Abstract: A method for assembling a stackable perforating gun system inside a well bore is provided that includes attaching a first gun section of the stackable perforating gun system to a tracking assembly, and transporting the first gun section within the well bore using the tracking assembly. The method also includes disengaging the first gun section from the tracking assembly; retrieving the tracking assembly to the surface; attaching a second gun section of the stackable perforating gun system to the tracking assembly; transporting the second gun section within the well bore using the tracking assembly; and coupling the second gun section with the first gun section using the tracking assembly.

Abstract: This device relates to the fields of mining, specifically oil and gas industry, hydro-geological, geological engineering and water supply industries and is intended for cutting slot-shaped seats in well side zones of producing formation by hydro-abrasive blast. The determined task is solved by introducing essential changes into the known device for construction of cutting slot-shaped seats from the well wall inside the rock consisting of the hydro-abrasive jet generator connected with the perforator through the pump-and-compressor tubing string; the perforator is put into the casing pipe and has two diametrical nozzles which are directed at the well wall; there is a ball valve at the perforator end, as well as devices for adjustable partial unloading of PCS, PCS weight measuring device, abrasive jet pressure measuring device and the sealer for sealing of wellhead.

Abstract: A method of manufacturing an expandable slotted tube fabricated from at least one tubular element and at least two annular elements connected to the opposite ends of the tubular element by means of butt joints wherein axially extending slots are formed at a uniform angular spacing around the periphery of the tube and in longitudinally overlapping relation characterized by cutting said annular elements in a pattern of overlapping positionally fixed slots in accordance with invariable parameters which are pre-determined relative to the dimensions of said annular elements and cutting in said tubular element a pattern of slots that is variable in accordance with measured parameters of the tube so as to achieve the required overlap between said positionally fixed and variable slots. A machine for carrying out the method is also described.

Abstract: Cutting apparatus having a ram axis gear tube (32) equipped with internal threads engageable with external threads (48) of a main shaft (42). A tool can be fixed to the main shaft (42). The external threads (48) of the main shaft (42) are formed on external splines (44). A main shaft rotation gear (46) has internal splines (41) mating with the external splines (44) of the main shaft (42). Rotation of the ram axis gear tube 32 thus causes the main shaft (42) to move axially via the internal and external threads. Rotation of the main shaft rotation gear (46) causes rotation of the main shaft (42). The tool fixed to the main shaft (42) can thus undergo axial and rotational movements. A motor (74) can be coupled to main shaft (42) and a motor shaft (63) extended through the ram axis gear tube (32) and the main shaft (42). The motor shaft (63) can drive a linear gear (68) of a cross slide assembly (24) and thus radially move a tool fixed to the cross slide assembly (24).

Abstract: A surge chamber assembly (70) for use in a wellbore includes a housing (80) having one or more openings (112), a surge chamber (100) and a combustion chamber (98). The openings (112) provide fluid communication between the exterior (82) of the housing (80) and the surge chamber (100). A sleeve (114) is slidably positioned within the housing (80) and has a first position wherein fluid communication through the openings (112) is prevented and a second position wherein fluid communication through the openings (112) is allowed. A combustible element (124) is positioned in the combustion chamber (98) such that combusting the combustible element (124) generates pressure in the combustion chamber (98) that actuates the sleeve (114) from the first position to the second position.

Abstract: A connection system to be used in conjunction with a perforating gun comprising a top sub formed to receive one end of a gun body of a perforating gun, a circumferential groove disposed on the outer surface of the gun body, and a collet secured to the top sub. The collet has at least one finger that engages the groove. Engaging the groove with the at least one finger of the collect connects the gun body to the top sub. A cover sleeve is included that retains the finger in connective engagement with the groove.

Abstract: A pipe breaking assembly is shown with a modular design that allows a user to more economically purchase a single base unit that is adaptable using a number of elements. Combinations of elements such as blade portions and expander cones, etc. allow the modular assembly to be tailored to a variety of job conditions. A pipe breaking assembly is shown that includes a particular configuration where a blade portion is located in front of a shortened expander cone. The shortened expander cone provides a lower contact area that in turn reduces friction.

