A helical rotor intended to be arranged in a progressing cavity pump, said progressing cavity pump being capable of pumping a multiphase fluid from a fluid reserve, the helical rotor comprising at least one mixer capable of homogenizing the multiphase fluid located in said fluid reserve.

A stator for a progressive cavity pump or motor includes a stator housing having a longitudinal axis. In addition, the stator includes a stator insert of a material moulded within the housing. The stator housing includes an outer tube having an inner surface. The stator housing also includes a plurality of framework elements disposed on the inner surface of the outer tube. Further, the stator housing includes at least one recess in the inner surface of the outer tube. The conjunction of the framework elements and the at least one recess define a plurality of chambers receiving insert material therein whereby the insert material is mechanically fixed axially, radially and torsionally within the outer tube.

A drilling assembly includes a particle adjusting mechanism upstream of a positive displacement motor. The motor includes a metal stator, a metal rotor at least partially disposed within the metal stator, and a motor gap defined between the sealing line of the metal rotor and the lobes of the metal stator. The particle adjusting mechanism adjusts a solid particle condition of a media flowing therethrough into a treated condition in which any remaining solid particles will travel through the motor gap without widening the motor gap to a failure gap size that causes the metal rotor to lock up or to rotate inefficiently slow. The particle adjusting mechanism adjusts the solid particle condition by removing, reducing a size, reducing a dimension, deforming, modifying a shape, dissolving, or chemically reacting at least a portion of any solid particles contained in the media. The drilling assembly is suited for high temperature wellbores.

A drilling assembly includes a particle adjusting mechanism upstream of a positive displacement motor. The motor includes a metal stator, a metal rotor at least partially disposed within the metal stator, and a motor gap defined between the sealing line of the metal rotor and the lobes of the metal stator. The particle adjusting mechanism adjusts a solid particle condition of a media flowing therethrough into a treated condition in which any remaining solid particles will travel through the motor gap without widening the motor gap to a failure gap size that causes the metal rotor to lock up or to rotate inefficiently slow. The particle adjusting mechanism adjusts the solid particle condition by removing, reducing a size, reducing a dimension, deforming, modifying a shape, dissolving, or chemically reacting at least a portion of any solid particles contained in the media. The drilling assembly is suited for high temperature wellbores.