Abstract

In the oil field, well completion is the process of making a well ready for production. Completion tools are typically placed on a completion tubing string and then lowered into the wellbore. Downhole completion tasks require overpull, slack off, or turns on the tubing string at the rig floor in order to maneuverer these downhole tools. One common task is to overcome locking and locating mechanisms (shear pins, collets, etc.) to release a tool as part of its setting process. The release of locking mechanisms, however, can induce significant sudden movement of the completion tubing string and generate stress waves propagating in the completion tubing string. Consequently, this can potentially lead to undesirable events, such as packer element swab off, premature shear of other neighbouring locking mechanisms, etc. In this paper, a dynamic finite element analysis (FEA) model has been developed to evaluate the impact of dynamic loading on the completion string. The majority of the completion tubing string is modelled by 3D beam elements with cross sectional moment of inertia accurately represented. Specific tool components of interest are explicitly represented by continuum elements. The model is used to analyze the complex physical phenomena such as stress wave propagation, fluid-tubular interaction, fluid drag on pipe, friction between pipe and wellbore, etc. Two case studies are presented. The first case study discusses the impact of shearing of a shear joint by overpull of a completion string before a packer element is set. The second case study discusses the design of a completion string that involves the release of two locking mechanisms in one maneuverer. The two case studies demonstrate the effectiveness of the dynamic FEA model, as well as provide quantitative predictions and mechanistic insights of the high-impact dynamic loading. High-fidelity FEA modelling enables timely quantitative guidelines for oil field operations.