THEORETICAL AND EXPERIMENTAL INVESTIGATION ON SINGLE FRACTURE METHOD OF IN SITU STRESS MEASUREMENT

Abstract

Hydraulic fracturing stress measurements cannot provide the magnitude of maximum compressive stress with sufficient reliability. To overcome the defect, a new loading probe that can generate a fracture plane in any desirable direction, was developed. The authors examined a borehole wall stress condition induced by the probe and simulated a pressure-displacement curve using a boundary element method. The laboratory experiments provided apparent acceptable results, however, this investigation elucidated that the results come from the fact that ignoring twice large stress concentration at a crack position was canceled out by misreading a re-opening pressure twice large. Thus, it was found that establishment of a method to determine a correct re-opening pressure is essential to make this