A digital database of the waterflooded oil reservoirs in Illinois was created as part of the DOE PUMP II program (Contract DE-FC26-02NT15132) to develop geographic information system-based (GIS) play portfolios to improve oil production in the Illinois Basin. The database was compiled from data on paper forms that are submitted annually to the Illinois State Geological Survey (ISGS) by petroleum operators. Attributes collected from the forms include annual and cumulative oil production, water injection and water production. Detailed oil reservoir information such as reservoir pressure, porosity, permeability, API gravity of the oil and depth of the waterflooded horizons are also submitted.

To help producers identify underdeveloped areas in existing oil fields, a strategy was devised and implemented to transfer the digital databases, data manipulation methods and GIS map layering capabilities to petroleum operators through an internet mapping server (IMS). Color coded pay maps and waterflood unit maps were used to identify horizons and units that are currently being waterflooded or were waterflooded in the past. The layering capabilities of the ILoil ArcIMS website could then be used by operators to locate potentially overlooked or bypassed reserves. This database should be available in late fall of 2004.

Using data available in the newly created database, we have used traditional waterflood and reservoir surveillance tools to compare oil reservoir responses in 3 Mississippian Reservoirs. The primary means for making comparisons between waterflooded units is the recovery plot and the recovery derivative. Representative decline curves and oil recovery curves are developed on a per unit/formation basis. These tools are designed to assist in a "first pass" assessment of individual waterflood patterns within a unit or a unit to unit comparison within a field.

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