Vol 2 Chapter 22: Hyperspectral Geobotanical Remote Sensing for CO2 Storage Monitoring
William L. Pickles and Wendy A. Cover
Abstract: This project has developed an airborne remote sensing method for detection and mapping of CO2 that might be leaking up from an underground storage formation. The method uses high-resolution hyperspectral imagery to detect and map the effects of elevated CO2 soil concentrations on the roots of the local plants. The method also detects subtle or hidden faulting systems which localize the CO2 pathways to the surface. Elevated CO2 soil concentrations deprive the plant root systems of oxygen which is essential for a healthy plant. Excessive soil CO2 concentrations are observed to significantly affect local plant health, and hence plant species distributions. These effects were studied in a previous remote sensing research program at Mammoth Mountain, CA, USA. This earlier research showed that subtle hidden faults can be mapped using the spectral signatures of altered minerals and of plant species and health distributions. Mapping hidden faults is important because these highly localized pathways are the conduits for potentially significant CO2 leaks from deep underground formations. The detection and discrimination methods we are developing use advanced airborne reflected light hyperspectral imagery. The spatial resolutions are 1–3 m and 128 band to 225 wavelength resolution in the visible and near infrared. We are also using the newly available “Quickbird” satellite imagery that has spatial resolutions of 0.6 m for panchromatic images and 2.4 m for multispectral. These are two commercial providers of the hyperspectral imagery acquisitions, so that eventually the ongoing surveillance of CO2 storage fields can be contracted for commercially. In this project we had a commercial provider acquire airborne hyperspectral visible and near infrared reflected light imagery of the Rangely, CO enhanced oil recovery field and the surrounding areas in August 2002. The images were analyzed using several of the methods available in the suite of tools in the “ENVI” commercial hyperspectral image processing software to create highly detailed maps of soil types, plant coverages, plant health, local ecologies or habitats, water conditions, and man-made objects throughout the entire Rangely oil field and surrounding areas. The results were verified during a field trip to Rangely, CO in August 2003. These maps establish an environmental and ecological baseline against which any future CO2 leakage effects on the plants, plant habitats, soils and water conditions can be detected and verified. We have also seen signatures that may be subtle hidden faults. If confirmed these faults might provide pathways for upward CO2 migration if that occurred at any time during the future.
Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO2 Capture
Project Geologic Storage of Carbon Dioxide with Monitoring and Verification - Volume 2
Edited by: Sally M. Benson, Lawrence Berkeley Laboratory, Berkeley, CA, USA
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