Key challenges and new solutions for the decommissioning of flexible pipelinesaffected by SCC-CO2 phenomenon

a case study from the mero field

Abstract

The SCC-CO₂ phenomenon represents a critical challenge for flexible pipeline decommissioning. This condition causes a degradation mechanism that significantly reduces equipment service life. This work analyzes the key challenges in decommissioning flexible pipelines in Mero Field affected by this failure mechanism, using the SPA-1 decommissioning project as a case study. These pipelines operated in Mero Field through the Pioneiro de Libra FPSO, Santos Basin, between 2017 and 2022. The retrieval of these subsea lines faced several operational challenges during execution. This study is justified by the need to find a safe method for retrieval, the high cost of these operations due to increased activity duration, and its scope for similar projects in Santos Basin. The methodology was based on analysis of different operational scenarios, development of integrity testing procedures, reduction of workforce exposure to operational risk, and consolidation of the stern retrieval technique using PLSV vessels for this group of pipelines. These changes caused a significant increase in activity duration. The pilot operation was executed with four vessels operating simultaneously for retrieval. The implemented solutions eliminated safety risks, bringing effectiveness to operations and ensuring execution of these activities without new interruptions.