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 waterconductivity of an aquifer. Methods for determining water conductivity are primarily designed forhomogeneous aquifers. However, natural hydrogeological objects are often heterogeneous, whichcan complicate the interpretation of experimental data from hydrodynamic studies and lead toerrors in calculating groundwater reserves. The article shows the impact of rock filtration hetero-geneity on reserve calculation forecasts. The studies, including hydrodynamic testing (clusterpumping), 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 wereinterpreted using the Theis model. The parameters of the aquifer are determined: coefficient ofwater conductivity and pressure conductivity factor. The article presents predictive calculations forthe reduction of water levels in the center of a large well. The forecast was conducted for threeoptions, 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 calculationerror 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 filtrationheterogeneity to obtain reliable field parameters. This will cover the disturbance of an aquifer with alarger size than the filtration heterogeneity of rocks.