Effect Of Heteroaromatic Pendants In Comb Copolymers On Flow Ability Of Crude Oil

Due to the flocculation and deposition of paraffin and asphaltenes may induce a series of risks on oil exploitation and petroleum transportation industry, this work is aimed to study the effect of different pendants in comb-type copolymers on flow ability of crude oil and the interaction mechanism of copolymers.Waxy oil from Liaohe oilfiled is chosen as the research object. Asphaltenes extracted from waxy oil was used to prepare model oil, which has the similar and simple component with crude oil. Poly (maleic acid amide-a-octadecene) with benzimidazole pendants (MACB), octadecyl (MACO) and phenylpendants (MACP) were synthesized through chemical modification. By controlling the ratio of monomer, MACB copolymers with different amination degree were synthesis.1H NMR was used to characterize the structure of copolymers and the amidation ratio was calculated throuth spectrogram.Rheological measurements, polarizing light/fluorescent microscope, differential scanning calorimetry (DSC), and X-ray diffraction (XRD) are introduced to study the influence of copolymer on rheological property, crystallization behavior and thermodynamic property of paraffins and asphaltenes aggregation condition of crude oil. Compared with MACO and MACP copolymers, MACB are more efficient in reducing the yield stress of both model oil and crude oils with asphaltenes, in modifying the morphologyof wax crystals, in lowering the wax appearance temperature (WAT) and quantity of wax precipitation, andin decreasing the crystal size and crystallinity of paraffins. And the effect will be better with increasing amination of MACB.Due to the abundant polar and aromatic groups in asphaltene structure, the benzimidazolyl pendant in MACB can provide both hydrogen banding by amino groups and π-π stacking by benzyl group, and improve the interactions with asphaltens. As a result, the asphaltenes will be prevented from aggregation and can help to stabilize paraffin crystals in oils as they have been reported as natural surfactant in oil. Therefore, by increasing the interactions with asphaltenes, MACB show the best performance to prevent the paraffin disposition from oils upon cooling. MACP have phenyl pendants which can form π-π stacking with aromatic groups, thus show stronger interactions with asphalenes than MACO, but weaker compared to MACB.This workwill provide theoretical and experimental foundation for designing efficient and novel copolymer flow modifier, shows great potential economic value.