Mineral Characterisation of Subsurface Sandstone Reservoir Clays

Oil RigReservoir Storage and Transmission of Valuable Resources

Sandstone reservoirs play a vital role in the storage and transmission of valuable resources, such as drinking water, crude oil, and natural gas. Porosity and permeability are two key properties that together affect whether sandstones can store and transmit commercially usable quantities of these fluids. Clay minerals are often the primary component of sandstones that impact porosity and permeability. Thus, the capability to determine the physical and chemical characteristics of clay minerals in sandstones, and then to understand the economic ramifications for developing aquifers or reservoirs, are of critical importance to the water and hydrocarbon industries.

Clay Minerals Pose a Difficult Customer Challenge

Many factors interact to influence the petro-physical properties of sandstones, but the types of clay minerals that fill pore spaces, together with their abundance and crystal size, are particularly significant. The very fine crystal size and complex mineralogy of clays combine to make them notoriously difficult to identify and to characterise using standard petrographic techniques, such as transmitted light microscopy. Without an in-depth understanding of clays and their properties, it can be hard to assess why a hydrocarbon or water well is producing poorly and, therefore, to determine what remedial actions might be taken.

Imaging and Analysing Clays with Electron Microscopy

The two scanning electron microscopes (SEM's) in the Imaging Spectroscopy and Analysis Centre (ISAAC) in the School of Geographical and Earth Sciences (GES)  are ideal for evaluating those aspects that limit the porosity and permeability of sandstones.

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