A fast simulator for hydrocarbon reservoirs during gas injection

A fast simulator is presented to forecast quickly the performance of oil reservoirs during gas (miscible and immiscible) injection based on transfer functions (TF). In this method, it is assumed a reservoir consists of a combination of TFs. The order and arrangement of TFs are chosen based on the physical conditions of the reservoir that are ascertained by examining several cases. The selected arrangement and orders can be extended. The only required data of this method is production and injection history that are easily accessible. Injection and production rates act as input and output signals to these TFs, respectively. By analyzing input and output signals, matching parameters are calculated for each case study. The outcomes of the method are compared with those obtained by a grid-based simulator. The comparison indicates a good agreement.