METHOD FOR LOCALIZATION OF PROMISING ZONES IN OIL-PRODUCING STRATA Russian patent published in 2021 - IPC G01V1/28 G01V1/30 G01V1/48 G01V1/50 G01V11/00 E21B47/07 

FIELD: oil industry.

SUBSTANCE: invention relates to the field of oil industry and can be used in the development of oil deposits of unconventional reservoirs of oil-source strata of the Bazhenov formation. A method for localization of promising zones in oil-source strata has been announced, which includes well surveys, comprehensive analysis and interpretation of results, core studies, parameter verification, mapping and their joint analysis. According to the proposed method, the values of Poisson’s ratio in the oil source reservoir are obtained, its power value is averaged within the interval of the oil source reservoir, its effective value is found for each well and a map of the values of Poisson’s ratio is built. The type of kerogen with its kinetic spectrum is established, the thermal history of the oil-producing reservoir is determined. A map of the depths of the modern occurrence of the roof of oil-producing deposits is built as well as a map of the modern reservoir temperatures of the oil-producing reservoir, a map of the concentration of kerogen in the rocks of oil-producing deposits in paleoenvironment. The conformance of the kinetic spectrum of kerogen to the thermal history of the oil-source reservoir is verified on the basis of numerical modeling of the kinetics of the process of thermal decomposition of kerogen according to the previously determined thermal history of the oil-source reservoir. Then, numerical modeling of the process of laboratory pyrolysis of kerogen, which has passed the stage of modeling the thermal history, is carried out, the calculated values of the degree of realization of the kerogen generation potential and similar values calculated from the data of laboratory pyrolysis of the core for specific wells are compared. Numerical modeling of changes in pore pressure in the oil-source reservoir is carried out and a map of potentially achievable pore pressure in oil-source deposits is built based on the kinetics of kerogen transformation and material balance. Based on the map of Poisson’s ratio values for the oil-source reservoir and the map of the current depths of the formation top of the oil-source reservoir, a map of the pressure of cracking in the oil-producing reservoir is constructed. Then, it is compared point-by-point with a map of potentially achievable pore pressure and promising zones are identified in which the pore pressure reaches values equal to the crack formation pressure, while the crack formation pressure is determined based on the stress-strain state of the oil-source reservoir for a rupture model on the surface of a spherical pore.

EFFECT: increase in the accuracy of determining the localization of promising zones in the oil-producing strata, taking into account the degree of maturity of the oil-producing rock.

1 cl, 9 dwg