Date of Graduation
Statler College of Engineering and Mineral Resources
Industrial and Managements Systems Engineering
Fernando V Lima
Three samples of Marcellus and Eau Claire shales were sheared in a modified Hassler style core holder. Before testing and after each shear step, the hydraulic transmissivity was measured and a high-resolution 3-D image taken using a computer tomography (CT) scanner, resolution ranged from 26.7 to 27.6 microns. Each sample was sheared four to eight times during a test providing a total of 37 fracture geometries. The 3-D binary images of each fracture were processed based on a voxel connectivity graph, removing any clusters that were not connected to the main fracture. Two-dimensional aperture maps were then generated by flattening the 3-D image along the Y-axis creating a mesh to perform modified local cubic law simulations (MLCL) on. Experimental data were compared against MLCL simulations run on aperture maps produced before and after cluster processing to assess the effectiveness of this technique. Additionally, the discrepancy between experimental data and simulation results was investigated relative to several geometric parameters known to affect the accuracy of this MLCL formulation relative to a full Navier-Stokes simulation.;Cluster processing improved the agreement between experimental and simulated transmissivity and reduced the roughening effects of disconnected void space has when incorporated into the aperture map. The simulation error had no discernible relationship to the geometric parameters tested, indicating that the primary source of error is not the simplified physics of the MLCL model. This corroborates with results presented in a related study by Mofakham, et al. (2017). The cluster processed geometries were then used to compare the shearing responses of the Marcellus and Eau Claire shale families. Both sample sets are shown to have a very similar response to shearing when evaluated against multiple geometric and statistical quantities. Knowing that these distinctly different shales behave in a parallel fashion is an important step in understanding how sensitive shearing is to lithology composition and how applicable research performed in one region is to another.
Stadelman, Matthew A., "Comparing the Hydrodynamic Response of Fracture Shearing in Marcellus and Eau Claire Shales" (2017). Graduate Theses, Dissertations, and Problem Reports. 6712.