JPWO2018234782A5 - - Google Patents

Description

In the oil and gas industry, the production of subsea pipelines suitable for installation and operation in ultra-deepwater to access deepwater reservoirs of oil and/or gas has developed steadily over the last two decades. Currently, small diameter pipes with a diameter of about 16 inches (about 40.6 cm) are installed at a depth of 3000 m . Large diameter pipes up to 32 inches (81.1 cm) in diameter are installed in water depths up to 2500 m . Future projects may require the installation and operation of pipes up to 3500m and possibly deeper.

The maximum allowable force depends on the outer diameter of the test ring. For example, for a ring with an outer diameter of about 30 inches (76.2 cm), the maximum allowable force exerted by the hydraulic ram is 0.5 cm . 1kN-6 . A range of 5 kN is preferred. However, the allowable force range also depends on the pressure in the pressure chamber. With no pressure applied to the pressure chamber, the maximum allowable force for a ring with an outer diameter of about 30 inches (76.2 cm) is 0.5 cm . 1 to 0 . It is preferably in the range of 4 kN, preferably about 0.4 kN . 25 kN. If the pressure chamber is pressurized with a pressure of, for example, 27 MPa, the maximum allowable force is 4 . 5-6 . 5 kN range, preferably about 5.5 kN . will be 0 kN. For diameters other than 30 inches (76.2 cm), the maximum allowable force can be determined prior to testing .

When a force is applied to the inner surface of the test ring, the pressure inside the pressure chamber can be approximately 0 MPa. Preferably, the test can be performed in a pressurized chamber so that pressure is applied to the outer cylindrical surface of the test ring. In this case, the test is performed with the pressure in the pressure chamber greater than 0 MPa, but less than the expected collapse pressure of the pipeline. The test can be performed at pressures in the pressure test chamber in the range of greater than 0 MPa and less than or equal to 30 MPa, preferably greater than about 0 MPa and less than or equal to 15 MPa. The pressure in the pressure chamber is between 0 and 0.00 of the expected collapse pressure of the pipeline . 7 times the expected collapse pressure, preferably 0.7 times the expected collapse pressure . 5 to 0 . It can be in the range of 7 times.

The results of the tests performed can be used to ascertain whether there is an acceptable binding force between the test device and the test ring. The restraining force depends on the shape of the ring, ie the diameter and width of the ring and the pressure in the pressure chamber. However, in some embodiments, the permissible binding force is 0.00 . It is in the range of 1 kN to 30 kN. If the pressure in the ring pressure chamber is about 0 MPa, preferably the allowable force is 0.5 psi . 1kN-0 . 4 kN range, preferably about 0.4 kN . was 2 kN. If the pressure in the chamber is about 27.5 . 6 MPa, preferably the acceptable restraining force is 4 . 5-6 . 5 kN range, preferably about 5.5 kN . was 0 kN.

Fluid is supplied to the ram to increase the force applied to the inner surface of the test ring. During the test, the rate of applied force was about 0.00 . 002 kN/min to about 0.002 kN/min . 04 kN/min. Preferably, the force is applied to the inner surface of the test ring for a period of 30 minutes to 4 hours, preferably 1-3 hours, more preferably 1-2 hours.

1 shows a pipeline of the type used for testing according to the invention; Figure 2 shows a cross-section of a test ring cut from the pipe of Figure 1; 1 shows a schematic diagram of a test device according to the invention; FIG. Figure 4 shows a cross-section on line BB of Figure 3, with the test apparatus set up in a test phase; 1 shows a schematic diagram of a test device with a test ring mounted therein; FIG. Fig. 4 shows a section on line BB of Fig. 3 set up in a preliminary stage; FIG. 10 shows a top view of the test apparatus and test ring set up in the preliminary stages; FIG. 2 shows a schematic diagram of the test apparatus and test ring set up in the preliminary stages. Three different pressure levels (a) 0 MPa, (b) 13 . 8 MPa, and (c) 27 . The results of extrusion tests performed at 6 MPa are shown. The graph shows time history results of frictional drag force and displacement, with Lino1 (48) and Lino2 (50) representing two separate position linear displacement transducers measuring the movement of the ring relative to the test apparatus. Three different pressures (a) 0 MPa, (b) 13 . 8 MPa, and (c) 27 . The results of extrusion tests performed at 6 MPa are shown. The graph shows the relationship between frictional drag force and lateral displacement of the ring, with Lino1 (48) and Lino2 (50) representing two separate position linear displacement transducers measuring the displacement of the ring.

