A New Macroscopic NucleationModel for Simulation of theSolution Gas Drive in Heavy Oils

摘要

Presence and behaviour of solution gas-drive effect appearsto be critical to the cold production process. This process is nota well-understood production mechanism because a wide rangeof different petrophysical parameters and experimental factorsinteract in a rather complex way. Over the past years, numberof efforts has been made, in many institutions, in order tounderstand and model the solution gas-drive mechanism inprimary heavy oil recovery. Conventional simulations succeedin matching actual field productions but are not reliable forprediction forecast purposes (large uncertainties on recoveryfactors). If matching work on long core depletion experiments issatisfactory in terms of oil and gas productions, it fails topredict the gas saturation gradients.In this context, it has been stated that it was necessary todevelop new tools in order to:? Test efficiently new modelling approaches, allowingsensitivities to physical measurable parameters ? Simulate and match heavy oil long core depletionexperiments data (productions, gas saturation gradients)? Issue recommendations to improve current simulationtools.In this paper, we present a new'macroscopic' approach, atthe Darcy's scale whose advantages are that of a modelling bya continuous equations system, with a limited number ofparameters, having a physical meaning (measurable).The development of this phenomenological code is ongoingin order to account for the fundamental steps of thedepressurisation process, from nucleation of bubbles, to theirgrowth by solute diffusion and expansion, to the final stages ofcoalescence, migration, and production.