Study On The Synthesis And Properties Of The Heat And Salt Resistant Drag Reduction In Hrine

Brine is a kind of underground resources with very wide application. With the continuous development and growth of relevant brine industries, the demand for brine resources increased gradually. After decades of exploitation, shallow underground brine reserves showed a downward trend, so the exploitation and application of deep underground brine were paid more attention to. Compared with shallow underground brine, the exploitation of deep underground brine exist large investment and high operating cost problems, in which the energy costs of deep brine mining process accounted for large part of the total costs. Therefore, the most problems in the brine mining transport process are the drag reduction and reducing consumption of the process of conveying, looking for drag reduction agent that can significantly reduce the energy consumption in the mining transport when was added to the brine.Polyacrylamide (PAM) is the most commonly used water soluble drag reduction agent, and have very good drag reduction effect in pure water. But deep underground brine has the characteristics of high temperature and high salt, while PAM molecule is sensitive to salt. When PAM was added to the salt brine molecules will become curly, drag reduction effect decline. At high temperature the molecular stability of PAM drop, and drag reduction effect is affected. So the use of commonly used water soluble drag reduction agent PAM is limited. The drag reduction agent that apply to the brine mining process must have the heat resistance and salt resistance, the most effective method is the synthesis of modified polyacrylamide polymer, for example, the introduction of heat resistant and salt resistant groups or hydrophobic associating polymer synthesis.In this experiment, there are two types of modified polyacrylamide were synthesized:one is the introduction with sulfonic acid root structure of 2-acrylamide-2-methyl propane sulfonic acid (AMPS); The other is introduced with a hydrophobic groups of eighteenth methacrylate (SMA) hydrophobic associating polymer synthesis.1、The acrylamide and 2-acrylamide-2-methyl propane sulfonic acid polymer P (AM/AMPS) was synthesized by the method of aqueous solution polymerization. The reason of introducing AMPS, on one hand, AMPS has a lot of side chain, can enhance the rigidity of the molecular chain, increasing the molecular space steric hindrance, boosting the molecular stability; On the other hand, the sulfonic acid root that on the molecular chain of AMPS has a strong resistance to salt, can improve the salt resistance of polymers. The optimal synthetic conditions were determined by orthogonal experiment. Infrared analysis, nuclear magnetic resonance (NMR) were used to determine the structure of polymer, and the molecular weight of polymer was measured by multi Angle laser light scattering.2、The introduction of the eighteenth methacrylate (SMA) that containing hydrophobic groups to the acrylamide and 2-acrylamide-2-methyl propane sulfonic acid polymer. The hydrophobic groups not only can occur intra-molecular and intermolecular association to form a mesh structure, increase the stability of molecular, but also the big side chain of SMA can enhance the rigidity of the molecular chain, the polymer has good heat resistance and salt resistance. And use nuclear magnetic resonance (NMR) to determine the structure of the polymer.The drag reduction rate of P (AM/AMPS) and P (AM/AMPS/SMA) in different salt brine, and the drag reduction rate trend along with the change of temperature were determined respectively, then compared the drag reduction effect with that of the PAM. The experimental results show that:1,The drag reduction rate of drag reduction agent decreased with the rise of temperature and the increase of salinity. Under the condition that the temperature is at 80℃, the salt content of brine is 150 g/L and the concentration of drag reduction agent is 20ppm, drag reduction rate of P (AM/AMPS) was 31.75%, and that of PAM 12.90%. It shows that the drag reduction effect of P (AM/AMPS) is better than that of PAM in high temperature brine. In other words, synthetic polymer has excellent heat resistance and salt resistance.2, The introduction of hydrophobic groups in the polymer enhanced the drag effect of P (AM/AMPS/SMA). Under the condition that the temperature is at 80℃, the salt content of brine is 150 g/L and the concentration of drag reduction agent is 20ppm, drag reduction rate of P(AM/AMPS/SAM) was 36.51% in 80℃, high than that of P(AM/AMPS) under the same conditions. The results show that the introduction of hydrophobic groups further improves the heat resistance and salt resistance ability of drag reduction agent.According to the mechanism of polymer drag reduction, the drag reduction rate of drag reduction agent has certain relation between the kinematic viscosity. As the kinematic viscosity and drag reduction rate of polymer solution were measured, it is concluded that the drag reduction rate and the kinematic viscosity have the same variation tendency. So as the relationship between the kinematic viscosity of the polymer were known, the relationship between the drag reduction rate can be concluded.