Sensing device and method for monitoring deformation stress of deep-sea pipeline

Abstract

The present invention discloses a sensing device and method for monitoring deformation stress of deep-sea pipelines. The sensing device includes a housing, a differential pressure sensor, a sensing probe, and a connecting pipe. The beneficial technical effect of the present invention is as follows: a sensing device and method for monitoring deformation stress of deep-sea pipelines are proposed. This scheme can eliminate the influence of the background static pressure caused by the deep-sea water body on the detection signal, enabling us to measure tiny deformation stress under high water pressure conditions in the deep sea.

Description

Technical Field

[0001] The present invention relates to a deep-sea pipeline online monitoring technology, and in particular to a sensing device and method for monitoring the deformation stress of a deep-sea pipeline. Background Art

[0002] As marine economic development gradually moves deeper into the deep sea, the demand for deep-sea structure monitoring continues to increase. Dynamic and static deformation stresses are gaining increasing attention because they are directly related to structural health and fatigue failure. Typical application scenarios include deep-sea oil and gas pipelines, FPSO oil and gas production platforms and their steel catenary risers (SCRs), and underwater cables used in deep-sea or offshore wind power platforms.

[0003] Currently, two common methods for detecting structural deformation in deep-sea environments are regular ROV inspections and fiber optic sensing. While regular ROV inspections don't require infrastructure, they can't achieve online, real-time monitoring and incur high labor and maintenance costs. While fiber optic sensing can achieve online, real-time monitoring, it carries high construction and equipment costs. More importantly, fiber optic sensing systems are significantly affected by vibration, making them unable to accurately measure deformation stress in dynamic environments. They are also susceptible to the influence of underwater currents and internal waves, resulting in a high false alarm rate.

[0004] The deformation and deformation stress detection methods used on land are mainly based on piezoelectric materials or strain materials. However, in the deep sea with high static pressure, land-based detection methods will be affected by the background water pressure and cannot measure tiny deformation stress. Summary of the Invention

[0005] In response to the problems in the background technology, the present invention proposes a sensing device for monitoring deformation stress of deep-sea pipelines. The innovation of the sensing device is that: the sensing device includes a housing, a differential pressure sensor, a sensing probe and a connecting pipe;

[0006] The differential pressure sensor is encapsulated in a housing;

[0007] The sensing probe is composed of a sensing hard tube and a pressure guiding tube; the sensing hard tube is a single-port tube, the port of the sensing hard tube is connected to the outer port of the pressure guiding tube, and the inner port of the pressure guiding tube is connected to the first input port of the differential pressure sensor; the sensing hard tube is placed outside the housing; the sensing hard tube and the pressure guiding tube are filled with liquid pressure guiding medium; the housing is provided with a first through hole matching the pressure guiding tube, and the middle part of the pressure guiding tube is connected to the first through hole through connector 1;

[0008] The inner port of the connecting tube is connected to the second input port of the differential pressure sensor, and the outer port of the connecting tube is placed outside the shell; a second through hole matching the connecting tube is provided on the shell, and the middle part of the connecting tube is connected to the second through hole through connector 2.

[0009] The role of the housing is to isolate the seawater, bear the deep sea pressure, and protect the differential pressure sensor. In specific implementation, it should be made of a material with a certain strength and resistance to seawater corrosion;

[0010] The sensor probe is fixed on the structure to sense the deformation of the structure. When the structure deforms, the sensor probe is also forced to deform, thereby changing the pressure of the internal liquid pressure-conducting medium.

[0011] The pressure guiding pipe is used to connect the sensing probe and the first input port of the differential pressure sensor;

[0012] The connecting pipe is used to connect the external environmental water body and the second input port of the differential pressure sensor;

[0013] The differential pressure sensor is used to obtain the pressure difference sensed by the first input port and the second input port.

[0014] The connector has the functions of sealing, connecting and supporting, and can be selected from the existing technologies.

[0015] Preferably, the sensing hard tube is made of titanium-based metal, high silicon cast iron or vulcanized rubber.

