Numerical Simulation of Fracking in Shale Rocks: Current State and Future Approaches.

Area of Science:

• Geological Engineering
• Petroleum Engineering
• Computational Mechanics

Background:

• Shale gas extraction presents engineering challenges, necessitating accurate fracture modeling.
• Current models often simplify shale as isotropic, which recent research shows is inaccurate.
• Shale anisotropy varies with scale (nano, micro, macro), requiring multiscale approaches.

Purpose of the Study:

• To provide an overview of hydraulic fracturing in shale.
• To introduce recent findings on shale rock anisotropy.
• To present numerical methods for modeling complex fracking scenarios.

Main Methods:

• Literature review of shale characterization and anisotropy.
• Exploration of multiscale modeling concepts.
• Discussion of numerical discretisation methods for crack propagation.

Main Results:

• Shale is an anisotropic material, with anisotropy dependent on scale.
• Hydraulic fracture propagation in shale is complex, involving potential branching and multiple crack interactions.
• Existing numerical methods may face challenges in accurately modeling these complex phenomena.

Conclusions:

• Accurate modeling of shale hydraulic fracturing requires accounting for material anisotropy.
• Multiscale models are necessary to capture the scale-dependent nature of shale properties.
• Advanced numerical methods are needed to simulate complex crack propagation in shale.