Contact angles on quartz induced by adsorption of heteropolar hydrocarbons

The wetting behavior induced by the adsorption of crude oil components onto mineral substrates initially covered with brine is of special importance t o petroleum engineering. The wettability of reservoir rock is a controlling factor in the efficiency of oil recovery from the swept zone of a waterflo od. The effect of the adsorption of polar components from crude oil on the wetting properties of quartz plates was investigated by the dynamic Wilhelm y plate technique. Force-distance relationships were measured for treated q uartz plates passing through oleic-aqueous interfaces. Water receding and a dvancing contact angles under dynamic conditions were obtained. Changes in the wetting of the quartz plate from a completely water-wet state were indu ced by adsorption from crude oil or solutions of its components. Different wetting states were developed by varying the oil composition, aqueous phase pH, temperature, time of adsorption, the solvents used to remove excess cr ude oil, and the probe oil used in contact angle measurements. Some importa nt features of wetting, contact angle hysteresis and slippage of the three- phase contact line, are presented. Organic films adsorbed from the crude oi l were examined by atomic force microscopy.