Date of Award

2022

Document Type

Open Access Master's Report

Degree Name

Master of Science in Geological Engineering (MS)

Administrative Home Department

Department of Geological and Mining Engineering and Sciences

Advisor 1

John S. Gierke

Committee Member 1

Eric Seagren

Committee Member 2

Nathan D. Manser

Abstract

Temporally, the KBIC (Keweenaw Bay Indian Community) Hatchery wells have manifested general trends of declining specific capacity and higher energy consumption due to mineral precipitation in and around the production wells. Monitoring data, laboratory water analyses, and downhole video logging have confirmed that naturally occurring minerals are precipitating and clogging the screens and, likely, the surrounding formations. The reduction in fluid pressures in and around the well-screens from active pumping wells is typical but, ultimately alters the geochemical and physical conditions such that dissolved minerals precipitate on and around the well-screens, therefore, effectively clogging the well. The clogging from mineral precipitation results in increased drawdown causing more pressure losses and clogging, and so on. Consequently, the pumps work harder and ultimately increase energy consumption and reduce production efficiencies.

The Hatchery’s SCADA system now provides the ability to monitor flows and drawdowns, which reflect important information regarding well field performance. To be more economically strategic in managing the well field operations it is apparent that the performance data from the SCADA system must be utilized to conserve well-field-related costs. The analysis of the SCADA data clearly shows that the production well’s performance diminishes with use over time due to well-screen plugging because of mineral precipitation in and around the well-screen. The observed regained performance from well rehabilitation efforts (mechanical scrubbing and/ or acid treatment) demonstrates their effectiveness, and with the use of the spreadsheet tool (developed for the KBIC Hatchery production well field), the frequency of rehabilitation efforts can be assessed on a more financially sound basis by forecasting a relative breakeven cost-benefit analysis for a particular well and associated rehabilitation. The economic analysis of power consumption and treatment costs suggests that well-treatment costs can be recovered in approximately 6-9 years based on the treatment's effectiveness in offsetting the performance declination due to mineral precipitation from pumping and relative drawdown. In other words, the magnitude of the regained well performance will be proportional to the rehabilitation method’s effectiveness in removing the mineral precipitation buildup and unclogging the well screen. The SCADA system is invaluable for monitoring, understanding, and managing the well field. The continued use of the SCADA system and implementation of the other recommendations in this report will be financially beneficial as more informed flow-management decisions can be made with confidence. Furthermore, to improve life on our planet through more sustainable approaches to groundwater management, the continued development of computational tools that utilize field monitoring data in making strategic decisions for well rehabilitation and minimizing drawdown will be essential for groundwater optimization and energy cost reduction now and in the future.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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