摘要：The migration of the cuttings bed directly in- fluences the extension of large displacement wellsand construction safety. In highly inclined wells, cuttings are transported out of the hole mainly by rolling or lifting. Based on force analysis on a cut- tings particle, a model of predicting the critical cut- ting transport velocity had been developed. Some presumption by investigators had been modified. The hydraulic drag force was not assumed to act on the center of the particle, and the starting position of boundary layer velocity distribution had been mod-ified to be 1/4 of particle diameter below the bed surface. A helical flow velocity distribution in ec- centric annulus had been employed, which makes the model able to analyze the effects of drill pipe rotation and eccentricity. The prediction results showed good agreement with the experimental data and the prediction accuracy was improved. The model had been used to analyze the hydraulic data of a well, and the prediction results coincided with the incident record of the well, which proved that the model can be a good tool to analyze the hole clean- ing behavior in drilling practice. Better understand- ing of the near-bed interaction mechanism between the particle and drilling fluid will for sure favor the further research of cutting transport in inclined wells.
