The Study On Prime-sub Alternating Water Ways Of High-matrix Impregnated Diamond Bit

Drilling efficiency and service life of diamond drill bit are two important indicators for the bit quality. The previous studies on diamond drill bit were more focusing on improving the drilling efficiency. But nowadays since the drilling depths increase, the bit service life is more important in the wire line core drilling, which takes the major position. Therefore, in recent years, in order to meet drilling market demand, many scholars and experts at home and abroad are beginning to improve the life of the drill bit through changing matrix material, process performance and lip surface structure. However, these traditional methods have limitation in improving the bit life and can not meet the needs of deep-hole drilling. Some experts and scholars break the traditional ideas and try to design high-matrix impregnated diamond bit, which extend the service life by increasing the depth of matrix. In the field drilling, although the life of high-matrix impregnated diamond drill bit has been further improved compared with traditional methods, it did not achieve the desired effect. In comprehensive analysis, there are three key technologies ---the matrix strength, the radius retention ability and water way, and these factors determine the bit life. Consequently, to make better use of the high-matrix diamond bit, the study on these key aspects should be strengthened.According to the problems of high-matrix impregnated diamond bit, this paper is aimed at designing a prime-sub alternating water ways of high-matrix impregnated diamond bit on the basis of multilayer-water way impregnated diamond bit. The bit is designed with three layers of prime-sub alternating water ways. At the beginning of drilling, the initial main water ways and the subsidiary water ways of the pad area are working, with the wear of work layer, the height of the initial main water ways and the subsidiary water ways gradually reduce. Hidden water ways expose and become the main water ways to continue working when the initial subsidiary water ways are completely worn out and the initial main water ways become the reference water ways of the next link. In the drilling process, primary water ways and reference water ways take turns to work until the matrix disappeared.