RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63/215,963, filed June 28, 2021.

BACKGROUND

[0002] Generally, when completing a subterranean well for the production of fluids, minerals, or gases from underground reservoirs, several types of tubulars are placed downhole as part of the drilling, exploration, and completions process. These tubulars can include casing, tubing, pipes, liners, and devices conveyed downhole by tubulars of various types. Each well is unique, so combinations of different tubulars may be lowered into a well for a multitude of purposes.

[0003] A subsurface or subterranean well transits one or more formations. The formation is a body of rock or strata that contains one or more compositions. The formation is treated as a continuous body. Within the formation hydrocarbon deposits may exist. Typically, a wellbore will be drilled from a surface location, placing a hole into a formation of interest. Completion equipment will be put into place, including casing, tubing, and other downhole equipment as needed. Perforating the casing and the formation with a perforating gun is a well-known method in the art for accessing hydrocarbon deposits within a formation from a wellbore.

[0004] Explosively perforating the formation using a shaped charge is a widely known method for completing an oil well. A shaped charge is a term of art for a device that when detonated generates a focused output, high energy output, and/or high velocity jet. This is achieved in part by the geometry of the explosive in conjunction with an adjacent liner. Generally, a shaped charge includes a metal case that contains an explosive material with a concave shape, which has a thin metal liner on the inner surface. Many materials are used for the liner; some of the more common metals include brass, copper, tungsten, and lead. When the explosive detonates, the liner metal is compressed into a super-heated, super pressurized jet that can penetrate metal, concrete, and rock. Perforating charges are typically used in groups. These groups of perforating charges are typically held together in an assembly called a perforating gun. Perforating guns come in many styles, such as strip guns, capsule guns, port plug guns, and expendable hollow carrier guns. [0005] Perforating charges are typically detonated by a detonating cord in proximity to a priming hole at the apex of each charge case. Typically, the detonating cord terminates proximate to the ends of the perforating gun. In this arrangement, an initiator at one end of the perforating gun can detonate all the perforating charges in the gun and continue a ballistic transfer to the opposite end of the gun. In this fashion, numerous perforating guns can be connected end to end with a single initiator detonating all of them.

[0006] The detonating cord is typically detonated by an initiator triggered by a firing head. The firing head can be actuated in many ways, including but not limited to electronically, hydraulically, and mechanically.

[0007] Expendable hollow carrier perforating guns are typically manufactured from standard sizes of steel pipe with a box end having intemal/female threads at each end. Pin ended adapters, or subs, having male/external threads are threaded one or both ends of the gun. These subs can connect perforating guns together, connect perforating guns to other tools such as setting tools and collar locators, and connect firing heads to perforating guns. Subs often house electronic, mechanical, or ballistic components used to activate or otherwise control perforating guns and other components.

[0008] Perforating guns typically have a cylindrical gun body and a charge tube or loading tube that holds the perforating charges. The gun body typically is composed of metal and is cylindrical in shape. Charge tubes can be formed as tubes, strips, or chains. The charge tubes will contain cutouts called charge holes to house the shaped charges.

[0009] It is generally preferable to reduce the total length of any tools to be introduced into a wellbore. Among other potential benefits, reduced tool length reduces the length of the lubricator necessary to introduce the tools into a wellbore under pressure. Additionally, reduced tool length is also desirable to accommodate turns in a highly deviated or horizontal well. It is also generally preferable to reduce the tool assembly that must be performed at the well site because the well site is often a harsh environment with numerous distractions and demands on the workers on site. [0010] Electric initiators are commonly used in the oil and gas industry for initiating different energetic devices down hole. Most commonly, 50-ohm resistor initiators are used. Other initiators and electronic switch configurations are common.

[0011] Conventional perforating in vertical wells or unconventional perforating in horizontal wells conveyed by electrical line during which one or more of the perforating guns in the downhole tool string are oriented by either one or more of the following orientating methods: motorized orientation tool, eccentric weight bars and self-orienting charge tube assemblies.

SUMMARY OF EXAMPLE EMBODIMENTS

[0012] An example embodiment may include a shaped charge for perforating a wellbore, comprising an internal liner, an external shell, an explosive material lined disposed within the internal liner and lined with an explosive forming liner, and at least one shock attenuation material disposed between the internal liner and the external liner, wherein the combination of the at least one shock attenuation material provides shock attenuation for the detonation of a shaped charge. [0013] A variation of the example embodiment may include at least one explosive layer disposed between the internal liner and external shell. The explosive layer may fragment the external shell during detonation. The at least one shock attenuation material may be a liquid, gel, solid, gas, granular substance, porous material, a metal, a plastic, and/or a ceramic. The internal liner may be composed of steel. It may include a second external shell layered over the external shell. It may include at least one low density filler material disposed between the internal liner and the external liner.

