Welcome to the next PoreLab lecture!
Who: Dr. Bérénice Vallier from the University of Strasbourg, France
When: Thursday December 14 at 13:00 (Norway time).
Where:
The lecture will be streamed in the Kelvin room (PoreLab Oslo) and in the common room (PoreLab Trondheim). From anywhere else, you will be able to join via the following Zoom link:
https://uio.zoom.us/j/65837085049?pwd=WjZianUyN3FJa2liQkxBbzQrOCtGdz09
Title: Influence of pumping strategies on the induced seismicity from pressure disturbances on faults during well injections
Abstract:
Authors:
B. Vallier (1), R. Toussaint (1), M. Fahs (1), C. Baujard (2), A. Genter (2), E. G. Flekkøy (3), K. J. Måløy (3)
(1) ITES, University of Strasbourg / CNRS, 5 rue René Descartes, Strasbourg, FRANCE
(2) ES Géothermie, 5 rue Ampère, Mundolsheim, FRANCE
(3) SFF Porelab, Njord, Physics Dept., University of Oslo, Sem Sælands vei 24, NORWAY
In the context of deep exploitation, there is the necessity to enhance the reservoir permeability before exploitation. To enhance the permeability, one way is to conduct stimulations by fluid injection which increase the pore pressure. However, this method can generate an increase of the induced seismicity. The main goal of this work is to prevent induced seismicity from critically stressed distant faults by minimizing the pressure disturbances at distance due to well injections. A numerical model based on the finite difference method is developed to solve the diffusion equation of the pressure disturbances. The domain is assumed to be isotropic and homogeneous. The 2D domain represents the fault plane and permeable damaged zone embedded in a less permeable rock in 2D. We also perform simulations in the homogeneous sedimentary reservoir using 3D modeling. The numerical model is validated by comparing the numerical distant pressure disturbances to analytical solutions developed from the Green’s function of diffusion equation. The numerical model is then used to investigate the influence of a different fluid injection/production strategy (time-dependent injection) on the near-well and distant pressure disturbances. The performances of different pumping strategies are compared at an equivalent level of pressure close to the well in the region targeted for simulation. The results show that the oscillating pumping strategy has a significant potential in reducing the induced seismicity on distant faults. Further works including models of increasing complexity with more realistic fault geometries and operational conditions will be conducted for mitigation strategies.