| (11) | EP 0 223 552 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Downhole circulation valve and method for operating the same |
(57) A pressure operated downhole circulation valve comprises a cylindrical housing having an open longitudinal passageway (216) therethrough and a circulation port (252) disposed through a wall thereof. A valve mandrel (218) is slidably received in the housing and is movable between a position in which fluid may be circulated only between the passageway and the exterior of the housing, a position in which fluid may be circulated only between the exterior of the housing and the passageway (illustrated), and a position in which fluid may not be circulated in either direction. An annular piston (270) is operatively connected to the valve mandrel and has a first side exposed to pressure exterior of the housing and a second side exposed to pressure interior of the housing to permit movement of the valve mandrel to its various positions by application of pressure to the interior and exterior of the housing. |