The Use of Shallow Subsurface Wells and Collected Multi-offset VSP for Characterizing the Black Warrior Basin
Harris, Whitney C.; Goodliffe, Andrew M.; Pashin, Jack
The use of shallow subsurface wells for monitoring events is a new and upcoming field for geophysical exploration. At the William C. Gorgas Plant in the Black Warrior Basin three 300 foot wells were drilled to record active and passive sources that include vibroseis, a drill bit, and a naturally occurring event. These data are being used to create a 1D velocity model from the primary events that will then be modified from modeling secondary arrivals to compensate for lateral variations including anisotropic parameters. The interpretations from this project will then be applied to a larger scale project that evaluates multi-offset Vertical Seismic Profiles (VSPs) for shear wave splitting that may be due to vertical fractures and joint sets, rather than interlaying shale beds. These anomalies have been noted in the zero-offset VSP, which will be used for creating the first synthetic model of the area directly around the borehole. This model will then be cross referenced with the other multi-offset VSPs further away from the main wellbore and then the model will be validated with interpretations from a Formation MicroLog Imager (FMI).
Together, these two studies will help characterize the subsurface for carbon sequestration. Once the subsurface is further investigated the feasibility of potential future projects, including CO2 injection in conjunction with enhanced oil recovery, will be determined.
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013