Application of PDC bits in air drilling of Puguang-10 well

It has long been held that the penetration rate of PDC bits is lower than roller bits during air drilling.Owing to the poor heat delivery capability of air drilling,the compact sleet of PDC bits is easily to be damaged that will result in their early failure.Therefore,roller bits are more widely used in air drilling than PDC bits.The major objectives of applying PDC bits in air drilling of Puguang-10 lie in verifying the adaptability of PDC bits and developing approaches to control hole deviation and improve drilling efficiency in high inclined formation of low rock drillability.The penetration rate can be increased by applying PDC with lower weight on the bit.In addition,hole deviation can be effectively control and drilling efficiency can be improved based on using PDC and tapered inclining prevention drilling tools in air drilling of Puguang 10.The maximum deviation angle of Puguang 10 is only 2.59°,smaller than that of its adjacent well,while,the footage drilled is 1517.8 m,and the penetration rate is 8.63 m/h,which is also higher than that of the adjacent well.The believes that heat disseminating capacity of gas is not the basic cause of shortening the life of PDC bits but only affects the hole cleaning and the volume of gas passing through the bits.Hole deviation can be effectively controlled and drilling efficiency can be improved by applying PDC bits and tapered inclining prevention drilling tools in air drilling.