Abstract
A downhole tool typically encounters shock and vibration under different circumstances, including tool handling, tool transportation and tool operation. The aim of this work is to present a finite element analysis (FEA) method that can simulate non-destructive evaluation tests conducted on downhole tools subject to shock and random vibration. The downhole tool assembly is rigged up to the vibration test table and subjected to a shock signal or a random vibration signal as expected in well conditions. A corresponding three-dimensional finite element model of a downhole tool is developed with component geometry details and relevant interactions between the components, accounting for inertia of components and structural material properties. The method involves a two-part analysis of the finite element model: response spectrum and transient dynamic analysis for shock and random vibration. This simulation predicts the mechanical response of the tool used to determine failure within its operating range. The unique contribution of this work is that the analysis approach can capture the effects of the response of the tool assembly similar to non-destructive shock and random vibration testing. Comparisons of frequency response tests and structural integrity inspection from simulations versus testing on the downhole tool establish the fidelity of the FEA method as well as additional insights to the load path of the inner components of the tool assembly. The FEA method thus provides an alternative digital identification of the potential failure under shock and random vibration in downhole tool assemblies that is cost-effective and time-efficient, to reveal potential structural integrity issues of downhole tools in early design stages and identify critical components in the tools that need to be monitored during their physical testing.
