Abstract:

Actual data shows that drilling in fractured granite basement rock of Bach Ho Field using 4½ tricone roller bit induced low rate of penetration, short life-time of the bit, broken and dull teeth of bit, drop-out cones… lead to the extension of drilling time. Based on the analysis of statistical data on the actual use of tricone roller bit in fractured granite basement rocks, the physic-mecanical properties of basement rock such as hardness, abrasion combined with the results of research and evaluation the design, rock destruction principle of drill bit, the authors have proposed technology – technical solutions to improve performance and durability of tricone roller bit by reducing force impact of the bit on rock. These slolutions are: change IADC code of the drill bit, increase the number of teeth on the same section, arange teeth to avoid re-contact with the most recent position while drilling, cover the sides of drill bit with alloy, use bearing seal with HAR technology.