As part of a small scale sequestration test (about 1500 tonsof CO2) in a saline aquifer, time-lapse borehole seismic surveys wereconducted to aid in characterization of subsurface CO2 distribution andmaterial property changes induced by the injected CO2. A VSP surveydemonstrated a large increase (about 75 percent) in seismic reflectivitydue to CO2 injection and allowed estimation of the spatial extent of CO2induced changes. A crosswell survey imaged a large seismic velocitydecrease (up to 500 m/s) within the injection interval and provided ahigh resolution image of this velocity change which maps the subsurfacedistribution of CO2 between two wells. Numerical modeling of the seismicresponse uses the crosswell measurements to show that this small CO2volume causes a large response in the seismic reflectivity. This resultdemonstrates that seismic detection of small CO2 volumes in salineaquifers is feasible and realistic.

Map of the Environmental Learning Center at Sheldon Lake State Park showing ponds, trails, points of interest, and park buildings. There is a small map showing the location of the center within the park to the left of the main map, and a detailed view of Heron Plaza to the right of the main map. The back of the map has text descriptions of numbered points of interests at the center.

A guide to the rules for maintaing air quality in businesses with machinery that generates large quantities of heat in the Houston, Galveston, and Brazoria areas.