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Characterizing Oil & Gas Reservoirs Webcast Series

From SEM & EDS Maps to Numbers in Unconventional Reservoirs

Eric Goergen
Applications Scientist

 

FEI introduces a series of webcasts sharing the latest information on characterizing oil & gas reservoirs with electron microscopy technology.  In these video presentations, FEI application specialists will summarize their latest presentations from URTEC, SCA and SPWLA.

 

Webcast Summary

The fine grained nature of shale makes scanning electron microscopy (SEM) an essential part of the core analysis suite of techniques. Typically, the SEM is used for both imaging and for elemental analysis by energy dispersive X-Ray spectroscopy (EDS). Both imaging and EDS analysis require a specific approach when working on shale samples.

In many shale reservoirs, pores in the organic matter can be as small as 2nm, which would be the lower limit that can be visualized in the SEM. Imaging these small features comes at the cost of a very limited field-of-view. The high magnifications necessary to resolve the smallest pores translates to a very limited area that will be imaged. This raises serious questions about the representative nature of the SEM images. Creating SEM image mosaics by stitching as many high-resolution SEM images as needed to resolve both the fine details of the pores as well as a representative view of the overall rock microstructure overcomes the field-of-view resolution paradox.

EDS analysis itself also has some serious limitations for shale characterization. For a shale sample where grain sizes of clays, micas and organic particles are sub-micron, the EDS spectrum can contain multiple phases. The EDS analysis is hence complicated not only by the clay minerals themselves but also because the spectra may contain signals from multiple clay species.

The first results for which the EDS spectrum was analyzed in each pixel are presented. The mineral content and the relative proportions of phases are known in each pixel. These data permit insight for sub-micron mineral spatial associations not attainable by any other technique. This technique provides statistically meaningful data on what phases are interacting spatially, and further refines the analysis of mechanical properties of shale and other mudrocks from images only.

This webinar will cover:

  • Textural and mineralogical heterogeneity in shale
  • MAPS Technology for creating SEM mosaics
  • Workflow for Advanced Core analysis with the SEM technology

This webcast may be viewed online, on-demand, with registration.