Study on the anti-wear performance of diamond impregnated drill bits

Abstract Diamond impregnated (DI) drill bits are widely used to drill the harder and more abrasive lithologies. Currently the wells have become increasingly more complex and longer, causing more stringent requirements for the abrasion resistance of DI mixes. In this work, new DI mixes outperforming the current benchmarks have been developed by investigating the abrasive wear behavior of DI mixes. It was found that the wear behavior of metal matrix composite (MMC) play a predominant role in DI mixes' wear resistance. MMC using spherical fused tungsten carbides exhibits much better abrasion resistance than conventional MMCs with irregularly shaped fused carbides and macrocrystalline carbides, which accordingly leads to a great increase in the wear resistance of DI mixes. The wear resistance of MMC can be further improved by using large-sized carbide particles. Finally, MMC's wear resistance was enhanced almost 5 times by tailoring the tungsten carbide blends. Besides the MMC's improvement, the wear resistance of DI mixes can be reinforced by increasing the concentration of diamond (or diamond numbers per unit area). However, a large amount of diamond in DI mixes may weaken the mixes' anti-wear performance due to the occurrence of diamond clusters after the infiltration. To solve this issue, the encapsulated diamond grits are recommended.