A hydraulic fracturing system for three dimensional stress determination has been developed. The calculation procedure of the system introduces new interpretation based on the facts obtained through laboratory hydraulic fracturing tests of intact rocks. Hydraulic fracturing data incorporated in the system include at least both the fluid pressures at steady flows in two longitudinalfractures produced around the boreholes of different orientationand the shut-in pressure in a transverse fracture which is apt to develop along a natural joint. Stress states in impermeable rock can then be evaluated by the system with neither assuming thedirection of principal stresses nor seismic measurements.
In this paper, the principles of the new method for three dimensional stress determination and the measuring system are described first, and then the results of in-situ measurements at several sites where the new system was applied for stress determination are reported.