Equivalent tests such as the "pressure collapse test" are tests in which a test ring specimen is subjected to increasing pressures to determine the pressure at which the ring collapses, e.g. Proceedings of the Twenty-fourth (2014) International Ocean and Polar Engineering Conference, vol . 2, p . means the test described in 88-95.

FIG. 1 shows a pipe 10 used in an undersea pipeline. A typical example is about 12 . 2 m, outer diameter 508 mm, wall thickness 35 mm. A test ring 12 (also shown in FIG. 2) is cut from one end of the pipe and has a typical length of 50 mm, ie greater than the wall thickness. After this length of ring has been cut, the pipe can still be used for pipeline construction. The end faces of the ring are machined to be substantially parallel and flat, i.e., smooth surfaces comparable to reality. Substantially flat and parallel means that the total ring length has a tolerance of ±0 . 01 mm. The roughness factor should not exceed ISO grade N6.

At regular time intervals, the needle pump injects small amounts of fluid into the ram chamber to increase the force applied to the test ring at a very slow rate. Preferably, the rate of displacement caused by an increase in force applied by the hydraulic ram is 0.5 . 01-0 . 05 mm/min, more preferably the rate of displacement is about 0.05 mm/min . 01-0 . 03 mm/min.

Preferably, the first phase of testing (S1) is performed over substantially the same period of time that the second phase of testing (S2) is performed. The pressure on the ram, and thus the force applied to the inner surface of the ring, can be increased over a period of about 30 minutes to about 4 hours, preferably over a period of about 1 to about 2 hours. The rate of force application by the hydraulic ram to the inner surface of the test ring was about 0.00 . 002 kN/min to about 0.002 kN/min . 04 kN/min.

When force is applied to the inner surface of the ring, pressure is maintained at a predetermined pressure within the pressure chamber. The first stage can be carried out at a pressure of 0 MPa in the chamber. Alternatively, the test can be performed with the chamber pressurized. The chamber can be pressurized to a pressure less than the expected collapse pressure. The test can be performed at a pressure in the pressure chamber of greater than 0 MPa and less than or equal to 30 MPa, preferably greater than about 0 MPa and less than or equal to 15 MPa, and more preferably greater than 0 MPa and less than or equal to 6 MPa. Preferably, the maximum pressure in the chamber that can be used in the test is 0.00% of the expected collapse pressure test . 5 to 0 . seven times.

(Example)
Three example pressures in the pressure chamber, 0, 13 . 8, and 27 . Using 6 MPa, D/t=20 . 5 steel test rings were tested. A test ring was cut from a pipe having an outside diameter of 32 inches (812.8 mm) and a wall thickness of 39 mm . The test ring length was 50 mm.

The pressure in the pressure chamber is, for example, 0, 13 . 8, and 27 . One of 6 MPa was applied first. The pressure in the ram was then slowly increased. The force exerted by the ram was measured, and lateral trunk movement of the ring was measured by two displacement transducers. Each test used a different steel ring and a new rubber sealing ring. Each test lasted approximately 120 minutes and the time and measured load on the ram were recorded. The velocity of the force was measured and was approximately 0.00 during the test . 002 kN/min to about 0.002 kN/min . It was made to rise to 04 kN/min.

The results are shown in FIGS. 9 and 10. FIG. The results show that the lateral restraining force (i.e. the ram force (52)) remains substantially constant after very small displacements of the steel ring relative to the sealing ring (approximately 0.1 mm) . was shown (FIG. 9). It has also been shown that the ram force is very small when no pressure is applied to the test apparatus. This confirms that the rubber seal ring is substantially deformed at the start of the pressure collapse test using this device. The resistance force exerted by the seal ring increases as the pressure applied to the test ring increases.

Claims (22)

