Marine riser auxiliary pipe joint bending fatigue and sealing test device and test method

Abstract

The invention discloses a bending fatigue and sealing test device for a marine riser auxiliary pipe joint. The periphery of a pressing sleeve is sleeved with a sleeve, and the inner wall of the pressing sleeve surrounds the joint of a male joint and a female joint of a marine riser auxiliary pipe; the counterweight unit at the outer port of the female joint is connected with a long-time pressure maintaining mechanism; the pressing unit at the outer port of the male joint is in transmission connection with the excitation unit; and the strain gauges arranged on the circumference of the sleeve are all in signal connection with the data acquisition unit. The invention further discloses a bending fatigue and sealing test method for the marine riser auxiliary pipe joint. The method comprises the steps that a sample is fixed; determining a loading frequency and a support span; the long-time pressure maintaining mechanism, the excitation unit and the data acquisition unit are connected; the long-time pressure maintaining mechanism is started, and the excitation unit is started; bending fatigue and sealing performance are obtained through leakage conditions and analysis test data results. According to the device and the method, the high-frequency and periodically-changing bending load is provided, and the real load and the fatigue life of the sample are obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of offshore oil drilling equipment, and relates to a device for testing bending fatigue and sealing of a riser auxiliary pipe joint, and also relates to a method for testing bending fatigue and sealing of a riser auxiliary pipe joint. Background Art

[0002] Deepwater offshore drilling operations are highly risky and complex. The riser and auxiliary pipe system is a piping system used in deepwater offshore drilling. It plays the role of throttling, well pressure and mud pressurization in oil and gas drilling operations. The riser and auxiliary pipe joints are key components connecting the riser and auxiliary pipes. Due to the complexity of the marine environment, factors such as currents, waves and wind will impose cyclic loads on the riser and auxiliary pipe joints. These cyclic loads will cause stress concentration and stress cycling at the joint connection, thereby causing fatigue damage.

[0003] In order to ensure that the auxiliary pipe joints of watertight pipes can withstand long-term cyclic loads, it is necessary to test their sealing performance and bending fatigue life before they are officially put into use. This process includes testing the sealing performance and fatigue performance of the joint connection to evaluate its reliability and durability in actual use. Only through sufficient testing and evaluation can we ensure that the connection of the auxiliary pipe joints of watertight pipes can operate safely and reliably in the deep-water drilling environment of the ocean. At present, there are no relevant methods and standards for the bending fatigue and sealing performance testing of the auxiliary pipe joints of watertight pipes in China.

[0004] Therefore, it is urgent to develop a new bending fatigue and sealing test device for riser auxiliary pipe joints. Summary of the invention

[0005] The purpose of the present invention is to provide a device for testing the bending fatigue and sealing performance of the auxiliary pipe joints of a watertight pipe, which solves the problem in the prior art that it is difficult to determine the bending fatigue and sealing performance of the auxiliary pipe joints of a watertight pipe in a non-marine platform environment.

[0006] Another object of the present invention is to provide a method for testing the bending fatigue and sealing performance of the auxiliary pipe joints of a riser, which solves the problem in the prior art that it is difficult to determine the bending fatigue and sealing performance of the auxiliary pipe joints of a riser in a non-offshore platform environment.

[0007] The technical solution adopted in the present invention is a bending fatigue and sealing test device for riser auxiliary pipe joints, including a compression sleeve, a sleeve is mounted on the outer periphery of the compression sleeve, and the inner wall of the compression sleeve surrounds the joints between the riser auxiliary pipe male joint and the riser auxiliary pipe female joint; a support unit is provided at the extension section of the riser auxiliary pipe female joint, a sealing plate is installed at the outer port of the riser auxiliary pipe female joint, a counterweight unit is installed at the outer end face of the sealing plate, and the counterweight unit is externally connected to a long-term pressure maintaining mechanism; a support unit is provided at the extension section of the riser auxiliary pipe male joint, a sealing plate is provided at the outer port of the riser auxiliary pipe male joint, a clamping unit is provided at the outer end face of the sealing plate, and the clamping unit is transmission-connected to the excitation unit; a plurality of strain gauges are evenly installed on the circumference of the sleeve, and all strain gauges are signal-connected to the data acquisition unit.

