Abstract: A firing head for selectively activating an initiator of a downhole tool may include a housing, a pin, and a moveable stopper. The housing may have a bore and a radially enlarged chamber formed along the bore. The pin is disposed in the bore and has a circumferential groove formed on an outer surface of the shank. The moveable stopper is disposed in the radially enlarged chamber. The stopper is only partially disposed in the groove when the housing is in a vertical position. The stopper moves out of the groove when the housing has a predetermined minimum angular deviation from the vertical position.

Abstract: A firing head for selectively activating an initiator of a downhole tool may include a housing, a pin, and a moveable stopper. The housing may have a bore and a radially enlarged chamber formed along the bore. The pin is disposed in the bore and has a circumferential groove formed on an outer surface of the shank. The moveable stopper is disposed in the radially enlarged chamber. The stopper is only partially disposed in the groove when the housing is in a vertical position. The stopper moves out of the groove when the housing has a predetermined minimum angular deviation from the vertical position.

Abstract: An apparatus for use with a perforating gun includes a charge tube and at least one endplate. The charge tube has a cylindrical wall, a first end, an upper opening formed proximate to the first end, and a lower opening formed proximate to the first end. The at least one endplate has a central insert having a first section projecting from a second section. The first section seats in the upper opening of the first end and the second section seats in the lower opening of the first end.

Abstract: A well tool (60) includes a perforating gun (108), a sealing element (130), at least one pressure sensor (150), a detector (132), a controller (152), and an anchor (134). The perforating gun (108) perforates the wellbore tubular in response to a firing signal. The sealing element (130) is connected to the perforating gun (108) and generates a pressure differential thereacross. The at least one pressure sensor (150) is associated with the sealing element (130) and detects a surface transmitted pressure signal. The detector (132) detects at least one marker (70) positioned along the wellbore (12) and which includes a perforating marker (70) associated with a perforating depth.