[0016] Based on the aforementioned sensing device, the present invention further proposes a method for monitoring deformation stress of a deep-sea pipeline. The hardware involved includes multiple sensing devices and a processing device. The structure of a single sensing device is as described above, and the outputs of multiple differential pressure sensors are connected to the processing device via electrical cables. The specific method is as follows: the deep-sea pipeline is formed by connecting multiple pipes; the method includes:

[0017] 1) A sensing device is installed at the connection between every two adjacent pipelines. When a single sensing device is installed, the sensing hard tube is installed on the outer wall of the deep-sea pipeline corresponding to the interface between the two pipelines. The sensing hard tube intersects with the plane where the interface between the two pipelines is located. The left section of the sensing hard tube is fixed to the outer wall of the deep-sea pipeline by a first clamp, and the right section of the sensing hard tube is fixed to the outer wall of the deep-sea pipeline by a second clamp. The interface between the two pipelines is located between the first clamp and the second clamp. The housing is fixed to the outer wall of the deep-sea pipeline.

[0018] 2) After being put into operation, the processing device periodically identifies the output signals of each differential pressure sensor. If the output signal of the differential pressure sensor exceeds the set threshold, it indicates that the deep-sea pipeline has deformed at the corresponding part.

[0019] Traditional deformation and deformation stress detection methods mainly use piezoelectric materials or strain materials, which are not suitable for deep-sea conditions with great depth and high static pressure. The main reason is that under deep-sea conditions, the detection signals that can be obtained by traditional methods include the background static pressure caused by the deep-sea water body, sensor noise and the actual strain of the structure. Since the background static pressure caused by the deep-sea water body is much larger than the actual strain of the structure (usually, the deformation process of deep-sea pipelines is relatively slow, and the stress changes are also slow), and the sensor noise is proportional to the background static pressure, this will cause the sensor noise to be close to the actual strain of the structure, thereby seriously affecting the dynamic range and accuracy of the sensing device.

[0020] The idea behind the aforementioned method for monitoring deformation and stress of deep-sea pipelines is that when a deep-sea pipeline deforms under external forces, deformation usually occurs first at the connection between adjacent pipelines due to the good structural strength of a single pipeline. Therefore, the present invention places the sensing hard tube at the pipeline interface.

[0021] When a sensing device is put into operation, if the corresponding pipe connection does not deform, the signal corresponding to the first input port measured by the differential pressure sensor is "background static pressure A + sensor noise A". At the same time, the signal corresponding to the second input port is "background static pressure B + sensor noise B". Since the sensing hard pipe, pressure pipe and connecting pipe are all at the same depth in the sea, the background static pressure caused by the water pressure is the same. Therefore, "background static pressure A = background static pressure B". Since it is the same differential pressure sensor, the sensor noise corresponding to the two input ports is the same, so "sensor noise A = sensor noise B". At this time, through the processing of the differential pressure sensor, the signals corresponding to the two input ports cancel each other out, and the final output signal is "0";

[0022] When deformation occurs at the corresponding pipeline connection, the left and right sections of the sensing tube, fixed to the outer walls of the pipeline on either side of the interface by two clamps, will move with the pipelines on either side of the interface, causing the sensing tube to deform and squeezing the liquid pressure-conducting medium within it. At this time, the signal corresponding to the first input port measured by the differential pressure sensor is "background static pressure A + sensor noise A + sensor induced force" (the sensor induced force is the force generated by the squeezing of the liquid pressure-conducting medium). The signal corresponding to the second input port is still "background static pressure B + sensor noise B." As mentioned above, because the background static pressure and sensor noise corresponding to the two input ports cancel each other out, the final output signal of the differential pressure sensor is the "sensor induced force." Based on the "sensor induced force" and its value, we can determine whether the corresponding part is deformed and the severity of the deformation, realizing online real-time monitoring of deep-sea pipelines. After adopting the solution of the present invention, the background static pressure and sensor noise caused by deep-sea high water pressure can be self-cancelled, solving the problem that the existing technology cannot measure tiny deformation stress under deep-sea high water pressure conditions.

[0023] Preferably, the deep-sea pipeline is an oil pipeline, a gas pipeline, a steel catenary riser or an underwater cable.