[0008] Another technical solution adopted by the present invention is a method for testing the bending fatigue and sealing of a riser auxiliary pipe joint, which is implemented by using the above-mentioned device for testing the bending fatigue and sealing of a riser auxiliary pipe joint according to the following steps:

[0009] Step 1: Sleeve the auxiliary pipe male joint and the auxiliary pipe female joint of the watertight riser together, and fix them by pressing sleeve and sleeve to form a sample;

[0010] Step 2: Establish a finite element model for the sample to analyze and obtain the loading frequency and support span;

[0011] Step 3: Install the sample on the test bench, attach the strain gauge, and connect the long-time pressure-holding mechanism, the excitation unit, and the data acquisition unit;

[0012] Step 4, starting the long-time pressure-maintaining mechanism to load the internal pressure on the sample and perform a sealing test;

[0013] Step 5, start the excitation unit to simulate the bending conditions in actual use, perform a bending fatigue test, and obtain the real load and fatigue data of the sample through the data acquisition unit;

[0014] Step 6: By detecting the leakage of the sample and analyzing the test data results, the bending fatigue and sealing performance of the riser and auxiliary pipe joints of the sample are obtained.

[0015] The beneficial effects of the present invention include the following aspects:

[0016] 1) The polarization movement of the riser auxiliary pipe joint fixed on the fatigue test bench not only truly simulates the wave motion of the riser auxiliary pipe during offshore drilling conditions, but also realizes the visual inspection and detection of underwater drilling equipment on land;

[0017] 2) Easy to install and operate, the dynamic emergency collection system can monitor the alternating bending stress borne by the sample in real time;

[0018] 3) This test method can be adapted to the bending fatigue and sealing performance of different types of riser auxiliary pipe joints, and has strong applicability and versatility;

[0019] 4) It can quickly and accurately evaluate the bending fatigue and sealing performance of the auxiliary pipe joints of the riser, provide reliable reference data for users in related industries and fields to guide product design and selection, and provide a method guarantee for the dynamic sealing durability test of related pipes in the later stage of marine equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the test device used in the method of the present invention;

[0021] Figure 2 It is a partial structural schematic diagram of the test device of the present invention.

[0022] In the figure, 1. pressing sleeve, 2. sleeve, 3. female joint of watertight riser auxiliary pipe, 4. male joint of watertight riser auxiliary pipe, 5. counterweight unit, 6. long-time pressure maintaining mechanism, 7. supporting unit 1, 8. supporting unit 2, 9. clamping unit, 10. coupling, 11. excitation unit, 12. data acquisition unit, 13. sealing plate 1, 14. sealing plate 2, 15. fastening screws, 16. sealing ring. DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Reference Figure 1 , Figure 2 The structure of the test device of the present invention is as follows: it includes a press sleeve 1, two sets of support units, a long-time pressure-maintaining mechanism 6, an excitation unit 11 and a data acquisition unit 12.

[0025] A sleeve 2 is sleeved on the outer periphery of the pressing sleeve 1. The pressing sleeve 1 is a petal-type structure, and the sleeve 2 is an integral ring-hub type structure. The sleeve 2 is fixed to the pressing sleeve 1 as a whole by a plurality of fastening screws 15. The inner wall of the pressing sleeve 1 surrounds the joint of the watertight pipe auxiliary pipe male joint 4 and the watertight pipe auxiliary pipe female joint 3. The watertight pipe auxiliary pipe male joint 4 and the watertight pipe auxiliary pipe female joint 3 are butt-jointed together to be called a watertight pipe auxiliary pipe male and female joint. The sleeve joint surfaces of the watertight pipe auxiliary pipe male joint 4 and the watertight pipe auxiliary pipe female joint 3 are provided with at least two sealing rings 16, and the two sealing rings 16 are both installed in the sealing groove of the inner wall of the watertight pipe auxiliary pipe female joint 3.

[0026] The extension section of the auxiliary pipe female joint 3 of the watertight pipe is provided with a support unit 7 ( Figure 1On the left side), a sealing plate 13 is installed at the outer end of the watertight pipe auxiliary pipe female joint 3, and a counterweight unit 5 is installed on the outer end face of the sealing plate 13 to prevent the sample from tipping over. The counterweight unit 5 is externally connected to a long-time pressure-maintaining mechanism 6, which can load pressure inside the watertight pipe auxiliary pipe male and female joints to test the sealing reliability of the joints;

[0027] The extension section of the auxiliary pipe male joint 4 of the watertight pipe is provided with a support unit 28 ( Figure 1 On the right side), a sealing plate 14 is provided at the outer end of the auxiliary pipe male joint 4 of the watertight pipe, and a clamping unit 9 is provided on the outer end surface of the sealing plate 14. The clamping unit 9 is connected to the excitation unit 11 through a coupling 10. The excitation unit 11 can provide a high-frequency, periodically changing bending load for the auxiliary pipe joint sample of the watertight pipe;

[0028] Multiple sets of strain gauges are evenly installed on the circumference of the sleeve 2, and all strain gauges are connected to the data acquisition unit 12 signal to obtain the true load history of the sample. The bending fatigue life of the male and female joints of the watertight pipe auxiliary pipe is obtained through subsequent calculations.

