This paper addresses the lateral buckling reanalysis performed after the as-built survey of rigid flowlines recently installed in the Mero 2 Field, located in the deep waters of the Santos Basin, offshore Brazil.

The Mero 2 project comprises rigid mechanically lined pipe (MLP) systems. The field operates under high internal pressure and high operating temperature (HPHT) conditions with different fluid types (oil and water alternating gas, i.e., WAG). The flowlines undergo permanent and transient flow regimes with several predicted shutdown/start-up cycles during their design life. Both ends are fully constrained with exposed pipeline conditions. The severe operational scenarios occurring in the subsea flowlines induce large compressive axial forces, necessitating mitigation by controlling the lateral buckling behavior, which is ensured through the Residual Curvature Method (RCM).

An as-built survey, including a multibeam system, was performed on all oil production and water alternating gas flowlines. The as-built survey campaign of the project phase was conducted just after the pressure test (i.e., flooded pipeline without pressure).

As-built data were post-processed and used for a complete update of the full-length finite element models developed during the detailed engineering phase. A comparison is conducted between the lateral buckling response obtained respectively from as-built re-assessment and detailed design phase. This includes analyzing discrepancies in the buckling behavior, evaluating the accuracy of the initial design assumptions, and assessing the impact of any deviations on the overall pipeline integrity and performance. The comparison aims to validate the outcomes of prior engineering analyses and assess the robustness of the lateral buckling mitigation measures implemented.

This paper outlines the critical aspects of the methodology and highlights the most challenging and time-intensive tasks encountered during the assessment, including post-processing, smoothing survey data, updating pipe-soil interaction data, and verifying the reliability of the buckling initiation strategy.