Who says science isn't fun? In their daily work, experienced microscopists
at JEOL USA Inc. in Peabody,
Massachusetts look at every kind of sample imaginable - paper, neurons in the
brain, ceramics, semiconductors, insects, and forensic evidence, to name just
a few - through the state-of-the-art scanning electron microscopes (SEMs) that
the company manufactures and sells. No matter how long they have been doing
this type of work, they are often amazed by the details and the interesting
things they observe magnified at hundreds of thousands of times.
This week, during a SEM training session for an existing energy-related customer,
JEOL specialists Dr. Natasha Erdman and Tony Laudate were examining the sample
of oil shale in the microscope when they came upon this startling image that
resembles a skeletal face and looked somewhat familiar to them. “It's
our version of ‘The Scream' by E. Munch, said Mr. Laudate. Naturally
they knew that what they were really looking at was an ion-beam polished cross
section of quartz (the skull), pyrite (the eyes, nose, and mouth) and kerogen
(the dark patches that are organic material). But the image was saved and will
definitely be one of the most unusual that JEOL has ever taken.
Studying Oil Shale's Potential with the Scanning Electron Microscope
The clear details shown in the picture (micrograph) from the SEM is due to
not only the optics of the microscope, but the way in which the sample was prepared
and precisely cross sectioned from a larger chunk of shale through the use of
a special ion-beam cross section polisher. This tool has become indispensable
for oil shale analysis.
One of today's hottest areas of potential under-utilized energy resources
is shale. Abundant in specific regions of the United States, oil shale is a
fine-grained, sedimentary rock composed of flakes of clay minerals and tiny
fragments of other minerals, especially quartz and calcite. Shale also has a
complex network of soft veins of an organic substance, kerogen and accessory
opaque minerals such as pyrite.
When heated, kerogen can release hydrocarbons, or fossil fuel. By studying
the internal composition of the shale and the network of kerogen filled veins,
scientists can determine the abundance and ease of extraction of oil.
Companies investigating this alternative source of energy have turned to JEOL
for not only the electron microscope, but a unique sample preparation tool that
creates pristine cross sections of oil shale. Without this tool, it is difficult
to prepare cross sections of shale without distorting and smearing the soft
veins of kerogen trapped in the composite.
The JEOL cross section polisher slices and polished the sliver of shale with
an argon beam to yield undistorted, precise cross sections. Every detail can
be clearly seen, allowing researchers to clearly see the network of veins of
kerogen in the sample, and can take the imaging a step further to make 3D reconstructions
of the pore network by using a Serial Slicing and Sampling technique with the
Multibeam focused ion beam (FIB) instrument. To see more images of shale and
other energy-related micrographs, visit www.jeolusa.com and click on the applications
tab.