surface reaches 2311KN and the pipe diameter changes to 6.5mm, the sample begins to yield, that is, the yield strength is 2311KN.

[0224] Embodiment 6:

[0225] The method for testing the deformation of a pipe string under the combined working condition of simulated internal pressure and curved surface external load is implemented by using the pipe string deformation testing device under the combined working condition of simulated internal pressure and external load in Example 1, and includes the following steps:

[0226] Step 21: Determine the pipe string sample 0 to be tested and the lower pressure head tool 4 and the upper pressure head tool 7 that match the pipe string sample 0 to be tested;

[0227] Step 22: Install the lower pressure head tool 4 selected in step 21 on one of the lower fixed seats 3, and install the upper pressure head tool 7 selected in step 22 on the upper fixed seat 6;

[0228] Step 23: Align the lower pressure head tool 4 and the upper pressure head tool 7 vertically by adjusting the oil cylinder 105 accordingly;

[0229] Step 24: Place the middle of the pipe string sample 0 on the lower pressure head tool 7, install sealing covers 10 at both ends of the pipe string sample 0, and then adjust the positions of the two clamping supports 2 through two clamping cylinders 103 to clamp the pipe string sample 0;

[0230] Step 25: Install an outer wall clamping distance meter on the pipe string sample 0 for measuring the change of the outer diameter of the pipe string sample 0; wherein, in Example 6, the structure of the pipe string deformation test device under the combined working condition of simulating internal pressure and external load is as follows: Figure 7 As shown;

[0231] Step 26: Connect the water supply pipe 901 to the water injection port 1001 of one of the sealing covers 10, and inject water into the pipe string sample 0 through the hydraulic pump station 9 to increase the pressure, so that the hydraulic load value in the pipe string sample 0 reaches the set internal pressure value;

[0232] Step 27: The loading cylinder 5 controls the upper pressure head tool 7 to move downward until it contacts the surface of the pipe string sample 0;

[0233] Step 28: The loading cylinder 5 controls the lower pressure head tool 7 to move downward to reach the set maximum force value of the external extrusion load;

[0234] In this process, the load sensor 8 detects the external squeeze load value applied by the loading cylinder 5 to the pipe string sample 0, and the outer wall clamping distance meter 11 measures the change in the outer diameter of the pipe string sample 0;

[0235] The data monitored by the load sensor 8 and the outer wall clamping distance meter 11 are transmitted to the computer to obtain the relationship curve between the internal pressure of the pipe string sample 0 and the external load value-outer diameter change under the composite working condition of the curved surface external load.

[0236] Embodiment 7:

[0237] The method for testing the deformation of a pipe string under the combined working condition of simulated internal pressure and curved surface external load is implemented by using the pipe string deformation testing device under the combined working condition of simulated internal pressure and external load in Example 1, and includes the following steps:

[0238] Step 21: Determine the lower pressure head tool 4 and the upper pressure head tool 7 that match the pipe string sample 0 to be tested;

[0239] Among them, the specifications of the pipe column sample 0 to be tested in Example 7 are: outer diameter 139.7 mm, inner diameter 119 mm, length 1 m;

[0240] Column sample 0 steel grade: P110;

[0241] The length of the lower pressure head tool 4 and the upper pressure head tool 7 along the axial direction of the pipe string sample 0 is 260 mm;

[0242] Step 22: Install the lower pressure head tool 4 selected in step 21 on one of the lower fixed seats 3, and install the upper pressure head tool 7 selected in step 21 on the upper fixed seat 6;

[0243] Step 23: Align the lower pressure head tool 4 and the upper pressure head tool 7 vertically by adjusting the oil cylinder 105 accordingly;

[0244] Step 24: Place the middle of the pipe string sample 0 on the lower pressure head tool 7, install sealing covers 10 at both ends of the pipe string sample 0, and then adjust the positions of the two clamping supports 2 through two clamping cylinders 103 to clamp the pipe string sample 0;

[0245] Step 25: Installing an outer wall clamping distance meter on the pipe string sample 0 for measuring the change of the outer diameter of the pipe string sample 0;

