An oil field pump is installed within a pipe that connects to an oil field, and feeds accumulated extraction oil in a predetermined direction, the oil filed pump including a rotor with an internal flow path for the extraction oil, a stator installed on the outer circumference of the rotor, a thrust bearing that supports the axial weight of the rotor and the stator, a supply pipe that supplies a portion of the extraction oil in the flow path to the thrust bearing, and a filter that is installed at further upstream on the flow path than the supply pipe along the flow direction of the extraction oil, and traps foreign matter.

A seal section of a submersible well pump assembly has an expandable and contractible bag surrounded by a pressure equalizing chamber. A motor lubricant communication path communicates motor lubricant the bag interior. A well fluid port admits well fluid into the pressure equalizing chamber. A gas vent passage leads from the pressure equalizing chamber to the exterior of the enclosure. At least one membrane in the gas vent passage allows gas contained in the well fluid in the pressure equalizing chamber to vent. The membrane blocks liquid from flowing through the gas vent passage into and out of the pressure equalizing chamber.

A seal section of a submersible well pump assembly has an expandable and contractible bag surrounded by a pressure equalizing chamber. A motor lubricant communication path communicates motor lubricant the bag interior. A well fluid port admits well fluid into the pressure equalizing chamber. A gas vent passage leads from the pressure equalizing chamber to the exterior of the enclosure. At least one membrane in the gas vent passage allows gas contained in the well fluid in the pressure equalizing chamber to vent. The membrane blocks liquid from flowing through the gas vent passage into and out of the pressure equalizing chamber.

Systems and methods for controlling downhole linear motors to minimize connections to surface equipment. In one embodiment, an ESP system is coupled by a power cable to equipment at the surface of a well. The ESP system includes a linear motor and a reciprocating pump. The motor has a set of position sensors that sense the position of a mover in the motor. Combining circuitry (E.G., XOR gate) combines the outputs of the position sensors into a single composite signal in which signal components corresponding to the position sensors are indistinguishable. A single channel carries the composite signal from the ESP system to the surface equipment. A control system determines a starting position of the motor and determines its subsequent position based on transitions in the composite signal. The motor is then operated based on the position determined from the composite signal.

Systems and methods for controlling downhole linear motors to minimize connections to surface equipment. In one embodiment, an ESP system is coupled by a power cable to equipment at the surface of a well. The ESP system includes a linear motor and a reciprocating pump. The motor has a set of position sensors that sense the position of a mover in the motor. Combining circuitry (E.G., XOR gate) combines the outputs of the position sensors into a single composite signal in which signal components corresponding to the position sensors are indistinguishable. A single channel carries the composite signal from the ESP system to the surface equipment. A control system determines a starting position of the motor and determines its subsequent position based on transitions in the composite signal. The motor is then operated based on the position determined from the composite signal.

Embodiments are disclosed for the control of downhole pumping systems that can perform a controlled draining operation of the downhole pumping system in the event of an interruption of a drive. Such embodiments include a zero power factor control, a motor braking, and a pumping down operation. The apparatus and the methods disclosed can include an independent piece of equipment interlocked with a variable speed drive, and installed at the primary or secondary of the step-up transformer where used. However, integration within other pieces of equipment, in particular the variable speed drive, and its control by the latter is also contemplated. Also disclosed is a transformer having a tap changer that includes a plurality of taps and contacts including shorting contacts, open contacts and auxiliary contacts.

Embodiments are disclosed for the control of downhole pumping systems that can perform a controlled draining operation of the downhole pumping system in the event of an interruption of a drive. Such embodiments include a zero power factor control, a motor braking, and a pumping down operation. The apparatus and the methods disclosed can include an independent piece of equipment interlocked with a variable speed drive, and installed at the primary or secondary of the step-up transformer where used. However, integration within other pieces of equipment, in particular the variable speed drive, and its control by the latter is also contemplated. Also disclosed is a transformer having a tap changer that includes a plurality of taps and contacts including shorting contacts, open contacts and auxiliary contacts.

A hydraulic fracturing spread system has modular high-pressure fracturing fluid manifold assemblies which couple to form a large trunk line for collecting and conveying high pressure fracturing fluid toward the well bore. Oil-hydraulic intensifier pump units integrated with the modular manifold assemblies increase the fracturing fluid pressure into the trunk line. The manifold assemblies may be configured differently from one to the other and coupleable horizontally and/or vertically.

A hydraulic fracturing spread system has modular high-pressure fracturing fluid manifold assemblies which couple to form a large trunk line for collecting and conveying high pressure fracturing fluid toward the well bore. Oil-hydraulic intensifier pump units integrated with the modular manifold assemblies increase the fracturing fluid pressure into the trunk line. The manifold assemblies may be configured differently from one to the other and coupleable horizontally and/or vertically.

A variable frequency drive system and a method of controlling a pump driven by a motor with the pump in fluid communication with a fluid system is provided. The method includes monitoring a pressure in the fluid system, monitoring and adjusting an operating frequency of the motor to maintain the pressure at a pressure set point, and, based on the monitored operating frequency, causing the pump to temporarily boost the pressure in the fluid system to a temporary boost set point for a first time period. The method also includes determining whether the temporarily boosted pressure in the fluid system stays above the pressure set point for a second time period and causing the pump to enter a sleep mode when the temporarily boosted pressure stays above the pressure set point through the second time period.