Chemo‐Mechanical Coupling in Fractured Shale With Water and Hydrocarbon Flow
Quinn Wenning, Claudio Madonna, Takeshi Kurotori, Claudio Petrini, Junyoung Hwang, Alba Zappone, Stefan Wiemer, Domenico Giardini, Ronny Pini
Abstract
Abstract The transport of chemically reactive fluids through fractured clay‐rich rocks is fundamental to many subsurface engineering technologies. Here, we present results of direct‐shear laboratory experiments with simultaneous imaging by X‐ray Computed Tomography in Opalinus claystone with subsequent fluid injection to unravel the interplay between mechanical fracture deformation, fluid sorption, and flow. Under constant radial stress ( σ c = 1.5 MPa), the average mechanical aperture increases with shear displacement. Upon brine injection, is reduced by 40% relative to initial conditions ( μ m) and fluid‐sorption induces a divergent displacement of the two sample halves (Δ h = ±50 − 170 μ m) quantified by digital image correlation. None of these changes are observed in a control experiment with decane, indicating that creep is subordinate to swelling in sealing the fracture. Swelling‐induced changes in permeability within the fracture are heterogeneous and largely affect the fracture flow field, as computed using numerical simulations.