Coupling In Situ X-Ray Micro-Imaging And Indentation: A Novel Approach To Evaluate Micromechanics Applied To Oil Shale

Abstract:

A novel approach for shale micro-mechanics characterization has been developed, coupling micro-indentation measurements with in situ synchrotron X-ray imaging. The present work shows for the first time such a measurement at non-ambient conditions in a Green River shale sample. The shale sample is placed in a mini-triaxial cell developed for X-ray imaging with equipped a system to perform a Brinell-type indentation by controlling the top piston force. The setup allows to control different conditions (P/T/Fluid) of the sample, and in the present case we show the results for the shale in water. The full compliance curve was recorded, along with 3D datasets of the sample microstructure at different loading/unloading stages. A digital volume correlation analysis has been carried out to obtain local strain fields. This analysis has been complemented with the analysis of the cracks. Finite element modeling has been used to replicate and generalized the observed behavior in the shale. This study validated this experimental approach, providing a breakthrough in understanding micro-mechanics in shales, and demonstrates how this class of experiments can be important for studies involving the prediction of the evolution of propped fractures in reservoir shales, providing fundamental information about the embedding mechanisms of proppant on the fracture surfaces.
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