Research on Three-wing Drill Bit and Simultaneous Casing Percussion Drilling Technology in Complex Strata

Aiming at the problems of hole drilling collapse, buried drilling, stuck drilling and others that are prone to occur in complex strata, based on the principle of simultaneous casing percussion drilling technology and the force analysis of drilling tools in the hole, a scalable three-wing drill bit simultaneous casing percussion drilling technology is proposed, which effectively optimizes the impact rotation process parameters of complex strata. By building a ground testing platform, the rock penetration ability and pipe protection follow-up ability of the three-wing drill bit are tested. The testing shows that the three-wing drill bit can smoothly drill into rocks with different hardnesses, and the main performance parameters of the drilling rig, such as torque, drilling pressure, rotation speed, and drilling speed, etc, will happen different fluctuations. It takes 5 hours and 28 minutes by adopting the conventional drilling method to penetrate the testing strata, with a maximum porosity rate of only 31.7%. In contrast, using a three-wing drill bit for conducting simultaneous casing percussion drilling can achieve a maximum porosity rate of up to 99.1% and a shortest time of only 2 hours and 21 minutes, and Its drilling efficiency is 233% of that of the conventional drilling method.