Abstract: A method for producing gas from a well with low pressure involves running a bottom hole pressure test to graph a P-Q curve. The operator computes a frictional pressure drop due to friction of the gas flowing through the production tubing to the surface. A packer is set above perforations in the well. A screw pump is selected that has a capacity equal to the sum of the frictional pressure drop plus a desired wellhead pressure. The screw pump has a flow rate capacity determined from the P-Q curve. The operator may vary the frequency of a downhole motor to achieve the desired wellhead pressure.

Abstract: A method for producing gas from a well with low pressure involves running a bottom hole pressure test to graph a P-Q curve. The operator computes a frictional pressure drop due to friction of the gas flowing through the production tubing to the surface. A packer is set above perforations in the well. A screw pump is selected that has a capacity equal to the sum of the frictional pressure drop plus a desired wellhead pressure. The screw pump has a flow rate capacity determined from the P-Q curve. The operator may vary the frequency of a downhole motor to achieve the desired wellhead pressure.

Abstract: A centrifugal pump has impellers for pumping low flow, high viscous materials. The impellers have high exit angles greater than 30 degrees and preferably greater than 50 degrees. The impellers and diffusers have specific geometry that varies with viscosity. The pump has zones of impellers and diffusers with the exit angles and geometry in the zones differing from the other zones. The exit angles decrease and geometry varies in a downstream direction to account for a lower viscosity occurring due to heat being generated in the pump. One design employs small diameter impellers and high rotational speeds.

Abstract: A method for producing gas from a well with low pressure involves running a bottom hole pressure test to graph a P-Q curve. The operator computes a frictional pressure drop due to friction of the gas flowing through the production tubing to the surface. A packer is set above perforations in the well. A screw pump is selected that has a capacity equal to the sum of the frictional pressure drop plus a desired wellhead pressure. The screw pump has a flow rate capacity determined from the P-Q curve. The operator may vary the frequency of a downhole motor to achieve the desired wellhead pressure.

Abstract: A centrifugal pump has impellers for pumping low flow, high viscous materials. The impellers have high exit angles greater than 30 degrees and preferably greater than 50 degrees. The impellers and diffusers have specific geometry that varies with viscosity. The pump has zones of impellers and diffusers with the exit angles and geometry in the zones differing from the other zones. The exit angles decrease and geometry varies in a downstream direction to account for a lower viscosity occurring due to heat being generated in the pump. One design employs small diameter impellers and high rotational speeds.

Abstract: A method and system for downhole treatment and pumping of well fluids enhances the pumping of viscous fluids to the surface. The first step is to separate the oil and water from the well fluid and then channel the oil to a chamber that encloses the motor. The heat from the motor will increase the heat of the crude oil flowing past the motor, thereby lowering the viscosity of the crude oil. The water flows separately past the motor in another passageway, and remixes with the oil. After the oil and water recombine, the treated well fluid has a lower viscosity, and the fluid is then pumped to the surface more efficiently than without treating the oil.

Abstract: A centrifugal pump has impellers for pumping low flow, high viscous materials. The impellers have high exit angles greater than 30 degrees and preferably greater than 50 degrees. The impellers and diffusers have specific geometry that varies with viscosity. The pump has zones of impellers and diffusers with the exit angles and geometry in the zones differing from the other zones. The exit angles decrease and geometry varies in a downstream direction to account for a lower viscosity occurring due to heat being generated in the pump. One design employs small diameter impellers and high rotational speeds.

Abstract: A method and system for downhole treatment and pumping of well fluids enhances the pumping of viscous fluids to the surface. The first step is to separate the oil and water from the well fluid and then channel the oil to a chamber that encloses the motor. The heat from the motor will increase the heat of the crude oil flowing past the motor, thereby lowering the viscosity of the crude oil. The water flows separately past the motor in another passageway, and remixes with the oil. After the oil and water recombine, the treated well fluid has a lower viscosity, and the fluid is then pumped to the surface more efficiently than without treating the oil.

Abstract: A centrifugal pump is lowered into a well and retrieved from the well by means of its power cable. The power cable has a single conductor. The pump has a downhole electrical motor which is three-phase. Single-phase AC power will be supplied from the surface down the conductor, with the return being the casing. A phase converter converts the single-phase AC power to three-phase AC power downhole for driving the pump motor.

Abstract: An electric submersible pump system has a pressure monitoring device for monitoring the pressure down the hole. The pressure monitoring device has a pressure transducer whose resistance varies with the pressure. The pressure transducer is connected to ground and is supplied with a DC current that is superimposed on the AC power cable. A temperature switch is connected between the pressure transducer and the motor winding. The temperature switch is normally open, and closes when it reaches a selected temperature. The temperature is selected to be above the ambient temperature in the well and below the temperature that occurs when the motor is operating and fully warmed up. The temperature switch isolates the windings from ground when the motor is shut off and cooled down. This enables the motor winding and power cable to be checked for insulation resistance.

