Hydraulic fracturing stress measurements in an inclined hole in South Carolina and their application to underground cavern design

A recent set of hydraulic fracturing stress measurements in a steeply inclined borehole in Northern South Carolina, has revealed some important facts about the reliability of the method in non-vertical holes yielding non-vertical fractures, and about in situ stress magnitudes at shallow depths (100-250 m). Fourteen hydraulic fracturing tests conducted in the 250 m borehole revealed a state of high horizontal stresses with the maximum stress direction at N66°E. This state of stress was verified by two independent methods of data analysis, and by comparing it with previous results in the vicinity of the test hole as well as in the entire tectonic region. Several unusual test results which may have considerable significance in design are discussed.