Patent ID: 6135215
Filing Date: 2000-10-24
Classification: E21B

Abstract:
A flexible tool string for advancing a drill bit while forming a lateral borehole which curves away from a vertical borehole and towards the horizontal, the vertical borehole having a casing extending through a production formation; said flexible tool string having a longitudinal central axis that can bend to conform to a segment of a curve; a longitudinally extending passageway formed axially through said flexible tool string; said flexible tool string being rotatably received within said casing with there being an annulus formed between the casing and tool string;a fluid conveying conduit made of resilient material within which there is received a fully collapsible tight wrapped spiral spring member having opposed ends, and includes a central axis that defines the axis of the longitudinal central passageway; said spring member forms an inner bendable member for preventing collapse of the inner wall of the fluid conveying conduit and thereby maintaining said central fluid conveying passageway in a fluid conveying configuration; said fully collapsible spring member being in the form of a coiled spring member that bears against the inner surface of said central fluid conduit;connector means affixed at opposed ends of the opposed ends of the spring member abuttingly engages the connector means fluid conveying conduit; whereby, rotational power imparted into one of the opposed connector means is transmitted by said coiled spring member into the other of the connector means.