Fail safe surface controlled subsurface safety valve for use in a well

A fail-safe, surface controlled subsurface safety valve for use in a well, comprising:

• a valve body having a longitudinal bore for fluid to flow through, a bore closure assembly, a pressure balanced drive assembly, and a fail safe assembly;
• the bore closure assembly being positioned and normally biased to close the bore to fluid flow;
• the pressure balanced drive assembly coupled to the bore closure assembly for driving the bore closure assembly to an open position;
• the fail safe assembly being positioned and configured to hold the bore closure assembly in the open position in response to a hold signal and to release the valve to return to the safe, closed position upon interruption of the hold signal;
• and
• wherein the pressure balanced drive assembly comprises a hydraulic actuator coupled to the bore closure assembly by a mechanical linkage and is configured such that the driving force need only overcome the resistance force that normally biases the bore closure assembly to the closed position.

A fail-safe, surface controlled subsurface safety valve for use in a well, comprising:

• a valve body having a longitudinal bore for fluid to flow through, a bore closure assembly, a pressure balanced drive assembly, and a fail safe assembly;
• the bore closure assembly being positioned and normally biased to close the bore to fluid flow;
• the pressure balanced drive assembly coupled to the bore closure assembly for driving the bore closure assembly to an open position;
• the fail sate assembly being positioned and configured to hold the bore closure assembly in the open position in response to a hold signal and to release the valve to return to the safe, closed position upon interruption of the hold signal;
• wherein the pressure balanced drive assembly comprises a hydraulic actuator coupled to the bore closure assembly by a mechanical linkage and
• wherein the hydraulic actuator and at least a portion of the mechanical linkage are housed within a sealed chamber filled with an incompressible fluid and the pressure of the incompressible fluid is balanced with the wellbore pressure by at least one bellows connected to the scaled chamber.

A fail-sale, surface controlled subsurface safety valve for use in a well, comprising:

• a valve body having a longitudinal bore for fluid to flow through, a bore closure assembly, a pressure balanced drive assembly, and a fail safe assembly;
• the bore closure assembly being positioned and normally biased to close the bore to fluid flow;
• the pressure balanced drive assembly coupled to the bore closure assembly for driving the bore closure assembly to an open position;
• the fail safe assembly being positioned and configured to hold the bore closure assembly in the open position in response to a hold signal and to release the valve to return to the safe, closed position upon interruption of the hold signal;
• wherein the pressure balanced drive assembly comprises a hydraulic actuator coupled to the bore closure assembly by a mechanical linkage;
• wherein the mechanical linkage further comprises a shaft;
• wherein the hydraulic actuator further comprises an electric pump for pumping the incompressible fluid in a hydraulic loop and applying a driving force to the shaft and a control valve for regulating the pressure in the hydraulic loop;
• and
• wherein the hydraulic actuator and an least a portion of the shall are housed within a scaled chamber filled with an incompressible fluid and the pressure of the incompressible fluid is balanced with the wellbore pressure by at least one bellows connected to the sealed chamber.

A fail-safe, surface controlled subsurface safety valve for use in a well, comprising:

• a valve body having a longitudinal bore for fluid to flow through, a bore closure assembly, a pressure balanced drive assembly, and a fail safe assembly;
• the bore closure assembly being positioned and normally biased to close the bore to fluid flow;
• the pressure balanced drive assembly coupled to the bore closure assembly the driving the bore closure assembly to an open position;
• the fail safe assembly being positioned and configured to hold the bore closure assembly in the open position in response to a hold signal and to release the valve to return to the safe, closed position upon interruption of the hold signal;
• wherein the pressure balanced drive assembly comprises a hydraulic actuator coupled to the bore closure assembly by a mechanical linkage;
• wherein the mechanical linkage further comprises a shaft;
• wherein the hydraulic actuator further comprises an electric pump for pumping the incompressible fluid in a hydraulic loop and applying a driving force to the shaft and a control valve for regulating the pressure in the hydraulic loop;
• and
• wherein the hydraulic actuator is housed within a sealed chamber filled with an incompressible fluid and the shaft is not housed within the sealed chamber, and the pressure of the incompressible fluid is balanced with the wellbore pressure by at least one bellows connected to the sealed chamber.

