The Study Of Transmission Of Pressure In Low-permeable Reservoir

It's hard to inject water into the low permeability reservoir,even if the injection pressure is high,the injection pressure isn't in proportion to the flow rate.The transmission of pressure in low permeability reservoirs is different from the conventional reservoirs.The study of the transmission of pressure in low permeability reservoirs is very important to design the water injection rate. Lots of the experimental datas have indicated that,when fluid flows in the low permeability reservoirs,if the pressure is greater than the min-threshold pressure and less than the max-threshold pressure,it's a non-linear flowing. however,most of the models still have ignored it,then the models cant't discribe the distribution and the transmission of the pressure.So the study of the transmission of the pressure which considered the non-liner flowing in low permeability reservoir is significant.In this paper,a three-section method is builted on the base of lots of of the experimental datas,and this method can decreasing modeling and solving difficulty,and the mathematical precision is guaranteed. A single dimension unsteady flow model is built on the base on the equation which is built to describe the state of the fluid flows in the low permeability reservoirs.In this paper,the successive steady-state replacement method is used to solved the unsteady state flow model,and get the distribution of pressure.The result said that,the three-section method can lower the diffculty when a quadratic equation is considered,and with a good Precision.The eqution of the distribution of pressure considers the pseudo-threshold pressure only,the min,max-threshold pressure,and the facters which relate to the viscosity,permeability are considered either. The equition of motion,distribution of pressure and the radius of influence which are got through the three-section method are right,they can describe the law of the pressure transmission well.