Methods and apparatus for perforating and treating production zones and otherwise performing related activities within a well

Apparatus for use in perforating one or more zones of a well bore, comprising

• a tubular housing connectable as part of a casing string to be lowered into and anchored within the well bore by a column of cement between it and the well bore,
• a perforating sleeve mounted for shifting between first and second positions within the housing bore and carrying shaped charges on its outer side facing the bore of the housing,
• means sealing between the sleeve and housing bore to enclose the shaped charges within a sealed chamber when the sleeve is in its first position,
• means by which the charges may be detonated to perforate the housing and the cement column thereabout,
• means by which the perforating sleeve may be shifted, following detonation, to its second position in the housing bore to uncover the perforations therein,
• a seal sleeve mounted in a first position within the housing bore adjacent the perforating sleeve and being shiftable into a second position covering the perforations in the housing bore following shifting of the perforating sleeve to its second position, the seal sleeve then being shiftable back to the first position,
• means sealing between the seal sleeve and housing bore to close off the perforations in said second position.

Apparatus for use in perforating one or more zones of a well bore, comprising

• a perforating assembly including a tubular housing connectible as part of a casing string to be lowered into and anchored within the well bore by a column of cement between the casing string and well bore and having an enclosed chamber in which shaped charges are mounted in position to perforate the housing and cement column opposite a selected zone, and
• means for detonating the charges, including
• a detonator wired to the shaped charges,
• a firing pin positioned to strike the detonator in order to detonate the charges,
• a trigger extending into the chamber and having an inner end movable, in response to activation of its outer end, from a first inactive position to a second position striking the firing pin, and
• detent means releasably holding said trigger in its first inactive position,
• said trigger having means intermediate the detent means and its outer end which is responsive to activation of its outer end to accumulate energy which, at a predetermined level, causes the detent means to be released.

In a well having a casing string anchored within a well bore by a column of cement in the annulus between the casing string and well bore which penetrates a plurality of zones in the well, apparatus for perforating the zones comprising

• a plurality of perforating assemblies each having
• a housing with a bore therethrough installed in the string at a location opposite one of the zones,
• a perforating sleeve mounted within the housing bore and having shaped charges carried with an enclosed chamber in position to perforate the housing and string upon detonation,
• a trigger extending from the chamber into the bore of the housing, and
• a work string lowerable through the casing string and having means thereon sequentially engagable with the trigger of each assembly, as the string is moved vertically in the casing string, so as to successively detonate the charges of selected perforating sleeves.

Well apparatus, comprising

• a tubular housing connectable as part of a well pipe for lowering therewith into a well conduit disposed within a well bore,
• a perforating sleeve mounted in the housing and carrying perforating means within a sealed chamber between the sleeve and housing,
• means by which the perforating means may be activated in order to form perforations in one of the sleeve and housing, and
• means by which the sleeve may be shifted, following formation of the perforations, to open the interior of the well pipe to the annulus between it and the well conduit.