Abstract: The transport of cuttings bed in annulus bottom is bed-load sheared layer. Because of its high concentration and dispersed particles，the properties of cuttings bed are much differ-ent from continuous molecules and single particles. Based on the energy principle，the paper analyzes the influence of the factors of the friction and collision among cuttings particles and
the viscous resistance of ftuid(mud)on the collision times，moment exchange and dispersed forces. These conclusions are very important for studyuing and understanding the transport rule of bed-load cuttings.

Key words: Bed load transport of cuttings bed Horizontal wel