Abstract: A method for combined characterization of pore structure includes steps as follows. Firstly, CO2, N2 and high-pressure mercury intrusion porosimetry characterization curves are plotted based on actual measurement data, then, average values of the overlapping range of the CO2 and N2 characterization curves are calculated, and a function yi?=ƒ(x) is fitted. Each pore volume yi? corresponding to each pore diameter xi is calculated, and a curve is plotted with xi as a horizontal coordinate and yi? as a vertical coordinate, thereby obtaining a characterization curve of the overlapping range between CO2 and N2 adsorptions. The same data processing is used to process the overlapping range data of the N2 and high-pressure mercury intrusion porosimetry characterization curves, to obtain the characterization curve between them. The characterization curves are spliced with the original CO2, N2, and high-pressure mercury intrusion porosimetry characterization curves to obtain a combined characterization curve.

Abstract: A method for calculating a surface relaxation rate of a shale includes: a relaxation time T distribution curve and a pore throat radius r distribution curve are obtained through experiments; abscissas of the two distribution curves are standardized, and the abscissa of the relaxation time T distribution curve is expanded or shrunk to ensure an abscissa value corresponding to a maximum ordinate value in the transformed relaxation time T distribution curve is same as an abscissa value corresponding to a maximum ordinate value in the pore throat radius r distribution curve; straight lines with a number of N parallel to a y-axis of a combined curve graph including the two distribution curves are drawn and a ? value corresponding to each straight line is calculated; and ? value with the number of N are processed to obtain a final surface relaxation rate ??.