Laboratory flow experiments are the basis for hydrodynamic calculations and oil recovery forecasting. Current paper discusses some methodological aspects of these experiments. The lack of generally accepted measuring standards for the oil displacement coefficient and relative permeability brings some distortion of data obtained by different laboratories. It turns out that hydrodynamic calculations (including those that undergo examination by the central development commission) can be based on experimental values that have the same name, but were obtained in different ways. The first part of the paper discusses the end effect and various indirect methods of measuring current water saturation during a flow experiment – measuring of the core electrical resistance and x-ray scanning. Some recommendations are given to minimize the influence of the end effect on the measurement result. The use of indirect saturation control methods can lead to a distorted understanding of the oil displacement coefficient and relative permeability curves. For this case, the paper gives an important recommendation about the need for direct measurement of core saturation after a flow experiment using classical Dean-Stark apparatus. The second part of the paper discusses some features of working with rocks that have significant clay content. It has been shown that after core samples are saturated with reservoir water, before a flow experiment, a long soak in the saturating liquid may be required, going far beyond the recommended 16–24 hours. The paper presents the results of measuring the permeability of a core sample over a period of 2 weeks that clearly show the variability of the reservoir properties of the rock during this period.
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