Hydrogeophysical methods for analyzing aquifer storage and recovery systems.

Area of Science:

• Hydrogeology
• Geophysics
• Environmental Engineering

Background:

• Aquifer Storage and Recovery (ASR) systems are crucial for water management, but effective siting and monitoring remain challenging.
• Understanding subsurface responses to ASR operations is key to optimizing system performance and sustainability.

Purpose of the Study:

• To develop and validate hydrogeophysical methods for siting and monitoring ASR systems.
• To provide a quantitative framework for selecting optimal geophysical techniques and data acquisition strategies for ASR projects.
• To simulate and assess the geophysical response to freshwater injection into a saline aquifer.

Main Methods:

• Numerical simulations of coupled fluid flow and solute transport in a Dammam aquifer model.
• Calculation of bulk geophysical properties from petrophysical relationships.
• Simulation of dynamic geophysical responses using electrical resistivity, time-domain electromagnetic (TEM), and seismic methods.
• Investigation of sensitivity to aquifer heterogeneity, dispersivity, and confining layer permeability.

Main Results:

• The study successfully simulated the geophysical response to ASR operations, including changes in fluid salinity and pressure.
• Electrical resistivity, TEM, and seismic methods showed varying sensitivities to subsurface property changes during ASR.
• The framework allows for quantitative assessment of site-specific geophysical monitoring strategies.

Conclusions:

• Hydrogeophysical methods, when integrated with flow and transport simulations, offer a powerful tool for ASR system management.
• The presented simulation strategy enables the optimization of geophysical monitoring for ASR projects.
• This approach supports informed decision-making in the siting and operational phases of ASR systems.