ABSTRACT
Seawater injected into a hydrocarbon bearing reservoir is known to affect the strength and deformation properties, leading to an increase in oil production, but in some cases also to subsidence, compaction or borehole instability. Considering the fractured nature of the reservoirs, it is of major importance to understand the displacement process in conjunction with the fractures. In this study, waterflooding has been carried out at stress states close to shear failure. Local resistance measurements have been used to track the waterfront through the specimen, to indicate fracture flow and to estimate saturation changes. Local strain measurements and resistance data illustrate the displacement process, and whether matrix or fracture plane deformation dominates during waterflooding. The results show that waterflooding does not seem to affect the shear failure condition of the chalk significantly, but it affects the magnitude and nature of the deformations observed in the shear failure phase.
