HR: 0800h
AN: H11B-0300    [Abstracts]
TI: Effects of Bedding Plane Orientations on Two-Phase Flow in Shear Fractures
AU: Mohammed, N
EM: nxm230@psu.edu
AF: The Pennsylvania State University, The Center for Quantitative Imaging, 204 Academic Activities Building, University Park, PA 16802 United States
AU: Al Enezi, S M
EM: sma219@psu.edu
AF: The Pennsylvania State University, The Center for Quantitative Imaging, 204 Academic Activities Building, University Park, PA 16802 United States
AU: Halleck, P M
EM: pmh2@psu.edu
AF: The Pennsylvania State University, The Center for Quantitative Imaging, 204 Academic Activities Building, University Park, PA 16802 United States
AU: Elsworth, D
EM: elsworth@psu.edu
AF: The Pennsylvania State University, The Center for Quantitative Imaging, 204 Academic Activities Building, University Park, PA 16802 United States
AU: * Grader, A S
EM: grader@pnge.psu.edu
AF: The Pennsylvania State University, The Center for Quantitative Imaging, 204 Academic Activities Building, University Park, PA 16802 United States
AB: Multi-phase transport in fractured rocks has a significant impact on hydrocarbon recovery processes in hydrology and petroleum engineering. This study examines the transport mechanisms in two types of cylindrical layered sandstones that were fractured in shear mode: a. samples were cut perpendicular to bedding and sheared perpendicular to bedding, and b. samples cut parallel to bedding and sheared parallel to bedding. The cylindrical samples (length=70mm, diameter=25mm) were fractured in shear mode under a constant strain rate and a fixed radial confining stress. The axial fracture displacements were about 0.5 mm. The samples were saturated with water, then, sequentially flooded with tagged water (miscible), oil (immiscible), and tagged water. The topology of the fractures and the distribution of fluids in the samples were determined by x-ray Computed Tomography (CT) at a voxel resolution of about 0.03 mm. The fracture perpendicular to bedding (case a) has few large porosity voids, exhibits a significant process zone, and has a high frequency of ridges driven by the bedding planes. The combination of the layers and the perpendicular fracture caused the displacements to sweep the entire volume of the sample. Only some of the few large fracture pores were not displaced by the last water injection stage. The fracture did not form a significant flow channel. About half of the oil was recovered during the last water injection stage. The fracture parallel to bedding (case b) has large porosity voids, has a small process zone, and has a low frequency of ridges. The presence of the parallel to bedding fracture created a flow channel in the sample, causing very low displacement sweep in the matrix. Some of the large pores in the fracture plane were not displaced during the first miscible injection stage. The immiscible injection stage invaded a portion of the fracture pores that were previously displaced by the tagged water. Finally, the last tagged water injection stage displaced most of the oil from the fracture. Only a portion of the large pores in the fracture form the flow channel, but some of the oil remains trapped in the largest pores of the channel. The relative orientation of the fracture plane with respect to the bedding planes has a significant impact on multi-phase fluid transport in fractured rocks. Fractures parallel to bedding tend to form large connected pores that channel fluid flow and reduce mass transport from the fracture to the matrix. Strong channel flow has not been observed when the fractures were perpendicular to bedding.
DE: 5104 Fracture and flow
DE: 5139 Transport properties
DE: 3947 Surfaces and interfaces
DE: 3954 X ray, neutron, and electron spectroscopy and diffraction
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting