Cuttings transport behavior in directional drilling using computational fluid dynamics (CFD)

Abstract

As one of the most crucial concerns in hole cleaning and especially in directional drilling, cutting transport optimization eventuates in the reduction of drilling costs and increase in oil recovery. Cutting removal is, however, affected by different parameters including fluid flow rate, drill pipe rotation, cutting size and inclination which have to be considered simultaneously. In the current report, Liquid-Solid model is implemented to solve the governing equations in the Eulerian CFD framework. Results are compared with experimental data and successful validation with experimental data is achieved. On the basis of design of experiment algorithm, further simulations have been carried out to investigate the effect of the as mentioned key parameters on cutting transport behavior. Results show that hole inclinations between 45 and 60° are the most difficult angles in hole cleaning process. Moreover, increase in values of flow rate and drill pipe rotation will effectively improve the drag effects leading to superior cutting removal. Besides, it has been proven that cutting size affects cutting transport less than the other parameters. For industrial applications, an empirical correlation is developed for estimating cutting concentration. Buckingham-π theorem along with multi-variable regression technique is applied to establish the correlation.