Pressure actuated ported sub for subterranean cement completions

A valve for subterranean use, comprising:

• a housing having a passage therethrough and a port in a wall thereof;
• a sleeve having a flow path therethrough movably mounted in said housing between a first position where said port is closed and a second position where said port is at least in part open;
• a piston associated with said sleeve for moving said sleeve, said piston selectively isolated from passage pressure until a predetermined pressure is reached;
• said piston has a first side that is selectively exposed to passage pressure and a second side opposite said first side exposed to a closed chamber in said housing;
• said first side of said piston is exposed to a second chamber in said housing.

A valve for subterranean use, comprising:

• a housing having a passage therethrough and a port in a wall thereof;
• a sleeve having a flow path therethrough movably mounted in said housing between a first position where said port is closed and a second position where said port is at least in part open;
• a piston associated with said sleeve for moving said sleeve, said piston selectively isolated from passage pressure until a predetermined pressure is reached;
• said sleeve is retained with a selectively defeated retainer until such time as said piston is no longer isolated from passage pressure.

A valve for use in a cementable open-hole well comprising:

• a housing having a passage therethrough and a port in a wall thereof for providing access from an interior of said housing to an exterior of the housing;
• a sleeve having a longitudinal flow path therethrough movably mounted in said passage of said housing, the sleeve being movable from an initial closed position to an open position;
• wherein when said sleeve is in said closed position the interior of said housing is isolated from the exterior of said housing and wherein when said sleeve is in said open position the port provides access from the interior of the housing to the exterior of the housing;
• and
• a piston associated with said sleeve for moving said sleeve from the initial closed position to the open position, said piston selectively isolated from pressure within the passage until a predetermined pressure within the passage is reached.

A method of temporarily isolating the inside of a valve from an open-hole well comprising:

• running a valve connected to casing into an open-hole well, the valve including a housing having a passage therethrough and a port in a wall of the housing, and a sleeve positioned within the passage and movable upon exposure to a predetermined passage pressure from an initial closed position that covers the port to an open position that uncovers at least a portion of the port;
• exposing the sleeve to the predetermined passage pressure;
• and
• moving the sleeve from the initial closed position to the open position.