Apparatus for releasing, then firing perforating guns
AssigneeBaker Hughes Incorporated
InventorsTimothy W. Sampson, Wilfred Schexnayder, Colby W. Ross
Life of this patent
Estimating the term…
Abstract
A perforating gun can be conveyed on tubing and fired while disconnected from the tubing. The gun is retained to a running tool at the lower end of the tubing in a locked position. Actuating a plunger by pressure, a weight bar or other techniques, breaks a rupture disc and allows use of hydrostatic pressure to stroke a piston and defeat the lock between the gun and the running tool. Upon exposure of ports on the gun to wellbore hydrostatic due to movement out of the running tool, the firing sequence in the gun is initiated. The weight of the gun, as well as hydrostatic or applied pressure in the wellbore, drives the perforating gun out of the running tool.
Claims23
A downhole perforating gun firing apparatus, comprising:
- a running tool having a body;
- a gun body having a firing assembly adjacent an upper end thereof selectively retained by said running tool body by a lock;
- whereupon when said lock is unlocked without any firing of said firing assembly, said gun body is no longer supported by said running tool body and it falls with respect to said running tool body, said falling of said gun body with respect to said running tool body sufficiently to expose said firing assembly to downhole hydrostatic pressure, sets off said firing assembly without gun impact on a fixed object downhole.
A downhole perforating gun firing apparatus, comprising:
- a running tool having a body;
- a gun body having a firing assembly selectively retained by said running tool body by a lock;
- whereupon when said lock is unlocked, said gun body moves with respect to said running tool body in order to actuate said firing assembly;
- said running tool comprises a receptacle which is selectively engaged by said gun body in a manner where access to said firing assembly is prevented;
- said gun body is held to said receptacle by a dog extending through a window in an external tubular extension of said gun body while engaging in recess in said receptacle;
- an internal tubular extension of said gun body to define an annulus between itself and said external tubular extension;
- a piston in said annulus movable from a first position where it holds said dog to said recess and a second position where it allows said dog to move out of said recess.
A method of firing a perforating gun having an upper end in a wellbore, comprising:
- running in the gun on a running tool;
- locating a firing mechanism for the gun adjacent said upper end;
- releasing the gun so that it can drop from the running tool;
- exposing said firing mechanism to wellbore hydrostatic pressure;
- firing the gun as a result of said exposure to hydrostatic pressure.
A method of firing a perforating gun in a wellbore, comprising:
- running in the gun on a running tool;
- releasing the gun from the running tool;
- firing the gun as it moves with respect to the running tool;
- providing a receptacle in the running tool;
- locking the gun body to the receptacle for run-in;
- covering up an access port to a firing assembly by the receptacle during run-in;
- uncovering the access port as the gun moves out of the receptacle;
- using hydrostatic pressure through the uncovered port to fire the firing assembly.
A method of firing a perforating gun in a wellbore, comprising:
- running in the gun on a running tool;
- releasing the gun from the running tool;
- firing the gun as a result of its movement with respect to the running tool;
- providing a receptacle in the running tool,
- locking the gun body to the receptacle for run-in;
- covering up an access port to a firing assembly by the receptacle during run-in;
- uncovering the access port as the gun moves out of the receptacle;
- using a dog trapped by a movable piston to selectively lock the gun body to the receptacle;
- selectively isolating the piston from wellbore hydrostatic pressure until a barrier is broken;
- applying an unbalanced force to the piston using wellbore hydrostatic pressure when the barrier is broken.
- undermining the dog to release the gun body by moving the piston.
Dependencies are inferred from the claim text.