In the context of fluid-induced seismicity, various injection parameters have been shown to affect fault behaviour differently, although existing studies about their effects sometimes show contradictory results. Aseismic slip is also known to affect seismicity, but its exact contribution remains elusive. To address these, we perform numerical modelling to understand the effects of injection volume and rate on long-term seismic and aseismic fault slip behavior. Our results suggest that both parameters can affect various aspects of fault behaviour to different extents and their roles are interdependent, thus they should be examined simultaneously. We observe the fault predominantly releasing aseismic energy, which plays a significant role in altering the timing of triggered earthquakes that follow and exhibit lasting impacts in subsequent seismic cycles. In terms of seismic responses, the number of events in the triggered cluster is primarily controlled by the injection rate, and the seismicity rate by the injected volume.