A New Model for Water Droplet Settlement in Crude Oil; Application for Crude Oil Storage Tanks

Nowadays, as a result of oil fieldsaging, the increasing rate of water production has become a challenging problem for most crude dehydration and desalting plants. The fact that such plants cannot meet the required crude oil specification has brought about increasing load on the crude storage tanks. In the current study, an innovative mathematical model is developed for dynamic prediction of the water cut and water drain rate. The model makes use of a normal distribution for probability density of the water droplet sizes, discretizes the volume along the length, and updates number of each droplet size for each element after specified time step. The model is successfully utilized for prediction of water cut and drain volume of a crude storage tank. Parameters, namely mean droplet size and standard deviation areestimated to tune the model with field data (drain volume). It is found that the modelhas great potential for water settlement prediction which can be used to prepare a more efficient draining procedure for crude oil storage tanks. The optimized parameters are estimated 38.56 μm and 7.83e-06 for mean droplet size and standard deviation respectively corresponding to AARDof 4.76 %.

Keywords:

Crude oil , dehydration , storage tank , water settlement , droplet size.