Laboratory Measurements and Estimates of the Biot Coefficient of a Pre-Salt Oil Field, Santos Basin

Abstract

The Biot’s coefficient is an important parameter in geomechanical models of hydrocarbon reservoirs, with direct influence over the stress distribution in space and time along the production history. We conducted stress-strain experiments (quasi-static measurements) to measure the Biot coefficient of rock samples from an oil field in the Santos Basin. We found strong correlations between these quasi-static measurements and the estimates from dry rock ultrasonic elastic velocities (dynamic measurements). Additionally, we observed good correlations between the Biot’s coefficients and the effective porosity of the rocks, as well as with the acoustic impedances. These findings suggest that it is possible to derive poroelastic parameter logs of Biot’s coefficient in well locations, which can be used as input for geostatistical interpolation between wells. This would help in constructing more accurate reservoir geomechanical models and may even enable the generation of a three-dimensional distribution of the coefficient based on acoustic inversion of seismic data.