The impact of layering and heterogeneity on stresses around boreholes

Abstract

An accurate understanding of orientation and magnitude of the stresses surrounding a borehole is decisive for the identification of a stable well path and the successful design of completions and stimulation measures including fracking stages. However, measurement of the in situ stress is challenging: Current engineering practice favours two approaches: 1) borehole break-out - drilling-induced fracture interpretation complemented by extended leak-off tests; 2) stress estimation from shear-wave slowness measured with advanced wireline tools. Both methods rely on the applicability of Kirsch's (1898) stress perturbation equations and laboratory measurements of elastic moduli that are correlated..