Improved routine estimation of the minimum horizontal stress component from extended leak-off tests

In this paper, several high-quality extended leak-off tests (XLOT) with flowback are reviewed. It is argued that a properly performed XLOT with flowback gives a precise determination of the minor in situ stress. Further, it is found that the improved stress estimate tends to predict a stress level significantly lower than that found by traditional interpretation of leak-off or extended leak-off tests.The flowback test with volume measurements should be the preferred method of performing leak-off tests for precise routine stress determination in deep wells.