A wellbore perforating apparatus and method according to which a perforating gun and a sensor sub are run into a wellbore toward a downhole location at which the wellbore is to be perforated. Detonable components of the perforating gun are energized to perforate the wellbore at the downhole location. An acceleration of the perforating gun and a pressure and a temperature of the wellbore are detected using the sensor sub during a time interval encompassing the energization of the detonable components. The detected acceleration, pressure, and temperature are compared to benchmark energetic responses for both detonation and deflagration events. Based on this comparison, a decision can be made as to whether an incubation period is needed to allow a reaction of the detonable components to weaken before retrieving the perforating gun from the wellbore.

A firing head assembly is described. The firing head assembly includes a tubular housing, upper piston and lower pistons, and a compressible member arranged within a lumen of the tubular housing and positioned between the upper and lower pistons. According to an aspect, the assembly includes a safety assembly that includes a sleeve having a zigzag shaped slot therein. The safety assembly may include a key that radially extends from a surface of one of the pistons, through the zigzag shaped slot. The distance between the upper and lower pistons may be adjusted by adjusting a pressure inside the tubular housing and a second pressure outside the tubular housing. The upper and lower pistons may function to operatively adjust the arrangement of the key within the zigzag shaped slot to activate the firing head assembly to either trigger an explosive reaction or to not trigger the explosive reaction.

A method of perforating a subterranean formation may comprise: inserting into a wellbore a perforating gun assembly comprising: a first gun assembly comprising a first perforating explosive and a first ballistic transfer element; a transfer assembly comprising a second ballistic transfer element; and a second gun assembly comprising a second perforating explosive, wherein the first gun assembly and the second gun assembly are separated from the transfer assembly by a discontinuity; detonating the first perforating explosive; propagating a ballistic signal from the first gun assembly, across the discontinuity, to the transfer assembly; propagating a ballistic signal though the transfer assembly to the second ballistic transfer element; propagating a ballistic signal from the transfer assembly, across the discontinuity, to the second gun assembly; and detonating the second perforating explosive.

A shock sensor, comprising: a housing, wherein the housing is cylindrical, wherein the housing comprises: a first end; a second end; a central bore that traverses a length of the housing; and an internal cavity; a coil, wherein the coil is disposed about the central bore; at least two magnets, wherein the at least two magnets are disposed about the central bore; a spring, wherein the spring is a compression spring, wherein the spring is disposed within the housing, wherein the spring comprises a first end and a second end; and a metallic member, wherein the metallic member is disposed at the second end of the spring.

A method for firing a detonator in a chain of switch assemblies includes a step of lowering the chain of switch assemblies into a wellbore; a step of powering-up a switch assembly of the chain of switch assemblies; a step of independently entering through a set of states during which the switch assembly interacts with a downstream switch assembly and determines a status of one or more elements associated with the switch assembly; and a step of firing a detonator electrically connected to the switch assembly or entering a sleeping state.

A firing head assembly is described. The firing head assembly includes a tubular housing, upper piston and lower pistons, and a compressible member arranged within a lumen of the tubular housing and positioned between the upper and lower pistons. According to an aspect, the assembly includes a safety assembly that includes a sleeve having a zigzag shaped slot therein. The safety assembly may include a key that radially extends from a surface of one of the pistons, through the zigzag shaped slot. The distance between the upper and lower pistons may be adjusted by adjusting a pressure inside the tubular housing and a second pressure outside the tubular housing. The upper and lower pistons may function to operatively adjust the arrangement of the key within the zigzag shaped slot to activate the firing head assembly to either trigger an explosive reaction or to not trigger the explosive reaction.

The disclosure relates to perforating systems for perforating the casing of a wellbore. The perforating systems contain insensitive high explosives. The disclosure also relates to shaped charges containing insensitive high explosives for use in such perforating systems. The disclosure further relates to methods of using such perforating systems to perforate the casing of a wellbore.

The disclosure relates to perforating systems for perforating the casing of a wellbore. The perforating systems contain insensitive high explosives. The disclosure also relates to shaped charges containing insensitive high explosives for use in such perforating systems. The disclosure further relates to methods of using such perforating systems to perforate the casing of a wellbore.

A system and method for confirming ignition of a fuel source in a wellbore. The system includes a tool, a fuel source associated with the tool, a control unit to ignite the fuel source, and a sensor to receive an ignition parameter corresponding to the fuel source. The ignition parameter indicates that ignition of the fuel source has occurred.

A method for firing a detonator in a chain of switch assemblies includes a step of lowering the chain of switch assemblies into a wellbore; a step of powering-up a switch assembly of the chain of switch assemblies; a step of independently entering through a set of states during which the switch assembly interacts with a downstream switch assembly and determines a status of one or more elements associated with the switch assembly; and a step of firing a detonator electrically connected to the switch assembly or entering a sleeping state.