Elastic piezosensitivity of porous and fractured rocks

Abstract

Understanding the stress dependencies of seismic velocities is important for interpreting a variety of seismic data, ranging from amplitude versus offset (AVO) and velocity analysis to overpressure prediction and 4D seismic monitoring of reservoirs. Sometimes, rather complex forms of these dependencies based on specific models of porous space geometry are used. For example, spherical contacts models (Duffy and Mindlin, 1957; Merkel et al., 2001) Duffy Merkel 2001 and crack contacts models (Gangi and Carlson, 1996; Carcione and Tinivella, 2001) have been used in different studies. Gangi96 However, usually the pore-pressure velocity dependence along with the velocity dependence on the confining pressure are phenomenologically described by the following simple relationship (Zimmerman et al., 1986; Eberhart-Phillips et al., 1989; Freund, 1992; Jones, 1992; Prasad and Manghnani, 1997; Khaksar et al., 1999; Carcione and Tinivella, 2001; Kirstetter and MacBeth, 2001)