Abstract: A steam generator is located downhole in a well for generating steam to cause viscous crudes to flow out adjacent walls. A packer is mounted above the steam generator. A connector box is located between the packer and the steam generator. An electrical cable extends alongside tubing into the well and into a window in the tubing located just above the packer. The cable extends through a passage in the packer and into the connector box. Feedthrough connectors in the connector box connect the power cable with lead wires extending upward from the steam generator. Heat pipes extend from the connector box upward through the packer. The heat pipes contain gas which circulates to aid in dissipating heat from the connector box.

Abstract: A steam generator is located downhole in a well for generating steam to cause viscous crudes to flow out adjacent wells. A packer is mounted above the steam generator. A connector box is located between the packer and the steam generator. An electrical cable extends alongside tubing into the well and into a window in the tubing located just above the packer. The cable extends through a passage in the packer and into the connector box. Feedthrough connectors in the connector box connect the power cable with lead wires extending upward from the steam generator. Cooling fluid passages in the packer allow circulation of cooling fluid from the surface to cool the components. The packer is hydraulically set by water supplied to the cooling fluid passages. A disk ruptures after the packer has been set to enable circulation of the cooling fluid.

Abstract: A well pump assembly has a tube extending into the well for delivering water to a point below the pump to reduce the viscosity of the oil being pumped. The downhole motor that drives the pump is surrounded by a jacket. The tube that delivers the water extends to a point below the jacket to a cross-over member mounted to the lower end of the jacket, which directs the water upward and inward. The cross-over member also has passages that directs the production fluid upward and outward.

Abstract: A pump differential pressure monitor system enables both discharge and intake pressure to be monitored at the surface of a centrifugal well pump. This system includes a tubular sub mounted between the pump and the tubing. A receptacle is located inside the sub. A bypass passage extends past the receptacle for directing fluid discharged from the pump past the receptacle and into the tubing. A pair of pressure sensors are lowered on conductor cable and located inside the receptacle. One of the sensors communicates with the bypass passage to monitor discharge pressure. A port extends from the receptacle to the exterior of the sub and communicates fluid to the other pressure sensor for monitoring intake pressure.

Abstract: A low volume submersible pump assembly has features to stabilize the operation. The pump assembly includes a centrifugal pump driven by a submerged electrical motor. The centrifugal pump has an impeller configuration that is designed for high specific head, but potentially unstable operation. At the design speed, the pump potentially could deliver an indeterminate flow rate for a given head. Also, at the design speed, the design flow rate will yield a design head that is very close to the maximum head at zero flow. The pump has the characteristic of requiring a significant increase in torque to produce higher flow rates. To stabilize the potentially unstable pump, a variable speed drive varies the speed of the motor to maintain constant torque. Maintaining a constant torque allows a considerable variance in head with only a small variance in flow rate resulting.

Abstract: A centrifugal submersible pump has wear resistant features to resist erosion due to sand laden fluid from a well. The pump has diffusers and impellers located within a housing. Wear resistant inserts are secured to the diffusers and impellers. The inserts include inserts with cylindrical surfaces for radial support and sealing, and inserts with flat transverse surfaces for thrust. The inserts are preferably formed of tungsten carbide and are harder than the material of the impellers and the diffusers.

Abstract: An electric motor has features for preventing the bearings from rotating. The motor has a stator mounted in a housing. A rotor is rotated within the stator. The rotor is divided into rotor sections, with bearings spaced between. Each bearing has an outer portion that contains outwardly biased pins. The pins engage slot gaps formed in the stator laminations.

Abstract: An electrical coupling particularly for submersible pumps serves as a barrier between high and low pressure zones and allows electrical cables to be connected through it. The coupling includes a jacket mounted in a housing. The jacket has at least one tapered hole extending through it. A conductor rod is bonded to a dielectric sheath and inserted into the hole. The sheath is compressed in the hole to provide sealing. The sheath is preferably of glass bonded mica.

Abstract: Low voltage starting of a three-phase submersible pump motor in a shallow well is achieved by employing a high-impedance transformer for supplying the three-phase power to the motor. Upon starting, the normally heavy current drawn by the motor results in a voltage drop through the high-impedance transformer sufficient to substantially lower the voltage across the motor and hence the starting current. In the absence of limiting the starting current, abnormally high starting torques will be produced on the motor shaft resulting in mechanical fatigue and eventually shaft breakage.

Abstract: Electrical conductors having suitable combinations of coatings and coverings are disclosed which have the ability to inhibit low molecular weight hydrocarbon well fluids when under pressure and withstand high proportions of gassy hydrocarbons under pressure without undergoing rupture failure.