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.

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.

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.

A signal transfer assembly includes a signal transfer propellant assembly and a signal transfer connector tube in hydraulic communication with a signal transfer firing head. The signal transfer propellant assembly has a piston and a gas generating energetic material. The signal transfer connector tube has a bore and a first opening allowing fluid communication between a borehole fluid surrounding the connector tube and the bore. The piston generates a pressure pulse when propelled through the bore by the generated gas. The signal transfer firing head assembly includes a housing having a second opening allowing fluid communication between the housing bore and the borehole fluid. A related method includes forming a well tool by operatively connecting a signal transfer assembly as described above to a primary downhole tool and a secondary downhole tool; conveying the well tool into a wellbore using a work string; and activating the secondary downhole tool by initiating the primary downhole tool.

A firing head assembly for a well tool includes a shaft, a piston head, a biasing member, and a housing. The shaft has a nose and a terminal end. The shaft also includes a first shoulder and a second shoulder formed between the nose and the terminal end. The piston head slides along the shaft and is positioned between the retaining element and the first shoulder. The biasing member is mounted on the shaft and positioned between the piston head and the second shoulder. The housing has a bore in which the shaft, the piston head, and biasing member are disposed. The housing includes an opening allowing fluid communication between the housing bore and the borehole fluid external to the housing.

The present invention provides a method for further forming a plurality of small fractures in a main fracture. If a radial main fracture is further fractured axially to form a plurality of branch fractures, the stimulated volume of the oil and gas reservoir will be achieved to greatly increase the yield of dense oil and gas. The main contribution of the present invention is to form three-dimensional fracture networks for any low-permeability oil reservoirs to achieve stimulated reservoir volume. The concept is that an original main fracture is further fractured to form a plurality of branch fractures (the branch fractures form included angles with the original main fracture), and the locations for forming the branch fractures in the main fracture and even the size and length of the branch fractures can be controlled artificially, so that the branch fractures can be formed by fracturing where needed.

A firing head assembly for use with a perforating gun is described. The firing head assembly includes a tubular housing, first and second pistons, and a compressible member arranged within a lumen of the tubular housing and positioned between the first and second pistons. According to an aspect, the assembly includes a plurality of upper locking arms and lower locking arms that engage with locking members formed in the tubular housing. The firing head assembly further includes upper and lower shear washers arranged at the second opening of the tubular body, in a sandwich type configuration with respect to the second piston. Pressures within the firing head assembly may be adjusted to activate the firing head assembly to either trigger an explosive reaction or to not trigger the explosive reaction.

A composite drill gun for use in a wellbore environment can include a detonation housing containing a detonation source, a composite carrier containing one or more encapsulated charges, and a detonation train connecting the detonation source to the encapsulated charges. The detonation source and each individual encapsulated charge are all sealed with respect to the wellbore environment, and thus the carrier need not be sealed with respect to the wellbore environment. The carrier can be made out of composite materials without worry of leaks into the interior of the carrier, as the detonation source and encapsulated charges are all sealed with respect to the wellbore environment. The composite carrier can be easily drilled out of the wellbore after detonation.

A firing head assembly is described. The firing head assembly includes a tubular housing, upper piston and lower pistons, and a compressible member arranged within a lumen of the tubular housing and positioned between the upper and lower pistons. According to an aspect, the assembly includes a safety assembly that includes a sleeve having a zigzag shaped slot therein. The safety assembly may include a key that radially extends from a surface of one of the pistons, through the zigzag shaped slot. The distance between the upper and lower pistons may be adjusted by adjusting a pressure inside the tubular housing and a second pressure outside the tubular housing. The upper and lower pistons may function to operatively adjust the arrangement of the key within the zigzag shaped slot to activate the firing head assembly to either trigger an explosive reaction or to not trigger the explosive reaction.

A time delay tool and 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.