Figure F10. Gamma ray (NGR) and resistivity logs, core and log porosities, and in situ pressures at M.C. 810 Ursa geotechnical well 1. The Blue Unit (light gray) lies between 300 and 550 mbsf and is composed of interbedded sandstone and mudstone layers. Core porosity (ϕcore) declines rapidly with depth to 200 mbsf and thereafter is constant. Overpressure (P* = P – Ph) is plotted; thus the vertical axis is hydrostatic pressure (Ph) and the right boundary of the plot is the reduced lithostatic pressure (σv* = σv – Ph). Circles = piezoprobe pressures, triangles = preconsolidation pressures from uniaxial consolidation tests of core, stars = pressure measurements inferred from pressure while driling (PWD) in the Blue Unit. Ostermeier et al. (2000) and Eaton (1999) further describe these data.
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