Analysis of the effect of groove-type micro-texture on the lubrication performance of stator rubber in screw pumps under different well-site environments

Considering the coupled effects of geometric parameters of the micro-texture, arrangement inclination angle, spacing, shale oil viscosity, slip velocity, and other factors, a theoretical model of a multi-angle asymmetric groove-type micro-texture on the rubber surface of the screw pump stator was established based on dynamic pressure lubrication theory. Using the finite element method, the influence of the multi-inclination asymmetric groove-type micro-texture on the lubrication properties of the stator rubber surface in various shale oil well environments was analyzed, revealing the mechanism of multi-factor coupling on the kinetic characteristics of the pressure, velocity, and flow fields. To elucidate the influence mechanism of multi-factor coupling on the dynamics of the micro-texture’s pressure, velocity, and flow fields, nanosecond laser technology was employed to fabricate the rubber surface of the screw pump stator. Hardness tests and friction-wear experiments were performed on the fabricated stator rubber under various shale oil well environments, enabling a detailed investigation of the dynamic pressure lubrication properties of both the stator and rotor. The results demonstrate that the asymmetric grooved micro-texture significantly outperforms the symmetric micro-texture in enhancing the tribological performance between the stator and rotor. The asymmetric groove structure augments the hydrodynamic lubrication effect of the micro-texture, increases the oil film load-bearing capacity, and improves friction and drag reduction performance. As the alignment inclination angle increases, the maximum pressure on the woven oil film surface first increases and then decreases, peaking at an inclination angle of 60°. As shale fluid viscosity and slip velocity increase, the maximum stress on the wall surface of the asymmetric textured oil film rises, and the hydrodynamic pressure lubrication effect becomes more pronounced. As the arrangement spacing of the micro-texture increases, the friction coefficient exhibits a trend of initially decreasing and then increasing. .