调剖用延缓交联剂MLH-1的研制

Preparation of Delay-Action Crosslinker MLH-1 for Aqueous Polymer Gelling Fluid in Use for Water Injectivity Profile Modification

对于大庆油田处理注水井近井地带所用的HPAM/Cr3 + 冻胶调剖剂 ,要求调剖剂溶液在井温条件下 (4 5℃ )成胶时间在 10— 30h范围内可调 ,形成的冻胶强度高 (以表观粘度表示 ,为 5× 10 4 — 1.5× 10 5mPa·s) ,因此需要使用性能符合要求的延缓型交联剂。实验考察了 3种氧化还原型铬交联剂交联 1%HPAM水溶液的能力。重铬酸钠 /木质素磺酸钠氧化还原体系使溶液成胶的配比范围很窄且成胶速率过高 ,成胶时间太短。重铬酸钠 /硫脲氧化还原体系只有在重铬酸钠用量很高时 (≥ 1.5 % )才能使溶液延缓成胶 ,这在经济上是难以接受的。适当配比的重铬酸钠 /木质素磺酸钠 /硫脲氧化还原体系 (延缓型铬交联剂MLH 1) ,可使HPAM溶液的成胶时间在 5— 30h范围内调节 ,形成的冻胶表现粘度一般大于 1.5× 10 5mPa·s。以本质素磺酸钠与重铬酸钠间的诱导反应 ,硫脲与重铬酸钠间的受诱反应解释了MLH 1的延缓交联作用。HPAM /MLH 1体系已成功地用于大庆油田 36口注水井近井地带的调剖作业。

The polymer/Cr 3+ gelling fluid for treating near bore zones of water injection wells at Daqing should become gel of high strength( of app viscosity 50-150 Pa·s) in a controllable time ranged 10-30 hrs at reservoir temperature 45℃. A proper delay action crosslinker is needed. For this purpose 3 redux systems are investigated experimentally. 1% HPAM solution gelates very fast in a rather short time only with a sodium bidchromate/sodium lignosulfate system of narrowly ranged mass ratios. Bichromate/thiourea system is a delay action crosslinker when bichromate use level is high(≥1.5%) and this is not economically acceptable. A properly formulated bichromate/lignosulfate/thiourea redux system(delay action crosslinker MHL 1) can gelate 1% HPAM solution in 5-30 hrs controllably and the gel formed is strong( of app viscosity>150 Pa·s). The delay action of MHL 1 is explained in terms of inducing reactions between lignosulfate and bichromate and of induced reactions between thiourea and bichromate. The HPAM/MLH 1 gelling fluid has been successfully used in injectivity profile modification operations in 36 wells at Daqing.