Joint projects probing pipo-in-pipe impairment, flow assurance concerns

摘要

Production from deep offshore oil and gas fields often requires good thermal insulation to limit the risk of hydrate formation or wax deposition. Pipe-in-Pipe structures (PiP) are one of the most effective solutions for obtaining low thermal conductivity values (U-value). Their effectiveness as an insulation system can be impaired, however, by the presence of hydrogen in the annulus. The goal of the Hypip joint industry project (JIP), launched recently by Institut Francais du Petrole, is to analyze how the fluid composition flowing inside the PiP may damage the thermal insulation through the generation of hydrogen in the annulus, and also to evaluate potential remedies. Numerous laboratory studies have been devoted to hydrogen charging into steel when exposed to sour media. However, the hydrogen permeation is strongly dependent on the hydrogen charging condition (sour corrosion) and extraction power (respectively low and high for thick and thin steel membranes). For instance, for thin steel membranes (approximately 2 mm), permeation rates as high as several kPa/dayhave been detected for an annular space arrangement of one inch.