Minimum in-situ stress measurement using temperature signatures

This study proposes a method to determine the temperature signature that can delineate the closure of a fracture, and infer closure stress from the bottomhole pressure that coincides with this signature. After shut-in, the fluid leaks off into the formation through an effective matrix comprised of native permeability and flow through natural or induced fractures. This flow from a conceptualized main fracture is accompanied by advective heat transfer away from the wellbore and advective movement of cooler fluid from the wellbore into the fracture. Considering the analog situation for pressure, the G function (a function defined by pumping and shut-in time) with temperature history has been used to account for the shut-in period. The change of temperature before and after fracture closure results in characteristic inflection points on a plot of GdT/dG vs G, suggesting closure of the primary fracture and providing an indication of the total stress normal to that fracture.