Abstract: A connection system to be used in conjunction with a perforating gun comprising a top sub formed to receive one end of a gun body of a perforating gun, a circumferential groove disposed on the outer surface of the gun body, and a collet secured to the top sub. The collet has at least one finger that engages the groove. Engaging the groove with the at least one finger of the collect connects the gun body to the top sub. A cover sleeve is included that retains the finger in connective engagement with the groove.

Abstract: The weight of a shaped charge carrier is predetermined as a buoyancy control parameter for perforating guns. Each charge carrier comprises a co-axial assembly of inner and outer carrier units. Both carrier units may be fabricated from low density metals or composite materials comprising high strength fibers in a polymer matrix. The outer carrier wall thickness may be a weight control parameter. Shaped charge units having no independent casement are formed into sockets within a light-weight inner carrier unit. Alternatively, the shaped charge units may be formed within light-weight material cases and seated within sockets in the light-weight inner carrier unit. Materials and dimensions are selected to substantially achieve the desired carrier buoyancy in the specific well fluid whereby a perforating gun assembled from a plurality of the carriers may be substantially floated into a completion position and allowed to settle along the floor or ceiling of the wellbore as predetermined by the perforation direction.

Abstract: The loading tube comprises cups forming cup cavities for enclosing an explosive charge within each of the cups. The loading tube has ridges and valleys providing longitudinal and lateral strength to the loading tube. The loading tube is constructed of a formed material such as paper pulp, high-density polystyrene, plastic or sheet metal.

Abstract: A safety cable cutter used for cutting a cable used in servicing an oil and gas well. A centrifugal arm roller and a guide roller are mounted on top of a frame. The cable is received on the rollers as the cable is lowered down a well bore. Mounted on ends of the centrifugal arm roller is a centrifugal arm attached to an arm coil spring. The coil spring holds the centrifugal arm next to the end of the roller. Opposite ends of a clamp attached to a cutter bar are slidably received in a pair of cutter bar guides. When the centrifugal arm roller exceeds a certain speed indicating a free fall of the cable, the bias force of the arm coil springs is overcome and the arms move outwardly. Contact ends of the arms engage the opposite ends of the clamp. The clamp and cutter bar are then moved outwardly and the cutter bar cuts the cable.

Abstract: A method and apparatus for reducing debris in a perforation in a wellbore extending from the wellbore into a subterranean formations is provided. A housing is positioned in the wellbore, and an arm is extended therefrom. One or more plugs are positionable in the perforation via the arm. The plug is adapted to block debris from formation fluid flowing into the housing via the perforation whereby the contamination in the formation fluid is reduced. The plug may be a filter positionable in the perforation, or a bit activated to dislodge debris.

Abstract: A system for perforating a well includes a plurality of perforating guns suspended in the well from the wireline or coiled tubing. A downhole electronic command circuit is provided for firing each of the guns in response to a command signal from the surface. A conductor cable, which may be the wireline, extends from the surface to the downhole command circuit, such that command signals fire the guns in a selected order.

Abstract: A shaped charge is formed having a pressed polymer pellet positioned between the explosive charge and the metal liner. The shock wave resulting from detonation of the explosive passes through the polymer to the liner. The collapse of the liner results in the formations of a jet—piercing the casing. The high-pressure gaseous by-products of the explosive force (inject) the polymer in the perforation “tunnel”. This shockwave will also start the decomposition of the polymer. The polymer will continue to decompose during its injection into the tunnel. As it is being injected into the perforation tunnel, the residue heat generated by the explosive combined with the shear and induced plastic flow, the polymer will ignite and burn. The burn time will be an order of magnitude greater than the explosive; the pressure generated by the polymer will be an order of magnitude less than the explosive.

Abstract: A method for the cutting of underwater structures below the level of the sea bottom on which they are installed, comprises determining an ideal plane of cutting, having considered the characteristic features of the structure i.e. its morphology and its positioning on the bottom, the shape and consistency of the bottom itself, and the depth below the level of the bottom at which the cut must be effected; positioning and anchoring of a cutter in proximity of the cutting area; obtainment of at least one perforation or boring in proximity of the structure through the bottom at least up to the predetermined level for the cutting of the structure, along a direction parallel to the cutting direction and preferably lying on the cutting plane; and introduction of the cutter inside the perforation or boring and cutting of the structure. An apparatus for carrying out the method is also provided.

