An explosive system for fracturing an underground geologic formation adjacent to a wellbore can comprise a plurality of explosive units comprising an explosive material contained within the casing, and detonation control modules electrically coupled to the plurality of explosive units and configured to cause a power pulse to be transmitted to at least one detonator of at least one of the plurality of explosive units for detonation of the explosive material. The explosive units are configured to be positioned within a wellbore in spaced apart positions relative to one another along a string with the detonation control modules positioned adjacent to the plurality of explosive units in the wellbore, such that the axial positions of the explosive units relative to the wellbore are at least partially based on geologic properties of the geologic formation adjacent the wellbore.

An explosive system for fracturing an underground geologic formation adjacent to a wellbore can comprise a plurality of explosive units comprising an explosive material contained within the casing, and detonation control modules electrically coupled to the plurality of explosive units and configured to cause a power pulse to be transmitted to at least one detonator of at least one of the plurality of explosive units for detonation of the explosive material. The explosive units are configured to be positioned within a wellbore in spaced apart positions relative to one another along a string with the detonation control modules positioned adjacent to the plurality of explosive units in the wellbore, such that the axial positions of the explosive units relative to the wellbore are at least partially based on geologic properties of the geologic formation adjacent the wellbore.

The present utility model relates to a container or receptacle for containing a mixture, preferably pentolite, used to initiate a blasting process. Said container comprises at least one lower part intended to contain the mixture of explosive material, and an upper part or cover intended to maintain the structural unity of the container and prevent the mixture from leaving of the container, wherein said lower part comprises an elongated hollow structure with a base, and a duct or pin inside the same, which extends from the base of the lower part of the container to a defined distance of the upper end of the lower part, wherein the duct or pin is opened at both ends, and wherein the cover of the container comprises an opening, which is supplemented by the upper part of the opened duct or pin, and comprises at least one opening, from which a respective duct or pin extends towards the lower part of the cover, where said duct or pin is closed in the lower part thereof.

There is an igniter system for igniting an energetic material. The igniter system includes a housing having a bore; an igniter located inside the bore; a ground wire directly connected to the igniter; and a signal wire directly connected to the igniter. The ground wire and the signal wire form an electrical circuit with the igniter for igniting the energetic material.

There is a downhole tool that includes a switch sub having a bore and a bulkhead extending along a longitudinal axis, wherein the bulkhead has a bulkhead bore that fluidly communicates with (i) the bore and (ii) an outside of the switch sub; and an igniter system located inside the bulkhead. The igniter system is configured to ignite an energetic material.

An explosive assembly includes a first explosive unit having a first longitudinal end portion having a first mechanical coupling feature, a second explosive unit having a second longitudinal end portion having a second mechanical coupling feature, and a tubular connector having a first end portion mechanically coupled to the first mechanical coupling feature and a second end portion mechanically coupled to the second mechanical coupling feature, such that the first explosive unit, the connector, and the second explosive unit are connected together end-to-end along a common longitudinal axis. Each explosive unit can contain a high explosive material and a detonator, and the connector can comprise a detonation control module electrically coupled to the detonators and configured to detonate the explosive units.

An explosive assembly includes a first explosive unit having a first longitudinal end portion having a first mechanical coupling feature, a second explosive unit having a second longitudinal end portion having a second mechanical coupling feature, and a tubular connector having a first end portion mechanically coupled to the first mechanical coupling feature and a second end portion mechanically coupled to the second mechanical coupling feature, such that the first explosive unit, the connector, and the second explosive unit are connected together end-to-end along a common longitudinal axis. Each explosive unit can contain a high explosive material and a detonator, and the connector can comprise a detonation control module electrically coupled to the detonators and configured to detonate the explosive units.

A charge comprises a case, the bottom of which has disposed therein an explosive cartridge, on the inside surface of which cartridge there is mounted a liner. Opposite the bottom, an upper portion of the case is cylindrical and threaded and is provided with a threaded bushing, which is mounted such as to abut the liner and has a through aperture with a diameter that is less than the inside diameter of the liner. The threaded sleeve has an internal or an external thread and the upper portion of the case has an external or an internal thread accordingly. The threaded sleeve has recesses about its periphery for the installation of a removable turning means. The bottom and the outside surface of the cartridge are conical. The liner is configured with a cylindrical shoulder in its upper part and has a height which is greater than that of the cartridge.

A charge comprises a case, the bottom of which has disposed therein an explosive cartridge, on the inside surface of which cartridge there is mounted a liner. Opposite the bottom, an upper portion of the case is cylindrical and threaded and is provided with a threaded bushing, which is mounted such as to abut the liner and has a through aperture with a diameter that is less than the inside diameter of the liner. The threaded sleeve has an internal or an external thread and the upper portion of the case has an external or an internal thread accordingly. The threaded sleeve has recesses about its periphery for the installation of a removable turning means. The bottom and the outside surface of the cartridge are conical. The liner is configured with a cylindrical shoulder in its upper part and has a height which is greater than that of the cartridge.

There is a downhole tool that includes a switch sub having a bore and a bulkhead extending along a longitudinal axis, wherein the bulkhead has a bulkhead bore that fluidly communicates with (i) the bore and (ii) an outside of the switch sub; and an igniter system located inside the bulkhead. The igniter system is configured to ignite an energetic material.