Patent ID: 6470978
Filing Date: 2002-10-29
Classification: E21B,G01N

Abstract:
A retractable bore drilling apparatus for forming a bore hole in an underground formation, the apparatus comprising:a self-advancing drilling head having at least one high pressure fluid cutting nozzle with an at least partially forwardly directed, fluid cutting orifice configured to expel a fluid cutting jet to increase a length of the bore hole; an advancing device provided on the drilling head to provide forward movement of the drilling head from a first position in the bore hole to a second position in the bore hole; a retractable, flexible, axially unsupported conduit coupled to the drilling head and coupleable to a source of high-pressure fluid, the conduit being axially moveable through the bore hole as the drilling head moves from the first position to the second position; and a steering device having at least one jet nozzle configured to direct a jet of fluid at an angle to an axis aligned with the length of the bore hole.