Generation of Oil-Wet Model Sandstone Surfaces

Abstract

ABSTRACT A technique for modifying the natural water-wetting behavior of clean, dry, Berea sandstone is discussed. The method involves chemically incorporating the vapor of an organosilane onto the surface of the rocks at elevated temperature and reduced pressure. This paper focuses on the first stage of the project, in which the technique was evaluated by silylating quartz plates as sandstone analogs. When the reaction was carried out with quartz at 275 C, strongly oil-wetting surfaces were generated and the wettability was maintained for extended periods of time upon soaking the plates in various liquids. Plates soaked in brine remained oil-wetting for 22 weeks. Altered wettability of plates soaked in toluene or dodecane persisted for 24 weeks. Application of the newly-developed dynamic Wilhelmy plate technique for rapidly and conveniently evaluating the wetting properties of silylated plates is discussed. Using a modification of the procedure described for silylating the quartz plates, we were recently able to prepare samples of strongly oil-wetting Berea sandstone.