Abstract: Drillability tests have been made on core samples from the formations encountered in oil well drilling.The average time interval in seconds is named Drillability Time (DT),and the logarithm of the DT to the base 2-the Drillability Classification Grade (DCO).Statistical analysis of DCG has proved to be of normal distribution,The sample mean is x=5.4438 and the standard deviation S_x=1.7498.The formations can be classified into ten grades in accordance with the DCG,and the percent volume of each grade of formation can be determined with the distribution function.Application of the DCG to the estimation of the total amount of bits required is discussed,as well as for other purposes.The drillability test apparatus used has been proved simple and reliable.

摘要： 本文根据石油钻井中所遇到的地层岩样所做可钻性测定。以平均钻时(秒)DT为钻时样本,取DT以2为底的对数为可钻性等级(DCG)。按统计分析表明它服从正态分布,样品平均值x=5.4438,均方差S_x=1.7498,油田地层按可钻性等级共分十级,每级地层所占比例的百分数可以分布函数求出。本文讨论了DCG用于估算所需钻头用量的问题及其它有关问题。