Pressure controlled tester valve

Claim 2

A well tester apparatus, comprising: an elongated housing; a mandrel movable longitudinally in said housing; valve means opened in response to movement of said mandrel in one direction and closed in response to movement of said mandrel in the other direction; piston means on said mandrel sealingly slidable within cylinder means in said housing, said piston means normally having balanced pressures acting on opposite sides thereof; and means for admitting annulus well fluids to one side of said piston means to provide an unbalanced pressure thereon to cause shifting of said mandrel in said other direction and automatic closure of said valve means.

Claim 3

The apparatus of claim 1 wherein said admitting means includes port means in said housing for communicating a portion of said cylinder means with the well annulus, and blocking means normally closing said port means.

Claim 4

The apparatus of claim 2 wherein said blocking means comprises a shear plug extending into said cylinder means and providing a stop to longitudinal movement of said mandrel in said one direction, said plug being sheared off by a force of preselected magnitude on said mandrel acting in said one direction.

Claim 5

The apparatus of claim 3 wherein said piston means is arranged to engage said shear plug directly to apply said preselected magnitude of force thereto.

Claim 6

Apparatus adapted for use in a fluid-filled well bore, comprising: normally closed test valve means adapted to be opened in response to an operating pressure applied to fluids in the well annulus, said valve means including a mandrel movable longitudinally within a housing; piston means on said mandrel slidably engaged in cylinder means on said housing, said piston means having oppositely facing pressure surfaces; means for isolating said oppositely facing pressure surfaces from the pressure of fluids in the well annulus; and means responsive to a value of pressure in excess of said operating pressure to permit the pressure of fluids in the well annulus to act on one said pressure surfaces of said piston means to thereby shift said mandrel in a direction to cause closure of said valve means.

Claim 7

Apparatus adapted for use in a fluid-filled well bore, comprising: normally closed test valve means adapted to be opened in response to an operating pressure applied to fluids in the well annulus, said valve means including a mandrel movable longitudinally within a housing; piston means on said mandrel slidably engaged in cylinder means on said housing, said piston means having oppositely facing pressure surfaces; means for isolating said oppositely facing pressure surfaces from the pressure of fluids in the well annulus; and means responsive to a value of pressure in excess of said operating pressure to permit the pressure of fluids in the well annulus to act on one said pressure surfaces of said piston means to thereby shift said mandrel in a direction to cause closure of said valve means.

Claim 8

The apparatus of claim 5 wherein said isolating means includes a flow port in said housing, and means extending into said cylinder means for blocking said flow port.

Claim 9

The apparatus of claim 6 wherein said blocking means is a frangible plug arranged to be engaged by said piston means and broken off by a predetermined amount of longitudinal force on said mandrel to open said flow port.

Claim 10

A fluid pressure controlled well tester apparatus, comprising: housing means having a flow passage extending therethrough; pressure responsive valve means movable between positions closing and opening said flow passage; chamber means containing a compressible fluid medium, said valve means including a mandrel having first piston means with one side thereof subject to the pressure of fluids in the well annulus externally of said housing means and the other side subject to the pressure of said fluid medium; means for equalizing the pressure of said fluid medium with the hydrostatic head of the well fluids externally of said housing means; selectively operable means for closing said equalizing means so that pressure applied to the fluid externally of said housing means subsequent to the closing of said equalizing means can act on said one side of said first piston means to move said mandrel in one longitudinal direction to cause opening of said valve means; second piston means on said mandrel sealingly slidable within cylinder means in said housing means, said second piston means normally having balanced pressures acting on opposite sides thereof; and means responsive to an excessive pressure of the fluids in the well annulus externally of said housing means for admitting well fluids to one side of said second piston means to provide an unbalanced pressure that functions to cause shifting of said mandrel in the opposite longitudinal direction and results in closing of said valve means.

Claim 11

A fluid pressure controlled well tester apparatus, comprising: housing means having a flow passage extending therethrough; pressure responsive valve means movable between positions closing and opening said flow passage; chamber means containing a compressible fluid medium, said valve means including a mandrel having first piston means with one side thereof subject to the pressure of fluids in the well annulus externally of said housing means and the other side subject to the pressure of said fluid medium; means for equalizing the pressure of said fluid medium with the hydrostatic head of the well fluids externally of said housing means; selectively operable means for closing said equalizing means so that pressure applied to the fluid externally of said housing means subsequent to the closing of said equalizing means can act on said one side of said first piston means to move said mandrel in one longitudinal direction to cause opening of said valve means; second piston means on said mandrel sealingly slidable within cylinder means in said housing means, said second piston means normally having balanced pressures acting on opposite sides thereof; and means responsive to an excessive pressure of the fluids in the well annulus externally of said housing means for admitting well fluids to one side of said second piston means to provide an unbalanced pressure that functions to cause shifting of said mandrel in the opposite longitudinal direction and results in closing of said valve means.

Claim 12

The apparatus of claim 8 when said admitting means comprising port means in the wall of said cylinder means adjacent said one side of said second piston means, and blocking means normally closing said port means to prevent the pressure of fluids externally of said housing means from acting on said one side of said second piston means.

Claim 13

The apparatus of claim 9 when said blocking means extends into said cylinder means and is arranged to be engaged by said second piston means to provide a stop against longitudinal movement of said mandrel in said one direction.

Claim 14

The apparatus of claim 10 when said blocking means has a breakable portion positioned for engagement by said second piston means, breakage of said portion opening said port means in response to said excessive pressure acting on said one side of said first piston means with the resulting force being transmitted by said second piston means to said portion.

Claim 15

The apparatus of claim 11 wherein said one side of said first piston means and one side of said second piston means face in opposite longitudinal directions.