Analysis of air drilling hydraulics

Analysis of wellbore hydraulics is motivated by the need for improved understanding of this system so as to enhance air drilling operation. A viable wellbore hydraulics model is utilized as the basis for this study. Several important parameters that influence air drilling operations are analyzed, such as drill cutting size and size distribution, hole size changes, attrition, and particle shape. This work defines several areas that need special investigation and sheds light on several previously unanswered questions. The most salient findings are that hole size changes, cutting size and size distribution and particle shape affect the wellbore hydraulics very significantly. The analysis led to the evolution of a clear explanation for choking in air drilling.