The paper discusses the origins and development of a portfolio of Arctic mobile offshore drilling unit designs, comprising both jack-up type and drillship type solutions. These designs are developed to address the specific challenges of exploratory and development drilling in the Arctic, and are developed to cover the full extent of the Arctic, from the very shallow to the deep water. The paper describes both challenges and proposed solutions, as well as providing an outline of the designs.
Drilling offshore in the Arctic poses many challenges to the field operators and drilling contractors alike. More capable and bespoke solutions than available today are required to enable commercially feasible exploration and field development in the Arctic. The key factor to the drilling part is total well cost, which requires an integral solution for the drilling system to be deployed, as opposed to the traditional day rate model of the industry. The design of the drilling rig plays a central role in this, and new designs for Arctic MODUs will be required to achieve this goal.
One of the dominant factors in total well cost in the Arctic is the length of the drilling season and subsequently the ability to drill one or more wells in a season. Lowering well cost by extending the season or even enabling year round drilling is a key factor. Efficient MODU designs, allowing maximum use of the available drilling season can further enhance economics.
The paper discusses the main challenges, such as harsh environmental conditions, ice loads, shallow water challenges and logistics, and their influence on the design of Arctic MODUs. It also discusses the main principles applied in development of these designs, related to subjects such as technology qualification, safety and environmental concerns. Finally, it provides an overview and outline of the proposed design solutions.