Patent Application
20100139515
The present specification relates in general to wellbore operations and more specifically to shaped charges.
A perforating device or perforating gun may be utilized in a subterranean well to perforate a well casing and surrounding formation. For example, once a well is drilled, a well casing may be inserted into the well and cemented into place. A perforating gun may be inserted into the well and shaped charges may be detonated to punch holes in the well casing and surrounding formation. A shaped charge may include a liner surrounded by a case to enclose explosive materials. When the explosive materials are detonated in shaped charges, the liner portion forms a slug and a jet that is propelled through the well casing and into the formation and may create a perforation tunnel. Heretofore, the liner and the case for the shaped charges are manufactured separately utilizing two or more different non-integral or non-unitary parts for the case and the liner.
An embodiment of a shaped charge includes a shaped charge comprising: a body comprising a liner portion and a case portion; the case portion and the liner portion together being a single unitary piece of shaped charge material; the case portion and the liner portion defining a chamber between the case portion and the liner portion; and an explosive material disposed within the chamber.
The foregoing has outlined some of the features and technical advantages of embodiments in order that the detailed description of the embodiments that follow may be better understood. Additional features and advantages will be described hereinafter which form the subject of the claims herein.
The foregoing and other features and aspects of embodiments will be best understood with reference to the following detailed description of specific embodiments, when read in conjunction with the accompanying drawings, wherein:
Refer now to the drawings wherein depicted elements are not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views.
Liner portion 16 is a generally bowl, or coned, shaped section that may shape the perforating jet of the detonated explosive 14. For purposes of description, liner portion 16 forms a cavity 20 extending from a face 22 of shaped charge 10 to a tip or apex 24. Case portion 18 is the portion of body 12 that extends around from face 22 proximate to apex 24. Explosive 14 is disposed in a chamber 26 formed between liner portion 16 and case portion 18.
A hole 28 may be formed through case portion 18 into chamber 26. Hole 28 may be utilized, for example, for disposing explosive 14 in chamber 26 and for positioning and/or exposing a primer 30 (
An embodiment of a method of constructing a shaped charge 10 of the present invention is described with reference to
In this embodiment, material 32 is provided as a substantially planar member that is a single unitary part and is circular in shape. In a first step, liner portion 16 is formed from the material 32 into substantially the desired profile and dimensioned to achieve the desired liner portion 16 shape. For example, in this embodiment, liner portion 16 is formed to have a triple radius formed as it extends down from a face 22 down to its tip 24. For example, there can be at least three distinct radiuses of curvature from the face 22 to the tip 24, possibly as part of a progressive change of curvature, akin to tapering. Ballistic characteristics can be affected from varying the shape of the liner portion. Further, as in this embodiment liner portion 16 can have a progressively changing thickness, e.g., tapering, wherein its thickness decreases as it extends from about face 22 toward tip 24. Similarly, the thickness of the liner will affect ballistics characteristics. Material 32 may then be drawn down and around the liner portion 16 to form a case portion 18 to define chamber 26 as shown in
Explosive 14 may be provided prior to or after shaped charge body 12 is formed and shaped into the desired liner portion 16 and case portion 18 configuration. For example, in some embodiments, explosive 14, such as plastic bonded explosive (PBX), may be injected or extruded into chamber 26. In the embodiment of
Shaped charge body 12 may be formed in various manners associated with the composition of material 32. For example, if shaped charge material is a metal, liner portion 16 may be formed from the sheet of material by stamping, drawing, casting, machining, molding, or by any suitable manufacturing method. However, in other embodiments, the materials may be provided in any suitable form for the particular manufacturing method utilized, such as a liquefied material for casting, a solid block of material for machining, and the like. Further, the material utilized to form the shaped charge may be a metal or a combination of metals, a metal filled resin, a ceramic, glass, barite, refractory material, any other suitable materials, or a combination thereof Barite can also be used when combined with a densifying agent such as ceramics, glass, steel, lead etc or other metal powder.
From the foregoing detailed description of specific embodiments, it should be apparent that apparatuses, systems, and methods of manufacturing shaped charges that are novel have been disclosed. Although specific inventive embodiments have been disclosed herein in some detail, this has been done solely for the purposes of describing various inventive features and aspects, and is not intended to be limiting with respect to the scope of the claims herein. It is contemplated that various substitutions, alterations, and/or modifications, including but not limited to those embodiment variations which may have been suggested herein, may be made to the disclosed embodiments without departing from the spirit and scope of the specification and the claims herein.
