Fracture stimulation in the Cooper Basin has long been challenged by high near-wellbore pressure loss (NWBPL) present in hydraulic fracture treatments. Though many strategies have been applied to either mitigate or prevent this, the industry is still in need of a broadly applicable, economic and practical solution. An approach that has significant potential, and targets NWBPL from its foundation, is perforation design.
Perforation design has been shown in the past to have a significant effect on the initiation of a fracture and the success of its continued propagation. A commercial 3D hydraulic fracture simulator has been applied to data from Cooper Basin wells. These vertical wells contain tight sand intervals and are characterised by high differential stress. A sensitivity analysis has been performed using industry-standard GOHFER software, focusing on parameters including perforation diameter, shot density, interval length, number of intervals, and shot spacing.
Though many previous authors have suggested that perforation design has limited impact on pressure loss, the analysis performed in this study indicates that there are methods inherent in perforation design that can impact on high NWBPL. In particular, this study has noted a potential for many cost-saving strategies that could be applied to future completions.
This is an innovative study that examines the underlying links between perforation design and the resulting near-wellbore pressure loss. It focuses on problematic areas of the Cooper Basin in the hope that by examining these links useful recommendations can be made to the industry.
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