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, Australian Centre for Geomechanics, Perth, pp. 615-624.
The interaction between water-based drilling fluids and shale formations comprises a complex coupled process that can both lead to wellbore instability and that can be leveraged to improve wellbore stability. Achieving the desired result depends on rapid characterisation of the parameters that govern the fluid/rock interaction, along with a chemoporomechanical approach to the analysis of wellbore stability. Here we present a chemoporoelastic solution for a plane strain wellbore that is subsequently used to predict the onset of shear and tensile failure of the wellbore. Wellbore stability is thus shown to depend on the so-called chemomechanical coupling coefficient characterising the shale. A new approach for rapid characterisation of this parameter from experiments using sub-centimetre specimens, which can be obtained from the drill cuttings, is demonstrated.
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