Vafaei-Sefti - Department of chemical engineering, Tarbiat Modarres University, Tehran,I.R,Iran
Mosavi-Dehghani - N.I.O.Cresearch Institute, Rey City,Teharn,I.R, Iran
Mansoori - Chemical Engineering, Department,University of Illinoois,۸۱۰s,Clinton Street ,Chicago,IL۶۰۶۰۷,USA

Asphaltenes flocculation and deposition during natural depletion and/or miscible gas injection in EOR processes is a common and unfavorable problem in oil field in all over the world. Complexity of asphaltene structure and high affinity of these molecules to absorb on surfaces such as rock surfaces lead to difficultiesin their deposition prediction.There are so many models which they can predict asphaltene precipitation,flocculation, aggregation or deposition in static state.Each maodel will be able to predict only some aspect of asphaltene deposition due to limited parameters such as temperature, pressure and/or miscible gas injection.This work is a modification on previous work of authors on association modeling of asphaltene deposition. In this work, it has been attemp to use applied thermodynamic principles conjugated withsome postulats, which result to simplification and applicable model for prediction of asphaltene deposition due to pressure and miscible gas injection. Association term has been incorporated in EOS by a simple association factors which they were obtained from molecular weight distribution ( fractional molecular weight) and average asphaltene molecular weight. In this work, using some linear relations for EOS parameters of asphaltene fractions as function of fractional molecular weight, there is no need to define asphaltene critical properties such as critical temperature and pressure. This modeling is able to predict asphaltene deposition and amount ofasphaltene deposition due to pressure variations and miscible gas injection and some special cases such as CO2 flooding. The results obtained from htis work are ingood agreement with experimental and other works results.

Dryer,Exergy modeling,Energy saving,Reduction of losses