The pilot-industrial works to introduce new equipment – the GeoSpec NMR spectrometer of modification 2/53 were carried out in Tyumen branch of SurgutNIPIneft in 2016. The results of measurements on samples of different lithologic types of rocks from all areas of work of Surgutneftegas OJSC are considered. The description of the GeoSpec device of modification 2/53 and features of its operation is given.
The use of the NMR spectrometer to determine the effective porosity allowed to accelerate the process of evaluating the effective porosity, to conduct studies on irregularly shaped samples, including boring sludge. The method made it possible to study samples, saturated as by the formation water model, and kerosene. With the correct adjustment of the instrument, the saturating liquid did not affect the accuracy of determining the total and effective porosity.
Analysis of the results of the performed studies has shown the possibility of working with terrigenous, carbonate and volcanogenic rocks. Pre-adjustment of the technique on standard samples is required for each type of rock. The use of standard time cutoffs reduces the accuracy of determining the effective porosity and can only be used for a rough estimate of the effective porosity in the intervals of the broken core recovery. This approach can also be implemented to interpret the results of the sludge investigation when core sampling is not performed. Preliminary setting of the time cutoffs at comparing the results with the data obtained using the standard method for determining the effective porosity, increase the accuracy of the effective porosity estimation.
The results of the use of the NMR spectrometer to evaluate the effective porosity indicate a high reliability of the method and an extended field of application in comparison with the standard procedure.
References
1. Coates C., Xiao Lizhi, Prammer M.G., NMR logging principles and applications, Houston: Halliburton Energy Services, 1999, 335 p.
2. GeoSpec 2-53: User manual V. 1.8. Oxford instruments magnetic resonance, Abingdon: Industrial Analysis, 2013, 34 p.
3. Tikhonov A.N., On ill-posed problems of linear algebra and a stable method for their solution (In Russ.), DAN SSSR = Doklady Mathematics, 1965, V. 163, no. 3, pp. 591–594.
