Morken Group’s inspection of 12" gas pipeline with MFL Introscope technology from an offshore platform

Natural gas production in Ecuador comes from the Amistad field, located in the Gulf of Guayaquil, Pacific Ocean, from where around 28 million cubic feet are produced per day.

This production is transported through a 12" diameter gas pipeline with a total length of 70 kilometers, which starts from an offshore gas collection and compression platform and culminates in an onshore gas dehydration plant located in the town of Bajo Alto.

As part of the mechanical integrity plan for this 12" OD gas pipeline, and in compliance with current international regulations, its inspection is contemplated every 5 years to determine the possibility of future anomalies and to know the evolution of those anomalies determined in ILI inspections executed in previous years (2012 and 2017).

Given this, the operator needs to carry out an inspection of the gas pipeline with a technology that can provide better inspection performance than those obtained in previous runs, due to the high speeds recorded in those runs and the difficulty in controlling said parameter, taking into account the strict commitments that the operator of the gas pipeline has with the thermoelectric plant that supplies one of the main cities of the country, due to the daily production volumes that this demand.

Accordingly, the operational margins of pressure and flow in the pipeline are limited, limiting the possibility of modifying the current operating parameters in order to reduce the transit speeds of the inspection tools and with them obtain inspection data from good quality that allow to validate or re-determine characteristics and dimensions of previously detected anomalies but with greater reliability and precision, especially in the internal wall of the duct, where it was possible to detect more severe anomalies in the runs of previous years.

The solution:

Morken Group proposed the use of an innovative technology in inspection tools, based on the principle of Magnetic Flux Leakage, (MFL), which is equipped with an additional inspection module, called Introscope®, capable of providing together to the high resolution MFL module, more accurate and reliable results than any other MFL High Resolution (HR) tool on the international market. The Morken Group MFL HR tool with Introscope® module provides a resolution of 2.4 mm and anomaly detection and sizing accuracies in the tube body and weld beads of +/- 0.1t (t: wall thickness of the tube) with a probability of detection of 90%. In addition, this tool incorporates a contactless, lowflow, increased passability and high temperature design capable of greatly reducing the risks inherent in failed, invalid runs and/or tool jams in the duct; as well as not damaging internal coatings, reducing friction, negotiating greater mechanical restrictions and not being affected by temperatures of up to 100°C.

Results and benefits:

Morken Group carried out successfully the inspection runs with the MFL HR tool with the Introscope® module through the 70 km length that makes up the 12” gas pipeline. Thanks to the study of previous runs with other tools and the lowflow design of the proposed tool, it was possible to effectively control the characteristic "stop and go" effect in gas pipelines, there was no damage or affectation to the tool sensors and the managed to collect 100% of the length of the pipeline. This was reflected in the high quality of the information collected and in the clarity of the characteristics and anomalies detected, exceedingly meeting the client's expectations.

With these results, the client was able to have greater certainty of the type and dimensions of the detected anomalies, with which, in turn, he was able to better discriminate the severity of these anomalies and reconsider a more assertive and reliable integrity plan.

Among the benefits achieved with these inspection runs were:

• More accurate and reliable sensing and sizing data.
• Validation and effective re-determination of anomalies with respect to previous runs.
• Rethinking of a more assertive and reliable integrity plan.
• Low risk of clogging or flow interruption.
• No disturbance of the operational conditions of the pipeline.
• Zero incidents against