[0024] In addition, in some application scenarios, the deep-sea pipeline includes a main pipe and multiple branch pipes. For the connection between the main pipe and the branch pipe, the present invention also proposes a method for monitoring the deformation stress at the bifurcation of the deep-sea pipeline. In this scheme, the sensing hard pipe is set to L shape, and the connection between the main pipe and the branch pipe forms a monitoring point. A sensing device is set at each monitoring point; when a single sensing device is set, the vertical section of the sensing hard pipe is fixed to the outer wall of the branch pipe through the first clamp, and the horizontal section of the sensing hard pipe is fixed to the outer wall of the main pipe through the second clamp; the shell is fixed On the outer wall of the deep-sea pipeline; similar to the principle of the previous method, since the vertical section and horizontal section of the sensing rigid tube are fixed on the main pipe and the branch pipe respectively, when the connection between the main pipe and the branch pipe is bent, the vertical section and horizontal section of the sensing rigid tube will move with the main pipe and the branch pipe respectively, thereby causing the sensing rigid tube to deform, resulting in a change in the stress state of the liquid pressure-conducting medium in the sensing rigid tube. Based on the output signal of the differential pressure sensor, we can know whether the corresponding bifurcation on the deep-sea pipeline has deformed and the severity of the deformation.

[0025] The beneficial technical effect of the present invention is: a sensing device and method for monitoring the deformation stress of deep-sea pipelines are proposed. This scheme can eliminate the influence of the background static pressure caused by the deep-sea water body on the detection signal, enabling us to measure tiny deformation stress under high water pressure conditions in the deep sea. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1, a schematic structural diagram of the sensing device of the present invention;

[0027] Figure 2 、Usage status of the present invention Figure 1 (The sensing device is arranged at the junction of adjacent pipes; the dotted line in the figure represents the pipe interface);

[0028] Figure 3 、Usage status of the present invention Figure 2 ( Figure 2 The parts shown are in a deformed state);

[0029] Figure 4 、Usage status of the present invention Figure 3 (The sensing device is arranged at the connection between the main pipe and the branch pipe);

[0030] Figure 5 、Usage status of the present invention Figure 4 ( Figure 4 The parts shown are in a deformed state);

[0031] The names corresponding to the various marks in the figure are: housing 1, differential pressure sensor 2, sensing hard tube 3, pressure guiding tube 4, and connecting tube 5. DETAILED DESCRIPTION

[0032] A sensing device for monitoring deformation stress of deep-sea pipelines, the innovation of which is that: the sensing device includes a housing 1, a differential pressure sensor 2, a sensing probe and a connecting pipe 5;

[0033] The differential pressure sensor 2 is encapsulated in the housing 1;

[0034] The sensing probe is composed of a sensing hard tube 3 and a pressure guiding tube 4; the sensing hard tube 3 is a single-port tube, the port of the sensing hard tube 3 is connected to the outer port of the pressure guiding tube 4, and the inner port of the pressure guiding tube 4 is connected to the first input port of the differential pressure sensor 2; the sensing hard tube 3 is placed outside the housing 1; the sensing hard tube 3 and the pressure guiding tube 4 are filled with a liquid pressure guiding medium; the housing 1 is provided with a first through hole matching the pressure guiding tube 4, and the middle part of the pressure guiding tube 4 is connected to the first through hole through a connector 1;

[0035] The inner port of the connecting tube 5 is connected to the second input port of the differential pressure sensor 2, and the outer port of the connecting tube 5 is placed outside the shell 1; a second through hole matching the connecting tube 5 is provided on the shell 1, and the middle part of the connecting tube 5 is connected to the second through hole through connector 2.

[0036] Furthermore, the material of the sensing hard tube 3 is titanium-based metal, high silicon cast iron or vulcanized rubber.

[0037] A method for monitoring deformation stress of deep-sea pipelines, the hardware involved includes multiple sensing devices and processing devices; a single sensing device includes a housing 1, a differential pressure sensor 2, a sensing probe and a connecting pipe 5;

[0038] The differential pressure sensor 2 is encapsulated in the housing 1;

[0039] The sensing probe is composed of a sensing hard tube 3 and a pressure guiding tube 4; the sensing hard tube 3 is a single-port tube, the port of the sensing hard tube 3 is connected to the outer port of the pressure guiding tube 4, and the inner port of the pressure guiding tube 4 is connected to the first input port of the differential pressure sensor 2; the sensing hard tube 3 is placed outside the housing 1; the sensing hard tube 3 and the pressure guiding tube 4 are filled with a liquid pressure guiding medium; the housing 1 is provided with a first through hole matching the pressure guiding tube 4, and the middle part of the pressure guiding tube 4 is connected to the first through hole through a connector 1;

[0040] The inner port of the connecting tube 5 is connected to the second input port of the differential pressure sensor 2, and the outer port of the connecting tube 5 is placed outside the housing 1; the housing 1 is provided with a second through hole matching the connecting tube 5, and the middle part of the connecting tube 5 is connected to the second through hole through the second connector;

