Quantitative Monitoring of Fluid Saturation Changes Using Cased-Hole Logs


D. E. Fitz, N. Ganapathy,
Exxon Production Research Company

SPWLA 34th Annual Logging Symposium, June 13-16, 1993



Reservoir engineering studies have indicated that gas–drive/gravity–drainage recovery efficiency is about 80% compared to 60% for waterflood/gravity-drainage. A residual oil saturation study using core samples determined that immiscible gas-drive recovery of the water-flooded sands in the reservoir should reduce remaining oil saturation an additional 10 su below the waterflood residual value of 18 su. A field test of the immiscible gas-drive process was begun in the unit with the immiscible gas being over-injected to invade previously water-flooded sands. This same type of process has been used in other fields and has been called the Double Displacement Process (Carlson, 1988).