Drilling time will be lasted and lateral force on casing exerted by drill pipe will increase in case of drilling deep well , ultradeep well , high inclined hole , extended reach well and horizontal well , therefore , friction and wear between casing and drill pipe became a severe problem 在深井、超深井、大斜度井、大位移井及水平井中，钻井时间延长、钻柱作用在套管上的侧向力增高，因此套管和钻柱的摩擦与磨损问题越来越突出。
With the development of the new technology of drilling , the exploitation of deep well and over - deep well needs small size bit . because one - cone bit has the advantages of the three - cone bit and the pdc bit and it makes for their disadvantages , so the one - cone bit is the important chose to drill the small well 随着钻探新技术的发展，开发深井和超深井技术要求钻头尺寸小型化，由于单牙轮钻头具有三牙轮钻头和pdc钻头的优点，同时又弥补了二者的不足。
