The Operational and Economical Impact of CT Spoolable Connectors During the Last 5 Years in the Norwegian and Danish Sector of the North Sea: Case Histories

Sach, Manfred (BJ Services Company) | Maribu, Kenneth (ConocoPhillips Co) | Haga, Jarle (Talisman Energy Norge AS) | Nesvik, Kjell Tore (Statoil ASA) | Boye-Moller, Christian (DONG Energy E&P)


Coiled Tubing (CT) equipment in the Norwegian sector of the North Sea has traditionally been heavy, due to CT reels using larger sizes of CT - a trend also observed in other areas. Due to the requirement of performing well interventions in longer wells and larger completion sizes, CT drums weighing 40-60 t have been utilised. Not many platform cranes are capable of lifting such heavy CT drums and during bad weather periods operations are often delayed, even when using significantly lighter CT drums. Using spoolable CT connectors allow for a long and heavy CT string to be lifted on board of a platform on two or more separate drums and joining them together again once onboard. More than 50% weight reduction has been achieved making operational schedules more predictable. In the geographical areas considered, spoolable CT connectors have outperformed traditional methods like boat spooling and butt-welding from a safety, operational and economical point of view.

Due to the reduction in weight, larger CT sizes have become available on older platforms as well. New CT applications that were previously considered unfeasible, like selective, high-rate acid fracing through CT, have been performed, extending the capabilities of CT interventions beyond previous logistical and technical limits. Being able to select the correct size of CT, with less dependency on offshore crane limits and weather has a fundamental impact on the usage of CT in the offshore industry.

Rather than discussing the spoolable CT connector itself, the primary intention of the paper is to re-view case histories that were performed during the last 5 years. Operational challenges that have been mastered, successes, failures and further developments are presented. A new CT reel configuration to simplify spoolable CT connector installation will be presented. The new applications made possible by this technology and their economic impact on the Norwegian CT market since year 2003 will be reviewed.