The Lammont-Doherty Earth Observatory at Columbia University is leading a team of researchers studying the possibility that offshore Gulf Coast oil reservoirs are being "recharged" by oil flowing upward through fault zones. The possibility of active recharging of oil reservoirs is evident in production histories from tracts in the study area. The DOE cost-shared field demonstration is providing insights into new ways to produce oil reservoirs deep below the salt formations underlying the Gulf of Mexico. Data from the research could reveal how some oil reservoirs are filled in the Gulf and other similar basins. The focus is on "growth faults," structural pathways leading from deep oil sources upward to shallower reservoirs. While conventional petroleum geology measures the rate of upward migration of hydrocarbons from their deep sources in hundreds of thousands of years, the Lamont-Doherty researchers are detecting evidence that oil may be flowing to shallower reservoirs much more rapidly through these growth faults, perhaps in only decades. If this geologic model is accurate, it may mean that certain reservoirs are actually being replenished during their productive life. This could lead to recovery of more oil than one-time "snapshot" estimates would indicate. Equally important is the potential for producers to use growth faults as shortcuts to tap deeper hydrocarbon accumulations. Seismic modeling technology in four dimensions-multiple 3-D seismic surveys conducted over a period of years-has been developed in this project to locate areas in which fluid migration is replenishing reservoirs or oil bearing areas that are not being depleted by the existing wells. The firs well drilled as a result of the 4-D seismic technology initially produced 1500 barrels per day. This well will provide federal royalties worth the full project value within five years (any tax benefits are additional). Because of the huge potential benefit of this technology, an industry consortium is funding post-project refinements of the 4-D technology.