Improving TC drill bit's efficiency and resistance to wear by graphene coating

Abstract

Displaying a two-dimensional pure crystal carbon structure, Graphene is the strongest, yet thinnest substance discovered by scientists. Coating tungsten carbide (TC) drill bits with graphene to evaluate the effect of graphene on the wear, as well as the rate of penetration of the drilling bit was examined in this research. Two evaluation approaches were employed: one with employing ANSYS Software and the second by employing atomic pressure chemical vapor deposition (APCVD synthesis) in the laboratory to produce a monolayer graphene coating. The simultaneous software-based and lab-based testing were performed to increase the credibility of the results and minimize the potential errors. Conducting the simulation using ANSYS, the maximum shear elastic strain, equivalent elastic strain, equivalent (von mises) stress, total deformation and maximum shear stress were investigated prior and after the graphene coating was applied on TC simulated bit. Total deformation was only slightly increased, while the maximum shear elastic strain was almost doubled, reflecting that the bit's wear was significantly reduced after the coating. Lab-based APCVD synthesis results showed 34% increase in compressive strength of the coated bit, in comparison to the uncoated one. The failure occurred for uncoated bit at 35 MPa, where the coated bit experienced failure at 46.9 MPa. The Von Mises stress test conducted on the coated and uncoated samples also indicated that this stress was 41% less for the coated bit, in comparison to the uncoated one. Finally, two small-scale drilling operations, one using a 1inch graphene-coated TC bit and the other using a 1inch non-coated TC bit, were performed on a granite block, to evaluate the performance of the graphene-coated bit in practice. In a chosen 120-min time frame, 27 consecutive holes could be drilled by the graphene-coated TC bit, while 19 consecutive holes could be drilled by the uncoated TC bit, in identical drilling conditions. This implies a 42% increase in ROP.