Theoretical study of dependence of screwing of drilling-pipe connector on thread-process cutting tool profile

Abstract

Screwing is one of the main parameters of the quality of a drill string tapered thread tool joint. It indicates the number of screwing operations that can be applied to this tool joint during drilling. Tool joints that have undergone rejection (determined by a specific criterion - the distance between the end faces of the pin and the box before they are start the screwing) are not permitted to screw. The value of this criterion is proportional to the working height of the threadprofile, which decreases during operation. In this article, it is offered to increase the initial value of the criterion of rejection due to the increase of the work height of the thread profile. This can be done without violating the standard but with the use of a modernized profile of the tool for thread turning. This profile makes it possible to increase the crest diameter of the thread and at the same time ensure sufficient tool life. Due to its usage, the resource of the tool joint can increase by 9-14.5%, while the cutter's tool life and cost remain unchanged.