[0014] An example embodiment may include a shaped charge case for perforating a wellbore, comprising, an internal liner, an external shell, at least one shock attenuation material disposed between the internal liner and the external liner, and at least one low density filler material disposed between the internal liner and the external liner, wherein the combination of the at least one shock attenuation material and at least one low density filler material provides shock attenuation for the detonation of a shaped charge.

[0015] A variation of the example embodiment may include at least one explosive layer disposed between the internal liner and external shell. The explosive layer may fragment the external shell during detonation. The at least one shock attenuation material may be a liquid, gel, solid, gas, granular substance, porous material, a metal, a plastic, and/or a ceramic. The internal liner may be composed of steel. It may include a second external shell layered over the external shell. It may include at least one low density filler material disposed between the internal liner and the external liner. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] For a thorough understanding of the example embodiments, reference is made to the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings in which reference numbers designate like or similar elements throughout the several figures of the drawing. Briefly: FIG. 1 shows an example embodiment of layered shaped charge case.

FIG. 2 shows an example embodiment of layered shaped charge case.

FIG. 3 shows an example embodiment of layered shaped charge case.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS [0017] In the following description, certain terms have been used for brevity, clarity, and examples. No unnecessary limitations are to be implied therefrom and such terms are used for descriptive purposes only and are intended to be broadly construed. The different apparatus, systems and method steps described herein may be used alone or in combination with other apparatus, systems and method steps. It is to be expected that various equivalents, alternatives, and modifications are possible within the scope of the appended claims.

[0018] Terms such as booster may include a small metal tube containing secondary high explosives that are crimped onto the end of detonating cord. The explosive component is designed to provide reliable detonation transfer between perforating guns or other explosive devices, and often serves as an auxiliary explosive charge to ensure detonation. [0019] Detonating cord is a cord containing high-explosive material sheathed in a flexible outer case, which is used to connect the detonator to the main high explosive, such as a shaped charge. This provides an extremely rapid initiation sequence that can be used to fire several shaped charges simultaneously.

[0020] A detonator, initiator, or initiation device may include a device containing primary high- explosive material that is used to initiate an explosive sequence, including one or more shaped charges. Two common types may include electrical detonators and percussion detonators. Detonators may be referred to as initiators. Electrical detonators have a fuse material that bums when high voltage is applied to initiate the primary high explosive. Percussion detonators contain abrasive grit and primary high explosive in a sealed container that is activated by a firing pin. The impact of the firing pin is sufficient to initiate the ballistic sequence that is then transmitted to the detonating cord.

[0021] Initiators may be used to initiate a perforating gun, a cutter, a setting tool, or other downhole energetic device. For example, a cutter is used to cut tubulars with focused energy. A setting tool uses a pyrotechnic to develop gases to perform work in downhole tools. Any downhole device that uses an initiator may be adapted to use the modular initiator assembly disclosed herein. [0022] In the oil well perforating market there is always a need for cheaper shaped charge cases. Shaped Charge cases are typically made using a combination of casting or forging with machine finishing. However even at high quantities these cases are expensive to make.

[0023] There is a need for shock attenuation between charges. Due to limited tool length in wells, as well as completion designs driving for tightly clustered charges with minimal spacing, the need to limit the distance between shaped charges is important. The concern is that the detonation of one shaped charge affects the performance of the next shaped charge. One way to combat this is shock attenuation using different materials, however current industry charge case manufacturing processes do not allow for this to be done. Therefore, an industry need for affective alternative methods to control explosive propagation exists.

[0024] Because the force and directionality of explosive propagation is determined by the bounding materials, shaped charge cases effect the performance of the shape charge overall. Standard production methods allow for the changing of the shape of the charge case, but cannot typically change porosity, add voids, change materials, or other changes that could influence explosive performance. This is a limiting factor since external case geometry is partially driven by gun system design. Being able to control explosive propagation without changing the external case geometry could increase charge performance. In addition, fragmentable charge cases need to limit debris in wells. Also, obtaining different charge performance with a single shaped charge to limit size of selling portfolio is desirable.

