CN115078246B - Device and method for simulating full-size collision fatigue damage of deepwater pipeline - Google Patents

Abstract

The invention relates to a device for simulating full-size collision fatigue damage of a deepwater pipeline, which comprises: the air bag mechanism comprises an air bag and an air storage tank, the air storage tank is communicated with the air bag through an air duct, an air inlet valve is further arranged on the air duct, an air outlet valve is further arranged on the air bag, and the data and control acquisition system is electrically connected with the air inlet valve and the air outlet valve; pipeline and install pipeline staple bolt at pipeline both ends, the both ends pipeline staple bolt pass through fixed rope with mount pad fixed connection, control and data acquisition system control the inflation and the exhaust of gasbag and then control the rising and the decline of pipeline. The device for simulating the full-size collision fatigue damage of the deepwater pipeline uses gravity and buoyancy as power for longitudinal movement, realizes seabed self-positioning and automatic adjustment through the sensor, and can realize full-automatic seabed groove test.

Description

A device and method for simulating full-scale collision fatigue damage of deep-water pipeline

Technical Field

The invention relates to the technical field of offshore petroleum engineering, and in particular to a device and method for simulating full-scale collision fatigue damage of a deepwater pipeline.

Background Art

Steel catenary riser (SCR) is a widely used technology for deepwater and ultra-deepwater seabed natural gas and oil production. It has the advantages of simple structure, low cost, and can be integrated with various floating structures. For deepwater risers, the response to external forces becomes highly nonlinear. In addition, the periodic interaction between the SCR and the seabed leads to load concentration and may cause severe fatigue damage because the curvature and bending moment change significantly in the area called the landing zone. Different numerical methods have been developed to establish the overall structure of the SCR and study its dynamic behavior. Submarine pipelines are widely used in the development of marine oil and gas resources as offshore transportation. The part of the submarine pipeline connected from the oil platform to the submarine pipeline will contact the seabed. With the continuous movement of the offshore platform, the depth of the groove at the contact point of the submarine pipeline will increase over time, resulting in greater forces on the pipeline and reducing the stability of the pipeline. In the past few decades, researchers have studied the groove formation process at the contact point of the submarine pipeline physically and numerically. However, in the actual operation of the pipeline, the seabed is subjected to the combined action of water and pipeline. This complex process is difficult to achieve with numerical simulation methods, and analysis is performed to determine the shape and range of the SCR groove.

Summary of the invention

In view of the above problems, the purpose of the present invention is to provide a device and method for simulating full-scale collision fatigue damage of deep-water pipelines, which can simulate the formation of grooves at the touchdown point during pipeline operation, and simulate the wear caused by the cyclic impact of the pipeline on the seabed. It can simulate the fatigue life of the pipeline under the action of cyclic soil interaction force, and determine the deformation of pipe fittings under real harsh conditions, thereby providing real data and experimental accumulation for the design of pipeline touchdown points, and at the same time provide a design guide for the laying and safety defense of deep-water oil and gas pipelines in actual engineering construction.

To achieve the above object, the present invention adopts the following technical solutions:

In one aspect, the present invention provides a device for simulating full-scale collision fatigue damage of a deepwater pipeline, comprising:

A mounting seat and an airbag mechanism and a control and data acquisition system mounted on the mounting seat, wherein the airbag mechanism includes an airbag and an air storage tank, the air storage tank is connected to the airbag through an air guide tube, the air guide tube is also provided with an air intake valve, the airbag is also provided with an exhaust valve, the data and control acquisition system is electrically connected to the air intake valve and the exhaust valve, and the control and data acquisition system is used to control the inflation and exhaust of the airbag;

A pipeline and pipeline clamps installed at both ends of the pipeline, the pipeline clamps at both ends are fixedly connected to the mounting seat through fixing ropes, and the control and data acquisition system controls the inflation and exhaust of the airbag and thus controls the rise and fall of the pipeline.

Furthermore, the device for simulating full-scale collision fatigue damage of a deepwater pipeline also includes two laser rangefinders and propellers installed on the pipeline clamps at both ends. The two laser rangefinders are respectively fixedly installed on both sides of the control and data acquisition system to detect whether the two ends of the pipeline are deflected during the experiment, and send the detection information to the control and data acquisition system. The control and data acquisition system controls the rotation of the propellers at both ends according to the detection information.

