Abstract: Explosive devices and assemblies are described herein for use in geologic fracturing. Components of energetic material used in the explosive devices can be initially separated prior to inserting the assembled system down a wellbore, then later combined prior to detonation. Some exemplary explosive units for insertion into a borehole for use in fracturing a geologic formation surrounding the borehole can comprise a casing comprising a body defining an internal chamber, a first component of an explosive positioned within the internal chamber of the casing, and an inlet communicating with the internal chamber through which a second component of the explosive mixture is deliverable into the internal chamber to comprise the explosive.

Abstract: Explosive geologic fracturing methods, devices, and systems can be used in combination with other geologic fracturing means, such as hydraulic fracturing methods, devices and systems, or other fluid-based fracturing means. An exemplary method comprises introducing an explosive system into a wellbore in a geologic formation, detonating the explosive system in the wellbore to fracture at least a first portion of the geologic formation adjacent to the wellbore, and introducing pressurized fluid into the wellbore to enhance the fracturing of the first portion of the geologic formation. Such multi-stage fracturing can further enhance the resulting fracturing of geologic formation relative to explosive fracturing alone.

Abstract: In disclosed explosive units for use in a wellbore, the casing can include a tubular outer body comprising grooves, pockets, or other variances in thickness that create stress concentrations that promote shear and tensile fragmentation instead of ductile expansion of the casing, which can negatively impact permeability of a wellbore. In other embodiments, the casing can comprise non-ductile and/or reactive material which responds to explosive or high temperature loading by brittle failure, disintegration, melting, burning, and/or chemically reacting with the energetic materials and/or the borehole environment. Such embodiments can enhance the permeability of the wellbore after detonation.

Abstract: Detonation control modules and detonation control circuits are provided herein. A trigger input signal can cause a detonation control module to trigger a detonator. A detonation control module can include a timing circuit, a light-producing diode such as a laser diode, an optically triggered diode, and a high-voltage capacitor. The trigger input signal can activate the timing circuit. The timing circuit can control activation of the light-producing diode. Activation of the light-producing diode illuminates and activates the optically triggered diode. The optically triggered diode can be coupled between the high-voltage capacitor and the detonator. Activation of the optically triggered diode causes a power pulse to be released from the high-voltage capacitor that triggers the detonator.

Abstract: In disclosed explosive units for use in a wellbore, the casing can include a tubular outer body comprising grooves, pockets, or other variances in thickness that create stress concentrations that promote shear and tensile fragmentation instead of ductile expansion of the casing, which can negatively impact permeability of a wellbore. In other embodiments, the casing can comprise non-ductile and/or reactive material which responds to explosive or high temperature loading by brittle failure, disintegration, melting, burning, and/or chemically reacting with the energetic materials and/or the borehole environment. Such embodiments can enhance the permeability of the wellbore after detonation.

Abstract: Explosive geologic fracturing methods, devices, and systems can be used in combination with other geologic fracturing means, such as hydraulic fracturing methods, devices and systems, or other fluid-based fracturing means. An exemplary method comprises introducing an explosive system into a wellbore in a geologic formation, detonating the explosive system in the wellbore to fracture at least a first portion of the geologic formation adjacent to the wellbore, and introducing pressurized fluid into the wellbore to enhance the fracturing of the first portion of the geologic formation. Such multi-stage fracturing can further enhance the resulting fracturing of a geologic formation relative to explosive fracturing alone.

Abstract: Explosive devices and assemblies are described herein for use in geologic fracturing. Components of energetic material used in the explosive devices can be initially separated prior to inserting the assembled system down a wellbore, then later combined prior to detonation. Some exemplary explosive units for insertion into a borehole for use in fracturing a geologic formation surrounding the borehole can comprise a casing comprising a body defining an internal chamber, a first component of an explosive positioned within the internal chamber of the casing, and an inlet communicating with the internal chamber through which a second component of the explosive mixture is deliverable into the internal chamber to comprise the explosive.

Abstract: Detonation control modules and detonation control circuits are provided herein. A trigger input signal can cause a detonation control module to trigger a detonator. A detonation control module can include a timing circuit, a light-producing diode such as a laser diode, an optically triggered diode, and a high-voltage capacitor. The trigger input signal can activate the timing circuit. The timing circuit can control activation of the light-producing diode. Activation of the light-producing diode illuminates and activates the optically triggered diode. The optically triggered diode can be coupled between the high-voltage capacitor and the detonator. Activation of the optically triggered diode causes a power pulse to be released from the high-voltage capacitor that triggers the detonator.