The impact of rock filtration heterogeneity on fresh groundwater reserve prediction calculations in the Nefteyuganskoye field

Abstract

In hydrogeology, filtration heterogeneity of rocks usually means heterogeneity of water
conductivity of an aquifer. Methods for determining water conductivity are primarily designed for
homogeneous aquifers. However, natural hydrogeological objects are often heterogeneous, which
can complicate the interpretation of experimental data from hydrodynamic studies and lead to
errors in calculating groundwater reserves. The article shows the impact of rock filtration hetero-
geneity on reserve calculation forecasts. The studies, including hydrodynamic testing (cluster
pumping), were carried out at the Nefteyuganskoye field, which is one of the major fresh ground-
water deposits of the Latitudinal Ob region. The experimental data from four experiments were
interpreted using the Theis model. The parameters of the aquifer are determined: coefficient of
water conductivity and pressure conductivity factor. The article presents predictive calculations for
the reduction of water levels in the center of a large well. The forecast was conducted for three
options, taking into account the filtration heterogeneity of the aquifer in the field. Consequently,
the impact of filtration heterogeneity on the forecast calculations was determined. The calculation
error in estimating groundwater reserves at the Nefteyuganskoye field could be as high as 51 %.
The article suggests conducting long-term hydrodynamic studies in subsurface areas with filtration
heterogeneity to obtain reliable field parameters. This will cover the disturbance of an aquifer with a
larger size than the filtration heterogeneity of rocks.