Abstract
As the high demand for fossil fuel pushes the frontiers of oil exploration and production into more hostile environments, issues associated with flow assurance have become increasingly important. This is especially true of paraffin wax precipitation and deposition in areas of reduced temperatures, such as the Polar Regions and in deep sea environments. In order to reduce costly remedial operations aimed at removing pipe/tubing blockages resulting from wax deposition, it is essential to predict when, where and how much paraffin wax is deposited during the working life of oilfield installations. In this study, a computer application model capable of predicting wax precipitation and deposition in oilfield installations under various conditions of flow was developed. Thus, a computational flow dynamics (CFD) program named "WD-Predictor" using C++ language was designed and developed with mathematical models that approximate the physical behavior of wax crystallization and deposition systems such as; Property Transport Models (Energy, Momentum and Mass), Thermodynamic Equilibrium Model and Wax Deposition & Erosion Model. The mathematical models developed were discretized while numerical solutions to the discretized models were then developed using appropriate algorithms and pseudo-codes. The "WD-Predictor" was used to estimate the Wax Appearance Temperature (WAT) of three crude samples. The results obtained were compared to an experimental results published; Exp.WAT for oil sample 1 was 87.800°F and Predicted was 89.888°F, for oil sample 2- the Exp. WAT was 114.35°F and predicted was 115.76°F and for oil sample 3, Exp. WAT was 72.950°F while Predicted was 70.620°F. Again, WD-Predictor results were compared with the experimental data extracted from Cordoba and Schall (2001). Above all, WD-Predictor output on wax deposition thickness was also compared with the enthalpy-porosity model proposed by Banki et al. (2008) and in all the WD-Predictor showed consistence in results, in line with these published experimental results. Finally, WD-Predictor was validated with a well-tested simulator PROSPER™ on pressure and temperature profiles using Beggs & Brill Correlations.