[0246] Step 26: Connect the water supply pipe 901 to the water injection port 1001 of one of the sealing covers 10, and inject water into the pipe string sample 0 through the hydraulic pump station 9 to increase the pressure, so that the hydraulic load value in the pipe string sample 0 reaches the set internal pressure value of 90 MPa;

[0247] Step 27: The loading cylinder 5 controls the upper pressure head tool 7 to move downward until it contacts the surface of the pipe string sample 0;

[0248] Step 28: The loading cylinder 5 controls the lower pressure head tool 7 to move downward to reach the set maximum force value of the external squeeze load of 5000KN;

[0249] In this process, the load sensor 8 detects the external squeeze load value applied by the loading cylinder 5 to the pipe string sample 0, and the outer wall clamping distance meter 11 measures the change in the outer diameter of the pipe string sample 0;

[0250] The data monitored by the load sensor 8 and the outer wall clamping distance meter 11 are transmitted to the computer to obtain the relationship curve between the internal pressure of the pipe string sample 0 and the external load value-outer diameter change under the composite working condition of the curved surface external load.

[0251] Among them, the relationship curve between the internal pressure of the pipe column sample 0 and the external load value-outer diameter change under the composite working condition of the curved surface external load in Example 7 is as follows: Figure 8 shown.

[0252] Embodiment 8:

[0253] The method for testing the deformation of a pipe string under a combined working condition of simulated internal pressure and shear load is implemented using the pipe string deformation testing device under a combined working condition of simulated internal pressure and external load in Example 1, and includes the following steps:

[0254] Step 31: Determine the lower pressure head tool 4 and the upper pressure head tool 7 that match the pipe string sample 0 to be tested;

[0255] Step 32: Install the lower pressure head tool 4 selected in step 31 on one of the lower fixing seats 3, and install the upper pressure head tool 7 selected in step 31 on the upper fixing seat 6; remove the other lower fixing seat 3;

[0256] Step 33: adjusting the oil cylinder 105 accordingly so that the distance between the lower pressure head tool 4 and the upper pressure head tool 7 reaches the set offset distance;

[0257] Step 34: Place the pipe sample 0 on the lower pressure head tool 4, and make the upper pressure head tool 7 located in the middle of the pipe sample 0; install sealing covers 10 at both ends of the pipe sample 0, and then adjust the positions of the two clamping supports 2 through two clamping cylinders 103 to clamp the pipe sample 0;

[0258] Step 35: Install an outer wall clamping distance meter 11 on the pipe string sample 0 for measuring the change in the inner diameter of the pipe string sample 0; wherein, in Example 8, the structure of the pipe string deformation test device under the combined working condition of simulating internal pressure and external load is as follows: Fig. 9 As shown;

[0259] Step 36: Connect the water supply pipe 901 to the water injection port 1001 of one of the sealing covers 10, and inject water into the pipe string sample 0 through the hydraulic pump station 9 to increase the pressure, so that the hydraulic load value in the pipe string sample 0 reaches the set internal pressure value;

[0260] Step 37: The loading cylinder 5 controls the upper pressure head tool 7 to move downward until it contacts the surface of the pipe string sample 0;

[0261] Step 38: The loading cylinder 5 controls the lower pressure head tool 7 to move downward to reach the set maximum shear load;

[0262] In this process, the load sensor 8 detects the shear load value applied by the loading cylinder 5 to the pipe string sample 0, and the outer wall clamping distance meter 11 measures the change in the outer diameter of the pipe string sample 0;

[0263] The data monitored by the load sensor 8 and the outer wall clamping distance meter 11 are transmitted to the computer to obtain the relationship curve between the shear load value and the outer diameter change under the internal pressure and shear load composite working condition of the pipe string sample 0.

