Early Engagement of ECA in Offshore Deepwater Pipeline Design

Welding acceptance criteria derived through ECA is typically performed after the detailed design. The design loads, together with pipeline and girth weld material testing data, are inputs to ECA and used to evaluate the pipeline girth weld integrity for determining the criticality of potential weld flaws. With ever increasing challenging environment (deepwater, HP/HT, aggressive fluid composition etc) in the oil and gas field, the fatigue damage and fracture failure may become a serious concern, consequently limiting the productivity of the pipeline fabrication. It is therefore essential to integrate ECA into the design loop to remove the uncertainty and risk to achieve a practically workable fabrication solution. In this paper, a strategy to integrate early ECA into pipeline detailed design phase is presented. A case study in a deepwater subsea channel crossing demonstrates that an early ECA engagement effectively mitigates the significant fatigue and fracture risk and obtains workable welding acceptance criteria for fabrication.