Schlumberger Technology Corporation

Pierre Chesnel

Alain P Pottier

Gerard Bouguyon

Jean C Lavigne

Bernard Chaintreau

The apparatus comprises an elongated support (22) having a series of flat-faced portions and explosive charges (23) mounted perpendicular to the flat faces. Detonating cords are connected to the charges to fire them. Each portion of the support has two closely spaced attachment holes adapted to receive respectively the rear parts of the two charges mounted in opposite directions on each face of this section. The support is made up of a tube flattened transversely so as to form the flat-faced portions. Spacers are disposed between the charges and the support for casings of large diameter. The cases of the charges comprise a cover made of ceramic material and an extruded steel body which tends to flare out when the explosive is detonated rather than being broken into pieces.

Well perforating apparatus

The apparatus comprises an elongated support (22) having a series of flat-faced sections and explosive charges (23) mounted perpendicular to the flat faces. Detonating cords are connected to the charges to fire them. Each section of the support has two closely spaced attachment holes adapted to receive respectively the rear parts of the two charges mounted in opposite directions on each face of this section. The support is made up of a tube flattened transversely so as to form the flat-faced sections. Spacers are disposed between the charges and the support for casings of large diameter. The cases of the charges comprise a cover made of ceramic material and an extruded steel body which tends to flare out when the explosive is detonated rather than being broken into pieces.

In the representative embodiment of the present invention disclosed herein, this new and improved perforating apparatus includes a plurality of encapsulated shaped explosive charges having their forward ends respectively fitted and threadedly secured in a facing relationship along the concave rear face of an elongated steel carrier strip of a unique design having its forward face complementally shaped for accommodation within a given size of well bore piping thereby allowing the largest possible mass of explosive to be disposed in each capsule. To assure the proper installation of the detonating cord, the rear portions of the two-part charge capsules are cooperatively arranged in a unique fashion so as to be rotatably positionable in relation to their forward portions for facilitating proper alignment of transversely-oriented cord-receiving openings provided in the base of each capsule.

Well bore perforating apparatus

In the representative embodiment of the present invention disclosed herein, this new and improved perforating apparatus includes a unique elongated carrier strip of a ductile steel carrying encapsulated shaped explosive charges having their forward ends fitted and snugly secured against the concave rear face of the strip by means of externally-threaded axial projections respectively threaded into tapped charge-mounting holes closely spaced along the carrier. The forward face of the carrier strip and the rear portions of the capsules are complementally shaped for accommodation within a given size of well bore piping thereby allowing the largest-possible mass of explosive to be disposed in each capsule. To assure that the new and improved perforating apparatus can be used safely in gas-filled well bores without risking either severe distortion or breakage of the carrier, additional openings are arranged in the strip between adjacent charge-mounting openings and cooperatively sized for preferentially inducing a minor transverse bend in the strip across each of these additional openings upon detonation of the adjacent charges instead of allowing the carrier to be severely bent in a substantially-uninterrupted arc or exaggerated bow along its full length.

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Savigny-sur-Orge, France

Pierre Chesnel