Inverse modeling of stress from well data in a reservoir containing mechanical heterogeneities.

Marianne Conin and Antoine Mazuyer and Richard Giot and Guillaume Caumon. ( 2014 )
in: Proc. 34th Gocad Meeting, Nancy

Abstract

Stress estimation in a reservoir is a fundamental task to assess the interaction between rock and fluids (hydrofracturing, fault reactivation, fluid circulation). In homogeneous media, dimly anisotropic and dimly deformed, regional stress can be estimated from present day loading conditions (gravity and tectonic far-field loading). Those estimates become unreliable when the media contains anisotropies or mechanical heterogeneities which modify significantly the local state of stress. This work aims at estimating the effect of theses heterogeneities on the state of stress. At first we model stresses in a benchmark grid containing a fault and 3 folded layers of known mechanical properties, a given far field loading, and a series of wells providing measurements of stress (orientation and magnitude). This first step is to map the local variations of stresses around discontinuities, and quantify the effects of each discontinuity as well as the combined effects of several discontinuities on the state of stress. This is made with a finite element code. The second step is to invert stress data measured in the wells to constrain the mechanical properties of each discontinuity. Results provide a characterization of the mechanical compartmentalization of the reservoir, and a prediction of the mechanical response of the reservoir to a new drill site or a change in the mechanical properties of a discontinuity.

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BibTeX Reference

@INPROCEEDINGS{ConinGM2014,
    author = { Conin, Marianne and Mazuyer, Antoine and Giot, Richard and Caumon, Guillaume },
     title = { Inverse modeling of stress from well data in a reservoir containing mechanical heterogeneities. },
 booktitle = { Proc. 34th Gocad Meeting, Nancy },
      year = { 2014 },
  abstract = { Stress estimation in a reservoir is a fundamental task to assess the interaction between rock and fluids (hydrofracturing, fault reactivation, fluid circulation). In homogeneous media, dimly anisotropic and dimly deformed, regional stress can be estimated from present day loading conditions (gravity and tectonic far-field loading). Those estimates become unreliable when the media contains anisotropies or mechanical heterogeneities which modify significantly the local state of stress. This work aims at estimating the effect of theses heterogeneities on the state of stress.
At first we model stresses in a benchmark grid containing a fault and 3 folded layers of known mechanical properties, a given far field loading, and a series of wells providing measurements of stress (orientation and magnitude). This first step is to map the local variations of stresses around discontinuities, and quantify the effects of each discontinuity as well as the combined effects of several discontinuities on the state of stress. This is made with a finite element code. The second step is to invert stress data measured in the wells to constrain the mechanical properties of each discontinuity. Results provide a characterization of the mechanical compartmentalization of the reservoir, and a prediction of the mechanical response of the reservoir to a new drill site or a change in the mechanical properties of a discontinuity. }
}