Investigation on horizontal and deviated wellbore cleanout by hole cleaning device using CFD approach

The application of the hole cleaning device in downhole is a new technology for removing cuttings bed, and it can increase the efficiency of cuttings transport. This paper mainly studies the effects of the helical angle and the rotational speed of the blade of the hole cleaning device on the swirl strength of decaying swirl flow and drilled cuttings deposition behavior. A three-dimensional computational fluid dynamics (CFD) model is established using the Eulerian-Eulerian two-fluid model, Realizable k-epsilon turbulence model, and Sliding Mesh technique for simulating the two-phase fluid flow. The results have been compared with available data in the literature, and a good agreement is found. In order to understand the decay behavior of the swirl flow along the flow direction, the initial swirl strength, the swirl number, and the decay rate of swirl are analyzed in detail in single phase. The effects of the swirl flow induced by the blade on the deposition behavior of drilled cuttings under different rotational speed and helical angle are studied. A new deposition index is used to evaluate the effective distance and hole cleaning efficiency of the swirl flow under various parameters. It has been observed that using the hole cleaning device can improve the hole cleaning performance. The research results of this paper is instructive to the design of the hole cleaning device using in the drilling engineering.