Wellbore dynamic surge pressure while tripping a drill pipe in slim hole drilling

Dynamic surge pressure is the main factor that influences the stability of drilling hole while tripping a drill pipe in geologic drilling.In order to study the influence factors of the dynamic surge pressure,through the regressive analysis and probability statistics of russian scholar's experimental data,the paper demonstrates that the surge pressure has direct ratio relations with velocity of pipe trip and the depth of borehole and is also affected by the factors such as drilling fluid property,hole structure,and so on,and the formula of the surge pressure is finally given.The results of engineering cases prove that the formula is reliable,and the precision of prediction can meet engineering need.