What is presented is a combustible pellet for creating heated gas. The combustible pellet is insertable into a cutting apparatus or a high power igniter or both. The combustible pellet is compacted to be resistant to mechanical damage and is resistant to unintentional ignition. The combustible pellet is ignitable without a loose powdered form of combustible material when the combustible pellet is in the cutting apparatus or the high power igniter.

A technique facilitates analysis of hydraulic fractures. A plurality of explosive pellets is constructed for delivery into fracture or fractures of a subterranean formation. Each explosive pellet comprises an explosive material combined with an initiating member working in cooperation with a friction sensitive pyrotechnic mixture. Crushing or otherwise actuating the initiating member initiates the friction sensitive pyrotechnic mixture which, in turn, ignites the explosive material to produce explosive signals. The explosive signals may be monitored to obtain data related to the fracture or fractures.

A technique facilitates analysis of hydraulic fractures. A plurality of explosive pellets is constructed for delivery into fracture or fractures of a subterranean formation. Each explosive pellet comprises an explosive material combined with an initiating member working in cooperation with a friction sensitive pyrotechnic mixture. Crushing or otherwise actuating the initiating member initiates the friction sensitive pyrotechnic mixture which, in turn, ignites the explosive material to produce explosive signals. The explosive signals may be monitored to obtain data related to the fracture or fractures.

What is presented is a high power igniter comprising an igniter housing adapted to be positioned in a conduit. The igniter housing comprises a containment sub and a nozzle sub that releasably secure to each other. A high wattage heater located in the igniter housing comprises a combustible pellet insertable into the igniter housing for creating a flow of heated gas when the combustible pellet is ignited with a pellet igniting device while the high power igniter is in use. The high power igniter is free from a loose powdered form of combustible material when the combustible pellet is in the igniter housing. The nozzle sub directs the flow of heated gas in the system.

What is presented is a high power igniter comprising an igniter housing adapted to be positioned in a conduit. The igniter housing comprises a containment sub and a nozzle sub that releasably secure to each other. A high wattage heater located in the igniter housing comprises a combustible pellet insertable into the igniter housing for creating a flow of heated gas when the combustible pellet is ignited with a pellet igniting device while the high power igniter is in use. The high power igniter is free from a loose powdered form of combustible material when the combustible pellet is in the igniter housing. The nozzle sub directs the flow of heated gas in the system.

Downhole stimulation tools include a housing and at least one propellant structure within the housing comprising at least one propellant grain of a formulation, at least another propellant grain of a formulation different from the formulation of the at least one propellant grain longitudinally adjacent the at least one propellant grain, and at least one initiation element proximate at least one of the propellant grains. At least one pressure containment structure is secured to the housing and comprises a seal element expandable in response to gas pressure generated by combustion of a propellant grain of the at least one propellant structure. Related methods are also disclosed.

Downhole stimulation tools include a housing and at least one propellant structure within the housing comprising at least one propellant grain of a formulation, at least another propellant grain of a formulation different from the formulation of the at least one propellant grain longitudinally adjacent the at least one propellant grain, and at least one initiation element proximate at least one of the propellant grains. At least one pressure containment structure is secured to the housing and comprises a seal element expandable in response to gas pressure generated by combustion of a propellant grain of the at least one propellant structure. Related methods are also disclosed.

A central initiating charge according to embodiments of the invention includes a pellet. The pellet has a proximal end and a distal end. A central longitudinal axis spans from the proximal end to the distal end. A void spans longitudinally in said pellet. The void spans parallel to the central longitudinal axis.

An explosive booster shaped to fit into a blasthole adjacent a main explosive charge is provided. The booster comprises a body containing a charge of an explosive substance with a passage extending inwardly of the body to receive a detonator therein. The booster is configured to alter the shape of a detonation wave generated upon initiation of the detonator. In an embodiment, the booster includes a first and a second explosive substance, with the first explosive substance being shaped and selected to cause an outer portion of the detonation wave to accelerate relative to the remainder of the wave thereby altering the shape of the wave from a generally spherical wave to a generally planar wave. In an embodiment, the booster includes an internal member capable of altering the shape of the detonation wave.

Packaging systems with a rotatable table top held by a rotatable column, a plurality of circumferentially spaced apart clipper assemblies held at respective clipper stations provided by the rotatable table top, plurality of spaced apart pneumatic valves under the table top in fluid communication with the clipper assemblies, and at least one of: (a) a clipper reset cam assembly held under the rotatable table top with first and second reset cams cam that selectively automatically engage the pneumatic valves as the table rotates; and (b) a clipper trigger cam assembly held under the rotatable table top circumferentially spaced apart from the clipper reset cam assembly with first and second trigger cams that selectively automatically engage the pneumatic valves as the table rotates.