The Material Balance Program (MatBal) predicts the change in reservoir pressure with respect to cumulative production and the corresponding influence of any aquifer that may be in contact with the reservoir. MatBal is designed to analyze one reservoir at a time; however, the field model integrates as many reservoir models as necessary to describe field performance. The MatBal program lists all of the reservoirs used to describe the field model and any simulation or history match of a reservoir is initiated by simply selecting the target reservoir.


MatBal in the "Simulation Mode"

In the "Simulation Mode", sufficient reservoir and aquifer characteristics are entered to facilitate the material balance calculations. Then, a cumulative production forecast is entered and MatBal generates a forecast for reservoir pressure. This mode is useful for simple cases to develop an understanding of reservoir response to a particular production forecast, regardless of well deliverability.

More complex material balance simulations are run using DynaField that integrates well performance, network deliverability, well scheduling and multi-reservoir material balance analysis. In this context, a common use for the "Simulation Mode" of MatBal is to test reservoir description input data prior to launching a complex DynaField run; or, to isolate one reservoir and study the results of a DynaField run.


MatBal in the "History Match Mode"

In the "History Match Mode", a cumulative production history is entered along with the corresponding measured reservoir pressures. Rather than entering the data directly, an import feature is designed to load data from the Production Database (ProdDB). Historical production data for all the wells in the field are stored in the Production Database (ProdDB). The import feature searches the database for all production from the target reservoir, computes cumulative production, locates measured reservoir pressures and imports the data into MatBal. Then, one or more regression algorithms are utilized for adjusting reservoir and aquifer characteristics to best match the historical data. The regression analysis returns the best fit characterization coefficients for use in a MatBal "Simulation Mode" run or in a DynaField run.