Injection and production historical data are easily accessible and using them does not incur the costs of running field tests. The capacitance model (CM), an analytical model based on injection and production data, has recently been applied successfully in several field cases. The CM has two outcomes, rate prediction and well to well connectivity evaluation and primarily derived for waterflood period. This paper modified this model for primary production period.
The CM has been developed from linear productivity model and material balance equation and predicts the total production rate of each producer as a function of the injection rates of all injectors in the system and the bottomhole pressures (BHPs) of all producers. In this paper the CM is modified based on two methods, Pseudo Injectors and BHP methods. Pseudo Injectors method is used for well to well connectivity assessment and BHP method is used for production prediction.
The modified CM was applied for several synthetic field examples and one Iranian oil reservoir. The results of synthetic fields showed that the modified CM can assess the interwell connectivity, reservoir heterogeneity, strength of aquifer, and wellbore productivity in primary production period. In addition, the modified CM can predict production rate and determine suitable areas of future IOR application. The results of modified CM on Iranian field assessed the effect of aquifer in the area and evaluated the degree of heterogeneity of the sands around the producers.
Unlike simulation-based methods, the CM does not require geological and geophysical data to generate the initial model. Developed modified CM can be applied before IOR implementation to assess reservoir continuity and manage future IOR strategies such as well pattern and amount of injected fluid.