Fluid Flow within Fractured Porous Media
Dustin Crandall,1,2 Goodarz Ahmadi,1 Duane Smith2,3 and Grant Brohmal2
1Clarkson University, Mechanical and Aeronautical Engineering Department, Potsdam, NY 13699
2Department of Energy National Energy Technology Laboratory, Morgantown WV 26505
3West Virginia University, Physics Department, Morgantown WV 26505
Fractures provide preferential flow paths to subterranean fluid flows. In reservoir scale modeling of geologic flows fractures must be approximated by fairly simple formulations. Often this is accomplished by assuming fractures are parallel plates subjected to an applied pressure gradient. This is known as the cubic law. An induced fracture in Berea sandstone has been digitized to perform numerical flow simulations. A commercially available computational fluid dynamics software package has been used to solve the flow through this model.
Single phase flows have been compared to experimental works in the literature to evaluate the accuracy with which this model can be applied. Common methods of fracture geometry classification are also calculated and compared to experimentally obtained values. Flow through regions of the fracture where the upper and lower fracture walls meet (zero aperture) are shown to induce a strong channeling effect on the flow.
This model is expanded to include a domain of surrounding porous media through which the flow can travel. The inclusion of a realistic permeability in this media shows that the regions of small and zero apertures contribute to the greatest pressure losses over the fracture length and flow through the porous media is most prevalent in these regions. The flow through the fracture is shown to be the largest contributor to the net flow through the media. From this work, a novel flow relationship is proposed for flow through fractured media.
AAPG Search and Discovery Article #90059©2006 AAPG Eastern Section Meeting, Buffalo, New York