The Reelwell Drilling Method is developed to improve the capability to drill wells through difficult pressure zones, to solve hole cleaning problems and to increase the ERD horizontal displacement. The method uses a concentric drill string and new downhole tools for improved downhole pressure control. The method was recently used for deepening of a well at Ullrigg in Stavanger, Norway. Here the 8 ½" hole section was drilled with a downhole motor and MWD to verify the capability for directional drilling and for downhole pressure control.
The results from the drilling operation show that the Reelwell Drilling Method has successfully verified all the pilot well drilling objectives:
Excellent interaction with conventional mud pulse MWD.
Full directional drilling control.
Precise downhole pressure control, including the capability for downhole pressure isolation.
The new equipment and procedures have been reviewed and certified by DNV, and the plain version of the Reelwell Drilling Method is now ready for commercial applications. The liner drilling version is planned to be qualified within short time.
The Reelwell Drilling Method has the recent years been developed in a Joint Industry Project supported by StatoilHydro, Shell and The Research Council of Norway. During the development period 2005–2008 the Reelwell Drilling Method has been successfully tested and verified in several full scale drilling operations at Ullrigg at IRIS in Stavanger, see ref /1/.
The new drilling method can be used to avoid drilling problems and to improve drilling performance for various applications. However, unique features are obtained for the following applications:
Managed Pressure Drilling - including unique downhole pressure isolation.
Liner Drilling - optionally, a liner may be installed and potentially expanded enabling immediate wellbore isolation.
Deep Water Drilling - enabling the use of low pressure riser and advanced well annulus gradients.
Extended Reach Drilling - unique hole cleaning combined with hydraulic downhole thrust force.
The Reelwell Drilling Method was used to perform an onshore drilling operation at Ullrigg earlier this year. In this operation the 8 ½" section of a test well was drilled in order to perform an integration and qualification of an industry standard version of the plain drilling system, including MWD and directional drilling with downhole motor. Special attention was also given to the downhole pressure control. The drilling operation was performed as a qualification program for field applications. This program also included involvement from DNV, for certification of tools and procedures.