METHOD FOR DETERMINING AMOUNT OF KEROGEN AND EXTRACTED BITUMEN IN ROCK USING NMR RELAXOMETRY Russian patent published in 2024 - IPC G01N24/08 

FIELD: measuring.

SUBSTANCE: invention can be used for determination of quantitative content of kerogen and bitumen in rock by means of NMR relaxometry. Essence of the invention consists in the fact that a rock sample is taken in the form of one or more pieces of rock or a core in the form of a cylinder with diameter of 8.5 mm and height of 13 mm; further, the rock sample is placed in a pre-weighed glass test tube with diameter of 10 mm to height of 13 mm with the possibility of providing maximum filling in the resonance region of the measuring coil of the NMR relaxometer; further, the test tube with the sample is weighed; further, the weight of the sample is determined from the difference in the masses of the filled and empty test tube; further, the test tube with the sample is thermostated for at least 15 minutes at temperature of 40±0.2 °C; then performing the NMR relaxometer adjustment and starting the measurement process, as a result of which the free induction decay signal is recorded with a minimum "dead time" equal to 10 microseconds; then performing mathematical processing of results, then determining total content of organic substance OM, then filling a test tube with a solvent sample, which does not contain hydrogen atoms, namely deuterated chloroform CDCl₃ or carbon tetrachloride CCl₄, to height of 15 mm, so as not to go beyond limits of resonance area of the measuring coil of the NMR relaxometer, and the test tube is closed with a sealed plug; then the test tube with the sample is placed for 24 hours in a drying cabinet at temperature of 40±0.2 °C; further, the NMR relaxometer is adjusted, then the test tube with the prepared sample is placed in the NMR relaxometer and the measurement process is started, as a result of which a free induction decay signal is recorded with a minimum "dead time" equal to 10 mcs; then performing mathematical processing of results and determining the amplitude of liquid components of the sample A_L0; then the test tube with the sample is placed again for 24 hours in a drying oven at temperature of 40±0.2 °C and repeating the process of measuring and evaluating the amplitude of the liquid components of the sample A_L0 until A_L0 ceases to increase, which indicates complete extraction of bitumen from the rock sample; then, total portion of kerogen N_kerogen and total portion of extracted bitumen N_bitumen in the sample are calculated.

EFFECT: enabling determination of the amount of kerogen and extracted bitumen in the rock without preliminary chemical preparation and treatment of the analysed samples.

1 cl, 2 dwg, 2 tbl