METHOD FOR DETERMINING THE GROUP COMPOSITION OF BITUMEN IN ROCK USING LOW-FREQUENCY NMR RELAXOMETRY Russian patent published in 2023 - IPC G01N24/08 G01N1/28 

FIELD: oil development and production.

SUBSTANCE: methods for express analysis of the group composition of bitumen, which consists in the simultaneous registration of the decay signal of free induction and the envelope of echo signals in the Carr, Purcell, Meiboom, Gill sequence. A method for determining the group composition of bitumen in rock using low-frequency NMR relaxometry is disclosed, which consists in taking a sample of bitumen-saturated rock and crushing it to grains with a diameter of not more than 5 mm, then the ground sample is dried at a temperature T = (60±0.2)°C for 12 hours with the possibility of ensuring the removal of residual water, then the prepared sample is placed in a test tube with the possibility of ensuring maximum filling in the area of the measuring coil of the NMR analyzer, then the test tube with the sample is thermostatically controlled, then the NMR analyzer is adjusted, while measuring two free induction decay signals and the envelope of the echo signals in the Carr-Purcell-Meiboom-Gill sequence, performed in parallel on the NMR analyzer, the measurement parameters are entered, then the results are mathematically processed, which consists in fitting the experimental free induction decays and the decay envelope in the series Carr, Purcell, Meiboom, Gill sequence; then, from the envelope of the echo signals in the Carr-Purcell-Meiboom-Gill sequence, the amplitudes of the liquid-phase components are determined, then the relative content of each component is determined as the ratio of the corresponding amplitude to the total amplitude, the asphaltene content is determined from the free induction decay signal as the ratio of the amplitude of the solid-phase signal to the total amplitude with obtaining the parameters of the group composition of the bitumen in the rock.

EFFECT: rapid determination of bitumen group composition in rock samples; exclusion of complex and lengthy sample preparation operations; exclusion of the extraction process; exclusion of multi-stage chemical analysis; exclusion of the use of any reagents and solvents; improving the manufacturability of the analysis of bitumen in the rock.

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