METHOD OF DETERMINATION OF SURFACE PROPERTIES OF ROCKS Russian patent published in 2016 - IPC G01N13/00 G01N15/08 

FIELD: mining.

SUBSTANCE: extracted and dehydrated sample of rocks core is pre-saturated with produced water or simulated produced water under vacuum, and initial water content in rock samples is determined, then sample is centrifuged in standard basket to displace water by air at different angular speeds in range from minimum centrifuge speed to speed ensuring creation of the residual water saturation in sample, the achieved minimum water saturation is recorded for each speed of the centrifuge rotor in said range, sample weight with residual water saturation is determined, and capillary pressure curve is plotted, by it the stochastic distribution of the drained pores as per sizes is determined, then the core sample with residual water is saturated with oil or iso-viscous model of oil under vacuum, quantity of hydrocarbons is determined in sample pores, sample is centrifuged in invertor basket to replace the hydrocarbons by liquid displacing agent with different angular speed in range from minimum centrifuge speed to speed ensuring residual oil saturation, minimum achieved oil saturation is recorded at each speed of centrifuge rotor in said range, and capillary impregnation curve is plotted, based on it by means of differentiation of areas of distribution of drained pores the distribution of sizes pores impregnated by the displacing agent is determined, on this basis relationship of calculated cos of contact angle of wetting depending vs. pore size is plotted, on the obtained curve the flex point is fixed, relatively it areas of hydrocarbons are rated as held by capillary forces and by adsorption forces.

EFFECT: additional information on properties of water saturated rocks-oil reservoirs using standard petrophysical equipment.

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