A Study Of Well Test Analysis For A Reservoir With Polymer Flooding

The pressure response curves of many oil and water wells under polymer flooding have been accumulated since industrializing application of polymer flooding technique from 1996 in Daqing oil field. Compared to the curves under water flooding, it has obvious particularity. The semilog curves become steep in early time and afterflow period becomes longer. The influence of boundary on long time lags and the slope of radial flow straight-line increases. The derivative curve of log-log curve, which corresponds to the 0.5 characteristic line, is a straight line with certain slope and the slope becomes larger with the injection of polymer.Based on the achievements about the fluid flow in porous media and well test, the following researches have been done in point to the particularity of pressure buildup curve under polymer flooding.1. The changing law of polymer solution concentration between injection well and production well has been given through using POLYMER numerical simulation software with the object of quarter well group of five-spot pattern.2. According to the relations of power-law index and polymer concentration obtained by constructed other scholars, combined with the polymer concentration distribution law, the calculating method of power-law index is developed. Applying the arithmetic to computer software solved the problem that power-law index is difficult to obtain in primary theory.3. New percolation flow model has been established by applying a new effective viscosity model in well test interpretation model. In the new viscosity model, the influences of polymer property, concentration and rehology are considered. And we obtained the numerical solution of the well test and the typical curves. New well test model considering variety of polymer concentration has been presented in a form that suitable for interpreting the parameters well and truly.4. "Song I" method for Non-Newtonian fluid flow has been proposed and its simplified express while power law index approach to 1 has been given.5. We have worked out a well test interpretation software of high standardization that is suitable for the production practice and can be operated conveniently. Examples for some oil and water wells in polymer flooding blocks of Daqing oil field are given.