Tribological behaviors of quartz sand particles for hydraulic fracturing.

Particles are widely used as the fracturing proppant component. In order to better understand the mechanism of particles moving behavior for hydraulic fracturing, the frictional behavior at the contacts of grains has been investigated by using a self-developed testing device. The particles used in the tests are quartz sand particles, a kind of fracturing proppant particles. The in-situ observation results indicate that particle interaction process during sliding movement can be divided into four stages: initial slide stage, up slide stage, peak slide stage, down slide stage. Results also show that inter-particle friction properties in the sliding process are different when test conditions are changed. The friction mechanism and the influences of water absorption and surface layer peeling are discussed. [ABSTRACT FROM AUTHOR]