Impact of Undrained Pore Pressure Response on Expected Failure Stress in Anisotropic Shales

• DOI: 10.56952/arma-2022-0672
• Publication Date: 2022-09-28T02:34:48Z
• Authors: M. I. Duda; R. M. Holt; J. F. Stenebråten; A. M. Stroisz
• Keywords: Poromechanics; Microseism; Effective stress; Overburden; Overburden pressure

ABSTRACT: The connection between undrained pore pressure response to stress in shales and fault reactivation, drilling problems microseismicity observed at significant distances from hydrocarbon reservoirs injection zones has not been thoroughly studied is usually disregarded geomechanical modelling workflows. In our study, we examine what extent the inclusion of affects amplitude total changes expected cause shear failure several overburden outcrop shales. We combine poroelastic coefficients Mohr-Coulomb envelope parameters estimated through triaxial laboratory experiments model increases for a wide range loading scenarios medium orientations. consider both isotropic anisotropic - explore differences outcomes two sets yield, as well impact individual on stresses failure. that significantly lower plausible much wider paths once considered, therefore postulate it should be taken into account during or production operations safety assessment. 1. INTRODUCTION Injection subsurface reservoir have documented lead activation, microseismic activity, borehole stability issues its surroundings (e.g., Pine et al., 1983; Raleigh 1976; Zoback & Harjes, 1997). some cases, these undesired phenomena occurred over-and underburden subjected change Odonne 1999; Rutqvist 2008; Segall, 1989). This triggered an ongoing discussion causes events. Until now, was primarily associated with fluid migration fractures planes throughout low permeable under- over-burden, transfer Vasco 2018; Verdon 2011; Williams-Stroud 2020; Zhou 2008) caused by injection- production-induced Geertsma, 1973; Morita 1989; Rudnicki, 1999).