| ABSTRACT:
Barry
Freifeld, Timothy Kneafsey, Jacob Pruess, Paul Reiter, and
Liviu Tomutsa have developed a compact and portable X-ray
scanning system that allows real-time examination of core
sample structure at remote drilling locations. The Berkeley
Lab computed tomography imager is capable of multi-energy
scanning to identify various materials comprising a sample.
Three-dimensional
scans can be taken at a rate of three minutes per foot of
core length. With whole-round core samples, resolutions between
50 to 200 microns can be achieved.
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A 3-D reconstructed image of a core slice containing methane
hydrate (left) and ice (right) in a sand matrix. |
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Conventional
X-ray tomographic imaging systems fully enclose the imaging
equipment in a lead-lined room that shields the operator from
harmful radiation. These systems weigh 1000 kgs or more and
are difficult to transport. The dimensions of the Berkeley
Lab scanner are 1.37m x .61m x 2.03m and the entire system
weighs less than 300 kgs, due largely to the highly efficient
design of the X-ray shielding. This difference in weight means
that the Berkeley Lab apparatus can be easily located at the
drilling site. The Berkeley Lab system also meets U.S. Food
and Drug Administration specifications for cabinet safe equipment,
including the requirement to provide safety interlocks that
prohibit operation when the shielding shell is open.
The
Berkeley Lab X-ray scanner is well-suited for obtaining real-time
images to determine the presence and spatial distribution
of methane hydrate, a potential energy source. Because methane
hydrate rapidly decomposes at ambienttemperature and pressure,
core samples containing the hydrate currently have to be maintained
at high pressures or low temperatures and transported for
imaging, or heavy and cumbersome imaging systems must be transported
to the field site so that samples can be imaged immediately
after extraction. The portable X-ray imager eliminates these
problems because it can easily be transported to the drilling
location and can rapidly scan core samples. The Berkeley Lab
scanner is also useful for real-time laboratory monitoring
of core floods.
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