Abstract: A modular propellant assembly for fracturing wells has a propellant charge with a detonating cord extending along its length to ignite the propellant. Each propellant module also has end caps with male and female connectors that enable propellant modules to be connected in an end-to-end relationship to any desired length. These connectors align the ends of the detonating cords in adjacent propellant modules and are sealed with O-rings so that the detonating cords remains dry while submerged at high pressures. This enables the detonating cords to be ignited in series.

Abstract: An apparatus (38) and method for progressively gravel packing an interval of a wellbore (32) is disclosed. The apparatus (38) comprises a sand control screen (52) that is positioned within the wellbore (32) and a tubular member (42) that is disposed within the wellbore (32) forming a first annulus (56) with the sand control screen (52) and a second annulus (58) with the wellbore (32). The tubular member (42) initially prevents fluid communication between the first annulus (56) and the second annulus (58). Once the gravel packing operation begins, however, the tubular member (42) selectively allows fluid communication from the first annulus (56) to the second annulus (58) by progressively establishing fluid communication between the first annulus (56) and the second annulus (58) from a first end of the interval (48) to a second end of the interval (48).

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.

Abstract: A system for unloading fluids from a generally upright tubular member of a wellbore wherein a combustible fuel cell can be placed in the tubular member below the fluid and ignited to generate gasses. The gasses generated by the burning of the fuel cell can be used to force at least a portion of the fluid upward out of the tubular member.

Abstract: A perforating gun assembly for use in a subterranean well incorporates therein an electromagnetic frequency receiver coupled to a motor section which, in turn, is coupled to the mechanically actuatable firing head portion of the perforating gun. The assembly is lowered into a cased wellbore to a subterranean formation location, and a surface-disposed transmitter generates encoded electromagnetic waves through the earth to the receiver. Upon sensing in the received waves a predetermined frequency and embedded firing code, the receiver electrically operates the motor which, in turn, mechanically actuates the firing head to initiate the firing of the perforating gun. While the assembly is illustratively lowered into the wellbore on a tubing structure, a variety of non-tubing structures may be alternatively utilized to lower the gun assembly into the wellbore and operatively support it therein.

Abstract: A method and apparatus for placement of continuous pre-split, gel explosive in an elongated borehole or cavity. An anchor is attached to one end of a selected length of continuous gel explosive. A suitable anchor is a flexible, plastic “pilgrim's hat” with a hole in the narrow, closed end. The size of the anchor depends on the width of the borehole; the flared skirt should be narrow enough to permit insertion of the anchor into the hole but wide enough to resist removal. One end of the explosive charge is pressed through the hole in the anchor. The remainder of the length of explosive is placed inside a tubular member, such as PVC pipe. The loaded pipe then is inserted into the borehole or cavity with the anchor leading. The pipe is used to push the anchor back into the hole to the desired depth. Then, the pipe is withdrawn. The flexible skirt on the anchor engages the sidewall of the borehole and thus resists removal with the pipe.

Abstract: A method and apparatus to protect explosive components used in various tools, such as tools for use in wellbores, includes a component with an adsorptive material. Example tools include perforating gun strings that include shaped charges, detonating cords, and booster explosives. Other tools may include surface tools containing explosive components. The adsorptive material is placed inside a container. A temperature-activated mechanism is used to open the container. The temperature-activated mechanism includes an element formed of a shape memory metal or plural layers with different coefficients of thermal expansion, such as a bi-metallic strip.

Abstract: An apparatus and method for increasing the permeability of a productive oil formation, comprised of desensitized detonating cord with a plurality of steel sleeves thereabout, functioning as pressure compensators, disposed at pre-determined distances along the detonating cord to produce sequential pulse/delays upon ignition of the detonating cord. A high-pressure detonator ignites detonating cord. A protective shield, mounted about the detonator, reduces the explosive force, while preserving the kinetic energy effectuated by the detonator. An external plastic tube, arranged adjacent to the detonating cord, is filled with production enhancing chemicals, which are propelled through clogged perforations and stimulate the surrounding formation, thereby increasing transmissibility of a productive oil formation. A weight and Sample/Junk basket to retrieve materials after the process are mounted to the bottom of the apparatus. A 0.092 diameter support wire serves as the back-bone of the entire apparatus.

