压裂液延迟交联与快速破胶技术

针对压裂液伤害地层的问题，通过对压裂液延迟交联与快速破胶技术的研究试验，研制出了时间延迟交联剂和温度延迟交联剂．确定了压裂液在不同温度和不同时间内破胶时需要破胶剂的用量。结果表明．压裂液交联的最佳时间是压裂液刚进入地层的那一刻。为减少压裂液对地层的伤害，破胶剂加量应根据施工时问与裂缝中压裂液温度情况，使压裂液的破胶时间与施工时间相一致，既能保证压裂液的造缝与携砂能力，又能使压裂液在施工结束后快速破胶、水化返排。现场应用表明，压裂液具有摩阻低、抗剪切性能好、造缝与携砂能力强。对地层伤害小的优点．满足了现场施工的需要，提高了油井(特别是深井)压裂施工的成功率。在华北冀中对井深3400～3800m的油井压裂施工9口，平均砂比为29．3％，成功率为100％。

Delayed crosslink and rapid break techniques of fracturing fluid

A time delayed crosslinker and a temperature delayed crosslinker have been developed based on experiment of delayer crosslink and rapid break of fracturing fluid to cope with formation damage caused by fracturing fluid. The breaker dosage used for fracturing fluid in different temperature and different time has been determined. Research shows that the reasonable crosslink time of fracture fluid is the moment that the fracture fluid just enters the formation. To reduce damage of formation, the breaker dosageshould comply with the treating time and fracture fluid temperature, and fluid break time should comply with the treating time, so that, not only the making fracture and proppant-carrying capacities of the fluid can be remained but also rapid break and flowback of the fracture fluid after the fracturing job can be accelerated. A fracture fluid made from time delayed crosslinker and temperature delayed crosslinker has been used in field and the results show that the fracture fluid has many advantages such as low friction drag, good shear-thinning property, strong making fracture and proppant-carrying capacities, and little damage to formation, etc.. The average proppant concentration of 29. 3% and success ratio of 100% have been obtained in fracturing operation in nine deep wells of 3400-3800 m in Huabei oilfield.