Study and Application of a High Temperature Salt-Resistant Fracturing Fluid Formulated with a Cationic Thickening Agent

In view of the current fracturing operations toward high-temperature oil and gas reservoir measures, water saving, mixing fracturing fluid by seawater or high salinity water, and other unconventional areas of development based on the study of the mechanism of hydrophobic associative polymer fracturing fluid, a self-association high salt-resistant fracturing fluid system was developed using the principle of anion and cation suction. Performance evaluation and field application of this kind of fracturing fluid system were carried out. Results show that addition of the anionic surfactant named dodecylbenzenesulfonic acid to the cationic polymer solution made the polymer molecules occur self associative reaction of electrostatic attraction; the addition of spherical micelles, calcium and magnesium ion stabilizer, enhanced the anti-temperature and salt resistance performance of the fracturing fluid.The fracturing fluid system viscosity can reach 331 mPa·s, it's salt resistant to 60,000 mg·L^-1 and it has good resistance to calcium and magnesium,the core damage is lower than other fracturing, and the viscosity can be maintained above 50 mPa·s at 130℃and 170 s^-1 shear 1h, which can meet the requirements of water temperature distribution and fracturing construction at the temperature of 60-130℃. Moreover, the viscosity of the fracturing fluid decreases with the increase of shear rate and the viscosity will be restored when the shear rate decreases,this shows that it can effectively reduce the friction resistance.The system is applied in the field of 3-26 well in the Erlian of North China oil field,It uses the mineralization degree of 9,104 mg·L^-1 of the formation of water directly to the liquid, which can improve the construction efficiency and increase the oil effect obviously.This system is easy to get raw materials, low cost, salt resistance is better than other fracturing fluid system, so it has a good application prospect.