Hydraulic Fracturing Simulation for Fracture Networks

The term ‘Unconventional Reservoirs’ is used in the oil and gas industry for hydrocarbon reservoirs that have very low permeability in the magnitude of microdarcy (μd) and therefore rely on artificially introducing pathways for fluids and gases, commonly by using hydraulic fracturing techniques, to enable economic production. This approach of using fracturing stimulation campaigns is also increasingly used to improve production in mature oil and gas fields. Industry estimates for North America indicate that more than half of all stimulation treatments have no impact on production, despite this technique having been in use in numerous onshore wells for more than a decade. Creating fractures connecting the source rocks to the well whilst allowing fluids to flow, either with new hydraulic fractures and/or activating existing natural fracture sets can have a large impact on production. Optimising the current approach based on determining its many parameters and adapting experience based knowledge to other regions in the world poses a complex challenge with the goal to understand and predict the effectiveness of the stimulation campaigns. Significant progress in the simulation of fluid driven crack propagation for a single fracture occurred with recent updates of Abaqus capabilities including coupled fracture and pore fluid flows with porous medium deformation. This paper looks at the challenges using different modelling approaches using Abaqus such as Cohesive Elements (COH), Extended Finite Element Method (XFEM), Smooth Particle Hydrodynamics (SPH) and coupled Eulerian Lagrangian methods (CEL) with the goal to extend applications to more complex geometries with interaction of multiple fractures and stress shadowing effects.