[0025] An example embodiment, as shown in FIG. 1, may include a shaped charge 100. The shaped charge case in this example is composed of a steel internal liner 104, a low-density filler material 103, a shock attenuation layers 102, and an external shell 101. The steel internal liner 104 may include a shoulder 105 that overlaps the layered materials such as the low-density filler material 103 and the shock attenuation layers 102. The steel liner 104 may include a radius 106 that can be adjusted to provide different performance characteristics of the shaped charge 100. Typically, a shaped charge 100 will include an explosive 110 with a concave shaped liner 109 that forms a projectile when detonated. The explosive output of the shaped charge 100 is capable of puncturing casing and the wellbore formation. Other example embodiments may include the shaped charge case being composed of the internal liner 104 and the external shell 101 with a void in between. The shaped charge case may be composed of the internal liner 104 and the external shell 101 with or more attenuation layers 102 in between. The shaped charge case may be composed of the internal liner 104 and the external shell 101 with or more layers of filler material 103 in between.

[0026] The case for the shaped charge 100 may be produced by stamping multiple layers of materials or assemble a charge case from multiple pressed layers. The example embodiment of FIG. 1 minimizes shock attenuation using layered materials in a charge case and allow for tight clustering of charge cases. The example embodiment effects and controls explosive propagation without changing charge case geometry. The example embodiment shaped charge case may be manufactured using a method for creating charge cases utilizing stamped materials with a layered charge case attenuated shock. The shaped charge case uses a layered charge case to control explosive propagation and increase charge performance. The manufacturing method of shaped charge case may include obtaining multiple levels of performance with a single shaped charge. The manufacturing method of shaped charge case may increase fragmentation of charge cases. The charge case materials can be either pyrotechnic or high explosive. It can be liquid, gel, solid, gas, or a granular substance. It can be porous, complete voids, or solid materials. It can be metal, plastic, ceramic, or other materials. It can be any geometry, including cylindrical like standard shaped charges or conforming to a non-cylindrical geometry with portions to affect performance. The materials can be assembled by stamping together, laminating together, friction fitted, or interference fitted together. It can be assembled with adhesives such as glue, epoxies, and/or resins. It can be assembled postproduction by the end user. It can be stackable. The layers can be removable. The configuration of the materials can be on a single plane or multiple planes. It can be partially overlapping, fully overlapping, or not overlapping.

[0027] The example embodiment in FIG. 2 may include one or more layers of energetic material 107 located between internal liner 104 and the external shell 101 to affect case fragmentation and combustion. [0028] The example embodiment in FIG. 3 may allow the addition or removal of one or more extra layers of casing 108 to change charge performance in the field.

[0029] The example embodiment can be manufactured for creating an explosive shape charge case using single or multiple stamped materials. The materials can be stamped together or stamped separately and assembled. The stamped materials may be pressed, laminated, glued, or interference fitted together. The thin layers of material allow for the custom design of the case shock attenuation. Materials can also be chosen to maximize attenuation, with the possibility of using porous and non-metallic materials. The example embodiment can be made cheaply and uniformly, because the case may be stamped. The material location and density can be altered without changing the geometry of the charge case because multiple materials can be used. This allows for control of explosive propagation without changing the external geometry of the charge case. Layers of the case can be removed to alter the confining forces on the explosive. These changes will also impact charge performance allowing a single shaped charge to have multiple performance possibilities. Adding a layer of energetic material to the charge case increases fragmentation and reduces size of debris.

[0030] Although the example embodiments have been described in terms of embodiments which are set forth in detail, it should be understood that this is by illustration only and that the example embodiments are not necessarily limited thereto. For example, terms such as upper and lower or top and bottom can be substituted with uphole and downhole, respectfully. Top and bottom could be left and right, respectively. Uphole and downhole could be shown in figures as left and right, respectively, or top and bottom, respectively. Generally downhole tools initially enter the borehole in a vertical orientation, but since some boreholes end up horizontal, the orientation of the tool may change. In that case downhole, lower, or bottom is generally a component in the tool string that enters the borehole before a component referred to as uphole, upper, or top, relatively speaking. The first housing and second housing may be top housing and bottom housing, respectfully. In a gun string such as described herein, the first gun may be the uphole gun or the downhole gun, same for the second gun, and the uphole or downhole references can be swapped as they are merely used to describe the location relationship of the various components. Terms like wellbore, borehole, well, bore, oil well, and other alternatives may be used synonymously. Terms like tool string, tool, perforating gun string, gun string, or downhole tools, and other alternatives may be used synonymously. The alternative embodiments and operating techniques will become apparent to those of ordinary skill in the art in view of the present disclosure. Accordingly, modifications of the example embodiments are contemplated which may be made without departing from the spirit of the claimed example embodiments.