Simulation of penetration rate of air percussion drilling bit

It is difficult to calculate the penetration rate (ROP) of percussion drilling.According to the dynamic model,the geometric structure model and the theory of roller cone bit,the mathematical models for hammer bit and true bottom hole as well as the mathematical model between tooth and rock of hammer bit were established.Hence,the penetration rate of the percussion drilling bit can be predicted by simulation.Field tests show that the models are reliable and the simulated results are coincident with the data of field.The research is helpful to design hammer bit and optimize drilling parameters.