Model of well clogging during in situ groundwater deironing

Summary

The study focused on the evolution of aquifer porosity during operation of in situ groundwater treatment systems at a water intake facility in the Russian Far East. The objective was to evaluate precipitate distribution and changes in aquifer hydraulic conductivity within the near-wellbore zone. Predictive simulations of precipitate accumulation were performed. The resulting additional drawdown, as well as reductions in permeability and porosity of the near-filter formation, were assessed. The precipitation zone develops directly adjacent to the well at the injected oxygen concentration of 12.5 mg/l. Simulations show that precipitate accumulation near the well caused an additional drawdown of approximately 5 m and reduced the specific capacity of the well. Coupled groundwater flow and geochemical models of well clogging were developed. The models account for variable permeability and porosity controlled by the volume of deposited iron oxides.

Key words

filter , iron , permeability , well , porosity , filtration of coefficient , injection , pumping , precipitate accumulation , oxidation kinetics , oxygen

Developing biopolymer drilling mud for water supply well construction

Summary

The results of experimental studies of the effect that different drilling mud compositions produce on the colmatage of a bottom-hole zone are presented. The studies aimed at developing process liquids that preserve the reservoir properties and ensure environmentally safe construction and operation of water supply wells. The use of traditional slurries causes pollution of both the reservoir and bottom-hole zone. The efficient stabilization of the reservoir properties is ensured by the use of non-dispersing biopolymer drilling mud with the addition of acid-soluble sealant that prevents the invasion of filtrate and drilling mud into reservoir, bottom-hole zone, and preserves at most their collecting properties (for 70–80%).

Key words

water well , colmatage , bottom-hole zone , reservoir properties , permeability , drilling mud