Cuttings transport implications for drill string design: a study with computational fluid dynamics

Abstract

Modern drilling programs require a variety of drilling equipment over a variety of well paths. Changes in equipment and parameters greatly affect the process of cuttings transport in the wellbore. While extensive experimental work has explored a multitude of drilling parameters, a firm methodology for using computational fluid dynamics to model this process has not been established. Moreover, computational models more easily compare different drilling geometries than experimental apparatuses that require significant equipment exchange. This thesis first establishes a methodology for utilizing computational fluid dynamics to model cuttings transport in a drilling annulus. The results establish qualitatively comparable results to prior experimental work. Therefore, the tool is made useful by isolating and studying the effects of changing parameters. The second part of the thesis consists of a parameter study to determine effects of drill pipe rotation, drilling fluid velocity, drill pipe eccentricity, wellbore inclination, and rate of penetration on cuttings accumulation over different drill pipe and borehole sizes. Results include both individual parameter effects as well as combined effects of the parameters in a single scenario, some of which suggest more complex mechanisms of cuttings transport than previously postulated.