From Core to Pore: Multi-scale, Multi-dimensional Characterization of Fine-grained Reservoir Rocks
Mineralogy and microstructure are key variables defining the physical properties of a rock. Rocks that have a heterogeneous mineralogy/microstructure will exhibit equally heterogeneous physical properties. Shale typically displays significant mineralogical and microstructural variation. Quantifying shale mineralogy and microstructure permits more accurate determination of a variety of physical properties important to modeling production potential: e.g. organic versus inorganic porosity, permeability, brittleness etc.
The microstructural elements that define properties of interest for a typical shale exist over 9 orders of magnitude in length-scale (nanometer to meter). Therefore, a main challenge exists in upscaling mineralogical and microstructural observations in a way that provides characterization of nanometer-scale observations that are representative of the rock at centimeter to meter-scales.
Three recent technological advances have paved the way for routine, accurate microstructural characterization from the nanometer to meter scales: Ultrahigh resolution scanning electron imaging, automated mineralogy and 3D imaging (X-ray computed tomography (CT) and FIB/SEM analysis). When combined, data from these sources can be used to quantify shale at a resolution that is only now possible.
We present examples of integrating multi-scale 2D and 3D electron imaging with proven automated mineralogy algorithms to more accurately evaluate the mineralogy/microstructure of shale and other fine-grained reservoir rocks. This multi-scale multi-dimensional workflow also provides a pathway for upscaling observations in a repeatable and quantifiable way. Integration of mineralogical and microstructural data provides a unique opportunity to evaluate shale and other fine-grained reservoir systems with unparalleled fidelity.
AAPG Search and Discovery Article #90207 © AAPG Geoscience Technology Workshop, Unconventionals Update, November 4-5, 2014, Austin, Texas