Numerical Simulation Of Flow State Of Injection And Production Zone In The Same Well And Its Influence On The Injection Pump

As the oil fields in China are entering the period of high water cut,the water cut of the oil fields developed by water injection is getting higher and higher.In order to maintain stable production,the water injection and production volume need to increase greatly.The comprehensive water cut in the placanticline of Daqing Oilfield has reached 95%,that is,20 tons of liquid should be produced for every 1 ton of oil produced.The trend of fluid production will increase faster and faster.The effect and economy of injection and production in the same well are investigated.According to the results of the survey,the research program is formulated.The same well injection and production technology can realize oil and water separation of produced fluid in the well.The separated water is injected back into the reservoir by an injection pump,while the higher oil-water mixture is lifted to the surface by a production pump.The implementation of this process can control ineffective fluid production,reduce the water output of the oil well,the production well can achieve economic and effective production,prolong the economic production life of the oil well,effectively increase the development cycle of the oil field,and improve the recovery factor under the condition that the production well reaches about 98% of the ultra-high water cut.This paper focuses on the discretization and solution of the equation of state of injection layer flow in the same injection-production well by using the computational fluid dynamics theory,and the program "computational simulation of injection layer flow in the same injection-production well" is compiled.According to the theory and method of computational fluid dynamics,the discrete equation of pressure distribution is obtained,and the solution method of the discrete equation is given.The computational simulation of injection layer flow in injection and production Wells of the same well is compiled by using VB6.0 development tool.The software can be according to the injection layer related parameters(hole diameter,the well spacing,formation permeability,porosity,reservoir thickness,stratum,static pressure,fluid viscosity and injection pump parameters(plunger diameter,small plunger diameter,sealing plug diameter,stroke,stroke)to calculate the required parameters,such as radial pressure distribution in the layer of the injection pressure,injection layer change law with time,The relationship between injection pressure and pump displacement.In addition,the calculation method of injection pump outlet pressure was established,and the variation law of injection pump outlet pressure with time and displacement was analyzed,and the influence of injection layer outlet pressure on pump load was analyzed.The calculation method of discharge flow of injection pump was established,and the discharge flow of injection pump was calculated and analyzed according to different stroke,stroke times and plunger diameter.Both theoretical analysis and numerical simulation results show that the formation pressure decreases with the increase of the distance from the bottom hole at the same time.At the same position,the formation pressure changes periodically with time,and the closer to the bottom hole or the longer the time of water injection,the greater the fluctuation range of the formation pressure is.The pressure fluctuation rises as a whole with the passage of time,that is,the average pressure in each cycle keeps increasing.Using single parameter,two parameter to quantitative and qualitative judgment mechanism of the influence of different parameters on the radial pressure,found that on the premise of different parameters,at different times,different radial location,double parameters at the same time the influence degree of the change,at the same time comparative analysis of different parameters on the injection pump load impact and influence on injection pump rate.