Patent ID: 7434625
Filing Date: 2008-10-14
Classification: E21B

Abstract:
1. A circulation tool for use downhole in a well, the circulation tool suspended in the well from a tubular string, the circulation tool comprising: a tubular housing including one or more bypass ports for circulation between a bore in the housing and an annulus surrounding the housing; a sleeve axially movable within the housing; axially spaced seals for sealing between the sleeve and the housing; a flapper above the one or more ports and including a seat about a central bore in the flapper for engagement with a plug; the sleeve being axially movable in response to fluid pressure above the flapper when engaged by the plug; and a stop movably responsive to an axial position of the sleeve for preventing pivoting of the flapper to an open position until the sleeve has moved axially and the axially spaced seals seal between the sleeve and the housing.