带压作业用自降解凝胶性能的评价

Performance Evaluation of Self-degrading Gel for Pressurized Operation

杨雪 廖锐全 汪瀛

YANG Xue LIAO Ruiquan WANG Ying

凝胶带压封隔技术要求凝胶所需的强度与其破胶性能的矛盾性限制了该技术的发展。鉴于外部破胶困 难，通过引入不稳定交联剂PLG与丙烯酰胺、丙烯酸共聚合成了一种PLG自降解凝胶，采用单一变量法研究了 配方组分浓度对凝胶降解时间的影响，通过单轴压缩实验探究了凝胶强度，通过热重分析与PEGDA凝胶对比分 析了PLGN凝胶的降解性能，探究了PLG凝胶的封堵性能。结果表明，PLG凝胶优化配方为：丙烯酸加量为7%、 丙烯酰胺加量为7%、不稳定交联剂PLG加量为0.4%、APS加量为0.3%。PLG凝胶的本体强度为55.1 N；热重分 析表明PLG凝胶具有优异的降解性能，相比PEGDA凝胶，PLG凝胶具有更短的降解时间。凝胶在60～100 ℃ 均可实现降解，温度越高降解时间越短。此外，凝胶封堵实验表明，凝胶在60～100 ℃均有较好的封堵能力，且 在凝胶封堵作业结束后不需要额外注入破胶剂。凝胶降解时间可以通过设计配方来控制，以实现凝胶的快速破 胶。该自降解凝胶可以作为油气井带压作业封堵剂。

The contradictory nature of gel band pressure sealing technology requiring the required strength of the gel and its gel-breaking properties has limited the development of this technology. In view of the difficulty of external gel breaking，a self-degrading gel was formed by introducing an unstable cross-linker PLG co-polymerized with acrylamide and acrylic acid. the effect of the concentration of formulation components on the gel degradation time was investigated by the univariate method. The gel strength was explored by uniaxial compression experiments，the degradation performance of PLG gel was analyzed by thermogravimetric analysis，which was compared with that of PEGDA gel. Finally，the sealing performance of the gel was explored. The results showed that the optimal recipe of the system was as follows，the acrylic acid dosage was 7%，acrylamide dosage was 7%，unstable cross-linker PLG dosage was 0.4%，ammonium persulfate dosage was 0.3%. The native strength of the gel was 55.1 N. Thermogravimetric analysis showed that PLG gel had excellent degradation performance，PLG gel possessed shorter degradation time compared with PEGDA gel. The gel could achieve degradation at the temperatures of 60—100 ℃，and the higher the temperature the shorter the degradation time. In addition，the gel sealing experiments showed that the gel had good sealing ability at the temperatures of 60—100 ℃ ，and no additional injection of gel breaker was needed after the gel blocking operation. The gel degradation time could be controlled by designing the formulation to achieve rapid gel breakage. This self-degrading gel could be used as a plugging agent for oil and gas well with pressure operation.

10.19346/j.cnki.1000-4092.2023.02.004