Furthermore, the device for simulating full-scale collision fatigue damage of a deepwater pipeline also includes a displacement sensor, which is used to detect the distance between the control and data acquisition system and the pipeline. If the distance is shortened, the air intake valve is controlled to open, otherwise the air intake valve is controlled to close.

Furthermore, the device for simulating full-scale collision fatigue damage of a deepwater pipeline also includes an experimental pipeline positioning system installed on the pipeline clamp, which is used to detect the distance between the pipeline and the seabed.

Furthermore, it also includes a rope fixing shaft, which is fixedly connected to the control and data acquisition system, and the top end of the fixing rope is fixedly connected to the rope fixing shaft.

Furthermore, the gas storage tanks include two, the two gas storage tanks are connected to the airbags respectively through an air duct, each of the air ducts is provided with a control valve, and the two control valves are electrically connected to the control and data acquisition system.

Furthermore, the two propellers are respectively installed on opposite sides of the two ends of the pipeline.

On the other hand, the technical solution of the present invention provides a method for simulating full-scale collision fatigue damage of a deepwater pipeline, based on the device for simulating full-scale collision fatigue damage of a deepwater pipeline, comprising the steps of:

Step 1: Control the opening of the exhaust valve to allow the pipeline to sink until it contacts the seabed;

Step 2, the displacement sensor detects the distance between the pipeline and the control and data acquisition system in real time. If the detection distance is shortened, the exhaust valve is controlled to be closed and the intake valve is controlled to be opened to make the pipeline float;

Repeat steps 1 and 2 until the end of the experiment.

Furthermore, the method further comprises the steps of:

Step 3: Control the laser rangefinder to detect in real time whether the pipeline is offset. If so, control the propellers on both sides of the pipeline to rotate so that the pipeline returns to its initial position. If not, control steps 1 and 2 to be repeated until the end of the experiment.

The present invention adopts the above technical solution, which has the following advantages:

The present invention can simulate the effect of seabed soil on steel pipes in deep water environment. Existing devices can usually only simulate in laboratory water pools, and the soil depth and water flow velocity are different from the real environment, and the accuracy of the test results is questionable. The present invention can realize the test on the real seabed, and the test site is the real pipeline laying environment, and the test results are reliable.

The present invention can realize fully automatic deep-sea testing. Most of the existing devices need to rely on the elevator on the hull for longitudinal movement, and the power of the device depends on the power supply of external cables, which is not suitable for deep sea. The system relies on gravity and buoyancy as the power of longitudinal movement, realizes seabed self-positioning and automatic adjustment through sensors, and can realize fully automatic seabed trench testing.

The present invention can test the fatigue limit of a pipeline under the interaction force between the seabed and the soil. Existing simulation technology can only simulate rigid pipelines to predict the formation of grooves at the contact point, but cannot simulate the fatigue limit of the pipeline. Existing test devices can only simulate the interaction between a pipeline without deflection and the soil. This experimental device can simulate the dynamic response of the pipeline under the action of the seabed soil in a bent state.

The present invention takes the installation, testing and unloading processes into consideration, and utilizes a high-pressure airbag in the test device to balance gravity and buoyancy, which greatly facilitates the installation process. It also has a self-positioning function, which reduces test errors and greatly facilitates the installation of the test device, thereby improving the accuracy of the test.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Throughout the accompanying drawings, the same reference numerals are used to represent the same components. In the accompanying drawings:

FIG1 is a schematic diagram of the structure of a device for simulating full-scale collision fatigue damage of a deepwater pipeline;

FIG2 is a state view of the airbag deployment of the device simulating full-scale collision fatigue damage of a deep-water pipeline;

FIG3 is a structural view of an airbag mechanism of a device for simulating full-scale collision fatigue damage of a deepwater pipeline;

FIG4 is a schematic diagram of the structure of a control and data acquisition system;

FIG. 5 is a schematic diagram of the structure of the pipe clamp installed at one end of the pipe in FIG. 1 and the propeller on the pipe clamp.

