Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
CONTACT PROPERTIES AND MODELLING OF BENTONITE PELLETS DISPLACEMENT FOR PLUGGING AND ABANDONMENT IN OFF-SHORE OIL WELLS
Submission Author:
Fernando Barbosa , PR
Co-Authors:
Fernando Barbosa, Alan Lugarini de Souza, Yamid José García Blanco, Eduardo Matos Germer, Admilson Franco
Presenter: Fernando Barbosa
doi://10.26678/ABCM.COBEM2021.COB2021-0453
Abstract
In recent years, oil and gas companies have been looking for alternative materials for plugging and abandonment (P&A) of wells. One of the emerging options is bentonite pellets, an expansive clay that, when in contact with water, it expands forming a plug. This plug seems to make a more impermeable and environmentally safe barrier, with a much lower cost than the usual Portland cement. One of the multiple technical challenges in the off-shore scenario is to pump huge amounts of bentonite pellets as a two-phase mixture with oil towards a plugging target, an environment that presents high temperatures and pressures. To that end, it is crucial to predict the solid-fluid interactions to avoid troubles such as excessive pressure drop or jamming. In the present work, contact models used in discrete element method (DEM) simulations are calibrated through a series of experimental routines. It is known that the montmorillonite, major component of bentonite, does not expands in oil, which makes the granularity proprieties much more relevant to achieve accurate computational results. Therefore, three experiments widespread in the granular field are conducted, namely, inclined plane, pour angle of repose, and angle of repose with a cylinder. The first one consists in measuring the angle which begins the displacement of a clay sample, thus obtaining the friction coefficient. The second consist in the angle of repose presented in a pile formed by the particles after pouring from a specific height. Finally, the third is the angle of repose obtained after the vertical displacement of a cylindrical recipient. This approach differs from the conventional granular studies since the immersing medium is diesel oil, while most investigations use air or water. With the experimental results in hand, it was possible to properly calibrate the many physical parameters from DEM and obtain a reliable numerical representation of the problem. The simulation results showed excellent agreement with the experimental test cases, allowing us to develop horizontal granular flow studies in an efficient framework confidently.
Keywords
Oil and gas well, Discrete element method, Bentonite pellets, Plugging and abandonment
