THE GRADES OF DRILLABILITY AND BIT TYPE SELECTION IN YANCHENG AREA

Reasonable selection of bit is one of the important approaches to increase ROP and decrease drilling cost.The logging information is used to predict drillability of rock,and the computer program is written,therefore,the profile of continous rock drillability has been established in Yancheng area.According to the value of rock drillability and method of cost for every meter,the optimum bits are selected,and scientific evidences have been provided for the reasonable use of bits.