AN EVALUATION OF MECHANICAL PROPERTIES OF THE PHOSPHORIA FORMATION AND THE MANCOS SHALE USING WIRE-LINE GEOPHYSICAL DATA

This research evaluates the elastic moduli and mechanical strength of the Phosphoria Formation and Mancos Shale in Utah and eastern Idaho to quantify the effects changes in mechanical rock properties have on fine grained rock during changing stress conditions and the potential for fracture formation. Poisson’s Ratio and Young’s Modulus are used to characterize mechanical properties and were derived from geophysical wireline data including density (ρ) logs and sonic logs in 18 boreholes. Of these boreholes, 7 were chosen for this project due to some of the Young’s Modulus logs resulting in negative numbers. Sonic logs were used to calculate compressional velocity (V_p) and density for 5 of the wells that were missing density logs. We use Young’s modulus to describe the stiffness of the source rock and Poisson’s Ration to describe shape change in response to stress. Using elastic moduli in combination with gamma ray, a lithology log, to identify areas prone to open mode facture propagation, allowing migration from the source rock or production from these unconventional resources.