Pigging and SPL development
Discovered deepwater fields may have oil recovery not large enough for independent hub development. The solution to tie back this marginal field to an existing host through a Single Production Line (SPL) is an economic development.SPL looped with one service line (smaller diameter) or SPL equipped with an electrical heating system have been identified as frontrunners but create some operability issues. One concern is the line inspection with intelligent pigging.
Such operations are complex with specific issues related to deepwater conditions, such as hydrate formation and pig velocity control. Subsea pig launcher, injection hoses and one multi purpose vessel will have to be mobilised for days. Production will also be stopped during days. Even with the best preparation, the risk to abort such inspection operations will always exist.
For all these reasons, the benefit of pigging must be precisely evaluated during the early stage of SPL development. All operational and logistical issues will be identified, and the subsea system design adapted accordingly. Pending risks associated to subsea pigging, the solution to provide a looped SPL (service line with diameter continuity) will also have to be considered as a serious alternative to allow round trip pigging from the existing host. More details are available in paper 19941 presented by ADC during OTC 2009.
Enter X at www.engineerlive.com/iog
DORIS Engineering is based in Paris, France. www.doris-engineering.com
