表面活性剂-聚合物自组装酸化转向用聚合物AHD的合成

Synthesis of polymer AHD for surfactant-polymer self-assembly acidification

摘要:

为改善油藏储层非均质性，提高酸化施工作业效果。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，合成并研究了一种表面活性剂-聚合物自组装酸化转向用聚合物AHD，利用FTIR和GPC对产物结构进行了表征。通过AHD与十八烷基三甲基氯化铵（STAC）自组装形成酸化转向体系。90 ℃下，AHD加量为1.0 %、STAC加量为0.2 %（以HCl溶液总质量为基准），无需交联剂转向酸黏度从3 mPa·s增加到288 mPa·s，鲜酸黏度低于非交联聚合物转向酸，容易注入地层。油的加量为1.0 %时，可使残酸破胶后黏度低于10 mPa·s，保留了黏弹性表面活性剂型转向酸在遇油自动破胶，利于返排的优点。通过TEM与DLS研究机理发现Ca2+会促进表面活性剂-聚合物自组装体系形成更加庞大的聚集体，进而使转向酸得以转向。

Abstract:

In order to optimize the non-homogeneity of the reservoir to improve the effectiveness of acidizing operations, a self-assembled acidizing steering polymer named AHD, was synthesized in this study. Acrylamide (AM), sulfonate monomer (HSY) and octadecyl dimethyl allyl ammonium chloride (DMAAC-18) were used as functional monomers to obtain polymer AHD, which was characterized by FTIR and GPC. AHD could form steering acid system with trimethylstearylammonium chloride（STAC） by self-assembly. The viscosity of this system could increase from 3 mPa·s to 288 mPa·s without crosslinking agent when the addition of AHD and STAC was 1.0 % and 0.2 % (based on the total mass of HCl solution) at 90 ℃. Fresh acid was easier to introduce into the formatio because it had a lower viscosity than the non-crosslinked polymer steering acid’s viscosity. With 1.0 % oil addition, the viscosity of the spent acid after gel breaking was less than 10 mPas, maintaining the benefit of viscoelastic surfactant steering acid could gel break automatically in the situation of oil for backflow. According to the mechanism of the TEM and DLS investigations, Ca2+ encouraged the development of bigger aggregates in the surfactant-polymer self-assembly system, which allowed the steering acid to be diverted.