Robert M Dutton

US Patent:

42769370, Jul 7, 1981

Filed:

Feb 7, 1979

Appl. No.:

6/009869

Inventors:

Michael B. Calhoun - Carrollton TX
Russell I. Bayh - Carrollton TX
Robert E. Dutton - Aurora CO

Assignee:

Otis Engineering Corporation - Dallas TX

International Classification:

E21B 4312

US Classification:

166323

Abstract:

A well safety system for controlling the flow of fluid through well conduits. The system includes a surface controlled subsurface safety valve made up as part of a tubing string extending from the well surface to a subsurface formation within a casing string. A packer, installed below the safety valve, forms a fluid tight seal between the tubing and casing to direct fluid from below the packer into the tubing. The safety valve contains lateral passageways which allow communication of fluid from the bore of the safety valve to the annulus between the tubing and casing above the packer. A valve actuator is releasably secured within the upper portion of the safety valve and forms a fluid tight seal between control fluid pressure in the tubing string above the safety valve and formation fluid pressure in the tubing string below the safety valve. The safety valve can be locked open when control pressure is increased above a preselected value and then released. The safety valve can be unlocked by returning control pressure to another preselected value.