Effect of normal load and shearing velocity on the interface friction of organic shale – Proppant simulant

In the present study, experiments were conducted using an advanced micromechanical apparatus investigating the tribological behavior of interfaces between an organic shale against two different proppant simulants; one composed of Leighton Buzzard sand (LBS) and the other composed of glass beads. A negative correlation was observed between the coefficient of friction and the magnitude of normal load from organic shale-proppant interface shearing tests. At relatively low shearing velocities (0.2–0.4 mm/h) stick-slip shearing behavior was found to be more prominent, and the change of shearing velocity had insignificant influence on the coefficient of friction. Additional discussion is presented comparing these results from the present work with a previously studied inorganic shale.