适合二类油层驱油用抗盐聚合物的制备与性能评价

Preparation and Performance Evaluation of Salt-resistant Polymer for Oil Displacement in the Type II Oil Layers

韩培慧

HAN Peihui

大庆油田聚合物驱油已转向储层物性较差的二类油层。清水配液污水稀释常规部分水解聚丙烯酰胺 （HPAM）溶液不仅导致聚合物用量增加，而且致使聚合物驱效果变差。为降低聚合物用量，提高其注入能力，改 善聚合物驱技术效果，以丙烯酰胺（AM）、2-丙烯酰胺基-2-甲基丙磺酸（AMPS）、1-丙烯酰基-4-甲基哌嗪（AMP） 为单体，采用水溶液共聚再NaOH水解的合成方法，通过优化合成参数，制备了一种高分子量的抗盐共聚物AM/ AANa/AMPSNa/AMP（命名为聚合物A）。对比评价了聚合物A与同分子量HPAM的各项性能。结果表明，聚合 物A适宜的制备条件为：AM、AMPS、AMP的加量分别为20%~21%、7.5%~10%、0.1%~0.5%，复合引发体系 K2S2O8-NaHSO3、偶氮二异丙基咪唑啉盐酸盐（Va-044）占单体总质量的0.01%，初始引发温度为2℃，链转移剂异 丙醇加量占单体总质量的0.2%。聚合物A的抗盐、耐热稳定、黏弹性和注入能力等性能优于同分子量的HPAM， 1000 mg/L的聚合物A溶液可注入岩心渗透率下限为112×10-3 μm2，比HPAM低53×10-3 μm2。天然岩心驱油结果 表明，相同用量下聚合物A的采收率增幅比HPAM高4.2%。抗盐聚合物A耐热稳定性好、注入能力强，提高采收 率幅度高，适用于大庆油田二类油层的高效开发。图9表4 参20

Polymer flooding in Daqing oilfield has shifted to the type II oil layers with poorer physical properties. As the conventional partially hydrolyzed polyacrylamide（HPAM）for polymer flooding is prepared with clean water and then diluted with produced water，more polymer powders are consumed，leading to worse recovery factor. In order to reduce polymer consumption， improve the injectivity and effects of polymer flooding，a salt-resistant polymer with high molecular weight，AM/AANa/AMPSNa/ AMP（named polymer A），was synthesized with acrylamide（AM），2-acrylamido-2-methyl propanesulfonic acid（AMPS），and 1-acryloyl-4-methyl piperazine（AMP）. By optimizing the synthesis parameters，polymer A was firstly co-polymerized in water and then hydrolyzed with NaOH. General property evaluations for polymer A and HPAM with the same molecular weight were carried out. The results showed that the appropriate preparation condition of polymer A was obtained as follows：20%—21%，7.5%—10% and 0.1%—0.5% monomer dosages of AM，AMPS and AMP，0.01% initiators combination of K2S2O8-NaHSO3 and 2，2’-azobis［2- （2-imidazolin-2-yl）propane］ dihydrochloride（Va-044）dosage for total monomers in quality，0.2% chain transfer agent isopropyl alcohol dosage for total monomers in quality，2℃ initiation temperature. The salt-resistance，thermal stability，visco-elasticity and injectivity for polymer A were better than those of HPAM with the same molecular weight. The lower permeability limit for polymer A of 1000 mg/L was 112×10-3 μm2，which was lower than that of HPAM by 53×10-3 μm2. Natural core flooding experiment results showed that the enhanced recovery factor of polymer A was 4.2% higher than that of HPAM under the same consumption. Due to the better thermal stability，injectivity and higher recovery factor，polymer A was suitable for the efficient development of the type II oil layers in Daqing oilfield.