The comparison of hydraulic fracturing with two different staged methods: A numerical study

It is of great value to select a suitable stage fracturing method for the efficient development of the Kela Meili volcanic gas reservoir in Xinjiang. This study focuses on two fracturing techniques: sliding sleeve staged fracturing (SSSF) and staged fracturing with bridge plug (SFBP). A fluid–solid coupling fracture propagation program was developed based on the boundary element method, and a multi-stage fracturing numerical model was established to systematically investigate the effects of injection rate, fracturing fluid viscosity, Young's modulus, and horizontal principal stress difference (HSD) on pumping pressure, fracture morphology, fluid distribution, and stress field. The results show that the SFBP technique exhibits a 34.21% higher inter-stage pressure increase compared to the SSSF technique, demonstrating significant non-planar propagation characteristics. The range of mean fracture widths reaches 4.49 mm, with the dominant controlling factors ranked as follows: HSD > Young's modulus > injection rate > fluid viscosity. For the SSSF technique, fracture widths follow a progressive decrease across stages (with the widths of the second and third stages decreasing by 0.83 and 0.89 mm, respectively, compared to the first stage), achieving superior uniformity in fracture stimulation. The research results of this paper can provide a reference for the optimization of the stimulation mode of the target reservoir.