PREDICTION OF THE ACOUSTIC VELOCITIES, ELECTRICAL AND THERMAL CONDUCTIVITIES OF CARBONATE FORMATIONS APPLYING SELF-CONSISTENT METHODS.

摘要

In this paper we study the influence of a pore-space microstructure on the physical parameters of double porosity carbonate formations. We have calculated the elastic-wave velocities, electrical and thermal conductivities applying two self-consistent methods: the effective medium approximation and differential effective medium. The double porosity media is considered as a heterogeneous material composed by a homogeneous isotropic matrix with the primary small-scale pores and the large-scale inclusions as secondary pores. Inclusions are randomly orientated and arbitrarily distributed in the matrix. All components of this medium (solid grains, primary and secondary pores) are approximated by three-axial ellipsoids. Variations of the inclusion aspect ratios which define the secondary pore shapes allow simulating different secondary porosity types. We have calculated the effective medium parameters as functions of the values and types of the secondary porosity. Additionally, we consider the influence of a bimodal distribution of the secondary-pore shapes on the studied parameters. The results obtained are the theoretical basis for the petrophysical inversion of well log data for the separated determination of the primary and secondary porosity in carbonate formations.