Modeling and optimization of the stimulated reservoir volume by variable-rate displacement fracturing in shale oil reservoirs

Hydraulic fracturing technology is widely applied in the development of unconventional oil and gas resources. However, traditional fracturing methods face challenges such as limited capability to form complex fracture networks and inadequate communication with remote well zones. Although previous studies have explored fracture propagation and pump rate optimization, they predominantly focus on the impact of constant pumping rates on fracturing effectiveness in homogeneous reservoirs in horizontal wells, lacking in-depth investigation into the mechanism of stimulated reservoir volume (SRV) maximization through variable pumping rates and the optimal timing of rate variations in shale reservoirs with natural fractures. Therefore, we first built an interaction model between hydraulic fractures and natural fractures and then analyzed the influence of variable pumping rates on the interaction with the typical parameters of X Block in Subei Basin. Using response surface methodology (RSM), a series of numerical simulations were conducted, and factors affecting SRV were fully investigated. Results show that variable pumping rates will increase SRV by 17% more than constant pumping rates. This approach provides theoretical and practical guidance for optimizing pumping rates in hydraulic fracturing operations, which improves the performance of hydraulic fracturing and shale oil production.