Study on theFriction Behavior and Mechanism of DLCFilms in Waxy Oil Extraction Environment Based on Reactive MolecularDynamics

Diamond-like carbon (DLC) film is considered a highly promising coating for reducing friction and wear in oil and gas exploitation equipment, owing to its exceptional wear resistance and antifriction properties. Herein, the friction and wear behavior of the Fe–Fe model (conventional steel plunger pump barrel) and the DLC–Fe model (DLC-coated plunger pump barrel) in a waxy oil recovery environment was studied by Molecular dynamics (MD) simulation. The results show that the DLC film can inhibit the lattice evolution of the friction interface and reduce the shear deformation between the friction pairs and the weak interaction between the DLC film and the waxy crude oil system, ultimately reducing the friction and wear. In addition, as the environmental temperature rises, the friction of the Fe–Fe friction system continues to increase. Interestingly, the average friction of the DLC–Fe friction system after the increase in environmental temperature is smaller than its average friction at 298 K, implying that the DLC film has great potential in high-temperature oil extraction environments. This work may provide theoretical support for the practical engineering application of DLC films on the surface of oil well pump plungers.