Casing conveyed, externally mounted perforation concept

A well system, comprising:

• a wellbore extending from a terranean surface through a subterranean formation;
• a wellbore casing positioned within the wellbore;
• and
• a downhole perforating device positioned in the subterranean formation along an outer surface of the wellbore casing, the downhole perforating device including:
• a perforating structure surrounding at least a portion of the outer surface of the wellbore casing;
• one or more perforation elements at least partially embodied within the perforating structure, the one or more perforation elements positioned to perforate the wellbore casing to an inside thereof;
• and
• electronics at least partially embodied within the perforating structure, the electronics for triggering the one or more perforation elements.

A method for perforating a well system, comprising:

• positioning a downhole perforating device in a subterranean formation along an outer surface of a wellbore casing, the downhole perforating device including:
• a perforating structure surrounding at least a portion of the outer surface of the wellbore casing;
• one or more perforation elements at least partially embodied within the perforating structure, the one or more perforation elements positioned to perforate the wellbore casing to an inside thereof;
• and
• electronics at least partially embodied within the perforating structure, the electronics for triggering the one or more perforation elements;
• and
• triggering the one or more perforation elements to form one or more perforations in the wellbore casing.