Gravity gradiometry difference measurement as a tool for monitoring pumping and injection; forward modeling results
- Department of Energy, Idaho Falls, ID (United States)
- Lockheed Martin Idaho Technologies Company, Idaho Falls, ID (United States)
Gravity gradiometry forward models have been developed at the Idaho National Engineering and Environmental laboratory (INEEL) that can characterize gravity gradient changes with the development of a cone of depression or injection mound in water table aquifers. Difference measurements at long time intervals reduce delayed drainage effects and eliminate the need for determining an initial density structure. Qualitative or semi-quantitative analysis of the gradient signal to determine changes in groundwater distribution with injection or pumping may be possible, particularly if the time varying nature of the signal is of interest. Gravity gradiometer instruments (such as the Gravity Gradient Survey System) have progressed to the point where the complete second order gravity gradient tensor can be measured with an instrument noise level of less than 1 Eotvos (0.1 microgals/meter). Modeling indicates direct gravity measurements for the injection mound perched aquifier case could produce similar signal to noise ratios. However gravity gradients provide 5 independent measurements and due to the common mode nature of the instruments are less susceptible to other effects (tide, latitude, elevation, etc.). The gradients also provide a sharper image of the edge of the anomaly. The systematic identification and removal of specific retention, rainfall and subsidence or uplift effects may be required to make gradiometry difference imaging practical for field use.
- Research Organization:
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- USDOE Office of Environmental Restoration and Waste Management, Washington, DC (United States)
- DOE Contract Number:
- AC07-94ID13223
- OSTI ID:
- 542035
- Report Number(s):
- INEL/CON-97-00292; CONF-9703120-; ON: DE97053250; TRN: 98:008445
- Resource Relation:
- Conference: 32. annual symposium on engineering geology and geotechnical engineering, Boise, ID (United States), 26-28 Mar 1997; Other Information: PBD: 1997
- Country of Publication:
- United States
- Language:
- English
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