Patent ID: 6702040
Filing Date: 2004-03-09
Classification: E21B

Abstract:
A telescopic drilling method, comprising the steps of:(a) drilling an outer bore through a surface, the outer bore defined by an outer bore wall and an outer bore base and having an outer bore diameter and a first outer bore depth; (b) inserting a hollow outer conduit into the outer bore, the outer conduit having a drill end with a ring drill bit rotatably attached thereto; (c) at least partially inserting a first hollow inner conduit through the outer conduit; (d) preventing the first inner conduit from moving longitudinally with respect to the outer conduit; (e) engaging a rotatable inner drill bit with the ring drill bit, thereby creating a unitary drill bit head; (f) further drilling the outer bore using the unitary drill bit head to a successive outer bore depth; (g) disengaging the inner drill bit from the ring drill bit, such that the outer conduit is capable of moving freely within the outer bore; (h) attaching a second end of a successive hollow inner conduit to a first end of an immediately preceding inner conduit, thereby creating an extended inner conduit; (i) unclamping the preceding inner conduit; and (j) repeating steps (c)-(g) utilizing the extended inner conduit.