Geomechanics and its interaction with flow

Ignoring geomechanical effects can lead to inaccurate predictions of injectivity, fracture propagation, or caprock integrity. Accurate coupling of flow and mechanics is vital for safe and efficient subsurface operations, especially in structurally complex reservoirs.

What do we do?

We develop robust numerical methods and software for simulating coupled flow and geomechanics, with a focus on:

• Consistent discretizations for mechanical deformation: Implementing methods like the Virtual Element Method (VEM) and Multi-Point Stress Approximation (MPSA) to ensure accuracy on unstructured grids.
• Coupling strategies: Employing fully implicit, sequential, and staggered schemes to balance computational efficiency and accuracy.
• Unstructured and conformal grids: Designing robust discretization schemes for grids that accurately represent complex geological settings, including faults and fractures (i.e., grids that are not triangular/tetrahedral).
• Error indicators and benchmarking: Developing tools to assess discretization errors and benchmark different schemes for reliability.
• Integration with flow solvers: Coupling mechanical models with multiphase and compositional flow solvers for comprehensive simulations.

Applications

• CO₂ injection and storage
  Simulation of geomechanical effects during CO₂ injection to assess reservoir deformation, caprock integrity, and fault stability, ensuring safe and long-term storage.
• Hydraulic fracturing and fracture propagation
  Modeling fracture initiation and growth by coupling fluid flow with rock mechanics to optimize fracture design and predict induced seismicity.
• Reservoir compaction and subsidence
  Prediction of surface subsidence and compaction due to fluid withdrawal, integrating coupled flow and mechanical deformation for infrastructure risk assessment.
• Fault reactivation and caprock integrity
  Evaluation of mechanical stresses on faults and sealing formations under changing reservoir pressures to prevent leakage and maintain storage security.
• Injectivity: Modeling how mechanical deformation and fracture propagation impacts injectivity in reservoirs, enabling prediction and mitigation of formation damage or permeability changes during injection operations to optimize flow rates and operational efficiency.
• Automated calibration of geomechanical parameters: Inversion workflows and optimization techniques for estimating rock mechanical properties and far-field stress conditions from observed data, supporting improved model fidelity and uncertainty quantification in geomechanical simulations.

Selected contributions

• Development of consistent discretizations for unstructured grids and published as open source software (e.g., the MPSA module in MRST).
• Coupled flow-geomechanical simulation frameworks for industry partners.
• Benchmarking of discretization schemes for fractured reservoirs.

References

• O. Andersen, M. Kelley, V. Smith, and S. Raziperchikolaee. Automatic Calibration of a Geomechanical Model from Sparse Data for Estimating Stress in Deep Geological Formations. SPE Journal, 2021, 27(02): 1140–1159. DOI: 10.2118/204006-PA
• O. Andersen. A Brief Introduction to Poroelasticity and Simulation of Coupled Geomechanics and Flow in MRST. In: K.-A. Lie and O. Møyner (eds), Advanced Modeling with the MATLAB Reservoir Simulation Toolbox, Cambridge University Press, 2021, pp. 549–596. DOI: 10.1017/9781009019781.020
• O. Andersen, H. M. Nilsen, and S. E. Gasda. Vertical Equilibrium Flow Models with Fully Coupled Geomechanics for CO₂ Storage Modeling, Using Precomputed Mechanical Response Functions. Energy Procedia, Volume 114, July 2017, Pages 3113–3131. DOI: 10.1016/j.egypro.2017.03.1440
• O. Andersen, H. M. Nilsen, and S. E. Gasda. Modeling geomechanical impact of fluid storage in poroelastic media using precomputed response functions. Computational Geosciences, 2017, 21: 1135–1156. DOI: 10.1007/s10596-017-9674-8
• O. Andersen, H. M. Nilsen, and X. Raynaud. Virtual element method for geomechanical simulations of reservoir models. Computational Geosciences, 2017, 21: 877–893. DOI: 10.1007/s10596-017-9636-1
• O. Andersen, H. M. Nilsen, and X. Raynaud. Coupled Geomechanics and Flow Simulation on Corner-Point and Polyhedral Grids. SPE Reservoir Simulation Conference, Montgomery, Texas, USA, February 2017. DOI: 10.2118/182690-MS
• O. A. Andersen, H. M. Nilsen, and S. E. Gasda. Modelling Geomechanical Impact of CO₂ Injection and Migration Using Precomputed Response Functions. ECMOR XV - 15th European Conference on the Mathematics of Oil Recovery, Aug 2016. DOI: 10.3997/2214-4609.201601760