The two most dominant factors in wax deposition are: 1. Brownian diffusion of wax forming molecules toward and adhesion of wax crystals at the wall. The rate of adhesion is governed by the temperature difference between wall and fluid and the wax crystal formation rate. 2. Shearing of the wax molecules and crystals due to the hydrodynamic drag of the flowing fluid. The rate of shearing and shear force depends largely on the flow rate, viscosity, and other system parameters. As the deposit thickness increases so is the shear rate due to the decrease in the flow area and increase in flow velocity. This increase in shear rate causes an increase in the shear stress on wax molecules and formed wax crystals which acts to diminish the wax deposition rate. This diminishing effect of shear rate on wax deposition rate has been empirically correlated with Shear Stress, τ, from actual wax deposition field data and lab dynamic testing data. The correlation is being used to calculate wax deposition in conduits using mainly but not exclusively cold plate data. The overall approach consists of measuring the amount of wax deposited on a cold plate under static conditions to capture accurately the wax molecule diffusion behavior. This along with other data is used to estimate the initial 24-hour wax deposition rate in a pipeline carrying the tested oil using the new correlation that is presented in this paper. A compositional multiphase wax deposition simulator is then utilized to predict the wax deposition in a pipeline carrying the tested live or dead oil, after it has been fine-tuned to the 24-hour wax deposition rate calculated with the correlation.
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