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 means 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: A wellsite pumping system, comprising a gas processing system including a source of compressed gas, the source of compressed gas having a low pressure inlet and a high pressure outlet, coil tubing connected to the high pressure outlet of the gas processing system, the coil tubing including a first tubing string connected to the high pressure outlet and a second tubing string running parallel to the first tubing string and having an opening for entry of fluid at a remote end from the high pressure outlet; and a venturi connecting the second tubing string to the first tubing string such that, in operation, passage of gas through the venturi from the first tubing string draws production fluid into the second tubing string. Preferably, the second tubing string is suspended within the first tubing string. The venturi may be formed by a horizontal passageway communicating with a vertical passageway with a restriction.

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 technique includes arranging perforating charges of a perforating gun into groups of adjacent perforating charges. Each perforating charge of each group is aligned in a direction associated with the group. The groups are oriented to form a phasing for the perforating gun.

Abstract: Reinforced borehole plugs useful in the presplitting and blast removal of earth formations, the improvements provided by the invention comprising inflatable devices intended to support stemming, explosives and the like at suspended locations within a borehole to produce desired blast results. The borehole plugs of the invention comprise inflatable sport balls such as are used on playgrounds as toys and which are reinforced according to the invention to maintain inflation within a borehole, a characteristic which playground balls can only inconsistently provide. The borehole plugs of the invention are preferably inflatable through use of valve structures which permit pumping of an inflating fluid into the plugs once the plugs are respectively suspended at desired locations within boreholes prior to filling the boreholes in whole or in part with stemming and/or explosives and the like.

Abstract: A system for lifting water from a gas well uses a propellant charge. The propellant charge with a plunger above is lowered into the well to a depth below the water level in the well. The propellant charge is then ignited to rapidly generate combustion gases that push the plunger upward to lift water from the well.

Abstract: A method and apparatus for enhancing the production of newly developed water wells and existing wells that have suffered a reduction in capacity due to plugging. A gas line directs gas under pressure to a relief valve carried in the production string at a location in the production zone of the well. When the applied pressure reaches the pressure setting of the relief valve, the valve opens to apply air sidewardly in bursts which create shock waves to dislodge built up material from the well screen and the surrounding filter pack and formation fractures. Following each burst, the pressure conditions create a flushing effect which draws water back into the well along with the bacteria and particles that were dislodged. A submersible pump or airlift assembly in the production string then delivers the dislodged materials to the surface.

Abstract: A wellsite inert gas injector, comprising an internal combustion engine, a gas processing system connected to receive low pressure exhaust gas from the internal combustion engine, a compressor within the gas processing system, the compressor having a low pressure inlet for receiving exhaust gases and the compressor having a high pressure outlet; and coil tubing connected to the high pressure outlet of the gas processing system. The gas processing system preferably comprises one or more of a particulate filter, exhaust cooler and exhaust separator in series, and in that order before the compressor.

Abstract: An apparatus and method for removing a frangible rupture disc or other frangible device from a wellbore casing. The casing has a special casing section defining a plurality of holes therethrough. Rupturable glass ceramic discs or inserts are disposed in the holes and retained therein. The glass ceramic discs or inserts are adapted to withstand fluid differential pressure normally present in the wellbore but are rupturable in response to impingement by a pressure wave thereon. The pressure wave is provided by a pressure wave generating device positionable in the casing string adjacent to the holes in the special casing section. The pressure generative device may generate a pressure pulse or an acoustical wave. Methods of perforating a well casing using a pressure pulse or an acoustical wave are also disclosed.

Abstract: A tool containing a solid combustible material is used to provide a pipe-cutting flame and to direct a pipe-cutting flame against a casing or tubular. The nozzles can be configured in any desired array and intensity. In the preferred embodiment, a rectangular window is burned away completely if the nozzles are sufficiently intense or the window is formed in segments if other distributions are used. The device can be anchored by a packer or anchor and can be run in the wellbore on tubing, wireline or electric line. The window can be produced in a single trip. The tool can be removed and a kick-off diverter installed adjacent the window for milling the lateral.

