Проявление капиллярных концевых эффектов при фильтрационных исследованиях

Abstract

From theoretical studies and experiments on the core, the so-called capillary end effect, or, as it is also called, the effect of phases capillary entrapment, is known. When carrying out laboratory experiments to determine the relative phase permeabilities, capillary end effects appear on the core models of the reservoir. These effects can occur as a result of capillary ruptures at the ends of the core sample, which leads to the accumulation of one phase in relation to the other, and thereby affects the movement and retention of the fluid. The region of capillary end effect, which occurs due to the rupture of capillaries at the exit from the sample, affects the change in pressure drop and saturation of a particular fluid. If the influence of capillary end effects is significant, then the experimental conditions are modeled incorrectly, which can lead to serious errors in predicting the productivity of the studied formation. This paper presents the results of studying the porosity-permeability properties of determining the relative phase permeabilities and the studies analysis of the capillary end effects influence mechanism on the filtration capacity of rock samples during laboratory studies using the example of terrigenous and carbonate types of the Pavlovskoye reservoir. According to the results of the studies, the significance of capillary end effects in filtration experiments was established using the example of determining the relative phase permeabilities. Recommendations are given with the aim of minimizing the negative influence of end effects. Capillary effects can be overcome by increasing the length of the test sample, as well as by increasing the flow rate of the fluid during a laboratory experiment to determine the relative phase permeabilities.