DETAILED DESCRIPTION

The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

An embodiment of the present invention provides a device for simulating full-scale collision fatigue damage of a deepwater pipeline. The device relies on gravity and buoyancy as the driving force for longitudinal movement, realizes seabed self-positioning and automatic adjustment through sensors, and can realize fully automatic seabed trench testing.

Example 1

As shown in Figures 1 to 5, the device for simulating full-scale collision fatigue damage of deep-water pipelines includes a mounting seat 9, an airbag mechanism and a control and data acquisition system installed on the mounting seat 9, a pipeline 8, and a pipeline clamp 18 installed at both ends of the pipeline 8. The airbag mechanism includes an airbag 1 and an air tank 2. The air tank 2 is connected to the airbag 1 through an air guide pipe 12. The air guide pipe 12 is also provided with an air intake valve 11. The airbag 1 is also provided with an exhaust valve (not shown in the figure). The data and control acquisition system 3 is electrically connected to the air intake valve 11 and the exhaust valve. The control and data acquisition system 2 is used to control the inflation and exhaust of the airbag 1. The pipeline clamps 18 at both ends are fixedly connected to the mounting seat 9 through fixed ropes 17. The control and data acquisition system 3 controls the inflation and exhaust of the airbag 1 and thus controls the rise and fall of the pipeline 8.

When the test starts, the control and data acquisition system 8 controls the air inlet valve 11 to open, allowing gas to enter the airbag 1 through the air guide tube 12, so that the airbag 1 can expand rapidly. When the airbag 1 becomes larger, the buoyancy of the device under water increases, and it will float upward.

When the device needs to move downward, the control and data acquisition system 3 controls the air inlet valve 11 of the airbag 1 to close, so that the gas cannot enter through the valve, while the gas in the airbag 1 can be discharged to the outside through the exhaust valve.

The control and data acquisition system 3 may be connected to the intake valve 11 and the exhaust valve by a data line 10 or by radio connection.

Therefore, the simulation experiment device provided by the present invention does not need to rely on an external power source, and can achieve repeated interaction between the pipeline and the seabed by only using the gravity and buoyancy of the device itself, thereby obtaining the fatigue limit of the test pipeline under the seabed circulation pipe-soil interaction force and the formation of grooves. In addition, the pipeline 8 in the present invention can be a curved pipeline or a straight pipeline, which can simulate the dynamic response of the pipeline under the action of the seabed soil in a curved state, and the experimental results are more reliable.

It should be noted that in order to improve the reliability of the experiment, the gas tank 2 can be configured to include two, and the two gas tanks 2 are connected to the airbag 1 through an air guide tube 12, each of which is provided with an air intake valve 11, and the two air intake valves 11 are electrically connected to the control and data acquisition system 2. When one of the gas tanks 2 fails to supply gas, the other gas tank 2 works, thereby ensuring the reliability of the experiment.

Furthermore, in order to improve the reliability of the experiment and prevent the pipeline 8 from deflecting during the rising or descending process, the device for simulating full-scale collision fatigue damage of a deep-water pipeline also includes two laser rangefinders 15 and propellers 19 installed on the pipeline clamps 18 at both ends. The two laser rangefinders 18 are respectively fixedly installed on both sides of the control and data acquisition system 3 to detect whether the two ends of the pipeline 8 are deflected during the experiment, and send the detection information to the control and data acquisition system 3. The control and data acquisition system 3 controls the rotation of the propellers 19 at both ends according to the detection information.

The two propellers 19 are respectively installed on opposite sides of the two ends of the pipeline 8.

When the laser rangefinder 18 detects that the pipeline is deflected clockwise or counterclockwise, the pipeline 8 is restored to its initial position by simultaneously controlling the spirals 19 at both ends to rotate clockwise or counterclockwise, thereby further improving the reliability of the experiment.

The device for simulating full-scale collision fatigue damage of deep-water pipelines also includes a displacement sensor 5, which is used to detect the distance between the control and data acquisition system 3 and the pipeline 8. If the distance is shortened, the air intake valve 11 is controlled to open, otherwise the air intake valve is controlled to close.

