Patent ID: 6769490
Filing Date: 2004-08-03
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: 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; a sleeve within the housing assembly having an upper end and a lower end, and a set of flow ports formed therein, said sleeve being movable between an open port position where the set of flow holes of the housing assembly is aligned with the set of flow ports of the sleeve and a closed port position where the set of flow holes is blocked by the sleeve; and 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, an indexing mechanism to shift the sleeve from the open port position to the closed port position comprising: (i) a circumferential groove formed on the outer wall of the sleeve; (ii) a first circumferential groove formed on the inner wall of the housing assembly; (iii) a spring ring arranged within the circumferential groove of the sleeve, said spring ring being compressed when the sleeve is in the open port position and decompressed radially outward to engage the circumferential groove of the housing assembly when the sleeve is in the closed port position; (iv) connecting means for holding the sleeve in the open port position; and (v) actuating means for releasing the connecting means and for moving the sleeve from the open port position to the 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 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, wherein the connecting means comprises: a second circumferential groove formed on the inner wall of the housing assembly above the first circumferential groove of the housing assembly; a shear ring having an upper end and a lower end and an outer diameter less than the diameter of the axial bore of the housing assembly and an inner diameter greater than the diameter of the sleeve of the diverter device, said lower end of the shear ring engaging the second circumferential groove of the housing assembly; and a set of shear pins connecting the shear ring to the sleeve of the diverter device.