The Alternation Of Polymer Flooding In Daqing Oil Field

Longitudinal or in an actual reservoir,the reservoir plane heterogeneity,prone to infuse water breakthrough in the process of water flooding and fingering phenomenon,cause the injection well production Wells in different directions around the uneven,and the oil line within the mainstream and non-mainstream online on oil displacement of heterogeneous.Chemical flooding,such as polymer chemical profile control and flooding technology can significantly improve the water flooding effect,but it is still affected by reservoir heterogeneity,after the application of these methods there are still a lot of remaining oil distribution is uneven status within the reservoir,the viscosity of oil displacement agent and the contradiction between the inhomogeneous reservoir remains unresolved.Paper uses the constant speed and constant pressure the idea of combining the two methods,the constant speed injection to calculate the resistance coefficient and residual resistance coefficient and constant pressure experiment it is concluded that the injection speed of three parameter combination,formulate the standards for judging oil displacement agent and reservoir injection line,summarizes the matching relation between each other,and gives the compatibility relation chart,got a different concentrations,different molecular weight of polymer and the matching relation between reservoir.After the permeability is respectively 100,300,500,300,500 and 1100 by 10-3 mu m2 parallel 6 artificial core and the polymer change alternately filtrational resistance system to improve recovery efficiency of indoor experiments.By comparing the different way and the alternate cycle plan Fen LiuLv alternately,recovery rate,moisture content and the change of parameters such as pressure,to inspect for the heterogeneity of alternate variable seepage resistance injection.Study found that the alternating injection can increase the low permeability layer suction fluid volume,adjust the liquid suction profile,effectively restrain profile faces backward phenomenon in the process of polymer flooding,so as to improve the heterogeneity reservoir oil displacement effect,but alternate cycle there is a best boundary,in terms of experimental simulation of heterogeneous reservoir,alternate cycle in 0.2 PV may obtain the best effect of oil displacement.Found on the order of alternating injection of high concentration polymer in the former way is better than low or high score low concentration in the former,then selected the best polymer alternate variable seepage resistance injection.Through the water absorbing ratio,recovery ratio,low permeability layer parameters such as contrast,heterogeneity,alternate cycle slug size 0.2 PV,oil displacement effect is better than the alternate cycle of 0.1 0.4 PV and PV displacement solution;Alternate cycle slug size of 0.2 PV,best oil displacement effect of alternating sequence first high scores,high consistency,and high grades,strong alternating sequence,after injection for 2000 PV,mg/L polymer flooding recovery efficiency reached 34.51%,ultimate recovery reached 74.86%;Alternating high concentrated high marks in the former order,better than the low grade or low concentration in the alternating injection before the order.