高压注水井带压作业凝胶封堵体系性能评价

Performance Evaluation of Gel Plugging System for High Pressure Water Injection Well under Pressure Operation

汪万飞 付红

WANGWanfei FU Hong

为满足高压注水井带压作业对凝胶封堵体系的强度、成胶时间以及可破胶的性能要求，采用丙烯酰胺 （AM）/2-丙烯酰胺基-2-甲基丙磺酸（AMPS）为二元聚合物体系、三羟甲基化合物（Smel30）为交联剂制备了一种 耐温抗盐凝胶封堵体系。研究了温度、无机盐、模拟油含量、剪切时间对凝胶体系成胶时间和凝胶强度的影响， 同时研究了破胶剂过硫酸钠用量对凝胶体系破胶效果的影响。结果表明，温度由40 ℃升至100 ℃时，凝胶体系 的成胶时间由23.5 h 缩短至2.0 h、凝胶强度由39.4 Pa 增至88.6 Pa。无机盐可使聚合物链间距离减小，成胶时间 缩短，凝胶强度略有增加；3 种无机盐对凝胶体系成胶时间和凝胶强度的影响从小到大依次为NaCl＜MgCl2＜ CaCl2。凝胶体系抗油污和抗剪切能力较强。加入1%～10%的模拟油可使凝胶体系的成胶时间由8 h 增至15 h， 凝胶强度的变化较小；在60 ℃、500 r/min 的条件下剪切60 min 后，成胶时间从7 h 增至17 h，但凝胶强度仍能保 持81%。凝胶体系的热稳定性较好，在60 ℃老化15 d 未出现明显脱水，且凝胶强度为67 Pa。过硫酸钠可以高效 低成本破胶，按体积分数为30%的量在凝胶体系中加入质量分数为30%的过硫酸钠，60 ℃下的破胶时间为20 h， 残液表观黏度为64.4 mPa·s，可以通过气体或清水将破胶残液顶替至地面，易于返排，满足现场施工要求。

In order to meet the strength，gelling time and gel breaking performance requirements of the gel plugging system for high pressure water injection wells under pressure operation，a temperature-resistant and salt-resistant gel plugging system was developed. This system utilized acrylamide（AM）/2-acrylamido-2-methylpropanesulfonic acid（AMPS）as a binary polymer system and trimethylol compound（Smel30）as crosslinking agent. The effects of temperature，inorganic salt，simulated oil content，and shear time on gelling time and gel strength of the system were investigated. Additionally，the influence of sodium persulfate on gel breaking effect of the system was studied. The results showed that when the temperature increased from 40 ℃ to 100 ℃，the gelling time of the system decreased from 23.5 hours to 2.0 hours，while the gel strength increased from 39.4 Pa to 88.6 Pa. Inorganic salts could reduce the distance between polymer chains，which led to shorter gelation time and a slight increase in gel strength. Three inorganic salts were arranged according to the effects on gelling time and gel strength of the system in following order：NaCl < MgCl2 < CaCl2. The gel system exhibited strong resistance to oil stains and shear forces. The addition of 1%—10% simulated oil increased the gelation time from 8 hours to 15 hours，with minimal change in gel strength. After shearing at 60 ℃ and 500 r/min for 60 minutes，the gelling time increased from 7 hours to 17 hours，while the gel strength remained 81%. The gel system displayed good thermal stability. There was no significant dehydration after aging at 60 ℃ for 15 days，and then the gel strength remained at 67 Pa. Sodium persulfate was an effective and cost-efficient gel breaker. After adding 30%（mass fraction）sodium persulfate with dosage of 30% volume fraction to the gel system，the gel breaking time at 60 ℃ was 20 hours，and then the apparent viscosity of the residual liquid was 64.4 mPa·s. The gel breaking residual liquid could be easily displaced to the ground using gas or water， meeting on-site construction requirement.

10.19346/j.cnki.1000-4092.2023.04.009