Page 194 - Principles of Applied Reservoir Simulation 2E

Part II: Reservoir Simulation 179

model calculated rates. If the history of reservoir performance is extensive, then
it is often wise to place a greater reliance on the validity of the most recent field
data when performing a history match.
Phase ratios, such as GOR and WOR, are sensitive indicators of model
performance. Matching ratios provides information about pressure depletion and
front movements. Tracers are also useful for modeling fluid fronts. Tracers need
not be expensive chemicals; they can even be changes in the salinity of produced
water. Salinity changes can occur as a result of mixing when injected brine and
in situ brine have different salinities. Water sample analysis on a periodic basis
is useful for tracking salinity variation as a function of time.

Time-Lapse Seismic History Matching
An emerging history matching strategy is to combine time-lapse seismic
reservoir monitoring with traditional flow modeling in a process referred to as
seismic history matching [Lumley and Behrens, 1997]. Seismic history matching
is an iterative process, as illustrated in Figure 18-1.The ovals in the figure
represent model preparation, while the rectangles correspond to the history
matching process.

Update Reservoir Model
Make Reservoir Management Compare with
Decisions 4D Seismic Data
A
V
/^^ ^"N. f Seismic
f Reservoir \ ( Modeling
V Modeling ) X^ Imaging

Rock Physics
Elastic Properties

Figure 18-1. Seismic history matching [after Lumley and Behrens,
SPE 38696, 1977].