An apparatus for applying a magnetic pressure to a work piece includes an inductor configured to be disposed in proximity to the work piece and a controller electrically connected to the inductor and configured to control a supply of electrical power in order to output a first voltage over a selected frequency range to determine a frequency that provides a maximum current or a frequency that provides a current within a selected range of the maximum current to the inductor.

An apparatus for applying a magnetic pressure to a work piece includes an inductor configured to be disposed in proximity to the work piece and a controller electrically connected to the inductor and configured to control a supply of electrical power in order to output a first voltage over a selected frequency range to determine a frequency that provides a maximum current or a frequency that provides a current within a selected range of the maximum current to the inductor.

A downhole oscillation tool and method for axially vibrating a drill bit. In some embodiments, modular actuation assemblies may be provided, which may be readily interchanged between a housing and a shaft to axially vibrate the shaft with respect to the housing. Modular actuation assemblies may be mechanical, hydraulic, electric, or piezoelectric, for example, and may be characterized by differing oscillation frequencies. In some embodiments, a piezo element may be provided between the housing and the shaft.

A flow control device for use with a subterranean well, can include inner and outer flow trim sleeves. A radial spacing between the inner and outer flow trim sleeves increases in a direction of flow through the radial spacing. A method of regulating flow between an interior and an exterior of a tubular string in a well can include displacing at least one of inner and outer flow trim sleeves in a direction, a radial spacing between the inner and outer trim sleeves increasing in the direction. Another flow control device can include inner and outer flow trim sleeves, and a flow area through the radial spacing increases in a direction of flow through the radial spacing.

A downhole oscillation tool and method for axially vibrating a drill bit. In some embodiments, modular actuation assemblies may be provided, which may be readily interchanged between a housing and a shaft to axially vibrate the shaft with respect to the housing. Modular actuation assemblies may be mechanical, hydraulic, electric, or piezoelectric, for example, and may be characterized by differing oscillation frequencies. In some embodiments, a piezo element may be provided between the housing and the shaft.

A jarring tool includes a main body having a central bore extending therein, an upper connection at a proximal end of the main body for attaching the jarring tool to wireline or slickline, a lower portion at a distal end of main body, and a reciprocating hammer fixed at a first position within the central bore of the main body. The jarring tool further includes a central aperture extending along a length of the reciprocating hammer, an electrical connector extending from the upper connection and through the central aperture of the reciprocating hammer to at least the lower portion of the main body, and a release mechanism on the main body for releasing the reciprocating hammer from the first position and allowing reciprocating movement of the reciprocating hammer along the central bore. The electrical connector is configured to break when the reciprocating hammer is released from the first position.

A jarring tool includes a main body having a central bore extending therein, an upper connection at a proximal end of the main body for attaching the jarring tool to wireline or slickline, a lower portion at a distal end of main body, and a reciprocating hammer fixed at a first position within the central bore of the main body. The jarring tool further includes a central aperture extending along a length of the reciprocating hammer, an electrical connector extending from the upper connection and through the central aperture of the reciprocating hammer to at least the lower portion of the main body, and a release mechanism on the main body for releasing the reciprocating hammer from the first position and allowing reciprocating movement of the reciprocating hammer along the central bore. The electrical connector is configured to break when the reciprocating hammer is released from the first position.

An apparatus for applying a magnetic pressure to a work piece includes an inductor configured to be disposed in proximity to the work piece and a controller electrically connected to the inductor and configured to control a supply of electrical power in order to output a first voltage over a selected frequency range to determine a frequency that provides a maximum current or a frequency that provides a current within a selected range of the maximum current to the inductor.

An apparatus for applying a magnetic pressure to a work piece includes an inductor configured to be disposed in proximity to the work piece and a controller electrically connected to the inductor and configured to control a supply of electrical power in order to output a first voltage over a selected frequency range to determine a frequency that provides a maximum current or a frequency that provides a current within a selected range of the maximum current to the inductor.

An apparatus for applying a magnetic pressure to a work piece includes an inductor configured to be disposed in proximity to the work piece and a controller electrically connected to the inductor. The controller is configured to control a supply of electrical power in order to output a first voltage over a selected frequency range to determine a first frequency that provides a maximum current to the inductor or a second frequency that provides a current within a selected range of the maximum current to the inductor.