Development and testing of cleaning and in line inspection tools for the integrated gas flow system of the Pre-salt in the Santos Basin

Abstract

The internal inspection of the Rota 1, 2, and 3 gas pipelines is considered a technological milestone for deepwater exploration. The challenge of developing cleaning and inspection PIGs involved pipelines with a large variation in diameter, ranging from 18 to 24 inches, long distances of up to 450 kilometers, high operating pressures of up to 250 kgf/cm², water depths of up to 2400 meters, and passage through equipment with complex geometries. The risk of this operation, in terms of the possibility of PIGs getting stuck, was considered medium/high. To reduce this risk, a phase of tool homologation was planned. After a thorough verification of the documentation of the subsea system components, the minimum tests necessary to assess the operational performance of the tools in scenarios of high pressure exposure, displacement at low flow rates, detection of anomalies at high speeds, and durability/wear over long distances were defined. At the end of the homologation phase, full-scale tests were carried out in a circuit containing 51 components that represented the restrictive geometries of the subsea system. Another measure taken was the use of radioactive isotope transmitters, increasing the autonomy in case the PIG needed to be located. So far, 03 out of 04 pipelines have been inspected with these tools.