摘要
VES自转向酸具有"变黏、缓速、降滤、无伤害"的特征,其分流转向技术是近年来发展的实现大井段、多层系储层改造新方法,在国内外分流转向施工中得到了广泛应用。针对使用VES自转向酸施工后需要很长返排期才能达到最大产能、体系存在破胶困难的问题,本文模拟了不同剪切速率以及处于不同区域的VES流体的破胶性能。测试结果发现,具有黏弹性的VES流体的破胶速率及破胶程度与剪切速率有关,且存在临界剪切应力——流体的屈服应力;在中、高剪切速率下VES流体能快速完全破胶,而在低剪切或不剪切的环境下,VES流体破胶很困难;处于多孔介质内的黏弹性流体破胶同样非常困难,但可以通过增加后置互溶剂用量,提高VES流体的破胶效果,减小对储层的伤害。
VES self-diversion acid has the characteristics of viscosifying,retarding reaction rate,reducing leakage of acid and no damage,and it can realize long interval and multilayer reservoir acidizing stimulation,which has been widely used.However,the VES system causes damage to reservoirs which needs a long time to reach the maximum production.In this paper,the gel breaking performances of VES fluid at different shear rate and different region has been studied.The experimental results show that there is critical shear stress in VES fluid—— the fluid yield stress,and it is relate to shear rate and breaking degree.At high shear rate,the VES fluid can break completely,but at low,it is very difficult to break.Moreover,the viscoelastic fluid in porous media is difficult to break,but increasing the amount of mutual solvent can improve the breaking effect of VES fluid which can reduce the damage to reservoirs.
出处
《钻井液与完井液》
CAS
2011年第4期60-63,96,共4页
Drilling Fluid & Completion Fluid
基金
国家自然科学基金项目"缝洞型碳酸盐岩油气藏酸蚀蚓孔基础理论研究"(50774064)
关键词
酸化
分流转向技术
VES自转向酸
破胶
Acidizing,Diversion acidizing technology
VES Self-diversion acid
Gel breaking.
