Abstract:Synthetic diamond was developed in China since 1963. In 1970s, it was expanded to minegeological drilling. From 1971 to 1991, in the whole nation, totally 8, 710 drilling rigs had beenoperated to complete 54, 823 holes and a total of 16 million meters had been drilled. 65 thousandbits were used, of which 1/3 were synthetic diamond bits. The maximum average drilling depthof the bits for each year was 38. 2m. In the middle 1970s, wireline core drilling was spreaded.After this, diamond hydro - hammer drilling and downhole bit were developed. Synthetic diamond drilling has achieved notable results, which were particularly shownd in the following aspects:(1)Drilling rigs and tools, drilling fluids, drilling parameters, drilling instruments and relevant drilling management techniques were configured.(2)There are high level scientific research personnel on drilling equipment, tools, instruments, drilling fluids, bits and drilling technique and there are also high level constructors.(3)Classification of rock drillability, which can guide drilling process, bit designing and appropriate bit selection, has been made to be suitable to diamond drilling.(4)Variable cutters have been developed from synthetic monocrystalline to polycrystalline,PDC and synthetic carbonado.(5)According to the physical and mechanical properties of rocks, moulding of bit crown,senation of bit matrix, variety of the waterway design, standardization of diamond parametersselection and senation of specifications and dimensions have been formed. Diamond bit manufacturing techniques has come into being. There are resistance and medium frequency sinteringprocess, high frequency sintering process of pressing, electroplating, infiltration process of coldpressing and infiltration process with vibration, vacuum sintering and braze welding techniquewhich have been used in bit manufacturing.(6)Drilling equipment and drilling tools inspection centers have been established, withwhich the corresponding qualities can be guarranteed.
