METHOD FOR DETERMINING THE OIL DISPLACEMENT COEFFICIENT AT THE PORE SCALE BASED ON 4D MICROTOMOGRAPHY AND A DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2022 - IPC G01N15/08 G01N23/04 

FIELD: oil industry.

SUBSTANCE: claimed group of inventions relates to the oil industry, namely, to special core studies for the design and analysis of the development of oil fields using various flooding systems. A method for determining the oil displacement coefficient at the pore scale based on 4D microtomography is proposed, which consists in making a cylindrical sample from the reservoir rock with a height of 4 to 6 mm and a diameter of 4 to 6 mm.; next, it is placed in an X-ray transparent mobile core holder of a device for X-ray computed microtomography of reservoir rocks, microtomography of a cylindrical sample is performed, followed by segmentation of the effective porosity structure. Next, a cylindrical sample is saturated with reservoir water or a model of reservoir water contrasted with X-ray-dense compounds, oil or oil models are filtered through the sample under specified thermobaric conditions until the water outlet from the sample stops. Next, repeated microtomography of the sample, registration of a three-dimensional image of the sample in the volume of the previously obtained digital model of the original sample, segmentation within the previously allocated effective porosity of the volumes of oil and residual reservoir water are carried out based on differences in X-ray density between the contrasted and non-contrasted phases. The volume of initial oil saturation is determined and oil or oil model is displaced by reservoir water or another displacing agent contrasted with X-ray-dense compounds, and repeated microtomography of the sample is performed, a three-dimensional image of the sample is recorded in the volume of the previously obtained digital model of the initial sample, segmentation within the previously allocated effective porosity of the volumes of residual oil or oil model based on differences in X-ray density between the contrasted and non-contrasted phases. The oil displacement coefficient β is calculated based on the ratio of the volumes of the initial oil saturation Vs.init., residual oil saturation Vs.resid. in the sample. A device for conducting 4D X-ray computer microtomography of reservoir rocks for the implementation of the claimed method, consisting of an X-ray computer microtomograph, a filtration unit, and an X-ray transparent mobile core holder, is also proposed. At the same time, the filtration plant includes a crimp pump, a pressure pump, a manifold for controlling the supply of liquid from the selected container, piston containers for injected liquids.

EFFECT: assessment of the change in oil saturation volumes directly inside the effective porosity of the sample during the oil displacement experiment, which makes it possible to determine the displacement coefficient with greater accuracy.

2 cl, 9 dwg