[0264] Embodiment 9:

[0265] The method for testing the deformation of a pipe string under a combined working condition of simulated internal pressure and shear load is implemented using the pipe string deformation testing device under a combined working condition of simulated internal pressure and external load in Example 1, and includes the following steps:

[0266] Step 31: Determine the lower pressure head tool 4 and the upper pressure head tool 7 that match the pipe string sample 0 to be tested;

[0267] Among them, the specifications of the pipe column sample 0 to be tested in Example 9 are: outer diameter 144.7mm, wall thickness 15.2m, length 1m;

[0268] Column sample 0 steel grade: V110;

[0269] The length of the lower pressure head tool 4 and the upper pressure head tool 7 along the axial direction of the pipe string sample 0 is 260 mm;

[0270] Step 32: Install the lower pressure head tool 4 selected in step 31 on one of the lower fixing seats 3, and install the upper pressure head tool 7 selected in step 31 on the upper fixing seat 6; wherein, the lower fixing seat 3 on the right side is removed;

[0271] Step 33: By adjusting the oil cylinder 105 accordingly, the distance between the lower pressure head tool 4 and the upper pressure head tool 7 reaches the set offset distance; the distance between the vertical center planes of the lower pressure head tool 4 and the upper pressure head tool 7 in the left and right directions reaches the set offset distance of 200 mm;

[0272] Step 34: Place the pipe sample 0 on the lower pressure head tool 4, and make the upper pressure head tool 7 located in the middle of the pipe sample 0; install sealing covers 10 at both ends of the pipe sample 0, and then adjust the positions of the two clamping supports 2 through two clamping cylinders 103 to clamp the pipe sample 0;

[0273] Step 35: installing an outer wall clamping distance meter 11 on the pipe string sample 0 for measuring the change of the inner diameter of the pipe string sample 0;

[0274] Step 36: Connect the water supply pipe 901 to the water injection port 1001 of one of the sealing covers 10, and inject water into the pipe string sample 0 through the hydraulic pump station 9 to increase the pressure, so that the hydraulic load value in the pipe string sample 0 reaches the set internal pressure value of 90 MPa;

[0275] Step 37: The loading cylinder 5 controls the upper pressure head tool 7 to move downward until it contacts the surface of the pipe string sample 0;

[0276] Step 38: The loading cylinder 5 controls the lower pressure head tool 7 to move downward to reach the set shear load maximum value of 5000KN;

[0277] In this process, the load sensor 8 detects the shear load value applied by the loading cylinder 5 to the pipe string sample 0, and the outer wall clamping distance meter 11 measures the change in the outer diameter of the pipe string sample 0;

[0278] The data monitored by the load sensor 8 and the outer wall clamping distance meter 11 are transmitted to the computer to obtain the relationship curve between the shear load value and the outer diameter change under the internal pressure and shear load composite working condition of the pipe string sample 0.

[0279] Among them, the relationship curve between the internal pressure of the pipe column sample 0 and the shear load value-outer diameter change under the shear load composite working condition in Example 9 is as follows: Fig.10 As shown. The shear deformation of the pipe string sample has two obvious stages, namely the elastic stage and the yield plastic deformation stage. Under the shear load, the pipe string sample first undergoes elastic deformation. There is an obvious linear relationship between the shear load and the change in outer diameter. The slope of the straight line between the two is related to the elastic modulus of the pipe string sample. When the shear load on the pipe string sample exceeds its shear yield strength, the pipe string sample enters the yield plastic deformation stage. Fig.10 As known, the shear yield strength of the pipe column sample in Example 9 is 1525 KN.

[0280] Embodiment 10:

[0281] The method for testing the deformation of a pipe string under a combined working condition of simulated internal pressure and bending load is implemented using the pipe string deformation testing device under a combined working condition of simulated internal pressure and external load in Example 1, and includes the following steps:

[0282] Step 41: Determine the lower pressure head tool 4 and the upper pressure head tool 7 that match the pipe string sample 0 to be tested;

[0283] Step 42: Install the lower pressing head tool 4 selected in step 41 on the two lower fixing seats 3 respectively, and install the upper pressing head tool 7 selected in step 41 on the upper fixing seat 6;

[0284] Step 43: by adjusting the oil cylinder 105 accordingly, the two lower pressure head cutters 4 are symmetrically distributed on both sides of the upper pressure head cutter 7, and the distance between the two lower pressure head cutters 4 reaches the set cutter spacing;

