Baker Oil Tools, Inc.

John A Nelson

Gregg W Stout

John H Crisp

A separable fluid pressure activated firing mehanism for a perforating gun comprises a pressure-operated tubing valve, a packer, and a tubular housing assembly defining a plurality of fluid pressure chambers therein. The first chamber contains a light density, clean, compressible fluid which is subject to well annulus pressure above the packer to provide a reference pressure. A second chamber sealably mounts a piston-type firing pin, which is normally secured by a locked latch in an elevated position above a detonatable primer and the lower portion of said firing pin is exposed to the reference pressure. The latch is unlocked through the application of a predetermined annulus pressure above the packer to a locking piston which moves to unlock the latch and trap the reference pressure in the first chamber. A further increase in said annulus pressure opens the tubing valve. A still further increase in said annulus pressure releases the firing pin from the latch and drives the firing pin downwardly to detonate the primer. Additional features of the disclosure are the provision of a cross-over tool between the packer and the tubular housing assembly to permit underbalance perforating, the provision of a detachable connection between the cross-over tool and the packer, and the provision of a shiftable sleeve valve effecting the closing of a connection from the packer bore to the annulus upon disconnection of the packer from the cross-over tool.

Hydraulically activated firing head for well perforating guns

A separable fluid pressure activated firing mechanism for a perforating gun comprises a pressure-operated tubing valve, a packer, and a tubular housing assembly defining a plurality of fluid pressure chambers therein. The first chamber contains a light density, clean, compressible fluid which is subject to well annulus pressure above the packer to provide a reference pressure. A second chamber sealably mounts a piston-type firing pin, which is normally secured by a locked latch in an elevated position above a detonatable primer and the lower portion of said firing pin is exposed to the reference pressure. The latch is unlocked through the application of a predetermined annulus pressure above the packer to a locking piston which moves to unlock the latch and trap the reference pressure in the first chamber. A further increase in said annulus pressure opens the tubing valve. A still further increase in said annulus pressure releases the firing pin from the latch and drives the firing pin downwardly to detonate the primer. Additional features of the disclosure are the provision of a crossover tool between the packer and the tubular housing assembly to permit underbalance perforating, the provision of a detachable connection between the cross-over tool and the packer, and the provision of a shiftable sleeve valve effecting the closing of a connection from the packer bore to the annulus upon disconnection of the packer from the cross-over tool.

A redundant firing mechanism for a perforating gun utilized in subterranean wells comprises a hollow housing assembly incorporating two spaced primer charges disposed in vertically spaced relationship. A fluid pressure chamber is defined within the hollow housing assembly and is closed at the top end of the assembly by a frangible barrier disc. A fluid pressure actuated hammer is provided to impact upon the lowermost one of the primers in response to fluid pressure developed in the fluid pressure chamber. In the event that the lowermost primer does not detonate, a detonating bar may then be dropped through the tubing string to break the frangible barrier and impact upon a second hammer disposed in overlying relationship to the second primer.

Redundant firing mechanism for a well perforating gun

A method and apparatus for effecting the sealing of a well conduit comprises the positioning of a sealing plug unit within a special nipple provided in the well conduit and defining first and second surfaces and a seal bore. The sealing plug unit is provided with external seal elements cooperable with the seal bore and a first and second latching elements respectively cooperable with the first and second surfaces provided on the nipple. The sealing plug is actuated by first passing it downwardly through the nipple and then retracting it upwardly, whereupon the first of the latching elements engages with one of the surfaces on the nipple, thus preventing further upward movement on the assembly and permitting the application of a tensile force to release the plugging unit from the remainder of the unit to bring a camming sleeve into engagement with the second latching element to cam such element outwardly into engagement with an upper recess of the nipple. The sealing plug unit may be removed from the nipple through the application of applied force which effects the release of the camming sleeve holding latch elements in their locked position, thus permitting the sealing plug unit to be forced through the special nipple and discarded into the bottom of the well.

Perforation and isolation apparatus

The invention provides a subterranean well casing perforating gun device which employs shaped explosive charges to perforate the well casing. The device generally defines an outer tubular housing assembly concentrically insertable in the well and defining a vertical axis, cylindrical chamber. A tubular carrier of polygonal cross sectional configuration is insertable in the chamber in concentric relationship to the cylindrical wall of the cylindrical chamber. Each of the faces of the carrier have a plurality of spaced passages therethrough, each passage having a configuration substantially corresponding to the configuration of the polygonal face. A shaped charge container has its cylindrical body insertable in any selected one of the passages and a radial flange on the outer end for abutting the polygonal face portion adjacent the respective passage, thereby limiting the insertion of each of the containers into the selected passage. Selectively disengageable fastening means are operable from the exterior of the carrier for clamping the radial flange against the respective polygonal face and for selective disengagement therefrom from the exterior of the carrier. The invention also contemplates a method of utilization of the carrier and the gun, as well as to incorporation of same into a particular perforating and gravel packing method and apparatus.

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Spring, TX, United States of America

John A Nelson