Patent ID: 7296639
Filing Date: 2007-11-20
Classification: E21B

Abstract:
1. A well-drilling bit assembly suitable for through-bit operation comprising a well-drilling bit, which includes a bit body having upper and lower ends having a passageway there through, the bit body being attachable at its upper end to a tubular drill string and the passageway extending between an opening at the upper end and the exterior of the bit body; a closure element for the passageway co-operating with the lower end of the bit body; and a bit-connecting means for releasably connecting the closure element to the bit body so as to selectively close the passageway; the well-drilling bit assembly further comprising an auxiliary tool for manipulating the closure element, which auxiliary tool is passable along the passageway in the bit body to the closure element when the bit body and closure element are interconnected with the bit-connecting means, which auxiliary tool comprises a tool-connecting means for selectively connecting the auxiliary tool to the closure element, and an operating means to operate the bit-connecting means which includes releasing the bit-connecting means, and which auxiliary tool comprises a first member which includes the tool-connecting means and a second member which includes the operating means, which second member is movably arranged relative to the first member so that it is movable between a first and a second position relative to the first member, wherein in the first position the tool-connecting means is connectable, at least when the bit body and closure element are interconnected with the bit-connecting means, to the closure element whereby the bit-connecting means is not operable, and whereby in connected condition of the auxiliary tool with the closure element the bit-connecting means is operable by movement of the second member including the operating means between the first and the second position.