Abstract: Drill strings are used in oil and gas production as well as geothermal wells. They experience destructive vibrations, many of which are highly dependent on drill string modes. In this paper, ...

Abstract: Previous research in stability of drillstrings was based on the assumption of constant material specific force, i.e., a bit force that is proportional to the area of cut. Moreover, earlier ...

Abstract: Traditionally, the analysis of stability in drillstrings is based on longitudinal vibrations only. However, field experience indicates the presence of torsional effects in the form of modulations ...

Abstract: Stability of drillstrings equipped with PDC bits depends on many factors such as the design of the drillstring, design of the bit, and formation type. In this paper, we show that the drill ...

Abstract: Drilling costs are significantly influenced by bit performance when drilling in offshore formations. Retrieving and replacing damaged downhole tools is an extraordinarily expensive and time-intensive ...

Abstract: This paper shows the effect of process damping—caused by the interference between the cutter and the previously cut surface—on the stability of drillstrings. The method of including process ...