Subsurface tubing safety valve

A subsurface tubing safety valve, comprising

• a tubular body adapted to be installed in a tubing string suspended within a well bore and having a flow way therethrough
• a closure member movable between body positions to open and close the flowway,
• means including a piston which, when the closure member is closed and in response to a predetermined differential pressure of well fluid across it, generates and stores energy for moving the closure member between its positions, and
• means operable in response to a predetermined change in the pressure differential across the piston for releasing a portion of the energy to move the closure member to open position, and
• means responsive to a predetermined increase in the rate of flow of the well fluid within the body for releasing further generated energy to move the closure member to closed position.

A subsurface tubing safety valve, comprising

• a tubular body adapted to be installed in a tubing string suspended within a well bore and having ports connecting its bore with the annulus about the body,
• a sleeve sealably reciprocable within the body between a lower position to open the ports and an upper position to close the ports,
• means including a piston sealably reciprocable within the sleeve between an upper limited position and a lower position and operable, when the sleeve is in its closed position and in response to a predetermined differential pressure of well fluid across the piston, to generate and store energy for moving the sleeve between its upper and lower positions,
• means operable, upon raising of the piston with respect to the sleeve, for releasably connecting the sleeve to the piston for downward movement with the piston, whereby, in response to a predetermined change in the pressure differential across the piston, generated energy is released to lower the sleeve with the piston to open the ports, and
• means which is responsive to a predetermined increase in the rate of flow of well fluid within the body, for releasing the connecting means and thereby permitting further generated energy to raise the sleeve to close the ports.

A subsurface tubing safety valve, comprising

• a tubular body adapted to be installed in a tubing string disposed in a well bore and having ports connecting its bore with the annulus about the body,
• a sleeve sealably slidable within the bore of the body between an upper position to close the ports and a lower position to open the ports,
• a piston sealably slidable within the sleeve between an upper limited position and a lower position,
• a closing spring acting between the piston and sleeve,
• an opening spring acting between the sleeve and body,
• said piston being raised to its upper limited position in response to a predetermined increase in the pressure differential of well fluid acting upwardly across it, when said sleeve is in its upper position to close the ports, whereby energy is generated and stored in both springs,
• means operable, upon raising of the piston with respect to the sleeve, for releasably connecting the sleeve to the piston for downward movement with piston, whereby, in response to a predetermined decrease in the pressure differential acting upwardly across the piston, energy generated in the opening spring is released to lower the sleeve with the piston to open the ports, and
• means responsive to a predetermined increase in the rate of flow of well fluid within the body, for releasing the connecting means and thereby permitting energy generated in the closing spring to raise the sleeve to close the ports.

A subsurface tubing safety valve, comprising

• a tubular body adapted to be installed in a tubing string suspended within a well bore and having a flowway therethrough,
• means including a closure member movable between positions opening and closing the flowway,
• means within the body and responsive to a predetermined differential pressure of well fluid across the closure member when in closed position for generating and storing energy for moving the closure member between opened and closed positions,
• means operable, in response to a predetermined change in the pressure differential of well fluid across said closure member to release a portion of the energy for moving said closure member to open position, and
• means which is expandable in response to a predetermined drop in pressure of the well fluid within the body for releasing further energy for moving the closure member to closed position.

A subsurface tubing safety valve, comprising

• a tubular body adapted to be installed in a tubing string suspended within a well bore and having a flow way therethrough
• a closure member movable between body positions to open and close the flowway,
• means including a piston which, when the closure member is closed and in response to a predetermined differential pressure of well fluid across it, generates and stores energy for moving the closure member between its positions,
• means operable responsive to a predetermined change in the pressure differential across the piston for releasing a portion of the energy to move the closure member to open position, and
• means which is expandable in response to a predetermined pressure drop in the well fluid within the body for releasing further generated energy to move the closure member to closed position.

A subsurface tubing safety valve, comprising

• a tubular body adapted to be installed in a tubing string suspended within a well bore and having ports connecting its bore with the annulus about the body,
• a sleeve sealably reciprocable within the body between a lower position to open the ports and an upper position to close the ports,
• means including a piston sealably reciprocable within the sleeve between an upper limited position and a lower position and operable, when the sleeve is in its closed position and in response to a predetermined differential pressure of well fluid across the piston, to generate and store energy for moving the sleeve between its upper and lower positions,
• means operable upon raising of the piston with respect to the sleeve for releasably connecting the sleeve to the piston for downward movement with the piston, whereby in response to a predetermined change in the pressure differential across the piston, generated energy is released to lower the sleeve with the piston to open the ports, and
• means which is expandable in response to a predetermined pressure drop in the well fluid within the body, for releasing the connecting means and thereby permitting further generated energy to raise the sleeve to close the ports.

A subsurface tubing safety valve, comprising

• a tubular body adapted to be installed in a tubing string disposed in a well bore and having ports connecting its bore with the annulus about the body,
• a sleeve sealably slidable within the bore of the body between an upper position to close the ports and a lower position to open the ports,
• a piston sealably slidable within the sleeve between an upper limited position and a lower position,
• a closing spring acting between the piston and sleeve,
• an opening spring acting between the sleeve and body,
• said piston being raised to its upper limited position, in response to a predetermined increase in the pressure differential of well fluid acting upwardly across it when said sleeve is in its upper position to close the ports, whereby energy is generated and stored in both springs,
• means operable upon raising of the piston with respect to the sleeve for releasably connecting the sleeve to the piston for downward movement with piston, whereby in response to a predetermined decrease in the pressure differential acting upwardly across the piston, energy generated in the opening spring is released to lower the sleeve with the piston to open the ports, and
• means which is expandable is in response to a predetermined pressure drop in the well fluid within the body for releasing the connecting means and thereby permitting energy generated in the closing spring to raise the sleeve to close the ports.