用于海水基压裂液环氧丙基表面活性剂改性胍胶的制备与性能评价

Synthesis and Performance Evaluation of Guar Gum Modified with Glycidyl Surfactant for Seawater-based Fracturing Fluid

张永涛 郭布民 金颢 鲍文辉 秦世利 邱守美 张强 赵健

ZHANG Yongtao GUO Bumin JIN Hao BAOWenhui QIN Shili QIU Shoumei ZHANG Qiang ZHAO Jian

针对海水中存在大量金属离子附着在胍胶表面，抑制胍胶分子的溶胀，不能满足现场连续混配的问题，以 环氧氯丙烷、十八烯酸酰胺丙基二甲基丙胺为原料制得阳离子单体（GOA），再将GOA接枝到胍胶分子链上，得 到海水基压裂液稠化剂环氧丙基表面活性剂改性胍胶。研究了GOA改性胍胶的溶胀、耐盐、耐温耐剪切、携砂 与破胶等性能。结果表明，改性胍胶分子链上的库仑力及静电排斥等作用避免了金属离子附着在胍胶分子链 上，保证了胍胶分子的溶胀，提高了胍胶的耐盐性。GOA改性胍胶在海水中的溶解速度明显大于普通胍胶，在 海水中的粒径中值约为普通胍胶分子的1/5。在转速800 r/min 下，GOA改性胍胶溶胀约5 min 的黏度即能达到 最终黏度的80%。微观形貌分析结果表明，GOA改性胍胶形成了无规则网状线团结构，胍胶分子链充分展开的 同时交联点位增多。GOA改性胍胶压裂液具有较好的抗盐和耐温耐剪切性能，在160 ℃、170 s-1下连续剪切 120 min 后的黏度仍高于50 mPa·s，且破胶液黏度为1.6 mPa·s，破胶液中的残渣含量为297 mg/L，满足现场压裂 施工需求。

A large number of metal ions in seawater attach to the surface of guar gum，which inhibits the swelling of guar gum molecules and cannot meet the requirement of continuous mixing on site. The cationic monomer GOA was synthesized by using epichlorohydrin and octadecenoic acid amidopropyl dimethylpropylamine as raw materials. And then the GOA was grafted onto the guar gum molecular chain to obtain the seawater-based fracturing fluid thickener glycidyl surfactant-modified guar gum. The swelling，salt resistance，temperature and shear resistance，sand carrying and gel breaking properties of GOA modified guar gum were studied. The results showed that the coulomb force and electrostatic repulsion on the modified guar gum molecular chain prevented metal ions from attaching to the guar gum molecular chain，ensured the swelling of guar gum molecule，and then improved the salt tolerance of guar gum. The dissolution rate of GOA modified guar gum in seawater was significantly higher than that of ordinary guar gum，while the median particle size in seawater was about 1/5 of that of ordinary guar gum. When the rotation speed was 800 r/min，the viscosity of the gel could reach 80% of the final viscosity after it was swollen for about 5 min. Microscopic analysis showed that the GOA modified guar gum formed a clearly visible random network coil structure. The guar gum molecular chain fully expanded. Meanwhile，the number of cross-linking bonds increased. The viscosity after continuous shearing at 160 ℃ and 170 s-1 for 120 min was still higher than 50 mPa·s，indicating that the GOA modified guar fracturing fluid had good salt resistance，temperature resistance，shear resistance. The viscosity of breaking fluid was 1.6 mPa·s，the residue content in gel breaking fluid was 297 mg/L at the same time，which could meet the needs of on-site fracturing construction.

10.19346/j.cnki.1000-4092.2023.02.008