An ultra-short, high-density, perforating gun for use in a well casing includes a gun carrier extending along a longitudinal axis, only 2 charges located inside the gun carrier, the only 2 charges being positioned in a single plane transverse to the longitudinal axis, and a charge holder configured to carry the only 2 charges, the charge holder configured to be inserted into the gun carrier. The gun carrier ranges in length from 4 inches to 11 inches. A diameter of the gun carrier ranges from 1 to 4 inches, and wherein at least one charge of the only 2 charges has a liner that has a subtended angle from 100° to 120°.

A firing head assembly may include a tubular housing; a valve slidably disposed within the tubular housing; a lock mandrel disposed in the tubular housing between the valve and the tubular housing second end; a firing pin holder disposed in the tubular housing between the lock mandrel and the tubular housing second end; an engagement mechanism operably contacting the lock mandrel and the firing pin holder latch. The valve may have a piston end exposed to the lumen. The lock mandrel may be restrained from axial movement by a shear element. The firing pin holder may include a firing pin and latch. The engagement mechanism may be switchable between an engaged arrangement and a disengaged arrangement. The engagement mechanism may be configured to transition from the engaged arrangement to the disengaged arrangement in response to an axial movement of the lock mandrel.

A perforating gun assembly may include a first housing extending along a longitudinal axis and a tandem seal adapter (TSA). The first housing may include a coupling provided at a first end of the first housing. The TSA may include a TSA body and a seal element provided on an outer surface of the TSA body. At least part of the TSA may be positioned inside the first housing such that the seal element and the coupling intersect with a common plane that is perpendicular to the longitudinal axis.

An interchangeable module configured to be used in an integrated perforating gun and setting tool system, the interchangeable module having a body having a chamber, a first electrical connection located at a first end of the chamber, and a second electrical connection located at a second end of the chamber. The first end is opposite to the second end. An addressable switch located inside the chamber, the addressable switch has a digital address. A connection unit located inside the chamber and configured to electrically connect the addressable switch to an initiating device. The interchangeable module is configured to be used (1) between a first gun cluster and a second gun cluster and (2) between a distal gun cluster and a setting tool, and the first and second electrical connections are electrically connected to the addressable switch.

A perforating gun, system and method is provided. The perforating gun includes a body, a plurality of shaped charges, at least one initial propellant and may include an actuating mechanism. The plurality of shaped charges are mounted within the body, and each shaped charge has an amount of an explosive material. The actuating mechanism is in communication with each shaped charge and the at least one initial propellant. The actuating mechanism is configured to fire the at least one initial propellant before firing any of the plurality of shaped charges.

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.

An apparatus for use in a well bore is described herein. The apparatus includes a one-piece housing having a length in an axial direction from a first end to a second end, and end wall and a sidewall defining a cavity within the housing. The apparatus also includes a frame inside the cavity. The frame includes a charge receptacle, a detonator receptacle, a first electrical contact and a second electrical contact. The apparatus further includes a conductive material coupled with the first electrical contact.

A gun-tube extension has (1) a body portion, (2) a first end configured to connect to an end cap of a gun tube, and (3) a second end configured to be connected to a sub-assembly. The gun-tube extension may rotate either by the operation of gravity on weights or by a motor. The gun-tube extension may include an orientation-detection device, such as an accelerometer, which may be part of an addressable switch. A ground for a gun tube or gun-tube extension may include a bow spring attached to and in electrical communication with the gun tube housing or the gun-tube extension housing. An end cap may include indexing indicia to orient a gun tube to a desired rotational position and/or may be structured to fit different diameter gun tubes.

A perforating gun connection whereby a signal may be carried from surface, down through a wireline or other conveyance, and across the connection from the pin on one perforating gun to an electrical contact structure on the next perforating gun in the string. In an example, the connection includes a connector body with an electrical pin positioned for contact with an electrical contact structure on the next perforating gun. The electrical contact structure has a contact tab aligned for engagement by the pin when connected with the connector body. The electrical contact structure may be unitarily formed to include a number of features to facilitate connection between perforating guns.

An initiator system for actuating a wellbore setting tool for a plug or a packer. The initiator system includes a firing head that comprises a tubular body defining a bore, wherein the bore has an upstream chamber and a downstream chamber. A tubular bulkhead that resides within the bore of the firing head. The initiator system further includes a signal pin that has an elongated shaft residing within the tubular bulkhead. The initiator system also includes an ignition tube forming an ignition chamber between upstream and downstream ends. The upstream end of the ignition tube receives a second end of the tubular bulkhead. The initiator system further includes an ignitor that is in electrical communication with the signal pin. The initiator system also has an explosive component which resides within the ignition chamber at the downstream end, and is configured to initiate when the signal pin transmits an actuation signal to the igniter.