Sandwich Pipe: Technical Viability in Subsea Gas Pipelines

The exploration and advancement of subsea technology, especially in gas pipelines, has always necessitated innovative solutions. This study evaluates the potential of sandwich pipes for such applications, advocating for their technical and economical benefits over traditional single-walled pipes. To substantiate these claims, full-scale prototypes of the sandwich pipes were manufactured. These were tested at the reputable Subsea Technology Laboratory (COPPE/UFRJ). The assessment criteria were based on collapse and propagation buckling, and the installation feasibility was considered using the Reel-Lay method. This rigorous testing regimen facilitated a detailed numerical-experimental analysis. The primary goal was to fine-tune and calibrate a tool capable of accurately simulating the structural behavior of the sandwich pipe. This tool harnesses the capabilities of the finite element method within the ABAQUS software. Further, following a validation process, the study ventured into an intricate lateral buckling analysis. Here, the focus was the displacement-controlled local buckling limit state (DCC), emphasizing the pipe-soil interaction in the pre-salt region’s clay soil of the Brazilian coast. The findings were promising. The observed longitudinal strains fully complied with standards set by DNV-ST-F101 (Submarine pipeline systems) and DNV-RP-F110 (Global buckling of submarine pipelines). They remained below the critical 0.4% threshold. A comparative analysis was presented as the study culminated, emphasizing the sandwich pipe’s structural resistance to collapse and cost benefits over its single-walled counterpart.