Abstract: A device is disclosed for setting an annular seal in an annular space formed between a large diameter tubular and a small diameter tubular extending into the large diameter tubular. The device comprises a carrier block suitable to be located at a position in the large diameter tubular proximate said annular space, the carrier block being provided with a carrier ring axially movable relative to the carrier block between a first position and a second position and arranged to axially move the annular seal into the annular space upon movement of the carrier ring from the first to the second position thereof, and further comprising an explosive charge arranged to move the carrier ring from the first position to the second position thereof and a detonator for selectively detonating the explosive charge.

Abstract: A method and apparatus to protect explosive components used in various tools, such as tools for use in wellbores, includes a component with an adsorptive material. Example tools include perforating gun strings that include shaped charges, detonating cords, and booster explosives. Other tools may include surface tools containing explosive components. In these tools, a build up of corrosive gases or liquids may occur, which may cause damage to the explosive components. As a result, the structural integrity or reliability and thermal stability may be weakened or reduced. To reduce the amount of build up of corrosive gases or liquids, an adsorptive material is placed inside tools in the proximity of explosive components.

Abstract: An apparatus and method provides an anchoring apparatus for use in a wellbore that comprises a gripping assembly and an actuation assembly. In one arrangement, the actuation assembly includes a motor and a module having at least a compressible element (e.g., a hydraulic module) between the motor and the gripping assembly. Upon activation, the motor actuates the hydraulic module to cause activation of the gripping assembly. In one arrangement, the anchoring apparatus is designed to pass through a tubing or other restriction in the wellbore. When in the retracted state, the gripping assembly of the anchoring apparatus has an outer diameter that is smaller than an inner diameter of the tubing. When in the expanded state, the gripping assembly of the anchoring apparatus has an outer diameter than is substantially the same as the inner diameter of the liner to enable engagement of the gripping assembly against the liner.

Abstract: A procedure for treating the perforations of a well, in particular by intervention of a cable, in order to plug them or consolidate them comprises the successive steps of: (a) arranging, close to the perforation to be treated (50, 54), a dehydration powder chamber (32) that produces a large volume of high pressure gas at a high temperature, as well as a composite powder chamber (40) designed to treat the perforation (50, 54); (b) igniting the dehydration powder; and (c) once the combustion of the dehydration powder is completed, igniting the composite powder so the treatment of the perforation (50, 54) can take place. The invention also relates to a device for implementing this procedure.

Abstract: Apparatus for boring a hole from an inside of a casing outwardly at an angle relative to a longitudinal axis of the casing comprises a drill shoe having a longitudinal axis and being positionable in the casing, the shoe having first and second passageways which converge into a third passageway exiting the shoe, a torsional load transmitting element and a cutting element connecting to one end of the torsional load transmitting element, the torsional load transmitting element and cutting element being positioned in the first passageway during non-use and in the third passageway during use, and a fluid conduit and a nozzle connected to one end of the fluid conduit, the fluid conduit and nozzle being positioned in the second passageway during non-use and in the third passageway during use.

Abstract: A method and apparatus for improving reservoir communication includes, in one arrangement, use of one or more chambers to create an underbalance condition and/or a fluid surge in the wellbore. In another arrangement, a tool string comprises a packer, a circulating valve, and an atmospheric chamber, in which the circulating valve, when open, is adapted to vent a lower wellbore region below the packer when the packer is set, and the atmospheric chamber is capable of being operated to create an underbalance condition below the packer. In yet another arrangement, an apparatus comprises a subsea wellhead equipment including a blow-out preventer, choke line filled with a low density fluid, and a kill line filled with a heavy fluid. The choke line is adapted to be opened to create an underbalance condition in the wellbore.

Abstract: A downhole gas compression system is adapted for location in a bore of a natural gas-producing well (10), the system comprising an axial flow compressor (32) and a gas-filled electric drive motor (30). The motor drives the compressor to compress the produced gas, the compressed gas being directed upwardly through production tubing (20) to surface.

