Design and application of novel hybrid drill bit for hard formation with strong abrasivity

To improve the rock breaking efficiency and the service life of polycrystalline diamond compact (PDC) bit in the hard formation with strong abrasivity, two novel PDC-impregnated diamond insert hybrid bits, which are composed of PDC cutters and impregnated diamond insert as cutting units, are designed and tested in the quartzite formation of a fault block in central Hebei Province. Field tests show that the rate of penetration (ROP) of 1^# novel bit is increased by 52.30% and that the bit footage is increased by 97.30% compared with the average value of roller bits used in the same well section.It is also found that the ROP of 2^# novel drill bit is increased by 30.85% and 32.30% and the bit footage is increased by 70.50% and 47.40% compared with the average value of roller bit and M1375D PDC bit. In conclusion, PDC-impregnated diamond insert hybrid drill bit greatly improves the drilling efficiency of hard formation with strong abrasivity and reduces the drilling cost.