IN-SITU STRESS DIRECTIONS FROM BOREHOLE FRACTURE TRACES

Aadnoy, B.S., 1990. In-situ stress directions from borehole fracture traces. J. Pet. Sci. Eng., 4: 143-153. Logging tools are recently introduced which determine fracture traces on the borehole wall.* These are valuable tools in geological reservoir analysis. Information about induced fracture traces from borehole fracturing can be used to estimate the directions of the in-situ stresses. This paper derives a model for that purpose. A few cases which can illustrate certain applications are also included. It is of particular interest to determine whether the induced fracture extends axially at an angle relative to the borehole axis. The main result of the model is to determine whether the principal in-situ stresses are oriented in a vertical plane, an horizontal plane, or at intermediate directions, as often expected in deeper geological structures.