Abstract: A method and apparatus for removing a string of casing from a well bore. The method and apparatus include a plurality of drill bits substantially aligned with each other for drilling a plurality of holes in the string of casing. The plurality of holes can be used to lift the string in casing from the well bore via a series of incremental casing sections.

Abstract: A drain line re-perforator device for punching holes in clogged drain pipe sections in a sewage disposal system is provided. The re-perforator device includes an outer cylindrically-shaped housing member and a dual-actuating ram assembly disposed concentrically within the outer housing member. Three equally spaced-apart angled bracket members are mounted hingedly on the peripheral surface of the outer housing member and includes a punch bit positioned for outward radial movement. The ram assembly is formed of a cylinder and a piston rod. The piston rod is moved in a reciprocal motion from a retracted position to a an extended position so as to cause the angled bracket members to pivot outwardly and the punch bits to move outward radially for punching holes in the clogged drain pipe sections.

Abstract: The present invention provides for a perforating gun having stackable sections that latch, enabling the gun string to carry both compressive and tensile loads. This allows for the downhole assembly of guns of any desired length, and for the entire gun string to be removed after firing.

Abstract: A process and assembly for completing and providing sand control in a subterranean well and/or fracturing and preventing proppant flowback in a subterranean formation in a single trip. One or more perforating gun assemblies are juxtaposed and secured to one or more screen assemblies. Once positioned in a well adjacent a subterranean formation of interest, the explosive charges in each perforating gun assembly are detonated so as to penetrate the well and formation thereby initiating fracturing. The penetrations and the annulus defined between the well and screen assembly are then packed with gravel. Well fluid may be pressurized to in excess of the formation pressure prior to detonation of the explosive charges so as to enhance formation fracturing.

Abstract: A pipe severing tool is arranged to align a plurality of high explosive pellets along a unitizing support structure whereby all explosive pellets are inserted within or extracted from a tubular housing as a singular unit. Electrically initiated exploding wire detonators (EBW) are positioned at opposite ends of the tubular housing for simultaneous detonation by a capacitive firing device. The housing assembly includes a detachable bottom nose that permits the tool to be armed and disarmed without disconnecting the detonation circuitry. Because the tool is not sensitive to stray electrical fields, it may be transported, loaded and unloaded with the EBW detonators in place and connected.

Abstract: A method of determining the extent of detonation of a Well Perforating Gun is disclosed. The Perforating Gun is positioned in a borehole and the detonation is initiated at one point on the essentially curvilinear array of explosive charges. Seismic waves emanate from the series of explosions, propagate away from the Perforating Gun and are detected at a distance away from the Perforating Gun using seismic receivers consisting of single or arrayed transducers of conventional design. The seismic receivers may be placed at or near the earth's surface and/or in one or more boreholes. The recorded seismic waves are processed and analyzed, and may be decomposed through a novel inversion process. The combined results are further analyzed to determine the extent of detonation including whether the gun fired or not, and if there was a misfire or partial misfire, the quantitative extent of the detonation.

Abstract: An electro-mechanical wireline assembly as shown for anchoring a wireline tool string in place during a wellbore under balanced well conditions. The assembly includes an upper connection for connection to the wireline leading to the well surface and a lower connector for engaging a wireline tool. An outer mandrel is attached to the lower connector. An inner mandrel is carried at least partly within the outer mandrel and is capable of axial movement within the outer mandrel. A slip gripping assembly is carried on the outer mandrel and includes slips which are normally biased radially inward but which can be moved radially outward for engaging a surrounding wellbore and holding the wireline tool string in place. An electric motor assembly is carried on the wireline assembly between the upper and lower connectors.

Abstract: A section mill for casings used in oil wells to cut predetermined portions for repair purposes. An elongated cylindrical assembly is inserted through the casing and it includes at least two spaced apart apertures with one blade member pivotally mounted within each aperture. First and second coaxially disposed tubular shaft assemblies with teethed portions to coact with the blades to selectively move them between two extreme position upon the application of a pressurized fluid. The fluid needs to overcome the spring biased applied to the shaft assemblies. The first set of blades is stopped and slidably rotates in contact with the internal surface of the casing. The second set cuts through the casing with one end and sections the casing with the other end. After wearing off, the first set of blades continues the sectioning work.

