In the fifth quarter of this DOE NETL project, they have implemented an algorithm that inverts for changes in fluid properties over time using time-lapse seismic anomalies. This algorithm constitutes the second step in the inversion procedure for Phase III of the project. They demonstrate this inversion procedure with a synthetic data example. Additional activities in this reporting period include a trip by the Principal investigator to an International Monitoring Workshop sponsored by the IEA Greenhouse Gas R and D Program in Santa Cruz, California. In the next quarter, they will further process the Sleipner data to prepare it for later inversion, and continue investigating alternative methods for calculating properties of oil/brine/CO{sub 2} systems.