http://www.maths-in-industry.org/miis/246/ Underreamer mechanics Jones, Marvin Barton, David Hall, Cameron Coskun, Erhan Lacey, Andrew Lorenz, Maike Maringer, Johannes Please, Colin Richardson, Giles Energy and utilities In the oil and gas industry, an underreamer is a tool used to extend and enlarge the diameter of a previously-drilled bore. The problem proposed to the Study Group is to obtain appropriate mathematical models of underreamer dynamics, in forms that will lead to feasible computation. The modes of dynamics of interest are torsional, lateral and axial. This report describes some initial models, two of which are developed in more detail: one for the propagation of torsional waves along the drill string and their reflection from contact points with the well bore; and one for the dynamic coupling between the underreamer and the drill bit during drilling. 2009 Study Group Report NonPeerReviewed application/pdf http://www.maths-in-industry.org/miis/246/1/SmartReamer-Underreamer.pdf Jones, Marvin and Barton, David and Hall, Cameron and Coskun, Erhan and Lacey, Andrew and Lorenz, Maike and Maringer, Johannes and Please, Colin and Richardson, Giles (2009) Underreamer mechanics. [Study Group Report] http://www.maths-in-industry.org/miis/246/http://www.maths-in-industry.org/miis/246/1/