Physical Modelling
Greenhouse Gas (CO2) Sensing
New knowledge is being obtained into how greenhouse gases in
general, and mixed quantities of CO2 and methane in particular,
dissolve in water. Methods for remotely distinguishing water
from carbon dioxide have been published. Such knowledge allows
the ability to monitor and quantify the amount of CO2 injected
during sequestration processes, and will allow the future
dependable management of CO2 injection operations through
controlled verification of the CO2 storage process.
Supercritical CO2 research is being conducted in a large
pressure chamber into which CO2 is injected and monitored using
both 3D and seismic tomography methods. In addition, research
into using the 3D seismic method for monitoring the injection
process at Australia’s first injection test site is ongoing.
Collaborative work is being done with the Cooperative Research
Centre for Greenhouse Gas Technologies (CO2CRC) researchers at
University of Adelaide and Melbourne, as well as researchers in
Delft University (Holland) and Montana (US).
Research Contact: Prof Brian Evans (B.Evans@curtin.edu.au).
Physical Modelling of Reservoirs
Fluid flow through reservoir fractures and
heterogeneities often cause reservoir simulators to fail to
adequately predict oil and gas production. In addition, it is
often very difficult to develop new algorithms without knowledge
of the reservoir characteristics in the first place. The Curtin
Physical Modelling laboratory builds models of geological
structure and records ultrasonic data over the models to provide
simulated field data for use with standard or new algorithms. In
addition, the laboratory has a pressure chamber in which models
may be pressured to simulate conditions underground. With
visiting researchers from Montana University (US), techniques
are developing to allow 3D and cross-well tomographic recording
of models.
Research Leader: Prof Brian Evans (B.Evans@curtin.edu.au).
Reservoir Imaging
Technologies have been developed over the
years to understand how fluid flows through reservoirs during
production. However, where karst or near-surface basalt
conditions occur, it becomes impossible to image the reservoirs
due to excessive seismic scattering. A new method has been
developed and patented, in which a low cost horizontal well is
drilled beneath the overburden, to allow the insertion of a
seismic cable and consequent recording of seismic data, to
produce an image of the reservoir for the first time. An initial
experiment will be performed over methane coal fields in
Queensland in an attempt to demonstrate this as a feasible
solution to imaging reservoirs beneath complex karst and basalt
topography.
Research Leader: Prof Brian Evans (B.Evans@curtin.edu.au).
Reversed Time Acoustics and Virtual Source Imaging
A low cost low power continuous vibratory
system has been developed for seismic imaging applications over
reservoirs. In addition, methods of time reversed acoustics have
been successfully applied to imaging targets beneath strongly
scattering near-surface layering. These methods are soon to be
applied in field tests to assist the monitoring of injected CO2
and methane production. The use of continuous sources holds
promise of considerably improving the precision of seismic
measurements. Changes in travel time of less than a micro-second
can be achieved and will lead to measurements of frequency
dependent velocity measurements of fluids in porous media.
Changes in the velocity dependent dispersion will lead to the
characterisation of fluids and of reservoir conditions as fluids
are injected or withdrawn from reservoirs.
Some work on time reversed acoustics was done in collaboration
with the Laboratoire Ondes et Acoustique in Paris. This has
developed now to laboratory and numerical simulation of the
application of time reversed acoustics in simulating sources
below surface multi-scattering layers in a method known in
geophysics as the Virtual Source Method.
Research Leader: Associate Prof Bruce Hartley (B.Hartley@curtin.edu.au).
Tomography in Heterogeneous Media
One of the main problems with imaging in heterogeneous media
is the fact that the rays are generally curved. Imaging methods
based on generalised Radon transform that takes into account the
curved rays are being developed.
Research Leader: Dr Andrej Bona (A.Bona@curtin.edu.au).