Test and Simulation Research on Rock-Breaking of Laser-Assisted PDC Test Bits

Laser-assisted rock-breaking has the advantages of green and high efficiency, and is a technology that is expected to realize high-efficiency exploitation of oil and gas resources in deep, ultra-deep and hard-to-drill formations. A laser-assisted PDC (Polycrystaline Diamond Compact) test bit rock-breaking test device was successfully set up, and a comparative study between laser-assisted PDC test bit rock-breaking and PDC test bit rock-breaking test was carried out. The results show that: Under the conditions of a drill bit weight on bit of 10 kN and a rotation of 60 r/min, the rate of penetration was increased by 61% under the effect of the laser-assisted drilling. Using the finite element method, based on the rock HJC (Holmquist-Johnson-Cook) constitutive model to establish a simulation model of laser-assisted PDC test bit rock-breaking, and carry out the simulation study, the results show that laser irradiate of the rock surface can produces high temperature and pre-damage, so that the strength of the rock is weakened, which is conducive to the PDC drill bit to crush the rock; the with the laser-assisted action, in the drilling process the torque of the drill bit is reduced by 12.6%, the drilling displacement is increased by 16.22 mm, and the rate of penetration is increased by 85.92%. The research results can provide some guidance for the development and application of laser-assisted mechanical rock-breaking technology.