Abstract: A method for facilitating horizontal drilling by positioning in a well casing a shoe defining a passageway extending from an upper opening in the shoe through the shoe to a side opening in the shoe. A rod is connected, through at least one block and pin assembly operative as a universal joint, to a casing mill end, and inserted into the well casing and through the passageway in the shoe until the casing mill end substantially abuts the well casing. The rod and casing mill end are then rotated until the casing mill end substantially forms a perforation in the well casing. The rod and casing mill end are then withdrawn from the well casing, and a nozzle attached to the end of a flexible hose is extended through the passageway to the perforation. Fluid is then ejected from the nozzle and impinges and erodes subterranean formation material.

Abstract: A coalbed methane borehole pipe liner perforation system comprises a plastic pipe punch that slips down inside a coalbed methane production borehole lined with a non-perforated plastic pipe. A ground-penetrating radar is used inside the plastic-pipe lined borehole to determine which sections of the pipe are in contact with groundwater. The punch is then operated along the length of the plastic-pipe lined borehole to perforate it for methane-gas collection wherever such groundwater is not present. A radar survey to determine groundwater contact can be made simultaneously in combination with the punching of liner pipe perforations, or earlier in a separate operation.

Abstract: A perforating gun assembly useful in hydrocarbon well completion. The gun is assembled in a carrier made from straight walled tubing as a primary structural member with complementary male and female threads cut into opposite ends so that gun assemblies may be directly connected together. The male coupling includes a reinforcing sleeve threaded into an internal thread. An alignment pin is positioned in the carrier extending through the reinforcing ring and into the interior of the carrier. A charge assembly includes a charge holder tube with upper and lower alignment fixtures. The lower alignment fixture includes an alignment slot for mating with the alignment pin and a shoulder for supporting the charge assembly on the sleeve. The upper alignment fixture has an alignment pin for mating with an alignment slot in the carrier. A retainer ring may be threaded into the upper female threads to prevent removal of the charge assembly from the carrier.

Abstract: An apparatus and method for use in severing casing as it is pulled from a wellbore. An apparatus is first provided, comprising a clamping assembly, a drilling assembly and a cutting assembly. In one aspect, the apparatus is disposed at the end of a telescopic arm, with the components being remotely operated by personnel using a control panel. The apparatus can be positioned adjacent casing and clamped thereto. Thereafter, the apparatus can drill a hole completely through the casing for the insertion of a retention pin. The apparatus can then severe the casing into manageable lengths to facilitate disposal, such as during a plugging and abandonment procedure.

Abstract: An instrumented perforating gun and associated methods. One aspect provides a recess for placement of instruments on the perforating gun. Another aspect provides methods for perforating and completing a well in a single trip. The present invention also provides an instrumented intergun housing. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: Apparatus and associated methods of using the apparatus are disclosed for performing cuts in a subterranean well. The apparatus utilizes linear shaped charges arranged in an endless pattern which are used to cut a pattern in a downhole structure. The charges are discharged to perform the cutting operation.

Abstract: The apparatus is used for cutting an opening through the wall of a conduit located in a borehole traversing the subsurface formations. The apparatus includes a body adapted to be lowered into the conduit to a desired level. The body is formed by a cylindrical wall defining an elongated chamber having a combustible charge receiving portion and an ignition system portion located close to the combustible charge receiving portion. A plurality of spaced apart apertures are formed through the wall defining a given pattern which may be at least one elongated row of apertures generally parallel with the axis of the cylindrical wall or a line which encloses a given configuration on one side of the axis.

Abstract: The present invention discloses and claims a system for forming an opening, or window, in a downhole tubular for the subsequent formation of a lateral wellbore. In the system of the present invention, an apparatus is run into the parent wellbore which includes at least a tubular having a drill bit, a diverter such as a whipstock releasably connected to the drill bit, an anchoring device such as a packer, and a milling device. This apparatus allows for the milling of a window in the parent wellbore, and the drilling of a lateral wellbore through that window, in a single trip.

Abstract: A perforator apparatus for repeated punching of holes at a multiple of selected locations in tubing of a well bore. The apparatus is activated for repeated punching operations by a fluid control valve mechanism that controls opposed directional movement of a piston connected to a punch of the perforator apparatus.

