Patent ID: 8011453

Claim:
A drilling system, comprising: a drilling machine; a drill string connected at one end to the drilling machine so as to be driveable in an axial direction; and a guide connected to the drilling machine such that when the drill string is driven axially by the drilling machine, the drill string interacts with the guide so as to be directed in a predetermined radial direction; wherein the guide is rotatable by the drilling string and fixed relative to the drilling machine in the axial direction; wherein the drill string is permanently engaged so as to be slideable in the guide; wherein the drilling machine includes a drilling tractor for moving the drill string in the axial direction, and anchors operable to engage a main borehole and provide a reaction to axial and rotation forces; and wherein the guide comprises anchor arms mounted thereon and movable between a first position close to the guide and a second position in which they engage the main borehole wall to anchor the guide in place whereby the drilling machine can push the drill string forward while the guide stays anchored at a fixed position; the anchor arms of the guide being separate from the anchors of the drilling machine so as to allow the guide to be anchored after the drilling string is directed in the predetermined radial direction while the drilling machine is anchored in the main borehole by the anchors.