FIELD: measurement technology.
SUBSTANCE: method involves extracting and drying sample, saturating it with water and measuring nuclear magnetic resonance characteristics. Reference rock samples are prepared in advance characterized by known water content in pores (R1) and known wettability (R2). Capillary soaking of a sample under test and of R2 samples is carried out. Nuclear magnetic resonance signal amplitude and longitudinal and transverse relaxation speed in water are measured in given time interval. Nuclear magnetic resonance signal amplitude is measured in R1 samples. Calibration relationship is built for signal amplitude against water volume content in R1 samples. Water saturation coefficient of these samples and complex relaxation parameter are determined from measured signal amplitude values for sample under test and R2 samples with calibration plot being used. The complex relaxation parameter is calculated from expression like W=α(1/T2-1/T1), where α is the sample water saturation coefficient after capillary soaking in given time interval; 1/T2, 1/T1) are the longitudinal and transverse relaxation speed values in the sample. Then, calibration relationship is built for wettability against complex relaxation parameter for reference R2 samples. The calibration relationship is used for determining wettability of rock sample under study from complex relaxation parameter value.
EFFECT: high reliability and accuracy of parameter determination.
2 dwg
