Method for determining nuclear magnetic resonance T2 cutoff value and fluid saturation of tight oil, and apparatus thereof

The invention provides a method for determining the nuclear magnetic resonance T2 cutoff value and the fluid saturation of tight oil, and an apparatus thereof. The method comprises the following steps: determining the carbon content of a sample to be measured to generate a carbon content determination result; determining the lower limit value of the pore throat radius of the sample to be measured according to the carbon content determination result; and determining the corresponding T2 cutoff value according to the lower limit value of the pore throat radius and the core relaxation rate of the sample to be measured. The T2 cutoff value is calculated by using the lower limit value of the pore throat radius of the tight oil movable fluid of the practical sample in the above scheme, and the lower limit value of the pore throat radius of the tight oil movable fluid of the practical sample is determined by adopting a course to fine pore throat carbon content gradual approximation technology, so the T2 cutoff value obtained in the invention is true.