Other MBAL Models
Material Balance:
This incorporates the classical use of Material Balance calculations for history matching through graphical methods (like Havlena-Odeh, Campbell, Cole etc.). Detailed PVT models can be constructed (both black oil and compositional) for oils, gases and condensates. Furthermore, predictions can be made with or without well models and using relative permeabilities to predict the amount of associated phase productions.
MBAL can also be tied into GAP for integrated production modelling studies, providing an accurate and fast reservoir model as long as the assumptions of material balance are valid for the real situation to be modelled.
Reservoir Allocation:
When a well is producing from multiple layers, it is essential for an engineer to know how much each layer has contributed to the total production. Traditionally, this reservoir allocation has been done based on the kh of each layer. This approach does not take the IPR of the layers into account and also ignores the rate of depletion of the layers.
The Reservoir Allocation tool in MBAL improves the allocation by allowing the user to enter IPRs for each layer and calculates the allocation by taking the rate of depletion into account as well. Crossflow is also accounted for in the model, as well as different start/finish times for the wells. Impurities are also tracked and can provide an effective measure of the quality of the underlying assumptions in the case where few data is available.
Monte Carlo Simulation:
This tool enables the user to perform statistical evaluation of reserves. Distributions can be assigned to variables like porosity or thickness of the reservoir and the program will generate the range of probabilities associated with a reserves range.
Decline Curve Analysis:
Production data can be fitted to Hyperbolic, Exponential or Harmonic declines. These can be then extrapolated into the future for generation of forecasts.
1D Model:
This is the classic Buckley Leverett tool for predicting breakthrough times and saturations in a water flooding scenario.
Multi Layer:
Relative Permeability averaging for different layers can be done using this tool, based on a variety of methods (like Stiles for instance). The resulting rel perms can then be used in MBAL or the Buckley Leverett tool for further analysis.
Tight Gas Type Curve Tool:
In cases where Material Balance is not applicable because of long transience periods, this tool can provide a good alternative for history matching and forecasting. It is based on well testing theory and incorporates a number of plots that can assist with history matching of these types of reservoirs.
