Improvement Of Oil Flow Ability By Comb-type Copolymers

Aiming to solve wax deposition and asphaltenes aggregation problems in crude oil. Two series of comb-type copolymers were synthesized in this thesis. Furthermore, their applicationes as flow improver in the crude oil were also studied in the follow part. Finally, the mechanism of the flow improvement of comb-type copolymers was explored based on the model oil and crude oil. The main work is shown as below:In the first part, maleic anhydride copolymers (MAC) with different ratios of maleic anhydride (MA) to amine were synthesized and the effect of these comb-type copolymers was evaluated by addition in model oil. Amination degree of MAC was determined by 1H NMR, decomposition temperature of MAC was tested by TGA and the molecular of MAC was determined by GPC. And their effects on crystallization of paraffin in waxy oil were characterized by rheometry, polarizing light microscopy, DSC and XRD. According to the results of rheology, it can be concluded that the high degree of amination leads to more hydrophobic alkyl side chain and thus benefit for reducing the size of paraffin crystals. However, higher aminated MAC didn't have good effects on crude oil. Due to higher degree of amination leads to more hydrophobic groups, the content of hydrophilic groups would be decreased correspondingly. When the crude oil only contained high content of paraffins, the higher aminated MAC would have a good effect on reducing the size of crystals, viscosity, and yield stress. When the crude oil contained high content of paraffins as well as asphaltenes, there would be an optimized ratio of the hydrophobic group to the hydrophilic group in MAC, which has a good effect on reducing the viscosity and yield stress of crude oil.In the second part, the maleic anhydride-a-octadecene copolymer was grafted with the oxyethyl groups by esherification named PMAC which could assemble with the asphaltenes molecules and disperse their aggregation status. The structure of PMAC was tested by 1H NMR, decomposition temperature of PMAC was tested by TGA and the molecular middle product of PMAC was determined by GPC. The effect of PMAC as the asphaltenes dispersant was evaluated by rheology and polarizing microscope (PLM). The experimental results showed that PMAC could well disperse the aggregated asphaltenes. And the dispersed asphaltenes as well as long alkyl chains of PMAC could provide local nucleation sites for waxy crystals which could depresse the size of the wax crystals, therefore, the viscosity of the crude oil was dropped drastically.According to the results of experiment, it is easily conclude that two kinds of comb-type copolymers which could be used to depressant the pour point of wax oil and viscosity of asphaltene oil respectively were synthesized. It is also conclude that MAC and PMAC have a distinct effect on dropping the energy consume in the process of oil transportation, therefore, they are excellent candidate for crude oil transportation and extraction.