Forecast of changes in the hydrodynamic regime of the Metegero-Ichersky aquifer complex during the operation of the Internatsionalnaya pipe (Western Yakutia)

Abstract

Introduction: during the operation of the Internatsionalnaya pipe, a significant increase in groundwater inflows to the mine field is predicted from the current 10-15 m³/hour to 1000 m³/hour in 2027, associated with the opening of the Icherskaya suite collectors. An increase in the inflow to the mine field of the deposit will require multiple intensification of the reinjection process, currently implemented in the collectors of the Metegero-Icherskaya aquifer complex within two areas located in the zone of dynamic influence of the regional Western fault. The adopted technical solutions will affect the hydrodynamic regime of the studied aquifer complex. Forecasting the hydrodynamic regime is an important component of ensuring the environmental safety of the reinjection process, in terms of determining the boundaries of the repression spreading dome, as well as timely response to the creation of an excess pressure front.

Methodology: the main forecasting method was hydrogeological modeling. When constructing the hydrodynamic model, the hydrogeological characteristics of the Metegero-Ichersky aquifer complex were detailed. The initial parameters of the complex were adopted based on the materials of previously completed pilot and research work for the entire period of field development and were adjusted at the stage of model calibration. The forecast of changes in the hydrodynamic regime was carried out using the Feflow hydrogeological modeling program.

Results and discussion: new information was obtained on local changes in the hydrodynamic regime of the Metegero-Ichersky aquifer complex. Maps and diagrams of piezometric surfaces are presented, the development of a depression funnel and an imposed repression spreading dome is traced. By 2029, the piezometric surface of the Metegero-Ichersky aquifer complex will acquire a dipole appearance, the depression funnel around the Internatsionalny mine will coincide with the repression spreading dome from the Western fault. In the future, the piezometric surface of the aquifer will not undergo significant changes.

Conclusion: the implementation of hydrodynamic and hydrogeological calculations made it possible to estimate the predicted total productivity of injection sites taking into account the current state of injection wells, as well as to forecast the availability of the need for handling drainage waters of the Internatsionalny mine. The predicted piezometric surface marks obtained as a result of modeling make it possible to predict the possibility of further injection of drainage brines into the Metegero-Ichersky aquifer complex.