[0029] The support unit 1 7 and the support unit 2 8 can be adjusted axially, and a reasonable support span is determined according to the analysis results of the finite element method.

[0030] The working principle of the present invention is: the auxiliary pipe male joint 4 and the auxiliary pipe female joint 3 of the watertight pipe to be tested are butt-jointed together, fixed by the compression sleeve 1 and the sleeve 2 to form a sample, and the sample is fixed on the support unit of the resonant bending fatigue test bench; during the test, the long-time pressure-maintaining mechanism 6 is used to load the internal pressure to the sample, and the alternating bending load is applied to the sample by the excitation unit 11, and the excitation controller adjusts the magnitude of the excitation force by the frequency converter; in order to obtain accurate test data, during the test, the data acquisition unit 12 (dynamic emergency acquisition) is used to continuously collect and output and dynamically monitor the alternating bending stress carried by the sample in real time. The output data mainly includes information such as strain range, number of loading cycles, internal pressure, etc., and the bending fatigue and sealing performance of the auxiliary pipe joint of the watertight pipe are obtained by analyzing and evaluating the test data. These data and results can provide important references for the design and improvement of watertight pipe joints, thereby improving their reliability and durability, and provide strong support for research and application in related fields.

[0031] The method for testing the bending fatigue and sealing of the auxiliary pipe joint of a watertight pipe of the present invention is implemented by using the above-mentioned device for testing the bending fatigue and sealing of the auxiliary pipe joint of a watertight pipe according to the following steps:

[0032] Step 1, prepare a set of riser auxiliary pipe joints to be tested, sleeve the riser auxiliary pipe male joint 4 and the riser auxiliary pipe female joint 3 together, and fix them by the compression sleeve 1 and the sleeve 2 to form a sample;

[0033] Step 2: Establish a finite element model for the sample and analyze it to obtain the first-order bending vibration mode of the sample. The analysis results will determine the loading frequency of the sample and the support span on the test bench;

[0034] Step 3: Install the sample on the test bench and adjust the support span so that the coaxiality of the sample and the power end and the horizontality of the sample reach the visual level; after the adjustment is completed, paste the strain gauge, connect the long-time pressure holding mechanism 6, the excitation unit 11, and the data acquisition unit 12, see Figure 1 ;

[0035] Step 4, start the long-time pressure-maintaining mechanism 6 to load the sample with internal pressure and perform a sealing test;

[0036] Step 5, start the excitation unit 11, apply a certain bending force and periodic load to the sample, simulate the bending conditions in actual use, perform a bending fatigue test, and obtain the real load and fatigue data of the sample through the data acquisition unit 12;

[0037] Step 6: By detecting the leakage of the sample and analyzing the test data results, the bending fatigue and sealing performance of the riser auxiliary pipe joint can be obtained.

[0038] Example 1

[0039] The test was conducted on a certain type of riser auxiliary pipe joint, with an auxiliary pipe outer diameter of 127 mm, a sample length of 9550 mm, and a support span of 5960 mm. The bending fatigue and sealing test device for the riser auxiliary pipe joint was used and the following steps were followed:

[0040] Step 1, prepare a set of riser auxiliary pipe joints that need to be tested, put the riser auxiliary pipe male joint 4 and the riser auxiliary pipe female joint 3 together, and fix them by pressing sleeve 1 and sleeve 2 to form a sample.

[0041] Step 2: Establish a finite element model for the sample and analyze it to obtain the first-order bending vibration mode of the sample. The analysis results will determine the loading frequency of the sample and the support span on the test bench.

[0042] Step 3: Install the sample on the test bench and adjust the support span so that the coaxiality of the sample and the power end and the horizontality of the sample reach the visual level;

[0043] After adjustment, paste the strain gauge, connect the long-time pressure-maintaining mechanism 6, the excitation unit 11, and the data acquisition unit 12, see Figure 1 .

