Synthesis And Performance Evaluation Of AM / AMPS And Cationic Hydrophobic Monomer Ternary Copolymer Fracturing Fluid Thickener

With the developing of oil and gas industry, it is necessary to transform the reservoir in order to exploit the oil and gas resources with high technical requirements. As one of the most important technology to transform the reservoir, hydraulic fracturing plays more and more important role in exploitation of oil and gas resources. In the fracturing process, the performance of the fracturing fluid is a key factor affecting the fracturing effect. Currently, the most commonly used is plant glue-based fracturing fluid, it shows good performance, but it has damage to the reservoir, and the price is much higher than before. The new clean fracturing fluid almost has no damage to the formation, but the poor thermal stability and high cost make it limited in application.Through the analysis of the performance of the existing fracturing fluids, and combined with the development of hydrophobic associating polymers, the synthesis of a hydrophobic associating polymer as the thickener of fracturing fluid was put forward.The long chain quaternary ammonium salt is synthesized as the hydrophobic monomer. The hydrophobic associating polymers of AM/AMPS and the hydrophobic monomer were synthesized by free radical copolymerization in aqueous solution. The factors of reaction temperature, reaction time, total monomer concentration, pH, amount of initiator, the content of AMPS and hydrophobic monomer which effect the apparent viscosity of the reaction product, are studied. The relationship between the apparent viscosity and the polymer concentration is studied and the result shows that the critical aggregation concentration of HAPAM-16and HAPAM-18is1420mg/L and1330mg/L. The effect of salts concentrations on the apparent viscosity are studied, the results shows that the polymer solution has good salt resistance performances. When the concentration of SDBS reaches to lmmol/L, the apparent viscosity has a maximum value. Fluorescence spectroscopy and scanning electron microscopy are used to study the network structure formed via intermolecular hydrophobic associations, the result shows that the intermolecular interaction enhances with the increasing polymer content.The performance polymer fracturing fluid are measured according to water-based fracturing fluid performance evaluation standards, the results show that hydrophobic associating polymer fracturing fluid system has good heat and shear resistance performances, and the maximum temperature of the polymer fracturing fluid up to100℃, the system has a good viscoelasticity and sand-carrying performance, the system can completely broken by conventional polymer fracturing fluid breaker and the broken glue fluid with no residue.