Research On Polymer Molecule Weight Adjusting Mechanism & Equipment

The polymer flooding in Daqing Oilfield was begun in 1970's, it has been industrialized in 1990's. Now Daqing Oilfield is the biggest polymer-flooding Oilfiled. Polymer injection practices had indicated: due to the effect of layer heterogeneous property, during general polymer injection, thick layers in the main reservoirs were exploited very well, while low permeable laminas were not exploited well. To further improve the oil recovery ratio of polymer flooding, separate layer injection is needed. After polymer flooding for main reservoirs, the object of polymer flooding in Daqing Oilfield has turned to the lower permeable laminas. Due to laminas'lower permeability, with more absorbing, and bigger coefficient of remains resistance, seepage capability drop and employ extent is lower in laminas, which affects polymer flooding effect. Molecule weight should be lowered appropriately to ensure no block in oil layers and has enough injection rate. Hereby the idea of different polymer molecule weight injection was brought forward. That is, for the low permeable laminas, polymer molecule weight can be reduced. So the technology can improve control extent of polymer injection and progress the whole development effect. According to mechanical principle, designed adjustable unit of nuzzle type. Through changing nuzzle diameter, controlled degraded intensity and degraded molecular weight. Through analyzing the principle of shearing polymer, we designed device for adjusting polymer molecule weight in order to realize polymer injection with different polymer molecule weight. By using device for adjusting polymer molecule weight, at precondition of injecting by single bump, single string and high polymer molecule weight, lower permeable layers can injecte lower molecular weight, the effect of oil extraction can be enhanced, at last, we achieve the goal of injection with different polymer molecule weight. We got essential hydraulics characteristic of device for adjusting polymer molecule weight through indoor experiment. And we got flooding effect and injecting pressure of sheared polymer and normal polymer solution through flooding experiment in core. Making use of dimension analyse principle and similitude principle, we got formula and relation curve ofΔηverse Q andΔP verse Q. Finally,based on the character of device for adjusting polymer molecule weight. we designed the eccentric mandrel molecular weight regulator. Through changing nuzzle diameter, we controlled degraded intensity. This device for adjusting polymer molecule weight is suitable to separate polymer injection inⅠ,Ⅱreservoirs, it will take very negative effect on improving the oil recovery ratio of polymer flooding.