초록 ▼

The current invention provides improved methods and compositions for completing a well bore. In one aspect, the current invention provides a process for preparing a foamed cement composition. The process utilizes air to foam the cement after the air has been treated to lower the oxygen content below

The current invention provides improved methods and compositions for completing a well bore. In one aspect, the current invention provides a process for preparing a foamed cement composition. The process utilizes air to foam the cement after the air has been treated to lower the oxygen content below that concentration necessary to support combustion. Additionally, the current invention provides a process for completing a well bore using foamed cement wherein the foam is generated with reduced oxygen content air. Finally, the current invention provides a foamed cement composition wherein the gaseous portion of the composition is air having a reduced oxygen content.

대표청구항 ▼

The current invention provides improved methods and compositions for completing a well bore. In one aspect, the current invention provides a process for preparing a foamed cement composition. The process utilizes air to foam the cement after the air has been treated to lower the oxygen content below

The current invention provides improved methods and compositions for completing a well bore. In one aspect, the current invention provides a process for preparing a foamed cement composition. The process utilizes air to foam the cement after the air has been treated to lower the oxygen content below that concentration necessary to support combustion. Additionally, the current invention provides a process for completing a well bore using foamed cement wherein the foam is generated with reduced oxygen content air. Finally, the current invention provides a foamed cement composition wherein the gaseous portion of the composition is air having a reduced oxygen content. afe assembly further comprising a field generating means selected respectively from the group consisting of a means for applying a magnetic field to the magnetorheological fluid or a means for applying an electrical field to the electrorheological fluid, the field generating means being configured such that upon application of the respective field a moving member of the mechanical linkage is locked into place. 12. The valve of claim 1 wherein the fail safe assembly further comprises an electromagnetic clutch and an anti-backdrive device connected to and positioned between the pressure balanced drive assembly and the bore closure assembly. 13. The valve of claim 12 wherein the anti-backdrive device is selected from the group consisting of a sprag clutch, a non-backdriveable gear reducer, an electromagnetic brake, a spring-set brake, a permanent magnet brake on the electric motor, a means for holding power on the electric motor, a locking member, a piezoelectric device, and a magnetorheological (MR) device. 14. The valve of claim 13 wherein the anti-backdrive device is a locking member selected from the group consisting of a latch, a cam, a pin, and a wrap spring. 15. The valve of claim 1 wherein the fail safe assembly further comprises a locking member selected from the group consisting of a latch, a cam, a pin, and a wrap spring. 16. The valve of claim 1 wherein the fail safe assembly is selected from the group consisting of a piezoelectric device, an electrostrictive device, and a magnetostrictive device. 17. The valve of claim 1 wherein the fail safe assembly is selected from the group consisting of a magnetorheological device and an electrorheological device. 18. The valve of claim 1 wherein the bore closure assembly further comprises a flapper valve, the flapper valve being held in the open position by a flow tube. 19. The valve of claim 18 further comprising a feedback loop sensing the position of the flow tube and communicating the position to the drive assembly. 20. The valve of claim 1 wherein the bore closure assembly further comprises a ball valve. 21. The valve of claim 20 further comprising a feedback loop sensing the position the ball valve and communicating the position to the drive assembly. 22. The valve of claim 1 further comprising a means for sensing the position of the bore closure assembly and communicating the position to the drive assembly. 23. The valve of claim 22 wherein the sensing means is an electrical current monitor monitoring the drive assembly, wherein a spike in current indicates that the drive assembly has driven the bore closure assembly to a limit. 24. The valve of claim 22 wherein the sensing means is driving cycle counter monitoring the drive assembly, wherein the number of driving cycles is calibrated to the position of the bore closure assembly. 25. The valve of claim 1 wherein the hold signal consumes less than about 10 watts. 26. The valve of claim 25 wherein the hold signal is transmitted through a wire. 27. The valve of claim 25, wherein the hold signal is a wireless transmission. 28. The valve of claim 1 wherein the valve closes in less than about 5 seconds upon interruption of the hold signal. 29. The valve of claim 1 wherein the valve is insensitive to the depth at which it is installed in the well. 30. 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 inter ruption 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. 31. The valve of claim 30 wherein the mechanical linkage further comprises a shaft. 32. The valve of claim 31 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. 33. The valve of claim 32 wherein the control valve is selected from the group consisting of a solenoid valve, a spring-biased check valve, and a flow switch. 34. The valve of claim 33 wherein the incompressible fluid is selected from the group consisting of a magnetorheological fluid and an electrorheological fluid and wherein the flow switch respectively applies a magnetic field to the magnetorheological fluid or an electrical field to the electrorheological fluid such that upon application of the respective filed a moving member of the shaft is locked into place. 35. The valve of claim 32 wherein power is supplied to the electric pump by inductive coupling. 36. The valve of claim 32, wherein the hydraulic actuator and at least a portion of the shaft 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 piston connected to the sealed chamber. 37. The valve of claim 32 wherein the hydraulic actuator is housed within a sealed chamber filled with an incompressible fluid and the shaft is not housed within the scaled chamber, and the pressure of the incompressible fluid is balanced with the wellbore pressure by at least one piston connected to the sealed chamber. 38. The valve of claim 30 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 thc wellbore pressure by at least one piston connected to the sealed chamber. 39. The valve of claim 8 wherein the fail safe assembly further comprises a locking member selected from the group consisting of a latch, a cam, a pin, and a wrap spring. 40. The valve of claim 30 wherein the fail safe assembly selected from the group consisting of a magnetorheological device and an electrorheological device is operable upon the mechanical linkage such that upon engagement, a movable member of the mechanical linkage is locked into place. 41. 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. 42. The valve of claim 41 wherein the incompressible fluid is selected from the group consistin g of a magnetorheological fluid and an electrorheological fluid, and the fail safe assembly further comprising a field generating means selected respectively from the group consisting of a means for applying a magnetic field to the magnetorheological fluid or a means for applying an electrical field to the electrorheological fluid, the field generating means being configured such that upon application of the respective field a moving member of the mechanical linkage is locked into place. 43. 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. 44. 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. 45. The valve of claim 44, wherein the incompressible fluid is selected from the group consisting of a magnetorheological fluid and an electrorheological fluid, and the fail safe assembly further comprising a field generating means selected respectively from the group consisting of a means for applying a magnetic field to the magnetorheological fluid or a means for applying an electrical field to the electrorheological fluid, the field generating means being configured such that upon application of the respective field a moving member of the mechanical linkage is locked into place. 46. A fail-safe,