蒸汽驱用碱木素冻胶酚醛树脂交联剂的研制

Preparation of Alkali Lignin Jelly Cross-Linking Phenolic Resin Used for Steam Flooding

刘高文

LIU Gao-Wen

碱木素冻胶是一种较好的可用于蒸汽驱的高温堵剂，但作为其交联剂的酚醛树脂由石化产品苯酚和甲醛合成，费用相对较高。对碱木素进行羟甲基化改性提高其化学活性，然后用羟甲基化碱木素（HKLF）部分取代甲阶酚醛树脂(CPF)合成了碱木素甲醛树脂。其最佳合成条件为：NaOH用量占原料总质量的0.75%，反应时间3.5 h，反应温度85℃，碱木素和甲醛质量比3:1，HKLF取代CPF的比例为20%。用10%碱木素与4%碱木素甲醛树脂交联剂配制成碱木素冻胶溶液（pH=10.00）。成胶前的初始黏度为3.8 mPa·s (25℃)，泵入性能好；室温下以3000 r/min搅拌5 h，冻胶强度损失为5.44%，抗剪切性良好；200℃下的成胶时间为1.5 h，冻胶强度达到最大值0.092 MPa，成胶温度范围为120~250℃；可在200℃放置1个半月，强度损失为4.12%，热稳定性良好。岩心封堵实验结果表明，随着填砂管堵前渗透率的减小，突破压力增大，封堵率减小，蒸汽突破压力最低为3.52 MPa，封堵率最小值为96.6%；渗透率级差越大，碱木素冻胶进入高渗透层越多，剖面改善率最高可达3.638。与CPF相比，碱木素甲醛树脂性能较好，价格低。

Alkali lignin was one better kind of plugging agent which could be used for steam flooding. But phenolic resin served as alkali lignin cross-linking agent was synthesized by phenol and formaldehyde which resulted in relatively high cost. The chemical activity of alkali lignin was improved after hydroxymethylation reaction. And the product, HKLF, partially substituted for resol to synthesize alkali lignin formaldehyde resin. The optimum reaction condition was obtained as follows: 0.75% NaOH dosage, 3.5 hrs reaction time, 85℃ reaction temperature, 3:1 alkali and formaldehyde mass ratio, 20% replacing proportion of HKLF and resol. Alkali lignin gel solution with 10.00 pH value was prepare by mixing 10% alkali lignin and 4% alkali lignin resin crosslinking agent. The initial viscosity was 3.8 mPa·s at 25℃ before gel, and the performance in pumping was good. The gel strength loss was 5.44% after rabbling 5 hrs with 3000 r/min at room temperature which demonstrated a perfect anti-shear stability. The gel strength of cross-linked alkali lignin was 0.092 MPa and gelling time was 1.5 hrs at 200℃. Gelling temperature range was 120—250℃. The gel strength loss was 4.12% after placing at 200℃ one and a half months which showed a good thermal stability. The core plugging experiment results showed that the breakthrough pressure increased and the plugging rate reduced with decreasing pro-permeability of sand filling tube. The lowest steam breakthrough pressure was 3.52 MPa and the minimum plugging rate was 96.6%. The greater permeability contrast, the more alkali lignin gel got into high permeable zone. The highest profile-improve rate was 3.638. Compared with resol, alkali lignin formaldehyde resin had a better performance and lower price.