An all-metal conical combined screw pump suitable for petroleum field includes: a stator, a rotor (2), a sleeve (3) and a sucker rod (4), wherein the internal threaded curved surface and the external threaded curved surface are both tapered The spiral structure and the taper are the same, and the end of the inner threaded surface and the outer threaded surface with the larger radial size is adjacent to the sucker rod; the all-metal conical combined screw pump further comprises an elastic telescopic component, wherein the elastic telescopic component comprises a movable part, a fixed part and a elastic part, the movable part is fixedly connected to the rotor, the fixed part is fixedly connected to the sucker rod, the movable part and the fixed part are slidly fitted in the up and down directions and can be To transmit torque to the sucker rod and the rotor, one end of the elastic member abuts against the movable part or the rotor, and the other end abuts against the fixed part or the sucker rod, the elastic member can Elastic contraction or elastic expansion along the sliding direction of the movable part.

A submersible pump assembly includes a seal section connected to a motor, the seal section having a housing with an outboard bearing at a housing pump end in radial supporting engagement with a drive shaft. An inboard bearing is also in the housing pump end, axially spaced from the outboard bearing, and in radial supporting engagement with the shaft. A barrier fluid chamber in the housing pump end contains a barrier fluid. A primary shaft seal is located within the barrier fluid chamber and seals the barrier fluid in the barrier fluid chamber from the motor lubricant. A secondary shaft seal is mounted in the barrier fluid chamber between the primary shaft seal and the outboard bearing. The secondary shaft seal seals the barrier fluid in the barrier fluid chamber from well fluid exterior of the housing pump end.

A stator for a progressive cavity pump may include a containment element with an inner surface and a casing. The casing may be arranged within the containment element, be generally isolated from the inner surface of the containment element, and define a stator cavity adapted for receiving a progressive cavity pump rotor and for accommodating substantially free rotation of the progressive cavity pump rotor therein.

A stator segment is provided for a helical gear device. The stator segment includes a stator tube and modular stator inserts. The stator tube has an inner profile with at least two internal sides that extend longitudinally along an interior of the stator tube. The modular stator inserts each have an outer profile that substantially matches and fits within the inner profile of the stator tube. The modular stator inserts also each have an interior helical profile that defines a central opening. The modular stator inserts are configured to be removably inserted longitudinally into the stator tube along the inner profile of the stator tube. The inner profile aligns the modular stator inserts to form a continuous helical chamber and prevents rotation of the modular stator inserts relative to the stator tube.

An apparatus and method for pressure testing a tubing string of a fluid production well, the tubing string being provided with a progressing cavity pump at a downhole end, which apparatus and method can be used to help determine whether the tubing string has failed or the pump has failed. The apparatus comprises a plug member connected to the rod string assembly that includes the pump rotor, such that the rod string assembly can be lowered to seat the plug member in a seat member within the tubing string above the pump, thus sealing off and isolating the pump from the rest of the tubing string, allowing pressure testing of the tubing string above the pump.

A method of forming a mud motor stator having a passage including a first end defining a first opening, a second end defining a second opening and an intermediate portion extending therebetween includes introducing a liner material into the passage at one of the first end and the second end of the stator, inserting a mandrel having a contoured surface into the passage through one of the first end and the second end of the stator, shifting one of the mandrel and the stator relative to the other of the mandrel and the stator, and flowing the liner material over the contoured surface of the mandrel from the one of the first and second ends toward the other of the first and second ends to form a liner on the inner surface of the passage.

A downhole drilling motor includes a motor housing having an inner bore and an outer surface. A power section includes a stator elastomer at least partially disposed within the inner bore of the motor housing. A bearing section includes an upper bearing at least partially disposed within the inner bore of the motor housing. The motor housing further includes an opening extending from the inner bore to the outer surface to provide a bypass fluid path for a fluid in the inner bore. The opening is disposed on the motor housing between a lower end of the stator elastomer and an upper end of the upper bearing. The bypass fluid path allows the downhole drilling motor to accommodate a higher flow rate of a fluid through the stator elastomer of the power section than through the upper bearing of the bearing section.

The invention concerns a method and an apparatus for operating a multi-phase pump which has a suction-side inlet (10) and a discharge-side outlet (20) and which pumps a multi-phase mixture charged with solids, comprising the following steps: a. pumping a multi-phase mixture into a discharge-side separation chamber (45), b. separating a gaseous phase from a liquid phase and a solid phase in the separation chamber (45), c. separating the liquid phase from the solid phase in the separation chamber (45), and d. supplying a portion of the liquid phase freed from the solid phase to the suction side.

Tapered stator designs are engineered in a positive displacement motor (PDM) power section to relieve stator stress concentrations at the lower (downhole) end of the power section in the presence of rotor tilt. A contoured stress relief (i.e. a taper) is provided in the stator to compensate for rotor tilt, where the taper is preferably more aggressive at the lower end of the stator near the bit.

A submersible pumping system has an electric motor, a rotary hydraulic pump driven by the electric motor, and a linear hydraulic pump that is configured to move a production fluid. The rotary hydraulic pump produces a pressurized working fluid that drives the linear hydraulic pump. In another aspect, a method is disclosed for controlling the temperature of an electric motor within a submersible pumping system disposed in a wellbore. The method includes the steps of circulating motor lubricant through a hydraulically driven production pump to reduce the temperature of the motor lubricant.