Abstract: Disclosed are new apparatus and methods for transmitting and enhancing the propagation of acoustic signals through a well tubing while providing a vent port. The apparatus and methods can be used to control subsurface well tools without wire or line connections to the surface.

Abstract: A tool activating system includes a multiple control units coupled to activate devices in a tool string positioned in a well. A processor is capable of communicating with the control units to send commands to the control units as well as to retrieve information (such as unique identifiers and status) of the control units. Selective activation of the control units may be performed based on the retrieved information. Further, defective control units or devices may be bypassed or skipped over.

Abstract: An apparatus and method provides an anchor device for use in a wellbore that comprises an actuator assembly responsive to an actuating signal, an operator coupled to the actuator assembly, and an engagement member moveable to a set position by the operator when actuated by the actuator assembly to set the anchor device. The anchor device may be employed in various tool strings, such as a perforating tool string. In one arrangement, the anchor device provides an automated retraction mechanism that is activated after a predetermined delay. In another arrangement, a retract signal may be supplied to activate the retraction mechanism.

Abstract: An explosive pipe cutter assembly (10, 10′) has a housing (20, 20′) which defines at its closed end a hemispherical shaped nose end (22, 22′) and contains a toroidal shaped charge (48) comprised of two half-charges (42). Toroidal shaped charge (48) has a seating surface (31) seated on a support shoulder (50, 50′) adjacent the closed end of the housing (20, 20′), and a trailing end which is engaged by a retaining ring (38) received in the open end (24, 24′) of the housing (20, 20′). Two juxtaposed half-liners (28) provide a liner having an apex (A) which is curved in longitudinal cross section to increase the mass of the metal formed into a penetrating jet by detonation of the shaped charge (48).

Abstract: A system for inducing implosion shock forces on perforation traversing earth formations with fluid pressure where an implosion tool is selected relative to a shut in well pressure and a tubing pressure to have a large and small area piston relationship in a well tool so that at a predetermined tubing pressure the pistons move a sufficient distance to open an implosion valve which permits a sudden release of well fluid pressure into the tubing string and produces an implosion force on the perforations. A pressure gauge on the well tool records tubing pressure and well pressure as a function of time.

Abstract: In a broad aspect, the invention relates to a method and apparatus for downhole safety valve remediation using a measured, controlled, explosion to remove scale and/or other debris from within or around the downhole safety valve or for explosively locking out the safety valve in an open position.

Abstract: A self-firing and self-propelling gas impulse device which includes a housing having a longitudinal axis, a gas inlet port, and one or more gas discharge ports; an inlet chamber, arranged for gas communication with a source of compressed gas via the inlet port and operative to receive compressed gas therefrom; a pressurization chamber arranged for gas communication with the inlet chamber thereby to facilitate a build-up of pressurized gas therein, and arranged for selectable gas communication with the one or more discharge ports; and a piston unit arranged along the longitudinal axis of the housing between the inlet chamber and the pressurization chamber.

Abstract: A brake mechanism for use with a perforating gun to prevent the explosive forces from causing recoil comprising a cylindrical body with openings permitting brake plugs to engage the well casing in response to pressure against an axially moving piston driven by the explosive force of the perforating gun and having a tapered side wall to drive the plugs against the casing. A bias spring disengages the axial piston and a retractive spring withdraws the plugs from engagement.

Abstract: A well, such as a natural gas well, may be treated to increase production of gas by inserting into the tubing string a water soluble carrier containing a well treating chemical adapted to aerate fluids standing in the tubing string. The dissolvable carrier contains a compressed swab adapted, upon dissolution of the carrier, to expand to fill the diameter of the tubing string, and well treating chemicals adapted to aerate the standing fluid in the well above and below the swab. The presence of the aerating fluids in the well lighten the hydrostatic head, permitting a plug of fluid above the swab to be displaced from the well as the swab is urged upward due to pressure exerted on the swab by the formation and by the aerating effect of well treating chemicals released below the swab.