[0044] Step 4: Start the long-time pressure-maintaining mechanism 6 to load the internal pressure on the sample. The water pressure of the long-time pressure-maintaining mechanism 6 is 10.1 MPa, and a sealing test is performed.

[0045] Step 5: Start the excitation unit 11, and the excitation frequency of the excitation unit 11 is 5.8 Hz. Apply a certain bending force and periodic load to the sample to simulate the bending conditions in actual use, perform a bending fatigue test, and obtain the real load and fatigue data of the sample through the data acquisition unit 12.

[0046] Step 6. By detecting the leakage of the sample and analyzing the test data results, the bending fatigue and sealing performance of the auxiliary pipe joint of the watertight pipe are obtained, and the data are recorded as shown in Table 1 below.

[0047] Table 1. Test record data of Example 1

[0048] The total number of test cycles is 813936 times Sealing performance No leakage Fatigue performance No cracks

[0049] After analyzing the test data results, it was found that the bending fatigue life of this type of riser auxiliary pipe joint is 813936 times. At the same time, the sealing performance meets the technical requirements.

[0050] Example 2

[0051] The test was conducted on a certain type of riser auxiliary pipe joint, with an auxiliary pipe outer diameter of 127 mm, a sample length of 8950 mm, and a support span of 5730 mm. The bending fatigue and sealing test device for the riser auxiliary pipe joint was used and the following steps were followed:

[0052] Step 1, prepare a set of riser auxiliary pipe joints that need to be tested, put the riser auxiliary pipe male joint 4 and the riser auxiliary pipe female joint 3 together, and fix them by pressing sleeve 1 and sleeve 2 to form a sample.

[0053] Step 2: Establish a finite element model for the sample and analyze it to obtain the first-order bending vibration mode of the sample. The analysis results will determine the loading frequency of the sample and the support span on the test bench.

[0054] Step 3: Install the sample on the test bench and adjust the support span so that the coaxiality of the sample and the power end and the horizontality of the sample reach the visual level; after the adjustment is completed, paste the strain gauge, connect the long-time pressure holding mechanism 6, the excitation unit 11, and the data acquisition unit 12, see Figure 1 .

[0055] Step 4: Start the long-time pressure-maintaining mechanism 6 to load the internal pressure on the sample. The water pressure of the long-time pressure-maintaining mechanism 6 is 10.4 MPa, and a sealing test is performed.

[0056] Step 5: Start the excitation unit 11, the excitation frequency of the excitation unit 11 is 3.5 Hz. Apply a certain bending force and periodic load to the sample to simulate the bending conditions in actual use, perform a bending fatigue test, and obtain the real load and fatigue data of the sample through the data acquisition unit 12.

[0057] Step 6: By testing the leakage of the sample and analyzing the test data results, the bending fatigue and sealing performance of the auxiliary pipe joint of the watertight pipe are obtained. The recorded data are shown in Table 2 below.

[0058] Table 2. Test record data of Example 2

[0059] The total number of test cycles is 1311321 times Sealing performance No leakage Fatigue performance No cracks

[0060] After analyzing the test data results, it was found that the bending fatigue life of this type of riser auxiliary pipe joint is 1311321 times. At the same time, the sealing performance meets the technical requirements.

[0061] Example 3

[0062] The test was conducted on a certain type of riser auxiliary pipe joint, with an auxiliary pipe outer diameter of 127 mm, a sample length of 8750 mm, and a support span of 5590 mm. The bending fatigue and sealing test device for the riser auxiliary pipe joint was used and the following steps were followed:

[0063] Step 1, prepare a set of riser auxiliary pipe joints that need to be tested, put the riser auxiliary pipe male joint 4 and the riser auxiliary pipe female joint 3 together, and fix them by pressing sleeve 1 and sleeve 2 to form a sample.

[0064] Step 2: Establish a finite element model for the sample and analyze it to obtain the first-order bending vibration mode of the sample. The analysis results will determine the loading frequency of the sample and the support span on the test bench.

[0065] Step 3: Install the sample on the test bench and adjust the support span so that the coaxiality of the sample and the power end and the horizontality of the sample reach the visual level; after the adjustment is completed, paste the strain gauge, connect the long-time pressure holding mechanism 6, the excitation unit 11, and the data acquisition unit 12, see Figure 1 .

[0066] Step 4: Start the long-time pressure-maintaining mechanism 6 to load the internal pressure on the sample. The water pressure of the long-time pressure-maintaining mechanism 6 is 10.1 MPa, and a sealing test is performed.

