Experimental Investigation of Permeability Reduction by Asphaltene Deposition in Porous Media

Asphaltene deposition causes serious problems in the oil industry. Variation of oil composition and reservoir pressure is reported to be the most important factors that influence asphaltene deposition. In this work, a series of experiments was carried out to determine the effect of asphaltene deposition on the permeability reduction of carbonate and sandstone rocks by using Iranian live oil. The majority of existing work addresses the deposition of asphaltenes by using dead oil or recombined oil. Very little work currently exists on the deposition of asphaltenes under dynamic conditions by using live oil. Experiments indicated the existence of three type depositional behaviour, continuous deposition for low permeability core; slow steady plugging for high permeability core and steady deposition for medium permeability core. The existence of a continuous plugging regime is of particular concern in the petroleum industry because of increased probability of plugging near the wellbore. Also, effect of rock type was studied and the experimental results shown that the pore volume number values of the injected crude oil are almost higher for the sandstone core as compared to the carbonate core, due to the higher porosity and/or permeability of the sandstone core. In this work, it also was shown that higher asphaltene content of the crude oil causes more permeability reduction of rocks

Keywords:

Asphaltene deposition , Formation damage , Carbonate rock , Sandstone rock , Permeability