Experimental and performance analysis of reverse circulation reaming in horizontal directional drilling

To overcome the inefficient cuttings transportation performance of current large-diameter Horizontal Directional Drilling (HDD), the application of reverse circulation technology during the reaming process was studied resulting in the development of a novel reverse-circulation reamer. A prototype lab-scale reamer was developed in accordance with jet-pump design theory and project requirements. An experimental laboratory setup was developed to simulate the reverse circulation reaming process, through which parametric studies were performed to investigate the effects of various operating conditions on the reamer's performance and cuttings removal ability. The experimental results concluded that the reamer's non-cavitating performance kept constant with variations in operating conditions, while its anti-cavitation ability was reduced by increasing the primary flow rate or decreasing the suction pressure. Comparisons of non-cavitating experimental data with various theoretical correlations were conducted and Cunningham's model was founded to be most applicable. In addition, a critical rotatory speed was identified at which the reamer's ability to transport cuttings is most effective.