Hounsfield Facility: 3D X-ray imaging
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Micro Computed Tomography (MicroCT) for Geosciences 

What is MicroCT?

MicroCT is a technology which allows you to see inside an object in 3D without cutting it open.  Materials with different densities can be separated, false coloured and numerically measured.  Through using the latest equipment, we are able to acquire images at resolutions from 150µm down to <1µm.  

Examples of MicroCT in Geosciences

Case Study 1: - Jurassic Oxford clay

Jurassic Oxford clay

Investigating the suitability of rocks for oil extraction.  The image on the left is a virtual cross-section through a 3D CT data set of a Jurassic Oxford mud clay.  The vertical fracture in the core contains (1) pyrite, (2) bitumen and (3) secondary mineralisation. 

CT can be used to study:

  • Location of bitumen
  • Fracture orientation
  • Interlocking of fractures
  • Fracture opening/closing
  • Phase identification
 

 

 

Case Study 2: - Holocene sediment

The video on the left is a  Holocene sediment with methane-derived authigenic carbonate (from the Irish sea).  This 3D rendering shows how CT can be used to explore porosity.  The main pores are separated from the main pore network (green) and have been numerically quantified. 

CT can be used to help answer questions such as:

  • Where does the hydrate come from?
  • When is it released?
  • How does it get stored?
  • How much methane is generated?
 

 

   

Case Study 3: - Lower Cambrian calcareous sandstone

Lower Cambrian Sandstone

Studying lower Cambrian sandstones from the Welsh borders in order to determine possible historic sea temperatures. 

On this virtual cross-section through a 3D CT data set features we can identify features such as: (1) calcareous, (2) phosphate replaced shell fossils, (3) surface crust and (4) shell fragments and glaunites.

 

 

 

 

 

Case Study 4: - Ordovician mudstone

Investigating the interplay between organic material and early mineral formation. The 3D rendering of CT data identifies graptolite fossils.  Some of the fossils (yellow) have a halo effect (blue) which affect the fracability of the rock.
 

 

 

Case Study 5: - Carboniferous interbedded silt-laminated mudstone

Carboniferous interbedded silt-laminated mudstone

A Carboniferous interbedded silt-laminated mudstone and mud-laminated sandstone. This is part of a potentially prospective shale gas interval, and includes abundant polished (i.e. slickensided) discontinuities.

On the virtual cross-section through the CT data set, we can identify features such as; (1) pyrite, (2) organic dispersions, (3) silt laminate, (4) mud laminates and (5) cracks could be identified.

 
 

How can the technology help you?


MicroCT has a number of advantages over other methods of microstructural analysis:
  • Microscopy requires the rock core to be mechanically sectioned.  Even the most careful preparation can have destructive effects.  In contrast, X-ray tomography can visualise the internal structure in 3D without any cross-sectioning or preparation. Reliable 2D and 3D information can then be derived from the data.  
  • Microscopy is restricted to analysing small sections of the overall product, making complex features difficult to visualise.  With X-ray tomography, the entire core can be imaged and analysed, in 3D, offering a data rich alternative.
  • Materials of different densities can be separated e.g. pores, aggregates and fossils.
  • Materials can be explored visually and quantitatively in 3D, studying characteristics such as:
      • 3D crack orientation and distribution.
      • 3D pore characterisation e.g. distribution/density, size and shape.
      • 3D grain analysis - discriminate and quantify true mineral phase distributions.
      • Temporal analysis e.g. monitoring structural dynamic processes, fracture analysis under geological stresses etc.
    • 3D images can be directly transformed into 3D meshes for fluid flow analysis or other numerical calculations.

 

Can we help you?

Using our interdisciplinary team of experts we are able to take care of the whole MicroCT data acquisition and data analysis process for you. We will take time to understand your research questions and discuss how we might be able to answer them. Through designing a customised data acquisition and image analysis package for your problem, you will obtain the best solution that X-ray micro-tomography can offer.

For more information or to discuss a new project contact Craig Sturrock:

e:   craig.sturrock@nottingham.ac.uk
t:   0115 951654

Hounsfield Facility

The University of Nottingham
Sutton Bonington
Loughborough, LE12 5RD

telephone: +44 (0) 1159 516786
email: craig.sturrock@nottingham.ac.uk