[0285] Step 44: Place the pipe sample 0 on the lower pressure head tool 4, and make the upper pressure head tool 7 located in the middle of the pipe sample 0; install sealing covers 10 at both ends of the pipe sample 0, and then adjust the positions of the two clamping supports 2 through the two clamping cylinders 103 to clamp the pipe sample 0;

[0286] Step 45: Install an outer wall clamping distance meter 11 on the pipe string sample 0 for measuring the change in the inner diameter of the pipe string sample 0; wherein, in Example 10, the structure of the pipe string deformation test device under the combined working condition of simulating internal pressure and external load is as follows: Fig.11 As shown;

[0287] Step 46: Connect the water supply pipe 901 to the water injection port 1001 of one of the sealing covers 10, and inject water into the pipe string sample 0 through the hydraulic pump station 9 to increase the pressure, so that the hydraulic load value in the pipe string sample 0 reaches the set internal pressure value;

[0288] Step 47: The loading cylinder 5 controls the upper pressure head tool 7 to move downward until it contacts the surface of the pipe string sample 0;

[0289] Step 48: The loading cylinder 5 controls the lower pressure head tool 7 to move downward to reach the set maximum bending load;

[0290] In this process, the load sensor 8 detects the bending load value applied by the loading cylinder 5 to the pipe string sample 0, and the outer wall clamping distance meter 11 measures the change in the outer diameter of the pipe string sample 0;

[0291] The data monitored by the load sensor 8 and the outer wall clamping distance meter 11 are transmitted to the computer to obtain the relationship curve between the internal pressure of the pipe string sample 0 and the bending load value-outer diameter change under the bending load composite working condition.

[0292] Embodiment 11:

[0293] The method for testing the deformation of a pipe string under a combined working condition of simulated internal pressure and bending load is implemented using the pipe string deformation testing device under a combined working condition of simulated internal pressure and external load in Example 1, and includes the following steps:

[0294] Step 41: Determine the lower pressure head tool 4 and the upper pressure head tool 7 that match the pipe string sample 0 to be tested;

[0295] Among them, the specifications of the pipe column sample 0 to be tested in Example 11 are: outer diameter 139.7 mm, wall thickness 12.7 m, length 2 m;

[0296] Column sample 0 steel grade: P110;

[0297] Step 42: Install the lower pressing head tool 4 selected in step 41 on the two lower fixing seats 3 respectively, and install the upper pressing head tool 7 selected in step 41 on the upper fixing seat 6;

[0298] Step 43: by adjusting the oil cylinder 105 accordingly, the two lower pressure head cutters 4 are symmetrically distributed on both sides of the upper pressure head cutter 7, and the distance between the two lower pressure head cutters 4 reaches the set cutter spacing of 400 mm;

[0299] Step 44: Place the pipe sample 0 on the lower pressure head tool 4, and make the upper pressure head tool 7 located in the middle of the pipe sample 0; install sealing covers 10 at both ends of the pipe sample 0, and then adjust the positions of the two clamping supports 2 through the two clamping cylinders 103 to clamp the pipe sample 0;

[0300] Step 45: installing an outer wall clamping distance meter 11 on the pipe string sample 0 for measuring the change of the inner diameter of the pipe string sample 0;

[0301] Step 46: Connect the water supply pipe 901 to the water injection port 1001 of one of the sealing covers 10, and inject water into the pipe string sample 0 through the hydraulic pump station 9 to increase the pressure, so that the hydraulic load value in the pipe string sample 0 reaches the set internal pressure value of 90KN;

[0302] Step 47: The loading cylinder 5 controls the upper pressure head tool 7 to move downward until it contacts the surface of the pipe string sample 0;

[0303] Step 48: The loading cylinder 5 controls the lower pressure head tool 7 to move downward to reach the set bending load maximum value of 5000KN;

[0304] In this process, the load sensor 8 detects the bending load value applied by the loading cylinder 5 to the pipe string sample 0, and the outer wall clamping distance meter 11 measures the change in the outer diameter of the pipe string sample 0;

[0305] The data monitored by the load sensor 8 and the outer wall clamping distance meter 11 are transmitted to the computer to obtain the relationship curve between the internal pressure of the pipe string sample 0 and the bending load value-outer diameter change under the bending load composite working condition.

