海水基聚丙烯酰胺高温冻胶体系的研制与性能评价

Development and Evaluation of A Seawater-based and High Temperature Polyacrylamide Gel System

贾辉 丁名臣 王闯 朱毅仁 廖云虎 麻金海 宋新旺 王业飞

JIA Hui DING Mingchen WANG Chuang ZHU Yiren LIAO Yunhu MAJinhai SONG Xinwang WANG Yefei

南海A油田注气开发中，油井气油比急剧增大，气窜明显，为此开展了海水基高温冻胶封窜体系研究。选用非离子聚丙烯酰胺（NPAM）和酚醛体系作为主剂和交联剂，探索增大聚合物浓度、加入除氧剂和高温稳定剂3种方式增强冻胶高温稳定性效果；形成了海水基高温冻胶体系配方，并考察了其对天然气的耐受性和封堵能 力。结果表明：尽管采用高浓度聚合物能够增强冻胶热稳定性，但在125 ℃下，即使采用高浓度（0.8%）NPAM，冻胶老化48 h 后脱水率在90%以上；除氧剂的加入也难以显著改善冻胶热稳定性；高温稳定剂可明显增强冻胶的耐温性，是构筑海水基高温冻胶体系的关键组分。优化形成的海水基高温冻胶体系配方为：0.4% NPAM+0.3%乌洛托品+0.3%间苯二酚+0.8%稳定剂。该体系在125 ℃下的成胶时间为10～12 h，60 d 内仍能维持较好冻胶状态，不破胶；弹性模量大于1500 mPa，脱水率小于10%。冻胶能在高温高压环境下与天然气稳定共存，不破胶；冻胶能对岩心形成良好封堵，稳定残余阻力系数210，封堵率99.5%，且耐冲刷性较强。

During development of NH-A oilfield by gas injection，the gas-oil ratio measured in oil wells increases sharply， indicating the obvious gas channeling. To address this issue，a seawater-based and high temperature gel system was developed. Non-ionic polyacrylamide（NPAM）and phenolic system were selected as the main agent and crosslinking agent，three methods were explored to enhance the high-temperature stability of the gel by increasing polymer concentration，adding deaerators to inhibit polymer degradation and adding high temperature stabilizer. The crosslinking agent，high temperature stabilizer and polymer concentration optimization were carried out to form a seawater-based high temperature gel system. Finally，the natural gas tolerance and plugging ability of the system were evaluated. The results showed that，although the high-concentration polymer could enhance the thermal stability of gels，the dehydration rate of single-high-concentration（0.8%）non-ionic polyacrylamide gel was more than 90% after ageing for only 48 h. The presence of deoxidizer was also difficult to significantly enhance the thermal stability of gel. Fortunately，the high-temperature stabilizer could inhibit the interaction between the calcium，magnesium ions and the polymer， thus，obviously enhanced its temperature resistance，which was the key to the construction of seawater based high temperature gel system. The final gel formula formed by component-concentration optimization was：0.4% NPAM + 0.3% urotropine + 0.3% resorcinol + 0.8% stabilizer. It could maintain excellent colloidal state under high calcium，magnesium ion concentration，high temperature of 125 ℃ and natural gas condition，with a elastic modulus greater than 1500 mPa and a dehydration rate less than 10%. The gel could coexist with natural gas under high temperature and high pressure environment without breaking. It could form a good plugging on the core with a residual resistance coefficient of 210，a plugging rate of 99.5%，and a high scouring resistance.

10.19346/j.cnki.1000-4092.2022.02.014