[0067] Step 5: Start the excitation unit 11, and the excitation frequency of the excitation unit 11 is 3.1 Hz. Apply a certain bending force and periodic load to the sample to simulate the bending conditions in actual use, perform a bending fatigue test, and obtain the real load and fatigue data of the sample through the data acquisition unit 12.

[0068] Step 6. By detecting the leakage of the sample and analyzing the test data results, the bending fatigue and sealing performance of the auxiliary pipe joint of the watertight pipe are obtained, and the data are recorded as shown in Table 3 below.

[0069] Table 3. Test record data of Example 3

[0070] The total number of test cycles is 928749 times Sealing performance No leakage Fatigue performance No cracks

[0071] After analyzing the test data results, it was found that the bending fatigue life of this type of riser auxiliary pipe joint is 928749 times. At the same time, the sealing performance meets the technical requirements.

Claims

1. A riser auxiliary pipe joint bending fatigue and sealing test device, characterized in that: It comprises a pressing sleeve (1), the outer circumference of which is provided with a sleeve (2), the inner wall of the pressing sleeve (1) surrounds the joints between the male joint (4) and the female joint (3) of the watertight pipe auxiliary pipe; the extension section of the female joint (3) of the watertight pipe auxiliary pipe is provided with a supporting unit (7), the outer port of the female joint (3) of the watertight pipe auxiliary pipe is provided with a sealing plate (13), the outer end face of the sealing plate (13) is provided with a counterweight unit (5), and the counterweight unit (5) is externally connected with a long-term pressure-maintaining mechanism (6); the extension section of the male joint (4) of the watertight pipe auxiliary pipe is provided with a supporting unit (8), the outer port of the male joint (4) of the watertight pipe auxiliary pipe is provided with a sealing plate (14), the outer end face of the sealing plate (14) is provided with a clamping unit (9), and the clamping unit (9) is transmission-connected to the excitation unit (11); a plurality of strain gauges are evenly installed on the circumference of the sleeve (2), and all strain gauges are signal-connected to the data acquisition unit (12).

2. The riser auxiliary pipe joint bending fatigue and sealing test device according to claim 1, characterized in that: The pressing sleeve (1) is a petal-type structure, the sleeve (2) is an integral ring-hub type structure, and the sleeve (2) is fixed to the pressing sleeve (1) as a whole by a plurality of fastening screws (15).

3. The riser auxiliary pipe joint bending fatigue and sealing test device according to claim 1, characterized in that: The long-time pressure-maintaining mechanism (6) is used to load pressure inside the male and female joints of the watertight pipe auxiliary pipe to test the sealing reliability of the joint.

4. The riser auxiliary pipe joint bending fatigue and sealing test device according to claim 1, characterized in that: The excitation unit (11) provides a high-frequency, periodically changing bending load for the riser auxiliary pipe joint specimen.

5. The riser auxiliary pipe joint bending fatigue and sealing test device according to claim 1, characterized in that: The sleeve joint surfaces of the watertight pipe auxiliary pipe male joint (4) and the watertight pipe auxiliary pipe female joint (3) are provided with at least two sealing rings (16), and the two sealing rings (16) are both installed in the sealing groove on the inner wall of the watertight pipe auxiliary pipe female joint (3).

6. A method for testing bending fatigue and sealing of auxiliary pipe joints of watertight pipes, using the device for testing bending fatigue and sealing of auxiliary pipe joints of watertight pipes according to any one of claims 1 to 5, characterized in that: Follow these steps to implement: Step 1, sleeve the auxiliary pipe male joint (4) of the watertight riser and the auxiliary pipe female joint (3) of the watertight riser together, and fix them by means of a press sleeve (1) and a sleeve (2) to form a sample; Step 2, establish a finite element model for the sample to analyze and obtain the loading frequency and support span; Step 3, installing the sample on the test bench, attaching the strain gauge, and connecting the long-time pressure-maintaining mechanism (6), the excitation unit (11), and the data acquisition unit (12); Step 4, starting the long-time pressure-maintaining mechanism (6) to load the internal pressure on the sample and perform a sealing test; Step 5, starting the vibration excitation unit (11), simulating the bending conditions in actual use, performing a bending fatigue test, and obtaining the real load and fatigue data of the sample through the data acquisition unit (12); Step 6, by detecting the leakage of the sample and analyzing the test data results, the bending fatigue and sealing performance of the riser auxiliary pipe joint of the sample are obtained.

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