Research On Layered Regulating And Testing Technology In Polymer Flooding Well

With the development of tertiary oil recovery, polymer flooding is widelyexpanded in China. As a key technology in polymer flooding, layered regulating andtesting technology solves the interlayer contradiction, and plays a significant role inenhancing petroleum recovery efficiency. In separate layer production of polymerinjection wells, as important equipment, the performance of eccentric injectiondevice will determine the effect of oil production in polymer flooding well.However, polymer solution is a kind of non-Newtonian fluid or pseudo-plastic fluid.And when it flows across the injection device, it will suffer a mechanical shearingwhich leads to the viscosity loss, while the viscosity loss can reduce the oilproduction. There are still some problems that limit the enhancing of oil recovery inavailable injection device, such as complex casting fishing, serious shearing anddegradation of polymer solution, un-adjustable injection volume and so on.On the basis of comprehensive analysis of the merits and demerits of injectiondevice at home and abroad, this article proposed an electronic control solution. Itconsists of an electric actuator, a pressure regulation component, sealing elementsand cable connectors. The electric actuator utilizes the motor and reducer to drivethe lead screw nut; the pressure regulation component is a shape-optimized valvecore; the sealing elements and the cable connectors are used to guarantee the seal ofthe injection device. The structure of electronic control makes the valve coremovable in the eccentric channel to change the valid pitch number to realize thecontinuous adjustment of the injection volume, and it can also limit the injectionvolume of the high permeability layer. Based on the overall mechanical design,strength and deflection analysis of key components was done, and a sample machinewas made at last. If this mechanism were installed to different layers, the injectionvolume of each layer would be adjusted in real time on the ground.Based on the non-Newtonian fluid mechanics, the flow law in annular space ofpolymer solution was studied theoretically; theoretical analysis was done on laminarflow and turbulent flow in pipe and annular channel; the velocity distribution anddischarge-head relation of the power law fluid was obtained. The valve core channel model of the eccentric injection device was developed through GAMBIT, and a flowfield simulation was done by using FLUENT combined with the governing equation,then the changing regularity of pressure difference was analytically investigated.After the dynamic simulation analysis, an optimization design of the valve core wasdone.In order to prove the function of the pressure regulation component, a separateexperiment of the valve core was carried out to analyze the influence of the differentinjection volume on the velocity loss rate and the throttle pressure difference. Afitting curve of injection volume and pressure difference was calculated, and theinstinct parameters of the polymer solution were obtained. A heavy pressureexperiment with a view to verify the sealing effect was carried out indoor. In the end,an underground experiment was launched after the connecting of the eccentricinjection device and the packer; by collecting the pressure data the discharge-headrelation was acquired. The results of the simulation and the experiment werecompared and an error analysis was carried out.