Systematic approach to study Asphaltene deposition modeling in reservoir -Kupal as Case Study

Asphaltene deposition in reservoir rock is one of the main problems during production in some oil fields. Asphaltene deposition in porous media damages the reservoir by reducing rock permeability or changing the wettability of the formation. These damages are serious problems because removing them is too hard and expensive and sometimes impossible. Therefore, production condition should be designed in a way to prevent asphaltene deposition. In order to reduce or prevent asphaltene deposition, it is vital to understand the mechanism of asphaltene deposition in porous media. This paper tries to study systematically the problem of production decline which are caused by asphaltene deposition in Kupal Bangastan formation, by using thermodynamic principles and reservoir modeling. Thermodynamic modeling results show that even before starting production from this field asphaltene had precipitation in reservoir. Single well model based on geological data was built in order to study the mechanism of asphaltene deposition and also to evaluate its damages to reservoir formation. Different scenarios of asphaltene deposition through porous media were matched with pressure decline during production life of several wells. The results show that most of the formation damage occurs in the well bore and deep part of the reservoir is not affected by asphaltene yet. Furthermore field data shows that wellbore damages could be removed easily with stimulation which was confirmed by simulation modeling