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Measurement of Pore Space Topology and Interfacial Areas inside Rock
Background:
Geometric information of pore space topology and interfacial areas
inside rock is the basis of upscaling theories that describe
macroscopic fluid properties using microscopic information. We are
developing an advanced optical video method (Optical Coherence Imaging,
OCI) that can "see" through translucent media, such as dilute drilling
muds and silica sandstone, and probe fractions of a millimeter into
sandstone rock to provide three-dimensional information on pore
topology (Figure 1). This optical imaging process can look 10 times
deeper through translucent media than "ordinary" optics used in
standard down-hole televiewers. Full-Frame images at video rates boost
imaging rates by several orders of magnitude over the traditional
confocal technology. Figure 1. Three-dimensional test object with 50 micron step heights is shown in the photograph on the left. The holographic reconstruction from OCI is shown on the right and enables the calculation of surface-to-volume ratios. Application to Rock: Holographic 3-D Laser Imaging into Sandstone P. Yu, M. Mustata, L. J. Pyrak-Nolte and D. D. Nolte, Geophysical Research Letters, vol 29, no. 20, p1988-1991, doi:10.1029/2002GL015108, 2002 Micro-Models from Photoprojection Lithography Background:
Studies of micro-models of porous media have yielded much insight into
fluid flow in a wide variety of systems. Synthetic and realistic
pore-space topologies are being developed with the use of
photolithographic fabrication methods. An important component of this
work is the fabrication and study of micromodels whose geometry is
based on our imaging results for real porous media from OCI and Wood's
Metal Injection Methods. The advantages of our techniques include
extremely high (sub-micron) spatial resolution, as well as high
dimensional control and reproducibility (Figure 2). Figure 2. Random percolative pattern made with the projection photolithography technique. The smallest features in the image (400 microns by 500 microns) are on the order of one micron. (Light gray regions represents the pore space and dark gray regions can be thought of as grains. Interfacial Area Measurements from Micro-Models: Linking Pressure and Saturation through Interfacial Areas in Porous Media J.-T. Cheng, L. J. Pyrak-Nolte, D. D. Nolte and N. J. Giordano, Geophysical Research Letters, vol. 31, L08502, doi:10.1029/2003GL019282, 2004 Support Page: Movies of Data Page last modified: 12/10/2007 03:41:35pm |
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