No abstract

No abstract

Despite intense studies for numerous scenarios, the potential of graphene as a lubricant additive for oil and gas drilling applications remains rarely investigated. This study investigates the influence of graphene on the tribological performance of three different aqueous drilling fluids: distilled water(DW)-, artificial seawater (KCl brine)-, and potassium chloride (KCl) polymer water-based muds. The presence of graphene resulted in remarkably improved lubricity and wear-resistance in different drilling fluids. Specifically, pure distilled water demonstrated an excessive coefficient of friction (COF) of 1.30, while its mixture with 1.25− 5.0 wt % graphene delivered COF values as low as 0.21, showing a reduction in friction by 70−85% and wear by 66−90%. As the graphene content increased in the KCl polymer water-based mud, the effectiveness of graphene in improving the lubricity and wearresistance attenuated consistently. For saturated KCl brine, graphene in the same concentration range reduced the COF from 0.62 to 0.25, representing 46−60% reduction in COF and 23−61% reduction in wear. For KCl polymer water-based mud, the addition of graphene in the same concentration range was able to reduce the COF from 0.49 to a minimum of 0.33, representing a reduction in COF and wear by 22−33 and 68−98%, respectively. The higher tribological improvement of the graphene/distilled water is attributed to the filling of the abrasive grooves with graphene sheets. On the other hand, the presence of small particles in KCl brineand KCl polymer water-based mud on the wear tracks prevents this phenomenon, causing lower tribological enhancements compared to distilled water. A possible explanation for the low friction and wear reduction is that the graphene, as a two-dimensional material, shears easily at the sliding contact interface. Furthermore, in the absence of abrasive micro−nanoparticles, the filling of the grooves with graphene sheets intensifies the tribological improvements.

No abstract