Study on pressure propagation characteristics of low permeability core seepage flow

Learning more about flow characteristics of low permeability reservoir is significant to develop low permeability oil field cost-effectively.One-meter-long outcrop seepage flow simulator was set up to study the dynamic pressure propagation under the condition of single phase seepage flow and water flooding with constant differential pressure.End effect in short core simulator was eliminated and the seepage characteristics of low permeability reservoir were revealed in this paper.It's showed that,in the single phase water seepage flow experiment,the permeability parameter of low permeability formation is not a constant value but the function of fluid's pressure in the pore,and the pressure distribution within the long core is non-linear along the flow direction.With drainage differential pressure increase,the non-linear tendency of pressure distribution becomes stronger.Due to stress sensitivity,pressure loss is mainly near to the production well.Constant differential pressure water flooding experiment showed that,seepage resistance loss is mainly in oil-water two-phase zone.When water/oil front arriving the pressure taps,their pressure declines gradually.After water/oil front passes those taps,their pressure begins to increase.