南堡油田东营组试验区作业入井液体系储层保护技术研究

In-flowing Fluid System of Formation Protection in the Test Area of Dongying Formation of Nanpu Oilfield

根据南堡油田东营组试验区储层特征,分析了其潜在的储层损害因素,并对南堡油田常用的7种作业入井液基本理化性能进行了测试分析。在此基础上,对南堡油田东营组试验区不同类型的作业入井液体系的储层保护效果进行了评价。结果表明,密度为1.20g/cm3的优质压井液/普通压井液、微泡修井液以及2%NH4Cl+10%解水锁剂的储层保护效果好,污染后岩心的渗透率恢复值均大于90%;密度为1.05g/cm3普通压井液污染岩心的渗透率恢复值为50%左右;活性水、2%NH4Cl、2%KCl储层保护性能偏差;单一使用固化水对岩心损害较为严重,建议与破胶液联合使用,用3%破胶剂JPC溶液进一步污染岩心后最终渗透率恢复值可大于95%。

According to the reservoir features of Dongying Formation in Nanpu Oilfield,the potential formation damage factors and the physical and chemical properties of 7kinds of operating fluids used in Nanpu Oilfield were tested and analyzed.On the basis mentioned above,the effects of formation protection of the 7 commonly used in-flowing fluids in the test area of Nanpu Oilfield were evaluated.The results show that killing fluid of fine quality(1.2g/cm3),normal killing fluid(1.2g/cm3),microbubble workover fluid and 2% NH4 Cl+10% water-locking removal agent can protect reservoirs effectively.The permeability recovery rate of cores is more than 90% after polluted by the above fluids.The permeability recovery rate of cores is more than 50% after polluted by normal killing fluid(1.05g/cm3).Active water,2% NH4 Cl and 2% KCl are weaker in protecting reservoirs.The formation damage is more serious by using solidifying water as single fluid.It is proposed to use gel breaker as combined fluid.The permeability recovery rate of cores can be more than 95%after further polluted by 3% gel breaker JPC.