Abstract: A fluid cutting head of the type having a plurality of nozzles in a rotatable nozzle assembly for cutting a bore hole in rock. The cutting head has nozzles arranged to be supplied with high pressure drilling fluid, forming jets positioned to cut adjacent rock. The nozzles include one or more generally axially facing pilot nozzles, and one or more generally radially facing reaming nozzles. At least the pilot nozzles include a non-tapering outlet section such that the jet issuing therefrom is of substantially constant cross-section in a zone immediately adjacent the outlet section. The pilot nozzles are located in a leading part of the rotatable nozzle assembly, and have a minimized diameter. The reaming nozzles are located in the following part of the rotatable nozzle assembly. The following part of the rotatable nozzle assembly is formed in a step-wise fashion to keep the reaming nozzles close to the rock face.

Abstract: The invention provides a coiled tube drilling rig (1) for drilling boreholes. The rig includes a drum (2) mounted about a longitudinal axis (B-B) and adapted for receiving a length of semi-rigid tubing (4) wound onto the drum. An injector unit (10) is provided for deploying the tubing (4) along a tubing deployment axis (A-A) and into a borehole, the deployment axis (A-A) being generally orthogonal to and intersecting the drum rotation axis (B-B). An indexing guide (11), confines the tubing in a indexing zone, between a moveable tangential separation point (14) on the drum and the deployment axis (A-A), to a deployment plane (X). The plane being defined by the location of the deployment axis and the separation pint (14). The drum is configured to pivot with respect to the deployment plane around an axis (C-C) substantially collinear with said deployment axis (A-A).