Abstract: Based on the actual reservoir geology character，a large-scale visual sandbox physical model was designed to study
the flow mechanism in multi-layer sandstone reservoir directly. The effects of different injection methods and velocities on the
efficiency of water flooding and distribution of water and oil in the process of water flooding are studied. The model has a larger
size and a high degree of simulation，and visualization. It is more representative than other models. The model was designed
on the basis of sandstone strata in a block of NP Field，according to the principle of similar geometric，the same well-type，
sequence rhythm，and fluid viscosity，so that the simulation of underground conditions is more real. The real results show
that different injection methods and velocities have great effect on the recovery of the model. When there are more wells，and
single well controlled area is small，recovery will be highlightly；when the injection velocity is low，and water breakthrough
islate，water cut increases slowly，thich can effectively enhance oil recovery，and also reflects to gravitational differentiation.
The waterflood characteristic curve fitting shows that the new experiment meets water displacement feature，so it can predict
recoverable reserves and recovery accurately. This research presents a new physical simulation equipment，to help choose a
reasonable work system.

Key words: multi-layer sandstone reservoir, visual model, injection velocity, recovery predict, water flooding characteristiccurve