METHOD FOR DETERMINING THE QUANTITY OF POLYMER HOLD IN A POROUS MEDIUM Russian patent published in 2023 - IPC G01N24/08 

FIELD: polymers study.

SUBSTANCE: invention is intended to quantitatively study the retention of polymers used for enhanced oil recovery in porous media. The essence of the invention lies in the fact that pore water is removed from the sample of the porous medium by drying the sample. The NMR method is used to measure the initial map of longitudinal and transverse relaxation times, which characterizes the initial state of the sample. The sample is saturated with a salt solution, the amount of which corresponds to the natural salt content in the formation water, prepared on the basis of D₂O. Then, the polymer is dissolved in an aqueous solution of salts, the amount of which corresponds to the natural content of salts in the formation water, based on H₂O, and the resulting polymer solution is injected into the test sample. The polymer solution is displaced from the sample by injection of a salt solution based on D₂O. Using the NMR method, a map of the longitudinal and transverse relaxation times of the sample is measured, the original map of the longitudinal and transverse relaxation times is subtracted from the measured map, and a difference map of the longitudinal and transverse relaxation times is built. At least two consecutive NMR measurements are made of maps of longitudinal and transverse relaxation times of polymer solutions in a separate container at various known concentrations to build a calibration dependence. Based on the constructed difference map of the longitudinal and transverse relaxation times, using the constructed calibration dependence, the amounts of hydrogen associated with water and polymer molecules are calculated, and the amount of the polymer solution mechanically blocked in the sample and the amount of the adsorbed polymer are determined.

EFFECT: providing the ability to determine the amount of polymer adsorbed on the surface and blocked in the sample of the porous medium with high accuracy.

1 cl, 6 dwg