Modeling of Wax Precipitation in Crude Oils

Production of crude oil from high temperature reservoir from subsurface to
surface will reduce the oil temperature and it will lead to fonnation of wax. The wax
precipitation is common in petroleum industry which gives challenges to the flow
assurance. The major problems that caused by wax formation are reduction of
production, increased pressure drop in pipeline, and high risk of getting a pipeline gauge
stuck during maintenance operations. It can be very costly to solve the problems caused
by wax and may lead to loses. The objective of this project is to develop an
thermodynamic model to predict the Wax Appearance Temperature (WAT) by
determining the suitable solubility parameters, fusion enthalpies and fusion temperatures.
Recognizing the WA T may improve cost saving of crude oil production. Early
prevention can be carried out to avoid wax precipitation in the operating facilities and
maintain the performance and efficiency of equipments. In order to produce an accurate
model in predicting wax forming temperature, the liquid-solid transition factors need to
be considered. The thermodynamic model for estimation of W AT is being developed by
finding the details of each parameter which will be inserted into MA TLAB for
calculation. The effect of carbon numbers, fusion enthalpies and solubility parameters to
the model has been obtained. The results of this model have been compared with the
existing model. In conclusion, the suitable parameters for the wax prediction model have
been determined and a thermodynamic model has been developed to predict W AT and
wax amount.