Abstract: A horizontal directional drilling system is used to drive operation of a guidable reamer assembly connected to a drill string. The guidable reamer assembly preferably has a cutting member with a central longitudinal axis and a support member also having a central longitudinal axis. The longitudinal axes of the cutting member and the support member are collinear when the reamer assembly is in the non-steering position and laterally displaced when in the steering position. The assembly and method of this invention provide for increased control of reaming operations and product pipe placement.

Abstract: A system for monitoring deflection of a downhole tool assembly. The system comprises a beam source directing a beam at a receptor positioned proximate the downhole tool assembly. The receptor detects the position of incidence of the beam at the receptor. A processor receives signals from the receptor and determines angular deflection of the downhole tool assembly based on incidence of the beam at the receptor. Information from other orientation sensors is also used to determine magnitude and direction of deflection. Deflection information is used by an operator or a control system to maintain or correct the course of the downhole tool assembly.

Abstract: A tracking receiver system is used to track the progress of a downhole tool along a subsurface path having a desired grade. The tracking receiver system is adapted to detect a reference line originating from a reference line receiver and to determine the position of the downhole tool along a desired subsurface path relative to the reference line. In an alternative embodiment the tracking receiver system may comprise a global positioning satellite system to provide information used to determine the position of the downhole tool relative to the desired subsurface path.

Abstract: A coupling assembly to interconnect an inner member and an outer member of a dual member drill string in torque transmitting engagement is disclosed. The coupling assembly is adapted to transmit torque input from both members to a downhole tool. In one embodiment, the coupling assembly comprises a connector sub that fixedly and non-fixedly couples both members. In another embodiment, the coupling assembly comprises a clutch mechanism to interconnect both members when the rotational speed of the outer member exceeds the rotational speed of the inner member. In another embodiment, the coupling assembly comprises a mechanism to couple both members by axial downhole movement of the inner member relative to the outer member. In another embodiment, the coupling assembly comprises a planetary gear system that interconnects both members to provide high torque to the downhole tool at relatively low output speed of the dual member drill string.