Apparatus for testing rings cut from pipe used in the manufacture of submarine pipelines, comprising:
first and second test chamber portions that, when connected together, define a test chamber for containing the test ring;
sealing means for forming a seal against the ring when attached to the test chamber;
connecting said first and second test chamber portions together to form said test chamber and engaging said sealing means against said test ring when attached to said test chamber to means for forming a pressure-tight seal between the inner side and the outer side of said ring;
a fluid inlet in one of said test chamber portions for admitting pressurized fluid into said test chamber outside said test ring;
a hydraulic ram for applying a force to the inner surface of the test ring when mounted in the test chamber;
at least one sensor that measures the force exerted on the test ring by the hydraulic ram;
at least one sensor that measures movement of the test ring;
at least one sensor for measuring strain and deformation of said test ring. 2. The apparatus of claim 1, including means for pumping fluid to said hydraulic ram. 3. The apparatus of claim 2, wherein said means for pumping fluid to said hydraulic ram is a needle pump. Apparatus according to any one of the preceding claims, wherein said at least one sensor for measuring movement of said test ring is a displacement transducer. Apparatus according to any preceding claim, wherein the apparatus includes at least two sensors for measuring movement of the test ring relative to the test device. Apparatus according to any preceding claim, wherein the at least one sensor that measures the force exerted on the test ring by the hydraulic ram is a force meter. further comprising a spacer ring disposed between the first and second test chamber portions and used in the first and second test chamber portions to define the test chamber containing the test ring; A device according to any one of claims 1-6. A method for determining whether a test ring is correctly assembled in a test chamber for testing pipe used in the manufacture of an undersea pipeline, said test ring being the type of pipe used in the manufacture of said undersea pipeline. and having flat and substantially parallel surfaces at the ends of said test ring, said method comprising:
i) mounting the test ring to the pressure chamber such that opposite ends of the test ring form seals with opposing surfaces of the pressure chamber to isolate the interior of the test ring from the exterior;
ii) providing means for measuring the displacement of said test ring;
iii) providing means for measuring the force applied to the inner surface of said test ring;
iv) applying a force to the inner surface of said test ring;
v) measuring the displacement of the test ring to measure the force applied to the inner surface;
vi) using the displacement measurements and the force measurements to determine whether the test ring is properly installed in the pressure chamber. 9. A method according to claim 8, comprising ceasing the force applied to the inner surface of the test ring when the test ring has been displaced a predetermined distance, preferably a distance of about 1 mm. 10. A method according to claim 8 or 9, comprising providing a pressure in the pressure chamber greater than 0 MPa and less than an expected collapse pressure when applying force to the inner surface of the test ring. The method of any one of claims 8-10, wherein the method further comprises determining a range of allowable restraining forces prior to performing steps i)-v). The method of any one of claims 8-11, wherein the method further comprises holding the test ring within the pressure chamber and performing an external pressure collapse test on the test ring. The external pressure collapse test is
providing means for measuring strain and deformation of the test ring;
increasing the pressure on the outside of the test ring and measuring the strain and deformation of the test ring with increasing pressure;
13. The method of claim 12, comprising: determining an external collapse pressure of the test ring. Determining the external collapse pressure of the test ring determines the comparison of the pressure applied to the outside of the ring to the maximum strain measured to indicate the onset of accelerated nonlinear reduction in ring diameter with increasing pressure. 14. The method of claim 13, comprising detecting. A method of testing pipe for use in the manufacture of subsea pipelines comprising the steps of:
cutting rings from a pipe of the type used in the manufacture of said undersea pipeline;
forming flat, substantially parallel surfaces on the ends of said ring to provide a test ring;
attaching the test ring to the pressure chamber such that opposite ends of the test ring form a seal with opposing walls of the pressure chamber to isolate the inside of the test ring from the outside;
providing means for measuring the displacement of the test ring; providing means for measuring the force applied to the inner surface of the test ring;
applying a force to the inner surface of the test ring;
measuring the displacement of the test ring and measuring the force applied to the inner surface, and using the displacement measurement and the force measurement to verify that the test ring is properly assembled in the pressure chamber a step of determining whether
providing means for measuring strain and deformation of the test ring;
increasing the pressure on the outside of the test ring and measuring the strain and deformation of the test ring with increasing pressure;
determining a comparison of the pressure applied to the outside of the test ring to the maximum strain measured to detect the onset of acceleration of the non-linear decrease in test ring diameter with increasing pressure;
A method, including 16. Any one of claims 8-15, wherein applying a force to the inner surface of the test ring comprises applying the force until the force applied to the test ring exceeds a lateral resistance force. the method of. A method according to any one of claims 8 to 16, wherein applying a force to the inner surface of the test ring comprises providing means for applying a force to the inner surface of the test ring. 3. The step of providing means for applying a force to the inner surface of the test ring comprises providing a hydraulic ram, wherein the hydraulic ram is connected to a pump that supplies fluid to the hydraulic ram. 17. The method according to 17. The step of applying a force to the inner surface of said test ring comprises about 0.5 psi . 002 kN/min to about 0.002 kN/min . A method according to any one of claims 8 to 18, comprising applying force at a rate of 04 kN/min. 20. A method according to any one of claims 14 to 19, wherein the means for applying force to the inner surface of the test ring are removed from the test ring before the step of increasing the pressure on the outside of the test ring is performed. the method of. A method according to any one of claims 8-20, carried out using an apparatus according to any one of claims 1-7. Pipe testing apparatus for carrying out the method of any one of claims 8-21.