Abrasiveness evaluation of rock–cone bit based on fractured cuttings

Abstract

This paper looks at the influence of the sorting coefficient, average particle size and quartz content on the abrasion rate of the cone bit. This paper uses rock drillability experiments, particle sizing tests and XRD mineral component analyses as methodology. The results show that the larger the average particle size and sorting coefficient, the smaller the real contact area between the bit and the rock surface, the smaller the friction force. Meanwhile, the volume of the fractured cuttings increased. The results also show that the less the quartz content, the less hard points in the rock. All these factors lead to the reduction in drill bit damage. Because of the strong correlation among the factors of abrasiveness, this paper develops a model of the drill bit abrasion using the partial least square method. The main factors of the model are the grain size distribution and the quartz content of the rock. This model can also be used in the selection of drill bit type and the classification of rock abrasion.