KGM高温堵剂的研制与性能评价

Performance and Evaluation of Konjac Glucomannan Plugging Agent for Water Control in High Temperature Reservoirs

魔芋葡甘露聚糖（KGM）是魔芋粉的主要成分,是已知植物胶中黏度最大的天然高分子多糖,韧性强、具有独特的凝胶性能。通过组分用量优选得到了KGM堵剂最佳配方：粗品KGM 6.0 g/L＋聚合物HPAM（M=2500×104,HD=25%）1500 mg/L＋增强剂1.0%（体积分数）＋硫脲100 mg/L。该优化配方堵剂热稳定性良好,在110℃下老化60 d后的胶体强度为G级,成胶时间随温度升高而缩短,在90~120℃的性能十分稳定。岩心封堵实验表明,随着堵剂注入量的增加,岩心封堵率提高,最高可达99%以上。对多孔介质的封堵率随堵后注水速度的增大而减小。该堵剂具有可被驱动性,泵入速度增大则突破压力与突破压力梯度越高。岩心注水冲刷50PV后的封堵率大于90%。KGM堵剂只封堵出水层,不封堵出油层,便于现场应用。

Konjac glucomannan（KGM） is the main component of konjac flour.It is the most sticky natural polymer polysaccharides in all the plant gum known.It has strong toughness and unique gel performance.An optimal formula of KGM plugging agent was worked out through ingredient dosage screening： crude KGM 6 g/L＋polymer HPAM（M=2.5×107,HD=25%） 1500 mg/L＋strengthening agent 1.0%（volume fraction）＋thiourea 100 mg/L.The thermal stability of formulated fluid was good and gel strength reached grade G after 60 days at 110℃.Gelling time of the fluid shortened with increasing temperature and the performance was very stable at the temperature from 90℃ to 120℃.The results of experiments showed that the blocking rate of the core increased with increasing plugging agent injection.The highest blocking rate of water could reach over 99%.After the porous media was blocked by the plugging agent,the blocking rate decreased with increasing water injection rate.The system had the property of being driven and breakthrough pressure and breakthrough pressure gradient were higher while pumping speed increasing.After the blocked core was flushed by the water 50 PV,the blocking rate of water was still over 90%.The gelling fluid only blocked water layer not the oil layer and was convenient for field application.