If the displacement sensor 5 detects that the distance between the control and data acquisition system 3 and the pipeline 8 is shortened, it means that the pipeline 8 has penetrated into the seabed to form a groove. Then, the device is floated by inflating the airbag 1 and repeated fatigue tests are performed.

The device for simulating full-scale collision fatigue damage of a deepwater pipeline further comprises an experimental pipeline positioning system 4 installed on the pipeline clamp 18, which is used to detect the distance between the pipeline and the seabed.

When the experimental pipeline positioning system 4 detects that the distance between the pipeline 8 and the seabed 6 is exactly 0, it means that the lowest point of the pipeline 8 just touches the seabed. At the same time, when the displacement sensor 5 detects that the distance between the control and data acquisition system 3 and the pipeline 8 is shortened, it means that the pipeline has penetrated into the seabed to form a groove. Then, the device is floated by inflating the airbag 1 and repeated fatigue experiments are carried out.

It should be noted here that the displacement sensor 5 can be installed on the mounting seat 9 or on the control and data acquisition system 3 .

The device for simulating full-scale collision fatigue damage of deep-water pipelines also includes a rope fixing shaft 13, which is fixedly connected to the control and data acquisition system 3, and the top end of the fixing rope 17 is fixedly connected to the rope fixing shaft 13.

The device for simulating full-scale collision fatigue damage of deepwater pipelines also includes a displacement sensor processor 14, which is fixedly installed between the control and data acquisition system 3 and the rope fixing shaft 13. The laser rangefinder 15 measures the distance between the device and the seabed by laser, and transmits data to the displacement sensor processor 14. The displacement sensor processor 14 transmits the processed signal to the control and data acquisition integrated system 16, and controls the opening and closing of the valve through the data line 10 to control the longitudinal movement of the device.

Another embodiment of the present invention further provides a method for simulating full-scale collision fatigue damage of a deepwater pipeline, based on the device for simulating full-scale collision fatigue damage of a deepwater pipeline, comprising the steps of:

Step 1: Control the opening of the exhaust valve to allow the pipeline 8 to sink until it contacts the seabed 6;

Step 2, the displacement sensor 5 detects the distance between the pipeline 8 and the control and data acquisition system 3 in real time. If the detection distance is shortened, the exhaust valve is controlled to be closed and the intake valve 11 is opened to make the pipeline 8 float;

Step 3: Control the laser rangefinder 15 to detect in real time whether the pipeline 8 is offset. If yes, control the propellers 19 on both sides of the pipeline to rotate so that the pipeline 8 returns to its initial position. If no, control to repeat steps 1 and 2 until the end of the experiment. According to the cycle time and speed of the rigid catenary riser, set the valve intake and exhaust speeds to be the same and Δv. The calculation method of Δv is:

If the riser movement cycle time under real sea conditions is Ts, the up and down movement distance is 2D, and D is the pipe diameter, then it can be seen that the pipe running speed changes with time as follows:

The device acceleration a is

The airbag inflation speed Δv is

Where m is the total weight of the device, ρ is the density of seawater, and g is the acceleration due to gravity.

The present invention provides a device and method for simulating full-scale collision fatigue damage of deep-water pipelines, which can simulate the effect of seabed soil on steel pipes in deep-water environments. Existing devices can usually only be simulated in laboratory water pools. The soil depth and water flow velocity are different from the real environment, and the accuracy of the test results is questionable. The present invention can realize the test on the real seabed, and the test site is the real pipeline laying environment, so the test results are reliable. The present invention can realize fully automatic deep-sea testing. Most of the existing devices need to rely on the elevator on the hull for longitudinal movement, and the power of the device depends on the power supply of external cables, which is not suitable for deep sea. This system relies on gravity and buoyancy as the power for longitudinal movement, and realizes seabed self-positioning and automatic adjustment through sensors, which can realize fully automatic seabed trench testing.

