A new method for evaluating wettability by measuring oil-wet percent of rocks

The adsorption of asphaltene and resin on quartz sands makes the surface property of the quartz sands transfer from strong water-wet to oil-wet.But the transferring effect is not a function of the concentrations of asphaltene and resin.The oleophilic-site density on rock's surface can be quantified by measuring the concentration difference of heptanol solution,namely measuring the difference between the initial concentration of heptanol solution and the balance concentration due to adsorption on the surface of rock.Quantifying the oil-wet percent of rock's surface can reflect the change of the wettability perfectly.Experimental results show that the heptanol method is realizable to quantify the oil-wet percent.