加重压裂液的研究与应用

Study and application of weighted fracturing fluid

压裂液加重是解决高温深井酸化压裂施工压力高、压开难度大的重要手段之一,实验优化形成了能够满足不同加重要求的加重压裂液配方,并对其性能进行了系统的室内评价。结果表明,研制的加重压裂液溶胀性能良好,压裂液密度与盐含量呈线性关系,压裂液密度最高可达1.43g/cm3;随着盐含量增加,压裂液冻胶黏度将大幅下降,稳定性也随之降低,但通过增加交联剂用量可提高加重压裂液在高温下的稳定性;其延迟交联性能能够较好地降低施工管路摩阻,4.0m3/min排量下降阻率达39.9%;在高温(>90℃)环境下能实现快速破胶,破胶液表面张力低(28mN/m);支撑裂缝导流能力伤害率为7%～21%。结合现场一口井对加重压裂液密度优化思路进行了详细的阐述。

Heavyweight of fracturing fluid is one of the important methods to solve high well head pressure and difficulty in breaking down the formation of acid fracturing and hydraulic frac- turing. Formula of weighted fracturing fluid is optimized for meeting different heavyweight re- quirements, a systematic evaluation is given to its properties in laboratory. The results show that the swelling ability of weighted fracturing fluid is good. The density of weighted fracturing fluid is linear to the salt content, the highest density is 1.43 g/cm3. The gel viscosity and stability of the fracturing fluid decrease with the increase of salt content, but increasing erosslinking agent dosage can improve the stability of the weighted fracturing fluid in a high temperature environ- ment. Retarded crosslinking performance of the fluid can greatly reduce the friction, friction-re- ducing ratio is up to 39.9%. The weighted fracturing fluid can be broken quickly in a high tem- perature environment（〉90℃）, the surface tension is 28 mN/m. The damage rate of conductivi- ty of propping fractures is 7%-21%. Based on a field deep well, the optimization ideas for the density of weighted fracturing fluid is described in detail.