Basic Research Needs for Geosciences - Energetics Meetings and ...

GRAND CHALLENGE:INTEGRATED CHARACTERIZATION, MODELING, AND MONITORING OF GEOLOGIC SYSTEMSFigure 32. Example of the use of time-lapse crosshole seismic velocity information and petrophysical relationshipsto estimate percent of CO 2 saturation associated with injection of CO 2 into a brine reservoir at the Frio Pilot StudySite in Texas (Daley et al. 2007). The estimated saturation values obtained using 2D, time-lapse seismic datasetsagreed favorably at the wellbore location with the CO 2 concentration information obtained using the Schlumbergerreservoir saturation tool (RST).of remote methods for informing us about transformations associated with manipulations,significant research on petrophysics, fusion, joint inversion, resolution and scaling is needed toadvance these monitoring approaches to a level where they can be used to interrogate subsurfacesystem responses to perturbations.Seismic interferometrics have been shown to be a highly sensitive monitoring tool (Snieder et al.2002). It also has been shown that the response of a system can be retrieved from ambientfluctuations (Curtis et al. 2006). This obviates the need for using active sources for monitoringpurposes. A combination of these two approaches has been used for daily monitoring ofvolcanoes and fault zones (Sens-Schonfelder and Wegler 2006; Wegler and Sens-Schonfelder2007). This methodology has been implemented so far only for seismic approaches, but can inprinciple be extended to a large class of physical systems that includes coupled processes(Wapenaar et al. 2006) such as the seismo-electric effect.Coupled monitoring and modeling approachesIterative comparison of time-lapse information and advanced simulations can be used to improveboth monitoring and modeling approaches. For example, advanced monitoring data can be usedto constrain, update or validate modeling approaches, and monitoring predications can be used toreduce the uncertainty associated with the interpretation of system transformations using indirectdatasets, such as time-lapse geophysical data (e.g., Hubbard et al. 2007).Basic Research Needs for Geosciences: Facilitating 21 st Century Energy Systems 87