The present invention can test the fatigue limit of a pipeline under the interaction force between the seabed and the soil. Existing simulation technology can only simulate rigid pipelines to predict the formation of grooves at the contact point, but cannot simulate the fatigue limit of the pipeline. Existing test devices can only simulate the interaction between a pipeline without deflection and the soil. This experimental device can simulate the dynamic response of the pipeline under the action of the seabed soil in a bent state.

The present invention takes the installation, testing and unloading processes into consideration, and utilizes a high-pressure airbag in the test device to balance gravity and buoyancy, which greatly facilitates the installation process. It also has a self-positioning function, which reduces test errors and greatly facilitates the installation of the test device, thereby improving the accuracy of the test.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (7)

1. A device for simulating full-scale collision fatigue damage of deep-water pipelines, characterized by comprising: A mounting seat and an airbag mechanism and a control and data acquisition system mounted on the mounting seat, wherein the airbag mechanism includes an airbag and an air storage tank, the air storage tank is connected to the airbag through an air guide tube, the air guide tube is also provided with an air intake valve, the airbag is also provided with an exhaust valve, the data and control acquisition system is electrically connected to the air intake valve and the exhaust valve, and the control and data acquisition system is used to control the inflation and exhaust of the airbag; A pipeline and pipeline clamps installed at both ends of the pipeline, wherein the pipeline clamps at both ends are fixedly connected to the mounting seat through fixing ropes, and the control and data acquisition system controls the inflation and exhaust of the airbag to control the rise and fall of the pipeline; The device for simulating full-scale collision fatigue damage of a deepwater pipeline further comprises a displacement sensor, wherein the displacement sensor is used to detect the distance between the control and data acquisition system and the pipeline, and if the distance is shortened, the air intake valve is controlled to be opened, otherwise, the air intake valve is controlled to be closed; The device for simulating full-scale collision fatigue damage of a deepwater pipeline also includes an experimental pipeline positioning system installed on the pipeline clamp, which is used to detect the distance between the pipeline and the seabed. 2. The device for simulating full-scale collision fatigue damage of a deepwater pipeline according to claim 1 is characterized in that the device for simulating full-scale collision fatigue damage of a deepwater pipeline also includes two laser rangefinders and propellers installed on the pipeline clamps at both ends, and the two laser rangefinders are respectively fixedly installed on both sides of the control and data acquisition system to detect whether the two ends of the pipeline are deflected during the experiment, and send the detection information to the control and data acquisition system, and the control and data acquisition system controls the rotation of the propellers at both ends according to the detection information. 3. The device for simulating full-scale collision fatigue damage of a deepwater pipeline according to claim 1 is characterized in that it also includes a rope fixing shaft, the rope fixing shaft is fixedly connected to the control and data acquisition system, and the top end of the fixing rope is fixedly connected to the rope fixing shaft. 4. The device for simulating full-scale collision fatigue damage of a deepwater pipeline according to claim 1 is characterized in that the gas storage tanks include two, the two gas storage tanks are connected to the airbags respectively through an air guide tube, each of the air guide tubes is provided with a control valve, and the two control valves are electrically connected to the control and data acquisition system. 5. The device for simulating full-scale collision fatigue damage of a deepwater pipeline according to claim 2, characterized in that the two propellers are respectively installed on opposite sides of the two ends of the pipeline. 6. A method for simulating full-scale collision fatigue damage of a deepwater pipeline, based on the device for simulating full-scale collision fatigue damage of a deepwater pipeline according to any one of claims 1 to 5, characterized in that it comprises the steps of: Step 1: Control the opening of the exhaust valve to allow the pipeline to sink until it contacts the seabed; Step 2, the displacement sensor detects the distance between the pipeline and the control and data acquisition system in real time. If the detection distance is shortened, the exhaust valve is controlled to be closed and the intake valve is controlled to be opened to make the pipeline float; Repeat steps 1 and 2 until the end of the experiment. 7. The method for simulating full-scale collision fatigue damage of a deepwater pipeline according to claim 6, characterized in that it also includes the steps of: Step 3, control the laser rangefinder to detect in real time whether the pipeline is offset. If so, control the propellers on both sides of the pipeline to rotate so that the pipeline returns to its initial position. If not, control to repeat steps 1 and 2 until the end of the experiment.