Patent US3621916A successfully refreshed from Google Patents.
US3621916A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spark-type casing perforator
Assignee: Shell USA Inc
•
Filing: 1969-10-08
•
Granted: 1971-11-23
•
Expires: 1989-10-08
Abstract
Abstract An electrical spark jet for perforating well casings and formations wherein a shaped spark discharge is used to form a jet of fluid. The electrodes for the shaped spark discharge comprise a center electrode and an outer cylindrical electrode with an insulator having a cone-shaped indentation being disposed between them. The insulator is coated with a thin conductive film and a cone-shaped metal liner is mounted along but spaced from the conductive film. The liner is coated with an insulation to insure that the spark discharge occurs between the two electrodes and not the metal liner and the conductive film. The electrical spark jet can also be used to detonate a thin cone of high explosive behind the conical metal liner in order to form a stronger jet without the total explosive effect that would occur if a sufficiently large weight of explosive was used to insure initiation and propagation of the detonation.
Inventors
- 👤 Noyes D Smith Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:38
CPC Classifications
F; F42; F42D; F42D3/00; E; E21; E21B; E21B29/00; E21B29/02; E21B43/00; E21B43/11; E21B43/116; E21B43/117; F42D1/00; F42D1/04; F42D1/045; F42D1/05
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
48 words
A process for perforating a casing disposed in a wellbore comprising: placing a generally cone-shaped metal liner adjacent the section of casing to be perforated; and creating a spark discharge within an airgap adjacent said metal liner to form a fluid jet and drive it through said casing.
Claim 2
Dependent Claim
48 words
A process for perforating a casing disposed in a wellbore comprising: placing a generally cone-shaped metal liner adjacent the section of casing to be perforated; and creating a spark discharge within an airgap adjacent said metal liner to form a fluid jet and drive it through said casing.
Claim 3
Dependent Claim
18 words
The process of claim 1 wherein said liner is positioned with its axis substantially perpendicular to the casing.
Claim 4
Dependent Claim
48 words
A perforating device for perforating well casings comprising: a cone-shaped metal liner, said liner being coated on its convex surface with an insulating film; at least two electrodes, said electrodes being disposed to form a cone-shaped spark discharge, said liner being mounted adjacent said electrodes and spaced therefrom.
Claim 5
Dependent Claim
48 words
A perforating device for perforating well casings comprising: a cone-shaped metal liner, said liner being coated on its convex surface with an insulating film; at least two electrodes, said electrodes being disposed to form a cone-shaped spark discharge, said liner being mounted adjacent said electrodes and spaced therefrom.
Claim 6
Dependent Claim
36 words
The perforating device of claim 3 wherein said pair of electrodes comprises: a central electrode and a cylindrical outer electrode, said outer electrode surrounding said central electrode; an insulator, said insulator being disposed between said electrodes.
Claim 7
Dependent Claim
30 words
The perforating device of claim 4 wherein said cylindrical electrode extends axially beyond said central electrode and said central electrode and said insulator is provided with a conically indented surface.
Claim 8
Dependent Claim
23 words
The perforating device of claim 5 wherein said insulator is provided with a thin conducting film that connects said central and cylindrical electrodes.
Claim 9
Dependent Claim
62 words
The perforating device of claim 6 wherein said liner and said insulator have substantially similarly shaped conical surfaces, said liner being axially spaced from said insulator to provide an airspace between said insulator and said liner and an insulating ring, said ring being positioned between the end of said cylindrical electrode and the outer periphery of the liner to enclose the airspace.
Claim 10
Dependent Claim
47 words
A perforating device for perforating well casings comprising: a cone-shaped metal liner, at least two electrodes, said electrodes being disposed to form a cone-shaped spark discharge, said liner being mouNted adjacent said electrodes and spaced therefrom, and explosive material is positioned between said insulator and said liner.
Claim 11
Dependent Claim
47 words
A perforating device for perforating well casings comprising: a cone-shaped metal liner, at least two electrodes, said electrodes being disposed to form a cone-shaped spark discharge, said liner being mouNted adjacent said electrodes and spaced therefrom, and explosive material is positioned between said insulator and said liner.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-22 | 1975-05-24 | 1975-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-22 | 1979-05-24 | 1979-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-22 | 1983-05-24 | 1983-11-23 | $7700.00 | Window Closed / Lapsed |