Abstract: A hydrocarbon producing well is treated by first igniting a gas generating charge in the well to clean out perforations communicating between the casing and the formation without creating high permeability channels adjacent the perforations or fracturing the formation in a macroscopic sense. Then, a treatment liquid is injected into the wells by a gas generating propellant charge placed in the production string and then ignited. The propellant charge is designed to produce a minimum horsepower sufficient to push the liquid more-or-less equally through all of the open perforations. The propellant charge is designed to produce a maximum horsepower which is less than what is necessary to fracture the formation. Basically, the combustion rate of the propellant charge is reduced by one of a multiplicity of techniques to produce a long, relatively slow combustion rate.

Abstract: Apparatus and methods are provided for completing a wellbore junction. In one embodiment described herein, a lateral wellbore junction is sealed utilizing an apparatus assembled within the well. The apparatus may include multiple housings which are engaged with each other to form a sealed assembly with flow passages extending into the lateral wellbore, and upper and lower portions of a parent wellbore. Associated sealing devices and flexible couplings are also provided.

Abstract: An apparatus for opening perforations in a casing string. The casing string has a special casing section defining a plurality of holes therethrough. Rupturable ceramic discs or inserts are disposed in said holes and retained therein. The ceramic discs or inserts are adapted to withstand the fluid differential pressures normally present in the wellbore but are rupturable in response to impact by a mild explosive charge. The explosive charge is provided by detonating a length of det-cord disposed in the casing string adjacent to the holes in the special casing section. A method of perforating using this apparatus is also disclosed.

Abstract: A method for stimulating a subterranean formation which is penetrated by a well bore having casing positioned therein so as to establish fluid communication between the formation and the well bore. Propellant is secured to the outer surface of a carrier having a plurality of apertures formed therein. Detonating cord is positioned within said carrier and when ignited causes the propellant to ignite initially at each aperture. In this manner, the propellant is caused to burn in controlled, uniform manner. Upon burning, the propellant generates gases which clean perforations previously formed through the casing into the formation and which extend fluid communication between the formation and the well bore.

Abstract: An apparatus and method for severing a tubular, such as a drill string, which is stuck within a subterranean well bore. A volume of liquid explosive is positioned within a housing and initially restrained against movement therein. The housing is lowered within the tubular and positioned at a location where the tubular is to be severed. The volume of liquid explosive is then moved into closer proximity to the tubular and detonated thereby severing the tubular. A portion of the tubular is then removed from the well bore.

Abstract: A wellbore completion system utilizes casing conveyed devices to establish a fluid communication path between a downhole formation and the casing string. Extendible pistons are mounted in the wall of the casing pipe string and are extended toward contact with the downhole formation after the casing is set. An explosive device is mounted in the pistons and includes a detonator and a shaped charge. The detonator is housed in a plug threaded into one end of the piston. The shaped charge is housed in a canister conveniently inserted into the other end of the piston. The explosives included in the system may thus be conveniently assembled at the well site. Explosive in the pistons are activated by a separately conveyed activation system which produces a pressure wave to detonate the explosives and establish fluid communication between the casing and formation.

Abstract: A method of delaying detonation of an explosive device within a subterranean well is provided which is convenient, economical and efficient in its use. In addition, the safety of such operations is enhanced by the construction of a firing head used in the method and engaged with the explosive device in the well. In one described embodiment, the firing head includes a piston reciprocably received in a fluid chamber, and an orifice for metering fluid from the chamber. When the firing head is engaged with the explosive device, weight is applied to the piston, thereby forcing fluid from the chamber through the orifice and producing a time delay. After the piston has traveled a predetermined distance relative to the chamber, its further displacement is relatively unrestricted and the weight drives the piston downwardly to cause detonation of the explosive device.

Abstract: An improved emergency release tool is provided to releasably connect a coiled tubing to one or more downhole tools. The emergency release tool broadly includes a releasable slip for holding a coiled tubing, the releasable slip being secured to a first end of a slip case, the slip case being disposed within a slip housing and a lower housing, the slip housing being movable from a locked position to a released position; a piston slidably disposed about the slip case and being moveable from a locked position to a released position; a first end of the lower housing being releasably connected to a second end of the slip housing when the slip housing is in its locked position; and, a remotely activated means for moving the piston and the slip housing from their locked positions to their released positions to disengage the releasable slip from the coiled tubing and enable the coiled tubing to be removed from the tool.

