Pore pressure and in-situ stress magnitudes in the Bhiret Hammou hydrocarbon field, Berkine Basin, Algeria

Abstract

A recently drilled exploratory well encompassing over 5 km of Mesozoic and Paleozoic sediments has been studied from the Bhiret Hammou field of the Berkine Basin, Algeria. Geophysical logs and downhole measurements have been integrated to ascertain rock strength, elastic properties, pore pressure and principal in-situ stress magnitudes. Vertical stress has an average 1.02 PSI/feet gradient in the studied field, as estimated from the density log. The Devonian shales are mildly over-pressured, while the Triassic and Carboniferous hydrocarbon reservoirs are in a hydrostatic pore pressure regime. Minimum and maximum horizontal stresses are quantified from a poroelastic strain model. The Sh gradient varies between 0.59 and 0.80 PSI/feet, whereas the SH gradient is interpreted as 0.86–1.26 PSI/feet. Based on the relative stress magnitudes (SH≥Sv>Sh), a present-day normal to strike-slip transitional tectonic regime is inferred