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US 8,910,556 B2Granted
Bottom hole firing head and method
OwnerDon Umphries, Gabe Willigerinventors
Life of this patent
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Abstract
Detonation of a perforating gun is initiated by engagement of the lower distal end of the gun assembly against a bottom hole bore plug. A fluid pressure actuated firing head is initiated by well fluid that is pressurized by a free piston having an integral rod projecting from the distal end of the gun assembly. The piston is displaced against a closed fluid volume when the projecting rod engages the bore plug.
Claims7
An explosive detonation sub for detonating explosive well tools, said sub comprising:
- a cylindrical housing having an axially open fluid path between a detonator end and a piston end including a piston bore;
- an axially translated piston within said piston bore that is resiliently biased toward a distal end of said piston bore;
- a percussion detonator proximate of said detonator end;
- a firing pin displaced by a fluid pressure pulse in said fluid path for detonating said detonator;
- and
- a piston rod projected from a piston end of said housing for displacing said piston to generate a fluid pressure pulse in said fluid path;
- and,
- a first aperture through a housing wall into said piston bore to vent a predetermined volume of fluid upon displacement of said piston prior to generation of said pressure pulse.
5 more elements
A method of detonating an explosive down hole well tool
- comprising the steps of:
- coupling a firing head to a down hole end of an explosive well tool;
- providing said firing head with a percussion detonator and a fluid pressure driven firing pin for striking said detonator;
- coupling a cylinder sub to a down hole end of said firing head;
- providing a piston in said cylinder sub to displace fluid into a fluid link with said firing pin;
- providing a resilient bias against said piston;
- providing a projection from said piston to project past a down hole distal end of said cylinder sub;
- providing a first vent from said fluid link to discharge a predetermined volume of fluid displaced by an initial translation of said piston against said resilient bias due to engagement of said projection with a well bore obstacle;
- and,
- generating firing pin driving pressure in said fluid link after discharging said predetermined volume of fluid.
7 more elements
Dependencies are inferred from the claim text.