Abstract: A method of severing a downhole pipe for forming a region in the well borehole devoid of downhole pipe for enhancing the performance of a perforating gun comprising the steps of: severing, at an angle, by a first cutting tool the downhole pipe to form an upper downhole pipe portion and a lower downhole pipe portion to form a sloped cut line; releasing potential energy stored in the upper downhole pipe portion and the lower downhole pipe portion; inserting a plug to seal an up-hole portion of the upper downhole pipe portion; cutting the up-hole portion via a second cutting tool above the plug into an upper piece and a lower piece; and, jettisoning the lower piece downwardly wherein as the lower piece jettisons downwardly the region in the well borehole devoid of downhole pipe is formed. Such method eliminates the need for: removing a well head; a crane or rig for raising a cut up-hole pipe; and, a pump for controlling the pressure of the well.

Abstract: A self-contained tool incorporates an electronic system for significantly reducing the number of batteries required to detonate an explosive downhole, making the tool short enough for transport by helicopter, rather than by boat, to an offshore well. This shortness is further beneficial for negotiating tight-radius bends in deviated wells. Safety is improved by a shear pin holding a pressure-activated switch in an open position until sufficient pressure shears the shear pin. Control from the surface is provided in applications where fluid pressure is controlled at the surface and raised to shear the shear pin. Longer run-in time is better accommodated by the combination of the electronic system and the shear pin.

Abstract: A method and apparatus for diffusing a treating agent into a medium, a method and apparatus for injecting a liquid into a medium, and a method of remedying soil. The method of diffusing a treating agent into a medium, comprises a step in which a solidified treating agent is scattered and diffused by the pressure of a gas resulting from a gas-generating agent.

Abstract: Apparatus and associated methods of using provide access to a portion of a parent wellbore that has been separated from the remainder of the parent wellbore by a lateral wellbore liner. In a preferred embodiment, an apparatus has a cutting device, which may be a torch, a housing containing the cutting device, and an anchoring structure to fix the axial, radial, and rotational position of the apparatus relative to the liner. A firing head may be utilized to activate the cutting device.

Abstract: Apparatus and associated methods of using the apparatus provide ease forming an opening from a first wellbore to a second wellbore, the first wellbore having a portion thereof which intersects the second wellbore. In a preferred embodiment, an apparatus has a cutting device disposed within a housing and a series of spaced apart nozzles directed radially outward from the housing. In another preferred embodiment, the apparatus is axially, rotationally, and radially alignable relative to the liner of the first wellbore. The cutting device is connected to the nozzles. The nozzles direct a discharge from the cutting device radially outward to cut into the tubular structure.

Abstract: A method and device for stimulating and completing a drilled wellbore in a productive formation. The device comprises a pipe having a plurality of weakened portions and containing a propellant material. When the propellant is ignited it produces rapidly expanding gaseous combustion products which puncture the weakened portions of the pipe. The expanding gas fractures the surrounding formation thereby stimulating the formation to production. The pipe remains in the wellbore and is used for collecting oil and gas from the formation.

Abstract: An explosive displacing bore hole tube is formed by an elongated tubular member having opposite ends thereof closed, as by caps, to enclose a nonexplosive material within the tube. The nonexplosive material is preferably nonpressurized air; bore hole cuttings or other material may be added for ballast. Alternatively, the tube may be completely filled with such cuttings. The explosive displacing tube is positioned within a bore hole along with a bulk flowable explosive to reduce the volume of explosive at a selected location or locations along the bore hole to thereby reduce the blast intensity at such a location or locations when the explosive is detonated. A tube filling apparatus is provided for simultaneously placing ballast in a plurality of the tubes.

Abstract: A fluid actuated detonating device is shown being used to activate explosive devices in a borehole. The detonating device has an explosive detonation charge arranged in a housing wherein a rupture disc in the wall of the housing separates the explosive charge from a fluid environment so that when pressure in the fluid environment is raised to a sufficient level the rupture disc fails and communicates a sudden pressure wave to the explosive to detonate the explosive.