致密油藏低伤害醇基压裂液体系的研究与应用

致密砂岩油藏具有渗透率低、吼道细小、填隙物含量高等特点,因此要求压裂液必须具有低伤害,较高的返排能力和防膨能力的特点.为此,制备得到了低分子量,低粘(基液粘度小于10mPa·s),压后能够有效破胶、易返排的多羟基醇压裂液体系.通过对该体系的流变性能、残渣含量、静态滤失特性、表面张力、破胶液防膨性能及对岩心伤害等进行室内实验评价,证明该压裂液抗剪切能力较强、破胶水化彻底、无残渣、滤失低、表界面张力低、能防止黏土膨胀、对地层损害小.现场10口井的现场试验表明,应用多羟基醇压裂液,平均返排率80%,平均单井试排产量增加6m3/d,实施效果显著.

The research and application of low damage alcohol-based fracturing fluid in tight oil reservoir

Tight oil reservoir has the characteristics of low permeability , small throat and high filler content ,therefore the fracturing fluid must have properties of low damage ,strong ability of backflow and anti-swelling .The polyhydroxy-alcohol fracturing fluid system with low molecular weight ,low viscosity （base fluid viscosity is less than 10） ,gel breaking effec-tively and easy backflow was prepared .Rheological properties ,the content of residue ,the static filtration characteristics ,surface tension ,gel breaking liquid anti-swelling properties and core damage have been tested in lab .Results of lab testing show that the shear perform-ance is stronger ,fracturing fluid can be fully breaking without residue ,and fracturing fluid has low filtration rate ,low surface tension ,better anti-swelling property and low formation damage .Ten well tests received significant effect ,which the average backflow rate is 80%and average oil increment is 6 m3/d .