Modeling wax deposition in crude oil

Abstract

Wax precipitation and deposition is one of the most important flow assurance problems in production and transportation of crude oil. A thermodynamic and experimental study is proposed for determination of wax deposition and study of its effect on design and operation of waxy crude oil production systems by predicting the wax appearance temperature (WAT) and amount of wax formed under different conditions. We will develop a thermodynamic model in order to calculate the equilibrium between oil and wax phases during the flow of crude oil. This thermodynamic model will help to investigate the effect of different parameters and compare the obtained results with experimental data. A comparison of different activity coefficients will be presented in order to get the best results by using appropriate activity coefficient model for the description of solid and liquid phases in the thermodynamic model of wax precipitation. Experimental measurements examining wax deposition proposed in this study, include determination of the wax appearance temperature (WAT), measuring the amount of wax precipitated under varying temperature and pressure conditions, viscosity measurements to identify the wax crystallization and agglomeration, characterization of paraffinic crude oils by experimental determination of their properties. We expect that the results of this study will help in providing a strategy and methodology to perform an effective diagnosis so as to achieve a high success in treating wax deposition problems, as well as designing an accurate system for production from reservoirs containing paraffinic oils, to avoid or minimize the phenomenon of wax deposition