Coiled-tubing technology is commonly used in well servicing to deliver effective solutions in the oil and gas industry. However, coiled tubing is extremely versatile and may be used to deliver cost-effective solutions in many applications outside of well intervention. This paper details the planning, design, and execution of a 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 obtained core samples to verify rock quality before tunnel drilling.
The Norwegian government is enhancing the connectivity of its road network by building a road connecting Stavanger to Bergen. This route includes a 25-km tunnel along the future Rogfast route on the Norwegian coast. To make tunneling operations more efficient, verification of rock quality ahead of tunnel construction eliminates the requirement of drilling pilot holes ahead of the main tunneling machinery. Eliminating the pilot-hole requirement optimizes the tunnel route and significantly reduces tunnel construction time. Therefore, coiled tubing was deployed from a light-well-intervention vessel and drilling and coring operations were performed along the route, enabling rock samples to be collected before tunnel construction. This required surface and subsea coiled-tubing injectors that could be controlled simultaneously and independently. The system is deployed from a light-well-intervention vessel without the use of a riser....
Core Drilling Using Coiled Tubing From a Riserless Light-Well-Intervention Vessel
01 June 2016