Patent ID: 9637995
Date: 2017-05-02
CPC Classifications: E21B

Claim:
1. A drilling apparatus for allowing continuous drilling with drill string rotation and vertical translation with circulation of mud while adding or removing tubulars from a drill string during the drilling of a well, the apparatus comprising: an upper snubber and snubber drive adapted to apply sufficient torque to a rotating tubular to make or break tool joint connections, a pressure chamber located beneath the upper snubber and comprising seals, a blind ram and a mud inlet and outlet, and a drill string drive beneath the pressure chamber, adapted to apply torque and support to a rotating drill string during said connections and during said continuous drilling and when said tool joint is disconnected or connected, a differential drive train interconnecting said snubber drive and the drill string drive, said differential drive train decouples the drill string drive from the snubber drive, an extension sub adapted to automatically lengthen to allow vertical translation of a drill bit at the end of a drill string such that weight is kept on the drill bit and drilling continues uninterrupted during drill string connections, said extension sub comprising splined telescopic shafts and at least one spring or hydraulics to set tension or compression forces at which the extension sub begins to extend as the drill string continues to drill during drill string connections.