f Determination of Foliation in Basement Rocks Using Borehole Image Log Data and Its Influence on the Fracture System

A factor that can have an influence on the natural fracture system is foliation. Until recently this feature was rather under estimated within the industry. Foliation does not occur as individual feature such as fractures but rather affects the entire host rock, usually as a preferred shape and/or crystallographic orientation of mineral grains and/or aggregates of mineral grains (Milnes et al., 2006).