In the relentless pursuit of efficiency and longevity in drilling operations, researchers have turned their attention to the often-overlooked factor of cutter wear. A recent study led by Maosheng Cai from the School of Petroleum Engineering at Yangtze University, Wuhan, China, has shed new light on how wear affects the performance of polycrystalline diamond composite (PDC) cutters. The findings, published in ‘Jin’gangshi yu moliao moju gongcheng’ (translated to ‘Rock and Mineral Engineering’), could revolutionize the way we approach drilling in the energy sector.
Cai and his team delved into the intricate dynamics of cutter wear, focusing on how it influences cutting load and heat generation. Using a 3D dynamic rotational simulation model, they analyzed the stress states and temperature rises of cutting teeth under various conditions. The results were eye-opening. “We found that as the wear height increases, the cutting load and temperature rise significantly,” Cai explained. “This not only affects the cutter’s performance but also accelerates its failure.”
The study revealed that the cutting load increases with wear height up to a certain point, after which it slightly decreases. However, the axial force on worn teeth is consistently higher than on unworn teeth, peaking at a wear height of 1.5 mm. This increased load can lead to more complex and variable forces on the cutter, heightening the risk of fatigue failure. “The force on a cutter with excessive wear is more complex and variable, increasing the risk of fatigue failure,” Cai noted.
The research also highlighted the impact of cutting depth and front inclination angle on cutting load. As the cutting depth increases, so does the tangential and axial force, with the fluctuation becoming more intense. Similarly, a higher front inclination angle results in increased cutting load, with a 28% increase in tangential force and a 32% increase in axial force when the angle is raised from 10° to 20°. However, the study suggests that a front angle of 15°−20° is optimal for prolonging the service life of cutting teeth.
One of the most significant findings was the temperature rise in worn teeth. The temperature on the side away from the central axis is higher due to differing linear speeds, and the high-temperature area is concentrated in the cutting-cutter contact area. This temperature rise is much higher in worn teeth, increasing the risk of thermal wear and accelerating the cutter’s failure. “The temperature rise of worn teeth is much higher than that of unworn teeth, and the temperature rise increases with the increase of wear degree,” Cai stated.
The implications of this research are profound for the energy sector. By understanding the dynamics of cutter wear, drilling operations can be optimized to reduce the risk of cutter failure and extend the service life of cutting teeth. This could lead to significant cost savings and increased efficiency in drilling operations. The study suggests that placing auxiliary cutting units behind the main cutting unit and controlling the front angle can effectively reduce the load on the main cutting gear and prolong its service life.
As the energy sector continues to evolve, the insights gained from this research will be invaluable in shaping future developments. By focusing on the often-overlooked factor of cutter wear, researchers have opened up new avenues for improving drilling efficiency and longevity. The findings published in ‘Rock and Mineral Engineering’ serve as a testament to the importance of understanding the intricate dynamics of cutter wear and its impact on drilling operations.
