Influence of mechanical damage on fluid flow patterns investigated using CT scanning imaging and acoustic emissions techniques

[1] In order to get some insight into the influence of mechanical deformation on fluid flow patterns, we performed series of X-ray CT scanning runs during capillary imbibition experiments to image the water front displacement in Bentheim sandstone samples. A three steps procedure was followed: 1) intact rock samples were tested, 2) the samples were deformed in creep experiments under triaxial conditions with recording of acoustic emissions, 3) the deformed samples experienced a second capillary imbibition test with CT scanning imaging. Using image analysis tools, relevant flow parameters like the height, velocity and curvature of the water front were measured. Stress-induced damage had a significant impact on the flow patterns. However contrasted results were obtained: localized damage evidenced by acoustic emissions clustering resulted in one experiment in local disturbance of the flow patterns, whereas in the second one a fracture detected by CT scan did not modify the local flow geometry.