Flow of power-law fluid in a partially blocked eccentric annulus

摘要

One of the most significant benefits of directional drilling is the increase in well productivity using multiple wells from a single vertical wellbore. During directional drilling, the drill pipe rests on the low-side of the annulus because of gravity. Moreover, cuttings beds form on the low-side of the annulus. Cuttings beds are undesirable because they increase hydraulic resistance of the annulus and consequently, the bottom hole pressure and Equivalent Circulating Density (ECD). Beside this, the annular flow becomes complicated. As a result, predicting relevant hydraulic characteristics of the annulus (friction pressure gradient and wall shear stresses acting on the bed and wellbore) becomes challenging due to lack of accurate hydraulic models that account for bed formation in eccentric annulus.