论文部分内容阅读
A series of polymer flooding pilots was conducted in the Daqing oilfield.The polymer concentration in these pilots was higher than average, generally more than 2000mg/L, exploiting its high viscoelasticity to further increase the micro-scale oil displacement efficiency.A history-matching simulation was carried out for the high-concentration polymer flood pilots, showing that because the adopted simulator could not simulate the process mechanism of polymer elasticity, the production performance could not be matched when the residual oil saturation value of the polymer flooding was the same as that for water flooding.In order to achieve good history matching for high-concentration polymer flooding, we modeled the polymer elasticity process mechanism based on the laboratory study results, which showed that the polymer elasticity process could decrease the residual oil saturation value below that of water flooding, therefore increasing the relative permeability of the oleic phase.Based on these results, we constructed a 3-D, 3-phase (oil-gas-water) polymer flooding mathematical model.A sequential-like solution scheme was devised to obtain a fast,highly stable solution for the polymer flooding mathematical model.A polymer flooding simulator was developed that has the ability to simulate the process mechanism of polymer elasticity.The simulator can model the other main polymer flooding process mechanisms, such as aqueous viscosity depending on polymer concentration, polymer solution rheology, polymer permeability reduction, inaccessible volume and adsorption.The simulator was applied to high-concentration polymer flooding in the Daqing oilfield, and the production performance was matched very well by reducing the residual oil saturation below that of water flooding.The research results suggest that: (1) high-concentration polymer flooding can not only expand the sweep efficiency, but also increase the micro-scale oil displacement efficiency;(2) the newly developed simulator can suitably simulate the process of polymer elasticity.