Surface Phenomena Effects on Seismic Attenuation and Stiffness of Partially-saturated Rock
Event name: 80th EAGE Conference and Exhibition 2018
Session: Poster: Rock Physics C - Saturation and Attenuation
Publication date: 11 June 2018
Info: Extended abstract, PDF ( 574.71Kb )
Price: € 20
king place on the interfaces between gas, liquid and solid: 1) The presence of interface menisci and the contact-line pinning effects restrict the relative motion of the fluids during wave-induced two-phase fluid flow, causing increase in the effective stiffness of a partially-saturated rock. 2) Wettability-dependent Stoke’s no-slip boundary condition may not always apply in sub-microns pores and at the contact line location, causing the fluid molecule to slip and roll over the surface of solid. This reduces the effective stiffness of a partially-saturated rock and causes the attenuation of wave energy. Published experimental data suggests that physicochemical interactions cannot be explained by Gassmann’s, Biot’s and squirt-flow models. In this paper, we propose a new rock-physics model which provides a theoretical foundation for the above two hypotheses and explains the dependence of stiffness and attenuation on the amplitude of seismic wave, stress and the compressibilities of pore fluids. The model is based on modern concepts of the physics of wetting and a newly-published analytical solution for stresses and displacements around a partially-saturated crack.