The movement of a petroleum phase through a porous rock matrix can be simulated by core flooding experiments in the laboratory, and the properties of each system can be characterized by measurement of the oil saturations and permeabilities of the fluid phases. The importance of the oil phase, water phase, and rock matrix composition has been studied in short core flooding experiments at laboratory conditions. End-point saturations, breakthrough volumes, and fluid phase end-point permeabilities have been determined for oil flooding and subsequent water flooding of cleaned, epoxy-coated cores. Factorial designs for screening experiments are used so that both direct and interactive effects of the variations in experimental conditions can be evaluated. Three different designs have been used to evaluate the effects of different core matrix compositions : the core length, crude or refined oil phases, and addition of short-chain organic acids Do the water phase. The results show that all experimental factors influence the measured parameters of the system. The different designs show different types of variation. A single direction of variability corresponding to wettability is not observed. Interactive effects from combinations of variables are important for all the measured properties and should be taken into account in further investigations.