Patent ID: 6695066
Filing Date: 2004-02-24
Classification: E21B

Abstract:
Apparatus for use in reducing surge pressure while running a tubular member through a borehole containing drilling fluid using a drilling rig, said apparatus comprising:a drill pipe for communication between the drilling rig and the borehole, said drill pipe comprising an upper end operatively connected to the drilling rig and a lower end, a diverter device for directing flow of drilling fluid, said diverter device comprising: (i) a housing assembly having an upper end operatively connected to the lower end of the drill pipe and a lower end, said housing assembly having a set of flow holes formed therein; (ii) a sleeve within the housing assembly having an upper end and a lower end, said sleeve being movable between an open port position where the set of flow holes is not blocked by the sleeve and a closed port position where the set of flow holes is blocked by the sleeve; and (iii) means to shift the sleeve downward from an open port position to a closed port position, said means displacing a predetermined volume of drilling fluid to shift the sleeve downward from an open port position to a closed port position, and a volume compensation device which, when activated, accumulates a volume of drilling fluid equal to or greater than the volume of drilling fluid which is displaced when the sleeve of the diverter device is shifted downward from an open port position to a closed port position, said volume compensation device having an upper end operatively connected to the diverter device and a lower end operatively connected to the tubular member.