The recently installed TurkStream offshore pipelines are routed through the Black Sea, from Russia to Turkey. The twin 32” export gas pipelines are 940 km long and laid along the seabed to a maximum depth of 2,200m. In a world-first for this type of pipeline, TurkStream and DNV GL deemed the engineering and construction standards to be sufficiently high to waive the traditional pre-commissioning hydrotest. Subsequently, with Baker Hughes, a new type of “dry pre-commissioning” was developed. Pipeline cleaning, gauging and caliper inspection remained project requirements. The fast-tracked Baker Hughes operations centered on using a membrane nitrogen generation spread to propel a multi-function 6 pig train and mono-ethylene glycol (MEG) slugs, safely and efficiently from Russia to Turkey. This paper details several of the technical challenges which were overcome in the development of a successful and innovative “dry pre-commissioning” methodology that demonstrates the viability of the no-hydrotest approach for major export pipelines.
Innovations in Pipeline Pre-commissioning
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