Abstract
Hydraulic fracturing is carried out to create a conductive fracture in tight reservoirs to provide an easier path for fluids to flow to the wellbore. The actual performance of fractured wells is often turned down due to the loss of fracture conductivity. The inertial effects such as Forchheimer drag and acceleration are believed to the major sources for this. This paper presents an analytical method to model the accelerating flow effect on the production performance of hydraulically fractured wells by modifying the fracture conductivity. The method is suitable to conveniently incorporate the accelerating flow effect in a production prediction model usually used for fracture treatment design and optimization. The method is then used to demonstrate that the accelerating effect is the only one source for the minimum of fracture conductivity, one of the major sources for the loss of fracture conductivity, and account for the source for discrepancy between the predicted and actual productivities.
1. INTRODUCTION
Hydraulic fracturing is carried out to create a conductive fracture in tight reservoirs to provide an easier path for fluids to flow to the wellbore. The flow rate that can be achieved by hydraulic fracturing has a strong relationship of fracture treatment is usually optimized to be productive as well as cost-effective. A flow rate prediction model is usually used in the design process. The promising aspect of such an integrated fracture design optimization approach is demonstrated by Rahman et al [1]. However, the actual performance of fractured wells is often turned down due to the loss of fracture conductivity. The non-Darcy flow effect is believed to be one of the major sources for this. The general mathematical form of the Darcy’s law that is used for fluid flow modeling through a porous medium can be expressed as follows:
