Research of the relationship between the chain length of the dialkyl phosphate ester and the oil-based fracturing fluid viscosity

For the usage of dialkylphosphate as a gelatinizer in oil based fracturing fluid, there are two methods of preparation involved: 1.The improved ethylphosphate method is used to control one of the ester chains by using single alcohol substitute for mixed alcohols; 2.The new method of polyphosphate is used to control both of ester chains. Different kinds of alcohols are used as the raw materials in 3×3 orthogonal experiment (ratio of reactants, reaction temperature and reaction time) to obtain the optimum reaction conditions. Furthermore, 14 kinds of gelatinizers are produced by these experiments. The viscosity of the products is used as an evaluation index. The results based on these two methods show that there is a positive correlation between the length of dialkylphosphate ester chain and the viscosity of the fracturing fluid in a certain number of carbon atoms. In other words, the viscosity of fracturing fluid increased with an increasing length of the ester chain length, and reached the maximum at C13. Then the growth slowed down. The viscosity of the products which were produced by the polyphosphate method has been obviously improved by 7.72%-45.35% at the level of the other