In this work we present a new approach to include the influence of hydraulically induced fractures on the performance of a reservoir. Hydraulic fracturing has become a state-or-the-art completion for all kinds of wells and reservoirs. Especially in the case of low permeable tight gas reservoirs, fracturing is essential for efficient reservoir exploitation. As a result of this, most gas wells are nowadays hydraulically stimulated. However, in the case of low permeable tight gas reservoirs with rather long fractures an appropriate simulation requires a highly-flexible time-dependent adaptive gridding of the model in the vicinity of the created fracture.
Our work is based on a recently proposed simulation method which combines a dual continuum approach with a time-dependent highly flexible gridding method in order to accurately simulate the influence of hydraulic fracturing on well and reservoir performance. We extend this method by treating the process of hydraulic fracturing as a part of the simulation. At any given time during the simulation a hydraulic fracture can be initiated for any desired well. The geometry of the fracture is inferred from a given state of stress, injection rate, and elastic rock properties using the Perkins-Kern-Nordgren model. Once the fracture is created the simulation grid is appropriately adopted.
We have implemented our approach in a commercial reservoir simulator which provides the necessary gridding flexibility and a dual continuum formulation that allows for the definition of locally restricted dual porosity or dual permeability cells. We will show how the accuracy and flexibility of our method enhances the ability to simulate the performance of a reservoir fracture treatment.