Subsea well intervention activities are expected to flourish over the next five years, says maritime industry consultancy Douglas-Westwood (DW).
Despite the recent plunge in oil prices, DW expects the global subsea well stock to increase over the period by 41 per cent – driven by an increase in ultra-deepwater (>1,000 metres) activities.
Maturing subsea wells, of which 77 per cent are over five years old, will increase demand for workover units in Latin America, North America and Western Europe. However, the greatest levels of growth is expected in Africa, where demand could rise at approximately 20 per cent CAGR.
Whilst either rigs or vessels can carry out well intervention operations, vessels usually command lower day rates and are more mobile, thus reducing both costs downtime, said DW.
Additionally, most well interventions are classified as "light" or "medium", meaning a rig is not required and the operations can be carried out by riser-less or riser vessels.
"Nonetheless, based on operators' revealed preferences, there does not appear to be a straightforward indication of the best unit type," said DW. "For example, Statoil is a frontrunner when it comes to utilising riser-less intervention, whereas, Petrobras' subsea well intervention programs are currently solely carried out by drilling rigs.
"However, efficiency assessments should also consider mobilisation costs, operational costs, crew specialisation (which reduces risk of incidents) and time efficiency.
"Therefore, the key question for operators is: will these costs offset potentially lower day rates in oversupplied markets?"
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