[0041] The outputs of the plurality of differential pressure sensors 2 are connected to the processing device via electrical cables;

[0042] The innovation lies in that the deep-sea pipeline is formed by connecting multiple pipelines; the method includes:

[0043] 1) A sensing device is installed at the connection between every two adjacent pipelines. When a single sensing device is installed, the sensing rigid tube 3 is installed on the outer wall of the deep-sea pipeline corresponding to the interface between the two pipelines. The sensing rigid tube 3 intersects with the plane where the interface between the two pipelines is located. The left section of the sensing rigid tube 3 is fixed to the outer wall of the deep-sea pipeline by a first clamp, and the right section of the sensing rigid tube 3 is fixed to the outer wall of the deep-sea pipeline by a second clamp. The interface between the two pipelines is located between the first clamp and the second clamp. The housing 1 is fixed to the outer wall of the deep-sea pipeline. In specific implementation, before the deep-sea pipeline is laid and submerged in the sea, the sensing device is installed on the deep-sea pipeline, and then the deep-sea pipeline and the sensing device are submerged in the sea together.

[0044] 2) After being put into operation, the processing device periodically identifies the output signals of each differential pressure sensor 2. If the output signal of the differential pressure sensor 2 exceeds the set threshold, it indicates that the deep-sea pipeline has deformed at the corresponding position.

[0045] Furthermore, the deep-sea pipeline is an oil pipeline, a gas pipeline, a steel catenary riser or an underwater cable.

[0046] A method for monitoring deformation stress at a deep-sea pipeline bifurcation, the hardware involved includes multiple sensing devices and processing devices; a single sensing device includes a housing 1, a differential pressure sensor 2, a sensing probe, and a connecting pipe 5;

[0047] The differential pressure sensor 2 is encapsulated in the housing 1;

[0048] The sensing probe is composed of a sensing hard tube 3 and a pressure guiding tube 4; the sensing hard tube 3 is a single-port tube, the port of the sensing hard tube 3 is connected to the outer port of the pressure guiding tube 4, and the inner port of the pressure guiding tube 4 is connected to the first input port of the differential pressure sensor 2; the sensing hard tube 3 is placed outside the housing 1; the sensing hard tube 3 and the pressure guiding tube 4 are filled with a liquid pressure guiding medium; the housing 1 is provided with a first through hole matching the pressure guiding tube 4, and the middle part of the pressure guiding tube 4 is connected to the first through hole through a connector 1;

[0049] The inner port of the connecting tube 5 is connected to the second input port of the differential pressure sensor 2, and the outer port of the connecting tube 5 is placed outside the housing 1; the housing 1 is provided with a second through hole matching the connecting tube 5, and the middle part of the connecting tube 5 is connected to the second through hole through the second connector;

[0050] The outputs of the plurality of differential pressure sensors 2 are connected to the processing device via electrical cables;

[0051] The innovation lies in that: the sensing hard pipe 3 is L-shaped; the deep-sea pipeline includes a main pipe and multiple branch pipes connected to the main pipe; the method includes:

[0052] 1) The connection between the main pipe and the branch pipe forms a monitoring point, and a sensing device is installed at each monitoring point. When installing a single sensing device, the vertical section of the sensing hard pipe 3 is fixed to the outer wall of the branch pipe through a first clamp, and the horizontal section of the sensing hard pipe 3 is fixed to the outer wall of the main pipe through a second clamp. The housing 1 is fixed to the outer wall of the deep-sea pipeline.

[0053] 2) After being put into operation, the processing device periodically identifies the output signals of each differential pressure sensor 2. If the output signal of the differential pressure sensor 2 exceeds the set threshold, it indicates that the deep-sea pipeline has deformed at the corresponding position.

[0054] Furthermore, the deep-sea pipeline is an oil pipeline, a gas pipeline, a steel catenary riser or an underwater cable.

