Antoine Mazuyer

Reservoir stress estimation by Inverse approach

Description: The goal of my Ph. D is to estimate the reservoir stress field before the exploitation.

The aim of my ph.D is to estimate the initial stress in reservoirs before production using 3D calibrated geomechanical models. I propose an inverse method for estimating stress. Wellbore data (such as calliper logs measuring the deformation) can be integrated in a Mechanical.Earth Model in order to estimate stresses nearby wells. From this rough stress field, the inversion aims at finding a physically acceptable stress state (i.e.: in equilibrium with the external forces and boundary conditions) that fit the local stress at the wells. The forward problem is ensured by a Finite Element Analysis which is able to take into account structures such as faults, which have a significant influence on the stress magnitude and orientation. Inverse loop stops when the stress computed near wells matches the one estimated using borehole data. The uncertainties on the boundary conditions, elastic parameters and the first stress estimation are taken into account with a stochastic approach.