Increased recovery through light well intervention

Statoil awarded Island Offshore a framework agreement earlier this year for light well intervention (LWI) services from their Island Constructor vessel.

The new vessel is set for operation in December, and is Statoil’s third light well intervention vessel in operation on the Norwegian continental shelf (NCS).

Light well intervention vessels – known as cat A – are an important tool to increase recovery from the fields on which Statoil operates.

Compared with conventional drilling units, these LWI vessels reduce the cost of well interventions substantially. Reduced well intervention costs also helps increase the number of interventions.

“Performing conventional jobs of this kind for subsea developments in areas with low volumes of oil in place has been expensive,” says Statoil drilling and well technology operations manager Øyvin Jensen.

“To address this, Statoil has put LWI vessels into service on a large scale. This is of high value to us, both in terms of efficiency and cost reduction.”

Light well intervention vessels are an important tool in Statoil’s toolbox to increase field recovery. A growing number of discoveries are developed via subsea installations. At the same time, production from mature fields is declining.

Wells need workover in order to maintain their output. These have historically been expensive operations on subsea developments.

Utilising light well intervention vessels contributes to a more cost-effective maintenance of subsea wells, improves drilling efficiency, and provides the potential to offset rig capacity.

Statoil has pursued riserless wirelining in subsea wells since 2000, and the technology has steadily improved.

Statoil issued a new tender for light well intervention vessels this autumn. The invitation to tender was issued in October, and the bids are due in December this year.  

“We already have three light well intervention vessels in our portfolio. The new tender process will cover our needs for light intervention services when the existing vessels come off contract,” says Statoil vice president for drilling and well procurement Terje Rognan.

“We are tendering for a minimum of two such vessels and are open for long-term commitments. With 487 subsea wells on the NCS, it is evident that this is an important market segment for Statoil going forward and subsequently of high interest for the supplier industry and shipowners.”