[0306] The relationship curve between the internal pressure of the pipe column sample 0 and the bending load value-outer diameter change under the bending load composite working condition in Example 11 is as follows: Fig.12It is shown that the bending deformation of the pipe string sample has two obvious stages, namely the elastic stage and the yield plastic deformation stage. The elastic yield strength of the sample is 788.43KN, the ultimate plastic load is 929.66KN, and it finally breaks and fails completely when the deformation is 15.86mm.

[0307] 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. A pipe string deformation testing device simulating internal pressure and external load combined working conditions, characterized in that: It includes a pipe clamp for clamping a pipe sample, a loading assembly for applying an external load to the pipe sample, a deformation detection member for detecting the deformation of the pipe sample, and a pressurizing assembly for applying an internal pressure to the pipe sample; The pipe column clamp comprises a support platform; The support platform is provided with two parallel clamping supports capable of clamping pipe column samples of different lengths; The loading assembly includes two lower fixing seats and an upper fixing seat; The top of the lower fixing seat is detachably connected with a lower pressure head tool, and the lower fixing seat is arranged on the support platform and can move along the axial direction of the pipe column sample; An upper pressure head tool is detachably connected to the bottom of the upper fixing seat, and the upper fixing seat is located on the upper part of the lower fixing seat; The end surfaces where the lower pressure head tool and the upper pressure head tool are in contact with the pipe string sample are cylindrical in structure; The top end of the upper fixing seat is fixedly connected to the bottom end of the piston rod of the loading cylinder, and the loading cylinder is fixedly arranged on the supporting platform.

2. The pipe string deformation testing device under the combined working condition of simulating internal pressure and external load according to claim 1, characterized in that: Support plates are vertically fixedly arranged at the left and right ends of the support platform; A guide rod is vertically fixed between the two support plates; The clamping support is slidably matched with the guide rod.

3. The pipe string deformation testing device under the combined working condition of simulating internal pressure and external load as claimed in claim 2, characterized in that: A clamping cylinder is provided at each of the back-facing ends of the two support plates; The piston rod end of the clamping oil cylinder passes through the corresponding support plate and is fixedly connected to the corresponding clamping support.

4. The pipe string deformation testing device under the combined working condition of simulating internal pressure and external load as claimed in claim 3, characterized in that: An adjustment cylinder is provided at each of the back-facing ends of the two support plates; The piston rod end of the adjusting oil cylinder passes through the corresponding supporting plate and is fixedly connected to the corresponding lower fixing seat.

5. The pipe string deformation testing device under the combined working condition of simulating internal pressure and external load as claimed in claim 4, characterized in that: Four bearing columns are fixed vertically upward on the top of the support platform; An upper crossbeam is fixedly arranged on the top of the load-bearing column; The loading cylinder is fixedly arranged on the upper cross beam.

6. The pipe string deformation testing device under the combined working condition of simulating internal pressure and external load as claimed in claim 5, characterized in that: A load sensor is arranged between the upper fixing seat and the piston rod of the loading oil cylinder.

7. The pipe string deformation testing device under the combined working condition of simulating internal pressure and external load as claimed in claim 6, characterized in that: The pressurizing component includes a water pressure pump station, and the outlet of the water pressure pump station is connected to a water supply pipe; Sealing covers are arranged at both ends of the pipe column sample, and one of the sealing covers is provided with a water injection port which is connected to the interior of the pipe column sample and can be connected to a water supply pipe.

8. The pipe string deformation testing device under the combined working condition of simulating internal pressure and external load as claimed in claim 7, characterized in that: The deformation detection part is an outer wall clamping distance meter used to measure the change of the outer diameter of the pipe string sample; The outer wall clamping distance meter comprises a deformation measuring sensor 1, a hook, and a deformation line 1 extending in the vertical direction and arranged between the deformation measuring sensor 1 and the hook; the deformation line 1 is located on the vertical center plane in the left-right direction of the upper fixing seat; The deformation measurement sensor 1 is fixedly arranged on the front end surface of the upper fixing seat; The hook is fixedly arranged on one of the lower fixing seats.

