Oil and gas pipeline interference signal suppression method based on alternating excitation

Abstract

The invention discloses an oil and gas pipeline interference signal suppression method based on alternating excitation. The method comprises the following steps of collecting condition data such as the size, the material, the position and the pipeline trend of a target pipeline; preparing experimental pipelines of the same material and model, and building an experimental system; adjusting a transmitter to add different frequencies to the pipeline, and collecting pipeline signals under different frequencies; processing the collected data, and finding out the frequency when the pipeline signal is maximally enhanced; when the frequency is applied to field detection, the influence of an interference signal on a pipeline signal can be best inhibited. According to the method, the signal size of the pipeline can be enhanced most effectively, the influence of interference signals on the pipeline signal is inhibited to the greatest extent, and the method has important guiding significance for detecting and analyzing the real state of the pipeline.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas pipeline safety, and in particular to an oil and gas pipeline interference signal suppression method based on alternating excitation. Technical Background

[0002] Oil and gas pipelines are in a complex environment for a long time. The oil and gas medium transported by the pipeline, moisture in the soil, and microorganisms will corrode the pipeline; excessive operating pressure of the pipeline, third-party damage, and other reasons will also cause pipeline stress concentration. Therefore, it is necessary to detect the pipeline to ensure the safe operation of the pipeline. Oil and gas pipeline detection usually uses a variety of technologies, among which non-contact magnetic detection technology has a good application prospect. In non-contact magnetic detection, ferromagnetic interference objects around the pipeline and the magnetic field generated by nearby electrical equipment will generate interference signals. These interference signals may be confused with the magnetic signals caused by defects such as pipeline stress concentration, corrosion, and cracks. The interference signals will cover up the real pipeline defect signals, resulting in the inability to effectively identify the real situation of the pipeline. At present, the research on reducing the impact of interference signals is mainly about signal shielding instruments, and there has been no research on interference signal suppression methods based on alternating excitation for oil and gas pipeline interference factors. In order to detect and analyze the real state of the pipeline and ensure the safe operation of the pipeline, it is necessary to suppress the interference signals that affect the pipeline detection signals, so as to judge the actual condition of the pipeline.

[0003] At present, there is no method for suppressing oil and gas pipeline interference signals at home and abroad, and there is no research on the method for suppressing oil and gas pipeline interference signals based on alternating excitation. Summary of the invention

[0004] In view of the above problems, the present invention aims to provide a method for suppressing interference signals of oil and gas pipelines based on alternating excitation. The method overcomes the existing technical defects, can not only suppress the interference of interference signals on pipeline signals, but also restore the real state signal of the pipeline.

[0005] The technical solution provided by the present invention to solve the above technical problems is a method for suppressing interference signals of oil and gas pipelines based on alternating excitation, comprising the following steps:

[0006] S1. Survey the on-site environment to determine the size, material, location and direction of the pipeline to be tested.

[0007] S2. Prepare experimental pipelines of the same material and model as the on-site pipelines, and test the signal conditions of the pipelines at different frequencies.

[0008] S3. Use the direct connection method to directly connect the two sides of the pipeline through wires so that the transmitter and the pipeline form a loop to detect the impact of the applied frequency on the pipeline signal.

[0009] S4. Adjust the transmitter, use the transmitter to apply different frequencies to the pipeline, and use the magnetic detection equipment to detect the magnetic signal data of the pipeline at different frequencies.

[0010] S5. Plot the collected magnetic signals of the pipeline under interference at different frequencies on a graph, compare and analyze, and find out which frequency has a significant enhancement effect on the pipeline detection signal. Since the wire is directly connected to the pipeline, it only enhances the pipeline signal without increasing the signal of the interference object, which in disguise suppresses the influence of the interference signal on the pipeline signal.

[0011] S6. Use this frequency to detect the on-site pipeline. Use the direct connection method to apply the frequency to the on-site pipeline. The application method is as follows:

[0012] (1) Use a special clamp or welding wire (if welding is allowed on the pipeline) to connect the output or input of the transmitter directly to the pipeline. If a clamp is used, make sure that the clamp can tightly clamp the pipeline and has a good connection with the output cable of the transmitter.

[0013] (2) Connect the other end of the transmitter to the pipeline’s negative pole to form a loop between the pipeline and the transmitter.

[0014] S7. Adjust the transmitter to obtain the frequency with the strongest enhancement effect on the pipeline signal obtained during the experiment on the on-site pipeline, so as to achieve the best suppression effect on the interference signal.

[0015] S8. Install the magnetic detection equipment. The operator holds the detection device and steadily detects along the pipeline to obtain the pipeline detection signal. This signal is closest to the signal when the pipeline is not disturbed. It can be approximately regarded as the real signal of the pipeline and can reflect the real status of the pipeline.

[0016] S9. Analyze the detection data to obtain the real status of the pipeline.

