Clear Autogenetic Heat Fracturing Fluid and Its Experiment

Several autogenetic heat fracturing fluids find their use in reservoir fracturing. In autogenetic heat fracturing, activating agent is added into the fracturing fluid for heat generation, and this makes the process much less efficient. A clear autogenetic fracturing fluid was prepared using a hydrophobic polymer as the thickening agent. The thickening agent has a salt-resistant component added during its synthesis, enabling the thickening agent to be readily dissolving in saltwater. Using organo-zirconiumacidic crosslinking agent, activating agent using for heat generation and modifying agent for crosslinking reaction are not necessary anymore. Fracturing fluid treated with 0.6% of the thickening agent has good heat-resistance and shear-resistance, good elasticity and gel breaking capacity. After shearing for 60 min at 100℃ and 170 s^-1, the fracturing fluid retains a viscosity of about 140 mPa·s, and its visco-elasticity equivalent to that of conventional guar gum fracturing fluids. Residue of the fracturing fluid is 11.9 mg/L. This fracturing fluid is suitable for use in fracturing medium-to low-temperature reservoirs. By monitoring pressure changes of the reaction, the extent of reaction of heat generators is measured on a HTHP dynamic acidizing corrosion tester, and this measurement is both simple and accurate, suitable for the optimization of the formulation of autogenetic heat fracturing fluids, and the assessment of the extent of reaction of heat generators. The study shows that no reaction has ever taken place between heat generators in base fluid at 40℃, and 55% of the heat generators react at 80℃, while at 120℃, all heat generators react with each other, indicating that the fracturing fluid should be prepared in advance, and the operation process is the same as that of conventional fracturing fluids.