A long history of wet gas pipelines in Victoria

Abstract

Australia's relative isolation and the harsh environment in Bass Strait have led to many innovations in offshore oil and gas developments. The initial developers were moving into frontier territory when Bass Strait was developed, with the harsh sea state and the water depths presenting major challenges. The original development of Bass Strait in the 1960s was tied to a wet gas pipeline philosophy, which was a novel step-out from normal industry practice. For example, the North Sea developments, which started shortly after Bass Strait, adopted dry gas export pipelines and required substantially larger platforms to process the gas for export. The cold waters of Bass Strait require an active hydrate management strategy and the success of hydrate inhibitors has been a key element in using wet gas pipelines. The initial development relied on methanol for hydrate inhibition, but this changed to a glycol-based hydrate inhibitor within 10 years of production start-up, due to challenges in the onshore production facilities. The use of mono-ethylene glycol for management of wet gas pipelines was demonstrated in Bass Strait. The success of the initial developments has given operators the confidence to pursue marginal field developments that rely on wet gas transport to the beach. The Minerva, Casino, Thylacine and Longtom gas field developments in Bass Strait have all adopted the same strategy, in part because of the confidence provided from operating the initial developments for many years.