Patent ID: 6095250
Filing Date: 2000-08-01
Classification: E21B

Abstract:
A remedially deployable subsurface valve assembly comprising:a first tubing string deployed in a hydrocarbon production wellbore extending beneath an earthen surface, wherein said first tubing string defines a first tubing string exterior having an outside diameter and a first tubing string interior having an inside diameter;a first safety valve positioned in said first tubing string, said first safety valve having a first valve member selectively displaceable between a first valve opened position and a first valve closed position;a second tubing string deployed in said first tubing string interior, wherein said second tubing string defines a second tubing string exterior having an outside diameter and a second tubing string interior having an inside diameter, further wherein said outside diameter of said second tubing string exterior is substantially less than said inside diameter of said first tubing string interior to define an annulus between said first and second tubing strings;a second safety valve positioned in said second tubing string and nested within said first safety valve, said second safety valve having a housing enclosing a second valve member selectively displaceable between a second valve opened position and a second valve closed position, wherein said housing is adjacent to said first valve member in said annulus between said first and second tubing strings, said housing substantially blocking selective displacement of said first valve member to said first valve closed position, thereby rendering said first valve member substantially fixed in said first valve opened position; anda seal positioned in said annulus between said first and second tubing strings to block fluid flow through said annulus at said seal, wherein said seal defines a pressurizable segment of said annulus in communication with said second safety valve for transitioning said second valve member between said second valve opened position and said second valve closed position.