It is difficult to obtain profitable production without the application of hydraulic fracturing in tight glutenites because of their ultra-low permeability.Profitable exploitation of glutenites requires a clear understanding of the hydraulic fracture propagation law in these reservoirs. Considering the heterogeneity of sandstone or gravel and the heterogeneity between sandstone and gravels，a numerical method that integrates the digital image processing technique into a numerical software named rock failure process analysis（RFPA）was proposed.Based on the method，two-dimensional simulation results of the fracturing in the tight glutenites indicate that hydraulic fractures can penetrate or deflect along the gravels depending on the conditions of stress differences and gravel strengths. Three-dimensional simulations considering gravel distribution orientation，gravel size and axial ratio reveal that the hydraulic fractures can penetrate gravels，resulting in a bypass fracture which is difficult to be observed in regular lab experiments，or deflect along the gravel which is similar to that observed in two-dimensional simulations. Main propagation modes under various gravel distribution orientation，size and axial ratio are as follows：①penetrate gravels directly；②deflect along the gravels；③bypass the gravels；④combination of①and②，or②and③.