<p>In some unconventional oil and gas reservoirs, the abundant presence of natural fractures (NFs) leads to highly complex propagation behaviors of multi-cluster hydraulic fractures (HFs). In this paper, a new numerical model is established for simulating multi-cluster HF propagation in fractured reservoirs, incorporating NF types (broadly classified by mechanical properties into frictional and cemented), NF random distribution, multi-cluster HF competitive propagation, and HF–NF interactions. Sensitivity analysis of the geological and engineering parameters reveals the propagation behaviors of multi-cluster HFs in reservoirs with frictional and cemented NFs and the associated mechanisms. In scenarios of low horizontal stress difference, small NF strike angle, low NF strength, low injection rate, and low fracturing fluid viscosity, HFs are prone to diverting along NFs, resulting in increased propagation resistance. The coupling effect of random interference from NF groups and stress shadow effects result in uneven growth of HFs among different perforation clusters and between both sides of the same perforation cluster, accompanied by fluctuations in the injection pressure curves. HFs tend to extend further along frictional NFs than cemented NFs, leading to more severe issues with the uneven development of multi-cluster HFs and larger fluctuations in the injection pressure curve, but it facilitates the formation of a complex HF network. A combined fracturing fluid of “gel fluid + slick water” is recommended for field applications, because high-viscosity fluids promote the balanced development of multi-cluster main HFs, while low-viscosity fluids help complicate the HF network by inducing shear activation of NFs into branch fractures.</p>