On the issue of determining the porosity of terrigenous reservoirs of deposits of natural bitumen and super-viscous oils

Abstract

© 2020 Saint Petersburg 2020 - Geosciences: Converting Knowledge into Resources. All rights reserved. This work relates to the problem of determining porosity in the terrigenous super-viscous oil reserves. Lithological-facies variability is observed in the reservoir, porosity values vary widely (from 8% to more than 30%), lithological differences are represented by both sandstones and weakly consolidated sands. The work used the data of laboratory core studies and geophysical well surveys (formation density logging, acoustic and neutron logging). A comparative analysis of porosity methods with core data did not show satisfactory approximation confidence values. The results of this analysis also revealed that core samples are grouped by porosity according to the following criteria: porosity of less than 15%, from 15 to 20% and more than 20%. The application of acoustic impedance allowed us to obtain positive dynamics in the study. The product of formation density and velocity in comparison with porosity from core data showed a satisfactory petrophysical function. An increase in porosity in the samples with a decrease in the values of acoustic impedance became apparent obviously. In addition, this is the only group of methods under consideration that showed not a chaotic, but a regular change in porosity (all selected classes are clearly grouped). One of the advanced planning of solving the problem of determining the filtration-capacitive parameters is the volume modeling of the reservoir based on the acoustic characteristics of rocks.