METHOD OF CORE SAMPLES POROSITY AND PERMEABILITY STUDY Russian patent published in 2017 - IPC G01N15/00 

FIELD: oil and gas industry.

SUBSTANCE: extracted and dried core samples, taken from the single production facility, are used for the experiment. Preliminarily, the open porosity and absolute permeability of the samples over the gas under the standard conditions are determined. Make the selection from these samples in such a way, that it includes samples with maximum, minimum and average values of the open porosity and absolute permeability (5 or more samples). To study the effective porosity and effective permeability in the core samples, the residual water saturation is created, using the reservoir water model. For the oil deposits reservoir rocks, the samples are then saturated with the kerosene or oil. Each sample is placed in the installation, that allows to determine the change in porosity and permeability according to the liquid (for oil deposits) or to the gas (for gas deposits). In the installation, the effective stresses are increased by the steps up to the value corresponding to the initial reservoir conditions. Stand the sample until the permeability value is stabilized. Increase the effective stresses up to the value corresponding to the reservoir pressure decrease by the certain value (for example, 10 MPa), and stand the sample until the permeability value is stabilized. The cycles of increase and prolonged keeping of the core samples are repeated at least three times. Then the effective stresses are reduced stepwise with the number of steps not less than five.

EFFECT: determination of the porosity and permeability changes relations of core samples during the fluid filtration and the action of the various sizes effective stresses up to stabilization of the core samples permeability in at least three modes of exposure.

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