Investigating the Effects of Microscopic Elastic Parameters and Porosity on the Macroscopic Bulk Modulus of Reservoir Rocks

Please join us for a Graduate Student seminar this Friday February 8 at 3:30 pm in rm 155 Geology presented by Somtochukwu Ufondu, MSc candidate:

Investigating the Effects of Microscopic Elastic Parameters and Porosity on the Macroscopic Bulk Modulus of Reservoir Rocks

The mechanical parameters of rocks are those attributes that characterize their behaviour under mechanical loading - elastic/inelastic. A laboratory rock specimen is generally considered to be elastic (i.e., can return to its original shape after deformation when subjected to a load), homogeneous (i.e., of a uniform composition of minerals), and isotropic (i.e., having identical properties in all directions). These make for convenient calculations/approximations. However, the presence of fluids in porous rocks influences the way they respond to various stresses and deformations. Both the rock skeleton and the fluid within the pore are influenced by the stress in the solid skeleton caused by displacement at the outer boundaries of the rock, and the pore fluid pressure. These stress and pore pressure both cause a fractional change in volume (dilatation) of the material element of the rock (solid region) and a dilatation in the fluid region. This research aims to investigate the effect of microscopic elastic parameters and porosity on the macroscopic bulk modulus of porous rocks. In this study, and using two experiments, a macroscopic model was developed for simulating the dynamic stress-strain relations in porous rocks with saturating pore fluid, to compute the elastic potential (elastic energy density) and hence calculate the effective macroscopic bulk modulus, based on force balance equations for homogeneous, isotropic, and linear elastic medium.