Experimental Study On Increasing Oil Recovery After ASP Flooding In Heterogeneous Reservoirs

The ternary compound flooding is a kind of tertiary oil recovery technology which is proposed to improve the oil recovery rate in the later stage of oilfield exploitation.The ternary compound flooding includes ASP flooding and weak alkaline.Because the ternary compound flooding causes serious damage to formation of the reservoir,it is of great significance to study the effect of the ASP flooding system on the oil recovery.In this paper,the viscosity of the polymer,the binary system of polymer and surfactant,the ternary composite system and the polymer gel were studied by viscosity test method in Daqing Xingshugang Oilfield.In the three-pipe homogeneous core,the ASP flooding,alkali-free binary flooding,high concentration polymer flooding,"gel 1+ weak alkaline ternary composite system","gel 2+ bulk swelling particles" + no alkaline ternary complex system "," gel 1 + alkali-free binary composite system "and" gel 2 + body swelling particles + alkali-free binary composite system "drive to improve oil recovery efficiency experimental study.The experimental study on the effect of high concentration polymer and "profile control agent + weak alkaline ASP flooding" on enhanced oil recovery was carried out under the condition of "five-point method" physical simulation model.The results show that the shunt ratio of the high-permeability layer is reduced and the medium-low permeability layer is increased during the initial and medium-stage flooding process.When the infiltration came into the middle and late period,the low permeability layer shunt rate decreased,the high permeability layer shunt rate increased,that is,the so-called "profile reversal" phenomenon;and transfer agent cleaning capacity,compared to its ability to expand yield contribution rate is larged.Therefore,the strong alkali three-phase compound flooding injection control agent must have a stronger flow control and washing capacity,the only way to greatly improve the recovery rate;in the five-point simulation model,the strong ASP composite system,the "high pressure polymer solution" and "gel 2 + body swelling particles + weak alkaline ternary system" can be further enhanced by "constant pressure experiment" method,and the oil recovery rate is 11.5% and 12.9% respectively.In the five-point simulation model,the remaining oil in the strong alkaline ternary flooding is mainly in the infiltration layer away from the injection zone and the whole low permeability layer;the high concentration polymer flooding and the "gel 2 + body swelling particles + weak alkaline ternary" driven by the object is mainly part of the remaining oil.From the economic aspects of consideration,the strong alkaline ASP composite is drive recommended after the injection of 0.7 PV high concentration polymer solution.From the technical aspects of the consideration,the strong alkaline ASP composite drive is recommended after the injection of "0.1 PV(gel 2 + body swelling particles)+0.35 PV weak alkaline main slug +0.15 PV weak alkaline sub-slug +0.1 PV follow-up polymer" combination.