The category B rig will be an important contribution towards increasing recovery from existing fields.Development of technology for increasing the recovery from operating fields is an area of commitment for Statoil. For the last year, the average oil recovery rate from Statoil operated fields has risen from 49 percent to 50 percent. The category B rig is designed and equipped for the industrialisation of drilling and intervention services in existing production wells and represent a new sort of service.
“This will be a very important part of the toolbox for increased recovery on the Norwegian continental shelf, making it possible to produce oil and gas that otherwise would be lost,” says Statoil executive vice president of Technology, Projects and Drilling, Margareth Øvrum. “The category B rig is the result of long-term, targeted technology development to increase subsea well recovery rates.”
In cooperation with the supplier industry, Statoil has developed a new type of rig and well control system specially adapted to carry out well intervention and drilling operations in existing subsea wells.
This type of rig fills the gap between light intervention vessels (category A) and conventional rigs (category C).The category B rig with associated integrated services is expected to reduce operating costs for well intervention by as much as 40%.
The category B design with integrated services is based on Aker Solutions own studies with a background in Statoil specifications. The rig type is designed for year-round well service in Statoil-operated activities.
The category B design provides the option for a number of different types of well interventions using wireline and coiled tubing operations.
This type of rig is also designed to carry out sidetrack drilling from production tubing (through tubing drilling – TTD) in a manner that allows simultaneous production from both the new sidetrack and existing production tubing. The well services are conducted through existing subsea Christmas trees.
This is an important piece of Statoil’s rig strategy, which is based on fit-for-purpose vessels and rigs for various operations.The key to maintaining the current production level on the Norwegian continental shelf (NCS) is increased recovery from existing fields, along with the development of new fields. Increasing drilling activity on mature fields is important in order to achieve the NCS’ full potential.
“New and improved well service methods provide a substantial contribution to increased recovery on the NCS. Statoil currently operates around 500 subsea wells, and we need efficient tools to maintain these. Collaboration between many licences has been a precondition for establishing a long-term work programme. We therefore thank our licence partners for enabling us to realise the category B service together,” says Ivar Aasheim, senior vice president of field development in Statoil.
Statoil and the licensees will enter into an eight-year contract with options for three times two years for the category B service. The estimated value of the contract is USD 1.9 billion. In addition to rig rental, the contract also includes rental of the necessary equipment and services to carry out well intervention, sidetrack drilling, ROV operations, well testing and cementing.
The rig will be in service during 2015.