Abstract: An apparatus and method is provided to reduce interference resulting from activation of explosive devices. To reduce interference, one or more shock impeding elements are placed proximal one or more explosives to impede propagation of shock caused by detonation of the explosives. The shock impeding elements include a porous material, such as a porous liquid or solid.

Abstract: An apparatus is provided which is adapted to be located in a conduit to be severed. The apparatus includes an upper ignition device, combustible material and a lower nozzle with a diverter. In operation the ignition device is actuated to ignite the combustible material to form a flame of hot gases for passage through apertures of the nozzle to the diverter which directs the hot gases radially outward and against the conduit to be severed. A uniform mixing cavity is provided above the nozzle in the flow path of the flame to the nozzle for mixing the hot gases prior to passages through the nozzle. A lower cavity is provided for the hot gases flowing out of the nozzle for pressurizing the hot gases at the outlet of the apparatus.

Abstract: A perforating device has a carrier strip (e.g., a linear strip) on which are mounted capsule charges arranged in a desired pattern. The pattern can be a phased pattern, such as a spiral pattern, a triphase pattern, and so forth. Alternatively, the pattern is a 0°- or 180°-phased pattern for performing oriented perforating, with the capsule charges shooting in opposite directions with respect to a desired plane in the formation of the wellbore. One or more brackets can be used to mount the capsule charges to the strip. In one arrangement, the bracket has plural support rings to connect to the capsule charges. In another arrangement, multiple brackets each holding one or more capsule charges may be employed. In yet another arrangement, a tube containing the capsule charges in a phased arrangement can be used. In a further arrangement, instead of using brackets, threaded openings are provided in the carrier strip in which capsule charges can be threadably connected to provide the desired phased pattern.

Abstract: A coalbed methane borehole pipe liner perforation system comprises a plastic pipe punch that slips down inside a coalbed methane production borehole lined with a non-perforated plastic pipe. A ground-penetrating radar is used inside the plastic-pipe lined borehole to determine which sections of the pipe are in contact with groundwater. The punch is then operated along the length of the plastic-pipe lined borehole to perforate it for methane-gas collection wherever such groundwater is not present. A radar survey to determine groundwater contact can be made simultaneously in combination with the punching of liner pipe perforations, or earlier in a separate operation.

Abstract: Method and apparatus are presented for perforating a subterranean formation so as to establish fluid communication between the formation and a wellbore, the wellbore having casing cemented therein, the casing having a cement sheath therearound. The casing is perforated with a mechanical perforator and thereafter a propellant material is ignited within the casing thereby perforating the cement sheath. The formation may thereafter be stimulated with an acid stimulator. The mechanical perforator may include use of a toothed wheel, or a needle-punch perforator. The propellant may be deployed in a sleeve and may comprise an abrasive material.

Abstract: A shaped charge perforating apparatus (50) for perforating a subterranean well is disclosed. The shaped charge perforating apparatus (50) comprises a support member (62) having a plurality of shaped charge mounting locations each having shaped charge (56) positioned therein. Each of the shaped charges (56) has an initiation end and a discharge end. The initiation end of each shaped charge (56) is coupled to a detonator cord (70) The shaped charges (56) are enclosed in a carrier (52) having a plurality of recesses (54) spaced on an exterior surface thereof and having contoured bottom surfaces (80). Each of the recesses (54) is longitudinally and radially aligned with the discharge end of one of the shaped charges (56).

Abstract: A method of slitting a flexible conduit in an underground bore, the conduit having entry and exit ends thereof exposed for access, includes: (1) fitting a retainer to flexible underground conduit adjacent to the entry end thereof, the retainer securing the flexible conduit to limit longitudinal movement thereof relative to the bore, (2) passing pulling means through the flexible conduit; (3) connecting the pulling means to a pipe slitter, and (4) pulling the pipe slitter through the retainer and flexible conduit to slit the conduit, the retainer holding the flexible conduit taut as the slitter passes through the conduit. In one embodiment, the retainer is a shoring clamp assembly including a pair of ring clamps that are secured onto a split end of the flexible conduit and transfer the longitudinal forces applied to the conduit during the slitting operation to an adjacent structure such as a pit wall, thereby holding the conduit taut during the slitting operation.

