This paper details the planning, design and execution of a successful project involving the core drilling of three wellbores using coiled tubing directional drilling along the future "RogFast" tunnel route on the Norwegian coast. The project obteined core samples to verify rock quality prior to the commencement of tunnel drilling.

The project required several new technologies and techniques to enable the collection of the core samples.

The combined use of surface and subsea coiled tubing injectors operated from a vessel in combination had not been attempted and therefore was an area of concern, which was addressed during the operation design phase.

Project planning included the theoretical analysis of the fatigue effects on the coiled tubing between the surface and the subsea injectors, requiring the development of a secondary injector control panel and several modifications to the vessel systems.

The project resulted in a successful drilling and coring operation without incident or environmental spill following many months of planning, job design and use of a highly skilled team during the operation.

You can access this article if you purchase or spend a download.