An apparatus and method according to which a perforating gun includes a volume fill body. The volume fill body is positioned in the space between a charge tube and a carrier tube. The fill body occupies at least part, and sometimes all, of the free volume space between the charge tube and carrier tube thereby reducing the free volume space. In certain downhole applications, large free volume space can lead to significant reductions in wellbore pressure, causing dynamic underbalance, which is undesirable. The presence of the volume fill body prevents, or at least reduces, dynamic underbalance and its effects. Also, the volume fill body aligns the charge tube with the carrier tube, further assisting perforation.

A vibration-damping sub is provided to mitigate shock and other sources of vibration in a tool string. In examples, a tubular damping body is rigidly coupled between a vibration-sensitive tool and a vibration source. The tubular damping body includes a tubular wall defining a plurality of shaped holes configured to dampen the mechanical vibration to below the design threshold for the vibration-sensitive tool. The tubular damping body may also include different portions having different materials and impedances to further disrupt the propagation of mechanical waveforms.

An impact sleeve is used for mitigating damage in a perforating gun resulting from shaped charge detonation. In one example, a perforating gun includes a gun carrier, with a charge holder and the impact sleeve inside the gun carrier. The charge holder holds a plurality of shaped charges capable of being detonated with sufficient explosive energy to generate high-velocity fragments inside the gun carrier. The impact sleeve comprises an energy-absorbing material and optional raised features for absorbing at least some energy of the high-velocity fragments. The materials, raised features, positioning, and geometry of the impact sleeve and raised features may be tuned to optimize energy absorption.

Systems and methods are provided for laser heating in a fluid environment (30). Such a system may include a laser generator (12) and a laser output sub (16) separate from one another via an optical fiber (18). The laser generator may generate a heating laser pulse over the optical fiber. The laser output sub may emit the heating laser pulse to heat a substrate (22) in the fluid environment (30). To enable the heating laser pulse to pass between the laser output sub (16) and the substrate (22), the laser output sub may dispense a laser-transmissive optical grease or a laser-transmissive magnetic fluid, or may generate a vacuum cavitation bubble in the fluid between the laser output sub (16) and the substrate (22).

A method and systems for perforating a formation surrounding a borehole that include placing a perforating gun assembly into the borehole, the perforating gun assembly including a gun body comprising a connector and a shaped charge within the gun body. The shaped charges are detonated, thereby producing a shock wave in the gun body. The shock wave propagating through the gun body is attenuated using a shock attenuation feature in the gun body to decrease a stress from the shock wave communicated to the connector.

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 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 vibration-damping sub is provided to mitigate shock and other sources of vibration in a tool string. In examples, a tubular damping body is rigidly coupled between a vibration-sensitive tool and a vibration source. The tubular damping body includes a tubular wall defining a plurality of shaped holes configured to dampen the mechanical vibration to below the design threshold for the vibration-sensitive tool. The tubular damping body may also include different portions having different materials and impedances to further disrupt the propagation of mechanical waveforms.

A system, method, and device for monitoring a parameter downhole. The system comprises a conveyance string locatable in the wellbore, a sensor and a recorder located on the conveyance string, and a processor in communication with the recorder. The recorder comprises a sampler in communication with the sensor, and the sampler is operable to sample the measured parameter at a sampling rate of 150 kHz to 10 MHz. The recorder also comprises an information storage device in communication with the sampler and operable to store the samples acquired by the sampler. The processor is operable to monitor the parameter based on the samples collected by the sampler.

Techniques of the present disclosure relate to downhole perforation operations using fluid containing hollow spheres. A method comprising: disposing a perforating apparatus in a volume of hollow particles in a wellbore; and detonating the perforating apparatus to collapse a portion of the hollow particles to increase flow through at least one perforation resulting from a detonation.