A New Method for Bit Selection Based on Pattern Recognition

In drilling engineering, poor bit performance often results from unreasonable bit selections and mechanical properties that are unsuitable for certain formations. Therefore, a new method for selecting bit types based on the pattern recognition method was established. First, a cluster analysis was performed on the drilled strata and bits were adopted according to pattern recognition theory, and then a stratum-bit standard or guide was constructed. Second, the strata to be drilled were identified and classified by means of K-NN algorithm, and the optimum bit was selected on the basis of the stratum-bit standard mode. Finally, the bit selection scheme was provided and applied to two wells in Dongping and Niudong Blocks, Qinghai Oilfield. Practical drilling data showed that drilling rate and footage in the two wells improved when the recommendations were followed. It is indicated that new bit selection method based on pattern recognition not only considered various drilling resistant parameters of strata, but also focused on bit performance. So, the new bit selection scheme is considered to be more reasonable that earlier approaches, and it is possible to significantly improve the drilling rate and efficiency.