中文摘要：

针对长岭气田登娄库组致密砂岩地层硬、研磨性强、可钻性级别高、钻头优选困难的现状，提出以改进灰色聚类法优选钻头。以改进灰色聚类法优选钻头是将同一区块特定层位已使用过的各个钻头作为聚类对象集，评价钻头的各个指标，如钻头进尺、机械钻速、钻头使用时间及钻头成本等作为聚类指标集，再给出聚类标准集后，即可给出各聚类对象对各聚类标准的聚类系数，通过比较聚类系数大小得出钻头类型的优劣。与常规灰色聚类法相比，该聚类结果更加符合实际情况。长岭气田某些层段上实钻资料应用表明，以改进灰色聚类法选择钻头能有效提高钻井速度，缩短钻井周期，降低钻井成本。

英文摘要：

The tight sandstone in the Denglouku formation of Changling Gasfield is characterized by hardness, strong abrasiveness, high grade of drillability and difficult selection of drilling bit. Therefore, it is proposed that the improved grey clustering method is used to optimize the bit. The bit optimization means that the bits already used in the special positions are taken as the clustering object set to assess the indexes of the bits, such as bit footage, rate of penetration, bit service time and bit cost which are taken as the clustering index set. Then, the clustering standard set is given and the clustering coefficients of the clustering objects to the clustering standards are offered. The advantages or disadvantages of bits are determined by comparing the clustering coefficients. Compared with normal clustering methods, the clustering result is more in agreement with the practical condition. The practical drilling data of application in some intervals of Changling Gasfield show that adoption of the improved grey clustering method can effectively improve drilling speed, shorten drilling cycle and reduce drilling cost.