表面活性剂-聚合物自组装酸化转向用聚合物的合成

Synthesis of polymer for surfactant-polymer self-assembly acidification

以丙烯酰胺(AM)、磺酸盐单体(HSY)、十八烷基二甲基烯丙基氯化铵(DMAAC-18)为功能性单体,合成了一种表面活性剂-聚合物自组装酸化转向用聚合物(AHD),利用FTIR和GPC对AHD结构进行了表征。在质量分数为20%的盐酸中,通过AHD与十八烷基三甲基氯化铵(STAC)自组装形成非交联型聚合物转向酸溶液。在90℃下,当AHD添加量为1.0%、STAC添加量为0.2%(均以质量分数为20%的盐酸质量为基准,下同)时,非交联型聚合物转向酸溶液的黏度从3 mPa·s(鲜酸,即与碳酸钙反应前的转向酸溶液)增加到288 mPa·s〔残酸(即与碳酸钙完全反应后的转向酸溶液)〕,鲜酸黏度低容易注入地层。当油添加量为1.0%(以残酸质量为基准)时,可使残酸破胶后黏度<10 mPa·s,保留了黏弹性表面活性剂型转向酸在遇油类物质时,可以自动破胶利于返排的优点。通过TEM与DLS研究其转向机理发现,Ca^(2+)会促进表面活性剂-聚合物自组装体系形成更庞大的聚集体,进而使转向酸得以转向。

A polymer AHD for surfactant-polymer self-assembly acidification was synthesized from acrylamide(AM),sulfonate monomer(HSY)and octadecyl dimethyl allyl ammonium chloride(DMAAC-18),and characterized by FTIR and GPC.In 20%(mass fraction)hydrochloric acid,AHD and trimethylstearylammonium chloride(STAC)could form self-assembly acid system via self-assembly.The viscosity of this system,formed without crosslinking agent at 90℃with addition amount of AHD and STAC 1.0%and 0.2%respectively(based on the total mass of hydrochloric acid with 20%mass fraction),was increased from 3 mPa·s(fresh acid,that is the acid solution before reacting with calcium carbonate)to 288 mPa·s.It was easier to inject fresh acid into the stratum because fresh acid had a lower viscosity in comparison to the non-crosslinked polymer steering acid.When the oil added was 1.0%[based on the mass of spent acid(that is the acid solution after reacting with calcium carbonate completely)],the spent acid after gel breaking showed a viscosity of less than 10 mPa·s,maintaining the advantage that viscoelastic surfactant steering acid could automatically break the gel and facilitate flowback when encountering oil substances.TEM and DLS analyses indicated that Ca^(2+)promoted the development of bigger aggregates in the surfactant-polymer self-assembly system,which allowed the steering acid to be diverted.