Development of bottom hole flow simulation experimental apparatus for air reverse circulation drilling

Bottom hole flow is the core flow field because it effects the efficiency of carrying cuttings of reverse circulation drilling. Bottom hole flow simulation experimental apparatus is the critical facilities and necessary means to carry out the corresponding research. Based on the formation characteristics of reverse circulation bottom hole flow field, the bottom hole flow simulation experimental apparatus of air reverse circulation drilling was designed, and the design process of main components was analyzed in detail. The pressure change with different cutting element, the bottom flow distribution in the condition of different combinations of the inner nozzles and the bottom nozzles and the effects between the different types inner tube inclination and the center hole pressure could be measured with experimental apparatus. Furthermore, different structural parameters influencing the bottom hole flow field were examined, and the results provided important theoretical and experimental basis for the structural optimization design of bottom hole tools for air reverse circulation drilling.