A novel method for prediction of parameters of naturally fractured condensate reservoirs using pressure response analysis

摘要

Producing from gas condensate reservoirs under dew-point pressure and at constant temperature shows a complex behavior because of existing liquid condensate around the well. Zones with different mobilities generate three zones as a zone away from the well containing only gas, a zone having liquid around the well and finally a zone containing movable oil and gas. Existence of condensate around wellbore reduces gas relative permeability and as a result productivity index of the well will decrease. In fact, this condensate acts like an additional skin and investigating of this behavior can be difficult because of the complex fluid flow processes. Well test analysis in naturally fractured reservoirs is generally based on radial flow. In this study, first, a naturally fractured condensate reservoir in a compositional simulator is created and then, using drawdown test, pressure data versus time is generated. By proposing a new method, the data is analyzed and static and dynamic reservoir parameters are obtained. Resulted values of these parameters are compared with real values, which were defined in the model. It is shown the proposed method estimates parameters and characteristics of reservoir much better than conventional dry gas techniques.