Top-of-Line Corrosion Mechanism for Sour Wet Gas Pipelines

Abstract

Abstract Large diameter subsea pipelines operating mainly in stratified flow are being used across the world for wet gas transportation over significant distances from offshore fields to onshore facilities. Understanding corrosion mechanism occurring at the top of the line under dewing conditions is a key component of operations corrosion management strategy to ensure long-term pipeline integrity. The challenge in predicting corrosion in sour systems is due to the varied nature of iron sulfide scales formed over the expected subsea pipeline temperature ranges and condensation rates that result in different corrosion mechanisms. Current industry practice is to use sweet corrosion prediction methodologies to establish the risk of top of line corrosion in sour systems. This paper will demonstrate through field validated laboratory results that this approach may be inadequate and propose operational practices to manage the risk of top of line corrosion in large diameter subsea wet gas pipelines.