Computed tomography (CT) with X-ray scan is a radiological
imaging technique that was developed for medical radiology by Hounsfield in
1972. It took several generations of development until becoming more satisfactory
for petroleum research applications. Most recently, more advancements were
presented that can allow better tomographic imaging with X-ray CT scan and
thus, opens the door for a wider range of application of this technique. This
work aims at giving a brief overview of the basic principles of X-ray CT scan
in petroleum engineering research and providing state-of-the-art examples of
X-ray CT scan is a noninvasive, non-destructive, rapid, easy
to apply, quantitative imaging technique that can offer excellent spatial
three-dimensional (3D) resolution. It gains a wide applicability because of its
adaptability to many types of experimental setup and procedures and image
processing options. A quick search on
the SPE electronic library – onepetro – by using “CT scan” has returned 2,139 results.
Additionally, it has returned around 899 results by using the words “computed
tomography.” Microscopic computed tomography (micro-CT) scan technique, as a
new technology, has also shown great addition through the higher-resolution visualization
of pore structure and fluid displacement.
Different rock and rock-fluid properties had been provided by
the X-ray CT scanners. Petrophysics and reservoir engineering were mainly the
most important fields of CT scan applications. Rock density, porosity,
permeability, and fluid saturations can be determined with higher rate of
accuracy. Different studies of rock mechanics, fracture identifications, filter
cake and drilling fluid invasion characterization, mineralogical quantification,
and fluid displacement measurements in enhanced oil recovery (EOR) applications
had been conducted based on CT scan analysis. It can supplies enough data to
obtain 3D micro structure of the studied rocks.
The objective of this paper is to give an
updated overview of the state-of-the-art applications of X-ray CT scan in the
oil and gas research, which might provide better understanding of the use and
analysis methods of such powerful tool of characterization.