The Synthesis Of Quaternary Ammonium Gemini Surfactant And Application In Fracturing Fluid

Oil and gas well fracturing technology is an effective way to transform hydrocarbon zone, and an effective measure way to increase production and injection of oil and gas wells. Fracturing fluid plays a crucial role in fracturing process. Fracturing exhibits its importance with the development of Daqing Oilfield external low-permeability oil field, and the advantages and disadvantages of fracturing fluid is the main factor of fracturing effect. Surfactant fracturing fluid is complex formulated by surfactant and additive agent, which has the characteristics of easy preparation, good rheological property, no gel breaker, easy-back, no residue and low harm to the formation. However, at present, the single species of surfactant used in surfactant fracturing fluid restricted its further development.Gemini surfactants can be formed higher viscosity at lower concentration, and this feature can be used in main agent of surfactant fracturing fluid. In this paper, three kinds of quaternary ammonium Gemini surfactants 12-2-12.2Br (N, N'- Double dodecyl dimethyla,ω-ethane bromide) ,14-2-14.2Br (N, N'-double tetradecyl dimethyl a,ω-ethane bromide) ,16-4-16.2 Br (N, N'-double cetyltrimethylamrnonium dimethyl a,ω-butane bromide) were synthetized, and theirs viscosity characteristics were tested, the results indicated that such surfactant has a high viscosity behavior, the fracturing fluid formulation (1.9% 16-4-16.2Br +1.1% NaSal) was optimized by complex formulating 16-4-16.2Br and additive agent, the 16-4-16.2Br, which has the best viscosity, is the main agent. The testing of the fracturing fluid's filter loss performance, rheological property, viscosity break property, and compatibility property with bottom water were completed. The results showed that: the fracturing fluid can meet the requirement of 80℃well temperature, and have the characteristics of low filter loss performance, viscosity break rapidly, easy anti-handling due to low viscosity after the viscosity break, the damage of rock permeability by viscosity break fluid is 10.6%, which lower 20 percents than guar gum fracturing fluid, it indicated that the fracturing fluid is low damage to the formation, Cl~- in formation water has the effect of increasing viscosity on the fracturing fluid, and other ions have no significant effects on the performance of the fracturing fluid. The value of pH has little influence on the fracturing fluid. The fracturing fluid has a certain using value, which provides the direction of subsequent development of fracturing fluid and will improve oil production at the same time.