Analysis and Application of a New Hybrid Drill Bit for Use in Hard Rocks

Abstract

A polycrystalline diamond compact (PDC) bit has advantages, such as a fast drilling rate and long drilling footage, but its abrasive resistance is low. Although an impregnated diamond bit has a high abrasive resistance, the corresponding rate of penetration (ROP) is low. In view of the difficulties of rock breaking in hard rocks and the characteristics of each cutter type, it is necessary to design a new hybrid drill bit with multiple cutting functions. Through laboratory experimentation and analysis, this study investigated a conical PDC cutter with a strong penetration capacity, abrasive resistance and impact resistance, and developed a new diamond-impregnated block embedded with natural diamonds, with consideration of its matrix formulation and diamond grades, sizes, and concentrations. Moreover, this research optimized the crown shape, blades, cutters' position and number with a reinforced hydraulic structure. The combination of three cutters with different structures enables the drill bit to adapt to drilling in hard rocks and greatly improves the rock-breaking efficiency and service life of the drill bit. The drilling test was conducted of the well Jingu 1-1HF in the Jinshan gas field and drill bit demonstrated excellent performance.