Scaling up of wax deposition rates from small scale laboratory flow loops to field pipelines is generally problematic due to uncertainties in currently available state of the art models. Uncertainties in modeling include the right choice of mass transfer mechanism, the extent of shear effects, and the choice of aging/internal diffusion parameter. Traditional approach has been to use a model to tune to small scale flow loop data, and use that model to predict deposition rates in the field – with the understanding that the field predictions will usually be conservative. This approach, however, can lead to wasted CAPEX and/or OPEX, and may not work for economically challenged/ marginal projects.
To address this problem, we have built a large-scale flow loop (4" pipe ID, and 120 ft long test section) for testing wax deposition. A variety of experiments were performed changing the operating conditions to observe the effect on the deposition rate. Different wax deposition software, both commercial and R&D, were tested against the data. Experiments were also performed on a small-scale loop to study scale up issues. Based on this work, a more robust approach to scale up of wax deposition rates has been developed.
