The orientation and magnitude of the in-situ stress field and its spatial variation in the Oberpfalz deep boreholes are investigated by a set of complementary methods based on borehole geometry and borehole seismic methods. Orientation and shape of stress-induced wellbore breakouts are controlled by the ambient stress state and rock strength. The orientation of the crustal stresses throughout the deep boreholes will be determined by interactive digital analysis of the naturally-occurring breakouts and applying a recently developed stress measurement method that utilizes information on the size and shape of wellbore breakouts, rock strength and the magnitude of the least principal compressive stress (as determined from hydraulic fracturing measurements) to determine the magnitude of the maximum horizontal principal stress.
