Optimising Flowback Strategies in Unconventional Reservoirs: The Critical Role of Capillary Forces and Fluid Dynamics

This study delves into the complexities of fluid cleanup processes post-hydraulic fracturing in unconventional gas deposits, focusing on the pivotal role of capillary pressure (Pc) correlations in tight and ultra-tight formations. Utilising Geo2Flow software, this research evaluates the efficacy of existing Pc models, identifying the Brooks and Corey model as notably precise for these formations, albeit recommending an adjustment to the pore size distribution index for a more accurate representation of rock behaviours. Further investigation centres on the cleanup process in multiple fractured horizontal wells, examining the impact of the Pc, matrix permeability, drawdown pressure, and fracturing fluid volume. A significant portion of this study addresses the influence of interfacial tension-reducing chemicals on post-fracturing production, highlighting their utility in ultra-tight formations, but advising against their use in tight formations due to environmental concerns and limited efficacy. The findings underscore the nuanced interplay between geological parameters and fracturing fluid dynamics, advocating for tailored fluid cleanup strategies that enhance the hydraulic fracturing efficiency while minimising the environmental impact. This comprehensive analysis offers valuable insights into optimising fracture cleanup and understanding the underlying physics, thereby contributing to more effective hydraulic fracturing practices.