US Patent 9074455 Systems and methods for continuous and near continuous drilling

The present disclosure provides drilling and tripping equipment packages and control schemes and methods using two or more lifting systems that operate simultaneously and continuously in a synchronized manner such that the feeding of tubular 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 packages and control schemes are also able to rotate the tubular 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 tubular with sufficient pressure and flow to facilitate both drilling and back-reaming operations, with minimal interruption to circulation.