Abstract: Core disking is one of indicators of elevated geostress magnitude. The shape of disked cores is directly subjected to values and directions of three principal stresses. In the case of drilling-induced core disking, 3D geostress states cannot be measured by usual overcoring methods. Based on the previous studies of core disking, we provide a convenient substituted measurement of 3D geostresses by determining the geometry of disked core’s surface. Practically, the directions of three principal stresses from our method are quite close to those from other measurement in the vicinal site. The differences of inclination are in the range of 10°; and those of azimuth less than 20°. Moreover, the magnitudes of principal stresses satisfy the well-known condition to cause core disking.

Key words: high geostress, core disking, overcoring methods, height distribution at the periphery of disked core, critical tensile stress coefficients