Methods and systems are provided to adaptively control a hydraulic fluid supply to supply a driving fluid for applying a driving force on a piston in a gas compressor, the driving force being cyclically reversed between a first direction and a second direction to cause the piston to reciprocate in strokes. During a first stroke of the piston, a speed of the piston, a temperature of the driving fluid, and a load pressure applied to the piston is monitored. Reversal of the driving force after the first stroke is controlled based on the speed, load pressure, and temperature.

Methods and systems are provided to adaptively control a hydraulic fluid supply to supply a driving fluid for applying a driving force on a piston in a gas compressor, the driving force being cyclically reversed between a first direction and a second direction to cause the piston to reciprocate in strokes. During a first stroke of the piston, a speed of the piston, a temperature of the driving fluid, and a load pressure applied to the piston is monitored. Reversal of the driving force after the first stroke is controlled based on the speed, load pressure, and temperature.

A lift apparatus and method for driving a downhole reciprocating pump is disclosed and includes a hydraulic cylinder having a piston and a hydraulic fluid port, the piston being coupled to a rod for driving the reciprocating pump, the piston being moveable between first and second ends of the cylinder in response to a flow of hydraulic fluid through the hydraulic fluid port. A variable displacement hydraulic pump is responsive to a displacement control signal to draw hydraulic fluid from a reservoir and to produce a controlled flow of hydraulic fluid at the outlet. The apparatus also includes a valve connected between the hydraulic fluid port and the reservoir, the valve being responsive to a valve control signal for controlling discharge of hydraulic fluid from the hydraulic fluid port of the cylinder back to the reservoir to facilitate movement of the piston through a downstroke away from the second end toward the first end of the cylinder. The apparatus further includes a first sensor located proximate the first end of the cylinder and operable to produce a first signal indicating a proximity of the piston to the first sensor, a second sensor located proximate the second end of the cylinder and operable to produce a second signal indicating a proximity of the piston to the second sensor, and a controller operably configured to generate the displacement control signal and the valve control signal in response to receiving the first signal and the second signal.

A lift apparatus and method for driving a downhole reciprocating pump is disclosed and includes a hydraulic cylinder having a piston and a hydraulic fluid port, the piston being coupled to a rod for driving the reciprocating pump, the piston being moveable between first and second ends of the cylinder in response to a flow of hydraulic fluid through the hydraulic fluid port. A variable displacement hydraulic pump is responsive to a displacement control signal to draw hydraulic fluid from a reservoir and to produce a controlled flow of hydraulic fluid at the outlet. The apparatus also includes a valve connected between the hydraulic fluid port and the reservoir, the valve being responsive to a valve control signal for controlling discharge of hydraulic fluid from the hydraulic fluid port of the cylinder back to the reservoir to facilitate movement of the piston through a downstroke away from the second end toward the first end of the cylinder. The apparatus further includes a first sensor located proximate the first end of the cylinder and operable to produce a first signal indicating a proximity of the piston to the first sensor, a second sensor located proximate the second end of the cylinder and operable to produce a second signal indicating a proximity of the piston to the second sensor, and a controller operably configured to generate the displacement control signal and the valve control signal in response to receiving the first signal and the second signal.

A hydraulic pumping system for use with a subterranean well can include an actuator with a displaceable actuator member, a magnet device that displaces with the actuator member, the magnet device including at least one permanent magnet positioned between low magnetic permeability elements, and a sensor that senses a magnetic flux propagated from the magnet device. The actuator can include a cylinder, and the sensor can include an outer tube, with materials of the cylinder and outer tube having substantially a same magnetic permeability. An enclosure can be positioned exterior to the cylinder, with the sensor being positioned at least partially in the enclosure. The enclosure can be configured to focus the magnet flux, so that it propagates to the sensor.

A hydraulic pumping system for use with a subterranean well can include an actuator with a displaceable actuator member, a magnet device that displaces with the actuator member, the magnet device including at least one permanent magnet positioned between low magnetic permeability elements, and a sensor that senses a magnetic flux propagated from the magnet device. The actuator can include a cylinder, and the sensor can include an outer tube, with materials of the cylinder and outer tube having substantially a same magnetic permeability. An enclosure can be positioned exterior to the cylinder, with the sensor being positioned at least partially in the enclosure. The enclosure can be configured to focus the magnet flux, so that it propagates to the sensor.

A fluid module includes a fluid rotor configured to rotatably drive or be driven by fluid produced from a wellbore. A first shaft is coupled to the fluid rotor. The first shaft is configured to rotate in unison with the fluid rotor. A thrust bearing module includes a thrust bearing rotor. A second shaft is coupled to the thrust bearing rotor. The second shaft is configured to rotate in unison with the thrust bearing rotor. The second shaft is coupled to the first shaft. An electric machine module includes an electric machine rotor. A third shaft is coupled to the electric machine rotor. A third shaft is configured to rotate in unison with the electric machine rotor. The third shaft is coupled to the second shaft. The third shaft is rotodynamically isolated from the first shaft and the second shaft.

A fluid module includes a fluid rotor configured to rotatably drive or be driven by fluid produced from a wellbore. A first shaft is coupled to the fluid rotor. The first shaft is configured to rotate in unison with the fluid rotor. A thrust bearing module includes a thrust bearing rotor. A second shaft is coupled to the thrust bearing rotor. The second shaft is configured to rotate in unison with the thrust bearing rotor. The second shaft is coupled to the first shaft. An electric machine module includes an electric machine rotor. A third shaft is coupled to the electric machine rotor. A third shaft is configured to rotate in unison with the electric machine rotor. The third shaft is coupled to the second shaft. The third shaft is rotodynamically isolated from the first shaft and the second shaft.

A device includes a rotor to rotate about a longitudinal axis, a magnetic bearing actuator, and an axial gap generator including a stator assembly adjacent to the rotor, the axial gap generator to generate an amount of power as a function of a gap spacing between the stator assembly and the rotor, the gap spacing parallel to the longitudinal axis, and the axial gap generator to supply the amount of power to a control coil of the magnetic bearing actuator.

A method of remanufacturing a fluid end block having a plurality of segments adapted to receive working fluid includes removing at least one damaged segment from the plurality of segments of the fluid end block. The method also includes providing at least one replacement segment at a location of the at least one damaged segment. The method further includes providing a seal between a first surface of the at least one replacement segment and a first surface of at least one adjacent segment of the plurality of segments. The method includes coupling the at least one replacement segment with the at least one adjacent segment to form a remanufactured fluid end block.