Abstract: The invention discloses methods of, as well as apparatus and systems for, perforating and treating multiple intervals of one or more subterranean formations intersected by a wellbore by deploying a bottom-hole assembly (“BHA”) having a perforating device and a sealing mechanism within said wellbore. In one embodiment, the perforating device has no washing fluid flow passage provided therethrough. In another embodiment, an erosive jet device is used to perforate at least one interval of said one or more subterranean formations. In yet another embodiment, the BHA has at least one pressure equalization means that establishes pressure communication between the portions of the wellbore above and below the sealing mechanism. In another embodiment, the BHA comprises a perforating device and a sealing mechanism, wherein the perforating device is positioned below the sealing mechanism.

Abstract: A method and apparatus is described for increasing hydrocarbon production from a production well by determining a bedding plane (permeability anisotropy) of a hydrocarbon bearing formation and using a perforating tool to form in the formation holes having an essentially elliptical or elongated cross-section with the longest axis of said elliptical or elongated cross-section oriented perpendicular to said bedding plane (or in direction of the lowest permeability).

Abstract: An apparatus for longitudinal splitting, in particular longitudinal slitting, of pipes laid underground and for the simultaneous trenchless pulling-in of a new pipeline comprises a carriage in the form of a frame, in which a cutting wheel for cutting open the pipe wall and a support roller, which serves as an abutment and is supported on the pipe wall, are arranged above one another. The carriage or frame has a base which engages in a form-fitting manner in a frame-like window of a pull and/or push linkage.

Abstract: The present Invention relates to novel devices and methods to minimize the production of sand in subterranean environments; in particular, in poorly consolidated formations, sand is often co-produced along with the desired fluid (e.g., oil); sand production is undesirable, hence in the present Invention, elliptically shaped perforations of a particular orientation are created in the casing (or directly into the formation in the case of an uncased wellbore) that lines wellbore drilled through the formation, to improve near-wellbore stability of the formation, hence minimizing sand intrusion.

Abstract: A perforating gun (10, 210, 310, 410) is provided for retaining a plurality of explosive charges (16, 16′) in an angular phased array with the discharge ends (16a, 16a′) of each succeeding explosive charge (16, 16′) disposed at a selected angular orientation relative to the other explosive charges (16, 16′) as determined by the configuration of an undulating path defined by support wires (14, 14′) or wire pairs (19a, 19b). The perforating gun (10, 210, 310, 410) comprises a plurality of support wires (14, 14′) disposed about a common longitudinal axis (L—L) and extending in an undulating path so as to define a wire carrier or cage in which the explosive charges (16, 16′) are retained by securing the discharge ends (16a), or the initiation ends (16b), or both, to support wires (14, 14).

Abstract: To separate relatively long upright pipes (13) which have a relatively large diameter, the lower end thereof being fixed in the ground, in particular of support legs (3) of an off-shore oil bore or conveying platform (100), a cutting unit is lowered down into the pipe (13) to a separation point. The cutting unit (40) acts gradually from the inside across the periphery to the internal periphery of the pipe (13) and cuts through the pipe (13) by removing metal. A bore tool head (60) is mounted upstream of the cutting unit (40), viewed from the lowering position, and is used to bore out material in the pipe such as ocean bed or concrete.

Abstract: An apparatus for drilling holes in the steel casing of an a oil or gas well, and drilling into the surrounding earth, includes a number of components controlled by hydraulic fluid. A first hydraulic motor drives a steel milling assembly and a second hydraulic motor drives a rock drilling assembly. All assemblies are supported in a housing that is conveyed by conventional jointed pipe or coiled tubing down the well casing. Control components cause a carriage carrying the milling assembly to be indexed up a predetermined distance relative to the well casing, and then extend a mill bit gradually into contact with the well casing while being rotated by a hydraulic motor. After the mill bit completes a hole through the well casing, the hydraulic components retract the mill bit and index the carriage back down to its starting position to align a rock drilling bit with the hole that was just drilled in the casing.

Abstract: A perforating gun for use in underground wells where the gun includes a forward guiding element and a rearward conveyancing element. These two elements are interconnected by way of a series of bow springs. In the preferred embodiment, the springs are spirally configured around the central axis of the gun. The spring function in applying pressure to the internal surface of the well shaft and in centering the gun. Additionally, the springs serve in removably carrying a series of explosive charges. The spiral configuration allows perforations to be created in a 360 degree pattern around the central axis of the gun.