Impact of fluid rheology on the deformation dynamics of a vertical wellbore in an anisotropic matrix

Extracting hydrocarbon resources such as shale oil or gas from unconventional reservoirs is challenging due to the low-permeability nature of shale rocks. Shale rocks, often known as tight sandstone formations that comprise high and low permeability layer formations, exhibit varied material characteristics. The hydraulic fracturing (HF) technique is most commonly used to improve shale oil and gas extraction from unconventional reservoirs. Using this method, fracture propagation or development across a horizontal wellbore has been extensively researched recently. However, vertical wellbores have received less attention, particularly in anisotropic rock types, due to their varying modulus values at the layer interface, resulting in a significant research gap particularly in understanding the fluid-solid interaction during fracture evolution. The current research investigates fracture initiation and propagation using vertical wells bored into homogeneous and heterogeneous elastic matrix analogue samples (gelatin), with the effects of injecting fluid rheology and flow rates on fracture behavior at the laboratory scale. The numerical simulations were performed using a phase field model approach (FEM) to validate the experimental observations of fracture evolution. The main objective of this work is to enhance the understanding of fracture propagation and network development in complex geological formations with potential applications in CO₂ sequestration and gas hydrates.