Experiment study on work-in parameters of combined high pressure jet and mechanical bit breaking rock

Using the experimental device of combined breaking rock,the experiment simulated the conditions at bottom of well in order to study the work-in parameters of combined breaking rock.,and then elicited the effect rule of four parameters,which were rock breaking means,distance between jet and bit,position of jet to bit and confined pressure.The result of experiment indicates: Combined working is superior to single bit working or single jet working;Breaking rock by jet behind bit is superior to the one ahead of bit;The confined pressure is inversely proportional to the effect of combined breaking rock, but the range is gradually weakened;The pressure of jet is proportional to the effect of combined breaking rock;when the space is more than 3 mm between jet and bit,it is inversely proportional to the effect of combined breaking.