海上油田耐温耐钙镁盐调驱体系研制

Experimental Study on Thermophilic,Calcium-tolerant and Magnesium-tolerant Profile Control Agents in Offshore Reservoir

常规冻胶体系在钙镁离子含量较高的海上油田的稳定性较差。为了提高冻胶的耐钙镁盐能力,制备了一种由耐温非离子聚合物KF、有机醛类交联剂REL和有机酚类交联剂MNE和稳定剂WZ组成的耐温耐盐有机交联聚合物体系。利用成冻强度代码法和突破真空度法考察了聚合物质量分数、交联剂质量分数、稳定剂质量分数、温度、矿化度等因素对体系性能的影响。在此基础上优化出了130℃条件下适于某油田的冻胶体系配方：0.3%数0.6%耐温聚合物KF＋0.3%数0.9%交联剂REL＋交联剂0.3%数0.9%MNE＋2%稳定剂WZ,该体系成胶时间4数50 h可调,成冻强度在0.040数0.089 MPa可调。配方为0.6%聚合物KF＋0.6%交联剂REL＋0.6%交联剂MNE＋2%稳定剂WZ的成胶体系在高温（130℃）、高矿化度（一价盐2.0×10^5mg/L或二价盐8.0×10^3mg/L）条件下老化30 d体积保留率大于90%;经不同程度的岩心剪切后放置在130℃条件下老化30 d未发生脱水现象,且水驱10 PV封堵率仍保持90%以上,显示出较好的耐温抗盐性能和持续封堵能力。

For high temperature offshore reservoir with high content of calcium and magnesium ion,the stability of the conventional gel systems is poor. To improve the gel＇s tolerance to calcium and magnesium,thermophilic and halotolerant organically cross-linked polymer system was prepared with thermophilic nonionic polymer KF,organic aldehyde cross-linking agent REL,organic phenol cross-linking agent MNE and stabilizer WZ. The effect of polymer, cross-linking agents and stabilizer concentrations,temperature,salinity on gelling property was evaluated with the method of gel strength classification and breakthrough vacuum method. The best formula of the system for the reservoir was confirmed. The appropriate recipe at the temperature of 130℃was as follows,the KF dosage was 0.3%—0.6%,the REL dosage was 0.3%—0.9%,the MNE dosage was0.3%—0.9%,and the WZ dosage was 2%. The gelation time could be controlled in the range of 4—50 h and the gel strength could be controlled in the range of 0.040—0.089 MPa. The lab experiment showed that the gel system containing 0.6% KF,0.6% REL,0.6% MNE and 2%WZ was thermophilic and halotolerant,while the volume retention was more than 90% after placed for 30 days in the environment of high temperature of 130℃ and high salinity of 2.0×10^5mg/L monovalent salt or 8.0×10^3mg/L divalent salt.The crosslinking system also had good shear resistance property and the volume retention was 100% after 30 days in the environment of high temperature（130℃）after different extent of shearing. Moreover,the system had consistent performance of flushing resistance,while plugging rate was still above 90% after 10 PV water flooding.