摘要 |
Disclosed is a casing conveyed perforating system and methods for externally perforating a wellbore and casing. The perforating system is attached to the outside of the casing and is conveyed along with the casing when it is inserted into the wellbore. The perforation may be accomplished using two groups of charges, which are contained in protective pressure chambers, however, may use only one group of bi-directional charges. Each pressure chamber may be positioned radially around the outside of the wellbore casing. The pressure chambers form longitudinally extending ribs, which conveniently serve to center the casing within the wellbore. One group of charges may be aimed inward in order to perforate the casing, while the other group of charges is aimed outward in order to perforate the formation.
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