A releasable tool using an electronic motor to drive a differential to engage or release a quick change sub that may be coupled to additional downhole tools, such as a perforating gun string.

A downhole perforation drone includes a body comprising a material configured to dissolve over time. The body includes a first portion and a second portion. The first portion includes one or more sensors to determine a depth and position of the drone within a wellbore, a communications system configured to exchange wireless signals with a surface device, a perforation charge circuit to cause perforation charges to ignite, and a microcontroller to perform operations, including causing the perforation charge circuit to ignite the perforation charges. The second portion includes a plurality of perforation charges, the plurality of perforation charges to ignite upon receiving an instruction from the perforation charge circuit. The microcontroller can determine the position of the drone within the wellbore from sensor information and automatically instruct the perforation charges to ignite based on the position of the downhole perforation drone within the wellbore.

Autonomous units and methods for downhole, multi-zone perforation and fracture stimulation for hydrocarbon production. The autonomous unit may be a perforating gun assembly, a bridge plug assembly, or fracturing plug assembly. The autonomous units are dimensioned and arranged to be deployed within a wellbore without an electric wireline. The autonomous units may be fabricated from a friable material so as to self-destruct upon receiving a signal. The autonomous units include a position locator for sensing the presence of objects along the wellbore and generating depth signals in response. The autonomous units also include an on-board controller for processing the depth signals and for activating an actuatable tool at a zone of interest.

A method and apparatus for sealing a well conduit includes moving a plugging tool (21) to a first position in the well conduit, the plugging tool (21) comprising a perforating tool (12) and a hollow mandrel (8) with a heater (8) inside and a meltable material on the outside. The perforating tool (12) is actuated to create openings in the well conduit. The heater (8) is operated to melt or activate the material disposed on an exterior of the mandrel (9). The melted material is allowed to solidify in the conduit to form a plug and to flow into the openings to fill a cross-section of an annular space outside the conduit. A logging tool (2) may thereafter be inserted into the hollow mandrel (9) to check the integrity of the plug.

A perforating gun assembly that orients one or more shaped charges within a well includes a housing and an orienting internal assembly configured to be disposed within a longitudinal bore of the housing. The orienting internal assembly may include at least one shaped charge holder or charge tube, a rotation support system, a detonator holder and/or a detonator. The rotation support system may be configured so that the detonator holder and/or detonator rotate together as a whole with the at least one shaped charge holder or charge tube. The rotation support system may include at least one bearing assembly, a plurality of rollers, or combinations thereof. The orienting internal assembly may be configured for gravitational orientation.

A method of sealing a partly or entirely annulus-cemented casing portion of a first casing in a second casing in a petroleum well, includes running a drill pipe string-conveyed perforating gun with a cement shattering device into said well; positioning said perforating gun at said cemented casing portion and activating first, shallow-perforating charges to make first, shallow perforations through said casing portion into thus making a perforated, cement-filled annulus portion and leaving said second casing intact; activating said cement shattering device to disintegrate all or part of said cement within said first perforated annulus portion; running a washing tool along said perforated casing portion, washing out said shattered cement from said perforated annulus portion. The washed-out casing portion may then be cut using a cutter tool and pulled out of hole, or cemented using a cementing tool, or a combination thereof.

A self-orienting internal assembly for use in a perforating gun housing may include a charge carrier and a first rotation assembly coupled to the charge carrier. The charge carrier may include a shaped charge holder configured to hold a shaped charge and a detonator holder configured to receive a detonator therein and coupled to a first end of the shaped charge holder. The first rotation assembly being configured to contact an interior surface of the perforating gun housing.