Shaped charge tubing cutter
AssigneeSpecialty Completion Products, Inc.
InventorWilliam T. Bell
Life of this patent
Estimating the term…
Abstract
A shaped charge tubing cutter includes a minimal contact suspension to isolate the cutter explosive from the housing and sub structure. A charge detonation booster main-cavity is located on the juncture of the charge truncation planes. Explosive in the booster main-cavity is detonated by a shielded primer path. Explosive density in the primer path is less than the main-cavity density. A dense, powdered metal SC liner and an abruptly stepped jet window in the tubing cutter housing improve performance. The axial span of the jet window is preferably aligned with the axial span between the liner bases. A testing apparatus and procedure inexpensively verifies downhole performance.
Claims34
A shaped charge booster assembly comprising a casement having a primer path and a main cavity, said primer path being charged with an explosive material having a first density to link said main cavity with a booster ignition point, said main cavity being charged with an explosive material having a second density, an enclosure wall of said main cavity substantially opposite of said primer path being formed by an end plug.
A shaped charge booster assembly comprising a casement having a primer path circumscribed by a first casement wall thickness opening into a main cavity circumscribed by a second casement wall thickness that is less than said first wall thickness, said primer path and main cavity being respectively charged with explosive material, the explosive material charge in said primer path providing sufficient energy to detonate the explosive material in said main cavity but insufficient energy to propagate detonation of explosive material externally surrounding said first casement wall.
A shaped charge tubing cutter comprising a pair of substantially matched explosive units respectively formed about an axis of revolution into a substantial cone having a normally truncated apex, said units being joined coaxially at said truncated apex along a substantially common juncture plane, an aperture within said units substantially along said axis and crossing said juncture plane for receipt of a detonation booster, conical surface elements of said units being clad with a powdered metal liner comprising a mixture of tungsten, copper and lead.
A method of testing the performance of a shaped charge tubing cutter comprising the steps of:
- (a) selecting a plurality of metal test coupons having material properties corresponding to those of a test object tubing and a width that is greater than an object tubing wall thickness;
- (b) securing said coupons as radians about a circle corresponding to a circumference respective to a test subject cutter charge with said coupon width aligned radially;
- (c) securing a tubing cutter explosive assembly within said circle;
- (d) detonating said explosive assembly;
- and,
- (e) measuring an explosive jet penetration depth into said coupons.
A shaped charge tubing cutter comprising a pair of substantially matched explosive units respectively formed about an axis of revolution into substantial cones having a normally truncated apex, said cones being joined coaxially at said truncated apex along a common juncture plane, an aperture within said units substantially along said axis and crossing said juncture plane for receipt of a detonation booster, said explosive units being encased within a substantially cylindrical housing having circumferential lines of structural weakness adjacent base lines of said cones.
A shaped charge tubing cutter comprising a pair of substantially matched explosive units respectively formed about an axis of revolution into substantial cones having a normally truncated apex, said cones being joined coaxially at said truncated apex along a common juncture plane, an aperture within said units substantially along said axis and crossing said juncture plane for receipt of a detonation booster, said explosive units being suspended within a substantially cylindrical housing between opposing walls to provide a substantial void space between each of said walls and said units of about 0.100″ or more.
Dependencies are inferred from the claim text.