... oil sand complex reservoir minimum principal stress bitumen Upstream Oil & Gas wellbore storage breakdown pressure kPa Drillstem Testing pressure data Workshop Injection Rate principal stress interpretation fracture micro-frac test stress measurement hydraulic fracturing...

... homogeneous stress distribution can be produced in the specimen with the conventional triaxial test(confining pressure test). However, the intermediate principal stress is fixed equal to the minimum principal stress(compression test under confining pressure), in fewer cases, to the maximum principal stress...

... from breakdown and refracture tests in a borehole. Generally 2 to 3 holes in the same area are tested, and the results combined to give a mean minimum principal stress for the area. The method does not permit inspection of the borehole after fracturing to determine the orientation of the fracture...