9. The pipe string deformation testing device under the combined working condition of simulating internal pressure and external load as claimed in claim 7, characterized in that: The deformation detection part is an inner wall multi-arm distance meter used to measure the change of the inner diameter of the pipe string sample; The inner wall multi-arm rangefinder comprises a support base, on which a support guide column extending vertically upward is fixedly arranged; The support guide column is provided with a first arm extending in the horizontal direction, and the position of the first arm in the vertical direction of the support guide column is adjustable; A second arm extending in the horizontal direction is arranged on the support guide column at the upper part of the first arm, and the second arm is slidably matched with the support guide column in the vertical direction; A spring support plate is arranged on the support guide column between the first arm and the second arm, and a spring capable of pressing toward the second arm is fixedly arranged on the upper part of the spring support plate; A bull's eye bearing is provided on the bottom side of the end of the first arm away from the supporting guide column and on the top side of the end of the second arm away from the supporting guide column; A second deformation line extending in a vertical direction is arranged between the first arm and the second arm, and a second deformation measuring sensor for detecting a deformation amount of the second deformation line is arranged on the second arm.

10. A method for testing pipe string deformation under a simulated curved surface external load condition, characterized in that: The method is implemented by using the pipe string deformation testing device under the combined working condition of simulating internal pressure and external load as claimed in claim 9, comprising the following steps: Step 11: Determine the lower pressure head tool and the upper pressure head tool that match the pipe string sample to be tested; Step 12: Select a tool having a set curved surface angle from the pressing head tool and the pressing head tool determined in step 11; Step 13: Install the lower pressure head tool selected in step 12 on one of the lower fixed seats, and install the upper pressure head tool selected in step 12 on the upper fixed seat; Step 14: Align the lower pressure head tool and the upper pressure head tool up and down by adjusting the oil cylinder accordingly; Step 15: Place the middle of the pipe sample on the lower pressure head tool; Step 16: Install an inner wall multi-arm distance meter on the pipe string sample for measuring the change of the outer diameter of the pipe string sample; Step 17: The loading cylinder controls the upper pressure head tool to move downward until it contacts the surface of the pipe string sample; Step 18: The loading cylinder controls the lower pressure head tool to move downward at a set speed to apply pressure to the pipe string sample until the pipe string sample yields; In this process, the load sensor detects the test pressure applied by the loading cylinder to the pipe sample, and the inner wall multi-arm distance meter measures the change in the inner diameter of the pipe sample; The data monitored by the load sensor and the inner wall multi-arm distance meter are transmitted to the computer to obtain the relationship curve between the load test pressure and the change in inner diameter of the curved surface of the pipe string sample.

11. A pipe string deformation test method under a combined working condition of simulated internal pressure and curved surface external load, characterized in that: The method is implemented by using the pipe string deformation testing device under the combined working condition of simulating internal pressure and external load as claimed in claim 8, including the following steps: Step 21: Determine the lower pressure head tool and the upper pressure head tool that match the pipe string sample to be tested; Step 22: Install the lower pressure head tool selected in step 21 on one of the lower fixed seats, and install the upper pressure head tool selected in step 21 on the upper fixed seat; Step 23: Align the lower pressure head tool and the upper pressure head tool up and down by adjusting the oil cylinder accordingly; Step 24: Place the middle of the pipe string sample on the lower pressure head tool, install sealing covers on both ends of the pipe string sample, and then adjust the positions of the two clamping supports through two clamping cylinders to clamp the pipe string sample; Step 25: Installing an outer wall clamping distance meter on the pipe string sample for measuring the change of the outer diameter of the pipe string sample; Step 26: Connect the water supply pipe to the water injection port of one of the sealing covers, and inject water into the pipe string sample through the hydraulic pump station to increase the pressure, so that the hydraulic load value in the pipe string sample reaches the set internal pressure value; Step 27: The loading cylinder controls the upper pressure head tool to move downward until it contacts the surface of the pipe string sample; Step 28: The loading cylinder controls the lower pressure head tool to move downward to reach the set maximum force value of the external extrusion load; In this process, the load sensor detects the external squeeze load value applied by the loading cylinder to the pipe sample, and the outer wall clamping distance meter measures the change in the outer diameter of the pipe sample; The data monitored by the load sensor and the outer wall clamping distance meter are transmitted to the computer to obtain the relationship curve between the internal pressure of the pipe string sample and the external load value-outer diameter change under the composite working condition of the curved surface external load.

