Research On Pipe Flow And Pump Characteristics Of Polymer Flooding And Water Flooding Rod-pumped Well In Especially High Water-cut Stage

Oil pumping with sucker rod takes a large proportion in mechanical oil production, and is one of the main energy-consumption equipment. After entering especially high water-cut stage, many wells have a phenomenon that the load increases in up-stroke and decreases in down-stroke due to the change of the well-liquid characteristics which aggravates the eccentric wear level between sucker rod and oil pipe, reduces the pump inspection period and increases the energy consumption of pumping unit. In order to save energy and reduce consumption in oil pumping system, experimental research on pipe flow and pump characteristics of polymer flooding and water flooding rod-pumped well in especially high water-cut stage is developed, the main factors that influence pipe flow and pipe frictional resistance are analyzed systemically, which has provided scientific foundation to the design and management of oil pump well, and has a practical significance.In order to do research on pipe flow and pump characteristics of polymer flooding and water flooding rod-pumped well in especially high water-cut stage, rheometric test aimed at production stream from polymer flooding and water flooding rod-pumped well in especially high water-cut stage has been made, and the characteristic of production stream in especially high water-cut stage is confirmed as Newtonian fluid. Experiments using different mediums about pipe flow and pump characteristics is made. Frictional resistance and coefficient of friction resistance of annulus fluid between sucker rod and the pipe flow is calculated under different working conditions. Frictional resistance between plunger and pump barrel under different parameters is calculated based on related theory of pump characteristic and the strained analytical model of oil-well pump. Besides, using the theory of slit flow and hydraulic -clamping pressure, the frictional resistance is calculated, and the error between the result and measured value is no more than 13%. At last, the experimental data acquisition system is presented in this article.Viewpoint that the characteristic of production stream in especially high water-cut stage belongs to Newtonian fluid is proposed and testified in the test. Empirical formula of the oil viscosity in especially high water-cut stage has been put forward and the error to measured value is less than 15%.Detailed computation of different kinds of frictional resistance to the annulus fluid between sucker rod and the pipe flow is produced. The theory of slit flow and hydraulic -clamping pressure was applied in the calculation of the frictional resistance between plunger and pump barrel, and has been revised in order to be applied to reality. The main reasons that have an influence on the load increasing in up-stroke and decreasing in down-stroke in especially high water-cut stage are realized. That is because of the change of the density of well liquid. All these conclusions have a significant practical value to the improvement of engineering level to the oil field exploitation.