METHOD OF DETERMINING CONTENT OF FACIES IN VOLUME OF OIL-AND-GAS-BEARING FORMATION Russian patent published in 2025 - IPC G01V20/00 

FIELD: data processing; mining.

SUBSTANCE: invention relates to geological modelling of hydrocarbon deposits. Disclosed is a method of determining content of facies in oil-and-gas-bearing formation, involving: determination of conditions for formation of even-aged rocks by material composition, conducting mineral and petrographic analysis of sedimentary rocks of the investigated object, including the study of petrographic polished sections under a microscope, performance of section lithological separation and construction of lithological columns of wells, interpretation of materials of geophysical studies of wells, establishment of a number of facies based on a set of diagnostic features and determination of the sedimentation environment, constructing a geological model of the formation under investigation. From the series of established facies, facies are selected, characterized by specific shapes, sizes and position in space in accordance with the direction of removal of the sedimentary material. Thickness of sedimentary bodies corresponding to specified facies is measured by means of establishment of boundaries of sedimentary bodies in core, comparison of established limits with data of geophysical researches of wells and measurement of difference of true depths of upper and lower boundaries. Thickness of sedimentary bodies is measured by means of establishment of boundaries of sedimentary bodies on the basis of data of geophysical investigations of wells and measurement of difference of true depths of upper and lower boundaries. Minimum and maximum sizes of sedimentary bodies are set. Minimum content of facies in volume of oil-and-gas-bearing formation is determined by placing in volume of geological model of formation only sedimentary bodies intersected by wells, shape, size and position of which in multivariance conditions provide minimum volume of facies. Then, maximum content of facies in volume of oil-and-gas-bearing formation is determined by means of arrangement in volume of geological model of the formation of maximum possible number of sedimentary bodies for the specified rock formation conditions, crossed and not crossed with wells, shape, dimensions and position of which provide maximum volumes of facies under conditions of multivariance. Then, based on versions of models with minimum and maximum content of facies, average value of content of facies is determined as mathematical expectation of discrete random value. Minimum and maximum values of facies content in volume of oil and gas bearing formation are used for analysis of uncertainties and evaluation of risks when calculating initial geological reserves of hydrocarbons.

EFFECT: high reliability of predicting and evaluating uncertainty of content of facies in the volume of oil-and-gas-bearing formations due to taking into account specific shapes, sizes and position in space of sedimentary bodies.

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