Assessing Technical and Economic Recovery of Oil Resources

Figure 8, Effects of High Hydrodynamic Flow on OWC Tilt, on the other hand,shows much more pronounced changes in the OWC, TZ and ROZ of the reservoirfollowing the initiation of a higher, more representative aquifer flow rate of 1 foot peryear. The result is a larger ROZ and a diminished main pay zone.Using aquifer flow of 1 foot per year and a higher horizontal permeability (50 md),Figure 9, Effects of Aquifer Permeability on OWC Tilt, leads to the creation of a moremodest ROZ compared to the previous case (shown in Figure 8). This indicates thathigh horizontal permeability will decrease the hydrodynamic interaction between theaquifer and the oil column, suppressing the size of the ROZ.Increasing the vertical to horizontal permeability ratio (kv/kh) to 1 (Figure 10,Effects of High Kv/Kh on OWC Tilt) does not appreciably change the final oil and watercontact tilts, as compared to Figure 8. However, decreasing the vertical to horizontalpermeability ratio to 0.01 creates an S-shaped OWC, with a very pronounced ROZ nearthe flow source and a subtle ROZ along the middle of the cross-section, Figure 11,Effects of Low Kv/Kh on OWC Tilt. A longer than 2,000 year hydrodynamic flow periodwould likely change the shape of this ROZ wedge, creating a much steeper TZ/ROZinterface.2-9 February 2006