[0017] The oil and gas pipeline interference signal suppression method based on alternating excitation of the present invention can be applied to most oil and gas transportation pipelines. Different experimental simulations can be performed on pipelines of different materials to find out the frequency that best suppresses interference signals. This can then be applied to on-site operating pipelines, and the impact of interference signals on pipeline signals can be better ignored, restoring the true state of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0019] Figure 1 The magnitude of the magnetic gradient component of the experimental pipeline at different frequencies

[0020] Figure 2 Experimental diagram when adding incentives to the experimental pipeline DETAILED DESCRIPTION

[0021] The present invention is further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art to which this application belongs.

[0022] The present invention provides a method for suppressing interference signals in oil and gas pipelines based on alternating excitation, comprising the following steps:

[0023] S10. Survey the on-site environment to determine the size, material, location and direction of the pipeline to be tested.

[0024] S20. For on-site investigation of pipeline conditions, prepare experimental pipelines of the same steel quality and model, and test the pipelines to detect signal conditions at different frequencies.

[0025] S30. Use the direct connection method to directly connect the two sides of the pipeline through wires so that the transmitter and the pipeline form a loop to detect the impact of the applied frequency on the pipeline signal.

[0026] S40, adjusting the transmitter, using the transmitter to apply different frequencies to the pipeline, and using a magnetic detection device to detect magnetic signal data of the pipeline at different frequencies.

[0027] S50. The collected magnetic signals of the pipeline with interference at different frequencies are plotted on a graph. Comparative analysis shows that 8.31kHz has the greatest enhancement effect on the pipeline signal and the greatest suppression effect on the interference signal.

[0028] S60, using the frequency to detect the on-site pipeline, applying the frequency to the on-site pipeline using a direct connection method, the application method is as follows:

[0029] (1) Use a special clamp or welding wire (if welding is allowed on the pipeline) to connect the output or input of the transmitter directly to the pipeline. If a clamp is used, make sure that the clamp can tightly clamp the pipeline and has a good connection with the output cable of the transmitter.

[0030] (2) Connect the other end of the transmitter to the pipeline’s negative pole to form a loop between the pipeline and the transmitter.

[0031] S70. Adjust the transmitter to apply a frequency of 8.31kHz to the on-site pipeline.

[0032] S80. Install the magnetic detection equipment. The operator holds the detection device and steadily detects along the pipeline to obtain the pipeline detection signal. This signal is closest to the signal when the pipeline is not disturbed and can be approximately regarded as the real signal of the pipeline, reflecting the real state of the pipeline.

[0033] S90. By analyzing the detection data, the actual status of the pipeline can be determined.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The oil and gas pipeline interference signal suppression method based on alternating excitation of the present invention can provide a way of suppressing interference signals for most oil and gas transportation pipelines. By conducting experiments and quantitative analysis on different pipelines, the frequency size when the pipeline signal is best enhanced can be obtained, thereby achieving the best suppression effect on the interference signal. During specific implementation, the material model of the pipeline can be adjusted according to the actual situation on site, and the experiment can be redesigned to ensure that the best frequency size that can enhance the pipeline signal is obtained.

[0036] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for suppressing interference signals in oil and gas pipelines based on alternating excitation, characterized in that: The following steps are involved: S1. Survey the on-site environment and determine the size, material, location and direction of the pipeline to be tested; S2. Prepare experimental pipelines of the same material and model as the on-site pipelines, and test the signal conditions of the pipelines at different frequencies; S3. Plot the collected magnetic signals of the pipeline with interference at different frequencies on a graph, compare and analyze, and find the frequency with the best enhancement effect; S4. Use the frequency to detect the on-site pipeline, and apply the frequency to the on-site pipeline using the direct connection method; S5. Adjust the transmitter to obtain the frequency with the strongest enhancement effect on the pipeline signal obtained during the experiment on the on-site pipeline, so as to achieve the best suppression effect on the interference signal; S6. Install the magnetic detection equipment. The operator holds the detection device and steadily detects along the pipeline to obtain the pipeline detection signal. This signal is closest to the signal when the pipeline is not disturbed. It can be regarded as the real signal of the pipeline and can reflect the real state of the pipeline. S7. Analyze the detection data to obtain the real status of the pipeline.

2. According to claim 1, different frequencies are applied to the test pipeline, characterized in that: In step S3, using a transmitter, adding different frequencies to the experimental pipeline includes the following steps: S21. Use the direct connection method to directly connect the two sides of the pipeline through wires, so that the transmitter and the pipeline form a loop; S22. Adjust the transmitter, change the frequency, and apply different frequencies to the pipeline.

3. The best frequency obtained by applying the experiment to the field pipeline according to claim 1, characterized in that: In step S4, simulating the pigging conditions under different pigging parameters includes the following steps: S31. Use a special clamp or welding wire (if welding is allowed on the pipeline) to connect the output or input of the transmitter directly to the pipeline. If a clamp is used, make sure that the clamp can tightly clamp the pipeline and is well connected to the output cable of the transmitter. S32. Connect the other end of the transmitter to the pipeline's negative pole to form a loop between the pipeline and the transmitter.

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