Claims

1. A method for monitoring deformation stress of a deep-sea pipeline, the hardware involved comprising a plurality of sensing devices and a processing device; a single sensing device comprising a housing (1), a differential pressure sensor (2), a sensing probe and a connecting pipe (5); The differential pressure sensor (2) is encapsulated in the housing (1); The sensing probe is composed of a sensing hard tube (3) and a pressure-guiding tube (4); the sensing hard tube (3) is a single-port tube, the port of the sensing hard tube (3) is connected to the outer port of the pressure-guiding tube (4), and the inner port of the pressure-guiding tube (4) is connected to the first input port of the differential pressure sensor (2); the sensing hard tube (3) is placed outside the housing (1); the sensing hard tube (3) and the pressure-guiding tube (4) are filled with a liquid pressure-guiding medium; a first through hole matching the pressure-guiding tube (4) is provided on the housing (1), and the middle of the pressure-guiding tube (4) is connected to the first through hole through a connector 1; The inner port of the connecting tube (5) is connected to the second input port of the differential pressure sensor (2), and the outer port of the connecting tube (5) is placed outside the housing (1); a second through hole matching the connecting tube (5) is provided on the housing (1), and the middle portion of the connecting tube (5) is connected to the second through hole via a second connector; The output parts of the plurality of differential pressure sensors (2) are connected to the processing device via electrical cables; Its characteristics are: The deep-sea pipeline is formed by connecting multiple pipelines; the method includes: 1) A sensing device is provided at the connection between every two adjacent pipelines; when a single sensing device is provided, the sensing hard pipe (3) is provided on the outer wall of the deep-sea pipeline corresponding to the position of the interface between the two pipelines, the sensing hard pipe (3) intersects with the plane where the interface between the two pipelines is located, the left section of the sensing hard pipe (3) is fixed to the outer wall of the deep-sea pipeline by a first clamp, and the right section of the sensing hard pipe (3) is fixed to the outer wall of the deep-sea pipeline by a second clamp, and the interface between the two pipelines is located between the first clamp and the second clamp; the housing (1) is fixed to the outer wall of the deep-sea pipeline; 2) After being put into operation, the processing device periodically identifies the output signals of each differential pressure sensor (2). If the output signal of the differential pressure sensor (2) exceeds a set threshold, it indicates that the deep-sea pipeline has been deformed at the corresponding position.

2. The method for monitoring deformation stress of deep-sea pipelines according to claim 1, characterized in that: The deep-sea pipeline is an oil pipeline, a gas pipeline, a steel catenary riser or an underwater cable.

3. A method for monitoring deformation stress at a deep-sea pipeline bifurcation, the hardware involved comprising a plurality of sensing devices and a processing device; a single sensing device comprising a housing (1), a differential pressure sensor (2), a sensing probe and a connecting pipe (5); The differential pressure sensor (2) is encapsulated in the housing (1); The sensing probe is composed of a sensing hard tube (3) and a pressure-guiding tube (4); the sensing hard tube (3) is a single-port tube, the port of the sensing hard tube (3) is connected to the outer port of the pressure-guiding tube (4), and the inner port of the pressure-guiding tube (4) is connected to the first input port of the differential pressure sensor (2); the sensing hard tube (3) is placed outside the housing (1); the sensing hard tube (3) and the pressure-guiding tube (4) are filled with a liquid pressure-guiding medium; a first through hole matching the pressure-guiding tube (4) is provided on the housing (1), and the middle of the pressure-guiding tube (4) is connected to the first through hole through a connector 1; The inner port of the connecting tube (5) is connected to the second input port of the differential pressure sensor (2), and the outer port of the connecting tube (5) is placed outside the housing (1); a second through hole matching the connecting tube (5) is provided on the housing (1), and the middle portion of the connecting tube (5) is connected to the second through hole via a second connector; The output parts of the plurality of differential pressure sensors (2) are connected to the processing device via electrical cables; Its characteristics are: The sensing hard pipe (3) is L-shaped; the deep-sea pipeline comprises a main pipe and a plurality of branch pipes connected to the main pipe; the method comprises: 1) A monitoring point is formed at the connection between the main pipe and the branch pipe, and a sensing device is set at each monitoring point; when a single sensing device is set, the vertical section of the sensing hard pipe (3) is fixed to the outer wall of the branch pipe through a first clamp, and the horizontal section of the sensing hard pipe (3) is fixed to the outer wall of the main pipe through a second clamp; the housing (1) is fixed to the outer wall of the deep-sea pipeline; 2) After being put into operation, the processing device periodically identifies the output signals of each differential pressure sensor (2). If the output signal of the differential pressure sensor (2) exceeds a set threshold, it indicates that the deep-sea pipeline has been deformed at the corresponding position.

4. The method for monitoring deformation stress at a deep-sea pipeline bifurcation according to claim 3, characterized in that: The deep-sea pipeline is an oil pipeline, a gas pipeline, a steel catenary riser or an underwater cable.

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