Changes

Water drive recovery increases with the strength of the aquifer if water production can be minimized. As with gas cap drive reservoirs, this is done most easily in reservoir geometries that allow wells to be perforated a considerable distance from the fluid contact.

Water drive recovery increases with the strength of the aquifer if water production can be minimized. As with gas cap drive reservoirs, this is done most easily in reservoir geometries that allow wells to be perforated a considerable distance from the fluid contact.

Water drive recovery also depends on the aquifer's sweep efficiency. ''Sweep efficiency'' is a measure of how effectively the encroaching water displaces oil. Higher sweep efficiencies and oil recoveries occur when the viscosity of the oil is low compared to that of the water and oil flows more easily than the encroaching water. Water drive reservoirs with high viscosity crudes have lower sweep efficiencies and oil recoveries because the water tends to move ahead of or “finger” through the oil, leaving behind unswept oil.

Water drive recovery also depends on the aquifer's sweep efficiency. ''Sweep efficiency'' is a measure of how effectively the encroaching water displaces oil. Higher sweep efficiencies and oil recoveries occur when the [[viscosity]] of the oil is low compared to that of the water and oil flows more easily than the encroaching water. Water drive reservoirs with high viscosity crudes have lower sweep efficiencies and oil recoveries because the water tends to move ahead of or “finger” through the oil, leaving behind unswept oil.

Water drive recovery can be improved by balancing production rates across the field so that the oil-water contact moves up as uniformly as possible. Since water drive is usually more efficient than solution gas drive, in some cases it is possible to increase recovery by producing the reservoir at a rate low enough that the aquifer is able to maintain a high reservoir pressure.

Water drive recovery can be improved by balancing production rates across the field so that the oil-water contact moves up as uniformly as possible. Since water drive is usually more efficient than solution gas drive, in some cases it is possible to increase recovery by producing the reservoir at a rate low enough that the aquifer is able to maintain a high reservoir pressure.