A time delay tool and method in a wellbore casing is disclosed. The tool/method includes a mechanical restraining element, a reservoir for containing a reactive fluid, an actuating device and a wellbore device. When a stored energy is applied on the wellbore device, the actuation device is actuated and enables the reactive fluid in the reservoir to come in contact with the mechanical restraining element. While the mechanical restraining element undergoes a change in shape due to a chemical reaction, a stored energy applied on the wellbore device is delayed by a pre-determined time delay. The amount of the pre-determined time delay is determined by factors that include the reactive fluids, concentration of the reactive fluids, geometry and size of the mechanical restraining element.

A gun to gun transfer delay fuse that includes a delay housing, a first cylindrical cavity housing a firing pin and igniter, and a second cylindrical cavity housing a delay fuse with a centralizer feature.

A time delay tool and method in a wellbore casing is disclosed. The tool/method includes a mechanical restraining element, a reservoir for containing a reactive fluid, an actuating device and a wellbore device. When a stored energy is applied on the wellbore device, the actuation device is actuated and enables the reactive fluid in the reservoir to come in contact with the mechanical restraining element. While the mechanical restraining element undergoes a change in shape due to a chemical reaction, a stored energy applied on the wellbore device is delayed by a pre-determined time delay. The amount of the pre-determined time delay is determined by factors that include the reactive fluids, concentration of the reactive fluids, geometry and size of the mechanical restraining element.

A time delay apparatus for use with a downhole tool in a wellbore casing. In an exemplary embodiment, the apparatus includes an electronic circuit comprising a timer, a fusible link, a split spool device that includes a center pin held in place in a restrained position with a spool and a spring element surrounding the spool. A pressure applied to a trigger device, such as a rupture disk, activates a pressure switch and starts a timer, configured with a preset countdown time, in the electronic circuit. On expiration of the timer, the timer block of the electronic circuit generates a signal to cause breaking of the fusible link and releasing of the spring element such that the center pin of the split spool travels to a functional position and activates the downhole tool.

A mechanical firing system is used to detonate energetic material, such as external perforating charges, disposed on an apparatus deployed on tubing in a wellbore. In one embodiment, a through-bulkhead explosive energy transfer is used to deliver the detonation from the mechanical firing system to an external detonator. In another embodiment, the mechanical firing system delivers an electric pulse to initiate a detonator. A through-wire pressure bulkhead isolates the source of electric power from the wellbore environment. The electrical source can be a magneto-based device or can use a piezoelectric device.

A re-fracturing method involves placement and centralization of a liner string that has shaped charges at predetermined locations that are externally isolated with packers. The shaped charges can be set off in a desired order and re-fracturing can then take place in new locations. In a bottom up order for perforating sequentially larger balls can be landed on seats and developed pressure or component movement generated by applying pressure can be used to set a shaped charge and isolate portions of the borehole below. The balls and even the seats can be later milled out or just allowed to disintegrate or dissolve with well fluids that are present or later added to clear the liner for subsequent production. Alternatively, the liner could be removed by release of the packers before production or injection begins.

A one trip system for perforating and fracking multiple intervals uses a releasable barrier. The barrier can be an inflatable. A pressure booster system is associated with the BHA so that the existing hydrostatic pressure is boosted when the gun or portions thereof are fired. After firing in one interval, the BHA is raised and the barrier is redeployed and the pattern repeats. Instruments allow sensing the conditions in the interval for optimal placement of the gun therein and for monitoring flow, pressure and formation conditions during the fracturing. Circulation between gun firings cleans up the hole. If run in on wireline a water saving tool can be associated with the BHA to rapidly position it where desired. A multitude of perforation charges mounted in the BHA can be selectively fired by selected corresponding detonator based on a predetermined sequence or surface telemetry command.

An improved plug for sealing a tubular as described. The improved plug comprises a plug body, the plug body comprising a propellant and an initiator adapted to initiate the propellant upon a signal. Upon initiation the propellant deflagrates causing the plug body to at least partially disintegrate.

In accordance with embodiments of the present disclosure, systems and methods for safely, and cost-effectively activating a mechanical perforator using a pyrotechnic initiated hydrostatic activating mechanism. The mechanism includes a piston connected to a power rod. The piston is activated by the rupturing of a disc, which separates a first chamber from a second chamber containing the piston. Upon rupturing of the disc, wellbore fluids fill the second chamber forcing the piston to move from a first position to a second position, which causes activation of the mechanical perforator. The first chamber may optionally be filled with a pressurized gas, such as nitrogen or air, to add a boost assist to activation of the piston.

A firing assembly for a wellbore perforating gun or other downhole tool includes: one or more casings connected together to form a firing head containment body, the firing head containment body is in fluid communication with a firing assembly that includes a click pressure firing module that allows the wellbore to be pressurized to high pressures required for pressure testing the well casing one or more times without firing the gun or actuating a certain downhole tool, and after a predetermined number of pressure increase events, allows the subsequent high pressure activation to reach the firing pin or actuation device and fire the gun or activate the tool without further activity from the surface other than applying the pressure.