TITLE:
Swelling Measurements of a Low Rank Coal in Supercritical CO2
AUTHORS:
Ferian Anggara, Kyuro Sasaki, Yuichi Sugai
KEYWORDS:
Coal Swelling Experiments; Visualization Method; CO2-Enhanced Coal Bed Methane Recovery; Low Rank Coal
JOURNAL NAME:
International Journal of Geosciences,
Vol.4 No.5,
July
17,
2013
ABSTRACT: Coal swelling in the presence of water as well as CO2 is a well-known phenomenon, and these may affect the permeability of coal.
Quantifying swelling effects is becoming an important issue to verify the suitability
of particular coal seams for CO2-enhanced coal bed methane recovery
projects. In this report, coal swelling experiments using a visualization
method in the CO2 supercritical conditions were conducted on crushed
coal samples. The measurement apparatus was designed specifically for the
present swelling experiment using a visualization method. Crushed coal samples
were used instead of block coal samples to shorten equilibrium time and to
solve the problem of limited availability of core coal samples. Dry and wet
coal samples were used in the experiments because there is relatively limited
information about how the swelling of coal by CO2 is affected by
water saturation. Moreover, some coal seams are saturated with water in initial
reservoir conditions. The maximum volumetric swelling was around 3% at 10 MPa
for dry samples and almost half that at the same pressure for wet samples. The
wet samples showed lower volumetric swelling than dry ones because the wet coal
samples were already swollen by water. Experimental results obtained for
swelling were comparable with other reports. Our visualization method using
crushed samples has advantages in terms of sample preparation and experimental
execution compared with the other methods used to measure coal swelling using
block samples.