12. A method for testing pipe string deformation under a combined working condition of simulated internal pressure and shear load, characterized in that: The method is implemented by using the pipe string deformation testing device under the combined working condition of simulating internal pressure and external load as claimed in claim 8, including the following steps: Step 31: Determine a lower pressure head tool and an upper pressure head tool that match the pipe string sample to be tested; Step 32: Install the lower pressure head tool selected in step 31 on one of the lower fixed seats, and install the upper pressure head tool selected in step 31 on the upper fixed seat; Step 33: Adjust the oil cylinder accordingly so that the distance between the lower pressure head tool and the upper pressure head tool reaches the set offset distance; Step 34: Place the pipe string sample on the lower pressure head tool, and make the upper pressure head tool located in the middle of the pipe string sample; install sealing covers at both ends of the pipe string sample, and then adjust the positions of the two clamping supports through two clamping cylinders to clamp the pipe string sample; Step 35: Installing an outer wall clamping distance meter on the pipe string sample for measuring the change of the inner diameter of the pipe string sample; Step 36: Connect the water supply pipe to the water injection port of one of the sealing covers, and inject water into the pipe string sample through the hydraulic pump station to increase the pressure, so that the hydraulic load value in the pipe string sample reaches the set internal pressure value; Step 37: The loading cylinder controls the upper pressure head tool to move downward until it contacts the surface of the pipe string sample; Step 38: The loading cylinder controls the lower pressure head tool to move downward to reach the set maximum shear load; In this process, the load sensor detects the shear load value applied by the loading cylinder to the pipe sample, and the outer wall clamping distance meter measures the change in the outer diameter of the pipe sample; The data monitored by the load sensor and the outer wall clamping distance meter are transmitted to the computer to obtain the relationship curve between the shear load value and the outer diameter change under the combined working condition of the internal pressure and shear load of the pipe string sample.

13. A method for testing pipe string deformation under a combined working condition of simulated internal pressure and bending load, characterized in that: The method is implemented by using the pipe string deformation testing device under the combined working condition of simulating internal pressure and external load as claimed in claim 8, including the following steps: Step 41: Determine a lower pressure head tool and an upper pressure head tool that match the pipe string sample to be tested; Step 42: Install the lower pressure head tool selected in step 41 on the two lower fixed seats respectively, and install the upper pressure head tool selected in step 41 on the upper fixed seat; Step 43: The two lower pressure head tools are symmetrically distributed on both sides of the upper pressure head tool by adjusting the oil cylinder accordingly, and the distance between the two lower pressure head tools reaches the set tool spacing; Step 44: placing the pipe string sample on the lower pressure head tool, and making the upper pressure head tool be located in the middle of the pipe string sample; installing sealing covers at both ends of the pipe string sample, and then adjusting the positions of the two clamping supports by two clamping cylinders so as to clamp the pipe string sample; Step 45: Installing an outer wall clamping distance meter on the pipe string sample for measuring the change of the inner diameter of the pipe string sample; Step 46: Connect the water supply pipe to the water injection port of one of the sealing covers, and inject water into the pipe string sample through the hydraulic pump station to increase the pressure, so that the hydraulic load value in the pipe string sample reaches the set internal pressure value; Step 47: The loading cylinder controls the upper pressure head tool to move downward until it contacts the surface of the pipe string sample; Step 48: The loading cylinder controls the lower pressure head tool to move downward to reach the set maximum bending load; In this process, the load sensor detects the bending load value applied by the loading cylinder to the pipe sample, and the outer wall clamping distance meter measures the change in the outer diameter of the pipe sample; The data monitored by the load sensor and the outer wall clamping distance meter are transmitted to the computer to obtain the relationship curve between the internal pressure of the pipe string sample and the bending load value-outer diameter change under the combined working condition of the bending load.

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