A fail-safe, surface controlled subsurface safety valve for use in a well, comprising:

• a valve body having a longitudinal bore for fluid to flow through, a bore closure assembly, a pressure balanced drive assembly, and a fail safe assembly;
• the bore closure assembly being positioned and normally biased to close the bore to fluid flow;
• the pressure balanced drive assembly coupled to the bore closure assembly for driving the bore closure assembly to an open position;
• the fail safe assembly being positioned and configured to hold the bore closure assembly in the open position in response to a hold signal and to release the valve to return to the safe, closed position upon interruption of the hold signal;
• wherein the pressure balanced drive assembly further comprises an electric motor coupled to the bore closure assembly by a mechanical linkage;
• wherein the fail safe assembly selected from the group consisting of a piezoelectric device, an electrostrictive device, and a magnetorestrictive device is operable upon the mechanical linkage such that upon engagement, a movable member of the mechanical linkage is locked into place;
• and
• wherein the fail safe assembly selected from the group consisting of a piezoelectric device, an electrostrictive device, and a magnetostrictive device further comprises a band surrounding the movable member and at least one end of the band connected to a deformable member selected respectively from the group consisting of a piezoelectric stack, an electrostrictive stack, and a magnetostrictive actuator, the deformable member having an electrical connection, the fail safe assembly being configured such that upon application of an electrical signal to the electrical connection, the deformable member deforms, thereby tightening the band around the movable member and locking the movable member into place against a stator.

A fail-safe, surface controlled subsurface safety valve for use in a well, comprising:

• a valve body having a longitudinal bore for fluid to flow through, a bore closure assembly, a pressure balanced drive assembly, and a fail safe assembly;
• the bore closure assembly being positioned and normally biased to close the bore to fluid flow;
• the pressure balanced drive assembly coupled to the bore closure assembly for driving the bore closure assembly to an open position;
• the fail safe assembly being positioned and configured to hold the bore closure assembly in the open position in response to a hold signal and to release the valve to return to the safe, closed position upon interruption of the hold signal;
• wherein the pressure balanced drive assembly comprises a hydraulic actuator coupled to the bore closure assembly by a mechanical linkage;
• and
• wherein the fail safe assembly selected from the group consisting of a piezoelectric device, an electrostrictive device, and a magnetostrictive device further comprises a band surrounding the movable member and at least one end of the band connected to a deformable member selected respectively from the group consisting of a piezoelectric stack, an electrostrictive stack, and a magnetostrictive actuator, the deformable member having an electrical connection, the fail safe assembly being configured such that upon application of an electrical signal to the electrical connection, the deformable member deforms, thereby tightening the band around the movable member and locking the movable member into place against a stator.

A fail-safe, surface controlled subsurface safety valve for use in a well, comprising:

• a valve body having a longitudinal bore for fluid to flow through, a bore closure assembly, a pressure balanced drive assembly, and a fail safe assembly;
• the bore closure assembly being positioned and normally biased to close the bore to fluid flow;
• the pressure balanced drive assembly coupled to the bore closure assembly for driving the bore closure assembly to an open position;
• the fail safe assembly being positioned and configured to hold the bore closure assembly in the open position in response to a hold signal and to release the valve to return to the safe, closed position upon interruption of the hold signal;
• wherein the pressure balanced drive assembly further comprises a linear induction motor generating a magnetic field that actuates the bore closure assembly;
• and
• wherein the fail safe assembly selected from the group consisting of a piezoelectric device, an electrostrictive device, and a magnetostrictive device further comprises a band surrounding the movable member and at least one end of the band connected to a deformable member selected respectively from the group consisting of a piezoelectric stack, an electrostrictive stack, and a magnetostrictive actuator, the deformable member having an electrical connection, the fail safe assembly being configured such that upon application of an electrical signal to the electrical connection, the deformable member deforms, thereby tightening the band around the movable member and locking the movable member into place against a stator.