Failure characterization in geomechanical testing using nuclear magnetic resonance spectroscopy

In this work we present results from nuclear magnetic resonance (NMR) spectroscopy characterization applied to both dilatant and compactive failures generated by triaxial geomechanical testing on outcrop chalk saturated with two distinct brines: CaCl₂ based and CaCO₃ equilibrated water. We identified open fractures, pore collapse and micro-fractures from the NMR results. Plugs saturated with CaCl₂ brine behaved more ductile than the CaCO₃ saturated ones. NMR allowed a better insight on the degree of plastic deformation in triaxial tests than interpretation of stress/strain curves.