Fracture flow and fracture cross flow experiments

Flow through single fractures depends strongly on the fracture aperture and the flow channels formed by the fracture surface contact areas. Since fracture apertures are highly stress dependent, production induced stress variations will change fracture apertures and in addition cause blockage of the flow channels by deformation products during shearing. This gouge formation may, together with changes of the pore structure in the fracture walls, also have an influence on the fracture cross flow. The laboratory results presented in this paper indicate that favourably oriented fractures can dramatically increase the total flow, even in rather permeable sandstones. However, the same fractures if oriented nearly perpen-dicular to the flow direction, can reduce fracture cross flow substantially. The effects of fracture normal stress, shear displacement, intact rock strength and permeability and fracture surface properties on fracture flow and cross flow are demonstrated by the results presented.