自转向土酸在青海油田储层改造中的应用

针对青海油田花土沟和尕斯区块储层多为薄互层,且层数多,跨度大,纵向非均质性严重,泥质含量较高等特征,为了消除储层突出的层间和层内矛盾,有效地改造油层,获得更好的产吸液剖面,通过室内实验形成并评价了以土酸为主体酸的自转向酸体系。该体系具有良好的增黏能力,能有效实现暂堵转向的目的,并且具有良好的耐高温流变性,与地层原油接触后能迅速破胶加快酸液返排。现场试验表明,土酸自转向酸酸化取得了明显的效果。

The Applications of Self-diverting Mud Acid During Reservior Stimulation in Qinghai Oilfield

Against the characteristics of reservoir in Huatugou Oilfield and Gasi Oilfield in Qinghai such as thin interbedded, multi-layered, large span, serious vertical heterogeneity, high clay content, a kind of viscoelastic surfactant self-diverting mud acid was developed and evaluated through laboratory experiments in order to eliminate the outstanding contradictions within and between layers to stimulate effectively and get a better production and injection profile. This acid system can viscosify well and achieve temporarily blocking effectively during acidification. In addition, this acid system has a good rheologic behavior at high temperatures and can degrade quickly when contacts with crude oil. Field tests showed that acidification used the self-diverting mud acid achieved remarkable effect.