三角形PCD的质量状况及应用前景

Quality condition and application prospect of triangular PCD

三角形PCD的剪切破岩方式使其在塑性、塑脆性地层钻进效果较好。国产三角形PCD石油钻头难以见到应有的效果，碎断齿现象严重。通过检测国内外三角形PCD产品性能发现：国产三角形PCD的抗冲击韧性大大低于行业标准规定值；同一批产品的磨耗比数值差异较大；由于自锐性差，在测定磨耗比过程中，当其尖角磨损面较大时易出现发红现象；与国外同类产品相比有较大差距。采用以1／3的圆柱形（80°～85°锥角）PCD替代三角形PCD制作的混合齿钻头，使用效果有明显改善，但仍难以取代三角形PCD钻头在钻进某些地层的特殊作用。国产高质量三角形PCD钻头将会为提高日益增多的超深井复杂地质条件下的钻进效果发挥其应有的作用。

The rock - breaking mode of triangular PCD （ polycrystalline diamond） by shearing action makes it drill better in plastic and plastic - brittle formations. China-made oil bits mounted with triangular PCD can not achieve the proper results due to the serious crushed - and broken teeth phenomenon. By inspecting the properties of triangular PCD products made in China and from abroad, the following conclusions are discovered ： （ 1 ） The impact toughness of China-made triangular PCD is far lower than the value specified in the industrial standards; （2）There exists a big difference in wear and tear ratio among the same batch of products ; （3） In the process of determining wear and tear ratio, the diminution of a triangular PCD begins to turn red easily as the wear area becomes larger due to its poor self - sharpening characteristics ; （ 4 ） There is still a big gap compared with foreign products of the same kind. Performance of a hybrid drill bit mounted with cylindrical PCD （80 -85 cone angle） in place of one -third triangular PCD has been improved obviously, however, it cannot replace the special roles the triangular PCD bit plays in drilling some formations. The high quality triangular PCD bits made in our country will play proper roles in improving drilling performance under complex geologic conditions of more and more ultra - deep wells.