The influence of displacements arising from shear motion on two-phase flow through 3D-printed fractures

Fractures can constitute a large portion of the pore volume in a hydrocarbon reservoir and, consequently, undertake substantial deformation during production activities. However, numerous experimental studies on immiscible two-phase flow through fractures have relegated deformation. While the impact of surface roughness and aperture changes has been addressed, data are absent concerning the effect of shear deformation in these types of studies. Therefore, this investigation examines this subject utilizing 3D printing to visualize experiments, control fracture roughness, and incorporate shear displacements. Drainage experiments where water displaces silicone oil at a constant injection rate are conducted on synthetic fractures of a smooth and a rough surface type. These experiments involve increasing shear displacements perpendicular to flow and increasing mean fracture aperture values. Surface roughness is measured using the fractal dimension obtained from the variogram method. Fluid saturations are estimated through image processing, and the displacement patterns are analyzed through the fractal-based box-counting method. The image analysis of the two-phase flow displacements at water breakthrough indicates that surface roughness and displacements arising from shear motion could lead to a flow regime where capillary effects are more prevalent. Surface roughness is observed to affect the efficiency of the oil swept. Smooth fracture samples facilitate oil recovery before water breakthrough, but afterward, water channeling predominates over oil sweeping. Additionally, oil recovery exhibits a concave behavior with respect to shear displacements, with an increase in oil recovery from zero to mid-shear displacements, followed by a decrease in oil recovery at higher shear displacements. On the other hand, pressure measurements from two-phase flow displacements exhibit features that suggest the degree of surface roughness and the displacements resulting from shear motion alter their response. This research demonstrates the potential of 3D printing in the study of fluids flow through fractures and represents pioneering results on the effects of shear deformation in fractures on two-phase flow.