Method and system for the continuous remote tracking of a pig device and detection of anomalies inside a pressurized pipeline

A system for the continuous remote monitoring of a position and advance speed of a pig device inside a pipeline suitable for transporting a pressurized fluid, wherein the pipeline includes a plurality of pipe sections joined to each other by welding seams, the system comprising:

• a plurality of measurement stations equipped with vibroacoustic sensors discretely located along the pipeline, wherein each measurement station registers the vibroacoustic signals due to the vibrations generated by contact/friction of the pig device with the welding seams and/or to other physical variations locally present in the multiple pipe sections of the pipeline;
• and
• processing circuitry operatively connected to said plurality of measurement stations and configured to:
• analyze and process the vibroacoustic signals registered by the measurement stations to reveal, identify and reference hydraulic/acoustic transients produced by the pig device as a result of contact/friction with weldings and/or with other variations of internal sections of the pipeline, and
• continuously determine a linear position and advance speed of the pig device in relation to a time lapse between the vibroacoustic signals registered by at least two measurement stations installed along the pipeline,
• wherein determination of the linear position and advance speed of the pig device is performed by a first measurement station situated on a first side of the pipeline with respect to the position of the moving pig device and a second measurement station situated on the opposite side of the pipeline with respect to the position of said moving pig device, and
• wherein the linear position and advance speed of the pig device are determined by analysis of cross-correlation on sliding time windows between the vibroacoustic signals registered by said two measurement stations installed along the pipeline, wherein a time instant of maximum correlation between the vibroacoustic signals is equal to a difference in the arrival times at said two measurement stations of the hydraulic/acoustic transients generated by the pig device and wherein the time is converted to distance by using known information on sound propagation speed in the fluid transported by the pipeline.

A method for the continuous remote monitoring of a position and advance speed of a pig device inside a pipeline suitable for transporting a pressurized fluid, wherein the pipeline includes a plurality of pipe sections joined to each other by welding seams, the method comprising the following:

• continuously acquiring and recording, by a plurality of measurement stations equipped with vibroacoustic sensors discretely located along the pipeline, of vibroacoustic signals due to the vibrations generated by contact/friction of the pig device with the welding seams of the pipeline and/or with other physical variations locally present in multiple pipe sections of the pipeline;
• analyzing and processing, by processing circuitry, the vibroacoustic signals registered by the measurement stations to reveal, identify and reference hydraulic/acoustic transients produced by the pig device as a result of contact/friction with the welding seams and/or with other variations of an internal section of the pipeline;
• continuously determining the linear position and advance speed of the pig device in relation to a time lapse between the vibroacoustic signals registered by at least two measurement stations installed along the pipeline;
• and
• acquiring data relating to the linear position of the welding seams between the pipe sections forming the pipeline and data relating to possible variations and/or anomalies on the internal section of the pipeline,
• wherein the identification of pressure peaks generated by the pig device while passing through the welding seams between the pipe sections forming the pipeline and the data relating to possible variations and/or anomalies of the internal section of the pipeline are obtained by calculating the Short Term Average over Long Term Average (STA-LTA) of the vibroacoustic signal recorded by a single measurement station and a definition of a threshold value on the resulting signal,
• wherein the determining of the linear position and advance speed of the pig device is performed by a first measurement station situated on a first side of the pipeline with respect to the position of the moving pig device and a second measurement station situated on the opposite side of the pipeline with respect to the position of said moving pig device, and
• wherein the linear position and advance speed of the pig device are determined by analysis of cross-correlation on sliding time windows between the vibroacoustic signals registered by said two measurement stations installed along the pipeline, wherein a time instant of maximum correlation between the vibroacoustic signals is equal to a difference in the arrival times at said two measurement stations of the hydraulic/acoustic transients generated by the pig device and wherein the time is converted to distance by using known information on sound propagation speed in the fluid transported by the pipeline.