The calculation of caprock shale stress is important to maintain isolation between reservoir and overburden, as well as optimize reservoir completions and operating strategies. Continuous profiles ofstress can be calculated from well logs, but this requires some approximation to determine the full set oftransverse anisotropic parameters required in this process. In this study we model shales of varying silt content with and without horizontal cracks to understand the impact of a particular anisotropic approximation. It is found that the ANNIE approximation (δ = 0, C12C13 ) works well except when horizontal cracks are present, in which case it overestimates the overburden contribution to the horizontal stresses.

Presented at GeoConvention 2015.