US Patent 8955602 System and methods for continuous and near continuous drilling

The present disclosure provides a drilling and tripping equipment package and control scheme and methods using two or more systems that operate simultaneously and continuously in a synchronized manner such that the feeding of tubulars into or out of a well bore is achieved with continuous or near continuous movement, without the need for periodic interruptions. The drilling and tripping equipment package and control scheme is also able to rotate the tubulars in the well bore with continuous speed and torque sufficient for both drilling and back-reaming operations. The drilling and tripping equipment package and control scheme is additionally able to circulate drilling fluid into the internal bore of the tubulars with sufficient pressure and flow to facilitate both drilling and back-reaming operations, with minimal interruption to circulation.