CFD Modelling of Multiphase Flow in Horizontal Pipe Annulus: Effect of Sweeping Pills on Drill Cuttings Removal

Abstract Effective hole cleaning plays a crucial role in drilling operations, especially with the ever-increasing number of deviated and horizontal wells. Sweeping pills are commonly pumped into the annulus to assist in cleaning of borehole from cuttings that have not been removed after the usual drilling fluid circulation. Hole cleaning becomes even more challenging with increasing inclination since the cuttings tend to settle down to the lower side of the annulus due to higher gravity effects. The sweeping performance of different pills has been studied by taking an advantage of computational fluid dynamics (CFD) approach and subsequently, confronting the results with the outcomes of experimental work conducted previously [SPE 201634]. Multiphase flow simulations have been carried out where varying combinations of pill type, cuttings diameter, and inner pipe rotation were tested to study their influences on the final cuttings recovery. The results obtained from CFD simulations are compared to the experimental ones with the aim of catching the consistencies and discrepancies in the observed flow behaviors. Furthermore, the insights gained emphasize the intricate interplay between inner pipe rotation and the effective suspension & transport of cuttings, shedding light on the nuances that can impact drilling efficiency. Furthermore, the study offers valuable recommendations for future research directions as well as field implications.