A workover unit for lowering an irregularly shaped production string into a live well includes a traveling assembly and stationary assembly movable relative to each other. The traveling assembly may include a traveling static annular BOP configured to seal around the production string during the lowering. The traveling assembly may include a reciprocating riser connected to the traveling annular BOP. The traveling assembly may include traveling slips configured to grip the production string during the lowering. The stationary assembly may include a dynamic BOP configured to seal around the reciprocating riser during the lowering. The stationary assembly may include a reciprocating jack configured to lower the traveling assembly. The stationary assembly may include a lower static annular BOP configured to seal around the production string when the traveling assembly is moved relative to the production string.

An automated pipe tripping apparatus includes an outer frame and an inner frame. The inner frame includes a tripping slips and iron roughneck. The automated pipe tripping apparatus may, in concert with an elevator and drawworks, trip in a tubular string in a continuous motion. The tripping slips and iron roughneck, along with the inner frame, may travel vertically within the outer frame. The weight of the tubular string is transferred between the tripping slips and the elevator. The iron roughneck may make up or break out threaded connections between tubular segments, the upper tubular segment supported by the elevator and the lower by the tripping slips. An automated pipe handling apparatus may remove or supply sections of pipe from or to the elevator. A control system may control both the automated pipe tripping apparatus and the elevator and drawworks.

An automated pipe tripping apparatus includes an outer frame and an inner frame. The inner frame includes a tripping slips and iron roughneck. The automated pipe tripping apparatus may, in concert with an elevator and drawworks, trip in a tubular string in a continuous motion. The tripping slips and iron roughneck, along with the inner frame, may travel vertically within the outer frame. The weight of the tubular string is transferred between the tripping slips and the elevator. The iron roughneck may make up or break out threaded connections between tubular segments, the upper tubular segment supported by the elevator and the lower by the tripping slips. An automated pipe handling apparatus may remove or supply sections of pipe from or to the elevator. A control system may control both the automated pipe tripping apparatus and the elevator and drawworks.

A ball transfer mechanism for a harmonic drive and linear piston motor is disclosed. The ball transfer mechanism includes a spherical ball and a cylindrical seat portion. The seat portion defines a hemispherical shaped recess with a contour for receiving the ball. The ball transfer mechanism is in an exterior wall of a housing for converting rotary motion to linear motion, driving a linear piston motor. The harmonic drive drives a rotor of the linear piston motor. The harmonic drive includes a hollow cylindrical coupler portion engaging a rotor portion for transferring torque to the rotor portion. Transfer mechanisms disposed along a housing wall of the linear piston motor engage the coupler portion. The coupler portion includes harmonic cam grooves for receiving spherical balls in the ball transfer mechanism that drives rotational motion in the rotor in response to axially linear movement of the piston assembly.

A ball transfer mechanism for a harmonic drive and linear piston motor is disclosed. The ball transfer mechanism includes a spherical ball and a cylindrical seat portion. The seat portion defines a hemispherical shaped recess with a contour for receiving the ball. The ball transfer mechanism is in an exterior wall of a housing for converting rotary motion to linear motion, driving a linear piston motor. The harmonic drive drives a rotor of the linear piston motor. The harmonic drive includes a hollow cylindrical coupler portion engaging a rotor portion for transferring torque to the rotor portion. Transfer mechanisms disposed along a housing wall of the linear piston motor engage the coupler portion. The coupler portion includes harmonic cam grooves for receiving spherical balls in the ball transfer mechanism that drives rotational motion in the rotor in response to axially linear movement of the piston assembly.

A workover unit for lowering an irregularly shaped production string into a live well includes a traveling assembly and stationary assembly movable relative to each other. The traveling assembly may include a traveling static annular BOP configured to seal around the production string during the lowering. The traveling assembly may include a reciprocating riser connected to the traveling annular BOP. The traveling assembly may include traveling slips configured to grip the production string during the lowering. The stationary assembly may include a dynamic BOP configured to seal around the reciprocating riser during the lowering. The stationary assembly may include a reciprocating jack configured to lower the traveling assembly. The stationary assembly may include a lower static annular BOP configured to seal around the production string when the traveling assembly is moved relative to the production string.

Systems and methods for installing pipe underground are disclosed. The system includes a pneumatic rammer configured to provide a percussive force to a section of pipe. The system also includes a main jacking frame coupled to the pneumatic rammer, the main jacking frame including a surface for contacting the section of pipe. The system also includes one or more hydraulic jacks coupled to the main jacking frame and configured to provide a hydraulic force to the section of pipe. The system also includes a set of tracks coupled to the main jacking frame, the set of tracks permitting the main jacking frame to slide in a longitudinal direction. An independently displaceable soil-clearing system can be included to clear dirt coming inside the pipe during the installation and add extra jacking force as needed.

Systems and methods for installing pipe underground are disclosed. The system includes a pneumatic rammer configured to provide a percussive force to a section of pipe. The system also includes a main jacking frame coupled to the pneumatic rammer, the main jacking frame including a surface for contacting the section of pipe. The system also includes one or more hydraulic jacks coupled to the main jacking frame and configured to provide a hydraulic force to the section of pipe. The system also includes a set of tracks coupled to the main jacking frame, the set of tracks permitting the main jacking frame to slide in a longitudinal direction. An independently displaceable soil-clearing system can be included to clear dirt coming inside the pipe during the installation and add extra jacking force as needed.

A ball transfer mechanism for a harmonic drive and linear piston motor is disclosed. The ball transfer mechanism includes a spherical ball and a cylindrical seat portion. The seat portion defines a hemispherical shaped recess with a contour for receiving the ball. The ball transfer mechanism is in an exterior wall of a housing for converting rotary motion to linear motion, driving a linear piston motor. The harmonic drive drives a rotor of the linear piston motor. The harmonic drive includes a hollow cylindrical coupler portion engaging a rotor portion for transferring torque to the rotor portion. Transfer mechanisms disposed along a housing wall of the linear piston motor engage the coupler portion. The coupler portion includes harmonic cam grooves for receiving spherical balls in the ball transfer mechanism that drives rotational motion in the rotor in response to axially linear movement of the piston assembly.

A ball transfer mechanism for a harmonic drive and linear piston motor is disclosed. The ball transfer mechanism includes a spherical ball and a cylindrical seat portion. The seat portion defines a hemispherical shaped recess with a contour for receiving the ball. The ball transfer mechanism is in an exterior wall of a housing for converting rotary motion to linear motion, driving a linear piston motor. The harmonic drive drives a rotor of the linear piston motor. The harmonic drive includes a hollow cylindrical coupler portion engaging a rotor portion for transferring torque to the rotor portion. Transfer mechanisms disposed along a housing wall of the linear piston motor engage the coupler portion. The coupler portion includes harmonic cam grooves for receiving spherical balls in the ball transfer mechanism that drives rotational motion in the rotor in response to axially linear movement of the piston assembly.