Visualization Sciences Group (VSG) reports the successful combination of its Avizo 3D analysis software and Comsol’s Multiphysics simulator to investigate shale gas source rock porosity and permeability. The work was carried out for ExxonMobil and presented at the National Agency for Finite Element Methods and Standards (NAFEMS) World Congress held in Boston last May.
The team used data obtained from a focused ion beam scanning electron microscope (SEM) to produce a 3D ‘nanoscale’ model of the shale gas source rock. VSG’s Avizo software was used to characterize the sample’s pore space. The technique distinguishes three phases of the sample—rock, organic matter and void.
An image processing technique know as ‘image space segmentation’ was used to separate the three phases in the model space. Further processing distinguishes connected and unconnected pore space.
The high resolution map of the pore space is then input to Comsol’s full physics simulator. This was used to perform ‘virtual physics experiments’ a.k.a. flow simulations on the digitized model. The flow simulation results were used to determine the permeability of the sample.
VSG researcher Shuang Zhang observed ‘We can do things in the digital world a lot cheaper and faster than in the lab. The industry is only just becoming aware of this image-to-simulation workflow. An extraordinary amount of information can be obtained with these techniques, much more than we have ever seen before.’
We don’t know if this came as a direct result of the VSG/Comsol experiment, but ExxonMobil has spent $3 billion on shale gas leases since it shelled out some $35 billion for XTO Energy last year. More from www.oilit.com/links/1107_3 (VSG) and www.oilit.com/links/1107_4 (Comsol).
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