Features of hydrogeologic wells design: the case of the Levoberezhny site for burial of drainage brines of the Udachnaya pipe deposit

The article is devoted to the study of the design features of hydrogeological wells at the Levoberezhny site, intended for the burial of drainage brines from the Udachnaya pipe deposit in permafrost conditions in Western Yakutia. The relevance of the work is due to the need to minimize the negative impact of diamond mining on the fragile ecosystem of the cryolithozone. The main attention is paid to the problem of utilization of calcium chloride brines, which have a devastating effect on the stability of rocks and mining equipment. The article presents the results of drilling 8 wells with a depth of 300 m, performed using a mobile drilling rig UKB-5S. Drilling methods are described, including rotary and impact-rotary drilling using compressed air as a cleaning agent, which made it possible to achieve a core yield of at least 80 %. The design of wells is considered in detail, including casing fastening and cementing the annular space to ensure the stability of the trunks under the influence of brines. Special attention is paid to technological solutions, such as the use of perforated columns with slit filters to prevent rock collapses and thawing. The hydrogeological studies carried out, including the methods of bush filling, have confirmed the high absorption capacity of fractured permafrost rocks, which makes the Levoberezhny site suitable for the disposal of drainage waters. The results of the work have shown that the developed well design and applied drilling technologies ensure the stability and durability of wells in difficult geological conditions. The data obtained can be used for further pilot production and predictive calculations aimed at safe and efficient disposal of drainage brines.