Numerical and Experimental Study on the Effects of Rheological Behavior of Drilling Fluid on the Performance of the Fluidic Down-the-Hole Hammer

Abstract

Summary In the field of oil and gas exploration, the fluidic down-the-hole (DTH) hammer has frequently been used to solve the challenges associated with hard rock drilling and excessive friction along the drillstring. Appropriate performance prediction for drilling tools is particularly important for the drilling operation. Previous experiments showed that the performance prediction scheme determined by the water was not accurate for fluidic DTH hammer driven by mud, which is a typical pseudoplastic power-law fluid. Based on the results, compared with water, the rheological behavior of the pseudoplastic power-law fluid can be significant for the flow behavior in the fluidic oscillator with a lower supply flow rate. However, for a normal or higher level of supply flow rate, because of the shear diluting effect of the pseudoplastic power-law fluid, the influence of rheology behavior of drilling mud on the performance of fluidic DTH hammer was not apparent. The temperature of the drilling fluid and barite weighting agent can also affect the performance of the fluidic DTH hammer by affecting the rheological properties of the drilling mud. In this paper, numerical simulation and experiments are used for qualitative discussion and conclusion verification, respectively.