Seismic Attribute Processing to Find Deep Aquifers
Seismic reflection surveys collect data on the propagation of seismic waves to depths of several thousand feet. Developed by the oil and gas industry, seismic data can be used to map structural features in fine detail. Modern processing and interpretation techniques can map aquifer units, faults, and other structural features that can control well yield. With a little more processing, the shape of the waveforms can identify changes in the stratigraphy, porosity, and pore fluid characteristics in a unit. Seismic attribute processing can be used to identify permeable features such as narrow channel sand deposits at depths of thousands of feet to target permeable zones.
The cost to acquire reflection data is relatively high, which has limited the application of the method for water supply applications. Fortunately many areas have libraries of existing reflection data from previous oil and gas exploration activities. This data can often be purchased for a few thousand dollars per mile and used to map units that can potentially serve as aquifers.
Several case histories will be presented to demonstrate how modern interpretation methods can be used on 2D or 3D seismic reflection data to map features such as sand channels, faults, and pinch outs in aquifer units and direct drilling programs toward higher yielding sites.