一种窜流通道高强度封堵剂的制备与性能

Development and Performance of the High Strength Plugging Agent for Channeling-path

针对大庆外围油田压裂后存在注入水突进、压裂裂缝见水等问题,采用水溶液聚合法合成了抑制窜流通道的高强度封堵剂,以保障后续重复压裂措施对潜力部位的有效挖潜。通过室内实验对封堵剂进行配方优化和性能评价,优选的配方为5%~10%丙烯酰胺+0.1%~0.5%N,N'-亚甲基双丙烯酰胺+0.03%~0.1%过硫酸铵+20%~25%偶联改性G级油井水泥。该封堵剂适用于40~65℃地层,初始黏度为10~15 mPa·s,成胶时间为1~5 h可控,具有较好的注入性能。封堵剂成胶强度为30~300 N可调,岩心封堵率大于98%,突破压力超过20MPa,具有较好的封堵性能。该高强度封堵剂适用于封堵原有压裂裂缝出水通道和射孔孔眼,保证重复压裂时裂缝转向而形成新缝,同时也适用于封堵天然裂缝形成的窜流通道,对油田后续重复压裂措施的有效开展、实现控水增油提供有利的技术支持。

In view of the problems of breakthrough of injection water and fracture after fracturing in Daqing peripheral oilfields,the high strength plugging agent of controlling channeling path was synthesized by aqueous solution polymerization method,which ensured the effective exploitation of potential placement by subsequent refracturing measures.The formula optimization and performance evaluation of the plugging agent were carried out through laboratory experiments.The optimized formula was 5%—10%acrylamide,0.1%—0.5%N,N'-methylenebisacrylamide,0.03%—0.1%ammonium persulfate and 20%—25%coupling modified class G oil well cement.The plugging agent was suitable for the formation with the temperature of 40—65℃.The initial viscosity of the plugging agent was 10—15 mPa·s,and the gelling time was controllable within 1—5 hours,which indicated that the plugging agent had good injectivity.The gelling strength of the plugging agent could be adjusted from 30 N to 300 N.The core plugging rate was greater than 98%,and the breakthrough pressure was more than 20 MPa,exhibiting good plugging performance.The high strength plugging agent was suitable for plugging the water exit of the original fracture and perforation,which ensured the fracture diversion and forming new fractures during the refracturing.At the same time,it was also suitable for plugging the channeling-path formed by natural fracture.It could provide favorable technical support for the effective development of subsequent refracturing measures and realizing water control and oil increment.