Abstract: A re-fracturing method using a perforating gun system in a multistring wellbore casing with an inner well casing installed in an outer well casing. The charges in the perforating system include a case, a liner positioned within the case, and an explosive filled within the liner. The liner shaped with a subtended angle about an apex of the liner such that a jet formed with the explosive creates an entrance hole in the inner well casing and the outer well casing; the liner having an exterior surface, the exterior surface substantially conical proximate the apex; the subtended angle of the liner ranges from 100° to 120°. The method includes covering the existing openings with the inner casing, perforating with the perforating system and creating constant diameter entrance holes in the outer casing and fracturing through the inner casing and outer casing.

Abstract: A re-fracturing method using a perforating gun system in a multistring wellbore casing with an inner well casing installed in an outer well casing. The charges in the perforating system includes include a case, a liner positioned within the case, and an explosive filled within the liner. The liner shaped with a subtended angle about an apex of the liner such that a jet formed with the explosive creates an entrance hole in the inner well casing and the outer well casing; the liner having an exterior surface, the exterior surface substantially conical proximate the apex; the subtended angle of the liner ranges from 100° to 120°. The method includes covering the existing openings with the inner casing, perforating with the perforating system and creating constant diameter entrance holes in the outer casing and fracturing through the inner casing and outer casing.

Abstract: A perforating gun and one or more volume-receiving surge canisters can be actuated at a time delay after perforation for creating a dynamic underbalance condition to aid in directing debris out of the perforations and fractures and into the wellbore. A timer and triggering device actuate one or more canisters in parallel or series after a pre-determined time delay or delays which can be related to wellbore conditions following perforation. Use of propellant-type perforating gun further benefits from favorable propellant burn conditions for forming perforations and followed thereafter by a perforation-cleaning underbalance pressure conditions characterized by one or more of an increased rate of change depression of the pressure in the adjacent annulus, a greater magnitude of pressure depression and a longer duration of underbalance.

Abstract: A perforating gun and one or more volume-receiving surge canisters can be actuated at a time delay after perforation for creating a dynamic underbalance condition to aid in directing debris out of the perforations and fractures and into the wellbore. A timer and triggering device actuate one or more canisters in parallel or series after a pre-determined time delay or delays which can be related to wellbore conditions following perforation. Use of propellant-type perforating gun further benefits from favorable propellant burn conditions for forming perforations and followed thereafter by a perforation-cleaning underbalance pressure conditions characterized by one or more of an increased rate of change depression of the pressure in the adjacent annulus, a greater magnitude of pressure depression and a longer duration of underbalance.

Abstract: A perforating gun and one or more volume-receiving surge canisters can be actuated at a time delay after perforation for creating a dynamic underbalance condition to aid in directing debris out of the perforations and fractures and into the wellbore. A timer and triggering device actuate one or more canisters in parallel or series after a pre-determined time delay or delays which can be related to wellbore conditions following perforation. Use of propellant-type perforating gun further benefits from favorable propellant burn conditions for forming perforations and followed thereafter by a perforation-cleaning underbalance pressure conditions characterized by one or more of an increased rate of change depression of the pressure in the adjacent annulus, a greater magnitude of pressure depression and a longer duration of underbalance.

Abstract: A perforating gun and one or more volume-receiving surge canisters can be actuated at a time delay after perforation for creating a dynamic underbalance condition to aid in directing debris out of the perforations and fractures and into the wellbore. A timer and triggering device actuate one or more canisters in parallel or series after a pre-determined time delay or delays which can be related to wellbore conditions following perforation. Use of propellant-type perforating gun further benefits from favorable propellant burn conditions for forming perforations and followed thereafter by a perforation-cleaning underbalance pressure conditions characterized by one or more of an increased rate of change depression of the pressure in the adjacent annulus, a greater magnitude of pressure depression and a longer duration of underbalance.

Abstract: A method and apparatus for perforating and stimulating a subterranean formation which is penetrated by a well bore having casing positioned therein so as to establish fluid communication between the formation and the well bore. A shell, sheath or sleeve of propellant material is positioned so as to substantially encircling at least one shaped charge in a subterranean well bore and is ignited due to the shock, heat and/or pressure generated from the detonated charge. Upon burning, the propellant material generates gases which clean perforations formed in the formation by detonation of the shaped charge(s) and which extend fluid communication between the formation and the well bore.