利用地层综合系数法评价及优选钻头

常规钻头选型或者通过钻头的实际使用效果(如钻头进尺、每米成本、机械钻速等参数)，或者通过地层岩石力学的一个或几个参数来进行，但由于钻头在井下受多种地层力学参数的影响，常规方法难以选出最适合本地区的钻头型号。阐述了一种既考虑钻头的经济效益又考虑钻头钻遇地层的岩石力学特性来进行钻头评价和选型的方法，即“地层综合系数法”，并给出了该方法的计算步骤。应用该方法既可以对钻头的预期表现进行评价，也可以进行钻头优选。

Selection and Evaluation of Bits Based on Integrative Formation Coefficient

In the past, the bit selection was decided either by parameters which could reflect the performance of the bit such as ROP, cost per foot, bit drilling footage or by one or several rock mechanics parameters of the formations which would be encountered in the drilling process. However, the bit performance is affected by many rock mechanics parameters of the formations. This paper presents a method which not only takes the consideration of economic benefit of the bit but also rock mechanics parameters of the formations. The method is called the integrative formation coefficient. The process for calculating the integrative formation coefficient is given in this paper. The method can not only be used to predict the bit performance in the offset wells but also to optimize the bit selections.