- Number 341 |
- July 11, 2011
Seeing the Effects of Rock Heterogeneity on CO2 Movement
Dry sample scan of the CAS
sandstone core using (from left
to right in the image above)
NETL’s medical, industrial, and
All three DOE's National Energy Technology Laboratory X-ray CT scanners were recently used to characterize flow patterns during CO2 flooding of a sandstone sample from China. This work was part of a U.S.-China Energy Partnership that involves the Chinese Academy of Sciences (CAS), NETL, and PNNL. A delegation of scientists from the CAS brought a core sample from a sandstone formation in the Ordos Basin, China, that is of interest for potential CO2 storage. NETL’s medical CT scanner and industrial CT scanner were initially used to determine macro-variations in the sample structure, which included visually distinguishable bedding planes. Petrographic analysis of this core revealed that the lighter-colored bedding planes contained a high level of calcite. The figure above left shows the results from the medical CT scanner and industrial CT scanner in the two left-most images. Note the higher resolution that is capable with the new industrial CT scanner.
A small sub-core was analyzed with NETL’s micro-CT scanner to determine the pore scale features of these bedding planes. A region was scanned that contained both a calcite-rich bedding plane and a calcite-lean region next to it. This scan is shown in the right-most image in the figure above. The resolution of this image is 2 microns/pixel and shows that some of the calcite (lighter gray) is not bonded to the sand grains (darker gray) and that there is some porosity (black), even in the calcite-rich region.
Sequence of 3D reconstructions
CO2 within the core preferentially
filling the open bedding planes during
the flow experiment; flow is from
left to right.
[Linda Morton, 304.285.4543,