三种驱油剂在聚驱后二维非均质物理模型上的驱油效果

Displacement Efficiency for Three Different EOR Chemical Agents in Two-Dimension Heterogeneous Physical Model after Polymer Flooding

在模拟大庆油田条件下,在3种VK值的二维纵向非均质人造岩心上,在45℃考察了水驱、1.0 g/L普浓聚合物驱之后,3种聚驱后驱油剂的驱油效果。所用聚合物为M=2.5×107,HD=26.5%的HPAM。这3种驱油剂的组成(g/L)为:12/5/1.4的Na2CO3/烷基苯石油磺酸盐/HPAM溶液(ASP);加入17.5 mg/L Cr3+的ASP(铬交联ASP);2.5 g/L高浓HPAM溶液。两种ASP体系与原油间界面张力在10-4mN/m量级。随岩心VK值增大,水驱采收率大幅度降低,普浓聚驱采收率增值显著升高,聚驱后驱油剂的采收率增值与岩心VK值和驱油剂类型有关。高浓聚合物、ASP、铬交联ASP的采收率增值,在VK=0.50岩心上分别为7.7%、10.6%、12.1%,在VK=0.65岩心上分别为7.8%、12.3%、22.5%,在VK=0.72岩心上分别为10.3%、9.8%、11.2%。铬交联ASP注入压力升幅大,后续注水压力维持高值;高浓聚合物溶液注入压力升幅较大或很大,但后续注水压力迅速下降;ASP注入压力升幅最小,后续注水压力不断下降。因此,聚驱后采用洗油效率特别是扩大波及体积能力更强的驱油剂,可以进一步提高采收率。图3表4参9。

The oil displacement efficiency of 0.38 PV of three different EOR chemical agents is investigated on 2D vertically heterogeneous artificial cores having been flooded by water and 0.64 PV of normal concentration, 1.0 g/L, polymer solution （NCPS） at 45℃ under simulation conditions of Daqing. The polymer used is an HYAM of M = 2.57×10^7 and HD = 26.5 %. The three EOR agents are： 12/5/1.4（in g/L） Na2CO3/alkyl benzene sulfonate/HPAM solution （ASP）; the ASP solution with 17.5 rng/L Cr^3＋ added （Cr-ASP） ; high concentration, 2.5 g/L, HPAM solution （HCPS）. The two ASP solutions create ultralow IF of 10^-4 mN/m with the crude oil. The oil recovery by water flood is significantly decreased and the oil recovery enhanced by NCPS flood is notably increased with increasing VK value of cores. The oil recovery ehanced by the EOR chemical agents under study is dependent upon both VK value of core and type of chemical agent and is of 7.7 %, 10.6 %, and 12.1% on cores of VK = 0.50, of 7.8 %, 12.3 %, and 22.5% on cores of VK = 0.65, and of 10.3% ,9.8%, and 11.2% on cores of VK = 0.72 for HCPS, ASP, and Cr-ASP, respectively. The injection pressure of Cr-ASP is raised dramatically and of water afterwardz is kept high and stable; of HCPS is raised significantly and of water afterwardz is lowered down speedly and of ASP is raised moderately and of water afterwards is lowered down fast. It is concluded that the oil recovery can be enhanced further and additionally after polymer tic（x] finished by injection of an EOR chemial fluid possessing more strong oil washing and, particularly, sweeping capabilities.